Preface

This book presents important information about the structure of cellulose as well as its uses and applications.

In Chapter 1, "Insights from over 10 Years of Cellulosic Biofuel Modeling", Daniel Inman et al. present insights gained from more than ten years of system dynamic modeling of cellulose to the biofuel industry in the United States. They use a publicly available Biomass Scenario Model to explore the impact of logistics, economies of scale, and shared industrial learning on the developing cellulose-to-biofuels industry in the United States. One theme from this study as well as from the work performed over the last decade is the importance of the movement of the system toward maturation, both in terms of the supply system and the conversion processes. Mature processes imply lower investment risk, better yields, and better process economics.

In Chapter 2, "Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic Biorefinery", María E. Eugenio Martín et al. study the use of non-wood raw materials to obtain cellulosic fibers. There exists a renewed interest in the use of non-woody raw materials due to them being an abundant source of low-cost fibers. In addition, they are sometimes the only exploitable source of fibers in certain geographical areas, mainly in developing countries. Moreover, the great variety of characteristics, fiber dimensions, and chemical composition of these alternative raw materials give them great potential to produce different types of papers. The pulp and paper industry is an excellent starting point for the development of lignocellulosic biorefineries, possessing the necessary technology and infrastructure as well as extensive experience in lignocellulosic biomass transformation.

In Chapter 3, "Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose Materials", Sunday Samuel Oluyamo and Mathew Adefusika Adekoya show the influence of size classification on the properties of cellulose materials. Their study focuses on the influence of size classifications on the structural and solid-state characterization of cellulose obtained from wood dust. The isolated cellulose exhibits good mechanical and solid-state properties with promising applications in device utilization.

In Chapter 4, "An Update on Overview of Cellulose, Its Structure and Applications", Praveen Kumar Gupta et al. review the chemistry of cellulose, its extraction, and the properties that help various industries to make the most of it. Cellulose is one of the most ubiquitous organic polymers on the planet. It is a significant structural component of the primary cell wall of green plants, various forms of algae, and oomycetes. It is a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. There are various extraction procedures for cellulose developed by using different processes like oxidation, etherification, and esterification that convert the prepared celluloses into cellulose derivatives. Since it is a non-toxic, bio-degradable polymer with high tensile and compressive strength, cellulose has widespread use in various fields such as

nanotechnology, pharmaceuticals, the food industry, cosmetics, the textile and paper industry, and drug-delivery systems.

In Chapter 5, "Microbial Cellulases: An Overview and Applications", S. K. Jayasekara and R. R. Ratnayake present a review on cellulases, which are a complex group of enzymes secreted by a broad range of microorganisms including fungi, bacteria, and actinomycetes. They discuss the structure, function, possible applications, and novel biotechnological trends of cellulase enzymes. Furthermore, they examine the possibility of using low-cost, enzymatic pretreatment methods of lignocellulosic material in order to use it as an efficient raw material for biofuel production.

In the final sixth chapter, "Multi-Finishing of Polyester and Polyester Cotton Blend Fabrics Activated by Enzymatic Treatment and Loaded with Zinc Oxide Nanoparticles", Al-Balakocy N.G. et al. discuss the possibility of applying enzymatic treatments for fabric surface activation that can facilitate the loading of zinc oxide nanoparticles (ZnO NPs) onto polyester (PET) and polyester cotton blend (PET/C) fabrics prepared by sol-gel method.

We would like to thank the management at IntechOpen for their support while editing this book.

> **Alejandro Rodríguez Pascual** Professor, Chemical Engineering Department, Universidad de Córdoba, Spain

#### **María E. Eugenio Martín**

**1**

Section 1

Reviews

Tenured scientist, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Madrid, Spain

Section 1 Reviews

**3**

**Chapter 1**

**Abstract**

cellulosic biofuel

**1. Introduction**

(https://github.com/NREL/bsm-public).

results from the publicly-available version1

<sup>1</sup> https://github.com/NREL/bsm-public; git commit # e62598a.

**1.1 Biofuels in the United States**

*and Steve Peterson*

Insights from over 10 Years of

imply lower investment risk, better yields, and better process economics.

**Keywords:** system dynamics, biofuels, biomass, modeling, renewable energy,

The Biomass Scenario Model (BSM), developed by the U.S. Department of Energy (DOE), is used to explore the emerging biofuels industry in the United States. Over the course of the last decade, the model has evolved along with the biofuels industry. This evolution includes numerous upgrades to the model and associated software, updates to the underlying data, and public release of the model

The BSM has supported multiple analysis studies focused on various components of the feedstocks-to-biofuels supply chain; links to publications and reports associated with these studies can be found on NREL's OpenEI BSM wiki pages (https://openei. org/wiki/Biomass\_Scenario\_Model). Two important themes, which serve as focal points for this chapter, have emerged from our analyses: (a) the importance of feedstock logistics and (b) the impact of shared industrial learning. We present illustrative

Biofuels—specifically soy-based biodiesel and corn-starch-based ethanol (**Figure 1**)—have benefited from government support within the United States. Both the ethanol and biodiesel markets have grown following the Energy Tax Act [1], a law passed by the federal government in 1978 to promote fuel efficiency with

of the BSM that explore both themes.

*Daniel Inman, Emily Newes, Brian Bush, Laura Vimmerstedt* 

We present insights gained from over 10 years of system dynamic modeling of the cellulose to biofuel industry in the United States. We use a publicly-available Biomass Scenario Model to explore the impact of logistics system, economies of scale, and shared industrial learning on the developing cellulose-to-biofuels industry in the United States. One theme from this study as well as from the work performed over the last decade is the importance of the movement of the system toward maturation, both in terms of the supply system and the conversion processes. Mature processes

Cellulosic Biofuel Modeling

#### **Chapter 1**

## Insights from over 10 Years of Cellulosic Biofuel Modeling

*Daniel Inman, Emily Newes, Brian Bush, Laura Vimmerstedt and Steve Peterson*

#### **Abstract**

We present insights gained from over 10 years of system dynamic modeling of the cellulose to biofuel industry in the United States. We use a publicly-available Biomass Scenario Model to explore the impact of logistics system, economies of scale, and shared industrial learning on the developing cellulose-to-biofuels industry in the United States. One theme from this study as well as from the work performed over the last decade is the importance of the movement of the system toward maturation, both in terms of the supply system and the conversion processes. Mature processes imply lower investment risk, better yields, and better process economics.

**Keywords:** system dynamics, biofuels, biomass, modeling, renewable energy, cellulosic biofuel

#### **1. Introduction**

The Biomass Scenario Model (BSM), developed by the U.S. Department of Energy (DOE), is used to explore the emerging biofuels industry in the United States. Over the course of the last decade, the model has evolved along with the biofuels industry. This evolution includes numerous upgrades to the model and associated software, updates to the underlying data, and public release of the model (https://github.com/NREL/bsm-public).

The BSM has supported multiple analysis studies focused on various components of the feedstocks-to-biofuels supply chain; links to publications and reports associated with these studies can be found on NREL's OpenEI BSM wiki pages (https://openei. org/wiki/Biomass\_Scenario\_Model). Two important themes, which serve as focal points for this chapter, have emerged from our analyses: (a) the importance of feedstock logistics and (b) the impact of shared industrial learning. We present illustrative results from the publicly-available version1 of the BSM that explore both themes.

#### **1.1 Biofuels in the United States**

Biofuels—specifically soy-based biodiesel and corn-starch-based ethanol (**Figure 1**)—have benefited from government support within the United States. Both the ethanol and biodiesel markets have grown following the Energy Tax Act [1], a law passed by the federal government in 1978 to promote fuel efficiency with

<sup>1</sup> https://github.com/NREL/bsm-public; git commit # e62598a.

**Figure 1.**

*Growth of the ethanol industry and a timeline of major biofuel legislation.*

favorable tax incentives. Other government measures, such as guaranteed loans and research funds, helped de-risk the markets further [2].

Ethanol received another boost when methyl tertiary butyl ether (MTBE) was banned [3], which opened new markets for ethanol as an oxygenate in gasoline. Ethanol use in gasoline was reinforced a year later with the 2015 passing of the Energy Policy Act [4], which removed oxygenation requirements and mandated that refiners blend up to 10% ethanol by volume [5], adhering to the new Renewable Fuels Standard.

From 1978 to 2005, energy policies continued to favor the domestic ethanol industry through production tax credits and capitol grants, among other industry incentives. The passing of the Energy Independence and Security Act of 2007 slanted in favor of lignocellulosic ethanol—increasing biofuel volume requirements while incentivizing lignocellulosic feedstocks over corn starch through Renewable Identification Numbers (RINs) [5].

Ethanol continues to be the primary biofuel in the US. However, because of limits on blending, incompatible distribution and dispensing equipment, and limited market penetration of vehicles capable of using high ethanol blends (~ E-85), the overall biofuel market has been limited and less than anticipated volumetric goals reported in early legislation [6]. Additionally, much of the ethanol blended in the US is derived from cornstarch, which is classified as a "renewable fuel" by the EPA, meaning the fuel achieves a 20% reduction in CO2 as compared to conventional gasoline. To develop a more environmentally sustainable biofuels industry in the US, corn -starch-based ethanol is limited to 15 billion gallons annually, whereas lignocellulosic biofuels are incentive through their eligibility for D5 and D3 RINs. Despite legislation that provides incentives for advanced and cellulosic biofuels, the market for such fuels has been slow to take off.

One factor that has limited the market for advanced and cellulosic biofuels is the development of integrated biorefineries. The technologies for converting lignocellulosic feedstocks into ethanol and hydrocarbons are underdeveloped.Technologies for

**5**

**Figure 2.**

*Insights from over 10 Years of Cellulosic Biofuel Modeling DOI: http://dx.doi.org/10.5772/intechopen.84874*

markets for biomass feedstocks may not exist altogether.

feedstock species, and programs that incentivize producers [10].

sion making of various agents along the supply chain.

*A basic stock-flow structure and corresponding mathematical representation.*

**1.3 System dynamics modeling**

explanation of these concepts.

**1.2 The Biomass Scenario Model**

feedstock processing and handling have, at best, recently become commercial, and the

Many of the physical processes, decision processes, feedbacks and constraints found in the biomass-to-biofuels supply chain are represented in the BSM [11]. The BSM is a system dynamics model developed under the auspices of the DOE as part of a multi-year project at the National Renewable Energy Laboratory. It is a tool designed to better understand biofuels policy as it impacts the development of the supply chain for biofuels in the United States and the economic agents influencing development through their decisions. The model is intended to generate and explore plausible scenarios for the evolution of a biofuel transportation fuel industry in the United States, representing multiple pathways leading to the production of fuel ethanol as well as advanced biofuels such as biomass-based hydrocarbons such as biomass-based gasoline, diesel, jet fuel, and butanol. The BSM, which is implemented using the STELLA [12] system dynamics simulation platform, integrates representations of resource availability, physical/technological/economic constraints, behavior, and policy to model dynamic interactions across the supply chain. It simulates the deployment of biofuels given technological development and the reaction of the investment community to those technologies in the context of land availability, the competing oil market, consumer demand for biofuels, and government policies over time. It has a strong emphasis on the behavior and deci-

System dynamics is used in a wide range of modeling applications to represent and simulate complex non-linear systems driven by multiple interacting physical and social components. As a modeling philosophy, system dynamics relies on three key concepts: stocks, flows, and system feedback [13]. **Figure 2** shows a basic stockflow structure and corresponding mathematical representation. Below is a brief

These biorefineries are gaining support from both public and private channels [7]. Among the former, both the DOE and the U.S. Department of Agriculture (USDA) have helped commercialize renewable, non-starch biofuels and development of feedstock supplies. Their R&D leadership in the sector has helped develop lignocellulosic feedstocks and has gone beyond biofuels to include growth in bioproducts and biopower [8]. The USDA is also empowering the sector through its Biorefinery Assistance Program, which guarantees loans for biorefineries [9], and through research into alternative

*Cellulose*

**Figure 1.**

favorable tax incentives. Other government measures, such as guaranteed loans and

Ethanol received another boost when methyl tertiary butyl ether (MTBE) was banned [3], which opened new markets for ethanol as an oxygenate in gasoline. Ethanol use in gasoline was reinforced a year later with the 2015 passing of the Energy Policy Act [4], which removed oxygenation requirements and mandated that refiners blend up to

From 1978 to 2005, energy policies continued to favor the domestic ethanol industry through production tax credits and capitol grants, among other industry incentives. The passing of the Energy Independence and Security Act of 2007 slanted in favor of lignocellulosic ethanol—increasing biofuel volume requirements while incentivizing lignocellulosic feedstocks over corn starch through Renewable

Ethanol continues to be the primary biofuel in the US. However, because of limits on blending, incompatible distribution and dispensing equipment, and limited market penetration of vehicles capable of using high ethanol blends (~ E-85), the overall biofuel market has been limited and less than anticipated volumetric goals reported in early legislation [6]. Additionally, much of the ethanol blended in the US is derived from cornstarch, which is classified as a "renewable fuel" by the EPA, meaning the fuel achieves a 20% reduction in CO2 as compared to conventional gasoline. To develop a more environmentally sustainable biofuels industry in the US, corn -starch-based ethanol is limited to 15 billion gallons annually, whereas lignocellulosic biofuels are incentive through their eligibility for D5 and D3 RINs. Despite legislation that provides incentives for advanced

One factor that has limited the market for advanced and cellulosic biofuels is the development of integrated biorefineries. The technologies for converting lignocellulosic feedstocks into ethanol and hydrocarbons are underdeveloped.Technologies for

10% ethanol by volume [5], adhering to the new Renewable Fuels Standard.

and cellulosic biofuels, the market for such fuels has been slow to take off.

research funds, helped de-risk the markets further [2].

*Growth of the ethanol industry and a timeline of major biofuel legislation.*

Identification Numbers (RINs) [5].

**4**

feedstock processing and handling have, at best, recently become commercial, and the markets for biomass feedstocks may not exist altogether.

These biorefineries are gaining support from both public and private channels [7]. Among the former, both the DOE and the U.S. Department of Agriculture (USDA) have helped commercialize renewable, non-starch biofuels and development of feedstock supplies. Their R&D leadership in the sector has helped develop lignocellulosic feedstocks and has gone beyond biofuels to include growth in bioproducts and biopower [8]. The USDA is also empowering the sector through its Biorefinery Assistance Program, which guarantees loans for biorefineries [9], and through research into alternative feedstock species, and programs that incentivize producers [10].

#### **1.2 The Biomass Scenario Model**

Many of the physical processes, decision processes, feedbacks and constraints found in the biomass-to-biofuels supply chain are represented in the BSM [11]. The BSM is a system dynamics model developed under the auspices of the DOE as part of a multi-year project at the National Renewable Energy Laboratory. It is a tool designed to better understand biofuels policy as it impacts the development of the supply chain for biofuels in the United States and the economic agents influencing development through their decisions. The model is intended to generate and explore plausible scenarios for the evolution of a biofuel transportation fuel industry in the United States, representing multiple pathways leading to the production of fuel ethanol as well as advanced biofuels such as biomass-based hydrocarbons such as biomass-based gasoline, diesel, jet fuel, and butanol. The BSM, which is implemented using the STELLA [12] system dynamics simulation platform, integrates representations of resource availability, physical/technological/economic constraints, behavior, and policy to model dynamic interactions across the supply chain. It simulates the deployment of biofuels given technological development and the reaction of the investment community to those technologies in the context of land availability, the competing oil market, consumer demand for biofuels, and government policies over time. It has a strong emphasis on the behavior and decision making of various agents along the supply chain.

#### **1.3 System dynamics modeling**

System dynamics is used in a wide range of modeling applications to represent and simulate complex non-linear systems driven by multiple interacting physical and social components. As a modeling philosophy, system dynamics relies on three key concepts: stocks, flows, and system feedback [13]. **Figure 2** shows a basic stockflow structure and corresponding mathematical representation. Below is a brief explanation of these concepts.

**Figure 2.**

*A basic stock-flow structure and corresponding mathematical representation.*

#### *1.3.1 Stocks and flows*

Accumulations, and the activities that cause accumulations to rise and fall over time, are fundamental to the generation of dynamics. System dynamics models are built up from stock and flow primitives. In the BSM, we use stocks to represent concepts such as prices, inventories, conversion facilities, and station owners who are contemplating investment in E85 tankage and dispensing equipment. Corresponding flows would include price changes; production, consumption, and shrinkage of inventories; investment or obsolescence of facilities; and deciding not to invest in tankage and equipment.

#### *1.3.2 Feedback*

Dynamic social systems can contain rich webs of feedback processes. Positive feedbacks tend to drive reinforcing growth in key quantities, while negative feedbacks support self-correcting behavior. In the BSM, we have sought to capture key feedbacks within and across each stage of the supply chain.

The BSM is built and designed using a top-down, modular approach representing the flow of feedstocks to flow down the supply chain to be converted into biofuels, with feedback mechanisms among and between the various modules. Our modeling approach respects the need for transparency, modularity, and extensibility. This enables standalone analysis of individual modules as well as testing of different module combinations. As shown in **Figure 3**, the model is framed as a set of interconnected sectors and modules. Each supply-chain element is modeled as a standalone module but is linked to the others to receive and provide feedback. The feedstock production module simulates the production of biomass as well as five major commodity crops (corn, wheat, soybeans, cotton, and other grains) through farmer decision logic, land allocation dynamics, new agricultural practices, markets, and prices. The feedstock logistics module models the harvesting, collection,

**7**

**Table 1.**

*Insights from over 10 Years of Cellulosic Biofuel Modeling DOI: http://dx.doi.org/10.5772/intechopen.84874*

ferences in key variables.

**2. Modeling approach**

storage, preprocessing, and transportation of biomass feedstocks from the field (or forest) to the biorefinery. The conversion module represents more than a dozen biofuel conversion technologies at pre-commercial and commercial scales. In the model, the biofuel produced in the conversion stage is then distributed to dispensing locations and end users. The model is solved numerically at a sub-monthly level and typically reports annual output for the 30–40-year timeframe. Modules receive and react to information in a response to, among other factors, industrial learning, project economics, installed infrastructure, consumer choices, and investment dynamics. The model is geographically stratified using the 10 USDA farm production regions [14] as a basis, which facilitates analysis of regional dif-

We used the BSM to examine the impacts of (1) feedstock format and logistics, (2) biorefinery economies of scale, and (3) the impacts of shared industrial learning between fuel production technologies. In order to understand potential synergies between logistics, scale, and shared learning we modeled 10 combinations of feedstock logistics and economies of scale (**Table 1**). The feedstock formats and logistics considered include bale-based and advanced densified formats. At present, in the United States, the advanced densified logistics system is under development and we do not yet know the mechanism(s) for how these innovations may infuse into the broader market. Because of this, we model the transition from the current bale-based system to the advanced densified system based on the extent to which a commercial-scale industry has taken hold within a given region. In other words, the market demand has to be sufficiently large before large-scale investment in advanced logistics systems is warranted. Therefore, the transition to an advanced densified feedstock system is based on the number of commercial-scale biorefineries that are constructed within a given region during a model simulation. It should be noted that this study is not intended to assess the mechanism by which the biofuels industry transitions to more advanced feedstock logistics systems, but instead is focused on the system-level impact of the different feedstock logistics systems. The feedstock logistics systems modeled in this study are: Bale—feedstock is delivered to the biorefinery from within a 50-mile radius and is harvested using conventional

**Combination Format Economies of scale Shared learning** 1 Bale 1 0 Densified A 1 0 Densified B 1 0 Densified A ≤2.5 0 Densified B ≤2.5 0 6 Bale 1 1 Densified A 1 1 Densified B 1 1 Densified A ≤2.5 1 Densified B ≤2.5 1

*Feedstock format and economies of scale combinations explored in this study.*

**Figure 3.**

*The modules in the BSM represent elements of the biomass-to-biofuels supply chain.*

*Insights from over 10 Years of Cellulosic Biofuel Modeling DOI: http://dx.doi.org/10.5772/intechopen.84874*

storage, preprocessing, and transportation of biomass feedstocks from the field (or forest) to the biorefinery. The conversion module represents more than a dozen biofuel conversion technologies at pre-commercial and commercial scales. In the model, the biofuel produced in the conversion stage is then distributed to dispensing locations and end users. The model is solved numerically at a sub-monthly level and typically reports annual output for the 30–40-year timeframe. Modules receive and react to information in a response to, among other factors, industrial learning, project economics, installed infrastructure, consumer choices, and investment dynamics. The model is geographically stratified using the 10 USDA farm production regions [14] as a basis, which facilitates analysis of regional differences in key variables.

#### **2. Modeling approach**

*Cellulose*

*1.3.1 Stocks and flows*

*1.3.2 Feedback*

Accumulations, and the activities that cause accumulations to rise and fall over time, are fundamental to the generation of dynamics. System dynamics models are built up from stock and flow primitives. In the BSM, we use stocks to represent concepts such as prices, inventories, conversion facilities, and station owners who are contemplating investment in E85 tankage and dispensing equipment. Corresponding flows would include price changes; production, consumption, and shrinkage of inventories; investment or obsolescence of facilities; and deciding not to invest in tankage and equipment.

Dynamic social systems can contain rich webs of feedback processes. Positive feedbacks tend to drive reinforcing growth in key quantities, while negative feedbacks support self-correcting behavior. In the BSM, we have sought to capture key

The BSM is built and designed using a top-down, modular approach represent-

ing the flow of feedstocks to flow down the supply chain to be converted into biofuels, with feedback mechanisms among and between the various modules. Our modeling approach respects the need for transparency, modularity, and extensibility. This enables standalone analysis of individual modules as well as testing of different module combinations. As shown in **Figure 3**, the model is framed as a set of interconnected sectors and modules. Each supply-chain element is modeled as a standalone module but is linked to the others to receive and provide feedback. The feedstock production module simulates the production of biomass as well as five major commodity crops (corn, wheat, soybeans, cotton, and other grains) through farmer decision logic, land allocation dynamics, new agricultural practices, markets, and prices. The feedstock logistics module models the harvesting, collection,

feedbacks within and across each stage of the supply chain.

*The modules in the BSM represent elements of the biomass-to-biofuels supply chain.*

**6**

**Figure 3.**

We used the BSM to examine the impacts of (1) feedstock format and logistics, (2) biorefinery economies of scale, and (3) the impacts of shared industrial learning between fuel production technologies. In order to understand potential synergies between logistics, scale, and shared learning we modeled 10 combinations of feedstock logistics and economies of scale (**Table 1**). The feedstock formats and logistics considered include bale-based and advanced densified formats. At present, in the United States, the advanced densified logistics system is under development and we do not yet know the mechanism(s) for how these innovations may infuse into the broader market. Because of this, we model the transition from the current bale-based system to the advanced densified system based on the extent to which a commercial-scale industry has taken hold within a given region. In other words, the market demand has to be sufficiently large before large-scale investment in advanced logistics systems is warranted. Therefore, the transition to an advanced densified feedstock system is based on the number of commercial-scale biorefineries that are constructed within a given region during a model simulation. It should be noted that this study is not intended to assess the mechanism by which the biofuels industry transitions to more advanced feedstock logistics systems, but instead is focused on the system-level impact of the different feedstock logistics systems. The feedstock logistics systems modeled in this study are: Bale—feedstock is delivered to the biorefinery from within a 50-mile radius and is harvested using conventional


**Table 1.** *Feedstock format and economies of scale combinations explored in this study.* agricultural equipment and transported via truck in large round bales; Densified *A*—feedstock is harvested and collected using advanced equipment and is densified and delivered to a centralized depot from which the refinery receives feedstock, transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the of one commercial-scale biorefinery (i.e. capable of processing 2,000 dry Mg per day) is constructed in the region; and Densified *B*—transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once five commercial-scale biorefineries (i.e. capable of processing 2,000 dry Mg per day) are constructed within a given region. We explored the impact of economies of scale by (1) holding the biorefinery scale constant at 2,000 dry Mg per day and (2) allowing the biorefineries to be constructed up to 2.5 times the base design case throughput of 2,000 dry Mg per day.

Shared learning (also known as spillover learning) is the process by which proximate industries have mutually beneficial conditions from accrued industrial learning (learning by doing). The process of industrial learning and shared learning has been documented in the literature [15, 16]. Examples of shared learning include knowledgeable employees working for different companies or different processes that use a technology purchased from a third party, movement of employees between firms, government-sponsored research being published in the open literature, informal sharing and/or trading of information through professional societies/conferences, and patents. In this study we explore two scenarios—(1) no shared learning between similar processes, (2) shared learning between similar processes (e.g., thermochemical processes learn from one another, biochemical processes learn from each other).

For this study, background model conditions include modeling incentives that are currently in-place and allowing them to end according to their legislative schedules. Specifically, we include the Low Carbon Fuel Standard of California, RIN credits, and the Biomass Crop Assistance Program [6, 17, 18]. For each of these we use historical data and allow them each to expire according to their respective schedules. The results and implications presented in this study should be viewed in the context of this minimal incentive environment.

#### **3. Insights**

#### **3.1 Feedstock logistics and economies of scale**

Insights reported herein should be considered in the context of the US Energy Information Administration's Reference oil price scenario. Overall, the impact of economies of scale is modest (**Figure 4**). However, the impact of feedstock format and logistics system is salient. The impact of feedstock format and logistics, without spillover learning, are shown in **Figures 5** and **6**. Moving from the status quo bale-based feedstock system to a densified advanced logistics system (Densified A and B) can facilitate higher volumes of feedstock production in response to higher demand for biofuels. Densified feedstock formats can be transported over longer distances, at lower costs, than bale-based systems, thus opening up larger areas of collection, enabling higher-throughput refineries, helping to insulate the system against risks associated with feedstock procurement (e.g., regional supply shocks such as those caused by drought, flooding, pests, etc.). Comparing simulations from the Densified A to those from Densified B, there is a clear advantage to moving to a densified feedstock supply system earlier in the simulation (Densified A transitions after construction of one commercial-scale facility whereas Densified B transitions after five commercial-scale facilities are constructed). Comparing feedstock and biofuel production levels, the system under the Densified A scenario begins growth earlier and reaches a sustained

**9**

*constructed in the model.*

**Figure 5.**

**Figure 4.**

*Insights from over 10 Years of Cellulosic Biofuel Modeling DOI: http://dx.doi.org/10.5772/intechopen.84874*

*Simulated cellulosic feedstock production for a 35-year period, in the United States, with and without economies of scale. Feedstock production volumes for three feedstock format and logistics systems. Bale—feedstock is delivered to the biorefinery from within a 50-mile radius and is harvested using conventional agricultural equipment and transported via truck in large round bales; Densified A—feedstock is harvested and collected using advanced equipment and is densified and delivered to a centralized depot from which the refinery receives feedstock, transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the of one commercial-scale biorefinery (i.e., capable of processing 2000 dry mg per day) is constructed in the model; and Densified B—transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the construction of five commercial-scale biorefineries* 

*Simulated cellulosic biofuel (ethanol and hydrocarbons) production for a 35-year period, in the United States. Fuel production volumes are shown for three feedstock format and logistics systems. Bale—feedstock is delivered to the biorefinery from within a 50-mile radius and is harvested using conventional agricultural equipment and transported via truck in large round bales; Densified A—feedstock is harvested and collected using advanced equipment and is densified and delivered to a refinery, transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the of one commercial-scale biorefinery (i.e., capable of processing 2000 dry mg per day) is constructed in the model; and Densified B—transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the construction of five commercial-scale biorefineries (i.e., capable of processing 2000 dry mg per day) is* 

*(i.e., capable of processing 2000 dry mg per day) is constructed in the model.*

*Insights from over 10 Years of Cellulosic Biofuel Modeling DOI: http://dx.doi.org/10.5772/intechopen.84874*

#### **Figure 4.**

*Cellulose*

agricultural equipment and transported via truck in large round bales; Densified *A*—feedstock is harvested and collected using advanced equipment and is densified and delivered to a centralized depot from which the refinery receives feedstock, transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the of one commercial-scale biorefinery (i.e. capable of processing 2,000 dry Mg per day) is constructed in the region; and Densified *B*—transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once five commercial-scale biorefineries (i.e. capable of processing 2,000 dry Mg per day) are constructed within a given region. We explored the impact of economies of scale by (1) holding the biorefinery scale constant at 2,000 dry Mg per day and (2) allowing the biorefineries to be constructed up to 2.5 times the base design case throughput of 2,000 dry Mg per day. Shared learning (also known as spillover learning) is the process by which proximate industries have mutually beneficial conditions from accrued industrial learning (learning by doing). The process of industrial learning and shared learning has been documented in the literature [15, 16]. Examples of shared learning include knowledgeable employees working for different companies or different processes that use a technology purchased from a third party, movement of employees between firms, government-sponsored research being published in the open literature, informal sharing and/or trading of information through professional societies/conferences, and patents. In this study we explore two scenarios—(1) no shared learning between similar processes, (2) shared learning between similar processes (e.g., thermochemical processes learn from one another,

For this study, background model conditions include modeling incentives that are currently in-place and allowing them to end according to their legislative schedules. Specifically, we include the Low Carbon Fuel Standard of California, RIN credits, and the Biomass Crop Assistance Program [6, 17, 18]. For each of these we use historical data and allow them each to expire according to their respective schedules. The results and implications presented in this study should be viewed in

Insights reported herein should be considered in the context of the US Energy Information Administration's Reference oil price scenario. Overall, the impact of economies of scale is modest (**Figure 4**). However, the impact of feedstock format and logistics system is salient. The impact of feedstock format and logistics, without spillover learning, are shown in **Figures 5** and **6**. Moving from the status quo bale-based feedstock system to a densified advanced logistics system (Densified A and B) can facilitate higher volumes of feedstock production in response to higher demand for biofuels. Densified feedstock formats can be transported over longer distances, at lower costs, than bale-based systems, thus opening up larger areas of collection, enabling higher-throughput refineries, helping to insulate the system against risks associated with feedstock procurement (e.g., regional supply shocks such as those caused by drought, flooding, pests, etc.). Comparing simulations from the Densified A to those from Densified B, there is a clear advantage to moving to a densified feedstock supply system earlier in the simulation (Densified A transitions after construction of one commercial-scale facility whereas Densified B transitions after five commercial-scale facilities are constructed). Comparing feedstock and biofuel production levels, the system under the Densified A scenario begins growth earlier and reaches a sustained

biochemical processes learn from each other).

the context of this minimal incentive environment.

**3.1 Feedstock logistics and economies of scale**

**8**

**3. Insights**

*Simulated cellulosic feedstock production for a 35-year period, in the United States, with and without economies of scale. Feedstock production volumes for three feedstock format and logistics systems. Bale—feedstock is delivered to the biorefinery from within a 50-mile radius and is harvested using conventional agricultural equipment and transported via truck in large round bales; Densified A—feedstock is harvested and collected using advanced equipment and is densified and delivered to a centralized depot from which the refinery receives feedstock, transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the of one commercial-scale biorefinery (i.e., capable of processing 2000 dry mg per day) is constructed in the model; and Densified B—transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the construction of five commercial-scale biorefineries (i.e., capable of processing 2000 dry mg per day) is constructed in the model.*

#### **Figure 5.**

*Simulated cellulosic biofuel (ethanol and hydrocarbons) production for a 35-year period, in the United States. Fuel production volumes are shown for three feedstock format and logistics systems. Bale—feedstock is delivered to the biorefinery from within a 50-mile radius and is harvested using conventional agricultural equipment and transported via truck in large round bales; Densified A—feedstock is harvested and collected using advanced equipment and is densified and delivered to a refinery, transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the of one commercial-scale biorefinery (i.e., capable of processing 2000 dry mg per day) is constructed in the model; and Densified B—transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the construction of five commercial-scale biorefineries (i.e., capable of processing 2000 dry mg per day) is constructed in the model.*

#### *Cellulose*

#### **Figure 6.**

*Simulated cellulosic feedstock production for a 35-year period, in the United States. Feedstock production volumes for three feedstock format and logistics systems. Bale—feedstock is delivered to the biorefinery from within a 50-mile radius and is harvested using conventional agricultural equipment and transported via truck in large round bales; Densified A—feedstock is harvested and collected using advanced equipment and is densified and delivered to a refinery, transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the of one commercial-scale biorefinery (i.e., capable of processing 2000 dry mg per day) is constructed in the model; and Densified B—transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the construction of five commercial-scale biorefineries (i.e., capable of processing 2000 dry mg per day) is constructed in the model.*

#### **Figure 7.**

*Simulated cellulosic ethanol and hydrocarbon production for a 35-year period in the United States, showing impact of spillover (or shared) learning across technology pathways and for three feedstock format and logistics systems. Bale—feedstock is delivered to the biorefinery from within a 50-mile radius and is harvested using conventional agricultural equipment and transported via truck in large round bales; Densified A—feedstock is harvested and collected using advanced equipment and is densified and delivered to a centralized depot from which the refinery receives feedstock, transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the of one commercial-scale biorefinery (i.e., capable of processing 2000 dry mg per day) is constructed in the model; and Densified B—transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the construction of five commercial-scale biorefineries (i.e., capable of processing 2000 dry mg per day) is constructed in the model.*

**11**

**3.2 Shared learning**

**Figure 8.**

ment (**Figure 8**).

**4. Summary**

economics.

*Insights from over 10 Years of Cellulosic Biofuel Modeling DOI: http://dx.doi.org/10.5772/intechopen.84874*

*output varies in output varies in opposite direction from input.*

higher level of output. Industrial learning is a high-leverage nonlinear system parameter

*Causal loop diagram illustrating the reinforcing (positive) feedback loop among learning, maturity, investment attractiveness, and production, for two generic fuel production pathways (A and B). Note: (+) sign at arrowheads means that input and output tend to vary in the same direction; (−) sign at arrowhead means that* 

Simulated lignocellulosic biofuel production with and without shared learning, in the United States, is shown in **Figure 7**. Shared learning has been shown to exert [15, 16]. Shared learning has a marked impact on both cellulosic ethanol and hydrocarbon production. In the latter case, without shared learning, cellulosic hydrocarbons do not experience any appreciable production. Industrial learning is a key system lever and acts on the system through a positive feedback loop, whereby higher learning rates result in stronger relationship between production and growth in maturity, which increases the investment attractiveness. A technology that attracts more initial investment will then have more fuel production, with associated learning advances. This increase in maturity, and the associated improvements in cost and performance, raises the attractiveness of future invest-

A key theme from this study as well as from the work performed over the last decade is the importance of the movement of the system toward maturation, both in terms of the supply system and the conversion processes. On the feedstock supply side, advanced supply systems have advantages relative to bale in terms of transport, handling, storage, and losses. From the conversion process perspective, mature processes imply lower investment risk, better yields, and better process

in which small changes early on result in large differences later in the simulation.

*Insights from over 10 Years of Cellulosic Biofuel Modeling DOI: http://dx.doi.org/10.5772/intechopen.84874*

#### **Figure 8.**

*Cellulose*

**Figure 6.**

**10**

**Figure 7.**

*Simulated cellulosic ethanol and hydrocarbon production for a 35-year period in the United States, showing impact of spillover (or shared) learning across technology pathways and for three feedstock format and logistics systems. Bale—feedstock is delivered to the biorefinery from within a 50-mile radius and is harvested using conventional agricultural equipment and transported via truck in large round bales; Densified A—feedstock is harvested and collected using advanced equipment and is densified and delivered to a centralized depot from which the refinery receives feedstock, transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the of one commercial-scale biorefinery (i.e., capable of processing 2000 dry mg per day) is constructed in the model; and Densified B—transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the construction of five commercial-scale biorefineries (i.e., capable of processing 2000 dry mg per day) is constructed in the model.*

*Simulated cellulosic feedstock production for a 35-year period, in the United States. Feedstock production volumes for three feedstock format and logistics systems. Bale—feedstock is delivered to the biorefinery from within a 50-mile radius and is harvested using conventional agricultural equipment and transported via truck in large round bales; Densified A—feedstock is harvested and collected using advanced equipment and is densified and delivered to a refinery, transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the of one commercial-scale biorefinery (i.e., capable of processing 2000 dry mg per day) is constructed in the model; and Densified B—transition to an advanced system in which feedstock is harvested and collected using advanced equipment begins once the construction of five commercial-scale biorefineries (i.e., capable of processing 2000 dry mg per day) is constructed in the model.*

*Causal loop diagram illustrating the reinforcing (positive) feedback loop among learning, maturity, investment attractiveness, and production, for two generic fuel production pathways (A and B). Note: (+) sign at arrowheads means that input and output tend to vary in the same direction; (−) sign at arrowhead means that output varies in output varies in opposite direction from input.*

higher level of output. Industrial learning is a high-leverage nonlinear system parameter in which small changes early on result in large differences later in the simulation.

#### **3.2 Shared learning**

Simulated lignocellulosic biofuel production with and without shared learning, in the United States, is shown in **Figure 7**. Shared learning has been shown to exert [15, 16]. Shared learning has a marked impact on both cellulosic ethanol and hydrocarbon production. In the latter case, without shared learning, cellulosic hydrocarbons do not experience any appreciable production. Industrial learning is a key system lever and acts on the system through a positive feedback loop, whereby higher learning rates result in stronger relationship between production and growth in maturity, which increases the investment attractiveness. A technology that attracts more initial investment will then have more fuel production, with associated learning advances. This increase in maturity, and the associated improvements in cost and performance, raises the attractiveness of future investment (**Figure 8**).

#### **4. Summary**

A key theme from this study as well as from the work performed over the last decade is the importance of the movement of the system toward maturation, both in terms of the supply system and the conversion processes. On the feedstock supply side, advanced supply systems have advantages relative to bale in terms of transport, handling, storage, and losses. From the conversion process perspective, mature processes imply lower investment risk, better yields, and better process economics.

Our simulations suggest that it is beneficial for the feedstock supply system to transition away from short-distance (i.e., <50 miles) transport of bales and/or any other low-density formats, to a densified system modeled after the modern commodity grain system, using larger collection radii and centralized depots. Our simulations also suggest that the temporal component is substantial—earlier transition to a high density, commodity logistics system leads to the largest gains in cellulosic feedstock production and utilization—in our model, densified A scenario accelerates maturation of the feedstock supply 21. By the end of our simulation, the Densified A scenario results in ~15% greater feedstock production.

Industrial learning (learning by doing) is a key system lever in developing industries such as the biofuel/bioproducts industry. Because the industrial learning process follows a positive feedback loop, small perturbations have large system impacts. Shared learning amplifies the industrial learning process. Advances across similar industries are shared among the industries, resulting in a substantial positive impact on the industry. A potential extension would be to look at what percent of learning needs to be shared across similar technologies for a substantial increase in overall biofuel production.

### **Author details**

Daniel Inman1 \*, Emily Newes1 , Brian Bush1 , Laura Vimmerstedt1 and Steve Peterson2

1 The Strategic Energy Analysis Center, National Renewable Energy Laboratory, Golden, Colorado, USA

2 Thayer School of Engineering at Dartmouth College, Hanover, New Hampshire, USA

\*Address all correspondence to: daniel.inman@nrel.gov

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**13**

PLAW-110publ140

[7] Bacovsky D, Ludwiczek N, Ognissanto M, Worgetter M. Status

*Insights from over 10 Years of Cellulosic Biofuel Modeling DOI: http://dx.doi.org/10.5772/intechopen.84874*

> of Advanced Biofuels Demonstration Facilities in 2012: A Report to IEA Bioenergy Task 39 (No. T39-P1b). International Energy Agency; 2013. http://task39.sites.olt.ubc.ca/ files/2013/12/2013\_Bacovsky\_Statusof-Advanced-Biofuels-Demonstration-

Facilities-in-2012.pdf

may\_2013.pdf

113publ79.pdf

[8] U.S. Department of Energy. Bioenergy Technologies Office Multi-Year Program Plan. 2013. http:// bioenergy.energy.gov/pdfs/mypp\_

[9] U.S. Department of Agriculture. Biorefinery Assistance Program [WWW document]. 2015. Available from: http://www. rd.usda.gov/programs-services/ biorefinery-assistance-program

[10] Agricultural Act of 2014. Pub L No. 113-79, 128 Stat 649. February 4, 2014. https://www.govinfo.gov/content/ pkg/PLAW-113publ79/pdf/PLAW-

[11] Peterson S, Peck C, Stright D, Newes E, Inman D, Vimmerstedt L, et al. Overview of the Biomass Scenario Model. NREL/CP\_6A20- 60172. 2015. https://www.nrel.gov/

docs/fy15osti/60172.pdf

iseesystems.com

[12] Isee Systems. Lebanon, NH. Available from: https://www.

2014. Availabe from: http://

[13] Sterman J. Learning from evidence in a complex world. American Journal of Public Health. 2006;**96**(3):505-514

[14] U.S. Department of Agriculture, Economic Research Service. U.S. Farm Resource Regions. Retrieved from Agricultural Resource Management Survey (ARMS): Resource Regions.

webarchives.cdlib.org/wayback.public/ UERS\_ag\_1/20111128195215, http://

[1] Energy Tax Act of 1978 Public Law 95-618, 92 Stat. 3174. https://www. govinfo.gov/app/details/STATUTE-92/

Administration. Fuel Ethanol Overview, 1981-2012. 2014. https://www.eia.gov/

[3] U.S. Environmental Protection Agency. State Actions Banning MTBE (Statewide) (No. EPA420-B-04-009). 2004. https://nepis.epa.gov/Exe/ZyNET. exe/P1004KHN.TXT?ZyActionD=ZyDo cument&Client=EPA&Index=2000+Th ru+2005&Docs=&Query=&Time=&En dTime=&SearchMethod=1&TocRestric t=n&Toc=&TocEntry=&QField=&QFi eldYear=&QFieldMonth=&QFieldDay= &IntQFieldOp=0&ExtQFieldOp=0&X mlQuery=&File=D%3A%5Czyfiles%5C Index%20Data%5C00thru05%5CTxt% 5C00000021%5CP1004KHN.txt&User= ANONYMOUS&Password=anonymous &SortMethod=h%7C-&MaximumDocu ments=1&FuzzyDegree=0&ImageQuali ty=r75g8/r75g8/x150y150g16/i425&Disp lay=hpfr&DefSeekPage=x&SearchBack =ZyActionL&Back=ZyActionS&BackD esc=Results%20page&MaximumPages= 1&ZyEntry=1&SeekPage=x&ZyPURL

[4] Energy Policy Act of 2005. Public Law 109-58. https://www.govinfo.gov/

app/details/PLAW-109publ58

[5] U.S. Environmental Protection Agency. Gasoline|Methyl Tertiary Butyl Ether (MTBE)|US EPA [WWW Document]. 2013. Available from: http://www.epa.gov/mtbe/gas.htm

[6] H.R. 6 (110th). Energy Independence and Security Act of 2007. Pub L No. 110-140, 121 Stat 1492. 2007. https:// www.govinfo.gov/app/details/

STATUTE-92-Pg3174

**References**

petroleum/data.php

[2] U.S. Energy Information

*Insights from over 10 Years of Cellulosic Biofuel Modeling DOI: http://dx.doi.org/10.5772/intechopen.84874*

#### **References**

*Cellulose*

production.

in overall biofuel production.

**Author details**

and Steve Peterson2

Golden, Colorado, USA

Daniel Inman1

**12**

USA

provided the original work is properly cited.

\*, Emily Newes1

\*Address all correspondence to: daniel.inman@nrel.gov

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

, Brian Bush1

1 The Strategic Energy Analysis Center, National Renewable Energy Laboratory,

2 Thayer School of Engineering at Dartmouth College, Hanover, New Hampshire,

, Laura Vimmerstedt1

Our simulations suggest that it is beneficial for the feedstock supply system to transition away from short-distance (i.e., <50 miles) transport of bales and/or any other low-density formats, to a densified system modeled after the modern commodity grain system, using larger collection radii and centralized depots. Our simulations also suggest that the temporal component is substantial—earlier transition to a high density, commodity logistics system leads to the largest gains in cellulosic feedstock production and utilization—in our model, densified A scenario accelerates maturation of the feedstock supply 21. By the end of our simulation, the Densified A scenario results in ~15% greater feedstock

Industrial learning (learning by doing) is a key system lever in developing industries such as the biofuel/bioproducts industry. Because the industrial learning process follows a positive feedback loop, small perturbations have large system impacts. Shared learning amplifies the industrial learning process. Advances across similar industries are shared among the industries, resulting in a substantial positive impact on the industry. A potential extension would be to look at what percent of learning needs to be shared across similar technologies for a substantial increase

[1] Energy Tax Act of 1978 Public Law 95-618, 92 Stat. 3174. https://www. govinfo.gov/app/details/STATUTE-92/ STATUTE-92-Pg3174

[2] U.S. Energy Information Administration. Fuel Ethanol Overview, 1981-2012. 2014. https://www.eia.gov/ petroleum/data.php

[3] U.S. Environmental Protection Agency. State Actions Banning MTBE (Statewide) (No. EPA420-B-04-009). 2004. https://nepis.epa.gov/Exe/ZyNET. exe/P1004KHN.TXT?ZyActionD=ZyDo cument&Client=EPA&Index=2000+Th ru+2005&Docs=&Query=&Time=&En dTime=&SearchMethod=1&TocRestric t=n&Toc=&TocEntry=&QField=&QFi eldYear=&QFieldMonth=&QFieldDay= &IntQFieldOp=0&ExtQFieldOp=0&X mlQuery=&File=D%3A%5Czyfiles%5C Index%20Data%5C00thru05%5CTxt% 5C00000021%5CP1004KHN.txt&User= ANONYMOUS&Password=anonymous &SortMethod=h%7C-&MaximumDocu ments=1&FuzzyDegree=0&ImageQuali ty=r75g8/r75g8/x150y150g16/i425&Disp lay=hpfr&DefSeekPage=x&SearchBack =ZyActionL&Back=ZyActionS&BackD esc=Results%20page&MaximumPages= 1&ZyEntry=1&SeekPage=x&ZyPURL

[4] Energy Policy Act of 2005. Public Law 109-58. https://www.govinfo.gov/ app/details/PLAW-109publ58

[5] U.S. Environmental Protection Agency. Gasoline|Methyl Tertiary Butyl Ether (MTBE)|US EPA [WWW Document]. 2013. Available from: http://www.epa.gov/mtbe/gas.htm

[6] H.R. 6 (110th). Energy Independence and Security Act of 2007. Pub L No. 110-140, 121 Stat 1492. 2007. https:// www.govinfo.gov/app/details/ PLAW-110publ140

[7] Bacovsky D, Ludwiczek N, Ognissanto M, Worgetter M. Status of Advanced Biofuels Demonstration Facilities in 2012: A Report to IEA Bioenergy Task 39 (No. T39-P1b). International Energy Agency; 2013. http://task39.sites.olt.ubc.ca/ files/2013/12/2013\_Bacovsky\_Statusof-Advanced-Biofuels-Demonstration-Facilities-in-2012.pdf

[8] U.S. Department of Energy. Bioenergy Technologies Office Multi-Year Program Plan. 2013. http:// bioenergy.energy.gov/pdfs/mypp\_ may\_2013.pdf

[9] U.S. Department of Agriculture. Biorefinery Assistance Program [WWW document]. 2015. Available from: http://www. rd.usda.gov/programs-services/ biorefinery-assistance-program

[10] Agricultural Act of 2014. Pub L No. 113-79, 128 Stat 649. February 4, 2014. https://www.govinfo.gov/content/ pkg/PLAW-113publ79/pdf/PLAW-113publ79.pdf

[11] Peterson S, Peck C, Stright D, Newes E, Inman D, Vimmerstedt L, et al. Overview of the Biomass Scenario Model. NREL/CP\_6A20- 60172. 2015. https://www.nrel.gov/ docs/fy15osti/60172.pdf

[12] Isee Systems. Lebanon, NH. Available from: https://www. iseesystems.com

[13] Sterman J. Learning from evidence in a complex world. American Journal of Public Health. 2006;**96**(3):505-514

[14] U.S. Department of Agriculture, Economic Research Service. U.S. Farm Resource Regions. Retrieved from Agricultural Resource Management Survey (ARMS): Resource Regions. 2014. Availabe from: http:// webarchives.cdlib.org/wayback.public/ UERS\_ag\_1/20111128195215, http://

#### *Cellulose*

www.ers.usda.gov/Briefing/ARMS/ resourceregions/resourceregions. htm#new

[15] McDowell R. Learning by doing and spillovers in renewable energy [Ph.D. thesis]. Massachusetts Institute of Technology, Department of Economics; 2016

[16] Irwin DA, Klenow PJ. Learning-bydoing spillovers in the semiconductor industry. Journal of Political Economy. 1994;**105**(6):1200-1227

[17] Executive Order S-01-07. State of California, Office of the Governor. 2007. Available from: https://www.arb.ca.gov/ fuels/lcfs/eos0107.pdf

[18] Public Law 110-246-June 18, 2008. The Food, Conservation, and Energy Act of 2008. Available from: https:// www.agriculture.senate.gov/imo/ media/doc/pl110-246.pdf

**15**

**Chapter 2**

**Abstract**

Biorefinery

Alternative Raw Materials for

Pulp and Paper Production in

*María Eugenia Eugenio, David Ibarra,* 

*Isabel Bascón and Alejandro Rodríguez*

available alongside traditional products.

pulp, paper, biorefinery

**1. Introduction**

*Raquel Martín-Sampedro, Eduardo Espinosa,* 

the Concept of a Lignocellulosic

The main source of cellulosic fibre used for pulp and paper production comes from wood, while non-wood fibres are used to a lesser extent. However, a renewed interest exists in the use of non-woody raw materials due to their abundance as source of low-cost fibres and because they are sometimes the only exploitable source of fibres in certain geographical areas, mainly in developing countries. Moreover, the great variety of characteristics, fibre dimensions and chemical composition of these alternative raw materials give them a great potential to produce different types of papers. On the other hand, the pulp and paper industry is an excellent starting point for the development of lignocellulosic biorefineries, possessing the necessary technology and infrastructure as well as extensive experience in lignocellulosic biomass transformation. Since its beginnings, the pulp and paper industry has been practicing certain aspects of the biorefinery concept, generating the energy necessary for the production of cellulosic pulp from the combustion of lignocellulosic waste and black liquors, recovering the chemical reagents used and generating high value-added products (e.g. tall oil) together with cellulosic pulp. However, the evolution of the pulp and paper industry to a lignocellulosic biorefinery requires technological innovations to make bioenergy and new bioproducts

**Keywords:** alternative raw material, agricultural residues, annual plant (vegetables),

Several successful industrial factories based on alternative raw materials for pulp and paper production already exist nowadays [1, 2]. Lignocellulose is the major structural component of plants and is by far the most abundant type of earthly biomass [1, 3]. It mainly consists of cellulose (40–60%), hemicellulose (10–40%) and lignin (15–30%), with minor amounts of extractives, proteins and inorganic compounds [1, 3]. Lignocellulose components can be found in both woody (e.g.

#### **Chapter 2**

*Cellulose*

htm#new

2016

www.ers.usda.gov/Briefing/ARMS/ resourceregions/resourceregions.

[15] McDowell R. Learning by doing and spillovers in renewable energy [Ph.D. thesis]. Massachusetts Institute of Technology, Department of Economics;

[16] Irwin DA, Klenow PJ. Learning-bydoing spillovers in the semiconductor industry. Journal of Political Economy.

[17] Executive Order S-01-07. State of California, Office of the Governor. 2007. Available from: https://www.arb.ca.gov/

[18] Public Law 110-246-June 18, 2008. The Food, Conservation, and Energy Act of 2008. Available from: https:// www.agriculture.senate.gov/imo/

1994;**105**(6):1200-1227

fuels/lcfs/eos0107.pdf

media/doc/pl110-246.pdf

**14**

## Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic Biorefinery

*María Eugenia Eugenio, David Ibarra, Raquel Martín-Sampedro, Eduardo Espinosa, Isabel Bascón and Alejandro Rodríguez*

#### **Abstract**

The main source of cellulosic fibre used for pulp and paper production comes from wood, while non-wood fibres are used to a lesser extent. However, a renewed interest exists in the use of non-woody raw materials due to their abundance as source of low-cost fibres and because they are sometimes the only exploitable source of fibres in certain geographical areas, mainly in developing countries. Moreover, the great variety of characteristics, fibre dimensions and chemical composition of these alternative raw materials give them a great potential to produce different types of papers. On the other hand, the pulp and paper industry is an excellent starting point for the development of lignocellulosic biorefineries, possessing the necessary technology and infrastructure as well as extensive experience in lignocellulosic biomass transformation. Since its beginnings, the pulp and paper industry has been practicing certain aspects of the biorefinery concept, generating the energy necessary for the production of cellulosic pulp from the combustion of lignocellulosic waste and black liquors, recovering the chemical reagents used and generating high value-added products (e.g. tall oil) together with cellulosic pulp. However, the evolution of the pulp and paper industry to a lignocellulosic biorefinery requires technological innovations to make bioenergy and new bioproducts available alongside traditional products.

**Keywords:** alternative raw material, agricultural residues, annual plant (vegetables), pulp, paper, biorefinery

#### **1. Introduction**

Several successful industrial factories based on alternative raw materials for pulp and paper production already exist nowadays [1, 2]. Lignocellulose is the major structural component of plants and is by far the most abundant type of earthly biomass [1, 3]. It mainly consists of cellulose (40–60%), hemicellulose (10–40%) and lignin (15–30%), with minor amounts of extractives, proteins and inorganic compounds [1, 3]. Lignocellulose components can be found in both woody (e.g.

spruce, pine, eucalypt, poplar, etc.) and non-woody biomass, the latter including vegetables (e.g. bamboo, tagasaste, kenaf, abaca, etc.) and agriculture residues from harvesting and pruning operations (e.g. barley straw, wheat straw, orange tree pruning, olive tree pruning, etc.) and from agro-food industry [e.g. bagasse, empty fruit bunches from oil palm (EFB), etc.]. Cellulose is a linear and highly ordered polymer of cellobiose (D-glucopyranosyl β-1,4-D-glucopyranose), whereas hemicellulose represents a family of branched carbohydrate polymers containing both pentoses (e.g. xylose, arabinose) and hexoses (e.g. galactose, mannose, glucose) and showing often uronic acids (e.g. glucuronic acid) and acetyl moieties as sidechain groups [1, 3]. By contrast, lignin is a three-dimensional network buildup of dimethoxylated (syringyl, S), monomethoxylated (guaiacyl, G) and non-methoxylated (p-hydroxyphenyl, H) phenylpropanoid units, derived from the corresponding p-hydroxycinnamyl alcohols, which give rise to a variety of subunits including different ether and carbon–carbon bonds [4].

The main non-food use of lignocellulosic biomass is the production of cellulosic pulp from which a wide range of products can be obtained, highlighting the production of paper. At the beginning of the 1990s, there was the conviction that the arrival of new information technologies would reduce the consumption of paper; however the data of world consumption of paper and cardboard revoke this idea as it went from 240 million tonnes in 1990 to 413 million tonnes in 2016, of which 77.3 million tonnes are consumed in Europe [5]. In the past, the raw materials used in the manufacture of paper were herbaceous biomass such as flax, cotton, bamboo and cereal straw. It was not until the middle of the nineteenth century when woody materials began to be used, mainly due to the increased demand for paper because of the emergence and increased use of printing. Today, most of the cellulosic fibers used come from wood species, mainly hardwoods and softwoods [1, 2, 6]. Nevertheless, in recent years there has been an increase in consumer awareness of the need to preserve the environment, which is why they demand a more ecological production of paper, both in the use of raw materials and in manufacturing processes. With the same purpose, government bodies devote economic and human resources to research into alternative raw materials to conventional ones. For these reasons, a large number of studies on the use of non-woody materials, including agriculture residues and vegetables as alternative source for cellulosic pulp production, have emerged in recent years [1, 7–14].

Some of the advantages of using non-woody raw materials can be mentioned: (i) in developing countries with scarce forest resources, non-woody biomass provides an effective alternative to importing wood, paper, or cellulosic pulp. In these countries, there may be a large area devoted to food crops, which would provide considerable amounts of agricultural residues and agro-food industries [1, 15]; (ii) non-woody biomass increases the added value of agri-food crops by taking advantage of their residues (traditionally used for burning or agricultural amendments) to obtain a product in great demand such as paper [1, 15]; (iii) production of special papers, whose most suitable raw materials are certain vegetable alternatives to conventional woods [1, 16]; and (iv) since the morphological characteristics of the fibers and the chemical composition of the non-woody species are very varied, a wide range of papers can be obtained by properly selecting and/or mixing these raw materials [1, 14].

#### **2. Availability of raw materials**

The availability of raw materials is very important when approaching the industrial facility for the production of cellulosic pulp. Availability is related to

**17**

lignocellulosic materials.

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic…*

the production and location of the various lignocellulosic materials that can be used for the intended purpose. In the case of agricultural residues from harvesting and pruning operations, it can be said that they are very abundant in Spain. Specifically, it is estimated that the production of the most important agricultural residues, due to their abundance, such as cereal straw, sunflower stalks, vine shoots, cotton stems, olive, orange and peach tree pruning and vegetable and other similar crop wastes, represents about 50 million tonnes per year, with Andalusia

Due to its abundance, it seems that the most recommended agricultural residue for the manufacture of paper pulp is cereal straw since it represents almost 20% of the agricultural residues considered in 2007, and the technology used in its collection is fully developed [1, 17–19]. Regarding the waste from the agri-food industry used for the production of cellulosic pulp, the bagasse from the extraction of sugar cane and waste from the palm oil industry (EFB) should be highlighted [20].

With regard to alternative vegetables for cellulosic pulp production, they can be classified in three groups: (i) plants of wild nature such as bamboo, different types of cane, esparto grass, etc. [21]; (ii) plants from plantations with industrial uses, such as sorghum, abaca, sisal, jute, hemp, kenaf, flax, etc. [7, 22]; and (iii) other plants, mainly herbaceous species, grasses and legumes, which produce high biomass yields when grown in intensive plantations (tagasaste, *Leucaena* spp.,

The prolonged storage of lignocellulosic raw materials is always necessary in the pulp and paper industry. In the case of raw materials that are harvested only at a specific period of the year, the storage is even more important. Therefore, these raw materials must be collected in order to meet the annual needs of a factory, so that it operates all year round, with the consequent better use of installed capacity. On the other hand, many alternative lignocellulosic materials are more easily deteriorated due to their non-woody special properties, such as straws, herbaceous vegetables, etc., mainly if they contain high percentages of humidity. In fact, of all the factors that influence the storage of this type of sources, the most relevant is the residual humidity. Given that these materials do not require too rigorous conservation, as they are not intended for food, the rule of allowing slightly higher humidity than the "Caurie safety" humidity obtained by adjusting the experimental data on equilibrium humidity and relative humidity of the environment of the adsorption isotherms to the Caurie equation can generally be adapted. Applying this standard and observing the experimental adsorption isotherms, it appears that wheat straw, vine shoots and cotton stems can be well conserved in environments with relative humidity below 60–70%, while other agricultural residues such as olive tree pruning or sunflower stems require lower values [26]. On the other hand, it has been verified that the recommended maximum relative humidity values, according to the standard followed in this work, coincide with those obtained experimentally when storing the different agricultural residues considered in environments with different relative humidity for 10 or 12 months. As the chemical composition of these agricultural residues is considered as well as their fibrous structure does not differ so much from other agricultural residues such as wastes from agro-food industries, forestry residues and vegetable materials in general, the above conclusions can be extended to all these alternative

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

contributing with more than 20% [1, 17].

**3. Storage of lignocellulosic materials**

etc.) [23–25].

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

the production and location of the various lignocellulosic materials that can be used for the intended purpose. In the case of agricultural residues from harvesting and pruning operations, it can be said that they are very abundant in Spain. Specifically, it is estimated that the production of the most important agricultural residues, due to their abundance, such as cereal straw, sunflower stalks, vine shoots, cotton stems, olive, orange and peach tree pruning and vegetable and other similar crop wastes, represents about 50 million tonnes per year, with Andalusia contributing with more than 20% [1, 17].

Due to its abundance, it seems that the most recommended agricultural residue for the manufacture of paper pulp is cereal straw since it represents almost 20% of the agricultural residues considered in 2007, and the technology used in its collection is fully developed [1, 17–19]. Regarding the waste from the agri-food industry used for the production of cellulosic pulp, the bagasse from the extraction of sugar cane and waste from the palm oil industry (EFB) should be highlighted [20].

With regard to alternative vegetables for cellulosic pulp production, they can be classified in three groups: (i) plants of wild nature such as bamboo, different types of cane, esparto grass, etc. [21]; (ii) plants from plantations with industrial uses, such as sorghum, abaca, sisal, jute, hemp, kenaf, flax, etc. [7, 22]; and (iii) other plants, mainly herbaceous species, grasses and legumes, which produce high biomass yields when grown in intensive plantations (tagasaste, *Leucaena* spp., etc.) [23–25].

#### **3. Storage of lignocellulosic materials**

The prolonged storage of lignocellulosic raw materials is always necessary in the pulp and paper industry. In the case of raw materials that are harvested only at a specific period of the year, the storage is even more important. Therefore, these raw materials must be collected in order to meet the annual needs of a factory, so that it operates all year round, with the consequent better use of installed capacity. On the other hand, many alternative lignocellulosic materials are more easily deteriorated due to their non-woody special properties, such as straws, herbaceous vegetables, etc., mainly if they contain high percentages of humidity. In fact, of all the factors that influence the storage of this type of sources, the most relevant is the residual humidity. Given that these materials do not require too rigorous conservation, as they are not intended for food, the rule of allowing slightly higher humidity than the "Caurie safety" humidity obtained by adjusting the experimental data on equilibrium humidity and relative humidity of the environment of the adsorption isotherms to the Caurie equation can generally be adapted. Applying this standard and observing the experimental adsorption isotherms, it appears that wheat straw, vine shoots and cotton stems can be well conserved in environments with relative humidity below 60–70%, while other agricultural residues such as olive tree pruning or sunflower stems require lower values [26]. On the other hand, it has been verified that the recommended maximum relative humidity values, according to the standard followed in this work, coincide with those obtained experimentally when storing the different agricultural residues considered in environments with different relative humidity for 10 or 12 months. As the chemical composition of these agricultural residues is considered as well as their fibrous structure does not differ so much from other agricultural residues such as wastes from agro-food industries, forestry residues and vegetable materials in general, the above conclusions can be extended to all these alternative lignocellulosic materials.

*Cellulose*

spruce, pine, eucalypt, poplar, etc.) and non-woody biomass, the latter including vegetables (e.g. bamboo, tagasaste, kenaf, abaca, etc.) and agriculture residues from harvesting and pruning operations (e.g. barley straw, wheat straw, orange tree pruning, olive tree pruning, etc.) and from agro-food industry [e.g. bagasse, empty fruit bunches from oil palm (EFB), etc.]. Cellulose is a linear and highly ordered polymer of cellobiose (D-glucopyranosyl β-1,4-D-glucopyranose), whereas hemicellulose represents a family of branched carbohydrate polymers containing both pentoses (e.g. xylose, arabinose) and hexoses (e.g. galactose, mannose, glucose) and showing often uronic acids (e.g. glucuronic acid) and acetyl moieties as sidechain groups [1, 3]. By contrast, lignin is a three-dimensional network buildup of dimethoxylated (syringyl, S), monomethoxylated (guaiacyl, G) and non-methoxylated (p-hydroxyphenyl, H) phenylpropanoid units, derived from the corresponding p-hydroxycinnamyl alcohols, which give rise to a variety of subunits

The main non-food use of lignocellulosic biomass is the production of cellulosic pulp from which a wide range of products can be obtained, highlighting the production of paper. At the beginning of the 1990s, there was the conviction that the arrival of new information technologies would reduce the consumption of paper; however the data of world consumption of paper and cardboard revoke this idea as it went from 240 million tonnes in 1990 to 413 million tonnes in 2016, of which 77.3 million tonnes are consumed in Europe [5]. In the past, the raw materials used in the manufacture of paper were herbaceous biomass such as flax, cotton, bamboo and cereal straw. It was not until the middle of the nineteenth century when woody materials began to be used, mainly due to the increased demand for paper because of the emergence and increased use of printing. Today, most of the cellulosic fibers used come from wood species, mainly hardwoods and softwoods [1, 2, 6]. Nevertheless, in recent years there has been an increase in consumer awareness of the need to preserve the environment, which is why they demand a more ecological production of paper, both in the use of raw materials and in manufacturing processes. With the same purpose, government bodies devote economic and human resources to research into alternative raw materials to conventional ones. For these reasons, a large number of studies on the use of non-woody materials, including agriculture residues and vegetables as alternative source for cellulosic pulp produc-

Some of the advantages of using non-woody raw materials can be mentioned: (i) in developing countries with scarce forest resources, non-woody biomass provides an effective alternative to importing wood, paper, or cellulosic pulp. In these countries, there may be a large area devoted to food crops, which would provide considerable amounts of agricultural residues and agro-food industries [1, 15]; (ii) non-woody biomass increases the added value of agri-food crops by taking advantage of their residues (traditionally used for burning or agricultural amendments) to obtain a product in great demand such as paper [1, 15]; (iii) production of special papers, whose most suitable raw materials are certain vegetable alternatives to conventional woods [1, 16]; and (iv) since the morphological characteristics of the fibers and the chemical composition of the non-woody species are very varied, a wide range of papers can be obtained by

The availability of raw materials is very important when approaching the industrial facility for the production of cellulosic pulp. Availability is related to

including different ether and carbon–carbon bonds [4].

tion, have emerged in recent years [1, 7–14].

**2. Availability of raw materials**

properly selecting and/or mixing these raw materials [1, 14].

**16**

#### **4. Characterization of lignocellulosic materials**

Theoretically speaking any plant containing a reasonable amount of fibres can be used as a raw material for pulp and paper production. In practice, this is not the case. Besides the abundance of the plant, a steady supply and many other requirements are necessary. The fibre content of the plant is important. The plant contains in addition to fibres many non-fibrous cells, e.g. parenchyma cells. Fibres themselves vary much in different plants regarding their length, width, fine structures or microstructures, as well as their chemical composition. In one and the same plant, there are different types of fibres. The same fibre type is not equal in dimension but contains a spectrum of different dimensions. For this reason, one speaks of "average fibre length". The length of the fibre is one of the most important parameters affecting paper strength [1].

Chemical characterization, which gives rise to the percentages of the main chemical constituents of lignocellulosic materials (generally cellulose, hemicellulose, lignin, as well as extractives and ash), is of great interest since it can indicate their possible applications for obtaining cellulosic pulps, in terms of the most suitable process to follow and the type of pulp that can be obtained. In this characterization, the contents of holocellulose, lignin, α-cellulose, hemicellulose, and extractives in water, 1% soda and ethanol-benzene and ash are determined as the most important. For this chemical characterization, TAPPI test methods, including TAPPI T 204 om-88, TAPPI T 211 om-93, TAPPI T 222 om-88 [27], and NREL analytical methods (National Renewable Energy Laboratory NREL/TP-510-42168) are usually employed [28].

When comparing the results obtained by different authors, a good concordance is generally observed for each specific material. Sometimes discrepancies appear that can be attributed to the different procedures used as well as to the different origins and varieties of the raw materials considered. For example, the chemical characterization results obtained for rice straw were analysed and compared with (i) some agriculture residues from harvesting and pruning operations and from agro-food industry (e.g. olive tree pruning, wheat straw, sunflower stems, sorghum stems, bagasse, vine shoots, and cotton stems); (ii) some vegetables (e.g. *Leucaena colinsi*, *Leucaena leucocephala, Chamaecytisus proliferus*, *Retama monosperma*, *Phragmites* spp*.*, *Arundo donax, Prosopis juliflora*, and *Paulownia fortunei*); and (iii) softwoods (pine) and hardwoods (eucalyptus) [23, 29]. From this comparison it could be deduced that:


**19**

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic…*

• The holocellulose content of rice straw (60.7%) is similar to the value found for olive tree pruning and lower than the values found for the rest of the agricultural residues considered, as well as those of the alternative vegetables

• The content of α-cellulose of rice straw (41.2%) is lower than the values

presented by the cotton stems, *L. colinsi*, *L. leucocephala*, *C. proliferus*, *R. monosperma*, pine and eucalyptus; higher than the values corresponding to olive tree pruning, wheat straw, *Phragmites*, *P. fortunei*, *Prosopis juliflora*; and similar to

• The lignin content of rice straw (21.9%) is similar to the values corresponding to the cotton stems, *L. leucocephala* and *R. monosperma*; lower than the values found for *Phragmites* spp*.*, *A. donax*, *P. fortunei* and pine; and higher than those

In the same way, following the same example of rice straw, the experimental data on its physical characterization, which determines the size of its fibers, are compared with those of other lignocellulosic materials such as wheat straw, sunflower stalks, vine shoots, cotton tree stalks, olive tree pruning, sorghum stalks and pine and eucalyptus woods. After a biometric analysis with the rice straw studied, it is concluded that the length of its fibers (1.29 mm) is similar to that corresponding to the stems of sorghum, superior to those of the other agricultural residues consid-

In summary, it can be stated that the alternative non-woody materials under consideration have acceptable chemical and physical characteristics for the produc-

The manufacture of cellulosic pulp consists of the separation of cellulose fibers, which are cemented by the middle wall, composed mainly of lignin using physical or chemical methods [1, 2, 6]. In order to obtain cellulosic pulps from alternative non-woody materials, different chemical classical processes have been used (using chemical reagents such as soda, sodium sulphate and sodium sulfite) and organosolv (using organic solvents). In general, non-woody raw materials have a less density and more porous structure and, also in most of the cases, less lignin content, which means less energy and chemical requirements for fibre separation during pulp production. In addition, they have shorter growth cycles, reaching maturity faster than wood species, and in many cases the pulp yields

Soda pulping is the oldest pulping processes known and consists of subjecting raw materials, cut and conditioned, to a cooking process with a given concentration of sodium hydroxide, at a specific temperature and cooking time, depending on the quality of the pulp to be obtained (chemical or semi-chemical) and the characteristics of the raw materials used [1, 2, 6]. A recovery of reagents and purification of black liquors is finally carried out. Each of these sections of the process can group

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

considered and those of pine and eucalyptus.

the values of the other species considered.

ered and to that of eucalyptus but inferior to that of pine.

of the other species considered.

tion of pulp and paper [30].

obtained are higher [30].

*5.1.1 Soda pulping*

**5.1 Classical pulping processes**

**5. Cellulosic pulp production**

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*


In the same way, following the same example of rice straw, the experimental data on its physical characterization, which determines the size of its fibers, are compared with those of other lignocellulosic materials such as wheat straw, sunflower stalks, vine shoots, cotton tree stalks, olive tree pruning, sorghum stalks and pine and eucalyptus woods. After a biometric analysis with the rice straw studied, it is concluded that the length of its fibers (1.29 mm) is similar to that corresponding to the stems of sorghum, superior to those of the other agricultural residues considered and to that of eucalyptus but inferior to that of pine.

In summary, it can be stated that the alternative non-woody materials under consideration have acceptable chemical and physical characteristics for the production of pulp and paper [30].

#### **5. Cellulosic pulp production**

The manufacture of cellulosic pulp consists of the separation of cellulose fibers, which are cemented by the middle wall, composed mainly of lignin using physical or chemical methods [1, 2, 6]. In order to obtain cellulosic pulps from alternative non-woody materials, different chemical classical processes have been used (using chemical reagents such as soda, sodium sulphate and sodium sulfite) and organosolv (using organic solvents). In general, non-woody raw materials have a less density and more porous structure and, also in most of the cases, less lignin content, which means less energy and chemical requirements for fibre separation during pulp production. In addition, they have shorter growth cycles, reaching maturity faster than wood species, and in many cases the pulp yields obtained are higher [30].

#### **5.1 Classical pulping processes**

#### *5.1.1 Soda pulping*

Soda pulping is the oldest pulping processes known and consists of subjecting raw materials, cut and conditioned, to a cooking process with a given concentration of sodium hydroxide, at a specific temperature and cooking time, depending on the quality of the pulp to be obtained (chemical or semi-chemical) and the characteristics of the raw materials used [1, 2, 6]. A recovery of reagents and purification of black liquors is finally carried out. Each of these sections of the process can group

*Cellulose*

affecting paper strength [1].

are usually employed [28].

could be deduced that:

eucalyptus.

**4. Characterization of lignocellulosic materials**

Theoretically speaking any plant containing a reasonable amount of fibres can be used as a raw material for pulp and paper production. In practice, this is not the case. Besides the abundance of the plant, a steady supply and many other requirements are necessary. The fibre content of the plant is important. The plant contains in addition to fibres many non-fibrous cells, e.g. parenchyma cells. Fibres themselves vary much in different plants regarding their length, width, fine structures or microstructures, as well as their chemical composition. In one and the same plant, there are different types of fibres. The same fibre type is not equal in dimension but contains a spectrum of different dimensions. For this reason, one speaks of "average fibre length". The length of the fibre is one of the most important parameters

Chemical characterization, which gives rise to the percentages of the main chemical constituents of lignocellulosic materials (generally cellulose, hemicellulose, lignin, as well as extractives and ash), is of great interest since it can indicate their possible applications for obtaining cellulosic pulps, in terms of the most suitable process to follow and the type of pulp that can be obtained. In this characterization, the contents of holocellulose, lignin, α-cellulose, hemicellulose, and extractives in water, 1% soda and ethanol-benzene and ash are determined as the most important. For this chemical characterization, TAPPI test methods, including TAPPI T 204 om-88, TAPPI T 211 om-93, TAPPI T 222 om-88 [27], and NREL analytical methods (National Renewable Energy Laboratory NREL/TP-510-42168)

When comparing the results obtained by different authors, a good concordance is generally observed for each specific material. Sometimes discrepancies appear that can be attributed to the different procedures used as well as to the different origins and varieties of the raw materials considered. For example, the chemical characterization results obtained for rice straw were analysed and compared with (i) some agriculture residues from harvesting and pruning operations and from agro-food industry (e.g. olive tree pruning, wheat straw, sunflower stems, sorghum stems, bagasse, vine shoots, and cotton stems); (ii) some vegetables (e.g. *Leucaena colinsi*, *Leucaena leucocephala, Chamaecytisus proliferus*, *Retama monosperma*, *Phragmites* spp*.*, *Arundo donax, Prosopis juliflora*, and *Paulownia fortunei*); and (iii) softwoods (pine) and hardwoods (eucalyptus) [23, 29]. From this comparison it

• The value of the hot water soluble content of rice straw (7.3%) is lower than that of the rest of agricultural residues, except for bagasse and cotton stems; it is higher than the values found for the vegetables considered, except for *P.* 

• The value of soda extractives at 1% of rice straw (57.7%) is higher than the values corresponding to the rest of agricultural residues and vegetable consid-

• The content of ethanol-benzene extractives in rice straw (0.56%) is lower than that of the materials considered: agricultural and agro-food residues, veg-

• The ash content of rice straw (9.2%) is higher than the values presented by the rest of agricultural residues and much higher than the values of pine and

*fortunei*, and higher than the values for pine and eucalyptus.

ered, as well as those of pine and eucalyptus.

etables, pine and eucalyptus.

**18**

together different operations. Thus, for example, in the preparation of the raw material, a debarking is carried out in the case of woody plants or pith is removed in the case of some vegetables (e.g. sunflower stalks), a cutting or reduction in size to produce chips or flakes, a cleaning to remove impurities, and so on. In the pulping section, the operations of impregnation of the raw material, cooking or delignification to separate lignin, washing of the solid fraction resulting from cooking and draining of the same to eliminate the fluid used in the washing can be integrated. In the same way, the sections of reagents recovery and purification of residual black liquors are made up of different operations.

Soda pulps have been obtained from different alternative raw materials, specially agriculture residues such as wheat straw [31], sunflower stalks [32, 33], vine shoots [34], olive tree pruning [35], sorghum stalks [36, 37], tagasaste [24], EFB [20, 38], *H. funifera* [39] and rice straw [29, 38, 40], obtaining different yields depending on the conditions of soda concentration, temperature and cooking time used. Soda pulping has also been carried out using additives such as anthraquinone and parabenzoquinone, which accelerate the delignification process and stabilize carbohydrates, improving the yield of the process with respect to the conventional "soda" process when operated under the same working conditions. Assays have been carried out using wheat straw, olive tree pruning, rice straw and EFB. For rice straw and EFB, pulps have also been obtained using KOH in aqueous solutions [20, 40].

Miao et al. [22] also analysed the composition of the hemp root bast (HRT) to further subject it to a process of soda pulping and bleach it with an elemental chlorine free (ECF) bleaching sequence. These authors conclude that HRT is a suitable raw material to make paper obtaining a pulp with high viscosity and brightness (893 mL/g and 85.52% ISO, respectively). González et al. and Marrakchi et al. [41, 42] also applied soda pulping to orange tree wood and *Stipa tenacissima* stems, respectively. The first ones studied the influence of operational variables in both pulping and pulp beating (temperature, 155–185°C; time, 40–90 min; soda concentration, 10–16%; and number of PFI beating revolutions, 0 to 3000) on the yield and on the pulp refining degree as well as the physical properties of resulting paper sheets. These authors found an optimum compromise as regards operating conditions (170°C, 40 min, 13% soda concentration and 2700 number of PFI beating revolutions), obtaining a pulp with tensile index, burst index and tear index of around 59.11 Nm/g, 4.10 kN/g and 2.79 mNm<sup>2</sup> /g, respectively; these values deviate from their maximum values in 5.8, 2.2, and 1.4%, respectively. The pulp yield under these operating conditions is 43.9%; the refining degree is of 39.5°SR with the advantage of an increased drainability in paper production. These conditions involve a lower temperature, time, soda concentration and refining than those required to maximize the studied paper properties; so it is possible to save energy, chemicals and capital for industrial facilities. On the other hand, Marrakchi et al. [42] analysed the composition and fibre characteristics of the *S. tenacissima* steams and of its corresponding soda unbleached and bleached pulps. They conclude that the properties of *S. tenacissima* fibers are intermediate between those of non-wood and wood plants and are most often close to those of eucalyptus fibers. After studying a refining process and characterizing paper sheets obtained, these authors demonstrate the high potentiality of this non-wood species for papermaking applications.

#### *5.1.2 Kraft pulping*

The pulp obtained by this procedure is usually called Kraft (strong) if used for raw papers or "sulphate" if they are going to receive a further bleaching, although

**21**

*5.1.3 Sulfite pulping*

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic…*

both denominations are used indistinctly. The name "sulphate" is due to the fact that it is the sodium sulphate, and not the sodium sulphide, the reagent that is replaced, although the real agent that acts during the reaction is the sulphide that is generated in the recovery treatment of residual black liquors [1, 2, 6]. The process can be divided into two parts: the first is the obtaining of the pulp, and the second is

According to different authors [1, 2, 6], Kraft pulping process consists of the

i.The chips are taken to the reactor where they are cooked with white liquor (dissolution of sodium hydroxide and sodium sulphide), controlling the

ii.Pulping takes place during the established time, under appropriate pressure

iii.The black or residual liquor and the pulp are separated by filtration. The pulp is washed, and the black liquor is sent to the reagent recovery phase.

iv.Once washed, the pulp goes to the bleaching stage or to the raw paper

In the reagent recovery phase, organic compounds dissolved in black liquor are used to produce energy, thus reducing the rate of polluting effluents. The stages of recovery are as follows: (i) concentration of the black liquor in the evaporators; (ii) spraying of the concentrated black liquor in the oven, where the carbon reduces the sodium sulphate to sodium sulphide; (iii) the melted solids are discharged and dissolved in water, resulting in the green liquors; and (iv) the green liquor is sent to the causticizing stage, where the sodium carbonate reacts with the calcium oxide to

Some studies have been carried out to obtain Kraft pulps using alternative materials to traditional wood, including olive tree wood [43], *Cynara cardunculuns* L. [44], vine shoots [34], wheat straw [45] and kenaf [46]. Nevertheless, due to the more accessible structure of these materials compared to conventional wood materials, a soda process is usually applied to them, as this process is less pollutant. Thus, as an example, a factorial design of central composition experiments to find equations that relate the characteristics of the pulp and paper sheets with the operation variables have been realized using olive tree pruning [47, 48]. From these studies, it can be concluded that, in order to obtain pulp with suitable characteristics to be bleached to obtain paper and with good mechanical properties in the paper sheets, it is necessary to operate with an active alkali concentration of 25%, at 175°C during 90 min. The paper sheets obtained from olive tree pruning pulps were produced in different degrees of refining and were characterized attending their stretch index, burst index, and tear index. All paper sheets reach between 33 and 39 kN m/kg in the stretch index, between 1.5 and 2 kN/g in the burst index and 0.7–2.5 N m<sup>2</sup>

Sulfite pulps are obtained by cooking the lignocellulosic material with a solution of bisulfite and sulfur dioxide [1, 2, 6]. The cooking liquor is obtained by burning sulfur to obtain sulfur dioxide which is absorbed in a base of calcium, magnesium, sodium or ammonium. The most important variables of the "sulfite" process

tear index and not using a high refining degree (<45°SR) [47, 48].

/g in

the recovery of the chemical reagents used from black liquors.

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

following stages:

"liquid/solid" ratio.

manufacturing plant.

form sodium hydroxide [1, 2, 6].

conditions.

#### *Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

both denominations are used indistinctly. The name "sulphate" is due to the fact that it is the sodium sulphate, and not the sodium sulphide, the reagent that is replaced, although the real agent that acts during the reaction is the sulphide that is generated in the recovery treatment of residual black liquors [1, 2, 6]. The process can be divided into two parts: the first is the obtaining of the pulp, and the second is the recovery of the chemical reagents used from black liquors.

According to different authors [1, 2, 6], Kraft pulping process consists of the following stages:


In the reagent recovery phase, organic compounds dissolved in black liquor are used to produce energy, thus reducing the rate of polluting effluents. The stages of recovery are as follows: (i) concentration of the black liquor in the evaporators; (ii) spraying of the concentrated black liquor in the oven, where the carbon reduces the sodium sulphate to sodium sulphide; (iii) the melted solids are discharged and dissolved in water, resulting in the green liquors; and (iv) the green liquor is sent to the causticizing stage, where the sodium carbonate reacts with the calcium oxide to form sodium hydroxide [1, 2, 6].

Some studies have been carried out to obtain Kraft pulps using alternative materials to traditional wood, including olive tree wood [43], *Cynara cardunculuns* L. [44], vine shoots [34], wheat straw [45] and kenaf [46]. Nevertheless, due to the more accessible structure of these materials compared to conventional wood materials, a soda process is usually applied to them, as this process is less pollutant. Thus, as an example, a factorial design of central composition experiments to find equations that relate the characteristics of the pulp and paper sheets with the operation variables have been realized using olive tree pruning [47, 48]. From these studies, it can be concluded that, in order to obtain pulp with suitable characteristics to be bleached to obtain paper and with good mechanical properties in the paper sheets, it is necessary to operate with an active alkali concentration of 25%, at 175°C during 90 min. The paper sheets obtained from olive tree pruning pulps were produced in different degrees of refining and were characterized attending their stretch index, burst index, and tear index. All paper sheets reach between 33 and 39 kN m/kg in the stretch index, between 1.5 and 2 kN/g in the burst index and 0.7–2.5 N m<sup>2</sup> /g in tear index and not using a high refining degree (<45°SR) [47, 48].

#### *5.1.3 Sulfite pulping*

Sulfite pulps are obtained by cooking the lignocellulosic material with a solution of bisulfite and sulfur dioxide [1, 2, 6]. The cooking liquor is obtained by burning sulfur to obtain sulfur dioxide which is absorbed in a base of calcium, magnesium, sodium or ammonium. The most important variables of the "sulfite" process

*Cellulose*

solutions [20, 40].

together different operations. Thus, for example, in the preparation of the raw material, a debarking is carried out in the case of woody plants or pith is removed in the case of some vegetables (e.g. sunflower stalks), a cutting or reduction in size to produce chips or flakes, a cleaning to remove impurities, and so on. In the pulping section, the operations of impregnation of the raw material, cooking or delignification to separate lignin, washing of the solid fraction resulting from cooking and draining of the same to eliminate the fluid used in the washing can be integrated. In the same way, the sections of reagents recovery and purification of residual black

Soda pulps have been obtained from different alternative raw materials, specially agriculture residues such as wheat straw [31], sunflower stalks [32, 33], vine shoots [34], olive tree pruning [35], sorghum stalks [36, 37], tagasaste [24], EFB [20, 38], *H. funifera* [39] and rice straw [29, 38, 40], obtaining different yields depending on the conditions of soda concentration, temperature and cooking time used. Soda pulping has also been carried out using additives such as anthraquinone and parabenzoquinone, which accelerate the delignification process and stabilize carbohydrates, improving the yield of the process with respect to the conventional "soda" process when operated under the same working conditions. Assays have been carried out using wheat straw, olive tree pruning, rice straw and EFB. For rice straw and EFB, pulps have also been obtained using KOH in aqueous

Miao et al. [22] also analysed the composition of the hemp root bast (HRT) to further subject it to a process of soda pulping and bleach it with an elemental chlorine free (ECF) bleaching sequence. These authors conclude that HRT is a suitable raw material to make paper obtaining a pulp with high viscosity and brightness (893 mL/g and 85.52% ISO, respectively). González et al. and Marrakchi et al. [41, 42] also applied soda pulping to orange tree wood and *Stipa tenacissima* stems, respectively. The first ones studied the influence of operational variables in both pulping and pulp beating (temperature, 155–185°C; time, 40–90 min; soda concentration, 10–16%; and number of PFI beating revolutions, 0 to 3000) on the yield and on the pulp refining degree as well as the physical properties of resulting paper sheets. These authors found an optimum compromise as regards operating conditions (170°C, 40 min, 13% soda concentration and 2700 number of PFI beating revolutions), obtaining a pulp with tensile index, burst index and

values deviate from their maximum values in 5.8, 2.2, and 1.4%, respectively. The pulp yield under these operating conditions is 43.9%; the refining degree is of 39.5°SR with the advantage of an increased drainability in paper production. These conditions involve a lower temperature, time, soda concentration and refining than those required to maximize the studied paper properties; so it is possible to save energy, chemicals and capital for industrial facilities. On the other hand, Marrakchi et al. [42] analysed the composition and fibre characteristics of the *S. tenacissima* steams and of its corresponding soda unbleached and bleached pulps. They conclude that the properties of *S. tenacissima* fibers are intermediate between those of non-wood and wood plants and are most often close to those of eucalyptus fibers. After studying a refining process and characterizing paper sheets obtained, these authors demonstrate the high potentiality of this non-wood species for papermak-

The pulp obtained by this procedure is usually called Kraft (strong) if used for raw papers or "sulphate" if they are going to receive a further bleaching, although

/g, respectively; these

tear index of around 59.11 Nm/g, 4.10 kN/g and 2.79 mNm<sup>2</sup>

liquors are made up of different operations.

**20**

ing applications.

*5.1.2 Kraft pulping*

includes impregnation of the chips with the cooking reagents, dimensions and quality of the chips, temperature, time, pressure, pH of the white liquor, concentrations of sulfur dioxide combined (total and free), "liquid/solid" ratio and raw material used. Several "sulfite" processes have been proposed, including acid sulphite, bisulphite, alkaline sulphite, multistage sulphite, high-yield sulphite, etc., to obtain dissolving pulp [1, 2, 6]. In addition to these variables, it has been proposed to use molybdate or anthraquinone as catalysts, achieving a stabilization of the polysaccharides and an acceleration in delignification.

The sulfite process has been studied for several alternative raw materials but not as much as the soda and Kraft processes. Then, different studies of sulfite process with olive tree [35, 49], sunflower stalk [50], bagasse [51] and wheat straw [52] have been reported.

#### *5.1.4 Organosolv pulping*

These processes are characterized by the fact that the separation of lignin from lignocellulosic materials is achieved by solubilization with organic solvents, which are subsequently recovered for a new pulping cycle, resulting in a concentrate rich in lignin, from which different by-products can be obtained [53]. Among organic solvents used, alcohols (ethanol, methanol, butanol, etc.) and organic acids (acetic and formic acids) are commonly employed for non-woody materials [1, 2, 18, 24, 34, 54–66]. Nevertheless, acetone and other solvents such as phenol, formaldehyde, ethanolamine, ethylene glycol and ethanol-water have also been used for these alternative raw materials [1, 2, 19, 23, 34, 38, 60, 67–71], demonstrating that these materials can be used for the manufacture of pulp and paper through different processes with acceptable characteristics.

#### *5.1.4.1 Pulping using alcohols*

These are the most widely used processes due to the selectivity that these solvents contribute to the separation of the lignin and their easy recovery by distillation. In the case of the ethanol process, the influence of the operating variables (ethanol concentration, temperature, time and liquid/solid ratio) on the characteristics of the pulp and paper sheets obtained from different alternative raw materials, including olive tree [62], wheat straw [1, 2, 18], tagasaste [24, 57], sunflower stalk and *P. fortunei* [54, 55] and vine shoots [34], has been studied. As an example, in the case of wheat straw, when pulping is carried out at 200°C, with an ethanol concentration of 75% for 60 min, acceptable good values are obtained for yield (37.6%), holocellulose (88.8%), α-cellulose (46.9%) and lignin (7.2%) [1, 2, 18]. Methanol and butanol have also been used on wheat straw [37, 61].

#### *5.1.4.2 Pulping using organics acids*

Along with the processes that use alcohols, the processes that use organic acids are the following most used. The most common are those that use acetic acid and formic acid, and different studies have been reported with EFB [58], rice straw [63], jute [66], rapeseed straw [56], cardoon stalk [64], and wheat straw [65].

The pulping of wheat straw with acetic acid and formic acid has been carried out, studying the influence of operation variables on the properties of the resulting pulps. Comparing the results obtained when operating for times ranging between 0.5 and 2 h, at temperatures of 75–125°C and 150–200°C, and with concentrations of 50–100% and 50–80% of the formic and acetic acids, respectively, it is concluded

**23**

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic…*

that to obtain pulp with acceptable holocellulose (88.2%), α-cellulose (40.2%) and lignin (6.4%) contents are more effective than formic acid, operating at 50% concentration, 100°C and 2 h. This fact is mainly due to it requiring less acid and lower working temperature, with the consequent savings in chemical reagents and

Several studies have been studied with acetone solvent mainly on wheat straw [1, 2, 19, 60, 67]. From these studies it is concluded that it must be operated at 200°C, for 95–100 min and with 55–60% of acetone to obtain high holocellulose and α-cellulose values and low lignin and extractives, although the yield of the pulp is low [60]. To obtain good values of breaking length (3456 m), elongation

sheets formed, a temperature of 200°C has to be used. On the other hand, if the brightness has to be high, it has to be operated at 140°C for 1 h with a concentra-

The refining of pulp is an operation that modifies, through the action of mechanical work and in the presence of an aqueous medium, the morphology of the fibres and their physicochemical structure, decisively changing the properties of the paper sheets obtained from the refined pulp [1, 2, 6]. Using a Sprout-Bauer refiner, the influence of refining pulp from different agricultural residues (wheat straw, sunflower stems, vine shoots, olive tree pruning, cotton stems and sorghum stems) on the corresponding pulp and paper sheets was studied [1, 2, 19, 32, 69]. In view of the results, it can be concluded that olive tree pruning pulp must be severely refined to obtain good quality paper, although the maximum values of the ring crush test (RCT) and the tear index are reached for refining grades of 45 and 55°SR, respectively. In the case of EFB soda-anthraquinone pulp, a study has been carried out in a PFI refiner, studying the influence of the cooking variables (soda concentration, temperature and time) and the number of turns in the PFI on the properties of the resulting paper sheets [20]. From this study it is deduced that under some operation conditions, 15% of soda, 170°C, 70 min and 2,400 turns in the PFI, the properties of paper sheets obtained deviate less than 12% from their optimum values (59.6 Nm/g for the traction index, 4.48% for elongation, 4.17 kN/g

of 47.5°SR, acceptable for the formation of paper sheets. Under these conditions, reagents, energy and immobilized capital are saved with respect to the maximum

The bleaching of cellulosic pulps is carried out for the elimination and/or modification of some constituents that add color to the raw pulp, generally using chemical reagents in one or more stages and trying to degrade the cellulose fibers as little as possible [1, 2, 6]. The main light-absorbing substances in the pulps are lignin and resins, so in order to bleach a pulp, these substances must be chemically transformed into a solid state in order to reduce their light absorption characteristics or

/g) of the paper

/g for the tear index), for a degree of refining

(1.42%), burst index (1.36 KN/g) and tear index (3.86 mNm<sup>2</sup>

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

energy for heating [65].

*5.1.4.3 Acetone process*

tion of 60% acetone [65].

**6. Refining of cellulosic pulps**

for the burst index and 7.20 mNm2

**7. Bleaching of cellulosic pulps**

values of the operating variables used [20].

#### *Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

that to obtain pulp with acceptable holocellulose (88.2%), α-cellulose (40.2%) and lignin (6.4%) contents are more effective than formic acid, operating at 50% concentration, 100°C and 2 h. This fact is mainly due to it requiring less acid and lower working temperature, with the consequent savings in chemical reagents and energy for heating [65].

#### *5.1.4.3 Acetone process*

*Cellulose*

been reported.

*5.1.4 Organosolv pulping*

includes impregnation of the chips with the cooking reagents, dimensions and quality of the chips, temperature, time, pressure, pH of the white liquor, concentrations of sulfur dioxide combined (total and free), "liquid/solid" ratio and raw material used. Several "sulfite" processes have been proposed, including acid sulphite, bisulphite, alkaline sulphite, multistage sulphite, high-yield sulphite, etc., to obtain dissolving pulp [1, 2, 6]. In addition to these variables, it has been proposed to use molybdate or anthraquinone as catalysts, achieving a stabilization of the polysac-

The sulfite process has been studied for several alternative raw materials but not as much as the soda and Kraft processes. Then, different studies of sulfite process with olive tree [35, 49], sunflower stalk [50], bagasse [51] and wheat straw [52] have

These processes are characterized by the fact that the separation of lignin from lignocellulosic materials is achieved by solubilization with organic solvents, which are subsequently recovered for a new pulping cycle, resulting in a concentrate rich in lignin, from which different by-products can be obtained [53]. Among organic solvents used, alcohols (ethanol, methanol, butanol, etc.) and organic acids (acetic and formic acids) are commonly employed for non-woody materials [1, 2, 18, 24, 34, 54–66]. Nevertheless, acetone and other solvents such as phenol, formaldehyde, ethanolamine, ethylene glycol and ethanol-water have also been used for these alternative raw materials [1, 2, 19, 23, 34, 38, 60, 67–71], demonstrating that these materials can be used for the manufacture of pulp and paper through different

These are the most widely used processes due to the selectivity that these solvents contribute to the separation of the lignin and their easy recovery by distillation. In the case of the ethanol process, the influence of the operating variables (ethanol concentration, temperature, time and liquid/solid ratio) on the characteristics of the pulp and paper sheets obtained from different alternative raw materials, including olive tree [62], wheat straw [1, 2, 18], tagasaste [24, 57], sunflower stalk and *P. fortunei* [54, 55] and vine shoots [34], has been studied. As an example, in the case of wheat straw, when pulping is carried out at 200°C, with an ethanol concentration of 75% for 60 min, acceptable good values are obtained for yield (37.6%), holocellulose (88.8%), α-cellulose (46.9%) and lignin (7.2%) [1, 2, 18]. Methanol

Along with the processes that use alcohols, the processes that use organic acids are the following most used. The most common are those that use acetic acid and formic acid, and different studies have been reported with EFB [58], rice straw [63],

The pulping of wheat straw with acetic acid and formic acid has been carried out, studying the influence of operation variables on the properties of the resulting pulps. Comparing the results obtained when operating for times ranging between 0.5 and 2 h, at temperatures of 75–125°C and 150–200°C, and with concentrations of 50–100% and 50–80% of the formic and acetic acids, respectively, it is concluded

jute [66], rapeseed straw [56], cardoon stalk [64], and wheat straw [65].

charides and an acceleration in delignification.

processes with acceptable characteristics.

and butanol have also been used on wheat straw [37, 61].

*5.1.4.1 Pulping using alcohols*

*5.1.4.2 Pulping using organics acids*

**22**

Several studies have been studied with acetone solvent mainly on wheat straw [1, 2, 19, 60, 67]. From these studies it is concluded that it must be operated at 200°C, for 95–100 min and with 55–60% of acetone to obtain high holocellulose and α-cellulose values and low lignin and extractives, although the yield of the pulp is low [60]. To obtain good values of breaking length (3456 m), elongation (1.42%), burst index (1.36 KN/g) and tear index (3.86 mNm<sup>2</sup> /g) of the paper sheets formed, a temperature of 200°C has to be used. On the other hand, if the brightness has to be high, it has to be operated at 140°C for 1 h with a concentration of 60% acetone [65].

#### **6. Refining of cellulosic pulps**

The refining of pulp is an operation that modifies, through the action of mechanical work and in the presence of an aqueous medium, the morphology of the fibres and their physicochemical structure, decisively changing the properties of the paper sheets obtained from the refined pulp [1, 2, 6]. Using a Sprout-Bauer refiner, the influence of refining pulp from different agricultural residues (wheat straw, sunflower stems, vine shoots, olive tree pruning, cotton stems and sorghum stems) on the corresponding pulp and paper sheets was studied [1, 2, 19, 32, 69]. In view of the results, it can be concluded that olive tree pruning pulp must be severely refined to obtain good quality paper, although the maximum values of the ring crush test (RCT) and the tear index are reached for refining grades of 45 and 55°SR, respectively. In the case of EFB soda-anthraquinone pulp, a study has been carried out in a PFI refiner, studying the influence of the cooking variables (soda concentration, temperature and time) and the number of turns in the PFI on the properties of the resulting paper sheets [20]. From this study it is deduced that under some operation conditions, 15% of soda, 170°C, 70 min and 2,400 turns in the PFI, the properties of paper sheets obtained deviate less than 12% from their optimum values (59.6 Nm/g for the traction index, 4.48% for elongation, 4.17 kN/g for the burst index and 7.20 mNm2 /g for the tear index), for a degree of refining of 47.5°SR, acceptable for the formation of paper sheets. Under these conditions, reagents, energy and immobilized capital are saved with respect to the maximum values of the operating variables used [20].

#### **7. Bleaching of cellulosic pulps**

The bleaching of cellulosic pulps is carried out for the elimination and/or modification of some constituents that add color to the raw pulp, generally using chemical reagents in one or more stages and trying to degrade the cellulose fibers as little as possible [1, 2, 6]. The main light-absorbing substances in the pulps are lignin and resins, so in order to bleach a pulp, these substances must be chemically transformed into a solid state in order to reduce their light absorption characteristics or

be oxidized, reduced or hydrolysed, to make them soluble in aqueous solutions and thus be able to be removed from the pulps.

The need to reduce pollution from bleached pulp mills has led to the study of new bleaching sequences [1, 2, 6], with research focusing in three main directions: (i) bleaching processes with reagents without elemental chlorine (ECF), which consist of the total substitution of chlorinated stages by compounds such as chlorine dioxide (without elemental chlorine), regardless of whether other bleaching agents totally free of chlorine, such as oxygen, hydrogen peroxide, etc., are also used; (ii) bleaching processes with totally chlorine free reagents (TCF), using reagents such as oxygen, hydrogen peroxide and ozone, mainly [72]; and (iii) biological bleaching processes involving microorganisms or enzymes produced by them.

ECF and TCF bleaching processes including enzymatic stages have been studied for different alternative raw materials. It is worth highlighting the TCF processes which have been studied using different chemical reagents individually (hydrogen peroxide, oxygen, ozone, sodium perborate and peracetic acid) or with OZP bleaching sequences (where Z is an ozone stage) [1, 2, 6].

Hydrogen peroxide has been used for the bleaching of Kraft olive tree pruning pulp with a Kappa index of 21, operating at a temperature of 70°C and a consistency of 10%, and following a factorial design of experiments in which the peroxide concentration varies from 1 to 5% and the time from 30 to 210 min, finding that it is recommended to use a low-medium concentration of peroxide (1–3%) and a long time (210 min) [73]. Comparing the results with those of bleached pulps with other reagents, it is concluded that the viscosity of the pulps is higher in the case of peroxide bleached pulps than those bleached with oxygen, ozone or chlorine dioxide. To improve the Kappa index and brightness values of peroxide bleached pulp, it is desirable to combine hydrogen peroxide with oxygen or to use the combination oxygen and ozone [74].

For the bleaching of abaca soda pulp with peracetic acid [75], the influence of the operating conditions on the Kappa index, viscosity and brightness of the pulp and on the breaking length and burst index of the paper sheets was studied. Following a factorial design of experiments, it is concluded that operating at 55°C, with 4.5% peracetic acid for 150 min, a brightness of 79.9% is obtained (only 6.5% lower than the maximum possible) and the maximum possible values for the breaking length (6547 m), burst index (5.0 kN/g) and viscosity (1519 mL/g).

Peracetic acid has also been considered in the bleaching of olive tree pruning, finding that it has to be operated at 55°C for 90 min, a consistency of 10% and an acid concentration of 2.5%, providing good values for brightness and Kappa index and improving the viscosity of the bleached pulp with respect to crude pulp [76].

In the bleaching of abaca soda pulp with sodium perborate [77], the influence of the concentration of reagent (1–5%), temperature (60–80°C) and time (1–2 h) on the characteristics of the bleached pulp and the resulting paper sheets has been studied. It is concluded that in order to obtain pulp with the highest possible values of viscosity (1601 mL/g) and breaking length (5943 m), it is necessary to operate at 60°C, 1% perborate and 60 min, achieving a brightness of 62.7%, only 11.9% below the maximum possible.

For abaca soda pulp, the bleaching processes using hydrogen peroxide, peracetic acid, sodium perborate and the OZP sequence were compared from the point of view of pulp yield and brightness, breaking length and burst and tear indexes of the paper sheets. Overall, the best results are achieved for peracetic bleached pulp (4.5%, at 55°C for 0.5 h), providing little loss of yield (<1%) and some values for breaking length (6.555 m), burst index (4.97 kN/g) and tear index (15.77 mNm<sup>2</sup> /g), which only decrease, with respect to those of the raw starting pulps, by 7.0, 8.8 and 20.9%, respectively, while brightness (77.4%) increases by 56.7%; with the

**25**

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic…*

additional advantage that by operating at a lower temperature and for less time than in the other bleaching processes considered, energy savings are produced for heating and immobilized capital for industrial installations. The pulp bleached with the OZP sequence has more brightness but loses more yield. Moreover, the characteristics of the paper sheets are worse, and the process requires higher costs of reagent,

The OZP sequence has been applied to EFB soda-anthraquinone and diethanolamine pulps [79]. For similar Kappa index values for the two pulps (14.2 and 17.3), the paper sheets of the raw soda-anthraquinone pulp exhibit higher values for tensile (25.8 Nm/g), elongation (2.35%), burst index (1.69 kN/g) and tear index (0.50

/g) and brightness (60.6%) than the diethanolamine pulp, but the latter has

/g for the tear index and 71.3 vs. 77.5% for brightness [79].

It is worth highlighting in this section that apart from xylanases, the use of laccases has been used for the bleaching of alternative raw materials [80–84]. As it is known, these enzymes need a mediator to make the bleaching more effective since thanks to them they are able to oxidize not only the phenolic part but also the

The work of Camarero et al. [80], who apply three different fungal laccases (from *Pycnoporus cinnabarinus*, *Trametes versicolor* and *Pleurotus eryngii*) and two mediators, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1-hydroxybenzotriazole (HBT) to bleach flax pulp using a TCF sequence (enzymatic stage (L) plus hydrogen peroxide bleaching (P)), is noteworthy. These authors obtain delignification values of up to 90% after hydrogen peroxide bleaching when initial pulp is subjected to the enzymatic pretreatment (L). These results are improved when they apply a P stage under pressurized oxygen, obtaining a pulp with 82% ISO of brightness, and kappa index close to 1. Fillat et al. [81] also bleached flax pulp using natural mediators: syringaldehyde (SA), acetosyringone (AS) and p-coumaric acid (PCA) in combination with the laccase of *P. cinnabarinus* as a pretreatment prior to hydrogen peroxide bleaching stage. All mediators decrease the kappa index and increase the brightness of the bleached pulps after peroxide bleaching especially when SA was used. On the other hand, soda-anthraquinone pulp from orange tree pruning is also bleached by Fillat et al. [82]. In this case three different laccase-mediator systems (LMS) were used as pretreatment to an alkaline extraction plus a hydrogen peroxide bleaching: laccase from *Trametes villosa* (Tv), either in combination with 1-hydroxybenzotriazole (HBT) or with acetosyringone (AS) as natural mediator, and laccase from *Myceliophthora thermophila* (Mt) in combination with AS. The three laccase-mediator systems improve the bleaching sequence, with L-Tv + AS being the LMS that provides the highest delignification and improvement of optical properties. Finally, Martín-Sampedro et al. [83] also bleached soda pulp from olive tree pruning using not only a typical LMS but also adding xylanase jointly or prior to LMS to study the effect of this enzyme on the characteristics of the bleached pulps. The best results are found when both enzymes are applied in the same stage. In these conditions the lowest hydrogen peroxide consumption (63%), kappa index of 11.6 and brightness of 46% ISO are reached. Same authors [84] also bleached pulp from oil palm empty fruit bunches using laccase and xylanase. An enzymatic process with xylanase (X) and/or laccase (L) was incorporated before the alkaline extraction step

a higher viscosity (659 mL/g). When OZP bleaching sequence is used, the diethanolamine pulp exhibits higher viscosity (783 mL/g), and the properties of the paper sheets are similar to or better than those of the soda-anthraquinone pulp: 22.2 as opposed to 20.4 Nm/g for the tensile index, 1.30 vs. 1.42 kN/g for the burst index, 0.71

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

energy and immobilization [78].

mNm2

vs. 0.70 mNm2

**7.1 Biobleaching**

non-phenolic of the lignin.

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

additional advantage that by operating at a lower temperature and for less time than in the other bleaching processes considered, energy savings are produced for heating and immobilized capital for industrial installations. The pulp bleached with the OZP sequence has more brightness but loses more yield. Moreover, the characteristics of the paper sheets are worse, and the process requires higher costs of reagent, energy and immobilization [78].

The OZP sequence has been applied to EFB soda-anthraquinone and diethanolamine pulps [79]. For similar Kappa index values for the two pulps (14.2 and 17.3), the paper sheets of the raw soda-anthraquinone pulp exhibit higher values for tensile (25.8 Nm/g), elongation (2.35%), burst index (1.69 kN/g) and tear index (0.50 mNm2 /g) and brightness (60.6%) than the diethanolamine pulp, but the latter has a higher viscosity (659 mL/g). When OZP bleaching sequence is used, the diethanolamine pulp exhibits higher viscosity (783 mL/g), and the properties of the paper sheets are similar to or better than those of the soda-anthraquinone pulp: 22.2 as opposed to 20.4 Nm/g for the tensile index, 1.30 vs. 1.42 kN/g for the burst index, 0.71 vs. 0.70 mNm2 /g for the tear index and 71.3 vs. 77.5% for brightness [79].

#### **7.1 Biobleaching**

*Cellulose*

thus be able to be removed from the pulps.

be oxidized, reduced or hydrolysed, to make them soluble in aqueous solutions and

The need to reduce pollution from bleached pulp mills has led to the study of new bleaching sequences [1, 2, 6], with research focusing in three main directions: (i) bleaching processes with reagents without elemental chlorine (ECF), which consist of the total substitution of chlorinated stages by compounds such as chlorine dioxide (without elemental chlorine), regardless of whether other bleaching agents totally free of chlorine, such as oxygen, hydrogen peroxide, etc., are also used; (ii) bleaching processes with totally chlorine free reagents (TCF), using reagents such as oxygen, hydrogen peroxide and ozone, mainly [72]; and (iii) biological bleaching

ECF and TCF bleaching processes including enzymatic stages have been studied for different alternative raw materials. It is worth highlighting the TCF processes which have been studied using different chemical reagents individually (hydrogen peroxide, oxygen, ozone, sodium perborate and peracetic acid) or with OZP bleach-

Hydrogen peroxide has been used for the bleaching of Kraft olive tree pruning pulp with a Kappa index of 21, operating at a temperature of 70°C and a consistency of 10%, and following a factorial design of experiments in which the peroxide concentration varies from 1 to 5% and the time from 30 to 210 min, finding that it is recommended to use a low-medium concentration of peroxide (1–3%) and a long time (210 min) [73]. Comparing the results with those of bleached pulps with other reagents, it is concluded that the viscosity of the pulps is higher in the case of peroxide bleached pulps than those bleached with oxygen, ozone or chlorine dioxide. To improve the Kappa index and brightness values of peroxide bleached pulp, it is desirable to combine hydrogen peroxide with oxygen or to use the combination

For the bleaching of abaca soda pulp with peracetic acid [75], the influence of the operating conditions on the Kappa index, viscosity and brightness of the pulp and on the breaking length and burst index of the paper sheets was studied. Following a factorial design of experiments, it is concluded that operating at 55°C, with 4.5% peracetic acid for 150 min, a brightness of 79.9% is obtained (only 6.5% lower than the maximum possible) and the maximum possible values for the break-

Peracetic acid has also been considered in the bleaching of olive tree pruning, finding that it has to be operated at 55°C for 90 min, a consistency of 10% and an acid concentration of 2.5%, providing good values for brightness and Kappa index and improving the viscosity of the bleached pulp with respect to crude pulp [76]. In the bleaching of abaca soda pulp with sodium perborate [77], the influence of the concentration of reagent (1–5%), temperature (60–80°C) and time (1–2 h) on the characteristics of the bleached pulp and the resulting paper sheets has been studied. It is concluded that in order to obtain pulp with the highest possible values of viscosity (1601 mL/g) and breaking length (5943 m), it is necessary to operate at 60°C, 1% perborate and 60 min, achieving a brightness of 62.7%, only 11.9% below

For abaca soda pulp, the bleaching processes using hydrogen peroxide, peracetic acid, sodium perborate and the OZP sequence were compared from the point of view of pulp yield and brightness, breaking length and burst and tear indexes of the paper sheets. Overall, the best results are achieved for peracetic bleached pulp (4.5%, at 55°C for 0.5 h), providing little loss of yield (<1%) and some values for breaking length (6.555 m), burst index (4.97 kN/g) and tear index (15.77 mNm<sup>2</sup>

which only decrease, with respect to those of the raw starting pulps, by 7.0, 8.8 and 20.9%, respectively, while brightness (77.4%) increases by 56.7%; with the

/g),

ing length (6547 m), burst index (5.0 kN/g) and viscosity (1519 mL/g).

processes involving microorganisms or enzymes produced by them.

ing sequences (where Z is an ozone stage) [1, 2, 6].

oxygen and ozone [74].

the maximum possible.

**24**

It is worth highlighting in this section that apart from xylanases, the use of laccases has been used for the bleaching of alternative raw materials [80–84]. As it is known, these enzymes need a mediator to make the bleaching more effective since thanks to them they are able to oxidize not only the phenolic part but also the non-phenolic of the lignin.

The work of Camarero et al. [80], who apply three different fungal laccases (from *Pycnoporus cinnabarinus*, *Trametes versicolor* and *Pleurotus eryngii*) and two mediators, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1-hydroxybenzotriazole (HBT) to bleach flax pulp using a TCF sequence (enzymatic stage (L) plus hydrogen peroxide bleaching (P)), is noteworthy. These authors obtain delignification values of up to 90% after hydrogen peroxide bleaching when initial pulp is subjected to the enzymatic pretreatment (L). These results are improved when they apply a P stage under pressurized oxygen, obtaining a pulp with 82% ISO of brightness, and kappa index close to 1. Fillat et al. [81] also bleached flax pulp using natural mediators: syringaldehyde (SA), acetosyringone (AS) and p-coumaric acid (PCA) in combination with the laccase of *P. cinnabarinus* as a pretreatment prior to hydrogen peroxide bleaching stage. All mediators decrease the kappa index and increase the brightness of the bleached pulps after peroxide bleaching especially when SA was used. On the other hand, soda-anthraquinone pulp from orange tree pruning is also bleached by Fillat et al. [82]. In this case three different laccase-mediator systems (LMS) were used as pretreatment to an alkaline extraction plus a hydrogen peroxide bleaching: laccase from *Trametes villosa* (Tv), either in combination with 1-hydroxybenzotriazole (HBT) or with acetosyringone (AS) as natural mediator, and laccase from *Myceliophthora thermophila* (Mt) in combination with AS. The three laccase-mediator systems improve the bleaching sequence, with L-Tv + AS being the LMS that provides the highest delignification and improvement of optical properties. Finally, Martín-Sampedro et al. [83] also bleached soda pulp from olive tree pruning using not only a typical LMS but also adding xylanase jointly or prior to LMS to study the effect of this enzyme on the characteristics of the bleached pulps. The best results are found when both enzymes are applied in the same stage. In these conditions the lowest hydrogen peroxide consumption (63%), kappa index of 11.6 and brightness of 46% ISO are reached. Same authors [84] also bleached pulp from oil palm empty fruit bunches using laccase and xylanase. An enzymatic process with xylanase (X) and/or laccase (L) was incorporated before the alkaline extraction step

#### *Cellulose*

(E) and the hydrogen peroxide bleaching (P). Comparing with controls, the LEP sequence results in an improvement of optical properties (colorimetric properties and brightness) and a reduction of the kappa index. When both enzymes (xylanase and laccase) are used jointly, no improvement is detected; however, when the xylanase stage is applied before the laccase stage, the beneficial effects of laccase are boosted. Thus, the XLEP bleached pulp shows a brightness of 60.5% ISO, a kappa index of 5.4 although the hydrogen peroxide consumption increase (77.0 vs. 64.5% and 73.8% for EP and LEP, respectively).

#### **8. Integration of the pulp and paper industry using alternative raw materials into the biorefinery concept**

The concept of lignocellulosic biorefinery aims at the integral use of the main components of lignocellulosic raw materials to obtain energy, chemicals and products [85]. The pulp and paper industry is an excellent initial point for the establishment of this concept as it has the best infrastructure for biomass fractionation and conversion and a great deal of practical industrial experience. Then, the classical pulp and paper industry, including Kraft, sulfite and soda technologies, has been applying this concept for a long time as it not only produces paper as the main product (cellulosic fraction) but also recovers the reagents and produces energy from the residual black liquors (lignin-rich fraction) as well as the generation of bioproducts such as tall oils, which are sold to obtain high added value products (e.g. adhesives, detergents, etc.), and lignin for the production of chemicals or materials. In the future, the extraction of hemicelluloses prior to pulping will be included in order to make maximum use of lignocellulosic materials. A general scheme, which will be developed below including also gasification of lignin, is shown in **Figure 1**.

Using the same scheme-work of the pulp and paper industry with classical pulping methods, different organosolv pulping processes have been developed to produce cellulosic pulp and other products from different alternative raw materials such as agriculture residues [53], among them, those employing ethanol such as the Alcell© process for the production of cellulosic pulp, giving value to other biomass fractions, such as high-quality lignin in the residual black liquor with several potential industrial applications, and the Lignol© process, which also extracts lignin, as well as sugars for the production of ethanol, oligomers, furfural and acetic acid. However, one of the disadvantages of these processes lies in the incorporation of both extracts and a part of the hemicelluloses to the residual black liquors. For this reason, the possibility of carrying out a hydrolysis pretreatment of the polysaccharides with the original raw materials prior to organosolv pulping methods, using water at a high temperature (hydrothermal treatment), has been explored [53]. Then, a hydrolysis of the acetyl groups to acetic acid is produced, which acts as a catalyst solubilizing all or part of the hemicelluloses (autohydrolysis) and then resulting in a pretreatment aqueous fraction with oligomers (mainly glucooligosacharides and xylo-oligosacharides), sugars (glucose, xylose, arabinose), acetic, furfural or 5-hydroxymethyl-2-furfural (HMF) and some lignin. Oligomers are used as food additives or substrate for sugars, after hydrolysis and fermentation (xylose and arabinose could be fermented to ethanol or xylitol); and furfural and lignin derivatives have applications in the chemical industry [86, 87]. The disadvantage of this fractionation is the low selectivity towards cellulose, giving rise to a solid fraction structurally affected, which can limit its later use; but an adequate hydrothermal pretreatment achieves a solid fraction that can be used to obtain pulp and paper by classical or organosolv procedures, whose resistance can be improved using a relevant refining.

**27**

**Figure 1.**

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic…*

In the pulping processes of the solid fraction coming from autohydrolysis or hydrothermal pretreatment, some residual black liquors are obtained, with lignin being the majority component. These liquors, after the separation of water and/or organic solvents used in cooking (which are recycled in the cooking process), are transformed into a concentrate rich in lignin. From these concentrates lignin can be obtained for different uses, and/or it can be subjected to gasification processes with the aim of obtaining high-quality products such as hydrogen, methanol, synthesis

*Scheme of integration of pulp and paper industry into the biorefinery concept in the future.*

As commented above, one of the possibilities to convert the classical chemical pulp and paper industry into a biorefinery is to extract a portion of hemicelluloses from lignocellulosic materials prior to pulping, obtaining a liquid fraction enriched in hemicellulosic carbohydrates that can be converted into ethanol and/or chemical products. One of the options for the separation of hemicellulose from lignocellulosic materials is its depolymerization by autohydrolysis, also known as hydrothermal process, which does not require the addition of acids as it is auto-generated in the process [53, 85]. In addition to the process of autohydrolysis itself, the process of steam explosion is very significant (once autohydrolysis has taken place, the mixture undergoes a sudden decompression to produce the vaporization of the water contained in the fibers and the consequent disaggregation of the lignocellulosic matrix), as well as its variants, such as the Rash, Masonite, Iotech, Siropulper and Stake processes [53, 85]. These hydrothermal treatments can be carried out in a very wide range of operating conditions, with the temperature, time, solid concentration and particle size of lignocellulosic materials being the most influential variables [85]. In the case of autohydrolysis, the range of temperatures to treat lignocellulosic materials in an aqueous medium is in the range between 150 and 250°C. Under these conditions, the self-ionization of water generates protons that act as a catalyst for the hydrolysis

gas or dimethyl ether (DME) for motor applications [86–89].

**8.1 Hemicellulose isolation by hydrothermal treatments**

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

**Figure 1.**

*Cellulose*

and 73.8% for EP and LEP, respectively).

**materials into the biorefinery concept**

(E) and the hydrogen peroxide bleaching (P). Comparing with controls, the LEP sequence results in an improvement of optical properties (colorimetric properties and brightness) and a reduction of the kappa index. When both enzymes (xylanase and laccase) are used jointly, no improvement is detected; however, when the xylanase stage is applied before the laccase stage, the beneficial effects of laccase are boosted. Thus, the XLEP bleached pulp shows a brightness of 60.5% ISO, a kappa index of 5.4 although the hydrogen peroxide consumption increase (77.0 vs. 64.5%

**8. Integration of the pulp and paper industry using alternative raw** 

The concept of lignocellulosic biorefinery aims at the integral use of the main components of lignocellulosic raw materials to obtain energy, chemicals and products [85]. The pulp and paper industry is an excellent initial point for the establishment of this concept as it has the best infrastructure for biomass fractionation and conversion and a great deal of practical industrial experience. Then, the classical pulp and paper industry, including Kraft, sulfite and soda technologies, has been applying this concept for a long time as it not only produces paper as the main product (cellulosic fraction) but also recovers the reagents and produces energy from the residual black liquors (lignin-rich fraction) as well as the generation of bioproducts such as tall oils, which are sold to obtain high added value products (e.g. adhesives, detergents, etc.), and lignin for the production of chemicals or materials. In the future, the extraction of hemicelluloses prior to pulping will be included in order to make maximum use of lignocellulosic materials. A general scheme, which will be developed below including also gasification of lignin, is shown in **Figure 1**. Using the same scheme-work of the pulp and paper industry with classical pulping methods, different organosolv pulping processes have been developed to produce cellulosic pulp and other products from different alternative raw materials such as agriculture residues [53], among them, those employing ethanol such as the Alcell© process for the production of cellulosic pulp, giving value to other biomass fractions, such as high-quality lignin in the residual black liquor with several potential industrial applications, and the Lignol© process, which also extracts lignin, as well as sugars for the production of ethanol, oligomers, furfural and acetic acid. However, one of the disadvantages of these processes lies in the incorporation of both extracts and a part of the hemicelluloses to the residual black liquors. For this reason, the possibility of carrying out a hydrolysis pretreatment of the polysaccharides with the original raw materials prior to organosolv pulping methods, using water at a high temperature (hydrothermal treatment), has been explored [53]. Then, a hydrolysis of the acetyl groups to acetic acid is produced, which acts as a catalyst solubilizing all or part of the hemicelluloses (autohydrolysis) and then resulting in a pretreatment aqueous fraction with oligomers (mainly glucooligosacharides and xylo-oligosacharides), sugars (glucose, xylose, arabinose), acetic, furfural or 5-hydroxymethyl-2-furfural (HMF) and some lignin. Oligomers are used as food additives or substrate for sugars, after hydrolysis and fermentation (xylose and arabinose could be fermented to ethanol or xylitol); and furfural and lignin derivatives have applications in the chemical industry [86, 87]. The disadvantage of this fractionation is the low selectivity towards cellulose, giving rise to a solid fraction structurally affected, which can limit its later use; but an adequate hydrothermal pretreatment achieves a solid fraction that can be used to obtain pulp and paper by classical or organosolv procedures, whose resistance can be improved

**26**

using a relevant refining.

*Scheme of integration of pulp and paper industry into the biorefinery concept in the future.*

In the pulping processes of the solid fraction coming from autohydrolysis or hydrothermal pretreatment, some residual black liquors are obtained, with lignin being the majority component. These liquors, after the separation of water and/or organic solvents used in cooking (which are recycled in the cooking process), are transformed into a concentrate rich in lignin. From these concentrates lignin can be obtained for different uses, and/or it can be subjected to gasification processes with the aim of obtaining high-quality products such as hydrogen, methanol, synthesis gas or dimethyl ether (DME) for motor applications [86–89].

#### **8.1 Hemicellulose isolation by hydrothermal treatments**

As commented above, one of the possibilities to convert the classical chemical pulp and paper industry into a biorefinery is to extract a portion of hemicelluloses from lignocellulosic materials prior to pulping, obtaining a liquid fraction enriched in hemicellulosic carbohydrates that can be converted into ethanol and/or chemical products. One of the options for the separation of hemicellulose from lignocellulosic materials is its depolymerization by autohydrolysis, also known as hydrothermal process, which does not require the addition of acids as it is auto-generated in the process [53, 85]. In addition to the process of autohydrolysis itself, the process of steam explosion is very significant (once autohydrolysis has taken place, the mixture undergoes a sudden decompression to produce the vaporization of the water contained in the fibers and the consequent disaggregation of the lignocellulosic matrix), as well as its variants, such as the Rash, Masonite, Iotech, Siropulper and Stake processes [53, 85].

These hydrothermal treatments can be carried out in a very wide range of operating conditions, with the temperature, time, solid concentration and particle size of lignocellulosic materials being the most influential variables [85]. In the case of autohydrolysis, the range of temperatures to treat lignocellulosic materials in an aqueous medium is in the range between 150 and 250°C. Under these conditions, the self-ionization of water generates protons that act as a catalyst for the hydrolysis of the hemicellulose, reacting among others the acetyl groups (present in the form of esters in the hemicellulosic heteropolymers), which are released in the form of acetic acid. Its contribution to the generation of protons is 1700 to 1,000,000 times greater than that of water, so the contribution of aqueous protons to the hydrothermal process can be neglected once acetic acid has been generated. At the same time, there is total or partial solubilization of hemicelluloses and their conversion with good yields of oligosaccharides and monosaccharides, which can be used for different purposes [53, 85].

Other minor reactions associated with this type of process are the formation of products such as furfural from pentoses and HMF from hexoses; the generation of carbon dioxide by decomposition of carboxyl groups present in uronic acids; the condensation of some unstable molecules that intervene as reaction intermediates; the decomposition under severe conditions of products such as furfural, sensitive to acid concentration; the decomposition of HMF to formic and levulinic acids; and condensation reactions with lignin [90].

Different studies with traditional woody materials such as eucalypt have shown a pre-extraction of hemicellulose prior to pulping process by hydrothermal processes [91–93]. In the same way, these hydrothermal processes have also been applied to alternative raw materials such as paulownia [55], sunflower stems [54], rice straw [71], tagasaste [25] and *H. funifera* [94].

The influence of the temperature (160–200°C) of the autohydrolysis process applied to paulownia on the composition of the resulting solid and liquid fractions has been studied [55]. It is found that the maximum concentrations of glucose, xylose, arabinose, acetic acid, furfural, HMF and oligomers of the resulting liquid fraction correspond to when operating at maximum temperature.

A similar study carried out with sunflower stems concludes that at 190°C the highest values are obtained for the glucose, xylose and arabinose contents of the liquid fraction of the hydrothermal treatment, with a yield of 24.5%, while the yield of the solid fraction, which can be pulping, is 72.5% [54].

In the case of rice straw, the influence of temperature (150–190°C), time (0 to 20 min after reaching the working temperature) and liquid/solid ratio (6:10) on the hydrothermal treatment, on the lignin content, on the yield of the resulting solid fraction and on the composition of the corresponding liquid phase (glucose, xylose, arabinose and acetic acid) was studied [71]. It follows that in order to obtain high values of glucose (1.92 g/L), xylose (3.97 g/L), arabinose (0.99 g/L) and acetic acid (1.96 g/L) concentrations, it is necessary to operate at high temperature (190°C) and low-medium conditions for time (15 min) and hydromodule (9), which allows capital savings by not operating with the maximum time and using the maximum hydromodule value. The yield obtained for the solid fraction is 88.1%, and the lignin content is 24.43%.

Finally, tagasaste wood was submitted to hydrothermal treatment at 175–185°C [25]. Then, a liquor containing a substantially increased amount of oligomers (between 16.6 and 47.7% as percentages with respect to the content of the raw material in each polymer fraction) is obtained. In the case of *H. funifera*, a sulphuric acid-catalysed hydrothermal treatment (170°C, 0, 20 min after reaching operating temperature, 8 liquid/solid ratio, and 0.3% sulphuric acid), gives a liquid fraction containing 4.62% of glucose, 10.56% of xylose, 1.28% of arabinose, and a solid fraction with a solid yield of 57.0%.

#### **8.2 Pulping of the solid fraction from hydrothermal treatment**

Hydrothermal treatments under relatively mild operating conditions (temperature and time) do not cause significant alterations in the cellulose. In this way, solid fractions susceptible to delignification or pulping are obtained [53].

**29**

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic…*

The solid fraction of the hydrothermal treatment of paulownia carried out at 190°C was subjected to pulping process with ethanol following a factorial design of experiments [55]. The conclusion of this work is that operating at 180°C for 30 min and an ethanol concentration of 20%, obtained pulp has acceptable values of Kappa index and viscosity, and their corresponding paper sheets have a brightness of

In the case of sunflower stems [54], the solid fraction of a treatment carried out at 180°C is cooked with ethanol (70%, 170°C for 2 h and a hydromodule of 8) giving rise to a pulp with properties (36.3% of pulp yield, 69.1% cellulose, 12.6% hemicellulose, 18.2% lignin, 551 mL/g viscosity, 3.8 km breaking length, 1.23% elongation,

The influence of operating conditions (temperature from 160 to 180°C, time from 30 to 90 min and concentration of diethanolamine from 60 to 80%) on the pulping process of the solid fraction obtained from a hydrothermal treatment of rice straw (carried out at 190°C) on the characteristics of the pulp (yield, Kappa index, viscosity and degree of refining) and of the paper sheets obtained from them (length of rupture, elongation, burst index, tear index and brightness) was also studied [71]. It is deduced that it is convenient to operate at 162.5°C, 60 min and 70% of diethanolamine, since paper sheets present characteristics that deviate little from the optimal ones (less than 8% in the worst case), saving chemical reagents, energy for heating and immobilized capital for the installation, when operating with values of time and the concentration of diethanolamine medium and medium-low temperature, with respect to the maximums considered; likewise the values found for the yield and Kappa index deviate less than 14% with respect to

Autohydrolysed tagasaste wood was also submitted to ethanol and soda pulping procedures [25]. The autohydrolysis prior to ethanol pulping increases yields (53–60%); reduces Kappa index (28.8–34.6), but also viscosity (755–857 mL/g); and decreases paper strength (2.97–5.22 kNm/kg). However, applying a refining process to tagasaste pulp is found to improve its strength-related properties more markedly than in soda pulp from the same material (tensile index of 44 kNm/kg). In the case of *H. funifera*, the samples pretreated with sulphuric acid-catalysed autohydrolysis was subsequently submitted to soda, soda-anthraquinone, ethanolamine, ethylene glycol, diethanolamine and diethyleneglycol [94]. In this case, the best pulp of *H. funifera* pulp is obtained by cooking with 10% NaOH and 1% anthraquinone at 155°C for 30 min, exhibiting good values of yield (48.3%), viscosity (737 mL/g), Kappa index (15.2), tensile index (83.6 Nm/g), stretch (3.8%), burst index (7.34

raw material have better properties than the pulps from solid fraction of hydrother-

The valorization of lignin-rich black liquors generated from pulping processes is another transition path from the traditional pulp and paper industry to future biorefineries. Generally, residual lignins from black liquors are used to obtain energy for processing plants, mainly by combustion. However, the aromatic structure of lignin makes it a potential source for the production of new bio-based high-value products and chemicals, increasing the sustainability and competitiveness of this pulp and paper industry [86]. Other different fractions of lignin and compounds such as various polysaccharides present in these black liquors, which may not have

**8.3 Use of residual liquors components obtained during pulping**

/g and a tear

/g tear index) similar to that obtained by the

/g). Moreover, the soda-anthraquinone pulps of

27.4% ISO, a tensile index of 28.87 Nm/g, a burst index of 1.22 kPam2

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

/g.

1.15 kN/g burst index and 2.04 mNm<sup>2</sup>

index of 1.23 kNm<sup>2</sup>

soda process.

the optimal values.

mal treatments.

kN/g) and tear index (3.20 mNm<sup>2</sup>

#### *Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

The solid fraction of the hydrothermal treatment of paulownia carried out at 190°C was subjected to pulping process with ethanol following a factorial design of experiments [55]. The conclusion of this work is that operating at 180°C for 30 min and an ethanol concentration of 20%, obtained pulp has acceptable values of Kappa index and viscosity, and their corresponding paper sheets have a brightness of 27.4% ISO, a tensile index of 28.87 Nm/g, a burst index of 1.22 kPam2 /g and a tear index of 1.23 kNm<sup>2</sup> /g.

In the case of sunflower stems [54], the solid fraction of a treatment carried out at 180°C is cooked with ethanol (70%, 170°C for 2 h and a hydromodule of 8) giving rise to a pulp with properties (36.3% of pulp yield, 69.1% cellulose, 12.6% hemicellulose, 18.2% lignin, 551 mL/g viscosity, 3.8 km breaking length, 1.23% elongation, 1.15 kN/g burst index and 2.04 mNm<sup>2</sup> /g tear index) similar to that obtained by the soda process.

The influence of operating conditions (temperature from 160 to 180°C, time from 30 to 90 min and concentration of diethanolamine from 60 to 80%) on the pulping process of the solid fraction obtained from a hydrothermal treatment of rice straw (carried out at 190°C) on the characteristics of the pulp (yield, Kappa index, viscosity and degree of refining) and of the paper sheets obtained from them (length of rupture, elongation, burst index, tear index and brightness) was also studied [71]. It is deduced that it is convenient to operate at 162.5°C, 60 min and 70% of diethanolamine, since paper sheets present characteristics that deviate little from the optimal ones (less than 8% in the worst case), saving chemical reagents, energy for heating and immobilized capital for the installation, when operating with values of time and the concentration of diethanolamine medium and medium-low temperature, with respect to the maximums considered; likewise the values found for the yield and Kappa index deviate less than 14% with respect to the optimal values.

Autohydrolysed tagasaste wood was also submitted to ethanol and soda pulping procedures [25]. The autohydrolysis prior to ethanol pulping increases yields (53–60%); reduces Kappa index (28.8–34.6), but also viscosity (755–857 mL/g); and decreases paper strength (2.97–5.22 kNm/kg). However, applying a refining process to tagasaste pulp is found to improve its strength-related properties more markedly than in soda pulp from the same material (tensile index of 44 kNm/kg). In the case of *H. funifera*, the samples pretreated with sulphuric acid-catalysed autohydrolysis was subsequently submitted to soda, soda-anthraquinone, ethanolamine, ethylene glycol, diethanolamine and diethyleneglycol [94]. In this case, the best pulp of *H. funifera* pulp is obtained by cooking with 10% NaOH and 1% anthraquinone at 155°C for 30 min, exhibiting good values of yield (48.3%), viscosity (737 mL/g), Kappa index (15.2), tensile index (83.6 Nm/g), stretch (3.8%), burst index (7.34 kN/g) and tear index (3.20 mNm<sup>2</sup> /g). Moreover, the soda-anthraquinone pulps of raw material have better properties than the pulps from solid fraction of hydrothermal treatments.

#### **8.3 Use of residual liquors components obtained during pulping**

The valorization of lignin-rich black liquors generated from pulping processes is another transition path from the traditional pulp and paper industry to future biorefineries. Generally, residual lignins from black liquors are used to obtain energy for processing plants, mainly by combustion. However, the aromatic structure of lignin makes it a potential source for the production of new bio-based high-value products and chemicals, increasing the sustainability and competitiveness of this pulp and paper industry [86]. Other different fractions of lignin and compounds such as various polysaccharides present in these black liquors, which may not have

*Cellulose*

different purposes [53, 85].

condensation reactions with lignin [90].

[71], tagasaste [25] and *H. funifera* [94].

of the hemicellulose, reacting among others the acetyl groups (present in the form of esters in the hemicellulosic heteropolymers), which are released in the form of acetic acid. Its contribution to the generation of protons is 1700 to 1,000,000 times greater than that of water, so the contribution of aqueous protons to the hydrothermal process can be neglected once acetic acid has been generated. At the same time, there is total or partial solubilization of hemicelluloses and their conversion with good yields of oligosaccharides and monosaccharides, which can be used for

Other minor reactions associated with this type of process are the formation of products such as furfural from pentoses and HMF from hexoses; the generation of carbon dioxide by decomposition of carboxyl groups present in uronic acids; the condensation of some unstable molecules that intervene as reaction intermediates; the decomposition under severe conditions of products such as furfural, sensitive to acid concentration; the decomposition of HMF to formic and levulinic acids; and

Different studies with traditional woody materials such as eucalypt have shown a pre-extraction of hemicellulose prior to pulping process by hydrothermal processes [91–93]. In the same way, these hydrothermal processes have also been applied to alternative raw materials such as paulownia [55], sunflower stems [54], rice straw

The influence of the temperature (160–200°C) of the autohydrolysis process applied to paulownia on the composition of the resulting solid and liquid fractions has been studied [55]. It is found that the maximum concentrations of glucose, xylose, arabinose, acetic acid, furfural, HMF and oligomers of the resulting liquid

A similar study carried out with sunflower stems concludes that at 190°C the highest values are obtained for the glucose, xylose and arabinose contents of the liquid fraction of the hydrothermal treatment, with a yield of 24.5%, while the yield

In the case of rice straw, the influence of temperature (150–190°C), time (0 to 20 min after reaching the working temperature) and liquid/solid ratio (6:10) on the hydrothermal treatment, on the lignin content, on the yield of the resulting solid fraction and on the composition of the corresponding liquid phase (glucose, xylose, arabinose and acetic acid) was studied [71]. It follows that in order to obtain high values of glucose (1.92 g/L), xylose (3.97 g/L), arabinose (0.99 g/L) and acetic acid (1.96 g/L) concentrations, it is necessary to operate at high temperature (190°C) and low-medium conditions for time (15 min) and hydromodule (9), which allows capital savings by not operating with the maximum time and using the maximum hydromodule value. The yield obtained for the solid fraction is 88.1%, and the lignin content is 24.43%.

Finally, tagasaste wood was submitted to hydrothermal treatment at 175–185°C

Hydrothermal treatments under relatively mild operating conditions (temperature and time) do not cause significant alterations in the cellulose. In this way, solid

[25]. Then, a liquor containing a substantially increased amount of oligomers (between 16.6 and 47.7% as percentages with respect to the content of the raw material in each polymer fraction) is obtained. In the case of *H. funifera*, a sulphuric acid-catalysed hydrothermal treatment (170°C, 0, 20 min after reaching operating temperature, 8 liquid/solid ratio, and 0.3% sulphuric acid), gives a liquid fraction containing 4.62% of glucose, 10.56% of xylose, 1.28% of arabinose, and a solid frac-

**8.2 Pulping of the solid fraction from hydrothermal treatment**

fractions susceptible to delignification or pulping are obtained [53].

fraction correspond to when operating at maximum temperature.

of the solid fraction, which can be pulping, is 72.5% [54].

**28**

tion with a solid yield of 57.0%.

specific applications or their transformation into high value-added products may not be profitable, can also be valorized by gasification process [89].

Pulp and paper industry is estimated that moves around 70 million tonnes of lignin annually [95], of which only just over 1 million tonnes are currently marketed, corresponding to lignosulfonates, and which have an established market for use in various uses such as plasticizers and dispersion agents, whereas Kraft lignins are used in the recovery tanks of products from the paper plants themselves and only market around 100.000 tonnes per year. Finally, only a few hundred tonnes of lignins from the soda process come onto the market each year, although this quantity is expected to rise rapidly to around 10,000 tonnes due to the fact that an increasing number of small paper mills, which use agricultural waste and non-wood species to produce cellulose, are introducing lignin recovery processes as the only way to meet environmental effluent treatment specifications.

#### *8.3.1 Lignin applications*

Depending on the biomass feedstock, pulping technology and conditions and isolation procedures, lignin has distinct features that may render them useful for different applications. Purity, molar mass and chemical functionalities are some of the characteristics to take into account [96]. So, a detailed knowledge of lignin structure, composition and purity is required in order to determine its behaviour in different potential applications. In this sense, characterization of residual lignins from Kraft and soda-anthraquinone pulping of agriculture residues such as olive tree pruning [97] and wheat or barley straw [98], as well as vegetables like *L. leucocephala*, *C. proliferus*, and *H. funifera* [99, 100], has been carried out.

Among the different characteristics of lignin, its high heterogeneity is one of the most important, which not only affects its structure but also its high distribution of molecular weights (range from 1.000 to 300.000 Da for the same sample) [101]. Therefore, fractionation is one of the ways of obtaining reactive lignins. The preparation of lignin with a defined molecular weight distribution can be carried out by means of different processes: ultrafiltration, selective extraction with solvents and differential precipitation.

The technique of ultrafiltration and nanofiltration is one of the methods being investigated today, with the dual intention of on the one hand reducing the organic load contained in the digestion solution, for its subsequent reincorporation into the pulping process without the loss of inorganic reagents, and on the other obtaining valuable organic resources for use in the development of high-value-added materials. By means of ceramic membranes capable of filtering the residual liquor until the separation of substances smaller than 1 kDa, low molar lignin fractions (1000 g/ mol maximum) are obtained. After suitable purification processes, these lignins have a high phenolic hydroxyl content (and/or acid groups), high reactivity and low processing and handling temperatures. In this way, Toledano et al. [102] propose ultrafiltration as a fractionation process to separate different molecular weight lignin fractions from olive tree pruning organosolv black liquor.

Solvent extraction of lignin can be carried out primarily in two ways. In one case, lignin is extracted by a single solvent or a sequential use of multiple solvents. In the other case, a solvent is used to dissolve lignin and then precipitated using chemical (mainly with acids) treatments. Then, Domínguez-Robles et al. [103] used different proportions of acetone (40 and 60%) in water for lignin fractionation of two different sources (organosolv and soda wheat straw lignins), obtaining different fractions with different molar masses and functional groups. Finally, fractionation of the lignins by differential precipitation consists of extracting

**31**

gen and nitrogen.

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic…*

different lignin samples as the pH of the solution is gradually lowered. It is the most commonly used method because the simple addition of a strong acid is sufficient, compared to the high costs of the other two methods. However, it has a disadvantage derived from the formation of colloids during precipitation, which can greatly complicate the filtration process. In this sense, Domínguez-Robles et al. [104] have proposed an acid precipitation of wheat straw lignin from soda black liquor using three different inorganic acids (phosphoric, sulphuric and chloride acids) at three

Different lignin applications have been suggested depending on its properties. Then, poorly degraded lignin is employed as dispersants, surfactants and thermoplastic blends or copolymers [105–107] or as an aromatic compound platform to obtain fine chemicals such as polyols, benzene, xylene, toluene, vanillin, ferulic acid, etc. [87]. In contrast, extensively depolymerized lignin, therefore, with a high phenolic content, is suitable for coating, adhesives and composites [108–111]. In this sense, some examples of lignin valorization from alternative raw materials have been reported. Then, Borrero-López et al. [112] showed the possibility to produce olegels from soda lignin obtained from solid state fermented wheat straw; Tejado et al. [113] assayed soda-anthraquinone flax lignin and ethanol-water wild tamarind lignin to phenol-formaldehyde (PF) resin production; Domínguez-Robles et al. [103] investigated the use of soda wheat straw lignin as natural adhesive for the production of high-density fibre board; and Domínguez-Robles et al. [98] analysed Kraft, soda and organosolv wheat straw lignins as a binder material for electrodes in

Any proportion of the agricultural raw material non-suitable for pulp and paper

As commented above, different fractions of lignin and other compounds such as various polysaccharides can be obtained in lignin separation processes. Some of these fractions may not have specific applications, or their transformation into high-value-added products may not be profitable, so they may be suitable for a gasification process [89]. This consists of the partial oxidation of the lignocellulosic residues to obtain carbon monoxide, hydrogen, methane, nitrogen and carbonic anhydride mainly, in proportions that depend on the raw material considered and the conditions of the process. Three types of processes can be distinguished: (i) exothermic, using oxygen or air to obtain carbon monoxide or a mixture of carbon monoxide and nitrogen (lean gas); (ii) endothermic, which use water vapor to obtain carbon monoxide and hydrogen (synthesis gas); and (iii) balanced or mixed, using oxygen and water vapor or air and water vapor to obtain carbon monoxide and hydrogen or a mixture of carbon monoxide, hydro-

production, in addition to lignin and other compounds such as various polysaccharides obtained in lignin separation processes, may be converted—via pyrolysis—

Gasification gases can be used as fuels or to obtain chemicals. Among the latter, those obtained from carbon monoxide (methyl formate, formamide, formic acid, carbonyls, acrylic acid, etc.) and those obtained from carbon monoxide and hydrogen (ammonia, nitric acid, hydrazine, urea, hydrocyanic acid, aldehydes, explosives, etc.) can be distinguished. For example, pyrolysis of soda *H. funifera* lignin gives a gas mixture containing 1.13% H2, 31.79% CO and 1.86% CH4 by weight, whereas gasification of the same sample provides a mixture containing 0.18% H2,

into several types of fuels and petrochemical substitutes [1, 88].

different concentration levels, achieving pH values from 11 to 2.

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

rechargeable lithium batteries.

*8.3.2 Gasification of residual liquors components*

24.50% CO and 17.75% CH4, also by weight [39].

#### *Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

different lignin samples as the pH of the solution is gradually lowered. It is the most commonly used method because the simple addition of a strong acid is sufficient, compared to the high costs of the other two methods. However, it has a disadvantage derived from the formation of colloids during precipitation, which can greatly complicate the filtration process. In this sense, Domínguez-Robles et al. [104] have proposed an acid precipitation of wheat straw lignin from soda black liquor using three different inorganic acids (phosphoric, sulphuric and chloride acids) at three different concentration levels, achieving pH values from 11 to 2.

Different lignin applications have been suggested depending on its properties. Then, poorly degraded lignin is employed as dispersants, surfactants and thermoplastic blends or copolymers [105–107] or as an aromatic compound platform to obtain fine chemicals such as polyols, benzene, xylene, toluene, vanillin, ferulic acid, etc. [87]. In contrast, extensively depolymerized lignin, therefore, with a high phenolic content, is suitable for coating, adhesives and composites [108–111]. In this sense, some examples of lignin valorization from alternative raw materials have been reported. Then, Borrero-López et al. [112] showed the possibility to produce olegels from soda lignin obtained from solid state fermented wheat straw; Tejado et al. [113] assayed soda-anthraquinone flax lignin and ethanol-water wild tamarind lignin to phenol-formaldehyde (PF) resin production; Domínguez-Robles et al. [103] investigated the use of soda wheat straw lignin as natural adhesive for the production of high-density fibre board; and Domínguez-Robles et al. [98] analysed Kraft, soda and organosolv wheat straw lignins as a binder material for electrodes in rechargeable lithium batteries.

#### *8.3.2 Gasification of residual liquors components*

Any proportion of the agricultural raw material non-suitable for pulp and paper production, in addition to lignin and other compounds such as various polysaccharides obtained in lignin separation processes, may be converted—via pyrolysis into several types of fuels and petrochemical substitutes [1, 88].

As commented above, different fractions of lignin and other compounds such as various polysaccharides can be obtained in lignin separation processes. Some of these fractions may not have specific applications, or their transformation into high-value-added products may not be profitable, so they may be suitable for a gasification process [89]. This consists of the partial oxidation of the lignocellulosic residues to obtain carbon monoxide, hydrogen, methane, nitrogen and carbonic anhydride mainly, in proportions that depend on the raw material considered and the conditions of the process. Three types of processes can be distinguished: (i) exothermic, using oxygen or air to obtain carbon monoxide or a mixture of carbon monoxide and nitrogen (lean gas); (ii) endothermic, which use water vapor to obtain carbon monoxide and hydrogen (synthesis gas); and (iii) balanced or mixed, using oxygen and water vapor or air and water vapor to obtain carbon monoxide and hydrogen or a mixture of carbon monoxide, hydrogen and nitrogen.

Gasification gases can be used as fuels or to obtain chemicals. Among the latter, those obtained from carbon monoxide (methyl formate, formamide, formic acid, carbonyls, acrylic acid, etc.) and those obtained from carbon monoxide and hydrogen (ammonia, nitric acid, hydrazine, urea, hydrocyanic acid, aldehydes, explosives, etc.) can be distinguished. For example, pyrolysis of soda *H. funifera* lignin gives a gas mixture containing 1.13% H2, 31.79% CO and 1.86% CH4 by weight, whereas gasification of the same sample provides a mixture containing 0.18% H2, 24.50% CO and 17.75% CH4, also by weight [39].

*Cellulose*

specific applications or their transformation into high value-added products may

Pulp and paper industry is estimated that moves around 70 million tonnes of lignin annually [95], of which only just over 1 million tonnes are currently marketed, corresponding to lignosulfonates, and which have an established market for use in various uses such as plasticizers and dispersion agents, whereas Kraft lignins are used in the recovery tanks of products from the paper plants themselves and only market around 100.000 tonnes per year. Finally, only a few hundred tonnes of lignins from the soda process come onto the market each year, although this quantity is expected to rise rapidly to around 10,000 tonnes due to the fact that an increasing number of small paper mills, which use agricultural waste and non-wood species to produce cellulose, are introducing lignin recovery processes as the only way to meet

Depending on the biomass feedstock, pulping technology and conditions and isolation procedures, lignin has distinct features that may render them useful for different applications. Purity, molar mass and chemical functionalities are some of the characteristics to take into account [96]. So, a detailed knowledge of lignin structure, composition and purity is required in order to determine its behaviour in different potential applications. In this sense, characterization of residual lignins from Kraft and soda-anthraquinone pulping of agriculture residues such as olive tree pruning [97] and wheat or barley straw [98], as well as vegetables like *L. leucocephala*, *C. proliferus*, and *H. funifera* [99, 100], has been carried out.

Among the different characteristics of lignin, its high heterogeneity is one of the most important, which not only affects its structure but also its high distribution of molecular weights (range from 1.000 to 300.000 Da for the same sample) [101]. Therefore, fractionation is one of the ways of obtaining reactive lignins. The preparation of lignin with a defined molecular weight distribution can be carried out by means of different processes: ultrafiltration, selective extraction with solvents and

The technique of ultrafiltration and nanofiltration is one of the methods being investigated today, with the dual intention of on the one hand reducing the organic load contained in the digestion solution, for its subsequent reincorporation into the pulping process without the loss of inorganic reagents, and on the other obtaining valuable organic resources for use in the development of high-value-added materials. By means of ceramic membranes capable of filtering the residual liquor until the separation of substances smaller than 1 kDa, low molar lignin fractions (1000 g/ mol maximum) are obtained. After suitable purification processes, these lignins have a high phenolic hydroxyl content (and/or acid groups), high reactivity and low processing and handling temperatures. In this way, Toledano et al. [102] propose ultrafiltration as a fractionation process to separate different molecular weight

Solvent extraction of lignin can be carried out primarily in two ways. In one case, lignin is extracted by a single solvent or a sequential use of multiple solvents. In the other case, a solvent is used to dissolve lignin and then precipitated using chemical (mainly with acids) treatments. Then, Domínguez-Robles et al. [103] used different proportions of acetone (40 and 60%) in water for lignin fractionation of two different sources (organosolv and soda wheat straw lignins), obtaining different fractions with different molar masses and functional groups. Finally, fractionation of the lignins by differential precipitation consists of extracting

lignin fractions from olive tree pruning organosolv black liquor.

not be profitable, can also be valorized by gasification process [89].

environmental effluent treatment specifications.

*8.3.1 Lignin applications*

differential precipitation.

**30**

### **9. Conclusions**

The availability and concentration of wood in areas of easy access, the elevated fibre content, the cost of transport, the ease of storage as well as the stability of the raw material and its performance during the pulping process have supported the use of the wood in the pulp and paper industry. However, due to the numerous advantages of certain alternative raw materials (low-cost fibers, fast growth, low lignin content and fiber morphology, among others), they have proved to be a viable option as a starting raw material for the production of a wide range of different papers. On the other hand, taking into account the concept of lignocellulosic biorefinery, the pulp and paper industry is a good starting point since from its beginnings it not only produced pulp for paper but also energy. However, this industry needs different innovations to adapt even more to this concept. These innovations include the valorization of the extractives and hemicellulosic fractions through extraction prior to the pulping process, the valorization of black liquors through gasification or purification, the valorization of lignocellulosic waste through gasification or other processes such as saccharification and fermentation and also the introduction of new alternative raw materials to wood, as summarized in this work.

#### **Acknowledgements**

The authors are grateful to Spain's DGICyT, MICINN, for funding this research by Projects CTQ2016-78729-R and RTI2018-096080-B-C22 and the National Program FPU (Grant Number 454 FPU14/02278). The authors would also like to thank the Community of Madrid (Spain) for funding research through the project P2018/EMT-4348 (SUSTEC-CM).

#### **Conflict of interest**

The authors declare no conflict of interest.

#### **Author details**

María Eugenia Eugenio1 \*, David Ibarra1 , Raquel Martín-Sampedro1 , Eduardo Espinosa2 , Isabel Bascón2 and Alejandro Rodríguez2

1 Forestry Products Department, INIA-CIFOR, Madrid, Spain

2 Chemical Engineering Department, University of Córdoba, Córdoba, Spain

\*Address all correspondence to: mariaeugenia@inia.es

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**33**

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic…*

pulps during soda-AQ pulping and TCF/ECF bleaching. Industrial and Engineering Chemistry Research.

[10] Li H, Sun H, He Z. *Achnatherum inebrians* straw as a potential raw material for pulp and paper production.

[11] Shao S, Wu C, Chen K. Refining, dewatering, and paper properties of soda-anthraquinone (soda/AQ ) pulp from rice straw. BioResources.

[12] Sharma N, Godiyal RD, Bhawana Thapliyal BP, Anupam K. Pulping and bleaching of hydro distillation waste of citronella grass (*Cymbopogon winterianus Jowitt*) for papermaking. Waste and Biomass Valorization.

[13] Kaur D, Bhardwaj NK, Lohchab RK. A study on pulping of rice straw and impact of incorporation of chlorine dioxide during bleaching on pulp properties and effluents characteristics.

Journal of Cleaner Production.

[14] Tofanica BM, Puitel AC.

[15] Moore G. Non wood fiber applications in papermaking. In: Pira International; Leatherhead; Surrey UK;

[16] Sigoillot C, Camarero S, Vidal T, Record E, Asther M, Boada MP, et al. Comparison of different fungal enzymes from bleaching high-quality paper pulps. Journal of Biotechnology.

Optimization and design of alkaline pulping of rapeseed (*Brassica napus*) stalks. Chemical Engineering Communications.

Journal of Cleaner Production.

2013;**52**(13):4695-4703

2015;**101**:193-196

2017;**12**(3):4867-4880

2018;**9**(3):409-419

2018;**170**:174-182

2019;**206**(3):378-386

2005;**115**:333-343

1996

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

[1] Fahmy Y, Fahmy TYA, Mobarak F, El-Sakhawy M, Fadl MH. Agricultural residues (wastes) for manufacture of paper, board, and miscellaneous products: Background overview and future prospects. International Journal of ChemTech Research.

[2] Fahmy Y, Ibrahim H. Rice straw for paper making. Cellulose Chemistry and

[3] Fengel D, Wood WG. Chemistry, Ultrastructure, Reactions. Berlin: De

[4] Ralph J, Lundquist K, Brunow G, Lu F, Kim H, Schatz PF, et al. Lignins: Natural polymers from oxidative coupling of 4-hydroxyphenyl-

propanoids. Phytochemistry Reviews.

[5] CEPI (Confederation of European Paper Industries), Key Stadistics European Pulp and paper Industry. 2017

[6] Brännvall E. Overview of pulp and paper processes. In: The Ljungberg Texbook. Fiber and Polymer Technology, KTH, Stockholm; 2008

[7] Marques G, del Río JC, Gutiérrez A. Lipophilic extractives from several nonwoody lignocellulosic crops (flax, hemp, sisal, abaca) and their fate during alkaline pulping and TCF/ECF bleaching. Bioresource Technology.

[8] Hosseinpour R, Fatehi P, Latibari AJ, Ni Y, Sepiddehdam SJ. Canola straw chemimechanical pulping for pulp and paper production. Bioresource Technology. 2010;**101**(11):4193-4197

[9] Rencoret J, Marques G, Gutiérrez A, Jiménez-Barbero J, Martínez AT, del Río JC. Structural modifications of residual lignins from sisal and flax

2010;**101**(1):260-267

Technology. 1970;**4**(3):339-348

2017;**10**(2):424-448

**References**

Gruyter; 1984

2003;**3**:29-60

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

#### **References**

*Cellulose*

**9. Conclusions**

**Acknowledgements**

**Conflict of interest**

**Author details**

Eduardo Espinosa2

María Eugenia Eugenio1

P2018/EMT-4348 (SUSTEC-CM).

The authors declare no conflict of interest.

\*, David Ibarra1

1 Forestry Products Department, INIA-CIFOR, Madrid, Spain

2 Chemical Engineering Department, University of Córdoba, Córdoba, Spain

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

, Isabel Bascón2

\*Address all correspondence to: mariaeugenia@inia.es

provided the original work is properly cited.

The availability and concentration of wood in areas of easy access, the elevated fibre content, the cost of transport, the ease of storage as well as the stability of the raw material and its performance during the pulping process have supported the use of the wood in the pulp and paper industry. However, due to the numerous advantages of certain alternative raw materials (low-cost fibers, fast growth, low lignin content and fiber morphology, among others), they have proved to be a viable option as a starting raw material for the production of a wide range of different papers. On the other hand, taking into account the concept of lignocellulosic biorefinery, the pulp and paper industry is a good starting point since from its beginnings it not only produced pulp for paper but also energy. However, this industry needs different innovations to adapt even more to this concept. These innovations include the valorization of the extractives and hemicellulosic fractions through extraction prior to the pulping process, the valorization of black liquors through gasification or purification, the valorization of lignocellulosic waste through gasification or other processes such as saccharification and fermentation and also the introduction of new

The authors are grateful to Spain's DGICyT, MICINN, for funding this research

, Raquel Martín-Sampedro1

and Alejandro Rodríguez2

,

by Projects CTQ2016-78729-R and RTI2018-096080-B-C22 and the National Program FPU (Grant Number 454 FPU14/02278). The authors would also like to thank the Community of Madrid (Spain) for funding research through the project

alternative raw materials to wood, as summarized in this work.

**32**

[1] Fahmy Y, Fahmy TYA, Mobarak F, El-Sakhawy M, Fadl MH. Agricultural residues (wastes) for manufacture of paper, board, and miscellaneous products: Background overview and future prospects. International Journal of ChemTech Research. 2017;**10**(2):424-448

[2] Fahmy Y, Ibrahim H. Rice straw for paper making. Cellulose Chemistry and Technology. 1970;**4**(3):339-348

[3] Fengel D, Wood WG. Chemistry, Ultrastructure, Reactions. Berlin: De Gruyter; 1984

[4] Ralph J, Lundquist K, Brunow G, Lu F, Kim H, Schatz PF, et al. Lignins: Natural polymers from oxidative coupling of 4-hydroxyphenylpropanoids. Phytochemistry Reviews. 2003;**3**:29-60

[5] CEPI (Confederation of European Paper Industries), Key Stadistics European Pulp and paper Industry. 2017

[6] Brännvall E. Overview of pulp and paper processes. In: The Ljungberg Texbook. Fiber and Polymer Technology, KTH, Stockholm; 2008

[7] Marques G, del Río JC, Gutiérrez A. Lipophilic extractives from several nonwoody lignocellulosic crops (flax, hemp, sisal, abaca) and their fate during alkaline pulping and TCF/ECF bleaching. Bioresource Technology. 2010;**101**(1):260-267

[8] Hosseinpour R, Fatehi P, Latibari AJ, Ni Y, Sepiddehdam SJ. Canola straw chemimechanical pulping for pulp and paper production. Bioresource Technology. 2010;**101**(11):4193-4197

[9] Rencoret J, Marques G, Gutiérrez A, Jiménez-Barbero J, Martínez AT, del Río JC. Structural modifications of residual lignins from sisal and flax

pulps during soda-AQ pulping and TCF/ECF bleaching. Industrial and Engineering Chemistry Research. 2013;**52**(13):4695-4703

[10] Li H, Sun H, He Z. *Achnatherum inebrians* straw as a potential raw material for pulp and paper production. Journal of Cleaner Production. 2015;**101**:193-196

[11] Shao S, Wu C, Chen K. Refining, dewatering, and paper properties of soda-anthraquinone (soda/AQ ) pulp from rice straw. BioResources. 2017;**12**(3):4867-4880

[12] Sharma N, Godiyal RD, Bhawana Thapliyal BP, Anupam K. Pulping and bleaching of hydro distillation waste of citronella grass (*Cymbopogon winterianus Jowitt*) for papermaking. Waste and Biomass Valorization. 2018;**9**(3):409-419

[13] Kaur D, Bhardwaj NK, Lohchab RK. A study on pulping of rice straw and impact of incorporation of chlorine dioxide during bleaching on pulp properties and effluents characteristics. Journal of Cleaner Production. 2018;**170**:174-182

[14] Tofanica BM, Puitel AC. Optimization and design of alkaline pulping of rapeseed (*Brassica napus*) stalks. Chemical Engineering Communications. 2019;**206**(3):378-386

[15] Moore G. Non wood fiber applications in papermaking. In: Pira International; Leatherhead; Surrey UK; 1996

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[45] Deniz I, Kırcı H, Ates S.

of Tunisian Alfa stems (*Stipa tenacissima*)-effects of refining

[43] López F, Ariza J, Pérez I,

2011;**34**(3):1572-1582

2000;**72**:147-151

2009;**29**(1):16-26

2001;**37**(1):1-7

2005;**21**(2):211-221

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

[34] Jiménez L, Angulo V, Ramos E, De la Torre MJ, Ferrer JL. Comparison of various pulping process for production pulp from vine shoots. Industrial Crops

[35] López F, Ariza J, Pérez I, Jiménez L. Comparative study of paper sheets from olive tree wood pulp obtained by soda, sulfite or Kraft pulping. Bioresource

[36] Jiménez L, López F, Martínez C, Ferrer JL. Influence of the working conditions in the soda cooking of sorghum stalks on the features of the pulps, paper sheets and residual lyes obtained. A.T.I.P. 1992;**46**(6):174-176

[37] Jiménez L, Martínez C, López F. Influence of the soda cooking conditions on the features of the pulp and paper sheets obtained from sorghum stalks.

organosolv and soda pulping processes on the metals content of non-woody pulps. Bioresource Technology.

[39] Sánchez R, Rodríguez A, Requejo A, Ferrer A, Navarro E. Soda pulp and fuel gases synthesis from *Hesperaloe funifera*. Bioresource Technology.

[41] González Z, Rodríguez A, Vargas F, Jiménez L. Influence of the operational variables on the pulping and beating of the orange tree pruning. Industrial Crops and Products. 2013;**49**:785-789

A.T.I.P. 1997;**51**(6):231-236

[38] González M, Cantón L, Rodríguez A, Labidi J. Effect of

2008;**99**:6621-6625

2010;**101**:7032-7040

[40] Rodríguez A, Sánchez R, Eugenio ME, Yáñez R, Jiménez L. Soda-AQ pulping of residues from oil palm industry. Cellulose Chemistry and Technology. 2010;**44**(7-8):239-248

[42] Marrakchi Z, Khiari R, Oueslati H, Mauret E, Mhenni F.

and Products. 2006;**23**:122-130

Technology. 1999;**71**:83-86

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

[34] Jiménez L, Angulo V, Ramos E, De la Torre MJ, Ferrer JL. Comparison of various pulping process for production pulp from vine shoots. Industrial Crops and Products. 2006;**23**:122-130

*Cellulose*

2010;**4**:125-134

[17] Jiménez L, Rodríguez A. Valorization of agriculture residues by fractionation of their components. The Open Agricultural Journal.

[18] Jiménez L, Ferrer JL, García JC, Rodríguez A, Pérez I. Influence of ethanol pulping of wheat straw on the resulting paper sheets. Process Biochemistry. 2002;**37**(6):665-672

valorization of tagasaste (*Chamaecytisus proliferus*) under hydrothermal and pulp processing. Bioresource Technology.

[26] Jiménez L, Angulo V, Serrano L, Moral A, Rodríguez A. Almacenamiento de materias primas en la fabricación de pastas celulósicas. Ingeniería Química.

[27] TAPPI Standards. TAPPI Test

[28] National Renewable Energy

Laboratory (NREL). Chemical Analysis and Testing Laboratory Analytical Procedures. 2010. Retrieved from: http://www.eere.energy.gov/biomass/

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2010;**101**:7635-7640

2008;**458**:154-159

Methods. Atlanta; 1997

analyticalprocedures.html

2008;**99**:2881-2886

2001;**54**(2):217-220

2003;**60**(507):487-494

2005;**3**:387-394

Nacimiento JA, García MM,

Labidi J, Jiménez L. Rice straw pulp obtained by using various methods. Bioresource Technology.

[30] Ashori A. Nonwood fibers. A potential source of raw material in papermaking. Polymer-Plastics Technology and Engineering. 2006;**45**(10):1133-1136

[31] Feng ZN, Alen RJ. Soda AQ-pulping

[32] López F, Nacimiento JA, Díaz MJ, Eugenio ME, Pérez I, Rodríguez A, et al. Influence of process variables in the soda-anthraquinone pulping of sunflower stalks on the properties of the resulting paper. Afinidad.

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Jiménez L. Soda pulping of sunflower stalks. Influence of process variables on the resulting pulp. Journal of Industrial and Engineering Chemistry.

of wheat straw. Appita Journal.

[19] Jiménez L, Pérez I, López F, Ariza J, Rodríguez A. Ethanol-acetone pulping of wheat straw. Influence of the cooking and the beating of the pulps on the properties of the resulting paper sheets. Bioresource Technology.

[20] Jiménez L, Serrano L, Rodríguez A, Sánchez R. Soda-anthraquinone pulping

[21] Chen Z, Zhang H, He Z, Zhang L, Yue X. Bamboo as an emerging resource for worldwide pulping and papermaking. BioResources. 2019;**14**:3-5

[22] Miao C, Hui LF, Liu Z, Tang X. Evaluation of hemp root bast as a new material for papermaking. BioResources.

[23] Jiménez L, Rodríguez A, Pérez A, Moral A, Serrano L. Alternative raw materials and pulping process using clean technologies. Industrial Crops and

[24] Alfaro A, Pérez A, García JC,

[25] Alfaro A, López F, Pérez A, García JC, Rodríguez A. Integral

Rodríguez A. Ethanol and soda pulping of Tagasaste wood: Neural fuzzy modeling. Cellulose Chemistry and Technology. 2009;**43**(7-8):295-306

of palm oil empty fruit bunches and beating of the resulting pulps. Bioresource Technology.

2002;**83**(2):139-143

2009;**100**:1262-1267

2014;**9**:132-142

Products. 2008;**28**:11-16

López F, Zamudio MAM,

**34**

[35] López F, Ariza J, Pérez I, Jiménez L. Comparative study of paper sheets from olive tree wood pulp obtained by soda, sulfite or Kraft pulping. Bioresource Technology. 1999;**71**:83-86

[36] Jiménez L, López F, Martínez C, Ferrer JL. Influence of the working conditions in the soda cooking of sorghum stalks on the features of the pulps, paper sheets and residual lyes obtained. A.T.I.P. 1992;**46**(6):174-176

[37] Jiménez L, Martínez C, López F. Influence of the soda cooking conditions on the features of the pulp and paper sheets obtained from sorghum stalks. A.T.I.P. 1997;**51**(6):231-236

[38] González M, Cantón L, Rodríguez A, Labidi J. Effect of organosolv and soda pulping processes on the metals content of non-woody pulps. Bioresource Technology. 2008;**99**:6621-6625

[39] Sánchez R, Rodríguez A, Requejo A, Ferrer A, Navarro E. Soda pulp and fuel gases synthesis from *Hesperaloe funifera*. Bioresource Technology. 2010;**101**:7032-7040

[40] Rodríguez A, Sánchez R, Eugenio ME, Yáñez R, Jiménez L. Soda-AQ pulping of residues from oil palm industry. Cellulose Chemistry and Technology. 2010;**44**(7-8):239-248

[41] González Z, Rodríguez A, Vargas F, Jiménez L. Influence of the operational variables on the pulping and beating of the orange tree pruning. Industrial Crops and Products. 2013;**49**:785-789

[42] Marrakchi Z, Khiari R, Oueslati H, Mauret E, Mhenni F. Pulping and papermaking properties of Tunisian Alfa stems (*Stipa tenacissima*)-effects of refining process. Industrial Crops and Products. 2011;**34**(3):1572-1582

[43] López F, Ariza J, Pérez I, Jiménez L. Influence of the operating conditions on the properties of paper sheets obtained by kraft pulping of olive tree wood. Bioresource Technology. 2000;**72**:147-151

[44] Gominho J, Pereira H. Influence of raw-material and process variables in the kraft pulping of *Cynara cardunculus L*. Industrial Crops and Products. 2006;**24**(2):160-165

[45] Deniz I, Kırcı H, Ates S. Optimisation of wheat straw Triticum drum kraft pulping. Industrial Crops and Products. 2004;**19**(3):237-243

[46] Dutt D, Upadhyay JS, Singh B, Tyagi CH. Studies on *Hibiscus cannabinus* and *Hibiscus sabdariffa* as an alternative pulp blend for softwood: An optimization of kraft delignification process. Industrial Crops and Products. 2009;**29**(1):16-26

[47] López F, Ariza J, Eugenio ME, Díaz MJ, Pérez I, Jiménez L. Pulping and bleaching of pulp from olive tree residues. Process Biochemistry. 2001;**37**(1):1-7

[48] Díaz MJ, Eugenio ME, López F, Alejos J. Paper from olive tree residues. Industrial Crops and Products. 2005;**21**(2):211-221

[49] Jiménez L, Pérez I, de la Torre MJ, García JC. Influence of process variables on the properties of pulp and paper sheets obtained by sulphite pulping of olive tree wood. Wood Science and Technology. 2000;**34**:135-149

[50] Rudi H, Resalati H, Eshkiki RB, Kermanian H. Sunflower stalk neutral sulfite semi-chemical pulp: An alternative fiber source for production of fluting paper. Journal of Cleaner Production. 2016;**127**:562-566

[51] Khristova P, Kordsachi O, Patt R, Karar I, Khidera R. Environmentally friendly pulping and bleaching of bagasse. Industrial Crops and Products. 2006;**23**:131-139

[52] Hedjazi S, Kordsachia O, Patt R, Latibari AJ, Tschirner U. Alkaline sulfite–anthraquinone (AS/AQ ) pulping of wheat straw and totally chlorine free (TCF) bleaching of pulps. Industrial Crops and Products. 2009;**29**(1):27-36

[53] Rodríguez A, Rosal A, Jiménez L. Biorefinery of agriculture residues by fractionation of their components through hydrothermal and organosolv processes. Afinidad LXVII. 2010;**67**(545):14-21

[54] Caparrós S, Ariza J, López F, Nacimiento JA, Garrote G, Jiménez L. Hydrothermal treatment and ethanol pulping of sunflower stalks. Bioresource Technology. 2008;**99**:1368-1372

[55] Caparrós S, Díaz MJ, Ariza J, López F, Jiménez L. New perspectives for *Paulownia fortunei L.* valorisation of the authohydrolysis and pulping processes. Bioresource Technology. 2008;**99**:741-749

[56] Deykun I, Halysh V, Barbash V. Rapeseed straw as an alternative for pulping and papermaking. Cellulose Chemistry and Technology. 2018;**52**(9-10):833-839

[57] Díaz MJ, Alfaro A, García MM, Eugenio ME, Ariza J, López F. Ethanol pulping from tagasaste (*Chamaecytisus proliferus L.F. ssp palmensis*). A new promising source for cellulosic pulp. Industrial and Engineering Chemistry Research. 2004;**43**(8):1875-1881

[58] Ferrer A, Vega A, Ligero P, Rodríguez A. Pulping of empty fruit brunches (EFB) from the palm oil industry by formic acid. BioResources. 2011;**6**(4):4282-4301

[59] Jiménez L, Maestre F, de la Torre MJ. Organosolv pulping of wheat straw by use of methanol-water mixtures. TAPPI Journal. 1997;**80**(12):148-154

[60] Jiménez L, de la Torre MJ, Bonilla JL, Ferrer JL. Organosolv pulping of wheat straw by use of acetone-water mixtures. Process Biochemistry. 1998;**33**(1):229-238

[61] Jiménez L, Maestre F, Pérez I. Use of butanol-water mixtures for making wheat straw pulp. Wood Science and Technology. 1999;**33**:97-109

[62] Jiménez L, Pérez I, García JC, Rodríguez A. Influence of process variables in the ethanol pulping of olive tree trimmings. Bioresource Technology. 2001;**78**:63-69

[63] Lam HC, Bigot YL, Delmasa M, Avignon G. Formic acid pulping of rice straw. Industrial Crops and Products. 2001;**14**(1):65-71

[64] Ligero P, Villaverde JJ, Vega A, Bao M. Pulping cardoon (*Cynara cardunculus*) with peroxyformic acid (MILOX) in one single stage. Bioresource Technology. 2008;**99**(13):5687-5693

[65] Rodríguez A, Espinosa E, Domínguez-Robles J, Sánchez R, Bascón I, Rosal A. Pulp and paper processing. In: Different Solvents for Organosolv Pulping. Intechopen; 2018. pp. 33-54

[66] Sahin HT, Young RA. Autocatalyzed acetic acid pulping of jute. Industrial Crops and Products. 2008;**28**(1):24-28

**37**

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic…*

obtained from olive tree residues. Cellulose Chemistry and Technology.

[75] Jiménez L, Ramos E, De la Torre MJ, Pérez I, Ferrer JL. Bleaching of soda pulp of fibres of *Musa textilis nee*

(abaca) with peracetic acid. Bioresource Technology. 2008;**99**(5):1474-1480

[76] López F, Eugenio ME, Díaz MJ, Pérez I, Jiménez L. Bleaching of olive tree residues pulp with peracetic acid and comparative study with hydrogen peroxide. Industrial and Engineering Chemistry Research.

2006;**40**(3-4):237-242

2002;**41**(15):3518-3525

2007;**64**(530):479-485

[77] Jiménez L, Ramos E, De La Torre MJ, Pérez I. Bleaching of abaca (*Musa Textilis Nee*) soda pulp with sodium perborate. Afinidad.

[78] Jiménez L, Ramos E, De La

[79] Jiménez L, Serrano L,

of soda-anthraquinone and

Torre MJ, Ferrer JLECF. TCF bleaching methods as applied to abaca pulp. Afinidad. 2005;**62**(515):14-21

Rodríguez A, Ferrer A. TCF bleaching

diethanolamine pulp from oil palm empty fruit bunches. Bioresource Technology. 2009;**100**:1478-1481

[80] Camarero S, Garcı́a O, Vidal T, Colom J, del Rı́o JC, Gutiérrez A, et al. Efficient bleaching of non-wood high-quality paper pulp using laccasemediator system. Enzyme and Microbial Technology. 2004;**35**(2-3):113-120

[81] Fillat A, Colom JF, Vidal T. A new approach to the biobleaching of flax pulp with laccase using natural mediators. Bioresource Technology.

[82] Fillat U, Martín-Sampedro R, González Z, Ferrer A, Ibarra D, Eugenio ME. Biobleaching of orange

2010;**10**(11):4104-4110

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

properties of the resulting paper sheets. Bioresource Technology. 2001;**79**:23-27

[68] Jiménez L, Pérez A, De la Torre MJ, Moral A, Serrano L. Characterization of vine shoots, cotton stalks, *Leucaena leucocephala*, and *Chamaecyutisus proliferus*, and of their ethyleneglycol pulps. Bioresource Technology.

[69] Jiménez L, Rodríguez A, Serrano L, Moral A. Organosolv ethanolamine pulping of olive wood. Influence of the process variables on the strength properties. Biochemical Engineering

[70] Jiménez L, Angulo V, Rodríguez A, Sánchez R, Ferrer A. Pulp and paper from vine shoots. Neural fuzzy modelling of ethylene glycol pulping. Bioresource Technology.

[71] Rodríguez A, Moral A, Sánchez R, Jiménez L. Use of diethanolamine to obtain cellulosic pulps from solid fraction of hydrothermal treatment of

[72] Rodríguez A, Jiménez L, Ferrer JL. Use of oxygen in the delignification and bleaching of pulps. Appita Journal.

[73] López F, Díaz MJ, Eugenio ME, Ariza J, Rodríguez A, Jiménez L. Optimization of hydrogen peroxide in totally chlorine free bleaching of cellulosic pulp from olive tree residues. Bioresource Technology.

[74] Díaz MJ, Eugenio ME, López F, Ariza J, Vidal T. Influence of the pulping and TCF bleaching operating conditions on the properties of pulp and paper

2007;**98**:3487-3490

Journal. 2008;**39**:230-235

2009;**100**:756-762

2007;**60**(1):17-22

2003;**87**(3):255-261

rice straw. 2009;**65**:20-26

[67] Jiménez L, García JC, Pérez I, Ferrer JL, Chica A. Influence of the operating conditions in the acetone pulping of wheat straw on the

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

[67] Jiménez L, García JC, Pérez I, Ferrer JL, Chica A. Influence of the operating conditions in the acetone pulping of wheat straw on the properties of the resulting paper sheets. Bioresource Technology. 2001;**79**:23-27

*Cellulose*

2006;**23**:131-139

sulfite semi-chemical pulp: An

alternative fiber source for production of fluting paper. Journal of Cleaner Production. 2016;**127**:562-566

[58] Ferrer A, Vega A, Ligero P, Rodríguez A. Pulping of empty fruit brunches (EFB) from the palm oil industry by formic acid. BioResources.

Journal. 1997;**80**(12):148-154

[60] Jiménez L, de la Torre MJ, Bonilla JL, Ferrer JL. Organosolv pulping of wheat straw by use of acetone-water mixtures. Process Biochemistry. 1998;**33**(1):229-238

Technology. 1999;**33**:97-109

2001;**78**:63-69

2001;**14**(1):65-71

2008;**99**(13):5687-5693

pp. 33-54

2008;**28**(1):24-28

[65] Rodríguez A, Espinosa E, Domínguez-Robles J, Sánchez R, Bascón I, Rosal A. Pulp and paper processing. In: Different Solvents for Organosolv Pulping. Intechopen; 2018.

[66] Sahin HT, Young RA. Autocatalyzed acetic acid pulping of jute. Industrial Crops and Products.

[62] Jiménez L, Pérez I, García JC, Rodríguez A. Influence of process variables in the ethanol pulping of olive tree trimmings. Bioresource Technology.

[63] Lam HC, Bigot YL, Delmasa M, Avignon G. Formic acid pulping of rice straw. Industrial Crops and Products.

[64] Ligero P, Villaverde JJ, Vega A, Bao M. Pulping cardoon (*Cynara cardunculus*) with peroxyformic acid (MILOX) in one single stage. Bioresource Technology.

[61] Jiménez L, Maestre F, Pérez I. Use of butanol-water mixtures for making wheat straw pulp. Wood Science and

[59] Jiménez L, Maestre F, de la Torre MJ. Organosolv pulping of wheat straw by use of methanol-water mixtures. TAPPI

2011;**6**(4):4282-4301

[51] Khristova P, Kordsachi O, Patt R, Karar I, Khidera R. Environmentally friendly pulping and bleaching of bagasse. Industrial Crops and Products.

[52] Hedjazi S, Kordsachia O, Patt R, Latibari AJ, Tschirner U. Alkaline sulfite–anthraquinone (AS/AQ ) pulping of wheat straw and totally chlorine free (TCF) bleaching of pulps. Industrial Crops and Products. 2009;**29**(1):27-36

[53] Rodríguez A, Rosal A, Jiménez L. Biorefinery of agriculture residues by fractionation of their components through hydrothermal and organosolv

processes. Afinidad LXVII.

[54] Caparrós S, Ariza J, López F, Nacimiento JA, Garrote G,

[55] Caparrós S, Díaz MJ, Ariza J, López F, Jiménez L. New perspectives for *Paulownia fortunei L.* valorisation of the authohydrolysis and pulping processes. Bioresource Technology.

[56] Deykun I, Halysh V, Barbash V. Rapeseed straw as an alternative for pulping and papermaking. Cellulose

[57] Díaz MJ, Alfaro A, García MM, Eugenio ME, Ariza J, López F. Ethanol pulping from tagasaste (*Chamaecytisus proliferus L.F. ssp palmensis*). A new promising source for cellulosic pulp. Industrial and Engineering Chemistry Research. 2004;**43**(8):1875-1881

Chemistry and Technology. 2018;**52**(9-10):833-839

Jiménez L. Hydrothermal treatment and ethanol pulping of sunflower stalks. Bioresource Technology.

2010;**67**(545):14-21

2008;**99**:1368-1372

2008;**99**:741-749

**36**

[68] Jiménez L, Pérez A, De la Torre MJ, Moral A, Serrano L. Characterization of vine shoots, cotton stalks, *Leucaena leucocephala*, and *Chamaecyutisus proliferus*, and of their ethyleneglycol pulps. Bioresource Technology. 2007;**98**:3487-3490

[69] Jiménez L, Rodríguez A, Serrano L, Moral A. Organosolv ethanolamine pulping of olive wood. Influence of the process variables on the strength properties. Biochemical Engineering Journal. 2008;**39**:230-235

[70] Jiménez L, Angulo V, Rodríguez A, Sánchez R, Ferrer A. Pulp and paper from vine shoots. Neural fuzzy modelling of ethylene glycol pulping. Bioresource Technology. 2009;**100**:756-762

[71] Rodríguez A, Moral A, Sánchez R, Jiménez L. Use of diethanolamine to obtain cellulosic pulps from solid fraction of hydrothermal treatment of rice straw. 2009;**65**:20-26

[72] Rodríguez A, Jiménez L, Ferrer JL. Use of oxygen in the delignification and bleaching of pulps. Appita Journal. 2007;**60**(1):17-22

[73] López F, Díaz MJ, Eugenio ME, Ariza J, Rodríguez A, Jiménez L. Optimization of hydrogen peroxide in totally chlorine free bleaching of cellulosic pulp from olive tree residues. Bioresource Technology. 2003;**87**(3):255-261

[74] Díaz MJ, Eugenio ME, López F, Ariza J, Vidal T. Influence of the pulping and TCF bleaching operating conditions on the properties of pulp and paper

obtained from olive tree residues. Cellulose Chemistry and Technology. 2006;**40**(3-4):237-242

[75] Jiménez L, Ramos E, De la Torre MJ, Pérez I, Ferrer JL. Bleaching of soda pulp of fibres of *Musa textilis nee* (abaca) with peracetic acid. Bioresource Technology. 2008;**99**(5):1474-1480

[76] López F, Eugenio ME, Díaz MJ, Pérez I, Jiménez L. Bleaching of olive tree residues pulp with peracetic acid and comparative study with hydrogen peroxide. Industrial and Engineering Chemistry Research. 2002;**41**(15):3518-3525

[77] Jiménez L, Ramos E, De La Torre MJ, Pérez I. Bleaching of abaca (*Musa Textilis Nee*) soda pulp with sodium perborate. Afinidad. 2007;**64**(530):479-485

[78] Jiménez L, Ramos E, De La Torre MJ, Ferrer JLECF. TCF bleaching methods as applied to abaca pulp. Afinidad. 2005;**62**(515):14-21

[79] Jiménez L, Serrano L, Rodríguez A, Ferrer A. TCF bleaching of soda-anthraquinone and diethanolamine pulp from oil palm empty fruit bunches. Bioresource Technology. 2009;**100**:1478-1481

[80] Camarero S, Garcı́a O, Vidal T, Colom J, del Rı́o JC, Gutiérrez A, et al. Efficient bleaching of non-wood high-quality paper pulp using laccasemediator system. Enzyme and Microbial Technology. 2004;**35**(2-3):113-120

[81] Fillat A, Colom JF, Vidal T. A new approach to the biobleaching of flax pulp with laccase using natural mediators. Bioresource Technology. 2010;**10**(11):4104-4110

[82] Fillat U, Martín-Sampedro R, González Z, Ferrer A, Ibarra D, Eugenio ME. Biobleaching of orange tree pruning cellulosic pulp with xylanase and laccase mediator systems. Cellulose Chemistry and Technology. 2017;**51**(1-2):55-56

[83] Martín-Sampedro R, Rodríguez A, Requejo A, Eugenio ME. Improvement of TCF bleaching of olive tree pruning residue pulp by addition of a laccase and/or xylanase pre-treatment. BioResources. 2012;**7**(2):1488-1503

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**39**

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[104] Domínguez-Robles J, Espinosa E, Savy D, Rosal A, Rodríguez A. Biorefinery process combining Specel® process and selective lignin precipitation using mineral acids. BioResources.

[105] Saito T, Brown RH, Hunt MA, Pickel DL, Pickel JM, Messman JM, et al. Turning renewable resources into value-added polymer: Development of lignin-based thermoplastic. Green Chemistry. 2012;**14**:3295-3303

[106] Yang D, Li H, Qin Y, Zhong R, Bai M, Qiu X. Structure and properties of sodium lignosulfonate with different molecular weight used as dye dispersant. Journal of Dispersion Science and Technology. 2015;**36**:532-539

[107] Rojas OJ, Bullón J, Ysambertt F, Forgiarini A, Salager JL, Argyropoulos DS. Lignins as emulsion stabilizers. Materials, chemicals, and energy from forest biomass. ACS Symposium Series. 2007;**954**:182-199

[108] Ma C, Mei X, Fan Y, Zhang Z. Oxidative depolymerization of Kraft lignin and its application in the synthesis of lignin-phenol-formaldehyde resin. BioResources. 2018;**13**:1223-1234

[109] El Mansouri NE, Yuan Q,

and Bioenergy. 2012;**47**:99-108

[111] Gandini A, Belgacen MN, Guo ZX, Montanari S. Lignins as macromonomers for polyester and polyurethanes. In: Hu TQ, editor. Chemical Modification, Properties and Usage of Lignin. New York: Kluver Academic/Plenum; 2002. pp. 57-80

Huang F. Synthesis and characterization of kraft-lignin based epoxy resins. BioResources. 2011;**6**:2492-2503

[110] Sivasankarapillai G, McDonald AG, Li H. Lignin valorization by forming toughened lignin-co-polymers: Development of hyperbranched prepolymers for cross-linking. Biomass

2016;**11**:7061-7077

*DOI: http://dx.doi.org/10.5772/intechopen.90041*

side-streams generated in an olive tree pruning-based biorefinery: Bioethanol production and alkaline pulping. International Journal of Biological Macromolecules. 2017;**105**:238-251

[98] Domínguez-Robles J, Sánchez R,

[99] Domínguez-Robles J, Sánchez R, Espinosa E, Savy D, Mazzei P, Piccolo A, et al. Isolation and characterization of Gramineae and Fabaceae soda lignins. International Journal of Molecular

[100] De Andrés MA, Sequeiros A, Sánchez R, Requejo A, Rodríguez A, Serrano L. Production of paper and lignin from *Hesperaloe funifera*. Environmental Engineering and

[101] Tolbert A, Akinosho H, Khunsupat R, Naskar AK,

Luque R, Pineda A, Labidi J.

2014;**8**:836-856

Management Journal. 2016;**15**:2479-2486

Ragauskas AJ. Characterization and analysis of the molecular weight of lignin for biorefining studies. Biofuels Bioproducts Biorefinering.

[102] Toledano A, Serrano L, Balu AM,

Fractionation of organosolv lignin from olive tree clippings and its valorization to simple phenolic compounds. ChemSusChem. 2013;**6**(3):529-536

[103] Domínguez-Robles J, Tarrés Q, Delgado-Aguilar M, Rodríguez A, Espinosa FX, Mutjé P. Approaching a new generation of fiberboards taking advantage of self lignin as green adhesive. International Journal of Biological Macromolecules.

Díaz-Carrasco P, Espinosa E, García-Domínguez MT, Rodríguez A. Isolation and characterization of lignins from wheat straw: Application as binder in lithium batteries. International Journal of Biological Macromolecules.

2017;**104**:909-918

Sciences. 2017;**18**:327

*Alternative Raw Materials for Pulp and Paper Production in the Concept of a Lignocellulosic… DOI: http://dx.doi.org/10.5772/intechopen.90041*

side-streams generated in an olive tree pruning-based biorefinery: Bioethanol production and alkaline pulping. International Journal of Biological Macromolecules. 2017;**105**:238-251

*Cellulose*

2017;**51**(1-2):55-56

tree pruning cellulosic pulp with xylanase and laccase mediator systems. Cellulose Chemistry and Technology.

[83] Martín-Sampedro R, Rodríguez A, Requejo A, Eugenio ME. Improvement of TCF bleaching of olive tree pruning residue pulp by addition of a laccase and/or xylanase pre-treatment. BioResources. 2012;**7**(2):1488-1503

[90] Moreno AD, Ibarra D, Alvira P, Tomás-Pejó E, Ballesteros M. A review

[91] Martín-Sampedro R, Eugenio ME, Villar JC. Biobleaching of *Eucalyptus globulus* kraft pulps: Comparison between pulps obtained from exploded and non-exploded chips. Bioresource Technology. 2011;**102**:4530-4535

[92] Martín-Sampedro R, Eugenio ME,

Integration of kraft pulping on a forest biorefinery by the addition of a steam explosion pretreatment. BioResources.

[93] Martín-Sampedro R, Eugenio ME,

Moreno JA, Revilla E, Villar JC. Integration of a kraft pulping mill into a forest biorefinery: Pre-extraction of hemicellulose by steam explosion versus steam treatment. Bioresource

Technology. 2014;**53**:236-244

[94] Sánchez R, Rodríguez A, Navarro E, Requejo A, Jiménez L. Integrated utilization of the main components of *Hesperaloe funifera*. Biochemical Engineering Journal.

[95] Berlin A, Balakshin M. Industrial lignins: Analysis, properties, and applications. In: Bioenergy Research: Advances and Applications. 2014.

[96] Yuan TQ, Xu F, Sun RC. Role of lignin in a biorefinery: Separation characterization and valorization. Journal of Chemical Technology and Biotechnology. 2012;**88**:346-352

[97] Santos JI, Fillat Ú, Martín-Sampedro R, Eugenio ME, Negro MJ, Ballesteros I, et al. Evaluation from

Revilla E, Martín JA, Villar JC.

of biological delignification and detoxification methods for lignocellulosic bioethanol production. Critical Reviews in Biotechnology.

2015;**35**(3):342-354

2011;**6**:513-528

2011;**56**:130-136

pp. 315-336

[84] Martín-Sampedro R, Rodríguez A, Ferrer A, García-Fuentevilla LL, Eugenio ME. Biobleaching of pulp from oil palm empty fruit bunches with laccase and xylanase. Bioresource

[85] Moreno AD, Olsson L. Pretreatment

Technology. 2012;**110**:371-378

of lignocellulosic feedstocks. In: Sani RK, Krishnaraj RN, editors. Extremophilic Enzymatic Processing of Lignocellulosic Feedstocks to Bioenergy. Springer International Publishing AG;

[86] Ragauskas AJ, Beckham GT,

Science. 2014;**344**:1246843

Chemicals Society Review.

2018:852-908

s10668-018-0200-5

Biddy MJ, Chandra R, Chen F, Davis MF, et al. Lignin valorization: Improving lignin processing in the biorefinery.

[87] Schutyser W, Renders T, Van den Bosch S, Koelewijn SF, Beckham GT, Sels BF. Chemicals from lignin: An interplay of lignocellulose fractionation, depolymerisation, and upgrading.

[88] Fahmy TYA, Fahmy Y, Mobarak F, El-Sakhawy M, Abou-Zeid RE. Biomass pyrolysis: Past, present, and future. Environment, Development and Sustainability. 2018. DOI: 10.1007/

[89] Kang S, Li X, Fan J, Chang J. Hydrothermal conversion of lignin: A review. Renewable and Sustainable Energy Reviews. 2013;**27**:546-558

2017. pp. 31-52

**38**

[98] Domínguez-Robles J, Sánchez R, Díaz-Carrasco P, Espinosa E, García-Domínguez MT, Rodríguez A. Isolation and characterization of lignins from wheat straw: Application as binder in lithium batteries. International Journal of Biological Macromolecules. 2017;**104**:909-918

[99] Domínguez-Robles J, Sánchez R, Espinosa E, Savy D, Mazzei P, Piccolo A, et al. Isolation and characterization of Gramineae and Fabaceae soda lignins. International Journal of Molecular Sciences. 2017;**18**:327

[100] De Andrés MA, Sequeiros A, Sánchez R, Requejo A, Rodríguez A, Serrano L. Production of paper and lignin from *Hesperaloe funifera*. Environmental Engineering and Management Journal. 2016;**15**:2479-2486

[101] Tolbert A, Akinosho H, Khunsupat R, Naskar AK, Ragauskas AJ. Characterization and analysis of the molecular weight of lignin for biorefining studies. Biofuels Bioproducts Biorefinering. 2014;**8**:836-856

[102] Toledano A, Serrano L, Balu AM, Luque R, Pineda A, Labidi J. Fractionation of organosolv lignin from olive tree clippings and its valorization to simple phenolic compounds. ChemSusChem. 2013;**6**(3):529-536

[103] Domínguez-Robles J, Tarrés Q, Delgado-Aguilar M, Rodríguez A, Espinosa FX, Mutjé P. Approaching a new generation of fiberboards taking advantage of self lignin as green adhesive. International Journal of Biological Macromolecules. 2018;**108**:927-935

[104] Domínguez-Robles J, Espinosa E, Savy D, Rosal A, Rodríguez A. Biorefinery process combining Specel® process and selective lignin precipitation using mineral acids. BioResources. 2016;**11**:7061-7077

[105] Saito T, Brown RH, Hunt MA, Pickel DL, Pickel JM, Messman JM, et al. Turning renewable resources into value-added polymer: Development of lignin-based thermoplastic. Green Chemistry. 2012;**14**:3295-3303

[106] Yang D, Li H, Qin Y, Zhong R, Bai M, Qiu X. Structure and properties of sodium lignosulfonate with different molecular weight used as dye dispersant. Journal of Dispersion Science and Technology. 2015;**36**:532-539

[107] Rojas OJ, Bullón J, Ysambertt F, Forgiarini A, Salager JL, Argyropoulos DS. Lignins as emulsion stabilizers. Materials, chemicals, and energy from forest biomass. ACS Symposium Series. 2007;**954**:182-199

[108] Ma C, Mei X, Fan Y, Zhang Z. Oxidative depolymerization of Kraft lignin and its application in the synthesis of lignin-phenol-formaldehyde resin. BioResources. 2018;**13**:1223-1234

[109] El Mansouri NE, Yuan Q, Huang F. Synthesis and characterization of kraft-lignin based epoxy resins. BioResources. 2011;**6**:2492-2503

[110] Sivasankarapillai G, McDonald AG, Li H. Lignin valorization by forming toughened lignin-co-polymers: Development of hyperbranched prepolymers for cross-linking. Biomass and Bioenergy. 2012;**47**:99-108

[111] Gandini A, Belgacen MN, Guo ZX, Montanari S. Lignins as macromonomers for polyester and polyurethanes. In: Hu TQ, editor. Chemical Modification, Properties and Usage of Lignin. New York: Kluver Academic/Plenum; 2002. pp. 57-80

[112] Borrero-López AM, Blánquez A, Valencia C, Hernández M, Arias ME, Eugenio ME, et al. Valorization of soda lignin from wheat straw solid-state fermentation: Production of oleogels. ACS Sustainable Chemical Engineering. 2018;**6**(4):5198-5205

[113] Tejado A, Peña C, Labidi J, Echeverria JM, Mondragon I. Physicochemical characterization of lignins from different sources for use in phenol-formaldehyde resin synthesis. Bioresource Technology. 2007;**98**(8):1655-1663

Section 2

Structure

41

Section 2 Structure

*Cellulose*

2018;**6**(4):5198-5205

2007;**98**(8):1655-1663

[113] Tejado A, Peña C, Labidi J, Echeverria JM, Mondragon I. Physico-

chemical characterization of lignins from different sources for use in phenol-formaldehyde resin synthesis. Bioresource Technology.

[112] Borrero-López AM, Blánquez A, Valencia C, Hernández M, Arias ME, Eugenio ME, et al. Valorization of soda lignin from wheat straw solid-state fermentation: Production of oleogels. ACS Sustainable Chemical Engineering.

**40**

Chapter 3

Abstract

Materials

solid state properties

1. Introduction

solid waste in Africa.

43

Influence of Size Classifications on

the Structural and Solid-State

Characterization of Cellulose

is noted to influence the characteristics of the cellulose materials.

importance in improving the insulation properties of materials [4].

Keywords: cellulose, size classification, crystallinity, structural characterization,

Wood is one of the hard fibrous structural tissue and abundant natural materials on earth. It is an organic material with a composition of cellulose, hemicellulose, and lignin which has been used for many years as a basic need in construction materials and other purposes [1–3]. The effect of particle sizes on the thermal and mechanical properties of wood had gained popularity in recent years due to its

The environmental degeneration caused by solid waste from different activities had been a challenge to the waste management throughout the world. Nigeria, with a population over 180 million as at 2018, has the largest producer of residue and

Oluyamo Sunday Samuel and Adekoya Mathew Adefusika

Influence of size classification on the properties of cellulose materials has been a subject of neglect over the years. Researchers had the opinion that there exist no significant difference between the characteristics of bulk particulate materials and sizes of their constituents. However, it has been affirmed that increase in crystallinity index, increases the strength properties of cellulose materials. Therefore, there is need to establish the influence of size classification as it affects the properties of cellulose materials. This study focused on the influence of size classifications on the structural and solid State characterization of cellulose obtained from wood dust. The structure of the cellulose composed principally of crystalline cellulose (I and II) and amorphous cellulose. The crystallinity and the inter-planar spacing revealed different structural properties for the two size classifications. The elemental composition consists of Carbon (C), Oxygen (O), Sodium (Na) and Chlorine (Cl) with Carbon having the highest percentage. The surface morphology of the isolated cellulose appears fiber -like for the size classifications examined. The isolated cellulose exhibits good mechanical and solid state properties with promising applications in device utilization. Within the limit of the research, size classification

#### Chapter 3

## Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose Materials

Oluyamo Sunday Samuel and Adekoya Mathew Adefusika

#### Abstract

Influence of size classification on the properties of cellulose materials has been a subject of neglect over the years. Researchers had the opinion that there exist no significant difference between the characteristics of bulk particulate materials and sizes of their constituents. However, it has been affirmed that increase in crystallinity index, increases the strength properties of cellulose materials. Therefore, there is need to establish the influence of size classification as it affects the properties of cellulose materials. This study focused on the influence of size classifications on the structural and solid State characterization of cellulose obtained from wood dust. The structure of the cellulose composed principally of crystalline cellulose (I and II) and amorphous cellulose. The crystallinity and the inter-planar spacing revealed different structural properties for the two size classifications. The elemental composition consists of Carbon (C), Oxygen (O), Sodium (Na) and Chlorine (Cl) with Carbon having the highest percentage. The surface morphology of the isolated cellulose appears fiber -like for the size classifications examined. The isolated cellulose exhibits good mechanical and solid state properties with promising applications in device utilization. Within the limit of the research, size classification is noted to influence the characteristics of the cellulose materials.

Keywords: cellulose, size classification, crystallinity, structural characterization, solid state properties

#### 1. Introduction

Wood is one of the hard fibrous structural tissue and abundant natural materials on earth. It is an organic material with a composition of cellulose, hemicellulose, and lignin which has been used for many years as a basic need in construction materials and other purposes [1–3]. The effect of particle sizes on the thermal and mechanical properties of wood had gained popularity in recent years due to its importance in improving the insulation properties of materials [4].

The environmental degeneration caused by solid waste from different activities had been a challenge to the waste management throughout the world. Nigeria, with a population over 180 million as at 2018, has the largest producer of residue and solid waste in Africa.

One important waste from wood is the wood dust. This by-product usually constitutes menace to man and his environment as the material is usually disposed of sometimes indiscriminately in different locations which most often constitute environmental pollution [3]. Studied had shown that if well harness, wood dust may attract economic values to the country rather than the usual pollution.

higher plant cell wall cellulose and in tunicates. Iα can be converted to Iβin alkaline solution by hydrothermal treatments at a temperature of 260°C. Native cellulose is organized in fibrils, which are represented by the association of cellulose molecules. The native cellulose of higher plants possesses a high degree of polymerization (DP) of up to 10.000 β- anhydroglucose residues [14]. This indicates that the molecular weight is above 1.5 million (g/mol). The increase in crystalline regions increases the rigidity and decreases the elasticity of the polymeric substance. The accessibility of cellulose molecules affects the ratio of the crystalline region and the amorphous

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose…

Modification of cellulose is identified by addition of crystalline allomorphs, II, III, and IV. Mercerization (Alkali treatment) and regeneration (solubilization and subsequent recrystallization) are the two main methods of preparing celluloses II. However, when the time and the amount of chemical introduced in the treatment of native cellulose are not restricted to a predetermined pattern, it results to

Treatments with liquid ammonia with celluloses I and II produces celluloses IIII and IIIII. In addition, heating of IIII and IIIIII produces celluloses IVI and IVII [19, 20]. Structure and morphology of cellulose give a clearer picture of understanding the behavior of cellulose during chemical modification. It also gives understanding on the morphological changing of materials after hydrolysis. There are three structural levels that describe the complex structure of cellulose. These are molecular level (molecular mass, potential intramolecular and chemical constitution), supramolecular levels (crystal structure and intermolecular hydrogen-bonding system) and morphological levels (organization of crystals into microfibrils, the existence of different cell wall layers in the fibers, and other cellulose morphologies). These

One of the parameters used to study the total cellulose present in cellulosic materials is the crystallinity Index [21–25]. In addition, the presence of crystallinity in cellulose contributes greatly to its physical, chemical and mechanical properties [22, 26, 27]. The crystallinity index of cellulosic material has an influence on the stiffness, rigidity and the strength of the material. The increase in the crystallinity index (CI) is associated with high potential mechanical property and increase reinforcing capability of a cellulose material. Several techniques have been used to measure the crystallinity index. These techniques include; XRD, solid-state 13C NMR, infrared (IR) spectroscopy and Raman spectroscopy. The crystallinity index has been used for years in interpreting cellulose changes after treatment (physicochemical and biological). It has been reported that crystallinity index varies significantly depending on the measurement method. Among these methods, XRD is the mostly employed. Three different methods are commonly employed in calculating the CI from the raw spectrographic data on the XRD [23, 28–32]. The first method was established by [33], proposed for cellulose I. In this method, consideration was based on the ratio of the peak height between the intensity of the crystalline and the total intensity after subtraction of background signal at 18° (2θ) degrees. The idea behind the Segal equation is that there are no crystalline peaks near 18° for cellulose I, therefore any observed intensity would be due to amorphism region. [33] found a maximum at 18° but other authors have found maxima at values even higher, such as 20–22° [34]. Thus, [30] showed that a perfectly crystalline cellulose would still only give a Segal CrI value of 92% when the crystal is approximately the size of a good cotton crystal (FWHM = 1.7°). Furthermore, for a 100% amorphism, a pattern would have to be completely flat; something that never happens. Because there is no fundamentally sound method that is well proven for crystallinity determination, Segal method results remain fairly simple to obtain and give helpful information. Segal with other methods (peak de-convolution method, and amorphous subtraction) all has fundamental flaws.

levels determine both chemical and mechanical properties of cellulose.

region in the cellulose structure [15–18].

DOI: http://dx.doi.org/10.5772/intechopen.82849

the production of cellulose (I and II).

45

Cellulose is a formation of the composite, a versatile and widely natural-based material in nature that consists of glucose molecules which has various uses to man and used by man for thousands of years as building material, or energy source. It is a polymer that contains crystallites and displayed para-crystalline morphology [5]. The linear molecules are linked laterally by hydrogen bonds to form linear bundles which give rise to the crystalline structure. It has become one of the material's serving mankind for centuries and major subject in the history of polymer science in developing nation's economic and determination of polymeric crystal structures. Today, it is an important material which is widely used in industries (paper, pharm, food, etc.) and it has also served as an economic output in many countries of the world.

It has a general formula (C6H10O5)n, found in plants as microfibril and isolated from wide range of species from higher plants such as wood to green algae [6, 7]. It is a polymer that composed of amorphous and crystalline regions which varies depending on the plant species. Cellulose can be isolated from plants and non-plant sources. Isolation can be from a variety of sources such as (cotton, hemp, jute, sugarcane bagasse, rice straw, durra stalk, groundnut shell, etc.). The composition of chemical and cell dimensions depend on plants, origin and isolation method.

Cellulose can exist in its derivative forms namely rayon, cellulose acetate, cellulose nitrate, and ethyl cellulose. It is the main component of about half to one-third of plant tissues and categorized into three namely, α-cellulose, β-cellulose and γ-cellulose [8]. Solubility and precipitation nature are the major category upon which cellulose is based. In plants, it composed of a linear homopolymer of 1,4 β-glucopyranose units associated with hydrogen bonding and as a semicrystalline structure that is found and circulated from highly developed trees to primitive organisms [9, 10]. The chemical repeating unit is the β-1,4-linked glucose and structural repeat is β-cellobiose [11]. The repeating unit in cellulose is the anhydrocellulobiose and half a degree of polymerization (DP) gives rise to the number of repeating per molecule. It is higher in native cellulose than other group of cellulose which is usually due to the purification procedures. Van der Waals forces and hydrogen bonds tightly bound the glucose to each other to form crystalline structures called Elementary fibril. This consists of around 40 glucan chains, 40 Å widths, 30 Å tick and 100 Å long [12].

There are two main regions found in cellulose fibers. These are crystalline and amorphous. Crystalline are regions with a high order of microfibrils while less order of microfibrils is called amorphous. Amorphous material are materials that lack definite shape or formless. These regions vary proportions among the plants species. For this reason, the properties of cellulose materials depend largely on the material. The versatility of cellulose makes it important in it usage. The method of isolation or treatment, sources of cellulose give rise to different polymorphs with only a few exceptions. This may be due to molecular orientation and hydrogen bonding [3]. The polymorphic forms can be grouped into four: I, II, III, and IV which can be determined by XRD pattern. The first model of the crystalline structure of native cellulose of a monoclinic unit cell was developed by Mayer and Mish [13]. All native cellulose crystalline consists of CI with only a few exceptions and exhibits the same crystalline structure. It composed of two distinct allomorphs Iα(triclinic) and Iβ(monoclinic) depending on the biological origins. Iαstructure is metastable and dominated polymorph for most algae and bacteria, whereas Iβis dominant for

#### Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose… DOI: http://dx.doi.org/10.5772/intechopen.82849

higher plant cell wall cellulose and in tunicates. Iα can be converted to Iβin alkaline solution by hydrothermal treatments at a temperature of 260°C. Native cellulose is organized in fibrils, which are represented by the association of cellulose molecules. The native cellulose of higher plants possesses a high degree of polymerization (DP) of up to 10.000 β- anhydroglucose residues [14]. This indicates that the molecular weight is above 1.5 million (g/mol). The increase in crystalline regions increases the rigidity and decreases the elasticity of the polymeric substance. The accessibility of cellulose molecules affects the ratio of the crystalline region and the amorphous region in the cellulose structure [15–18].

Modification of cellulose is identified by addition of crystalline allomorphs, II, III, and IV. Mercerization (Alkali treatment) and regeneration (solubilization and subsequent recrystallization) are the two main methods of preparing celluloses II.

However, when the time and the amount of chemical introduced in the treatment of native cellulose are not restricted to a predetermined pattern, it results to the production of cellulose (I and II).

Treatments with liquid ammonia with celluloses I and II produces celluloses IIII and IIIII. In addition, heating of IIII and IIIIII produces celluloses IVI and IVII [19, 20].

Structure and morphology of cellulose give a clearer picture of understanding the behavior of cellulose during chemical modification. It also gives understanding on the morphological changing of materials after hydrolysis. There are three structural levels that describe the complex structure of cellulose. These are molecular level (molecular mass, potential intramolecular and chemical constitution), supramolecular levels (crystal structure and intermolecular hydrogen-bonding system) and morphological levels (organization of crystals into microfibrils, the existence of different cell wall layers in the fibers, and other cellulose morphologies). These levels determine both chemical and mechanical properties of cellulose.

One of the parameters used to study the total cellulose present in cellulosic materials is the crystallinity Index [21–25]. In addition, the presence of crystallinity in cellulose contributes greatly to its physical, chemical and mechanical properties [22, 26, 27]. The crystallinity index of cellulosic material has an influence on the stiffness, rigidity and the strength of the material. The increase in the crystallinity index (CI) is associated with high potential mechanical property and increase reinforcing capability of a cellulose material. Several techniques have been used to measure the crystallinity index. These techniques include; XRD, solid-state 13C NMR, infrared (IR) spectroscopy and Raman spectroscopy. The crystallinity index has been used for years in interpreting cellulose changes after treatment (physicochemical and biological). It has been reported that crystallinity index varies significantly depending on the measurement method. Among these methods, XRD is the mostly employed. Three different methods are commonly employed in calculating the CI from the raw spectrographic data on the XRD [23, 28–32]. The first method was established by [33], proposed for cellulose I. In this method, consideration was based on the ratio of the peak height between the intensity of the crystalline and the total intensity after subtraction of background signal at 18° (2θ) degrees. The idea behind the Segal equation is that there are no crystalline peaks near 18° for cellulose I, therefore any observed intensity would be due to amorphism region. [33] found a maximum at 18° but other authors have found maxima at values even higher, such as 20–22° [34]. Thus, [30] showed that a perfectly crystalline cellulose would still only give a Segal CrI value of 92% when the crystal is approximately the size of a good cotton crystal (FWHM = 1.7°). Furthermore, for a 100% amorphism, a pattern would have to be completely flat; something that never happens. Because there is no fundamentally sound method that is well proven for crystallinity determination, Segal method results remain fairly simple to obtain and give helpful information. Segal with other methods (peak de-convolution method, and amorphous subtraction) all has fundamental flaws.

One important waste from wood is the wood dust. This by-product usually constitutes menace to man and his environment as the material is usually disposed of sometimes indiscriminately in different locations which most often constitute environmental pollution [3]. Studied had shown that if well harness, wood dust may

Cellulose is a formation of the composite, a versatile and widely natural-based material in nature that consists of glucose molecules which has various uses to man and used by man for thousands of years as building material, or energy source. It is a polymer that contains crystallites and displayed para-crystalline morphology [5]. The linear molecules are linked laterally by hydrogen bonds to form linear bundles which give rise to the crystalline structure. It has become one of the material's serving mankind for centuries and major subject in the history of polymer science in developing nation's economic and determination of polymeric crystal structures. Today, it is an important material which is widely used in industries (paper, pharm, food, etc.) and it has also served as an economic output in many countries of the

It has a general formula (C6H10O5)n, found in plants as microfibril and isolated from wide range of species from higher plants such as wood to green algae [6, 7]. It is a polymer that composed of amorphous and crystalline regions which varies depending on the plant species. Cellulose can be isolated from plants and non-plant sources. Isolation can be from a variety of sources such as (cotton, hemp, jute, sugarcane bagasse, rice straw, durra stalk, groundnut shell, etc.). The composition of chemical and cell dimensions depend on plants, origin and isolation method. Cellulose can exist in its derivative forms namely rayon, cellulose acetate, cellulose nitrate, and ethyl cellulose. It is the main component of about half to one-third of plant tissues and categorized into three namely, α-cellulose, β-cellulose and γ-cellulose [8]. Solubility and precipitation nature are the major category upon which cellulose is based. In plants, it composed of a linear homopolymer of 1,4 β-glucopyranose units associated with hydrogen bonding and as a semicrystalline structure that is found and circulated from highly developed trees to primitive organisms [9, 10]. The chemical repeating unit is the β-1,4-linked glucose and structural repeat is β-cellobiose [11]. The repeating unit in cellulose is the anhydrocellulobiose and half a degree of polymerization (DP) gives rise to the number of repeating per molecule. It is higher in native cellulose than other group of cellulose which is usually due to the purification procedures. Van der Waals forces and hydrogen bonds tightly bound the glucose to each other to form crystalline structures called Elementary fibril. This consists of around 40 glucan chains,

There are two main regions found in cellulose fibers. These are crystalline and amorphous. Crystalline are regions with a high order of microfibrils while less order of microfibrils is called amorphous. Amorphous material are materials that lack definite shape or formless. These regions vary proportions among the plants species. For this reason, the properties of cellulose materials depend largely on the material. The versatility of cellulose makes it important in it usage. The method of isolation or treatment, sources of cellulose give rise to different polymorphs with only a few exceptions. This may be due to molecular orientation and hydrogen bonding [3]. The polymorphic forms can be grouped into four: I, II, III, and IV which can be determined by XRD pattern. The first model of the crystalline structure of native cellulose of a monoclinic unit cell was developed by Mayer and Mish [13]. All native cellulose crystalline consists of CI with only a few exceptions and exhibits the same crystalline structure. It composed of two distinct allomorphs Iα(triclinic) and Iβ(monoclinic) depending on the biological origins. Iαstructure is metastable and dominated polymorph for most algae and bacteria, whereas Iβis dominant for

attract economic values to the country rather than the usual pollution.

world.

Cellulose

44

40 Å widths, 30 Å tick and 100 Å long [12].

Available researches into isolation of cellulose focused mostly on thermal and mechanical properties. Hitherto, there is no available information about the influence of size classifications on the structural and solid state characterization of cellulose materials. Although, some school of thought have the notion that size classification has no significant influence on the properties of cellulose materials.

3. Theoretical consideration

DOI: http://dx.doi.org/10.5772/intechopen.82849

3.1 X-ray diffraction method

analyses were performed.

using [37, 38].

given as

47

by examine the diffraction patterns.

One of the reliable techniques to determine the crystal structure of any material is the X-ray diffraction (XRD). The crystalline phase of the material can be obtained

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose…

The XRD patterns of the two size classifications were obtained using a Philips PW 3710 X'pert Pro diffractometer (Philips Analyical, Almelo, Netherlands) with a Cu-Kα monochromator of wavelength, λ = 1.540598 Åm, in the range of 10–50° (2θ) generated at 15 kV. All experiments were repeated twice and duplicate X-ray

The Interplanar spacing (d-spacing) was calculated from the Bragg equation

where n is the order of reflection, λ is the wavelength of the incident X-rays (m),

The crystallinity index (CrI, %) was obtained from the XRD diffraction pattern. The patterns where engaged to determine the crystallinity parameters of cellulose derived from different size classifications of the wood dust samples. The crystallin-

where I020 is the maximum intensity of the lattice diffraction and Iam is the low intensity peak at the amorphous region of the baseline at 2θ, approximately 18°. The average crystallite sizes (L) in the isolated cellulose samples were calculated

<sup>L</sup> <sup>¼</sup> <sup>K</sup> � <sup>λ</sup>

where K is a constant whose value is given as 0.91, θ is the Bragg's angle (°), and His the intensity of the full width at half maximum (FWHM)corresponding to a

The Surface chain W occupying a layer that is approximately 0.57 nm thick is

<sup>W</sup> <sup>¼</sup> ð Þ <sup>L</sup> � <sup>2</sup><sup>h</sup> <sup>2</sup>

The determination of the monoclinic and triclinic structure for the two size classifications was calculated from the method developed by [37]. The isolated cellulose was categorized into Iα or Iβ predominant form by employing discriminant analysis. The function which discriminates between them (the monoclinic and

where d1ð Þ nm is the d-spacing of the Iβ (11̅0) peak and d2ð Þ nm is the d-spacing of the Iβ (110) peak. Z > 0 indicates that cellulose is rich in the Iα form and Z < 0

d is the interplanar spacing of the crystal, and θ is the Bragg's angle (°).

CrI <sup>¼</sup> <sup>I</sup><sup>020</sup> � Iam I<sup>020</sup>

ity index was calculated according to [33], as followed Eq. (2),

from the XRD line broadening using the Scherrer's equation

high intensity peak of the diffraction plane.

triclinic structure) is given as:

indicates that Iβ is the predominant form.

nλ ¼ 2d sin θ (1)

� 100 (2)

<sup>H</sup> � Cos<sup>θ</sup> (3)

<sup>L</sup><sup>2</sup> (4)

Z ¼ 1693d<sup>1</sup> � 902d<sup>2</sup> � 549 (5)

This effect is however well established for wood bulk and particle materials [2, 35, 36]. It is important to note that cellulose particles are presented in differing sizes in material processes and applications.

Guarea thompsonii is a species of plant from the family of Meliaceae. It is a hard wood that is naturally durable, resistant to impregnation, medium shrinkage and has a desired compressive advantage for concrete as a structural material.

Therefore in the present research, cellulose particles isolated from Guarea thompsonii are classified into two categories while the structural and solid state characterizations are determined.

#### 2. Method

#### 2.1 Material

Wood specie (Guarea thompsonii) was selected from a sawmill in the area of research and authenticated at the Department of Forestry and Wood Technology, Federal University of Technology, Akure (FUTA), Nigeria. The sample was processed into wood dust and sieved into two size classifications (424–599 μm and 600–849 μm) at the Department of Materials and Metallurgical Engineering (FUTA). Analytical grades chemical used were Sodium chlorite (NaClO2) (Sigma-Aldrich, Steinheim, Germany), sodium hydroxide (NaOH) (British Drug House, Darmstadt, Germany), and acetic acid (Sigma-Aldrich, Steinheim, Germany).

#### 2.2 Pre-treatment of material

The obtained sample after processed to wood dust were sieved using a Wiley mechanical sieve shaker (Pascal Engineering, Sussex, England) and the wood dust with two size classifications (425–599 μm and 600–849 μm) were obtained.

#### 2.3 Pulping procedure

The two classifications of the wood dust were pulped in a water bath at 90°C under atmospheric pressure with the ratio of wood to liquor of 1:20, using 20% NaOH for 90 minutes. The pulped was obtained by filtration after digestion and washed thoroughly with water until it was free of residual alkali. The pulp yield was oven-dried at 105°C to a constant weight and stored for further processing.

#### 2.4 Bleaching procedure

1000 mL of hot distilled water, 12 g of NaClO2, and 3 mL of acetic acid were added to approximately 20 g of oven-dried pulp sample in a 2-L Erlenmeyer flask. The flask was covered and the mixture heated in a water bath at 70°C for 30 minutes with intermittent stirring. After the first 30 minutes in the water bath, another 12 g of NaClO2 and 3 mL of acetic acid was added with intermittent stirring and sustained for another 30 minutes before switching the bath off. The sample was allowed to settle down for 24 hours in the water bath. After digestion, the bleach was obtained by filtration and washed thoroughly with water until it was free of residual alkali and chlorine. The obtained sample was dried at 105°C to a constant weight.

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose… DOI: http://dx.doi.org/10.5772/intechopen.82849

#### 3. Theoretical consideration

Available researches into isolation of cellulose focused mostly on thermal and mechanical properties. Hitherto, there is no available information about the influence of size classifications on the structural and solid state characterization of cellulose materials. Although, some school of thought have the notion that size classification has no significant influence on the properties of cellulose materials. This effect is however well established for wood bulk and particle materials [2, 35, 36]. It is important to note that cellulose particles are presented in differing

Guarea thompsonii is a species of plant from the family of Meliaceae. It is a hard wood that is naturally durable, resistant to impregnation, medium shrinkage and has a desired compressive advantage for concrete as a structural material. Therefore in the present research, cellulose particles isolated from Guarea thompsonii are classified into two categories while the structural and solid state

Wood specie (Guarea thompsonii) was selected from a sawmill in the area of research and authenticated at the Department of Forestry and Wood Technology, Federal University of Technology, Akure (FUTA), Nigeria. The sample was processed into wood dust and sieved into two size classifications (424–599 μm and 600–849 μm) at the Department of Materials and Metallurgical Engineering (FUTA). Analytical grades chemical used were Sodium chlorite (NaClO2) (Sigma-Aldrich, Steinheim, Germany), sodium hydroxide (NaOH) (British Drug House, Darmstadt, Germany), and acetic acid (Sigma-Aldrich, Steinheim, Germany).

The obtained sample after processed to wood dust were sieved using a Wiley mechanical sieve shaker (Pascal Engineering, Sussex, England) and the wood dust with two size classifications (425–599 μm and 600–849 μm) were obtained.

The two classifications of the wood dust were pulped in a water bath at 90°C under atmospheric pressure with the ratio of wood to liquor of 1:20, using 20% NaOH for 90 minutes. The pulped was obtained by filtration after digestion and washed thoroughly with water until it was free of residual alkali. The pulp yield was

1000 mL of hot distilled water, 12 g of NaClO2, and 3 mL of acetic acid were added to approximately 20 g of oven-dried pulp sample in a 2-L Erlenmeyer flask. The flask was covered and the mixture heated in a water bath at 70°C for 30 minutes with intermittent stirring. After the first 30 minutes in the water bath, another 12 g of NaClO2 and 3 mL of acetic acid was added with intermittent stirring and sustained for another 30 minutes before switching the bath off. The sample was allowed to settle down for 24 hours in the water bath. After digestion, the bleach was obtained by filtration and washed thoroughly with water until it was free of residual alkali and

oven-dried at 105°C to a constant weight and stored for further processing.

chlorine. The obtained sample was dried at 105°C to a constant weight.

sizes in material processes and applications.

characterizations are determined.

2.2 Pre-treatment of material

2.3 Pulping procedure

2.4 Bleaching procedure

46

2. Method

Cellulose

2.1 Material

#### 3.1 X-ray diffraction method

One of the reliable techniques to determine the crystal structure of any material is the X-ray diffraction (XRD). The crystalline phase of the material can be obtained by examine the diffraction patterns.

The XRD patterns of the two size classifications were obtained using a Philips PW 3710 X'pert Pro diffractometer (Philips Analyical, Almelo, Netherlands) with a Cu-Kα monochromator of wavelength, λ = 1.540598 Åm, in the range of 10–50° (2θ) generated at 15 kV. All experiments were repeated twice and duplicate X-ray analyses were performed.

The Interplanar spacing (d-spacing) was calculated from the Bragg equation using [37, 38].

$$n\lambda = 2d\sin\theta\tag{1}$$

where n is the order of reflection, λ is the wavelength of the incident X-rays (m), d is the interplanar spacing of the crystal, and θ is the Bragg's angle (°).

The crystallinity index (CrI, %) was obtained from the XRD diffraction pattern. The patterns where engaged to determine the crystallinity parameters of cellulose derived from different size classifications of the wood dust samples. The crystallinity index was calculated according to [33], as followed Eq. (2),

$$\text{CrI} = \frac{I\_{020} - I\_{am}}{I\_{020}} \times 100\tag{2}$$

where I020 is the maximum intensity of the lattice diffraction and Iam is the low intensity peak at the amorphous region of the baseline at 2θ, approximately 18°.

The average crystallite sizes (L) in the isolated cellulose samples were calculated from the XRD line broadening using the Scherrer's equation

$$L = \frac{K \times \lambda}{H \times \text{Cost}\theta} \tag{3}$$

where K is a constant whose value is given as 0.91, θ is the Bragg's angle (°), and His the intensity of the full width at half maximum (FWHM)corresponding to a high intensity peak of the diffraction plane.

The Surface chain W occupying a layer that is approximately 0.57 nm thick is given as

$$W = \frac{(L - 2h)^2}{L^2} \tag{4}$$

The determination of the monoclinic and triclinic structure for the two size classifications was calculated from the method developed by [37]. The isolated cellulose was categorized into Iα or Iβ predominant form by employing discriminant analysis. The function which discriminates between them (the monoclinic and triclinic structure) is given as:

$$Z = 1693d\_1 - 902d\_2 - 549\tag{5}$$

where d1ð Þ nm is the d-spacing of the Iβ (11̅0) peak and d2ð Þ nm is the d-spacing of the Iβ (110) peak. Z > 0 indicates that cellulose is rich in the Iα form and Z < 0 indicates that Iβ is the predominant form.

#### 3.2 FTIR spectroscopy measurement

Fourier transform infrared (FTIR) spectroscopy is a mature analytical technique employed to examine the microscopic area of a materials. FTIR spectra of powder samples of cellulose were obtained using a Thermo Nicolet 5700 FTIR spectrometer (Nicolet, Madison, WI, USA). The Spectra were acquired over the range 500– 4000 cm<sup>1</sup> at a resolution of 2 cm<sup>1</sup> for samples in pellet form prepared by mixing 1.0 mg of powder samples with 200.0 mg KBr spectroscopic grade. The spectra obtained were used for rapid information about the chemical structure of the cellulose samples.

#### 3.3 Scanning Electron MicroscopeMeasurement

The morphological characterization of composite materials can be investigated by the Scanning Electron Microscopy (SEM). It is a popular and powerful technique for imaging the surface of a material (surface topology, morphology and chemical composition) [39]. The image resolution depends on the property of the electron and the electron probe interaction with the specimen. SEM analysis was performed on the isolated cellulose obtained of the two size classifications using FEI NOVA 200 NanoSEM equipment (FEI Company, Hillsboro Oregon, USA) with an accelerating voltage of up to 30 kV and a resolution of up to 1 nm to observe the morphology of the cellulose obtained.

regeneration (solubilization and recrystallization) and mercerization (aqueous

the obvious peaks of doublet intensity at 2θ = 20.2–20.4°C.

4.1.1 Investigation of the crystallites structure of cellulose by XRD

possible imperfections of the crystal lattice are neglected by the method.

From this result, it can be concluded that alkali treatment in pretreatment process led to the change of cellulose allomorph from type I; the native cellulose found in nature, to type I and II; the regenerated cellulose which is the most stable crystalline form. Moreover, the acid hydrolysis which removed the amorphous region out from the cellulose led to re-crystallization was the main cause to obtain

XRD of isolated cellulose obtained for different size classifications for Guarea thompsonii (a) 425–599 μm

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose…

The average dimensions of the elementary crystallites perpendicular to the (110), ̅ (110) and (020) crystallographic planes of the mixture of cellulose I and cellulose II with amorphous can be calculated using the Scherrer's equation, by measuring the full widths at half maximum (FWHM) of the different diffraction peaks, assuming that the finite size of crystallites dominate the broadening of the X-ray reflections. These values have to be considered as a lower bound since instrumental broadening and

The results obtained from the XRD profiles of samples in Figure 1 are presented in Tables 1 and 2. In this, only the length perpendicular to the (020) plane could be calculated since the (11̅0) and (110) reflections in the XRD profile overlapped each other. An average crystallite length of about 1.742 nm and 1.748 nm were obtained Guarea thompsonii of 425 μm 599 μm and 600 μm 800 μm size classifications. The inter-planar spacing (d-spacing) values of the cellulose spectra for most prominent peak with crystal plane of preferred orientation along the (020) were 3.933 Å m and 3.982 Å m for Guarea thompsonii of 425–599 μm and 600–849 μm

Classification (μm) (11̅0) (110) (004) (020)

Band position (2θ) and d-spacing of crystalline cellulose of Guarea thompsonii.

425–599 14.754 5.999 17.044 5.198 34.908 2.568 22.591 3.933 600–849 14.721 6.013 16.726 5.293 34.992 2.562 22.308 3.982

2θ d (Å) 2θ d (Å) 2θ d (Å) 2θ d (Å)

sodium hydroxide treatments) [27].

DOI: http://dx.doi.org/10.5772/intechopen.82849

Figure 1.

(b) 600–849 μm.

Table 1.

49

#### 4. Results

#### 4.1 X-ray diffraction (XRD) of cellulose

X-ray diffraction (XRD) is a method generally used to determine the crystallinity of materials, interplanar distances etc. The free hydroxyl groups present in the cellulose macromolecules are likely to be involved in a number of intramolecular and intermolecular hydrogen bonds, which may give rise to various ordered crystalline arrangements [40, 41].

In order to evaluate and determine the intensities of the diffraction bands, establish the crystalline and amorphous areas and determine the crystallite sizes of the cellulose, the X-ray diffractogram (Figure 1) was adopted. The crystallographic planes from the diffractogram are labeled according to the cellulose structure.

The diffractograms showed that 12.414–14.755°C (2θ), 16.910–17.127°C (2θ), 18.01°C (2θ), 22.107–22.591°C (2θ) and 34.908–35.075°C (2θ) reflections were assigned to reflection assigned to the (11̅0) crystallographic plane, (110) crystallographic plane, amorphous phase, (020) crystallographic plane and (004) crystallographic [37].

The X-ray diffraction pattern generated to evaluate the crystallinity of the cellulose samples in Figure 1 showed a peak at 2θ = 22.591 and 22.308°C for Guarea thompsonii of 425–599 μm and 600–849 μm of size classifications. These distinct peaks obtained for the XRD of the samples is an indication that the cellulose are crystalline in nature.

The diffraction peak of cellulose shown around 2θ = 12.414–14.755°C was assigned to the crystalline plane of (11̅0) for cellulose type I and II. Moreover, it is interesting that cellulose showed the doublet in the intensity of the main peaks (2θ = 20.2–20.4°C) which were also assigned to the crystalline planes of (110) for cellulose type I and II. This shows that mixture of cellulose I and II has been the most stable structure of technical relevance and can be produced by two processes: Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose… DOI: http://dx.doi.org/10.5772/intechopen.82849

#### Figure 1.

3.2 FTIR spectroscopy measurement

3.3 Scanning Electron MicroscopeMeasurement

cellulose samples.

Cellulose

ogy of the cellulose obtained.

talline arrangements [40, 41].

4.1 X-ray diffraction (XRD) of cellulose

4. Results

graphic [37].

48

crystalline in nature.

Fourier transform infrared (FTIR) spectroscopy is a mature analytical technique employed to examine the microscopic area of a materials. FTIR spectra of powder samples of cellulose were obtained using a Thermo Nicolet 5700 FTIR spectrometer (Nicolet, Madison, WI, USA). The Spectra were acquired over the range 500– 4000 cm<sup>1</sup> at a resolution of 2 cm<sup>1</sup> for samples in pellet form prepared by mixing 1.0 mg of powder samples with 200.0 mg KBr spectroscopic grade. The spectra obtained were used for rapid information about the chemical structure of the

The morphological characterization of composite materials can be investigated by the Scanning Electron Microscopy (SEM). It is a popular and powerful technique for imaging the surface of a material (surface topology, morphology and chemical composition) [39]. The image resolution depends on the property of the electron and the electron probe interaction with the specimen. SEM analysis was performed on the isolated cellulose obtained of the two size classifications using FEI NOVA 200 NanoSEM equipment (FEI Company, Hillsboro Oregon, USA) with an accelerating voltage of up to 30 kV and a resolution of up to 1 nm to observe the morphol-

X-ray diffraction (XRD) is a method generally used to determine the crystallinity of materials, interplanar distances etc. The free hydroxyl groups present in the cellulose macromolecules are likely to be involved in a number of intramolecular and intermolecular hydrogen bonds, which may give rise to various ordered crys-

In order to evaluate and determine the intensities of the diffraction bands, establish the crystalline and amorphous areas and determine the crystallite sizes of the cellulose, the X-ray diffractogram (Figure 1) was adopted. The crystallographic planes from the diffractogram are labeled according to the cellulose structure. The diffractograms showed that 12.414–14.755°C (2θ), 16.910–17.127°C (2θ), 18.01°C (2θ), 22.107–22.591°C (2θ) and 34.908–35.075°C (2θ) reflections were assigned to reflection assigned to the (11̅0) crystallographic plane, (110) crystallographic plane, amorphous phase, (020) crystallographic plane and (004) crystallo-

The X-ray diffraction pattern generated to evaluate the crystallinity of the cellulose samples in Figure 1 showed a peak at 2θ = 22.591 and 22.308°C for Guarea thompsonii of 425–599 μm and 600–849 μm of size classifications. These distinct peaks obtained for the XRD of the samples is an indication that the cellulose are

The diffraction peak of cellulose shown around 2θ = 12.414–14.755°C was assigned to the crystalline plane of (11̅0) for cellulose type I and II. Moreover, it is interesting that cellulose showed the doublet in the intensity of the main peaks (2θ = 20.2–20.4°C) which were also assigned to the crystalline planes of (110) for cellulose type I and II. This shows that mixture of cellulose I and II has been the most stable structure of technical relevance and can be produced by two processes:

XRD of isolated cellulose obtained for different size classifications for Guarea thompsonii (a) 425–599 μm (b) 600–849 μm.

regeneration (solubilization and recrystallization) and mercerization (aqueous sodium hydroxide treatments) [27].

From this result, it can be concluded that alkali treatment in pretreatment process led to the change of cellulose allomorph from type I; the native cellulose found in nature, to type I and II; the regenerated cellulose which is the most stable crystalline form. Moreover, the acid hydrolysis which removed the amorphous region out from the cellulose led to re-crystallization was the main cause to obtain the obvious peaks of doublet intensity at 2θ = 20.2–20.4°C.

#### 4.1.1 Investigation of the crystallites structure of cellulose by XRD

The average dimensions of the elementary crystallites perpendicular to the (110), ̅ (110) and (020) crystallographic planes of the mixture of cellulose I and cellulose II with amorphous can be calculated using the Scherrer's equation, by measuring the full widths at half maximum (FWHM) of the different diffraction peaks, assuming that the finite size of crystallites dominate the broadening of the X-ray reflections. These values have to be considered as a lower bound since instrumental broadening and possible imperfections of the crystal lattice are neglected by the method.

The results obtained from the XRD profiles of samples in Figure 1 are presented in Tables 1 and 2. In this, only the length perpendicular to the (020) plane could be calculated since the (11̅0) and (110) reflections in the XRD profile overlapped each other. An average crystallite length of about 1.742 nm and 1.748 nm were obtained Guarea thompsonii of 425 μm 599 μm and 600 μm 800 μm size classifications.

The inter-planar spacing (d-spacing) values of the cellulose spectra for most prominent peak with crystal plane of preferred orientation along the (020) were 3.933 Å m and 3.982 Å m for Guarea thompsonii of 425–599 μm and 600–849 μm


#### Table 1.

Band position (2θ) and d-spacing of crystalline cellulose of Guarea thompsonii.


Table 2.

Parameters obtained from the XRD analysis of the cellulose samples of Guarea thompsonii.

respectively. Other values of inter planar spacing for the remaining crystallographic planes were depicted in Table 1.

The crystalline interior chains W for the isolated samples were calculated by the fraction of cellulose chains contained in the interior of the crystallites. It was estimated as 0.12 for the two samples isolated in Table 2. This indicated that the proportion of crystallite interior chains, W, is similar for both samples examined.

Table 2 showed the calculated Z- values for the two size classifications (Guarea thompsonii). The values of the estimated isolated cellulose obtained wereless than zero (Z < 0). This shows that the cellulose samples belong to Iβ (monoclinic) dominant.

> could be ascribed to CH2 wagging vibrations in the cellulose while the absorption at 1200 cm<sup>1</sup> belongs to the C▬O▬H in-plane bending at C-6 [44, 45]. The band peak at 1610 cm<sup>1</sup> can be assigned as OH bending due to absorbed water because the OH bending mode is strongly perturbed by bound water [46]. Strong peaks at

FTIR spectra of isolated cellulose of different size classifications for Guarea thompsonii (a) 425–599 μm

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose…

C▬O stretching at C–6 [45]. Finally, the absorbance peak observed at 899 cm<sup>1</sup> was assigned to the symmetric C▬O▬C stretching of β (1⟶4)-glycosidic linkage.

The Scanning Electron Microscopy (SEM) was an effective method for investigating the morphological characteristics of the composites. Figures 3 and 4 show

As shown in Figures 3 and 4, SEM images of the isolated cellulose of two samples depicted strings of fibers. This was in agreement with other authors' find-

the SEM image of Guarea thompsonii of isolated cellulose obtained.

SEM image of isolated cellulose for Guarea thompsonii of 425–599 μm size classifications.

ings, although the length of the fiber may differ [47–52].

are indicative of C▬O stretching at C-3, C▬C stretching and

1020 and 1090 cm<sup>1</sup>

Figure 2.

Figure 3.

51

(b) 600–849 μm.

4.3 Scanning Electron Microscopy (SEM)

DOI: http://dx.doi.org/10.5772/intechopen.82849

The degree of cellulose crystallinity is one of the most important crystalline structure parameters. The crystallinity index (CrI) calculated according to [33] showed that the crystallinity of cellulose obtained for 425–599 μm size classification was higher than that obtained for 600 μm to 849 μm size classification. The CrI value are 56.89 and 54.09% for Guarea thompsonii cellulose obtained from different size classifications of 425–599 μm and 600–849 μm, respectively. In contrast, 60.4% for Eucalpyptus grandis and 62.6% for Pinus taeda were also recorded in a study of structural characteristics and thermal properties of native cellulose [41]. This high percentage in crystallinity index might be associated with the reduction in the corresponding amorphous state of the material due to the probable dissociation of the bonds as a result of pulping. This can also due to significant increase in surface area-to-volume ratio of the molecules, and with the crystalline size of the samples reducing to nanoscale. The difference in the values obtained may be due to the chemical treatments for purification and crystalline or amorphous standard [42]. Moreover, high crystallinity index is associated to increase stiffness, rigidity and strength of the isolated cellulose obtained. As a result, sample with 425–599 μm size classifications has high potential mechanical property and reinforcing capability than sample with 600–849 μm size classifications [43].

#### 4.2 Fourier infra-red spectroscopy (FTIR) of cellulose

Figure 2 shows the functional groups and the band positions for the isolated cellulose prepared by Fourier Infra-red Spectroscopy (FTIR).

Two main absorbance regions were pronounced by the samples considered. The absorbance regions were in the range of approximately 1110–870 cm <sup>1</sup> and 3630–2960 cm<sup>1</sup> wave number. The intensities regions were high in 425–599 μm size classifications than 600–849 μm due to the surface to volume ratio of the atom exposed to the FTIR machine.

The strong dominant broad peaks in the region are obtained from 3630 to 2960 cm<sup>1</sup> which is commonly observed for hydrogen. The absorption around 3320 cm<sup>1</sup> corresponds to the vibration of H- bonded OH groups while a peak near 2890 cm<sup>1</sup> is assigned to C-H stretching vibration. These inter- and intra- molecular hydrogen bonds in the cellulose has a strong influence on the physical and mechanical properties of the cellulose. The band near 1160 cm<sup>1</sup> is representative of the anti-symmetric bridge stretching of C▬O▬C groups. The band near 1300 cm<sup>1</sup>

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose… DOI: http://dx.doi.org/10.5772/intechopen.82849

#### Figure 2.

respectively. Other values of inter planar spacing for the remaining crystallographic

Classification (μm) L(020) (nm) Cr.I W Z-Values 425–599 1.750 56.89 0.12 2.229 600–849 1.749 54.09 0.12 8.428

The degree of cellulose crystallinity is one of the most important crystalline structure parameters. The crystallinity index (CrI) calculated according to [33] showed that the crystallinity of cellulose obtained for 425–599 μm size classification was higher than that obtained for 600 μm to 849 μm size classification. The CrI value are 56.89 and 54.09% for Guarea thompsonii cellulose obtained from different size classifications of 425–599 μm and 600–849 μm, respectively. In contrast, 60.4% for Eucalpyptus grandis and 62.6% for Pinus taeda were also recorded in a study of structural characteristics and thermal properties of native cellulose [41]. This high percentage in crystallinity index might be associated with the reduction in the corresponding amorphous state of the material due to the probable dissociation of the bonds as a result of pulping. This can also due to significant increase in surface area-to-volume ratio of the molecules, and with the crystalline size of the samples reducing to nanoscale. The difference in the values obtained may be due to the chemical treatments for purification and crystalline or amorphous standard [42]. Moreover, high crystallinity index is associated to increase stiffness, rigidity and strength of the isolated cellulose obtained. As a result, sample with 425–599 μm size classifications has high potential mechanical property and reinforcing capability

Figure 2 shows the functional groups and the band positions for the isolated

absorbance regions were in the range of approximately 1110–870 cm <sup>1</sup> and 3630–2960 cm<sup>1</sup> wave number. The intensities regions were high in 425–599 μm size classifications than 600–849 μm due to the surface to volume ratio of the atom

The strong dominant broad peaks in the region are obtained from 3630 to 2960 cm<sup>1</sup> which is commonly observed for hydrogen. The absorption around 3320 cm<sup>1</sup> corresponds to the vibration of H- bonded OH groups while a peak near 2890 cm<sup>1</sup> is assigned to C-H stretching vibration. These inter- and intra- molecular hydrogen bonds in the cellulose has a strong influence on the physical and mechanical properties of the cellulose. The band near 1160 cm<sup>1</sup> is representative of the anti-symmetric bridge stretching of C▬O▬C groups. The band near 1300 cm<sup>1</sup>

Two main absorbance regions were pronounced by the samples considered. The

than sample with 600–849 μm size classifications [43].

4.2 Fourier infra-red spectroscopy (FTIR) of cellulose

exposed to the FTIR machine.

50

cellulose prepared by Fourier Infra-red Spectroscopy (FTIR).

fraction of cellulose chains contained in the interior of the crystallites. It was estimated as 0.12 for the two samples isolated in Table 2. This indicated that the proportion of crystallite interior chains, W, is similar for both samples examined. Table 2 showed the calculated Z- values for the two size classifications (Guarea thompsonii). The values of the estimated isolated cellulose obtained wereless than zero (Z < 0). This shows that the cellulose samples belong to Iβ (monoclinic)

Parameters obtained from the XRD analysis of the cellulose samples of Guarea thompsonii.

The crystalline interior chains W for the isolated samples were calculated by the

planes were depicted in Table 1.

dominant.

Table 2.

Cellulose

FTIR spectra of isolated cellulose of different size classifications for Guarea thompsonii (a) 425–599 μm (b) 600–849 μm.

could be ascribed to CH2 wagging vibrations in the cellulose while the absorption at 1200 cm<sup>1</sup> belongs to the C▬O▬H in-plane bending at C-6 [44, 45]. The band peak at 1610 cm<sup>1</sup> can be assigned as OH bending due to absorbed water because the OH bending mode is strongly perturbed by bound water [46]. Strong peaks at 1020 and 1090 cm<sup>1</sup> are indicative of C▬O stretching at C-3, C▬C stretching and C▬O stretching at C–6 [45]. Finally, the absorbance peak observed at 899 cm<sup>1</sup> was assigned to the symmetric C▬O▬C stretching of β (1⟶4)-glycosidic linkage.

#### 4.3 Scanning Electron Microscopy (SEM)

The Scanning Electron Microscopy (SEM) was an effective method for investigating the morphological characteristics of the composites. Figures 3 and 4 show the SEM image of Guarea thompsonii of isolated cellulose obtained.

As shown in Figures 3 and 4, SEM images of the isolated cellulose of two samples depicted strings of fibers. This was in agreement with other authors' findings, although the length of the fiber may differ [47–52].

Figure 3. SEM image of isolated cellulose for Guarea thompsonii of 425–599 μm size classifications.

Figure 4. SEM image of isolated cellulose for Guarea thompsonii of 600–899 μm size classifications.

#### 4.4 Energy dispersive X-ray diffraction (EDX)

Energy dispersive X-ray diffraction (EDX) attached with SEM was used for elemental analysis of isolated cellulose. The EDX spectra (as shown in Figures 5 and 6) peaks correspond to the energy levels for which the carbon (C), oxygen (O),

chlorine (Cl), and Sodium (Na) were identified with carbon having the highest percentage among the elements observed in the spectra. The elemental compositions for the samples with size classifications 425–599 μm were 58.9 wt % carbon, 40.7 wt % oxygen and 0.4 wt % sodium and 55.2 wt % carbon, 44.0 wt % oxygen, 0.5 wt % chlorine and 0.3 wt % sodium for 600–899 μm. The impurities present could have been due to the NaClO2 that was used in the bleaching process.

spectrum of isolated cellulose for Guarea thompsoniiof 600–899 μmsize classifications.

(1) SEM image of isolated cellulose for Guarea thompsonii of 600–899 μm size classifications; and (2) EDX

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose…

DOI: http://dx.doi.org/10.5772/intechopen.82849

Wood dusts from two size classifications were isolated from XRD, FTIR, SEM and EDX. The isolated cellulose obtained is the mixture of cellulose I and II and amorphous with fiber-like shape. The two celluloses examined has a preferred orientations along the (020) plane for the most prominent peaks with a crystallinity index of 56.89% for size range 425–599 μm and 54.09% for size range 600–849 μm. The crystallinity index is high in 425–599 μm size classifications compare to 600– 849 μm. This indicates that the strength properties is higher in 425–599 μm size classification and have reinforcement ability than 600–849 μm. It is important to

5. Conclusion

53

Figure 6.

(1) SEM image of isolated cellulose for Guarea thompsonii of 425–599 μm size classifications; and (2) EDX spectrum of isolated cellulose for Guarea thompsoniiof 425–599 μm size classifications.

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose… DOI: http://dx.doi.org/10.5772/intechopen.82849

Figure 6.

4.4 Energy dispersive X-ray diffraction (EDX)

Figure 4.

Cellulose

Figure 5.

52

Energy dispersive X-ray diffraction (EDX) attached with SEM was used for elemental analysis of isolated cellulose. The EDX spectra (as shown in Figures 5 and 6) peaks correspond to the energy levels for which the carbon (C), oxygen (O),

(1) SEM image of isolated cellulose for Guarea thompsonii of 425–599 μm size classifications; and (2) EDX

spectrum of isolated cellulose for Guarea thompsoniiof 425–599 μm size classifications.

SEM image of isolated cellulose for Guarea thompsonii of 600–899 μm size classifications.

(1) SEM image of isolated cellulose for Guarea thompsonii of 600–899 μm size classifications; and (2) EDX spectrum of isolated cellulose for Guarea thompsoniiof 600–899 μmsize classifications.

chlorine (Cl), and Sodium (Na) were identified with carbon having the highest percentage among the elements observed in the spectra. The elemental compositions for the samples with size classifications 425–599 μm were 58.9 wt % carbon, 40.7 wt % oxygen and 0.4 wt % sodium and 55.2 wt % carbon, 44.0 wt % oxygen, 0.5 wt % chlorine and 0.3 wt % sodium for 600–899 μm. The impurities present could have been due to the NaClO2 that was used in the bleaching process.

#### 5. Conclusion

Wood dusts from two size classifications were isolated from XRD, FTIR, SEM and EDX. The isolated cellulose obtained is the mixture of cellulose I and II and amorphous with fiber-like shape. The two celluloses examined has a preferred orientations along the (020) plane for the most prominent peaks with a crystallinity index of 56.89% for size range 425–599 μm and 54.09% for size range 600–849 μm. The crystallinity index is high in 425–599 μm size classifications compare to 600– 849 μm. This indicates that the strength properties is higher in 425–599 μm size classification and have reinforcement ability than 600–849 μm. It is important to

note that size classifications played a major role on the crystallinity index on the sample examined which is a basic factor that determine how high the mechanical properties is in a material.

References

[1] Belgacem MN, Gandini A. The surface modification of cellulose fibres for use as reinforcing elements in composite materials. Composite Interfaces. 2005;12(1–2):41-75. DOI:

DOI: http://dx.doi.org/10.5772/intechopen.82849

[8] Sun JX, Sun XF, Zhao H, Sun RC. Isolation and characterization of cellulose from sugarcane bagasse. Polymer Degradation and Stability. 2004;84:331-339. DOI: 10.1016/j. polymdegradstab.2004.02.008

[9] Klemm D, Philipp B, Heinze T, Heinze U, Wagenknecht W.

[10] Sèbe G, Ham-Pichavant F, Ibarboure E, Koffi ALC, Tingaut P.

Supramolecular structure characterization of cellulose II nanowhiskers produced by acid hydrolysis of cellulose I substrates. Biomacromolecules. 2012;13(2):570-578.

DOI: 10.1021/bm201777j

[11] Varrot A, Macdonald J, Stick RV, Pell P, Gilbert HJ, Davies GJ. Distortion of a cellobio-derived isofagomine highlights the potential conformational itinerary of inverting β –glu-cosidases. Chemical Communications. 2003:

[12] Bidlack J, Malone M, Benson R. Molecular structure and component integration of secondary cell walls in plants. Proceedings of the Oklahoma Academy of Science. 1992;72:51-56

[13] Sehaqui H, Zhou Q, Ikkala O, Berglund LA. Strong and tough cellulose nanopaper with high specific surface area and porosity. Biomacromolecules. 2012;12(10):3638-3644. DOI: 10.1021/

[14] Hon DNS, Shiraishi N. Wood and Cellulosic Chemistry. New York:

[15] Ishikawa A, Sugiyama J, Okano T. Fine Structure and Tensile Properties of

VCH; 1998

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose…

946-947

bm2008907

M. Dekker; 1991

Comprehensive Cellulose Chemistry, Volume 1, Fundamentals and Analytical Methods. Weinheim, Germany: Wiley-

[2] Oluyamo SS, Adekoya MA. Effect of dynamic compression on the thermal conductivities of selected wood products of different particle sizes. International Research Journal of Pure and Applied Physics. 2015;3(1):22-29

10.1163/1568554053542188

[3] Adekoya MA, Oluyamo SS,

1.906-917

0903011417

pp. 43-60

55

2014;104:223-230

Oluwasina OO, Popoola AI. Structural characterization and solid state properties of thermal insulating cellulose materials of different size classifications. BioResource. 2018;13(1): 906-917. DOI: 10.15376/biores13.

[4] Oluyamo SS, Bello OR. Particle sizes and thermal insulation properties of some selected wood materials for solar device applications. IOSR-JAP. 2014; 6(2):54-58. DOI: 10.9790/4861-

[5] Hosemann R. Crystallinity in high polymers, especially fibres. Polymer. 1962;3:349-392. DOI: 10.1016/ 0032-3861(62) 90093-9

[6] Varshney VK, Naithani S. Chemical functionalization of cellulose derived from nonconventional sources. In: Kalia S et al., editors. Cellulose Fibers: Bioand Nano-Polymer Composites. Berlin Heidelberg: Springer-Verlag; 2011.

[7] Trache D, Donnot A, Khimeche K, Benelmir R, Brosse N. Physico-chemical properties and thermal stability of microcrystalline cellulose isolated from alfa fibres. Carbohydrate Polymers.

### Acknowledgements

We express our gratitude to the Material and Engineering Research Institute (MERI), Sheffield Hallam University (UK) for their support and excellent work done during the analyses of the powder material; The Federal University of Technology, Akure, Nigeria and Edo University, Iyamho, Nigeria are also appreciated for their support during the preparation of the samples.

### Conflict of interest

No conflict of interest.

### Author details

Oluyamo Sunday Samuel1 and Adekoya Mathew Adefusika1,2\*

1 Condensed Matter and Statistical Physics Research Unit, Department of Physics, Federal University of Technology, Akure, Nigeria

2 Department of Physics, Edo University Iyamho, Edo State, Nigeria

\*Address all correspondence to: mathewadekoya14@gmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose… DOI: http://dx.doi.org/10.5772/intechopen.82849

#### References

note that size classifications played a major role on the crystallinity index on the sample examined which is a basic factor that determine how high the mechanical

We express our gratitude to the Material and Engineering Research Institute (MERI), Sheffield Hallam University (UK) for their support and excellent work done during the analyses of the powder material; The Federal University of Technology, Akure, Nigeria and Edo University, Iyamho, Nigeria are also appreciated

for their support during the preparation of the samples.

Oluyamo Sunday Samuel1 and Adekoya Mathew Adefusika1,2\*

2 Department of Physics, Edo University Iyamho, Edo State, Nigeria

\*Address all correspondence to: mathewadekoya14@gmail.com

Federal University of Technology, Akure, Nigeria

provided the original work is properly cited.

1 Condensed Matter and Statistical Physics Research Unit, Department of Physics,

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

properties is in a material.

Cellulose

Acknowledgements

Conflict of interest

Author details

54

No conflict of interest.

[1] Belgacem MN, Gandini A. The surface modification of cellulose fibres for use as reinforcing elements in composite materials. Composite Interfaces. 2005;12(1–2):41-75. DOI: 10.1163/1568554053542188

[2] Oluyamo SS, Adekoya MA. Effect of dynamic compression on the thermal conductivities of selected wood products of different particle sizes. International Research Journal of Pure and Applied Physics. 2015;3(1):22-29

[3] Adekoya MA, Oluyamo SS, Oluwasina OO, Popoola AI. Structural characterization and solid state properties of thermal insulating cellulose materials of different size classifications. BioResource. 2018;13(1): 906-917. DOI: 10.15376/biores13. 1.906-917

[4] Oluyamo SS, Bello OR. Particle sizes and thermal insulation properties of some selected wood materials for solar device applications. IOSR-JAP. 2014; 6(2):54-58. DOI: 10.9790/4861- 0903011417

[5] Hosemann R. Crystallinity in high polymers, especially fibres. Polymer. 1962;3:349-392. DOI: 10.1016/ 0032-3861(62) 90093-9

[6] Varshney VK, Naithani S. Chemical functionalization of cellulose derived from nonconventional sources. In: Kalia S et al., editors. Cellulose Fibers: Bioand Nano-Polymer Composites. Berlin Heidelberg: Springer-Verlag; 2011. pp. 43-60

[7] Trache D, Donnot A, Khimeche K, Benelmir R, Brosse N. Physico-chemical properties and thermal stability of microcrystalline cellulose isolated from alfa fibres. Carbohydrate Polymers. 2014;104:223-230

[8] Sun JX, Sun XF, Zhao H, Sun RC. Isolation and characterization of cellulose from sugarcane bagasse. Polymer Degradation and Stability. 2004;84:331-339. DOI: 10.1016/j. polymdegradstab.2004.02.008

[9] Klemm D, Philipp B, Heinze T, Heinze U, Wagenknecht W. Comprehensive Cellulose Chemistry, Volume 1, Fundamentals and Analytical Methods. Weinheim, Germany: Wiley-VCH; 1998

[10] Sèbe G, Ham-Pichavant F, Ibarboure E, Koffi ALC, Tingaut P. Supramolecular structure characterization of cellulose II nanowhiskers produced by acid hydrolysis of cellulose I substrates. Biomacromolecules. 2012;13(2):570-578. DOI: 10.1021/bm201777j

[11] Varrot A, Macdonald J, Stick RV, Pell P, Gilbert HJ, Davies GJ. Distortion of a cellobio-derived isofagomine highlights the potential conformational itinerary of inverting β –glu-cosidases. Chemical Communications. 2003: 946-947

[12] Bidlack J, Malone M, Benson R. Molecular structure and component integration of secondary cell walls in plants. Proceedings of the Oklahoma Academy of Science. 1992;72:51-56

[13] Sehaqui H, Zhou Q, Ikkala O, Berglund LA. Strong and tough cellulose nanopaper with high specific surface area and porosity. Biomacromolecules. 2012;12(10):3638-3644. DOI: 10.1021/ bm2008907

[14] Hon DNS, Shiraishi N. Wood and Cellulosic Chemistry. New York: M. Dekker; 1991

[15] Ishikawa A, Sugiyama J, Okano T. Fine Structure and Tensile Properties of Ramie Fibers in the Crystalline Form of Cellulose I, II and III1. Vol. 81. Wood Research; 1994. pp. 16-18

[16] Oh SY, Dong IY, Shin Y, Hwan CK, Hak YK, Yong SC, et al. Crystalline structure analysis of cellulose treated with sodium hydroxide and carbon dioxide by means of X-ray diffraction and FTIR spectroscopy. Carbohydrate Research. 2005;340:2376-2391. DOI: 10.1016/j.carres.2005.007

[17] Matheus P, Vinícios P, Ademir JZ. Structural Characteristics and Thermal Properties of Native Cellulose. Rijeka, Croatia: Intech Open Science; 2013. pp. 45-68

[18] Wicklein B, Salazar-Alvarez G. Functional hybrids based on biogenic nanofibrils and inorganic nanomaterials. Journal of Materials Chemistry A. 2013;1: 5469-5478. DOI: 10.1039/C3TA01690K

[19] Pérez S, Mazeau K. Conformations, structures, and morphologies of celluloses. In: Dimitriu S, editor. Polysaccharides: Structural Diversity and Functional Versatility. New York: Marcel Dekker, Inc.; 2005. pp. 41-68

[20] Zugenmaier P. Crystalline Cellulose and Cellulose Derivatives: Characterization and Structures. Springer Series in Wood Science. Berlin, Heidelberg: Springer-Verlag; Cellulose; 2008. pp. 101-174

[21] Al-Zuhair S. The effect of crystallinity of cellulose on the rate of reducing sug-ars production by heterogeneous enzymatic hydrolysis. Bioresource Technology. 2008;99: 4078-4085

[22] Andersson S, Serimaa R, Paakkari T, Saranpaa P, Pesonen E. Crystallinity of wood and the size of cellulose crystallites in Norway spruce (Picea abies) WJ. Wood Science. 2003;49:531-537. DOI: 10.1007/s10086-003-0518-x

[23] Cao Y, Tan HM. Study on crystal structures of enzymehydrolyzedcellulosic materials by X-ray diffraction. Enzyme and Microbial Technology. 2005;36:314-317

[31] Park S, Baker JO, Himmel ME, Parilla PA, Johnson DK. Cellulose crystallinity index: Measurement techniques and their impact on interpreting cellulase performance. Biotechnology for Biofuels. -2010;3(1): 10. DOI: 10.1186/1754-6834-3-10

DOI: http://dx.doi.org/10.5772/intechopen.82849

Influence on crystallite size. Polymer Degradation and Stability. 2010;95: 778-781. DOI: 10.1016/j.polymdegradstab.

[39] Azzaoui K, Mejdoubi E, Lamhamdi A, Jodeh S, Hamed O, Berrabah M, et al. Preparation and characterization of biodegradable nanocomposites derived from carboxymethyl cellulose and hydroxyapatite. Carbohydrate Polymers. 2017;167:59-69. DOI: 10.1016/j.carbpol.2017.02.092

[40] Popescu MC, Popescu CM, Lisa G, Sakata Y. Evaluation of morphological and chemical aspects of different wood species by spectroscopy and thermal methods. Journal of Molecular Structure. 2011;988:65-72. DOI: 10.1016/j.molstruc.2010.12.004

[41] Poletto M, Pistor V, Zattera AJ. Structural characteristics and thermal properties of native cellulose. In: Van de Ven T, Gdbout L, editors. Cellulose-Fundamental Aspects. Rijeka, Croatia: Intech Open Science; 2013.

[42] Gümüskaya E, Usta M, Kirci H. The effects of various pulping conditions on crystalline structure of cellulose in cotton linters. Polymer Degradation and Stability. 2003;81(3):559-564. DOI: 10.1016/S0141-3910(03)00157-5

[43] Johar N, Ahmad I, Dufresne A. Extraction, preparation and

10.1016/j.indcrop.2011.12.016

[44] Cao Y, Tan HM. Structural characterization of cellulose with enzymatic treatment. Journal of

characterization of celluloses fibres and nanocrystals from rice husk. Industrial Crops and Products. 2012;37:93-99. DOI:

Molecular Structure. 2004;705:189-193. DOI: 10.1016/j.molstruc.2004.07.010

[45] Liu CF, Xu F, Sun JX, Ren JL,

Physicochemical characterization of

Curling S, Sun RC, et al.

2010.02.009

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose…

pp. 45-68.4

[32] Thygesen A, Oddershede J, Lilholt H, Thomsen AB, Stahl K. On the determination of crystallinity and cellulose content in plant fibres. Cellulose. -2005;12(6):563-576. DOI:

10.1007/s10570-005-9001-8

[33] Segal L, Creely JJ, Martin AE, Conrad CM. An empirical method for estimating the degree of crystallinity of

native cellulose using the X-ray diffractometer. Textile Research Journal. 1959;29(10):786-794. DOI: 10.1177/004051755902901003

[34] Agarwal UP, Reiner RS, Ralph SA. Cellulose I crystallinity determination using FT–Raman spectroscopy: Univariateand multivariate methods. Cellulose. 2010;17(4):721-733. DOI: 10.1007/s10570-010-9420-z

[35] Jaya H, Omar MF, Akil HA, Ahmad ZA, Zulkepli NN. Effect of particle size on mechanical properties of sawdusthigh density polyethylene composites under various strain rate. BioResources. 2016;11(3):6489-6504. DOI: 10.15376/

[36] Oluyamo SS, Aramide TM, Adekoya MA, Famutimi OF. Variation of bulk and particle thermal properties of some selected wood materials for solar device applications. IOSRJournalofApplied Physics (IOSR-JAP). 2017;9(3):14-17. DOI: 10.9790/4861-0903011417

[37] Wada M, Okano T. Localization of Iα and Iβ phases in algal cellulose revealed by acid treatments. Cellulose. 2001;8:183-188. DOI: 10.1023/A:

[38] Kim UJ, Eom SH, Wada M. Thermal decomposition of native cellulose:

biores.11.3.6489-6504

1013196220602

57

[24] Lavoine N, Desloges I, Dufresne A, Bras J. Microfibrillated cellulose - its barrier properties and applications in cellulosic materials: A review. Carbohydrate Polymers. 2012;90(2): 735-764. DOI: 10.1016/j.carbpol. 2012.05.026

[25] Hall M, Bansal P, Lee JH, Realff MJ, Bommarius AS. Cellulose crystallinity-a key predictor of the enzymatic hydrolysis rate. The FEBS Journal. 2010; 277:1571-1582

[26] Ryu D, Lee SB, Tassinari T. Effect of crystallinity of cellulose on enzymatic– hydrolysis kinetics. Abstracts of Papers of the American Chemical Society. 1981; 182:58-60

[27] Moon RJ, Martini A, Nairn J, Simonsen J, Youngblood J. Cellulose nanomaterials review: Structure, properties and nanocomposites. Chemical Society Revision. 2011;40: 3941-3994

[28] Bansal P, Hall M, Realff MJ, Lee JH, Bommarius AS. Multivariate statistical analysis of X-ray data from cellulose: A new method to determine degree of crystallinity and predict hydrolysis rates. Bioresource Technology. 2010; 101:4461-4471

[29] Driemeier C, Calligaris GA. Theoretical and experimental developments for accurate determination of crystallinity of cellulose I materials. Journal of Applied Crystallography. 2011;44:184-192

[30] French AD, Cintron MS. Cellulose polymorphy, crystallite size, and the Segal crystallinity index. Cellulose. 2013;20:583-588. DOI: 10.1007/ s10570-012-9833-y

Influence of Size Classifications on the Structural and Solid-State Characterization of Cellulose… DOI: http://dx.doi.org/10.5772/intechopen.82849

[31] Park S, Baker JO, Himmel ME, Parilla PA, Johnson DK. Cellulose crystallinity index: Measurement techniques and their impact on interpreting cellulase performance. Biotechnology for Biofuels. -2010;3(1): 10. DOI: 10.1186/1754-6834-3-10

Ramie Fibers in the Crystalline Form of Cellulose I, II and III1. Vol. 81. Wood

[23] Cao Y, Tan HM. Study on crystal

hydrolyzedcellulosic materials by X-ray diffraction. Enzyme and Microbial Technology. 2005;36:314-317

[24] Lavoine N, Desloges I, Dufresne A, Bras J. Microfibrillated cellulose - its barrier properties and applications in cellulosic materials: A review. Carbohydrate Polymers. 2012;90(2): 735-764. DOI: 10.1016/j.carbpol.

[25] Hall M, Bansal P, Lee JH, Realff MJ, Bommarius AS. Cellulose crystallinity-a

hydrolysis rate. The FEBS Journal. 2010;

[26] Ryu D, Lee SB, Tassinari T. Effect of crystallinity of cellulose on enzymatic– hydrolysis kinetics. Abstracts of Papers of the American Chemical Society. 1981;

[28] Bansal P, Hall M, Realff MJ, Lee JH, Bommarius AS. Multivariate statistical analysis of X-ray data from cellulose: A new method to determine degree of crystallinity and predict hydrolysis rates. Bioresource Technology. 2010;

[29] Driemeier C, Calligaris GA. Theoretical and experimental developments for accurate determination of crystallinity of cellulose I materials. Journal of Applied Crystallography. 2011;44:184-192

[30] French AD, Cintron MS. Cellulose polymorphy, crystallite size, and the Segal crystallinity index. Cellulose. 2013;20:583-588. DOI: 10.1007/

key predictor of the enzymatic

[27] Moon RJ, Martini A, Nairn J, Simonsen J, Youngblood J. Cellulose nanomaterials review: Structure, properties and nanocomposites. Chemical Society Revision. 2011;40:

structures of enzyme-

2012.05.026

277:1571-1582

182:58-60

3941-3994

101:4461-4471

s10570-012-9833-y

[16] Oh SY, Dong IY, Shin Y, Hwan CK, Hak YK, Yong SC, et al. Crystalline structure analysis of cellulose treated with sodium hydroxide and carbon dioxide by means of X-ray diffraction and FTIR spectroscopy. Carbohydrate Research. 2005;340:2376-2391. DOI:

[17] Matheus P, Vinícios P, Ademir JZ. Structural Characteristics and Thermal Properties of Native Cellulose. Rijeka, Croatia: Intech Open Science; 2013.

[18] Wicklein B, Salazar-Alvarez G. Functional hybrids based on biogenic nanofibrils and inorganic nanomaterials. Journal of Materials Chemistry A. 2013;1: 5469-5478. DOI: 10.1039/C3TA01690K

[19] Pérez S, Mazeau K. Conformations,

[20] Zugenmaier P. Crystalline Cellulose

Springer Series in Wood Science. Berlin, Heidelberg: Springer-Verlag; Cellulose;

crystallinity of cellulose on the rate of reducing sug-ars production by heterogeneous enzymatic hydrolysis. Bioresource Technology. 2008;99:

[22] Andersson S, Serimaa R, Paakkari T, Saranpaa P, Pesonen E. Crystallinity of wood and the size of cellulose crystallites in Norway spruce (Picea abies) WJ. Wood Science. 2003;49:531-537. DOI:

structures, and morphologies of celluloses. In: Dimitriu S, editor. Polysaccharides: Structural Diversity and Functional Versatility. New York: Marcel Dekker, Inc.; 2005. pp. 41-68

and Cellulose Derivatives: Characterization and Structures.

[21] Al-Zuhair S. The effect of

10.1007/s10086-003-0518-x

2008. pp. 101-174

4078-4085

56

Research; 1994. pp. 16-18

Cellulose

10.1016/j.carres.2005.007

pp. 45-68

[32] Thygesen A, Oddershede J, Lilholt H, Thomsen AB, Stahl K. On the determination of crystallinity and cellulose content in plant fibres. Cellulose. -2005;12(6):563-576. DOI: 10.1007/s10570-005-9001-8

[33] Segal L, Creely JJ, Martin AE, Conrad CM. An empirical method for estimating the degree of crystallinity of native cellulose using the X-ray diffractometer. Textile Research Journal. 1959;29(10):786-794. DOI: 10.1177/004051755902901003

[34] Agarwal UP, Reiner RS, Ralph SA. Cellulose I crystallinity determination using FT–Raman spectroscopy: Univariateand multivariate methods. Cellulose. 2010;17(4):721-733. DOI: 10.1007/s10570-010-9420-z

[35] Jaya H, Omar MF, Akil HA, Ahmad ZA, Zulkepli NN. Effect of particle size on mechanical properties of sawdusthigh density polyethylene composites under various strain rate. BioResources. 2016;11(3):6489-6504. DOI: 10.15376/ biores.11.3.6489-6504

[36] Oluyamo SS, Aramide TM, Adekoya MA, Famutimi OF. Variation of bulk and particle thermal properties of some selected wood materials for solar device applications. IOSRJournalofApplied Physics (IOSR-JAP). 2017;9(3):14-17. DOI: 10.9790/4861-0903011417

[37] Wada M, Okano T. Localization of Iα and Iβ phases in algal cellulose revealed by acid treatments. Cellulose. 2001;8:183-188. DOI: 10.1023/A: 1013196220602

[38] Kim UJ, Eom SH, Wada M. Thermal decomposition of native cellulose:

Influence on crystallite size. Polymer Degradation and Stability. 2010;95: 778-781. DOI: 10.1016/j.polymdegradstab. 2010.02.009

[39] Azzaoui K, Mejdoubi E, Lamhamdi A, Jodeh S, Hamed O, Berrabah M, et al. Preparation and characterization of biodegradable nanocomposites derived from carboxymethyl cellulose and hydroxyapatite. Carbohydrate Polymers. 2017;167:59-69. DOI: 10.1016/j.carbpol.2017.02.092

[40] Popescu MC, Popescu CM, Lisa G, Sakata Y. Evaluation of morphological and chemical aspects of different wood species by spectroscopy and thermal methods. Journal of Molecular Structure. 2011;988:65-72. DOI: 10.1016/j.molstruc.2010.12.004

[41] Poletto M, Pistor V, Zattera AJ. Structural characteristics and thermal properties of native cellulose. In: Van de Ven T, Gdbout L, editors. Cellulose-Fundamental Aspects. Rijeka, Croatia: Intech Open Science; 2013. pp. 45-68.4

[42] Gümüskaya E, Usta M, Kirci H. The effects of various pulping conditions on crystalline structure of cellulose in cotton linters. Polymer Degradation and Stability. 2003;81(3):559-564. DOI: 10.1016/S0141-3910(03)00157-5

[43] Johar N, Ahmad I, Dufresne A. Extraction, preparation and characterization of celluloses fibres and nanocrystals from rice husk. Industrial Crops and Products. 2012;37:93-99. DOI: 10.1016/j.indcrop.2011.12.016

[44] Cao Y, Tan HM. Structural characterization of cellulose with enzymatic treatment. Journal of Molecular Structure. 2004;705:189-193. DOI: 10.1016/j.molstruc.2004.07.010

[45] Liu CF, Xu F, Sun JX, Ren JL, Curling S, Sun RC, et al. Physicochemical characterization of cellulose from perennial ryegrass leaves (Lolium perenne). Carbohydrate Research. 2006;341:2677-2687. DOI: 10.1016/j.carres.2006.07.008

[46] Oh SY, Yoo D, Shin Y, Seo G. FTIR analysis of cellulose treated with sodium hydroxide and carbon dioxide. Carbohydrate Research. 2005;340: 417-428. DOI: 10.1016/j.carres. 2004.11.027

[47] El-Sakhawy M, Hassan ML. Physical and mechanical properties of microcrystalline cellulose prepared from agricultural residues. Carbohydrate Polymer. 2007;67(1):1-10. DOI: 10.1016/j.carbpol.2006.04.009

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[49] Ibrahim MM, Agblevor AF, El-Zawawy W. K: Isolation and characterization of cellulose and lignin from steam-exploded lignocellulosic biomass. BioResources. 2010;5(1): 397-418. DOI: 10.15376/biores. 5.1.397-418

[50] Pereira PHP, Voorwald HCJ, Cioffi MOH, Mulinari DR, Da Luz SM, Da Silva MLCP. Sugarcane bagasse pulping and bleaching: Thermal and chemical characterization. BioResources. 2011; 6(3):2471-2482

[51] Morgado DL, Frollini E. Thermal decomposition of mercerized linter cellulose and its acetates obtained from a homogeneous reaction. Polímeros. 2011;21(2):111-117. DOI: 10.1590/ S0104-14282011005000025

[52] Oluwasina O, Lajide L, Owolabi B. Microcrystalline cellulose from plant waste through sodium hydroxideanthraquinone-ethanol pulping. Bio

Resources. 2014;9(4):6166-6192. DOI: 10.15376/biores.9.4.6166-6192

**59**

implants, biofuels, consumables

**1. Introduction**

**Chapter 4**

**Abstract**

Applications

An Update on Overview of

Cellulose, Its Structure and

*Praveen Kumar Gupta, Shreeya Sai Raghunath,* 

*Vidhya Shree, Chandrananthi Chithananthan,* 

*Deepali Venkatesh Prasanna, Priyadharsini Venkat,* 

*Shreya Choudhary, Krithika Surender and Keerthana Geetha*

Cellulose (C6H10O5)n is one of the most ubiquitous organic polymers on the planet. It is a significant structural component of the primary cell wall of green plants, various forms of algae and oomycetes. It is a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1 → 4) linked d-glucose units. There are various extraction procedures for cellulose developed by using different processes like oxidation, etherification and esterification which convert the prepared celluloses in to cellulose derivatives. Since it is a non-toxic, bio-degradable polymer with high tensile and compressive strength, it has widespread use in various fields such as nanotechnology, pharmaceutical industry, food industry, cosmetics, textile and paper industry, drug-delivery systems in treating cancer and other diseases. Micro-crystalline cellulose in particular is among the most frequently used cellulose derivatives in the food, cosmetics, pharma industry, etc. and is an important excipient due to its binding and tableting properties, characterized by its plasticity and cohesiveness when wet. Bacterial cellulose's high dispensability, tasteless and odourless nature provides it with lot of industrial applications. Currently, about half of the waste produced in India contains about 50% cellulose which can be used productively. This chapter deals with the chemistry of cellulose, its extraction and its properties which help various industries to make the most of it.

**Keywords:** properties, chemistry, types, microcrystalline cellulose, cellulose nanocrystals, cellulose nanofibres, extraction, characterization, NMR, SEM, FTIR, BJH, biomedical applications, pharmaceutical applications, renewable energy applications, waste management, drug delivery, wound healing, scaffolding,

Cellulose is the most abundant biopolymer available in nature, since it is one of the major components of the cell walls of most of the plants [1]. It is a homopolymer of anhydroglucose, with the glucose residues linked in a ß-1,4 fashion [2]. Cell walls of plant cells attribute their mechanical strength to cellulose. Cellulose owes its

**Chapter 4**

cellulose from perennial ryegrass leaves

Resources. 2014;9(4):6166-6192. DOI:

10.15376/biores.9.4.6166-6192

[46] Oh SY, Yoo D, Shin Y, Seo G. FTIR analysis of cellulose treated with sodium

[47] El-Sakhawy M, Hassan ML. Physical

microcrystalline cellulose prepared from agricultural residues. Carbohydrate Polymer. 2007;67(1):1-10. DOI: 10.1016/j.carbpol.2006.04.009

Carboxymethylated cellulose hydrogel; sorption behavior and characterization. Nature and Science. 2010;8(8):244-256.

[50] Pereira PHP, Voorwald HCJ, Cioffi MOH, Mulinari DR, Da Luz SM, Da Silva MLCP. Sugarcane bagasse pulping and bleaching: Thermal and chemical characterization. BioResources. 2011;

[51] Morgado DL, Frollini E. Thermal decomposition of mercerized linter cellulose and its acetates obtained from a homogeneous reaction. Polímeros. 2011;21(2):111-117. DOI: 10.1590/ S0104-14282011005000025

[52] Oluwasina O, Lajide L, Owolabi B. Microcrystalline cellulose from plant waste through sodium hydroxideanthraquinone-ethanol pulping. Bio

(Lolium perenne). Carbohydrate Research. 2006;341:2677-2687. DOI: 10.1016/j.carres.2006.07.008

hydroxide and carbon dioxide. Carbohydrate Research. 2005;340: 417-428. DOI: 10.1016/j.carres.

and mechanical properties of

[48] Adel AM, Abou-Youssef H, El-Gendy AA, Nada AM.

DOI: 10.7537/marsnsj080810.29

[49] Ibrahim MM, Agblevor AF, El-Zawawy W. K: Isolation and characterization of cellulose and lignin from steam-exploded lignocellulosic biomass. BioResources. 2010;5(1): 397-418. DOI: 10.15376/biores.

2004.11.027

Cellulose

5.1.397-418

6(3):2471-2482

58

## An Update on Overview of Cellulose, Its Structure and Applications

*Praveen Kumar Gupta, Shreeya Sai Raghunath, Deepali Venkatesh Prasanna, Priyadharsini Venkat, Vidhya Shree, Chandrananthi Chithananthan, Shreya Choudhary, Krithika Surender and Keerthana Geetha*

#### **Abstract**

Cellulose (C6H10O5)n is one of the most ubiquitous organic polymers on the planet. It is a significant structural component of the primary cell wall of green plants, various forms of algae and oomycetes. It is a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1 → 4) linked d-glucose units. There are various extraction procedures for cellulose developed by using different processes like oxidation, etherification and esterification which convert the prepared celluloses in to cellulose derivatives. Since it is a non-toxic, bio-degradable polymer with high tensile and compressive strength, it has widespread use in various fields such as nanotechnology, pharmaceutical industry, food industry, cosmetics, textile and paper industry, drug-delivery systems in treating cancer and other diseases. Micro-crystalline cellulose in particular is among the most frequently used cellulose derivatives in the food, cosmetics, pharma industry, etc. and is an important excipient due to its binding and tableting properties, characterized by its plasticity and cohesiveness when wet. Bacterial cellulose's high dispensability, tasteless and odourless nature provides it with lot of industrial applications. Currently, about half of the waste produced in India contains about 50% cellulose which can be used productively. This chapter deals with the chemistry of cellulose, its extraction and its properties which help various industries to make the most of it.

**Keywords:** properties, chemistry, types, microcrystalline cellulose, cellulose nanocrystals, cellulose nanofibres, extraction, characterization, NMR, SEM, FTIR, BJH, biomedical applications, pharmaceutical applications, renewable energy applications, waste management, drug delivery, wound healing, scaffolding, implants, biofuels, consumables

#### **1. Introduction**

Cellulose is the most abundant biopolymer available in nature, since it is one of the major components of the cell walls of most of the plants [1]. It is a homopolymer of anhydroglucose, with the glucose residues linked in a ß-1,4 fashion [2]. Cell walls of plant cells attribute their mechanical strength to cellulose. Cellulose owes its

structural properties to the fact that it can retain a semi-crystalline state of aggregation even in an aqueous environment, which is unusual for a polysaccharide [3, 4].

As far as cellulose based products are concerned, paperboard and paper are the most commonly used ones [5]. Smaller amounts of cellulose when processed under appropriate conditions, can be converted to a wide variety of derivatives, these can be used in manufacture of few commercial products like cellophane and rayon [6].

Since cellulose is a homopolymer of a glucose derivative, it is a great source of fermentable sugar. It is cultivated in the form of energy crops for the production of ethanol, ethers, acetic acid, etc. Besides energy requirements the industrial demands of cellulose are fulfilled by wood pulp and cotton crops [7].

Cellulose also fulfils the dietary requirements of some animals, particularly ruminants and termite, they can digest cellulose with help of symbiotic microorganisms present in their gut, while some organisms secrete a group of enzymes called cellulases to aid the degradation of cellulose molecules [8]. Human beings are unable to digest cellulose due to lack of cellulases, thus cellulose acts as a hydrophilic bulking agent for faeces and potentially aids in defecation [9].

#### **2. Overview**

Among the various raw materials which nature has placed at our disposal for industrial purposes, cellulose has from time immemorial occupied a prominent position. Its abundance is attributed to the constant photosynthetic cycles taking place in higher plants, which can synthesize around 1011 ± 1012 tons of cellulose in a rather pure form. Since time immemorial it has served mankind either as a construction material or as a versatile starting material for chemical reactions for the production of artificial cellulose based threads and biofilms as well as for production of a variety of stable cellulose derivatives which are used for various industrial and domestic applications [10]. Cellulose was used for various biochemical conversions even before its polymeric nature was recognized and well understood. In the process of recognizing and understanding its polymeric structure, it led to the discovery of nitrocellulose, synthesis of organo-soluble cellulose acetate and the preparation of Schweizer's reagent (first cellulose solvent). Another area of great interest was nanocellulose, the nanostructure of cellulose has proven to be advantageous because of its applications in a variety of fields [11, 12].

Due to such great economical significance of tree cellulose, the current scientific focus is more towards cellulose biosynthesis as it is still not well understood [13]. Most of the recent findings concerning the molecular mechanism of cellulose biosynthesis in higher plants resulted from research in model herbaceous plants and fibre crops and have been reviewed recently. All these aspects trigger a researchers' curiosity and makes them want to dig deeper and unveil other properties and applications of cellulose.

#### **3. Chemistry of cellulose**

The Cellulose is made up of a d-glucose unit at one end and a C4-OH group, the non-reducing end, while the terminating group is C1-OH, the reducing end with aldehyde structure. Some technical celluloses contain extra carbonyl and carboxy groups, like the bleached wood pulp. The molecular structure is responsible for its significant properties: Chirality, hydrophilicity, degradability and chemical variability due to high reactivity from the donor group—OH. The superior hydrogen bonds add crystalline fibre structures to cellulose. **Figure 1** presents the four

**61**

**Figure 2.**

**Figure 1.**

**4. Properties of cellulose**

*Major pathways of formation of cellulose [14].*

*An Update on Overview of Cellulose, Its Structure and Applications*

different pathways which determine the major processing routes. The most famous and highly used pathway is the manufacture of cellulose from plants. It is established that cellulose is found in its purest form from the seed hairs of cotton. The wood cellulose, on the other hand forms a composite with lignin and other polysaccharides, which is further separated by large scale chemical pulping and purification processes. Cellulose can be derived from algae, some specific bacteria, and fungi, apart from most plants. The supramolecular structures are used for research on cellulose structures, reactivity, and crystallinity with further note on development of biomaterials and new substances. Cyanobacteria are known to biosynthesize cellulose for nearly 3.5 billion years [15]. The first synthesis of cellulose in vitro is reported as the cellucellulase—cellulose formation by catalyzed cellobiosyl fluoride and the chemosynthesis was processed in a ring opening polymerization of the d-glucose moieties [16]. A lot of research is ongoing in the field and study of cellulose over the past decade. The structure and properties of cellulose are quintes-

sential to perform modifications and processing of cellulose on the whole.

*Molecular structure of cellulose (n = DP, degree of polymerization) [14].*

The structure of cellulose has been constantly a subject requiring intensive research as it is formed by the hydrogen bonds between the network of hydroxy groups [17]. The progress was for more than a 100 years of intensive development on structure analysis methods like electron microscopy, X-ray diffraction and high

*DOI: http://dx.doi.org/10.5772/intechopen.84727*

*An Update on Overview of Cellulose, Its Structure and Applications DOI: http://dx.doi.org/10.5772/intechopen.84727*

*Cellulose*

**2. Overview**

applications of cellulose.

**3. Chemistry of cellulose**

structural properties to the fact that it can retain a semi-crystalline state of aggregation even in an aqueous environment, which is unusual for a polysaccharide [3, 4]. As far as cellulose based products are concerned, paperboard and paper are the most commonly used ones [5]. Smaller amounts of cellulose when processed under appropriate conditions, can be converted to a wide variety of derivatives, these can be used in manufacture of few commercial products like cellophane and rayon [6]. Since cellulose is a homopolymer of a glucose derivative, it is a great source of fermentable sugar. It is cultivated in the form of energy crops for the production of ethanol, ethers, acetic acid, etc. Besides energy requirements the industrial

Cellulose also fulfils the dietary requirements of some animals, particularly ruminants and termite, they can digest cellulose with help of symbiotic microorganisms present in their gut, while some organisms secrete a group of enzymes called cellulases to aid the degradation of cellulose molecules [8]. Human beings are unable to digest cellulose due to lack of cellulases, thus cellulose acts as a hydrophilic

Among the various raw materials which nature has placed at our disposal for industrial purposes, cellulose has from time immemorial occupied a prominent position. Its abundance is attributed to the constant photosynthetic cycles taking place in higher plants, which can synthesize around 1011 ± 1012 tons of cellulose in a rather pure form. Since time immemorial it has served mankind either as a construction material or as a versatile starting material for chemical reactions for the production of artificial cellulose based threads and biofilms as well as for production of a variety of stable cellulose derivatives which are used for various industrial and domestic applications [10]. Cellulose was used for various biochemical conversions even before its polymeric nature was recognized and well understood. In the process of recognizing and understanding its polymeric structure, it led to the discovery of nitrocellulose, synthesis of organo-soluble cellulose acetate and the preparation of Schweizer's reagent (first cellulose solvent). Another area of great interest was nanocellulose, the nanostructure of cellulose has proven to be advanta-

Due to such great economical significance of tree cellulose, the current scientific focus is more towards cellulose biosynthesis as it is still not well understood [13]. Most of the recent findings concerning the molecular mechanism of cellulose biosynthesis in higher plants resulted from research in model herbaceous plants and fibre crops and have been reviewed recently. All these aspects trigger a researchers' curiosity and makes them want to dig deeper and unveil other properties and

The Cellulose is made up of a d-glucose unit at one end and a C4-OH group, the non-reducing end, while the terminating group is C1-OH, the reducing end with aldehyde structure. Some technical celluloses contain extra carbonyl and carboxy groups, like the bleached wood pulp. The molecular structure is responsible for its significant properties: Chirality, hydrophilicity, degradability and chemical variability due to high reactivity from the donor group—OH. The superior hydrogen bonds add crystalline fibre structures to cellulose. **Figure 1** presents the four

demands of cellulose are fulfilled by wood pulp and cotton crops [7].

bulking agent for faeces and potentially aids in defecation [9].

geous because of its applications in a variety of fields [11, 12].

**60**

**Figure 1.** *Major pathways of formation of cellulose [14].*

different pathways which determine the major processing routes. The most famous and highly used pathway is the manufacture of cellulose from plants. It is established that cellulose is found in its purest form from the seed hairs of cotton. The wood cellulose, on the other hand forms a composite with lignin and other polysaccharides, which is further separated by large scale chemical pulping and purification processes. Cellulose can be derived from algae, some specific bacteria, and fungi, apart from most plants. The supramolecular structures are used for research on cellulose structures, reactivity, and crystallinity with further note on development of biomaterials and new substances. Cyanobacteria are known to biosynthesize cellulose for nearly 3.5 billion years [15]. The first synthesis of cellulose in vitro is reported as the cellucellulase—cellulose formation by catalyzed cellobiosyl fluoride and the chemosynthesis was processed in a ring opening polymerization of the d-glucose moieties [16]. A lot of research is ongoing in the field and study of cellulose over the past decade. The structure and properties of cellulose are quintessential to perform modifications and processing of cellulose on the whole.

#### **4. Properties of cellulose**

The structure of cellulose has been constantly a subject requiring intensive research as it is formed by the hydrogen bonds between the network of hydroxy groups [17]. The progress was for more than a 100 years of intensive development on structure analysis methods like electron microscopy, X-ray diffraction and high

**Figure 2.** *Molecular structure of cellulose (n = DP, degree of polymerization) [14].*

**Figure 3.**

*The crystal structures of cellulose I and II: (a) projection of the unit cell along the a-b plane and (b) projection of UC parallel to (100) lattice plane, cellulose I and (010) lattice plane, cellulose II [14].*

resolution solid state NMR spectroscopy. The complete detailed analysis is required for the procedures of synthetic reactions and cellulose based manmade products with extensive applications. The structure of cellulose as depicted in **Figure 2** consists of hydroxyl groups of β-1,4-glucan cellulose at C2, C3 and C6. The CH2OH group is positioned relative to the C4 and C5 bonds along with a shear relativity with O5–C5 bonds. The solid state is equally likely to be represented in the crystalline (high order) and amorphous (low order). The crystal structure in particular is determined by the X-ray diffraction using a monoclinic unit cell which is made up of two cellulose chains in a parallel orientation and two fold screw axis [18]. The investigations with respect to the electron microbeam diffraction, combined X-ray and neutron diffraction have clearly indicated that the cellulose crystalline structures have a triclinic and monoclinic unit cell. The schematic representations of the Iβ crystal structure, in **Figure 3**, indicate the two intramolecular chain-stiffening hydrogen bonds. The recent researches on the Iβ crystal structure have different H-bonds and different conformations of neighbouring chains. The thermodynamically stable cellulose II can occur in other forms of crystal structures and is the most stable form of cellulose. The cellulose I can be treated with aqueous sodium hydroxide to form cellulose II.

#### **5. Types of cellulose**

#### **5.1 Bacterial cellulose**

Although cellulose is mainly produced by plants, many bacteria, especially those belonging to the genus *Gluconacetobacter are involved in the production of a* very peculiar form of cellulose with mechanical and structural properties that can be exploited in numerous applications. Bacterial cellulose are usually produced by *Gluconacetobacter hansenii* UCP1619 using the Hestrin-Schramm (HS) medium. But there are few limitations associated with bacterial cellulose like the production cost is high, use of expensive culture media, poor yields, downstream processing, and operating costs. Bacterial cellulose can also be produced by bacteria from genera *Sarcina*, and *Agrobacterium* [19]. *Bacterial cellulose produced by aerobic bacteria has unique physiochemical properties compared to plant cellulose* [20].

**63**

**Figure 4.**

*Different sources of cellulose extraction.*

*An Update on Overview of Cellulose, Its Structure and Applications*

Cellulose acetate is an important ester of cellulose. Cellulose acetate can be used for great varies of applications like for films, membranes or fibres, depending on the way it has been processed. A special field for using cellulose acetate is the

Ethylcellulose (EC) is a derivative of cellulose in which some of the hydroxyl groups on the repeating anhydroglucose units are modified into ethyl ether groups, largely called as non-ionic ethyl ether of cellulose. Ethylcellulose (EC) based microencapsulated drug delivery systems are being studied to achieve extended

Hydroxypropyl cellulose (HPC) is one of the derivatives of cellulose which is soluble in both water and organic solvent. It can be used as a lubricant. It can also be used for the treatment of keratoconjunctivitis sicca, corneal erosions neuroparalytic keratitis etc. It is also used as a lubricant for patients having artificial

Cellulose is one of the most abundant biomass materials in nature possessing some promising properties. In our work, let us look into the various procedures involved in extracting cellulose from different sources. The sources available are many which can be broadly classified into Agro-waste, Domestic-waste (and other means such as wood, plant and paper). The processes involved include usual chemical procedures like alkaline extraction, bleaching, acid hydrolysis and chlorination. The final products can be characterized by using techniques like thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electronic microscopy (SEM). Purified cellulose can be obtained successfully using the above mentioned procedures. In our study, we will be concentrating on the extraction of cellulose from

synthesis of porous, spherical particles, so called cellulose beads [21].

drug release and to protect the core substance from degradation [22].

*DOI: http://dx.doi.org/10.5772/intechopen.84727*

**5.4 Hydroxypropyl cellulose (HPC)**

**6. Extraction and characterization of cellulose**

agricultural residues and plants [26–28] (**Figure 4**).

**5.2 Cellulose acetate**

**5.3 Ethylcellulose**

eye [23–25].

#### **5.2 Cellulose acetate**

*Cellulose*

**Figure 3.**

resolution solid state NMR spectroscopy. The complete detailed analysis is required for the procedures of synthetic reactions and cellulose based manmade products with extensive applications. The structure of cellulose as depicted in **Figure 2** consists of hydroxyl groups of β-1,4-glucan cellulose at C2, C3 and C6. The CH2OH group is positioned relative to the C4 and C5 bonds along with a shear relativity with O5–C5 bonds. The solid state is equally likely to be represented in the crystalline (high order) and amorphous (low order). The crystal structure in particular is determined by the X-ray diffraction using a monoclinic unit cell which is made up of two cellulose chains in a parallel orientation and two fold screw axis [18]. The investigations with respect to the electron microbeam diffraction, combined X-ray and neutron diffraction have clearly indicated that the cellulose crystalline structures have a triclinic and monoclinic unit cell. The schematic representations of the Iβ crystal structure, in **Figure 3**, indicate the two intramolecular chain-stiffening hydrogen bonds. The recent researches on the Iβ crystal structure have different H-bonds and different conformations of neighbouring chains. The thermodynamically stable cellulose II can occur in other forms of crystal structures and is the most stable form of cellulose. The cellulose I can be treated with aqueous sodium hydroxide to form

*The crystal structures of cellulose I and II: (a) projection of the unit cell along the a-b plane and (b) projection* 

*of UC parallel to (100) lattice plane, cellulose I and (010) lattice plane, cellulose II [14].*

Although cellulose is mainly produced by plants, many bacteria, especially those belonging to the genus *Gluconacetobacter are involved in the production of a* very peculiar form of cellulose with mechanical and structural properties that can be exploited in numerous applications. Bacterial cellulose are usually produced by *Gluconacetobacter hansenii* UCP1619 using the Hestrin-Schramm (HS) medium. But there are few limitations associated with bacterial cellulose like the production cost is high, use of expensive culture media, poor yields, downstream processing, and operating costs. Bacterial cellulose can also be produced by bacteria from genera *Sarcina*, and *Agrobacterium* [19]. *Bacterial cellulose produced by aerobic bacteria has unique physiochemical properties compared to* 

**62**

cellulose II.

**5. Types of cellulose**

**5.1 Bacterial cellulose**

*plant cellulose* [20].

Cellulose acetate is an important ester of cellulose. Cellulose acetate can be used for great varies of applications like for films, membranes or fibres, depending on the way it has been processed. A special field for using cellulose acetate is the synthesis of porous, spherical particles, so called cellulose beads [21].

#### **5.3 Ethylcellulose**

Ethylcellulose (EC) is a derivative of cellulose in which some of the hydroxyl groups on the repeating anhydroglucose units are modified into ethyl ether groups, largely called as non-ionic ethyl ether of cellulose. Ethylcellulose (EC) based microencapsulated drug delivery systems are being studied to achieve extended drug release and to protect the core substance from degradation [22].

#### **5.4 Hydroxypropyl cellulose (HPC)**

Hydroxypropyl cellulose (HPC) is one of the derivatives of cellulose which is soluble in both water and organic solvent. It can be used as a lubricant. It can also be used for the treatment of keratoconjunctivitis sicca, corneal erosions neuroparalytic keratitis etc. It is also used as a lubricant for patients having artificial eye [23–25].

#### **6. Extraction and characterization of cellulose**

Cellulose is one of the most abundant biomass materials in nature possessing some promising properties. In our work, let us look into the various procedures involved in extracting cellulose from different sources. The sources available are many which can be broadly classified into Agro-waste, Domestic-waste (and other means such as wood, plant and paper). The processes involved include usual chemical procedures like alkaline extraction, bleaching, acid hydrolysis and chlorination. The final products can be characterized by using techniques like thermogravimetric analysis (TGA), infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electronic microscopy (SEM). Purified cellulose can be obtained successfully using the above mentioned procedures. In our study, we will be concentrating on the extraction of cellulose from agricultural residues and plants [26–28] (**Figure 4**).

**Figure 4.** *Different sources of cellulose extraction.*

#### **6.1 Extraction of cellulose from agricultural residues**

#### *6.1.1 Extraction of cellulose from sugarcane bagasse*

Sugarcane bagasse (SCB) is a key agricultural residue which has grown to be the point of interest in recent times. The extraction of cellulose from SCB was investigated using steam explosion and xylanase based environmentally friendly pretreatment for reducing chemical bleaching and to determine the characteristics of cellulose from sugarcane bagasse. SCB is a low value agriculture residue and about 40–50% of bagasse is the glucose polymer cellulose. There are several approaches to pretreat lignocellulosic materials to extract cellulose such as steam explosion, solvent extraction and alkaline treatment.

#### *6.1.1.1 Methodology*

Cellulose is extracted from SCB by using steam explosion and xylanase pretreatment and bleaching process. The dried SCB treated with steam explosion at a pressure 13 bar (195°C) for 15 minutes to obtain steam exploded SCB fibres. Then, the steam exploded SCB is treated with 20 μg of xylanase using fibre to liquor ratio of 1:10 for 1 hour at 50°C under constant agitation. Then, dried steam exploded SCB is treated with xylanase (fibre to liquor ratio of 1:10) and then bleached with 0.7% sodium chlorite (NaClO2) adjusted to a pH of 4 by the addition of weak acetic acid at 70°C for 1 hour. Sodium chlorite and acetic acid at the same loading were added to the reaction every 1 hour till the cellulose turns white. The cellulose fibres thus obtained would then filtrated, washed with distilled water until the pH of water neutral and dried at 55°C for 24 hours. The steam explosion process includes saturating the dry material with steam at elevated pressure and temperature followed by sudden release of pressure, resulting in substantial resistance of degraded lignin fragments, facilitates the release of lignin, which is then readily available for further bleaching and thereby increases the efficiency of the bleaching process Thus, the use of enzymes to treat pulp before applying chemical bleaching help to reduce chemical required in bleaching stage, breakdown of lignocellulosic structure, hydrolysis of the hemicelluloses fraction, depolymerization of the lignin components and defibrillization. In terms of bleaching treatments, chlorine-based chemicals were typically used for bleaching process resulting in chemical hazard released into environmental. Xylanases are glycosyl hydrolase that can catalyse the hydrolysis of β-1, 4-glycosidic bonds in xylan by means of double displacement mechanical reaction. This treatment improves accessibility of bleaching chemical to the pulp by decreasing diffusion [29] (**Table 1**).

#### *6.1.2 Extraction of cellulose from rice husk*

Rice is the most cultivated cereal crop in the world. Rice husk is a major agrowaste that is generated in huge quantities. It accounts for 20% of the 600 million tons of paddy produced worldwide. People often dispose the rice husk waste using open burning which is an environmental threat causing damage to the land and the surrounding area in which it is disposed. This rice husk can be put into best use by exploitation of its cellulose content. Rice husk comprises of 33% cellulose, 26% hemicellulose, and 7% lignin. Thus, the use of rice husk as the primary source for producing cellulose fibres and nanocrystals is efficient. The strategy is to extract cellulose fibres from the rice husk using alkali and bleaching treatments.

**65**

*An Update on Overview of Cellulose, Its Structure and Applications*

**Fibres α-Cellulose** 

*6.1.2.2 Preparation of cellulose nanocrystals from rice husk*

Sodium hydroxide (99% purity) is used for alkaline treatment. Sodium chlorite, acetic acid and NaOH are used as bleaching agents while sulphuric acid is used for

**(in %)**

Untreated SCB 44.5 21.8 22.5 Steam-exploded SCB 65.7 9.9 18.3 Steam exploded with xylanase treated 66.3 8.8 18.6 Bleached fibre 89.3 4.3 1.5

*Extraction and characterization of cellulose from sugarcane bagasse by using environmental friendly method [29].*

**Hemicellulose (in %)**

**Lignin (in %)**

1.**Treatment with alkali**: Cellulose is purified by treating with Alkali to remove lignin and hemicellulose on or after rice husk grits. The pulverised rice husk is preserved through an alkali solution (4% by weight of NaOH). The combination is poured into a plump bottom flask and action is performed at reflux temperature intended for 2 hours. The solid is formerly filtered and carry away numerous times by means of distilled water. This treatment is frequent thrice.

completed by totalling a buffer solution of acetic acid, aqueous chlorite (1.7% by weightiness) and purified water at reflux (by means of a silicon emollient soak at 100–130°C) for 4 hours. The assortment is then permitted to cool and the additional distilled liquid is filtered. The bleaching procedure is performed four periods.

3.**Acid hydrolysis:** The acid hydrolysis action is performed on the fibres subsequently alkali action and decolourising at a temperature of 50°C by means of

non-stop stirring. The fibre content varieties from 4 to 6% by heaviness. The hydrolysed substantial is eroded by centrifugation at 10000 rpm at 10°C for 10 minutes. This centrifugation stage is repeated many times before the suspension is dialyzed in contradiction of purified water for several days until persistent pH in the range of 5–6 is attained. The subsequent suspension is formerly sonicated for 30 minutes previously it is frozen for additional use [30].

This extraction method involves use of Bamboo fibres as a raw material for cellulose extraction. The chemicals used to produce cellulose nanofibres are toluene, ethanol, hydrogen peroxide, acetic acid glacial, titanium (IV) oxide, and sodium

hydroxide. All the chemicals used here are of analytical grade.

of preheated sulphuric acid intended for 40 minutes underneath

2.**Bleaching process:** Subsequent the alkali action, bleaching progression is

*DOI: http://dx.doi.org/10.5772/intechopen.84727*

*6.1.2.1 Methodology*

10.0 mol L<sup>−</sup><sup>1</sup>

**6.2 Extraction of cellulose from plants**

*6.2.1 Extraction of cellulose from bamboo*

hydrolysis.

**Table 1.**


*An Update on Overview of Cellulose, Its Structure and Applications DOI: http://dx.doi.org/10.5772/intechopen.84727*

**Table 1.**

*Cellulose*

**6.1 Extraction of cellulose from agricultural residues**

Sugarcane bagasse (SCB) is a key agricultural residue which has grown to be the point of interest in recent times. The extraction of cellulose from SCB was investigated using steam explosion and xylanase based environmentally friendly pretreatment for reducing chemical bleaching and to determine the characteristics of cellulose from sugarcane bagasse. SCB is a low value agriculture residue and about 40–50% of bagasse is the glucose polymer cellulose. There are several approaches to pretreat lignocellulosic materials to extract cellulose such as steam explosion,

Cellulose is extracted from SCB by using steam explosion and xylanase pretreatment and bleaching process. The dried SCB treated with steam explosion at a pressure 13 bar (195°C) for 15 minutes to obtain steam exploded SCB fibres. Then, the steam exploded SCB is treated with 20 μg of xylanase using fibre to liquor ratio of 1:10 for 1 hour at 50°C under constant agitation. Then, dried steam exploded SCB is treated with xylanase (fibre to liquor ratio of 1:10) and then bleached with 0.7% sodium chlorite (NaClO2) adjusted to a pH of 4 by the addition of weak acetic acid at 70°C for 1 hour. Sodium chlorite and acetic acid at the same loading were added to the reaction every 1 hour till the cellulose turns white. The cellulose fibres thus obtained would then filtrated, washed with distilled water until the pH of water neutral and dried at 55°C for 24 hours. The steam explosion process includes saturating the dry material with steam at elevated pressure and temperature followed by sudden release of pressure, resulting in substantial resistance of degraded lignin fragments, facilitates the release of lignin, which is then readily available for further bleaching and thereby increases the efficiency of the bleaching process Thus, the use of enzymes to treat pulp before applying chemical bleaching help to reduce chemical required in bleaching stage, breakdown of lignocellulosic structure, hydrolysis of the hemicelluloses fraction, depolymerization of the lignin components and defibrillization. In terms of bleaching treatments, chlorine-based chemicals were typically used for bleaching process resulting in chemical hazard released into environmental. Xylanases are glycosyl hydrolase that can catalyse the hydrolysis of β-1, 4-glycosidic bonds in xylan by means of double displacement mechanical reaction. This treatment improves accessibility of bleaching chemical to the pulp by

Rice is the most cultivated cereal crop in the world. Rice husk is a major agrowaste that is generated in huge quantities. It accounts for 20% of the 600 million tons of paddy produced worldwide. People often dispose the rice husk waste using open burning which is an environmental threat causing damage to the land and the surrounding area in which it is disposed. This rice husk can be put into best use by exploitation of its cellulose content. Rice husk comprises of 33% cellulose, 26% hemicellulose, and 7% lignin. Thus, the use of rice husk as the primary source for producing cellulose fibres and nanocrystals is efficient. The strategy is to extract

cellulose fibres from the rice husk using alkali and bleaching treatments.

*6.1.1 Extraction of cellulose from sugarcane bagasse*

solvent extraction and alkaline treatment.

decreasing diffusion [29] (**Table 1**).

*6.1.2 Extraction of cellulose from rice husk*

*6.1.1.1 Methodology*

**64**

*Extraction and characterization of cellulose from sugarcane bagasse by using environmental friendly method [29].*

#### *6.1.2.1 Methodology*

Sodium hydroxide (99% purity) is used for alkaline treatment. Sodium chlorite, acetic acid and NaOH are used as bleaching agents while sulphuric acid is used for hydrolysis.

#### *6.1.2.2 Preparation of cellulose nanocrystals from rice husk*


#### **6.2 Extraction of cellulose from plants**

#### *6.2.1 Extraction of cellulose from bamboo*

This extraction method involves use of Bamboo fibres as a raw material for cellulose extraction. The chemicals used to produce cellulose nanofibres are toluene, ethanol, hydrogen peroxide, acetic acid glacial, titanium (IV) oxide, and sodium hydroxide. All the chemicals used here are of analytical grade.

#### *6.1.2.3 Methodology*


#### *6.1.2.4 Characterization of cellulose extracted from bamboo*

After extraction of cellulose, it is generally characterized by using the following techniques:

**67**

**Figure 5.**

*intensity at 1514 cm<sup>−</sup><sup>1</sup>*

*the lignin was well removed by chemical process [30, 32].*

*An Update on Overview of Cellulose, Its Structure and Applications*

were to be taken at a resolution of 4 cm<sup>−</sup><sup>1</sup>

1.**Fourier transform infrared spectroscopy (FTIR)**: The infrared spectra obtained using a FTIR Spectrometer model IRAFFINITY-1 CE. The spectra

tion changes in GBF were investigated by FTIR spectroscopy (**Figure 5**).

3.**Barrett-Joyner-Halenda (BJH) analysis:** In order to do BJH analysis the bamboo fibre sample is dried for 24 hours at 70°C and inserted into a capillary tube. The outgas had an approximately 7 hour duration with final outgas temperature of 350°C. After outgas process, the sample was analysed using Nova Quantachrome 4200e automated gas sorption instrument for 1.5 hours across a wide range of relative pressures at constant temperature (77 K) using liquid nitrogen (**Figure 6**).

4.**Thermogravimetric analysis (TGA):** Dynamic thermogravimetric measurements were performed using a Shimadzu DTG 60H instrument. The temperature programs for dynamic tests was run from ambient temperature 25–700°C. All measurements was made under a nitrogen flow (20mL/min),

The chemical conformation of rice husk at individual phase of action is originate to be giving to the approaches conveyed by the Technical Association of Pulp and Paper Industry (TAPPI). The cellulose and hemicellulose contents are retrieved conferring to TAPPI standard T203 OS-74 though the lignin content is restrained according to TAPPI normal T222 OS-83. The silica ash content is calculated by

*Comparative differences of FTIR peaks into green bamboo fibre (GBF) and cellulose fibre (CF). The peak* 

*ring of lignin. Yet, the cellulose fibre did not show the C═C stretching at that region. This is an indication that* 

 *from the spectrum of the GBF is credited to the C═C stretching vibration in the aromatic* 

while keeping a constant heating rate of 10°Cmin<sup>−</sup><sup>1</sup>

*6.1.2.5 Characterization of cellulose extracted from rice husk fibres*

crucible with a pinhole (**Figure 7**).

2.**Scanning electron microscopy (SEM):** The bamboo fibre samples was vacuum-dried for 24 hours at 70°C, pressed onto a carbon tape adhered to a sample holder surface, and sputtered with titanium. Imaging of each sample was done using Hitachi M-3030 scanning electron microscope. All images were taken at an accelerating voltage of 5 kV with a magnification of 1500 time [33].

ple. The transmittance range of the scans was 600–4000 cm<sup>−</sup><sup>1</sup>

, with a total of 60 scans for each sam-

and using an aluminium

. The composi-

*DOI: http://dx.doi.org/10.5772/intechopen.84727*

*Cellulose*

*6.1.2.3 Methodology*

(GBF).

1.**Bamboo fibre preparation:** Green bamboo Culm of 1 m length is prepared. It is then ground using a planner machine to produce small chips and powder form excluding the internodes. This chips and powder mixture is put into an oven at 70°C for 72 hours to dry. The oven dried sample is ground and then sieved using 600μm size sieve. The 600μm mesh size fibres are used for the synthesis of cellulose fibre. This sample is then labelled as green bamboo fibre

2.**Preparation of cellulose from bamboo fibre and de-waxing of bamboo fibre**: The 400 mL toluene and 200 mL of ethyl alcohol are filled into a round flask to produce toluene-ethanol of ratio 2:1. The round flask is placed on a heating element. A Soxhlet extractor is placed on top of the boiling flask and fixed firmly using a retort stand. About 10 grams of GBF is scooped into a membrane tube and placed into the extraction thimble. A Liebig condenser is placed on top of the extractor and then fixed firmly. The temperature of the heating element is observed using a digital thermometer and it is maintained at 250°C. The extraction process is continued till the colour mixture disappears. The process takes 2 hours with approximately 10–12 cycles of extraction. The extraction thimble is taken out using tweezers. The product is transferred into a beaker and stirred using a glass rod while adding toluene-ethanol mixture. The final product is filtered using a filter paper placed on a funnel. It is then distributed evenly using glass rod on a filter paper. It is then placed in an oven set to temperature 70°C for drying overnight and is kept for delignification processes. The dried sample is identified as dewaxed bamboo fibre (DBF).

3.**Delignification of bamboo fibre:** The delignification solution is prepared using 82.3 g of 35% by weight of hydrogen peroxide (H2O2) and 106.2 g of 99.8% by weight of acetic acid (CH3COOH) in the present of titanium (IV) oxide as catalyst. Thirty grams of dry DBF sample is weighed and immersed into delignification solution contained in a round bottom flask. The flask is placed on the heating element and heated to 130°C. After 2 hours, the heater is switched off and cooled to room temperature. The treated product is then filtered using Buchner flask and rinsed with de-ionized (DI) water until the pH level reaches 7 and dried at 70°C for 1 day. The dried sample is placed in a bottle and kept in a cool and dark place for alkaline treatment. The sample so

4.**Mercerization:** DLBF is finally immersed in an alkaline solution in order to dissolve the pectin and hemicelluloses. 6% by weight of sodium hydroxide is used to treat the DLBF in a flask at room temperature. The mixture is stirred using auto shaker at 150 rpm, heated to 80°C for 2 hours, and stopped after 8 hours of proper stirring. The mixture is then rinsed continuously with de-ionized water until the product reaches pH 7. The treated product is finally filtered using Buchner flask, rinsed with de-ionized water until the pH level

After extraction of cellulose, it is generally characterized by using the following

obtained is delignified bamboo fibre (DLBF).

reaches 7, and freeze-dried at −85°C for 2 days [31].

*6.1.2.4 Characterization of cellulose extracted from bamboo*

**66**

techniques:


#### *6.1.2.5 Characterization of cellulose extracted from rice husk fibres*

The chemical conformation of rice husk at individual phase of action is originate to be giving to the approaches conveyed by the Technical Association of Pulp and Paper Industry (TAPPI). The cellulose and hemicellulose contents are retrieved conferring to TAPPI standard T203 OS-74 though the lignin content is restrained according to TAPPI normal T222 OS-83. The silica ash content is calculated by

#### **Figure 5.**

*Comparative differences of FTIR peaks into green bamboo fibre (GBF) and cellulose fibre (CF). The peak intensity at 1514 cm<sup>−</sup><sup>1</sup> from the spectrum of the GBF is credited to the C═C stretching vibration in the aromatic ring of lignin. Yet, the cellulose fibre did not show the C═C stretching at that region. This is an indication that the lignin was well removed by chemical process [30, 32].*

#### **Figure 6.**

*BJH surface area for four samples. It was noted that there was an increase in the BJH surface area of GBF and a decrease after DLBF. The decreased surface area of cellulose fibre might be a result of the mechanical grinding process that creates smaller cellulose fibre thus reduced the surface area. This result also indicates that mechanical grinding should be avoided to obtain higher BJH surface area. The final cellulose fibre showed that BJH surface area is two times greater than the initial green bamboo fibre [30, 32].*

#### **Figure 7.**

*The thermogravimetric analysis of (GBF, DBF, DLBF and CF) green bamboo fibre, dewaxed bamboo fibre, delignified bamboo fibre and cellulose fibre, respectively. The weight loss rate was obtained from the derivative thermogravimetric (DTG) data. The intersection of tangents drawn from thermogravimetric curve, one before inflection caused by the degradation and another from the cellulose degradation step indicates the onset degradation temperature [30].*

means of the thermogravimetric examination (TGA) data. The arrangement of silica ash was found at temperatures 900°C as the residual ash at this point can be credited to the silica ash [30, 33, 34].

#### *6.1.2.6 Scanning electron microscopy (SEM)*

It is utilized to detect the superficial morphology of the rice husk fibres. The effect of the numerous chemical treatments is evaluated using an assessment of the raw, alkali treated, and bleached fibres. Rice husk fibres is reserved on the aluminium stub and raised in the oven at 60°C. The samples are then covered with gold by means of a vacuum sputter coater (model SC 500). The width of the gold layer is approximately 0.01–0.1 μm. The fast-tracking voltage is 15 kV. Transmission electron microscopy (TEM) is used to regulate the proportions of the cellulose nanocrystals attained from the rice husk fibres. A drop of a diluted suspension (1% by weight) is placed on the superficial of a clean copper grid and covered through a thin carbon film. As for contrast in TEM, the cellulose nanocrystals are undesirably stained in a 2% by weight solution of uranyl acetate for 10 seconds then carried away by means of 50% by weight of sieved alcohol. Later sample is dehydrated at ambient temperature before TEM examination is approved out through an accelerating voltage of 80 kV (**Figure 8**).

**69**

400–4000 cm<sup>−</sup><sup>1</sup>

**Figure 8.**

data (**Figure 10**).

*An Update on Overview of Cellulose, Its Structure and Applications*

*6.1.2.7 Fourier transform infrared (FTIR) spectroscopy*

(**Figure 9**).

*methylimidazolium diethyl phosphate pretreatments [34].*

*6.1.2.9 Thermogravimetric analysis (TGA)*

*6.1.2.8 X-ray diffraction (XRD)*

Fourier transform infrared spectra are noted with the assistance of a Perkin-Elmer FTIR spectrophotometer. Un-treated, alkali-treated, blanched, and acidhydrolysed rice husk fibres models are examined. Models are excellently crushed and mixed with potassium bromide. The combination is then flattened to pellet form. FTIR spectral investigation is achieved inside the wave number range of

*SEM images of (a) untreated rice husk and rice husk residues of (b) [BMIM]Cl, 1-butyl-3-methylimidazolium* 

*chloride; (c) [EMIM] OAc, 1-ethyl-3-methylimidazolium acetate; and (d) [EMIM] DEP, 1-ethyl-3-*

X-ray diffraction is applied to identify the crystallinity of rice husk grits after numerous extraction methods. Each sample/material in the arrangement of milled powder is set aside on the sample vessel and levelled to attain complete and unvarying X-ray exposure. The trials are examined with the assistance of an X-ray diffractometer at room temperature (RT) by means of a monochromatic CuKα energy source (λ = 0.1539 nm) in the step-scan approach with a 2θ angle extending from 10 to 50°C with a stage of 0.04 and scanning period of 5 minutes. To characterize the crystallinity of the several samples, the crystallinity index CrI, is created based on the mirrored intensity

The thermal stability of the different samples is determined by TGA measurements performed using a Mettler Toledo thermogravimetric analyser. The quantity

*DOI: http://dx.doi.org/10.5772/intechopen.84727*

#### **Figure 8.**

*Cellulose*

**Figure 6.**

**Figure 7.**

**68**

means of the thermogravimetric examination (TGA) data. The arrangement of silica ash was found at temperatures 900°C as the residual ash at this point can be

*The thermogravimetric analysis of (GBF, DBF, DLBF and CF) green bamboo fibre, dewaxed bamboo fibre, delignified bamboo fibre and cellulose fibre, respectively. The weight loss rate was obtained from the derivative thermogravimetric (DTG) data. The intersection of tangents drawn from thermogravimetric curve, one before inflection caused by the degradation and another from the cellulose degradation step indicates the onset* 

*BJH surface area for four samples. It was noted that there was an increase in the BJH surface area of GBF and a decrease after DLBF. The decreased surface area of cellulose fibre might be a result of the mechanical grinding process that creates smaller cellulose fibre thus reduced the surface area. This result also indicates that mechanical grinding should be avoided to obtain higher BJH surface area. The final cellulose fibre showed that* 

*BJH surface area is two times greater than the initial green bamboo fibre [30, 32].*

It is utilized to detect the superficial morphology of the rice husk fibres. The effect of the numerous chemical treatments is evaluated using an assessment of the raw, alkali treated, and bleached fibres. Rice husk fibres is reserved on the aluminium stub and raised in the oven at 60°C. The samples are then covered with gold by means of a vacuum sputter coater (model SC 500). The width of the gold layer is approximately 0.01–0.1 μm. The fast-tracking voltage is 15 kV. Transmission electron microscopy (TEM) is used to regulate the proportions of the cellulose nanocrystals attained from the rice husk fibres. A drop of a diluted suspension (1% by weight) is placed on the superficial of a clean copper grid and covered through a thin carbon film. As for contrast in TEM, the cellulose nanocrystals are undesirably stained in a 2% by weight solution of uranyl acetate for 10 seconds then carried away by means of 50% by weight of sieved alcohol. Later sample is dehydrated at ambient temperature before TEM examination is approved out through an

credited to the silica ash [30, 33, 34].

*degradation temperature [30].*

*6.1.2.6 Scanning electron microscopy (SEM)*

accelerating voltage of 80 kV (**Figure 8**).

*SEM images of (a) untreated rice husk and rice husk residues of (b) [BMIM]Cl, 1-butyl-3-methylimidazolium chloride; (c) [EMIM] OAc, 1-ethyl-3-methylimidazolium acetate; and (d) [EMIM] DEP, 1-ethyl-3 methylimidazolium diethyl phosphate pretreatments [34].*

#### *6.1.2.7 Fourier transform infrared (FTIR) spectroscopy*

Fourier transform infrared spectra are noted with the assistance of a Perkin-Elmer FTIR spectrophotometer. Un-treated, alkali-treated, blanched, and acidhydrolysed rice husk fibres models are examined. Models are excellently crushed and mixed with potassium bromide. The combination is then flattened to pellet form. FTIR spectral investigation is achieved inside the wave number range of 400–4000 cm<sup>−</sup><sup>1</sup> (**Figure 9**).

#### *6.1.2.8 X-ray diffraction (XRD)*

X-ray diffraction is applied to identify the crystallinity of rice husk grits after numerous extraction methods. Each sample/material in the arrangement of milled powder is set aside on the sample vessel and levelled to attain complete and unvarying X-ray exposure. The trials are examined with the assistance of an X-ray diffractometer at room temperature (RT) by means of a monochromatic CuKα energy source (λ = 0.1539 nm) in the step-scan approach with a 2θ angle extending from 10 to 50°C with a stage of 0.04 and scanning period of 5 minutes. To characterize the crystallinity of the several samples, the crystallinity index CrI, is created based on the mirrored intensity data (**Figure 10**).

#### *6.1.2.9 Thermogravimetric analysis (TGA)*

The thermal stability of the different samples is determined by TGA measurements performed using a Mettler Toledo thermogravimetric analyser. The quantity

**Figure 9.**

*FTIR spectra for RH (rice husk), RH extractive-free, alkaline treated RH (RH after 15 minutes autoclave), RH cellulose (after 30 minutes bleaching) and commercial microcrystalline cellulose (MCC) in the range from 2000 to 800 cm<sup>−</sup><sup>1</sup> [34].*

#### **Figure 10.**

*X-ray diffractograms of rice husk (RH), bleached rice husk (RHB), rise husk nanofibrin after 1 and 2 hour of bleaching (RHNF1h and RHNF2h, respectively) [34].*

of sample involved for individual measurement remained approximately 1 mg. Each measurement is achieved under a nitrogen based generated atmosphere through a gas flow of 10 mL min<sup>−</sup><sup>1</sup> by means of heating the substantial from room temperature to 900°C at a heating rate of 10°C min<sup>−</sup><sup>1</sup> [34].

#### **7. Applications of cellulose**

Cellulose is the most richly found organic polymer, as it is a major structural component of the primary cell wall of green plants, several algae and oomycetes. Cellulose is found in large quantities in frequently used materials like cotton (90%),

**71**

*An Update on Overview of Cellulose, Its Structure and Applications*

Wood (50%) and dried Hemp (57%). It has numerous applications in various fields, but it is most frequently used in the manufacturing of paper and cardboard or in derivative products like cellophane and rayon. It is also a major component of textiles made from cotton or linen. Further, its use is seen in the pharmaceutical industry as inactive fillers in drugs, in the form of powdered cellulose and microcrystalline cellulose. However, one of the most important uses of cellulose is in the production of biofuel and in the food Industry. This will be elaborated further in

A drastic increase in the population of the world coupled with an exponential increase in technological advancements and need of the people, fossil fuels are being rapidly depleted. At such an hour, the term sustainable development comes into play. In order to develop sustainably, it is important to switch to a fuel that is more clean, green and more cost-effective. One such alternative, is cellulose derived biofuel. There are numerous advantages of using biofuel, the first and foremost being cost-effective. Recent studies have shown that due to increase in demand, the cost of biofuel is decreasing as ethanol costs lesser than petrol and diesel. Further, there is a significant reduction in the carbon emission. The raw material used for biofuel is simply a substrate that has cellulose in it. Since cellulose is so widely

The ethanol obtained from cellulose is used as an alternative substrate in the production of biofuel. It is considered a superior source due to its high energy efficiency and low cost as compared to other sources. This is a very good source for renewable energy as it is found most abundantly in stalks, leaves and stem of green plants. Other sources for ethanol include, feedstocks, including wheat straw, rice straw, sawdust, forest thinning and grasses perennial grasses and switchgrass. Cellulose can be broken down into fermentable sugars by using the fungus *Trichoderma reesei* or by using acid to convert them first into sugars and then into gas. The gut of termites also can be utilized for this purpose. Further, a group of bacteria collectively referred to as methanogens have the ability to digest cellulose and produce carbon di oxide and methane, which is further processed. One group of such bacteria called methanobacteria grow anaerobically on cellulosic matter and degrade it to produce methane. They are also found in the rumen of cattle and the dung of cattle. As is seen from this, it is quite easy to obtain a substrate for biogas production especially by using waste cellulosic material. Therefore, it is important that to utilize even the apparent waste material to ensure a reduction in wastage and

Cellulose has numerous applications in the field of pharmaceuticals and food technology. Modifying the structure of cellulose with other chemical groups results in the production of structures that have better bio-compatibility, flexibility, stability, emulsifying effects. Further, cellulose being indigestible by human beings, tend to have zero calorific value and can thus have been added in food to serve several purposes. Compounds like HPMC, sodium carboxymethyl cellulose, hydroxyethyl cellulose and others are commonly utilized in the pharmaceutical industry and food

technology industry. Some of these uses are enumerated below:

*DOI: http://dx.doi.org/10.5772/intechopen.84727*

**7.1 Use of cellulose in renewable energy**

abundant, the cost is significantly lower.

optimum usage of its potential [34, 35].

**7.2 Use of cellulose in consumables**

the following sections [33].

*7.1.1 Biofuel*

Wood (50%) and dried Hemp (57%). It has numerous applications in various fields, but it is most frequently used in the manufacturing of paper and cardboard or in derivative products like cellophane and rayon. It is also a major component of textiles made from cotton or linen. Further, its use is seen in the pharmaceutical industry as inactive fillers in drugs, in the form of powdered cellulose and microcrystalline cellulose. However, one of the most important uses of cellulose is in the production of biofuel and in the food Industry. This will be elaborated further in the following sections [33].

#### **7.1 Use of cellulose in renewable energy**

#### *7.1.1 Biofuel*

*Cellulose*

**70**

**Figure 10.**

**Figure 9.**

*to 800 cm<sup>−</sup><sup>1</sup>*

 *[34].*

*bleaching (RHNF1h and RHNF2h, respectively) [34].*

ture to 900°C at a heating rate of 10°C min<sup>−</sup><sup>1</sup>

gas flow of 10 mL min<sup>−</sup><sup>1</sup>

**7. Applications of cellulose**

*X-ray diffractograms of rice husk (RH), bleached rice husk (RHB), rise husk nanofibrin after 1 and 2 hour of* 

*FTIR spectra for RH (rice husk), RH extractive-free, alkaline treated RH (RH after 15 minutes autoclave), RH cellulose (after 30 minutes bleaching) and commercial microcrystalline cellulose (MCC) in the range from 2000* 

of sample involved for individual measurement remained approximately 1 mg. Each measurement is achieved under a nitrogen based generated atmosphere through a

Cellulose is the most richly found organic polymer, as it is a major structural component of the primary cell wall of green plants, several algae and oomycetes. Cellulose is found in large quantities in frequently used materials like cotton (90%),

by means of heating the substantial from room tempera-

[34].

A drastic increase in the population of the world coupled with an exponential increase in technological advancements and need of the people, fossil fuels are being rapidly depleted. At such an hour, the term sustainable development comes into play. In order to develop sustainably, it is important to switch to a fuel that is more clean, green and more cost-effective. One such alternative, is cellulose derived biofuel. There are numerous advantages of using biofuel, the first and foremost being cost-effective. Recent studies have shown that due to increase in demand, the cost of biofuel is decreasing as ethanol costs lesser than petrol and diesel. Further, there is a significant reduction in the carbon emission. The raw material used for biofuel is simply a substrate that has cellulose in it. Since cellulose is so widely abundant, the cost is significantly lower.

The ethanol obtained from cellulose is used as an alternative substrate in the production of biofuel. It is considered a superior source due to its high energy efficiency and low cost as compared to other sources. This is a very good source for renewable energy as it is found most abundantly in stalks, leaves and stem of green plants. Other sources for ethanol include, feedstocks, including wheat straw, rice straw, sawdust, forest thinning and grasses perennial grasses and switchgrass. Cellulose can be broken down into fermentable sugars by using the fungus *Trichoderma reesei* or by using acid to convert them first into sugars and then into gas. The gut of termites also can be utilized for this purpose. Further, a group of bacteria collectively referred to as methanogens have the ability to digest cellulose and produce carbon di oxide and methane, which is further processed. One group of such bacteria called methanobacteria grow anaerobically on cellulosic matter and degrade it to produce methane. They are also found in the rumen of cattle and the dung of cattle. As is seen from this, it is quite easy to obtain a substrate for biogas production especially by using waste cellulosic material. Therefore, it is important that to utilize even the apparent waste material to ensure a reduction in wastage and optimum usage of its potential [34, 35].

#### **7.2 Use of cellulose in consumables**

Cellulose has numerous applications in the field of pharmaceuticals and food technology. Modifying the structure of cellulose with other chemical groups results in the production of structures that have better bio-compatibility, flexibility, stability, emulsifying effects. Further, cellulose being indigestible by human beings, tend to have zero calorific value and can thus have been added in food to serve several purposes. Compounds like HPMC, sodium carboxymethyl cellulose, hydroxyethyl cellulose and others are commonly utilized in the pharmaceutical industry and food technology industry. Some of these uses are enumerated below:

#### *7.2.1 Hydroxypropyl methylcellulose*

HPMC is widely utilized in the pharmaceutical industry not only because it is safe and nontoxic but also because it does not get engrossed orally and does not upsurge the energy of foods. It is utilized as a film-forming agent, thickener, blocker, sustainedrelease agent, blending agent and suspending agent in many dosage forms, thus forming the numerous pharmaceutical preparation consistently discrete, tough short of being wrecked due to sustained release effects or steady emulsion without stratification. It is regularly used as a matrix, adhesives, frame ingredients, the film creating material or in the creation of sustained or controlled release microcapsules and pellets [36].

#### *7.2.2 Sodium carboxymethyl cellulose*

It used as an emulsion stabilizer in injections, adhesion and film-forming materials which have proved to be effective in controlling wound infections and can reduce postoperative oedema and wound stimulation phenomena. Animal experiments have shown that sodium carboxymethyl cellulose is a safe and reliable carrier of anticancer drugs [37].

#### *7.2.3 Hydroxyethyl cellulose*

In ice cream, frozen milk drinks, it is added as a stabilizer to extend the storage life and improve the overflow property. It is also used as the stabilizer of beer foam.

#### *7.2.4 Food*

Due to its unique physical and chemical properties and its behaviour in water, it is today being increasingly used a food additive to improve the bulk and fibre content of foods without having a major impact on the flavour of the food. Since it is indigestible by humans, it has no caloric value and is thus used in excessive amounts in diet foods to create a sensation of fullness both physical and physiology without having consumed too many calories. It is also widely used an emulsifier and a thickening agent in whipped cream, sauces and ice cream [38].

#### **7.3 Biomedical and pharmaceutical applications of cellulose**

Cellulose, with its properties, as discussed in previous sections of this manuscript, is extensively used in the field of biomedicine and pharmaceuticals. The cost of several pharmaceutical products is extremely high due to production factors such as high cost, difficulty in procuring the material, complicated processing steps etc. These problems can be remedied by the use of cellulose, which is found abundantly in nature. The most productive use of cellulose would be the utilization of plant based waste materials which are produced in bulk by many industries such as the sugar production industry as well as in minor quantities by households. The applications highlighted below could be brought to mainstream commercial use with the appropriate optimization techniques and novel modifications to the various steps of the production and processing of cellulosic material.

#### *7.3.1 Cellulose in coating of solid dosage forms and compressibility enhancers*

Solid dosage forms including pills, tablets, granules, pellets, microcapsules and spherules can be coated, usually with the aim to protect the drug from adverse environmental factors such as humidity, oxygen, enzymatic or acidic degradation.

**73**

*An Update on Overview of Cellulose, Its Structure and Applications*

Coating may also be used to facilitate drug delivery systems with altered release mechanisms such as delayed release, extended release, step-by-step release, pulsatile release and sustained release. Derivatives of cellulose such as esters and ethers are also extensively used as coating materials. In the process of solid dosage form manufacture by direct compression, a problem that frequently occurs is low compactability of the drug, this is more seen more frequently when the amount of drug in the formulation exceeds 30%. Many attempts are being made to reduce the price of the final product by experimenting with various starting materials and test conditions [39].

From the advent of novel drug delivery systems, cellulose based models seemed like strong candidates due to their projected benefits. Since then various advances have been made with the aim to bring its use to common practice. There are still many hurdles to cross before this becomes a reality. Cellulose based drug delivery is an important step in green and sustainable pharmacy which focuses on toxicity reduction, biodegradability and less hazardous synthesis with respect to drugs and drug delivery systems. A very brief overview of the primary ways in which it is used is provided here. Cellulose nanocrystals (CNCs) have the potential to acquire a negative charge during hydrolysis. This coupled with their large surface area allow them to bind ionizable drugs such as tetracycline and doxorubicin permitting optimum dosing control. Sites for surface modification for multiple chemicals are provided by the multitude of surface hydroxyl groups. This is used in case of non-ionized or hydrophobic drugs which do not generally bind to cellulose. The open pore structure and high surface area of CNC based aerogels provide increased drug loading capacity and drug bioavailability. Extremely porous aerogel scaffolds were reported to attain sustained drug release [40]. Cellulose derivatives have also been researched in terms of drug delivery. For instance, cellulose acetate has been successfully used in several HIV drugs, five flavonoids, one pain reliever and two antibiotics among others. Hydroxypropyl

methylcellulose has been used in oral drug delivery formulations [41].

This property was reported to be enhanced by periodate oxidation [42].

BNC is specifically nondegradable under physiological conditions and has been shown to be biocompatible. These properties further impart durable mechanical properties and long-term chemical stability which make it an exciting candidate for

Scaffolds are materials that have been engineered to cause desirable cellular interactions to contribute to the formation of new functional tissues for medical purposes by providing the microenvironment required by cells to proliferate, migrate and differentiate. It contributes the geometrical basis and building blocks to provide cell attachment. *Gluconacetobacter xylinus* sourced nanocellulose is an emerging biomaterial for this purpose. Bacterial nanocellulose has a very high affinity for water and therefore displays properties similar to those of hydrogels which provides an ideal environment to host cells. Studies have confirmed that human smooth muscle cells, bone forming osteoblasts and fibroblasts and human embryonic kidney cells can grow in the presence of bacterial cellulose scaffolds. The main challenge in the production of these scaffolds seems to be biodegradability as the cellulose, the enzyme required to breakdown cellulose is not present in humans.

*DOI: http://dx.doi.org/10.5772/intechopen.84727*

*7.3.2 Cellulose in drug delivery*

*7.3.3 Cellulose in scaffolding*

*7.3.4 Cellulose in biomedical implants*

application in this field:

#### *An Update on Overview of Cellulose, Its Structure and Applications DOI: http://dx.doi.org/10.5772/intechopen.84727*

Coating may also be used to facilitate drug delivery systems with altered release mechanisms such as delayed release, extended release, step-by-step release, pulsatile release and sustained release. Derivatives of cellulose such as esters and ethers are also extensively used as coating materials. In the process of solid dosage form manufacture by direct compression, a problem that frequently occurs is low compactability of the drug, this is more seen more frequently when the amount of drug in the formulation exceeds 30%. Many attempts are being made to reduce the price of the final product by experimenting with various starting materials and test conditions [39].

#### *7.3.2 Cellulose in drug delivery*

*Cellulose*

*7.2.1 Hydroxypropyl methylcellulose*

*7.2.2 Sodium carboxymethyl cellulose*

of anticancer drugs [37].

*7.2.3 Hydroxyethyl cellulose*

*7.2.4 Food*

HPMC is widely utilized in the pharmaceutical industry not only because it is safe and nontoxic but also because it does not get engrossed orally and does not upsurge the energy of foods. It is utilized as a film-forming agent, thickener, blocker, sustainedrelease agent, blending agent and suspending agent in many dosage forms, thus

forming the numerous pharmaceutical preparation consistently discrete, tough short of being wrecked due to sustained release effects or steady emulsion without stratification. It is regularly used as a matrix, adhesives, frame ingredients, the film creating material or in the creation of sustained or controlled release microcapsules and pellets [36].

It used as an emulsion stabilizer in injections, adhesion and film-forming materials which have proved to be effective in controlling wound infections and can reduce postoperative oedema and wound stimulation phenomena. Animal experiments have shown that sodium carboxymethyl cellulose is a safe and reliable carrier

In ice cream, frozen milk drinks, it is added as a stabilizer to extend the storage life and improve the overflow property. It is also used as the stabilizer of beer foam.

Due to its unique physical and chemical properties and its behaviour in water, it is today being increasingly used a food additive to improve the bulk and fibre content of foods without having a major impact on the flavour of the food. Since it is indigestible by humans, it has no caloric value and is thus used in excessive amounts in diet foods to create a sensation of fullness both physical and physiology without having consumed too many calories. It is also widely used an emulsifier and

Cellulose, with its properties, as discussed in previous sections of this manuscript, is extensively used in the field of biomedicine and pharmaceuticals. The cost of several pharmaceutical products is extremely high due to production factors such as high cost, difficulty in procuring the material, complicated processing steps etc. These problems can be remedied by the use of cellulose, which is found abundantly in nature. The most productive use of cellulose would be the utilization of plant based waste materials which are produced in bulk by many industries such as the sugar production industry as well as in minor quantities by households. The applications highlighted below could be brought to mainstream commercial use with the appropriate optimization techniques and novel modifications to the various steps of

a thickening agent in whipped cream, sauces and ice cream [38].

**7.3 Biomedical and pharmaceutical applications of cellulose**

the production and processing of cellulosic material.

*7.3.1 Cellulose in coating of solid dosage forms and compressibility enhancers*

spherules can be coated, usually with the aim to protect the drug from adverse environmental factors such as humidity, oxygen, enzymatic or acidic degradation.

Solid dosage forms including pills, tablets, granules, pellets, microcapsules and

**72**

From the advent of novel drug delivery systems, cellulose based models seemed like strong candidates due to their projected benefits. Since then various advances have been made with the aim to bring its use to common practice. There are still many hurdles to cross before this becomes a reality. Cellulose based drug delivery is an important step in green and sustainable pharmacy which focuses on toxicity reduction, biodegradability and less hazardous synthesis with respect to drugs and drug delivery systems. A very brief overview of the primary ways in which it is used is provided here. Cellulose nanocrystals (CNCs) have the potential to acquire a negative charge during hydrolysis. This coupled with their large surface area allow them to bind ionizable drugs such as tetracycline and doxorubicin permitting optimum dosing control. Sites for surface modification for multiple chemicals are provided by the multitude of surface hydroxyl groups. This is used in case of non-ionized or hydrophobic drugs which do not generally bind to cellulose. The open pore structure and high surface area of CNC based aerogels provide increased drug loading capacity and drug bioavailability. Extremely porous aerogel scaffolds were reported to attain sustained drug release [40].

Cellulose derivatives have also been researched in terms of drug delivery. For instance, cellulose acetate has been successfully used in several HIV drugs, five flavonoids, one pain reliever and two antibiotics among others. Hydroxypropyl methylcellulose has been used in oral drug delivery formulations [41].

#### *7.3.3 Cellulose in scaffolding*

Scaffolds are materials that have been engineered to cause desirable cellular interactions to contribute to the formation of new functional tissues for medical purposes by providing the microenvironment required by cells to proliferate, migrate and differentiate. It contributes the geometrical basis and building blocks to provide cell attachment. *Gluconacetobacter xylinus* sourced nanocellulose is an emerging biomaterial for this purpose. Bacterial nanocellulose has a very high affinity for water and therefore displays properties similar to those of hydrogels which provides an ideal environment to host cells. Studies have confirmed that human smooth muscle cells, bone forming osteoblasts and fibroblasts and human embryonic kidney cells can grow in the presence of bacterial cellulose scaffolds. The main challenge in the production of these scaffolds seems to be biodegradability as the cellulose, the enzyme required to breakdown cellulose is not present in humans. This property was reported to be enhanced by periodate oxidation [42].

#### *7.3.4 Cellulose in biomedical implants*

BNC is specifically nondegradable under physiological conditions and has been shown to be biocompatible. These properties further impart durable mechanical properties and long-term chemical stability which make it an exciting candidate for application in this field:


#### **8. Conclusion**

From the chapter we can conclude that cellulose is a highly versatile polymer which is easy to manufacture and extract. Its application in multiple fields has been discussed above. With increasing population, demand and technological innovations, renewable energy is gradually becoming imperative aspect of resource conservation and overall environmental health. Although various other polymers can be utilized for consumables, biomedical and pharmaceutical applications, the marked advantage of cellulose is that it is a biodegradable and environmentally friendly material. The intensive research on the chemistry of the compound, has resulted in the production of a wide variety of biodegradable products with a plethora of applications. An improved information of the many structural levels in which cellulose partakes will allow us to understand better practise of this exceptional and metastable molecular assembly produced by plant metabolic pathways. We have placed emphasis on the diverse applications of cellulose to promote more innovations that aim to bridge the gap between the amounts of cellulosic waste and its optimum utilization. Large amounts of cellulose based wastes are produced in every community across the world, which remain a largely untapped resource. Research that involves the conversion of this perceived waste into a widely used commodity would have the dual benefit of organic waste management and sustainable innovations.

#### **Acknowledgements**

The authors listed in this chapter wish to express their appreciation to the RSST trust Bangalore for their continuation support and encouragement. As a corresponding author, I also express my sincere thanks to all other authors whose valuable contribution and important comments make this manuscript in this form.

#### **Conflict of interest**

The authors listed in this chapter have no conflict of interest known best from our side. There was also no problem related to funding. All authors have contributed equally with their valuable comments which made the manuscript to this form.

**75**

*An Update on Overview of Cellulose, Its Structure and Applications*

There was no funding provided for the above research and preparation of the

*DOI: http://dx.doi.org/10.5772/intechopen.84727*

DP degree of polymerization NMR nuclear magnetic resonance

HPC hydroxypropyl cellulose MCC microcrystalline cellulose TGA thermogravimetric analysis

FTIR Fourier transform infrared spectroscopy

DSC differential scanning calorimetry SEM scanning electron microscopy

AmimCl 1-allyl-3-methylimidazolium chloride

BJH Barrett-Joyner-Halenda analysis DTG derivative thermogravimetric

HIV human immunodeficiency virus

GTR guided tissue regeneration

HS Hestrin-Schramm CMC carboxymethyl cellulose PKC palm kernel cake EC ethylcellulose

XRD X-ray diffraction

SCB sugarcane bagasse GBF green bamboo fibre DBF dewaxed bamboo fibre

DLBF delignified bamboo fibre

CNC cellulose nanocrystal

ER extended release BNC bacterial nanocellulose BC bacterial cellulose HAp hydroxyapatite

DI deionized

IL ionic liquid DMSO dimethyl sulfoxide

**Funding information**

**List of abbreviations**

manuscript.

*An Update on Overview of Cellulose, Its Structure and Applications DOI: http://dx.doi.org/10.5772/intechopen.84727*

### **Funding information**

*Cellulose*

• Cardiovascular implants: Bacterial cellulose has an important application in artificial blood vessels. Compared to the material generally used for vascular grafts, these materials show less thrombosis and occlusion. Heparin hybridized bacterial nanocellulose scaffolds with anticoagulant properties have potential use in vascular tissue engineering. Potential use of BC in the production of

• Bone and connective tissue repair: Nanocellulose are promising materials for the culture of various cells including osteoblasts and chondroblasts indicating that they have potential for bone tissue regeneration and healing. A membrane of BC and hydroxyapatite was developed as biomaterial for potential bone regeneration, which delivered prone growth of osteoblast cells, high level of alkaline phosphatase activity and greater bone nodule formation. It was also found that HAp crystals are partially substituted with carbonate resembling

From the chapter we can conclude that cellulose is a highly versatile polymer which is easy to manufacture and extract. Its application in multiple fields has been discussed above. With increasing population, demand and technological innovations, renewable energy is gradually becoming imperative aspect of resource conservation and overall environmental health. Although various other polymers can be utilized for consumables, biomedical and pharmaceutical applications, the marked advantage of cellulose is that it is a biodegradable and environmentally friendly material. The intensive research on the chemistry of the compound, has resulted in the production of a wide variety of biodegradable products with a plethora of applications. An improved information of the many structural levels in which cellulose partakes will allow us to understand better practise of this exceptional and metastable molecular assembly produced by plant metabolic pathways. We have placed emphasis on the diverse applications of cellulose to promote more innovations that aim to bridge the gap between the amounts of cellulosic waste and its optimum utilization. Large amounts of cellulose based wastes are produced in every community across the world, which remain a largely untapped resource. Research that involves the conversion of this perceived waste into a widely used commodity would have the dual benefit of organic waste management and sustain-

The authors listed in this chapter wish to express their appreciation to the RSST trust Bangalore for their continuation support and encouragement. As a corresponding author, I also express my sincere thanks to all other authors whose valuable contribution and important comments make this manuscript in this form.

The authors listed in this chapter have no conflict of interest known best from our side. There was also no problem related to funding. All authors have contributed equally with their valuable comments which made the manuscript to this form.

heart valve replacements has been explored [43, 44].

natural bones [45–47].

**8. Conclusion**

able innovations.

**Acknowledgements**

**Conflict of interest**

**74**

There was no funding provided for the above research and preparation of the manuscript.

### **List of abbreviations**


*Cellulose*

### **Author details**

Praveen Kumar Gupta\*, Shreeya Sai Raghunath, Deepali Venkatesh Prasanna, Priyadharsini Venkat, Vidhya Shree, Chandrananthi Chithananthan, Shreya Choudhary, Krithika Surender and Keerthana Geetha Department of Biotechnology, R.V College of Engineering, Bangalore, India

\*Address all correspondence to: praveenkgupta@rvce.edu.in

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**77**

*An Update on Overview of Cellulose, Its Structure and Applications*

Studies on Glycobiology and

digestion-in-ruminants

Nutrients. 2018;**10**(8):1055

2013;**195**(24):5540-5554

Glycotechnology. IntechOpen. 2012. DOI: 10.5772/51574. Available from: https://www.intechopen.com/books/ carbohydrates-comprehensive-studieson-glycobiology-and-glycotechnology/

[9] Zhang T, Yang Y, Liang Y, Jiao X, Zhao C. Beneficial effect of intestinal fermentation of natural polysaccharides.

[10] Serra D, Richter A, Hengge R. Cellulose as an architectural element in spatially structured *Escherichia coli* biofilms. Journal of Bacteriology.

[11] Fernandes A, Thomas L, Altaner C, Callow P, Forsyth V, Apperley D, et al. Nanostructure of cellulose microfibrils

in spruce wood. Proceedings of the National Academy of Sciences.

[12] Chawla S, Kanatt S, Sharma A. Chitosan. In: Ramawat K, Mérillon JM, ediors. Polysaccharides. Springer, Cham. 2015. pp. 219-246. https://doi. org/10.1007/978-3-319-16298-0\_13

[13] Li S, Bashline L, Lei L, Gu Y. Cellulose synthesis and its regulation. In: The Arabidopsis Book. Vol. 12. BiOne Complete(Open Access). 2014. p. e0169.

https://doi.org/10.1199/tab.0169

[14] Nobles DR, Romanovicz DK, Malcolm Brown R Jr. Cellulose in cyanobacteria. Origin of vascular plant cellulose synthase. Plant Physiology.

[15] Nakatsubo F, Kamitakahara H, Hori M. Cationic ring-opening polymerization of 3,6-di-O-benzyl-αd-glucose 1,2,4-Orthopivalate and the first chemical synthesis of cellulose. Journal of the American Chemical Society. 1996;**118**(7):1677-1681

2001;**127**:529-542

2011;**108**(47):E1195-E1203

*DOI: http://dx.doi.org/10.5772/intechopen.84727*

Hierarchical Organisation in the Most Abundant Biopolymer –Cellulose. MRS Proceedings. 2013. p. 1504, Mrsf12-1504-v02-03. DOI: 10.1557/

[1] Khandelwal M, Windle A.

[2] Holtzapple MT. Cellulose. In: Caballero B, editor. Encyclopedia of Food Sciences and Nutrition . 2nd ed. Academic Press. 2003:998-1007. ISBN 9780122270550. https://doi.org/10.1016/

[3] Aravamudhan A, Ramos DM, Nada A, Kumbar S. Natural Polymers: Polysaccharides and Their Derivatives

[4] Zhang Z, Ortiz O, Goyal R, Kohn J. Biodegradable Polymers. In: Principles of Tissue Engineering: 4th ed. Elsevier Inc. 2013:441-473. https://doi.org/10.1016/

[5] Rose M, Palkovits R. Cellulose-based sustainable polymers: State of the art and future trends. Macromolecular

[6] Kalia S, Dufresne A, Cherian B, Kaith B, Avérous L, Njuguna J, et al. Cellulose-

based bio- and nanocomposites: A Review. International Journal of Polymer Science. Vol. 2011, Article ID 837875, 35 pages, 2011. https://doi.

[7] Aunina Z, Bazbauers G, Valters K Feasibility of bioethanol production from Lignocellulosic biomass. Scientific Journal of Riga Technical University Environmental and Climate

[8] Niwińska B. Digestion in ruminants. In: Carbohydrates-Comprehensive

Technologies. 2010;**4**(-1):11-15

for Biomedical Applications. Natural and Synthetic Biomedical Polymers. 2014:67-89. DOI: 10.1016/ B978-0-12-396983-5.00004-1

B978-0-12-398358-9.00023-9

Rapid Communications. 2011;**32**(17):1299-1311

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**Author details**

provided the original work is properly cited.

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Praveen Kumar Gupta\*, Shreeya Sai Raghunath, Deepali Venkatesh Prasanna,

Department of Biotechnology, R.V College of Engineering, Bangalore, India

Priyadharsini Venkat, Vidhya Shree, Chandrananthi Chithananthan,

Shreya Choudhary, Krithika Surender and Keerthana Geetha

\*Address all correspondence to: praveenkgupta@rvce.edu.in

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[21] Fischer S, Thümmler K, Volkert B, Hettrich K, Schmidt I, Fischer K. Properties and applications of cellulose acetate. Macromolecular Symposia. 2008;**262**(1):89-96

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[23] Luchs J, Nelinson D, Macy J. Efficacy of Hydroxypropyl cellulose ophthalmic inserts (LACRISERT) in subsets of patients with dry eye syndrome: Findings from a patient registry. Cornea. 2010;**29**(12):1417-1427

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spherical orbital implants. Ophthalmic Plastic & Reconstructive Surgery.

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*Cellulose*

2001;**26**:1341-1417

[16] Zugenmaier P. Conformation and packing of various crystalline cellulose fibers. Progress in Polymer Science.

clinical outcomes: Tools for predicting response. Current Eye Research.

[25] Sanford-Smith J. Glaucoma. In: Eye Diseases in Hot Climates. 4th ed. India:

[26] Blumenthal H. The Appliance of Science (Melting Point). International Edition: The Guardian. 2004. Available from: https://www.theguardian. com/lifeandstyle/2004/nov/20/ foodanddrink.shopping3

[27] Matrosovich M, Matrosovich T, Garten W, Klenk HD. New low-viscosity overlay medium for viral plaque assays.

Virology Journal. 2006;**3**(1):63

[28] Lynch M, inventor; Lynch

US 10/752,173. 12 August 2004

[29] Saelee K, Yingkamhaeng N, Nimchua T, Sukyai P. Extraction and characterization of cellulose from sugarcane bagasse by using environmental friendly method. The 26th Annual Meeting of the Thai Society for Biotechnology and International

[30] Liew FK, Hamdan S, Rezaur M, Rahman MR, Lai JCH, Hossen MF, et al. Synthesis and characterization of cellulose from green bamboo by chemical treatment with mechanical process. Journal of Chemistry.

2015;**2015**:212158. 6 pages. http://dx.doi.

[31] Johar N, Ahmad I, Dufresne A. Extraction, preparation and

characterization of cellulose fibers and nanocrystals from rice husk. Industrial Crops and Products. 2012;**37**(1): 93-99. https://doi.org/10.1016/j.

Conference, TSB. 2014

org/10.1155/2015/212158

indcrop.2011.12.016

Maurice Gerard, assignee. Decorative skin and hair cosmetics containing microcrystalline cellulose as enhancing agent. United States patent application

2010;**35**(10):880-887

Elsevier; 2003. pp. 298-315

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[18] Klemm D, Fink BHH-P, Bohn A. Cellulose: Fascinating biopolymer and sustainable raw material Angew. Angewandte Chemie International

Edition. 2005;**44**:3358-3393

[19] Costa A, Almeida F, Vinhas G, Sarubbo L. Production of bacterial cellulose by *Gluconacetobacter hansenii* using corn steep liquor as nutrient sources. Frontiers in Microbiology. 2017;**8**

[20] Esa F, Tasirin S, Rahman N. Overview of bacterial cellulose

2014;**2**:113-119

2008;**262**(1):89-96

production and application. Agriculture and Agricultural Science Procedia.

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[22] Murtaza G. Ethylcellulose

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(LACRISERT) in subsets of patients with dry eye syndrome: Findings from a patient registry. Cornea.

[24] McDonald M, D'Aversa G, Perry HD, Wittpenn JR, Nelinson DS. Correlating patient-reported response to hydroxypropyl cellulose ophthalmic insert (LACRISERT®) therapy with

Sciences. 2012;**69**(1):11-22

2010;**29**(12):1417-1427

microparticles: A review. International Jornal of Pharmacy and Pharmaceutical

**78**

[33] Ang TN, Ngoh G, Chua A, Gyu Lee M. Elucidation of the effect of ionic liquid pretreatment on rice husk via structural analyses. Biotechnology for Biofuels. 2012;**5**:67. DOI: 10.1186/1754-6834-5-67

[34] Rosa SML, Rehman N, de Miranda MIG, Nachtigall SMB, Bica CID. Chlorine-free extraction of cellulose from rice husk and whisker isolation. Carbohydrate Polymers. 2012;**87**(2):1131-1138. ISSN 0144-8617. DOI: 10.1016/j.carbpol.2011.08.084

[35] Mettler M, Paulsen A, Vlachos D, Dauenhauer P. Pyrolytic conversion of cellulose to fuels: Levoglucosan deoxygenation via elimination and cyclization within molten biomass. Energy & Environmental Science. 2012;**5**(7):7864

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Section 3

Applications
