**3. Nanoparticle applications**

Nanomaterials have gained much attention due to their unique properties. Many engineered nanoparticles, such as nano silver (nano-Ag), nano TiO2 (nano-TiO2), nano aluminum oxide (nano-Al2O3) and carbon nanotubes (CNT), have found potential commercial applications in catalysis, biomedical researches, medicinal applications, etc. Their subsequent impending effects on the ecosystem have also raised concerns over human health and environments as evidence has suggested that engineered nanomaterials are likely to present potential risks. Numerous

active research and studies are carried out to analyze the health and environmental risk assessments. Although none of the analytical techniques employed provide unequivocal evidence as to the nature and impacts of the nanoparticles, advances in the analytical tools and techniques allowed to significantly enhance our understanding on the properties and roles of nanoparticles. One of the recent emerging fields for nanoparticle applications is agriculture and construction. In this review, examples of nanoparticle usages in these two fields of practices to date and the challenges associated with nanoparticle applications are introduced.

#### **3.1 Nanoparticle and bioichar**

Biochar (BC) is a carbon-rich product generated by pyrolysis of biomass such as wood, crop residues, and manure in a closed container with little or no oxygen. Creating biochar is a carbon-negative process because synthesizing BC utilizes naturally decaying organic matters to turn into useable sustainable materials while bypassing the release of CO2 into the atmosphere. Studies have shown that BC can substantially enhance physicochemical and biological properties of the soil to increase the plant and crop yields [98–101]. A number of remediation strategies using BC as sorbents are developed to remove toxic contaminants from polluted soils because of the high surface areas and presence of various carbon functional groups in BC. Furthermore, chemical structure of BC is stable and highly resistant to microbial degradation due to the recalcitrant nature of BC hence allowing BC to be an alternative growing medium or substrates for agronomic applications. For example, in 2010, the American Society of Agronomy Soil Science Society of the American Environmental Quality Division identified the agronomic applications of BC to be one of the immediate challenges and solutions to address the global food shortage. Clearly, more research on BC and its application to agronomic industry is urgently necessary for globally sustainable agricultural practices.

Recent report by Saxina et al. [102] provided evidence of biochar contains carbon nanoparticles. Presence of these carbon nanoparticles in the biochar significantly enhanced the soil fertility and nutrient retention compared to the ones without the carbon nanoparticles. Others also reported the properties of biochar containing the NPs differ from the properties of their macro-counterparts [103]. Different zeta potential, cation exchange capacity, elemental compositions, and aromaticity/polarity not only based on the type of biochars, but also the regularities in the differences between their macro- and nano-structure were observed suggesting the nanoparticles have substantial impacts on governing the overall properties of the biochar. They accounted that the larger surface area and smaller pore sizes than the corresponding macro-biochars are the main physicochemical properties. On the contrary, Chen et al. [104] reported nanoscale biochar particles may carry the inherent contaminants along the soil profile, posing a potential risk to the groundwater. Their study on the transport and retention of wood chip-derived biochar nanoparticles (NPs) in water-saturated columns packed with a paddy soil identified mobility of biochar NPs in natural soils must be taken into consideration for accurately assessing their environmental impacts. **Figure 6** illustrates the effects of different type of nanoparticle modifications on biochars to enhance the contaminant removal and transformation reactions of a wide range of environmental and anthropogenically abundant toxic matters.

In addition to the laboratory studies on biochar nanoparticles, field-scale experiments were carried and provided promising evidence on the impacts of the biochar nanoparticles to increase food production and remediation. Su et al. [105] synthesized biochar-supported zero-valent iron nanoparticles and used in the remediation of Cr(VI)-contaminated soil. They found removal of Cr(VI) was significantly

**345**

nutrients occur.

**Figure 6.**

**3.2 Nanoparticle and cement**

*Novel Applications of Nanoparticles in Nature and Building Materials*

improved and observed substantially increased cabbage mustard growth as the phytotoxicity of Cr(VI) and Fe in the seedlings was effectively decreased by the biochar nanoparticle treatment in the field. Yue et al. [106] also demonstrated that application of the biochar nanoparticles on the rice plants significantly alleviated the phytotoxicity of Cd2+. However, their study reported that the nano-biochar significantly increased the contents of antioxidative enzyme activities indicating that nano-biochar could also induce oxidative stress in the rice plants. These results indicate that nano-biochar could greatly reduce the uptake and phytotoxicity of Cd2+, but its potential risk should not be overlooked during the environmental and agricultural applications of biochar. Clearly more studies are needed before fully applying nanoparticles in biochar synthesis or application to the fields especially focusing on the the interaction between biochar nanoparticles and plant roots in the rhizosphere where most of the physico-chemical reactions between the plants and

*Schematic representation of biochar modifications by different types of nanoparticles and the subsequent* 

*enhanced reaction mechanisms in transformation of the contaminants in the environment.*

Portland cement based materials like concrete, mortar, fiber reinforcement and others are widely used building materials. About 4.1 billion metric tons of cement were produced in 2020 worldwide and a continuously increased demand is expected, elevating the environmental impacts related with this worldwide industry. Efforts have been made to mitigate the environmental impacts of cement production by creating different synthesis approaches and alternative methods for production. For example, geopolymeric cements are developed and commercially produced to reduce the carbon footprint of cement production, while also being highly durable and comparable to the traditional cements [107–110]. Recently, nano-engineered cement based materials is also actively studied because materials, such as nano-SiO2, nano-TiO2, nano-Fe2O3, nano-Al2O3, nano-CaCO3, nano-ZnO2, nano-cement particles of C2S and C3S phases, nano-clays, and Carbon Nanotubes, can work as effective binder to improve the cement based materials performance [111]. The addition of nanoparticles in cementitious materials can act as a filler agent, producing a dense matrix and reduce the growth of micro pores. Some nanoparticles also help in the secondary reactions forming cement composite and contribute to the strength development. Moreover, with the advancement on the analytical tools, the current knowledge of the microstructure, mechanical strength and durability of cementitious materials when incorporating different types of

nanoparticles increased during the past decades [112–114].

*DOI: http://dx.doi.org/10.5772/intechopen.97668*

*Novel Applications of Nanoparticles in Nature and Building Materials DOI: http://dx.doi.org/10.5772/intechopen.97668*

**Figure 6.**

*Novel Nanomaterials*

**3.1 Nanoparticle and bioichar**

active research and studies are carried out to analyze the health and environmental risk assessments. Although none of the analytical techniques employed provide unequivocal evidence as to the nature and impacts of the nanoparticles, advances in the analytical tools and techniques allowed to significantly enhance our understanding on the properties and roles of nanoparticles. One of the recent emerging fields for nanoparticle applications is agriculture and construction. In this review, examples of nanoparticle usages in these two fields of practices to date and the chal-

Biochar (BC) is a carbon-rich product generated by pyrolysis of biomass such as wood, crop residues, and manure in a closed container with little or no oxygen. Creating biochar is a carbon-negative process because synthesizing BC utilizes naturally decaying organic matters to turn into useable sustainable materials while bypassing the release of CO2 into the atmosphere. Studies have shown that BC can substantially enhance physicochemical and biological properties of the soil to increase the plant and crop yields [98–101]. A number of remediation strategies using BC as sorbents are developed to remove toxic contaminants from polluted soils because of the high surface areas and presence of various carbon functional groups in BC. Furthermore, chemical structure of BC is stable and highly resistant to microbial degradation due to the recalcitrant nature of BC hence allowing BC to be an alternative growing medium or substrates for agronomic applications. For example, in 2010, the American Society of Agronomy Soil Science Society of the American Environmental Quality Division identified the agronomic applications of BC to be one of the immediate challenges and solutions to address the global food shortage. Clearly, more research on BC and its application to agronomic industry is

lenges associated with nanoparticle applications are introduced.

urgently necessary for globally sustainable agricultural practices.

anthropogenically abundant toxic matters.

Recent report by Saxina et al. [102] provided evidence of biochar contains carbon nanoparticles. Presence of these carbon nanoparticles in the biochar significantly enhanced the soil fertility and nutrient retention compared to the ones without the carbon nanoparticles. Others also reported the properties of biochar containing the NPs differ from the properties of their macro-counterparts [103]. Different zeta potential, cation exchange capacity, elemental compositions, and aromaticity/polarity not only based on the type of biochars, but also the regularities in the differences between their macro- and nano-structure were observed suggesting the nanoparticles have substantial impacts on governing the overall properties of the biochar. They accounted that the larger surface area and smaller pore sizes than the corresponding macro-biochars are the main physicochemical properties. On the contrary, Chen et al. [104] reported nanoscale biochar particles may carry the inherent contaminants along the soil profile, posing a potential risk to the groundwater. Their study on the transport and retention of wood chip-derived biochar nanoparticles (NPs) in water-saturated columns packed with a paddy soil identified mobility of biochar NPs in natural soils must be taken into consideration for accurately assessing their environmental impacts. **Figure 6** illustrates the effects of different type of nanoparticle modifications on biochars to enhance the contaminant removal and transformation reactions of a wide range of environmental and

In addition to the laboratory studies on biochar nanoparticles, field-scale experiments were carried and provided promising evidence on the impacts of the biochar nanoparticles to increase food production and remediation. Su et al. [105] synthesized biochar-supported zero-valent iron nanoparticles and used in the remediation of Cr(VI)-contaminated soil. They found removal of Cr(VI) was significantly

**344**

*Schematic representation of biochar modifications by different types of nanoparticles and the subsequent enhanced reaction mechanisms in transformation of the contaminants in the environment.*

improved and observed substantially increased cabbage mustard growth as the phytotoxicity of Cr(VI) and Fe in the seedlings was effectively decreased by the biochar nanoparticle treatment in the field. Yue et al. [106] also demonstrated that application of the biochar nanoparticles on the rice plants significantly alleviated the phytotoxicity of Cd2+. However, their study reported that the nano-biochar significantly increased the contents of antioxidative enzyme activities indicating that nano-biochar could also induce oxidative stress in the rice plants. These results indicate that nano-biochar could greatly reduce the uptake and phytotoxicity of Cd2+, but its potential risk should not be overlooked during the environmental and agricultural applications of biochar. Clearly more studies are needed before fully applying nanoparticles in biochar synthesis or application to the fields especially focusing on the the interaction between biochar nanoparticles and plant roots in the rhizosphere where most of the physico-chemical reactions between the plants and nutrients occur.

## **3.2 Nanoparticle and cement**

Portland cement based materials like concrete, mortar, fiber reinforcement and others are widely used building materials. About 4.1 billion metric tons of cement were produced in 2020 worldwide and a continuously increased demand is expected, elevating the environmental impacts related with this worldwide industry. Efforts have been made to mitigate the environmental impacts of cement production by creating different synthesis approaches and alternative methods for production. For example, geopolymeric cements are developed and commercially produced to reduce the carbon footprint of cement production, while also being highly durable and comparable to the traditional cements [107–110]. Recently, nano-engineered cement based materials is also actively studied because materials, such as nano-SiO2, nano-TiO2, nano-Fe2O3, nano-Al2O3, nano-CaCO3, nano-ZnO2, nano-cement particles of C2S and C3S phases, nano-clays, and Carbon Nanotubes, can work as effective binder to improve the cement based materials performance [111]. The addition of nanoparticles in cementitious materials can act as a filler agent, producing a dense matrix and reduce the growth of micro pores. Some nanoparticles also help in the secondary reactions forming cement composite and contribute to the strength development. Moreover, with the advancement on the analytical tools, the current knowledge of the microstructure, mechanical strength and durability of cementitious materials when incorporating different types of nanoparticles increased during the past decades [112–114].

For example, Said et al. [115] demonstrate a wide range of nanoparticles like Al2O3, C–S–H-phase, and quartz have the best potential as accelerators for cement hydration and therefore are most suitable for cement production based on their result of heat flow calorimetry measurements, particles size of nanomaterials and their percentage in the cement paste. Gaitero et al. [116] also identified that the addition of small amounts of silica nanoparticles to the cement paste could substantially slow down a degradation process due to the progressive dissolution of the cement paste. Nazari and the co-workers [111] also identified nano-phase Al2O3 particles with the average diameter of 15 nm increased flexural strength of fresh concrete and the extent of this positive effects of nanoparticles amplified as the content of Al2O3 nanoparticles increased. It is concluded that partial replacement of cement with nanophase Al2O3 particles improves the split tensile and flexural strength of concrete but decreases its setting time. Kawashima et al. [112] combined two nanomaterials, namely calcium carbonate nanoparticles and nanosilica, to synthesize cementatious materials and observed the mixture can offset the negative effects of fly ash (i.e., precursor for cements) on early-age properties to facilitate the development of a more environmentally friendly, high-volume fly ash concrete. Lastly, Land and his co-workers [113] also investigated the effects of colloidal nanosilica on concrete incorporating cement binders and found that the concentrations of nano-silica determined the micro-structural and thermal property changes. Many studies to date suggest that utilizing nanoparticles in cement synthesis can benefit the system by improving many of the structural properties. Further indepth study on the mechanisms underlying the influence of nanoparticles on the compressive strength gain and other physical properties of cement systems need to be carried out to fully assess the impacts of nanoparticles.

Lastly, another example of where nanotechnology made a tremendous impact on commercial building materials is synthesis of nano-paint. For example, Krishnamoorthy et al. [117] developed a multifunctional graphene oxide (GO) nanopaint by incorporating GO sheets in an alkyd resin of the paint. The prepared GO nanopaint exhibited enhanced corrosion-resistant behavior in both acidic and high-salt-content solutions as well as substantial inhibition of the bacterial growth on its surface. This in-situ biofouling test results demonstrated incorporating the nanoparticles into the conventional paint materials produce significant performance benefits. Another study also concluded that preparation of titanium oxide (TiO2) nanopaint by embedding the TiO2 nanoparticles in alkyd resin matrix exhibited substantially enhanced antibacterial properties against a wide range of different types of bacterial strains [118]. Others also reported similar findings of enhanced corrosion-resistant behavior and anti-bacterial properties of nanoformulated paints [119–124]. Clearly, results from various studies demonstrate that these new coating formulation of nanopaint to be of tremendous value to researchers and industry. In conclusion the result of nanopaint characterization and performance evaluation opens up a new promising field of study and building materials for next generation.

### **4. Conclusion**

This review highlights the diversity in naturally occurring and engineered nanoparticle in various environments. Given the production of engineered nanoparticles is expected to increase significantly in forthcoming years with more applications and productions, the information provided herein review provide an important baseline from which to interpret future environmental change. Clearly the impacts and effects of nanoparticles on the bacterial toxicity, cement materials,

**347**

**Author details**

Union, New Jersey, USA

\*Address all correspondence to: haj@kean.edu

provided the original work is properly cited.

School of Environmental and Sustainability Sciences, Kean University,

© 2021 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,

Juyoung Ha

*Novel Applications of Nanoparticles in Nature and Building Materials*

well as fate and transport behavior of them in the nature.

agricultural practices, and sequestration of contaminants cannot be generalized because the physico-chemical reactions occurring at the nanoparticle surfaces depend on a wide range of environmental conditions. Further work should continue to focus on the speciation, biogeochemical behavior and ecotoxicological impacts of both natural and engineered nanoparticles to understand the long-term effects as

The author would like to thank beamline scientist for assistance with data collection at Lawrence Berkeley National Laboratory (Berkeley, CA, USA) and Stanford Synchrotron Radiation Lightsource (Stanford, CA, USA). The author also wishes to thank Kean University Foundation office for financial support and the anonymous reviewers and the editors for the comments which served to strengthen

*DOI: http://dx.doi.org/10.5772/intechopen.97668*

**Acknowledgements**

the manuscript.

*Novel Applications of Nanoparticles in Nature and Building Materials DOI: http://dx.doi.org/10.5772/intechopen.97668*

agricultural practices, and sequestration of contaminants cannot be generalized because the physico-chemical reactions occurring at the nanoparticle surfaces depend on a wide range of environmental conditions. Further work should continue to focus on the speciation, biogeochemical behavior and ecotoxicological impacts of both natural and engineered nanoparticles to understand the long-term effects as well as fate and transport behavior of them in the nature.
