**4. Physical and chemical characterization of DCP**

#### **4.1 Physical characterization**

#### *4.1.1 Proximate analysis*

*Humic Substances*

biosorption properties.

under normal environmental conditions.

to standard desorption and re-adsorption cycles and finally the spent DCP can be employed as a landfill material in deteriorated soils. Because of its strong chelating properties, any residual metallic ions are well-bonded to DCP and do not leach out

This study concludes that DCP is affordable and adaptable due to its Combo nature and its acceptability lies in its working mechanism based on HSAB concept of sorption [45]. DCP has a great potential in the field of water decontamination,

DCP is naturally available bioorganic, complex, polymorphic humified fecal matter of cow and is enriched with minerals, carbohydrates, fats, proteins, bile pigments, aliphatic - aromatic species such as HA, FA, Ulmic acid and Humus etc. Many functional groups such as carboxyl, phenols, quinols, amide, enhance its

The total characterization of DCP has been carried out for its physical, chemical as well as microbiological properties. DCP was provided by Keshav Shrushti, Research Centre on Cow products (Thane, India). Fresh cow dung was collected by efficient workers and due safety measures were taken to avoid any toxic and heavy metal contamination during collection. Cow dung is basically the feed residues digested by symbiotic bacteria residing within the animal rumen. The net effect of digestion in the rumen is the conversion of dietary materials to a mixture of fatty acids (mainly acetic, butyric and propionic acids), gases (primarily CO2 and CH4 which are voided by eructation) and microbial biomass [46]. The innate existence of different microbes, beetles and other dung related arthropods bring about

There are different pigments and lipids in cow dung which are related to its color and typical odor. The bile pigment biliverdin is mainly present in cow dung (herbivore) giving it its green color. Also, bile salts give dung its emulsifying properties by which it confers hydrophilic coat to the droplets, otherwise of its hydrophobic nature [48]. It is also flourished with number of microorganisms as well as some classes of Arthropods. To ascertain passive biosorption by dead microbes, it is necessary to have an overall account of microbiological consortium of fresh dung. Cow dung consists of approximately 60 species of bacteria, including species from the following genera - Bacillus, Actinomycetes, Corynebacterium, Pseudomonas, Cellulomonas, Flavobacterium, Lactobacillus, Serratia, and Alcaligens [49, 50]. It also includes *Escherichia coli* and Staphyloccocus aureus along with roughly 100 species of protozoa and yeasts including Saccharomyces and Candida spp. Cow dung also contains certain fungi like Trichoderma and Aspergillus spp. Due to the profusion of diverse micro flora, it has considerable

The presence of petroleum utilizing microbes is indicative of high percentage of Hydrocarbon in the environment and cow dung too has a great abundance of this microbiota [52]. The presence of these microbes is also dependent on the geographical and environmental milieu. This microbial consortium enables cow dung with considerable potentials for biodegradation and biotransformation of oil - petroleum products and other pollutants as well as it further contributes to plant production

In order to select any new material for a process, the material should fulfill the theory of 3A's, which stand for affordability, acceptability, and adaptability. DCP is affordable due to its free availability and its supply is not hampered by climatic

industrial water treatment and in abatement of water pollution.

**3. Dry cowdung powder - DCP: The best of waste**

humification of the organic matter present in cow dung [47].

potential for biodegradation and biotransformation [51].

and in many biogeochemical processes [53].

**28**

The total characterizations of DCP for its physical and chemical properties have been designed. The physical characterization has been carried out by proximate analysis **Table 1** as per the standard procedure given by American Public Health Association (APHA). The elemental, structural, morphological analysis, and thermal stability of DCP has been conducted at Sophisticated Analytical Instrument Facility- Indian Institute of Technology (SAIF- IIT), Mumbai. Physical parameters such as moisture content, ash content, mesh size, fiber content, etc. have been evaluated. Biochemical analysis of DCP for its amino acid, carbohydrate and other contents has been carried out by Radial Chromatography.

#### *4.1.2 The elemental composition by XRF and CHNSO Analyzer*

The DCP has been characterized using XRF technology for its quantitative as well as qualitative elemental composition as shown in **Table 2.** For the complete elemental composition, complimentary to XRF technique, C, H, N, S, (O), has also been obtained, **Table 3** shows the same.


**Table 1.** *Proximate analysis of DCP.*


#### **Table 2.**

*Elemental composition of dry cow dung by XRF.*


#### **Table 3.** *C,H,N,S,O analysis of DCP.*

#### *4.1.3 Scanning electron microscopy (SEM)*

The SEM patterns **Figure 1(a-i)**, shows that DCP has some fibrous structure with some holes and small openings on the surface. Also, the surface of DCP is heterogeneous, rough, porous and with dentations. It shows the presence of cell debris of some prokaryotic cells. The holes and openings on DCP increase the contact area and facilitate the pore diffusion during adsorption. SEM study of DCP also affirms the theory of metal ion diffusion into porous biomass**.** According to this theory, metal ions can either be present on the surface of the biomass or can permeate into the expanded pores, which make desorption of metal ions difficult [54].

### *4.1.4 Thermal gravimetric analysis (TGA) and differential thermal analysis (DTA)*

For the verification of DCP to be thermally stable, *Thermal Gravimetric Analysis* (TGA) as well as *Differential Thermal Analysis* (DTA) have been carried out. **Figure 2** for TGA reveals that, the moisture content of DCP is 8.928% and it is quite stable till 230°C. After 350°C, the weight loss of DCP is about 50%. This can be attributed to simple process such as drying, or from more complex chemical reactions that liberate gasses, such as structural water release, structural decomposition, carbonate decomposition, sulfur oxidation, and fluoride oxidation. Thus, it can be concluded that DCP is thermally stable.

**31**

**Figure 1.** *SEM of DCP.*

*Dry Cowdung Powder - Novel Unearthed Humus: Sustains Water-Food-Energy Nexus*

**Figure 3** of DTA shows two endothermic peaks near the region of 48-50°C, which is a small peak and second at 230–270°C is a broad peak. It also describes two exothermic peaks, one smaller peak at 170–175°C and a broader peak from 300°C onwards. This study supports our observation that the biosorption of metal ions on DCP decreases on increasing the temperature. In case of DTA, the mean progression of the combustion profile and the limits of different temperature ranges delineating the phases of thermal decomposition of DCP using 2.311 mg, within a temperature range of 25–420°C with the heating rate of 10°C min–1 as can be seen in Graph 2. There are two endothermic and one exothermic peak on curve, corresponding to respective decomposition steps. The first step is in the temperature range between 39.09°C & 60°C and might correspond to the evaporation of water incorporated in or adsorbed onto DCP, being accompanied by a little loss in weight and is signified by first endothermic peak. A small exothermic peak is observed around at 180–185°C, it may be due to some crystallization process involved during heat transfer process [55]. The second endothermic peak is observed in the temperature range from around 214.88–265°C and is accompanied by some weight loss which may be due to loss of polar functional groups. The phenolic OH groups are eliminated between 250°C [56]. Around 280°C the decline in weight is seen which may be caused by decarboxylation and unsaturation [57]. The decomposition of carboxylic, phenolic,

*DOI: http://dx.doi.org/10.5772/intechopen.98476*

*Dry Cowdung Powder - Novel Unearthed Humus: Sustains Water-Food-Energy Nexus DOI: http://dx.doi.org/10.5772/intechopen.98476*

**Figure 1.** *SEM of DCP.*

*Humic Substances*

**Table 2.**

**Table 3.**

*C,H,N,S,O analysis of DCP.*

**30**

*4.1.3 Scanning electron microscopy (SEM)*

*Elemental composition of dry cow dung by XRF.*

can be concluded that DCP is thermally stable.

The SEM patterns **Figure 1(a-i)**, shows that DCP has some fibrous structure with some holes and small openings on the surface. Also, the surface of DCP is heterogeneous, rough, porous and with dentations. It shows the presence of cell debris of some prokaryotic cells. The holes and openings on DCP increase the contact area and facilitate the pore diffusion during adsorption. SEM study of DCP also affirms the theory of metal ion diffusion into porous biomass**.** According to this theory, metal ions can either be present on the surface of the biomass or can permeate into

the expanded pores, which make desorption of metal ions difficult [54].

**Element % Component** 3.104 Nitrogen 37.367 Carbon 5.142 Hydrogen 3.432 Sulfur 29.654 Oxygen

**Element %** Na 0.946 Mg 2.853 Al 1.684 Si 22.691 P 3.883 K 3.343 Ca 2.360 Ti 0.329 Mn 0.115 Fe 2.419 Cl 1.56 Cr 0.014

*4.1.4 Thermal gravimetric analysis (TGA) and differential thermal analysis (DTA)*

(TGA) as well as *Differential Thermal Analysis* (DTA) have been carried out. **Figure 2** for TGA reveals that, the moisture content of DCP is 8.928% and it is quite stable till 230°C. After 350°C, the weight loss of DCP is about 50%. This can be attributed to simple process such as drying, or from more complex chemical reactions that liberate gasses, such as structural water release, structural decomposition, carbonate decomposition, sulfur oxidation, and fluoride oxidation. Thus, it

For the verification of DCP to be thermally stable, *Thermal Gravimetric Analysis*

**Figure 3** of DTA shows two endothermic peaks near the region of 48-50°C, which is a small peak and second at 230–270°C is a broad peak. It also describes two exothermic peaks, one smaller peak at 170–175°C and a broader peak from 300°C onwards. This study supports our observation that the biosorption of metal ions on DCP decreases on increasing the temperature. In case of DTA, the mean progression of the combustion profile and the limits of different temperature ranges delineating the phases of thermal decomposition of DCP using 2.311 mg, within a temperature range of 25–420°C with the heating rate of 10°C min–1 as can be seen in Graph 2. There are two endothermic and one exothermic peak on curve, corresponding to respective decomposition steps. The first step is in the temperature range between 39.09°C & 60°C and might correspond to the evaporation of water incorporated in or adsorbed onto DCP, being accompanied by a little loss in weight and is signified by first endothermic peak. A small exothermic peak is observed around at 180–185°C, it may be due to some crystallization process involved during heat transfer process [55].

The second endothermic peak is observed in the temperature range from around 214.88–265°C and is accompanied by some weight loss which may be due to loss of polar functional groups. The phenolic OH groups are eliminated between 250°C [56]. Around 280°C the decline in weight is seen which may be caused by decarboxylation and unsaturation [57]. The decomposition of carboxylic, phenolic,

#### **Figure 2.**

*Thermogravimetric analysis spectra of DCP.*

carbonyl and alcoholic groups at higher temperatures have often been attributed to the thermal breakdown of aromatics. In the analytical conditions of TGA and DTA analysis (with a heating rate of 10°C min–1) aromatic structures can be formed from cyclic structures [58].

#### *4.1.5 Electron spin resonance spectroscopy*

The abundance and presence of unpaired electron and free radicals in the DCP has been assessed by ESR spectroscopy. The spectral information from **Figure 4** is not very vivid but explains that DCP contains some free radical biotic groups. The source of free radicals can be organic radicals of semi-quinine nature conjugated with extended aromatic systems or paramagnetic metal ions such as Fe, Mn and V [59]. Also, ESR data of IHSS samples do show free radical contents with g-values approximately around 2.000 and we have also obtained the g-value for DCP, around 2.000 in agreement with standard samples.

#### *4.1.6 Fourier-transform infrared spectroscopy (FTIR)*

As explained earlier the detailed information of various adsorptive functional groups of biosorbent is of great importance and DCP has been assayed for all the possible functionality present on it. There are various organic groups present on DCP such as carbohydrate, protein, lignin, cellulose etc. In case of carbohydrate, only carboxyl and sulphonate contribute majorly in the formation of metallic ligands. Similarly, in protein moiety the group such as carboxyl, sulphonate,

**33**

**Figure 4.** *ESR spectra of DCP.*

**Figure 3.**

*Dry Cowdung Powder - Novel Unearthed Humus: Sustains Water-Food-Energy Nexus*

*DOI: http://dx.doi.org/10.5772/intechopen.98476*

*Differential thermogravimetric analysis spectra of DCP.*

*Dry Cowdung Powder - Novel Unearthed Humus: Sustains Water-Food-Energy Nexus DOI: http://dx.doi.org/10.5772/intechopen.98476*

#### **Figure 3.**

*Humic Substances*

cyclic structures [58].

**Figure 2.**

*4.1.5 Electron spin resonance spectroscopy*

*Thermogravimetric analysis spectra of DCP.*

2.000 in agreement with standard samples.

*4.1.6 Fourier-transform infrared spectroscopy (FTIR)*

carbonyl and alcoholic groups at higher temperatures have often been attributed to the thermal breakdown of aromatics. In the analytical conditions of TGA and DTA analysis (with a heating rate of 10°C min–1) aromatic structures can be formed from

The abundance and presence of unpaired electron and free radicals in the DCP has been assessed by ESR spectroscopy. The spectral information from **Figure 4** is not very vivid but explains that DCP contains some free radical biotic groups. The source of free radicals can be organic radicals of semi-quinine nature conjugated with extended aromatic systems or paramagnetic metal ions such as Fe, Mn and V [59]. Also, ESR data of IHSS samples do show free radical contents with g-values approximately around 2.000 and we have also obtained the g-value for DCP, around

As explained earlier the detailed information of various adsorptive functional groups of biosorbent is of great importance and DCP has been assayed for all the possible functionality present on it. There are various organic groups present on DCP such as carbohydrate, protein, lignin, cellulose etc. In case of carbohydrate, only carboxyl and sulphonate contribute majorly in the formation of metallic ligands. Similarly, in protein moiety the group such as carboxyl, sulphonate,

**32**

*Differential thermogravimetric analysis spectra of DCP.*

**Figure 4.** *ESR spectra of DCP.*

**Figure 5.** *FTIR spectra of DCP.*

sulfhydryl, hydroxyl, phosphonate, thioester, secondary amine, imines participates in ligand formation [60] Lignin derivative contain an abundance of oxygen containing functional group such as phenolic, alcoholic and enolic structure which forms lignin- metal complexes. **Figure 5** and **Table 4** explains the same in brief. Also, the FTIR analysis of DCP after and before the metal ion adsorption has been carried out to confirm the biosorption process with the observed shifts in wavelength of functional group involved in biosorption.
