4.1. Proximate and ultimate analysis of CC and GNS samples

The proximate and ultimate analysis of the CC and GNS are shown in Table 1. From table, it is observed that the both the agricultural biomass have relatively less ash (0.94 and 1.79%, respectively); higher content of VM (80.73 and 79.54%, respectively) with FC (14.97 and 14.13%, respectively), and GCV (14.74 and 14.03 MJ/kg).

The contents of carbon, oxygen and hydrogen in all the feedstocks are (C, 47.78 and 45.50%; O, 46.14 and 48.45%; H, 5.87 and 5.44%, respectively). Further the lower content of hetero elements (N, 0.19 and 0.46% and S, 0.11 and 0.15%, respectively) in CC and GNS are advantageous for environmental disquiets. Also agricultural biomass at thermo-chemical treatment releases less toxic gases (such as, SOx and NOx gases) comparable with fossil fuels. Than which we can say biomass are environment friendly and clean energy source.


The pH values of coconut coir char (CCCh) and ground nut shell char (GNSCh) varies from (8.04–11.08) and (7.70–10.41) respectively are also increase with increase in pyrolysis temperature. Biochars with higher pH and significant surface area are suggestive for their better application potential in reducing the soil acidity and treating the soil and water contaminated with toxic elements and organic pollutants [22–24]. Similarly the heating value (GCV) for these biochars also varies in the range 16.40–23.12 MJ/kg and 17.58–23.50 MJ/kg respectively [25]. The increase in the GCV of the biochars is attributable to the heat endorsing components (like

Biochar Derived from Agricultural Waste Biomass Act as a Clean and Alternative Energy Source of Fossil Fuel…

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4.3. Proximate and ultimate analyses of CCCh and GNSCh at different pyrolysis

in CCCh and GNSCh varies from 45.25–84.32% and 49.91–85.06%, respectively.

Proximate and Ultimate analysis of CCCh and GNSCh are shown in Table 3. volatile matter (VM) content of biochar decreases with increase in pyrolysis temperature i.e., 32.48–5.56% and 30.80–6.48% in case of CCCh and GNSCh respectively. The presence of lignin in the agricultural biomass waste material can partially resist pyrolytic decomposition at lower temperature but not in case at temperatures as high as 950C [26]. The CCCh and GNSCh showed a high ash content, and this may be because of the partial change in the composition promoted by a possible relation between organic and inorganic constituents [26]. It can be seen that biochars with higher content of ash generally have the lower values of fixed carbon and vice versa. Similarly fixed carbon (FC)

Further the ultimate analysis of CCCh and GNSCh varies significantly in respect of C, H, N, S,

Figure 1 (a) and (b) shows the FTIR spectra of CC, GNS, and their derived char at different pyrolysis temperatures. These graphs are plotted against wave numbers and transmittance

CCCh 350 32.48 22.27 45.25 49.73 1.14 4.50 0.18 44.45

GNSCh 350 30.80 19.29 49.91 56.20 0.86 5.61 0.09 37.24

Table 3. Proximate\* and ultimate analysis of CCCh and GNSCh at different pyrolysis temperature.

550 21.80 19.78 58.42 64.40 1.01 3.78 0.16 30.65 750 6.38 15.62 78.05 80.69 0.79 2.55 0.16 15.81 950 5.56 10.12 84.32 87.45 0.47 2.02 0.17 9.89

550 19.56 15.34 65.10 71.78 0.79 3.46 0.09 23.88 750 8.67 10.21 81.12 83.49 0.58 2.39 0.07 13.47 950 6.48 8.46 85.06 87.78 0.43 2.11 0.06 9.62

VM% Ash% FC % C % N % H % S % O %

FT-IR Analysis of the CC, GNS, and their derived char at different pyrolysis temperature.

FC, C, and H) present in these agricultural wastes biomass.

and O contents, which is tabulated in Table 3.

Biochars Pyrolysis temperature ( C)

\*Air dried basis.

temperature

Table 1. Proximate and Ultimate analysis (as received basis) of CC and GNS.


Table 2. Physiochemical characteristics of CCCh and GNSCh at different temperatures.

#### 4.2. Yield, pH, and GCV of the biochars

Physiochemical characteristics like, Yield%, pH, and GCV of the derived biochars at different temperatures from CC and GNS are shown in Table 2. From this table it is observed that there is relatively higher percentage of yield at 350C of pyrolysis, which further decreases with increase in temperature up to 950C. From this table, it is observed that there is relatively higher yield of chars at lower temperature of pyrolysis, which further decreases progressively with increase in temperature. Reduction in the bio-char yield at high temperatures is attributable to undergoing the secondary reactions of the bio-char formed during the primary pyrolysis, which lead to the formation of liquid and gaseous products at the cost of solid char [18]. The energy given to the biomass at high temperature may exceed the bond breaking energy which supports the release of the volatile components of the biomass in the form of gases resulting in less char yield [19]. The reduction in the bio-char yield with increase in pyrolysis temperature is also reported by other workers [20, 21]. As with the biomass feedstocks, the char products have energy values roughly related to their carbon contents. Release of this energy by combustion can again be considered as renewable and is largely carbon neutral; the carbon returned to the atmosphere as carbon dioxide is the same as would otherwise have resulted from biomass decomposition. If the char product is not burnt, but retained in a way that the carbon in it is stable, then that carbon can be equated to carbon dioxide removed from the atmosphere and sequestered.

The pH values of coconut coir char (CCCh) and ground nut shell char (GNSCh) varies from (8.04–11.08) and (7.70–10.41) respectively are also increase with increase in pyrolysis temperature. Biochars with higher pH and significant surface area are suggestive for their better application potential in reducing the soil acidity and treating the soil and water contaminated with toxic elements and organic pollutants [22–24]. Similarly the heating value (GCV) for these biochars also varies in the range 16.40–23.12 MJ/kg and 17.58–23.50 MJ/kg respectively [25]. The increase in the GCV of the biochars is attributable to the heat endorsing components (like FC, C, and H) present in these agricultural wastes biomass.
