Biochar production from waste rubber-wood-sawdust and its potential use in C sequestration: Chemical and physical characterization

Abstract

Biochars have received increasing attention because of their potential environmental applications such as soil amending and atmospheric C sequestration. In this study, biochar was produced from waste rubber-wood-sawdust. The produced biochars were characterized by Brunauer-Emmett-Teller (BET) gas porosimetry, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). Pyrolysis temperature was shown to have a strong influence on both thermal and chemical characteristic of biochar samples. The experimental data shows that the biochar samples can absorb around 5% water by mass (hydrophilic) at lower temperatures (<550 °C), and that lignin is not converted into a hydrophobic polycyclic aromatic hydrocarbon (PAH) matrix. At higher temperatures (>650 °C), biochar samples were thermally stable and became hydrophobic due to the presence of aromatic compounds. Carbon content (over 85%) increased with increasing temperature, and showed an inverse effect to the elemental ratios of H/C and O/C. The very low H/C and O/C ratios obtained for the biochar indicated that carbon in this material is predominantly unsaturated. BET results showed that the sawdust derived biochars have surface areas between 10 and 200 m2 g−1 and FTIR indicated an aromatic functional group about 866 cm−1 in most of the samples. The rate of CO2 adsorption on sawdust derived biochar generally increased with increasing temperature from 450 to 650 °C but then decreased with increase in the production temperature. Derived biochar represents a potential alternative adsorbent for C sequestration.

Using Magnetized (Fe3O4 / Biochar Nanocomposites) and Activated Biochar as Adsorbents to Remove Two Neuro-Active Pesticides from Waters

“…A band at 1584 cm -1 was attributed to aromatic material, and a shoulder at 1154 cm -1 was associated with the structures of cellulose and hemicellulose carbohydrates. Ghani et al 25 characterized biochar produced from rubber wood waste and reported that the IR spectra showed the formation of aromatic products with lower hydrogen contents, compared to the original material. In the present work, AB was obtained using a pyrolysis temperature of 600 °C, while MB was produced at 400 °C, so AB was more liable to changes in chemical composition due to carbonization, relative to the EH parent material.…”

“…Hemicellulose pyrolysis products include non-condensable gases (CO, CO 2 , H 2 , and CH 4 ), low molecular weight compounds (carboxylic acids, aldehydes, alkanes, and ethers), and water. 25 An intense decomposition peak in the region 200-400 °C was observed for the TAN precursor material used to produce MB, which could be attributed to the decomposition of polyphenolic compounds. The production of MB using a pyrolysis temperature of 400 °C would therefore lead to decomposition of these compounds.…”

“…This indicated that the cellulose had been degraded in the pyrolysis. 15,25 The decomposition of lignin is considered to be a slow process, because part of the molecule consists of benzene rings that begin to decompose across a wide temperature range of 160-900 °C. 25,26 A peak in the range 400-500 °C, which was only observed for MB, was attributed to the loss of lignin.…”

“…15,25 The decomposition of lignin is considered to be a slow process, because part of the molecule consists of benzene rings that begin to decompose across a wide temperature range of 160-900 °C. 25,26 A peak in the range 400-500 °C, which was only observed for MB, was attributed to the loss of lignin. Riegel et al 27 evaluated the use of different heating rates for pyrolysis of black wattle cultivated in Rio Grande do Sul.…”

Characteristics of slow pyrolysis biochars produced from rhodes grass and fronds of edible date palm

“…They found by BET and FTIR that an increase in process temperatures results in higher surface area, more development of aromatic compounds and a decrease in aliphatic groups. Ghani et al [10] evaluated the properties of biochar from waste rubber-wood-sawdust by pyrolysis between 450 °C and 850 °C, founding by BET analysis that the total surface is lower than 10 m 2 /g for lower temperatures and around 200 m 2 /g for higher temperatures. Kim et al [11] evaluated the properties of biochar from pitch pine produced by fast pyrolysis at different temperatures (300-500 °C); they obtained BET surface areas between 3.0 and 175 m 2 /g that increased with the pyrolysis temperature; from the FTIR spectra, they found that the O-H stretch peak (3600-3200 cm -1 ) decreases in the spectra for biochar.…”