A comparative study on synthesis and characterization of biochars derived from lignocellulosic biomass for their candidacy in agronomy and energy applications.

Summary: This study has dealt with the synthesis and characterization of biochars produced from three biomasses, viz. water hyacinth (whole plant and its components), yellow oleander, and sugarcane bagasse, and their comparative assessment for potential application in agronomy and energy production. The pyrolysis was carried out in a fixed batch reactor at 350°C and 550°C with a heating rate of 20°Cmin−1. Biochars were characterized for proximate and ultimate (elemental) analysis, and also using standard techniques (SEM, EDX, TGA, BET, XRD, and FTIR). Biochars produced at 550°C from all the feedstock had good properties (carbon content: 39.09‐80.74%, pH: 7.36‐10.42, calorific value: 16.98‐30.18 MJ kg−1, and ash content: 0.89%‐21.78%). Moreover, relatively low atomic ratios (H/C 0.25‐0.47 and O/C 0.15‐1.11) of all biochars indicated their potential as solid fuel. XRD results showed the presence of amorphous and crystalline structures, and minerals like sylivite, quartz, kalsilite, and tridymite in the biochar. Biochar produced from sugarcane bagasse at 550°C possessed the best properties: fixed carbon (77.42%), bulk density (0.13 kg/m3), brunauer–emmett–teller (BET) surface area (17.78 m2/g), pore size (12.86 nm), total pore volume (0.025 cm3/g), calorific value (30.18 MJ kg−1), ash content (1.16%), and moisture content (2.03%). [ABSTRACT FROM AUTHOR]