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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]

Soil in embankments is often amended with several additives for supporting the vegetation growth on the side slopes. Biochar, a stable, nutrient loaded and moisture retentive material, could be amended to the embankment soils. The positive impacts of biochar on soil properties, soil water and nutrient retention, microbial activity and growth of crops are well established. However, the load-bearing capacity of biochar-amended soil which is utmost important for a material to be used in embankment is rarely reported in literature. The present study aims to investigate the shear strength and load-bearing capacity of biochar-amended soil for application in embankments. For assessing the shear strength and load-bearing capacity, California bearing ratio (CBR) and direct shear tests were conducted on bare and 5%, 10% and 15% (w /w) biochar-amended silty sand and pure sand. The results revealed that the biochar amendment decreased the dry unit weight (6–19%), and increased the shear strength (cohesion (c) and angle of internal friction (ϕ)) and load-bearing capacity of both the soils by 22–228% and 17–89% respectively. Further, the biochar amendment improved the vegetation root (34–108%) and shoot (29–157%) mass, ensuring the enhanced stability and protection (erosion). Thus, the results suggest the application of biochar-amended soil in embankments, however future field-scale trials are needed before application. [ABSTRACT FROM AUTHOR]