Valorization of cassava peelings into biochar: Physical and chemical characterizations of biochar prepared for agricultural purposes

Abstract

The sustainable management of waste generated by human activities is now a global concern. The valorization of waste by pyrolysis is a recycling method aiming at obtaining a biochar which can contribute to improve the fertility of soils and to limit the use of chemical fertilizers. It is in this perspective that the present study aims to valorize cassava peelings into biochar. Slow pyrolysis was applied for biochar production using an artisanal oven at 400 °C and the obtained biochar was characterized. FTIR analysis revealed that cassava peelings biochar consists of hydrophilic surface functional groups (mainly -OH and -COOH). EDX analysis showed that the biochar is mainly composed of carbon (78.65%), oxygen (18.65%), phosphorus (0.26%), potassium (1.91%), calcium (0.30%), magnesium (0.13%), silicon (0.10%), and nitrogen (1.14%), was determined by Kjeldahl method. SEM micrographs revealed that the biochar has a rough and porous surface. The BET surface area and BJH average pore diameter of the biochar are 341.11 m2/g and 1.44 nm, respectively. X-ray diffraction showed that the biochar is amorphous and consists largely of calcite (CaCO3). C/N ratios of 68.51; O/C of 0.23 and H/Corg of 0.03 were also obtained. These results show that the biochar produced has acceptable qualities and can be used as a soil amendment.