Porous biochar production from microwave pyrolysis of sugarcane bagasse biomass with KOH addition

Abstract

ABSTRACT Biomass-based porous carbons have diverse structures and typically exhibit good multifunctionality. Therefore, compared to direct combustion, using pyrolysis to convert agricultural waste into biochar is an environmentally friendly and effective treatment method. Preparing biomass-derived porous carbon materials (PCMs) through microwave is challenging, as biomass rarely absorbs microwave energy and necessitates the inclusion of additional microwave absorbers. In this study, a silicon carbide crucible was designed to simplify the microwave pyrolysis process, and sugarcane bagasse-based porous carbon (GZKM) was prepared using a microwave pyrolysis coupled with KOH activation method without adding additional microwave absorbers. A detailed study was conducted on the yield, surface morphology, and pore structure of biochar obtained from different temperatures (700, 750, 800, 850, and 900 °C) and different mass ratios of sugarcane bagasse to KOH (0, 4:1, 2:1, 1:1, and 1:2). The results indicated that as the pyrolysis temperature and KOH addition increased, the yield of biochar gradually decreased from a highest value of 31.41 wt% to a lowest value of 11.8 wt%. The specific surface area (SBET) of GZKM initially increased and then decreased with the increase in pyrolysis temperature and KOH mass, reaching a maximum value of 889.41 m2/g. The results of this study can provide guidance for the reuse of sugarcane bagasse and the preparation of porous biochar, and can also be applied in fields such as electrocatalysts, batteries, biomedical materials, and wastewater treatment.