Catalytic Performance of Biomass Carbon-Based Solid Acid Catalyst for Esterification of Free Fatty Acids in Waste Cooking Oil

A series of carbon-based solid acid catalysts were prepared from bagasse using a carbonization-sulfonation method and employed to catalyze esterification of oil with methanol to produce biodiesel. The physical and chemical properties of the biomass carbon catalysts were characterized by FTIR. The pretreatment of bagasse, carbonization temperature, sulfonation temperature and time, as well as the catalytic performance were systematically investigated. The results indicated that the catalysts prepared from bagasse with dilute acid hydrothermal treatment showed the best performance. For the catalysts, the acid value of waste cooking oils was decreased to 1 mg KOH/g, and FFA conversion reached 94.4 % after reaction for 4 h under optimized reaction conditions. The catalysts also showed better stability than traditional homogeneous catalysts.