A review of sulfonic group bearing porous carbon catalyst for biodiesel production

Global environmental concern and the diminishing of fossil fuel escalated the seek for the development of renewable alternative fuels such as biodiesel. Biodiesel can be produced via transesterification and esterification reactions, expedited with a suitable homogeneous or heterogeneous catalyst. Heterogeneous catalyst offers high activity and high selectivity; and this is due to the chemical and physical properties of the catalyst. Heterogeneous catalyst can be produced from various sources such as metal oxides and its derivatives; and bio-wastes containing carbon sources which are heterogeneous in nature. Lately, the utilization of sulfonated carbon acid catalyst becomes increasingly attractive due to its advantages and potential to replace homogeneous and heterogeneous catalysts in the biodiesel manufacturing industry. The catalyst is environmentally benign and can effectively convert free fatty acid to alkyl ester. Sulfonated carbon acid catalyst can be prepared by incorporating sulfonation agent which contains sulfonic group into the carbonaceous material. The performance of sulfonated carbon acid catalyst is highly dependent on the treatment condition and its starting material. This review focuses on the recent invention and use of the sulfonic group bearing porous carbon heterogeneous catalysts for biodiesel production.