Catalytic transesterification of triglycerides and esterification of free fatty acids underpins sustainable biodiesel production, wherein efficient heterogeneous catalysts are sought to replace mineral acids. A robust, magnetic core-shell SO4/Mg-Al-Fe3O4 catalyst was synthesised by stepwise co-precipitation, encapsulation, and surface functionalisation. The resulting magnetically-separable catalyst has a surface area of 123 m2 g-1, uniform 6.5 nm mesopores, and a high total acid site loading of 2.35 mmol g-1. Optimum conditions for the (trans)esterification of waste cooking oil (WCO) over the sulfated solid acid catalyst were 95 °C, a methanol:WCO molar ratio of 9:1, and 300 min reaction to achieve 98.5 % FAME yield. Esterification of oleic acid to methyl oleate resulted in an 88 % yield after 150 min under the same reaction conditions. The magnetic solid acid catalyst exhibited good thermal and chemical stability and enabled facile catalyst separation post-reaction and the production of high quality biodiesel.
Bibliographical noteCrown Copyright © 2019 Published by Elsevier B.V.
Funding: Ministry of Higher Education and Scientific Research of the Kurdistan Regional Government for funding this study under the Human Capacity Development Program (HCDP).
Gardy, J., Nourafkan, E., Osatiashtiani, A., Lee, A. F., Wilson, K., Hassanpour, A., & Lai, X. (2019). A core-shell SO4/Mg-Al-Fe3O4 catalyst for biodiesel production. Applied Catalysis B: Environmental, 259, . https://doi.org/10.1016/j.apcatb.2019.118093