Review on progress in magnetic heterogeneous-based catalysts for biodiesel production

To combat climate change and the issues associated with fossil fuels, we must transit to bio-renewable energy sources, such as biofuel, which is obtained by transesterification of triglycerides. Conventional homogeneous acid or base catalysts are efficient, but difficult to separate and generate toxic waste. Magnetic heterogeneous catalysts that add active catalytic sites to a magnetic core (Fe₃O₄) are designed to be easily recovered after the reaction using an external magnetic field, which reduces the catalyst loss and purification process. Thus, making the biodiesel production process much more environmentally friendly and sustainable. These catalysts are effective for various feedstocks, especially low-quality oils with high FFA content and are grouped into acidic, basic or bifunctional types. This review provides an overview of the various synthesis methods employed to produced magnetic catalysts, progresses made in research on transesterification of oil using various magnetic catalysts and their application in biodiesel production and future direction in the biofuel industry.