Microwave-assisted in-situ transesterification of Spirulina platensis to biodiesel using PEG/MgO/ZSM-5 magnetic catalyst

In this study, PEG/MgO/ZSM-5@Fe3O4 magnetic catalyst was synthesized using polyethylene glycol (PEG) as a mediator, and was applied to the microwave-assisted in-situ transesterification of Spirulina platensis with ethanol. The effect of different proportion of mediator on catalyst performance was investigated. The composition, structure, morphology, specific surface area, magnetization and basicity of the catalysts were all characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), vibrating sample magnetometer (VSM) and Hammett indicator. The catalytic performance evaluation results showed that the highest yield of biodiesel could reach 95.8% under the optimum reaction condition using 15PEG/MgO/Z@Fe3O4 catalyst. In addition, the catalyst can be reused for six times without leaching of active components, which still had a high conversion of biodiesel. Finally, the physicochemical properties of the biodiesel were also tested, which were in accordance with GB and EN standards.