Characterization of zeolitic imidazole framework (ZIF-8) catalyst for potential biodiesel production from waste cooking oil (WCO)

Heteropoly acids (HPAs) catalysts prove effective in waste cooking oil biodiesel production, considering their high density of Brønsted acidic sites, exhibit significant resilience to elevated levels of free fatty acid (FFA) and moisture content. However, the separation of HPA catalysts after biodiesel production is challenging due to their homogeneous catalytic nature. This study aims to develop magnetic vanadium-substituted HPA-based ZIF-8 composites to create a catalyst for biodiesel production from WCO that is more efficient and easier to separate. In this work, a range of analytical methods was utilized to characterize the catalyst, such as Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), high-resolution transmission electron microscopy (HRTEM), and a vibrating sample magnetometer (VSM). The successful incorporation of HPA acid into the magnetite ZIF-8 nanocomposite was indicated by prominent bands in the FTIR analysis, and this formation was further validated by EDX analysis. The VSM results also revealed that the nanocomposite has good magnetic responsiveness, facilitating catalyst separation and recycling. The magnetic ZIF-8 composites functionalized with H6PV3MoW8O40 demonstrated significant potential for sustainable biodiesel production from WCO. © The Authors, published by EDP Sciences.