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

¹ Department of Chemical Engineering, Lee Kong Chian Faculty and Science (LKC FES), University Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, 43000 Kajang, Selangor, Malaysia
² Centre of Advanced and Sustainable Materials Research (CASMR), Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Kajang 43000, Selangor Malaysia
³ Department of Chemical Engineering, Faculty of Engineering, Technology and Built Environment, UCSI University (Kuala Lumpur Campus), No. 1, Jalan Menara Gading, UCSI Heights (Taman Connaught), 56000 Cheras, Kuala Lumpur, Malaysia
⁴ School of Chemical Engineering, Collage of Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
⁵ Department of Physics, Faculty of Science, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia
⁶ Nanomaterials Synthesis and Characterization Laboratory, Institute of Nanoscience and Nanotechnology, Universiti Putra Malaysia, 43400, UPM Serdang, Selangor, Malaysia

^* Corresponding author: lyng@utar.edu.my

Abstract

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 HPAbased 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 Fouriertransform infrared spectroscopy (FTIR), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), highresolution 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.