Microwave-Assisted Transesterification of Waste Cooking Oil using Zinc Ferrite Catalyst for Biodiesel Production

Spinel nanomaterial of ZnFe₂O₄ has been successfully synthesised and its high crystallinity is confirmed by x-ray diffraction analysis in the Fd3‾m space group with crystallite size of around 37.96 nm. The agglomerated nature of the sample is confirmed through SEM analysis and compositional analysis using EDS. The maximum yield of 94.66% biodiesel is obtained at 15 min, 50°C temperature, 6 weight % catalyst, and 6:1 ethanol: oil conditions. The FTIR analysis and ¹H-NMR analysis of waste cooking oil and biodiesel of different yields confirm the different functional groups exist in the sample and the biodiesel. The physio-chemical properties of the biodiesel match well with the literature values. The reusability of the ZnFe₂O₄ confirms the yield of 80.9% after 3 cycles under the same reaction conditions.