Incorporation of CuO on the αFe2O3 nanoparticles as a heterogeneous catalyst for conversion of waste cooking oil into biodiesel

This study focused on generating biodiesel from waste cooking oil (WCO) employing an αFe₂O₃/CuO nanocatalyst synthesized via a co-precipitation method. Several characterization techniques, including FTIR, XRD, SEM-EDX, BET, and TEM analyses, were applied to scrutinize the features of the fabricated nanocatalyst. The results confirmed the successful incorporation of CuO into the αFe₂O₃ structure. BET analysis further revealed that the addition of CuO nanoparticles significantly enhanced the catalyst's surface properties, increasing the number of active sites available for transesterification reactions. Besides, the αFe₂O₃/CuO nanocatalyst exhibited a specific surface area of 334 m²/g, highlighting its high surface availability for catalytic activity. The process was statistically optimized using response surface methodology (RSM) with a Box-Behnken design (BBD) to assess the influence of critical reaction parameters. Vital parameters evaluated included temperature (50-70 °C), methanol/WCO molar ratio (8-14 mol/mol), and catalyst loading (1-3 wt%). Moreover, ANOVA results indicated that the methanol/WCO molar proportion had the most remarkable effect on biodiesel production efficiency, with an F-value of 337.11. Under optimal conditions reaction time of 3 h, methanol/WCO molar ratio of 11, αFe₂O₃/CuO dosage of 2 wt%, and temperature of 60 °C a highest biodiesel yield of 94.27% was achieved. Additionally, the reusability assessment of the αFe₂O₃/CuO nanocatalyst demonstrated notable stability, with only a 12% reduction in efficiency observed over seven cycles. This research demonstrates that αFe₂O₃/CuO nanocatalysts, owing to their unique properties, have the potential to serve as highly effective heterogeneous catalysts for transesterification.