Biodiesel production from waste cooking oil using magnetic bifunctional calcium and iron oxide nanocatalysts derived from empty fruit bunch

Magnetic bifunctional nanocatalyst supported on activated carbon (AC), CaO-Fe(2)O(3/)AC was synthesized via wet impregnation method and was utilized for catalytic transesterification of waste cooking oil (WCO). A series of characterization techniques were performed to determine acid-base properties, magnetism, thermal stability, crystallinity, chemical composition, surface properties, and morphology of the catalyst. The BET analysis showed that the CaO-Fe2O3 catalysts had specific surface areas and pore sizes (~5 nm) that were suitable for the transesterification reaction. The optimized catalyst, CaO(10%)-Fe2O3(10%)/AC, possessed significant acidity and basicity desorption of 18532 mu mol g(-1) and 2653 mu mol g(-1), respectively, which contributed to maximum biodiesel yield of 98.3% at the following reaction conditions: 3 wt%, catalyst loading, 18:1 methanol to oil molar ratio and at 65 ?& nbsp;for 3 h of reaction. Furthermore, the magnetism of CaO(10%)-Fe2O3(10%)/AC was 7.59 emu/g, which facilitated high recovery rates from the reaction mixture by magnetic decantation. Reusability experiments revealed a high catalytic stability (FAME yield > 80%) for at least six consecutive cycles. Biodiesel confirmation by Fourier transform infrared spectroscopy and H-1-nuclear magnetic resonance spectroscopy showed a strong C=O absorption band at 1774 cm(-1) and a singlet methoxy proton signal at 3.7 ppm. Lastly, fuel properties analysis met the American biodiesel standard ASTM 6751 with low kinetic viscosity of 3.42 mm(2)s(-1) and flash point of 134 ?.

Automated summary

A magnetic bifunctional nanocatalyst supported on activated carbon was synthesized and used for the catalytic transesterification of waste cooking oil. The catalyst showed significant acidity and basicity, which contributed to a high biodiesel yield. It also exhibited magnetism, facilitating the recovery of the catalyst from the reaction mixture. Reusability experiments demonstrated the catalyst's high stability, and the biodiesel produced met the American biodiesel standard.