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

Authors: IBRAHIM, NAEEMAH - Universiti Putra Malaysia; RASHID, UMER - Universiti Putra Malaysia; HAZMI, BALKIS - Universiti Putra Malaysia; Moser, Bryan; ALHARTHI, FAHAD - King Saud University; LALTHAZUALA ROKHUM, SAMUEL - National Institute Of Technology Silchar; NGAMCHARUSSRIVICHAI, CHAWALIT - Chulalongkorn University

Submitted to: Fuel
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2022
Publication Date: 2/14/2022
Citation: Ibrahim, N.A., Rashid, U., Hazmi, B., Moser, B.R., Alharthi, F.A., Lalthazuala Rokhum, S., Ngamcharussrivichai, C. 2022. Biodiesel production from waste cooking oil using magnetic bifunctional calcium and iron oxide nanocatalysts derived from empty fruit bunch. Fuel. 317. Article 123525. https://doi.org/10.1016/j.fuel.2022.123525.
DOI: https://doi.org/10.1016/j.fuel.2022.123525

Interpretive Summary: This research reveals that a new catalyst obtained from biomass is suitable for production of biodiesel from low-cost, low-quality feedstocks such as waste cooking oil. Normally low-quality feedstocks require expensive pretreatment before they can be converted to biodiesel due to the presence of free fatty acids and other impurities. With this new catalyst, the pretreatment procedure is unnecessary. The catalyst can also be recovered and reused, which is another advantage over the traditional biodiesel production process. Overall, biodiesel was prepared from waste cooking oil in high yield and the resulting fuel properties were within the ranges specified in important biodiesel fuel standards. These results will be important to biodiesel producers, distributors, and end-users (customers) because a new biodiesel fuel was described that exhibits favorable fuel properties. This research may ultimately improve market penetration, availability, and public perception of domestically produced agricultural fuels such as biodiesel, thus affording greater national independence from imported petroleum-based fuels.

Technical Abstract: Magnetic bifunctional nanocatalyst supported on activated carbon (AC), CaO-Fe2O3/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 µmol g-1 and 2653 µmol 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 °C 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 1H-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 mm2s-1 and flash point of 134 °C.