Optimization of improved biodiesel production from used cooking oil and soyabean oil blend using NaOH and CH3ONa as homogeneous catalyst via ethanolysis

Abstract

The production of eco-friendly fatty acid ethyl esters (FAEEs) has gained significant interest as a cleaner energy pathway that can reduce the environmental pollution associated with conventional fossil fuel. In this context, the present study aims to investigate an optimized approach for improved biodiesel production from a blended feedstock of used cooking oil (UCO) and soybean oil via ethanol-based transesterification. The utilization of UCO provides an effective pathway for waste valorization and cost reduction, while soybean oil contributes to improved reaction stability. Ethanol was utilized as a renewable, bio-sourced solvent to ensure a greener production process, generating improved biodiesel (FAEEs) with superior fuel properties such as higher cetane numbers, elevated flash points (safer handling), enhanced lubricity and better cold flow behavior. Two homogeneous catalysts, sodium hydroxide (NaOH) and sodium methoxide (CH3ONa) were employed to evaluate their catalytic performance. The transesterification process was systematically optimized by varying key reaction parameters. The highest FAEEs yield (90.34 %) was achieved at an ethanol to oil molar ratio (12:1), catalyst loading (0.75 wt%), reaction temperature (50 ℃) and reaction time (50 min) and stirring speed 400 rpm using CH3ONa catalyst. Overall, this study is expected to demonstrate an efficiency and sustainable pathway for improved biodiesel production using a combined waste and edible oil system.