Optimization and Characterization of Bio-Diesel Production from Rubber Seed Oil Using Response Surface Methodology

The global pursuit of decarbonization and net-zero emissions necessitates sustainable and renewable energy alternatives, with biodiesel emerging as a viable solution. This study focuses on utilizing rubber seed oil (RSO), a non-edible and abundant feedstock, for biodiesel production. RSO addresses the dual challenge of reducing reliance on fossil fuels and minimizing competition with food resources. However, the high free fatty acid (FFA) content of RSO presents a significant barrier to efficient biodiesel synthesis through traditional alkaline transesterification. A two-step process, acid esterification followed by alkaline transesterification, was employed to overcome this limitation. The process was optimized using Box-Behnken Design (BBD) within the Response Surface Methodology (RSM) framework. The ideal conditions for maximum biodiesel yield included a methanol-to-oil molar ratio of 5:1, catalyst concentration of 1.19%, reaction time of 79 minutes, and reaction temperature of 61.5°C. Under these parameters, a maximum biodiesel yield of 97.09% was achieved. The resultant biodiesel, rubber seed oil methyl ester (RSOME), was characterized in accordance with ASTM and EN standards. RSOME exhibited superior thermal stability, high flash and fire points, and notable calorific properties, making it a competitive alternative to conventional diesel fuel. By valorizing an underutilized waste resource, this study not only contributes to the advancement of sustainable biodiesel production but also aligns with global decarbonization initiatives. The findings underscore the potential of RSO-derived biodiesel as a critical component of future renewable energy strategies, supporting environmental sustainability and economic viability.