DOI: https://doi.org/10.55373/mjchem.v24i2.97

Keywords: Response surface methodology; waste cooking oil; transesterification, biodiesel

Abstract

Optimization of reaction parameters for biodiesel production is crucial to develop a more efficient and cost-effective system in the biodiesel industry. The transesterification reaction is affected by several factors, which are alcohol to oil molar ratio, reaction temperature, reaction time, and catalyst loading. In this study, the Response Surface Methodology (RSM) was utilized to obtain the optimal conditions for maximizing biodiesel yield. RSM using Box-Behnken experimental design that consists of 30 runs (number of experiments) and three blocks was developed to determine the optimal conditions of key parameters, such as (A) methanol:oil ratio (20-40); (B) catalyst loading [0.25-2% (wt/l)]; (C) reaction temperature (50-70°C); and (D) reaction time (1-15 hours). The ANOVA analysis suggested that the quadratic model is significant as the p-value for the model was < 0.0001 and the large F-value of 37.70. The lack of fit p-value of 0.0928 (p-value is not significant) implies that the model fitted all the data. The R2 value of 0.9760 indicates that the model fitted the experimental data. Based on the F-value and p-value of the significant model terms, methanol:oil molar ratio has the largest effect on biodiesel yield compared to other parameters. The optimum conditions whereby the maximum biodiesel yield of 35.45% was obtained were methanol to oil molar ratio of 34:1; reaction temperature of 68.4 ⁰C; reaction time of 11.9 h; and 1.125 wt% catalyst loading. In terms of interaction, AB, AC, AD, BC, BD, and CD were found to be insignificant model terms as their p-values were higher than 0.05.