Process optimization and kinetic study for biodiesel production from non-edible sea mango (Cerbera odollam) oil using response surface methodology

This paper presents the process optimization and kinetic study for the heterogeneous transesterification of non-edible sea mango (Cerbera odollam) oil using response surface methodology central composite design (RSMCCD). The four transesterification process variables studied are; reaction temperature (333–453 K), reaction time (1–5 h), molar ratio of oil to methanol (1:6–1:14) and amount of sulfated zirconia catalyst (2–10 g* g−1) (catalyst/oil). From this study, it was found that reaction temperature gave the most significant effect on the conversion of sea mango oil to fatty acid methyl esters (FAME), followed by reaction time. There were also significant interaction effects between reaction temperature and amount of catalyst, and between reaction time and amount of catalyst. Based on the optimized condition, highest conversion of 97.5% was predicted using the following variables; reaction temperature = 423 K, reaction time = 3 h, molar ratio of oil to methanol = 1:12 and amount of catalyst = 8 g* g−1. Experimental verification on the predicted optimum condition gave an actual conversion of 94.1%. The small error between the predicted and actual optimum conversion (3.5%) indicated that the model was valid and accurate in representing the actual experimental values and also in predicting conversion at any condition within the range studied. The developed kinetics model suggested a 1.1th order reaction with activation energy of 36.03 kJ mol−1 and frequency factor of 5.56 × 102 min−1.