Transesterification of Jatropha Oil to Biodiesel Using SrO Catalysts Modified with CaO from Waste Eggshell

Addition of SrO in combination with a hydration technique were used to modify eggshell-derived CaO catalysts for transesterification of Jatropha oil with methanol. A Box-Behnken design of experiment was employed to determine the optimal conditions. The results showed that the maximum methyl ester content of 99.71% could be achieved with the catalyst having 7 mmol/g of SrO at 65 °C, 89.8 min, MeOH:oil molar ratio of 27.6:1, and catalyst amount of 4.77 wt%. At these conditions, the catalyst remained active with methyl ester content of ca. 90% for several cycles and gradually deactivated due to the losses of active metals.