Smart utilization of jatropha ( Jatropha curcas Linnaeus) seeds for biodiesel production: Optimization and mechanism

Abstract Jatropha curcas Linnaeus ( Jatropha curcas L.) seeds have been found to be an ideal sustainable and low-cost source of catalyst and oil feedstock for biodiesel production. Jatropha cake, remained dregs after jatropha curcas oil (JCO) extraction, has been treated by two different techniques; calcination and potassium hydroxide (KOH) activation to be used as novel heterogeneous catalysts for the transesterification reaction. The effect of calcination and KOH activation on the jatropha cake has been characterized. The basic strength and basicity of the catalysts have been determined as well. The effect of different operating conditions has been studied using JCO and waste cooking oil (WCO) to evaluate the efficiency of the catalysts. The catalysts produced higher biodiesel yield using JCO than WCO. In the case of using JCO, the two catalysts produced close biodiesel yield. Calcined jatropha cake (CJC) has been chosen as the optimum catalyst for its better reusability and lower preparation cost than KOH activated jatropha cake (KJC). The optimum operating conditions of the JCO transesterification process has been determined as 60 min reaction time, 6:1 methanol to oil molar ratio, 1 wt.% catalyst loading, 400 rpm and 60 °C. Biodiesel production yield of JCO was achieved to 94 and 96% with CJC and KJC catalysts.