Dolomite incorporated with cerium to enhance the stability in catalyzing transesterification for biodiesel production

Stability of the calcined dolomite in catalyzing transesterification during the reused cycles is poor due to the leaching out of the calcium active sites and dolomite is incorporated with cerium to overcome the drawback in this study. Three different methods of the wet impregnation, direct wet impregnation and solid mixing are used for the cerium incorporation, where the wet impregnation method with the cerium to calcium molar ratio of 0.6 is preferred for the best catalytic performance. The maximum biodiesel yield of 97.21% is achieved with the catalyst to oil mass ratio of 0.05 and methanol to oil molar ratio of 15 at 65 °C for 2 h. Attributed to the strong synergistic effect between CaO and CeO2, the leaching out of the calcium active sites from the cerium incorporated dolomite catalyst into the liquid transesterification products is greatly reduced and the biodiesel yield of 88.63% is obtained for the fifth reused cycle. The physical properties of the produced biodiesel are in accordance with the ASTM D 6751 or EN 14214 standard to guarantee its industrial application.