Renewable Energy, Vol.159, 873-884, 2020
Wollastonite decorated with calcium oxide as heterogeneous transesterification catalyst for biodiesel production: Optimized by response surface methodology
CaO is efficient in catalyzing transesterification for biodiesel production, but its industrial application is inherently restricted by active sites leaching. To address this drawback, CaO is decorated into wollas-tonite to prepare the stable Ca/wollastonite catalyst. Microwave-assisted transesterification is used to produce biodiesel from palm oil, which effectively accelerates the reaction rate and improves the con-version efficiency. The Ca/wollastonite-0.8 catalyst with the mass ratio of CaO to wollastonite of 0.8 performs well with the fatty acid methyl ester (FAME) yield of 97.59%. Also, this catalyst is highly stable, where the FAME yield of 87.30% could be obtained for the fifth reused cycle. CaO is evenly dispersed on the wollastonite surface and the total basicity is high to 0.281 mmol g(-1). Meanwhile, transesterification parameters are optimized by response surface methodology with central composite design (RSM-CCD) and the maximum FAME yield of 98.46% is achieved at reaction temperature of 64.2 degrees C, molar ratio of methanol to palm oil of 15.54 and mass ratio of catalyst to palm oil of 9.21 wt% for 3 h. Besides, the mass ratio of catalyst to palm oil is the primary variable. Wollastonite is demonstrated to be feasible to enhance the stability of CaO in catalyzing transesterification. (c) 2020 Elsevier Ltd. All rights reserved.