Metal loading on CaO/Al2O3 pellet catalyst as a booster for transesterification in biodiesel production

The enhancement in the catalytic activity by using metal loading on CaO/Al2O3 pellet catalysts (M-CaO/Al2O3) for transesterification of palm oil with a 12:1 methanol-to-oil molar ratio and 10 wt% of catalyst loading and stirring speed of 600 rpm at a reaction temperature of 65 degrees C was revealed. FAME yields at 6 h reaction time using K-CaO/Al2O3, Sr-CaO/Al2O3, Fe-CaO/Al2O3, Li-CaO/Al2O3, and CaO/Al2O3 pellet catalysts were 88.8, 85.2, 67.0, 84.0, and 78.7%, respectively. M-CaO/Al2O3 pellet catalysts can promote the initial rate, initial TOF, and FAME yield since the metal loading on the CaO/Al2O3 pellet catalyst changes the environment of surface oxygen to increase lattice oxygen (O2-) as Lewis basic site. This work highlighted the role of O2-in the basicity and initial TOF with a linear correlation for metal oxide pellet catalyst. Although the K-CaO/Al2O3 pellet catalyst gave the highest FAME yield, the highest leaching of the active species was observed. Therefore, the high catalytic activity and stability of the Sr-CaO/Al2O3 pellet catalyst confirmed that there is more potential to drive toward continuous biodiesel production in the industry.