Development of Heterogeneous Basic Catalysts Supported on Silica for the Synthesis of High Quality Bio-Diesel from Waste Cooking Oil

Abstract

Effect of addition of CaO and ZrO₂ to MgO/SiO₂ catalyst, which is effective for synthesis of High Quality BioDiesel (HiBD) was investigated using atmospheric agitated reactor at 430 °C and LHSV = 0.3 h^-1. Binary MgOCaO/SiO₂ and MgO-ZrO₂/SiO₂ catalysts and ternary MgO-CaO-ZrO₂/SiO₂ catalyst were prepared by the incipient wetness impregnation method. Physical properties of these catalysts were characterized by XRD and BET methods. Both the fatty acids and the triglycerides in waste cooking oil were converted into hydrocarbon gases, CO, CO₂, water and hydrocarbon oil. CaO- and/or ZrO₂-added catalysts gave higher CO₂ yields than MgO/SiO₂ alone, and showed lower acid values. These observation indicates that the added oxides promote the decarboxylation reactions. Iodine values also decreased to some extent by the addition of these oxides.