Synthesis and Characterization of Novel CaO-based Heterogeneous Catalysts for Efficient Biodiesel Production from Waste Cooking Oil

In this study, a series of novel basic heterogeneous catalysts (Ca-based mixed Ce and Cu oxides) with various mass ratios were designed by co-precipitation method to be utilized in biodiesel, Fatty acid methyl ester (FAME) production via the transesterification process of waste oil under the following process conditions (i.e., methanol to waste cooking oil mass ratio of [13:1] at reaction temperature 75 o C for 5 h). The various binary mixed oxides were characterized by several techniques (e.g., Thermo-gravimetric analysis (TGA-DTG), powder X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area measurements, Fourier transform- Infrared (FT-IR) spectroscopy, and surface basicity by back titration). Biodiesel yield is estimated by gas chromatography (GC). The biodiesel optimum yield, of 95 and 94 % yield is achieved by 3CaO1CeO2@800 2 @800 oC and 3CaO-1CuO@800 o C catalysts under the reaction condition of 2% wt. catalyst loading level, methanol to waste oil molar ratio of [13:1], reaction temperature of 75 o C, and reaction time of 2 h for the former catalyst, while, catalyst loading of 2% for 1 h at 75 o C and [13:1] M:O molar ratio for the later one, respectively. The high catalytic activity may be attributed to the higher BET surface area and strong basic characteristics, which indicate more accessible active sites for the transesterification process on the catalyst surface. Furthermore, the catalytic materials were reactivated and reused for two to three reaction cycles. The physical characteristics of the produced FAME are found to fulfill the American standard for testing materials (ASTM D-6751) international standards.: