Biodiesel production from waste cooking oil by application of perovskite structure catalyst: Experimental and theoretical evaluation of strontium stannate catalyst activity

Abstract

In this study, transesterification process of waste cooking oil to produce biodiesel was investigated using perovskite catalyst, strontium stannate. Different characterization tests were used to identify the synthesized catalyst structure. Powder x-ray diffraction and fourier transform infrared spectroscopy of synthesized samples confirmed the formation of SrSnO3. Energy-dispersive x-ray spectroscopy and relative amounts of elements proved the formation of SrSnO3, and elemental mapping showed perfect distribution in the sample. Brunauer-Emmett-Teller method determined that the mean pore’s diameter is 25.408 nm. To investigate the catalytic performance, four critical parameters, including operating time, temperature, methanol to oil molar ratio and catalyst loading and their interaction effects were investigated. Also, response surface methodology was implemented to optimize the parameters. According to data analysis and based on transesterification process optimization, the maximum yield of biodiesel production (98.75%) was attained at 40.3 min, 72.9 °C, methanol to oil molar ratio of 18.65:1, and catalyst loading of 2.94 wt%. The results of this study showed that using strontium stannate as a catalyst has a significant impact on the production of biodiesel using waste cooking oil. The catalyst reusability has been investigated for 6 cycles, and it showed a small decrease, and the efficiency of biodiesel production in the sixth cycle reached about 89%, which is still significant.