Thermochemical Synthesis of Mg-Al Ceramic Spinel as Support for MgO/MgAl2O4 Nanocatalyst Toward Conversion of Vegetable Oil to Green Fuel

A simple and economical thermochemical method was used for synthesis of MgAl2O4 spinel for the first time. After dispersion of MgO over the spinel surface as active phase, the new MgO/MgAl2O4 nanocatalyst was successfully used for the biodiesel production as a green fuel. The prepared nanocatalyst was analyzed by XRD, FESEM, EDX-Dot Mapping, BET-BJH and FTIR analyses. Finally, the synthesized sample was used for the biodiesel production for reaction conditions at 110 °C, catalyst to the feed ratio being 3%wt., molar ratio of alcohol to oil equals to be 12 for 3 hours reaction time. The results of the XRD analysis confirmed the successful synthesis of MgAl2O4 spinel and the FESEM images of the synthesized sample showed a uniform morphology with the formation of clusters. The BET-BJH analysis has shown that the synthesized sample had a pore size diameter and surface area of 5.9 nm and 84.76 m2/g respectively which are appropriate for the biodiesel production reaction. The results of these analyzes were in good agreement with the results of the synthesized nanocatalyst activity in the biodiesel production reaction, so that this sample achieved a good conversion of 92.6%. Also, after six times usage in the mentioned reaction conditions, the conversion for the synthesized sample was about 64%. However, it should be noted that the conversion remained almost constant in the third to sixth cycles. The results of this paper has shown that thermochemical-impregnation method, in addition to its simplicity and low cost, leads to synthesis of catalyst with favorable characteristics and industrialization capability.