Preparation, characterization, kinetic and thermodynamic studies of MgO-La2O3 nanocatalysts for biodiesel production from sunflower oil

Abstract

A series of MgO-La2O3 nanocatalysts were prepared via a co-precipitation method and used for biodiesel production from sunflower oil. The results showed that with increasing Mg/La weight percent the catalytic activity increases obviously. Also the results showed that the catalyst with Mg/La=60wt.% (based on weight of La) is an optimal nanocatalyst. The best operational conditions were the CH3OH/oil=18/1 at 338K with mechanical stirring 700rpm for 5h. Furthermore, the optimal nanocatalyst showed high catalytic activity for biodiesel production and the biodiesel yield reached 97.7% under the optimal conditions. Furthermore, this nanocatalyst was used for 4 runs in biodiesel production without significant decrease of catalytic performance. Also kinetic and thermodynamic of reaction has been studied in the presence of optimal nanocatalyst. From the kinetic and thermodynamic studies, Ea=77.6kJ·mol−1, A=3.5×107l·mol−1s−1, ΔrHθ=162kJ·mol−1K−1, ΔrSθ=0.54kJ·mol−1K−1 were obtained. Characterization of catalysts was carried out by using scanning electron microscopy (SEM), X-ray diffraction (XRD), temperature programmed desorption (TPD), Fourier transform-infrared spectroscopy (FT-IR) and N2 adsorption–desorption measurement methods.