Optimization of ZnO incorporation to αFe2O3 nanoparticles as an efficient catalyst for biodiesel production in a sonoreactor: Application on the CI engine

Abstract

Pure αFe2O3 and αFe2O3 1-x/ZnO x (x = 0, 40 and 80 wt%) nanoparticles were synthesized using the sol-gel method and, then, tested for biodiesel production from canola oil with the sonochemical process. Characterization of nanocatalysts was carried out using XRD, BET-BJH, SEM, EDX, TEM, TGA, CO2-TPD, and Raman spectroscopy analyses. The results of CO2-TPD and Raman confirmed that the dispersion of ZnO is well incorporated in the structure of αFe2O3, increasing the basicity of the nanocatalyst via generating oxygen vacancy. The response surface methodology (RSM) and Box behnken design (BBD) were utilized to analyze the effect of parameters. The best incorporation of ZnO on catalytic performance was observed in x = 47.24 wt%. Besides, the size and shape of the optimized nanocatalyst were 40 nm and needle/hexagonal, respectively. The optimization of the reaction demonstrated the maximum biodiesel yield of 94.21%. Reusability investigation of the optimum catalysts even after seven consecutive cycles revealed that αFe2O3/ZnO nanoparticles have higher catalytic performance and are more stable than pure αFe2O3. The results of the engine test indicate that the rich oxygen amount of canola biodiesel leads to considerable improvements in fuel combustion conditions, particularly in B30 (30% biodiesel-70% diesel).