Pour point and yield simultaneous improvement of alkyl esters produced by ultrasound-assisted in the presence of αFe2O3/ZnO: RSM approach

alpha Fe2O3/ZnO nanoparticles were synthesized as a heterogeneous catalyst to produce biodiesel by transesterification of canola oil under ultrasonic irradiation. Nanocatalysts were characterized using XRD, FT-IR, SEM, TEM, BET, and CO2- TPD. The RSM and the BBD were employed to analyze the effect of variables. An acceptable agreement was achieved between the experimental and predicted data using RSM for yield (R2 = 0.9837) and pour point (R2 = 0.9901). Maximum yield and minimum pour point were obtained as 90.75% and -20 0C, respectively. The optimal reaction conditions were achieved at alcohol to triglyceride molar ratio, catalyst concentration, ultrasonic time, and alcohol type of 12:1 mol: mol, 2.53 wt% 30.98 min and 2-butanol, respectively. The incorporation of ZnO to alpha Fe2O3 improved the basicity of the nanocatalyst. Moreover, the alpha Fe2O3/ZnO nanocatalysts displayed a very good stability (83.19% yield) after 7 cycles. Kinetic studies indicated that the production rate of biodiesel corresponds well to the first-order equation.

Automated summary

The alpha Fe2O3/ZnO nanoparticles were synthesized as a heterogeneous catalyst for biodiesel production via transesterification of canola oil under ultrasonic irradiation. The incorporation of ZnO improved the basicity of the nanocatalyst, leading to good stability and high yield of biodiesel. Experimental and predicted data analysis revealed optimal reaction conditions for maximizing production efficiency.