Catalytic high-yield biodiesel production from fatty acids and non-food oils over a magnetically separable acid nanosphere

Biodiesel, a kind of promising alternative renewable energy, is of great significance in replacing conventional fossil energy resources. Herein, for purpose of improving the preparation technology of biodiesel through efficient and convenient modifying the well-dispersion of active sites of magnetic catalysts, Fe3O4@SiO2-SO3H (P) and Fe3O4@SiO2-SO3H (S) catalysts synthesized respectively via co-precipitation and solvothermal preparation methods, were successfully employed for biodiesel production. Fe3O4@SiO2-SO3H (S) bearing the uniform core shell nanometer microsphere structure and good dispersibility that was beneficial to the substrates touch with efficient acidic sites along with acid density of 1.8 mmol g(-1), was demonstrated to furnish biodiesel in a higher yield of 97.8 %, which was better than that of Fe3O4@SiO2-SO3H (P) (88.2 % yield) at 65 degrees C within 4 h. The kinetic study revealed that Fe3O4@SiO2-SO3H (S)-catalyzed esterification fitted the first order model along with a low activation energy (47.9 kJ/mol), further clarifying the reason for the good catalytic performance of Fe3O4@SiO2-SO3H (S). More importantly, thermal filtration and reusability experiments confirmed the catalyst heterogeneous catalytic behavior and good reusability. The involved reaction mechanism was also interpreted, in which the Fe3O4@SiO2-SO3H (S) acid catalyst was determined to be favorable for accelerating oleic acid conversion to biodiesel via density functional theory (DFT) calculations. Finally, given economic and environmental perspective, by analyzing the potential of the industrial application of Fe3O4@SiO2-SO3H (S) and comparing its catalytic performance with other reported catalysts, its promising value in terms of transforming fatty acids and non-food oils into biodiesel could be anticipated.

Automated summary

This study successfully prepared biodiesel using two magnetic catalysts, Fe3O4@SiO2-SO3H (P) and Fe3O4@SiO2-SO3H (S), with Fe3O4@SiO2-SO3H (S) showing higher yield and good reusability. Kinetic study demonstrated its excellent catalytic performance with a low activation energy, indicating great potential for industrial application.