A cleaner approach with magnetically assisted reactor setup over CaO-zeolite/Fe3O4 catalyst in biodiesel production: evaluation of catalytic performance, reusability and life cycle assessment studies.

Abstract

This study reports the magnetic catalyst constructed by incorporating magnetite (Fe3O4) within zeolite-supported calcium oxide (CaO) in conventional and magnetic reactors for heterogeneous catalytic biodiesel production. The CaO-zeolite/Fe3O4 catalyst demonstrated remarkable characteristics, including a substantial surface area, acid-base properties, and high magnetization. These attributes enable efficient transesterification of used cooking oil (UCO) with high free fatty acid (FFA) content and facilitate the easy separation of the solid catalyst by utilizing magnetic force once the reaction is complete. In the conventional reactor, employing a 3 wt% catalyst dosage and a 5:1 methanol to oil molar ratio, the maximum biodiesel yield reached 93.64% after 240 min at 55 °C. Meanwhile, the magnetic reactor yielded a maximum biodiesel yield of 96.91% when operating for 300 min, using a 4 wt% catalyst dosage, 5:1 methanol to oil molar ratio, and maintaining a reaction temperature of 55 °C. The catalyst reusability result did not indicate an appreciable reduction in biodiesel yield in 4 cycles with the magnetic reactor. The life cycle assessment (LCA) study also revealed fewer negative effects of biodiesel production by using a magnetic reactor on the environment. The efficient utilization of CaO-zeolite/Fe3O4 catalyst in the magnetic reactor has shown great potential for industrial application.