Sustainable conversion of waste corn oil into biofuel over different forms of synthetic muscovite based K+/Na+sodalite as basic catalysts; Characterization and mechanism

Abstract

Novel types of sodalite enriched in both K+ and Na+ ions were synthesized from muscovite at different time intervals (24 h (SD-24), 48 (SD-48), and 72 h (SD-72)). The samples displayed changes in their morphologies and observable increment in the surface area, total basicity, and ion exchange capacity with increasing the synthesis period. The samples were used as potential basic catalysts in the transesterification of the waste products of corn oil. The produced sodalite sample after 48 h (SD-48) achieved the best catalytic activity and the best biodiesel yield (95.4%). This yield was obtained after 120 min at 70 C using 16:1 methanol-to corn oil molar ratio and 4 wt., % SD-48 loading. The achieved yields by SD-24 and SD-72 are 84.7% and 90.5%, respectively. The higher activity of SD-48 (95.4%) than SD-24 (84.7%) related to its high surface area and total basicity. The lower activity of SD-72 (90.5%) than SD-48 (95.4%) related to its very high ion exchange capacity which increases the saponification reactions in the existence of K+ and Na+ ions at high concentrations. The used SD-48 catalyst shows significant regeneration belongings and reused in five cycles producing valuable biodiesel yields. Technically, the resulted biodiesel from the waste product of corn oil over SD-48 is of acceptable international qualification which prompts the large-scale use of the catalyst.