Potassium Halides - Impregnated Eggshell as a Heterogeneous Nanocatalysts for Biodiesel Production

In this study, Potassium halides-doped Calcium Oxide (CaO) was synthesized as heterogeneous nanocatalysts for transesterification of waste cooking oil. The chicken eggshell wastes were used as raw materials to synthesize calcium oxide. The calcium carbonate (CaCO3), principal constituent in the eggshell, was changed to calcium oxide by calcining at 873 K for 4 h. After that, the calcium oxide was impregnated with potassium iodide (KI) and potassium fluoride (KF) via wet impregnation method. The textural properties of the solid oxide catalyst were characterized by base strength, field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The basic strengths of the catalysts were determined applying Hammett indicator. The yield of nanocatalysts evaluated by using the prepared catalysts in waste cooking oil transesterification with methanol for at 338 K 2 h. the catalytic activity depends on several factors such as, base strength, Impregnation and calcination processes and impregnated Compound. The formed KCaF3 was the major active element for the catalytic activity in KF/CaO nanocatalyst, however, this activity was not observed in KI/CaO nanocatalyst. For the reason of presenting of this component, the Ca2+ in KF/CaO acts as a stronger Lewis acid and exhibits high catalytic activity. Biodiesel yield for KF/CaO catalyst and KI/CaO was 91.18 % and 87.69%, respectively.