Study of calcined eggshell as potential catalyst for biodiesel formation using used cooking oil

Eggshells were utilized as a cost effective catalyst to assist in biodiesel formation. Eggshells were calcined using different calcination conditions such as temperature and time. The eggshells underwent calcination under 1000 °C in which calcium carbonate was completely converted into calcium oxide under open air conditions. The calcined eggshell catalyst was characterized by X-ray diffraction (XRD). Then the eggshell derived CaO catalyst was subjected to transesterification of used cooking oil (UCO). The parametrics in the transesterification of used cooking oil such as a methanol to oil ratio, weight of catalyst and reaction temperature were evaluated. The optimum result exhibited a 4:1 methanol to oil ratio, 2wt % catalyst, and a 65 °C reaction temperature within two hours. Pure calcined CaO acted as the control of the experiment that was subject to the most optimum eggshell derived catalyst transesterification conditions. The catalytic activity for both the pure calcined CaO and the calcined eggshell derived catalyst were comparable. The biodiesel formation was identified by gas chromatography mass spectrometry (GC-MS).