Preparation of biodiesel from waste frying oil using a green and renewable solid catalyst derived from egg shell



Biodiesel was produced from waste frying oil using calcium oxide derived from the calcination of egg shell as a heterogeneous base catalyst. The catalyst was characterized by X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller analysis, scanning electron microscopy, and energy-dispersive atomic X-ray spectrometry. The effects of reaction variables such as methanol/oil molar ratio, amount of catalyst, reaction temperature, and reaction time on biodiesel yield were investigated. The activity of the egg shell-derived CaO was compared with the commercial CaO. A high biodiesel yield of 95.05% and conversion of 96.11% were obtained at 3 wt % catalyst (based on oil weight), methanol/oil molar ratio of 9:1, reaction temperature of 65°C, and reaction time of 3 h. The structure of biodiesel was characterized by FTIR, and the biodiesel conversion was determined by 1H nuclear magnetic resonance spectroscopy. © 2014 American Institute of Chemical Engineers Environ Prog, 34: 248–254, 2015