Sustainable utilization of waste palm oil and sulfonated carbon catalyst derived from coconut meal residue for biodiesel production

Abstract

In this study, an inexpensive, environmental benign acid catalyst is prepared using coconut meal residue (CMR) and employed for biodiesel production from waste palm oil (WPO). The total acid density of the catalyst is found to be 3.8mmolg^-1. The catalyst shows a unique amorphous structure with 1.33m²g^-1 of surface area and 0.31cm³g^-1 of mean pore volume. Successful activation is confirmed by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The highest biodiesel yield of 92.7% was obtained from WPO in an open reflux system using the catalyst. Results show that biodiesel yield increases with increasing methanol:oil (molar ratio) and reaction time up to an optimum value. It is found that the catalyst can be reused for at least four cycles for >80% biodiesel yield. Fuel properties of the produced biodiesel meet international biodiesel standards.

Keywords: Biodiesel; Carbon based solid acid catalyst; Coconut meal residue; Direct sulfonation; Waste palm oil.