Biodiesel production in an autoclave reactor using waste palm oil and coconut coir husk derived catalyst

The present study investigates biodiesel production from waste palm oil (WPO) using coconut coir husk (CCH) derived solid acid catalyst. The catalyst was prepared by the direct in-situ concentrated sulfuric acid impregnation. The presence of active sites, such as sulfonic, carboxylic, and phenolic OH functional groups on the catalyst was confirmed by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The highest biodiesel yield of 89.8% was obtained under optimum conditions of 10 wt % catalyst, 12:1 methanol:oil (molar ratio), after 3 hat 130 degrees C and 500 rpm, in a laboratory autoclave reactor. It was found that biodiesel yield increases with increasing reaction temperature, reaction time, and catalyst loading, up to an optimum value. The catalyst can be reused for four cycles and the biodiesel yield was >77%. Relatively higher activity may be due to the high acid density of the catalyst due to the presence of hydrophilic functional groups bonded to the hydrophobic carbon structure. It was found that, kinematic viscosity (2.9 mm(2) s(-1)), pour point (-6 degrees C), heating value (38.1 MJ kg(-1)), and oxidation stability (3 h) of the produced biodiesel are in accordance with the international standards. Therefore, the produced biodiesel can be used. (C) 2018 Elsevier Ltd. All rights reserved.