Effect Of Mole Ratio Of KOH/Bentonite Catalyst For Conversion Of Waste Cooking Oil To Methyl Ester Nur Ain Sharina Shukor,1, a) Noraini Hamzah,2
School of Chemistry and Environment, Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia
Abstract
Biodiesel is a sustainable and clean burning fuel that can be a substitute for conventional diesel. However, the production of biodiesel requires a higher cost compared to the conventional diesel. Hence, the cost of production can be reduced by using waste cooking oil (WCO) as feedstock. In this study, the production of biodiesel was carried out from waste cooking oil (WCO) via transesterification process and KOH/bentonite catalyst was used as a heterogeneous catalyst. A different molar ratio of KOH/bentonite catalyst was synthesised by impregnation of bentonite with potassium hydroxide (KOH) at 60 degree celsius for 6 hours. The ratios between KOH and bentonite were 1:2, 1:3, 1:4, 1:5, and 1:6. The characterization of both raw bentonite and KOH/bentonite catalyst were done using Thermogravimetric Analysis (TGA), Brunauer, Emmett, and Teller (BET), X Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscope (SEM). The decreasing of BET surface area in raw bentonite and KOH/bentonite and the presence of K2O phase in the XRD pattern indicates that there is a process of KOH impregnated bentonite. Moreover, from the analysis of SEM, it shows that the particle size between raw bentonite and KOH/bentonite is increasing due to the impregnation process. The high yield of FFA conversion was obtained at optimum molar ratio of KOH/bentonite 1:5, which was 27.55% under the reaction parameters of methanol to oil molar ratio of 6:1, the reaction temperature at 60 degree celsius, 3wt% of catalyst concentration, and a reaction time of 3 hours. Reusability test shows the performance of KOH/bentonite catalyst in the conversion of FFA was dropped from 27.55% to 13.73%. This research reveal the feedstock of waste cooking oil is a great potential to produce good quality of biodiesel.
