Statistical optimization of biodiesel synthesis from waste cooking oil using NaOH/ bentonite impregnated catalyst
Wısdom Chukwuemeke Ulakpa, Ruth O.E. Ulakpa, Emmanuel Oghenegare Eyankware, Michael Chika Egwunyenga
Abstract
In the present study, bentonite clay supported on sodium hydroxide catalyst was synthesized and its performance was evaluated for biodiesel synthesis from waste cooking oil. Impregnation procedure was used for the synthesis of NaOH/bentonite catalyst and the best catalyst was selected based on the yield of transesterification reaction. The catalyst characterization was done by Scanning electron microscope (SEM) to determine the morphology, and Fourier transform infrared (FTIR) analysis to determine the functional group. The synthesized catalyst was used to investigate the synthesis of FAME by varying the response parameters using central composite design of randomized response surface methodology (RSM-CCD). The transesterification was conducted with 9:1 methanol to oil, 4 wt% catalyst, reaction time of 4 h, temperature of 600 C, with stirring speed of 350 rpm. A biodiesel yield of 91.2% was obtained in continuous stirring speed of 350 rpm at 60ºC for 4 h and 9:1 methanol/oil molar ratio with 4 wt% of NaOH/bentonite catalyst. Investigations were done on how different reaction factors affected the biodiesel yield. The developed catalyst was found to have good catalytic activity. The developed catalyst was significant because it could be easily recovered and reused in successive cycles without significantly losing catalytic activity. The RSM was found to be a reliable statistical method for creating a respectable empirical model of the relationships between operational parameters and optimal operating conditions for future prediction. The fuel's physical and chemical qualities were measured, and they were found to be within safe ranges.