Heterogeneous Catalysis Transesterification of Waste Cooking Oil (WCO) and Parametric Optimization

Waste cooking oil (WCO) is considered to be a potential feedstock for biodiesel due to its low cost, availability in avoiding the food-for-fuel competition of the same oil resources, and also associated with WCO disposal. Hence, the WCO was chosen for this study to investigate the transesterification reaction of microwave energy pretreated WCO using heterogeneous catalyst derived from chicken bones from the calcination temperature of 900 °C (C900). WCO and catalyst characterization were performed. Two models; alkali heterogeneous catalysis transesterification and microwave energy pretreated alkali heterogeneous catalysis transesterification, were designed of 62 experiments to investigate the effect of five reaction variables; Methanol to oil molar ratio, catalyst concentration, reaction temperature, reaction time and microwave heating time. The interaction effects of reaction variables were studied using statistical tool of Central Composite Design (CCD) technique of Response Surface Methodology (RSM). It is found that reaction temperature and reaction time are the significant variables for heterogeneous catalysis transesterification whereas reaction time, microwave heating time and C900 concentration were dominant variables to the FAME yield. The optimum FAME yield of microwave energy pretreated transesterification was at 91.94 % and qualitatively higher than that of alkali heterogeneous catalysis transesterification which gained 98.308 %. The FAME yield conditions proved that microwave energy can improve the transesterification and enhance the product yield up to 3.38 times higher than alkali heterogeneous catalysis transesterification within a shorter length of time