Novel heterogeneous base nanocatalysts supported on a spray dried gamma alumina applying optimized production of biodiesel from waste cooking oil

Abstract

In this study, K/Fe2O3/γ-Al2O3 nanocatalyst was synthesized and used in the transesterification of waste cooking oil for biodiesel production. The effects of three operating parameters – reaction time, catalyst concentration, and methanol-to-oil molar ratio –on the biodiesel yield were studied using response surface methodology (RSM). A reduced cubic equation was established as a suitable and best-fitting model to predict the response with high accuracy. The results showed that the catalyst loading significantly affected the fatty acid methyl ester (FAME) yield. The highest biodiesel yield of 99% was obtained under the optimal conditions of reaction time 7.84 hours, catalyst concentration 4.60 wt.%, and methanol-to-oil molar ratio 9.73. The catalyst recyclability was evaluated in two successive cycles. Different characterization methods such as XRD (X-Ray Diffraction), SEM (Scanning Electron Microscope), BET (Brunauer, Emmett and Teller), TGA (Thermogeravimetric Analysis), GC-MASS (Gas Chromatography - Mass Spectrometry) were utilized for the synthesized catalysts and final biodiesel products. The synthesized heterogeneous magnetic catalysts were easily separated from the biofuel product. This ease of catalyst separation, in comparison with homogeneous catalyst, effectively reduces industrial biofuel production costs.