Study of pH influences on the performance of Na-loaded NbOPO4 solid acid catalyst for biofuel production

Abstract

This study reports on the development, preparation, and performance test of NbOPO4 solid acid catalyst for biofuel production from vegetable oil. NbOPO4 catalyst was synthesized by sol-gel method using NbCl5, H2SO4, and citric acid as the precursor solutions and chelating agent, respectively. Dependent variables in the study were calcination time of 5 h; NbOPO4 loading of 2%; transesterification time of 3 h; reaction temperature at 65-70°C and oil mass of 30 g. Whereas, the catalyst pH of 2, 4, 6, 9, and Na impregnation ratio of 20-50% were set as independent variables. The catalyst morphology was analysed by Scanning Electron Microscopy, catalyst elements was detected by Electron Dispersive X-Ray and X-Ray Diffractometer was used to characterize the crystallinity degree of the catalyst. The performance of the catalyst was evaluated from a transesterification reaction for biofuel production. The highest biofuel yield of 98,5% was obtained in the reaction using catalyst with a pH of 4 and Na impregnation ratio of 30%. The density obtained was 0,860 gr/cm3 confirming that the produced biofuel complies with the SNI. It can be concluded that Na-loaded NbOPO4 can be a promising alternative catalyst in biofuel production.