Texture evolution of mesoporous SAPO-34 via a hard-templating sono-hydrothermal method for biodiesel production: Influence of carbon materials on nanocatalyst design

Abstract

To solve the challenges of diffusion of large molecules of oil into the SAPO-34 pores, secondary carbon and polymeric templates are used in sonohydrothermal synthesis method. Structure of the catalysts was estimated by BET, XRD, TPD, EDX, FESEM, HRTEM, and FTIR analyses. The best pore distribution was obtained for the catalyst synthesized by charcoal active, in which the conversion was 83 % for the esterification reaction of oleic acid. To increase the activity of this catalyst, 5% CeO2 was accommodated on it by sono-solvothermal method which resulted in 94 % conversion. Kinetic studies showed that for all synthesized catalysts, the degree of esterification reaction was of the first order and CeO2 loaded sample had the highest rate constant, equal to 0.0013 min−1. By increasing the pore radius and acidic strength of the catalyst, the reaction rate constant increases due to the overcoming the penetration of large oil molecules and increased acidic activity.