Preparation of rare earth modified clay-based solid acid catalysts and their application for biodiesel production from soybean oil

In this study, catalysts of SO42-/ZrO2-La2O3-Hangjin 2# clay (SZLa-HJ) and SO42-/ZrO2-CeO2-Hangjin 2# clay (SZCe-HJ) were prepared with La and Ce as cocatalysts respectively. The activity of the catalysts was evaluated based on the conversion of biodiesel, while examining the effects of rare earth doping, sulfuric acid concentration, and calcination temperature. Central composite design optimized the preparation procedure for SZLa-HJ and SZCe-HJ. NH3-TPD, Py-FTIR, EDS, TG, DAT, SEM, XRD and XPS techniques were employed to describe it. The results showed that adding La or Ce to SO42-/ZrO2 Hangjin 2# clay effectively controlled the distribution of acid sites by increasing both Bronsted and Lewis acid sites in a way that maintained more Lewis acid sites in the catalyst; this was favorable for transesterification reaction.