Mitigation of SrO catalyst leaching and recyclability in biodiesel transesterification: comprehensive parameter optimization and characterization via FTIR spectroscopy

Leaching is the primary issue of heterogeneous catalyst deactivation in a liquid phase. The irreversibility of catalyst leaching presents a significant challenge to sustaining the activity and reusability of the catalyst. The characteristics of the synthesized catalysts were analyzed by FTIR, TGA-DSC, FESEM-EDS, BET, and XRD, followed by parametric analysis to evaluate the effect of the reaction variable on the catalyst leaching in the synthesized biodiesel by FTIR spectroscopy and ash content test. The FTIR results showed that the optimization of the reaction parameters could effectively reduce the SrO catalyst leaching. The ash content was reduced by 97.3%, and the FAME yield of 93.9% was achieved under the optimized reaction conditions of 1 wt.% catalyst loading, 15 min of reaction time, 9:1 Me: Oil molar ratio, and 65 °C reaction temperature. The catalytic recycling study showed an increase in catalyst recycling to the fifth cycle under optimized conditions. The GC-MS and FT-IR analysis of the biodiesel showed its high quality and physicochemical characteristics matched those of the ASTM standard.