Effect of molybdenum promoter on performance of high silica MoO3/B-ZSM-5 nanocatalyst in biodiesel production

Biodiesel is a clean and renewable energy. In this study, biodiesel was produced through the esterification of free fatty acid (FFA) with methanol over the high silica B-ZSM-5 nanocatalyst. The parent nanocatalyst was synthesized by hydrothermal technique and the promoter was introduced by a multi-step wet impregnation method. XRD, FT-IR, BET, FE-SEM, EDX, TEM, and NH3-TPD analyzes characterized the textural and acidity properties of the nanocatalysts. The promoter was dispersed uniformly without significant framework destruction. The impregnation of molybdenum decreased the strength of the acid sites and increased the concentration of the acid sites. The morphology of the nanocatalyst was spherical including the high crystallinity, high surface area, and mesoporous structure. The 25% MoO3/B-ZSM-5 nanocatalyst showed the best performance in the esterification of FFA. The optimum operating conditions were 6 h reaction time, temperature of 160 °C, 3%wt catalyst concentration, and methanol/FFA molar ratio of 20:1, which resulted in the highest conversion of FFA (98%). The impregnated nanocatalyst had high stability and reusability through the sequence runs including only 5% conversion drop after six runs. The results confirmed the high potential of the developed nanocatalyst for industrial applications.