Oxidative desulfurization of dibenzothiophene in model fuel using spray impregnated-biogenic silica-supported molybdenum oxide catalyst

The growing dependence on fossil fuels contributes to environmental degradation, particularly through sulfur-based emissions from compounds such as dibenzothiophene (DBT). This study presents an eco-friendly and cost-effective catalyst synthesized from agricultural waste. Silica derived from rice husk ash, induced with NaHCO3, was impregnated with molybdenum oxide (MoO3/SiO2) using a spray impregnation technique and applied in the oxidative desulfurization (ODS) of DBT using n-hexane as a model fuel. The dispersion of molybdenum oxide improved total acidity and DBT removal efficiency. Process optimization through response surface methodology with a central composite design (RSM–CCD) identified the optimal conditions as a reaction time of 32.12 min, an O/S molar ratio of 11.79, and a catalyst dosage of 3.20 wt%, yielding 96.71 % DBT removal. The catalyst also showed good reusability, maintaining 91.98 % efficiency after five cycles. These findings highlight the potential of MoO3/SiO2 as a sustainable catalyst for cleaner industrial fuel production.