Achieving highly efficient oxidative desulfurization of residue oil with a Mo supported Al2O3 catalyst under ozone conditions

Abstract

Oxidative desulfurization is a green, efficient, and cost-effective technology for sulfur removal. In this study, a Mo/Al₂O₃ catalyst was synthesized via a simple impregnation method and applied in the oxidative desulfurization (ODS) of residual oil using ozone as the oxidant. A sulfur removal efficiency of 67.51% was achieved for residual oil using this catalytic system. Following a phased strategy, the catalytic system was first evaluated using simulated oil, achieving a dibenzothiophene (DBT) desulfurization rate of 98.5%. In the subsequent phase, the catalytic system was tested using actual residual oil, where it retained considerable activity, attaining a high desulfurization efficiency of 67.51%. Using radical trapping experiments, we identified key radical species, leading to a proposed mechanism for ozone-mediated oxidation of sulfur-containing compounds. Notably, the catalytic system demonstrated robust stability, retaining over 90% of its initial activity across five consecutive reaction cycles. This synergistic approach enables highly efficient and stable desulfurization, while demonstrating strong practical potential for industrial implementation in heavy oil upgrading.