Synthesis of Zirconium Catalysts Supported on Activated Carbon for Catalytic Oxidative Desulfurization of Dibenzothiophene from N-Octane

The growing emphasis on controlling sulfur-containing compounds in fuel oils has driven the development of numerous desulfurization technologies. Among these, catalytic oxidative desulfurization (CODS) has garnered considerable research interest due to its exceptional capability to efficiently remove refractory sulfur compounds, particularly dibenzothiophene (DBT), under relatively mild reaction conditions. However, the widespread application of CODS has been hindered by the high cost and complex preparation processes of the catalysts. To enhance the practical potential of CODS, in this study, a novel Zr@AC catalyst was developed by a facile “solution impregnation + high-temperature calcination” strategy, where zirconium species were effectively supported on activated carbon. Experimental results demonstrated that under optimized conditions of 0.1 g catalyst dosage, 2.0 O/S ratio, reaction temperature 100 °C and reaction time 50 min, the Zr@AC-mediated CODS system achieved a remarkable desulfurization efficiency of 97.24% for DBT removal. The removal efficiency of DBT increased by 9.0% compared with non-catalytic systems. The characterization techniques revealed that the Zr@AC catalyst possesses a hierarchically rough surface morphology, high specific surface area, abundant active sites, and distinctive Zr-O functional groups. Kinetic analysis indicated that the oxidation process follows second-order reaction kinetics. Furthermore, the catalyst maintained over 95% desulfurization efficiency after five consecutive regeneration cycles, confirming that the prepared catalyst has the exceptional recyclability and operational stability.