A novel core–shell nanostructured catalyst was synthesized by supporting Keplerate nanoball iso-polyoxomolybdate {Mo132} on ionic liquid-functionalized magnetic silica nanoparticles (MSN/IL-{Mo132}), and characterized by several techniques including FT-IR, XRD, TEM, VSM, and EDX analysis. The performance of the catalyst was investigated in deep oxidative desulfurization of a model fuel (MF) containing dibenzothiophene (DBT). The effects of three operational parameters including reaction temperature, O/S molar ratio, and catalyst dosage were evaluated by optimal design of experiments based on response surface methodology (RSM). Moreover, the optimum conditions were obtained at temperature of 62.5 °C, catalyst dosage of 0.0065 g cat/g MF, and O/S molar ratio of 20.5, to achieve a high sulfur removal of 99.97% within 30 min of reaction time. Kinetic study of the process was also performed to better understand the catalytic oxidative desulfurization of DBT. The catalyst was simply separated from the reaction medium by using an external magnetic field and reused four times in the process without significant decrease in its activity. By using GC-MS analysis, DBT sulfone was detected to be the only product in oxidation of DBT over the catalyst. This research describes a new, efficient and magnetically recoverable catalyst which is highly effective in oxidative removal of refractory sulfur-containing compounds such as DBT from fossil fuels.

Keywords