Oxidative desulfurization of dibenzothiophene via layered graphitic carbon nitride-coordinated transition metal as a catalyst

Abstract

In this study, graphitic carbon nitride (g-C₃N₄) has been synthesized. The cobalt-doped (CoO/g-C₃N₄) samples prepared by the impregnation method and their catalytic property were investigated on the ODS process. The structure and components of the prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption–desorption (BET), and Fourier-transform infrared (FT-IR) spectroscopy. The parameters, such as the reaction temperature, oxidant dosage, amount of catalyst, different cobalt contents loaded (5, 15, 30, 45, and 60 wt%), and reaction time, were optimized by the Taguchi method. Results demonstrated that under the optimal condition (65 °C, 0.05 ml oxidant, 0.06 g catalyst, 45% of cobalt loading, and 80 minutes), the conversion reached 86.7%. Besides, it revealed that cobalt contents loaded are the most effective parameters in the ODS process. In addition, the efficiency decreased sharply by adding cyclohexanone, which demonstrated that it has a strong negative effect on efficiency. Finally, a reaction mechanism for the catalytic oxidation of DBT in the presence of CoO/g-C₃N₄ was proposed.