Abstract
The current study comprises the successful synthesis of a Ni-WO3@g-C3N4 composite as an efficient and recoverable nanocatalyst for oxidative desulfurization of both model and real fuel oils. The physiochemical characterization of the synthesized composite was confirmed via Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. SEM results showed that Ni-WO3 particles were well-decorated on the g-C3N4 surface with an interesting morphology as appeared on the surface like spherical particles. The obtained findings revealed that 97% dibenzothiophene (DBT) removal can be achieved under optimized conditions (0.1 g of the catalyst, 1 mL of an oxidant, 100 mg/L DBT-based model fuel, a time duration of 180 min, and a temperature of 40 °C). Additionally, the catalytic activity for real fuel was also investigated in which 89.5 and 91.2% removal efficiencies were achieved for diesel and kerosene, respectively, as well as fuel properties following ASTM specifications. A pseudo first-order kinetic model was followed well for this reaction system, and the negative value of ΔG was due to the spontaneous process. Additionally, the desulfurization study was optimized via a response surface methodology (RSM/Box-Behnken design) for predicting optimum removal of sulfur species by drawing three-dimensional RSM surface plots. The Ni-WO3@g-C3N4 proved to be a promising catalyst for desulfurization of fuel oil by exhibiting reusability of five times with no momentous decrease in efficiency.