Preparation of NiWO₄/g-C₃N₄ and its ultra-deep desulfurization properties in ionic liquid

The NiWO₄ nanoparticles were synthesized by hydrothermal method. The supported catalysts NiWO₄/g-C₃N₄ were prepared by a simple mixing-calcination method. XRD, FT-IR, EDS, SEM, BET and XPS were used to characterize the morphology and structure of NiWO₄/g-C₃N₄. The prepared NiWO₄/g-C₃N₄ was used as catalyst, hydrogen peroxide as oxidant, 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid (BMIMBF₄) as extractant for oxidative desulfurization. The effects of catalyst loading, the amount of hydrogen peroxide, ionic liquid and catalyst, reaction temperature, reaction time, and different sulfur compounds on desulfurization efficiency were studied. The desulfurization rate can reach 97.35% at the optimum reaction conditions:5 mL of model oil, 0.2 mL of hydrogen peroxide, 1.0 mL of BMIM BF₄, 0.03 g of NiWO₄/g-C₃N₄, 80 ℃ of reaction temperature and 140 min of reaction time. The results showed that NiWO₄/g-C₃N₄ had good catalytic stability, and the catalytic activity was not significantly reduced after 5 repeated reactions.