Magnetic supported ionic liquid catalysts with tunable pore volume for enhanced deep oxidative desulfurization

Magnetic core-shell structure microspheres with tunable pore volumes were synthesized and used to immobilize a polyoxometalate-based ionic liquid for oxidative desulfurization of diesel fuel. The as-prepared catalysts were characterized by transmission electron microscopy , Fourier transform infrared spectroscopy , Raman spectroscopy , and nitrogen adsorption–desorption. The results showed that the small catalyst had a large pore volume and the large catalyst had a small pore volume, while their BET surface areas and pore sizes were almost the same. Compared with the large catalyst, the small catalyst showed better catalytic activity, probably due to the promotion of its large pore volume. Under the optimal reaction conditions, the removal of 4,6-dimethyldibenzothiophene could reach 95.4% with a residual sulfur content of 9.2 mg kg −1 . After the reaction, the catalyst could be separated by a magnetic field and recycled at least 7 times with little decrease in desulfurization efficiency.