Synthesis of carbon nitride supported amphiphilic phosphotungstic acid based ionic liquid for deep oxidative desulfurization of fuels

Abstract The wettability and the electron migration are considered as significant factors that deeply affect the catalytic oxidative desulfurization (ODS) performance. Herein, a long carbon chain modified phosphotungstic acid ionic liquid [C12mim]3PW12O40 (C12PW) is immobilized on the graphitic carbon nitride (g-C3N4) to enhance the dispersion properties both in the oil phase and H2O phase. Besides, verified by control experiments and various characterization methods, the migration of electron from g-C3N4 to C12PW and electron-rich W can accelerate the formation of superoxide radical, which further increases ODS efficiency. The optimal reaction conditions and parameters are determined by continuous orthogonal experiments, showing the superior oxidative ability of the immobilized catalyst C12PW/g-C3N4 on refractory aromatic sulfides in fuels. The after-reaction detection of the catalyst is also conducted, manifesting the dibenzothiophene in the fuels totally oxidized into dibenzothiophene sulfone, the only product after the reaction. The corresponding mechanism and kinetic model fitting are also proposed in this work, and the regeneration test manifests the good stability of immobilized catalyst C12PW/g-C3N4 in ODS.