Deep oxidative desulfurization of dibenzothiophene using low-temperature-mediated titanium dioxide catalyst in ionic liquids

A kind of highly active TiO 2 was prepared and applied in the extractive and catalytic oxidative desulfurization (ECODS) system. The catalyst was synthesized through a simple method and characterized by X-ray powder diffraction (XRD), Raman, Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). Various of reaction conditions were investigated on the removal of dibenzothiophene (DBT), and a sulfur removal of 99.1% was obtained under 40   °C in 90   min. In addition, electron spin resonance (ESR) spectroscopy and gas chromatography–mass spectrometer (GC–MS) measurements were employed to investigate the reaction mechanism. It was proved that superoxide radical ( O 2 − ) was the active oxygen species and DBTO 2 was the only oxidation product of DBT in the ECODS system. The recycling experiments indicated that sulfur removal could still reach 95.5% after 12 times.