Preparation and Its Catalytic Oxidative Desulfurization Properties of Bismuth Tungstate

Catalytic oxidative desulfurization method can deeply and efficiently remove dibenzothiophene (DBT) sulfur-containing compounds in fuel oil due to its mild reaction conditions. It is a non-hydrodesulfurization method with potential application value. The samples of bismuth tungstate (Bi2WO6) were prepared using sodium tungstate and bismuth nitrate pentahydrate as raw materials by direct precipitation method and hydrothermal method. Their structure, composition, surface morphology and specific surface area were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), and N2 isotherm adsorption-desorption method. Taking DBT, benzothiophene (BT), 4-methyldiphenylpropythipphere (4-MDBT), and 4,6-dimethyldiphenylpropythipphere (4,6-DMDBT) as representative sulfur compounds, the sulfur-containing simulated oil was made up by using n-decane as solvent and n-tetradecane as internal standard. A catalytic oxidation desulfurization system was constructed through the prepared Bi2WO6 as catalyst, hydrogen peroxide (H2O2) as oxidant and acetonitrile (CH3CN) as extractant, and the desulfurization performance was systematically investigated. The results indicated that Bi2WO6 prepared by hydrothermal method has excellent desulfurization performance. The desulfurization rate of BWO2 for simulated oil containing DBT reached 99.7% in 75 min at the reaction temperature of 60 ℃. The kinetic fitting results indicated that the catalytic oxidation desulfurization of DBT simulated oil by BWO2 accords with the first-order kinetic equation, and its activation energy is 55.45 kJ/mol. © 2023 Science Press. All rights reserved.