Preparation and characterization of Mg/TiO2 for visible light photooxidative-extractive deep desulfurization

Abstract

A series of Mg/TiO2 photocatalysts were prepared using aqueous wet impregnation method at different Mg loading followed by calcination at different temperatures for 1 h duration. The photocatalysts were characterized using thermal gravimetry, Fourier-transform infrared spectroscopy, x-ray diffraction, field emission scanning electron microscopy and high-resolution transmission electron microscopy. The photocatalysts were investigated for photooxidative-extractive deep desulfurization of model oil containing dibenzothiophene at room temperature and under visible light irradiation. The model oil containing 100 ppm S was photooxidized followed by extraction using imidazolium-phosphate ionic liquids at room temperature. The best performing photocatalyst was 0.25 wt. % Mg/TiO2 calcined at 400°C (0.25Mg400), in which 98.4% of dibenzothiophene (3.070 mmol DBT per g photocatalyst) was converted to dibenzothiophene sulfone. The highest extraction efficiency of 97.8% (0.01525 mmol S per mL ionic liquid) was displayed by 1,2-diethylimidazolium diethylphosphate.