Oxidative desulfurization of model and real oil samples using Mo supported on hierarchical alumina-silica: Process optimization by Box-Behnken experimental design

The catalytic performance of Mo supported on hierarchical alumina-silica (Si/Al = 15) with Mo loadings of 3, 6 and 15 wt% was investigated for the oxidative desulfurization (ODS) of model and real oil samples. Hierarchical alumina-silica (hAl-Si) was synthesized by economical and ecofriendly silicate-1 seed-induced route using cetyltrimethylammonium bromide ((TAB) as mesoporogen. The effect of CTAB on the structure of catalyst was studied by characterization techniques. The results revealed that 6%Mo/hAl-Si had the highest sulfur removal compared to the other catalyst loadings. The effect of operating parameters was evaluated using Box-Behnken experimental design. The optimal desulfurization conditions with the 6%Mo/hAl-Si catalyst were determined at oxidation temperature of 67 degrees C, oxidation time of 42 min, H2O2/S molar ratio of 8 and catalyst dosage of 0.008 g.ml(-1) for achieving a conversion of 95%. Under optimal conditions, different sulfur-containing compounds with initial concentration of 1000 ppm, Dibenzothiophene (DBT), Benzothiophene (BT) and Thiophen (Th), showed the catalytic oxidation reactivity in the order of DBT> BT >Th. According to the regeneration experiments, the 6%MolhAl-Si catalyst was reused 4 times with a little reduction in the performance. Also, the total sulfur content of gasoline and diesel after ODS process reached 156.6 and 4592.2 ppm, respectively. (C) 2019 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.