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 (CTAB) 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 °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%Mo/hAl–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. •Mo supported on hierarchical Alumina-Silica was synthesized, characterized, and applied for the ODS process.•Hierarchical Alumina-Silica was prepared via economical and ecofriendly silicate-1 seed-induced route.•The Box–Behnken experimental design was applied to determine optimum DBT conversion.•95% DBT was removed under the optimal operating conditions.