Oxidative Desulfurization of Dibenzothiophene Using M/TiO2/MWW (M = Cu, Ag, and Au) Composite
Narges Elmi Fard, Reza Fazaeli, Mohammad Yousefi, Shahrzad Abdolmohammadi
Abstract
Zeolite MWW was synthesized by microwave and hydrothermal method, and used as the support on which M/TiO2 (M = Cu, Ag, and Au) was loaded via wet impregnation method. Dibenzothiophene (DBT) removal in mild conditions was studied on various catalysts: MWW, Cu/TiO2/MWW, Ag/TiO2/MWW, and Au/TiO2/MWW. Among the synthesized composites, Au/TiO2/MWW, Ag/TiO2/MWW, and Cu/TiO2/MWW had better performance. Also, the results indicated that Au/TiO2/MWW considerably outperformed MWW. Response surface methodology (RSM) with central composite design (CCD) was used to study the effects of Au/TiO2/MWW composite loading, H2O2 volume, and temperature. Finally, the optimal conditions providing the highest conversion of sulfur (99.99%) were determined as 0.24 g Au/TiO2/MWW, 0.26 mL H2O2 and temperature of 59.4°C. Based on the results, Au/TiO2/MWW composite was shown to be an efficient catalyst for oxidation of sulfur heterocycles. The results of kinetic study indicated that pseudo first-order model has a good agreement with the experimental data. The desulfurization of gas condensate was studied under optimal conditions. The desulfurization efficiency over Au/TiO2/MWW catalyst was 89.11%.