Catalytic oxidation of dimethyl sulfide with ozone: Effects of promoter and physico-chemical properties of metal oxide catalysts

This study reports improved catalytic activities and stabilities for the oxidation of dimethyl sulfide (DMS), a major pollutant of pulp and paper mills. Ozone was used as an oxidant and activities of Cu, Mo, Cr and Mn oxides, and mixed metal oxides supported on γ-alumina, were tested over the temperature ranging from 100 to 200 °C. The best catalytic activity was obtained over 10 wt.% CuO-10 wt.% MoO3 supported on γ-Al2O3 with 100% DMS conversion and high selectivity (≈96%) towards complete oxidation products such as CO2 and SO2. The addition of molybdenum to the CuO/γ-Al2O3 significantly enhanced the selectivity of the reaction towards complete oxidization products indicating that MoO3 acts as a good promoter when used with CuO. Catalyst characterization by XRD, TPR and NH3-TPD analyses suggested that these promoting effects are due to the formation of Cu3Mo2O9 and CuMoO4 species on CuO-MoO3/γ-Al2O3, and also a substantially higher quantity of acid sites and a stronger acid strength in CuO-MoO3/γ-Al2O3 than CuO/γ-Al2O3 catalyst. This study also reports the optimization of reaction parameters and effects the catalyst physico-chemical properties have on the catalytic activity.

Gas phase oxidation of dimethyl sulfide (DMS) with ozone was achieved over Cu, Mo, Cr and Mn oxides, and mixed metal oxides supported on γ-alumina. The initial concentration of DMS was 500 ppmv and catalyst activities were tested over 100–200 °C. Total conversion of DMS was achieved with ozone over 10 wt% CuO-Mo supported on γ- Al2O3, and the selectivity to SO2 and COx was about 96%.Figure optionsDownload as PowerPoint slide