Boosting H₂O₂ Activation for the Efficient Degradation of Dimethyl Sulfoxide-Containing Wastewater over Supported Niobia Catalysts

Abstract

Dimethyl sulfoxide (DMSO) is a widely used solvent in many industries. The biodegradation of DMSO is difficult, resulting in large amounts volatile and noxious compounds emitted into the atmosphere, including dimethylsulfide, methyl mercaptan, and H2S. Therefore, it is necessary to deal with DMSO-containing wastewater using chemical methods. Here, supported niobia catalysts were prepared and characterized, and their catalytic performances was evaluated by the oxidative degradation of DMSO via H2O2 activation. The product of DMSO oxidation is dimethylsulfone which is a biodegradable and environmentally benign compound. The most active catalyst, 20%Nb2O5/SiO2, can remove 178.6 mmol/L DMSO within 2 h at 25 °C following a pseudo-first-order reaction. EPR spectroscopic studies and scavenging experiments confirms that O2 •– and 1O2 are the active species for DMSO degradation. Although the catalytic activity of Nb2O5/SiO2 drops significantly after use, its reusability improved conspicuously after calcination, and the catalyst can be reused for 5 times with an 82.2% DMSO conversion.