Boosting hydrogen peroxide activation for the high-efficient removal of volatile dimethylsulfoxide over niobium-based catalysts.

[Display omitted] • Amorphous niobium oxyhydroxide and crystalline niobium oxide catalysts were synthesized. • The contribution of surface-adsorbed hydroperoxo groups, O 2 •− and 1O 2 was identified. • DMSO is degraded to biodegradable and environmentally benign dimethyl sulfone. • NbO 2 OH efficiently removed 179 mmol/L DMSO form wastewater within about 80 min at 25 °C. Dimethyl sulfoxide (DMSO) is an important solvent in numerous industries. The biodegrading process of DMSO is slow and produces toxic volatile compounds including CH 3 SCH 3 , CH 3 SH, and H 2 S. Hence, it is important to develop chemical methods for treating DMSO-containing wastewater. In the present work, niobium oxyhydroxide and niobium oxide were synthesized and used to activate hydrogen peroxide for the degradation of DMSO to DMSO 2. The niobium oxyhydroxide catalyst exhibited much better catalytic activity for DMSO oxidation than niobium oxide. EPR spectra and radical scavenging experiments confirmed that O 2 •− and 1O 2 are the main active species for the oxidation of DMSO. FTIR analysis and DFT calculation confirmed that the surface hydroxyl of niobium oxyhydroxide can be substituted by hydroperoxo group of H 2 O 2 to form Nb−OOH group, which can directly oxidize DMSO or indirectly oxidize DMSO via O 2 •− and 1O 2. However, H 2 O 2 cannot form hydroperoxo group on the surface of niobium oxide, which might trigger the lower activity of niobium oxide catalysts than the niobium oxyhydroxide catalyst. The niobium oxyhydroxide catalyst exhibited good reusability and was promising for the treatment of DMSO-containing wastewater. [ABSTRACT FROM AUTHOR]