Degradation of Rhodamine B by the α-MnO2/Peroxymonosulfate System

Abstract

Rhodamine B (RhB) is one of synthetic dyes with good stability. Treatment of wastewater containing synthetic dyes has attracted much attention. Heterogeneous activation of peroxymonosulfate (PMS) has been found to be a promising wastewater treatment technology through the activation with metal oxides for the generation of sulfate radicals. In this study, α-MnO2 was prepared by a simple hydrothermal method and used as the catalyst to activate PMS. The degradation of RhB was studied by the α-MnO2/PMS system. It was found that the prepared α-MnO2 exhibited high catalytic activity on the activation of PMS for the degradation of RhB. The degradation of RhB could be well described by the first-order kinetic model. Influences of PMS concentration and α-MnO2 dose on the degradation of RhB were examined. The chemical oxygen demand (COD) was determined to evaluate the mineralization capability of the α-MnO2/PMS system. The stability of α-MnO2 was also investigated through reusability experiments. Quenching tests of radicals were applied to differentiate the contribution of major reactive species for the degradation of RhB by the α-MnO2/PMS system.