Abstract: Heterogeneous activation of peroxymonosulfate (PMS) becomes an important technology for degradation of organic compounds in aqueous solutions by generating sulfate radicals and hydroxyl radicals. In this study, three types of MnO2 catalysts were synthesized: two 1D manganese dioxides，nanorods and nanowires, and one α-MnO2 without a specific appearance. The catalytic performance of three MnO2 catalysts for Rh B degradation in aqueous solutions through activated PMS was compared. The results indicated that the nanowire MnO2 has the highest activity. By investigating the influence of different factors on the catalytic activity of nanowire MnO2, the best conditions for the degradation of Rh B in water are as follows: 35℃，pH=8, Rh B concentration of 10μg/g, PMS 0.5 g/L and nanowire MnO2 0.3 g/L. By the experiments of eliminating radicals, the mechanism for Rh B degradation in aqueous solution through activating PMS was studied, indicating that the sulfate radical from PMS activation plays an important role in degradation of organic compounds. The activation of PMS, the generation of sulfate radical and the process of Rh B degradation are illustrated in detail.

Key words: Metal Oxide, peroxymonosulfate, sulfate radical, catalysis, degradation