Insights into the potential applications of permanganate/peroxymonosulfate systems: enhancement amorphous MnO, effects of water matrices, and optimization using response surface methodology.

In this study, we developed a novel self-catalytic oxidation system involving peroxymonosulfate (PMS) and permanganate (KMnO), named as CUPP, to efficiently mineralize sulfamethoxazole (SMX) in groundwater. It was found that amorphous MnO derived from the reduction of KMnO can directly adsorb HSO, a complex hydroxyl group, mediate the internal disproportionation reaction of HSO with the manganese complex, and effectively activate PMS, thereby promoting the oxidation of SMX and its degradation intermediates through sulfonate radiation. Furthermore, by using electron spin resonance (EPR), HPLC/MS full scan, and response surface methodology, the coexistence of HO˙, SO˙, O˙, O, and active chlorine (Cl, HOCl) in the CUPP system was confirmed. A total of 24 intermediate products were detected, and four possible degradation pathways were identified for SMX. In addition, it was found that the CUPP system has a strong impact resistance to pH variations, groundwater anions, and natural organic matter stress. Undoubtedly, the CUPP system presents an innovative approach for the degradation of various emerging organic pollutants in groundwater.