Application of peroxymonosulfate and its activation methods for degradation of environmental organic pollutants: Review

Abstract

The degradation of refractory organic compounds to harmless matters is one of the major concerns of environmentalists. Advanced oxidation processes (AOPs) are promising technologies producing the hydroxyl and sulfate radicals for pollutant degradation. Recently, much attention has been paid to producing sulfate radicals through activation of peroxymonosulfate (PMS). Nowadays, the use of PMS has acquired popularity thanks to its high reactivity and also to its high potential in generating sulfate radical. Actually it is becoming an alternative for hydrogen peroxide and persulfate. PMS is an unsymmetrical oxidant which can be activated to produce both hydroxyl and sulfate radicals. Various methods of PMS activation have been reported in literature including transition metals (homogenous and heterogeneous), ultraviolet, ultrasound, conduction electron, carbon catalysts and so on. PMS activation has been broadly applied for a wide range of pollutants mostly in aqueous solution. A literature review is carried out on environmental application of PMS in degradation of contaminants to clarify the performance of PMS. This review in detail describes the PMS usage in remediation of environmental pollutants with focus on the different methods of activation and the effect of main operational parameters on PMS-based processes. Moreover, the identification of contribution of each radical is discussed based on quenching experiments and electron spin resonance method. Finally, an overview on applying PMS in real wastewater and other matrixes (air, soil and sludge) is conducted and some recommendations are proposed for future studies.