Research progress of advanced oxidation technology based on persulfate activation for the treatment of sulfonamides in water

Sulfonamide drugs (SAs) are one of the most frequently detected antibiotics in water, traditional biological treatment cannot effectively degrade sulfonamides, and thus the development of technology for efficient degradation of SAs has practical significance. In recent years, the advanced oxidation processes that generate sulfate radicals (\mathrmSO_4^-\cdot ) by activating persulfate (PS) have received widespread attention. Various methods for the activation of PS were focused on, including thermal, ultraviolet light, metal ion and metal oxides, carbon materials and MOFs activation and so on; and their possible activation mechanisms, advantages and disadvantages were summarized. The application of advanced oxidation processes based on persulfate activation (PS-AOPs) in the degradation of sulfonamides was reviewed and the mechanism of degradation of SAs by PS-AOPs was summarized. The results showed that the activation mechanism of PS was to break O—O bond in the molecular structure, which led to the decomposition of PS to form \mathrmSO_4^-\cdot or other active substances. The efficiency of PS-AOPs in degrading SAs was determined by the activation method. The degradation pathways of SAs were divided into free radical and non-free radical pathways, in which the free radical pathways mainly included partial oxidation of aniline, cleavage of sulfonamide groups and adjacent sites (\mathrmC—NH—\mathrmSO_2—\mathrmC ), and the non-free radical pathways included electron transfer, surface activation, and the role of single linear oxygen (¹O₂). Finally, it was suggested that the future research focus should be on the development of catalysts for stable and efficient activation of PS, as well as the synergistic effect of multiple treatment technologies. Meanwhile, research on the mechanism of SAs degradation and the actual wastewater containing SAs should be strengthened.