Revisiting the multipath elimination of contaminants by carbonyl-containing manganese-carbon composites in the peroxymonosulfate system: A new way of constructing C-Mn-PMS complexes to distinguish the stages of active species production

The use of value-added effects of composite catalysts to enhance the practical application of peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) has been one of the hot topics in the field of environmental remediation. However, the complex structure of the composite catalyst/PMS systems has hindered the exploration of the origin and generation stages of active species. To clarify the relationship between active sites and active species, Mn carbon-based composite/PMS systems with structured active sites were constructed to achieve an effective strategy for organic conversion. This paper investigates the correlation between C = O-Mn and reactive species generation by developing Mn carbon composites with structured active sites (C = O) to activate PMS for the degradation of TCH. Additionally, a pre-oxidation experiment was proposed to divide the whole catalytic degradation process into two stages: oxidation and degradation. The results show that the C = O–Mn–PMS composite intermediate can still effectively degrade Tetracycline after being separated from the solution. The study also revealed the structure–function relationship of different active sites in the C = O-Mn catalyst was revealed by density functional theory (DFT) calculations. The Mn-O, Mn-O-Mn and C = O structures achieved efficient utilization of PMS and rapid degradation of TCH through the adsorption of PMS and single electron transfer generation SO4−, OH, O2−, 1O2. This paper provides new ideas for the reaction mechanism and rational design of catalysts based on the Mn-carbon composite/PMS system.