Single-atom tungsten anchored g-C₃N₄ catalysts for efficient peracetic acid activation: Toward enhanced...

Sulfamethazine (SDZ) is a common antibiotic contaminant in aquatic environments, known for its high stability and resistance to degradation, which makes conventional water treatment methods ineffective. In this study, a tungsten-based single-atom catalyst (W-SA-g-C₃N₄) was successfully synthesized and applied in a peracetic acid (PAA) activation system for SDZ degradation. The results showed that the system could degrade over 80 % of SDZ within 60 min, with a degradation rate constant four times higher than that of pure g-C₃N₄. Structural characterizations revealed that the incorporation of tungsten improved the crystallinity, surface area, and porosity of the catalyst. Tungsten atoms were uniformly dispersed as single atoms on the g-C₃N₄ support, forming stable W-N coordination structures with pyridinic nitrogen. Radical trapping experiments indicated that CH₃C(O)O• and CH₃C(O)OO• were the dominant active species responsible for SDZ degradation, while the roles of •OH and ¹O₂ were relatively lower. Cyclic stability tests further demonstrated the excellent reusability and stability of the system, underscoring its potential for efficiently degrading SDZ and other antibiotics.