Co-Fe bimetallic oxides derived from Prussian blue analogs to activate peracetic acid for eliminating sulfamethazine: Contribution and identification of radical species

Peracetic acid (PAA), as a disinfectant with powerful oxidation and exceptional antimicrobial efficiency, has gained considerable attention for its application in advanced oxidation processes (AOPs). However, leaching of metal ions and low recovery efficiency limited the application of heterogeneous AOPs. Herein, we synthesized a CoFe bimetallic oxide (Co-Fe-O) derived from Prussian blue analogs to serve as an activator for PAA, efficiently eliminating sulfamethazine (SMZ) in a wide pH range (5–9). Electron paramagnetic resonance and quenching test revealed the coexistence of radical species in the system, and R-O· were the main factors of SMZ elimination. The steady-state model evaluation showed that 3.1 × 10−14 M R-O· and 2.05 × 10−14 M ·OH existed in the system. CoFe bimetallic synergies expedite the generation of radical species. Based on density functional theory, the aniline ring and heterocyclic ring of SMZ were regarded as the susceptible sites for radical attack and electron transfer. Furthermore, the elimination pathway of SMZ was proposed by combining the results of intermediate products. Additionally, the toxicity of SMZ and intermediates as well as the reaction conditions, water matrices, stability, and oxidation capacity of Co-Fe-O/PAA were subjected to evaluation. Results indicate that the Co-Fe-O/PAA system has significant application potential in the elimination of micropollutants.