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Sulfamethoxazole (SMX) is highly persistent and difficult to remove, making it urgent to find an efficient method for alleviating the enormous environmental pressure of SMX. In this study, sulfide-modified nanoscale zero-valent iron on carbon nanotubes ( [email protected] ) was prepared to activate peroxydisulfate (PDS) for the degradation of SMX. The results showed that SMX was completely removed within 40 min (kobs=0.1058 min−1) in the [email protected] /PDS system. By analyzing quenching experiments and electron paramagnetic resonance (EPR), singlet oxygen (1O2) was the main active species of the [email protected] /PDS system. 1O2 might be mediated by the abundant carbonyl groups (C O) on carbon nanotubes through spectroscopic analyses. In addition, sulfur doping transitioned the activation pathway to a nonradical pathway. Spectroscopic analyses and electrochemical experiments confirmed that the formation of CNTs-PDS complexes and S-nZVI could promote electron transfer on the catalyst surface. Furthermore, the main degradation intermediates of SMX were identified, and five possible transformation pathways were proposed. The [email protected] /PDS system possessed advantages including high anti-interference (Cl-, NO3-, HA), a strong applicability, recyclability and a low PDS consumption, offering new insight into the degradation of antibiotic wastewater.
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