Indirect photodegradation of sulfisoxazole: Effects of environmental factors (CDOM, pH, salinity, HCO3−, metal ions, halogen ions and NO3−)

Duan, Jiaqi; Jian, Huimin; Dou, Qiwei; Shi, Xiaoyong; Su, Rongguo

Indirect photodegradation of sulfisoxazole: Effects of environmental factors (CDOM, pH, salinity, HCO3−, metal ions, halogen ions and NO3−)

2022

Duan, Jiaqi | Jian, Huimin | Dou, Qiwei | Shi, Xiaoyong | Su, Rongguo

It's a new perspective to explore the influences of chromophoric dissolved organic matter (CDOM) components and environmental factors on the removal of sulfisoxazole (SIX) from the water matrix. Reactive intermediates (RIs) trapping experiments demonstrated that excited triplet-state CDOM (³CDOM⁎) played a dominant promoting role (54.11%) in the CDOM-mediated SIX indirect photodegradation. Additionally, terrestrial humic-like (C1, C3 and C4) and marine humic-like (C2) fluorescent components were identified by parallel factor (PARAFAC) analysis of CDOM excitation-emission matrix spectroscopy (EEMs). C1 and C4 were significantly correlated (R² > 0.91) with the SIX degradation rate owing to their higher productivity of RIs and a greater contribution to the production of ³CDOM⁎ compared to others. Salinity, pH and HCO₃⁻ were conducive to the SIX indirect photodegradation, while metal ions (Fe³⁺ and Cu²⁺), halogen ions (Cl⁻ and Br⁻) and NO₃⁻ were opposite. These findings are essential for understanding the environmental fate of SIX in coastal waters.

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