Catechin-enhanced sulfamethoxazole degradation in Fe(II) activated peracetic acid process: Efficiency, mechanism and affecting factors

Peracetic acid (PAA), a commonly used environmentally friendly disinfectant, has recently gained attention on its potential for degrading organic pollutants in water due to its high oxidation potential. A potential approach for enhancing the Fe(II)/PAA process was proposed in this study. The effect of catechin (CAT), a polyphenolic antioxidant, on Fe(II)/PAA system for the degradation of sulfamethoxazole (SMX) in water was investigated. The results showed that CAT significantly enhanced the degradation efficiency of Fe(II)/PAA against SMX. The SMX degradation rate improved from 39.2 % to 88.2 % in 60 min in the presence of CAT. CAT might serve as an effective reducing agent to quantitatively reduce Fe(III) to Fe(II) with a molar ratio of about 1:2.4 between CAT and Fe(III). Reactive species were fully identified. Hydroxyl radicals, organic radicals and FeIVO2+ might involve in the degradation of SMX. Affecting factors including reagent dose, pH and water matrices were investigated. Three possible degradation pathways of SMX were proposed based on the identified reaction products, underscoring its potential applicability in water treatment.