Liu Yiqing, Xu Linghan, Li Xin, Wang Shixiang
School of Environmental Science and Engineering, Southwest Jiaotong University, Chengdu, People's Republic of China.
Environ Technol. 2025 Jun;46(14):2670-2680. doi: 10.1080/09593330.2024.2442779. Epub 2024 Dec 31.
Ascorbic acid (AA) was used as a reducing agent to improve the Fe(III)-activated peracetic acid (PAA) system for the removal of sulfamethoxazole (SMX) in this work. The efficiency, influencing factors and mechanism of SMX elimination in the AA/Fe(III)/PAA process were studied. The results exhibited that AA facilitated the reduction of Fe(III) to Fe(II) and subsequently improved the activation of PAA and HO. Various radicals, including organic radicals (e.g. CHC(O)O• and CHC(O)OO•) and hydroxyl radical (HO•), were rapidly formed from the activated PAA and HO, resulting in SMX removal. Increasing dosages of PAA and Fe(III) contributed to enhanced SMX degradation, while excessive PAA and Fe(III) did not further promote SMX degradation. Due to the radicals' quenching effect, excess AA hindered SMX elimination in the AA/Fe(III)/PAA process. The presence of and Cl inhibited SMX removal in this system, whereas , and natural organic matter had little impact on SMX degradation. The transformation pathways of SMX in the AA/Fe(III)/PAA system included hydroxylation, bond cleavage and amino oxidation. This research provides a strategy to enhance the Fe(III)-activated PAA system for the elimination of refractory organic pollutants.
在本研究中，抗坏血酸（AA）被用作还原剂来改进铁（III）活化过氧乙酸（PAA）体系以去除磺胺甲恶唑（SMX）。研究了AA/铁（III）/PAA体系中SMX去除的效率、影响因素及机制。结果表明，AA促进了铁（III）还原为铁（II），进而提高了PAA和羟基自由基（·OH）的活化。活化的PAA和·OH迅速生成各种自由基，包括有机自由基（如CH₃C(O)O·和CH₃C(O)OO·）和羟基自由基（·OH），从而实现SMX的去除。增加PAA和铁（III）的用量有助于提高SMX的降解效果，而过量的PAA和铁（III）并不会进一步促进SMX的降解。由于自由基的猝灭作用，过量的AA在AA/铁（III）/PAA体系中阻碍了SMX的去除。NO₃⁻和Cl⁻的存在抑制了该体系中SMX的去除，而SO₄²⁻、HCO₃⁻和天然有机物对SMX的降解影响较小。SMX在AA/铁（III）/PAA体系中的转化途径包括羟基化、键断裂和氨基氧化。本研究为增强铁（III）活化PAA体系去除难降解有机污染物提供了一种策略。
