Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China; College of Environment and Ecology, Chongqing University, Chongqing 400045, China.
Key Laboratory of Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China.
Sci Total Environ. 2021 Sep 15;787:147584. doi: 10.1016/j.scitotenv.2021.147584. Epub 2021 May 12.
In this study, we determined the mechanisms and kinetics of the degradations of ibuprofen (IBP) and sulfamethoxazole (SMX), and identified the active species contributions in ferrous ion (Fe(II))/free chlorine (FC) system. Reactive chlorine species (RCS) were the major contributor to the degradations of IBP (73.0%) and SMX (59.3%), respectively, at pH 3. Due to the low reaction rates between Fe(IV) and target pollutants (k = (1.5 ± 0.03) × 10 M s and k = (4.8 ± 0.2) × 10 M s) and the low [Fe(IV)] ((5.0 ± 0.6) × 10 M), Fe(IV) was not the main contributor and only contributed 0.17% and 0.86% to the degradation of IBP and SMX, respectively, at pH 3. The degradations of pharmaceuticals were facilitated by acidic conditions. Chloride (Cl) accelerated the degradation of SMX and had a weak effect on the degradation of IBP. Natural organic matter limited the degradation of IBP and SMX. Overall, we demonstrated that multiple active oxidants (Fe(IV) and RCS) are produced by Fe(II)/FC and elucidated the mechanism of active oxidants degradation of pollutants.
在本研究中，我们确定了布洛芬（IBP）和磺胺甲恶唑（SMX）降解的机制和动力学，并确定了亚铁离子（Fe(II)）/游离氯（FC）体系中活性物质的贡献。活性氯物种（RCS）分别是 pH 3 时 IBP（73.0%）和 SMX（59.3%）降解的主要贡献者。由于 Fe(IV)与目标污染物之间的低反应速率（k = (1.5 ± 0.03) × 10 M s 和 k = (4.8 ± 0.2) × 10 M s）和低 [Fe(IV)] ((5.0 ± 0.6) × 10 M），Fe(IV)不是主要贡献者，仅分别贡献了 0.17%和 0.86%，对 pH 3 时 IBP 和 SMX 的降解作用。药物的降解受到酸性条件的促进。氯离子（Cl）促进了 SMX 的降解，对 IBP 的降解作用较弱。天然有机物限制了 IBP 和 SMX 的降解。总的来说，我们证明了 Fe(II)/FC 会产生多种活性氧化剂（Fe(IV)和 RCS），并阐明了活性氧化剂降解污染物的机制。
