State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
Qingdao Engineering Research Center for Rural Environment, College of Resource, and Environment, Qingdao Agricultural University, Qingdao 266109, China.
Water Res. 2021 Apr 15;194:116951. doi: 10.1016/j.watres.2021.116951. Epub 2021 Feb 18.
Highly toxic iodinated phenolic by-products were frequently detected in the oxidative treatment and disinfection of iodine-containing water. Herein, it was found that three model iodinated phenolic disinfection byproducts (DBPs), 2-iodophenol, 4-iodophenol and 2,4,6-triiodophenol, were reactive with HOCl, and the reaction rate constants (at pH 7.0 and 25℃) were 1.86 ×10, 1.62 ×10 and 7.5 ×10 Ms, respectively. When HOCl was in excess (HOCl/iodophenol = 40/1, [iodophenol] = 20 μM), acute toxicity of water sample containing iodophenols could be largely eliminated (> 85%), with the conversion of iodophenols into stable and non-toxic iodate (IO) and iodinated and chlorinated aliphatic DBPs. Besides IO, seven kinds of aromatic intermediate products including iodophenols, chloroiodophenols, iodoquinones, chloroiodoquinones, chloroquinones, chlorophenols, and coupling products were detected. C-I bond of iodophenols was cleaved in the reaction and the resulted aromatic products were further transformed into chlorinated aliphatic DBPs [trichloromethane (TCM), trichloroacetic acid (TCAA), dichloroacetic acid (DCAA), and chloral hydrate (CH)] (mg/L level) and iodinated trihalomethanes (μg/L level). HOCl was effective for converting iodophenols into IO and less toxic chlorinated aliphatic DBPs. Considering that chlorine was widely used as disinfectant, transformation and toxicity alteration of emerging DBPs during chlorination/booster chlorination warrant further investigations.
高毒性的含碘酚类副产物经常在含碘水的氧化处理和消毒过程中被检测到。在此，发现三种模型碘代酚类消毒副产物（DBPs），2-碘苯酚、4-碘苯酚和 2,4,6-三碘苯酚，与 HOCl 反应，反应速率常数（在 pH 7.0 和 25℃下）分别为 1.86×10、1.62×10 和 7.5×10 Ms。当 HOCl 过量（HOCl/碘苯酚=40/1，[碘苯酚]=20 μM）时，含有碘苯酚的水样的急性毒性可以被大大消除（>85%），将碘苯酚转化为稳定且无毒的碘酸盐（IO）和含碘氯化脂肪族 DBPs。除了 IO，还检测到七种芳香族中间产物，包括碘苯酚、氯碘苯酚、碘醌、氯碘醌、氯醌、氯苯酚和偶联产物。碘苯酚中的 C-I 键在反应中被切断，生成的芳香产物进一步转化为氯化脂肪族 DBPs[三氯甲烷（TCM）、三氯乙酸（TCAA）、二氯乙酸（DCAA）和水合氯醛（CH）]（mg/L 级）和含碘三卤甲烷（μg/L 级）。HOCl 有效将碘苯酚转化为 IO 和毒性较低的氯化脂肪族 DBPs。考虑到氯广泛用作消毒剂，因此在氯化/增强氯化过程中新兴 DBPs 的转化和毒性变化值得进一步研究。
