State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, CH-8600 Dübendorf, Switzerland.
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
Water Res. 2017 Aug 1;119:126-135. doi: 10.1016/j.watres.2017.04.033. Epub 2017 Apr 13.
The kinetics for the reactions of hypoiodous acid (HOI) with various phenols (phenol, 4-nitrophenol, 4-hydroxybenzoic acid), 3-oxopentanedioic acid (3-OPA) and flavone were investigated in the pH range of 6.0-11.0. The apparent second order rate constants for the reactions of HOI with phenolic compounds, 3-OPA, flavone and citric acid at pH 8.0 are 10-10 Ms, (4.0 ± 0.3) × 10 Ms, (2.5 ± 0.2) × 10 Ms and <1 Ms, respectively. The effect of buffer type and concentration was investigated with acetate, phosphate and borate. All tested buffers promote the HOI reactions with phenols. The percentage of iodine incorporation for various (hydroxyl)phenolic compounds and two NOM extracts ranges from 5% to 98%, indicating that electrophilic aromatic substitution and/or electron transfer can occur. The extent of these reactions depends on the number and relative position of the hydroxyl moieties on the phenolic compounds. Iodoform formation rates increase with increasing pH and iodoform yields increase from 9% to 67% for pH 6.0-10.0 for the HOI/3-OPA reactions. In the permanganate/HOI/3-OPA and permanganate/iodide/3-OPA system at pH < 8.0, iodoform formation is elevated compared to the HOI/3-OPA system in absence of permanganate. For pH > 8.0, in presence of permanganate, iodoform formation is significantly inhibited and iodate formation enhanced, which is due to a faster permanganate-mediated HOI disproportionation to iodate compared to the iodination process. The production of reactive iodine in real waters containing iodide in contact with permanganate may lead to the formation of iodinated organic compounds.
次碘酸（HOI）与各种酚类化合物（苯酚、4-硝基苯酚、4-羟基苯甲酸）、3-氧戊二酸（3-OPA）和黄酮的反应动力学在 pH 值 6.0-11.0 范围内进行了研究。在 pH 8.0 时，HOI 与酚类化合物、3-OPA、黄酮和柠檬酸的反应的表观二级速率常数分别为 10-10 M s-1、（4.0±0.3）×10 M s-1、（2.5±0.2）×10 M s-1 和 <1 M s-1。研究了醋酸盐、磷酸盐和硼酸盐对缓冲类型和浓度的影响。所有测试的缓冲液都促进了 HOI 与酚类的反应。各种（羟基）酚类化合物和两种 NOM 提取物的碘掺入百分比范围为 5%至 98%，表明亲电芳香取代和/或电子转移可能发生。这些反应的程度取决于酚类化合物上羟基的数量和相对位置。碘仿的形成速率随 pH 值的增加而增加，HOI/3-OPA 反应的 pH 值从 6.0 增加到 10.0 时，碘仿的产率从 9%增加到 67%。在 pH <8.0 时，高锰酸盐/HOI/3-OPA 和高锰酸盐/碘化物/3-OPA 体系中，与不存在高锰酸盐的 HOI/3-OPA 体系相比，碘仿的形成增加。在 pH >8.0 时，由于高锰酸盐介导的 HOI 歧化反应生成碘酸盐的速度比碘化反应快，因此碘仿的形成受到显著抑制，碘酸盐的生成增强。在含有碘化物的实际水中，与高锰酸盐接触可能会产生活性碘，从而形成碘化有机化合物。
