State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, P. R. China.
Water Environ Res. 2022;94(9):e10788. doi: 10.1002/wer.10788.
During oxidative treatment of iodide (I )-containing waters, I is easy to be oxidized into hypoiodous acid (HOI) by various oxidants and the further reaction of HOI with organic compounds can lead to the formation of iodinated disinfection by-products (I-DBPs). Oxidation of HOI to iodate (IO ) or reduction of HOI to I has been proposed to reduce the formation of I-DBPs. Because the reaction of HOI with sulfite proceeds rapidly, this study examined the fate of iodine and the formation of I-DBPs in Mn(VII)/sulfite process. Results showed that I was oxidized to HOI but the further formation of IO was suppressed due to the fast reduction of HOI to I by sulfite. The reactions of HOI with SO and IO with SO are the major pathways with species-specific second-order rate constants determined to be 1.12 × 10 M s and 9.43 × 10 M s , respectively. The rapid reaction of HOI with sulfite plays an essential role in minimizing the formation of iodinated products in HOI- and phenol-containing solutions. The toxic risk analysis showed that the toxicity of the generated DBPs from Mn(VII)/sulfite pre-oxidation followed by chlorination only changed slightly. PRACTITIONER POINTS: The decay of I was negligible in Mn(VII)/sulfite process. The rapid reaction of HOI with SO resulted in the negligible generation of IO . Mn(VII)/sulfite process exerted slight influence on the formation of I-DBPs. Mn(VII)/sulfite process is promising for the pretreatment of I -containing water.
在含碘（I）水的氧化处理过程中，I 很容易被各种氧化剂氧化成次碘酸（HOI），HOI 与有机化合物的进一步反应会导致形成碘代消毒副产物（I-DBPs）。氧化 HOI 为碘酸盐（IO ）或还原 HOI 为 I 已被提议用于减少 I-DBPs 的形成。由于 HOI 与亚硫酸盐的反应速度很快，因此本研究考察了 Mn(VII)/亚硫酸盐过程中碘的归宿和 I-DBPs 的形成。结果表明，I 被氧化为 HOI，但由于亚硫酸盐快速将 HOI 还原为 I，进一步形成 IO 的过程受到抑制。HOI 与 SO 和 IO 与 SO 的反应是主要途径，确定的物种特异性二级速率常数分别为 1.12×10 M s 和 9.43×10 M s 。HOI 与亚硫酸盐的快速反应在最小化 HOI 和酚类化合物溶液中碘代产物的形成方面起着至关重要的作用。毒性风险分析表明，Mn(VII)/亚硫酸盐预氧化后氯化生成的 DBPs 的毒性仅略有变化。
在 Mn(VII)/亚硫酸盐过程中，I 的衰减可以忽略不计。
HOI 与 SO 的快速反应导致 IO 的生成可忽略不计。
Mn(VII)/亚硫酸盐过程对 I-DBPs 的形成影响不大。
Mn(VII)/亚硫酸盐过程有望用于预处理含 I 水。
