Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China.
Nanjing Institute of Environmental Science, Ministry of Environmental Protection of PRC, Nanjing, 210042, China.
Chemosphere. 2017 Aug;181:400-408. doi: 10.1016/j.chemosphere.2017.04.076. Epub 2017 Apr 19.
Formation of halogenated disinfection by-products (DBPs) in sulfate radical-based advanced oxidation processes (SR-AOPs) have attracted considerable concerns recently. Previous studies have focused on the formation of chlorinated and brominated DBPs. This research examined the transformation of I in heat activated PS oxidation process. Phenol was employed as a model compound to mimic the reactivity of dissolved natural organic matter (NOM) toward halogenation. It was found that I was transformed to free iodine which attacked phenol subsequently leading to iodinated DBPs such as iodoform and iodoacetic acids. Iodophenols were detected as the intermediates during the formation of the iodoform and triiodoacetic acid (TIAA). However, diiodoacetic acid (DIAA) was formed almost concomitantly with iodophenols. In addition, the yield of DIAA was significantly higher than that of TIAA, which is distinct from conventional halogenation process. Both the facts suggest that different pathway might be involved during DIAA formation in SR-AOPs. Temperature and persulfate dose were the key factors governing the transformation process. The iodinated by-products can be further degraded by excessive SO and transformed to iodate. This study elucidated the transformation pathway of I in SR-AOPs, which should be taken into consideration when persulfate was applied in environmental matrices containing iodine.
近年来，基于硫酸根自由基的高级氧化工艺（SR-AOPs）中卤代消毒副产物（DBPs）的形成引起了人们的广泛关注。先前的研究主要集中在氯化和溴化 DBPs 的形成上。本研究考察了 I 在热活化过硫酸盐氧化过程中的转化。酚被用作模型化合物，以模拟溶解态天然有机物（NOM）对卤化的反应性。结果表明，I 被转化为游离碘，随后攻击酚，导致形成碘代 DBPs，如碘仿和碘乙酸。在碘仿和三碘乙酸（TIAA）的形成过程中，检测到了碘酚作为中间体。然而，二碘乙酸（DIAA）几乎与碘酚同时形成。此外，DIAA 的产率明显高于 TIAA，这与传统的卤化过程明显不同。这两个事实表明，在 SR-AOPs 中形成 DIAA 时可能涉及不同的途径。温度和过硫酸盐剂量是控制转化过程的关键因素。过量的 SO 可以进一步降解碘代副产物，并将其转化为碘酸盐。本研究阐明了 I 在 SR-AOPs 中的转化途径，当过硫酸盐应用于含有碘的环境基质中时，应考虑这一点。
