Rapid oxidation of iodide and hypoiodous acid with ferrate and no formation of iodoform and monoiodoacetic acid in the ferrate/I-/HA system
Rapid oxidation of iodide and hypoiodous acid with ferrate and no formation of iodoform and monoiodoacetic acid in the ferrate/I-/HA system
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DOI：
10.1016/j.watres.2018.07.061
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发表时间：
2018-11-01
期刊：
影响因子：
12.8
通讯作者：
Ma, Jun
中科院分区：
文献类型：
--
作者：
Wang, Xianshi;Liu, Yulei;Ma, Jun
含碘水化学氧化过程中会产生有毒恶臭的碘化消毒副产物(I-DBPs)。控制I-DBPs的一个关键步骤是将碘物种转化为稳定、无害的碘酸盐(IO3-)，同时抑制高活性次碘酸(HOI)的积累。本文研究了高铁酸盐对I-和HOI的氧化作用，并用停流分光光度计用2，2‘-azino-bis(3-ethylbenzothiazoline-6-sulfonate)(ABTS)显色法测定了HOI的生成轮廓。在pH为5.3~10.3时，高铁酸盐与HOI反应的二级速率常数(k(App))从1.6×10~(-5)M(-1)S(-1)降至8.3×10~(-2)M(-1)S(-1)，分别是高铁酸盐在pH 6.0、7.0和8.0时的7.5、7.2和13.8倍。与臭氧、次氯酸、氯胺和高锰酸钾等其他氧化剂相比，高铁酸盐能迅速氧化I-氧化过程中形成的HOI。对于含碘水的高铁酸盐氧化，HOI在pH 5.0~9.0范围内被迅速氧化为IO3-。磷酸盐缓冲液促进高铁酸氧化HOI，而促进I-的氧化。当腐植酸(HA)浓度为5mgC/L时，高铁酸盐(10~80mM)氧化碘化物(20mM)时，未观察到碘仿和一碘乙酸的生成。这些结果表明，高铁酸盐氧化是控制含碘水处理中I-DBPs的一种有效方法。(C)爱思唯尔有限公司出版的2018年。
Toxic and odorous iodinated disinfection byproducts (I-DBPs) could form in the chemical oxidation of iodine-containing water. A critical step for controlling the hazardous I-DBPs is to convert the iodine species into stable and harmless iodate (IO3-) while inhibiting the accumulation of highly reactive hypoiodous acid (HOI). Herein, the oxidation of I- and HOI with ferrate was investigated, and the formation profile of HOI was determined based on 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) coloring method through a stopped-flow spectrophotometer. The second-order rate constants (k(app)) of ferrate with HOI decreased from 1.6 x 10(5) M(-1)s(-1) to 8.3 x 10(2) M(-1)s(-1) as the solution pH varied from 5.3 to 10.3, which were 7.5, 7.2 and 13.8 times higher than that of ferrate with I- at pH 6.0, 7.0 and 8.0, respectively. Compared with other oxidants such as ozone, hypochlorous acid, chloramine and potassium permanganate, ferrate would swiftly oxidize HOI formed in the I- oxidation process. For the ferrate oxidation of I-containing water, HOI was swiftly oxidized to IO3- from pH 5.0 to 9.0. Phosphate buffer promoted the oxidation of I- while inhibited the oxidation of HOI with ferrate. When 5 mgC/L of humic acids (HA) existed in the solution, no formation of iodoform and monoiodoacetic acid (MIAA) was observed in the oxidation of iodide (20 mu M) with ferrate (from 10 mu M to 80 mu M). These results suggested that ferrate oxidation could be an effective method for the control of I-DBPs in iodine-containing water treatment. (C) 2018 Published by Elsevier Ltd.