Formation of iodinated trihalomethanes during UV/chloramination with iodate as the iodine source. (1st July 2016)

• Record Type: Journal Article
• Authors: Zhang, Tian-Yang; Lin, Yi-Li; Wang, An-Qi; Tian, Fu-Xiang; Xu, Bin; Xia, Sheng-Ji; Gao, Nai-Yun
• Is Part Of: Water research. Volume 98(2016)
• Page Start: 199
• Page End: 205
• Publication Date: 2016-07-01
• Subjects: Iodinated trihalomethanes (I-THMs) -- Iodate (IO3−) -- Iodine source -- UV irradiation -- Chloramination; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2016.04.012
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Iodinated trihalomethanes (I-THMs) are a group of emerging disinfection by-products with high toxicity, and iodide (I − ) as well as iodinated organic compounds are expected to be their iodine sources. Nevertheless, in this study, iodate (IO3 − ) was proven to be a new iodine source of I-THM formation during UV/chloramination. In the iodate-containing waters (without any other iodine sources), I-THM formation increased with the increase of UV dose, IO3 − and NH2 Cl concentrations. With the increase of Br − /IO3 − molar ratio, I-THM formation (especially for the brominated species) increased. Besides, NOM species could affect I-THM formation from IO3 − during UV/chloramination. Fulvic acid could promote IO3 − phototransformation to I − but humic acid impeded the production of I − during UV irradiation. Under realistic drinking water treatment conditions (DOC = 5.0 mg-C/L, IO3 − = 12.7 μg-I/L, UV dose = 50 mJ/cm 2, NH2 Cl = 5 mg-Cl2 /L), CHCl2 I was detected as 0.17 μg/L using solid-phase microextraction method, and the production rate of I-THMs from IO3 − was about 7% of that from I − . Graphical abstract: Highlights: IO3 − is a new iodine source of I-THM formation during UV/chloramination. I-THMs increased with the increase of UV dose, IO3 − and NH2 Cl concentrations. High Br − level enhanced I-THM formation from IO3 − during UV/chloramination. NOM species affect I − production and I-THM formation during UV/chloramination.