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Coagulation of Iodide-Containing Resorcinol Solution or Natural Waters with Ferric Chloride Can Produce Iodinated Coagulation Byproducts
journal contribution
posted on 2019-10-08, 21:16 authored by Shunke Ding, Yang Deng, Hongwei Li, Chao Fang, Naiyun Gao, Wenhai ChuIodinated disinfection byproducts
(I-DBPs) are of particular concern
in drinking water due to the more cytotoxic and genotoxic properties
than their chlorinated and brominated analogs. Formation of I-DBP
primarily results from the oxidation of iodide-containing waters with
various oxidants and the chlor(am)ination of iodinated organic compounds
in drinking water. This study first reports that ferric chloride (FeCl3) can lead to the formation of iodinated coagulation byproducts
(I-CBPs) from iodide-containing resorcinol solution or natural waters.
The unwanted I-CBP formation involved the oxidation of iodide by ferric
ions to generate various reactive iodine species, which further oxidize
organic compounds. Although the oxidation rate of iodide by FeCl3 was several orders of magnitude slower than that by chlorine
or chloramine, most of the converted iodide under the ferric/iodide
system was transformed into iodine and iodinated organic compounds
rather than iodate. Formation of four aliphatic I-CBPs was observed,
and four aromatic I-CBPs were identified by gas chromatography mass-spectrometry
and theoretical calculation. Coagulation of iodide-containing waters
with FeCl3 also produced I-CBPs ranging from 12.5 ±
0.8 to 32.5 ± 0.2 μg/L as I. These findings call for careful
consideration of the formation of I-CBPs from coagulation of iodide-containing
waters with ferric salts.