Oxidation of iodide and hypoiodous acid by non-chlorinated water treatment oxidants and formation of iodinated organic compounds: A review

Publication date: 15 April 2020Source: Chemical Engineering Journal, Volume 386Author(s): Juan Li, Jin Jiang, Su–Yan Pang, Ying Cao, Yang Zhou, Chaoting GuanAbstractIodinated organic compounds (I-OCs) have raised significant public concerns due to their high toxicity. Iodide (I−) as an inorganic source of I-OCs is ubiquitously present in raw waters. I− can be easily oxidized by water treatment oxidants/disinfectants generating reactive iodine species such as hypoiodous acid (HOI), which can further react with organic compounds generating I-OCs. The oxidation of I−/HOI by chlorinated oxidants/disinfectants (e.g., chlorine (HOCl) and monochloramine (NH2Cl)) as well as formation of I-OCs during these processes has been extensively studied and well reviewed. Hence, the present work focuses on the latest findings on the transformation of I−/HOI as well as formation of I-OCs during non-chlorinated oxidation processes including permanganate, manganese dioxide, ferrate, and peroxide-based oxidation processes. First, oxidation kinetics of I−/HOI by these non-chlorinated oxidation processes and the mechanisms involved were summarized. Reactivity and pathways of HOI reaction with different targets (i.e., phenolic compounds, carbonyl compounds, and natural organic matters (NOM)) were then discussed. Further, formation of I-OCs (e.g., iodoform, iodoacetic acid, iodoacetamides, and iodinated aromatics) during these non-chlorinated oxidation processes was elucidated. Finally, th...
Source: Chemical Engineering Journal - Category: Chemistry Source Type: research