title: A comparison of iodinated trihalomethane formation from chlorine, chlorine dioxide and potassium permanganate oxidation processes.
abstract: This study compared the formation of iodinated trihalomethanes (I-THMs) from iodide-containing raw waters oxidized by chlorine, chlorine dioxide (ClO₂) and potassium permanganate (KMnO₄) at different oxidant concentrations, reaction times, pHs, initial iodide concentrations and bromide to iodide mass ratios. Among the six investigated I-THMs, iodoform was the major species formed during the oxidation using chlorine, ClO₂ and KMnO₄. When oxidant concentration increased from 0.1 to 3.0 mg/L, the formation of I-THMs increased and then decreased for chlorine and ClO₂, but kept increasing for KMnO₄. As the reaction time went by, I-THM concentration increased to a plateau within 10 h (ClO₂ within only 1 h, especially) for all the three oxidants. I-THM formation gradually increased from pH 3.0 to 9.0 and remained stable at pH values higher than 7.5 for chlorine; however, for ClO₂ and KMnO₄ the highest I-THM formation showed at pH 7.0 and 7.5, respectively. As initial iodide concentration increased from 20 to 800 μg/L, the total amount and species of I-THMs increased for the three oxidants. Iodide contributed to I-THM formation much more significantly than bromide.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze Aquatic Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China.
authors.forename: Tian-Yang
authors.initials: TY
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.forename: Chen-Yan
authors.initials: CY
authors.lastname: Hu
authors.forename: Yi-Li
authors.initials: YL
authors.lastname: Lin
authors.forename: Lin
authors.initials: L
authors.lastname: Lin
authors.forename: Tao
authors.initials: T
authors.lastname: Ye
authors.forename: Fu-Xiang
authors.initials: FX
authors.lastname: Tian
mesh_terms: D001965:Bromides / Q000737:chemistry; D002713:Chlorine / Q000737:chemistry*; D017606:Chlorine Compounds / Q000737:chemistry*; D004203:Disinfection; D006863:Hydrogen-Ion Concentration; D017613:Iodine Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D011196:Potassium Permanganate / Q000737:chemistry*; D022882:Trihalomethanes / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis; D018508:Water Purification / Q000379:methods*
chemical_list: D001965:Bromides; D017606:Chlorine Compounds; D017613:Iodine Compounds; D010087:Oxides; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical; D011196:Potassium Permanganate; D002713:Chlorine; C025109:chlorine dioxide