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Kinetic and mechanistic understanding of chlorite oxidation during chlorination: Optimization of ClO2 pre-oxidation for disinfection byproduct control.
Water Res. 2022 Jul 15; 220:118515.WR

Abstract

Chlorine dioxide (ClO2) applications to drinking water are limited by the formation of chlorite (ClO2-) which is regulated in many countries. However, when ClO2 is used as a pre-oxidant, ClO2- can be oxidized by chlorine during subsequent disinfection. In this study, a kinetic model for the reaction of chlorine with ClO2- was developed to predict the fate of ClO2- during chlorine disinfection. The reaction of ClO2- with chlorine was found to be highly pH-dependent with formation of ClO3- and ClO2 in ultrapure water. In presence of dissolved organic matter (DOM), 60-70% of the ClO2- was transformed to ClO3- during chlorination, while the in situ regenerated ClO2 was quickly consumed by reaction with DOM. The remaining 30-40% of the ClO2- first reacted to ClO2 which then formed chlorine from the DOM-ClO2 reaction. Since only part of the ClO2- was transformed to ClO3-, the sum of the molar concentrations of oxychlorine species (ClO2- + ClO3-) decreased during chlorination. By kinetic modelling, the ClO2- concentration after 24 h of chlorination was accurately predicted in synthetic waters but was largely overestimated in natural waters, possibly due to a ClO2- decay enhanced by high concentrations of chloride and in situ formed bromine from bromide. Understanding the chlorine-ClO2- reaction mechanism and the corresponding kinetics allows to potentially apply higher ClO2 doses during the pre-oxidation step, thus improving disinfection byproduct mitigation while keeping ClO2-, and if required, ClO3- below the regulatory limits. In addition, ClO2 was demonstrated to efficiently degrade haloacetonitrile precursors, either when used as pre-oxidant or when regenerated in situ during chlorination.

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Publisher Full Text (DOI)

Authors+Show Affiliations

Rougé V
Department of Chemistry, Curtin Water Quality Research Centre, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia; School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
Lee Y
School of Earth Sciences and Environmental Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea.
von Gunten U
Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf CH-8600, Switzerland; School of Architecture, Civil and Environmental Engineering (ENAC), Ecole Polytechnique Fédérale Lausanne (EPFL), Lausanne CH-1015, Switzerland.
Allard S
Department of Chemistry, Curtin Water Quality Research Centre, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia. Electronic address: s.allard@curtin.edu.au.

MeSH

ChloridesChlorineChlorine CompoundsDisinfectantsDisinfectionDrinking WaterHalogenationKineticsOxidantsOxidesWater Purification

Pub Type(s)

Journal Article

Language

eng

PubMed ID

35700645

Citation

Rougé, Valentin, et al. "Kinetic and Mechanistic Understanding of Chlorite Oxidation During Chlorination: Optimization of ClO2 Pre-oxidation for Disinfection Byproduct Control." Water Research, vol. 220, 2022, p. 118515.
Rougé V, Lee Y, von Gunten U, et al. Kinetic and mechanistic understanding of chlorite oxidation during chlorination: Optimization of ClO2 pre-oxidation for disinfection byproduct control. Water Res. 2022;220:118515.
Rougé, V., Lee, Y., von Gunten, U., & Allard, S. (2022). Kinetic and mechanistic understanding of chlorite oxidation during chlorination: Optimization of ClO2 pre-oxidation for disinfection byproduct control. Water Research, 220, 118515. https://doi.org/10.1016/j.watres.2022.118515
Rougé V, et al. Kinetic and Mechanistic Understanding of Chlorite Oxidation During Chlorination: Optimization of ClO2 Pre-oxidation for Disinfection Byproduct Control. Water Res. 2022 Jul 15;220:118515. PubMed PMID: 35700645.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Kinetic and mechanistic understanding of chlorite oxidation during chlorination: Optimization of ClO2 pre-oxidation for disinfection byproduct control. AU - Rougé,Valentin, AU - Lee,Yunho, AU - von Gunten,Urs, AU - Allard,Sébastien, Y1 - 2022/04/29/ PY - 2021/12/06/received PY - 2022/03/13/revised PY - 2022/04/25/accepted PY - 2022/6/15/pubmed PY - 2022/6/22/medline PY - 2022/6/14/entrez KW - Chlorate KW - Chlorine dioxide KW - Chlorite KW - Disinfection byproducts KW - Kinetic modelling SP - 118515 EP - 118515 JF - Water research JO - Water Res VL - 220 N2 - Chlorine dioxide (ClO2) applications to drinking water are limited by the formation of chlorite (ClO2-) which is regulated in many countries. However, when ClO2 is used as a pre-oxidant, ClO2- can be oxidized by chlorine during subsequent disinfection. In this study, a kinetic model for the reaction of chlorine with ClO2- was developed to predict the fate of ClO2- during chlorine disinfection. The reaction of ClO2- with chlorine was found to be highly pH-dependent with formation of ClO3- and ClO2 in ultrapure water. In presence of dissolved organic matter (DOM), 60-70% of the ClO2- was transformed to ClO3- during chlorination, while the in situ regenerated ClO2 was quickly consumed by reaction with DOM. The remaining 30-40% of the ClO2- first reacted to ClO2 which then formed chlorine from the DOM-ClO2 reaction. Since only part of the ClO2- was transformed to ClO3-, the sum of the molar concentrations of oxychlorine species (ClO2- + ClO3-) decreased during chlorination. By kinetic modelling, the ClO2- concentration after 24 h of chlorination was accurately predicted in synthetic waters but was largely overestimated in natural waters, possibly due to a ClO2- decay enhanced by high concentrations of chloride and in situ formed bromine from bromide. Understanding the chlorine-ClO2- reaction mechanism and the corresponding kinetics allows to potentially apply higher ClO2 doses during the pre-oxidation step, thus improving disinfection byproduct mitigation while keeping ClO2-, and if required, ClO3- below the regulatory limits. In addition, ClO2 was demonstrated to efficiently degrade haloacetonitrile precursors, either when used as pre-oxidant or when regenerated in situ during chlorination. SN - 1879-2448 UR - https://www.unboundmedicine.com/medline/citation/35700645/Kinetic_and_mechanistic_understanding_of_chlorite_oxidation_during_chlorination:_Optimization_of_ClO2_pre_oxidation_for_disinfection_byproduct_control_ DB - PRIME DP - Unbound Medicine ER -