Chemical oxidation of dissolved organic matter by chlorine dioxide, chlorine, and ozone: Effects on its optical and antioxidant properties

Jannis Wenk, Michael Aeschbacher, Elisabeth Salhi, Silvio Canonica, Urs Von Gunten, Michael Sander

Research output: Contribution to journalArticle

107 Citations (Scopus)
168 Downloads (Pure)

Abstract

In water treatment dissolved organic matter (DOM) is typically the major sink for chemical oxidants. The resulting changes in DOM, such as its optical properties have been measured to follow the oxidation processes. However, such measurements contain only limited information on the changes in the oxidation states of and the reactive moieties in the DOM. In this study, we used mediated electrochemical oxidation to quantify changes in the electron donating capacities (EDCs), and hence the redox states, of three different types of DOM during oxidation with chlorine dioxide (ClO2), chlorine (as HOCl/OCl-), and ozone (O3). Treatment with ClO2 and HOCl resulted in comparable and prominent decreases in EDCs, while the UV light absorbances of the DOM decreased only slightly. Conversely, ozonation resulted in only small decreases of the EDCs but pronounced absorbance losses of the DOM. These results suggest that ClO2 and HOCl primarily reacted as oxidants by accepting electrons from electron-rich phenolic and hydroquinone moieties in the DOM, while O3 reacted via electrophilic addition to aromatic moieties, followed by ring cleavage. This study highlights the potential of combined EDC-UV measurements to monitor chemical oxidation of DOM, to assess the nature of the reactive moieties and to study the underlying reaction pathways.

Original languageEnglish
Pages (from-to)11147-11156
Number of pages10
JournalEnvironmental Science and Technology
Volume47
Issue number19
DOIs
Publication statusPublished - 1 Oct 2013

Fingerprint Dive into the research topics of 'Chemical oxidation of dissolved organic matter by chlorine dioxide, chlorine, and ozone: Effects on its optical and antioxidant properties'. Together they form a unique fingerprint.

  • Cite this