Bromine Radical (Brand Br2•-) Reactivity with Dissolved Organic Matter and Brominated Organic Byproduct Formation

Yu Lei, Xin Lei, Paul Westerhoff, Xingyu Tong, Jianing Ren, Yangjian Zhou, Shuangshuang Cheng, Gangfeng Ouyang, Xin Yang

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Dissolved organic matter (DOM) is a major scavenger of bromine radicals (e.g., Brand Br2•-) in sunlit surface waters and during oxidative processes used in water treatment. However, the literature lacks quantitative measurements of reaction rate constants between bromine radicals and DOM and lacks information on the extent to which these reactions form brominated organic byproducts. Based on transient kinetic analysis with different fractions and sources of DOM, we determined reaction rate constants for DOM with Brranging from <5.0 × 107to (4.2 ± 1.3) × 108MC-1s-1, which are comparable with those of HObut higher than those with Br2•-(k = (9.0 ± 2.0) × 104to (12.4 ± 2.1) × 105MC-1s-1). Brand Br2•-attack the aromatic and antioxidant moieties of DOM via the electron transfer mechanism, resulting in Br-release with minimal substitution of bromine into DOM. For example, the total organic bromine was less than 0.25 μM (as Br) at environmentally relevant bromine radicals' exposures of ∼10-9M·s. The results give robust evidence that the scavenging of bromine radicals by DOM is a crucial step to prevent inorganic bromine radical chemistry from producing free bromine (HOBr/OBr-) and subsequent brominated byproducts.

Original languageEnglish (US)
Pages (from-to)5189-5199
Number of pages11
JournalEnvironmental Science and Technology
Volume56
Issue number8
DOIs
StatePublished - Apr 19 2022

Keywords

  • advanced oxidation processes (AOPs)
  • bromine radicals
  • dissolved organic matter (DOM)
  • halogenated byproducts
  • kinetics

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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