The aqueous degradation of butylated hydroxyanisole by UV/S 2O82-: Study of reaction mechanisms via dimerization and mineralization

Tim K. Lau, Wei Chu, Nigel J.D. Graham

Research output: Journal article publicationJournal articleAcademic researchpeer-review

358 Citations (Scopus)

Abstract

Three distinctive phases of BHA reactivity toward UV/S2O 82- at acidic, neutral, and basic pH range were examined, where 80-100% mineralization has been observed within an hour of irradiation under 254 nm. A reduction in solution pH during the reaction was observed mainly due to the complete conversion of S2O82- to sulfate ion together with proton generation. Seven measurable intermediates were found via an oxidation and dimerization process at all tested pH levels. The BHA decay mechanisms are quite different in acidic condition and at other pH levels. There are three unique intermediates that are only detectable at pH 3 via two additional pathways. This is due to the generation of weaker oxidants or radicals which results in a slower degradation of the BHA, and therefore, the accumulation of these intermediates to detectable levels. The rate of BHA decay generally increases from low to high pH levels; however, the corresponding mineralization at higher pH is retarded due to the futile process of recombining radicals and involvement of intermediates. Therefore, neutral pH was suggested to be the optimum condition in terms of mineralization and moderate efficiency in removing BHA.
Original languageEnglish
Pages (from-to)613-619
Number of pages7
JournalEnvironmental Science and Technology
Volume41
Issue number2
DOIs
Publication statusPublished - 15 Jan 2007

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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