Direct emission of I 2 molecule and IO radical from the heterogeneous reactions of gaseous ozone with aqueous potassium iodide solution

Yosuke Sakamoto, Akihiro Yabushita, Masahiro Kawasaki, Shinichi Enami

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)

Abstract

Recent studies indicated that gaseous halogens mediate key tropospheric chemical processes. The inclusion of halogen-ozone chemistry in atmospheric box models actually closes the ∼50% gap between estimated and measured ozone losses in the marine boundary layer. The additional source of gaseous halogens is deemed to involve previously unaccounted for reactions of O 3(g) with sea surface water and marine aerosols. Here, we report that molecular iodine, I 2(g), and iodine monoxide radical, IO(g), are released ([I 2(g)] > 100[IO(g)]) during the heterogeneous reaction of gaseous ozone, O 3(g), with aqueous potassium iodide, KI(aq). It was found that (1) the amounts of I 2(g) and IO(g) produced are directly proportional to [KI(aq)] up to 5 mM and (2) IO(g) yields are independent of bulk pH between 2 and 11, whereas I 2(g) production is markedly enhanced at pH < 4. We propose that O 3(g) reacts with I - at the air/water interface to produce I 2(g) and IO(g) via HOI and IOOO - intermediates, respectively.

Original languageEnglish
Pages (from-to)7707-7713
Number of pages7
JournalJournal of Physical Chemistry A
Volume113
Issue number27
DOIs
Publication statusPublished - Jul 9 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry

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