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Direct Emission of I_2 Molecule and IO Radical from the Heterogeneous Reactions of Gaseous Ozone with Aqueous Potassium Iodide Solution

Sakamoto, Yosuke and Yabushita, Akihiro and Kawasaki, Masahiro and Enami, Shinichi (2009) Direct Emission of I_2 Molecule and IO Radical from the Heterogeneous Reactions of Gaseous Ozone with Aqueous Potassium Iodide Solution. Journal of Physical Chemistry A, 113 (27). pp. 7707-7713. ISSN 1089-5639.

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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.

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Enami, Shinichi0000-0002-2790-7361
Additional Information:© 2009 American Chemical Society. Received: April 16, 2009; Revised Manuscript Received: May 21, 2009. Publication Date (Web): June 16, 2009. The authors appreciate Ms. S. Hayase for help with experiments. We greatly appreciate Dr. A. J. Colussi of California Institute of Technology and Dr. Chad. D. Vecitis of Yale University for valuable discussions. S.E. thanks the JSPS Research Fellowships for Young Scientists. This work is partly supported by a Grant-in-Aid from JSPS (#20245005). Supporting Information: Experimental details. This material is available free of charge via the Internet at
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Japan Society for the Promotion of Science (JSPS)20245005
Issue or Number:27
Record Number:CaltechAUTHORS:20090901-131930555
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15526
Deposited By: George Porter
Deposited On:09 Sep 2009 18:17
Last Modified:03 Oct 2019 00:59

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