TY - JOUR
T1 - Experimental Determination of the Photooxidation of Aqueous I- as a Source of Atmospheric I2
AU - Watanabe, Kosuke
AU - Matsuda, Shohei
AU - Cuevas, Carlos A.
AU - Saiz-Lopez, Alfonso
AU - Yabushita, Akihiro
AU - Nakano, Yukio
N1 - Funding Information:
We would like to thank T. Horiguchi, S. Suzuki, T. Takezawa, S. Sakai, and S. Shibata for their help with experiments. We also thank Prof. S. Aloisio of California State University (Channel Islands) for his valuable discussions. We would like to thank Enago (www.enago.jp) for the English language review. This work was supported by Grant-in-Aids for Scientific Research from Japan Society for the Promotion of Science (JSPS) No. 18K03740.
Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2019/4/18
Y1 - 2019/4/18
N2 - The chemistry of iodine plays an important role in the oxidizing capacity of the global marine atmosphere. In this study, we experimentally determine the photooxidation parameters of iodide ions in aqueous phase (I-(aq)) and estimate the subsequent emission of gaseous iodine molecules (I2(g)) into the atmosphere. The values of the molar absorption coefficient (ϵiodide(λ)) and the photooxidative quantum yields (φiodide(λ)) of I-(aq) in the range of 290-500 nm were determined. The influence of pH and dissolved oxygen (DO) on the values of φiodide(λ) was also investigated. The emission of I2(g) into the atmosphere following the photooxidation of I-(aq) in deionized water solution (pH 5.6, DO 7.8 mg L-1) and artificial seawater solution (pH 8.0, DO 7.0 mg L-1) was estimated to be (2.2 × 10-8 × [I-(aq)]sea) and (1.8 × 10-8 × [I-(aq)]sea) mol L-1 s-1, respectively. Using a global chemistry-climate model, we estimated that the photooxidation of I-(aq) can increase the atmospheric iodine budget by up to ∼8% over some oceanic regions.
AB - The chemistry of iodine plays an important role in the oxidizing capacity of the global marine atmosphere. In this study, we experimentally determine the photooxidation parameters of iodide ions in aqueous phase (I-(aq)) and estimate the subsequent emission of gaseous iodine molecules (I2(g)) into the atmosphere. The values of the molar absorption coefficient (ϵiodide(λ)) and the photooxidative quantum yields (φiodide(λ)) of I-(aq) in the range of 290-500 nm were determined. The influence of pH and dissolved oxygen (DO) on the values of φiodide(λ) was also investigated. The emission of I2(g) into the atmosphere following the photooxidation of I-(aq) in deionized water solution (pH 5.6, DO 7.8 mg L-1) and artificial seawater solution (pH 8.0, DO 7.0 mg L-1) was estimated to be (2.2 × 10-8 × [I-(aq)]sea) and (1.8 × 10-8 × [I-(aq)]sea) mol L-1 s-1, respectively. Using a global chemistry-climate model, we estimated that the photooxidation of I-(aq) can increase the atmospheric iodine budget by up to ∼8% over some oceanic regions.
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U2 - 10.1021/acsearthspacechem.9b00007
DO - 10.1021/acsearthspacechem.9b00007
M3 - Article
AN - SCOPUS:85063151574
SN - 2472-3452
VL - 3
SP - 669
EP - 679
JO - ACS Earth and Space Chemistry
JF - ACS Earth and Space Chemistry
IS - 4
ER -
