Effect of aluminum metal surface on oxidation of iodide under gamma irradiation conditions

The effects of aluminum surface on I− oxidation under gamma irradiation were investigated. Without irradiation, only O2 oxidized I− at pH < 2, and aluminum expedited the oxidation reaction. With irradiation, the radiolysis products from water and air oxidized I− into I3-.\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\text{I}}_{3}}^{ - } .$$\end{document} At pH < 2, O2 generated by water radiolysis additionally oxidized I−. However, at pH > 6, the H2O2 radiolysis product reduced I3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\text{I}}_{3}}^{ - }$$\end{document} into I−. A smaller amount of I3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\text{I}}_{3}}^{ - }$$\end{document} was observed in pH 1.9 and 3.3 solutions in contact with aluminum under irradiation because oxidants preferentially oxidize aluminum rather than I−. Moreover, for pH < 6.0, even less I3-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\text{I}}_{3}}^{ - }$$\end{document} was formed by aluminum exposed to air because air radiolysis products also preferentially oxidized aluminum.