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Oxidative decomposition of ammonium ion with ozone in the presence of cobalt and chloride ions for the treatment of radioactive liquid waste
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| Title: | Oxidative decomposition of ammonium ion with ozone in the presence of cobalt and chloride ions for the treatment of radioactive liquid waste |
| Authors: | Aihara, Haruka Browse this author | | Watanabe, Sou Browse this author →KAKEN DB | | Shibata, Atsuhiro Browse this author | | Mahardiani, Lina Browse this author | | Otomo, Ryoichi Browse this author →KAKEN DB | | Kamiya, Yuichi Browse this author →KAKEN DB |
| Keywords: | Radioactive liquid waste | | Ammonium ion | | Ozone oxidation | | Cobalt ion | | pH dependence |
| Issue Date: | Sep-2021 |
| Publisher: | Elsevier |
| Journal Title: | Progress in Nuclear Energy |
| Volume: | 139 |
| Start Page: | 103872 |
| Publisher DOI: | 10.1016/j.pnucene.2021.103872 |
| Abstract: | To prevent unexpected accidents at nuclear facilities caused by accumulated ammonium nitrate in an aqueous liquid waste containing ammonium salts and nitric acid, NH4+ in the liquid waste must be decomposed under mild reaction conditions. In this study, we investigated the oxidative decomposition of NH4+ with O-3 at 333 K in the presence of a homogeneous Co2+ catalyst and Cl in the wide pH range of the test solution. The reaction behavior was greatly affected by pH of the test solution. In a basic solution at pH 12, high conversion of NH4+ was obtained even in the absence of Co2+ and Cl, and the main product was NO3. However, Co2+ and Cl in the solution greatly enhanced the decomposition rate of NH4+ in acidic to mild basic solutions (pH 1-8), while only low conversion of NH4+ was observed unless both Co2+ and Cl were present. For the reaction with Co2+ and Cl in the solutions, NH4+ was transformed mainly into chloramines (NHxCl3 x, x = 1-3) by the reaction with HClO, which was formed by the reaction of Cl with O-3 catalyzed by the homogeneous Co2+ catalyst, and led to the high decomposition rate of NH4+. Cl suppressed the formation of the precipitate CoO(OH) during the reaction and consequently the Co2+ catalyst stably existed in the reaction solution, which was another reason for the high decomposition rate of NH4+ in the presence of Cl. Owing to the swift decomposition of NH4+ under mild reaction conditions and small formation of secondary waste, the oxidative decomposition of NH4+ in the presence of the homogeneous Co2+ catalyst and Cl is suitable and applicable for the treatment of the aqueous liquid waste containing ammonium salts and nitric acid. |
| Rights: | © 2021. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ | | https://creativecommons.org/licenses/by-nc-nd/4.0/ |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/90451 |
| Appears in Collections: | 環境科学院・地球環境科学研究院 (Graduate School of Environmental Science / Faculty of Environmental Earth Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 神谷 裕一
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