常温無機イオン液体と有機溶媒の界面でのウランの無電解析出の実現

2015 Fiscal Year Annual Research Report

• Project/Area Number: 25420905
• Research Institution: Kyoto University
• Principal Investigator: 上原 章寛 京都大学, 原子炉実験所, 助教 (30402952)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: ウラン / 電解還元 / 液液界面 / 析出 / 乾式再処理 / ナノ粒子

Outline of Annual Research Achievements

使用済燃料を溶解した後、主成分であるウランをすべての工程に先立って分離回収することは、燃料処理過程の簡素化や廃棄物の減量に貢献する。ところで申請者らは、放射線耐性の強い無機水和物溶融体（塩化カルシウム六水和物）中に溶解したウラニルイオンが、常温で電解によって二酸化ウランとして析出・回収できることを見出している。しかし、固体の電極と溶液の界面の面積は、溶液の体積に比べて小さいので、固体電極を用いるとき、析出・回収の効率を向上させることが困難である。本研究では固体電極の代わりに電解質を含む有機溶媒を電極として用いて、水溶液と有機溶液の界面でウランイオンを還元して電析させることを目指した。
本年度は、デカメチルフェロセンを還元体として含む有機相とウランイオン(IV)を含む水溶液界面での酸化還元反応について電気化学的に調査し、ウランイオンが界面で還元されることを確認した。界面での酸化還元反応は非可逆的で極めて遅い反応であることが分かった。ウランイオンの還元のされやすさは、水溶液の酸性度に依存し、酸性度が高いほどウラン(IV)への還元が生じやすく、U4+を生成することが分かった。

Research Products

• [Int'l Joint Research] University of Manchester/University of Leeds/Diamond Light Source(United Kingdom)
  • Country Name: United Kingdom
  • Counterpart Institution: University of Manchester/University of Leeds/Diamond Light Source
• [Journal Article] An in-situ X-ray absorption spectroelectrochemical study of the electroreduction of uranium ions in HCl, HNO3, and Na2CO3 solutions (2016)
  • Author(s): Akihiro Uehara, Toshiyuki Fujii, Hajimu Yamana, and Yoshihiro Okamoto
  • Journal Title: Radiochimica Acta Volume: 104 Pages: 1-9
  • DOI: 10.1515/ract-2015-2436
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Detection and characterisation of sub-critical nuclei during reactive Pd metal nucleation by X-ray absorption spectroscopy (2016)
  • Author(s): S.-Y. Chang, Y. Grunder, S. G. Booth, L. B. Molleta, A. Uehara, J. F. W. Mosselmans, G. Cibin, V.-T. Pham, L. Nataf, R. A. W. Dryfe and S. L. M. Schroeder
  • Journal Title: CrystEngComm Volume: 18 Pages: 674-682
  • DOI: 10.1039/c5ce01883h
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] 高濃度電解質水溶液中のウランイオンの酸化還元反応 (2016)
  • Author(s): 上原章寛, 藤井俊行
  • Journal Title: 溶融塩および高温化学 Volume: 59 Pages: 14-19
• [Journal Article] Gold Deposition at a Free-Standing Liquid/Liquid Interface: Evidence for the Formation of Au(I) by Microfocus X-ray Spectroscopy (μXRF and μXAFS) and Cyclic Voltammetry (2015)
  • Author(s): Samuel G. Booth, Akihiro Uehara, Sin Yuen Chang, J. Fred W. Mosselmans, Sven L. M. Schroeder, and Robert A. W. Dryfe
  • Journal Title: Journal of Physical Chemistry C Volume: 119 Pages: 16785－16792
  • DOI: 10.1021/acs.jpcc.5b05127
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Electrochemical Insight into the Brust-Schiffrin Synthesis of Au Nanoparticles (2015)
  • Author(s): Akihiro Uehara, Samuel G. Booth, Sin Yuen Chang, Sven L. M. Schroeder, Takahito Imai, Teruo Hashimoto, J. Frederick W. Mosselmans, and Robert A. W. Dryfe
  • Journal Title: Journal of the American Chemical Society Volume: 137 Pages: 15135-15144
  • DOI: 10.1021/jacs.5b07825
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Redox and Ligand Exchange during the Reaction of Tetrachloroaurate with Hexacyanoferrate(II) at a Liquid-Liquid Interface: Voltammetry and X-ray Absorption Fine-Structure Studies (2015)
  • Author(s): Akihiro Uehara, Sin-Yuen Chang, Samuel G. Booth, Sven L. M. Schroeder, J. Frederick W. Mosselmans, and Robert A.W. Dryfe
  • Journal Title: Electrochimica Acta Volume: 109 Pages: 997-1006
  • DOI: http://dx.doi.org/10.1016/j.electacta.2015.12.108
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Presentation] 濃厚電解質溶液中でのアクチノイドイオンの酸化還元反応 (2016)
  • Author(s): 上原章寛
  • Organizer: 溶融塩委員会
  • Place of Presentation: 東京都市大学（神奈川県・川崎市）
  • Year and Date: 2016-01-27 – 2016-01-27
  • Invited
• [Presentation] Electrochemical insight into the Brust-Schiffrin synthesis of Au nanoparticles (2016)
  • Author(s): Akihiro Uehara, Samuel G. Booth, Sin Yuen Chang, Sven L.M. Schroeder, Takahito Imai, Teruo Hashimoto, J. Frederick W. Mosselmans, and Robert A.W. Dryfe
  • Organizer: Faraday Discussion, Nanoparticle Assembly: From Fundamentals to Applications
  • Place of Presentation: Mumbai, India
  • Year and Date: 2016-01-07 – 2016-01-09
  • Int'l Joint Research
• [Presentation] 金ナノ粒子合成メカニズムの 液液界面イオン移動ボルタンメトリーによる解明 (2015)
  • Author(s): 上原章寛, S.G. Booth, S.Y. Chang, 今井崇人, S.L.M. Schroeder, R.A.W. Dryfe
  • Organizer: ポーラログラフィーおよび電気分析化学討論会
  • Place of Presentation: イーグレひめじ（兵庫県・姫路市）
  • Year and Date: 2015-11-24 – 2015-11-25
• [Presentation] ドデカンチオールを用いた金ナノ粒子合成過程の液液界面イオン移動ボルタンメトリーに基づく理解 (2015)
  • Author(s): 上原章寛, S.G. Booth, S.Y. Chang, S.L.M Schroeder, R.A.W. Dryfe
  • Organizer: 日本分析化学会第64年会
  • Place of Presentation: 九州大学（福岡県・福岡市）
  • Year and Date: 2015-09-09 – 2015-09-11
• [Presentation] Evidence for a Strongly Bound Solvent Molecules: XANES and EXAFS of Aqueous Au(III) Cyanide (2015)
  • Author(s): Sin-Yuen Chang, Samuel Booth, Robert Dryfe, Akihiro Uehara, Konstantin Ignatyev, Fred Mosselmans, Sven Schroeder
  • Organizer: XAFS16, 16th International Conference on X-ray Absorption Fine Structure
  • Place of Presentation: Karlsruhe, Germany
  • Year and Date: 2015-08-23 – 2015-08-28
  • Int'l Joint Research
• [Presentation] In Situ XAS Studies of Pd Nanoparticle Nucleation at an Interface of Two Immiscible Phases (2015)
  • Author(s): S.-Y. Chang, S.G. Booth, Y. Grunder, L.B. Molleta, A. Uehara, J.F.W. Mosselmans, G. Cibin, R.A.W. Dryfe, S.L.M. Schroeder
  • Organizer: XAFS16, 16th International Conference on X-ray Absorption Fine Structure
  • Place of Presentation: Karlsruhe, Germany
  • Year and Date: 2015-08-23 – 2015-08-28
  • Int'l Joint Research
• [Presentation] Why Au L3 XANES White Line Intensities Can Be a Poor Predictor of Oxidation State (2015)
  • Author(s): Sin-Yuen Chang, Samuel G. Booth, Akihiro Uehara, Konstantin Ignatyev, J. Fred W. Mosselmans, Robert A.W. Dryfe, and Sven L. M. Schroeder
  • Organizer: XAFS16, 16th International Conference on X-ray Absorption Fine Structure
  • Place of Presentation: Karlsruhe, Germany
  • Year and Date: 2015-08-23 – 2015-08-28
  • Int'l Joint Research
• [Presentation] Brust-Schiffrin Synthesis: A mechanistic study (2015)
  • Author(s): S. G. Booth, A. Uehara, S.-Y. Chang, J. F. W. Mosslemans, S. L. M. Schroeder and R. A. W. Dryfe
  • Organizer: XAFS16, 16th International Conference on X-ray Absorption Fine Structure
  • Place of Presentation: Karlsruhe, Germany
  • Year and Date: 2015-08-23 – 2015-08-28
  • Int'l Joint Research
• [Presentation] Structure and Bonding in Au(I) Chloride Species: A Critical Examination of X-ray Absorption Spectroscopy (XAS) Data (2015)
  • Author(s): S-Y Chang, SG Booth, A Uehara, K Ignatyev, JFW Mosselmans, RAW Dryfe, SLM Schroeder
  • Organizer: GOLD2015
  • Place of Presentation: Cardiff University, UK
  • Year and Date: 2015-07-26 – 2015-07-29
  • Int'l Joint Research
• [Presentation] Brust-Schiffrin Synthesis: A mechanistic study (2015)
  • Author(s): S. G. Booth, A. Uehara, S.-Y. Chang, J. F. W. Mosslemans, S. L. M. Schroeder and R. A. W. Dryfe
  • Organizer: GOLD2015
  • Place of Presentation: Cardiff University, UK
  • Year and Date: 2015-07-26 – 2015-07-29
  • Int'l Joint Research
• [Presentation] Electrochemical insight into the Brust-Schiffrin synthesis of Au nanoparticles (2015)
  • Author(s): A. Uehara, S. G. Booth, S.-Y. Chang, S.L.M. Schroeder, T. Imai, T. Hashimoto, J.F.W. Mosselmans, R.A.W. Dryfe
  • Organizer: 48th Heyrovsky Discussion
  • Place of Presentation: Trest, Czech Republic
  • Year and Date: 2015-06-14 – 2015-06-19
  • Int'l Joint Research
• [Presentation] ドデカンチオールを用いた金ナノ粒子生成過程における金(I)の存在 (2015)
  • Author(s): 上原 章寛, S.G. Booth, S.Y. Chang, S.L.M. Schroeder, R.A.W. Dryfe
  • Organizer: 日本分析化学会討論会
  • Place of Presentation: 山梨大学（山梨県・甲府市）
  • Year and Date: 2015-05-23 – 2015-05-24