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Kitatsuji, Yoshihiro; Kimura, Takaumi; Kihara, Sorin*
Journal of Electroanalytical Chemistry, 641(1-2), p.83 - 89, 2010/03
Unique current-time relations were observed during the controlled potential electrolysis for the reduction of Np(V) to Np(IV) or Np(III) at a Au or Pt electrode. The reduction process of Np(V) was elucidated based on bulk electrolysis and voltammetry: Though Np(V) is not reduced directly at a Au electrode, it is reduced by chemical reaction with Np(III) which is produced by the electrode reduction of Np(IV). The reduction of Np(V) at a Pt electrode is initiated by the electrocatalytic reduction to Np(IV) with the hydrogen atom which is produced by the electrode reduction of H
and adsorbed on the Pt electrode surface. The Np(IV) produced functions as an electron transfer mediator to reduce Np(V) similarly to the reaction at a Au electrode. The above described catalytic reduction processes of Np(V) were elucidated with the aid of digital simulation. Methods useful for the preparation of Np(IV) and Np(III) by bulk electrolysis were proposed based on the experimental results.
Okugaki, Tomohiko*; Kitatsuji, Yoshihiro; Kasuno, Megumi*; Yoshizumi, Asuka*; Kubota, Hiroki*; Shibafuji, Yayoi*; Maeda, Koji*; Yoshida, Zenko; Kihara, Sorin*
Journal of Electroanalytical Chemistry, 629(1-2), p.50 - 56, 2009/04
A high performance electrochemical solvent extraction method was developed based on the quantitative transfer of ions from an aqueous, W, to an organic solution, O. It was realized by applying a potential difference between W and O. The cell was composed of a porous Teflon tube immersed with O, a Ag wire inserted into the tube, a Pt wire placed outside the tube. When W containing ions was forced to flow through the narrow gap between the tube and Ag wire, and potential was applied, a very rapid quantitative ion transfer was attained. When O containing extractant, more than 99% of U(VI) in W was extracted during the residence (e.g., 40 s) in the cell. The fundamental feature of the extraction system was investigated, taking into account the application of the system to the extraction of actinide, lanthanide, Sr or Cs ions. The use of a column electrode system connected before the extraction system was examined in order to adjust the oxidation state of the element to that desired.
organic solution interface in chelate extractionUehara, Akihiro*; Kasuno, Megumi*; Okugaki, Tomohiko*; Kitatsuji, Yoshihiro; Shirai, Osamu*; Yoshida, Zenko; Kihara, Sorin*
Journal of Electroanalytical Chemistry, 604(2), p.115 - 124, 2007/06
The distribution ratio of a metal ion between an aqueous solution and an organic solution in solvent extraction with a chelating agent was evaluated by using physicochemical constants determined electrochemically such as standard Gibbs energies for transfers of the ions, the overall complex formation constants and the acid dissociation constants of the chelating agent. The distribution ratio thus evaluated agreed well with those determined by the distribution experiment.
Yoshizumi, Asuka*; Uehara, Akihiro*; Kasuno, Megumi*; Kitatsuji, Yoshihiro; Yoshida, Zenko; Kihara, Sorin*
Journal of Electroanalytical Chemistry, 581(2), p.275 - 283, 2005/08
no abstracts in English
Shirai, Osamu*; Yamada, Hajimu*; Onuki, Toshihiko; Yoshida, Yumi*; Kihara, Sorin*
Journal of Electroanalytical Chemistry, 570(2), p.219 - 226, 2004/09
Times Cited Count：26 Percentile：58.46(Chemistry, Analytical)no abstracts in English
organic solution interfaceUehara, Akihiro*; Yoshida, Zenko; Yoshida, Yumi*; Kitatsuji, Yoshihiro; Kasuno, Megumi*; Maeda, Koji*; Kihara, Sorin*
Journal of Electroanalytical Chemistry, 563(2), p.257 - 267, 2004/03
no abstracts in English
Kitatsuji, Yoshihiro; Yoshida, Zenko; Kudo, Hiroshi*; Kihara, Sorin*
Journal of Electroanalytical Chemistry, 520(1-2), p.133 - 144, 2002/02
no abstracts in English
