Analytical Sciences

Voltammetric Study on Ion Transfer of Uranium(VI)Ion betweenAqueous and Nitrobenzene Phases in the Presence ofBis(diphenylphosphoryl)methane

Yoshihiro KITATSUJI* * , Hisao AOYAGI*, Zenko YOSHIDA* and SorinKIHARA**

*Advanced Science Research Center, Japan AtomicEnergy Research Institute, Tokai, Ibaraki 319-11, Japan
**Department of Chemistry, Kyoto Institute of Technology, Matsugasaki, Sakyoku, Kyoto 606, Japan

The ion transfer of UO2 2+ ionacross an aqueous(w)/nitrobenzene(NB) interface was investigated byion-transferpolarography using an aqueous electrolyte dropping electrode. It was foundthat the transfer of UO2 2+ from wto NB wasfacilitated by bis(diphenylphosphoryl)methane (BDPPM), and that thetransfer reaction had irreversible characteristics.A potential generated at the UO2 2+ ion-selective electrode, which was prepared while referring to iontransfer data,revealed a reversible Nernstian response against the concentration of theUO2 2+ ion in an aqueous samplesolution. Theirreversible nature of the UO2 2+ transfer observed in the polarogram resulted from such slowprocesses involved in the iontransfer reaction as the adsorption/desorption of BDPPM or theUO2 2+ -BDPPM complex at the w/NBinterface. Thefeasibility of the electrolytic separation of uranium from neptunium andplutonium on the basis of a selective ion-transferreaction is discussed. (Keywords: Polarography, ion transfer, aqueous/nitrobenzene interface,actinide, reversibility, separation, ion-selectiveelectrode)

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