Abstract
Transfer reactions at the interface of aqueous/organic solutions and redox reactions of actinide ions, such as U, Np and Pu, were investigated electrochemically as fundamental studies for the development of separation and speciation of such ions. A method to investigate ion transfer at a liquid/liquid interface based on controlled potential electrolysis and radioactivity measurement was developed and applied to determine standard ion transfer potential and complex formation constant of facilitated actinide ions transfer with an ionophore in the organic phase. A separation method was developed on the basis of the fundamental ion transfer data. Electrode redox reactions of actinide ions were also investigated. A mediator reaction and electrocatalysis were found to be involved in the reduction processes of actinide ions. In addition, a method to control the valence of actinide ions was successfully developed.
