Selective electrochemical capture and release of uranyl from aqueous alkali, lanthanide, and actinide mixtures using redox-switchable carboranes.

We report the selective electrochemical biphasic capture of the uranyl cation (UO ) from mixed-metal alkali (Cs), lanthanide (Nd, Sm), and actinide (Th, UO ) aqueous solutions to an organic, 1,2-dichloroethane (DCE), phase using the -substituted -carborane anion, [1,2-(PhPO)-1,2-CBH] (Cb). The reduced Cb is generated by electrochemical reduction of the -carborane, Cb, prior to mixing with the aqueous mixed-metal solution. Subsequent UO release from the captured product, [UO(Cb)], was performed by galvanostatic bulk electrolysis of the DCE phase and back-extraction of UO to a fresh aqueous phase. The selective capture and release of UO was confirmed by combined ICP-OES and NMR spectral analyses of the aqueous and organic phases, respectively, against the newly synthesized -carborane complexes, [[CoCp*][Cs(Cb)]], [CoCp*][Nd(Cb)], [CoCp*][Sm(Cb)], and [CoCp*][Th(Cb)].