Technetium-99 (99Tc t1/2: 2.1x 105 years; βmax: 293.7 keV) is a high-yield (6%) fission product in light-water reactors, which presents major challenges in separations and containment technologies. The use of ionic liquids (IL) as a possible alternative media for separations is being explored. In order to access the potential use of ILs for separations, a fundamental understanding of the interactions of technetium and ILs must be understood. We are investigating speciation of technetium in neat ILs as well acid-IL mixtures. One system studied is the speciation of TcO4- in the IL Trimethylbutylammonium Bistriflimide (N1114 NTf2) and Bistriflimidic acid (HNTf2). HNTf2 is a known super acid and recently been shown to be an even stronger acid when dissolved in (IL) bearing the NTf2 anion. N-alkylammonium pertechnetate (TcO4-) salts were combined with varying concentrations of HNTf2 in an IL with the corresponding cation as the Tc salt. The speciation was studied using UV-VIS, 1H and 99Tc NMR, and XANES. Preliminary results suggest that the TcO4- anion is protonated in the IL to form HTcO4 (pertechnic acid). Pertechnic acid is typically generated using large amounts of a non-coordinating acid i.e Sulfuric acid (&gt;9M) in aqueous media. The species formed in acid-IL solution is observed using far less acid (&lt;100mM). The reactivity of the pertechnic acid species in the ionic liquid is also investigated. In another study, the speciation of technetium as Tc(V) oxo or Tc(VI) nitrido incorporated into a polyoxometalate is investigated electrochemically in IL and in acetonitrile. The IL extends the viable electrochemical range and Tc (IV), Tc(V), Tc(VI) and Tc(VII) species are identified

Speciation of technetium in ionic liquids

255th National Meeting (2018)

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