The extraction of pertechnetate ions from aquous solutions containing various concentrations of nitric acid into hydrophobic ionic liquids (ILs) has been examined at 25, 50 and 70 °C. The results show that the distribution ratio of Tc (DTc) between both phases weakly depends on the temperature and HNO3 concentration when IL’s with relatively short aliphatic chains are used. The DTc obtained for all examined ILs, except methyltrioctylammonium bis(trifluoromethylsulfonyl)imide and 1-butyl-3-methylimidasolium hexafluorophosphate, are lower than 1.5. In the case of methyltrioctylammonium bis(trifluoromethylsulfonyl)imide a decrease of Tc concentration in aqueous solutions facilitates pertechnetate extraction into the organic phase.
1 July 2021 in Journal of Electroanalytical Chemistry
Physicochemical properties of a liquid mixture containing choline chloride (ChCl) and acetic acid (AA) with a molar ratio of 1:2 were analyzed to determine its suitability for electrochemical studies. Viscosity, ionic conductivity, and density values as well as the width of the electrochemical window of the ChCl:AA mixture show that this liquid can be used as a supporting electrolyte in electrochemical studies. This was confirmed by the results of electrochemical studies on a model red-ox system of o-tolidine. Additional electrochemical tests revealed the dissolution of solid Pt in ChCl:FA. The ChCl:AA solution was also used as a background electrolyte in preliminary studies on the electrochemical reduction of pertechnetates. Cyclic voltammetry and UV-Vis spectroscopy experiments reveal a multi-path process which leads to the formation of Tc(IV or III) ionic species.
17 May 2018 in Journal of Radioanalytical and Nuclear Chemistry
Redox interaction of reduced technetium forms and technetium(VII) with neptunium(III), neptunium(IV) and neptunium(VI) have been investigated using electrochemical and spectroscopic (Vis–NIR) techniques. The neptunium species most stable in 4 M H2SO4, i.e. Np(IV) ions, do not reduce Tc(VII) in contrast to Np(VI) ions which oxidize Tc(IV) species to Tc(VII). The interaction of pertechnetates with Np(III) leads to formation of Tc(IV) species. The Vis–NIR measurements showed the generation of intermediate Tc(V) and Np(V) forms during the oxidation of Tc(IV) and competitive reduction of Np(VI). Tc(V) and Np(V) forms are characterised by the bands at 460 and 980 nm respectively.
An overview of the reported electrochemistry studies on the chemistry of the element for targets for isotope production in ionic liquids (ILs) is provided. The majority of investigations have been dedicated to two aspects of the reactive element chemistry. The first part of this review presents description of the cyclotron targets properties, especially physicochemical characterization of irradiated elements. The second part is devoted to description of the electrodeposition procedures leading to obtain elements or their alloys coatings (e.g., nickel, uranium) as the targets for cyclotron and reactor generation of the radioisotopes. This review provides an evaluation of the role ILs can have in the production of isotopes.