ORALS

SESSION: MoltenMonAM-R3	Fehrmann International Symposium on Sustainable Molten Salt and Ionic Liquid Processing (6th Intl. Symp. on Sustainable Molten Salt and Ionic Liquid Processing)
Mon Nov, 5 2018 / Room: Bossa (150/3rd)
Session Chairs: Anders Riisager; Session Monitor: TBA

12:35: [MoltenMonAM04]
Use of Ionic Liquids for the Extraction of Actinides and Lanthanides: Synergistic Effects and Task-specific Extractants
Clotilde Gaillard¹ ; Maria Boltoeva² ; ¹CNRS, Villeurbanne, France; ²CNRS, Strasbourg, France;
Paper Id: 222 [Abstract]

Room-Temperature ionic liquids (IL) have been widely studied over the past several years for metal ion extraction, as their unique physico-chemical properties can be adjusted by selecting their ionic components for a specific need. For the extraction of metal ions like actinides (An) and lanthanides (Ln), IL can be used in several ways: as a solvent in the replacement of conventional molecular solvents [1], as an extracting molecule by using task-specific ionic liquid synthesised from a well-known extracting pattern, or as a synergistic agent in a traditional extractant/molecular solvent system [2]. This presentation will be focused on the extraction of actinides and lanthanides, to illustrate how the use of IL can result in higher efficiency and/or selectivity. With the support of spectroscopic techniques, UV-Vis and EXAFS, to identify the nature of extracted complexes and a modelling of the extraction data, we also demonstrate the mechanisms involved in the ion extraction, and compare them with those occurring in conventional extracting systems using molecular solvents. The advantages and drawbacks of the IL use will be discussed. Typical examples on the use of IL for the An and Ln separation will be presented. First, we will focus on how the extraction of uranium(VI) proceeds in a hydrophobic IL used in replacement of the usual organic solvent. Two extracting systems were investigated, using either TBP or a malonamide extractant. Then, we will present the An(III)/Ln(III) separation using a task-specific ionic liquid based on the CMPO pattern. We show that it allows a sequential separation of U(VI) and Eu(III)/Am(III), just by changing this ligand concentration in the organic phase. Finally, we will show how the extraction of uranium(VI) from nitric acid solutions with TODGA into the molecular solvent dichloroethane can be strongly enhanced by addition of a small amount of the ionic liquid C₄mimTf₂N in the organic phase, by the mean of a synergistic effect [3,4].

References:
[1] C. Gaillard, M. Boltoeva, I. Billard, S. Georg, V. Mazan, A. Ouadi, D. Ternova and C. Hennig, ChemPhysChem, 16 (2015) 16.
[2] G.A. Pribylova, I.V. Smirnov, A.P. Novikov, J. Radioanal. Nucl. Chem., 295 (2013) 83.
[3] A.N. Turanov, V.K. Karandashev, M. Boltoeva, C. Gaillard, V. Mazan, Sep. Purif. Technol. 164 (2016) 97.
[4] M. Boltoeva, C. Gaillard, S. Georg, A. N. Turanov, Sep. Purif. Technol. 203 (2018) 11.