Modified diglycolamides for the An(III) + Ln(III) co-separation: evaluation by solvent extraction and time-resoved laser fluorescence spectroscopy

Andreas Wilden, Giuseppe Modolo, Steve Lange, Fabian Sadowski, Bjorn B. Beele, Andrej Skerencak- Frech, Petra J. Panak, M. Iqbal, Willem Verboom, Dirk Bosbach

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Abstract

The use of two recently developed diglycolamide-based extractants for the co-separation of trivalent actinides (An(III)) and lanthanides (Ln(III)) is described and compared to the well-known extractant TODGA (N,N,N’,N’-tetraoctyl diglycolamide). The addition of one or two methyl groups to the central methylene carbon atoms of the TODGA molecule leads to a reduction of the extraction efficiency for An(III) and Ln(III). This is attributed to a lower complex formation constant, which was proven by Time-Resolved Laser Fluorescence Spectroscopy (TRLFS). Conditional stability constants were determined by solvent extraction and TRLFS. The reduction in extraction efficiency leads to overall reduced distribution ratios of all tested metal ions, including Sr(II). The reduced Sr(II) extraction is beneficial as a co-extraction in a solvent extraction process could be avoided, while an efficient extraction of the desired An(III) and Ln(III) is still achieved. Furthermore, this might be a benefit, as the stripping behavior might be improved, even at moderate nitric acid concentrations. The slightly higher affinity of the diglycolamides towards Eu(III) over Am(III) is represented by all ligands, although the selectivity is rather low. This results in promising extraction properties of the modified diglycolamides towards the development of continuous solvent extraction processes.
Original languageUndefined
Pages (from-to)119-137
Number of pages19
JournalSolvent extraction and ion exchange
Volume32
Issue number2
DOIs
Publication statusPublished - 2014

Keywords

  • METIS-308535
  • IR-95111

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