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Determining the stoichiometry of An(III)-DMDOHEMA complexes formed during extraction

Weßling, Patrik; Trumm, Michael; Geist, Andreas ORCID iD icon; Panak, Petra J.

Abstract (englisch):

N,N'-dimethyl,N,N'-dioctylhexylethoxymalonamide (DMDOHEMA) is used to separate An(III) and Ln(III) from fission products in several liquid-liquid extraction processes (DIAMEX, EXAm, GANEX)1-2 that aim at recycling actinides. One key to understand these processes is the stoichiometry of the complexes formed during extraction. Time-resolved laser fluorescence spectroscopy (TRLFS) poses, in contrast to extraction experiments, a technique to study the inner sphere coordination of fluorescent metal ions (e.g. Cm(III)). Therefore, the stoichiometry of the complexes can be determined. The presented work focuses on the complexation of Cm(III) with DMDOHEMA studied by TRLFS in mono- and biphasic systems. First, stability constants of the Cm(III)-DMDOHEMA complexes are determined in 1-octanol. The formation of [Cm(DMDOHEMA)n]3+ with log’1 = 2.63 ± 0.33, log’2 = 3.99 ± 0.48, log’3 = 4.34 ± 0.52 is confirmed. Furthermore, fluorescence lifetime measurements indicate the formation of a 1:4 complex. Furthermore, biphasic experiments are performed with Cm(III) and DMDOHEMA in dependence of the DMDOHEMA, nitric acid and nitrate concentration. TRLFS measurements of the different organic phases reveal a predominance of two species at max = 601.3 nm (I) and 604.2 nm (II). ... mehr


Zugehörige Institution(en) am KIT Institut für Nukleare Entsorgung (INE)
Publikationstyp Vortrag
Publikationsdatum 14.05.2018
Sprache Englisch
Identifikator KITopen-ID: 1000083469
HGF-Programm 32.01.11 (POF III, LK 01) Extraktions- und Koordinationschemie der Actiniden
Veranstaltung 18th Radiochemical Conference (RadChem 2018), Marienbad, Tschechien, 13.05.2018 – 18.05.2018
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