Spectroscopic study of the uranium(IV) complexation by organic model ligands in aqueous solution


Spectroscopic study of the uranium(IV) complexation by organic model ligands in aqueous solution

Schmeide, K.; Bernhard, G.

In the present study, the model ligands citric acid and glutaric acid as well as mandelic acid and glycolic acid were chosen for the uranium(IV) complexation. These ligands stand for a variety of organic ligands in aqueous systems. The complex formation constants for the uranium(IV) complexation were determined applying UV-Vis absorption spectroscopy. Thereby, the hydrogen ion concentration and the ionic strength were varied.
For instance, the complexation of uranium(IV) with citric acid has been investigated in dependence on hydrogen ion concentration (1 M, 0.5 M, 0.1 M and 0.05 M). Thereby, the formation of 1:1 and 1:2 complexes was detected in the citrate media. The stability constants for 1:1 and 1:2 uranium(IV) citrate complexes of the type MpHqLr were determined with log ß101 = 13.5 ± 0.2 and log ß102 = 25.1 ± 0.2. The obtained log ß fit well in the known series of log ß determined for the complexation of further tetravalent actinides (e.g., Pu(IV), Np(IV), Th(IV)) by citric acid.

Keywords: uranium; tetravalent; complexation; citric acid

  • Lecture (Conference)
    5th International Conference Uranium Mining Hydrogeology (UMH V), 14.-18.09.2008, Freiberg, Germany
  • Contribution to external collection
    Broder J. Merkel, Andrea Hasche-Berger: Uranium, Mining and Hydrogeology, Berlin: Springer Verlag, 2008, 978-3-540-87745-5, 591-598

Permalink: https://www.hzdr.de/publications/Publ-10923
Publ.-Id: 10923