Complexation of Np(V) in aqueous solutions
Various parameters affecting the diffusion coefficient of neptunium(V) in clay systems have been studied, such as clay mineralogy, the charge compensating cation in the clay, the ionic strength of a background perchlorate solution and the presence of three organic ligands. In the present study, several different, well established techniques have been used to obtain stability constants for the neptunium systems. NpO(2)(+) complexes were formed; the complexes were mainly 1:1 in the case of EDTA and citrate but with the possibility of larger complexes at higher ligand concentrations. Moderately strong complexes were also found with the humic acids although in these cases it is likely that the complex contained more than one metal ion for each humate molecule. Similar stability constants were obtained for the humate acids and those with carboxylic acid complexes, suggesting that the dominant bonding sites in humics are the phthalate carboxylate sites.
Bibliographic Reference: EUR 14743 EN (1993) 82 pp., FS, ECU 11.50
ISBN: ISBN 92-826-6163-6
Record Number: 199311171 / Last updated on: 1994-11-29
Original language: en
Available languages: en