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N. A. Wall, M. Borkowski, J. Chen, Gregory R. Choppin

Complexation of americium with humic, fulvic and citric acids at high ionic strength

The stability constants of the Am³⁺ complexes of humic, fulvic and citric acids (HA, FA and Cit) were determined as a function of ionic strength (NaCl) using a solvent extraction technique. At a HA degree of ionization of 0.7 for the carboxylate groups, the Am-HA binding constant, logβ₁, varies from 8.3 at I=0.2 m to 7.2 at I=6.0 m. The logβ₁ of Am-Cit varies from 5.9 at I=0.3 m to 5.10 at I=5.0 m. Comparison of the binding constants of Am with HA, FA and Cit shows that, at high ionic strength, logβ₁(AmCit)≈logβ₁(AmFA)≈logβ₁AmHA-1. Comparison of the values of other metals indicate that the logβ₁ values for Cit can serve to estimate HA and FA.

Radiochimica Acta, Oldenbourg Wissenschaftsverlag

Print ISSN: 0033-8230
Volume: 90, 09/2002
Pages: 563

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