Kinetic study of uranium speciation in model solutions and in natural waters using Competitive Ligand Exchange Method

Jiujiang Zhao, Ismail I. Fasfous, John D. Murimboh, Tahir Yapici, Parthasarathi Chakraborty, Sheren Boca, Chuni L. Chakrabarti*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

Kinetic speciation of uranium in model solutions containing uranium and humic acid (HA) and in natural waters has been investigated by Competitive Ligand Exchange Method (CLEM). In alkaline freshwaters, most of uranium species were uranium-carbonate species, which were labile in the CLEM experiment. The uranium speciation of every sample was characterized either as "labile" or "non-labile" uranium complexes depending on the dissociation rate coefficients of the complexes. The results showed that as the U(VI)/HA ratio was decreased, the dissociation rate coefficients decreased and the labile fraction decreased as well. When the U(VI)/HA ratio was 0.1, the labile fraction of the U(VI)-HA increased with increasing pH; however, there was no pH effect on the dissociation of U(VI)-HA complexes at lower U(VI)/HA ratios. Chelex-100 had some limitations in its use for the study of dissociation of U(VI)-HA complex at very low U(VI)/HA ratios. By developing an analytical method and procedure for quantitative determination of kinetic parameters for the dissociation of uranium-HA complexes in model solutions and natural waters, this work has made a substantial contribution to analytical chemistry.

Original languageEnglish (US)
Pages (from-to)1015-1020
Number of pages6
JournalTalanta
Volume77
Issue number3
DOIs
StatePublished - Jan 15 2009
Externally publishedYes

Keywords

  • Competitive Ligand Exchange Method
  • Humic acid
  • ICP-MS
  • Natural waters
  • Speciation
  • Uranium

ASJC Scopus subject areas

  • Analytical Chemistry

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