4.5 Article

Investigation of diffusion and binding properties of uranium in the diffusive gradients in thin-films technique

Journal

ENVIRONMENTAL CHEMISTRY
Volume 19, Issue 4, Pages 263-273

Publisher

CSIRO PUBLISHING
DOI: 10.1071/EN22078

Keywords

binding; DGT; diffusion; in situ; kinetic; monitoring; speciation; uranium

Funding

  1. Fundamental Research Funds for the Central Universities [3132022158]

Ask authors/readers for more resources

This study demonstrated that the diffusion coefficient of uranium is independent of pH and the type of binding gel used, as long as the binding efficiency (B) is taken into account. These findings suggest that DGT equipped with either Metsorb or Chelex binding gels can accurately measure uranium under various environmental conditions.
Rationale Diffusive gradients in thin-films (DGT) ha been used for uranium speciation measurements since 2006, but interpretational difficulties have arisen due to uncertainties in the pH dependence of U diffusion coefficients (D) within the diffusive gel. This work tested the hypothesis that differences in measured D values between laboratories are due to methodological artifacts. Methodology The properties of uranium binding and diffusion of U within DGT were systematically investigated at different conditions between pH 3-8 and ionic strength from 1 to 500 mmol L-1. Previous uncertainties were attributed to loss of U by adsorption within the diffusion cell, identified by mass balance calculations, and a binding efficiency dependent on the type of binding gel. Results The diffusion coefficient in an agarose cross-linked polyacrylamide gel measured using Metsorb DGT of 5.26 +/- 0.17 x 10(-6) cm(2) s(-1) agreed well with both values obtained using a pre-conditioned diffusion cell (< 7% difference) and by modelling. The binding efficiencies for Chelex DGT (B-Chelex = 0.86-0.89) and Fe-oxide DGT (BFe-oxide = 0.64 were smaller than for Metsorb DGT (B-Metsorb = 1). No significant differences were found for B-Chelex at different pH. Discussion This work demonstrated that the diffusion coefficient of uranium is independent of pH and the binding gel used, provided the binding efficiency (B) is taken into account. These findings indicate that DGT equipped with either Metsorb or Chelex binding gels should be capable of measuring U for a wide range of environmental conditions provided the appropriate diffusion coefficients and binding efficiencies are used.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.5
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available