Journal
SCIENCE OF THE TOTAL ENVIRONMENT
Volume 643, Issue -, Pages 260-269Publisher
ELSEVIER
DOI: 10.1016/j.scitotenv.2018.06.162
Keywords
Radionuclide sorption; Colloid concentration; Uranium ternary species; Ionic strength; Competitive sorption
Categories
Funding
- Israeli Atomic Energy Agency, PAZI [287/17]
- Israel Science Foundation [165/17]
- Israeli Ministry of Adsorption
- Kreitman School of Advanced Studies of Ben-Gurion University of the Negev
- Rieger Foundation
Ask authors/readers for more resources
In the context of geological disposal of radioactive waste, one of the controlling mechanisms for radionuclide migration through subsurface strata is sorption to mobile colloidal bentonite particles. Such particles may erode from the repository backfill or bentonite buffer and yield measurable (0.01-0.1 g/L) concentrations in natural groundwater. The extent of sorption is influenced by colloid concentration, ionic strength, radionuclide concentration, and the presence of competing metals. Uranium(VI) and cesium sorption to bentonite colloids was investigated both separately and together in low ionic strength (2.20 mM) artificial rainwater (ARW) and high ionic strength (169 mM) artificial groundwater (AGW; representative of a fractured carbonate rock aquitard). Sorption experiments were conducted as a factor of colloid concentration, initial metal concentration and opposing metal presence. It was shown that both U(VI) and Cs sorption were significantly reduced in AGW in comparison to ARW. Additionally, the sorption coefficient K-d of both metals was found to decrease with increasing colloid concentration. Competitive sorption experiments indicated that at high colloid concentration (1-2 g/L), Cs sorption was reduced in the presence of U(VI), and at low colloid concentration (0.01-0.5 g/L), both Cs and U(VI) K(d)s were reduced when they were present together due to competition for similar sorption sites. The results from this study imply that in brackish carbonate rock aquifers, typical of the Israeli northern Negev Desert, both U(VI) and Cs are more likely to be mobile as dissolved species rather than as colloid-associated solids. (C) 2018 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available