Abstract
The sorption behaviour of uranium(VI) and selenium(IV) on a purified bentonite sample has been investigated and the results compared with those for sorption onto the unpurified material and goethite. Batch sorption data for U(VI) on purified bentonite show strong sorption in the pH range 5 to 8 (R(d)>104 cm3 g-1). Outside this range the sorption decreases although the R(d) remains above 103 cm3 g-1 across the pH range studied. U(VI) sorption was also found to decrease rapidly with increasing carbonate concentration. Thermodynamic modelling of the data indicates that sorption at low pH may be due to an ion-exchange process, whereas above pH 5 surface complexation dominates. The sorption of Se(IV) on purified bentonite was found to be significant only below pH 7. Sorption of Se(IV) on goethite showed a strong dependency on pH; with strong sorption below pH 8, and a sharp decrease in sorption above pH 8. Sorption of Se(IV) onto the smectite component of impure bentonite is therefore only likely to be significant at low pH and sorption is dominated by a goethite-like surface of an iron constituent mineral above pH 5. Copyright (C) 1998 Elsevier Science B.V.
Original language | English |
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Pages (from-to) | 141-150 |
Number of pages | 10 |
Journal | Journal of Contaminant Hydrology |
Volume | 35 |
Issue number | 1-3 |
DOIs | |
Publication status | Published - Dec 15 1998 |
Externally published | Yes |
Event | Proceedings of the 1997 6th International Conference on the Chemistry and Migration Behavior of Actinides and Fission Products in the Geosphere - Sendai, Jpn Duration: Oct 26 1997 → Oct 31 1997 |
Keywords
- Bentonite
- Montmorillonite
- Radionuclides
- Selenium
- Sorption
- Uranium
ASJC Scopus subject areas
- Environmental Chemistry
- Water Science and Technology