Reductive precipitation of uranium(VI) by zero-valent iron
- Oak Ridge National Lab., TN (United States)
- Univ. of Wales, Cardiff (United Kingdom). Dept. of Earth Sciences
This study was undertaken to determine the effectiveness of zero-valent iron (Fe{sup 0}) and several adsorbent materials in removing uranium (U) from contaminated groundwater and to investigate the rates and mechanisms that are involved in the reactions. Fe{sup 0} filings were used as reductants, and the adsorbents included peat materials, iron oxides, and a carbon-based sorbent (Cercona Bone-Char). Results indicate that Fe{sup 0} filings are much more effective than the adsorbents in removing uranyl (UO{sub 2}{sup 2+}) from the aqueous solution. Nearly 100% of U was removed through reactions with Fe{sup 0} at an initial concentration up to 76 mM. Results from the batch adsorption and desorption and from spectroscopic studies indicate that reductive precipitation of U on Fe{sup 0} is the major reaction pathway. Only a small percentage of UO{sub 2}{sup 2+} appeared to be adsorbed on the corrosion products of Fe{sup 0} and could be desorbed by leaching with a carbonate solution. The study also showed that the reduced U(IV) species on Fe{sup 0} surfaces could be reoxidized and potentially remobilized when the reduced system becomes more oxidized. Results of this research support the application of the permeable reactive barrier technology using Fe{sup 0} as a reactive media to intercept U and other groundwater contaminants migrating to the tributaries of Bear Creek at the US Department of Energy`s Y-12 Plant located in Oak Ridge, TN.
- Sponsoring Organization:
- USDOE Office of Environmental Restoration and Waste Management, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 323754
- Journal Information:
- Environmental Science and Technology, Vol. 32, Issue 21; Other Information: PBD: 1 Nov 1998
- Country of Publication:
- United States
- Language:
- English
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