Gregory, K. B. & Lovley, D. R. Remediation and recovery of uranium from contaminated subsurface environments with electrodes. Environ. Sci. Technol. 39, 8943-8947

Department of Microbiology, University of Massachusetts, 203 Morrill 4 North, Amherst, Massachusetts 01003, USA.
Environmental Science and Technology (Impact Factor: 5.33). 12/2005; 39(22):8943-7. DOI: 10.1021/es050457e
Source: PubMed


Previous studies have demonstrated that Geobacter species can effectively remove uranium from contaminated groundwater by reducing soluble U(VI) to the relatively insoluble U(IV) with organic compounds serving as the electron donor. Studies were conducted to determine whether electrodes might serve as an alternative electron donor for U(VI) reduction by a pure culture of Geobacter sulfurreducens and microorganisms in uranium-contaminated sediments. Electrodes poised at -500 mV (vs a Ag/AgCl reference) rapidly removed U(VI) from solution in the absence of cells. However, when the poise at the electrode was removed, all of the U(VI) returned to solution, demonstrating that the electrode did not reduce U(VI). If G. sulfurreducens was present on the electrode, U(VI) did not return to solution until the electrode was exposed to dissolved oxygen. This suggeststhat G. sulfurreducens on the electrode reduced U(VI) to U(IV) which was stably precipitated until reoxidized in the presence of oxygen. When an electrode was placed in uranium-contaminated subsurface sediments, U(VI) was removed and recovered from groundwater using poised electrodes. Electrodes emplaced in flow-through columns of uranium-contaminated sediments readily removed U(VI) from the groundwater, and 87% of the uranium that had been removed was recovered from the electrode surface after the electrode was pulled from the sediments. These results suggest that microorganisms can use electrons derived from electrodes to reduce U(VI) and that it may be possible to remove and recover uranium from contaminated groundwater with poised electrodes.

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Available from: Kelvin B Gregory, Jan 21, 2015
    • "For example, as direct electron donors to bacterial cells or the in-situ production of electron donors such as H 2 . Furthermore, diffusion of metal ions to bacterial cells immolated on electrodes could be improved by capacitive deionisation[64]. Finally, acid functional groups or cell wall enzymes implicated in metal sorption and reduction could be influenced by applied potential. "
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    • "Reduction of uranium using several materials has been well investigated: (1) Nano-sized zero-valent iron (nZVI) (Fiedor et al. 1998, Noubactep et al. 2006, Riba et al. 2008); (2) electrodes (Gregory and Derek 2005); (3) sulfide minerals (Wersin et al. 1994); and (4) iron-bearing soil minerals (Kriegman-King and Reinhard 1994, Butler and Hayes 1998, Lee and Batchelor 2002, Kim and Batchelor 2009, Descostes et al. 2010). Iron-bearing soil minerals such as vivianite, maghemite, and green rust showed high reductive capacity to reduce toxic chemicals including radioactive compounds (Lee et al. 2000, Zachara et al. 2001, Roden et al. 2002, Jung et al. 2012). "

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