Remediation and recovery of uranium from contaminated subsurface environments with electrodes
Remediation and recovery of uranium from contaminated subsurface environments with electrodes
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DOI：
10.1021/es050457e
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发表时间：
2005-11-15
影响因子：
11.4
通讯作者：
Lovley, DR
中科院分区：
文献类型：
--
作者：
Gregory, KB;Lovley, DR
以往的研究表明，锗种可以有效地去除污染地下水中的铀，通过还原可溶性U（VI）的相对不溶性的U（IV）与有机化合物作为电子供体。研究进行了，以确定是否电极可能作为一个替代的电子供体的U（VI）的还原由一个纯培养的Geetriumsulfreducens和微生物在铀污染的沉积物。在没有细胞的情况下，电极在-500 mV（相对于Ag/AgCl参比）下快速从溶液中去除U（VI）。然而，当电极处的泊被移除时，所有的U（VI）返回到溶液中，证明电极不还原U（VI）。如果G.当电极上存在硫还原剂时，U（VI）直到电极暴露于溶解氧才返回溶液。这表明G.电极上的硫还原剂将U（VI）还原为U（IV），U（IV）稳定沉淀，直到在氧气存在下再氧化。当电极被放置在铀污染的地下沉积物，U（VI）被删除，并从地下水中使用的电极恢复。在铀污染沉积物的流通柱中放置电极，可以很容易地从地下水中去除U（VI），在电极从沉积物中拔出后，87%的已去除的铀从电极表面回收。这些结果表明，微生物可以使用来自电极的电子来还原U（VI），并且有可能使用准备好的电极从受污染的地下水中去除和回收铀。
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/AgCI 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 suggests that 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.