ANSTO Publications Online >
Journal Publications >
Journal Articles >

Please use this identifier to cite or link to this item: http://apo.ansto.gov.au/dspace/handle/10238/3162

Title: Effect of amorphous Fe(III) oxide transformation on the Fe(II)-mediated reduction of U(VI).
Authors: Boland, DD
Collins, RN
Payne, TE
Waite, TD
Keywords: Crystallization
Goethite
Magnetite
Uranium
Absorption Spectroscopy
Silicates
Issue Date: 15-Feb-2011
Publisher: American Chemical Society
Citation: Boland, D. D., Collins, R. N., Payne, T. E., & Waite, T. D. (2011). Effect of amorphous Fe(III) oxide transformation on the Fe(II)-mediated reduction of U(VI). Environmental Science & Technology, 45(4), 1327-1333.
Abstract: It has recently been reported that the Fe(II)-catalyzed crystallization of 2-line ferrihydrite to goethite and magnetite can result in the immobilization of uranium. Although it might be expected that interference of the crystallization process (for example, by the presence of silicate) would prevent uranium immobilization, this has not yet been demonstrated. Here we present results of an X-ray absorption spectroscopy study on the fate of hexavalent uranium (U(VI)) during the Fe(II)-catalyzed transformations of 2-line ferrihydrite and ferrihydrite coprecipitated with silicate (silicate−ferrihydrite). Two-line ferrihydrite transformed monotonically to goethite, whereas silicate−ferrihydrite transformed into a form similar to ferrihydrite synthesized in the absence of silicate. Modeling of U L(III)-edge EXAFS data indicated that both coprecipitated and adsorbed U(VI) were initially associated with ferrihydrite and silicate−ferrihydrite as a mononuclear bidentate surface complex. During the Fe(II)-catalyzed transformation process, U(VI) associated with 2-line ferrihydrite was reduced and partially incorporated into the newly formed goethite mineral structure, most likely as U(V), whereas U(VI) associated with silicate−ferrihydrite was not reduced and remained in a form similar to its initially adsorbed state. Uranium(VI) that was initially adsorbed to silicate−ferrihydrite did, however, become more resistant to reductive dissolution indicating at least a partial reduction in mobility. These results suggest that when the Fe(II)-catalyzed transformation of ferrihydrite-like iron oxyhydroxides is inhibited, at least under conditions similar to those used in these experiments, uranium reduction will not occur. © 2011, American Chemical Society
URI: http://dx.doi.org/10.1021/es101848a
http://apo.ansto.gov.au/dspace/handle/10238/3162
ISSN: 0013-936X
Appears in Collections:Journal Articles

Files in This Item:

There are no files associated with this item.

Items in APO are protected by copyright, with all rights reserved, unless otherwise indicated.

 

Valid XHTML 1.0! DSpace Software Copyright © 2002-2010  Duraspace - Feedback