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Uranyl Surface Complexes Formed on Subsurface Media from DOE Facilities
Author(s) -
Bostick Benjamin C.,
Fendorf Scott,
Barnett Mark O.,
Jardine Phillip M.,
Brooks Scott C.
Publication year - 2002
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2002.9900
Subject(s) - uranyl , sorption , ternary operation , chemistry , carbonate , aluminosilicate , phosphate , x ray absorption spectroscopy , chemical engineering , inorganic chemistry , absorption spectroscopy , organic chemistry , catalysis , adsorption , ion , physics , quantum mechanics , computer science , engineering , programming language
A mechanistic understanding of U sorption in natural soils and sediments is useful for determining its transport and bioavailability in the environment. X‐ray absorption spectroscopy (XAS) was used to determine the mechanisms by which U(VI) sorbs to three heterogeneous subsurface media reacted under static and dynamic flow conditions. Regardless of the media chosen, ternary surface complexes were the dominant type of sorption complex. Uranyl phosphate complexes were formed in subsurface media from more acidic environments. In contrast, uranyl carbonate ternary surface complexes formed in media from more neutral conditions. The complexes are predominantly inner‐sphere, although some outer‐sphere complexes may also be present, and appear to be on iron (hydr)oxides and possibly aluminosilicates. Additionally, the uranyl phosphate and carbonate complexes are highly disordered, which contributes to their reversible sorption properties.