Influence of Dynamical Conditions on the Reduction of UVI at the Magnetite-Solution Interface

Journal Article · Thu Jan 14 04:00:00 EST 2010 · Environmental Science & Technology, 44(1):170-176

DOI:https://doi.org/10.1021/es9014597· OSTI ID:974920

Ilton, Eugene S; Boily, Jean F; Buck, Edgar C; Skomurski, Frances N; Rosso, Kevin M; Cahill, Christopher L; Bargar, John R; Felmy, Andrew R

The heterogeneous reduction of UVI to UIV by ferrous iron is a potentially key process influencing the fate and transport of U in the environment. The reactivity of both sorbed and structural FeII has been studied for numerous substrates, including magnetite. The results from UVI-magnetite experiments have been variable, ranging from no reduction to clear evidence for the formation of UIV. In this contribution, we used XAS and high resolution (+cryogenic) XPS to study the interaction of UVI with nano-particulate magnetite. The results indicated that UVI was partially reduced to UV with no evidence of UIV. However, thermodynamic calculations indicated that mixed-valence U phases with average oxidation states below (V) should have been stable, indicating that the system was not in redox equilibrium. A reaction pathway that involves incorporation of U and stabilization of UV and UVI in secondary phases is invoked to explain the observations.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 974920
• Report Number(s): PNNL-SA-66737; 19823; KC0303020
• Journal Information: Environmental Science & Technology, 44(1):170-176, Journal Name: Environmental Science & Technology, 44(1):170-176
• Country of Publication: United States
• Language: English

Related Subjects

Environmental Molecular Sciences Laboratory
magnetite
pentavalent uranium
reduction