title: Mica surfaces stabilize pentavalent uranium.
abstract: High-resolution X-ray photoelectron spectroscopy was used to demonstrate that reduction of aqueous U6+ at ferrous mica surfaces at 25 degrees C preserves U5+ as the dominant sorbed species over a broad range of solution compositions. Polymerization of sorbed U5+ with sorbed U6+ and U4+ is identified as a possible mechanism for how mineral surfaces circumvent the rapid disproportionation of aqueous U5+. The general nature of this mechanism suggests that U5+ could play an important, but previously unidentified, role in the low-temperature chemistry of uranium in reducing, heterogeneous aqueous systems.
authors.affiliation: Pacific Northwest National Laboratory, Chemical Science Division, MSIN: K8-96, 902 Battelle Boulevard, Richland, Washington 99352, USA. Eugene.Ilton@pnl.gov
authors.forename: Eugene S
authors.initials: ES
authors.lastname: Ilton
authors.forename: Anca
authors.initials: A
authors.lastname: Haiduc
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Cahill
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Felmy