Application of High-Energy-Resolution X-ray Absorption Spectroscopy at the U M edge to Assess U(V) Electronic Structure in U on magnetite/ma

The oxidation state of uranium (U) largely controls its migration behavior in the environment. Recent studies have evidence the importance of minor chemical species of U(V), especially when interacting with minerals such as magnetite. There was little knowledge of the exact mechanism involved in U(V) sorption to magnetite. Indeed, magnetite stoichiometry (R = Fe(II)/Fe(III)) is rarely controlled or monitored in U-magnetite interaction studies, although it was shown to affect not only redox transformation but also adsorption mechanisms of several contaminants. This study examined the interaction of U with 10 nm-sized magnetites, whose stoichiometries were carefully defined (0.1 ≤ R ≤ 0.5) and preserved in anaerobic conditions. We will conduct HERFD-XANES analysis at the U M-edge to clarify the spectral differences between U(V) on stoichiometries of magnetites, which will help understand the U adsorption mechanism on magnetite and predict the fate and transport of U in environment.