Fate of Adsorbed U(VI) during Sulfidization of Lepidocrocite and Hematite.

ABSTRACT: The impact on U(VI) adsorbed to lepidocrocite (γ-FeOOH) and hematite (α-Fe₂O₃) was assessed when exposed to aqueous sulfide (S(-II)_aq) at pH 8.0. With both minerals, competition between S(-II) and U(VI) for surface sites caused instantaneous release of adsorbed U(VI). Compared to lepidocrocite, consumption of S(-II)_aq proceeded slower with hematite, but yielded maximum dissolved U concentrations that were more than 10 times higher, representing about one-third of the initially adsorbed U. Prolonged presence of S(-II)_aq in experiments with hematite in combination with a larger release of adsorbed U(VI), enhanced the reduction of U(VI): after 24 h of reaction about 60-70% of U was in the form of U(IV), much higher than the 25% detected i

SUBMITTER: Alexandratos VG 

PROVIDER: S-EPMC5343554 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature