biostudies-literatureAlexandratos VGSeventh Framework Programme2140-2150https://www.ebi.ac.uk/biostudies/studies/S-EPMC5343554biostudies-literatureUnknown51(4)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 iEnvironmental science & technologyFate of Adsorbed U(VI) during Sulfidization of Lepidocrocite and Hematite.PMC5343554212287Alexandratos VGVan Cappellen PBehrends TfalseFate of Adsorbed U(VI) during Sulfidization of Lepidocrocite and Hematite.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 i2017-01-01T00:00:00Z2017 Feb2025-04-04T14:32:52.806Z2019-03-27T02:38:16ZS-EPMC53435542812113710.1021/acs.est.6b05453