A model-based evaluation of sorptive reactivities of hydrous ferric oxide and hematite for U(VI)

Je Hun Jang, Brian A. Dempsey, William D. Burgos

Research output: Contribution to journalArticle

52 Scopus citations

Abstract

The sorption of uranyl onto hydrous ferric oxide (HFO) or hematite was measured by discontinuously titrating the suspensions with uranyl at pH 5.9, 6.8, and 7.8 under PCO2 = 10-3.5atm (sorption isotherms). Batch reactors were used with equilibration times up to 48 days. Sorption of 1 μM uranyl onto HFO was also measured versus pH (sorption edge). A diffuse double layer surface complexation model was calibrated by invoking three sorption species that were consistent with spectroscopic evidence for predominance of bidentate complexes at neutral pH and uranyl-carbonato complexes: >SOH:UO2OH+ (>SO)2: UO 2CO3-2, and (>SO)2:(UO 2)3(OH)5-1. The model was consistent with previously published isotherm and edge data. The model successfully predicted sorption data onto hematite, only adjusting for different measured specific surface area. Success in application of the model to hematite indicates that the hydrated surface of hematite has similar sorptive reactivity as HFO.

Original languageEnglish (US)
Pages (from-to)4305-4310
Number of pages6
JournalEnvironmental Science and Technology
Volume41
Issue number12
DOIs
StatePublished - Jun 15 2007

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry

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