Incorporation of uranium into hematite during crystallization from ferrihydrite

Timothy A. Marshall, Katherine Morris, Gareth T W Law, Francis R. Livens, J. Frederick W Mosselmans, Pieter Bots, Samuel Shaw

    Research output: Contribution to journalArticlepeer-review


    Ferrihydrite was exposed to U(VI)-containing cement leachate (pH 10.5) and aged to induce crystallization of hematite. A combination of chemical extractions, TEM, and XAS techniques provided the first evidence that adsorbed U(VI) (≈3000 ppm) was incorporated into hematite during ferrihydrite aggregation and the early stages of crystallization, with continued uptake occurring during hematite ripening. Analysis of EXAFS and XANES data indicated that the U(VI) was incorporated into a distorted, octahedrally coordinated site replacing Fe(III). Fitting of the EXAFS showed the uranyl bonds lengthened from 1.81 to 1.87 Å, in contrast to previous studies that have suggested that the uranyl bond is lost altogether upon incorporation into hematite the results of this study both provide a new mechanistic understanding of uranium incorporation into hematite and define the nature of the bonding environment of uranium within the mineral structure. Immobilization of U(VI) by incorporation into hematite has clear and important implications for limiting uranium migration in natural and engineered environments. © 2014 American Chemical Society.
    Original languageEnglish
    Pages (from-to)3724-3731
    Number of pages7
    JournalEnvironmental Science and Technology
    Issue number7
    Publication statusPublished - 1 Apr 2014


    Dive into the research topics of 'Incorporation of uranium into hematite during crystallization from ferrihydrite'. Together they form a unique fingerprint.

    Cite this