The Local Uranium Environment in Cesium Uranates: A Combined XPS, XAS, XRD, and Neutron Diffraction Analysis

Berghe, S. Van den; Verwerft, Marc; Laval, J.P.; Gaudreau, B.; Allen, P. G.; Wyngarden, A. Van

doi:10.1006/jssc.2002.9594

Cited by 57 publications

(47 citation statements)

References 29 publications

(36 reference statements)

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“…In this case, the role of the ligand field splitting for the broadening of the L 3 edge (2p 3/2 ) XAS peak was shown to dominate over the unresolved multiplet splittings. Interestingly, the UO 3 L 3 XANES spectrum is significantly different than that of the UO 2 L 3 XANES [9,40]. In fact, there is a shoulder present at about 10 eV above the main white line in γ-UO 3 , possibly corresponding to the 7 eV separation described above for the δ-UO 3 6d…”

Section: Oxidation and Crystal Field Effects In Uraniummentioning

confidence: 80%

Oxidation and crystal field effects in uranium

Tobin

Booth

et al. 2015

Phys. Rev. B

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An extensive investigation of oxidation in uranium has been pursued. This includes the utilization of soft X-ray Absorption Spectroscopy (XAS), hard X-ray Absorption Near Edge Structure (XANES), Resonant (hard) X-ray Emission Spectroscopy (RXES), Cluster Calculations and a Branching Ratio analysis founded on Atomic Theory. The samples utilized were uranium dioxide (UO 2 ), uranium trioxide (UO 3 ) and uranium tetrafluoride (UF 4 ). A discussion of the role of non-spherical perturbations, i.e. crystal or ligand field effects, will be presented.

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Section: Oxidation and Crystal Field Effects In Uraniummentioning

confidence: 80%

Oxidation and crystal field effects in uranium

Tobin

Booth

et al. 2015

Phys. Rev. B

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“…uranate species are shifted to higher energies compared to uranyl species as shown in (Duff et al, 2002;Van den Berghe et al, 2002;Belai et al, 2008). The po-mag#42 WL broadening, asymmetric shape and its energy position indicate the presence of mixtures of U oxidation states.…”

Section: Xasmentioning

confidence: 93%

U(VI) removal kinetics in presence of synthetic magnetite nanoparticles

Huber

Schild

Vitova

et al. 2012

Geochimica et Cosmochimica Acta

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“…3) that was absent in the sorption samples. This has been attributed to U(V) or U(VI) in octahedral uranate coordination (Van den Berghe et al, 2002;Soldatov et al, 2007). Therefore, both the partial shift to lower absorption edge energy, and the shoulder feature in the coprecipitation experiments suggest that U(V) may be present within the samples with uranatelike coordination.…”

Section: X-ray Absorption Spectroscopymentioning

confidence: 96%

Uranium fate during crystallization of magnetite from ferrihydrite in conditions relevant to the disposal of radioactive waste

et al. 2015

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Uranium incorporation into magnetite and its behaviour during subsequent oxidation has been investigated at high pH to determine the uranium retention mechanism(s) on formation and oxidative perturbation of magnetite in systems relevant to radioactive waste disposal. Ferrihydrite was exposed to U(VI) aq containing cement leachates ( pH 10.5-13.1) and crystallization of magnetite was induced via addition of Fe(II) aq . A combination of XRD, chemical extraction and XAS techniques provided direct evidence that U(VI) was reduced and incorporated into the magnetite structure, possibly as U(V), with a significant fraction recalcitrant to oxidative remobilization. Immobilization of U(VI) by reduction and incorporation into magnetite at high pH, and with significant stability upon reoxidation, has clear and important implications for limiting uranium migration in geological disposal of radioactive wastes.

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The Local Uranium Environment in Cesium Uranates: A Combined XPS, XAS, XRD, and Neutron Diffraction Analysis

Cited by 57 publications

References 29 publications

Oxidation and crystal field effects in uranium

Oxidation and crystal field effects in uranium

U(VI) removal kinetics in presence of synthetic magnetite nanoparticles

Uranium fate during crystallization of magnetite from ferrihydrite in conditions relevant to the disposal of radioactive waste

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