BESSRC-CAT bending magnet beamline at the advanced photon source

Beno, M. A.; Engbretson, M.; Jennings, G.; Knapp, G. S.; Linton, J.; Kurtz, C.; Rütt, U.; Montano, P. A.

doi:10.1016/s0168-9002(01)00465-x

Cited by 48 publications

(38 citation statements)

References 3 publications

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“…61,62 Plutonium L 3 -edge X-ray absorption data were acquired in the conventional 45/45°configuration with a 13-element fluorescence detector (without slits and filters) on bending magnet station 12-BM-B with a Rh focusing mirror and Si⟨111⟩ monochromator. 63 The incident X-ray energy was calibrated using Zr foil by setting the inflection point in the first differential XANES to 17.998 eV. The data in the XANES region were acquired at 0.8 eV/pt, between 18.027 and 18.102 keV, for the purpose of linear regression analysis and XANESfitting.…”

Section: ■ Experimental Methodsmentioning

confidence: 99%

Preparation, Stability, and Structural Characterization of Plutonium(VII) in Alkaline Aqueous Solution

et al. 2012

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A freshly prepared solution of Pu(VI) in 2 M NaOH was oxidized to Pu(VII), via ozonolysis, while simultaneously collecting X-ray absorption spectra. Analyses of the XANES (X-ray absorption near edge structure) and EXAFS (extended X-ray absorption fine structure) data, acquired throughout the in situ experiments, show a dioxo coordination environment for Pu(VI), PuO(2)(2+), typical for it and the hexavalent actinyl species of U and Np, and its evolution into a tetraoxo-coordination environment for Pu(VII), PuO(4)(-), like that known for Np(VII). The EXAFS data provide average Pu-O distances of 1.79(1) and 1.88(1) Å, respectively. The second coordination shells, also fit as O atoms, provide Pu-O distances of 2.29-2.32 Å that are independent of the Pu oxidation state. The coordination numbers for the distant O atoms in sums with those for the nearest O atoms are consistent with 6-O environments for both Pu(VI) and Pu(VII) ions in accordance with their previously proposed speciation as [Pu(VI)O(2)(OH)(4)](2-) and [Pu(VII)O(4)(OH)(2)](3-), respectively. This solution speciation accounts precisely for the Pu(VI) and Pu(VII) coordination environments reported in various solid state structures. The Pu(VII) tetraoxo-dihydroxo anion was found to have a half-life of 3.7 h. Its instability is attributed to spontaneous reduction to Pu(VI) and not to a measurable extent of disproportionation. We found no direct evidence for Pu(VIII) in the X-ray data and, furthermore, the stoichiometry of the oxidation of Cr(III) by Pu is consistent with that expected for a valence-pure Pu(VII) preparation by ozonation and, in turn, stoichiometrically equivalent to the established Np(VII)/Cr(III) redox reaction.

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Section: ■ Experimental Methodsmentioning

confidence: 99%

Preparation, Stability, and Structural Characterization of Plutonium(VII) in Alkaline Aqueous Solution

et al. 2012

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“…To characterize the clean sample surface, high resolution specular X-ray reflectivity data were collected at beamline 12-BM (BESSRC/XOR) at the Advanced Photon Source (APS), Argonne National Laboratory (ANL) (Beno et al, 2001a). The hematite sample was mounted in deionized water in a thin film cell sealed with 8 lm Kapton ä film on a four-circle diffractometer.…”

Section: X-ray Reflectivity Measurements and Analysismentioning

confidence: 99%

Bridging arsenate surface complexes on the hematite (012) surface

Catalano

Zhang

Park

et al. 2007

Geochimica et Cosmochimica Acta

105

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“…48 The energy bandwidth afforded by the beamline configuration was estimated to be 1 eV at the L 3 -edge energy, providing an instrumental resolution that is more than 4× smaller than the natural line width of 4.35 eV for the Er L 3 core hole. 49 Hence, the Er L 3 -edge XANES (X-ray absorption near edge structure) obtained here are negligibly broadened (≤3%) by the instrumental resolution function.…”

Section: ■ Experimental Methodsmentioning

confidence: 96%

Erbium(III) Coordination at the Surface of an Aqueous Electrolyte

Bera¹,

Luo²,

Schlossman

et al. 2015

J. Phys. Chem. B

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Grazing-incidence (GI) X-ray absorption spectroscopy (XAS) under conditions of total external reflection is used to explore the coordination environment of the trivalent erbium ion, Er(3+), at an electrolyte-vapor interface. A parallel study of the bulk aqueous electrolyte (1 M ErCl3 in HCl at pH = 1.54) shows that the Er(3+) ions have a simple hydration shell with an average Er-OH2 bond distance of 2.33(1) Å, consistent with previous descriptions of the aquated cation, [Er(OH2)8](3+). No other correlations are observed in the electrolyte EXAFS (extended X-ray absorption fine structure) data acquired at room temperature. In contrast, the coordination of the Er(3+) ions at the electrolyte-helium interface, as interrogated by use of electron-yield detection, reveal correlations beyond the Er-OH2 hydration shell that are unexpectedly well-defined. Analyses show an environment that consists of a first coordination sphere of 6-7 O atoms at 2.36(1) Å and a second one of 3 Cl atoms at 2.89(2) Å, suggesting the formation of a neutral [(H2O)6-7ErCl3] entity at the surface of the electrolyte. The presence of a third, distant peak in the Fourier transform data is attributed to Er-Er correlations (in possible combination with contributions from distant Er-O and Er-Cl interactions). The best-Z and -integer fits reveal 3 Er atoms at 3.20(2) Å, confirming the near-surface-enrichment of Er(3+) as revealed previously by use of X-ray reflectivity measurements (J. Phys. Chem. C 2013, 117, 19082). Here, the strong associations between the Er-aqua-chloro entities at the electrolyte-vapor interface are shown to be consistent with the formation of domains of polynuclear cluster motifs, such as would arise through hydrolysis reactions of the aquated Er(3+) cations. The local structural results and the calculated surface coverage are of relevance to understand the myriad reactions involved in the hydrometallurgical process of solvent extraction (SX) for metal purification, which involves the transfer of a selected metal ion, like Er, across an interface from an aqueous electrolyte to an organic phase.

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BESSRC-CAT bending magnet beamline at the advanced photon source

Cited by 48 publications

References 3 publications

Preparation, Stability, and Structural Characterization of Plutonium(VII) in Alkaline Aqueous Solution

Preparation, Stability, and Structural Characterization of Plutonium(VII) in Alkaline Aqueous Solution

Bridging arsenate surface complexes on the hematite (012) surface

Erbium(III) Coordination at the Surface of an Aqueous Electrolyte

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