Structural environment of uranium (VI) species sorbed onto ZrP2O7: X-ray absorption spectroscopy study

Drot, R.; Simoni, E.; Denauwer, Christophe

doi:10.1016/s1387-1609(99)80010-3

Cited by 8 publications

(13 citation statements)

References 27 publications

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“…As the uranyl ions get closer to the surface, coordination water molecules are removed. This result is in agreement with previous ones found for the U(VI)/ZrP 2 O 7 system [13]. …”

Section: Spectroscopic Characterizationsupporting

confidence: 94%

See 1 more Smart Citation

Surface complexation modeling of uranium(VI) sorbed onto zirconium oxophosphate versus temperature: Thermodynamic and structural approaches

Almazán-Torres

Drot

Mercier‐Bion

et al. 2008

Journal of Colloid and Interface Science

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“…As the uranyl ions get closer to the surface, coordination water molecules are removed. This result is in agreement with previous ones found for the U(VI)/ZrP 2 O 7 system [13]. …”

Section: Spectroscopic Characterizationsupporting

confidence: 94%

“…Moreover, in solution this ion is known to easily form strong complexes with phosphate ligands. This property has been already observed with the uranyl ions in contact with phosphate minerals as well [11][12][13].…”

Section: Introductionsupporting

confidence: 67%

Surface complexation modeling of uranium(VI) sorbed onto zirconium oxophosphate versus temperature: Thermodynamic and structural approaches

Almazán-Torres

Drot

Mercier‐Bion

et al. 2008

Journal of Colloid and Interface Science

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“…Structural studies carried out using X-ray photoelectron spectroscopy (XPS), optical spectroscopy, and extended X-ray absorption fine structure (EXAFS) have been previously reported. , Nevertheless, we will reiterate the main results in order to lead to an easy understanding of our general sorption processes approach. Then, this structural information will be used as experimental constraints for the fitting procedure of the experimental data (using FITEQLv3.2), which allows one to determine the sorption constant values of U(VI) and Eu(III) ions sorbed onto Th 4 (PO 4 ) 4 P 2 O 7 , Zr 2 O(PO 4 ) 2 , and ZrP 2 O 7 .…”

Section: Introductionmentioning

confidence: 92%

“…(iv) EXAFS experiments have shown that the uranyl and europium species are sorbed as bidentate inner-sphere complexes …”

Section: State Of the Artmentioning

confidence: 99%

Uranium(VI) and Europium(III) Speciation at the Phosphate Compounds−Solution Interface

Drot

Simoni

1999

Langmuir

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Prediction of radionuclides migration through a geosphere is of fundamental interest in order to evaluate the safety of an underground radwastes repository. We have studied uranyl and europium(III) ion sorption mechanisms onto three phosphate compounds: ZrP2O7, Zr2O(PO4)2, and Th4(PO4)4P2O7. A spectroscopic investigation which has been previously reported has allowed one to determine all species involved in the sorption processes under study. This paper presents the modeling of experimental retention data using FITEQLv3.2 code (constant capacitance model). All sorption isotherms were successfully simulated with respect to the structural constraints. We have shown that uranyl sorption onto the solids under study is less influenced by electrostatic interactions between aqueous species and charges on the surface than is that for europium(III) ion. Because many experimental constraints, obtained from independent spectroscopic techniques, have been taken into account for the fitting procedure, the sorption constant values can be determined accurately.

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“…Extensive laboratory experiments have been conducted on the uptake of U from aqueous solutions by crystalline and amorphous Zr-(oxyhydr)oxides and Zr-phosphates (e.g., Amphlett, 1964;Gal and Ruvarac, 1964;Horwitz, 1966;Vesely et al, 1968;Ruvarac and Vesely, 1970;Marei et al, 1972;Aly et al, 1975;Pakholkov and Zelenin, 1988;Song et al, 1995;Plotnikov and Bannykh, 1997;Drot et al, 1999;Zhuravlev et al, 2002;Lomenech et al, 2003;Misaelides et al, 2006;Um et al, 2007;Finck et al, 2008). Early studies focused on the use of these materials as industrial ion exchangers, while more recent ones were designed to test their applicability to the remediation or prevention of U contamination in soils and natural waters.…”

Section: Zr-rich Materialsmentioning

confidence: 99%

Newly recognized hosts for uranium in the Hanford Site vadose zone

Stubbs

Veblen

Elbert

et al. 2009

Geochimica et Cosmochimica Acta

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Uranium contaminated sediments from the U.S. Department of Energy's Hanford Site have been investigated using electron microscopy. Six classes of solid hosts for uranium were identified. Preliminary sediment characterization was carried out using optical petrography, and electron microprobe analysis (EMPA) was used to locate materials that host uranium. All of the hosts are fine-grained and intergrown with other materials at spatial scales smaller than the analytical volume of the electron microprobe. A focused ion beam (FIB) was used to prepare electron-transparent specimens of each host for the transmission electron microscope (TEM). The hosts were identified as: (1) metatorbernite [Cu(UO 2 ) 2 (PO 4 ) 2 Á8H 2 O]; (2) coatings on sediment clasts comprised mainly of phyllosilicates; (3) an amorphous zirconium (oxyhydr)oxide found in clast coatings; (4) amorphous and poorly crystalline materials that line voids within basalt lithic fragments; (5) amorphous palagonite surrounding fragments of basaltic glass; and (6) Fe-and Mn-oxides. These findings demonstrate the effectiveness of combining EMPA, FIB, and TEM to identify solid-phase contaminant hosts. Furthermore, they highlight the complexity of U geochemistry in the Hanford vadose zone, and illustrate the importance of microscopic transport in controlling the fate of contaminant metals in the environment.

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Structural environment of uranium (VI) species sorbed onto ZrP2O7: X-ray absorption spectroscopy study

Cited by 8 publications

References 27 publications

Surface complexation modeling of uranium(VI) sorbed onto zirconium oxophosphate versus temperature: Thermodynamic and structural approaches

Surface complexation modeling of uranium(VI) sorbed onto zirconium oxophosphate versus temperature: Thermodynamic and structural approaches

Uranium(VI) and Europium(III) Speciation at the Phosphate Compounds−Solution Interface

Newly recognized hosts for uranium in the Hanford Site vadose zone

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