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Neill T, Morris K, Pearce CI, Sherriff NK, Bryan N, Rigby B, Shaw S. Sorption of Strontium to Uraninite and Uranium(IV)-Silicate Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:3090-3097. [PMID: 35226492 PMCID: PMC9098169 DOI: 10.1021/acs.langmuir.1c02927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/06/2022] [Indexed: 06/14/2023]
Abstract
Spent nuclear fuel contains both uranium (U) and high yield fission products, including strontium-90 (90Sr), a key radioactive contaminant at nuclear facilities. Both U and 90Sr will be present where spent nuclear fuel has been processed, including in storage ponds and tanks. However, the interactions between Sr and U phases under ambient conditions are not well understood. Over a pH range of 4-14, we investigate Sr sorption behavior in contact with two nuclear fuel cycle relevant U(IV) phases: nano-uraninite (UO2) and U(IV)-silicate nanoparticles. Nano-UO2 is a product of the anaerobic corrosion of metallic uranium fuel, and UO2 is also the predominant form of U in ceramic fuels. U(IV)-silicates form stable colloids under the neutral to alkaline pH conditions highly relevant to nuclear fuel storage ponds and geodisposal scenarios. In sorption experiments, Sr had the highest affinity for UO2, although significant Sr sorption also occurred to U(IV)-silicate phases at pH ≥ 6. Extended X-ray absorption fine structure (EXAFS) spectroscopy, transmission electron microscopy, and desorption data for the UO2 system suggested that Sr interacted with UO2 via a near surface, highly coordinated complex at pH ≥ 10. EXAFS measurements for the U(IV)-silicate samples showed outer-sphere Sr sorption dominated at acidic and near-neutral pH with intrinsic Sr-silicates forming at pH ≥ 12. These complex interactions of Sr with important U(IV) phases highlight a largely unrecognized control on 90Sr mobility in environments of relevance to spent nuclear fuel management and storage.
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Affiliation(s)
- Thomas
S. Neill
- Research
Centre for Radwaste Disposal and Williamson Research Centre, School
of Earth & Environmental Sciences, The
University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Katherine Morris
- Research
Centre for Radwaste Disposal and Williamson Research Centre, School
of Earth & Environmental Sciences, The
University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Carolyn I. Pearce
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - Nicholas K. Sherriff
- National
Nuclear Laboratory, Chadwick
House, Warrington Road, Birchwood Park, Warrington WA3 6AE, U.K.
| | - Nick Bryan
- National
Nuclear Laboratory, Chadwick
House, Warrington Road, Birchwood Park, Warrington WA3 6AE, U.K.
| | - Bruce Rigby
- Sellafield
Ltd., Hinton House, Birchwood Park Avenue, Risley, Warrington, Cheshire WA3
6GR, U.K.
| | - Samuel Shaw
- Research
Centre for Radwaste Disposal and Williamson Research Centre, School
of Earth & Environmental Sciences, The
University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
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Phatak R, Gupta SK, Maheshwari P, Das A, Sali SK. Crystal structure of Ba 2(La 0.727Ba 0.182M 0.091)MO 6 (M = Nb, Sb, Bi): symmetry nuance identified in photoluminescence and IR spectroscopy studies. Dalton Trans 2017; 46:1694-1703. [PMID: 28102388 DOI: 10.1039/c6dt04124h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A one-third lanthanum deficiency was created in Ba2LaM5+O6 compounds (LaM compounds) to form Ba2La2/3M5+O5.5 compounds (La2/3M compounds) for M = Nb, Sb, and Bi. The compounds were prepared by a gel-combustion method using citric acid as a fuel. All the compounds were characterized by powder X-ray diffraction (XRD). The XRD analysis showed that the space group of the La2/3M compounds remains the same for the Bi and Sb samples when compared to the reported LaM compounds, except for the Nb sample. La2/3Nb and La2/3Sb adopt a rhombohedral structure with the space group R3[combining macron], whereas La2/3Bi adopts a monoclinic structure with the space group I2/m. As the positron annihilation spectroscopy (PALS) technique is sensitive to cation deficiency, it was used to detect the presence of cation vacancies in the samples, which are formed due to the decrease in the lanthanum concentration. The PALS analyses indicated that the absence of cation deficiency in the La2/3M compounds is similar to that observed in the LaM compound. Thus, the crystal structure of the La2/3M compound was modeled, such that the cation deficiency at the La site is filled by Ba2+ and M5+ ions, and the crystal structure formula is given as Ba2(La0.727Ba0.182M0.091)MO6. This model was confirmed by Rietveld refinement of the XRD data. The emission spectra of Eu3+ showed a strong dependence on its local site symmetry in the host material, in which it is being doped and this can be used as a spectroscopic probe for detecting any differences in the symmetry. Comparison of the local symmetry around La3+ cation was studied using photoluminescence (PL) by doping 2 atom% Eu3+ in LaM and La2/3M compounds. Infrared spectroscopy (IRS) analyses were also carried out for LaM and La2/3M compounds. There was complete agreement between the PL and IRS results and they were also in concordance with the predicted crystal structure model. Interestingly in these La2/3M compounds, the equilibrium structure prefers large Ba2+ ion to occupy the octahedral B-site rather than forming an octahedral vacancy at that site, making these perovskite compounds rare and novel in their class.
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Affiliation(s)
- Rohan Phatak
- Fuel Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, India. and Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai-400094, India
| | - Santosh K Gupta
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, India
| | - Priya Maheshwari
- Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, India
| | - Amitabh Das
- Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, India.
| | - Sanjay K Sali
- Fuel Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400085, India.
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Soldatov A, Lamoen D, Konstantinović M, Van den Berghe S, Scheinost A, Verwerft M. Local structure and oxidation state of uranium in some ternary oxides: X-ray absorption analysis. J SOLID STATE CHEM 2007. [DOI: 10.1016/j.jssc.2006.08.038] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Conradson SD, Begg BD, Clark DL, den Auwer C, Ding M, Dorhout PK, Espinosa-Faller FJ, Gordon PL, Haire RG, Hess NJ, Hess RF, Webster Keogh D, Lander GH, Manara D, Morales LA, Neu MP, Paviet-Hartmann P, Rebizant J, Rondinella VV, Runde W, Drew Tait C, Kirk Veirs D, Villella PM, Wastin F. Charge distribution and local structure and speciation in the UO2+x and PuO2+x binary oxides for x⩽0.25. J SOLID STATE CHEM 2005. [DOI: 10.1016/j.jssc.2004.09.029] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Conradson SD, Manara D, Wastin F, Clark DL, Lander GH, Morales LA, Rebizant J, Rondinella VV. Local Structure and Charge Distribution in the UO2−U4O9 System. Inorg Chem 2004; 43:6922-35. [PMID: 15500330 DOI: 10.1021/ic049748z] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Analysis of X-ray absorption fine structure spectra of UO(2+x) for x = 0-0.20 (UO(2)--U(4)O(9)) reveals that the adventitious O atoms are incorporated as oxo groups with U--O distances of 1.74 A, most likely associated with U(VI), that occur in clusters so that the UO(2) fraction of the material largely remains intact. In addition to the formation of some additional longer U--O bonds, the U sublattice consists of an ordered portion that displays the original U--U distance and a spectroscopically silent, glassy part. This is very different from previous models derived from neutron diffraction that maintained long U--O distances and high U--O coordination numbers. UO(2+x) also differs from PuO(2+x) in its substantially shorter An-oxo distances and no sign of stable coordination with H(2)O and its hydrolysis products.
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Affiliation(s)
- Steven D Conradson
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA.
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Properties of Mixing. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1874-5644(03)80011-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Cordfunke E, Huntelaar M, IJdo D. The Structure of BaSr4U3O14 and a Structural and Thermodynamic Characterization of Sr5U3O14. J SOLID STATE CHEM 1999. [DOI: 10.1006/jssc.1999.8320] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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