1
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DiBlasi NA, Tasi AG, Trumm M, Schnurr A, Gaona X, Fellhauer D, Dardenne K, Rothe J, Reed DT, Hixon AE, Altmaier M. Pu(iii) and Cm(iii) in the presence of EDTA: aqueous speciation, redox behavior, and the impact of Ca(ii). RSC Adv 2022; 12:9478-9493. [PMID: 35424870 PMCID: PMC8985188 DOI: 10.1039/d1ra09010k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 03/14/2022] [Indexed: 11/21/2022] Open
Abstract
The impact of calcium on the solubility, redox behavior, and speciation of the An(iii)–EDTA (An = Pu or Cm) system under reducing, anoxic conditions was investigated through batch solubility experiments, X-ray absorption spectroscopy (XAS), density functional theory (DFT), and time-resolved laser fluorescence spectroscopy (TRLFS). Batch solubility experiments were conducted from undersaturation using Pu(OH)3(am) as the solid phase in contact with 0.1 M NaCl–NaOH–HCl–EDTA–CaCl2 solutions at [EDTA] = 1 mM, pHm = 7.5–9.5, and [CaCl2] ≤20 mM. Additional samples targeted brine systems represented by 3.5 M CaCl2 and WIPP simulated brine. Solubility data in the absence of calcium were well-described by Pu(iii)–EDTA thermodynamic models, thus supporting the stabilization of Pu(iii)–EDTA complexes in solution. Cm(iii)–EDTA TRLFS data suggested the stepwise hydrolysis of An(iii)-EDTA complexes with increasing pH, and current Pu(iii)-EDTA solubility models were reassessed to evaluate the possibility of including Pu(iii)–OH–EDTA complexes and to calculate preliminary formation constants. Solubility data in the presence of calcium exhibited nearly constant log m(Pu)tot, as limited by total ligand concentration, with increasing [CaCl2]tot, which supports the formation of calcium-stabilized Pu(iii)–EDTA complexes in solution. XAS spectra without calcium showed partial oxidation of Pu(iii) to Pu(iv) in the aqueous phase, while calcium-containing experiments exhibited only Pu(iii), suggesting that Ca–Pu(iii)–EDTA complexes may stabilize Pu(iii) over short timeframes (t ≤45 days). DFT calculations on the Ca–Pu(iii)–EDTA system and TRLFS studies on the analogous Ca–Cm(iii)–EDTA system show that calcium likely stabilizes An(iii)–EDTA complexes but can also potentially stabilize An(iii)–OH–EDTA species in solution. This hints towards the possible existence of four major complex types within Ca–An(iii)–EDTA systems: An(iii)–EDTA, An(iii)–OH–EDTA, Ca–An(iii)–EDTA, and Ca–An(iii)–OH–EDTA. While the exact stoichiometry and degree of ligand protonation within these complexes remain undefined, their formation must be accounted for to properly assess the fate and transport of plutonium under conditions relevant to nuclear waste disposal. Combined advanced spectroscopy and solubility studies provide evidence for the formation of novel calcium-containing and hydrolyzed (Cm,Pu)(iii)–EDTA complex(es).![]()
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Affiliation(s)
- Nicole A DiBlasi
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame 301 Stinson-Remick, Notre Dame IN 46556 USA .,Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal P.O. Box 3640 Karlsruhe 76021 Germany
| | - Agost G Tasi
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal P.O. Box 3640 Karlsruhe 76021 Germany
| | - Michael Trumm
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal P.O. Box 3640 Karlsruhe 76021 Germany
| | - Andreas Schnurr
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal P.O. Box 3640 Karlsruhe 76021 Germany
| | - Xavier Gaona
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal P.O. Box 3640 Karlsruhe 76021 Germany
| | - David Fellhauer
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal P.O. Box 3640 Karlsruhe 76021 Germany
| | - Kathy Dardenne
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal P.O. Box 3640 Karlsruhe 76021 Germany
| | - Jörg Rothe
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal P.O. Box 3640 Karlsruhe 76021 Germany
| | - Donald T Reed
- Los Alamos National Laboratory 1400 University Dr. Carlsbad NM 88220 USA
| | - Amy E Hixon
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame 301 Stinson-Remick, Notre Dame IN 46556 USA
| | - Marcus Altmaier
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal P.O. Box 3640 Karlsruhe 76021 Germany
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2
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DiBlasi NA, Tasi AG, Gaona X, Fellhauer D, Dardenne K, Rothe J, Reed DT, Hixon AE, Altmaier M. Impact of Ca(II) on the aqueous speciation, redox behavior, and environmental mobility of Pu(IV) in the presence of EDTA. Sci Total Environ 2021; 783:146993. [PMID: 33866175 DOI: 10.1016/j.scitotenv.2021.146993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/01/2021] [Accepted: 04/03/2021] [Indexed: 06/12/2023]
Abstract
The impact of calcium on the solubility and redox behavior of the Pu(IV)-EDTA system was investigated using a combination of undersaturation solubility studies and advanced spectroscopic techniques. Batch solubility experiments were conducted in 0.1 M NaCl-NaOH-HCl-EDTA-CaCl2 solutions at constant [EDTA] = 1∙10-3 M, 1 ≤ pHm ≤ 11, and 1∙10-3 M ≤ [CaCl2] ≤ 2∙10-2 M. Additional samples targeted brine systems represented by 3.5 M CaCl2 and WIPP simulated brine. Redox conditions were buffered with hydroquinone (pe + pH ≈ 9.5) with selected samples prepared in the absence of any redox buffer. All experiments were performed at T = 22 °C under Ar atmosphere. In-situ X-ray absorption spectroscopy indicated that PuO2(ncr,hyd) was the solubility-controlling phase during the lifetime of all experiments and that aqueous plutonium was present in the +IV oxidation state across all experimental conditions except at pHm ≈ 1, where a small fraction of Pu(III) was also identified. Current thermodynamic models overestimate Pu(IV)-EDTA solubility in the absence of calcium by approximately 1-1.5 log10-units and do not describe the nearly pH-independent, increased solubility observed with increased calcium concentrations. The ternary Pu(IV)-OH-EDTA system without calcium was reevaluated using solubility data obtained in this work and reported in the literature. An updated thermodynamic model including the complexes Pu(OH)(EDTA)-, Pu(OH)2(EDTA)2-, and Pu(OH)3(EDTA)3- was derived. Solubility data collected in the presence of calcium follows a pH-independent trend (log m(Pu)tot vs. pHm), which can only be explained by assuming the formation of a quaternary complex, tentatively defined as CaPu(OH)4(EDTA)2-, in solution. The significant enhancement of plutonium solubility observed in the investigated brine systems supports the formation of a quaternary complex that is not outcompeted by Ca(EDTA)2-, even in concentrated CaCl2 solutions. Although the exact stoichiometry of the complex may need to be revisited, this new quaternary complex has a pronounced impact on plutonium predominance diagrams over a broad range of pH, pe, and calcium concentrations that are relevant to nuclear waste disposal.
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Affiliation(s)
- Nicole A DiBlasi
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, 301 Stinson-Remick, Notre Dame, IN 46556, United States of America
| | - Agost G Tasi
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Xavier Gaona
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, 76021 Karlsruhe, Germany.
| | - David Fellhauer
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Kathy Dardenne
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Jörg Rothe
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Donald T Reed
- Los Alamos National Laboratory, 1400 University Dr., Carlsbad, NM 88220, United States of America
| | - Amy E Hixon
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, 301 Stinson-Remick, Notre Dame, IN 46556, United States of America.
| | - Marcus Altmaier
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal, P.O. Box 3640, 76021 Karlsruhe, Germany
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3
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DiBlasi NA, Yalçintas E, Stanley FE, Reed DT, Hixon AE. Influence of ethylenediaminetetraacetic acid on the long-term oxidation state distribution of plutonium. Chemosphere 2021; 274:129741. [PMID: 33545584 DOI: 10.1016/j.chemosphere.2021.129741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 01/08/2021] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
Spectrophotometry was used to study the effect of EDTA on plutonium oxidation state distribution as a function of time, pH, and ligand-to-metal ratio (L/M) under anoxic conditions. Novel Pu(V)-EDTA absorption bands were identified at 571, 993, 1105, and 1150 nm with molar absorption coefficients of 15 ± 1, 6 ± 1, 10 ± 1, and 10 ± 1 cm-1M-1, respectively. Pu(V)-EDTA spectral changes occurred at L/M < 1, indicating only PuVO2(EDTA)3- formed with logK = 3.6 ± 0.3. Time-resolved experiments showed EDTA drastically increased the Pu(V/VI) reduction rate, which we propose is driven by amine lone-pair electron donation and the oxidative decarboxylation of EDTA. Oxidation of Pu(III)-EDTA to Pu(IV)-EDTA occurred on a slower time scale (110-237 days) than previously reported (<15 min) and is hypothesized to be radiolysis driven. Pu(V/VI)-EDTA and Pu(III)-EDTA both approached Pu(IV)-EDTA stabilization over time, yet Pu(V/VI)-EDTA solubility data was ≥ 1.0 log10 units higher than predicted by Pu(IV)-EDTA solubility models, indicating that current thermodynamic models are incomplete. Ultimately, the data show EDTA preferentially stabilizes Pu(IV) over time regardless of initial oxidation state, but Pu(V)-EDTA can persist under environmentally-relevant conditions, emphasizing the need to continue investigating redox reactions, speciation, and behavior of these complexes to support the transuranic waste disposal and surface remediation/containment efforts.
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Affiliation(s)
- Nicole A DiBlasi
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, 301 Stinson-Remick Hall, Notre Dame, IN, 46556, USA; Los Alamos National Laboratory, 1400 University Dr., Carlsbad, NM, 88220, USA
| | - Ezgi Yalçintas
- Los Alamos National Laboratory, 1400 University Dr., Carlsbad, NM, 88220, USA
| | - Floyd E Stanley
- Los Alamos National Laboratory, 1400 University Dr., Carlsbad, NM, 88220, USA
| | - Donald T Reed
- Los Alamos National Laboratory, 1400 University Dr., Carlsbad, NM, 88220, USA
| | - Amy E Hixon
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame, 301 Stinson-Remick Hall, Notre Dame, IN, 46556, USA.
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4
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Emerson HP, Zengotita F, Richmann M, Katsenovich Y, Reed DT, Dittrich TM. Retention of neodymium by dolomite at variable ionic strength as probed by batch and column experiments. J Environ Radioact 2018; 190-191:89-96. [PMID: 29775842 DOI: 10.1016/j.jenvrad.2018.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/21/2018] [Accepted: 05/06/2018] [Indexed: 06/08/2023]
Abstract
The results presented in this paper highlight the complexity of adsorption and incorporation processes of Nd with dolomite and significantly improve upon previous work investigating trivalent actinide and lanthanide interactions with dolomite. Both batch and mini column experiments were conducted at variable ionic strength. These data highlight the strong chemisorption of Nd to the dolomite surface (equilibrium Kd's > 3000 mL/g) and suggest that equilibrium adsorption processes may not be affected by ionic strength based on similar results at 0.1 and 5.0 M ionic strength in column breakthrough and equilibrium batch (>5 days) results. Mini column experiments conducted over approximately one year also represent a significant development in measurement of sorption of Nd in the presence of flow as previous large-scale column experiments did not achieve breakthrough likely due to the high loading capacity of dolomite for Nd (up to 240 μg/g). Batch experiments in the absence of flow show that the rate of Nd removal increases with increasing ionic strength (up to 5.0 M) with greater removal at greater ionic strength for a 24 h sampling point. We suggest that the increasing ionic strength induces increased mineral dissolution and re-precipitation caused by changes in activity with ionic strength that lead to increased removal of Nd through co-precipitation processes.
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Affiliation(s)
- H P Emerson
- Applied Research Center, Florida International University, 10555 W Flagler St, Miami, FL, 33174, United States.
| | - F Zengotita
- Applied Research Center, Florida International University, 10555 W Flagler St, Miami, FL, 33174, United States
| | - M Richmann
- Repository Science and Operations, Los Alamos National Laboratory, 1400 University Drive, Carlsbad, NM, 88220, United States
| | - Y Katsenovich
- Applied Research Center, Florida International University, 10555 W Flagler St, Miami, FL, 33174, United States
| | - D T Reed
- Repository Science and Operations, Los Alamos National Laboratory, 1400 University Drive, Carlsbad, NM, 88220, United States
| | - T M Dittrich
- Repository Science and Operations, Los Alamos National Laboratory, 1400 University Drive, Carlsbad, NM, 88220, United States; Department of Civil and Environmental Engineering, Wayne State University, 5050 Anthony Wayne Drive, Detroit, MI, 48202, United States
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5
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Bader M, Müller K, Foerstendorf H, Schmidt M, Simmons K, Swanson JS, Reed DT, Stumpf T, Cherkouk A. Comparative analysis of uranium bioassociation with halophilic bacteria and archaea. PLoS One 2018; 13:e0190953. [PMID: 29329319 PMCID: PMC5766140 DOI: 10.1371/journal.pone.0190953] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 12/23/2017] [Indexed: 11/18/2022] Open
Abstract
Rock salt represents a potential host rock formation for the final disposal of radioactive waste. The interactions between indigenous microorganisms and radionuclides, e.g. uranium, need to be investigated to better predict the influence of microorganisms on the safety assessment of the repository. Hence, the association process of uranium with two microorganisms isolated from rock salt was comparatively studied. Brachybacterium sp. G1, which was isolated from the German salt dome Gorleben, and Halobacterium noricense DSM15987T, were selected as examples of a moderately halophilic bacterium and an extremely halophilic archaeon, respectively. The microorganisms exhibited completely different association behaviors with uranium. While a pure biosorption process took place with Brachybacterium sp. G1 cells, a multistage association process occurred with the archaeon. In addition to batch experiments, in situ attenuated total reflection Fourier-transform infrared spectroscopy was applied to characterize the U(VI) interaction process. Biosorption was identified as the dominating process for Brachybacterium sp. G1 with this method. Carboxylic functionalities are the dominant interacting groups for the bacterium, whereas phosphoryl groups are also involved in U(VI) association by the archaeon H. noricense.
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Affiliation(s)
- Miriam Bader
- Helmholtz-Zentrum Dresden—Rossendorf, Institute of Resource Ecology, Dresden, Germany
| | - Katharina Müller
- Helmholtz-Zentrum Dresden—Rossendorf, Institute of Resource Ecology, Dresden, Germany
| | - Harald Foerstendorf
- Helmholtz-Zentrum Dresden—Rossendorf, Institute of Resource Ecology, Dresden, Germany
| | - Matthias Schmidt
- Helmholtz Centre for Environmental Research - UFZ, Department of Isotope Biogeochemistry, Leipzig, Germany
| | - Karen Simmons
- Los Alamos National Laboratory Carlsbad Operations, Repository Science and Operations, Carlsbad, New Mexico, United States of America
| | - Juliet S. Swanson
- Los Alamos National Laboratory Carlsbad Operations, Repository Science and Operations, Carlsbad, New Mexico, United States of America
| | - Donald T. Reed
- Los Alamos National Laboratory Carlsbad Operations, Repository Science and Operations, Carlsbad, New Mexico, United States of America
| | - Thorsten Stumpf
- Helmholtz-Zentrum Dresden—Rossendorf, Institute of Resource Ecology, Dresden, Germany
| | - Andrea Cherkouk
- Helmholtz-Zentrum Dresden—Rossendorf, Institute of Resource Ecology, Dresden, Germany
- * E-mail:
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6
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Bader M, Müller K, Foerstendorf H, Drobot B, Schmidt M, Musat N, Swanson JS, Reed DT, Stumpf T, Cherkouk A. Multistage bioassociation of uranium onto an extremely halophilic archaeon revealed by a unique combination of spectroscopic and microscopic techniques. J Hazard Mater 2017; 327:225-232. [PMID: 28081458 DOI: 10.1016/j.jhazmat.2016.12.053] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 12/09/2016] [Accepted: 12/26/2016] [Indexed: 06/06/2023]
Abstract
The interactions of two extremely halophilic archaea with uranium were investigated at high ionic strength as a function of time, pH and uranium concentration. Halobacterium noricense DSM-15987 and Halobacterium sp. putatively noricense, isolated from the Waste Isolation Pilot Plant repository, were used for these investigations. The kinetics of U(VI) bioassociation with both strains showed an atypical multistage behavior, meaning that after an initial phase of U(VI) sorption, an unexpected interim period of U(VI) release was observed, followed by a slow reassociation of uranium with the cells. By applying in situ attenuated total reflection Fourier-transform infrared spectroscopy, the involvement of phosphoryl and carboxylate groups in U(VI) complexation during the first biosorption phase was shown. Differences in cell morphology and uranium localization become visible at different stages of the bioassociation process, as shown with scanning electron microscopy in combination with energy dispersive X-ray spectroscopy. Our results demonstrate for the first time that association of uranium with the extremely halophilic archaeon is a multistage process, beginning with sorption and followed by another process, probably biomineralization.
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Affiliation(s)
- Miriam Bader
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Katharina Müller
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Harald Foerstendorf
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Björn Drobot
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Matthias Schmidt
- Helmholtz Centre for Environmental Research-UFZ, Department of Isotope Biogeochemistry, Permoserstraße 15, 04318 Leipzig, Germany
| | - Niculina Musat
- Helmholtz Centre for Environmental Research-UFZ, Department of Isotope Biogeochemistry, Permoserstraße 15, 04318 Leipzig, Germany
| | - Juliet S Swanson
- Los Alamos National Laboratory, Repository Science and Operations, 1400 University Drive, Carlsbad, NM, 88220, USA
| | - Donald T Reed
- Los Alamos National Laboratory, Repository Science and Operations, 1400 University Drive, Carlsbad, NM, 88220, USA
| | - Thorsten Stumpf
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Andrea Cherkouk
- Helmholtz-Zentrum Dresden - Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany.
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7
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Batuk ON, Conradson SD, Aleksandrova ON, Boukhalfa H, Burakov BE, Clark DL, Czerwinski KR, Felmy AR, Lezama-Pacheco JS, Kalmykov SN, Moore DA, Myasoedov BF, Reed DT, Reilly DD, Roback RC, Vlasova IE, Webb SM, Wilkerson MP. Multiscale Speciation of U and Pu at Chernobyl, Hanford, Los Alamos, McGuire AFB, Mayak, and Rocky Flats. Environ Sci Technol 2015; 49:6474-6484. [PMID: 25815708 DOI: 10.1021/es506145b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The speciation of U and Pu in soil and concrete from Rocky Flats and in particles from soils from Chernobyl, Hanford, Los Alamos, and McGuire Air Force Base and bottom sediments from Mayak was determined by a combination of X-ray absorption fine structure (XAFS) spectroscopy and X-ray fluorescence (XRF) element maps. These experiments identify four types of speciation that sometimes may and other times do not exhibit an association with the source terms and histories of these samples: relatively well ordered PuO2+x and UO2+x that had equilibrated with O2 and H2O under both ambient conditions and in fires or explosions; instances of small, isolated particles of U as UO2+x, U3O8, and U(VI) species coexisting in close proximity after decades in the environment; alteration phases of uranyl with other elements including ones that would not have come from soils; and mononuclear Pu-O species and novel PuO2+x-type compounds incorporating additional elements that may have occurred because the Pu was exposed to extreme chemical conditions such as acidic solutions released directly into soil or concrete. Our results therefore directly demonstrate instances of novel complexity in the Å and μm-scale chemical speciation and reactivity of U and Pu in their initial formation and after environmental exposure as well as occasions of unexpected behavior in the reaction pathways over short geological but significant sociological times. They also show that incorporating the actual disposal and site conditions and resultant novel materials such as those reported here may be necessary to develop the most accurate predictive models for Pu and U in the environment.
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Affiliation(s)
- Olga N Batuk
- ‡Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Steven D Conradson
- †Synchrotron-SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP48, 91192, France
- ‡Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | | | - Hakim Boukhalfa
- ‡Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Boris E Burakov
- ∥V.G. Khlopin Radium Institute, 28, 2-nd Murinskiy Ave., St. Petersburg 194021, Russia
| | - David L Clark
- ‡Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Ken R Czerwinski
- ⊥University of Nevada, MSM 245, 4505 S. Maryland Pkwy, Las Vegas, Nevada 89154, United States
| | - Andrew R Felmy
- #Pacific Northwest National Laboratory, PO Box 999 MSIN: K8-96, Richland, Washington 99352, United States
| | - Juan S Lezama-Pacheco
- ∇Environmental Earth System Sciences Department, 473 Via Ortega, Stanford University, Stanford California 94305-4216, United States
| | - Stepan N Kalmykov
- ○Radiochemistry Division, Chemistry Department, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia
- ◆Frumkin Institute of Physical Chemistry and Electrochemistry of RAS, Leninsky av. 31, Moscow 119071, Russia
| | - Dean A Moore
- #Pacific Northwest National Laboratory, PO Box 999 MSIN: K8-96, Richland, Washington 99352, United States
| | - Boris F Myasoedov
- ◆Frumkin Institute of Physical Chemistry and Electrochemistry of RAS, Leninsky av. 31, Moscow 119071, Russia
| | - Donald T Reed
- ‡Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Dallas D Reilly
- #Pacific Northwest National Laboratory, PO Box 999 MSIN: K8-96, Richland, Washington 99352, United States
| | - Robert C Roback
- ‡Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Irina E Vlasova
- ○Radiochemistry Division, Chemistry Department, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia
| | - Samuel M Webb
- ¶SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
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8
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Hinz K, Altmaier M, Gaona X, Rabung T, Schild D, Richmann M, Reed DT, Alekseev EV, Geckeis H. Interaction of Nd(iii) and Cm(iii) with borate in dilute to concentrated alkaline NaCl, MgCl2 and CaCl2 solutions: solubility and TRLFS studies. NEW J CHEM 2015. [DOI: 10.1039/c4nj01203h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Interaction of Ln(iii) and An(iii) with borate impacts radionuclide solubility and speciation in saline aqueous solutions.
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Affiliation(s)
- Katja Hinz
- Institute for Nuclear Waste Disposal
- Karlsruhe Institute of Technology
- 76021 Karlsruhe
- Germany
| | - Marcus Altmaier
- Institute for Nuclear Waste Disposal
- Karlsruhe Institute of Technology
- 76021 Karlsruhe
- Germany
| | - Xavier Gaona
- Institute for Nuclear Waste Disposal
- Karlsruhe Institute of Technology
- 76021 Karlsruhe
- Germany
| | - Thomas Rabung
- Institute for Nuclear Waste Disposal
- Karlsruhe Institute of Technology
- 76021 Karlsruhe
- Germany
| | - Dieter Schild
- Institute for Nuclear Waste Disposal
- Karlsruhe Institute of Technology
- 76021 Karlsruhe
- Germany
| | - Michael Richmann
- Los Alamos National Laboratory
- Repository Science and Operations
- Carlsbad
- USA
| | - Donald T. Reed
- Los Alamos National Laboratory
- Repository Science and Operations
- Carlsbad
- USA
| | - Evgeny V. Alekseev
- Institute of Energy and Climate Research (IEK-6)
- Forschungszentrum Jülich
- 52428 Jülich
- Germany
- Institut für Kristallographie
| | - Horst Geckeis
- Institute for Nuclear Waste Disposal
- Karlsruhe Institute of Technology
- 76021 Karlsruhe
- Germany
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9
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Abstract
Abstract
The solubility of uranium(VI) was determined in WIPP-relevant brines as a function of pCH+
and ionic strength, in the absence of carbonate. Carbonate concentration was below 2 × 105 M, measured using the gas chromatography method. In the absence of carbonate, the uranium(VI) solubilities were about × 106 M in GWB at pCH+
≥7 and about × 108– × 107 M in ERDA-6 brine at pCH+
≥8. Solubility of uranium(VI) was also measured in NaCl media at the same levels as in ERDA-6 brine. The data established a uranium solubility that was 10–100 times lower than published results from Diaz-Arocas and Grambow [13], and they are in good agreement with modeling results and other literature data [11,12]. In the absence of carbonate, hydrolysis was the main complexation and precipitation mechanisms for uranium(VI) solubility at high ionic strength and pC
H+
≥7. However, the effect of borate complexation was noticeable at pCH+
∼8–9.
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10
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Abstract
Abstract
Four pillared metal(IV) phosphate-phosphonate ion exchange materials were synthesized and characterized. Studies were conducted to determine their affinity for the lanthanides (Ln´s) and actinides (An´s). It was determined that by simply manipulating the metal source (Zr or Sn) and the phosphate source (H3PO4 or Na3PO4) large differences were seen in the extraction of the Ln and An species. K
d values higher than 4×105 were observed for the AnO2
2+ species in nitric acid at pH 2. These basic uptake experiments are important, as the data they provide may indicate the possibility of a separation of Ln´s from An´s or even more notably americium from curium and Ln´s.
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Affiliation(s)
- J. D. Burns
- Texas A&M University, Department of Chemistry, TX 77843-3255, U.S.A
| | | | - Marian Borkowski
- Los Alamos National Laboratory, Earth and Environmental Sciences Division, Carlsbad, NM 88220, U.S.A
| | - Donald T. Reed
- Los Alamos National Laboratory, Earth and Environmental Sciences Division, Carlsbad, U.S.A
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Borkowski M, Richmann M, Reed DT, Xiong Y. Complexation of Nd(III) with tetraborate ion and its effect on actinide(III) solubility in WIPP brine. ACTA ACUST UNITED AC 2010. [DOI: 10.1524/ract.2010.1756] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
The potential importance of tetraborate complexation on lanthanide(III) and actinide(III) solubility is recognized in the literature but a systematic study of f-element complexation has not been performed. In neodymium solubility studies in WIPP brines, the carbonate complexation effect is not observed since tetraborate ions form a moderately strong complex with neodymium(III). The existence of these tetraborate complexes was established for low and high ionic strength solutions. Changes in neodymium(III) concentrations in undersaturation experiments were used to determine the neodymium with tetraborate stability constants as a function of NaCl ionic strength. As very low Nd(III) concentrations have to be measured, it was necessary to use an extraction pre-concentration step combined with ICP-MS analysis to extend the detection limit by a factor of 50.
The determined Nd(III) with borate stability constants at infinite dilution and 25 °C are equal to logβ1=4.55±0.06 using the SIT approach, equal to logβ1=4.99±0.30 using the Pitzer approach, with an apparent logβ1=4.06±0.15 (in molal units) at I=5.6 m NaCl. Pitzer ion-interaction parameters for neodymium with tetraborate and SIT interaction coefficients were also determined and reported.
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Affiliation(s)
| | - Michael Richmann
- Los Alamos National Laboratory, Earth and Environmental Sciences Division, Carlsbad, NM 88220, U.S.A
| | - Donald T. Reed
- Los Alamos National Laboratory, Earth and Environmental Sciences Division, Carlsbad, U.S.A
| | - Yongliang Xiong
- Sandia National Laboratories, Carlsbad Program Group, Carlsbad, NM 88220, U.S.A
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Deo RP, Songkasiri W, Rittmann BE, Reed DT. Surface complexation of Neptunium(V) onto whole cells and cell components of Shewanella alga: modeling and experimental study. Environ Sci Technol 2010; 44:4930-4935. [PMID: 20521812 DOI: 10.1021/es9035336] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We systematically quantified surface complexation of Np(V) onto whole cells, cell wall, and extracellular polymeric substances (EPS) of Shewanella alga strain BrY. We first performed acid and base titrations and used the mathematical model FITEQL to estimate the concentrations and deprotonation constants of specific surface functional groups. Deprotonation constants most likely corresponded to a carboxyl group not associated with amino acids (pK(a) approximately 5), a phosphoryl site (pK(a) approximately 7.2), and an amine site (pK(a) > 10). We then carried out batch sorption experiments with Np(V) and each of the S. alga components as a function of pH. Since significant Np(V) sorption was observed on S. alga whole cells and its components in the pH range 2-5, we assumed the existence of a fourth site: a low-pK(a) carboxyl site (pK(a) approximately 2.4) that is associated with amino acids. We used the SPECIATE submodel of the biogeochemical model CCBATCH to compute the stability constants for Np(V) complexation to each surface functional group. The stability constants were similar for each functional group on S. alga bacterial whole cells, cell walls, and EPS, and they explain the complicated sorption patterns when they are combined with the aqueous-phase speciation of Np(V). For pH < 8, the aquo NpO(2)(+) species was the dominant form of Np(V), and its log K values for the low-pK(a) carboxyl, mid-pK(a) carboxyl, and phosphoryl groups were 1.8, 1.8, and 2.5-3.1, respectively. For pH greater than 8, the key surface ligand was amine >XNH(3)(+), which complexed with NpO(2)(CO(3))(3)(5-). The log K for NpO(2)(CO(3))(3)(5-) complexed onto the amine groups was 3.1-3.9. All of the log K values are similar to those of Np(V) complexes with aqueous carboxyl and N-containing carboxyl ligands. These results help quantify the role of surface complexation in defining actinide-microbiological interactions in the subsurface.
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Affiliation(s)
- Randhir P Deo
- Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, Tempe, Arizona 85287-5701, USA
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Abstract
The redox stability of PuO2
2+ was investigated in brine under subsurface conditions. In simulated brines, when no reducing agent was present, 0.1 mM concentrations of plutonium(VI) were stable as regards to reduction for over two years, which was the duration of the experiments performed. In these systems, the plutonyl existed as a carbonate or hydroxy-chloride species. The introduction of reducing agents (e.g. steel coupons, and aqueous Fe2+) typically present in a subsurface repository, however, led to the destabilization of the plutonium(VI) complexes and the subsequent reduction to Pu(IV) under most conditions investigated. X-ray Absorption Near-Edge Spectroscopy (XANES) confirmed that the final oxidation state in these systems was Pu(IV). This reduction lowered the overall steady state concentration of plutonium in the brine by 3−4 orders of magnitude. These results show the importance of considering repository constituents in evaluating subsurface actinide solubility/mobility and provide further evidence of the effectiveness of reduced iron species in the reduction and immobilization of higher-valent plutonium species.
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Abstract
A combination of experimental, analytical, and modeling investigations shows that an anaerobic, sulfate-reducing consortium reduced Np(V) to Np(IV), with subsequent precipitation of a Np(IV) solid. Precipitation of Np(IV) during growth on pyruvate occurred before sulfate reduction began. H2 stimulated precipitation of Np(IV) when added alone to growing cells, but it slowed precipitation when added along with pyruvate. Increasing concentrations of pyruvate also retarded precipitation. Accumulation of an intermediate pyruvate-fermentation product--probably succinate--played a key role in retarding Np(IV) precipitation by complexing the Np(IV). Hydrogen appears to have two roles in controlling Np precipitation: donating electrons for Np(V) reduction and modulating intermediate levels. That Np(V) is microbially reduced and subsequently precipitated under anaerobic conditions has likely beneficial implications for the containment of Np on lands contaminated by radionuclides, but complexation by fermentation intermediates can prevent immobilization by precipitation.
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Affiliation(s)
- Bruce E Rittmann
- Department of Civil and Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3109, USA
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Abstract
We expand the biogeochemical model CCBATCH to include a precipitation/dissolution sub-model that contains kinetic and equilibrium options. This advancement extends CCBATCH's usefulness to situations in which microbial reactions cause or are affected by formation or dissolution of a solid phase. The kinetic option employs a rate expression that explicitly includes the intrinsic kinetics for reaction or mass-transport control, the difference from thermodynamic equilibrium, and the aqueous concentration of the rate-limiting metal or ligand. The equilibrium feature can be used alone, and it also serves as check that the kinetic rate never is too fast and "overshoots" equilibrium. The features of the expanded CCBATCH are illustrated by an example in which the precipitation of Fe(OH)3(s) allows the biodegradation of citric acid, even though complexes are strong and not bioavailable. Precipitation releases citrate ligand, and biodegradation of the citrate increases the pH.
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Affiliation(s)
- Bruce E Rittmann
- Department of Civil and Environmental Engineering, Northwestern University, 2145 N. Sheridan Road, Evanston, IL 60208-3109, USA
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Reed DT, Dorfman LM. Rate constants and activation energies for reaction of benzyl cation with ethers in solution: initial step in carbocationic polymerization. Macromolecules 2002. [DOI: 10.1021/ma00131a006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Affiliation(s)
- Spiridoula Matsika
- Department of Chemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210
| | - Russell M. Pitzer
- Department of Chemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210
| | - Donald T. Reed
- Chemical Technology Division, Argonne National Laboratory, Argonne, Illinois 60439
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Abstract
The radiotoxicity of plutonium in NTA-degrading Chelatobacter heintzii cell suspensions was investigated as part of a more general study to establish the key interactions between actinide-organic complexes and microorganisms in the subsurface. The radiation tolerance of C. heintzii, based on 60Co gamma irradiation experiments, was 165 +/- 30 Gy. No bacteria survived irradiation doses greater than 500 Gy. In the presence of plutonium, where alpha particle decay was the primary source of ionizing radiation, the observed toxicity was predominantly radiolytic rather than chemical. This was evident by the greater effect of activity, rather than concentration, on the toxicity noted. Bioassociation of plutonium with C. heintzii was postulated to be an important and necessary step in the observed loss of cell viability since this was the best way to account for the observed death rate. The radiotoxicity of plutonium towards bacteria is a potentially important consideration in the bioremediation of sites contaminated with radionuclide-organic mixtures and the bioprocessing of nuclear waste.
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Affiliation(s)
- D T Reed
- Chemical Technology Division, Argonne National Laboratory, IL 60439, USA.
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Meckstroth WK, Reed DT, Wojcicki A. Further pulse radiolysis studies of decacarbonyldimanganese(O) and decacarbonyldirhenium(O). Temperature and solvent effects. Inorganica Chim Acta 1985. [DOI: 10.1016/s0020-1693(00)90554-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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