1
|
Niklas JE, Otte KS, Studvick CM, Roy Chowdhury S, Vlaisavljevich B, Bacsa J, Kleemiss F, Popov IA, La Pierre HS. A tetrahedral neptunium(V) complex. Nat Chem 2024:10.1038/s41557-024-01529-6. [PMID: 38710831 DOI: 10.1038/s41557-024-01529-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Accepted: 04/05/2024] [Indexed: 05/08/2024]
Abstract
Neptunium is an actinide element sourced from anthropogenic production, and, unlike naturally abundant uranium, its coordination chemistry is not well developed in all accessible oxidation states. High-valent neptunium generally requires stabilization from at least one metal-ligand multiple bond, and departing from this structural motif poses a considerable challenge. Here we report a tetrahedral molecular neptunium(V) complex ([Np5+(NPC)4][B(ArF5)4], 1-Np) (NPC = [NPtBu(pyrr)2]-; tBu = C(CH3)3; pyrr = pyrrolidinyl (N(C2H4)2); B(ArF5)4 = tetrakis(2,3,4,5,6-pentafluourophenyl)borate). Single-crystal X-ray diffraction, solution-state spectroscopy and density functional theory studies of 1-Np and the product of its proton-coupled electron transfer (PCET) reaction, 2-Np, demonstrate the unique bonding that stabilizes this reactive ion and establishes the thermochemical and kinetic parameters of PCET in a condensed-phase transuranic complex. The isolation of this four-coordinate, neptunium(V) complex reveals a fundamental reaction pathway in transuranic chemistry.
Collapse
Affiliation(s)
- Julie E Niklas
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - Kaitlyn S Otte
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - Chad M Studvick
- Department of Chemistry, The University of Akron, Akron, OH, USA
| | | | | | - John Bacsa
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | - Florian Kleemiss
- Institut für Anorganische Chemie, RWTH Aachen University, Aachen, Germany
| | - Ivan A Popov
- Department of Chemistry, The University of Akron, Akron, OH, USA.
| | - Henry S La Pierre
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.
- Nuclear and Radiological Engineering and Medical Physics Program, School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA.
| |
Collapse
|
2
|
Srivastava A, Ali SM, Dumpala RMR, Kumar S, Kumar P, Rawat N, Mohapatra PK. Unusual redox stability of pentavalent uranium with hetero-bifunctional phosphonocarboxylate: insight into aqueous speciation. Dalton Trans 2024; 53:7321-7339. [PMID: 38591248 DOI: 10.1039/d4dt00173g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024]
Abstract
The +5 state is an unusual oxidation state of uranium due to its instability in the aqueous phase. As a result, gaining information about its aqueous speciation is extremely difficult. The present work is an attempt in that direction and it provides insight into the existence of a new pentavalent species in the presence of hetero-bifunctional phosphonocarboxylate (PC) chelators, other than the carbonate ion, in the aqueous medium. The aqueous chemistry of pentavalent uranium species with three environmentally relevant PCs was probed using electrochemical and DFT methods to understand the redox energy and kinetics of conversion of the U(VI)/U(V) couple, stability, structure, stoichiometry, binding modes, etc. Interestingly, pentavalent uranium complexes with PCs are quite persistent over a wide range of pH starting from acidic to alkaline conditions. The PC chelators block the cation-cation interaction (CCI) of U(V) through strong hetero-bidentate chelation and intermolecular hydrogen bonding (IMHB) interactions which stabilize the pentavalent metal ion against disproportionation. For uranyl species in the presence of PCs, acting as chelators, CV plots were obtained at varying pH values from 2 to 8. The obtained results indicate an irreversible single redox peak involving U(VI) to U(V) conversion and association of a coupled chemical reaction with the electron transfer step. ESI-MS studies were performed to understand the speciation effect on the U(VI)/U(V) redox couple with varying pH. Speciation modelling of U(V) with the PC ligands was carried out, which indicated that the U(V) is redox stable in nearly 47% of the pH region in the presence of the PCs as compared to the carboxylate-based chelators. The free energy and reduction potential of the U(V) complexes and the reduction free energy and disproportionation free energy for the U(VI)/U(V) couple were determined by DFT computations in the presence of the PCs. In situ spectroelectrochemical spectra were recorded to provide evidence for the existence of U(V) species with PCs in the aqueous medium and to acquire its absorption spectra. The present study is highly significant for understanding the coordination chemistry of pentavalent uranium species, accurate modelling of uranium, and isolation of U(V).
Collapse
Affiliation(s)
- Ashutosh Srivastava
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai, India-400085.
| | - Sk Musharaf Ali
- Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai, India-400085
| | | | - Sumit Kumar
- Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai, India-400085
| | - Pranaw Kumar
- Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai, India-400085
| | - Neetika Rawat
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai, India-400085.
| | - P K Mohapatra
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai, India-400085.
| |
Collapse
|
3
|
Mulkapuri S, Siddikha A, Ravi A, Saha P, Kumar AV, Boodida S, Vithal M, Das SK. Electrocatalytic Hydrogen Evolution by a Uranium(VI) Polyoxometalate: an Environmental Toxin for Sustainable Energy Generation. Inorg Chem 2023; 62:19664-19676. [PMID: 37967464 DOI: 10.1021/acs.inorgchem.3c03018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
The uranyl ion (UO2)2+, a uranium nuclear waste, is one of the serious contaminants in our ecosystem because of its radioactivity, relevant human activities, and highly mobile and complex nature of living cells. In this article, we have reported the synthesis and structural characterization of an uranyl cation-incorporated polyoxometalate (POM) compound, K10[{K4(H2O)6}{UO2}2(α-PW9O34)2]·13H2O (1), in which the uranyl cations are complexed with an in situ generated [α-PW9O34]9- cluster. Single-crystal X-ray diffraction (SCXRD) analysis of compound 1 reveals that the uranyl-potassium complex cationic species, [{K4(H2O)6}{UO2}2]8+, is sandwiched by two [α-PW9O34]9- clusters resulting in a Dawson type of POM. Compound 1 was further characterized by inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis and infrared (IR), Raman, electronic absorption, and solid-state photoluminescence spectral studies. IR stretching vibrations at 895 and 856 cm-1 and the Raman signature peak at 792 cm-1 in the IR and Raman spectra of compound 1 primarily confirm the presence of a trans-[O═U═O]2+ ion. The solid-state photoluminescence spectrum of 1 exhibits a typical vibronic structure, resulting from symmetrical vibrations of [O═U═O]2+ bands, corresponding to the electronic transitions of S11 → S10 and S10 → S0υ (υ = 0-3). Interestingly, title compound 1 shows efficient electrocatalytic hydrogen evolution by water reduction with low Tafel slope values of 186.59 and 114.83 mV dec-1 at 1 mA cm-2 along with optimal Faradaic efficiency values of 82 and 87% at neutral pH and in acidic pH 3, respectively. Detailed electrochemical analyses reveal that the catalytic hydrogen evolution reaction (HER) activity mediated by compound 1 is associated with the UVI/UV redox couple of the POM. The microscopic as well as routine spectral analyses of postelectrode samples and controlled experiments have confirmed that compound 1 behaves like a true molecular electrocatalyst for the HER. To our knowledge, this is the first paradigm of a uranium-containing polyoxometalate that exhibits electrocatalytic water reduction to molecular H2. In a nutshell, an environmental toxin (a uranium-oxo compound) has been demonstrated to be utilized as an efficient electrocatalyst for hydrogen generation from water, a green approach of sustainable energy production.
Collapse
Affiliation(s)
- Sateesh Mulkapuri
- School of Chemistry, University of Hyderabad, P. O. Central University, Hyderabad 500046, India
| | - Asha Siddikha
- School of Chemistry, University of Hyderabad, P. O. Central University, Hyderabad 500046, India
- Department of Chemistry, JNTUH University College of Engineering, Science and Technology, Hyderabad 500085, India
- Department of Chemistry, Osmania University, Hyderabad 500 007, India
| | - Athira Ravi
- School of Chemistry, University of Hyderabad, P. O. Central University, Hyderabad 500046, India
| | - Pinki Saha
- School of Chemistry, University of Hyderabad, P. O. Central University, Hyderabad 500046, India
| | - Avulu Vinod Kumar
- School of Chemistry, University of Hyderabad, P. O. Central University, Hyderabad 500046, India
| | - Sathyanarayana Boodida
- Department of Chemistry, JNTUH University College of Engineering, Science and Technology, Hyderabad 500085, India
| | - Muga Vithal
- Department of Chemistry, Osmania University, Hyderabad 500 007, India
| | - Samar K Das
- School of Chemistry, University of Hyderabad, P. O. Central University, Hyderabad 500046, India
| |
Collapse
|
4
|
Hilpmann S, Rossberg A, Steudtner R, Drobot B, Hübner R, Bok F, Prieur D, Bauters S, Kvashnina KO, Stumpf T, Cherkouk A. Presence of uranium(V) during uranium(VI) reduction by Desulfosporosinus hippei DSM 8344 T. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 875:162593. [PMID: 36889400 DOI: 10.1016/j.scitotenv.2023.162593] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 02/27/2023] [Accepted: 02/27/2023] [Indexed: 06/18/2023]
Abstract
Microbial U(VI) reduction influences uranium mobility in contaminated subsurface environments and can affect the disposal of high-level radioactive waste by transforming the water-soluble U(VI) to less mobile U(IV). The reduction of U(VI) by the sulfate-reducing bacterium Desulfosporosinus hippei DSM 8344T, a close phylogenetic relative to naturally occurring microorganism present in clay rock and bentonite, was investigated. D. hippei DSM 8344T showed a relatively fast removal of uranium from the supernatants in artificial Opalinus Clay pore water, but no removal in 30 mM bicarbonate solution. Combined speciation calculations and luminescence spectroscopic investigations showed the dependence of U(VI) reduction on the initial U(VI) species. Scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy showed uranium-containing aggregates on the cell surface and some membrane vesicles. By combining different spectroscopic techniques, including UV/Vis spectroscopy, as well as uranium M4-edge X-ray absorption near-edge structure recorded in high-energy-resolution fluorescence-detection mode and extended X-ray absorption fine structure analysis, the partial reduction of U(VI) could be verified, whereby the formed U(IV) product has an unknown structure. Furthermore, the U M4 HERFD-XANES showed the presence of U(V) during the process. These findings offer new insights into U(VI) reduction by sulfate-reducing bacteria and contribute to a comprehensive safety concept for a repository for high-level radioactive waste.
Collapse
Affiliation(s)
- Stephan Hilpmann
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - André Rossberg
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany; Rossendorf Beamline (BM20-ROBL), European Synchrotron Radiation Facility, Grenoble, France
| | - Robin Steudtner
- 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
| | - René Hübner
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Dresden, Germany
| | - Frank Bok
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany
| | - Damien Prieur
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany; Rossendorf Beamline (BM20-ROBL), European Synchrotron Radiation Facility, Grenoble, France
| | - Stephen Bauters
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany; Rossendorf Beamline (BM20-ROBL), European Synchrotron Radiation Facility, Grenoble, France
| | - Kristina O Kvashnina
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328 Dresden, Germany; Rossendorf Beamline (BM20-ROBL), European Synchrotron Radiation Facility, Grenoble, France
| | - 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.
| |
Collapse
|
5
|
Sundararajan M. Redox Potentials of Uranyl Ions in Macrocyclic Complexes: Quantifying the Role of Counter-Ions. ACS OMEGA 2023; 8:18041-18046. [PMID: 37251172 PMCID: PMC10210231 DOI: 10.1021/acsomega.3c01244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/27/2023] [Indexed: 05/31/2023]
Abstract
Several uranyl ions strapped with Schiff-base ligands in the presence of redox-innocent metal ions are synthesized, and their reduction potentials are recently estimated. The change in Lewis acidity of the redox-innocent metal ions contributes to ∼60 mV/pKa unit quantified which is intriguing. Upon increasing the Lewis acidity of metal ions, the number of triflate molecules found near the metal ions also increases whose contributions toward the redox potentials remain poorly understood and not quantified until now. Most importantly, to ease the computational burden, triflate anions are often neglected in quantum chemical models due to their larger size and weak coordination to metal ions. Herein, we have quantified and dissected the individual contributions that arise alone from Lewis acid metal ions and from triflate anions with electronic structure calculations. The triflate anion contributions are large, in particular, for divalent and trivalent anions that cannot be neglected. It was presumed to be innocent, but we here show that they can contribute more than 50% to the predicted redox potentials, suggesting that their vital role in the overall reduction processes cannot be neglected.
Collapse
|
6
|
Molinas M, Meibom KL, Faizova R, Mazzanti M, Bernier-Latmani R. Mechanism of Reduction of Aqueous U(V)-dpaea and Solid-Phase U(VI)-dpaea Complexes: The Role of Multiheme c-Type Cytochromes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:7537-7546. [PMID: 37133831 DOI: 10.1021/acs.est.3c00666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The biological reduction of soluble U(VI) complexes to form immobile U(IV) species has been proposed to remediate contaminated sites. It is well established that multiheme c-type cytochromes (MHCs) are key mediators of electron transfer to aqueous phase U(VI) complexes for bacteria such as Shewanella oneidensis MR-1. Recent studies have confirmed that the reduction proceeds via a first electron transfer forming pentavalent U(V) species that readily disproportionate. However, in the presence of the stabilizing aminocarboxylate ligand, dpaea2- (dpaeaH2═bis(pyridyl-6-methyl-2-carboxylate)-ethylamine), biologically produced U(V) persisted in aqueous solution at pH 7. We aim to pinpoint the role of MHC in the reduction of U(V)-dpaea and to establish the mechanism of solid-phase U(VI)-dpaea reduction. To that end, we investigated U-dpaea reduction by two deletion mutants of S. oneidensis MR-1-one lacking outer membrane MHCs and the other lacking all outer membrane MHCs and a transmembrane MHC-and by the purified outer membrane MHC, MtrC. Our results suggest that solid-phase U(VI)-dpaea is reduced primarily by outer membrane MHCs. Additionally, MtrC can directly transfer electrons to U(V)-dpaea to form U(IV) species but is not strictly necessary, underscoring the primary involvement of outer membrane MHCs in the reduction of this pentavalent U species but not excluding that of periplasmic MHCs.
Collapse
Affiliation(s)
- Margaux Molinas
- Environmental Microbiology Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Karin Lederballe Meibom
- Environmental Microbiology Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Radmila Faizova
- Group of Coordination Chemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Marinella Mazzanti
- Group of Coordination Chemistry, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| | - Rizlan Bernier-Latmani
- Environmental Microbiology Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland
| |
Collapse
|
7
|
Fallon CM, Bower WR, Powell BA, Livens FR, Lyon IC, McNulty AE, Peruski K, Mosselmans JFW, Kaplan DI, Grolimund D, Warnicke P, Ferreira-Sanchez D, Kauppi MS, Vettese GF, Shaw S, Morris K, Law GTW. Vadose-zone alteration of metaschoepite and ceramic UO 2 in Savannah River Site field lysimeters. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 862:160862. [PMID: 36521613 DOI: 10.1016/j.scitotenv.2022.160862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/25/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
Uranium dioxide (UO2) and metaschoepite (UO3•nH2O) particles have been identified as contaminants at nuclear sites. Understanding their behavior and impact is crucial for safe management of radioactively contaminated land and to fully understand U biogeochemistry. The Savannah River Site (SRS) (South Carolina, USA), is one such contaminated site, following historical releases of U-containing wastes to the vadose zone. Here, we present an insight into the behavior of these two particle types under dynamic conditions representative of the SRS, using field lysimeters (15 cm D x 72 cm L). Discrete horizons containing the different particle types were placed at two depths in each lysimeter (25 cm and 50 cm) and exposed to ambient rainfall for 1 year, with an aim of understanding the impact of dynamic, shallow subsurface conditions on U particle behavior and U migration. The dissolution and migration of U from the particle sources and the speciation of U throughout the lysimeters was assessed after 1 year using a combination of sediment digests, sequential extractions, and bulk and μ-focus X-ray spectroscopy. In the UO2 lysimeter, oxidative dissolution of UO2 and subsequent migration of U was observed over 1-2 cm in the direction of waterflow and against it. Sequential extractions of the UO2 sources suggest they were significantly altered over 1 year. The metaschoepite particles also showed significant dissolution with marginally enhanced U migration (several cm) from the sources. However, in both particle systems the released U was quantitively retained in sediment as a range of different U(IV) and U(VI) phases, and no detectable U was measured in the lysimeter effluent. The study provides a useful insight into U particle behavior in representative, real-world conditions relevant to the SRS, and highlights limited U migration from particle sources due to secondary reactions with vadose zone sediments over 1 year.
Collapse
Affiliation(s)
- Connaugh M Fallon
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester M13 9PL, UK,; Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - William R Bower
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester M13 9PL, UK,; Radiochemistry Unit, Department of Chemistry, University of Helsinki, Helsinki 00014, Finland
| | - Brian A Powell
- Department of Environmental Engineering and Earth Sciences, Department of Chemistry, Clemson University, Clemson, SC 29634, USA
| | - Francis R Livens
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester M13 9PL, UK,; Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Ian C Lyon
- Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Alana E McNulty
- Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Kathryn Peruski
- Department of Environmental Engineering and Earth Sciences, Department of Chemistry, Clemson University, Clemson, SC 29634, USA
| | | | - Daniel I Kaplan
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29808, USA
| | - Daniel Grolimund
- Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | - Peter Warnicke
- Swiss Light Source, Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | | | - Marja Siitari Kauppi
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Helsinki 00014, Finland
| | - Gianni F Vettese
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Helsinki 00014, Finland
| | - Samuel Shaw
- Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Katherine Morris
- Research Centre for Radwaste and Decommissioning and Williamson Research Centre, Department of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK
| | - Gareth T W Law
- Radiochemistry Unit, Department of Chemistry, University of Helsinki, Helsinki 00014, Finland.
| |
Collapse
|
8
|
Yin Y, Liu C, Zhao G, Chen Y. Versatile mechanisms and enhanced strategies of pollutants removal mediated by Shewanella oneidensis: A review. JOURNAL OF HAZARDOUS MATERIALS 2022; 440:129703. [PMID: 35963088 DOI: 10.1016/j.jhazmat.2022.129703] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 07/17/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
The removal of environmental pollutants is important for a sustainable ecosystem and human health. Shewanella oneidensis (S. oneidensis) has diverse electron transfer pathways and can use a variety of contaminants as electron acceptors or electron donors. This paper reviews S. oneidensis's function in removing environmental pollutants, including heavy metals, inorganic non-metallic ions (INMIs), and toxic organic pollutants. S. oneidensis can mineralize o-xylene (OX), phenanthrene (PHE), and pyridine (Py) as electron donors, and also reduce azo dyes, nitro aromatic compounds (NACs), heavy metals, and iodate by extracellular electron transfer (EET). For azo dyes, NACs, Cr(VI), nitrite, nitrate, thiosulfate, and sulfite that can cross the membrane, S. oneidensis transfers electrons to intracellular reductases to catalyze their reduction. However, most organic pollutants cannot be directly degraded by S. oneidensis, but S. oneidensis can remove these pollutants by self-synthesizing catalysts or photocatalysts, constructing bio-photocatalytic systems, driving Fenton reactions, forming microbial consortia, and genetic engineering. However, the industrial-scale application of S. oneidensis is insufficient. Future research on the metabolism of S. oneidensis and interfacial reactions with other materials needs to be deepened, and large-scale reactors should be developed that can be used for practical engineering applications.
Collapse
Affiliation(s)
- Yue Yin
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Chao Liu
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Guohua Zhao
- School of Chemical Science and Engineering, Tongji University, Shanghai 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| |
Collapse
|
9
|
Chen S, Cheng Y, Zeng Q, Zhu T, Li F, Lan T, Yang Y, Yang J, Liao J, Liu N. Accurate determination of tetravalent uranium reduced by microorganisms via a potentiometric titration procedure. RADIOCHIM ACTA 2022. [DOI: 10.1515/ract-2022-0037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Although bioreduction induced by microorganisms has been considered to play an important role in the chemical and migration behaviors of uranium in nature, the accurate determination of tetravalent uranium reduced by microorganisms is still difficult to achieve. In this work, potentiometric titration via K2Cr2O7 was used to quantitatively determine the microorganism reduced tetravalent uranium (U(IV)) for the first time. By evaluating the influence of microorganism substance content on the titration of U(IV), the appropriate determination range of U(IV) and biomass was confirmed, and U(IV) induced by bioreduction in three microorganisms was determined. With this method, U(IV) of more than 0.12 mg in microorganisms can be quantitatively measured with an accuracy of 2.2% and a precision of 1.3%, which has been established with the premise that the pretreatment biomass and quantity of U(IV) are in an appropriate range. Compared with the estimated values via the changes in hexavalent uranium (U(VI)) concentration in the bioreduction system, the results obtained by this method can more accurately reflect the quantity of U(IV) in microorganisms. This work can help us to better understand the bioreduction behavior of uranium in the environment.
Collapse
Affiliation(s)
- Shunzhang Chen
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Yanxia Cheng
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Qian Zeng
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Ting Zhu
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Feize Li
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Tu Lan
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Yuanyou Yang
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Jijun Yang
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Jiali Liao
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| | - Ning Liu
- Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China
| |
Collapse
|
10
|
Arumugam K, Burton NA. Disproportionation of the Uranyl(V) Coordination Complexes in Aqueous Solution through Outer-Sphere Electron Transfer. Inorg Chem 2021; 60:18832-18842. [PMID: 34847326 DOI: 10.1021/acs.inorgchem.1c02575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Among the linear actinyl(VI/V) cations, the uranyl(V) species are particularly intriguing because they are unstable and exhibit a unique behavior to undergo H+ promoted disproportionation in aqueous solution and form stable uranyl(VI) and U(IV) complexes. This study uses density functional theory (DFT) combined with the conductor-like polarizable continuum model approach to investigate [UO2]2+/+ to [UIVO2] reduction free energies (RFEs) and explores the stability of uranyl(V) complexes in aqueous solution through computing disproportionation free energies (DFEs) for an outer-sphere electron transfer process. In addition to the aqua complex (U1), another three commonly encountered ligands such as chloride (U2), acetate (U3), and carbonate (U4) in aqueous environmental conditions are taken into account. For the U1 complex, the computed 1e- (V/IV) and 2e- (VI/IV) RFEs are in good agreement with experiments. The computed DFEs reveal that the presence of H+ is imperative for the disproportionation to take place. Although the presence of the alkali cations favors the disproportionation to some extent, they cannot fully make the reaction thermodynamically feasible. For the anionic complexes, the high negative charge does not allow for the formation of a cation-cation encounter complex due to Coulombic repulsion. Furthermore, an additional factor is the ligand exchange reaction which is also an energy-demanding step. Therefore, the current study examined the Kern-Orlemann mechanism and our results validate the mechanism based on DFT computed DFEs and propose that for the anionic complexes, an outer-sphere electron transfer is highly probable and our computed protonation free energies further support this claim.
Collapse
Affiliation(s)
- Krishnamoorthy Arumugam
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| | - Neil A Burton
- Department of Chemistry, School of Natural Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K
| |
Collapse
|
11
|
You W, Peng W, Tian Z, Zheng M. Uranium bioremediation with U(VI)-reducing bacteria. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 798:149107. [PMID: 34325147 DOI: 10.1016/j.scitotenv.2021.149107] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
Uranium (U) pollution is an environmental hazard caused by the development of the nuclear industry. Microbial reduction of hexavalent uranium (U(VI)) to tetravalent uranium (U(IV)) reduces U solubility and mobility and has been proposed as an effective method to remediate uranium contamination. In this review, U(VI) remediation with respect to U(VI)-reducing bacteria, mechanisms, influencing factors, products, and reoxidation are systematically summarized. Reportedly, some metal- and sulfate-reducing bacteria possess excellent U(VI) reduction capability through mechanisms involving c-type cytochromes, extracellular pili, electron shuttle, or thioredoxin reduction. In situ remediation has been demonstrated as an ideal strategy for large-scale degradation of uranium contaminants than ex situ. However, U(VI) reduction efficiency can be affected by various factors, including pH, temperature, bicarbonate, electron donors, and coexisting metal ions. Furthermore, it is noteworthy that the reduction products could be reoxidized when exposed to oxygen and nitrate, inevitably compromising the remediation effects, especially for non-crystalline U(IV) with weak stability.
Collapse
Affiliation(s)
- Wenbo You
- Key Laboratory of Regional Energy Systems Optimization, Ministry of Education, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
| | - Wanting Peng
- Key Laboratory of Regional Energy Systems Optimization, Ministry of Education, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
| | - Zhichao Tian
- Key Laboratory of Regional Energy Systems Optimization, Ministry of Education, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China
| | - Maosheng Zheng
- Key Laboratory of Regional Energy Systems Optimization, Ministry of Education, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China.
| |
Collapse
|
12
|
Townsend LT, Kuippers G, Lloyd JR, Natrajan LS, Boothman C, Mosselmans JFW, Shaw S, Morris K. Biogenic Sulfidation of U(VI) and Ferrihydrite Mediated by Sulfate-Reducing Bacteria at Elevated pH. ACS EARTH & SPACE CHEMISTRY 2021; 5:3075-3086. [PMID: 34825123 PMCID: PMC8607498 DOI: 10.1021/acsearthspacechem.1c00126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/17/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Globally, the need for radioactive waste disposal and contaminated land management is clear. Here, gaining an improved understanding of how biogeochemical processes, such as Fe(III) and sulfate reduction, may control the environmental mobility of radionuclides is important. Uranium (U), typically the most abundant radionuclide by mass in radioactive wastes and contaminated land scenarios, may have its environmental mobility impacted by biogeochemical processes within the subsurface. This study investigated the fate of U(VI) in an alkaline (pH ∼9.6) sulfate-reducing enrichment culture obtained from a high-pH environment. To explore the mobility of U(VI) under alkaline conditions where iron minerals are ubiquitous, a range of conditions were tested, including high (30 mM) and low (1 mM) carbonate concentrations and the presence and absence of Fe(III). At high carbonate concentrations, the pH was buffered to approximately pH 9.6, which delayed the onset of sulfate reduction and meant that the reduction of U(VI)(aq) to poorly soluble U(IV)(s) was slowed. Low carbonate conditions allowed microbial sulfate reduction to proceed and caused the pH to fall to ∼7.5. This drop in pH was likely due to the presence of volatile fatty acids from the microbial respiration of gluconate. Here, aqueous sulfide accumulated and U was removed from solution as a mixture of U(IV) and U(VI) phosphate species. In addition, sulfate-reducing bacteria, such as Desulfosporosinus species, were enriched during development of sulfate-reducing conditions. Results highlight the impact of carbonate concentrations on U speciation and solubility in alkaline conditions, informing intermediate-level radioactive waste disposal and radioactively contaminated land management.
Collapse
Affiliation(s)
- Luke T. Townsend
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| | - Gina Kuippers
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| | - Jonathan R. Lloyd
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| | - Louise S. Natrajan
- Centre
for Radiochemistry Research, Department of Chemistry, School of Natural
Sciences, The University of Manchester, Manchester M13 9PL, U.K.
| | - Christopher Boothman
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| | - J. Frederick W. Mosselmans
- Diamond
Light Source Ltd., Diamond
House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K.
| | - Samuel Shaw
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| | - Katherine Morris
- Research
Centre for Radwaste Disposal and Williamson Research Centre for Molecular
Environmental Science, Department of Earth and Environmental Sciences,
School of Natural Sciences, The University
of Manchester, Manchester M13 9PL, U.K.
| |
Collapse
|
13
|
Evidence for ligand- and solvent-induced disproportionation of uranium(IV). Nat Commun 2021; 12:4832. [PMID: 34376682 PMCID: PMC8355312 DOI: 10.1038/s41467-021-25151-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/21/2021] [Indexed: 11/08/2022] Open
Abstract
Disproportionation, where a chemical element converts its oxidation state to two different ones, one higher and one lower, underpins the fundamental chemistry of metal ions. The overwhelming majority of uranium disproportionations involve uranium(III) and (V), with a singular example of uranium(IV) to uranium(V/III) disproportionation known, involving a nitride to imido/triflate transformation. Here, we report a conceptually opposite disproportionation of uranium(IV)-imido complexes to uranium(V)-nitride/uranium(III)-amide mixtures. This is facilitated by benzene, but not toluene, since benzene engages in a redox reaction with the uranium(III)-amide product to give uranium(IV)-amide and reduced arene. These disproportionations occur with potassium, rubidium, and cesium counter cations, but not lithium or sodium, reflecting the stability of the corresponding alkali metal-arene by-products. This reveals an exceptional level of ligand- and solvent-control over a key thermodynamic property of uranium, and is complementary to isolobal uranium(V)-oxo disproportionations, suggesting a potentially wider prevalence possibly with broad implications for the chemistry of uranium.
Collapse
|
14
|
Townsend LT, Morris K, Harrison R, Schacherl B, Vitova T, Kovarik L, Pearce CI, Mosselmans JFW, Shaw S. Sulfidation of magnetite with incorporated uranium. CHEMOSPHERE 2021; 276:130117. [PMID: 34088087 DOI: 10.1016/j.chemosphere.2021.130117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 02/03/2021] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
Uranium (U) is a radionuclide of key environmental interest due its abundance by mass within radioactive waste and presence in contaminated land scenarios. Ubiquitously present iron (oxyhydr)oxide mineral phases, such as (nano)magnetite, have been identified as candidates for immobilisation of U via incorporation into the mineral structure. Studies of how biogeochemical processes, such as sulfidation from the presence of sulfate-reducing bacteria, may affect iron (oxyhydr)oxides and impact radionuclide mobility are important in order to underpin geological disposal of radioactive waste and manage radioactively contaminated land. Here, this study utilised a highly controlled abiotic method for sulfidation of U(V) incorporated into nanomagnetite to determine the fate and speciation of U. Upon sulfidation, transient release of U into solution occurred (∼8.6% total U) for up to 3 days, despite the highly reducing conditions. As the system evolved, lepidocrocite was observed to form over a period of days to weeks. After 10 months, XAS and geochemical data showed all U was partitioned to the solid phase, as both nanoparticulate uraninite (U(IV)O2) and a percentage of retained U(V). Further EXAFS analysis showed incorporation of the residual U(V) fraction into an iron (oxyhydr)oxide mineral phase, likely nanomagnetite or lepidocrocite. Overall, these results provide new insights into the stability of U(V) incorporated iron (oxyhydr)oxides during sulfidation, confirming the longer term retention of U in the solid phase under complex, environmentally relevant conditions.
Collapse
Affiliation(s)
- Luke T Townsend
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Katherine Morris
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Robert Harrison
- School of Mechanical, Aerospace & Civil Engineering, University of Manchester, Manchester, M13 9PL, UK
| | - Bianca Schacherl
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), P.O. Box 3640, D-76021, Karlsruhe, Germany
| | - Tonya Vitova
- Karlsruhe Institute of Technology, Institute for Nuclear Waste Disposal (KIT-INE), P.O. Box 3640, D-76021, Karlsruhe, Germany
| | - Libor Kovarik
- Pacific Northwest National Laboratory, Richland, WA, 99352, United States
| | - Carolyn I Pearce
- Pacific Northwest National Laboratory, Richland, WA, 99352, United States
| | - J Frederick W Mosselmans
- Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK
| | - Samuel Shaw
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK.
| |
Collapse
|
15
|
Hanson A, Nizinski CA, McDonald LW. Effect of Diel Cycling Temperature, Relative Humidity, and Synthetic Route on the Surface Morphology and Hydrolysis of α-U 3O 8. ACS OMEGA 2021; 6:18426-18433. [PMID: 34308073 PMCID: PMC8296549 DOI: 10.1021/acsomega.1c02487] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
The speciation and morphological changes of α-U3O8 following aging under diel cycling temperature and relative humidity (RH) have been examined. This work advances the knowledge of U-oxide hydration as a result of synthetic route and environmental conditions, ultimately giving novel insight into nuclear material provenance. α-U3O8 was synthesized via the washed uranyl peroxide (UO4) and ammonium uranyl carbonate (AUC) synthetic routes to produce unaged starting materials with different morphologies. α-U3O8 from UO4 is comprised of subrounded particles, while α-U3O8 from AUC contains blocky, porous particles approximately an order of magnitude larger than particles from UO4. For aging, a humidity chamber was programmed for continuous daily cycles of 12 "high" hours of 45 °C and 90% RH, and 12 "low" hours of 25 °C and 20% RH. Samples were analyzed at varying intervals of 14, 24, 36, 43, and 54 days. At each aging interval, crystallographic changes were measured via powder X-ray diffraction coupled with whole pattern fitting for quantitative analysis. Morphologic effects were studied via scanning electron microscopy and 12-way classification via machine learning. While all samples were found to have distinguishing morphologic characteristics (93.2% classification accuracy), α-U3O8 from UO4 had more apparent change with increasing aging time. Nonetheless, α-U3O8 from AUC was found to hydrate more quickly than α-U3O8 from UO4, which can likely be attributed to its larger surface area and porous starting material morphology.
Collapse
|
16
|
Molinas M, Faizova R, Brown A, Galanzew J, Schacherl B, Bartova B, Meibom KL, Vitova T, Mazzanti M, Bernier-Latmani R. Biological Reduction of a U(V)-Organic Ligand Complex. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:4753-4761. [PMID: 33705103 PMCID: PMC8154365 DOI: 10.1021/acs.est.0c06633] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 02/24/2021] [Accepted: 03/01/2021] [Indexed: 05/20/2023]
Abstract
Metal-reducing microorganisms such as Shewanella oneidensis MR-1 reduce highly soluble species of hexavalent uranyl (U(VI)) to less mobile tetravalent uranium (U(IV)) compounds. The biologically mediated immobilization of U(VI) is being considered for the remediation of U contamination. However, the mechanistic underpinnings of biological U(VI) reduction remain unresolved. It has become clear that a first electron transfer occurs to form pentavalent (U(V)) intermediates, but it has not been definitively established whether a second one-electron transfer can occur or if disproportionation of U(V) is required. Here, we utilize the unusual properties of dpaea2- ((dpaeaH2═bis(pyridyl-6-methyl-2-carboxylate)-ethylamine)), a ligand forming a stable soluble aqueous complex with U(V), and investigate the reduction of U(VI)-dpaea and U(V)-dpaea by S. oneidensis MR-1. We establish U speciation through time by separating U(VI) from U(IV) by ion exchange chromatography and characterize the reaction end-products using U M4-edge high resolution X-ray absorption near-edge structure (HR-XANES) spectroscopy. We document the reduction of solid phase U(VI)-dpaea to aqueous U(V)-dpaea but, most importantly, demonstrate that of U(V)-dpaea to U(IV). This work establishes the potential for biological reduction of U(V) bound to a stabilizing ligand. Thus, further work is warranted to investigate the possible persistence of U(V)-organic complexes followed by their bioreduction in environmental systems.
Collapse
Affiliation(s)
- Margaux Molinas
- Environmental
Microbiology Laboratory, and Group of Coordination Chemistry, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Lausanne 1015, Switzerland
| | - Radmila Faizova
- Environmental
Microbiology Laboratory, and Group of Coordination Chemistry, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Lausanne 1015, Switzerland
| | - Ashley Brown
- Environmental
Microbiology Laboratory, and Group of Coordination Chemistry, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Lausanne 1015, Switzerland
| | - Jurij Galanzew
- Karlsruhe
Institute of Technology (KIT), Institute for Nuclear Waste Disposal
(INE), P.O. 3640, D-76021Karlsruhe, Germany
| | - Bianca Schacherl
- Karlsruhe
Institute of Technology (KIT), Institute for Nuclear Waste Disposal
(INE), P.O. 3640, D-76021Karlsruhe, Germany
| | - Barbora Bartova
- Environmental
Microbiology Laboratory, and Group of Coordination Chemistry, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Lausanne 1015, Switzerland
| | - Karin L. Meibom
- Environmental
Microbiology Laboratory, and Group of Coordination Chemistry, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Lausanne 1015, Switzerland
| | - Tonya Vitova
- Karlsruhe
Institute of Technology (KIT), Institute for Nuclear Waste Disposal
(INE), P.O. 3640, D-76021Karlsruhe, Germany
| | - Marinella Mazzanti
- Environmental
Microbiology Laboratory, and Group of Coordination Chemistry, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Lausanne 1015, Switzerland
| | - Rizlan Bernier-Latmani
- Environmental
Microbiology Laboratory, and Group of Coordination Chemistry, Ecole Polytechnique Fédérale de Lausanne
(EPFL), Lausanne 1015, Switzerland
| |
Collapse
|
17
|
Faizova R, Fadaei‐Tirani F, Chauvin A, Mazzanti M. Synthesis and Characterization of Water Stable Uranyl(V) Complexes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Radmila Faizova
- Institut des Sciences et Ingénierie Chimiques Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Farzaneh Fadaei‐Tirani
- Institut des Sciences et Ingénierie Chimiques Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Anne‐Sophie Chauvin
- Institut des Sciences et Ingénierie Chimiques Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Marinella Mazzanti
- Institut des Sciences et Ingénierie Chimiques Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| |
Collapse
|
18
|
Faizova R, Fadaei‐Tirani F, Chauvin A, Mazzanti M. Synthesis and Characterization of Water Stable Uranyl(V) Complexes. Angew Chem Int Ed Engl 2021; 60:8227-8235. [DOI: 10.1002/anie.202016123] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/04/2021] [Indexed: 12/13/2022]
Affiliation(s)
- Radmila Faizova
- Institut des Sciences et Ingénierie Chimiques Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Farzaneh Fadaei‐Tirani
- Institut des Sciences et Ingénierie Chimiques Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Anne‐Sophie Chauvin
- Institut des Sciences et Ingénierie Chimiques Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Marinella Mazzanti
- Institut des Sciences et Ingénierie Chimiques Ecole Polytechnique Fédérale de Lausanne (EPFL) 1015 Lausanne Switzerland
| |
Collapse
|
19
|
Gerber E, Romanchuk AY, Weiss S, Bauters S, Schacherl B, Vitova T, Hübner R, Shams Aldin Azzam S, Detollenaere D, Banerjee D, Butorin SM, Kalmykov SN, Kvashnina KO. Insight into the structure–property relationship of UO 2 nanoparticles. Inorg Chem Front 2021. [DOI: 10.1039/d0qi01140a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We show that the structural and electronic properties of UO2 NPs (2–3 nm) are similar to those of bulk UO2 under inert conditions, with U(iv) as the dominating oxidation state, though NPs oxidize with time and under the X-ray beam.
Collapse
|
20
|
Behera N, Sethi S. Unprecedented Catalytic Behavior of Uranyl(VI) Compounds in Chemical Reactions. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000611] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Nabakrushna Behera
- School of Chemistry Sambalpur University Jyoti Vihar – 768019 Sambalpur Odisha India
| | - Sipun Sethi
- School of Chemistry Sambalpur University Jyoti Vihar – 768019 Sambalpur Odisha India
| |
Collapse
|
21
|
Fuller AJ, Leary P, Gray ND, Davies HS, Mosselmans JFW, Cox F, Robinson CH, Pittman JK, McCann CM, Muir M, Graham MC, Utsunomiya S, Bower WR, Morris K, Shaw S, Bots P, Livens FR, Law GTW. Organic complexation of U(VI) in reducing soils at a natural analogue site: Implications for uranium transport. CHEMOSPHERE 2020; 254:126859. [PMID: 32957279 DOI: 10.1016/j.chemosphere.2020.126859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/07/2020] [Accepted: 04/19/2020] [Indexed: 06/11/2023]
Abstract
Understanding the long-term fate, stability, and bioavailability of uranium (U) in the environment is important for the management of nuclear legacy sites and radioactive wastes. Analysis of U behavior at natural analogue sites permits evaluation of U biogeochemistry under conditions more representative of long-term equilibrium. Here, we have used bulk geochemical and microbial community analysis of soils, coupled with X-ray absorption spectroscopy and μ-focus X-ray fluorescence mapping, to gain a mechanistic understanding of the fate of U transported into an organic-rich soil from a pitchblende vein at the UK Needle's Eye Natural Analogue site. U is highly enriched in the Needle's Eye soils (∼1600 mg kg-1). We show that this enrichment is largely controlled by U(VI) complexation with soil organic matter and not U(VI) bioreduction. Instead, organic-associated U(VI) seems to remain stable under microbially-mediated Fe(III)-reducing conditions. U(IV) (as non-crystalline U(IV)) was only observed at greater depths at the site (>25 cm); the soil here was comparatively mineral-rich, organic-poor, and sulfate-reducing/methanogenic. Furthermore, nanocrystalline UO2, an alternative product of U(VI) reduction in soils, was not observed at the site, and U did not appear to be associated with Fe-bearing minerals. Organic-rich soils appear to have the potential to impede U groundwater transport, irrespective of ambient redox conditions.
Collapse
Affiliation(s)
- Adam J Fuller
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK
| | - Peter Leary
- School of Natural and Environmental Sciences, Newcastle University, Newcastle, NE1 7RU, UK
| | - Neil D Gray
- School of Natural and Environmental Sciences, Newcastle University, Newcastle, NE1 7RU, UK
| | - Helena S Davies
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | | | - Filipa Cox
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Clare H Robinson
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Jon K Pittman
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Clare M McCann
- School of Natural and Environmental Sciences, Newcastle University, Newcastle, NE1 7RU, UK
| | - Michael Muir
- School of Geoscience, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Margaret C Graham
- School of Geoscience, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Satoshi Utsunomiya
- School of Chemistry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - William R Bower
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK; Radiochemistry Unit, Department of Chemistry, The University of Helsinki, 00014, Finland
| | - Katherine Morris
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Samuel Shaw
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Pieter Bots
- Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Francis R Livens
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK; Research Centre for Radwaste Disposal, and Williamson Centre for Molecular Environmental Science, Department of Earth and Environmental Sciences, The University of Manchester, Manchester, M13 9PL, UK
| | - Gareth T W Law
- Centre for Radiochemistry Research, Department of Chemistry, The University of Manchester, Manchester, M13 9PL, UK; Radiochemistry Unit, Department of Chemistry, The University of Helsinki, 00014, Finland.
| |
Collapse
|
22
|
Pan Z, Bártová B, LaGrange T, Butorin SM, Hyatt NC, Stennett MC, Kvashnina KO, Bernier-Latmani R. Nanoscale mechanism of UO 2 formation through uranium reduction by magnetite. Nat Commun 2020; 11:4001. [PMID: 32778661 PMCID: PMC7417540 DOI: 10.1038/s41467-020-17795-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 07/14/2020] [Indexed: 11/10/2022] Open
Abstract
Uranium (U) is a ubiquitous element in the Earth's crust at ~2 ppm. In anoxic environments, soluble hexavalent uranium (U(VI)) is reduced and immobilized. The underlying reduction mechanism is unknown but likely of critical importance to explain the geochemical behavior of U. Here, we tackle the mechanism of reduction of U(VI) by the mixed-valence iron oxide, magnetite. Through high-end spectroscopic and microscopic tools, we demonstrate that the reduction proceeds first through surface-associated U(VI) to form pentavalent U, U(V). U(V) persists on the surface of magnetite and is further reduced to tetravalent UO2 as nanocrystals (~1-2 nm) with random orientations inside nanowires. Through nanoparticle re-orientation and coalescence, the nanowires collapse into ordered UO2 nanoclusters. This work provides evidence for a transient U nanowire structure that may have implications for uranium isotope fractionation as well as for the molecular-scale understanding of nuclear waste temporal evolution and the reductive remediation of uranium contamination.
Collapse
Affiliation(s)
- Zezhen Pan
- Environmental Microbiology Laboratory, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Barbora Bártová
- Environmental Microbiology Laboratory, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
- Interdisciplinary Center for Electron Microscopy, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Thomas LaGrange
- Laboratory for Ultrafast Microscopy and Electron Scattering, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Sergei M Butorin
- Molecular and Condensed Matter Physics, Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20, Uppsala, Sweden
| | | | | | - Kristina O Kvashnina
- The Rossendorf Beamline at ESRF - The European Synchrotron, CS40220, 38043, Grenoble, Cedex 9, France
- Helmholtz Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology, PO Box 510119, 01314, Dresden, Germany
| | - Rizlan Bernier-Latmani
- Environmental Microbiology Laboratory, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.
| |
Collapse
|
23
|
Faizova R, Fadaei‐Tirani F, Bernier‐Latmani R, Mazzanti M. Ligand‐Supported Facile Conversion of Uranyl(VI) into Uranium(IV) in Organic and Aqueous Media. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201916334] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Radmila Faizova
- Institute of Chemical Sciences and EngineeringSwiss Federal Institute of Technology Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Farzaneh Fadaei‐Tirani
- Institute of Chemical Sciences and EngineeringSwiss Federal Institute of Technology Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Rizlan Bernier‐Latmani
- School of Architecture, Civil and Environmental EngineeringEPFL 1015 Lausanne Switzerland
| | - Marinella Mazzanti
- Institute of Chemical Sciences and EngineeringSwiss Federal Institute of Technology Lausanne (EPFL) 1015 Lausanne Switzerland
| |
Collapse
|
24
|
Faizova R, Fadaei-Tirani F, Bernier-Latmani R, Mazzanti M. Ligand-Supported Facile Conversion of Uranyl(VI) into Uranium(IV) in Organic and Aqueous Media. Angew Chem Int Ed Engl 2020; 59:6756-6759. [PMID: 32017361 DOI: 10.1002/anie.201916334] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Indexed: 11/11/2022]
Abstract
Reduction of uranyl(VI) to UV and to UIV is important in uranium environmental migration and remediation processes. The anaerobic reduction of a uranyl UVI complex supported by a picolinate ligand in both organic and aqueous media is presented. The [UVI O2 (dpaea)] complex is readily converted into the cis-boroxide UIV species via diborane-mediated reductive functionalization in organic media. Remarkably, in aqueous media the uranyl(VI) complex is rapidly converted, by Na2 S2 O4 , a reductant relevant for chemical remediation processes, into the stable uranyl(V) analogue, which is then slowly reduced to yield a water-insoluble trinuclear UIV oxo-hydroxo cluster. This report provides the first example of direct conversion of a uranyl(VI) compound into a well-defined molecular UIV species in aqueous conditions.
Collapse
Affiliation(s)
- Radmila Faizova
- Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Farzaneh Fadaei-Tirani
- Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Rizlan Bernier-Latmani
- School of Architecture, Civil and Environmental Engineering, EPFL, 1015, Lausanne, Switzerland
| | - Marinella Mazzanti
- Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology Lausanne (EPFL), 1015, Lausanne, Switzerland
| |
Collapse
|
25
|
Vettese GF, Morris K, Natrajan LS, Shaw S, Vitova T, Galanzew J, Jones DL, Lloyd JR. Multiple Lines of Evidence Identify U(V) as a Key Intermediate during U(VI) Reduction by Shewanella oneidensis MR1. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:2268-2276. [PMID: 31934763 DOI: 10.1021/acs.est.9b05285] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
As the dominant radionuclide by mass in many radioactive wastes, the control of uranium mobility in contaminated environments is of high concern. U speciation can be governed by microbial interactions, whereby metal-reducing bacteria are able to reduce soluble U(VI) to insoluble U(IV), providing a method for removal of U from contaminated groundwater. Although microbial U(VI) reduction is widely reported, the mechanism(s) for the transformation of U(VI) to relatively insoluble U(IV) phases are poorly understood. By combining a suite of analyses, including luminescence, U M4-edge high-energy resolved fluorescence detection-X-ray absorption near-edge structure (XANES), and U L3-edge XANES/extended X-ray absorption fine structure, we show that the microbial reduction of U(VI) by the model Fe(III)-reducing bacterium, Shewanella oneidensis MR1, proceeds via a single electron transfer to form a pentavalent U(V) intermediate which disproportionates to form U(VI) and U(IV). Furthermore, we have identified significant U(V) present in post reduction solid phases, implying that U(V) may be stabilized for up to 120.5 h.
Collapse
Affiliation(s)
- Gianni F Vettese
- Williamson Research Centre for Molecular Environmental Science and Research Centre for Radwaste Disposal, Department of Earth and Environmental Science, School of Natural Sciences , The University of Manchester , Oxford Road , Manchester M13 9PL , England
| | - Katherine Morris
- Williamson Research Centre for Molecular Environmental Science and Research Centre for Radwaste Disposal, Department of Earth and Environmental Science, School of Natural Sciences , The University of Manchester , Oxford Road , Manchester M13 9PL , England
| | - Louise S Natrajan
- Centre for Radiochemistry Research, Department of Chemistry, School of Natural Sciences , The University of Manchester , Oxford Road , Manchester M13 9PL , England
| | - Samuel Shaw
- Williamson Research Centre for Molecular Environmental Science and Research Centre for Radwaste Disposal, Department of Earth and Environmental Science, School of Natural Sciences , The University of Manchester , Oxford Road , Manchester M13 9PL , England
| | - Tonya Vitova
- Institute for Nuclear Waste Disposal (INE) , Karlsruhe Institute of Technology , Karlsruhe 76131 , Germany
| | - Jurij Galanzew
- Institute for Nuclear Waste Disposal (INE) , Karlsruhe Institute of Technology , Karlsruhe 76131 , Germany
| | - Debbie L Jones
- College of Environmental Sciences and Engineering , Bangor University , Bangor LL57 2DG , U.K
| | - Jonathan R Lloyd
- Williamson Research Centre for Molecular Environmental Science and Research Centre for Radwaste Disposal, Department of Earth and Environmental Science, School of Natural Sciences , The University of Manchester , Oxford Road , Manchester M13 9PL , England
| |
Collapse
|
26
|
Niklas JE, Hunter KM, Gorden AEV. Bonding Interactions in Uranyl α-Diimine Complexes: A Spectroscopic and Electrochemical Study of the Impacts of Ligand Electronics and Extended Conjugation. Inorg Chem 2019; 58:15088-15100. [PMID: 31689099 DOI: 10.1021/acs.inorgchem.9b01695] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Uranyl complexes of aryl-substituted α-diimine ligands gbha (UO2-1a-f) and phen-BIAN (UO2-2a-f) [gbha (1) = glyoxal bis(2-hydroxyanil); phen-BIAN (2) = N,N'-bis(iminophenol)acenaphthene; R = OMe (a), t-bu (b), H (c), Me (d), F (e), and naphthyl (f)] were designed, prepared, and characterized by X-ray diffraction, FT-IR, NMR, UV-vis, and electrochemical methods. These ligand frameworks contain a salen-type O-N-N-O binding pocket but are redox-noninnocent, leading to unusual metal complex behaviors. Here, we describe three solid-state structures of uranyl complexes UO2-1b, UO2-1c, and UO2-1f and observe manifestations of ligand noninnocence for the U(VI) complexes UO2-1b and UO2-1c. The impacts of accessible π-systems and ligand substitution on the axial uranium-oxo interactions were evaluated spectroscopically via the intraligand charge-transfer (ILCT) processes that dominate the absorption spectra of these complexes and through changes to the asymmetric (ν3) O═U═O stretching frequency. This, in combination with electrochemical data, reveals the effects of the inclusion of the conjugated acenaphthene backbone and the importance of ligand electronic structure on uranyl's bonding interactions.
Collapse
Affiliation(s)
- Julie E Niklas
- Department of Chemistry and Biochemistry , Auburn University , 179 Chemistry Building , Auburn , Alabama 36849 , United States
| | - Katherine M Hunter
- Department of Chemistry and Biochemistry , Auburn University , 179 Chemistry Building , Auburn , Alabama 36849 , United States
| | - Anne E V Gorden
- Department of Chemistry and Biochemistry , Auburn University , 179 Chemistry Building , Auburn , Alabama 36849 , United States
| |
Collapse
|
27
|
Wang Q, Zhu C, Huang X, Yang G. Abiotic reduction of uranium(VI) with humic acid at mineral surfaces: Competing mechanisms, ligand and substituent effects, and electronic structure and vibrational properties. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 254:113110. [PMID: 31479808 DOI: 10.1016/j.envpol.2019.113110] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 07/30/2019] [Accepted: 08/23/2019] [Indexed: 06/10/2023]
Abstract
Abiotic reduction represents an attractive technology to control U(VI) contamination. In this work, an abiotic route of U(VI) reduction with humic acid at mineral surfaces is proposed and reaction mechanisms are addressed by periodic density functional theory calculations. Different influencing factors such as ligand effect, content of CO32- ligands and substituent effect are inspected. The coordination chemistry of uranyl(VI) surface complexes relies strongly on substrates and ligands, and the calculated results are in good agreements with experimental observations available. For the OH- ligand, two competitive mechanisms co-exist that respectively produce the U(IV) and U(V) species, and the former is significantly preferred because of lower energy barriers. Instead, the NO3- ligand leads to the formation of U(V) while for the Cl- ligand, the U(VI) surface complex remains very stable and is not likely to be reduced because of very high energy barriers. The U(V) and U(IV) complexes are the predominant products for low and high CO32- contents, respectively. Accordingly, the abiotic reduction processes with humic acid are efficient to manage U(VI) contamination and become preferred under basic conditions or at higher CO32- contents. The U(VI) reduction is further promoted by introduction of electron-donating rather than electron-withdrawing substituents to humic acid. Electronic structure analyses and vibrational frequency assignments are calculated for the various uranium surface complexes of the reduction processes, serving as a guide for future experimental and engineered studies. The molecular-level understanding given in this work offers an abiotic route for efficient reduction of U(VI) and remediation of U(VI)-contaminated sites at ambient conditions.
Collapse
Affiliation(s)
- Qian Wang
- College of Resources and Environment & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Chang Zhu
- College of Resources and Environment & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Xiaoxiao Huang
- College of Resources and Environment & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China
| | - Gang Yang
- College of Resources and Environment & Chongqing Key Laboratory of Soil Multi-scale Interfacial Process, Southwest University, Chongqing 400715, China.
| |
Collapse
|
28
|
Bower WR, Morris K, Livens FR, Mosselmans JFW, Fallon CM, Fuller AJ, Natrajan L, Boothman C, Lloyd JR, Utsunomiya S, Grolimund D, Ferreira Sanchez D, Jilbert T, Parker J, Neill TS, Law GTW. Metaschoepite Dissolution in Sediment Column Systems-Implications for Uranium Speciation and Transport. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:9915-9925. [PMID: 31317743 DOI: 10.1021/acs.est.9b02292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Metaschoepite is commonly found in U-contaminated environments and metaschoepite-bearing wastes may be managed via shallow or deep disposal. Understanding metaschoepite dissolution and tracking the fate of any liberated U is thus important. Here, discrete horizons of metaschoepite (UO3·nH2O) particles were emplaced in flowing sediment/groundwater columns representative of the UK Sellafield Ltd. site. The column systems either remained oxic or became anoxic due to electron donor additions, and the columns were sacrificed after 6- and 12-months for analysis. Solution chemistry, extractions, and bulk and micro/nano-focus X-ray spectroscopies were used to track changes in U distribution and behavior. In the oxic columns, U migration was extensive, with UO22+ identified in effluents after 6-months of reaction using fluorescence spectroscopy. Unusually, in the electron-donor amended columns, during microbially mediated sulfate reduction, significant amounts of UO2-like colloids (>60% of the added U) were found in the effluents using TEM. XAS analysis of the U remaining associated with the reduced sediments confirmed the presence of trace U(VI), noncrystalline U(IV), and biogenic UO2, with UO2 becoming more dominant with time. This study highlights the potential for U(IV) colloid production from U(VI) solids under reducing conditions and the complexity of U biogeochemistry in dynamic systems.
Collapse
Affiliation(s)
- William R Bower
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
- Radiochemistry Unit, Department of Chemistry , The University of Helsinki , Helsinki , Finland , 00014
| | - Katherine Morris
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Francis R Livens
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
| | | | - Connaugh M Fallon
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
- Radiochemistry Unit, Department of Chemistry , The University of Helsinki , Helsinki , Finland , 00014
| | - Adam J Fuller
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Louise Natrajan
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Christopher Boothman
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Jonathan R Lloyd
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Satoshi Utsunomiya
- Kyushu University , Department of Chemistry , 744 Motooka , Nishi-ku , Fukuoka Japan , 819-0395
| | - Daniel Grolimund
- Swiss Light Source , Paul Scherrer Institute , Villigen , Switzerland , 5232
| | | | - Tom Jilbert
- Ecosystems and Environmental Research Programme, Faculty of Biological and Environmental Sciences , The University of Helsinki , Helsinki , Finland , 00014
| | - Julia Parker
- Diamond Light Source , Harwell Science and Innovation Campus , Didcot , U.K. , OX11 0DE
| | - Thomas S Neill
- Research Centre for Radwaste Disposal and Williamson Research Centre, School of Earth and Environmental Sciences , The University of Manchester , Manchester , U.K. , M13 9PL
| | - Gareth T W Law
- Centre for Radiochemistry Research, School of Chemistry , The University of Manchester , Manchester , U.K. , M13 9PL
- Radiochemistry Unit, Department of Chemistry , The University of Helsinki , Helsinki , Finland , 00014
| |
Collapse
|
29
|
Cowie BE, Purkis JM, Austin J, Love JB, Arnold PL. Thermal and Photochemical Reduction and Functionalization Chemistry of the Uranyl Dication, [UVIO2]2+. Chem Rev 2019; 119:10595-10637. [DOI: 10.1021/acs.chemrev.9b00048] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Bradley E. Cowie
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, The King’s Buildings, Edinburgh EH9 3FJ, U.K
| | - Jamie M. Purkis
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, The King’s Buildings, Edinburgh EH9 3FJ, U.K
| | - Jonathan Austin
- National Nuclear Laboratory, Chadwick House,
Warrington Road, Birchwood Park, Warrington WA3 6AE, U.K
| | - Jason B. Love
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, The King’s Buildings, Edinburgh EH9 3FJ, U.K
| | - Polly L. Arnold
- EaStCHEM School of Chemistry, The University of Edinburgh, Joseph Black Building, The King’s Buildings, Edinburgh EH9 3FJ, U.K
| |
Collapse
|
30
|
Hu SX, Jian J, Li J, Gibson JK. Destruction of the Uranyl Moiety in a U(V) “Cation–Cation” Interaction. Inorg Chem 2019; 58:10148-10159. [DOI: 10.1021/acs.inorgchem.9b01265] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shu-Xian Hu
- Beijing Computational Science Research Center, Beijing 100193, China
- Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Jiwen Jian
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jun Li
- Department of Chemistry and Key Laboratory of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - John K. Gibson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| |
Collapse
|
31
|
Lakaniemi AM, Douglas GB, Kaksonen AH. Engineering and kinetic aspects of bacterial uranium reduction for the remediation of uranium contaminated environments. JOURNAL OF HAZARDOUS MATERIALS 2019; 371:198-212. [PMID: 30851673 DOI: 10.1016/j.jhazmat.2019.02.074] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 01/29/2019] [Accepted: 02/20/2019] [Indexed: 06/09/2023]
Abstract
Biological reduction of soluble uranium from U(VI) to insoluble U(IV) coupled to the oxidation of an electron donor (hydrogen or organic compounds) is a potentially cost-efficient way to reduce the U concentrations in contaminated waters to below regulatory limits. A variety of microorganisms originating from both U contaminated and non-contaminated environments have demonstrated U(VI) reduction capacity under anaerobic conditions. Bioreduction of U(VI) is considered especially promising for in situ remediation, where the activity of indigenous microorganisms is stimulated by supplying a suitable electron donor to the subsurface to contain U contamination to a specific location in a sparingly soluble form. Less studied microbial biofilm-based bioreactors and bioelectrochemical systems have also shown potential for efficient U(VI) reduction to remove U from contaminated water streams. This review compares the advantages and challenges of U(VI)-reducing in situ remediation processes, bioreactors and bioelectrochemical systems. In addition, the current knowledge of U(VI) bioreduction mechanisms and factors affecting U(VI) reduction kinetics (e.g. pH, temperature, and the chemical composition of the contaminated water) are discussed, as both of these aspects are important in designing efficient remediation processes.
Collapse
Affiliation(s)
- Aino-Maija Lakaniemi
- Tampere University, Faculty of Engineering and Natural Sciences, P.O. Box 541, FI- 33104, Tampere University, Finland; CSIRO Land and Water, 147 Underwood Avenue, Floreat, Western Australia, 6014, Australia.
| | - Grant B Douglas
- CSIRO Land and Water, 147 Underwood Avenue, Floreat, Western Australia, 6014, Australia
| | - Anna H Kaksonen
- CSIRO Land and Water, 147 Underwood Avenue, Floreat, Western Australia, 6014, Australia
| |
Collapse
|
32
|
Ferreira MR, Salgueiro CA. Biomolecular Interaction Studies Between Cytochrome PpcA From Geobacter sulfurreducens and the Electron Acceptor Ferric Nitrilotriacetate (Fe-NTA). Front Microbiol 2018; 9:2741. [PMID: 30524391 PMCID: PMC6262392 DOI: 10.3389/fmicb.2018.02741] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 10/26/2018] [Indexed: 11/17/2022] Open
Abstract
Geobacter sulfurreducens bacterium exhibits an enormous respiratory versatility, including the utilization of several toxic and radioactive metals as electron acceptors. This versatility is also replicated in the capability of the most abundant cytochrome in G. sulfurreducens, the periplasmic triheme cytochrome PpcA, to reduce uranium, chromium and other metal ions. From all possible electron transfer pathways in G. sulfurreducens, those involved in the iron reduction are the best characterized to date. Previously, we provided structural evidence for the complex interface established between PpcA and the electron acceptor Fe(III)-citrate. However, genetic studies suggested that this acceptor is mainly reduced by outer membrane cytochomes. In the present work, we used UV-visible measurements to demonstrate that PpcA is able to directly reduce the electron acceptor ferric nitrilotriacetate (Fe-NTA), a more outer membrane permeable iron chelated form. In addition, the molecular interactions between PpcA and Fe-NTA were probed by Nuclear Magnetic Resonance (NMR) spectroscopy. The NMR spectra obtained for PpcA samples in the absence and presence of Fe-NTA showed that the interaction is reversible and encompasses a positively charged surface region located in the vicinity of the heme IV. Overall, the study elucidates the formation of an electron transfer complex between PpcA and a readily outer-membrane permeable iron chelated form. The structural and functional relationships obtained explain how a single cytochrome is designed to effectively interact with a wide range of G. sulfurreducens electron acceptors, a feature that can be explored for optimal bioelectrochemical applications.
Collapse
Affiliation(s)
- Marisa R Ferreira
- UCIBIO-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Carlos A Salgueiro
- UCIBIO-REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| |
Collapse
|
33
|
Lu G, Haes AJ, Forbes TZ. Detection and identification of solids, surfaces, and solutions of uranium using vibrational spectroscopy. Coord Chem Rev 2018; 374:314-344. [PMID: 30713345 PMCID: PMC6358285 DOI: 10.1016/j.ccr.2018.07.010] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The purpose of this review is to provide an overview of uranium speciation using vibrational spectroscopy methods including Raman and IR. Uranium is a naturally occurring, radioactive element that is utilized in the nuclear energy and national security sectors. Fundamental uranium chemistry is also an active area of investigation due to ongoing questions regarding the participation of 5f orbitals in bonding, variation in oxidation states and coordination environments, and unique chemical and physical properties. Importantly, uranium speciation affects fate and transportation in the environment, influences bioavailability and toxicity to human health, controls separation processes for nuclear waste, and impacts isotopic partitioning and geochronological dating. This review article provides a thorough discussion of the vibrational modes for U(IV), U(V), and U(VI) and applications of infrared absorption and Raman scattering spectroscopies in the identification and detection of both naturally occurring and synthetic uranium species in solid and solution states. The vibrational frequencies of the uranyl moiety, including both symmetric and asymmetric stretches are sensitive to the coordinating ligands and used to identify individual species in water, organic solvents, and ionic liquids or on the surface of materials. Additionally, vibrational spectroscopy allows for the in situ detection and real-time monitoring of chemical reactions involving uranium. Finally, techniques to enhance uranium species signals with vibrational modes are discussed to expand the application of vibrational spectroscopy to biological, environmental, inorganic, and materials scientists and engineers.
Collapse
Affiliation(s)
- Grace Lu
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Amanda J. Haes
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| | - Tori Z. Forbes
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, United States
| |
Collapse
|
34
|
Niklas JE, Hardy EE, Gorden AEV. Solid-state structural elucidation and electrochemical analysis of uranyl naphthylsalophen. Chem Commun (Camb) 2018; 54:11693-11696. [PMID: 30177989 DOI: 10.1039/c8cc05242e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A salophen ligand derivative incorporating naphthalene (naphthylsalophen = [H2L]) and the corresponding uranyl (UO22+) complex have been synthesized and characterized both in solution and the solid-state. A hydrogen bonding uranyl tetramer and the electrochemical analysis of [H2L] and UO2[L] are described.
Collapse
Affiliation(s)
- Julie E Niklas
- Auburn University, 179 Chemistry Building, Auburn, AL 36849, USA.
| | | | | |
Collapse
|
35
|
Faizova R, White S, Scopelliti R, Mazzanti M. The effect of iron binding on uranyl(v) stability. Chem Sci 2018; 9:7520-7527. [PMID: 30319752 PMCID: PMC6179087 DOI: 10.1039/c8sc02099j] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/31/2018] [Indexed: 11/21/2022] Open
Abstract
The tripodal heptadentate Schiff base trensal3– ligand allowed the synthesis and characterization of stable uranyl(v) complexes presenting UO2+···K+ or UO2+···Fe2+ cation–cation interactions. The presence of Fe2+ bound to the uranyl(v) oxygen leads to increased stability with respect to proton induced disproportionation and to an increased range of stability of the uranyl(v) species with respect both to oxidation and reduction reactions.
Here we report the effect of UO2+···Fe2+ cation–cation interactions on the redox properties of uranyl(v) complexes and on their stability with respect to proton induced disproportionation. The tripodal heptadentate Schiff base trensal3– ligand allowed the synthesis and characterization of the uranyl(vi) complexes [UO2(trensal)K], 1 and [UO2(Htrensal)], 2 and of uranyl(v) complexes presenting UO2+···K+ or UO2+···Fe2+ cation–cation interactions ([UO2(trensal)K]K, 3, [UO2(trensal)] [K(2.2.2crypt)][K(2.2.2crypt)], 4, [UO2(trensal)Fe(py)3], 6). The uranyl(v) complexes show similar stability in pyridine solution, but the presence of Fe2+ bound to the uranyl(v) oxygen leads to increased stability with respect to proton induced disproportionation through the formation of a stable Fe2+–UO2+–U4+ intermediate ([UO2(trensal)Fe(py)3U(trensal)]I, 7) upon addition of 2 eq. of PyHCl to 6. The addition of 2 eq. of PyHCl to 3 results in the immediate formation of U(iv) and UO22+ compounds. The presence of an additional UO2+ bound Fe2+ in [(UO2(trensal)Fe(py)3)2Fe(py)3]I2, 8, does not lead to increased stability. Redox reactivity and cyclic voltammetry studies also show an increased range of stability of the uranyl(v) species in the presence of Fe2+ with respect both to oxidation and reduction reactions, while the presence of a proton in complex 2 results in a smaller stability range for the uranyl(v) species. Cyclic voltammetry studies also show that the presence of a Fe2+ cation bound through one trensal3– arm in the trinuclear complex [{UO2(trensal)}2Fe], 5 does not lead to increased redox stability of the uranyl(v) showing the important role of UO2+···Fe2+ cation–cation interactions in increasing the stability of uranyl(v). These results provide an important insight into the role that iron binding may play in stabilizing uranyl(v) compounds in the environmental mineral-mediated reduction of uranium(vi).
Collapse
Affiliation(s)
- Radmila Faizova
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland .
| | - Sarah White
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland .
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland .
| | - Marinella Mazzanti
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland .
| |
Collapse
|
36
|
Faizova R, Scopelliti R, Chauvin AS, Mazzanti M. Synthesis and Characterization of a Water Stable Uranyl(V) Complex. J Am Chem Soc 2018; 140:13554-13557. [PMID: 30289696 DOI: 10.1021/jacs.8b07885] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have identified a polydentate aminocarboxylate ligand that stabilizes uranyl(V) in water. The mononuclear [UO2(dpaea)]X, (dpaeaH2 = Bis(pyridyl-6-methyl-2-carboxylate)-ethylamine; X = CoCp2*+ or X = K(2.2.2.cryptand) complexes have been isolated from anaerobic organic solution, crystallographically and spectroscopically characterized both in water and organic solution. These complexes disproportionate at pH ≤ 6, but are stable in anaerobic water at pH 7-10 for several days.
Collapse
Affiliation(s)
- Radmila Faizova
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
| | - Anne-Sophie Chauvin
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
| | - Marinella Mazzanti
- Institut des Sciences et Ingénierie Chimiques , Ecole Polytechnique Fédérale de Lausanne (EPFL) , CH-1015 Lausanne , Switzerland
| |
Collapse
|
37
|
Carugo O. Structural features of uranium-protein complexes. J Inorg Biochem 2018; 189:1-6. [PMID: 30149122 DOI: 10.1016/j.jinorgbio.2018.08.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/19/2018] [Accepted: 08/16/2018] [Indexed: 02/06/2023]
Abstract
Uranium toxicity depends on its chemical properties rather than on its radioactivity and involves its interaction with macromolecules. Here, a systematic survey of the structural features of the uranyl sites observed in protein crystal structures deposited in the Protein Data Bank is reported. Beside the two uranyl oxygens, which occupy the axial positions, uranium tends to be coordinated by five other oxygen atoms, which occupy the equatorial vertices of a pentagonal bipyramid. Even if one or more of these equatorial positions are sometime empty, they can be occupied only by oxygen atoms that belong to the carboxylate groups of Glu and Asp side-chains, usually acting as monodentate ligands, to water molecules, or to acetate anions. Although several uranium sites appear undefined or unrefined, with a single uranium atom that lacks the two uranyl oxygen atoms, this problem seems to become less frequent in recent years. However, it is clear that the crystallographic refinements of the uranyl sites are not always well restrained and a better parametrization of these restraints seems to be necessary.
Collapse
Affiliation(s)
- Oliviero Carugo
- Chemistry Department, University of Pavia, Italy; Department of Structural and Computational Biology, University of Vienna, Austria.
| |
Collapse
|
38
|
Kolhe N, Zinjarde S, Acharya C. Responses exhibited by various microbial groups relevant to uranium exposure. Biotechnol Adv 2018; 36:1828-1846. [PMID: 30017503 DOI: 10.1016/j.biotechadv.2018.07.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 07/08/2018] [Accepted: 07/09/2018] [Indexed: 11/28/2022]
Abstract
There is a strong interest in knowing how various microbial systems respond to the presence of uranium (U), largely in the context of bioremediation. There is no known biological role for uranium so far. Uranium is naturally present in rocks and minerals. The insoluble nature of the U(IV) minerals keeps uranium firmly bound in the earth's crust minimizing its bioavailability. However, anthropogenic nuclear reaction processes over the last few decades have resulted in introduction of uranium into the environment in soluble and toxic forms. Microbes adsorb, accumulate, reduce, oxidize, possibly respire, mineralize and precipitate uranium. This review focuses on the microbial responses to uranium exposure which allows the alteration of the forms and concentrations of uranium within the cell and in the local environment. Detailed information on the three major bioprocesses namely, biosorption, bioprecipitation and bioreduction exhibited by the microbes belonging to various groups and subgroups of bacteria, fungi and algae is provided in this review elucidating their intrinsic and engineered abilities for uranium removal. The survey also highlights the instances of the field trials undertaken for in situ uranium bioremediation. Advances in genomics and proteomics approaches providing the information on the regulatory and physiologically important determinants in the microbes in response to uranium challenge have been catalogued here. Recent developments in metagenomics and metaproteomics indicating the ecologically relevant traits required for the adaptation and survival of environmental microbes residing in uranium contaminated sites are also included. A comprehensive understanding of the microbial responses to uranium can facilitate the development of in situ U bioremediation strategies.
Collapse
Affiliation(s)
- Nilesh Kolhe
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune 411007, India; Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Smita Zinjarde
- Institute of Bioinformatics and Biotechnology, Savitribai Phule Pune University, Pune 411007, India; Department of Microbiology, Savitribai Phule Pune University, Pune 411007, India.
| | - Celin Acharya
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India; Homi Bhabha National Institute, Anushakti Nagar, Trombay, Mumbai 400094, India.
| |
Collapse
|
39
|
Qiu M, Wang M, Zhao Q, Hu B, Zhu Y. XANES and EXAFS investigation of uranium incorporation on nZVI in the presence of phosphate. CHEMOSPHERE 2018; 201:764-771. [PMID: 29550570 DOI: 10.1016/j.chemosphere.2018.03.057] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/07/2018] [Accepted: 03/08/2018] [Indexed: 06/08/2023]
Abstract
Effect of phosphate on the reduction of U(VI) on nZVI was determined by batch, XPS, XANES and EXAFS techniques. The batch experiments showed that nZVI was quite effective for the removal of uranium under the anaerobic conditions, whereas the addition of phosphate enhanced uranium removal over wide pH range. At low pH, the reduction of U(VI) to U(IV) significantly decreased with increasing phosphate concentration by XPS and XANES analysis. According to EXAFS analysis, the occurrence of UU shell at 10 mg/L phosphate and pH 4.0 was similar to that of U(IV)O2(s), whereas the UP and UFe shells were observed at 50 mg/L phosphate, revealing that reductive co-precipitate (U(IV)O2(s)) and precipitation of uranyl-phosphate were observed at low and high phosphate, respectively. The findings are crucial for the prediction of the effect of phosphate on the speciation and binding of uranium by nZVI at low pH, which is significant in controlling the mobility of U(VI) in contaminated environments.
Collapse
Affiliation(s)
- Muqing Qiu
- School of Life Science, Shaoxing University, Huancheng West Road 508, Shaoxing 312000, PR China
| | - Min Wang
- State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi'an University of Technology, Jing Hua Road 5, Xi'an 710048, PR China
| | - Qingzhou Zhao
- College of Resources and Environment, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing 100049, PR China
| | - Baowei Hu
- School of Life Science, Shaoxing University, Huancheng West Road 508, Shaoxing 312000, PR China.
| | - Yuling Zhu
- School of Life Science, Shaoxing University, Huancheng West Road 508, Shaoxing 312000, PR China
| |
Collapse
|
40
|
Vats BG, Das D, Sadhu B, Kannan S, Pius IC, Noronha DM, Sundararajan M, Kumar M. Selective recognition of uranyl ions from bulk of thorium(iv) and lanthanide(iii) ions by tetraalkyl urea: a combined experimental and quantum chemical study. Dalton Trans 2018; 45:10319-25. [PMID: 27241102 DOI: 10.1039/c6dt01191h] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The selective separation of uranyl ions from an aqueous solution is one of the most important criteria for sustainable nuclear energy production. We report herein a known, but unexplored extractant, tetraalkyl urea, which shows supreme selectivity for uranium in the presence of interfering thorium and other lanthanide ions from a nitric acid medium. The structural characterization of the uranyl complex (UO2X2·2L, where X = NO3(-), Cl(-) and Br(-)) by IR, NMR and single crystal X-ray diffraction provides insight into the strong interaction between the uranyl ion and the ligand. The origin of this supreme selectivity for uranyl ions is further supported by electronic structure calculations. Uranyl binding with the extractant is thermodynamically more favourable when compared to thorium and the selectivity is achieved through a combination of electronic and steric effects.
Collapse
Affiliation(s)
- Bal Govind Vats
- Fuel Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
| | - Debasish Das
- Fuel Reprocessing Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Biswajit Sadhu
- Radiation Safety Systems Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - S Kannan
- Fuel Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
| | - I C Pius
- Fuel Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
| | - D M Noronha
- Fuel Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
| | - Mahesh Sundararajan
- Theoretical Chemistry Section, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
| | - Mukesh Kumar
- Solid state physics division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| |
Collapse
|
41
|
Bell NL, Arnold PL, Love JB. Controlling uranyl oxo group interactions to group 14 elements using polypyrrolic Schiff-base macrocyclic ligands. Dalton Trans 2018; 45:15902-15909. [PMID: 27356021 DOI: 10.1039/c6dt01948j] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Heterodinuclear uranyl/group 14 complexes of the aryl- and anthracenyl-linked Schiff-base macrocyclic ligands LMe and LA were synthesised by reaction of UO2(H2L) with M{N(SiMe3)2}2 (M = Ge, Sn, Pb). For complexes of the anthracenyl-linked ligand (LA) the group 14 metal sits out of the N4-donor plane by up to 0.7 Å resulting in relatively short MOUO distances which decrease down the group; however, the solid state structures and IR spectroscopic analyses suggest little interaction occurs between the oxo and group 14 metal. In contrast, the smaller aryl-linked ligand (LMe) enforces greater interaction between the metals; only the PbII complex was cleanly accessible although this complex was relatively unstable in the presence of HN(SiMe3)2 and some organic oxidants. In this case, the equatorial coordination of pyridine-N-oxide causes a 0.08 Å elongation of the endo UO bond and a clear interaction of the uranyl ion with the Pb(ii) cation in the second donor compartment.
Collapse
Affiliation(s)
- Nicola L Bell
- EaStCHEM School of chemistry, Joseph Black Building, The King's Buildings, The University of Edinburgh, West Mains Road, Edinburgh EH9 3FJ, UK.
| | - Polly L Arnold
- EaStCHEM School of chemistry, Joseph Black Building, The King's Buildings, The University of Edinburgh, West Mains Road, Edinburgh EH9 3FJ, UK.
| | - Jason B Love
- EaStCHEM School of chemistry, Joseph Black Building, The King's Buildings, The University of Edinburgh, West Mains Road, Edinburgh EH9 3FJ, UK.
| |
Collapse
|
42
|
Solution structure and dynamics of the outer membrane cytochrome OmcF from Geobacter sulfurreducens. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:733-741. [DOI: 10.1016/j.bbabio.2017.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/24/2017] [Accepted: 03/31/2017] [Indexed: 11/15/2022]
|
43
|
Collins RN, Rosso KM. Mechanisms and Rates of U(VI) Reduction by Fe(II) in Homogeneous Aqueous Solution and the Role of U(V) Disproportionation. J Phys Chem A 2017; 121:6603-6613. [PMID: 28809500 DOI: 10.1021/acs.jpca.7b05965] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Molecular-level pathways in the aqueous redox transformation of uranium by iron remain unclear, despite the importance of this knowledge for predicting uranium transport and distribution in natural and engineered environments. As the relative importance of homogeneous versus heterogeneous pathways is difficult to probe experimentally, here we apply computational molecular simulation to isolate rates of key one electron transfer reactions in the homogeneous pathway. By comparison to experimental observations the role of the heterogeneous pathway also becomes clear. Density functional theory (DFT) and Marcus theory calculations for all primary monomeric species at pH values ≤7 show for UO22+ and its hydrolysis species UO2OH+ and UO2(OH)20 that reduction by Fe2+ is thermodynamically favorable, though kinetically limited for UO22+. An inner-sphere encounter complex between UO2OH+ and Fe2+ was the most stable for the first hydrolysis species and displayed an electron transfer rate constant ket = 4.3 × 103 s-1. Three stable inner- and outer-sphere encounter complexes between UO2(OH)20 and Fe2+ were found, with electron transfer rate constants ranging from ket = 7.6 × 102 to 7.2 × 104 s-1. Homogeneous reduction of these U(VI) hydrolysis species to U(V) is, therefore, predicted to be facile. In contrast, homogeneous reduction of UO2+ by Fe2+ was found to be thermodynamically unfavorable, suggesting the possible importance of U(V)-U(V) disproportionation as a route to U(IV). Calculations on homogeneous disproportionation, however, while yielding a stable outer-sphere U(V)-U(V) encounter complex, indicate that this electron transfer reaction is not feasible at circumneutral pH. Protonation of both axial O atoms of acceptor U(V) (i.e., by H3O+) was found to be a prerequisite to stabilize U(IV), consistent with the experimental observation that the rate of this reaction is inversely correlated with pH. Thus, despite prevailing notions that U(V) is rapidly eliminated by homogeneous disproportionation, this pathway is irrelevant at environmental conditions.
Collapse
Affiliation(s)
- Richard N Collins
- UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia , Sydney, NSW, Australia 2052
| | - Kevin M Rosso
- UNSW Water Research Centre, School of Civil and Environmental Engineering, UNSW Australia , Sydney, NSW, Australia 2052.,Physical Sciences Division, Pacific Northwest National Laboratory , Richland, Washington 99336, United States
| |
Collapse
|
44
|
Niklas JE, Farnum BH, Gorden JD, Gorden AEV. Structural Characterization and Redox Activity of a Uranyl Dimer and Transition-Metal Complexes of a Tetradentate BIAN Ligand. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00454] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julie E. Niklas
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Byron H. Farnum
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - John D. Gorden
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Anne E. V. Gorden
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| |
Collapse
|
45
|
Response of Microbial Community Function to Fluctuating Geochemical Conditions within a Legacy Radioactive Waste Trench Environment. Appl Environ Microbiol 2017; 83:AEM.00729-17. [PMID: 28667104 PMCID: PMC5561297 DOI: 10.1128/aem.00729-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 06/20/2017] [Indexed: 02/06/2023] Open
Abstract
During the 1960s, small quantities of radioactive materials were codisposed with chemical waste at the Little Forest Legacy Site (Sydney, Australia) in 3-meter-deep, unlined trenches. Chemical and microbial analyses, including functional and taxonomic information derived from shotgun metagenomics, were collected across a 6-week period immediately after a prolonged rainfall event to assess the impact of changing water levels upon the microbial ecology and contaminant mobility. Collectively, results demonstrated that oxygen-laden rainwater rapidly altered the redox balance in the trench water, strongly impacting microbial functioning as well as the radiochemistry. Two contaminants of concern, plutonium and americium, were shown to transition from solid-iron-associated species immediately after the initial rainwater pulse to progressively more soluble moieties as reducing conditions were enhanced. Functional metagenomics revealed the potentially important role that the taxonomically diverse microbial community played in this transition. In particular, aerobes dominated in the first day, followed by an increase of facultative anaerobes/denitrifiers at day 4. Toward the mid-end of the sampling period, the functional and taxonomic profiles depicted an anaerobic community distinguished by a higher representation of dissimilatory sulfate reduction and methanogenesis pathways. Our results have important implications to similar near-surface environmental systems in which redox cycling occurs. IMPORTANCE The role of chemical and microbiological factors in mediating the biogeochemistry of groundwaters from trenches used to dispose of radioactive materials during the 1960s is examined in this study. Specifically, chemical and microbial analyses, including functional and taxonomic information derived from shotgun metagenomics, were collected across a 6-week period immediately after a prolonged rainfall event to assess how changing water levels influence microbial ecology and contaminant mobility. Results demonstrate that oxygen-laden rainwater rapidly altered the redox balance in the trench water, strongly impacting microbial functioning as well as the radiochemistry. Two contaminants of concern, plutonium and americium, were shown to transition from solid-iron-associated species immediately after the initial rainwater pulse to progressively more soluble moieties as reducing conditions were enhanced. Functional metagenomics revealed the important role that the taxonomically diverse microbial community played in this transition. Our results have important implications to similar near-surface environmental systems in which redox cycling occurs.
Collapse
|
46
|
A Highly Expressed High-Molecular-Weight S-Layer Complex of Pelosinus sp. Strain UFO1 Binds Uranium. Appl Environ Microbiol 2017; 83:AEM.03044-16. [PMID: 27913415 DOI: 10.1128/aem.03044-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 11/20/2016] [Indexed: 12/13/2022] Open
Abstract
Cell suspensions of Pelosinus sp. strain UFO1 were previously shown, using spectroscopic analysis, to sequester uranium as U(IV) complexed with carboxyl and phosphoryl group ligands on proteins. The goal of our present study was to characterize the proteins involved in uranium binding. Virtually all of the uranium in UFO1 cells was associated with a heterodimeric protein, which was termed the uranium-binding complex (UBC). The UBC was composed of two S-layer domain proteins encoded by UFO1_4202 and UFO1_4203. Samples of UBC purified from the membrane fraction contained 3.3 U atoms/heterodimer, but significant amounts of phosphate were not detected. The UBC had an estimated molecular mass by gel filtration chromatography of 15 MDa, and it was proposed to contain 150 heterodimers (UFO1_4203 and UFO1_4202) and about 500 uranium atoms. The UBC was also the dominant extracellular protein, but when purified from the growth medium, it contained only 0.3 U atoms/heterodimer. The two genes encoding the UBC were among the most highly expressed genes within the UFO1 genome, and their expressions were unchanged by the presence or absence of uranium. Therefore, the UBC appears to be constitutively expressed and is the first line of defense against uranium, including by secretion into the extracellular medium. Although S-layer proteins were previously shown to bind U(VI), here we showed that U(IV) binds to S-layer proteins, we identified the proteins involved, and we quantitated the amount of uranium bound. IMPORTANCE Widespread uranium contamination from industrial sources poses hazards to human health and to the environment. Herein, we identified a highly abundant uranium-binding complex (UBC) from Pelosinus sp. strain UFO1. The complex makes up the primary protein component of the S-layer of strain UFO1 and binds 3.3 atoms of U(IV) per heterodimer. While other bacteria have been shown to bind U(VI) on their S-layer, we demonstrate here an example of U(IV) bound by an S-layer complex. The UBC provides a potential tool for the microbiological sequestration of uranium for the cleaning of contaminated environments.
Collapse
|
47
|
Wufuer R, Wei Y, Lin Q, Wang H, Song W, Liu W, Zhang D, Pan X, Gadd GM. Uranium Bioreduction and Biomineralization. ADVANCES IN APPLIED MICROBIOLOGY 2017; 101:137-168. [PMID: 29050665 DOI: 10.1016/bs.aambs.2017.01.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Following the development of nuclear science and technology, uranium contamination has been an ever increasing concern worldwide because of its potential for migration from the waste repositories and long-term contaminated environments. Physical and chemical techniques for uranium pollution are expensive and challenging. An alternative to these technologies is microbially mediated uranium bioremediation in contaminated water and soil environments due to its reduced cost and environmental friendliness. To date, four basic mechanisms of uranium bioremediation-uranium bioreduction, biosorption, biomineralization, and bioaccumulation-have been established, of which uranium bioreduction and biomineralization have been studied extensively. The objective of this review is to provide an understanding of recent developments in these two fields in relation to relevant microorganisms, mechanisms, influential factors, and obstacles.
Collapse
|
48
|
Majumder ELW, Wall JD. Uranium Bio-Transformations: Chemical or Biological Processes? ACTA ACUST UNITED AC 2017. [DOI: 10.4236/ojic.2017.72003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
49
|
Kannan S, Kumar M, Sadhu B, Jaccob M, Sundararajan M. Unusual intramolecular CH⋯O hydrogen bonding interaction between a sterically bulky amide and uranyl oxygen. Dalton Trans 2017; 46:16939-16946. [DOI: 10.1039/c7dt02760e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An unusual intramolecular CH⋯O hydrogen bonding interaction between a sterically bulky amide and uranyl oxygen is found to selectively extract uranyl.
Collapse
Affiliation(s)
| | - Mukesh Kumar
- Solid State Physics Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| | - Biswajit Sadhu
- Radiation Safety and Systems Division
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| | | | - Mahesh Sundararajan
- Theoretical Chemistry Section
- Bhabha Atomic Research Centre
- Mumbai-400085
- India
| |
Collapse
|
50
|
Cherkouk A, Law GTW, Rizoulis A, Law K, Renshaw JC, Morris K, Livens FR, Lloyd JR. Influence of riboflavin on the reduction of radionuclides by Shewanella oneidenis MR-1. Dalton Trans 2016; 45:5030-7. [PMID: 26632613 DOI: 10.1039/c4dt02929a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Uranium (as UO2(2+)), technetium (as TcO4(-)) and neptunium (as NpO2(+)) are highly mobile radionuclides that can be reduced enzymatically by a range of anaerobic and facultatively anaerobic microorganisms, including Shewanella oneidensis MR-1, to poorly soluble species. The redox chemistry of Pu is more complicated, but the dominant oxidation state in most environments is highly insoluble Pu(IV), which can be reduced to Pu(III) which has a potentially increased solubility which could enhance migration of Pu in the environment. Recently it was shown that flavins (riboflavin and flavin mononucleotide (FMN)) secreted by Shewanella oneidensis MR-1 can act as electron shuttles, promoting anoxic growth coupled to the accelerated reduction of poorly-crystalline Fe(III) oxides. Here, we studied the role of riboflavin in mediating the reduction of radionuclides in cultures of Shewanella oneidensis MR-1. Our results demonstrate that the addition of 10 μM riboflavin enhances the reduction rate of Tc(VII) to Tc(IV), Pu(IV) to Pu(III) and to a lesser extent, Np(V) to Np(IV), but has no significant influence on the reduction rate of U(VI) by Shewanella oneidensis MR-1. Thus riboflavin can act as an extracellular electron shuttle to enhance rates of Tc(VII), Np(V) and Pu(IV) reduction, and may therefore play a role in controlling the oxidation state of key redox active actinides and fission products in natural and engineered environments. These results also suggest that the addition of riboflavin could be used to accelerate the bioremediation of radionuclide-contaminated environments.
Collapse
Affiliation(s)
- Andrea Cherkouk
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
| | - Gareth T W Law
- Centre for Radiochemistry Research, School of Chemistry, Manchester, M13 9PL, UK
| | - Athanasios Rizoulis
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
| | - Katie Law
- Centre for Radiochemistry Research, School of Chemistry, Manchester, M13 9PL, UK
| | - Joanna C Renshaw
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
| | - Katherine Morris
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
| | - Francis R Livens
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK. and Centre for Radiochemistry Research, School of Chemistry, Manchester, M13 9PL, UK
| | - Jonathan R Lloyd
- Research Centre for Radwaste Disposal and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester M13 9PL, UK.
| |
Collapse
|