Uranium isotope fractionation by abiotic reductive precipitation

Brown, Shaun T.; Basu, Anirban; Ding, Xin; Christensen, John N.; DePaolo, Donald J.

doi:10.1073/pnas.1805234115

Title: Uranium isotope fractionation by abiotic reductive precipitation

Abstract

Significant uranium (U) isotope fractionation has been observed during abiotic reduction of aqueous U, counter to the expectation that uranium isotopes are only fractionated by bioassociated enzymatic reduction. In our experiments, aqueous U is removed from solution by reductive precipitation onto the surfaces of synthetic iron monosulfide. The magnitude of uranium isotopic fractionation increases with decreasing aqueous U removal rate and with increasing amounts of neutrally charged aqueous Ca-U-CO₃ species. Here, our discovery means that abiotic U isotope fractionation likely occurs in any reducing environment with aqueous Ca ≥ 1 mM, and that the magnitude of isotopic fractionation changes in response to changes in aqueous major ion concentrations that affect U speciation. Our results have implications for the study of anoxia in the ancient oceans and other environments.

Authors:

; Basu, Anirban; Ding, Xin; Christensen, John N.; DePaolo, Donald J.

Publication Date:: Thu Aug 16 00:00:00 EDT 2018

Research Org.:: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:: USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:: 1464871

Alternate Identifier(s):: OSTI ID: 1476603

Grant/Contract Number:: AC02-05CH11231

Resource Type:: Published Article

Journal Name:: Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:: Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 115 Journal Issue: 35; Journal ID: ISSN 0027-8424

Publisher:: National Academy of Sciences, Washington, DC (United States)

Country of Publication:: United States

Language:: English

Subject:: 07 ISOTOPE AND RADIATION SOURCES; uranium; abiotic fractionation; isotopes; isotope fractionation

Citation Formats


                    Brown, Shaun T., Basu, Anirban, Ding, Xin, Christensen, John N., and DePaolo, Donald J. Uranium isotope fractionation by abiotic reductive precipitation.  United States: N. p., 2018. 
Web.  doi:10.1073/pnas.1805234115.

Copy to clipboard


                    Brown, Shaun T., Basu, Anirban, Ding, Xin, Christensen, John N., & DePaolo, Donald J. Uranium isotope fractionation by abiotic reductive precipitation.  United States.  https://doi.org/10.1073/pnas.1805234115

Copy to clipboard


                    Brown, Shaun T., Basu, Anirban, Ding, Xin, Christensen, John N., and DePaolo, Donald J. Thu .  
"Uranium isotope fractionation by abiotic reductive precipitation".  United States.  https://doi.org/10.1073/pnas.1805234115.

Copy to clipboard


                    
@article{osti_1464871,

  title        = {Uranium isotope fractionation by abiotic reductive precipitation},

  author       = {Brown, Shaun T. and Basu, Anirban and Ding, Xin and Christensen, John N. and DePaolo, Donald J.},

  abstractNote = {Significant uranium (U) isotope fractionation has been observed during abiotic reduction of aqueous U, counter to the expectation that uranium isotopes are only fractionated by bioassociated enzymatic reduction. In our experiments, aqueous U is removed from solution by reductive precipitation onto the surfaces of synthetic iron monosulfide. The magnitude of uranium isotopic fractionation increases with decreasing aqueous U removal rate and with increasing amounts of neutrally charged aqueous Ca-U-CO3 species. Here, our discovery means that abiotic U isotope fractionation likely occurs in any reducing environment with aqueous Ca ≥ 1 mM, and that the magnitude of isotopic fractionation changes in response to changes in aqueous major ion concentrations that affect U speciation. Our results have implications for the study of anoxia in the ancient oceans and other environments.},

  doi          = {10.1073/pnas.1805234115},

  journal      = {Proceedings of the National Academy of Sciences of the United States of America},

  number       = 35,

  volume       = 115,

  place        = {United States},

  year         = {Thu Aug 16 00:00:00 EDT 2018},

  month        = {Thu Aug 16 00:00:00 EDT 2018}

}

Copy to clipboard

Journal Article:

Free Publicly Available Full Text

Publisher's Version of Record
https://doi.org/10.1073/pnas.1805234115

Other availability

Search WorldCat to find libraries that may hold this journal

Citation Metrics:

Cited by: 56 works

Citation information provided by
Web of Science

Save / Share:

Export Metadata

Save to My Library

Works referenced in this record:

Influence of Dynamical Conditions on the Reduction of U ^VI at the Magnetite−Solution Interface
journal, January 2010

Ilton, Eugene S.; Boily, Jean-François; Buck, Edgar C.
Environmental Science & Technology, Vol. 44, Issue 1
DOI: 10.1021/es9014597

Isotopic Tracking of Hanford 300 Area Derived Uranium in the Columbia River
journal, December 2010

Christensen, John N.; Dresel, P. Evan; Conrad, Mark E.
Environmental Science & Technology, Vol. 44, Issue 23
DOI: 10.1021/es1025799

Uranium reduction on magnetite: Probing for pentavalent uranium using electrochemical methods
journal, May 2015

Yuan, Ke; Renock, Devon; Ewing, Rodney C.
Geochimica et Cosmochimica Acta, Vol. 156
DOI: 10.1016/j.gca.2015.02.014

Exchange Reactions of Uranium Ions in Solution
journal, October 1950

Rona, Elizabeth
Journal of the American Chemical Society, Vol. 72, Issue 10
DOI: 10.1021/ja01166a001

Isotope fractionation of 238U and 235U during biologically-mediated uranium reduction
journal, August 2015

Stirling, Claudine H.; Andersen, Morten B.; Warthmann, Rolf
Geochimica et Cosmochimica Acta, Vol. 163
DOI: 10.1016/j.gca.2015.03.017

Low-temperature isotopic fractionation of uranium
journal, December 2007

Stirling, Claudine H.; Andersen, Morten B.; Potter, Emma-Kate
Earth and Planetary Science Letters, Vol. 264, Issue 1-2
DOI: 10.1016/j.epsl.2007.09.019

Mass Dependence of Uranium Isotope Effects in the U(IV)−U(VI) Exchange Reaction
journal, January 1996

Nomura, Masao; Higuchi, Nobuhiko; Fujii, Yasuhiko
Journal of the American Chemical Society, Vol. 118, Issue 38
DOI: 10.1021/ja954075s

The thermodynamic properties of isotopic substances
journal, January 1947

Urey, Harold C.
Journal of the Chemical Society (Resumed)
DOI: 10.1039/jr9470000562

Experimentally Determined Uranium Isotope Fractionation During Reduction of Hexavalent U by Bacteria and Zero Valent Iron
journal, November 2006

Rademacher, Laura K.; Lundstrom, Craig C.; Johnson, Thomas M.
Environmental Science & Technology, Vol. 40, Issue 22
DOI: 10.1021/es0604360

U(VI) Sorption and Reduction Kinetics on the Magnetite (111) Surface
journal, March 2012

Singer, David M.; Chatman, Shawn M.; Ilton, Eugene S.
Environmental Science & Technology, Vol. 46, Issue 7
DOI: 10.1021/es203878c

Calculation of Equilibrium Constants for Isotopic Exchange Reactions
journal, May 1947

Bigeleisen, Jacob; Mayer, Maria Goeppert
The Journal of Chemical Physics, Vol. 15, Issue 5
DOI: 10.1063/1.1746492

Uranyl(VI) carbonate complex formation: Validation of the Ca2UO2(CO3)3(aq.) species
journal, January 2001

Bernhard, G.; Geipel, Gerhard; Reich, T.
Radiochimica Acta, Vol. 89, Issue 8
DOI: 10.1524/ract.2001.89.8.511

Reductive Immobilization of Uranium(VI) by Amorphous Iron Sulfide
journal, December 2008

Hua, Bin; Deng, Baolin
Environmental Science & Technology, Vol. 42, Issue 23
DOI: 10.1021/es801225z

Effects of Solution Composition and pH on the Reductive Dechlorination of Hexachloroethane by Iron Sulfide
journal, May 1998

Butler, Elizabeth C.; Hayes, Kim F.
Environmental Science & Technology, Vol. 32, Issue 9
DOI: 10.1021/es9706864

Isotopic Evidence for Reductive Immobilization of Uranium Across a Roll-Front Mineral Deposit
journal, June 2016

Brown, Shaun T.; Basu, Anirban; Christensen, John N.
Environmental Science & Technology, Vol. 50, Issue 12
DOI: 10.1021/acs.est.6b00626

Uranium(VI) Reduction by Iron(II) Monosulfide Mackinawite
journal, February 2012

Hyun, Sung Pil; Davis, James A.; Sun, Kai
Environmental Science & Technology, Vol. 46, Issue 6
DOI: 10.1021/es203786p

Molybdenum Isotope Evidence for Widespread Anoxia in Mid-Proterozoic Oceans
journal, April 2004

Arnold, G. L.
Science, Vol. 304, Issue 5667
DOI: 10.1126/science.1091785

Uranium isotope fractionation induced by aqueous speciation: Implications for U isotopes in marine CaCO 3 as a paleoredox proxy
journal, October 2017

Chen, Xinming; Romaniello, Stephen J.; Anbar, Ariel D.
Geochimica et Cosmochimica Acta, Vol. 215
DOI: 10.1016/j.gca.2017.08.006

Competition between enzymatic and abiotic reduction of uranium(VI) under iron reducing conditions
journal, August 2005

Behrends, Thilo; Van Cappellen, Philippe
Chemical Geology, Vol. 220, Issue 3-4
DOI: 10.1016/j.chemgeo.2005.04.007

Origin of uranium isotope variations in early solar nebula condensates
journal, March 2016

Tissot, François L. H.; Dauphas, Nicolas; Grossman, Lawrence
Science Advances, Vol. 2, Issue 3
DOI: 10.1126/sciadv.1501400

Surface chemistry of disordered mackinawite (FeS)
journal, July 2005

Wolthers, Mariëtte; Charlet, Laurent; van Der Linde, Peter R.
Geochimica et Cosmochimica Acta, Vol. 69, Issue 14
DOI: 10.1016/j.gca.2005.01.027

Abiotic Reductive Immobilization of U(VI) by Biogenic Mackinawite
journal, February 2013

Veeramani, Harish; Scheinost, Andreas C.; Monsegue, Niven
Environmental Science & Technology, Vol. 47, Issue 5
DOI: 10.1021/es304025x

Uranium Isotope Fractionation
journal, January 2017

Andersen, Morten B.; Stirling, Claudine H.; Weyer, Stefan
Reviews in Mineralogy and Geochemistry, Vol. 82, Issue 1
DOI: 10.2138/rmg.2017.82.19

FeS-coated sand for removal of arsenic(III) under anaerobic conditions in permeable reactive barriers
journal, January 2011

Han, Young-Soo; Gallegos, Tanya J.; Demond, Avery H.
Water Research, Vol. 45, Issue 2
DOI: 10.1016/j.watres.2010.09.033

Earth’s oxygen cycle and the evolution of animal life
journal, July 2016

Reinhard, Christopher T.; Planavsky, Noah J.; Olson, Stephanie L.
Proceedings of the National Academy of Sciences, Vol. 113, Issue 32
DOI: 10.1073/pnas.1521544113

Environmental Speciation of Actinides
journal, June 2012

Maher, Kate; Bargar, John R.; Brown, Gordon E.
Inorganic Chemistry, Vol. 52, Issue 7
DOI: 10.1021/ic301686d

Natural fractionation of 238U/235U
journal, January 2008

Weyer, S.; Anbar, A. D.; Gerdes, A.
Geochimica et Cosmochimica Acta, Vol. 72, Issue 2
DOI: 10.1016/j.gca.2007.11.012

Chemical Speciation of Uranium(VI) in Marine Environments: Complexation of Calcium and Magnesium Ions with [(UO ₂ )(CO ₃ ) ₃ ] ⁴⁻ and the Effect on the Extraction of Uranium from Seawater
journal, September 2014

Endrizzi, Francesco; Rao, Linfeng
Chemistry - A European Journal, Vol. 20, Issue 44
DOI: 10.1002/chem.201403262

Optimal methods for estimating kinetic isotope effects from different forms of the Rayleigh distillation equation
journal, February 2004

Scott, K. M.; Lu, X.; Cavanaugh, C. M.
Geochimica et Cosmochimica Acta, Vol. 68, Issue 3
DOI: 10.1016/S0016-7037(03)00459-9

Determination of the Formation Constants of Ternary Complexes of Uranyl and Carbonate with Alkaline Earth Metals (Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , and Ba ²⁺ ) Using Anion Exchange Method
journal, August 2006

Dong, Wenming; Brooks, Scott C.
Environmental Science & Technology, Vol. 40, Issue 15
DOI: 10.1021/es0606327

Fractionation of 238U/235U by reduction during low temperature uranium mineralisation processes
journal, February 2014

Murphy, Melissa J.; Stirling, Claudine H.; Kaltenbach, Angela
Earth and Planetary Science Letters, Vol. 388
DOI: 10.1016/j.epsl.2013.11.034

Inhibition of Bacterial U(VI) Reduction by Calcium
journal, May 2003

Brooks, Scott C.; Fredrickson, James K.; Carroll, Sue L.
Environmental Science & Technology, Vol. 37, Issue 9
DOI: 10.1021/es0210042

Uranium isotopic fractionation factors during U(VI) reduction by bacterial isolates
journal, July 2014

Basu, Anirban; Sanford, Robert A.; Johnson, Thomas M.
Geochimica et Cosmochimica Acta, Vol. 136
DOI: 10.1016/j.gca.2014.02.041

Surface kinetic model for isotopic and trace element fractionation during precipitation of calcite from aqueous solutions
journal, February 2011

DePaolo, Donald J.
Geochimica et Cosmochimica Acta, Vol. 75, Issue 4
DOI: 10.1016/j.gca.2010.11.020

Speciation-Dependent Kinetics of Uranium(VI) Bioreduction
journal, June 2011

Ulrich, Kai-Uwe; Veeramani, Harish; Bernier-Latmani, Rizlan
Geomicrobiology Journal, Vol. 28, Issue 5-6
DOI: 10.1080/01490451.2010.507640

Uranium isotopes fingerprint biotic reduction
journal, April 2015

Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng
Proceedings of the National Academy of Sciences, Vol. 112, Issue 18
DOI: 10.1073/pnas.1421841112

Surface catalysis of uranium(VI) reduction by iron(II)
journal, October 1999

Liger, Emmanuelle; Charlet, Laurent; Van Cappellen, Philippe
Geochimica et Cosmochimica Acta, Vol. 63, Issue 19-20
DOI: 10.1016/S0016-7037(99)00265-3

Formation of ternary CaUO2(CO3)32− and Ca2UO2(CO3)3(aq) complexes under neutral to weakly alkaline conditions
journal, January 2013

Lee, Jun-Yeop; Yun, Jong-Il
Dalton Transactions, Vol. 42, Issue 27
DOI: 10.1039/c3dt50863c

The effect of calcium on aqueous uranium(VI) speciation and adsorption to ferrihydrite and quartz
journal, March 2006

Fox, Patricia M.; Davis, James A.; Zachara, John M.
Geochimica et Cosmochimica Acta, Vol. 70, Issue 6
DOI: 10.1016/j.gca.2005.11.027

Distinct 238 U/ 235 U ratios and REE patterns in plutonic and volcanic angrites: Geochronologic implications and evidence for U isotope fractionation during magmatic processes
journal, September 2017

Tissot, François L. H.; Dauphas, Nicolas; Grove, Timothy L.
Geochimica et Cosmochimica Acta, Vol. 213
DOI: 10.1016/j.gca.2017.06.045

The solubility of FeS
journal, December 2006

Rickard, David
Geochimica et Cosmochimica Acta, Vol. 70, Issue 23
DOI: 10.1016/j.gca.2006.02.029

Isotope fractionation during oxidation of tetravalent uranium by dissolved oxygen
journal, February 2015

Wang, Xiangli; Johnson, Thomas M.; Lundstrom, Craig C.
Geochimica et Cosmochimica Acta, Vol. 150
DOI: 10.1016/j.gca.2014.12.007

Quantifying Constraints Imposed by Calcium and Iron on Bacterial Reduction of Uranium(VI)
journal, January 2007

Stewart, Brandy D.; Neiss, Jim; Fendorf, Scott
Journal of Environment Quality, Vol. 36, Issue 2
DOI: 10.2134/jeq2006.0058

238U/235U Systematics in Terrestrial Uranium-Bearing Minerals
journal, March 2012

Hiess, J.; Condon, D. J.; McLean, N.
Science, Vol. 335, Issue 6076
DOI: 10.1126/science.1215507

Ion desolvation as a mechanism for kinetic isotope fractionation in aqueous systems
journal, October 2012

Hofmann, A. E.; Bourg, I. C.; DePaolo, D. J.
Proceedings of the National Academy of Sciences, Vol. 109, Issue 46
DOI: 10.1073/pnas.1208184109

Uranium stable isotope fractionation in the Black Sea: Modern calibration of the 238U/235U paleo-redox proxy
journal, April 2017

Rolison, John M.; Stirling, Claudine H.; Middag, Rob
Geochimica et Cosmochimica Acta, Vol. 203
DOI: 10.1016/j.gca.2016.12.014

Isotopic and Geochemical Tracers for U(VI) Reduction and U Mobility at an in Situ Recovery U Mine
journal, May 2015

Basu, Anirban; Brown, Shaun T.; Christensen, John N.
Environmental Science & Technology, Vol. 49, Issue 10
DOI: 10.1021/acs.est.5b00701

Uranium isotope fractionation during coprecipitation with aragonite and calcite
journal, September 2016

Chen, Xinming; Romaniello, Stephen J.; Herrmann, Achim D.
Geochimica et Cosmochimica Acta, Vol. 188
DOI: 10.1016/j.gca.2016.05.022

Nuclear Size and Shape Effects in Chemical Reactions. Isotope Chemistry of the Heavy Elements
journal, January 1996

Bigeleisen, Jacob
Journal of the American Chemical Society, Vol. 118, Issue 15
DOI: 10.1021/ja954076k

Similar Records in DOE PAGES and OSTI.GOV collections:

Microbial U Isotope Fractionation Depends on the U(VI) Reduction Rate

Journal Article Basu, Anirban ; Wanner, Christoph ; Johnson, Thomas M. ; ... - Environmental Science and Technology

U isotope fractionation may serve as an accurate proxy for U(VI) reduction in both modern and ancient environments, if the systematic controls on the magnitude of fractionation (epsilon) are known. We model the effect of U(VI) reduction kinetics on U isotopic fractionation during U(VI) reduction by a novel Shewanella isolate, Shewanella sp. (NR), in batch incubations. The measured epsilon values range from 0.96 +/- 0.16 to 0.36 +/- 0.07 parts per thousand and are strongly dependent on the U(VI) reduction rate. The e decreases with increasing reduction rate constants normalized by cell density and initial U(VI). Reactive transport simulations suggestmore »« less
Cited by 14
https://doi.org/10.1021/acs.est.9b05935

Full Text Available
Surface catalysis of uranium(VI) reduction by iron(II)

Journal Article Liger, E ; Charlet, L ; Van Cappellen, P - Geochimica et Cosmochimica Acta

Colloidal hematite ({alpha}-Fe{sub 2}O{sub 3}) is used as model solid to investigate the kinetic effect of specific adsorption interactions on the chemical reduction of uranyl (U{sup VI}O{sub 2}{sup 2+}) by ferrous iron. Acid-base titrations and Fe(II) and uranyl adsorption experiments are performed on hematite suspensions, under O{sub 2}- and CO{sub 2}-free conditions. The results are explained in terms of a constant capacitance surface complexation model of the hematite-aqueous solution interface. Two distinct Fe(II) surface complexes are required to reproduce the data: ({equivalent{underscore}to}Fe{sup III}OFe{sup II}){sup +} (or {equivalent{underscore}to}Fe{sup III}OFe{sup II}(OH{sub 2}){sub n}{sup +}) and {equivalent{underscore}to}Fe{sup III}OFe{sup II}OH{sup 0} (or {equivalent{underscore}to}Fe{sup III}OFe{supmore »« less
https://doi.org/10.1016/S0016-7037(99)00265-3
Speciation-Dependent Microbial Reduction of Uranium Within Iron-Coated Sands

Journal Article Neiss, J ; Stewart, B D ; Nico, P S ; ... - Environ. Sci. Tech. 41:7343,2007

Transport of uranium within surface and subsurface environments is predicated largely on its redox state. Uranyl reduction may transpire through either biotic (enzymatic) or abiotic pathways; in either case, reduction of U(VI) to U(IV) results in the formation of sparingly soluble UO{sub 2} precipitates. Biological reduction of U(VI), while demonstrated as prolific under both laboratory and field conditions, is influenced by competing electron acceptors (such as nitrate, manganese oxides, or iron oxides) and uranyl speciation. Formation of Ca-UO{sub 2}-CO{sub 3} ternary complexes, often the predominate uranyl species in carbonate-bearing soils and sediments, decreases the rate of dissimilatory U(VI) reduction. Themore »« less
U(VI) Reduction by Biogenic and Abiotic Hydroxycarbonate Green Rusts: Impacts on U(IV) Speciation and Stability Over Time

Journal Article Yan, Sen ; Boyanov, Maxim I. ; Mishra, Bhoopesh ; ... - Environmental Science and Technology

Green rusts (GRs) are redox active Fe^II-Fe^III minerals that form in the environment via various biotic and abiotic processes. Although both biogenic (BioGR) and abiotic (ChemGR) GRs have been shown to reduce U^VI, the dynamics of the transformations and the speciation and stability of the resulting U^IV phases are poorly understood. We used carbonate extraction and XAFS spectroscopy to investigate the products of U^VI reduction by BioGR and ChemGR. The results show that both GRs can rapidly remove U^VI from synthetic groundwater via reduction to U^IV. The initial products in the ChemGR system are solids-associated U^IV-carbonate complexes that gradually transformmore »« less
Cited by 17
https://doi.org/10.1021/acs.est.7b06405

Full Text Available
Reductive immobilization of U(VI) in Fe(III) oxide-reducing subsurface sediments: Analysis of coupled microbial-geochemical processes in experimental reactive transport systems

Technical Report Roden, Eric E ; Barnett, Mark O

Although the fundamental microbiological and geochemical processes underlying the potential use of dissimilatory metal-reducing bacteria (DMRB) to create subsurface redox barriers for immobilization of uranium and other redox-sensitive metal/radionuclide contaminants are well-understood (Lovley et al., 1991; Gorby and Lovley, 1992; Lovley and Phillips, 1992; Lovley, 1995; Fredrickson et al., 2000; Wielinga et al., 2000; Wielinga et al., 2001), several fundamental scientific questions need to be addressed in order to understand and predict how such treatment procedures would function under in situ conditions in the subsurface. These questions revolve around the dynamic interactions between hydrologic flux and the coupled microbial-geochemical processesmore »« less
https://doi.org/10.2172/838637

Full Text Available

Similar Records

Title: Uranium isotope fractionation by abiotic reductive precipitation

Abstract

Citation Formats

Influence of Dynamical Conditions on the Reduction of U VI at the Magnetite−Solution Interface journal, January 2010

Isotopic Tracking of Hanford 300 Area Derived Uranium in the Columbia River journal, December 2010

Uranium reduction on magnetite: Probing for pentavalent uranium using electrochemical methods journal, May 2015

Exchange Reactions of Uranium Ions in Solution journal, October 1950

Isotope fractionation of 238U and 235U during biologically-mediated uranium reduction journal, August 2015

Low-temperature isotopic fractionation of uranium journal, December 2007

Mass Dependence of Uranium Isotope Effects in the U(IV)−U(VI) Exchange Reaction journal, January 1996

The thermodynamic properties of isotopic substances journal, January 1947

Experimentally Determined Uranium Isotope Fractionation During Reduction of Hexavalent U by Bacteria and Zero Valent Iron journal, November 2006

U(VI) Sorption and Reduction Kinetics on the Magnetite (111) Surface journal, March 2012

Calculation of Equilibrium Constants for Isotopic Exchange Reactions journal, May 1947

Uranyl(VI) carbonate complex formation: Validation of the Ca2UO2(CO3)3(aq.) species journal, January 2001

Reductive Immobilization of Uranium(VI) by Amorphous Iron Sulfide journal, December 2008

Effects of Solution Composition and pH on the Reductive Dechlorination of Hexachloroethane by Iron Sulfide journal, May 1998

Isotopic Evidence for Reductive Immobilization of Uranium Across a Roll-Front Mineral Deposit journal, June 2016

Uranium(VI) Reduction by Iron(II) Monosulfide Mackinawite journal, February 2012

Molybdenum Isotope Evidence for Widespread Anoxia in Mid-Proterozoic Oceans journal, April 2004

Uranium isotope fractionation induced by aqueous speciation: Implications for U isotopes in marine CaCO 3 as a paleoredox proxy journal, October 2017

Competition between enzymatic and abiotic reduction of uranium(VI) under iron reducing conditions journal, August 2005

Origin of uranium isotope variations in early solar nebula condensates journal, March 2016

Surface chemistry of disordered mackinawite (FeS) journal, July 2005

Abiotic Reductive Immobilization of U(VI) by Biogenic Mackinawite journal, February 2013

Uranium Isotope Fractionation journal, January 2017

FeS-coated sand for removal of arsenic(III) under anaerobic conditions in permeable reactive barriers journal, January 2011

Earth’s oxygen cycle and the evolution of animal life journal, July 2016

Environmental Speciation of Actinides journal, June 2012

Natural fractionation of 238U/235U journal, January 2008

Chemical Speciation of Uranium(VI) in Marine Environments: Complexation of Calcium and Magnesium Ions with [(UO 2 )(CO 3 ) 3 ] 4− and the Effect on the Extraction of Uranium from Seawater journal, September 2014

Optimal methods for estimating kinetic isotope effects from different forms of the Rayleigh distillation equation journal, February 2004

Determination of the Formation Constants of Ternary Complexes of Uranyl and Carbonate with Alkaline Earth Metals (Mg 2+ , Ca 2+ , Sr 2+ , and Ba 2+ ) Using Anion Exchange Method journal, August 2006

Fractionation of 238U/235U by reduction during low temperature uranium mineralisation processes journal, February 2014

Inhibition of Bacterial U(VI) Reduction by Calcium journal, May 2003

Uranium isotopic fractionation factors during U(VI) reduction by bacterial isolates journal, July 2014

Surface kinetic model for isotopic and trace element fractionation during precipitation of calcite from aqueous solutions journal, February 2011

Speciation-Dependent Kinetics of Uranium(VI) Bioreduction journal, June 2011

Uranium isotopes fingerprint biotic reduction journal, April 2015

Surface catalysis of uranium(VI) reduction by iron(II) journal, October 1999

Formation of ternary CaUO2(CO3)32− and Ca2UO2(CO3)3(aq) complexes under neutral to weakly alkaline conditions journal, January 2013

The effect of calcium on aqueous uranium(VI) speciation and adsorption to ferrihydrite and quartz journal, March 2006

Distinct 238 U/ 235 U ratios and REE patterns in plutonic and volcanic angrites: Geochronologic implications and evidence for U isotope fractionation during magmatic processes journal, September 2017

The solubility of FeS journal, December 2006

Isotope fractionation during oxidation of tetravalent uranium by dissolved oxygen journal, February 2015

Quantifying Constraints Imposed by Calcium and Iron on Bacterial Reduction of Uranium(VI) journal, January 2007

238U/235U Systematics in Terrestrial Uranium-Bearing Minerals journal, March 2012

Ion desolvation as a mechanism for kinetic isotope fractionation in aqueous systems journal, October 2012

Uranium stable isotope fractionation in the Black Sea: Modern calibration of the 238U/235U paleo-redox proxy journal, April 2017

Isotopic and Geochemical Tracers for U(VI) Reduction and U Mobility at an in Situ Recovery U Mine journal, May 2015

Uranium isotope fractionation during coprecipitation with aragonite and calcite journal, September 2016

Nuclear Size and Shape Effects in Chemical Reactions. Isotope Chemistry of the Heavy Elements journal, January 1996

Influence of Dynamical Conditions on the Reduction of U ^VI at the Magnetite−Solution Interface
journal, January 2010

Isotopic Tracking of Hanford 300 Area Derived Uranium in the Columbia River
journal, December 2010

Uranium reduction on magnetite: Probing for pentavalent uranium using electrochemical methods
journal, May 2015

Exchange Reactions of Uranium Ions in Solution
journal, October 1950

Isotope fractionation of 238U and 235U during biologically-mediated uranium reduction
journal, August 2015

Low-temperature isotopic fractionation of uranium
journal, December 2007

Mass Dependence of Uranium Isotope Effects in the U(IV)−U(VI) Exchange Reaction
journal, January 1996

The thermodynamic properties of isotopic substances
journal, January 1947

Experimentally Determined Uranium Isotope Fractionation During Reduction of Hexavalent U by Bacteria and Zero Valent Iron
journal, November 2006

U(VI) Sorption and Reduction Kinetics on the Magnetite (111) Surface
journal, March 2012

Calculation of Equilibrium Constants for Isotopic Exchange Reactions
journal, May 1947

Uranyl(VI) carbonate complex formation: Validation of the Ca2UO2(CO3)3(aq.) species
journal, January 2001

Reductive Immobilization of Uranium(VI) by Amorphous Iron Sulfide
journal, December 2008

Effects of Solution Composition and pH on the Reductive Dechlorination of Hexachloroethane by Iron Sulfide
journal, May 1998

Isotopic Evidence for Reductive Immobilization of Uranium Across a Roll-Front Mineral Deposit
journal, June 2016

Uranium(VI) Reduction by Iron(II) Monosulfide Mackinawite
journal, February 2012

Molybdenum Isotope Evidence for Widespread Anoxia in Mid-Proterozoic Oceans
journal, April 2004

Uranium isotope fractionation induced by aqueous speciation: Implications for U isotopes in marine CaCO 3 as a paleoredox proxy
journal, October 2017

Competition between enzymatic and abiotic reduction of uranium(VI) under iron reducing conditions
journal, August 2005

Origin of uranium isotope variations in early solar nebula condensates
journal, March 2016

Surface chemistry of disordered mackinawite (FeS)
journal, July 2005

Abiotic Reductive Immobilization of U(VI) by Biogenic Mackinawite
journal, February 2013

Uranium Isotope Fractionation
journal, January 2017

FeS-coated sand for removal of arsenic(III) under anaerobic conditions in permeable reactive barriers
journal, January 2011

Earth’s oxygen cycle and the evolution of animal life
journal, July 2016

Environmental Speciation of Actinides
journal, June 2012

Natural fractionation of 238U/235U
journal, January 2008

Chemical Speciation of Uranium(VI) in Marine Environments: Complexation of Calcium and Magnesium Ions with [(UO ₂ )(CO ₃ ) ₃ ] ⁴⁻ and the Effect on the Extraction of Uranium from Seawater
journal, September 2014

Optimal methods for estimating kinetic isotope effects from different forms of the Rayleigh distillation equation
journal, February 2004

Determination of the Formation Constants of Ternary Complexes of Uranyl and Carbonate with Alkaline Earth Metals (Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , and Ba ²⁺ ) Using Anion Exchange Method
journal, August 2006

Fractionation of 238U/235U by reduction during low temperature uranium mineralisation processes
journal, February 2014

Inhibition of Bacterial U(VI) Reduction by Calcium
journal, May 2003

Uranium isotopic fractionation factors during U(VI) reduction by bacterial isolates
journal, July 2014

Surface kinetic model for isotopic and trace element fractionation during precipitation of calcite from aqueous solutions
journal, February 2011

Speciation-Dependent Kinetics of Uranium(VI) Bioreduction
journal, June 2011

Uranium isotopes fingerprint biotic reduction
journal, April 2015

Surface catalysis of uranium(VI) reduction by iron(II)
journal, October 1999

Formation of ternary CaUO2(CO3)32− and Ca2UO2(CO3)3(aq) complexes under neutral to weakly alkaline conditions
journal, January 2013

The effect of calcium on aqueous uranium(VI) speciation and adsorption to ferrihydrite and quartz
journal, March 2006

Distinct 238 U/ 235 U ratios and REE patterns in plutonic and volcanic angrites: Geochronologic implications and evidence for U isotope fractionation during magmatic processes
journal, September 2017

The solubility of FeS
journal, December 2006

Isotope fractionation during oxidation of tetravalent uranium by dissolved oxygen
journal, February 2015

Quantifying Constraints Imposed by Calcium and Iron on Bacterial Reduction of Uranium(VI)
journal, January 2007

238U/235U Systematics in Terrestrial Uranium-Bearing Minerals
journal, March 2012

Ion desolvation as a mechanism for kinetic isotope fractionation in aqueous systems
journal, October 2012

Uranium stable isotope fractionation in the Black Sea: Modern calibration of the 238U/235U paleo-redox proxy
journal, April 2017

Isotopic and Geochemical Tracers for U(VI) Reduction and U Mobility at an in Situ Recovery U Mine
journal, May 2015

Uranium isotope fractionation during coprecipitation with aragonite and calcite
journal, September 2016

Nuclear Size and Shape Effects in Chemical Reactions. Isotope Chemistry of the Heavy Elements
journal, January 1996