1
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Bracco JN, Camacho Meneses G, Colón O, Yuan K, Stubbs JE, Eng PJ, Wanhala AK, Einkauf JD, Boebinger MG, Stack AG, Weber J. Reaction Layer Formation on MgO in the Presence of Humidity. ACS Appl Mater Interfaces 2024; 16:712-722. [PMID: 38157368 DOI: 10.1021/acsami.3c14823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Mineralization by MgO is an attractive potential strategy for direct air capture (DAC) of CO2 due to its tendency to form carbonate phases upon exposure to water and CO2. Hydration of MgO during this process is typically assumed to not be rate limiting, even at ambient temperatures. However, surface passivation by hydrated phases likely reduces the CO2 capture capacity. Here, we examine the initial hydration reactions that occur on MgO(100) surfaces to determine whether they could potentially impact CO2 uptake. We first used atomic force microscopy (AFM) to explore changes in reaction layers in water (pH = 6 and 12) and MgO-saturated solution (pH = 11) and found the reaction layers on MgO are heterogeneous and nonuniform. To determine how relative humidity (R.H.) affects reactivity, we reacted samples at room temperature in nominally dry N2 (∼11-12% R.H.) for up to 12 h, in humid (>95% R.H.) N2 for 5, 10, and 15 min, and in air at 33 and 75% R.H. for 8 days. X-ray reflectivity and electron microscopy analysis of the samples reveal that hydrated phases form rapidly upon exposure to humid air, but the growth of the hydrated reaction layer slows after its initial formation. Reaction layer thickness is strongly correlated with R.H., with denser reaction layers forming in 75% R.H. compared with 33% R.H. or nominally dry N2. The reaction layers are likely amorphous or poorly crystalline based on grazing incidence X-ray diffraction measurements. After exposure to 75% R.H. in air for 8 days, the reaction layer increases in density as compared to the sample reacted in humid N2 for 5-15 min. This may represent an initial step toward the crystallization of the reaction layer. Overall, high R.H. favors the formation of a hydrated, disordered layer on MgO. Based on our results, DAC in a location with a higher R.H. will be favorable, but growth may slow significantly from initial rates even on short timescales, presumably due to surface passivation.
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Affiliation(s)
- Jacquelyn N Bracco
- School of Earth and Environmental Sciences, Queens College, City University of New York, Queens, New York 11367-0904, United States
- Earth and Environmental Sciences, Graduate Center, City University of New York, New York, New York 10016-4309, United States
| | - Gabriela Camacho Meneses
- School of Earth and Environmental Sciences, Queens College, City University of New York, Queens, New York 11367-0904, United States
| | - Omar Colón
- School of Earth and Environmental Sciences, Queens College, City University of New York, Queens, New York 11367-0904, United States
| | - Ke Yuan
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Joanne E Stubbs
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Peter J Eng
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
- James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - Anna K Wanhala
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, Illinois 60637, United States
| | - Jeffrey D Einkauf
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Matthew G Boebinger
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Andrew G Stack
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Juliane Weber
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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2
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Neumann J, Lessing J, Lee SS, Stubbs JE, Eng PJ, Demnitz M, Fenter P, Schmidt M. Y(III) Sorption at the Orthoclase (001) Surface Measured by X-ray Reflectivity. Environ Sci Technol 2023; 57:266-276. [PMID: 36562683 DOI: 10.1021/acs.est.2c06703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Interactions of heavy metals with charged mineral surfaces control their mobility in the environment. Here, we investigate the adsorption of Y(III) onto the orthoclase (001) basal plane, the former as a representative of rare earth elements and an analogue of trivalent actinides and the latter as a representative of naturally abundant K-feldspar minerals. We apply in situ high-resolution X-ray reflectivity to determine the sorption capacity and molecular distribution of adsorbed Y species as a function of the Y3+ concentration, [Y3+], at pH 7 and 5. With [Y3+] ≥ 1 mM at pH 7, we observe an inner-sphere (IS) sorption complex at a distance of ∼1.5 Å from the surface and an outer-sphere (OS) complex at 3-4 Å. Based on the adsorption height of the IS complex, a bidentate, binuclear binding mode, in which Y3+ binds to two terminal oxygens, is proposed. In contrast, mostly OS sorption is observed at pH 5. The observed maximum Y coverage is ∼1.3 Y3+/AUC (AUC: area of the unit cell = 111.4 Å2) for all the investigated pH values and Y concentrations, which is in the expected range based on the estimated surface charge of orthoclase (001).
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Affiliation(s)
- Julia Neumann
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, Dresden01328, Germany
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois60439, United States
| | - Jessica Lessing
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, Dresden01328, Germany
| | - Sang Soo Lee
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois60439, United States
| | - Joanne E Stubbs
- Center for Advanced Radiation Sources, The University of Chicago, 929 E 57th Street, Chicago, Illinois60637, United States
| | - Peter J Eng
- Center for Advanced Radiation Sources, The University of Chicago, 929 E 57th Street, Chicago, Illinois60637, United States
- James Franck Institute, The University of Chicago, 929 E 57th Street, Chicago, Illinois60637, United States
| | - Maximilian Demnitz
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, Dresden01328, Germany
| | - Paul Fenter
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois60439, United States
| | - Moritz Schmidt
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, Dresden01328, Germany
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3
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Heberling F, Klačić T, Raiteri P, Gale JD, Eng PJ, Stubbs JE, Gil-Díaz T, Begović T, Lützenkirchen J. Structure and Surface Complexation at the Calcite(104)-Water Interface. Environ Sci Technol 2021; 55:12403-12413. [PMID: 34478280 DOI: 10.1021/acs.est.1c03578] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Calcite is the most stable polymorph of calcium carbonate (CaCO3) under ambient conditions and is ubiquitous in natural systems. It plays a major role in controlling pH in environmental settings. Electrostatic phenomena at the calcite-water interface and the surface reactivity of calcite in general have important environmental implications. They may strongly impact nutrient and contaminant mobility in soils and other subsurface environments, they control oil recovery from limestone reservoirs, and they may impact the safety of nuclear waste disposal sites. Besides the environmental relevance, the topic is significant for industrial applications and cultural heritage preservation. In this study, the structure of the calcite(104)-water interface is investigated on the basis of a new extensive set of crystal truncation rod data. The results agree with recently reported structures and resolve previous ambiguities with respect to the coordination sphere of surface Ca ions. These structural features are introduced into an electrostatic three-plane surface complexation model, describing ion adsorption and charging at the calcite-water interface. Inner surface potential data for calcite, as measured with a calcite single-crystal electrode, are used as constraints for the model in addition to zeta potential data. Ion adsorption parameters are compared with molecular dynamics simulations. All model parameters, including protonation constants, ion-binding parameters, and Helmholtz capacitances, are within physically and chemically plausible ranges. A PhreeqC version of the model is presented, which we hope will foster application of the model in environmental studies.
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Affiliation(s)
- Frank Heberling
- Institute for Nuclear Waste Disposal, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
| | - Tin Klačić
- Division of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102A, HR-10000 Zagreb, Croatia
| | - Paolo Raiteri
- Curtin Institute for Computation/The Institute for Geoscience Research, School of Molecular and Life Sciences, Curtin University, P.O. Box U1987 Perth, WA 6845, Australia
| | - Julian D Gale
- Curtin Institute for Computation/The Institute for Geoscience Research, School of Molecular and Life Sciences, Curtin University, P.O. Box U1987 Perth, WA 6845, Australia
| | - Peter J Eng
- Center for Advanced Radiation Sources, The University of Chicago, 5734 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Joanne E Stubbs
- Center for Advanced Radiation Sources, The University of Chicago, 5734 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Teba Gil-Díaz
- Institute for Nuclear Waste Disposal, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
- Institute of Geosciences, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749 Jena, Germany
| | - Tajana Begović
- Division of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102A, HR-10000 Zagreb, Croatia
| | - Johannes Lützenkirchen
- Institute for Nuclear Waste Disposal, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe, Germany
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Qiu C, Eng PJ, Hennig C, Schmidt M. Competitive Adsorption of ZrO 2 Nanoparticle and Alkali Cations (Li +-Cs +) on Muscovite (001). Langmuir 2018; 34:12270-12278. [PMID: 30217107 DOI: 10.1021/acs.langmuir.8b02277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We studied the adsorption behavior of ZrO2 nanoparticles on a muscovite (001) surface in the presence of cations from the alkali series (Li+, Na+, K+, Rb+, and Cs+). The results of X-ray reflectivity, i.e., specular crystal truncation rod and resonant anomalous X-ray reflectivity in combination with AFM images, show that the sorption of ZrO2 nanoparticles is significantly affected by the binding mode of alkali ions on the muscovite (001) surface. From solutions containing alkali ions binding as outer sphere surface complexes (i.e., Li+ and Na+), higher uptake of Zr4+ is observed corresponding to the binding of larger nanoparticles, which relatively easily replace the loosely bound alkali ions. However, Zr4+ uptake in solutions containing alkali ions binding as inner sphere surface complexes (i.e., K+, Rb+, and Cs+) is significantly lower, and smaller nanoparticles are found at the interface. In addition, the uptake of Zr4+ in the presence of inner sphere bound cations displays a strong linear relationship with the hydration energy of the coexisting alkali ion. The linear trend can be interpreted as competitive adsorption between ZrO2 nanoparticles and inner sphere bound alkali cations, which are replaced on the surface and undergo rehydration after release to the solution. The rehydration of alkali ions gives rise to a large energy gain, which dominates the reaction energy of the competitive adsorption process. The competitive adsorption mechanism of ZrO2 nanoparticles and alkali ions is discussed comprehensively to highlight the potential relationship between the hydration effect of alkali ions and the effect of charge density of the nanoparticles.
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Affiliation(s)
- Canrong Qiu
- Institute of Resource Ecology , Helmholtz-Zentrum Dresden-Rossendorf , Dresden 01328 , Germany
| | - Peter J Eng
- Center for Advanced Radiation Sources , University of Chicago , Chicago , Illinois 60637 , United States
| | - Christoph Hennig
- Institute of Resource Ecology , Helmholtz-Zentrum Dresden-Rossendorf , Dresden 01328 , Germany
| | - Moritz Schmidt
- Institute of Resource Ecology , Helmholtz-Zentrum Dresden-Rossendorf , Dresden 01328 , Germany
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5
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Qiu C, Majs F, Eng PJ, Stubbs JE, Douglas TA, Schmidt M, Trainor TP. In situ structural study of the surface complexation of lead(II) on the chemically mechanically polished hematite (11¯02) surface. J Colloid Interface Sci 2018; 524:65-75. [PMID: 29631220 DOI: 10.1016/j.jcis.2018.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 03/23/2018] [Accepted: 04/02/2018] [Indexed: 11/26/2022]
Abstract
A structural study of the surface complexation of Pb(II) on the (11¯02) surface of hematite was undertaken using crystal truncation rod (CTR) X-ray diffraction measurements under in situ conditions. The sorbed Pb was found to form inner sphere (IS) complexes at two types of edge-sharing sites on the half layer termination of the hematite (11¯02) surface. The best fit model contains Pb in distorted trigonal pyramids with an average PbO bond length of 2.27(4) Å and two characteristic Pb-Fe distances of 3.19(1) Å and 3.59(1) Å. In addition, a site coverage model was developed to simulate coverage as a function of sorbate-sorbate distance. The simulation results suggest a plausible Pb-Pb distance of 5.42 Å, which is slightly larger than the diameter of Pb's first hydration shell. This relates the best fit surface coverage of 0.59(4) Pb per unit cell at monolayer saturation to steric constraints as well as electrostatic repulsion imposed by the hydrated Pb complex. Based on the structural results we propose a stoichiometry of the surface complexation reaction of Pb(II) on the hematite (11¯02) surface and use bond valence analysis to assign the protonation schemes of surface oxygens. Surface reaction stoichiometry suggests that the proton release in the course of surface complexation occurs from the Pb-bound surface O atoms at pH 5.5.
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Affiliation(s)
- Canrong Qiu
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, USA.
| | - Frantisek Majs
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Peter J Eng
- Center for Advanced Radiation Sources, University of Chicago, Chicago, IL, USA
| | - Joanne E Stubbs
- Center for Advanced Radiation Sources, University of Chicago, Chicago, IL, USA
| | - Thomas A Douglas
- U.S. Army Cold Regions Research and Engineering Laboratory, Fort Wainwright, AK, USA
| | - Moritz Schmidt
- Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Dresden, Germany
| | - Thomas P Trainor
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, USA
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6
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Stubbs JE, Biwer CA, Chaka AM, Ilton ES, Du Y, Bargar JR, Eng PJ. Oxidative Corrosion of the UO 2 (001) Surface by Nonclassical Diffusion. Langmuir 2017; 33:13189-13196. [PMID: 29084427 DOI: 10.1021/acs.langmuir.7b02800] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Uranium oxide is central to every stage of the nuclear fuel cycle, from mining through fuel fabrication and use, to waste disposal and environmental cleanup. Its chemical and mechanical stability are intricately linked to the concentration of interstitial O atoms within the structure and the oxidation state of U. We have previously shown that, during corrosion of the UO2 (111) surface under either 1 atm of O2 gas or oxygenated water at room temperature, oxygen interstitials diffuse into the substrate to form a superlattice with three-layer periodicity. In the current study, we present results from surface X-ray scattering that reveal the structure of the oxygen diffusion profile beneath the (001) surface. The first few layers below the surface oscillate strongly in their surface-normal lattice parameters, suggesting preferential interstitial occupation of every other layer below the surface, which is geometrically consistent with the interstitial network that forms below the oxidized (111) surface. Deeper layers are heavily contracted and indicate that the oxidation front penetrates ∼52 Å below the (001) surface after 21 days of dry O2 gas exposure at ambient pressure and temperature. X-ray photoelectron spectroscopy indicates U is present as U(IV), U(V), and U(VI).
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Affiliation(s)
| | | | - Anne M Chaka
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Eugene S Ilton
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Yingge Du
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - John R Bargar
- Stanford Synchrotron Radiation Lightsource, Menlo Park, California 94025, United States
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7
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McBriarty ME, von Rudorff GF, Stubbs JE, Eng PJ, Blumberger J, Rosso KM. Dynamic Stabilization of Metal Oxide–Water Interfaces. J Am Chem Soc 2017; 139:2581-2584. [DOI: 10.1021/jacs.6b13096] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Martin E. McBriarty
- Physical
Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | | | - Joanne E. Stubbs
- Center
for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60439, United States
| | - Peter J. Eng
- Center
for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60439, United States
| | - Jochen Blumberger
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Kevin M. Rosso
- Physical
Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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8
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Abstract
In this report we describe detailed procedures for carrying out single crystal X-ray diffraction experiments with a diamond anvil cell (DAC) at the GSECARS 13-BM-C beamline at the Advanced Photon Source. The DAC program at 13-BM-C is part of the Partnership for Extreme Xtallography (PX^2) project. BX-90 type DACs with conical-type diamond anvils and backing plates are recommended for these experiments. The sample chamber should be loaded with noble gas to maintain a hydrostatic pressure environment. The sample is aligned to the rotation center of the diffraction goniometer. The MARCCD area detector is calibrated with a powder diffraction pattern from LaB6. The sample diffraction peaks are analyzed with the ATREX software program, and are then indexed with the RSV software program. RSV is used to refine the UB matrix of the single crystal, and with this information and the peak prediction function, more diffraction peaks can be located. Representative single crystal diffraction data from an omphacite (Ca0.51Na0.48)(Mg0.44Al0.44Fe2+0.14Fe3+0.02)Si2O6 sample were collected. Analysis of the data gave a monoclinic lattice with P2/n space group at 0.35 GPa, and the lattice parameters were found to be: a = 9.496 ±0.006 Å, b = 8.761 ±0.004 Å, c = 5.248 ±0.001 Å, β = 105.06 ±0.03º, α = γ = 90º.
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Affiliation(s)
- Dongzhou Zhang
- Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Manoa;
| | - Przemyslaw K Dera
- Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Manoa
| | - Peter J Eng
- Center for Advanced Radiation Sources, University of Chicago
| | - Joanne E Stubbs
- Center for Advanced Radiation Sources, University of Chicago
| | - Jin S Zhang
- Hawai'i Institute of Geophysics and Planetology, University of Hawai'i at Manoa
| | | | - Mark L Rivers
- Center for Advanced Radiation Sources, University of Chicago
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9
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Ilton ES, Du Y, Stubbs JE, Eng PJ, Chaka AM, Bargar JR, Nelin CJ, Bagus PS. Quantifying small changes in uranium oxidation states using XPS of a shallow core level. Phys Chem Chem Phys 2017; 19:30473-30480. [DOI: 10.1039/c7cp05805e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Quantification of U(iv), U(v), and U(vi) in UO2+x using the 5d XPS.
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Affiliation(s)
| | - Yingge Du
- Pacific Northwest National Laboratory
- Richland
- USA
| | - Joanne E. Stubbs
- Center for Advanced Radiation Sources
- University of Chicago
- Chicago
- USA
| | - Peter J. Eng
- Center for Advanced Radiation Sources
- University of Chicago
- Chicago
- USA
- James Franck Institute
| | | | | | | | - Paul S. Bagus
- Department of Chemistry
- University of North Texas
- Denton
- USA
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10
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Hellebrandt S, Lee SS, Knope KE, Lussier AJ, Stubbs JE, Eng PJ, Soderholm L, Fenter P, Schmidt M. A Comparison of Adsorption, Reduction, and Polymerization of the Plutonyl(VI) and Uranyl(VI) Ions from Solution onto the Muscovite Basal Plane. Langmuir 2016; 32:10473-10482. [PMID: 27678146 DOI: 10.1021/acs.langmuir.6b02513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
X-ray scattering techniques [in situ resonant anomalous X-ray reflectivity (RAXR) and specular crystal truncation rods (CTR)] were used to compare muscovite (001) surfaces in contact with solutions containing either 0.1 mM plutonyl(VI) or 1 mM uranyl(VI) at pH = 3.2 ± 0.2, I(NaCl) = 0.1 M, as well as in situ grazing-incidence X-ray absorption near-edge structure (GI XANES) spectroscopy and ex situ alpha spectrometry. Details of the surface coverage are found to be very different. In the case of Pu, alpha spectrometry finds a surface coverage of 8.3 Pu/AUC (AUC = 46.72 Å2, the unit cell area), far in excess of the 0.5 Pu/AUC expected for ionic adsorption of PuO22+. GI XANES results show that Pu is predominantly tetravalent on the surface, and the CTR/RAXR results show that the adsorbed Pu is broadly distributed. Taken together with previous findings, the results are consistent with adsorption of Pu in the form of Pu(IV)-oxo-nanoparticles. In contrast, uranyl shows only negligible, if any, adsorption according to all methods applied. These results are discussed and compared within the context of known Pu and U redox chemistry.
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Affiliation(s)
- Stefan Hellebrandt
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf , Dresden 01314, Germany
| | - Sang Soo Lee
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Karah E Knope
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Aaron J Lussier
- Department of Civil & Environmental Engineering & Earth Sciences, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Joanne E Stubbs
- Center for Advanced Radiation Sources, University of Chicago , Chicago, Illinois 60637, United States
| | - Peter J Eng
- Center for Advanced Radiation Sources, University of Chicago , Chicago, Illinois 60637, United States
| | - L Soderholm
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Paul Fenter
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Moritz Schmidt
- Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf , Dresden 01314, Germany
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11
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Lützenkirchen J, Heberling F, Supljika F, Preocanin T, Kallay N, Johann F, Weisser L, Eng PJ. Structure–charge relationship – the case of hematite (001). Faraday Discuss 2015; 180:55-79. [DOI: 10.1039/c4fd00260a] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We present a multidisciplinary study on the hematite (001)–aqueous solution interface, in particular the relationship between surface structure (studiedviasurface diffraction in a humid atmosphere) and the macroscopic charging (studiedviasurface- and zeta-potential measurements in electrolyte solutions as a function of pH). Upon aging in water changes in the surface structure are observed, that are accompanied by drastic changes in the zeta-potential. Surprisingly the surface potential is not accordingly affected. We interpret our results by increasing hydration of the surface with time and enhanced reactivity of singly-coordinated hydroxyl groups that cause the isoelectric point of the surface to shift to values that are reminiscent of those typically reported for hematite particles. In its initial stages after preparation the hematite surface is very flat and only weakly hydrated. Our model links the entailing weak water structure with the observed low isoelectric point reminiscent of hydrophobic surfaces. The absence of an aging effect on the surface potentialvs.pH curves is interpreted as domination of the surface potential by the doubly coordinated hydroxyls, which are present on both surfaces.
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Affiliation(s)
- Johannes Lützenkirchen
- Institut für Nukleare Entsorgung
- Karlsruhe Institut für Technologie
- 76021 Karlsruhe
- Germany
| | - Frank Heberling
- Institut für Nukleare Entsorgung
- Karlsruhe Institut für Technologie
- 76021 Karlsruhe
- Germany
| | - Filip Supljika
- Laboratory of Physical Chemistry
- Department of Chemistry
- Faculty of Science
- University of Zagreb
- 10001 Zagreb
| | - Tajana Preocanin
- Laboratory of Physical Chemistry
- Department of Chemistry
- Faculty of Science
- University of Zagreb
- 10001 Zagreb
| | - Nikola Kallay
- Laboratory of Physical Chemistry
- Department of Chemistry
- Faculty of Science
- University of Zagreb
- 10001 Zagreb
| | - Florian Johann
- Oxford Instruments GmbH, c/o Asylum Research
- DE-68259 Mannheim
- Germany
| | - Ludger Weisser
- Oxford Instruments GmbH, c/o Asylum Research
- DE-68259 Mannheim
- Germany
| | - Peter J. Eng
- GeoSoilEnviroCars
- University of Chicago
- Chicago
- USA
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12
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Schmidt M, Lee SS, Wilson RE, Knope KE, Bellucci F, Eng PJ, Stubbs JE, Soderholm L, Fenter P. Surface-mediated formation of Pu(IV) nanoparticles at the muscovite-electrolyte interface. Environ Sci Technol 2013; 47:14178-14184. [PMID: 24266655 DOI: 10.1021/es4037258] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The formation of Pu(IV)-oxo-nanoparticles from Pu(III) solutions by a surface-enhanced redox/polymerization reaction at the muscovite (001) basal plane is reported, with a continuous increase in plutonium coverage observed in situ over several hours. The sorbed Pu extends >70 Å from the surface with a maximum concentration at 10.5 Å and a total coverage of >9 Pu atoms per unit cell area of muscovite (0.77 μg Pu/cm(2)) (determined independently by in situ resonant anomalous X-ray reflectivity and by ex-situ alpha-spectrometry). The presence of discrete nanoparticles is confirmed by high resolution atomic force microscopy. We propose that the formation of these Pu(IV) nanoparticles from an otherwise stable Pu(III) solution can be explained by the combination of a highly concentrated interfacial Pu-ion species, the Pu(III)-Pu(IV) redox equilibrium, and the strong proclivity of tetravalent Pu to hydrolyze and form polymeric species. These results are the first direct observation of such behavior of plutonium on a naturally occurring mineral, providing insights into understanding the environmental transport of plutonium and other contaminants capable of similar redox/polymerization reactions.
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Affiliation(s)
- Moritz Schmidt
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne , Illinois 60439, United States
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13
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Wang Y, Michel FM, Levard C, Choi Y, Eng PJ, Brown GE. Competitive sorption of Pb(II) and Zn(II) on polyacrylic acid-coated hydrated aluminum-oxide surfaces. Environ Sci Technol 2013; 47:12131-12139. [PMID: 24024496 DOI: 10.1021/es401353y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Natural organic matter (NOM) often forms coatings on minerals. Such coatings are expected to affect metal-ion sorption due to abundant sorption sites in NOM and potential modifications to mineral surfaces, but such effects are poorly understood in complex multicomponent systems. Using poly(acrylic acid) (PAA), a simplified analog of NOM containing only carboxylic groups, Pb(II) and Zn(II) partitioning between PAA coatings and α-Al2O3 (1-102) and (0001) surfaces was investigated using long-period X-ray standing wave-florescence yield spectroscopy. In the single-metal-ion systems, PAA was the dominant sink for Pb(II) and Zn(II) for α-Al2O3(1-102) (63% and 69%, respectively, at 0.5 μM metal ions and pH 6.0). In equi-molar mixed-Pb(II)-Zn(II) systems, partitioning of both ions onto α-Al2O3(1-102) decreased compared with the single-metal-ion systems; however, Zn(II) decreased Pb(II) sorption to a greater extent than vice versa, suggesting that Zn(II) outcompeted Pb(II) for α-Al2O3(1-102) sorption sites. In contrast, >99% of both metal ions sorbed to PAA when equi-molar Pb(II) and Zn(II) were added simultaneously to PAA/α-Al2O3(0001). PAA outcompeted both α-Al2O3 surfaces for metal sorption but did not alter their intrinsic order of reactivity. This study suggests that single-metal-ion sorption results cannot be used to predict multimetal-ion sorption at NOM/metal-oxide interfaces when NOM is dominated by carboxylic groups.
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Affiliation(s)
- Yingge Wang
- Surface & Aqueous Geochemistry Group, Department of Geological & Environmental Sciences, Stanford University , Stanford, California 94305-2115, United States
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14
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Schmidt M, Eng PJ, Stubbs JE, Fenter P, Soderholm L. A new x-ray interface and surface scattering environmental cell design for in situ studies of radioactive and atmosphere-sensitive samples. Rev Sci Instrum 2011; 82:075105. [PMID: 21806225 DOI: 10.1063/1.3605484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present a novel design of a purpose-built, portable sample cell for in situ x-ray scattering experiments of radioactive or atmosphere sensitive samples. The cell has a modular design that includes two independent layers of containment that are used simultaneously to isolate the sensitive samples. Both layers of containment can be flushed with an inert gas, thus serving a double purpose as containment of radiological material (either as a solid sample or as a liquid phase) and in separating reactive samples from the ambient atmosphere. A remote controlled solution flow system is integrated into the containment system that allows sorption experiments to be performed on the diffractometer. The cell's design is discussed in detail and we demonstrate the cell's performance by presenting first results of crystal truncation rod measurements. The results were obtained from muscovite mica single crystals reacted with 1 mM solutions of Th(IV) with 0.1 M NaCl background electrolyte. Data were obtained in specular as well as off-specular geometry.
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Affiliation(s)
- M Schmidt
- Argonne National Laboratory, Chemical Sciences and Engineering Division, Argonne, Illinois 60439, USA.
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15
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Wall AJ, Heaney PJ, Mathur R, Post JE, Hanson JC, Eng PJ. A flow-through reaction cell that couples time-resolved X-ray diffraction with stable isotope analysis. J Appl Crystallogr 2011. [DOI: 10.1107/s0021889811000525] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A non-metallic flow-through reaction cell is described, designed forin situtime-resolved X-ray diffraction coupled with stable isotope analysis. The experimental setup allows the correlation of Cu isotope fractionation with changes in crystal structure during copper sulfide dissolution. This flow-through cell can be applied to many classes of fluid–mineral reactions that involve dissolution or ion exchange.
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16
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Meng Y, Eng PJ, Tse JS, Shaw DM, Hu MY, Shu J, Gramsch SA, Kao C, Hemley RJ, Mao HK. Inelastic x-ray scattering of dense solid oxygen: evidence for intermolecular bonding. Proc Natl Acad Sci U S A 2008; 105:11640-4. [PMID: 18687889 PMCID: PMC2575322 DOI: 10.1073/pnas.0805601105] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Indexed: 11/18/2022] Open
Abstract
The detailing of the intermolecular interactions in dense solid oxygen is essential for an understanding of the rich polymorphism and remarkable properties of this element at high pressure. Synchrotron inelastic x-ray scattering measurements of oxygen K-edge excitations to 38 GPa reveal changes in electronic structure and bonding on compression of the molecular solid. The measurements show that O(2) molecules interact predominantly through the half-filled 1pi(g)* orbital <10 GPa. Enhanced intermolecular interactions develop because of increasing overlap of the 1pi(g)* orbital in the low-pressure phases, leading to electron delocalization and ultimately intermolecular bonding between O(2) molecules at the transition to the epsilon-phase. The epsilon-phase, which consists of (O(2))(4) clusters, displays the bonding characteristics of a closed-shell system. Increasing interactions between (O(2))(4) clusters develop upon compression of the epsilon-phase, and provide a potential mechanism for intercluster bonding in still higher-pressure phases.
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Affiliation(s)
- Yue Meng
- High-Pressure Collaborative Access Team, Carnegie Institution of Washington, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
| | - Peter J. Eng
- Consortium for Advanced Radiation Source, University of Chicago, 9700 South Cass Avenue, Argonne, IL 60439
| | - John S. Tse
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, SK, Canada S7N 5E2
| | - Dawn M. Shaw
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, SK, Canada S7N 5E2
| | - Michael Y. Hu
- High-Pressure Collaborative Access Team, Carnegie Institution of Washington, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
| | - Jinfu Shu
- Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, Washington, DC 20015; and
| | - Stephen A. Gramsch
- Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, Washington, DC 20015; and
| | - Chichang Kao
- National Synchrotron Light Source, Brookhaven National Laboratory, P. O. Box 5000, Upton, NY 11973
| | - Russell J. Hemley
- Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, Washington, DC 20015; and
| | - Ho-kwang Mao
- High-Pressure Collaborative Access Team, Carnegie Institution of Washington, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439
- Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, Washington, DC 20015; and
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17
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Royer JR, Corwin EI, Conyers B, Flior A, Rivers ML, Eng PJ, Jaeger HM. Birth and growth of a granular jet. Phys Rev E Stat Nonlin Soft Matter Phys 2008; 78:011305. [PMID: 18763946 DOI: 10.1103/physreve.78.011305] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2007] [Indexed: 05/26/2023]
Abstract
The interaction between fine grains and the surrounding interstitial gas in a granular bed can lead to qualitatively new phenomena not captured in a simple, single-fluid model of granular flows. This is demonstrated by the granular jet formed by the impact of a solid sphere into a bed of loose, fine sand. Unlike jets formed by impact in fluids, this jet is actually composed of two separate components, an initial thin jet formed by the collapse of the cavity left by the impacting object stacked on top of a second, thicker jet which depends strongly on the ambient gas pressure. This complex structure is the result of an interplay between ambient gas, bed particles, and impacting sphere. Here we present the results of systematic experiments that combine measurements of the jet above the surface varying the release height, sphere diameter, container size, and bed material with x-ray radiography below the surface to connect the changing response of the bed to the changing structure of the jet. We find that the interstitial gas trapped by the low permeability of a fine-grained bed plays two distinct roles in the formation of the jet. First, gas trapped and compressed between grains prevents compaction, causing the bed to flow like an incompressible fluid and allowing the impacting object to sink deep into the bed. Second, the jet is initiated by the gravity driven collapse of the cavity left by the impacting object. If the cavity is large enough, gas trapped and compressed by the collapsing cavity can amplify the jet by directly pushing bed material upwards and creating the thick jet. As a consequence of these two factors, when the ambient gas pressure is decreased, there is a crossover from a nearly incompressible, fluidlike response of the bed to a highly compressible, dissipative response. Compaction of the bed at reduced pressure reduces the final depth of the impacting object, resulting in a smaller cavity and in the demise of the thick jet.
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Affiliation(s)
- John R Royer
- James Franck Institute and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
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18
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Lee SK, Lin JF, Cai YQ, Hiraoka N, Eng PJ, Okuchi T, Mao HK, Meng Y, Hu MY, Chow P, Shu J, Li B, Fukui H, Lee BH, Kim HN, Yoo CS. X-ray Raman scattering study of MgSiO3 glass at high pressure: implication for triclustered MgSiO3 melt in Earth's mantle. Proc Natl Acad Sci U S A 2008; 105:7925-9. [PMID: 18535140 PMCID: PMC2413174 DOI: 10.1073/pnas.0802667105] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Indexed: 11/18/2022] Open
Abstract
Silicate melts at the top of the transition zone and the core-mantle boundary have significant influences on the dynamics and properties of Earth's interior. MgSiO3-rich silicate melts were among the primary components of the magma ocean and thus played essential roles in the chemical differentiation of the early Earth. Diverse macroscopic properties of silicate melts in Earth's interior, such as density, viscosity, and crystal-melt partitioning, depend on their electronic and short-range local structures at high pressures and temperatures. Despite essential roles of silicate melts in many geophysical and geodynamic problems, little is known about their nature under the conditions of Earth's interior, including the densification mechanisms and the atomistic origins of the macroscopic properties at high pressures. Here, we have probed local electronic structures of MgSiO3 glass (as a precursor to Mg-silicate melts), using high-pressure x-ray Raman spectroscopy up to 39 GPa, in which high-pressure oxygen K-edge features suggest the formation of tricluster oxygens (oxygen coordinated with three Si frameworks; 3O) between 12 and 20 GPa. Our results indicate that the densification in MgSiO3 melt is thus likely to be accompanied with the formation of triculster, in addition to a reduction in nonbridging oxygens. The pressure-induced increase in the fraction of oxygen triclusters >20 GPa would result in enhanced density, viscosity, and crystal-melt partitioning, and reduced element diffusivity in the MgSiO3 melt toward deeper part of the Earth's lower mantle.
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Affiliation(s)
- Sung Keun Lee
- School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, Korea.
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19
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Royer JR, Corwin EI, Eng PJ, Jaeger HM. Gas-mediated impact dynamics in fine-grained granular materials. Phys Rev Lett 2007; 99:038003. [PMID: 17678330 DOI: 10.1103/physrevlett.99.038003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Indexed: 05/16/2023]
Abstract
Noncohesive granular media exhibit complex responses to sudden impact that often differ from those of ordinary solids and liquids. We investigate how this response is mediated by the presence of interstitial gas between the grains. Using high-speed x-ray radiography we track the motion of a steel sphere through the interior of a bed of fine, loose granular material. We find a crossover from nearly incompressible, fluidlike behavior at atmospheric pressure to a highly compressible, dissipative response once most of the gas is evacuated. We discuss these results in light of recent proposals for the drag force in granular media.
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Affiliation(s)
- John R Royer
- James Franck Institute and Department of Physics, The University of Chicago, Chicago, Illinois 60637, USA
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20
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Abstract
The three-dimensional structure of the hydrated (1014) surface of MnCO3 at 90% relative humidity and 295 K is determined from measurements of X-ray scattering along ten crystal-truncation rods (CTRs). The scattering data provide both vertical and lateral information about the interfacial structure. The model that best fits the scattering data is a surface having a first layer of manganese carbonate and an overlayer of oxygen (as water). Within the measurement uncertainty, the overlayer of oxygen (O(w)) and the first-layer of manganese (Mn1) have equal occupancies of 0.84. The Mn1-O(w) distance between these layers is 2.59 +/- 0.04 angstroms. The overlayer O atoms are displaced laterally by 0.157 angstroms in the x- and 0.626 angstroms in the y-direction relative to the first-layer Mn atoms. The first-layer carbonate groups tilt by -4.2 +/- 2.1 degrees in phi (toward the surface plane) and -2.6 +/- 1.2 degrees in chi (an axis perpendicular to phi). The second-layer carbonate groups do not tilt, at least within measurement uncertainty. The spacing between Mn atom layers remains unchanged within measurement error whereas the spacing between layers of C atoms in carbonate contracts for the top three layers. Knowledge of the detailed atomic structure of the hydrated (1014) surface of MnCO3 provides a structural baseline for the interpretation of chemical reactivity.
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Affiliation(s)
- Young-Shin Jun
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
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21
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Lee SK, Eng PJ, Mao HK, Meng Y, Shu J. Structure of alkali borate glasses at high pressure: B and Li K-edge inelastic X-ray scattering study. Phys Rev Lett 2007; 98:105502. [PMID: 17358545 DOI: 10.1103/physrevlett.98.105502] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Indexed: 05/14/2023]
Abstract
We report the first in situ boron K-edge inelastic x-ray scattering (IXS) spectra for alkali borate glasses (Li2B4O7) at high pressure up to 30 GPa where pressure-induced coordination transformation from three-coordinated to four-coordinated boron was directly probed. Coordination transformation (reversible upon decompression) begins around 5 GPa and the fraction of four-coordinated boron increases with pressure from about 50% (at 1 atm) to more than 95% (at 30 GPa) with multiple densification mechanisms, evidenced by three distinct pressure ranges for (d[4]B/dP)T. The lithium K-edge IXS spectrum for Li-borate glasses at 5 GPa shows IXS features similar to that at 1 atm, suggesting that the Li environment does not change much with pressure up to 5 GPa. These results provide improved understanding of the structure of low-z glass at high pressure.
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Affiliation(s)
- Sung Keun Lee
- School of Earth and Environmental Sciences, Seoul National University, Seoul, 151-742 Korea.
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22
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Mao WL, Mao HK, Meng Y, Eng PJ, Hu MY, Chow P, Cai YQ, Shu J, Hemley RJ. X-ray-Induced Dissociation of H2O and Formation of an O2-H2 Alloy at High Pressure. Science 2006; 314:636-8. [PMID: 17068259 DOI: 10.1126/science.1132884] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
When subjected to high pressure and extensive x-radiation, water (H2O) molecules cleaved, forming O-O and H-H bonds. The oxygen (O) and hydrogen (H) framework in ice VII was converted into a molecular alloy of O2 and H2. X-ray diffraction, x-ray Raman scattering, and optical Raman spectroscopy demonstrated that this crystalline solid differs from previously known phases. It remained stable with respect to variations in pressure, temperature, and further x-ray and laser exposure, thus opening new possibilities for studying molecular interactions in the hydrogen-oxygen binary system.
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Affiliation(s)
- Wendy L Mao
- Los Alamos Neutron Science Center, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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23
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Shen G, Prakapenka VB, Eng PJ, Rivers ML, Sutton SR. Facilities for high-pressure research with the diamond anvil cell at GSECARS. J Synchrotron Radiat 2005; 12:642-9. [PMID: 16120989 DOI: 10.1107/s0909049505022442] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Accepted: 07/12/2005] [Indexed: 05/04/2023]
Abstract
An overview of facilities for high-pressure research with the diamond anvil cell (DAC) at the GeoSoilEnviroCARS (GSECARS) sector at the Advanced Photon Source (Argonne, Illinois) is presented. There are three operational experimental stations (13-ID-C, 13-ID-D and 13-BM-D) where DAC instrumentation is installed for various types of experiments at high pressure and extreme temperature conditions. A fourth station (13-BM-C) is under construction and will be operational in 2006. While most X-ray diffraction experiments have been undertaken with powder samples so far, there is a growing demand for single-crystal diffraction (SCD) at high pressure. As one of the principal components at GSECARS, SCD is currently under rapid development. Other relevant techniques have also been developed for obtaining complementary information from powder or single-crystal samples at high pressure. For example, an on-line Brillouin system is installed and operational at 13-BM-D for acoustic velocity and single-crystal elasticity determinations. In addition, various X-ray spectroscopy techniques (e.g. X-ray emission and X-ray Raman) are employed for measuring electronic and magnetic properties. Future developments are discussed with the DAC program at GSECARS.
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Affiliation(s)
- Guoyin Shen
- Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, USA.
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24
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Crot CA, Wu C, Schlossman ML, Trainor TP, Eng PJ, Hanley L. Determining the conformation of an adsorbed Br-PEG-peptide by long period X-ray standing wave fluorescence. Langmuir 2005; 21:7899-906. [PMID: 16089398 PMCID: PMC2583370 DOI: 10.1021/la0505115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Long-period X-ray standing wave fluorescence (XSW) and X-ray reflectivity techniques are employed to probe the conformation of a Br-poly(ethylene glycol) (PEG)-peptide adsorbate at the hydrated interface of a polystyrene substrate. The Br atom on this Br-PEG-peptide construct serves as a marker atom allowing determination by XSW of its position and distribution with respect to the adsorption surface with angstrom resolution. Adsorption occurs on native or ion-beam-modified polystyrene films that are spin-coated onto a Si substrate and display either nonpolar or polar surfaces, respectively. A compact, oriented monolayer of Br-PEG-peptide can be formed with the peptide end adsorbed onto the polar surface and the PEG end terminating with the Br tag extending into the aqueous phase. The 108-141 A distance of the Br atom from the polystyrene surface in this oriented monolayer is similar to the estimated approximately 150 A length of the extended Br-PEG-peptide. This Br-polystyrene distance depends on adsorption time and surface properties prior to adsorption. Incomplete multilayers form on the polar surface after sufficient adsorption time elapses. By contrast, adsorption onto the nonpolar surface is submonolayer, patchy, and highly disordered with an isotropic Br distribution. Overall, this combination of X-ray surface scattering techniques with a novel sample preparation strategy has several advantages as a real space probe of adsorbed or covalently bound biomolecules at the liquid-solid interface.
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Affiliation(s)
- Carrie A. Crot
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607-7061
| | - Chunping Wu
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607-7061
| | - Mark L. Schlossman
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607-7061
- Department of Physics, University of Illinois at Chicago, Chicago, IL 60607
| | - Thomas P. Trainor
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK 99775
| | - Peter J. Eng
- Center for Advanced Radiation Sources, The University of Chicago, Chicago, IL 60603
| | - Luke Hanley
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607-7061
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25
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Yoon TH, Trainor TP, Eng PJ, Bargar JR, Brown GE. Trace metal ion partitioning at polymer film-metal oxide interfaces: long-period X-ray standing wave study. Langmuir 2005; 21:4503-11. [PMID: 16032866 DOI: 10.1021/la047271y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The distributions of Pb(II) and As(V)O4(3-) ions in the interfacial region between thin poly(acrylic acid) (PAA) coatings and aalpha-A12O3(0001), alpha-Al2O3(1-102), and alpha-Fe2O3(0001) single-crystal substrates were studied using long-period X-ray standing wave fluorescent yield (XSW-FY) and X-ray reflectivity techniques. The PAA film serves as a simplified analogue of natural organic matter (NOM) coatings on mineral surfaces. Such coatings are often assumed to play an important role in the partitioning and speciation of trace heavy metals in soils and aquatic systems. On the alpha-Al2O3(1-102) surface, Pb(II) ions were found to preferentially bind to the PAA coating, even at sub-micromolar Pb(II) concentrations, and to partition increasingly onto the metal oxide surface as the Pb(II) concentration was increased ([Pb(II)] = 5 x 10(-8) to 2 x 10(-5) M, pH = 4.5; 0.01 M NaCl background electrolyte). This observation suggests that the binding sites in the PAA coating outcompete those on the alpha-Al2O3(1-102) surface for Pb(II) under these conditions. The As(V)O4(3-) oxoanion partitions preferentially to the L-Al2O3(1-102) surface for the As(V)O4(3-) concentrations examined (1 x 10(-7) to 5 x 10(-7) M, pH = 4.5; 0.01 M NaCl background electrolyte). Partitioning of Pb(II) (at 1 x 10(-7) M and pH 4.5) was also examined at PAA/alpha-Al2O3(0001), and PAA/alpha-Fe2O3(0001) interfaces using XSW-FY measurements. Our results show that the PAA coating was the dominant sink for Pb(II) in all three samples; however, the relative order of reactivity of these metal oxide surfaces with respect to Pb(II) sorption is alpha-Fe2O3(0001) > alpha-Al2O3(1-102) > alpha-Al2O3(0001). This order is consistent with that found in previous studies of the PAA-free surfaces. These XSW results strongly suggest that the characteristics of the organic film (i.e., binding affinity, type, and density of binding sites) as well as metal oxide substrate reactivity are key factors determining the distribution and speciation of Pb(II) and As(V)O4(3-) at organic film/metal oxide interfaces.
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Affiliation(s)
- Tae Hyun Yoon
- Surface & Aqueous Geochemistry Group, Department of Geological & Environmental Sciences, Stanford University, Stanford, California 94305-2115, USA.
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26
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Meng Y, Mao HK, Eng PJ, Trainor TP, Newville M, Hu MY, Kao C, Shu J, Hausermann D, Hemley RJ. The formation of sp3 bonding in compressed BN. Nat Mater 2004; 3:111-114. [PMID: 14743214 DOI: 10.1038/nmat1060] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2003] [Accepted: 12/19/2003] [Indexed: 05/24/2023]
Abstract
Attributed to their specific atomic bonding, the soft, graphite-like, hexagonal boron nitride (h-BN) and its superhard, diamond-like, cubic polymorph (c-BN) are important technological materials with a wide range of applications. At high pressure and temperature, h-BN can directly transform to a hexagonal close-packed polymorph (w-BN) that can be partially quenched after releasing pressure. Previous theoretical calculations and experimental measurements (primarily on quenched samples) provided substantial information on the transition, but left unsettled questions due to the lack of in situ characterization at high pressures. Using inelastic X-ray scattering to probe the boron and nitrogen near K-edge spectroscopy, here we report the first observation of the conversion process of boron and nitrogen sp(2)- and p-bonding to sp(3) and the directional nature of the sp(3) bonding. In combination with in situ X-ray diffraction probe, we have further clarified the structure transformation mechanism. The present archetypal example opens two enormous, element-specific, research areas on high-pressure bonding evolutions of boron and nitrogen; each of the two elements and their respective compounds have displayed a wealth of intriguing pressure-induced phenomena that result from bonding changes, including metallization, superconductivity, semiconductivity, polymerization and superhardness.
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Affiliation(s)
- Yue Meng
- HPCAT, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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27
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Abstract
Compressed under ambient temperature, graphite undergoes a transition at approximately 17 gigapascals. The near K-edge spectroscopy of carbon using synchrotron x-ray inelastic scattering reveals that half of the pi-bonds between graphite layers convert to sigma-bonds, whereas the other half remain as pi-bonds in the high-pressure form. The x-ray diffraction pattern of the high-pressure form is consistent with a distorted graphite structure in which bridging carbon atoms between graphite layers pair and form sigma-bonds, whereas the nonbridging carbon atoms remain unpaired with pi-bonds. The high-pressure form is superhard, capable of indenting cubic-diamond single crystals.
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Affiliation(s)
- Wendy L Mao
- Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA.
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28
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Trainor TP, Eng PJ, Robinson IK. Calculation of crystal truncation rod structure factors for arbitrary rational surface terminations. J Appl Crystallogr 2002. [DOI: 10.1107/s0021889802013985] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The technique of crystal truncation rod (CTR) diffraction is widely used for studying the structure of crystalline surfaces and interfaces. The theory and experimental details of the technique are well established; however, published methods for structure-factor calculations are typically based on a simple surface cell geometry. A method is presented for determining a surface coordinate system which results in a reciprocal lattice that is simply defined in terms of the surface termination. Based on this surface coordinate system, a general formalism for the calculation of CTR structure factors is re-derived, which may be easily applied to any surface that can be represented as a rational plane of a bulk crystal system.
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Abstract
The physical and chemical properties of the hydrated alpha-Al(2)O(3) (0001) surface are important for understanding the reactivity of natural and synthetic aluminum-containing oxides. The structure of this surface was determined in the presence of water vapor at 300 kelvin by crystal truncation rod diffraction at a third-generation synchrotron x-ray source. The fully hydrated surface is oxygen terminated, with a 53% contracted double Al layer directly below. The structure is an intermediate between alpha-Al(2)O(3) and gamma-Al(OH)(3), a fully hydroxylated form of alumina. A semiordered oxygen layer about 2.3 angstroms above the terminal oxygen layer is interpreted as adsorbed water. The clean alpha-Al(2)O(3) (0001) surface, in contrast, is Al terminated and significantly relaxed relative to the bulk structure. These differences explain the different reactivities of the clean and hydroxylated surfaces.
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Affiliation(s)
- PJ Eng
- Consortium for Advanced Radiation Sources, The University of Chicago, Chicago, IL 60637, USA. Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305-2115, USA. Stanford Synchrotron Radiation Laboratory, Sta
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Bennett PA, Lee MY, Yang P, Schuster R, Eng PJ, Robinson IK. Template structure at the silicon/amorphous-silicide interface. Phys Rev Lett 1995; 75:2726-2729. [PMID: 10059389 DOI: 10.1103/physrevlett.75.2726] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Reichert H, Eng PJ, Dosch H, Robinson IK. Thermodynamics of surface segregation profiles at Cu3Au(001) resolved by x-ray scattering. Phys Rev Lett 1995; 74:2006-2009. [PMID: 10057818 DOI: 10.1103/physrevlett.74.2006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Robinson IK, Eng PJ, Romainczyk C, Kern K. X-ray determination of the 1 x 3 reconstruction of Pt(110). Phys Rev B Condens Matter 1993; 47:10700-10705. [PMID: 10005187 DOI: 10.1103/physrevb.47.10700] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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