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Zhang Z, Ren J, Liang J, Xu X, Zhao L, Qiu H, Li H, Cao X. New Insight into the Natural Detoxification of Cr(VI) in Fe-Rich Surface Soil: Crucial Role of Photogenerated Silicate-Bound Fe(II). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:21370-21381. [PMID: 37946506 DOI: 10.1021/acs.est.3c05767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Photoexcitation of natural semiconductor Fe(III) minerals has been proven to generate Fe(II), but the photogeneration of Fe(II) in Fe-rich surface soil as well as its role in the redox biogeochemistry of Cr(VI) remains poorly understood. In this work, we confirmed the generation of Fe(II) in soil by solar irradiation and proposed a new mechanism for the natural reductive detoxification of Cr(VI) to Cr(III) in surface soil. The kinetic results showed that solar irradiation promoted the reduction of Cr(VI) in Fe-rich soils, while a negligible Cr(VI) reduction was observed in the dark. Fe(II), mainly in the form of silicate-bound Fe(II), was generated under solar irradiation and responsible for the reduction of Cr(VI) in soils, which was evidenced by sequential extraction, transmission electron microscopy with electron energy loss spectroscopy, and electron transfer calculation. Photogenerated silicate-bound Fe(II) resulted from the massive clay-iron (hydr)oxide associations, consisting of iron (hydr)oxides (e.g., hematite and goethite) and kaolinite. These associations could generate Fe(II) under solar irradiation either via intrinsic excitation to produce photoelectrons or via the ligand-to-metal charge transfer process after the formation of clay-iron (hydr)oxide-organic matter complexes, which was proven by photoluminescence spectroscopy and X-ray photoelectron spectroscopy. These findings highlight the important role of photogenerated Fe(II) in Cr(VI) reduction in surface soil, which advances a fundamental understanding of the natural detoxification of Cr(VI) as well as the redox biogeochemistry of Cr(VI) in soil.
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Affiliation(s)
- Zehong Zhang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jia Ren
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jun Liang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaoyun Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ling Zhao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hao Qiu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hao Li
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xinde Cao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Engineering Research Center of Solid Waste Treatment and Resource Recovery, Shanghai Jiao Tong University, Shanghai 200240, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
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2
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Qian Y, Scheinost AC, Grangeon S, Greneche JM, Hoving A, Bourhis E, Maubec N, Churakov SV, Fernandes MM. Oxidation State and Structure of Fe in Nontronite: From Oxidizing to Reducing Conditions. ACS EARTH & SPACE CHEMISTRY 2023; 7:1868-1881. [PMID: 37881367 PMCID: PMC10594735 DOI: 10.1021/acsearthspacechem.3c00136] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/30/2023] [Accepted: 08/30/2023] [Indexed: 10/27/2023]
Abstract
The redox reaction between natural Fe-containing clay minerals and its sorbates is a fundamental process controlling the cycles of many elements such as carbon, nutrients, redox-sensitive metals, and metalloids (e.g., Co, Mn, As, Se), and inorganic as well as organic pollutants in Earth's critical zone. While the structure of natural clay minerals under oxic conditions is well-known, less is known about their behavior under anoxic and reducing conditions, thereby impeding a full understanding of the mechanisms of clay-driven reduction and oxidation (redox) reactions especially under reducing conditions. Here we investigate the structure of a ferruginous natural clay smectite, nontronite, under different redox conditions, and compare several methods for the determination of iron redox states. Iron in nontronite was gradually reduced chemically with the citrate-bicarbonate-dithionite (CBD) method. 57Fe Mössbauer spectrometry, X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES) spectroscopy including its pre-edge, extended X-ray absorption fine structure (EXAFS) spectroscopy, and mediated electrochemical oxidation and reduction (MEO/MER) provided consistent Fe(II)/Fe(III) ratios. By combining X-ray diffraction (XRD) and transmission electron microscopy (TEM), we show that the long-range structure of nontronite at the highest obtained reduction degree of 44% Fe(II) is not different from that of fully oxidized nontronite except for a slight basal plane dissolution on the external surfaces. The short-range order probed by EXAFS spectroscopy suggests, however, an increasing structural disorder and Fe clustering with increasing reduction of structural Fe.
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Affiliation(s)
- Yanting Qian
- Laboratory
for Waste Management, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
- Institute
for Geological Sciences, University of Bern, CH-3012 Bern, Switzerland
| | - Andreas C. Scheinost
- The
Rossendorf Beamline at the European Synchrotron Radiation Facility
(ESRF), Avenue des Martyrs
71, 38043, Grenoble, France
- Helmholtz
Zentrum Dresden Rossendorf, Institute of
Resource Ecology, Bautzner
Landstrasse 400, 01328, Dresden, Germany
| | | | - Jean-Marc Greneche
- Institut
des Molécules et Matériaux du Mans IMMM UMR CNRS 6283,
Le Mans Université, 72085, Le Mans Cedex 9, France
| | - Alwina Hoving
- TNO
Geological Survey of The Netherlands,
P.O. Box 80015, 3508 TA Utrecht, The Netherlands
| | - Eric Bourhis
- Interfaces,
Confinement, Matériaux et Nanostructures (ICMN), CNRS/Université
d’Orléans, UMR 7374, 1b rue de la Férollerie, CS 40059, 45071 Orléans, France
| | | | - Sergey V. Churakov
- Laboratory
for Waste Management, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
- Institute
for Geological Sciences, University of Bern, CH-3012 Bern, Switzerland
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Qian A, Lu Y, Zhang Y, Yu C, Zhang P, Liao W, Yao Y, Zheng Y, Tong M, Yuan S. Mechanistic Insight into Electron Transfer from Fe(II)-Bearing Clay Minerals to Fe (Hydr)oxides. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:8015-8025. [PMID: 37204932 DOI: 10.1021/acs.est.3c01250] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Electron transfer (ET) is the essence of most biogeochemical processes related to element cycling and contaminant attenuation, whereas ET between different minerals and the controlling mechanism remain elusive. Here, we used surface-associated Fe(II) as a proxy to explore ET between reduced nontronite NAu-2 (rNAu-2) and Fe (hydr)oxides in their coexisting systems. Results showed that ET could occur from rNAu-2 to ferrihydrite but not to goethite, and the ET amount was determined by the number of reactive sites and the reduction potential difference between rNAu-2 and ferrihydrite. ET proceeded mainly through the mineral-mineral interface, with a negligible contribution of dissolved Fe2+/Fe3+. Control experiments by adding K+ and increasing salinity together with characterizations by X-ray diffraction, scanning electron microscopy/energy-dispersive spectrometry, and atomic force microscopy suggested that ferrihydrite nanoparticles inserted the interlayer space in rNAu-2 where structural Fe(II) in rNAu-2 transferred electrons mainly through the basal plane to ferrihydrite. This study implicates the occurrence of ET between different redox-active minerals through the mineral-mineral interface. As minerals at different reduction potentials often coexist in soils/sediments, the mineral-mineral ET may play an important role in subsurface biogeochemical processes.
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Affiliation(s)
- Ao Qian
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
| | - Yuxi Lu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
| | - Yanting Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
| | - Chenglong Yu
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
| | - Peng Zhang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
| | - Wenjuan Liao
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, P. R. China
| | - Yao Yao
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
| | - Yunsong Zheng
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
| | - Man Tong
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
| | - Songhu Yuan
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
- Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, School of Environmental Studies, China University of Geosciences, No. 68 Jincheng Street, East Lake High-Tech Development Zone, Wuhan 430078, P. R. China
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4
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Fan Q, Wang L, Fu Y, Li Q, Liu Y, Wang Z, Zhu H. Iron redox cycling in layered clay minerals and its impact on contaminant dynamics: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 855:159003. [PMID: 36155041 DOI: 10.1016/j.scitotenv.2022.159003] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/30/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
A majority of clay minerals contain Fe, and the redox cycling of Fe(III)/Fe(II) in clay minerals has been extensively studied as it may fuel the biogeochemical cycles of nutrients and govern the mobility, toxicity and bioavailability of a number of environmental contaminants. There are three types of Fe in clay minerals, including structural Fe sandwiched in the lattice of clays, Fe species in interlayer space and adsorbed on the external surface of clays. They exhibit distinct reactivity towards contaminants due to their differences in redox properties and accessibility to contaminant species. In natural environments, microbially driven Fe(III)/Fe(II) redox cycling in clay minerals is thought to be important, whereas reductants (e.g., dithionite and Fe(II)) or oxidants (e.g., peroxygens) are capable of enhancing the rates and extents of redox dynamics in engineered systems. Fe(III)-containing clay minerals can directly react with oxidizable pollutants (e.g., phenols and polycyclic aromatic hydrocarbons (PAHs)), whereas structural Fe(II) is able to react with reducible pollutants, such as nitrate, nitroaromatic compounds, chlorinated aliphatic compounds. Also structural Fe(II) can transfer electrons to oxygen (O2), peroxymonosulfate (PMS), or hydrogen peroxide (H2O2), yielding reactive radicals that can promote the oxidative transformation of contaminants. This review summarizes the recent discoveries on redox reactivity of Fe in clay minerals and its links to fates of environmental contaminants. The biological and chemical reduction mechanisms of Fe(III)-clay minerals, as well as the interaction mechanism between Fe(III) or Fe(II)-containing clay minerals and contaminants are elaborated. Some knowledge gaps are identified for better understanding and modelling of clay-associated contaminant behavior and effective design of remediation solutions.
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Affiliation(s)
- Qingya Fan
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Lingli Wang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Yu Fu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Qingchao Li
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Yunjiao Liu
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Zhaohui Wang
- Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China; State Key Laboratory of Mineral Processing, Beijing 102628, China; Shanghai Engineering Research Center of Biotransformation of Organic Solid Waste, Shanghai 200241, China; Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan Area, Ministry of Natural Resources, 3663 N. Zhongshan Road, Shanghai 200062, China.
| | - Huaiyong Zhu
- School of Chemistry and Physics, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD 4001, Australia
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5
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Tosca NJ, Agee CB, Cockell CS, Glavin DP, Hutzler A, Marty B, McCubbin FM, Regberg AB, Velbel MA, Kminek G, Meyer MA, Beaty DW, Carrier BL, Haltigin T, Hays LE, Busemann H, Cavalazzi B, Debaille V, Grady MM, Hauber E, Pratt LM, Smith AL, Smith CL, Summons RE, Swindle TD, Tait KT, Udry A, Usui T, Wadhwa M, Westall F, Zorzano MP. Time-Sensitive Aspects of Mars Sample Return (MSR) Science. ASTROBIOLOGY 2022; 22:S81-S111. [PMID: 34904889 DOI: 10.1089/ast.2021.0115] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Samples returned from Mars would be placed under quarantine at a Sample Receiving Facility (SRF) until they are considered safe to release to other laboratories for further study. The process of determining whether samples are safe for release, which may involve detailed analysis and/or sterilization, is expected to take several months. However, the process of breaking the sample tube seal and extracting the headspace gas will perturb local equilibrium conditions between gas and rock and set in motion irreversible processes that proceed as a function of time. Unless these time-sensitive processes are understood, planned for, and/or monitored during the quarantine period, scientific information expected from further analysis may be lost forever. At least four processes underpin the time-sensitivity of Mars returned sample science: (1) degradation of organic material of potential biological origin, (2) modification of sample headspace gas composition, (3) mineral-volatile exchange, and (4) oxidation/reduction of redox-sensitive materials. Available constraints on the timescales associated with these processes supports the conclusion that an SRF must have the capability to characterize attributes such as sample tube headspace gas composition, organic material of potential biological origin, as well as volatiles and their solid-phase hosts. Because most time-sensitive investigations are also sensitive to sterilization, these must be completed inside the SRF and on timescales of several months or less. To that end, we detail recommendations for how sample preparation and analysis could complete these investigations as efficiently as possible within an SRF. Finally, because constraints on characteristic timescales that define time-sensitivity for some processes are uncertain, future work should focus on: (1) quantifying the timescales of volatile exchange for core material physically and mineralogically similar to samples expected to be returned from Mars, and (2) identifying and developing stabilization or temporary storage strategies that mitigate volatile exchange until analysis can be completed. Executive Summary Any samples returned from Mars would be placed under quarantine at a Sample Receiving Facility (SRF) until it can be determined that they are safe to release to other laboratories for further study. The process of determining whether samples are safe for release, which may involve detailed analysis and/or sterilization, is expected to take several months. However, the process of breaking the sample tube seal and extracting the headspace gas would perturb local equilibrium conditions between gas and rock and set in motion irreversible processes that proceed as a function of time. Unless these processes are understood, planned for, and/or monitored during the quarantine period, scientific information expected from further analysis may be lost forever. Specialist members of the Mars Sample Return Planning Group Phase 2 (MSPG-2), referred to here as the Time-Sensitive Focus Group, have identified four processes that underpin the time-sensitivity of Mars returned sample science: (1) degradation of organic material of potential biological origin, (2) modification of sample headspace gas composition, (3) mineral-volatile exchange, and (4) oxidation/reduction of redox-sensitive materials (Figure 2). Consideration of the timescales and the degree to which these processes jeopardize scientific investigations of returned samples supports the conclusion that an SRF must have the capability to characterize: (1) sample tube headspace gas composition, (2) organic material of potential biological origin, (3) volatiles bound to or within minerals, and (4) minerals or other solids that host volatiles (Table 4). Most of the investigations classified as time-sensitive in this report are also sensitive to sterilization by either heat treatment and/or gamma irradiation (Velbel et al., 2022). Therefore, these investigations must be completed inside biocontainment and on timescales that minimize the irrecoverable loss of scientific information (i.e., several months or less; Section 5). To that end, the Time-Sensitive Focus Group has outlined a number of specific recommendations for sample preparation and instrumentation in order to complete these investigations as efficiently as possible within an SRF (Table 5). Constraints on the characteristic timescales that define time-sensitivity for different processes can range from relatively coarse to uncertain (Section 4). Thus, future work should focus on: (1) quantifying the timescales of volatile exchange for variably lithified core material physically and mineralogically similar to samples expected to be returned from Mars, and (2) identifying and developing stabilization strategies or temporary storage strategies that mitigate volatile exchange until analysis can be completed. List of Findings FINDING T-1: Aqueous phases, and oxidants liberated by exposure of the sample to aqueous phases, mediate and accelerate the degradation of critically important but sensitive organic compounds such as DNA. FINDING T-2: Warming samples increases reaction rates and destroys compounds making biological studies much more time-sensitive. MAJOR FINDING T-3: Given the potential for rapid degradation of biomolecules, (especially in the presence of aqueous phases and/or reactive O-containing compounds) Sample Safety Assessment Protocol (SSAP) and parallel biological analysis are time sensitive and must be carried out as soon as possible. FINDING T-4: If molecules or whole cells from either extant or extinct organisms have persisted under present-day martian conditions in the samples, then it follows that preserving sample aliquots under those same conditions (i.e., 6 mbar total pressure in a dominantly CO2 atmosphere and at an average temperature of -80°C) in a small isolation chamber is likely to allow for their continued persistence. FINDING T-5: Volatile compounds (e.g., HCN and formaldehyde) have been lost from Solar System materials stored under standard curation conditions. FINDING T-6: Reactive O-containing species have been identified in situ at the martian surface and so may be present in rock or regolith samples returned from Mars. These species rapidly degrade organic molecules and react more rapidly as temperature and humidity increase. FINDING T-7: Because the sample tubes would not be closed with perfect seals and because, after arrival on Earth, there will be a large pressure gradient across that seal such that the probability of contamination of the tube interiors by terrestrial gases increases with time, the as-received sample tubes are considered a poor choice for long-term gas sample storage. This is an important element of time sensitivity. MAJOR FINDING T-8: To determine how volatiles may have been exchanged with headspace gas during transit to Earth, the composition of martian atmosphere (in a separately sealed reservoir and/or extracted from the witness tubes), sample headspace gas composition, temperature/time history of the samples, and mineral composition (including mineral-bound volatiles) must all be quantified. When the sample tube seal is breached, mineral-bound volatile loss to the curation atmosphere jeopardizes robust determination of volatile exchange history between mineral and headspace. FINDING T-9: Previous experiments with mineral powders show that sulfate minerals are susceptible to H2O loss over timescales of hours to days. In addition to volatile loss, these processes are accompanied by mineralogical transformation. Thus, investigations targeting these minerals should be considered time-sensitive. FINDING T-10: Sulfate minerals may be stabilized by storage under fixed relative-humidity conditions, but only if the identity of the sulfate phase(s) is known a priori. In addition, other methods such as freezing may also stabilize these minerals against volatile loss. FINDING T-11: Hydrous perchlorate salts are likely to undergo phase transitions and volatile exchange with ambient surroundings in hours to days under temperature and relative humidity ranges typical of laboratory environments. However, the exact timescale over which these processes occur is likely a function of grain size, lithification, and/or cementation. FINDING T-12: Nanocrystalline or X-ray amorphous materials are typically stabilized by high proportions of surface adsorbed H2O. Because this surface adsorbed H2O is weakly bound compared to bulk materials, nanocrystalline materials are likely to undergo irreversible ripening reactions in response to volatile loss, which in turn results in decreases in specific surface area and increases in crystallinity. These reactions are expected to occur over the timescale of weeks to months under curation conditions. Therefore, the crystallinity and specific surface area of nanocrystalline materials should be characterized and monitored within a few months of opening the sample tubes. These are considered time-sensitive measurements that must be made as soon as possible. FINDING T-13: Volcanic and impact glasses, as well as opal-CT, are metastable in air and susceptible to alteration and volatile exchange with other solid phases and ambient headspace. However, available constraints indicate that these reactions are expected to proceed slowly under typical laboratory conditions (i.e., several years) and so analyses targeting these materials are not considered time sensitive. FINDING T-14: Surface adsorbed and interlayer-bound H2O in clay minerals is susceptible to exchange with ambient surroundings at timescales of hours to days, although the timescale may be modified depending on the degree of lithification or cementation. Even though structural properties of clay minerals remain unaffected during this process (with the exception of the interlayer spacing), investigations targeting H2O or other volatiles bound on or within clay minerals should be considered time sensitive upon opening the sample tube. FINDING T-15: Hydrated Mg-carbonates are susceptible to volatile loss and recrystallization and transformation over timespans of months or longer, though this timescale may be modified by the degree of lithification and cementation. Investigations targeting hydrated carbonate minerals (either the volatiles they host or their bulk mineralogical properties) should be considered time sensitive upon opening the sample tube. MAJOR FINDING T-16: Current understanding of mineral-volatile exchange rates and processes is largely derived from monomineralic experiments and systems with high surface area; lithified sedimentary rocks (accounting for some, but not all, of the samples in the cache) will behave differently in this regard and are likely to be associated with longer time constants controlled in part by grain boundary diffusion. Although insufficient information is available to quantify this at the present time, the timescale of mineral-volatile exchange in lithified samples is likely to overlap with the sample processing and curation workflow (i.e., 1-10 months; Table 4). This underscores the need to prioritize measurements targeting mineral-hosted volatiles within biocontainment. FINDING T-17: The liberation of reactive O-species through sample treatment or processing involving H2O (e.g., rinsing, solvent extraction, particle size separation in aqueous solution, or other chemical extraction or preparation protocols) is likely to result in oxidation of some component of redox-sensitive materials in a matter of hours. The presence of reactive O-species should be examined before sample processing steps that seek to preserve or target redox-sensitive minerals. Electron paramagnetic resonance spectroscopy (EPR) is one example of an effective analytical method capable of detecting and characterizing the presence of reactive O-species. FINDING T-18: Environments that maintain anoxia under inert gas containing <<1 ppm O2 are likely to stabilize redox-sensitive minerals over timescales of several years. MAJOR FINDING T-19: MSR investigations targeting organic macromolecular or cellular material, mineral-bound volatile compounds, redox sensitive minerals, and/or hydrous carbonate minerals can become compromised at the timescale of weeks (after opening the sample tube), and scientific information may be completely lost within a time timescale of a few months. Because current considerations indicate that completion of SSAP, sample sterilization, and distribution to investigator laboratories cannot be completed in this time, these investigations must be completed within the Sample Receiving Facility as soon as possible.
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Affiliation(s)
- Nicholas J Tosca
- University of Cambridge, Department of Earth Sciences, Cambridge, UK
| | - Carl B Agee
- University of New Mexico, Institute of Meteoritics, Albuquerque, New Mexico, USA
| | - Charles S Cockell
- University of Edinburgh, Centre for Astrobiology, School of Physics and Astronomy, Edinburgh, UK
| | - Daniel P Glavin
- NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, Maryland, USA
| | | | | | - Francis M McCubbin
- NASA Johnson Space Center, Astromaterials Research and Exploration Science Division, Houston, Texas, USA
| | - Aaron B Regberg
- NASA Johnson Space Center, Astromaterials Research and Exploration Science Division, Houston, Texas, USA
| | - Michael A Velbel
- Michigan State University, Earth and Environmental Sciences, East Lansing, Michigan, USA
- Smithsonian Institution, Department of Mineral Sciences, National Museum of Natural History, Washington, DC, USA
| | | | - Michael A Meyer
- NASA Headquarters, Mars Sample Return Program, Washington, DC, USA
| | - David W Beaty
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Brandi L Carrier
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | | | - Lindsay E Hays
- NASA Headquarters, Mars Sample Return Program, Washington, DC, USA
| | - Henner Busemann
- ETH Zürich, Institute of Geochemistry and Petrology, Zürich, Switzerland
| | - Barbara Cavalazzi
- Università di Bologna, Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Bologna, Italy
| | | | | | - Ernst Hauber
- German Aerospace Center (DLR), Institute of Planetary Research, Berlin, Germany
| | - Lisa M Pratt
- Indiana University Bloomington, Earth and Atmospheric Sciences, Bloomington, Indiana, USA
| | - Alvin L Smith
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Caroline L Smith
- Natural History Museum, Department of Earth Sciences, London, UK
- University of Glasgow, School of Geographical and Earth Sciences, Glasgow, UK
| | - Roger E Summons
- Massachusetts Institute of Technology, Earth, Atmospheric and Planetary Sciences, Cambridge, Massachusetts, USA
| | - Timothy D Swindle
- University of Arizona, Lunar and Planetary Laboratory, Tucson, Arizona, USA
| | - Kimberly T Tait
- Royal Ontario Museum, Department of Natural History, Toronto, Ontario, Canada
| | - Arya Udry
- University of Nevada Las Vegas, Las Vegas, Nevada, USA
| | - Tomohiro Usui
- Japan Aerospace Exploration Agency (JAXA), Institute of Space and Astronautical Science (ISAS), Chofu, Tokyo, Japan
| | - Meenakshi Wadhwa
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
- Arizona State University, Tempe, Arizona, USA
| | - Frances Westall
- Centre National de la Recherche Scientifique (CNRS), Centre de Biophysique Moléculaire, Orléans, France
| | - Maria-Paz Zorzano
- Centro de Astrobiologia (CSIC-INTA), Torrejon de Ardoz, Spain
- University of Aberdeen, Department of Planetary Sciences, School of Geosciences, King's College, Aberdeen, UK
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6
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Zhao Z, Yuan Q, Meng Y, Luan F. Oxidation of bioreduced iron-bearing clay mineral triggers arsenic immobilization. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:44874-44882. [PMID: 35138538 DOI: 10.1007/s11356-022-19028-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 01/30/2022] [Indexed: 06/14/2023]
Abstract
Iron-bearing clay minerals and arsenic commonly coexist in soils and sediments. Redox oscillation from anoxic to oxic conditions can result in structural Fe(II) oxidation in clay minerals. However, the role of structural Fe(II) oxidation in clay minerals on arsenic immobilization is still unclear. In this study, we found that oxidation of structural Fe(II) in bioreduced clay mineral nontronite (NAu-2) triggered As(III) adsorption onto NAu-2. As(III) was adsorbed onto NAu-2 through ligand exchange with hydroxyl groups which were generated by the oxidation of structural Fe(II) in NAu-2. In addition, oxidation of structural Fe(II) led to the oxidation of As(III) to As(V), which further enhanced the adsorption of dissolved As(III) on NAu-2. Therefore, the adsorption capacity of As(III) onto oxidized NAu-2 was 1.6 times higher than that of native NAu-2. Oxidation of structural Fe(II) was a two-stage process that proceeded from exterior sites to interior sites, and the immobilization and oxidation of As(III) occurred predominantly at the rapid exterior structural Fe(II) oxidation stage. Our findings highlight that the oxidation of structural Fe(II) in iron-bearing clay minerals may play an important role in arsenic immobilization and transformation in the subsurface environment.
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Affiliation(s)
- Ziwang Zhao
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, People's Republic of China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Qingke Yuan
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, People's Republic of China
| | - Ying Meng
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, People's Republic of China
| | - Fubo Luan
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, People's Republic of China.
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
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7
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Huang J, Jones A, Waite TD, Chen Y, Huang X, Rosso KM, Kappler A, Mansor M, Tratnyek PG, Zhang H. Fe(II) Redox Chemistry in the Environment. Chem Rev 2021; 121:8161-8233. [PMID: 34143612 DOI: 10.1021/acs.chemrev.0c01286] [Citation(s) in RCA: 177] [Impact Index Per Article: 59.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Iron (Fe) is the fourth most abundant element in the earth's crust and plays important roles in both biological and chemical processes. The redox reactivity of various Fe(II) forms has gained increasing attention over recent decades in the areas of (bio) geochemistry, environmental chemistry and engineering, and material sciences. The goal of this paper is to review these recent advances and the current state of knowledge of Fe(II) redox chemistry in the environment. Specifically, this comprehensive review focuses on the redox reactivity of four types of Fe(II) species including aqueous Fe(II), Fe(II) complexed with ligands, minerals bearing structural Fe(II), and sorbed Fe(II) on mineral oxide surfaces. The formation pathways, factors governing the reactivity, insights into potential mechanisms, reactivity comparison, and characterization techniques are discussed with reference to the most recent breakthroughs in this field where possible. We also cover the roles of these Fe(II) species in environmental applications of zerovalent iron, microbial processes, biogeochemical cycling of carbon and nutrients, and their abiotic oxidation related processes in natural and engineered systems.
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Affiliation(s)
- Jianzhi Huang
- Department of Civil and Environmental Engineering, Case Western Reserve University, 2104 Adelbert Road, Cleveland, Ohio 44106, United States
| | - Adele Jones
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - T David Waite
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Yiling Chen
- Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiaopeng Huang
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Kevin M Rosso
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Andreas Kappler
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany
| | - Muammar Mansor
- Geomicrobiology, Center for Applied Geosciences, University of Tuebingen, 72076 Tuebingen, Germany
| | - Paul G Tratnyek
- School of Public Health, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Huichun Zhang
- Department of Civil and Environmental Engineering, Case Western Reserve University, 2104 Adelbert Road, Cleveland, Ohio 44106, United States
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8
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Kéri A, Dähn R, Krack M, Churakov SV. Characterization of Structural Iron in Smectites - An Ab Initio Based X-ray Absorption Spectroscopy Study. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:6877-6886. [PMID: 31120750 DOI: 10.1021/acs.est.8b06952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Fe-bearing clay minerals are abundant in argillaceous rocks as their redox-active structural iron may control the sorption mechanism of redox sensitive elements on the surface of clay minerals. The extent and efficiency of the redox reactions depend on the oxidation state (Fe2+/Fe3+ ratio) and structural distribution of the substituting cations in the TOT-layer of clay minerals. Even smectites with similar structure originating from different locations might have a distinct arrangement of isomorphic substitutions (e.g., individual iron or Fe-Fe pairs). In this study, the proportion of different iron distribution in Milos-, Wyoming-, and Texas-montmorillonite was determined by combining X-ray absorption spectroscopy (XAS) with ab initio calculations. The relaxed atomic structures of the smectite models with different arrangement of individual Fe atoms and Fe-Fe/Fe-Mg clusters served as the basis for the calculations of the XAS spectra. The combination of simulation results and measured Fe K-edge XAS spectra of Wyoming-, Milos- and Texas-montmorillonites suggested that iron is present as Fe3+ in the octahedral sheet. Fe3+ in Texas-montmorillonite has a tendency to form clusters, while no definitive statement about clustering or avoidance of Fe-Fe and Fe-Mg pairs can be made for Milos- and Wyoming-montmorillonite.
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Affiliation(s)
- Annamária Kéri
- Laboratory for Waste Management , Paul Scherrer Institute , CH-5232 Villigen PSI, Switzerland
- Institute for Geological Sciences , University of Bern , CH-3012 Bern , Switzerland
| | - Rainer Dähn
- Laboratory for Waste Management , Paul Scherrer Institute , CH-5232 Villigen PSI, Switzerland
| | - Matthias Krack
- Laboratory for Scientific Computing and Modelling , Paul Scherrer Institute , CH-5232 Villigen PSI, Switzerland
| | - Sergey V Churakov
- Laboratory for Waste Management , Paul Scherrer Institute , CH-5232 Villigen PSI, Switzerland
- Institute for Geological Sciences , University of Bern , CH-3012 Bern , Switzerland
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9
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Jones AM, Murphy CA, Waite TD, Collins RN. Fe(II) Interactions with Smectites: Temporal Changes in Redox Reactivity and the Formation of Green Rust. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:12573-12582. [PMID: 28976182 DOI: 10.1021/acs.est.7b01793] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this study, temporal changes in the redox properties of three 0.5 g/L smectite suspensions were investigated-a montmorillonite (MAu-1) and two nontronites (NAu-1 and NAu-2) in the presence of 1 mM aqueous Fe(II) at pH 7.8. X-ray absorption spectroscopy revealed that the amount of Fe(II) added quantitatively transformed into chloride-green rust (Cl-GR) within 5 min and persisted over 18 days. Over the same time, the reduction potential of all three suspensions increased by 50 to 150 mV to equilibrate at approximately -100 mV vs SHE. The reduction of a model organic contaminant, 4-chloronitrobenzene (4-CINB), also became increasingly slower over time with virtually no 4-CINB reduction being observed after 18 days. There was a strong correlation between reduction potential and the quantity of 4-ClNB reduced by MAu-1, although other factors were likely involved in the decreased redox reactivity observed in the nontronites. It is hypothesized that the temporal increase in reduction potential results from clay mineral dissolution resulting in increased Fe(III) contents in the Cl-GR. These results demonstrate that long-term studies are recommended to accurately predict contaminant management strategies.
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Affiliation(s)
- Adele M Jones
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Cassandra A Murphy
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - T David Waite
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Richard N Collins
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia
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10
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Ilgen AG, Kruichak JN, Artyushkova K, Newville MG, Sun C. Redox Transformations of As and Se at the Surfaces of Natural and Synthetic Ferric Nontronites: Role of Structural and Adsorbed Fe(II). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:11105-11114. [PMID: 28850224 DOI: 10.1021/acs.est.7b03058] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Adsorption and redox transformations on clay mineral surfaces are prevalent in surface environments. We examined the redox reactivity of iron Fe(II)/Fe(III) associated with natural and synthetic ferric nontronites. Specifically, we assessed how Fe(II) residing in the octahedral sheets, or Fe(II) adsorbed at the edge sites alters redox activity of nontronites. To probe the redox activity we used arsenic (As) and selenium (Se). Activation of both synthetic and natural ferric nontronites was observed following the introduction of Fe(II) into predominantly-Fe(III) octahedral sheets or through the adsorption of Fe(II) onto the mineral surface. The oxidation of As(III) to As(V) was observed via catalytic (oxic conditions) and, to a lesser degree, via direct (anoxic conditions) pathways. We provide experimental evidence for electron transfer from As(III) to Fe(III) at the natural and synthetic nontronite surfaces, and illustrate that only a fraction of structural Fe(III) is accessible for redox transformations. We show that As adsorbed onto natural and synthetic nontronites forms identical adsorption complexes, namely inner-sphere binuclear bidentate. We show that the formation of an inner-sphere adsorption complex may be a necessary step for the redox transformation via catalytic or direct oxidation pathways.
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Affiliation(s)
- Anastasia G Ilgen
- Sandia National Laboratories , Geochemistry Department, 1515 Eubank Boulevard Southeast Mailstop 0754, Albuquerque, New Mexico 87185-0754, United States
| | - Jessica N Kruichak
- Sandia National Laboratories , Geochemistry Department, 1515 Eubank Boulevard Southeast Mailstop 0754, Albuquerque, New Mexico 87185-0754, United States
| | - Kateryna Artyushkova
- University of New Mexico , Advanced Materials Laboratory, 1001 University Boulevard Southeast, Albuquerque, New Mexico 87106, United States
| | - Matt G Newville
- X-ray Science Division, Argonne National Laboratory , Building 435/E006, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
| | - Chengjun Sun
- X-ray Science Division, Argonne National Laboratory , Building 435/E006, 9700 South Cass Avenue, Argonne, Illinois 60439, United States
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11
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Shaikhutdinov S, Freund HJ. Ultra-thin silicate films on metals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:443001. [PMID: 26459605 DOI: 10.1088/0953-8984/27/44/443001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Silica is one of the key materials in many modern technological applications. 'Surface science' approach for understanding surface chemistry on silica-based materials, on the one hand, and further miniaturization of new generation electronic devices, on the other, all these face the necessity of rational design of the ultrathin silica films on electrically conductive substrates. The review updates recent studies in this field. Despite the structural complexity and diversity of silica, substantial progress has recently been achieved in understanding of the atomic structure of truly 2D silicates.
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Affiliation(s)
- Shamil Shaikhutdinov
- Abteilung Chemische Physik, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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12
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Sander M, Hofstetter TB, Gorski CA. Electrochemical analyses of redox-active iron minerals: a review of nonmediated and mediated approaches. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:5862-78. [PMID: 25856208 DOI: 10.1021/acs.est.5b00006] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Redox-active minerals are ubiquitous in the environment and are involved in numerous electron transfer reactions that significantly affect biogeochemical processes and cycles as well as pollutant dynamics. As a consequence, research in different scientific disciplines is devoted to elucidating the redox properties and reactivities of minerals. This review focuses on the characterization of mineral redox properties using electrochemical approaches from an applied (bio)geochemical and environmental analytical chemistry perspective. Establishing redox equilibria between the minerals and working electrodes is a major challenge in electrochemical measurements, which we discuss in an overview of traditional electrochemical techniques. These issues can be overcome with mediated electrochemical analyses in which dissolved redox mediators are used to increase the rate of electron transfer and to facilitate redox equilibration between working electrodes and minerals in both amperometric and potentiometric measurements. Using experimental data on an iron-bearing clay mineral, we illustrate how mediated electrochemical analyses can be employed to derive important thermodynamic and kinetic data on electron transfer to and from structural iron. We summarize anticipated methodological advancements that will further contribute to advance an improved understanding of electron transfer to and from minerals in environmentally relevant redox processes.
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Affiliation(s)
- Michael Sander
- †Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Environmental Chemistry, Swiss Federal Institute of Technology (ETH), Universitätstrasse 16, 8092 Zurich, Switzerland
| | - Thomas B Hofstetter
- ‡Environmental Chemistry, Swiss Federal Institute of Aquatic Science and Technology (Eawag), Ueberlandstrasse 133,8600 Duebendorf, Switzerland
| | - Christopher A Gorski
- §Civil and Environmental Engineering, The Pennsylvania State University, 212 Sackett Building, University Park, Pennsylvania 16802-1408, United States
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13
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Włodarczyk R, Sauer J, Yu X, Boscoboinik JA, Yang B, Shaikhutdinov S, Freund HJ. Atomic Structure of an Ultrathin Fe-Silicate Film Grown on a Metal: A Monolayer of Clay? J Am Chem Soc 2013; 135:19222-8. [DOI: 10.1021/ja408772p] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Radosław Włodarczyk
- Institute
of Chemistry, Humboldt-Universität zu Berlin, Unter den
Linden 6, 10099 Berlin, Germany
| | - Joachim Sauer
- Institute
of Chemistry, Humboldt-Universität zu Berlin, Unter den
Linden 6, 10099 Berlin, Germany
| | - Xin Yu
- Chemical
Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Jorge Anibal Boscoboinik
- Chemical
Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Bing Yang
- Chemical
Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Shamil Shaikhutdinov
- Chemical
Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
| | - Hans-Joachim Freund
- Chemical
Physics Department, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany
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14
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The Use of Chemical Probes for the Characterization of the Predominant Abiotic Reductants in Anaerobic Sediments. ACTA ACUST UNITED AC 2011. [DOI: 10.1021/bk-2011-1071.ch024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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