Hostname: page-component-cb9f654ff-5kfdg Total loading time: 0 Render date: 2025-08-31T18:02:45.928Z Has data issue: false hasContentIssue false

Partitioning of Fe(II) in reduced nontronite (NAu-2) to reactive sites: Reactivity in terms of Tc(VII) reduction

Published online by Cambridge University Press:  01 January 2024

Deb P. Jaisi
Affiliation:
Department of Geology, Miami University, Oxford, OH 45056, USA Department of Geology and Geophysics, Yale University, PO Box 20820, New Haven, CT 06520, USA
Hailiang Dong*
Affiliation:
Department of Geology, Miami University, Oxford, OH 45056, USA
John P. Morton
Affiliation:
Department of Geology, Miami University, Oxford, OH 45056, USA
*
* E-mail address of corresponding author: dongh@muohio.edu

Abstract

Clay minerals impart important chemical properties to soils, in part, by virtue of changes in the redox state of Fe in their crystal structures. Therefore, measurement of Fe(III)/Fe(II) and partitioning of Fe(II) in different reactive sites in clay minerals (during biological and chemical Fe(III) reduction) is essential to understand their role and their relative reactivity in terms of reduction and immobilization of heavy metal contaminants such as technetium. This study had three objectives: (1) to understand the degree of dissolution of nontronite (Fe-rich smectite) as a result of chemical and biological reduction of Fe(III) in the structure; (2) to quantify partitioning of chemically and biologically produced Fe(II) into different reactive sites in reduced nontronite, including aqueous Fe2+, ammonium chloride-extractable Fe(II) (mainly from the ion-exchangeable sites, denoted as Fe(II)NH4Cl${\rm{Fe}}{\left( {{\rm{II}}} \right)_{{\rm{N}}{{\rm{H}}_4}{\rm{Cl}}}}$), sodium acetate-extractable Fe(II) (mainly from the surface complexation sites, denoted as Fe(II)acetate), and structural Fe(II) (denoted as Fe(II)str); and (3) to evaluate the reactivity of these Fe(II) species in terms of Tc(VII) reduction. Chemical and biological reduction of Fe(III) in nontronite (NAu-2) was performed, and reduced nontronite samples with different extents of Fe(III) reduction (1.2–71%) were prepared. The extent of reductive dissolution was measured as a function of the extent of Fe(III) reduction. Our results demonstrated that chemically and biologically produced Fe(II) in NAu-2 may be accommodated in the NAu-2 structure if the extent of Fe(III) reduction is small (< ∼30%). When the extent of reduction was >∼30%, dissolution of nontronite occurred with a corresponding decrease in crystallinity of residual nontronite. The Fe(II) produced was available for partitioning into four species: Fe(ab)2+${\rm{Fe}}_{\left( {{\rm{ab}}} \right)}^{2 + }$, Fe(II)acetate, Fe(II)NH4Cl${\rm{Fe}}{\left( {{\rm{II}}} \right)_{{\rm{N}}{{\rm{H}}_4}{\rm{Cl}}}}$, and Fe(II)str. The increase in Fe(II)acetate during the early stages of Fe(III) reduction indicated that the Fe(II) released had the greatest affinity for the surface-complexation sites, but this site had a limited capacity (∼60 µmol of Fe(II)/g of NAu-2). The subsequent increase in Fe(II)NH4Cl${\rm{Fe}}{\left( {{\rm{II}}} \right)_{{\rm{N}}{{\rm{H}}_4}{\rm{Cl}}}}$ indicated that the released Fe(II) partitioned into the exchangeable sites once the amount of Fe at the surface-complexation sites reached half of its maximum site capacity. The fraction of Fe(II)str decreased concomitantly, as a result of Fe(II) release from the NAu-2 structure, from 100% when the extent of Fe(III) reduction was <30% to nearly 65% when the extent of Fe(III) reduction reached 71%. The Fe(II)acetate and Fe(II)str exhibited greater reactivity in terms of Tc(VII) reduction than the Fe(II)NH4Cl${\rm{Fe}}{\left( {{\rm{II}}} \right)_{{\rm{N}}{{\rm{H}}_4}{\rm{Cl}}}}$. Clearly, the surface-complexed and structural Fe(II) are the desirable species when reduced clay minerals are used to reduce and immobilize soluble heavy metals in contaminated groundwater and soils. These results have important implications for understanding microbe—clay mineral interactions and heavy metal immobilization in clay-rich natural environments.

Information

Type
Research Article
Copyright
Copyright © 2008, The Clay Minerals Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

References

Albinsson, Y. Cristiansen-satmark, B. Engkvist, I. and Johansson, W., 1991 Transport of actinides and Tc through a bentonite backfilling containing small quantities of iron or copper Radiochimica Acta 52/53 283286.10.1524/ract.1991.5253.1.283CrossRefGoogle Scholar
Amonette, J.E. and Fitch, A., 2003 Iron redox chemistry of clays and oxides: environmental applications Electrochemical Properties of Clays Aurora, Colorado, USA The Clay Minerals Society 89148.Google Scholar
Ammonette, J.E. Scott, A.D. and Churchman, G.J., 1995 Oxidative weathering of trioctahedral micas by buffered H2O2 solutions Clays Controlling the Environment Melbourne CSIRO Publishing 355361.Google Scholar
Amran, K. and Ganor, J., 2005 The combined effect of pH and temperature on smectite dissolution rate under acidic conditions Geochimica et Cosmochimica Acta 69 25352546.10.1016/j.gca.2004.10.001CrossRefGoogle Scholar
Andrade, S. Hypolito, R. Ulbrich, H.H. and Silva, M.L., 2002 Iron(II) oxide determination in rocks and minerals Chemical Geology 182 8589.10.1016/S0009-2541(01)00274-1CrossRefGoogle Scholar
Baeyens, B. and Bradbury, M.H., 1997 A mechanistic description of Ni and Zn sorption on Na-montmorillonite. Part I: Titration and sorption measurements Journal of Contaminant Hydrology 27 199222.10.1016/S0169-7722(97)00008-9CrossRefGoogle Scholar
Bradbury, M.H. and Baeyens, B., 2002 Sorption of Eu on Na-and Ca-montmorillonites: Experimental investigations and modeling with cation exchange and surface Geochimica et Cosmochimica Acta 66 23252334.10.1016/S0016-7037(02)00841-4CrossRefGoogle Scholar
Bratu, C. Bratu, G. Galateanu, I. and Roman, M., 1975 Study of lower valence states of technetium Journal of Radioanalytical Chemistry 26 516.10.1007/BF02516508CrossRefGoogle Scholar
Brusic, V. and Diggle, J.W., 1972 Passivation and passivity The Anodic Behavior of Metals and Semiconductors Series New York Marcel and Dekker, Inc. 180.Google Scholar
Buerge, I.J. and Hug, S.J., 1999 Influence of mineral surfaces on chromium(VI) reduction by iron(II) Environmental Science and Technology 33 42854291.10.1021/es981297sCrossRefGoogle Scholar
Bukka, K. Miller, J.D. and Shabtai, J., 1992 FTIR study of deuterated montmorillonites: Structural features relevant to pillared clay stability Clays and Clay Minerals 40 92102.10.1346/CCMN.1992.0400110CrossRefGoogle Scholar
Burke, I.T. Boothman, C. Lloyd, J.R. Mortimer, R.J.G. Livens, F.R. and Morris, K., 2005 Effects of progressive anoxia on the solubility of technetium in sediments Environmental Science and Technology 39 41094116.10.1021/es048124pCrossRefGoogle ScholarPubMed
Cantrell, K.J. Serne, R.J. and Last, G.V., 2003 Hanford Contaminant Distribution Coefficient Database and Users Guide Richland, Washington Pacific Northwest National Laboratory.10.2172/15010213CrossRefGoogle Scholar
Cardile, C.M. and Slade, P.G., 1987 Structural study of a benzidine-vermiculite intercalate having a high tetrahedral-iron content by 57Fe Mössbauer spectroscopy Clays and Clay Minerals 35 203207.10.1346/CCMN.1987.0350306CrossRefGoogle Scholar
Cataldo, D.A. Garland, T.R. Wildung, R.E. and Fellows, R.J., 1989 Comparative metabolic behaviour and interrelationships of Tc and S in soyabean plants Health Physics 57 281288.10.1097/00004032-198908000-00006CrossRefGoogle ScholarPubMed
Cervini-Silva, J., 2004 Coupled charge transfer- and hydrophilic-interactions between polychlorinated methanes, ethanes, and ethenes and redox-manipulated smectite clay minerals Langmuir 20 98789881.10.1021/la0491089CrossRefGoogle ScholarPubMed
Cervini-Silva, J. Larson, R.A. and Stucki, J.W., 2006 Hydration/expansion and cation charge compensation modulate the Bronsted basicity of distorted clay water Langmuir 22 21452151.10.1021/la0602113CrossRefGoogle ScholarPubMed
Charlet, L. Silvester, E. and Liger, E., 1998 N-compound reduction and actinide immobilization in surficial fluids by Fe(II): The surface =FeIIIOFeIIOHo species, as major reductant Chemical Geology 151 8593.10.1016/S0009-2541(98)00072-2CrossRefGoogle Scholar
Chisholm-Brause, C. Conradason, S.D. Buscher, C.T. Eller, P.G. and Morris, D.E., 1994 Speciation of uranyl sorbed at multiple binding sites on montmorillonite Geochimica et Cosmochimica Acta 58 36253631.10.1016/0016-7037(94)90154-6CrossRefGoogle Scholar
Cooper, D.C. Picardal, F. Rivera, J. and Talbot, C., 2000 Zinc immobilization and magnetite formation via ferric oxide reduction by Shewanella putrefaciens 200 Environmental Science and Technology 34 100106.10.1021/es990510xCrossRefGoogle Scholar
Cui, D. and Eriksen, T., 1996 Reduction of pertechnetate in solution by heterogeneous electron transfer from Fe(II)-containing geological material Environmental Science and Technology 30 22632269.10.1021/es950627vCrossRefGoogle Scholar
Dong, H. Kostka, J.E. and Kim, J.W., 2003 Microscopic evidence for microbial dissolution of smectite Clays and Clay Minerals 51 502512.10.1346/CCMN.2003.0510504CrossRefGoogle Scholar
Dong, H. Kukkadapu, R.K. Fredrickson, J.K. Zachara, J.M. Kennedy, D.W. and Kostandarithes, H.M., 2003 Microbial reduction of structural Fe(III) in illite and goethite Environmental Science and Technology 37 12681276.10.1021/es020919dCrossRefGoogle Scholar
Elsner, M. Schwarzenbach, R.P. and Haderlein, S.B., 2004 Reactivity of Fe(II) bearing minerals towards reductive transformation of organic contaminants Environmental Science and Technology 38 799807.10.1021/es0345569CrossRefGoogle Scholar
Favre, F. Bogdal, C. Gavillet, S. and Stucki, J.W., 2006 Changes in the CEC of a soil smectite-kaolinite clay fraction as induced by structural iron reduction and iron coatings dissolution Applied Clay Science 34 95104.10.1016/j.clay.2006.04.010CrossRefGoogle Scholar
Fialips, C.-I. Huo, D. Yan, L. Wu, J. and Stucki, J.W., 2002 Infrared study of reduced and reduced-reoxidized ferruginous smectite Clays and Clay Minerals 50 455469.10.1346/000986002320514181CrossRefGoogle Scholar
Foster, W.R. Savins, J.G. and Waite, J.M., 1955 Lattice expansion and rheological behavior of relationships in water-montmorillonite systems Clays and Clay Minerals 395 296316.Google Scholar
Fredrickson, J.K. Zachara, J.M. Kennedy, D.W. Dong, H. Onstott, T.C. Hinman, N.W. and Shu-mei, L., 1998 Biogenic iron mineralization accompanying the dissimilatory reduction of hydrous ferric oxide by a groundwater bacterium Geochimica et Cosmochimica Acta 62 32393257.10.1016/S0016-7037(98)00243-9CrossRefGoogle Scholar
Fredrickson, J.K. Zachara, J.M. Kennedy, D.W. Kukadappu, R.K. Mckinley, J.P. Heald, S.M. Liu, C. and Plymale, A.E., 2004 Reduction of TcO4 by sediment-associated biogenic Fe(II) Geochimica et Cosmochimica Acta 68 31713187.10.1016/j.gca.2003.10.024CrossRefGoogle Scholar
Furukawa, Y. and O’Reilly, S.E., 2007 Rapid precipitation of amorphous silica in experimental systems with nontronite (NAu-1) and Shewanella oneidensis MR-1 Geochimica et Cosmochimica Acta 71 363377.10.1016/j.gca.2006.09.006CrossRefGoogle Scholar
Gan, H. Bailey, G.W. and Yu, Y.S., 1996 Morphology of lead(II) and chromium(III) reaction products on phyllosilicate surfaces as determined by atomic force microscopy Clays and Clay Minerals 44 734743.10.1346/CCMN.1996.0440603CrossRefGoogle Scholar
Gates, W.P. Slade, P.G. Manceau, A. and Lanson, B., 2002 Site occupancies by iron in nontronites Clays and Clay Minerals 50 223239.10.1346/000986002760832829CrossRefGoogle Scholar
Gates, W.P. Wilkinson, H.T. and Stucki, J.W., 1993 Swelling properties of microbially reduced ferruginous smectite Clays and Clay Minerals 41 360364.10.1346/CCMN.1993.0410312CrossRefGoogle Scholar
Giaquinta, D.M. Soderholm, L. Yuchs, S.E. and Wasserman, S.R., 1997 The speciation of uranium in a smectite clay: evidence for catalyzed uranyl reduction Radiochimica Acta 76 113121.CrossRefGoogle Scholar
Haderlein, S.B. Weissmahr, K.W. and Schwarzenbach, R.P., 1996 Specific adsorption of nitroaromatic explosives and pesticides to clay minerals Environmental Science and Technology 30 612622.10.1021/es9503701CrossRefGoogle Scholar
Hess, N.J. Xia, Y. Rai, D. and Conradson, S.D., 2004 Thermodynamic model for the solubility of TcO2·xH2O(am) in the aqueous Tc(IV)-Na+-Cl-H+-OH-H2O system Journal of Solution Chemistry 33 199226.10.1023/B:JOSL.0000030285.11512.1fCrossRefGoogle Scholar
Hofstetter, T.B. Neumann, A. and Schwarzenbach, R.P., 2006 Reduction of nitroaromatic compounds by Fe(II) species associated with iron-rich smectites Environmental Science and Technology 40 235242.10.1021/es0515147CrossRefGoogle ScholarPubMed
Hofstetter, T.B. Schwarzenbach, R.P. and Haderlein, S.B., 2003 Reactivity of Fe(II) species associated with clay minerals Environmental Science and Technology 37 519528.10.1021/es025955rCrossRefGoogle ScholarPubMed
Ilton, E.S. Haiduc, A. Moses, C.O. Heald, S.M. Elbert, D.C. and Veblen, D.R., 2004 Heterogeneous reduction of uranyl by micas: Crystal chemical and solution controls Geochimica et Cosmochimica Acta 68 24172435.10.1016/j.gca.2003.08.010CrossRefGoogle Scholar
Ilton, E.S. Veblen, D.R. Moses, C.O. and Raeburn, S.P., 1997 The catalytic effect of sodium and lithium ions on coupled sorption-reduction of chromate at the biotite edge-fluid interface Geochimica et Cosmochimica Acta 61 35433563.10.1016/S0016-7037(97)00185-3CrossRefGoogle Scholar
Jaisi, D.P. Kukkadapu, R.K. Eberl, D.D. and Dong, H., 2005 Control of Fe(III) site occupancy on the rate and extent of microbial reduction of Fe(III) in nontronite Geochimica et Cosmochimica Acta 69 54295440.10.1016/j.gca.2005.07.008CrossRefGoogle Scholar
Jaisi, D.P. Dong, H. and Liu, C., 2007 Analysis of Fe(III) reduction kinetics in nontronite Environmental Science and Technology 41 24342444.10.1021/es0619399CrossRefGoogle ScholarPubMed
Jaisi, D.P. Dong, H. and Liu, C., 2007 Influence of biogenic Fe(II) on the extent of microbial reduction of Fe(III) in clay minerals nontronite, illite, and chlorite Geochimica et Cosmochimica Acta 71 11451158.10.1016/j.gca.2006.11.027CrossRefGoogle Scholar
Katoh, S. Danhara, T. Hart, W.K. and Wolde-Gabriel, G., 1999 Use of sodium polytungstate solution in the purification of volcanic glass shards for bulk chemical analysis Natural Human Acta 4 4554.Google Scholar
Katz, N. and Hazen, T.C. (2005) High throughput analysis of stress response in Shewanella oneidensis MR-1. ().Google Scholar
Keeling, J.L. Raven, M.D. and Gates, W.P., 2000 Geology and characterization of two hydrothermal nontronites from weathered metamorphic rocks at the Uley graphite mine, South Australia Clays and Clay Minerals 48 537548.10.1346/CCMN.2000.0480506CrossRefGoogle Scholar
Khaled, E.M. and Stucki, J.W., 1991 Effects of iron oxidation state on cation fixation in smectites Soil Science Society of America Journal 55 550554.10.2136/sssaj1991.03615995005500020045xCrossRefGoogle Scholar
Kim, J.W. Dong, H. Seabaugh, J. Newell, S.W. and Eberl, D.D., 2004 Role of microbes in the smectite-to-illite reaction Science 303 830832.10.1126/science.1093245CrossRefGoogle ScholarPubMed
Komadel, P. Madejová, J. and Stucki, J. W., 2006 Structural Fe(III) reduction in smectites Applied Clay Science 34 8894.CrossRefGoogle Scholar
Kostka, J.E. Stucki, J.W. Nealson, K.H. and Wu, J., 1996 Reduction of structural Fe(III) in smectite by a pure culture of Shewanella putrefaciens strain MR-1 Clays and Clay Minerals 44 522529.10.1346/CCMN.1996.0440411CrossRefGoogle Scholar
Kostka, J.E. Haefele, E. Viehweger, R. and Stucki, J.W., 1999 Respiration and dissolution of iron(III)-containing clay minerals by bacteria Environmental Science and Technology 33 31273133.10.1021/es990021xCrossRefGoogle Scholar
Kukkadapu, R.K. Zachara, J.M. Fredrickson, J.K. McKinley, J.P. Kennedy, D.W. Smith, S.C. and Dong, H., 2006 Reductive biotransformation of Fe in shale-limestone saprolite containing Fe(III) oxides and Fe(II)/Fe(III) phyllosilicates Geochimica et Cosmochimica Acta 70 36623676.10.1016/j.gca.2006.05.004CrossRefGoogle Scholar
Lear, P.R. and Stucki, J.W., 1987 Intervalence electron transfer and magnetic exchange in reduced nontronite Clays and Clay Minerals 35 373378.10.1346/CCMN.1987.0350507CrossRefGoogle Scholar
Lear, P.R. and Stucki, J.W., 1989 Effects of iron oxidation state on the specific surface area of nontronite Clays and Clay Minerals 37 547552.10.1346/CCMN.1989.0370607CrossRefGoogle Scholar
Lee, K. Kostka, J.E. and Stucki, J.W., 2006 Comparisons of structural Fe reduction in smectites by bacteria and dithionite: An infrared spectroscopic study Clays and Clay Minerals 54 195208.10.1346/CCMN.2006.0540205CrossRefGoogle Scholar
Li, Y.-L. Vali, H. Sears, S.K. Yang, J. Deng, B. and Zhang, C.L., 2004 Iron reduction and alteration of nontronite NAu-2 by a sulfate-reducing bacterium Geochimica et Cosmochimica Acta 68 32513260.10.1016/j.gca.2004.03.004CrossRefGoogle Scholar
Lieser, K.H. and Bauscher, C., 1988 Technetium in the hydrosphere and in the geosphere: influence of pH of complexing agents and of some minerals on the sorption of technetium Radiochimica Acta 44 125128.10.1524/ract.1988.4445.1.125CrossRefGoogle Scholar
Liu, C. Zachara, J.M. Zhong, L. Kukkadupa, R. Szecsody, J.E. and Kennedy, D.W., 2005 Influence of sediment bioreduction and reoxidation on uranium sorption Environmental Science and Technology 39 41254133.10.1021/es048501yCrossRefGoogle ScholarPubMed
Lloyd, J.R. Sole, V.A. Van Praagh, C.V.G. and Lovley, D.R., 2000 Direct and Fe(II)-mediated reduction of technetium by Fe(III)-reducing bacteria Applied and Environmental Microbiology 66 37433749.10.1128/AEM.66.9.3743-3749.2000CrossRefGoogle ScholarPubMed
Luther, G.W. Shellenbarger, A. and Brendel, P.J., 1996 Dissolved organic Fe(III) and Fe(II) complexes in salt marsh porewaters Geochimica et Cosmochima Acta 60 951960.10.1016/0016-7037(95)00444-0CrossRefGoogle Scholar
Manceau, A. Lanson, B. Drits, V.A. Chateigner, D. Gates, W.P. Wu, J. Huo, D. and Stucki, J.W., 2000 Oxidation-reduction mechanism of iron in dioctahedral smectites. 1. Crystal chemistry of oxidized reference nontronites American Mineralogist 85 133152.10.2138/am-2000-0114CrossRefGoogle Scholar
Manceau, A. Lanson, B. Drits, V.A. Chateigner, D. Wu, J. Huo, D. Gates, W.P. and Stucki, J. W., 2000 Oxidation-reduction mechanism of iron in dioctahedral smectites. 2. Structural chemistry of reduced Garfield nontronite American Mineralogist 85 153172.10.2138/am-2000-0115CrossRefGoogle Scholar
Morris, H.D. Shelton, B. and Ellis, P.D., 1990 27Al NMR spectroscopy of iron bearing montmorillonite clays Journal of Physical Chemistry 94 31213129.10.1021/j100370a069CrossRefGoogle Scholar
Morrison, S.R., 1980 Electrochemistry at Semiconductor and Oxidized Metal Electrodes New York Plenum.10.1007/978-1-4613-3144-5CrossRefGoogle Scholar
NAGRA, 2002 Project Opalinus Clay: Safety report. Demonstration of disposal feasibility for spent fuel, vitrified high-level waste and long lived intermediate level waste Wettingen, Switzerland Nagra.Google Scholar
O’Reilly, S.E. Watkins, J. and Furukawa, Y., 2005 Secondary mineral formation associated with respiration of nontronite, NAu-1 by iron reducing bacteria Geochemical Transactions 6 6778.CrossRefGoogle ScholarPubMed
O’Reilly, S.E. Furukawa, Y. and Newell, S., 2006 Dissolution and microbial Fe(III) reduction of nontronite (NAu-1) Chemical Geology 235 111.10.1016/j.chemgeo.2006.05.010CrossRefGoogle Scholar
Qafoku, N.P. Ainsworth, C. Szecsody, J.E. Qafoku, O.S. and Heald, S.M., 2003 Effect of coupled dissolution and redox reactions on Cr(VI)aq attenuation during transport in the sediments under hyperalkaline conditions Environmental Science and Technology 37 36403646.10.1021/es020935aCrossRefGoogle ScholarPubMed
Rhoades, J.D. Ingvalson, R.D. and Stumpf, H.T., 1969 Interlayer spacing of expanded clay minerals at various swelling pressures: an X-ray diffraction technique for direct determination Soil Science Society of America Journal 33 473475.10.2136/sssaj1969.03615995003300030038xCrossRefGoogle Scholar
Riley, R.G. and Zachara, J.M., 1992 Chemical Contaminants on DOE Lands and Selection of Contaminant Mixtures for Subsurface Science Research Washington, D.C U.S. Department of Energy.Google Scholar
Rozenson, I. and Heller-Kallai, L., 1976 Reduction and oxidation of Fe(III) in dioctahedral smectite-l: reduction with hydrazine and dithionite Clays and Clay Minerals 24 271282.10.1346/CCMN.1976.0240601CrossRefGoogle Scholar
Scott, A.D. and Amonette, J. (1988) The Role of Iron in Mica Weathering. NATO ASI Series, C: pp. 537623.10.1007/978-94-009-4007-9_16CrossRefGoogle Scholar
Shen, S. Stucki, J.W., Havlin, J.L. Jacobsen, J. Fixen, P. and Hergert, G., 1994 Effects of iron oxidation state on the fate and behavior of potassium in soils Soil Testing: Prospects for Improving Nutrient Recommendations Madison, Wisconsin Soil Science Society of America 173185.Google Scholar
Silvester, E. Charlet, L. Tournassat, C. Gehin, A. Greneche, J.-M. and Liger, E., 2005 Redox potential measurements and Mössbauer spectrometry of Fe(II) adsorbed onto Fe(III) (oxyhydr)oxides Geochimica et Cosmochimica Acta 69 48014815.10.1016/j.gca.2005.06.013CrossRefGoogle Scholar
Skinner, M.F. Zabowski, D. Harrison, R. Lowe, A. and Xue, D., 2001 Measuring the cation exchange capacity of forest soils Communications in Soil Science and Plant Analysis 32 17511764.10.1081/CSS-120000247CrossRefGoogle Scholar
Sposito, G. and Prost, R., 1982 Structure of water adsorbed on smectites Chemical Revisions 82 553573.10.1021/cr00052a001CrossRefGoogle Scholar
Stookey, L.L., 1970 Ferrozine — a new spectrophotometric reagent for iron Analytical Chemistry 42 779781.10.1021/ac60289a016CrossRefGoogle Scholar
Stucki, J.W., Bergaya, F. Lagaly, G. and Theng, B.K.G., 2006 Iron redox processes in clay minerals Handbook of Clay Science Amsterdam Elsevier 429482.Google Scholar
Stucki, J.W. and Huo, D. (1996) Effects of Cation Competition on Potassium Fixation. Proceedings of the Illinois Fertilizer Conference, Illinois.Google Scholar
Stucki, J.W. and Kostka, J.E., 2006 Microbial reduction of iron in smectite Comptes Rendus Geoscience 338 468475.10.1016/j.crte.2006.04.010CrossRefGoogle Scholar
Stucki, J.W. Golden, D.C. and Roth, C.B., 1984 Preparation and handling of dithionite-reduced smectite suspensions Clays and Clay Minerals 32 191197.10.1346/CCMN.1984.0320306CrossRefGoogle Scholar
Stucki, J.W. Golden, D.C. and Roth, C.B., 1984 Effect of reduction and reoxidation of structural iron on the surface charge and dissolution of dioctahedral smectites Clays and Clay Minerals 32 350356.10.1346/CCMN.1984.0320502CrossRefGoogle Scholar
Stucki, J.W. Lee, K. Zhang, L. and Larson, R.A., 2002 The effects of iron oxidation state on the surface and structural properties of smectites Pure and Applied Chemistry 74 20792092.10.1351/pac200274112145CrossRefGoogle Scholar
Stumm, W. and Morgan, J.J., 1996 Aquatic Chemistry New York Wiley.Google Scholar
Taylor, R.W. Shen, S. Bleam, W.F. and Tu, S.I., 2000 Chromate removal by dithionite-reduced clays: evidence from direct X-ray absorption near edge spectroscopy (XANES) of chromate reduction at clay surfaces Clays and Clay Minerals 48 648654.10.1346/CCMN.2000.0480606CrossRefGoogle Scholar
Viani, B.E. Low, P.F. and Roth, C.B., 1983 Direct measurement of the relation between interlayer force and interlayer distance in the swelling of montmorillonite Colloidal and Interface Science 96 229244.10.1016/0021-9797(83)90025-5CrossRefGoogle Scholar
Weissmahr, K.W. Haderlein, S.B. Schwarzenbach, R.P. Hany, R. and Nuesch, R., 1996 In situ spectroscopic investigations of adsorption mechanisms of nitroaromatic compounds at clay minerals Environmental Science and Technology 31 240247.10.1021/es960381+CrossRefGoogle Scholar
Wildung, R.E. Gorby, Y.A. Krupka, K.M. Hess, N.J. Li, S.W. Plymale, A.E. McKinley, J.P. and Fredrickson, J.K., 2000 Effect of electron donor and solution chemistry on products of dissimilatory reduction of technetium by Shewanella putrefaciens. Applied and Environmental Microbiology 66 24512460.10.1128/AEM.66.6.2451-2460.2000CrossRefGoogle Scholar
Wildung, R.E. Li, S.W. Murray, C.J. Krupka, K.M. Xie, Y. Hess, N.J. and Roden, E.E., 2004 Technetium reduction in sediments of a shallow aquifer exhibiting dissimilatory iron reduction potential FEMS Microbiology and Ecology 49 151162.10.1016/j.femsec.2003.08.016CrossRefGoogle ScholarPubMed
Williams, A.G.B. and Scherer, M.M., 2004 Spectroscpoic evidence for Fe(II)-Fe(III) electron transfer at iron oxide-water interface Environmental Science and Technology 38 47824790.10.1021/es049373gCrossRefGoogle Scholar
Wu, J. Roth, C.B. and Low, P.F., 1988 Biological reduction of structural iron in sodium-nontronite Soil Science Society of America Journal 52 295296.10.2136/sssaj1988.03615995005200010054xCrossRefGoogle Scholar
Zachara, J.M. Fredrickson, J.K. Li, S.W. Kennedy, D.W. Smith, S.C. and Gassman, P.L., 1998 Bacterial reduction of crystalline Fe(III) oxides in single phase suspension and subsurface materials American Mineralogist 83 14261443.10.2138/am-1998-11-1232CrossRefGoogle Scholar
Zachara, J.M. Heald, S.M. Jeon, B.-H. Kukkadapu, R.K. Dohnalkova, A.C. McKinley, J.P. Moore, D.A. and Liu, C., 2007 Reduction of pertechnetate [Tc(VII)] by aqueous Fe(II) and the nature of solid phase redox products Geochimica et Cosmochimica Acta 71 21372157.10.1016/j.gca.2006.10.025CrossRefGoogle Scholar