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Alkali Cation Selectivity and Fixation by Clay Minerals

Published online by Cambridge University Press:  01 July 2024

Dennis D. Eberl
Dennis D. Eberl*
Affiliation:
Department of Geology, University of Illinois, 61801, Urbana, Illinois, USA
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Abstract

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Two variables must be considered when calculating exchange free energies (ΔG°ex) for 2:1 clays: (1) anionic field strength, as expressed by equivalent anionic radius (ra), and (2) interlayer water content, as expressed by interlayer molality. For smectites that are in a state of high hydration, interlayer molality is determined by the cations undergoing exchange. Thus ΔG°ex for an exchanging cation pair can be calculated solely from measurements of ra. ra is related to layer charge per half unit cell (C) and ab unit cell area (A) by: ra = (-A/8πC)1/2. The layer charge necessary for cation fixation can be predicted by calculating the ra at which cation exchange with an illite structure expresses a AG°ex equal to that of exchange with a smectite structure. The theory can also be applied qualitatively to understand the high selectivity of illite for Cs+, the fixation of K+ rather than Na+ in shales during diagenesis, the stability of illite over muscovite in the weathering environment, and cation segregation in smectite.

Резюме

Резюме

При вычислении свободных энергий обмена (ΔC°ех) для глин 2:1 необходимо рассматривать две переменненные (1) силу анионного поля, выраженную в виде эквивалентного анионного радиуса (ra), и (2) содержание межслойной воды, вырвженное в виде межслойной мольности. Для смективов, которые находятся в состоянии высокой гидротации, межслойная мольность обуслав- левается катионами, повергающимися обмену. Таким образом, ΔC°eх для пары обмениваемых катионов может быть вычислена исключительно по данным измерений га. Величина га связана с зарядом слоя на половину элементарной ячейки, (С), и с площадью (А) элементарной ячейки ab соотношением га = (-А/8π-С)12. Заряд слоя, необходимого для фиксации катиона, может быть предсказан вычислением га при котором катионный обмен с иллитовой структурой выражает ДСех равный ΔG°ex обмена со смектитовой структурой. Эту теорию можно также применить качественно, чтобы понять высокую селективность иллита для Cs+, фиксацию K+ вместо Na+ в сланцах во время диагенеза, устойчивость иллита по сравнению с мусковитом в среде выветривания и сегрегацию катионов в смектите. [N.R.]

Resümee

Resümee

Zwei Variable müssen bei der Berechnung der freien Austauschenergie (ΔG°ex) bei 2:1 Tonen berücksichtigt werden: (1) die Anionenfeldstärke, wie sie durch den äquivalenten Anionenradius (ra) ausgedrückt wird und (2) der Zwischenschichtwassergehalt, wie er durch die Zwischenschichtmolalität gegeben ist. Bei Smektiten, die sich in einem Stadium großer Hydratation befinden, wird die Zwischenschichtmolalität durch die austauschbaren Kationen bestimmt. Daher kann ΔG°ex für ein Austauschkationenpaar nur durch die Bestimmung von ra berechnet werden. Der Wert von ra steht in Beziehung zur Schichtladung pro halber Einheitszelle (C) und ab Einheitszellenbereich (A) durch: ra = (-A/8πC)1/2. Die Ladungsdichte, die für die Kationenfixierung notwendig ist, kann vorausgesagt werden, indem der ra berechnet wird, bei dem der Kationenaustausch mit einer Illitstruktur ein ΔG°ex gleich dem eines Kationenaustausches mit einer Smektitstruktur ausdrückt. Diese Theorie kann auch qualitativ verwendet werden, um die große Selektivität des Mit für Cs+ zu verstehen, die Fixierung von K+ vor Na+ in Schiefertonen während der Diagenese, die Stabilität des Illits gegenüber Muskovit unter Verwitterungsbedingungen und die Kationenentmischung in Smektit. [U.W.]

Résumé

Résumé

Deux variables doivent être considérées lorsqu'on calcule l’échange d’énergies libres AG°ex des argiles 2:1: (1) la force de champ anionique, exprimée par le rayon équivalent ra, et (2) la teneur en eau interfeuillet, exprimée par la molalité interfeuillet. Pour les smectites qui sont dans un état d'hydratation élevée, la molalité interfeuillet est déterminée par les cations subissant l’échange. De cette manière, ΔG°ex pour une paire de cations échangeants ne peut être calculé qu’à partir de la mesure de ra. La valeur ra est apparentée à la charge de feuillet par Vi maille (C) et par surface de maille ab (A) par ra = (-A/8πC)1/2. La charge de feuillet nécessaire pour la fixation de cation peut être prédite en calculant la valeur ra à laquelle l’échange de cation avec une structure illite exprime une valeur AG°ex égale à celle de l’échange avec une structure smectite. La théorie peut aussi être appliquée qualitativement pour comprendre la haute sélectivité de Milite pour Cs+, la fixation de K+ plutôt que Na+ dans les roches argileuses pendant la diagénèse, la plus grande stabilité de Milite que de la muscovite dans un environement d'altération, et la ségrégation de cations dans la smectite. [D.J.]

Keywords

Cation exchangeCation fixationCation selectivityEquivalent anionic radiusFree energy of exchangeIlliteSmectite
Type
Research Article
Information
Clays and Clay Minerals , Volume 28 , Issue 3 , June 1980 , pp. 161 - 172
Copyright
Copyright © Clay Minerals Society 1980

References

Banin, A. and Ravikovitch, S., (1966) Kinetics of reactions in the conversion of Na- or Ca-saturated clay to H-Al clay Clays & Clay Minerals 14 193–204.CrossRefGoogle Scholar
Barshad, I., (1950) The effect of the interlayer cations on the expansion of the mica type of crystal lattice Amer. Mineral. 35 225–238.Google Scholar
Bernal, J. D. and Fowler, R. H., (1933) A theory of water and ionic solution, with particular reference to hydrogen and hydroxyl ions J. Chem. Phys. 1 515–548.CrossRefGoogle Scholar
Blackmon, P. D., (1958) Neutralization curves and the formulation of monovalent cation exchange properties of clay minerals Amer. J. Sci. 256 733–743.CrossRefGoogle Scholar
Brindley, G. W. and MacEwan, D. M. C., (1953) Structural aspects of the mineralogy of clays Ceramics—A Symposium Stoke-on-Trent The British Ceramic Society 15–59.Google Scholar
Brown, G. and Weir, A. H., (1965) An addition to the paper “The identity of rectorite and allevardite” Proc. Internat. Clay Conf. 2 87–90.Google Scholar
Cruickshank, E. H. and Meares, P., (1957) The thermodynamics of cation exchange. Part 2: Comparison between resins and concentrated choride solutions Trans. Faraday Soc. 53 1299–1308.CrossRefGoogle Scholar
Eberl, D. D. and Hower, J., (1976) Kinetics of illite formation Geol. Soc. Amer. Bull. 87 1326–1330.2.0.CO;2>CrossRefGoogle Scholar
Eberl, D. D. and Hower, J., (1977) The hydrothermal transformation of sodium and potassium smectite into mixed-layer clay Clays & Clay Minerals 25 215–228.CrossRefGoogle Scholar
Eisenman, G., Kleinzeller, A. and Kotyk, A., (1961) On the elementary origin of equilibrium ionic specificity Symposium on Membrane Transport and Metabolism New York Academic Press 163–179.Google Scholar
Eisenman, G., (1962) Cation selective glass electrodes and their mode of operation Biophys. J. 2 259–323.CrossRefGoogle ScholarPubMed
Eliason, J. R., (1966) Montmorillonite exchange equilibria with strontium-sodium-cesium Amer. Mineral. 51 324–335.Google Scholar
Faucher, J. A. and Thomas, H. C., (1954) Adsorption studies on clay minerals. IV. The system montmorillonite-cesium- potassium J. Chem. Phys. 22 258–261.CrossRefGoogle Scholar
Friedman, H. L. Krishnan, C. V. and Franks, F., (1973) Thermodynamics of ionic hydration Water, A Comprehensive Treatise 3 New York Plenum Press 1–118.Google Scholar
Gaines, G. L. and Thomas, H. C., (1953) Adsorption studies on clay minerals. III. A formulation of the thermodynamics of exchange adsorption J. Chem. Phys. 21 714–718.CrossRefGoogle Scholar
Garrels, R. M. and Christ, C. L., (1965) Solutions, Minerals and Equilibria New York Harper and Row, Inc..Google Scholar
Garrels, R. M. and Howard, P., (1959) Reactions of feldspar and mica with water at low temperature and pressure Clays & Clay Minerals 6 68–88.Google Scholar
Gast, R. G., (1969) Standard free energies of exchange for alkali metal cations on Wyoming bentonite Soil Sci. Soc. Amer. Proc. 33 37–41.CrossRefGoogle Scholar
Gast, R. G. and Klobe, W. D., (1971) Sodium-lithium exchange equilibria on Vermiculite at 25°C and 50°C Clays & Clay Minerals 19 311–319.CrossRefGoogle Scholar
Gaudette, H. E. Grim, R. E. and Metzger, C. F., (1966) Illite: a model based on sorption behavior of cesium Amer. Mineral. 51 1649–1656.Google Scholar
Gaultier, J. P. Mamy, J., Mortland, M. M. and Farmer, V. C., (1979) Evolution of exchange properties and crystallographic characteristics of biionic K-Ca montmorillonite submitted to alternate wetting and drying Internat. Clay Conf. 1978 Amsterdam Elsevier 167–175.Google Scholar
Grim, R. E., (1968) Clay Mineralogy 2nd ed. New York McGraw-Hill.Google Scholar
Grim, R. E. and Güven, N., (1978) Bentonites Amsterdam Elsevier.Google Scholar
Hower, J. and Mowatt, T. C., (1966) Mineralogy of the illiteillite/montmorillonite group Amer. Mineral. 51 821–854.Google Scholar
Hower, J. Eslinger, E. V. Hower, M. E. and Perry, E. A., (1976) Mechanism of burial metamorphism of argillaceous sediment: 1. Mineralogical and chemical evidence Geol. Soc. Amer. Bull. 87 725–737.2.0.CO;2>CrossRefGoogle Scholar
Jackson, M. L., (1963) Interlayering of expansible layer silicates in soils by chemical weathering Clays & Clay Minerals 11 29–46.Google Scholar
Kodama, H., (1966) The nature of the component layers of rectorite Amer. Mineral. 51 1035–1055.Google Scholar
Lagaly, G. and Weiss, A., (1976) The layer charge of smectitic layer silicates Proc. Internat. Clay Conf. 1975 157–172.Google Scholar
McAtee, J. L., (1956) Random interstratification in montmorillonite Amer. Mineral. 41 627–631.Google Scholar
Méring, J. and Glaeser, R., (1953) Cations éxchangeables dans montmorillonite Bull. Groupe Fr. Argiles 5 61–72.Google Scholar
Norrish, K., (1954) The swelling ofmontmorillonite Discuss. Faraday Soc. 18 120–134.CrossRefGoogle Scholar
Norrish, K., (1973) Factors in the weathering of mica to Vermiculite Proc. Internat. Clay Conf 1972 417–432.Google Scholar
Perry, E. A. and Hower, J., (1970) Burial diagenesis in Gulf Coast pelitic sediments Clays & Clay Minerals 18 165–178.CrossRefGoogle Scholar
Robinson, R. A. and Stokes, R. H., (1959) Electrolyte Solutions 2nd ed. London Butterworths Scientific Publications.Google Scholar
Rossini, F. D., Wagman, D. D., Evans, W. D., Levine, S., and Jaffe, I. (1952) Selected values of chemical thermodynamic properties: Nat. Bur. Stand. Circ. 500, U.S. Gov. Printing Office, Washington, D.C., 1268 pp.Google Scholar
Sawhney, B. L., (1972) Selective sorption and fixation of cations by clay minerals: a review Clays & Clay Minerals 20 93–100.CrossRefGoogle Scholar
Sears, F. W. and Zemansky, M. W., (1955) University Physics 2nd ed. Reading, Massachusetts Addison-Wesley.Google Scholar
Scott, A. D., (1968) Effect of particle size on interlayer potassium exchange in micas Trans. 9th Int. Congr. Soil Sci. 2 649–660.Google Scholar
Scott, A. D. and Smith, S. J., (1966) Susceptibility of interlayer potassium in micas to exchange with sodium Clays & Clay Minerals 14 69–81.CrossRefGoogle Scholar
Stokes, R. H. and Robinson, R. A., (1948) Ionic hydration and activity in electrolyte solutions J. Amer. Chem. Soc. 70 1870–1878.CrossRefGoogle ScholarPubMed
Tabikh, A. A. Barshad, I. and Overstreet, R., (1960) Cation exchange histeresis in clay minerals Soil Sci. 90 219–226.CrossRefGoogle Scholar
Tamura, T. and Jacobs, D. G., (1960) Structural implications in cesium sorption Health Phys. 2 391–398.CrossRefGoogle ScholarPubMed
Tamura, T. and Jacobs, D. G., (1961) Improving cesium selectivity of bentonites by heat treatment Health Phys. 5 149–154.CrossRefGoogle ScholarPubMed
Tarasevich, Y. L. Orazmuradov, A. O. and Ovcharenko, F. D., (1971) Heat of adsorption of water on cation-substituted vermiculite Colloid J. USSR 33 496–500 (Eng. Transi.).Google Scholar
Truesdell, A. H. and Christ, C. L., (1968) Cation exchange in clays interpreted by regular solution theory Amer. J. Sci. 266 402–412.CrossRefGoogle Scholar
Weaver, C. E. and Beck, K. C., (1971) Clay water diagenesis during burial: How mud becomes gneiss U.S. Geol. Surv. Prof. Pap. 134 1–78.Google Scholar