Hostname: page-component-848d4c4894-pjpqr Total loading time: 0 Render date: 2024-07-07T19:36:08.144Z Has data issue: false hasContentIssue false
  • English
  • Français

Far Infrared Analysis of the Structural Environment of Interlayer K+, NH4+, Rb+ and Cs+ Selectively Retained by Vermiculite

Published online by Cambridge University Press:  01 January 2024

M. Diaz ,
E. Huard  and
R. Prost
M. Diaz
Affiliation:
Unité de Science du Sol, Route de Saint Cyr, 78026 Versailles Cedex, France
E. Huard
Affiliation:
Unité de Science du Sol, Route de Saint Cyr, 78026 Versailles Cedex, France
R. Prost*
Affiliation:
Unité de Science du Sol, Route de Saint Cyr, 78026 Versailles Cedex, France
*
*E-mail address of corresponding author: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

To get a better understanding of the mechanisms of selective retention of cations by clay minerals, we have studied the physicochemical state and the location of immobilized cations. The approach developed is based on the concomitant study of the exchange isotherms and the compensating cations/clay structure interactions, using far infrared (FIR) spectroscopy. For that, cations are used as spectroscopic probes to characterize the selective sites.

Exchanged K, Rb-, K, Cs-, K, NH4- and NH4, Cs-Llano vermiculite samples were prepared. The exchange isotherms illustrate the higher selectivity of Llano vermiculite in the following order: K+ < Rb+ < Cs+. Desorption experiments show that a 2 N MgCl2 solution can extract a small fraction of immobilized Cs+. The concomitant analyses of the exchange phenomena at microscopic (X-ray diffraction) and molecular (far and middle IR spectroscopy) levels show that: (1) only ∼65% of the interlamellar hydrated Mg2+ of Llano vermiculite is exchanged; (2) cations are randomly distributed in the interlamellar spaces; and (3) retention is strongly related to the distance between compensating cations and oxygen atoms of the ditrigonal cavity.

The low hydration energy of selectively retained cations induces strong cation/clay interactions, which give FIR absorption bands of compensating cations. The FIR absorption bands of smaller cations shift towards lower wavenumbers when the proportion of the larger cations increases, whereas the wavenumber of the larger ones is constant. This reproducible scenario shows that larger cations act as wedges and expand layers, thus increasing the distance between the smaller cations and the layers. Calculation of the distances dM-O inner and dM-O outer shows that selectively-retained cations are six-coordinated in these dehydrated systems. The decrease of the difference between dM-O outer and dM-O inner from K+ to Cs+ may explain the observed selectivity of Llano vermiculite.

Keywords

Cation/Clay InteractionsFar Infrared SpectroscopyRetentionSelectivityVermiculite
Type
Research Article
Information
Clays and Clay Minerals , Volume 50 , Issue 2 , April 2002 , pp. 284 - 293
Copyright
Copyright © 2002, 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.)

References

Bailey, S.W., (1982) Nomenclature for regular interstratifications American Mineralogist 67 394 398.Google Scholar
De La Calle, C. Suquet, H. and Bailey, S.W., (1988) Vermiculite Hydrous Silicates Washington D.C. Mineralogical Society of America 455–496 Reviews in Mineralogy, 19 .Google Scholar
De La Calle, C. Suquet, H. and Pezerat, H., (1985) Vermiculites hydratées à une couche Clay Minerals 20 221–230 10.1180/claymin.1985.020.2.06.CrossRefGoogle Scholar
Diaz, M., (1999) Etude des interactions cations compensateurs/feuillets dans les argiles: contribution a la connaissance des mécanismes de retention sélective Orléans, France Univ. Orléans 135 p.Google Scholar
Donnay, G. Donnay, J.D.H. and Takeda, H., (1964) Trioctahedral one-layer micas. II. Prediction of the structure from composition and cell dimensions Acta Crystallographica 17 1374–1381 10.1107/S0365110X64003462.CrossRefGoogle Scholar
Farmer, V.C. and Farmer, V.C., (1974) The layer silicates The Infrared Spectra of Minerals London Mineralogical Society 331–338 10.1180/mono-4.15 Monograph, 4 .CrossRefGoogle Scholar
Fripiat, J.J. and Fripiat, J.J., (1981) Application of far infrared spectroscopy to the study of clay minerals and zeolites Advanced Techniques for Clay Minerals Analysis Amsterdam Elsevier 191 210.Google Scholar
Fripiat, J.J., Chaussidon, J. and Jelli, A. (1971) Chimie-physique des Phénoménes de Surface. Applications aux Oxydes et aux Silicates. Masson, Paris, 387 p.Google Scholar
Klobe, W.D. and Gast, R.G., (1970) Conditions affecting cesium retention and sodium entrapment in hydrobiotite and vermiculite Soil Science Society of America Proceedings 34 746–750 10.2136/sssaj1970.03615995003400050023x.CrossRefGoogle Scholar
Laperche, V., (1991) Etude de l’état et la localisation des cations compensateurs dans les phyllosilicates par des méthodes spectrométriques Paris, France Univ. Paris VII 100 p.Google Scholar
Le Dred, R. Saehr, D. and Baron, J., (1979) Préparation de vermiculite-interstratifiée-(Na,Rb) et-(Na,Cs) de type 1/1 par échange de cations Compte-Rendu de l’Academie des Sciences de Paris 289 47 50.Google Scholar
Martin de Vidales, J.-L. Vila, E. de La Ruiz-Amil, A. de La Calle, C. and Pons, C.-H., (1990) Interstratification in Malawi vermiculite: effect of bi-ionic K-Mg solutions Clays and Clay Minerals 38 513–521 10.1346/CCMN.1990.0380508.CrossRefGoogle Scholar
McCauley, J.M. and Newnham, R.E., (1971) Origin and prediction of ditrigonal distortions in micas American Mineralogist 56 1626 1638.Google Scholar
Rausell-Colom, J.A. Fernandez, M. Serratosa, J.M. Alcover, J.F. and Gatineau, L., (1980) Organisation de l’espace interlamellaire dans les vermiculites monocouches et anhydres Clay Minerals 15 37–58 10.1180/claymin.1980.015.1.04.CrossRefGoogle Scholar
Sawhney, B.L., (1969) Regularity of interstratification as affected by charge density in layer silicates Soil Science Society of America Proceedings 33 42–46 10.2136/sssaj1969.03615995003300010015x.CrossRefGoogle Scholar
Sawhney, B.L., (1972) Selective sorption and fixation of cations by clay minerals: a review Clays and Clay Minerals 20 93–100 10.1346/CCMN.1972.0200208.CrossRefGoogle Scholar
Schroeder, P.A., (1990) Far infrared, X-ray powder diffraction, and chemical investigation of potassium micas American Mineralogist 75 983 991.Google Scholar
Schroeder, P.A., (1992) Far infrared study of interlayer torsional vibrational mode of mixed-layer illite/smectite Clays and Clay Minerals 40 81–91 10.1346/CCMN.1992.0400109.CrossRefGoogle Scholar
Shannon, R.D., (1976) Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides Acta Crystallographica A32 751–767 10.1107/S0567739476001551.CrossRefGoogle Scholar
Shirozu, H. and Bailey, S.W., (1966) Crystal structure of a two layer Mg-vermiculite American Mineralogist 51 1124 1143.Google Scholar
Tateyama, H. Shimoda, S. and Sudo, T., (1977) Estimation of K-O distance and tetrahedral rotation angle of K-micas from far infrared absorption spectral data American Mineralogist 62 534 539.Google Scholar