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Monolayer to Bilayer Transitional Arrangements of Hexadecyltrimethylammonium Cations on Na-Montmorillonite

Published online by Cambridge University Press:  01 January 2024

James L. Bonczek*
Affiliation:
Soil and Water Sciences Department, University of Florida, P.O. Box 110290, Gainesville, FL 32611-0151, USA
W. G. Harris
Affiliation:
Soil and Water Sciences Department, University of Florida, P.O. Box 110290, Gainesville, FL 32611-0151, USA
Peter Nkedi-Kizza
Affiliation:
Soil and Water Sciences Department, University of Florida, P.O. Box 110290, Gainesville, FL 32611-0151, USA
*
*E-mail address of corresponding author: bonczek@gnv.ifas.ufl.edu

Abstract

A low-charge Na-montmorillonite (SWy-2) was exchanged with hexadecyltrimethyl-ammonium (HDTMA) at levels equal to 20, 40, 60, 70, 80, 90, 100, 150 and 200% of the cation exchange capacity (819 mmol(+)/kg) to determine the nature of adsorption and the ionic composition of the clay interlayers. In contrast with earlier work with smaller aliphatic cations, which suggested random interstratification of interlayers occupied by either organic or metallic cations, there was no evidence of cation segregation into homogeneous interlayers. Instead, X-ray analysis indicated that the organic cations assumed two dominant configurations which were roughly equivalent in prevalence at ∼70% coverage of the CEC. Below 70% exchange the organocations existed predominantly in heterogeneous monolayers with Na+, attaining basal spacings of between 1.41 and 1.44 nm which were sensitive to changes in relative humidity. Relative humidity effects indicated that Na+ and HDTMA occupied functionally discrete domains within the interlayer as shown by the free interaction of water and a neutral organic solute, naphthalene, with Na+ and HDTMA, respectively. At greater levels of HDTMA exchange (up to 100% of the CEC), the organocations assumed a predominantly bilayer configuration. Transition to a fully-developed bilayer indicated by a 1.77 nm d-spacing at 100% coverage was gradual, suggesting some interstratification of the monolayers and bilayer configurations between 70 and 100% exchange. Sorption of naphthalene to the organoclays within this range of coverage was well correlated with clay organic carbon content, consistent with relatively unimpeded interlayer access of neutral organic molecules.

Type
Research Article
Copyright
Copyright © 2002, The Clay Minerals Society

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Footnotes

Florida Agricultural Experimental Station Journal Series No. R-08542

References

Boyd, S.A. Mortland, M.M. and Chiou, C.T., (1988) Sorption characteristics of organic compounds on hexadecyltrimethylammonium-smectite Soil Science Society of America Journal 52 652657 10.2136/sssaj1988.03615995005200030010x.Google Scholar
Harris, W.G. Hollien, K.A. Bates, S.R. and Acree, W.A., (1992) Dehydration of hydroxy-interlayered vermiculite as a function of time and temperature Clays and Clay Minerals 40 335340 10.1346/CCMN.1992.0400314.Google Scholar
Jaynes, W.F. and Boyd, S.A., (1990) Trimethylphenylammonium-smectite as an effective adsorbent of water soluble aromatic hydrocarbons Journal of Air Waste Management Association 40 16491653 10.1080/10473289.1990.10466811.Google Scholar
Jaynes, W.F. and Boyd, S.A., (1991) Clay mineral type and organic compound sorption by hexadecyltrimethylammonium-exchanged clays Soil Science Society of America Journal 55 4348 10.2136/sssaj1991.03615995005500010007x.Google Scholar
Laird, D.A. Scott, A.D. and Fenton, T.E., (1989) Evaluation of the alkylammonium method of determining layer charge Clays and Clay Minerals 37 4146 10.1346/CCMN.1989.0370105.Google Scholar
Lagaly, G., (1982) Layer charge heterogeneity in vermiculites Clays and Clay Minerals 30 215222 10.1346/CCMN.1982.0300308.Google Scholar
Lagaly, G. Fernandez Gonzalez, M. and Weiss, A., (1976) Problems in layer charge determination of montmorillonites Clay Minerals 11 173187 10.1180/claymin.1976.011.3.01.Google Scholar
Lee, J.F. Crum, J.R. and Boyd, S.A., (1989) Enhanced retention of organic compounds by soils exchanged with organic cations Environmental Science and Technology 23 13651372 10.1021/es00069a006.Google Scholar
McBride, M.B. and Mortland, M.M., (1975) Surface properties of mixed Cu(II)-tetraalkylammonium montmorillonites Clay Minerals 10 357368 10.1180/claymin.1975.010.5.03.Google Scholar
Mortland, M.M., (1970) Clay-organic complexes and interactions Advances in Agronomy 22 75117 10.1016/S0065-2113(08)60266-7.Google Scholar
Nzengung, V.A. Voudrias, E.A. Nkedi-Kizza, P. Wampler, J.M. and Weaver, C.E., (1996) Organic cosolvent effects on sorption equilibrium of hydrophobic organic chemicals by organoclays Environmental Science and Technology 30 8996 10.1021/es9501225.Google Scholar
Olis, A.C. Malla, P.B. and Douglas, L.A., (1990) The rapid estimation of the layer charges of 2:1 expanding clays from a single alkylammonium ion expansion Clay Minerals 25 3950 10.1180/claymin.1990.025.1.05.Google Scholar
Rytwo, G. Serban, C. Nir, S. and Margulies, L., (1991) Use of methylene blue and crystal violet for determination of exchangeable cations in montmorillonite Clays and Clay Minerals 39 551555 10.1346/CCMN.1991.0390510.Google Scholar
Sheng, G. Shihe, X. and Boyd, S.A., (1996) Mechanism(s) controlling sorption of neutral organic contaminants by surfactant-derived and natural organic matter Environmental Science and Technology 30 15531557 10.1021/es9505208.Google Scholar
Stul, M.S. and Mortier, W.J., (1974) The heterogeneity of charge density in montmorillonites Clays and Clay Minerals 22 391396 10.1346/CCMN.1974.0220505.Google Scholar
Theng, B.K.G. Greenland, D.J. and Quirk, J.P., (1967) Adsorption of alkylammonium cations by montmorillonite Clay Minerals 7 117 10.1180/claymin.1967.007.1.01.Google Scholar
Traina, S.J. and Onken, B.M., (1991) Cosorption of aromatic N-heterocycles and pyrene by smectites in aqueous solutions Journal of Contaminant Hydrology 7 237259 10.1016/0169-7722(91)90030-5.Google Scholar