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Hydrophobicity of Siloxane Surfaces in Smectites as Revealed by Aromatic Hydrocarbon Adsorption from Water

Published online by Cambridge University Press:  02 April 2024

W. F. Jaynes  and
S. A. Boyd
W. F. Jaynes
Affiliation:
Crop and Soil Science Department, Michigan State University, East Lansing, Michigan 48824
S. A. Boyd
Affiliation:
Crop and Soil Science Department, Michigan State University, East Lansing, Michigan 48824
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Abstract

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The nature of the siloxane surface in smectites was investigated by measuring the adsorption of aromatic hydrocarbons from water by organo-clays. The organo-clays were prepared by replacing the hydrophilic, inorganic exchange cations of a series of smectites with the small, hydrophobic organic cation, trimethylphenylammonium (TMPA). Smectites with a range in charge densities were used that resulted in different TMPA contents in the organo-clays. Adsorption isotherms of benzene, alkylbenzenes, and naphthalene from water by the TMPA-smectites indicated that sorption was inversely related to TMPA content. The Langmuir form of the isotherms suggests that the aromatic compounds adsorb to the clay surface. Possible adsorptive sites in TMPA-smectites are limited to the TMPA cations and the siloxane oxygen surfaces. Because sorption increased as layer charge and TMPA content decreased, the organic compounds must adsorb to the siloxane surfaces.

Calculations based on an adsorbed compound monolayer, which was estimated by fitting adsorption data to the Langmuir equation, and the N2 specific surface area of each TMPA-clay, indicate that the surface area occupied by each adsorbed molecule increases as the planar area of the molecule increases. This strongly indicates that the planar surfaces of the compounds adsorb directly to the clay surface. Apparently, the TMPA cations function to keep the smectite interlayers open. Interactions between the phenyl groups of TMPA cations on opposing interlayer clay surfaces may act to increase the size of the adsorptive regions. These results show that the siloxane surfaces of smectites can effectively adsorb aromatic hydrocarbons from water if the hydrophilic, inorganic exchange cations are replaced with small, hydrophobic organic cations. The strong adsorption of hydrophobic organic molecules from water demonstrates the hydrophobicity of the siloxane surfaces in smectites.

Keywords

Adsorption isothermAlkylbenzeneBenzeneLangmuir equationNaphthaleneOrganoclaySurface area
Type
Research Article
Information
Clays and Clay Minerals , Volume 39 , Issue 4 , August 1991 , pp. 428 - 436
Copyright
Copyright © 1991, The Clay Minerals Society

References

Barrer, R. M. and Perry, G. S., 1961 Sorption of mixtures, and selectivity in alkylammonium montmorillonites. Part II. Tetramethylammonium montmorillonite J. Chem. Soc. 850 – 858.CrossRefGoogle Scholar
Bleam, W. F., 1990 The nature of cation-substitution sites in phyllosilicates Clays & Clay Minerals 38 527 – 536.CrossRefGoogle Scholar
Bradley, W. F., 1945 Molecular associations between montmorillonite and organic liquids J. Am. Chem. Soc. 67 975 – 981.CrossRefGoogle Scholar
Brindley, G. W. and Ertem, G., 1971 Preparation and solvation properties of some variable charge montmorillonites Clays & Clay Minerals 19 399 – 404.CrossRefGoogle Scholar
Brunauer, S., Emmett, P. H. and Teller, E., 1938 Adsorption of gasses in multimolecular layers J. Amer. Chem. Soc. 60 309 – 319.CrossRefGoogle Scholar
Chen, N. Y., 1976 Hydrophobic properties of zeolites J. Phys. Chem. 80 60 – 64.CrossRefGoogle Scholar
Farmer, V.C. and Russell, J. D., 1971 Interlayer complexes in layer silicates. The structure of water in lamellar ionic solutions. Water on particle surfaces Trans. Faraday Soc. 67 2737 – 2749.CrossRefGoogle Scholar
Giles, C. H., MacEwan, T. H., Nakhwa, S. N. and Smith, D., 1960 Studies in adsorption. Part XI. A system of classification of solution adsorption isotherms, and its use in diagnosis of adsorption mechanisms and in measurement of specific surface areas of solids J. Chem. Soc 3973 – 3993.CrossRefGoogle Scholar
Graham, J., 1964 Adsorbed water on clays Rev. Pure and Appl. Chem. 14 81 – 90.Google Scholar
Gregg, S. J. and Sing, K. S. W., 1976 The adsorption of gases on porous solids Surface and Colloid Science 9 231 – 359.Google Scholar
Hendricks, S. B. and Jefferson, M. E., 1938 Structure of kaolin and talc-pyrophyllite hydrates and their bearing on water sorption of clays Am. Mineral. 23 863 – 875.Google Scholar
Hiemenz, P. C., 1986 Principles of Colloid and Surface Chemistry New York Marcel Dekker 398 – 407.Google Scholar
Hofmann, U. and Kiemen, R., 1950 Verlust der Austauschfähigkeit von Lithiumionen an Bentonit durch Efhitzung Z. Anorg. Allg. Chem. 262 95 – 99.CrossRefGoogle Scholar
Jaynes, W. F. and Bigham, J. M., 1987 Charge reduction, octahedral charge, and lithium retention in heated, Li-saturated smectites Clays & Clay Minerals 35 440 – 448.CrossRefGoogle Scholar
Jaynes, W. F. and Boyd, S. A., 1990 Trimethylphenylam-monium-smectite as an effective adsorbent of water soluble aromatic hydrocarbons J. Air Waste Mgmt. Assoc. 40 1649 – 1653.CrossRefGoogle ScholarPubMed
Jaynes, W. F. and Boyd, S. A., 1991 Clay mineral type and organic compound sorption by hexadecyltrimethylammo-nium-exchanged clays Soil Sci. Soc. Am. J. 55 43 – 48.CrossRefGoogle Scholar
Lee, J.-F. Mortland, M. M., Boyd, S. A. and Chiou, C. T., 1989 Shape-selective adsorption of aromatic compounds from water by tetramethylammonium-smectite J. Chem. Soc. Faraday Trans. I 85 2953 – 2962.CrossRefGoogle Scholar
Lee, J.-F. Mortland, M. M., Chiou, C. T., Kile, D. E. and Boyd, S. A., 1990 Adsorption of benzene, toluene, and xylene by two tetramethylammonium-smectites having different charge densities Clays & Clay Minerals 38 113 – 120.CrossRefGoogle Scholar
Low, P. F., 1961 Physical chemistry of clay-water interaction Adv. Agron. 13 269 – 327.CrossRefGoogle Scholar
MacEwan, D. M. C. Wilson, M. J., Brindley, G. W. and Brown, G., 1980 Interlayer and intercalation complexes of clay minerals Crystal Structures of Clay Minerals and Their X-ray Identification London Mineralogical Society 197 – 248.CrossRefGoogle Scholar
Rozenson, I. and Heller-Kallai, L., 1976 Reduction and oxidation of Fe3+ in dioctahedral smectites—1. Reduction with hydrazine and dithionite Clays & Clay Minerals 24 271 – 282.CrossRefGoogle Scholar
Skipper, N. T., Refson, K. and McConnell, J. D. C., 1989 Computer calculation of water-clay interactions using atomic pair potentials Clay Miner. 24 411 – 425.CrossRefGoogle Scholar
Sposito, G., 1984 The Surface Chemistry of Soils. Oxford Oxford University Press.Google Scholar
Sposito, G. and Prost, R., 1982 Structure of water adsorbed on smectites Chem. Rev. 82 553 – 573.CrossRefGoogle Scholar
Steel, R. G. and Torrie, J. H., 1980 Principles and Procedures of Statistics. A Biometrical Approach 2nd New York McGraw-Hill 239 – 271.Google Scholar
van Olphen, H. and Fripiat, J. J., 1979 Data Handbook for Clay Materials and Other Non-metallic Minerals Oxford Pergamon Press 203 – 216.Google Scholar