Clays and Clay Minerals

, Volume 8, Issue 1, pp 84–101 | Cite as

Thermodynamics of Water Adsorption and Desorption on Montmorillonite

  • Isaac Barshad


Methods are presented for determining partial and integral thermodynamic quantities for the change in state of water and clay during the course of their interaction. The quantities determined are: free energy, heat and entropy changes. The effect on the magnitude of these quantities of the nature and amount of the exchangeable cations is reported. It is concluded that the magnitude of change in the thermodynamic quantities due to moving the exchangeable cations out of the hexagonal cavities in the oxygen sheets is considerably greater than that due to the parting of the oxygen sheets during the interlayer expansion.


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  1. Barshad, Isaac (1949) The nature of lattice expansion and its relation to hydration in montmorillonite and vermiculite: Amer. Min., v. 34, pp. 675–684.Google Scholar
  2. Barshad, Isaac (1952) Factors affecting the interlayer expansion of vermiculite and montmorillonite with organic substances: Soil Sci. Soc. Amer., Proc., v. 16, pp. 176–182.CrossRefGoogle Scholar
  3. Barshad, Isaac (1952a) Temperature and heat of reaction calibration of the differential thermal analysis apparatus: Amer. Min., v. 37, pp. 667–694.Google Scholar
  4. Barshad, Isaac (1955) Adsorptive and swelling properties of clay-water system: in Clays and Clay Technology, California Div. of Mines, Bull. 169, pp. 70–77.Google Scholar
  5. Lewis, G. H. and Bandall, M. (1923) Thermodynamics and the Free Energy of Chemical Substances: McGraw-Hill Book Co., Inc., New York.Google Scholar

Copyright information

© The Clay Minerals Society 1959

Authors and Affiliations

  • Isaac Barshad
    • 1
  1. 1.University of CaliforniaBerkeleyUSA

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