Volmer

150

ADSORPTION

Vol. 1

/,    At

Fig. 5. Explanation of one step of pore-size measurement by adsorptive method. This figurę is available in fuli color at http://w\vw.mrw.interscience.wiley.com/encaat/.

For smali pores where the Kelvin eąuation is not valid, the “molecular probe method” is sometimes used. At nearly saturated pressure of different liąuids (p/po = 0.7-0.9), some points of pore-size distribution can be obtained with the help of the adsorbed amounts.

Thus, when correct energy parameters on a molecular level are known and adeąuate geometrical models for micropore filling are used, the pore-size distribution can be calculated (23):

RT ln(/Vp0) = K(U0 ■+ Pa) = KWI)	(22)
p/porr = f(w/wo)	(23)

BIBLIOGRAPHY

1.    F. Rouąuerol, J. Rouqucrol, and K. Sing, Adsorpłion by Powders and Porous Solids, Academic Press, Inc., New York, 1999, pp. 10 and 27.

2.    Ref. 1, p. 439.

3.    H. H. Rowley and W. B. Innes, J. Phys. Chem. 45, 158 (1941).

4.    P. H. Emmett and S. Brunauer, J. Am. Chem. Soc. 56, 35 (1937).

5.    P. H. Emmett, Adu. Colloid Sci. 1, 3 (1942).

6.    M. Suzuki, Adsorption Engineering, Elsevier, Amsterdam, 1990, pp. 22.

7.    Ref. 6, p. 67.

8.    D. H. Everett, Pure Appl. Chem. 58, 967 (1986).

9.    L. Langmuir, J. Amer. Chem. Soc. 38, 2221 (1916).

10.    L. Langmuir, J. Amer. Chem. Soc. 40, 1361 (1916).

11.    M. Volmer, Z. Phys. Sche. 40, 253 (1925).

12.    J. H. de Boer, The Dynamical Character of Adsorption, Oxford University Press, London, 1968, p. 169.

13.    S. Brunauer, P. H. Emmett, and E. Teller, J. Am. Chem. Soc. 60. 309 (1941).