Statistically Modeled Adsorption Isotherms for the Multilayer Gas Molecules Adsorbed on Non-porous Solid Adsorbents of Two and Three Groups Sites

Daekyoum Kim

Korean Journal of Chemical Engineering, Vol.17, No.2, 156-168, March, 2000

Daekyoum Kim

Chem. Eng. Depart., Hanyang University, 17 Haengdang-dong, Sungdong-Ku, Seoul, Korea

The adsorption isotherms with each saturation vapor pressure factor (c_s1, c_s2 or c_s3) for two groups of sites in two cases of the multilayer and for three groups of sites in one case of the multilayer are derived statistically in heterogeneous non-porous solid adsorbents without interactions among the adsorbed molecules. When some sites of BET isotherm are substituted by less energetic sites, the two-group isotherm obtained by substitution, shows less adsorption over the whole range of relative pressure than the BET isotherm prior to the substitution, at any combined values of f₁ with M₁ of the two-group isotherm with the same saturation vapor pressure factor. A method to get the monolayer sites (v_m) from the ratios of the experimental isotherm to the theoretical isotherm at the whole relative vapor pressure minimizing the standard error is suggested. Our two-or three-group isotherms calculated through many experimental adsorption isotherm data selected appropriately provide larger values of v_m than those obtained from BET isotherm. Differential heat vs. v/v_m and Bose-Condensation heat are mentioned.

Keywords:Statistical Thermodynamics;Two-group Site Adsorption Isotherm;BET Isotherm

[References]

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Drain LE, Trans. Faraday Soc., 48, 840 (1952)
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Gerald P, J. Am. Chem. Soc., 67, 1958 (1945)
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Joyner LG, J. Am. Chem. Soc., 70, 2353 (1948)
Kim D, "Statistical Adsorption Isotherms on Heterogeneous Solid Adsorbent and Statistical Cation Distributions on Y Zeolites," Ph. D. Thesis, Seoul, Hanyang University (2000), expected
Knuth EL, "Perfect Diatomic Gas," introduction to STATISTICAL THERMODYNAMICS, McGraw Hill, Chapter 13 (1966)
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Loeser EH, J. Phys. Chem., 57, 591 (1953)
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[Referenced By]

[1] Adamson AW, "Adsorption of Gases and Vapors on Solids," Physical Chemistry of Surfaces, Chap. 16, John Wiley & Sons, Inc. 5th ed., 591 (1990)

[2] Anderson RB, J. Am. Chem. Soc., 68, 686 (1946)

[3] Brunauer S, J. Am. Chem. Soc., 62, 1723 (1940)

[4] Brunauer S, J. Am. Chem. Soc., 60, 309 (1938)

[5] Drain LE, Trans. Faraday Soc., 48, 840 (1952)

[6] Drain LE, Trans. Faraday Soc., 49, 654 (1953)

[7] Gerald P, J. Am. Chem. Soc., 67, 1958 (1945)

[8] Gregg SJ, "Physical Adsorption of Gases by Non-porous Solids," Chapter 2, Adsorption, Surface Area and Porosity, Academic Press Inc.(Ltd.) (1969)

[9] Hackerman N, J. Phys. Chem., 62, 1212 (1958)

[10] Harkins WD, J. Am. Chem. Soc., 66, 1362 (1944)

[11] Hill TL, J. Chem. Phys., 67, 1958 (1946)

[12] Hill TL, J. Chem. Phys., 17, 762 (1949)

[13] Hollaraugh CM, J. Phys. Chem., 65, 109 (1961)

[14] Isirikyan AA, J. Phys. Chem., 65, 601 (1961)

[15] Jaroniec M, "Physical Adsorption on Heterogeneous Solids," Elsevier, Amsterdam etc. (1988)

[16] Joyner LG, J. Am. Chem. Soc., 70, 2353 (1948)

[17] Kim D, "Statistical Adsorption Isotherms on Heterogeneous Solid Adsorbent and Statistical Cation Distributions on Y Zeolites," Ph. D. Thesis, Seoul, Hanyang University (2000), expected

[18] Knuth EL, "Perfect Diatomic Gas," introduction to STATISTICAL THERMODYNAMICS, McGraw Hill, Chapter 13 (1966)

[19] Langmuir, J. Am. Chem. Soc., 40, 1361 (1918)

[20] Loeser EH, J. Phys. Chem., 57, 591 (1953)

[21] McQuarrie DA, "Statistical Thermodynamics," Chap. 4, Harper & Row Publishers, 79 (1973)

[22] Rhodin TN, J. Am. Chem. Soc., 72, 4343 (1950)

[23] Rhodin TN, J. Phys. Chem., 57, 143 (1953)

[24] Rudizinski W, "Adsorption of Gases on Heterogeneous Surfaces," Academic Press, New York etc. (1992)

[25] Sears FW, "Statistical Thermodynamics," Thermodynamics, Kinetic Theory, and Statistical Thermodynamics, Chapter 11, Addison-Wesdey Publishing Company, 3rd ed., 302 (1975)

[26] Timmermann E, J. Chem. Soc. Faraday Trans. 1, 85(7), 1631 (1989)

[27] Tompkins FC, Trans. Faraday Soc., 46, 569 (1950)

[28] Van Dun JJ, J. Phys. Chem., 92, 6740 (1988)

[29] Van Dun JJ, J. Phys. Chem., 92, 6747 (1988)

[30] Zettlemoyer AC, J. Am. Chem. Soc., 72, 2752 (1950)