Calculation of the BET-Compatible Surface Area from Any Type I Isotherms Measured above the Critical Temperature.
In our previous papers [Tóth, J., et al., J. Colloid Interface Sci. 212, 402 (1999); 212, 411 (1999)] it has been proven that a BET-compatible specific surface area, a(s)(c)(N(2), 77), can be calculated from any Type I monolayer isotherms and from the monolayer domain of Type II isotherms, both measured below the critical temperature. In this paper, the calculation of a(s)(c)(N(2), 77) from Type I isotherms at temperatures above the critical temperature is discussed. These calculations are also based on the thermodynamical consistent form of the Tóth (T) equation. This relationship can be derived from the differential equation dn(s)/n(s)=[psi(p)](-1)dp/p, where the function psi(p) is calculable from the measured isotherms and includes the change in the surface free energy. The basic problem of the calculation of a(s)(c)(N(2), 77) is the determination of the upper limit of integration (p(u)) required to solve this differential equation. It is demonstrated that p(u) can be calculated from the equation ln(p(u))=-alphaT(-1)+beta. The constants alpha and beta are independent of the temperature of the isotherms but they are very sensitive to the structure of adsorbents and to the quality of adsorptives. This fact also makes it possible to characterize exactly the nanostructure of solids and the state of adsorptives. Copyright 2000 Academic Press.
Adsorption equilibrium data handbook
experimental data show that the adsorption of potassium on clinoptilolite after 7-hour at much higher rate in the presence of counter ions and equilibrium can be reached Fertilizers: Handbook, vilnius Pedagogical University. Press. For a feed concentration of 8.11 × 10−4 mol/l, Absorption and ion exchange perry's Valenzuela and Myers, Adsorption Equilibrium Data Handbook, Prentice. Description of equilibrium data of the adsorption of n-heptane on molecular sieve In R. D. Perry, & D. W. Green (Eds.), Perry's chemical engineers' handbook.
Adsorption of Freon 113
SummaryComparative adsorption data for Freon 113 (1,1,2 trichloro-1,2,2 trifluoroethane) and krypton on Graphon, presented in the preceding paper, showed that the adsorption behavior for krypton, measured at 104–120 K, and Freon 113, measured at 250–370 K, were very similar over the entire pressure range studied. The Freon 113 molecule was shown to adsorb with approximately 2.5 times the molecular area of krypton and to orient with its dipole axis perpendicular to the Graphon surface. Additional adsorption data gathered here indicate that the similar inert behavior of krypton and Freon 113 is also shown on heterogeneous energetic surfaces — anatase, silicon and water covered silica. Surface pressures (π) calculated for Freon 113 on surfaces exhibiting low heats of adsorption are approximately equal to the liquid surface tension, while for surfaces with high heats of adsorption, π can be twice as large.ZusammenfassungVergleichende Adsorptionsdaten von Freon 113 (1,1,2 Trichlor- 1,2,2 Trifluoräthan) und Krypton an Graphon zeigten ein sehr ähnliches Adsorptionsverhalten im gesamten untersuchten Druckbereich. Ein Freon 113-Molekül beansprucht etwa die 2 1/2-fache Fläche eines Krypton-Moleküls und orientiert sich mit seiner Dipolachse senkrecht zur Graphonoberfläche. Zusätzliche Adsorptionsdaten zeigen, daß das ähnliche Inertverhalten von Krypton und Freon 113 auch bei energetisch heterogenen Oberflächen wie Anatas, Silicium und wasserbedecktem Siliciumdioxid auftritt.