Towards a general gas adsorption isotherm

Determination of Azeotropic Behavior in Adsorbed Mixtures

“…The multisite Langmuir model, as well as other extensions of the Langmuir model are able to produce azeotropic behavior for mixtures of adsorbates of different size, and at pressures above the crossing point of the pure component isotherms (Sircar, 1995;Martinez and Basmadjian, 1996;Bai and Yang, 2001). At pressures much higher than the point where isotherms cross, complete reversal in selectivity over the whole range of compositions can be observed.…”

Equilibrium and kinetics ofn– hexane sorption in pellets of 5A zeolite

“…Sorption isotherms in molecular-sieve zeolites are generally type I in IUPAC classification. These isotherms can be interpreted by thermodynamic analysis using virial isotherms (e.g., Kiselev, 1971;Doetsh et al, 1974;Barrer, 1981;Ruthven and Kaul, 1996), by molecular models based on localized adsorption (e.g., Langmuir, 1918;Nitta et al, 1984;Martinez and Basmadjian, 1996), and using the potential theory (e.g., Dubinin's volume-filling theory, 1975). Zeolite molecular sieves consist of small microporous crystals formed in a macroporous pellet; kinetics of sorption in these adsorbents generally offers two distinct resistances to mass transfer: the macroporous resistance of the pellet and the microporous resistance of the crystals.…”

Statistical Thermodynamics of Lattice Gas Models of Multisite Adsorption

“…The model can be formulate by following: the molecule can be adsorbed on the surface by the k ways occupying the 12 As it noted in [90], the results obtained for adsorption of complex molecules can be extended also to the gas mixtures. In other words, the general model can be considered as a special case of gas mixtures adsorption model.…”

“…The necessity of describing of the n-alkane adsorption in the framework of the models with multisite adsorption is also supported by the fact that at the interpretation of experimental adsorption isotherms by using the known multisite Langmuir model and other analytical models there exists good correlation between the model parameter k (the number of active sites occupied by adsorbate molecule) and the real number of segments in the molecule of the adsorbate [7,8,[10][11][12]. It should be noted that the above analytical models of multisite adsorption are used to determine the specific surface of porous solids and its topography (in the case of energetically heterogeneous surfaces).…”