Nonideal Adsorption Equilibria Described by Pure Component Isotherms and Virial Mixture Coefficients

Abstract

A novel method is used to describe adsorption equilibria of nonideal mixtures. The two-dimensional virial equation of state is reorganized so that contributions of single components are separated from those of mixed components. Existing single component adsorption isotherm equations, which describe pure component data better and with fewer parameters than a truncated virial series, are substituted for the pure component terms. The remaining equation of state then contains terms corresponding to the pure component isotherms and terms with virial cross-coefficients for the mixture. The method is applied first to a mixture of Langmuirian adsorbates to demonstrate a sound thermodynamic and mathematical basis. We then consider nonideal binary and ternary mixtures of carbon dioxide, hydrogen sulfide, and propane on H-mordenite and a highly nonideal mixture of n-hexane and water on activated carbon.

Cooperative adsorption on solid surfaces

“…More complicated liquid solution theories have been applied to extend or modify the IAST model. The non-ideal adsorbed solution theory is thus in order [23][24][25]. Along the line of adsorbed solution theories, the potential theory of adsorption regard the mixture as a heterogeneous substance segregated in the external field emitted by the adsorbent [26][27][28][29].…”

Gas adsorption separation of CO2/CH4 system using zeolite 5A

“…They used Virial equation of state and calculated the fugacity in a two-dimensional adsorbed mixture by the equation previously proposed by Hoory and Prausnitz [22]. They used the experimental activity coefficients measured by Talu and Zwiebel [16] for binary mixtures of C 3 H 8 and H 2 S. In the preceding years two-dimensional equations of state have been used to correlate or predict pure and multi-component gas adsorption equilibria utilizing some empirical mixing rules [23,24,25].…”

A mathematical model for competitive adsorptions

“…More complicated liquid solution theories have been applied to extend or modify the IAST model. The non-ideal adsorbed solution theory is thus in order [22][23][24]. Along the line of adsorbed solution theories, the potential theory of adsorption regard the mixture as a heterogeneous substance segregated in the external field emitted by the adsorbent [25][26][27][28].…”