Multimodel approach to mixed‐gas adsorption equilibria prediction

A thermodynamically consistent, multimodel approach for the prediction of mixture adsorption equilibria from pure‐component adsorption isotherms is described. The ideal adsorbed solution (IAS) model is employed at low surface coverage, where potential attractive forces tend to govern adsorption behavior. An energetically quasi‐homogeneous version of the Langmuir‐Freundlich (LF) model is proposed at high coverage, where lateral adsorbate interactions and finite‐adsorbent geometric constraints tend to homogenize such attractive forces. The classical LF model is used for intermediate coverage, where both energetic attractive and geometric constraining forces contribute significantly to mixed‐gas adsorption behavior. A major benefit of this three‐regime modeling method is that physically realistic adsorptive selectivities can be adhered to at both extremes of coverage, a property not generally shared by either the IAS or LF models taken singly. This three‐regime approach yields better multicomponent equilibria predictions than IAS‐only modeling approaches for many relatively nonideal adsorption systems.