Measurement and Analysis of Mixture Adsorption Equilibrium in Porous Solids

Most applications of adsorption involve fluid mixtures and porous solids. Three reference states with Gibbs definition of adsorption describe absolute, excess, and net adsorption frameworks. All depend on solid mass as the extensive property rather than surface area, an ambiguous concept for porous solids. Pure component isotherms by push-button apparatus are a first step to characterize adsorption, but process development also requires mixture data since models are not dependable. Mixture experiments are an order of magnitude more complicated than pure isotherms requiring careful design of apparatus and experiments. Thermodynamic relations are very useful for system and experimental design and for analysis of data. All relevant definitions and relations are explained in this paper and illustrated with a set of pure and binary mixture adsorption equilibrium data.