Multiphase ideal adsorbed solution

Ideal adsorbed solution Activity coefficient / = 1 Ideal adsorbed solution theory (lAST) Multiphase ideal adsorbed solution theory (MIAST) Heterogeneous ideal adsorbed solution theory (HIAST)... [Pg.95]

The multiphase ideal adsorbed solution theory (MIAST) is another model of the family of adsorbed solutions. Corrtraiy to HAST, an energy distribution function is assumed with differences of the local or molectrlar site energy. Therefore, every site has its own local adsorption isotherm arrd the adsorbate concentration differs from site to site. The adsorbate is not considered as a homogeneous phase but as a multiphase system. [Pg.99]

Fundamental studies on the adsorption of supercritical fluids at the gas-solid interface are rarely cited in the supercritical fluid extraction literature. This is most unfortunate since equilibrium shifts induced by gas phase non-ideality in multiphase systems can rarely be totally attributed to solute solubility in the supercritical fluid phase. The partitioning of an adsorbed specie between the interface and gaseous phase can be governed by a complex array of molecular interactions which depend on the relative intensity of the adsorbate-adsorbent interactions, adsorbate-adsorbate association, the sorption of the supercritical fluid at the solid interface, and the solubility of the sorbate in the critical fluid. As we shall demonstrate, competitive adsorption between the sorbate and the supercritical fluid at the gas-solid interface is a significant mechanism which should be considered in the proper design of adsorption/desorption methods which incorporate dense gases as one of the active phases. [Pg.152]