Adsorption from solution and gas adsorption

Abstract

This chapter focuses on adsorption from solution and gas adsorption. An important step in the unification of theories of adsorption is that of establishing links, both theoretical and experimental, between the adsorption of single gases, mixed gases and the components of a liquid mixture. Purely thermodynamic arguments can establish general relationships between single gas and solution adsorption, but to derive detailed solution adsorption isotherms from gas adsorption data recourse must be had to theoretical models such as the surface phase model or the Polanyi potential theory. In their simplest forms, these are applicable only to ideal systems. Alternatively, solution adsorption may be regarded as the limit to which mixed gas adsorption tends as vapor saturation and bulk condensation conditions are approached. The chapter reviews these theoretical approaches and attempts to assess their relative merits and achievements in accounting for experimental observations. Attention is drawn to several important fundamental problems, and to the need for more accurate and extensive experimental data.