Analysis of Gas and Vapor Sorption in Polymer Membranes of Interest for Gas Separation (Including Ionic Liquids)
This chapter is designated for anybody, who is interested in the gas and vapour sorption in polymers intended for membrane separation processes. The importance and advantages of the membrane separation processes have been recognized during the last decades, during which membrane separation has grown into a widely used separation technology. The elucidation of the cause and effect relationship in membrane fabrication/morphology/performance represents the necessary component of membrane research and development. In this context, equilibrium sorption of low molecular weight compounds in polymer materials is an essential characteristic for the assessment of the interactions between penetrant and polymer membrane. An extension of membrane application possibilities raises the need of a thorough knowledge of material properties. By knowing them, membrane users are then able to choose conveniently those membranes that satisfy their requirements and to decide the optimal conditions for their use. In this chapter, we discuss the equilibrium sorption process, sorption isotherms and models with a functional dependency which explicitly or implicitly expresses the dependence of activity on the concentration of sorbate (low molecular weight compound) in various kinds of sorbents, mainly in dense polymers. Next to that, we provide a brief tour on experimental determination of sorption accompanied with examples of real sorption characteristics.