ABSTRACT
In this chapter an attempt is made to answer the question of why a limited number of materials were chosen for a certain membrane separation process, and to give a scientific guideline for the choice and the design of the membrane material. Materials used for the membrane cover a wide range, from organic polymeric materials to inorganic materials. Normally they are solid. Membranes are prepared from these materials and used for various separation processes, such as membrane gas separation, pervaporation, reverse osmosis, ultrafiltration, and microfiltration, depending on the pore size at the surface of the membrane. The solubility parameter is a parameter to express the nature and magnitude of the interaction force working between molecules. When applied to the membrane, the solubility parameter can give a measure to the interaction force working between the molecules that constitute the membrane material, and also the interaction force between the latter molecule and the permeant molecule.
