ABSTRACT
Membranes are natural or artificial, two-dimensional objects, that separate fluids with different compositions from each other (Staude, 1992). Unlike boundary surfaces, the membrane forms its own phase (interphase). The special quality of membranes allows the transport of only specific matters or materials groups, called semipermeability (Ripperger, 1992). All species that are unable to permeate are rejected from the surface of the membrane. The transport of components through membranes is, therefore, selective. This process is summarized by the general term permeation. The capability of a membrane to allow the transport of gases and liquids is designated as permeability.
