Abstract
Functional membranes are currently employed in a broad range of aplications. Among these membranes, the ion exchange membranes have special functional charcteristics such as permselectivities for specific ions, a low permeability for water, and/or permselectivities for inorganic ions and organic molecules. The selective transport of cations or anions through the membrane is provided by the ion exchange body in membrane form; an increase in fixed-ion concentration gives a higher membrane performance. Membranes, possessing a high permselectivity for univalent ions, are obtamable by the formation of a charged thin-layer on the membrane surface : The charge of the thin-layer is opposite to that of the rest part of the membrane. Permselectivities for inorganic ions and organic molecules are provided by a fine-pore structure of the membrane and the capability for ion transports.
