Exchange Membrane Materials and Structures

Many of today s available membranes meet most of these requirements. In particular, the Nafion-type cation-exchange membrane has quite satisfactory properties for applications in the chlorine-alkaline electrolyses as well as in electrodialysis [6], Anion-exchange membranes often show lower stability in strong alkaline solutions than cation-exchange membranes. 

The following moieties are used as fixed charges in cation-exchange membranes  

Ion-exchange membranes can also be divided, according to their structure and preparation procedure, into homogeneous and heterogeneous membranes [4]. 

In homogeneous ion-exchange membranes the fixed-charged groups are evenly distributed over the entire membrane polymer matrix. Homogeneous membranes can be produced, for example, by polymerization or polycondensation of functional monomers such as phenolsulfonic acid, or by functionalizing a polymer such as polysulfone dissolved in an appropriate solvent by sulfonation. 

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