Ion-Exchange Membranes for Electrodialysis – A Patents Review

A review of patents published between 2005 and beginning of 2011 on organic ion-exchange membranes and electro-membrane processes is given. The electro-membrane processes include classical electrodialysis (ED), ED with a bipolar membrane, metathesis ED, electro-electrodialysis, and electrolysis. The applications of ion-exchange membranes are diverse and can be divided into the following groups: desalination and purification, removal of harmful substances, recovery of valuable substances, regeneration of spent solutions, production of new compounds. The patents on reversed ED for electric energy production are also surveyed. A large number of patents published indicates that the efficiency and environmental friendliness of electro-membrane processes are widely recognized. Keywords: Cation-exchange membrane, anion-exchange membrane, bipolar membrane, electrodialysis, electrolysis, desalination, regeneration, metathesis reaction