Ion exchange membranes containing inorganic particles

Abstract

This specification describes an ion exchange membrane and a method of making it. The membrane may be used, for example, in an electrodialysis module or electrochemical cell. The membrane comprises an ion exchange polymer and inorganic particles preferably linked to the ion exchange polymer. To make a membrane, inorganic particles are mixed into an ion exchange membrane pre-cursor. A polymerization initiator or catalyst is then added and the resulting mixture is placed in a form and cured. The inorganic particles may comprise, for example, an oxidized form of graphite such as graphite oxide. The ion exchange polymer may comprise an ionic monomer, containing a quaternary ammonium group for anion exchange or a sulfonate group for cation exchange, along with a crosslinking co-monomer containing polymerizable diacrylic functionalities. The membrane is self-supporting and can be made without a supporting fabric.

The invention claimed is: 
     
         1 . An ion exchange membrane comprising an ion exchange polymer and inorganic particles wherein the inorganic particles are linked to the ion exchange polymer. 
     
     
         2 . The ion exchange membrane of  claim 1  wherein the inorganic particles comprise graphite oxide, graphene oxide or partially reduced graphene oxide. 
     
     
         3 . The ion exchange membrane of  claim 1  wherein the ion exchange polymer comprises an ionic monomer containing a quaternary ammonium group or a sulfonate group along with a crosslinking co-monomer containing polymerizable diacrylic functionalities. 
     
     
         4 . The ion exchange membrane of  claim 1  without a supporting fabric. 
     
     
         5 . The ion exchange membrane of  claim 1  having a thickness of 0.1 to 0.4 mm. 
     
     
         6 . The ion exchange membrane of  claim 1  having a water content of 30-42%. 
     
     
         7 . The ion exchange membrane of any of  claim 1  having an ion exchange capacity of 1-2.4 meq/g. 
     
     
         8 . The ion exchange membrane of any of  claim 1  having a resistance of 5-15 Ohm-cm 2 .