Graphene membrane and method for making graphene membrane

Abstract

A membrane includes a substrate having pores therethrough, and a first layer of graphene platelets supported by the substrate. The graphene platelets of the first layer at least partially fill the pores of the substrate.

We claim: 
     
         1 . A membrane comprising:
 a substrate having pores therethrough;   a first layer of graphene platelets supported by the substrate, wherein the graphene platelets of the first layer at least partially fill the pores of the substrate.   
     
     
         2 . The membrane of  claim 1 , wherein the graphene platelets of the first layer are spaced apart to allow passage of a filtrate therebetween. 
     
     
         3 . The membrane of  claim 1 , further comprising a second layer of graphene platelets supported by the substrate and covering the first layer. 
     
     
         4 . The membrane of  claim 3 , further comprising a third layer of graphene platelets supported by the substrate and covering the second layer. 
     
     
         5 . The membrane of  claim 4 , wherein the graphene platelets of the first layer and the graphene platelets of the third layer are hydrophobic, and the graphene platelets of the second layer are hydrophilic. 
     
     
         6 . The membrane of  claim 4 , wherein the graphene platelets of the first layer and the graphene platelets of the third layer comprise aminated graphene platelets, and the graphene platelets of the second layer comprise hydroxylated graphene platelets 
     
     
         7 . The membrane of  claim 3 , wherein the graphene platelets of the first layer and/or the graphene platelets of the second layer are functionalized. 
     
     
         8 . The membrane of  claim 1 , wherein the graphene platelets of the first layer are hydrophobic. 
     
     
         9 . The membrane of  claim 8 , further comprising a second layer of graphene platelets supported by the substrate and covering the first layer, wherein the graphene platelets of the second layer are hydrophilic. 
     
     
         10 . The membrane of  claim 1 , wherein the graphene platelets of the first layer comprise aminated graphene platelets. 
     
     
         11 . The membrane of  claim 10 , further comprising a second layer of graphene platelets supported by the substrate and covering the first layer, wherein the graphene platelets of the second layer comprise hydroxylated graphene platelets. 
     
     
         12 . The membrane of  claim 1 , wherein the polymer substrate carries a first electrostatic charge. 
     
     
         13 . The membrane of  claim 12 , wherein the graphene platelets of the first layer carry a second electrostatic charge that is opposite the first electrostatic charge. 
     
     
         14 . The membrane of  claim 13 , further comprising a second layer of graphene platelets supported by the substrate and covering the first layer, wherein the graphene platelets of the second layer carry a third electrostatic charge that is opposite the second electrostatic charge. 
     
     
         15 . The membrane of  claim 1 , wherein the graphene platelets of the first layer have a diameter of at most 100 microns. 
     
     
         16 . The membrane of  claim 14 , wherein the graphene platelets of the first layer include between 1 and 9 sheets of graphene. 
     
     
         17 . The membrane of  claim 15 , wherein the graphene platelets of the first layer have a thickness of at most 15 nm. 
     
     
         18 . The membrane of  claim 1 , wherein the substrate comprises a polymer. 
     
     
         19 . The membrane of  claim 1 , wherein the pores have a pore size of less than 0.03 microns. 
     
     
         20 . The membrane of  claim 1 , wherein the substrate is an acid-treated polysulfone.