Mass-transfer membrane and processes using same
First Claim
1. In an electrochemical process wherein ions in one body of liquid pass through an operative portion of an ion-permeable membrane assembly into another body of liquid, the improvement which comprises using an ion-permeable membrane assembly which comprises(a) a film of electrically insulating material, wherein said film is substantially impermeable to water, is substantially ion-impermeable and has a thickness of 1 micron to 1 millimeter;
- (b) and at least one layer of porous material disposed on at least one surface of said film wherein the layer of porous material has a thickness which ranges from 0.01 to 1.0 millimeters, and wherein the thickness of said layer is greater than the average pore size of the pores of said porous material and wherein the material of said porous layer is incapable of acting as an electrode,wherein each of said film and said porous material is substantially chemically inert under the conditions existing in the cell.
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Accused Products
Abstract
A porous layer is provided on one or both surfaces of a mass-transfer membrane to enhance or modify the passage of ions. The membrane may be a film of any of a variety of polymeric materials, and the porous layer may be a surface layer on the membrane or a separate porous structure placed in contact therewith. The porous layer or layers render certain normally ion-impermeable polymeric films capable of passing ions in an electrodialysis-type system.
43 Citations
27 Claims
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1. In an electrochemical process wherein ions in one body of liquid pass through an operative portion of an ion-permeable membrane assembly into another body of liquid, the improvement which comprises using an ion-permeable membrane assembly which comprises
(a) a film of electrically insulating material, wherein said film is substantially impermeable to water, is substantially ion-impermeable and has a thickness of 1 micron to 1 millimeter; (b) and at least one layer of porous material disposed on at least one surface of said film wherein the layer of porous material has a thickness which ranges from 0.01 to 1.0 millimeters, and wherein the thickness of said layer is greater than the average pore size of the pores of said porous material and wherein the material of said porous layer is incapable of acting as an electrode, wherein each of said film and said porous material is substantially chemically inert under the conditions existing in the cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 16)
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9. In an electrochemical cell which comprises at least two compartments, said compartments being separated by an ion-permeable membrane assembly, wherein said membrane assembly comprises
(a) a film of electrically insulating material, wherein said film is substantially impermeable to water, is substantially ion-impermeable and has a thickness of 1 micron to 1 millimeter; (b) and at least one layer of porous material disposed on at least one surface of said film wherein the layer of porous material has a thickness which ranges from 0.01 to 1.0 millimeters and wherein the thickness of said layer is greater than the average pore size of the pores of said porous material and wherein the material of said porous layer is incapable of acting as an electrode, wherein each of said film and said porous material is substantially chemically inert under the conditions existing in the cell. - View Dependent Claims (10, 11, 12, 13, 14, 15, 17)
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18. A membrane assembly, which divides an electrochemical cell into at least two compartments comprising
(a) a film of substantially electrically insulating material, wherein said film is substantially impermeable to water, is substantially ion-impermeable and has a thickness of 1 micron to 1 millimeter; (b) and at least one layer of porous material disposed on at least one surface of said film, wherein said layer of porous material has a thickness which ranges from 0.01 to 1.0 millimeters, and wherein the thickness of said layer is greater than the average pore size of the pores of said porous material and wherein the material of said porous layer is incapable of acting as an electrode, wherein each of said film and said porous material is substantially chemically inert under the conditions existing in the cell. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
Specification