Ion exchange membranes

Patent metadata

Field	Value
Publication number	US-9731247-B2
Application number	US-201514603115-A
Country	US
Kind code	B2
Filing date	Jan 22, 2015
Priority date	Aug 26, 2009
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

Highly energy efficient electrodialysis membranes having low operating costs and a novel process for their manufacture are described herein. The membranes are useful in the desalination of water and purification of waste water. They are effective in desalination of seawater due to their low electrical resistance and high permselectivity. These membranes are made by a novel process which results in membranes significantly thinner than prior art commercial electrodialysis membranes. The membranes are produced by polymerizing one or more monofunctional ionogenic monomers with at least one multifunctional monomer in the pores of a porous substrate.

First claim

What is claimed is:

1. An ion exchange membrane, comprising:
a microporous membrane support having a porous first side and a porous second side and a continuous porous structure comprising pores having a size of about 0.05 microns to about 10 microns extending from said first side to said second side; and
a crosslinked ion transferring polymer filling said porous structure, said polymer formed in the porous structure and comprising the polymerization product of at least one hydrophilic ionogenic monomer and a hydrophobic crosslinking monomer,
the ion exchange membrane having a permselectivity of greater than about 90%.

2. The ion exchange membrane of claim 1 , wherein the thickness of the porous support is greater than about 55 microns and less than about 155 microns.

3. The ion exchange membrane of claim 1 , wherein the thickness of the porous support is greater than about 20 microns and less than about 55 microns.

4. The ion exchange membrane of claim 1 , wherein the microporous support comprises polypropylene, high molecular weight polyethylene, ultrahigh molecular weight polyethylene or polyvinylidene fluoride.

5. The ion exchange membrane of claim 1 , wherein the ion transfer polymer is a cation transfer polymer and further comprises a a neutral monomer.

6. The ion exchange membrane of claim 5 , wherein the at least one hydrophilic ionogenic monomer is 2-sulfoethylmethacrylate (2-SEM or 2-acrylamide-2-methyl propane sulfonic acid (AMPS).

7. The ion exchange membrane of claim 6 , wherein the hydrophobic crosslinking monomer is ethyleneglycoldimethacrylate.

8. The membrane of claim 5 , wherein the neutral monomer is hydroxyethylacrylate or hydroxymethacrylate.

9. The cation exchange membrane of claim 5 , wherein the membrane has a resistivity not greater than about 0.5 Ohm-cm2.

10. The cation exchange membrane of claim 5 , wherein the membrane has a resistivity not greater than about 0.5 Ohm-cm2 and a permselectivity of greater than about 95%.

11. The cation exchange membrane of claim 5 , wherein the membrane has a resistivity not greater than about 0.5 Ohm-cm2 and a permselectivity of greater than about 99%.

12. The cation exchange membrane of claim 5 , wherein the membrane has a resistivity not greater than about 1.0 Ohm-cm2.

13. The cation exchange membrane of claim 5 , wherein the membrane has a resistivity not greater than about 1.0 Ohm-cm2 and a permselectivity of greater than about 95%.

14. The cation exchange membrane of claim 5 , wherein the membrane has a resistivity not greater than about 0.5 Ohm-cm2 and a permselectivity of greater than about 99%.

15. The ion exchange membrane of claim 1 , wherein the ion transfer polymer is an anion transfer polymer and further comprises a neutral monomer.

16. The anion exchange membrane of claim 15 , wherein the at least one hydrophilic ionogenic monomer is Trimethylammonium ethyl methacrylic chloride and the hydrophobic crosslinking monomer is ethylene glycol dimethacrylate.

17. The anion exchange membrane of claim 15 , wherein the at least one hydrophilic ionogenic monomer is Trimethylammonium ethyl methacrylic chloride and vinylbenzyl trimethylammonium chloride and the hydrophobic crosslinking monomer is divinylbenzene.

18. The anion exchange membrane of claim 17 , wherein the neutral monomer is hydroxyethylacrylate or hydroxymethacrylate.

19. The anion exchange membrane of claim 15 , wherein the membrane has a resistivity not greater than about 1.0 Ohm-cm2.

20. The anion exchange membrane of claim 15 , wherein the membrane has a resistivity not greater than about 1.0 Ohm-cm2 and a permselectivity of greater than about 94%.

21. The anion exchange membrane of claim 15 , wherein the membrane has a resistivity not greater than about 0.5 Ohm-cm2.

22. The anion exchange membrane of claim 15 , wherein the membrane has a resistivity not greater than about 0.5 Ohm-cm2 and a permselectivity of greater than about 94%.

23. The ion exchange membrane of claim 1 , wherein the continuous porous structure comprises pores having a size of about 0.1 microns to about 1.0 microns.

24. The ion exchange membrane of claim 23 , wherein the continuous porous structure comprises pores having a size of about 0.1 microns to about 0.2 microns.

25. The ion exchange membrane of claim 1 , wherein the microporous membrane support has a porosity of greater than about 45%.

26. The ion exchange membrane of claim 25 , wherein the microporous membrane support has a porosity of greater than about 60%.

Assignees

• Evoqua Water Tech Pte Ltd
• Evoqua Water Tech Llc

Inventors

• Lin Juchui Ray
• Gu George Y

Classifications

• B01D71/82

  characterised by the presence of specified groups, e.g. introduced by chemical after-treatment · CPC title

• C08J5/2225

  containing fluorine · CPC title

• C08J5/2275

  Heterogeneous membranes · CPC title

• B01D69/02

  characterised by their properties · CPC title

• B01D61/44 Primary

  Ion-selective electrodialysis · CPC title