Polymer based permeable membrane for removal of ions

• US 20030113234A1
• Filed: 10/16/2002
• Published: 06/19/2003
• Est. Priority Date: 10/16/2001
• Status: Active Grant

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Murray, George M.
• Granted Patent: US 6,780,323 B2
• Time in Patent Office: Days
• US Class Current: 422/101
• CPC Class Codes: B01D 2323/18 Pore-control agents or pore formers
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 2325/04 Characteristic thickness
• CPC Class Codes: B01D 2325/14 Membrane materials having negatively charged functional groups
• CPC Class Codes: B01D 2325/16 Membrane materials having positively charged functional groups
• CPC Class Codes: B01D 2325/20 Specific permeability or cut-off range
• CPC Class Codes: B01D 61/00 Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor separation of gases or vapours by diffusion B01D53/22
• CPC Class Codes: B01D 61/002 Forward osmosis or direct osmosis
• CPC Class Codes: B01D 61/005 Osmotic agents; Draw solutions
• CPC Class Codes: B01D 67/0006 by chemical reactions in-situ polymerisation, polycondensation, cross-linking or reaction for manufacturing composite membranes B01D69/125
• CPC Class Codes: B01D 67/003 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 71/28 Polymers of vinyl aromatic compounds
• CPC Class Codes: B01D 71/281 Polystyrene
• CPC Class Codes: B01J 20/26 Synthetic macromolecular compounds
• CPC Class Codes: B01J 20/261 obtained by reactions only involving carbon to carbon unsaturated bonds macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds per se C08F
• CPC Class Codes: B01J 20/267 Cross-linked polymers
• CPC Class Codes: B01J 20/268 Polymers created by use of a template, e.g. molecularly imprinted polymers
• CPC Class Codes: B01J 20/28033 Membrane, sheet, cloth, pad, lamellar or mat
• CPC Class Codes: B01J 20/3057 Use of a templating or imprinting material molecularly imprinted polymers B01J20/268; filling pores of a substrate or matrix followed by the removal of the substrate or matrix
• CPC Class Codes: B01J 45/00 : Ion-exchange in which a complex or a chelate is formed; Use of material as complex or chelate forming ion-exchangers; Treatment of material for improving the complex or chelate forming ion-exchange properties ion-exchange chromatography processes B01D15/36
• CPC Class Codes: B01J 47/12 : characterised by the use of ion-exchange material in the form of ribbons, filaments, fibres or sheets, e.g. membranes electrodialysis or electro-osmosis B01D61/42
• CPC Class Codes: C02F 1/285 : using synthetic organic sorbents
• CPC Class Codes: C02F 1/44 : by dialysis, osmosis or reverse osmosis general membrane separation processes B01D61/00, membrane modules B01D63/00, electrodialysis C02F1/4693, combination of membrane modules and bioreactors C02F3/1268
• CPC Class Codes: C02F 2101/105 : Phosphorus compounds
• CPC Class Codes: C02F 2101/163 : Nitrates
• CPC Class Codes: C02F 2101/203 : Iron or iron compound
• CPC Class Codes: Y10T 436/25 : including sample preparation

Abstract

Molecularly imprinted polymer membranes for selectively collecting phosphate, nitrate and ferric ions are disclosed, prepared by copolymerizing a matrix monomer, cross-linking agent, ion imprinting complex, permeability agent and polymerization initiator, after which the ions of the ion imprinting complex are permeability agent are removed. The permeability agent creates channels in the membrane permitting the ion binding sites in the membrane to communicate with the exterior surface of the membrane.

Claims

1. A method for making a molecularly imprinted polymer membrane including a selective binding site for phosphate anions, comprising the steps of:

copolymerizing a polymerization mixture comprising a matrix monomer, a cross-linking agent, a lanthanide-phosphate anion imprinting complex, a permeability agent, and an initiator for said polymerization mixture, so that a polymer membrane is formed; and

removing phosphate anions and said permeability agent from said polymer membrane so that channels and cavities for receiving phosphate anions are formed in said membrane, wherein said cavities are in communication with the exterior surface of said membrane by means of said channels.

2. The method according to claim 1, wherein said matrix monomer is styrene.

3. The method according to claim 1, wherein said cross-linking agent is divinylbenzene.

4. The method according to claim 1, wherein said lanthanide-phosphate anion imprinting complex is Lanthanide (III) tris-(vinylbenzoylacetonate) (acryamidophenanthroline)phosphate.

5. The method according to claim 1, wherein said permeability agent is polyester.

6. The method according to claim 1, wherein said initiator is azobisisobutyronitrile.

7. The method according to claim 1, wherein said removing step comprises the step of subjecting said polymer membrane to an acidic solution.

31. A molecularly imprinted polymer membrane prepared according to the process of claim 1.

34. The membrane according to claim 31, further comprising phosphate anions bound thereon.

37. A method for removing phosphate anions from an aqueous solution, ion, comprising the step of:

passing against an anion counterflow a solution containing phosphate anions through a membrane prepared according to the process of claim 1.

39. The method according to claim 37, further comprising the step of collecting the anions.

8. A method for making a molecularly imprinted polymer membrane including a selective binding site for nitrate anions, comprising the steps of:

copolymerizing a polymerization mixture comprising a matrix monomer, a cross-linking agent, a nickel-nitrate anion imprinting complex, a permeability agent, and an initiator for said polymerization mixture, so that a polymer membrane is formed; and

removing nitrate anions and said permeability agent from said polymer membrane so that cavities and channels for receiving nitrate anions are formed in said membrane, wherein said cavities are in communication with the exterior surface of said membrane by means of said channels.

9. The method according to claim 8, wherein said matrix monomer is styrene.

10. The method according to claim 8, wherein said cross-linking agent is divinylbenzene.

11. The method according to claim 8, wherein said nickel-nitrate anion imprinting complex is Ni (II)(bis-acrylamidophenanthroline)nitrate.

12. The method according to claim 8, wherein said permeability agent is polyester.

13. The method according to claim 8, wherein said initiator is azobisisobutyronitrile.

14. The method according to claim 8, wherein said removing step comprises the step of subjecting said polymer membrane to an acidic solution.

32. A molecularly imprinted polymer membrane prepared according to the process of claim 8.

35. The membrane according to claim 32, further comprising nitrate anions bound thereon.

40. A method for removing nitrate anions from an aqueous solution, comprising the step of:

passing against an anion counterflow a solution containing nitrate anions through a membrane prepared according to the process of claim 8.

41. The method according to claim 40, further comprising the step of collecting the anions.

15. A method for making a molecularly imprinted polymer membrane including a selective binding site for ferric cations, comprising the steps of:

copolymerizing a polymerization mixture comprising a matrix monomer, a cross-linking agent, a iron (III) tris-vinylbenzoate cation imprinting complex, a permeability agent, and an initiator for said polymerization mixture, so that a polymer membrane is formed; and

removing iron(III) and said permeability agent from said polymer membrane so that cavities and channels for receiving ferric cations are formed in said membrane, wherein said cavities are in communication with the exterior surface of said membrane by means of said channels.

16. The method according to claim 15, wherein said matrix monomer is styrene.

17. The method according to claim 15, wherein said cross-linking agent is divinylbenzene.

18. The method according to claim 15, wherein said iron vinylbenzoate cation imprinting complex is Fe(vinylbenzoate)₃.

19. The method according to claim 15, wherein said permeability agent is polyester.

20. The method according to claim 15, wherein said initiator is azobisisobutyronitrile.

21. The method according to claim 15, wherein said removing step comprises the step of subjecting said polymer membrane to an acidic solution.

33. A molecularly imprinted polymer membrane prepared according to the process of claim 15.

36. The membrane according to claim 33, further comprising ferric cations bound thereon.

42. A method for removing ferric cations from an aqueous solution, comprising the step of:

passing against an anion counterflow a solution containing ferric cations through a membrane prepared according to the process of claim 15.

43. The method according to claim 42, further comprising the step of collecting the cations.

22. A molecularly imprinted polymer membrane comprising a cross-linked polymer matrix having channels disposed therethrough, and with selective binding sites for phosphate anions on the interior thereof in communication with the exterior surface of said membrane by means of said channels, which thereby increase permeability and direct said phosphate anions to said binding sites.

23. The membrane according to claim 22, having a thickness of approximately 100 microns.

24. The membrane according to claim 23, wherein said matrix polymer is polystyrene cross-lined with divinylbenzene.

25. A molecularly imprinted polymer membrane comprising a cross-linked polymer matrix having channels disposed therethrough and with selective binding sites for nitrate anions on the interior thereof in communication with the exterior surface of said membrane by means of said channels, which thereby increase permeability and direct said nitrate anions to said binding sites.

26. The membrane according to claim 25, having a thickness of approximately 100 microns.

27. The membrane according to claim 26, wherein said matrix polymer is polystyrene cross-linked with divinylbenzene.

28. A molecularly imprinted polymer membrane comprising a cross-linked polymer matrix having channels disposed therethrough and with selective binding sites for ferric cations on the interior thereof in communication with the exterior surface of said membrane by means of said channels, which thereby increase permeability and direct said ferric cations to said binding sites.

29. The membrane according to claim 28, having a thickness of approximately 100 microns.

30. The membrane according to claim 28, wherein said matrix polymer is polystyrene cross-linked with divinylbenzene.