MICROPOROUS FILTER MEDIA, FILTRATION SYSTEMS CONTAINING SAME, AND METHODS OF MAKING AND USING

• US 20030140785A1
• Filed: 11/08/2002
• Published: 07/31/2003
• Est. Priority Date: 01/31/2002
• Status: Active Grant

• Current Assignee: KX Technologies, LLC (Berkshire Hathaway Incorporated)
• Original Assignee: Koslow Tech Corp
• Inventors: Koslow, Evan E.
• Granted Patent: US 6,630,016 B2
• Time in Patent Office: Days
• US Class Current: 95/90
• CPC Class Codes: A61L 2/0017 Filtration
• CPC Class Codes: A61L 2/0082 using chemical substances
• CPC Class Codes: A61L 2/022 Filtration
• CPC Class Codes: A61L 9/16 using physical phenomena
• CPC Class Codes: B01D 2201/34 Seals or gaskets for filtering elements for removable closures, lids, caps or filter heads B01D2201/304
• CPC Class Codes: B01D 29/15 arranged for inward flow filtration
• CPC Class Codes: B01D 29/41 mounted transversely on the tube
• CPC Class Codes: B01D 37/02 Precoating the filter medium; Addition of filter aids to the liquid being filtered devices for feeding reagents C02F1/685 and sub-groups; filter aids
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: B01D 39/18 the material being cellulose or derivatives thereof cork or peat B01D39/1646 ; making filter paper D21F11/14
• CPC Class Codes: B01D 39/2017 the material being filamentary or fibrous
• CPC Class Codes: B01J 20/06 comprising oxides or hydroxides of metals not provided for in group B01J20/04
• CPC Class Codes: B01J 20/08 comprising aluminium oxide or hydroxide; comprising bauxite
• CPC Class Codes: B01J 20/106 Perlite
• CPC Class Codes: B01J 20/14 Diatomaceous earth
• CPC Class Codes: B01J 20/165 Natural alumino-silicates, e.g. zeolites
• CPC Class Codes: B01J 20/20 comprising free carbon; comprising carbon obtained by carbonising processes
• CPC Class Codes: B01J 20/223 containing metals, e.g. organo-metallic compounds, coordination complexes
• CPC Class Codes: B01J 20/28004 Sorbent size or size distribution, e.g. particle size
• CPC Class Codes: B01J 20/28016 Particle form
• CPC Class Codes: B01J 20/28026 : Particles within, immobilised, dispersed, entrapped in or on a matrix, e.g. a resin
• CPC Class Codes: B01J 20/2803 : Sorbents comprising a binder, e.g. for forming aggregated, agglomerated or granulated products
• CPC Class Codes: B01J 20/28033 : Membrane, sheet, cloth, pad, lamellar or mat
• CPC Class Codes: B01J 20/28042 : Shaped bodies; Monolithic structures
• CPC Class Codes: B01J 20/2808 : being less than 2 nm, i.e. micropores or nanopores
• CPC Class Codes: B01J 20/3007 : Moulding, shaping or extruding
• CPC Class Codes: B01J 20/3021 : Milling, crushing or grinding
• CPC Class Codes: B01J 20/3042 : Use of binding agents; addition of materials ameliorating the mechanical properties of the produced sorbent
• CPC Class Codes: B01J 20/3204 : Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/3265 : with an organic functional group containing a metal, e.g. a metal affinity ligand
• CPC Class Codes: B01J 20/3272 : Polymers obtained by reactions otherwise than involving only carbon to carbon unsaturated bonds
• CPC Class Codes: B01J 2220/4812 : the starting material being of organic character
• CPC Class Codes: C02F 1/004 : using large scale industrial sized filters
• CPC Class Codes: C02F 1/281 : using inorganic sorbents
• CPC Class Codes: C02F 1/283 : using coal, charred products, or inorganic mixtures containing them
• CPC Class Codes: C02F 1/42 : by ion-exchange ion-exchange in general B01J
• CPC Class Codes: C02F 1/444 : by ultrafiltration or microfiltration
• CPC Class Codes: C02F 1/76 : with halogens or compounds of halogens C02F1/4674 takes precedence
• CPC Class Codes: C02F 2303/04 : Disinfection
• CPC Class Codes: C02F 2307/04 : as part of a pitcher or jug
• CPC Class Codes: C12H 1/0408 : with the aid of inorganic added material
• CPC Class Codes: C12H 1/0424 : with the aid of a polymer
• CPC Class Codes: Y10S 264/48 : Processes of making filters
• CPC Class Codes: Y10S 55/05 : Methods of making filter

Abstract

The invention is directed to a microbiological interception enhanced filter medium comprising a microporous structure having a mean flow path of less than about 2 microns and made of an array of active particles. At least a portion of the surface of microporous structure has formed thereon a microbiological interception enhancing agent comprising a cationic material in combination with a biologically active metal. A microbiological interception enhanced filter medium of the present invention provides greater than about 4 log viral interception, and greater than about 6 log bacterial interception.

Claims

1. A filter medium comprising:

a microporous structure comprising an array of active particles, said microporous structure having a mean flow path of less than about 2 microns; and

a microbiological interception enhancing agent comprising a cationic material having a medium to high charge density and a molecular weight greater than about 5000 Daltons, adsorbed on at least a portion of said microporous structure, and a biologically active metal in direct proximity to the cationic material and also on at least a portion of said microporous structure.

2. The filter medium of claim 1 wherein the active particles comprise of activated carbon, activated alumina, zeolites, diatomaceous earth, silicates, aluminosilicates, titanates, bone char, calcium hydroxyapatite, manganese oxides, iron oxides, magnesia, perlite, talc, polymeric particulates, clay, iodated resins, ion exchange resins, ceramics, or combinations thereof.

3. The filter medium of claim 1 wherein said microporous structure further includes a polymeric binder.

4. The filter medium of claim 1 wherein said microporous structure has a mean flow path of less than or equal to about 1 micron.

5. The filter medium of claim 1 wherein said microbiological interception enhancing agent consists of a cationic material on at least a portion of a surface of said microporous structure that has an associated counter ion therewith and wherein a biologically active metal is caused to precipitate with at least a portion of the counter ion associated with the cationic material.

6. The filter medium of claim 5 wherein the cationic material having a counter ion associated therewith is selected from the group consisting of amines, amides, quaternary ammonium salts, imides, benzalkonium compounds, biguanides, aminosilicon compounds, polymers thereof, and combinations thereof.

7. The filter medium of claim 1 wherein said microbiological interception enhancing agent comprises a cationic metal complex including a biologically active metal selected from the group consisting of silver, copper, zinc, cadmium, mercury, antimony, gold, aluminum, platinum, palladium, and combinations thereof.

8. The filter medium of claim 1 wherein the microbiologically enhanced interception agent is formed by treating at least a portion of said microporous structure with a cationic material comprising a homopolymer of diallyl dimethyl ammonium halide followed by precipitation of silver with at least a portion of the halide counter ion associated with the homopolymer of diallyl dimethyl ammonium halide.

9. The filter medium of claim 8 wherein the homopolymer of diallyl dimethyl ammonium chloride has a molecular weight of about 400,000 Daltons.

10. The filter medium of claim 1 wherein the cationic material is adsorbed, chemically bonded, or crosslinked to at least a portion of said microporous structure.

11. The filter medium of claim 1 wherein said microbiological interception enhancing agent has a charge density of greater than about 1 charge unit per about every 20 Angstroms of molecular length.

12. The filter medium of claim 1 wherein said microporous structure comprises a solid composite block of active particles.

13. The filter medium of claim 1 wherein said microporous structure comprises active particles immobilized into a flat sheet structure.

14. The filter medium of claim 1 wherein said microporous structure is formed by extrusion, molding, slip casting, powder coating, wet forming or dry forming of the active particles.

15. The filter medium of claim 1 wherein said filter medium provides greater than about 6 log reduction of microbiological contaminants in an influent when the influent has an empty bed contact time with said filter medium for less than about 12 seconds.

16. A filter system comprising:

a housing having an inlet and an outlet;

a filter medium situated within said housing in fluid communication with the inlet and outlet, said filter medium comprising;

a microporous structure having a mean flow path of less than about 2 microns comprising active particles of activated carbon, activated alumina, zeolites, diatomaceous earth, silicates, aluminosilicates, titanates, bone char, calcium hydroxyapatite, manganese oxides, iron oxides, magnesia, perlite, talc, polymeric particulates, clay, iodated resins, ion exchange resins, ceramics, or combinations thereof; and

a microbiological interception enhancing agent comprising a cationic material having a high charge density, a molecular weight greater than about 5000 Daltons and having an associated counter ion therewith, the cationic material adsorbed on at least a portion of the microporous structure, and wherein a biologically active metal is caused to precipitate with at least a portion of the counter ion associated with the cationic material,

wherein a microbiologically contaminated influent flowing through said housing and contacting said filter medium has at least about 4 log reduction in microbiological contaminants in an effluent flowing from said housing.

17. The filter system of claim 16 wherein the active particles of the microporous structure are a solid composite block.

18. The filter system of claim 16 wherein the active particles of the microporous structure are immobilized into a flat sheet structure.

19. The filter system of claim 16 wherein the active particles of the microporous structure are slip cast, wet-formed or dry-formed.

20. A process of making a filter medium having enhanced microbiological interception capability comprising the steps of:

providing active particles having an average particle size of about 0.1 microns to about 5,000 microns;

treating the active particles with a microbiological interception enhancing agent comprising a cationic material having a high charge density and a molecular weight greater than about 5000 Daltons in combination with a biologically active metal; and

forming the treated active particles into a microporous structure having a mean flow path of less than about 2 microns.

21. The process of claim 20 wherein the step of providing active particles comprises providing active particles of activated carbon, activated alumina, zeolites, diatomaceous earth, silicates, aluminosilicates, bone char, calcium hydroxyapatite, manganese oxides, magnesia, perlite, talc, polymeric particulates, clay, or combinations thereof.

22. The process of claim 20 wherein in the step of treating the active particles with a microbiological interception enhancing agent, the cationic material is selected from the group consisting of amines, amides, quaternary ammonium salts, imides, benzalkonium compounds, biguanides, aminosilicon compounds, polymers thereof, and combinations thereof.

23. The process of claim 20 wherein in the step of treating the active particles with a microbiological interception enhancing agent, the biologically active metal is selected from the group consisting of silver, copper, zinc, cadmium, mercury, antimony, gold, aluminum, platinum, palladium, and combinations thereof.

24. The process of claim 20 wherein the step of forming the treated active particles into a microporous structure further includes the addition of a binder.

25. The process of claim 24 wherein the step of forming the treated active particles into a microporous structure comprises compression molding.

26. The process of claim 24 wherein the step of forming the treated active particles into a microporous structure comprises extrusion.

27. The process of claim 20 wherein the step of forming the treated active particles into a microporous structure comprises immobilizing the treated active particles into a flat sheet substrate.

28. The process of claim 20 wherein the step of forming the treated active particles into a microporous structure comprises slip casting.

29. A process of making a filter medium having enhanced microbiological interception capability comprising the steps of:

providing active particles having an average particle size of about 0.1 microns to about 5,000 microns;

coalescing the active particles into a microporous structure having a mean flow path of less than about 2 microns; and

treating the microporous structure with a microbiological interception enhancing agent comprising a cationic material having a high charge density and a molecular weight greater than about 5000 Daltons in combination with a biologically active metal.

30. The process of claim 29 wherein the step of providing active particles comprises providing active particles of activated carbon, activated alumina, zeolites, diatomaceous earth, silicates, aluminosilicates, bone char, calcium hydroxyapatite, manganese oxides, magnesia, perlite, talc, polymeric particulates, clay, or combinations thereof.

31. The process of claim 29 wherein the step of coalescing the active particles into a microporous structure further includes the addition of a binder.

32. The process of claim 29 wherein the step of treating the microporous structure with a microbiological interception enhancing agent comprises the steps of:

coating at least a portion of the microporous structure with a cationic material having a counter ion associated therewith; and

causing precipitation of a biologically active metal with at least a portion of the counter ion associated with the cationic material on at least a portion of the microporous structure.

33. The process of claim 32 wherein in the step of coating at least a portion of the microporous structure with a cationic material having a counter ion associated therewith, the cationic material is selected from the group consisting of amines, quaternary ammonium salts, benzalkonium compounds, biguanides, aminosilicon compounds, polymers thereof, and combinations thereof.

34. The process of claim 32 wherein in the step of causing precipitation of a biologically active metal, the metal is selected from the group consisting of silver, copper, zinc, cadmium, mercury, antimony, gold, aluminum, platinum, palladium, and combinations thereof.

35. A method of removing microbiological contaminants from a fluid comprising the steps of:

providing a filter medium comprising

a microporous structure comprising active particles and having a mean flow path of less than about 2 microns; and

a microbiological interception enhancing agent comprising a cationic material having a medium to high charge density and a molecular weight greater than about 5000 Daltons in combination with a biologically active metal, adsorbed on at least a portion of said microporous structure;

contacting a microbiologically contaminated fluid to the filter medium for a period of time of less than or equal to about 12 seconds; and

obtaining an effluent having greater than about 4 log reduction of microbiological contaminants.

36. The method of claim 35 wherein in the step of providing a filter medium, the microporous structure comprises active particles including activated carbon.

37. The method of claim 35 wherein in the step of providing a filter medium, the microbiological interception enhancing agent consists of a cationic material having a counter ion associated therewith, adsorbed on at least a portion of the microporous structure and wherein a biologically active metal is caused to precipitate with at least a portion of the counter ion associated with the cationic material.

38. The method of claim 35 wherein in the step of providing a filter medium, the microbiological interception enhancing agent consists of a metal-cationic material-halide complex wherein the cationic material is adsorbed, chemically bonded or crosslinked to at least a portion of said microporous structure.