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Publication numberCA2474858 A1
Publication typeApplication
Application numberCA 2474858
PCT numberPCT/US2003/000067
Publication date7 Aug 2003
Filing date2 Jan 2003
Priority date31 Jan 2002
Also published asCA2474858C, CA2474980A1, CA2474980C, CN1278757C, CN1280001C, CN1625428A, CN1625434A, DE60319810D1, DE60320542D1, DE60320542T2, EP1483028A2, EP1483028A4, EP1483028B1, EP1483039A1, EP1483039A4, EP1483039B1, US6835311, US6913154, US6953604, US6959820, US6998058, US7008537, US7011753, US7144533, US20030168401, US20030196963, US20030196964, US20030201231, US20030205529, US20030205530, US20030205531, US20030213750, WO2003063996A2, WO2003063996A3, WO2003064013A1
Publication numberCA 2474858, CA 2474858 A1, CA 2474858A1, CA-A1-2474858, CA2474858 A1, CA2474858A1, PCT/2003/67, PCT/US/2003/000067, PCT/US/2003/00067, PCT/US/3/000067, PCT/US/3/00067, PCT/US2003/000067, PCT/US2003/00067, PCT/US2003000067, PCT/US200300067, PCT/US3/000067, PCT/US3/00067, PCT/US3000067, PCT/US300067
InventorsEvan E. Koslow
ApplicantKoslow Technologies Corporation, Evan E. Koslow, Kx Industries, L.P., Kx Technologies Llc
Export CitationBiBTeX, EndNote, RefMan
External Links: CIPO, Espacenet
Microporous filter media, filtration systems containing same, and methods of making and using
CA 2474858 A1
Abstract
The invention is directed to a microbiological interception enhanced filter medium, preferably having an adsorbent prefilter located upstream from the filter medium. Preferably, the prefilter is adapted to remove natural organic matter in an influent prior to the influent contacting themicrobiological interception enhanced filter medium, thereby preventing loss of charge on the filter medium. The microbiological interception enhanced filter medium is most preferably comprised of fibrillated cellulose nanofibers, in particular, lyocell nanofibers. At least a portion of the surface of the at least some of the nanofibers have formed thereon a microbiological interception enhancing agent comprising a cationic metal complex. A filter medium of the present invention provides greater than about 4 log viral interception, and greater than about 6 log bacterial interception.
Description  available in
Claims(65)
1. A filter medium comprising:
a microporous structure having a mean flow path of less than or equal to about 1 micron; and a microbiological interception enhancing agent comprising a cationic metal complex capable of imparting a positive charge on at least a portion of said microporous structure.
2. A filter medium according to claim 1 wherein said microporous structure comprises a plurality of nanofibers having a fiber diameter of less than about 1000 nanometers.
3. A filter medium according to claim 2 wherein the nanofibers comprise organic nanofibers, inorganic nanofibers, or a mixture thereof.
4. A filter medium according to claim 2 wherein the nanofibers comprise substantially fibrillated lyocell nanofibers.
5. A filter medium according to claim 4 wherein the fibrillated lyocell nanofibers have a Canadian Standard Freeness of less than or equal to about 45.
6. A filter medium according to claim 1 wherein said microporous structure is a membrane comprising an organic material, an inorganic material, or a mixture thereof.
7. A filter medium according to claim 6 wherein the membrane comprises a polymer material.
8. A filter medium according to claim 1 wherein said microbiological interception enhancing agent consists of a cationic metal complex wherein a cationic material on a surface of said microporous structure 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.
9. A filter medium according to claim 8 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.
10. A filter medium according to claim 1 wherein the cationic metal complex includes a biologically active metal selected from the group consisting of silver, copper, zinc, cadmium, mercury, antimony, gold, aluminum, platinum, palladium, and combinations thereof.
11. A filter medium according to claim 1 wherein the cationic metal complex 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.
12. A filter medium as in any one of claims 1 through 11 wherein said microporous structure is combined with an adsorbent prefilter medium containing 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.
13. A filter medium comprising:
as adsorbent prefilter having immobilized therein a material capable of removing charge-reducing contaminants;
a microporous structure, disposed downstream from said adsorbent layer, comprising a plurality of nanofibers, said microporous structure having a mean flow path of less than about 0.6 micron; and a microbiological interception enhancing agent comprising a silver-cationic material-halide complex having a high charge density, coated on at least a portion of a surface of at least some of the plurality of nanofibers of said microporous structure.
14. A filter medium according to claim 13 wherein said microbiological interception enhancing agent consists of a silver-cationic material-halide complex wherein a homopolymer of diallyl dimethyl ammonium on a surface of said microporous structure has a halide counter ion associated therewith and wherein silver is precipitated with at least a portion of the halide counter ion.
15. A filter medium as in any one of claims 1, 12, and 13 wherein the homopolymer of diallyl dimethyl ammonium halide has a molecular weight of greater than or equal to about 400,000 Daltons.
16. A filter medium as in any one of claims 1, 13, 14, and 15 wherein said microporous structure incorporates one or more materials selected from the group consisting 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, and combinations thereof.
17. A filter medium as in any one of claims 1 and 13 wherein said microporous structure further includes a binder.
18. A filter medium as in any one of claims 1 and 13 further including a particulate prefilter.
19. A filter medium as in any one of claims 2 and 13 wherein the plurality of nanofibers are made from material selected from the group consisting of polymers, ion-exchange resins, engineered resins, ceramics, cellulose, rayon, wool, silk, glass, metal, litanates activated alumina, ceramics activated carbon, silica, zeolites, diatomaceous earth, activated bauxite, fuller's earth, calcium hydroxyapatite, and combinations thereof.
20. A filter system comprising:
a bed of granular material capable of removing charge-reducing contaminants;
a microporous structure, disposed downstream from said granular bed, having a mean flow path of less than about 0.6 micron;
and a microbiological interception enhancing agent comprising a silver-cationic material-halide complex having a high charge density, coated on at least a portion of a surface of said microporous structure.
21. A filter system comprising:
a solid composite block comprising a material capable of removing charge-reducing contaminants;

a microporous structure, disposed downstream from said block, having a mean flow path of less than about 2.0 microns; and a microbiological interception enhancing agent comprising a silver-cationic material-halide complex having a high charge density, coated on at least a portion of a surface of said microporous structure.
22. A filter system as in any one of claims 20 and 21 further including a particulate prefilter.
23. A filter system as in any one of claims 20 and 21 wherein the silver-cationic material-halide complex comprises a homopolymer of dially dimethyl ammonium on a surface of said microporous structure having a halide counter ion associated therewith and wherein silver is precipitated with at least a portion of the halide counter ion.
24. A filter system as in any one of claims 20 and 21 wherein the silver-cationic material-halide complex comprises a homopolymer of dially dimethyl ammonium on a surface of said microporous structure having a halide counter ion associated therewith wherein the homopolymer of diallyl dimethyl ammonium chloride has a molecular weight of greater than or equal to about 400,000 Daltons, and wherein silver is precipitated with at least a portion of the halide counter ion,.
25. A filter system as in any one of claims 20 and 21 wherein the material capable of removing charge-reducing contaminants comprises 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.
26. A filter system as in any one of claims 20 and 21 wherein said microporous structure incorporates one or more materials selected from the group consisting 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, and combinations thereof.
27. A filter system as in any one of claims 20 and 21 wherein said microporous structure further includes a binder.
28. A process of making a filter medium comprising the steps of:
providing a microporous structure having a mean flow path of less than about 1 micron; and coating at least a portion of the microporous structure with a microbiological interception enhancing agent, the microbiological interception enhancing agent comprising a cationic metal complex capable of imparting a positive charge on at least a portion of the microporous structure.
29. A process according to claim 28 wherein the step of providing a microporous structure comprises forming a plurality of nanofibers having a fiber diameter of less than about 1000 nanometers into the microporous structure.
30. A process according to claim 28 wherein the step of providing a microporous structure comprises forming a plurality of nanofibers, wherein the nanofibers comprise organic nanofibers, inorganic nanofibers, or a mixture thereof, into the microporous structure.
31. A process according to claim 28 wherein the step of providing a microporous structure comprises forming a plurality of substantially fibrillated lyocell nanofibers wherein at least a portion of the fibrillated lyocell nanofibers are about 1 millimeter to about 8 millimeters in length having a diameter of about 250 nanometers, into the microporous structure.
32. A process according to claim 28 wherein the step of forming a plurality of substantially fibrillated lyocell nanofibers comprises forming a plurality of substantially fibrillated lyocell nanofibers having a Canadian Standard Freeness of less than or equal to about 45, into the microporous structure.
33. A process according to claim 28 wherein the step of providing a microporous structure comprises providing a membrane comprising an organic material, an inorganic material, or a mixture thereof.
34. A process for making a filter medium comprising the steps of:
providing a plurality of nanofibers;
coating at least a portion of a surface of at least some of the plurality of nanofibers with a microbiological interception enhancing agent, the microbiological intercepting agent comprising a cationic metal complex; and forming said nanofibers into a microporous structure having a mean flow path of less than about 1 micron.
35. A process for making a filter medium comprising the steps of:
providing a plurality of polymer nanofibers;
coating at least a portion of a surface of at least some of the plurality of polymer nanofibers with a microbiological interception enhancing agent, the microbiological intercepting agent comprising a cationic metal complex; and forming a microporous structure having a mean flow path of less than about 1 micron.
36. A process for making a filter medium comprising the steps of:
providing a plurality of cellulose nanofibers;
coating at least a portion of a surface of at least some of the plurality of cellulose nanofibers with a microbiological interception enhancing agent, the microbiological intercepting agent comprising a cationic metal complex; and forming a microporous structure having a mean flow path of less than about 1 micron.
37. A process of making a filter medium comprising the steps of:
providing a membrane having a mean flow path of less than about 1 micron; and coating at least a portion of the membrane with a microbiological interception enhancing agent, the microbiological interception enhancing agent comprising a cationic metal complex capable of imparting a positive charge on at least a portion of the membrane.
38. A process according to claim 37 wherein the step of coating comprises treating at least a portion of the membrane with a cationic material having a counter ion associated therewith to form a cationically charged membrane;

exposing the cationically charged membrane to a biologically active metal salt; and precipitating a biologically-active metal complex with at least a portion of the counter ion associated with the cationic material on at least a portion of the membrane.
39. A process for making a filter medium comprising the steps of:
providing a plurality of nanofibers;
coating at least a portion of a surface of at least some of the plurality of said nanofibers with a microbiological interception enhancing agent, the microbiological intercepting agent comprising a silver-amine-halide complex having a medium to high charge density and a molecular weight greater than 5000 Daltons; and forming a microporous structure having a mean flow path of less than or about 0.6 microns.
providing an adsorbent prefilter comprising a material capable of removing charge-reducing contaminants from an influent, and placing said adsorbent prefilter upstream of said microporous structure.
40. A process for making a filter system comprising the steps of:
providing an adsorbent prefilter comprising a material capable of removing charge-reducing contaminants from an influent, wherein the material is immobilized into a solid composite block;
providing a plurality of nanofibers;
coating at least a portion of a surface of at least some of the plurality of said nanofibers with a microbiological interception enhancing agent, the microbiological intercepting agent comprising a silver-amine-halide complex having a medium to high charge density and a molecular weight greater than 5000 Daltons; and forming a microporous structure comprising the plurality of nanofibers having a mean flow path of less than or about 0.6 microns, wherein the microporous structure is downstream from the adsorbent prefilter.
41. A process as in any one of claims 28, 34, 35, 36, 37, 39, and 40 further including the step of incorporating one or more ingredients to the filter ~
medium selected from the group consisting 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, and combinations thereof.
42. A process as in any one of claims 34, 36, 39, and 40 wherein the step of providing a plurality of nanofibers comprising forming a plurality of fibrillated lyocell nanofibers and forming the fibrillated lyocell nanofibers into the microporous structure.
43. A process as in any one of claims 34, 35, and 36 wherein the step of coating comprises:
treating at least a portion of the plurality of nanofibers with a cationic material having a counter ion associated therewith to form a cationically charged fiber material;
exposing the cationically charged fiber material to a biologically active metal salt; and precipitating a biologically-active metal complex with at least a portion of the counter ion associated with the cationic material on at least a portion of the cationically charged fiber material.
44. A process as in any one of claims 34, 35, and 36 wherein in the step of coating, at least a portion of the plurality of nanofibers are treated with a cationic material having a counter ion associated therewith to form a cationically charged fiber material, wherein the cationic material is selected from the group consisting of amines, amides, quaternary ammonium salts, imides, benzalkonium compounds, biguanides, pyrroles aminosilicon compounds, polymers thereof, and combinations thereof.
45. A process as in any one of claims 34, 35, and 36 wherein in the step of coating, the cationically charged fiber material is exposed to a biologically active metal salt, wherein the biologically active metal is selected from the group consisting of silver, copper, zinc, cadmium, mercury, antimony, gold, aluminum, platinum, palladium, and combinations thereof.
46. A process as in any one of claims 34, 35, and 36 wherein in the step of coating, the cationic metal complex comprises a metal-amine-halide complex.
47. A process as in any one of claims 34, 35, and 36 wherein in the step of coating, the cationic metal complex comprises a silver-amine-halide complex.
48. A process as in any one of claims 34, 35, 36, 37, 39, and 40 further including the step of providing a prefilter capable of removing charge-reducing contaminants from an influent prior to the influent contacting the microporous structure.
49. A process as in any one of claims 29, 30, 34, 39, and 40 wherein the step of providing a plurality of nanofibers, the nanofibers are made from a material selected from the group consisting of polymers, ion-exchange resins, engineered resins, ceramics, cellulose, rayon, wool, silk, glass, metal, litanates activated alumina, ceramics activated carbon, silica, zeolites, diatomaceous earth, activated bauxite, fuller's earth, calcium hydroxyapatite, and combinations thereof.
50. A process as in any one of claims 34, 35, 36, 39, and 40 wherein the step of forming the microporous structure comprises a wet laid process, a dry laid melt blown, or dry laid spun-bonding.
51. A process as in any one of claims 34, 35, 36, 39, and 40 wherein the step of forming the microporous structure includes incorporating into the microporous structure one or more ingredients selected from the group consisting 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, and combinations thereof.
52. A method of removing microbiological contaminants in a fluid comprising the steps of:
providing a filter medium having a microporous structure having a mean flow path of less than about 1 micron, the microporous structure having coated on at least a portion thereof a microbiological interception enhancing agent comprising a cationic metal complex wherein said cationic material has a medium to high charge density and a molecular weight greater than about 5000 Daltons;

contacting the fluid to the filter medium for greater than about 3 seconds; and obtaining at least about 6 log reduction of microbiological contaminants smaller than the mean flow path of the filter medium that pass through the filter medium.
53. A method according to claim 52 wherein the step of providing a filter medium comprises providing a filter medium wherein the microporous structure comprises a plurality of nanofibers such that the microporous structure has a mean flow path of less than about 0.6.microns.
54. A method according to claim 52 wherein the step of providing a filter medium comprises providing a filter medium wherein the microporous structure comprises a plurality of fibrillated lyocell nanofibers such that the microporous structure has a mean flow path of less than about 0.6 microns.
55. A method according to claim 52 wherein the step of providing a filter medium comprises providing a filter medium wherein the microporous structure comprises a membrane such that the microporous structure has a mean flow path of less than about 0.6 microns.
56. A method according to claim 52 wherein in the step of providing a filter medium, the microbiological interception enhancing agent is coated on the microporous structure by treating at least a portion of the microporous structure with a quaternary ammonium salt to form a cationically charged microporous structure;

exposing the cationically charged microporous structure to a biologically active metal salt; and precipitating biologically-active metal with at least a portion of a counter ion associated with the quaternary ammonium salt on at least a portion of the microporous structure.
57 A method according to claim 52 wherein in the step of providing a filter medium, the microbiological interception enhancing agent comprises a cationic polymer having a medium to high charge density and a molecular weight of about 400,000 Daltons, and a biologically-active metal is precipitated with at least a portion of the counter ion associated with the cationic polymer.
58. A gravity-flow filtration system for treating, storing, and dispensing fluids comprising:
a first reservoir for holding a fluid to be filtered;
a filter medium in fluid communication with said first reservoir, said filter medium comprising a microporous structure with a mean flow path of less than about 1 micron, and wherein said filter medium is so treated as to provide at least about 4 log reduction of microbiological contaminants smaller than the mean flow path of said filter medium; and a second reservoir in fluid communication with said filter medium for collecting a filtered fluid.
59. The gravity-flow filtration system according to claim 58 wherein said filter medium has a volume of less than about 500 cm3 and has an initial flow rate of greater than about 25 ml/minute.
60. A filter medium as in one of claims 1 to 18 as substantially described herein with reference to and/or illustrated in the accompanying drawings.
61. A filter medium according to any one of claims 1 to 18 as described herein in any of the examples.
62. A filter system as in any of claims 19 to 27 or 58 to 59 substantially described herein with reference to and/or illustrated in the accompanying drawings.
63. A filter system as in any of claims 19 to 27 or 58 to 59 as described herein in any of the examples.
64. A process of making a filter medium as in any one of claims 28 to 51.
65. A method of removing microbiological contaminants in a fluid as in any one of claims 52 to 57.
Classifications
International ClassificationB01D29/15, A01N25/26, C02F1/50, B01J20/26, B01D39/18, A61L2/02, A61L9/16, C02F1/42, B01D71/06, C12H1/056, B01J20/28, A61L2/00, F24F3/16, B01D37/02, B01J20/32, C02F1/00, B01D39/20, C02F1/76, C12H1/044, B01J20/24, C02F1/44, B01D39/06, B01D39/04, C02F1/28, B01D39/16
Cooperative ClassificationB01J20/3204, B01J20/3293, B01J20/3212, B01J20/3236, C02F1/283, C02F1/76, B01J20/28007, B01J20/28023, C02F1/001, C02F1/42, C02F2303/04, A61L2/0082, B01J20/28014, B82Y30/00, C12H1/0424, B01J2220/42, C02F1/444, B01D37/02, C12H1/0408, B01D39/2017, C02F1/003, C02F2307/04, C02F1/505, Y10T428/249978, A61L2/022, B01D39/1623, C02F1/004, B01D39/18, A61L9/16, B01D29/15, C02F1/281, B01D2201/34, A61L2/0017, Y10T428/249982, Y10T428/249967
European ClassificationB01J20/28B4D, B01J20/28D8, B01J20/28D, C02F1/00D6, B01D29/15, B01J20/32D4D, B82Y30/00, A61L2/02F, B01D39/20B4, B01D37/02, A61L9/16, C02F1/00D4, C12H1/04C4, A61L2/00P4, A61L2/00P2A, C12H1/04B, C02F1/44D, B01J20/32, B01D39/18, B01D39/16B4, C02F1/50B
Legal Events
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