Polyvinyl alcohol filter media

• US 20040192135A1
• Filed: 12/24/2003
• Published: 09/30/2004
• Est. Priority Date: 12/24/2002
• Status: Abandoned Application

• Current Assignee: Microtek Medical Holdings Incorporated (Ecolab, Inc.)
• Original Assignee: Microtek Medical Holdings Incorporated (Ecolab, Inc.)
• Inventors: Steward, John, Johnston, Jordan M., Ding, Youzhen, Lee, Baosheng
• Application Number:
  US10/746,152
• Publication Number:
  US 20040192135A1
• Time in Patent Office: Days
• US Class Current: 442/181
• CPC Class Codes: B01D 2239/0407 comprising particulate additives, e.g. adsorbents
• CPC Class Codes: B01D 2239/0654 Support layers
• CPC Class Codes: B01D 2239/0695 Wound layers
• CPC Class Codes: B01D 2239/1216 Pore size
• CPC Class Codes: B01D 39/083 of organic material
• 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: Y10T 442/30 Woven fabric [i.e., woven strand or strip material]
• CPC Class Codes: Y10T 442/40 Knit fabric [i.e., knit strand or strip material]
• CPC Class Codes: Y10T 442/60 Nonwoven fabric [i.e., nonwoven strand or fiber material]

Abstract

Filters comprising water-soluble polyvinyl alcohol material are disclosed. Methods of making and using filters formed from water-soluble polyvinyl alcohol material are also disclosed.

Claims

1. A filter comprising polyvinyl alcohol.

2. The filter of claim 1, wherein the filter comprises:

(a) a filtration media of fibrous material formed from polyvinyl alcohol; and

(b) a support for the fibrous material.

3. The filter of claim 2, wherein the filtration media comprises polyvinyl alcohol yarn or roving, and the support comprises a core;

wherein the yarn or roving is wound onto the core.

4. The filter of claim 3, wherein the core comprises a water-soluble or water-degradable polymer.

5. The filter of claim 2, wherein the filtration media comprises a woven, nonwoven or knitted fabric of polyvinyl alcohol fibers, and the support comprises a structural support in contact with the fibrous material.

6. The filter of claim 5, wherein the structural support comprises a water-soluble or water-degradable polymer.

7. The filter of claim 1, wherein the filter has a nominal pore size ranging from about 0.1 microns (μ

m) to about 2500 μ

m.

8. The filter of claim 1, wherein the filter has a nominal pore size ranging from about 0.1 μ

m to about 1.0 μ

m.

9. The filter of claim 1, wherein the filter has a nominal pore size ranging from about 10.0 μ

m to about 100 μ

m.

10. The filter of claim 2, wherein the filtration media consists essentially of fibrous material formed from polyvinyl alcohol.

11. The filter of claim 2, wherein the filtration media consists of fibrous material formed from polyvinyl alcohol.

12. The filter of claim 2, wherein the filtration media and the support comprise polyvinyl alcohol.

13. The filter of claim 2, wherein the filtration media and the support consists essentially of polyvinyl alcohol.

14. A method of reducing an amount of radioactive waste generated by a contaminated filter, wherein the method comprises:

(a) disposing of the filter by placing the filter in an aqueous bath under condition such that at least a portion of the filter becomes soluble.

15. The method of claim 14, wherein the aqueous bath has a bath temperature of greater than about 90°

C.

16. The method of claim 14, wherein the aqueous bath contains a polymer degradation-enhancing reactant, a precursor to a polymer degradation-enhancing reactant, an oxidizer, ozone, or a combination thereof.

17. The method of claim 14, wherein the filter comprises a fiber, a fabric, a film, or a combination thereof containing water-soluble polyvinyl alcohol material.

18. The method of claim 14, wherein the filter comprises a nonwoven fabric containing water-soluble polyvinyl alcohol material.

19. The method of claim 14, wherein the filter comprises a woven fabric containing water-soluble polyvinyl alcohol material.

20. The method of claim 14, wherein the filter comprises a knitted fabric containing water-soluble polyvinyl alcohol material.

21. The method of claim 14, wherein the filter comprises water-soluble polyvinyl alcohol material.

22. The method of claim 21, wherein the filter further comprises one or more additional materials selected from the group consisting of polyacrylic acid;

polymethacrylic acid;

polyacrylamide;

water-soluble cellulose derivatives comprising methyl celluloses, ethyl celluloses, hydroxymethyl celluloses, hydroxypropyl methyl celluloses, and carboxymethyl celluloses;

carboxymethylchitin;

polyvinyl pyrrolidone;

ester gum;

water-soluble derivatives of starch comprising hydroxypropyl starch and carboxymethyl starch;

water-soluble polyethylene oxides;

alkali water-soluble materials comprising ethylene copolymers of acrylic acid (EAA) and methacrylic acid (EMAA), and salts thereof; and

ionomers containing acrylic acid and/or methacrylic acid.

23. The method of claim 21, wherein the water-soluble material comprises polyvinyl alcohol with or without acetyl groups, cross-linked or uncross-linked.

24. The method of claim 14, wherein the filter is contaminated due to exposure to radioactive material, wherein the radioactive material comprises a transuranic element, a fission product, a natural radioactive element, an activation product from a nuclear process, a medical isotope, or a combination thereof.

25. The method of claim 14, further comprising one or more of the following steps:

(i) placing the filter into a disposal reactor;

(ii) introducing water into the reactor to form an aqueous solution;

(iii) adding one or more components to the disposal vessel, wherein the one or more components comprise a polymer degradation-enhancing reactant, a precursor to a polymer degradation-enhancing reactant, an oxidizer, ozone, or a combination thereof;

(iv) heating the aqueous solution to (a) optionally convert the precursor, when present, to a degradation-enhancing reactant, and (b) reacting the degradation-enhancing reactant with the water-soluble polymer to form one or more degradation products;

(v) filtering non-solubilized material from the second aqueous solution;

(vi) optionally, measuring a parameter to indicate a concentration of polymer material in the aqueous solution;

(vii) separating radioactive material from the aqueous solution by a separation technique;

(viii) collecting the radioactive material for proper disposal;

(ix) optionally, altering or neutralizing a pH of the aqueous solution substantially free of radioactive material;

(x) biodegrading the one or more degradation products in the aqueous solution substantially free of radioactive material to form CO₂, water and biomass; and

(xi) removing any insoluble components from the reactor.

26. A method of reducing an amount of radioactive waste generated by at least one contaminated product, wherein the method comprises:

disposing of the at least one contaminated product by placing the at least one contaminated product in an aqueous bath under condition such that at least a portion of the product becomes soluble; and

filtering any non-solubilized material from the aqueous bath using at least one filter comprising water-soluble polyvinyl alcohol material.

27. The method of claim 26, wherein the aqueous bath in the disposal step contains a polymer degradation-enhancing reactant, a precursor to a polymer degradation-enhancing reactant, an oxidizer, ozone, or a combination thereof.

28. The method of claim 26, wherein the at least one contaminated product comprises at least one garment, protective clothing, coverall, bootie, face mask, glove, apparel, linen, drape, towel, fabric, film, laminate containing at least one fabric or film, sponge, mop head, web, bag, gauze, pad, wipe, pillow, bandage, or combination thereof.

29. The method of claim 26, wherein the at least one contaminated product comprises water-soluble material selected from the group consisting of polyvinyl alcohol;

polyacrylic acid;

polymethacrylic acid;

polyacrylamide;

water-soluble cellulose derivatives comprising methyl celluloses, ethyl celluloses, hydroxymethyl celluloses, hydroxypropyl methyl celluloses, and carboxymethyl celluloses;

carboxymethylchitin;

polyvinyl pyrrolidone;

ester gum;

water-soluble derivatives of starch comprising hydroxypropyl starch and carboxymethyl starch;

water-soluble polyethylene oxides;

alkali water-soluble materials comprising ethylene copolymers of acrylic acid (EAA) and methacrylic acid (EMAA), and salts thereof; and

ionomers containing acrylic acid and/or methacrylic acid.

30. The method of claim 29, wherein the water-soluble material comprises polyvinyl alcohol with or without acetyl groups, cross-linked or uncross-linked.

31. The method of claim 26, wherein the at least one contaminated product is contaminated due to exposure to radioactive material, wherein the radioactive material comprises a transuranic element, a fission product, a natural radioactive element, an activation product from a nuclear process, a medical isotope, or a combination thereof.

32. The method of claim 26, further comprising one or more of the following steps:

(i) placing the at least one contaminated product into a disposal reactor;

(ii) introducing water into the reactor to form an aqueous solution;

(iii) adding one or more components to the disposal vessel, wherein the one or more components comprise a polymer degradation-enhancing reactant, a precursor to a polymer degradation-enhancing reactant, an oxidizer, ozone, or a combination thereof;

(iv) heating the aqueous solution to (a) optionally convert the precursor, when present, to a degradation-enhancing reactant, and (b) reacting the degradation-enhancing reactant with the water-soluble polymer to form one or more degradation products;

(v) optionally, measuring a parameter to indicate a concentration of polymer material in the aqueous solution;

(vi) separating radioactive material from the aqueous solution by a separation technique;

(vii) collecting the radioactive material for proper disposal;

(viii) optionally, altering or neutralizing a pH of the aqueous solution substantially free of radioactive material;

(ix) biodegrading the one or more degradation products in the aqueous solution substantially free of radioactive material to form CO₂, water and biomass; and

(x) removing any insoluble components from the reactor.

33. The method of claim 32, wherein the filtration step comprises passing the aqueous solution through a particulate filter having a nominal pore size of about 10 microns to about 100 microns, wherein the filter comprises water-soluble polyvinyl alcohol material.

34. The method of claim 32, wherein the separation step (vi) comprises passing the aqueous solution through a second particulate filter having a nominal pore size of from about 0.1 microns to about 1.0 microns and then circulating the aqueous solution through an ion exchange bed, wherein the second particulate filter comprises water-soluble polyvinyl alcohol material.

35. A process for treating a material comprising at least one polymer, comprising the steps:

introducing at least one oxidizing agent and a material comprising at least one polymer into an aqueous environment, wherein said at least one polymer is a polymer capable of being reacted, degraded or broken down into at least one degradation product;

reacting, degrading or breaking down at least a portion of the at least one polymer under conditions effective to provide at least one degradation product; and

filtering the aqueous environment using a filter comprising water-soluble polyvinyl alcohol material.