Integrated filter combining physical adsorption and electrokinetic adsorption

• US 6,274,041 B1
• Filed: 12/14/1999
• Issued: 08/14/2001
• Est. Priority Date: 12/18/1998
• Status: Active Grant

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: McGrath, Kevin P., Williamson, Bruce S.
• Primary Examiner(s): Drodge, Joseph W.
• Application Number:
  US09/461,088
• Time in Patent Office: 609 Days
• Field of Search: 210/243, 210/266, 210/282, 210/290, 210/489, 210/490, 210/492, 210/502.1, 210/505, 210/508, 210/509, 210/510.1, 553/15, 553/18, 553/21, 553/23, 553/32
• US Class Current: 210/243
• CPC Class Codes: B01D 2253/102 Carbon
• CPC Class Codes: B01D 2253/104 Alumina
• CPC Class Codes: B01D 2253/106 Silica or silicates
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2253/1128 Metal sulfides
• CPC Class Codes: B01D 2253/202 Polymeric adsorbents
• CPC Class Codes: B01D 2253/25 Coated, impregnated or composite adsorbents
• CPC Class Codes: B01D 2253/34 Specific shapes
• CPC Class Codes: B01D 2257/2064 Chlorine
• CPC Class Codes: B01D 2257/60 Heavy metals or heavy metal compounds
• CPC Class Codes: B01D 2257/90 Odorous compounds not provided for in groups B01D2257/00 - B01D2257/708
• CPC Class Codes: B01D 2257/91 Bacteria; Microorganisms
• CPC Class Codes: B01D 2259/4146 Contiguous multilayered adsorbents
• CPC Class Codes: B01D 53/0431 Beds with radial gas flow

Abstract

An integrated filter for removing impurities from a fluid stream. The filter includes a first element adapted to remove at least some of the impurities by physical adsorption, and a second element adapted to remove at least some of the impurities by electrokinetic adsorption. Either or both of the first element and the second element further may be adapted to remove at least some of the impurities by sieving. The first element generally may be composed of loose particles or granules, or the first element may be composed of a porous block of an adsorbent, wherein the block is permeable to fluids and has interconnected pores therethrough. The second element generally is composed of a porous, charge-modified fibrous web which includes fibers prepared from a thermoplastic polymer. For example, the thermoplastic polymer may be a polyolefin. As another example, the porous, charge-modified fibrous web may be a nonwoven web, such as a meltblown or microfiber glass web. Alternatively, both the first and second elements may be in the form of a sheet.

Claims

1. An integrated filter for removing impurities from a fluid stream, the filter comprising:

a first element adapted to remove at least some of the impurities by physical adsorption; and

a second element adapted to remove at least some of the impurities by electrokinetic adsorption.

2. The integrated filter of claim 1, in which the first element further is adapted to remove at least some of the impurities by sieving.

3. The integrated filter of claim 1, in which the second element further is adapted to remove at least some of the impurities by sieving.

4. The integrated filter of claim 1, in which the first element is comprised of a porous block of an adsorbent, wherein the block is permeable to fluids and has interconnected pores therethrough.

5. The integrated filter of claim 4, in which the first element further is comprised of a granular adsorbent component and a thermoplastic binder component.

6. The integrated filter of claim 4, in which the adsorbent is activated carbon, activated alumina, activated bauxite, fuller'"'"'s earth, diatomaceous earth, silica gel, or calcium sulfate.

7. The integrated filter of claim 1, in which the second element is comprised of a porous, charge-modified fibrous web comprising fibers prepared from a thermoplastic polymer.

8. The integrated filter of claim 7, in which the thermoplastic polymer is a polyolefin.

9. The integrated filter of claim 8, in which the porous, charge-modified fibrous web is a meltblown web.

10. The integrated filter of claim 9, in which said meltblown web is coated with a functionalized cationic polymer.

11. The integrated filter of claim 1, in which the second element is comprised of a packed bed of particles.

12. The integrated filter of claim 11, in which said particles are coated with a functionalized cationic polymer.

13. The integrated filter of claim 1, in which the second element is comprised of a microfiber glass web.

14. The integrated filter of claim 13, in which said microfiber glass web is coated with a functionalized cationic polymer.

15. The integrated filter of claim 1, in which the first element is comprised of a

coextruded block composite comprising:

a porous first block which

is permeable to fluids;

is comprised of a granular adsorbent component and a thermoplastic binder component; and

has interconnected pores therethrough having a first average diameter; and

a second block;

in which

at least one of the first block and the second block is continuous; and

at least a portion of the second block is contiguous with at least a portion of the first block.

16. An integrated filter for removing impurities from a fluid stream, the filter comprising:

a first element adapted to remove at least some of the impurities by physical adsorption; and

a second element adapted to remove at least some of the impurities by electrokinetic adsorption;

in which

the first element is comprised of a porous block of an adsorbent, wherein the block is permeable to fluids and has interconnected pores therethrough; and

the second element is comprised of a porous, charge-modified fibrous web comprising fibers prepared from a thermoplastic polymer.

17. The integrated filter of claim 16, in which the first element further is adapted to remove at least some of the impurities by sieving.

18. The integrated filter of claim 16, in which the second element further is adapted to remove at least some of the impurities by sieving.

19. The integrated filter of claim 16, in which the thermoplastic polymer is a polyolefin.

20. The integrated filter of claim 16, in which the porous, charge-modified fibrous web is a meltblown web.

21. The integrated filter of claim 16, in which the porous, charge-modified fibrous web is a microfiber glass web.

22. The integrated filter of claim 16, in which the first element further is comprised of a granular adsorbent component and a thermoplastic binder component.

23. The integrated filter of claim 22, in which the adsorbent is activated carbon, activated alumina, activated bauxite, fuller'"'"'s earth, silica gel, or calcium sulfate.

24. An integrated filter for removing impurities from a fluid stream, the filter comprising:

a first element adapted to remove at least some of the impurities by electrokinetic adsorption

a second element adjacent to and contiguous with the first element and adapted to remove at least some of the impurities by physical adsorption; and

a third element adjacent to and contiguous with the second element and adapted to remove at least some of the impurities by electrokinetic adsorption.

25. The integrated filter of claim 24, in which each element is a sheet.