Water filter cartridge

1. A disposable water filter cartridge for use in a residential gravity-feed pitcher, said water filter cartridge comprising:

a filter housing defining a chamber having an upper inlet opening and at least one lower outlet opening having a combined total area of about 0.03 to 0.04 square inches; and

a filter media disposed in said chamber, said filter media comprising a granular mixture of at least 6 grams of agglomerated nanoparticles of anatase titania crystal titanium dioxide interspersed with less than or equal to 100 grams of granular activated charcoal;

wherein said at least one lower outlet opening is sized to limit a flow rate through said filter media to at least about 0.3 liters per minute at gravity-feed pressure in the residential gravity-feed water filter pitcher.

2. The water filter cartridge of claim 1 , wherein said agglomerated nanoparticles of anatase titania crystal titanium dioxide are substantially evenly distributed with said granular activated charcoal.

3. The water filter cartridge of claim 1 , wherein said filter media comprises approximately 15 to 20 grams of said agglomerated nanoparticles of anatase titania crystal titanium dioxide and approximately 55 grams of said granular activated charcoal.

4. The water filter cartridge of claim 1 , wherein said agglomerated nanoparticles of anatase titania crystal titanium dioxide have a nominal grain size of about 16 to 60 mesh, and said granular activated charcoal have a nominal grain size of about 40 to 45 mesh.

5. The water filter cartridge of claim 1 , wherein said filter housing comprises a sidewall having an annular upper region and a seal disposed around an outer periphery of said annular upper region.

6. The water filter cartridge of claim 5 , wherein said seal comprises a thin flange region that extends radially outwardly from said sidewall and is configured to flex upwardly upon insertion of the sidewall into a filter cartridge opening of a filter support, and to sealingly engage the filter support at the filter cartridge opening.

7. The water filter cartridge of claim 6 , wherein said seal comprises a rounded annular region that extends radially outwardly from said sidewall and is spaced from said thin flange region.

8. The water filter cartridge of claim 7 , wherein said rounded annular region is positioned above said thin flange region, and wherein said rounded annular region is configured to sealingly engage the filter support at the filter cartridge opening.

9. The water filter cartridge of claim 1 , further comprising an upper filter pad disposed in said chamber below said upper inlet opening and above said filter media, and a lower filter pad disposed in said chamber above said at least one lower outlet opening and below said filter media.

10. The water filter cartridge of claim 9 , wherein said filter housing comprises a bottom wall in which said at least one lower outlet opening is formed, said bottom wall comprising an upwardly-facing surface that defines a lower extent of said chamber, and said bottom wall further comprising an array of spaced-apart upwardly-extending spikes having respective upper tips configured to engage a lower surface of said lower filter pad and support said lower filter pad above said upwardly-facing surface.

11. The water filter cartridge of claim 1 , wherein said filter media comprises separate top and bottom media layers of said granular mixture of agglomerated nanoparticles of anatase titania crystal titanium dioxide interspersed with granular activated charcoal, and an intermediate media layer of agglomerated nanoparticles of anatase titania crystal titanium dioxide disposed between said top and bottom media layers.

12. The water filter cartridge of claim 11 , wherein said top media layer comprises approximately 30 to 50 grams of said granular activated charcoal and approximately 2 to 3 grams of said nanoparticles of anatase titania crystal titanium dioxide, said bottom media layer comprises approximately 30 to 50 grams of said granular activated charcoal and approximately 2 to 3 grams of said nanoparticles of anatase titania crystal titanium dioxide, and said intermediate media layer consists of approximately 2 to 3 grams of said nanoparticles of anatase titania crystal titanium dioxide.

13. The water filter cartridge of claim 1 , wherein said granular activated charcoal comprises coconut charcoal.

14. A disposable water filter cartridge for use in a residential gravity-feed pitcher, said water filter cartridge comprising:

a filter housing configured for use in the residential gravity-feed pitcher, said filter housing comprising a sidewall having an annular upper region and said filter housing defining a chamber having an upper inlet opening and a lower outlet opening formed in a bottom wall, wherein said lower outlet opening comprises a plurality of spaced-apart lower outlet openings having a combined total area of about 0.03 to 0.04 square inches;

a filter media disposed in said chamber, said filter media comprising a granular mixture of at least 6 grams of agglomerated nanoparticles of anatase titania crystal titanium dioxide interspersed with less than or equal to 100 grams of granular activated charcoal;

a seal disposed around an outer periphery of said annular upper region, said seal comprising a flange region that extends radially outwardly from said sidewall and configured to flex upwardly upon insertion of the sidewall into a filter cartridge opening of a filter support;

an upper filter pad disposed in said chamber below said upper inlet opening and above said filter media; and

a lower filter pad disposed in said chamber above said lower outlet opening and below said filter media;

wherein said bottom wall comprises an upwardly-facing surface that defines a lower extent of said chamber, and an array of spaced-apart upwardly-extending spikes having respective upper tips configured to engage a lower surface of said lower filter pad and support said lower filter pad above said upwardly-facing surface; and

wherein said lower outlet opening is sized to limit a flow rate through said filter media to at least about 0.3 liters per minute.

15. The water filter cartridge of claim 14 , wherein said seal comprises a rounded annular region that extends radially outwardly from said sidewall and is spaced from said flange region.

16. The water filter cartridge of claim 15 , wherein said rounded annular region is positioned above said flange region, and wherein said rounded annular region is configured to sealingly engage the filter support at the filter cartridge opening.

17. The water filter cartridge of claim 14 , wherein said granular activated charcoal comprises coconut charcoal having a nominal grain size of about 40 to 45 mesh, and wherein said agglomerated nanoparticles of anatase titania crystal titanium dioxide have a nominal grain size of about 16 to 60 mesh.

18. The water filer cartridge of claim 14 , wherein said filter media comprises approximately 15 to 20 grams of said agglomerated nanoparticles of anatase titania crystal titanium dioxide and approximately 55 grams of said granular activated charcoal.

19. The water filter cartridge of claim 14 , wherein said agglomerated nanoparticles of anatase titania crystal titanium dioxide are substantially evenly distributed with said granular activated charcoal.

20. The water filter cartridge of claim 14 , wherein said filter media comprises separate top and bottom media layers of said granular mixture of agglomerated nanoparticles of anatase titania crystal titanium dioxide interspersed with granular activated charcoal, and an intermediate media layer of agglomerated nanoparticles of anatase titania crystal titanium dioxide disposed between said top and bottom media layers.