Removal of arsenic from water with oxidized metal coated pumice

• US 7,491,335 B2
• Filed: 05/13/2006
• Issued: 02/17/2009
• Est. Priority Date: 05/13/2005
• Status: Expired due to Fees

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Reddy, Pratap G., Turner, Charles D.
• Primary Examiner(s): Barry; Chester T
• Application Number:
  US11/433,638
• Publication Number:
  US 20070017871A1
• Time in Patent Office: 1,011 Days
• Field of Search: 210/660, 210/661, 210/663, 210/669, 210/688
• US Class Current: 210/660
• CPC Class Codes: B01J 20/0229 Compounds of Fe
• CPC Class Codes: B01J 20/06 comprising oxides or hydroxides of metals not provided for in group B01J20/04
• CPC Class Codes: B01J 20/10 comprising silica or silicate
• CPC Class Codes: B01J 20/3204 Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/3236 containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
• CPC Class Codes: B01J 2220/58 Use in a single column
• CPC Class Codes: B01J 2220/60 Use in several different columns
• CPC Class Codes: C02F 1/281 using inorganic sorbents
• CPC Class Codes: C02F 1/288 using composite sorbents, e.g. coated, impregnated, multi-layered
• CPC Class Codes: C02F 1/66 by neutralisation; pH adjustment for degassing C02F1/20; using ion-exchange C02F1/42; for flocculation or precipitation of suspended impurities C02F1/52; for removing dissolved compounds C02F1/58
• CPC Class Codes: C02F 1/72 by oxidation C02F1/4672 takes precedence
• CPC Class Codes: C02F 1/722 Oxidation by peroxides
• CPC Class Codes: C02F 1/76 with halogens or compounds of halogens C02F1/4674 takes precedence
• CPC Class Codes: C02F 1/78 with ozone C02F1/4672 takes precedence
• CPC Class Codes: C02F 2101/103 Arsenic compounds

Abstract

The current invention is concerned with methods and compositions for the removal of arsenic contamination from water. A method for binding As to oxidized metal coated pumice and method for making the same are disclosed. Water filters comprising oxidized metal coated pumice, such as oxidized iron coated pumice, are also provided.

Claims

1. A method of removing arsenic from water comprising the step of contacting the water with oxidized metal coated pumice, thereby reducing the level of arsenic in the water.

2. The method of claim 1, further comprising, prior to the step of contacting the water with the oxidized metal coated pumice, the additional step of exposing the water to an oxidizing agent.

3. The method of claim 1, further comprising, prior to the step of contacting the water with the oxidized metal coated pumice, the additional step of adjusting the pH of the water.

4. The method of claim 1, wherein the oxidized metal coated pumice is oxidized iron coated pumice.

5. The method of claim 1, wherein arsenic levels are reduced to less than 10 μ

g/L.

6. The method of claim 2, wherein the oxidizing agent converts As(III) to As(V).

7. The method of claim 3, wherein the water is adjusted to a pH of less than about 7.0.

8. The method of claim 1, wherein the water is drinking water.

9. The method of claim 8, wherein the drinking water is suitable for animal consumption.

10. The method in claim 9, wherein the drinking water is suitable for human consumption.

11. The method of claim 1, wherein the oxidized metal coated pumice is comprised in a column.

12. The method of claim 11, wherein the water is brought in contact with the iron coated pumice by passing the water through the column.

13. The method of claim 12, wherein the water is passed through the column(s) in an up flow direction.

14. The method of claim 12, wherein the water is passed through the column by gravity or by siphon.

15. The method of claim 12, wherein the water is passed through the column by a mechanical pump.

16. The method of claim 2, further comprising, prior to the step of contacting the water with the oxidized metal coated pumice, the step of adjusting the pH of the water.

17. The method of claim 2, wherein the water is adjusted to a pH of less than about 7.0.

18. The method of claim 5, wherein arsenic levels are reduced to 9 μ

g/L.

19. The method of claim 5, wherein arsenic levels are reduced to 4 μ

g/L.

20. The method of claim 1, wherein arsenic levels are reduced up to 92%.

21. The method of claim 1, wherein arsenic levels are reduced up to 98%.

22. The method of claim 7, wherein the water is adjusted to a pH of about 5.5 to 6.0.

23. The method of claim 7, wherein the water is adjusted to a pH of about 5.0.

24. The method of claim 7, wherein the water is adjusted to a pH of about 4.0.