Aqueous alkali or alkaline treat and heat regeneration of NH.sub.4.sup.+ a d

• US 4,219,441 A
• Filed: 11/29/1977
• Issued: 08/26/1980
• Est. Priority Date: 12/01/1976
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kubota, Masayoshi, Koseki, Yasuo, Takahashi, Sankichi, Kubota, Shoji, Noshimura, Yusaku
• Primary Examiner(s): Konopka, P. E.
• Application Number:
  US05/855,702
• Time in Patent Office: 1,001 Days
• Field of Search: 252/412, 252/420, 210/38 R, 210/39, 210/40, 210/32
• US Class Current: 502/25
• CPC Class Codes: B01J 20/3408 of aluminosilicate molecular sieves

Abstract

A method of regenerating zeolite by heating wherein zeolite having adsorbed (NH₃ -N) in foul water has sodium hydroxide added thereto, the sodium hydroxide containing Na⁺ equivalent to NH₄⁺ adsorbed to the zeolite, water is added until the total quantity of the zeolite is submerged, and the resultant zeolite is heated at 400° C. for 30 minutes, whereby a regeneration rate of 90% is attained.

Claims

1. A method of regenerating a mixture of zeolite having adsorbed NH₄⁺ ion and active carbon having adsorbed organic matter, comprising the steps of:

submerging said mixture in an aqueous solution containing ions of at least one alkali metal thereby adding ions of said at least said one alkali metal to the mixture to make an aqueous mixture, wherein the mol ratio of said alkali ions to said NH₄⁺ ions is in the range of 1 to 1.5; and

heating the aqueous mixture with the added ions to within the temperature range of 150°

to 800°

C. to release NH₃ gas and decompose the organic matter without decomposing the zeolite.

2. The method of claim 1, wherein said step of adding adds ions of sodium.

3. The method of claim 1, wherein said step of adding adds ions to potassium.

4. The method of claim 1, wherein said step of heating is carried out within the range of 400°

to 800°

C.

5. The method of claim 1, wherein said step of adding adds the ions as alkali metal hydroxides.

6. The method of claim 1, wherein said step of adding adds the ions as alkali metal carbonates.

7. The method of claim 1, wherein said step of adding adds the ions as alkali metal bicarbonates.

8. The method of claim 1, wherein said step of adding adds the ions as a solution of a sodium containing salt of a strong acid together with a sodium salt that exhibits alkalinity.

9. The method of claim 1, wherein said step of adding adds the ions as a solution of a sodium containing salt of a strong acid together with sodium hydroxide.

10. A method of regenerating a mixture of zeolite having adsorbed NH₄⁺ ion and active carbon having adsorbed organic matter, comprisng the steps of:

submerging said mixture in an aqueous solution containing ions of at least one alkaline earth metal thereby adding ions of said at least one alkaline earth metal to the mixture to make an aqueous mixture, wherein the mol ratio of said alkaline earth metal ions to said NH₄⁺ ions is in the range of 1 to 1.5, and

heating the aqueous mixture with the added ions to within the temperature range of 150°

to 800°

C. to releast NH₃ gas and decompose the organic matter without decomposing the zeolite.

11. The method of claim 10, wherein said step of adding adds ions of magnesium.

12. The method of claim 10, wherein said step of adding adds ions of calcium.

13. The method of claim 10, wherein said step of heating is carried out within the range of 400°

°

to 800°

C.

14. The method of claim 10, wherein said ions are alkaline earth metal hydroxides.

15. The method of claim 10, wherein said ions are alkaline earth metal carbonates.

16. The method of claim 10, wherein said ions are alkaline earth metal bicarbonates.

17. A method of regenerating zeolite having adsorbed NH₄⁺ ions, comprising the steps of:

submerging said zeolite in an aqueous solution containing ions of at least one alkali metal thereby adding ions of at least one alkali metal to the zeolite to make an aqueous mixture, wherein the mol ratio of said alkali ions to said NH₄⁺ ions is in the range of 1 to 1.5; and

heating the aqueous mixture with the added ions to within the temperature range of 150°

to 800°

C. to release NH₃ gas without decomposing the zeolite.

18. The method of claim 17, wherein said step of adding adds ions of sodium.

19. The method of claim 17, wherein said step of adding adds ions of potassium.

20. The method of claim 17, wherein said step of heating is carried out within the range of 400°

to 800°

C.

21. The method of claim 17, wherein said step of adding adds the ions as alkali metal hydroxides.

22. The method of claim 17, wherein the step of adding adds the ions as alkali metal carbonates.

23. The method of claim 17, wherein said step of adding adds the ions as alkali metal bicarbonates.

24. The method of claim 17, wherein said step of adding adds the ions as a solution of a sodium containing salt of a strong acid together with a sodium salt that exhibits alkalinity.

25. The method of claim 17, wherein said step of adding adds the ions as a solution of a sodium containing salt of a strong acid together with sodium hydroxide.

26. A method of regenerating zeolite having adsorbed NH₄⁺ ions, comprising the steps of:

submerging said zeolite in an aqueous solution containing ions of at least one alkaline earth metal to the zeolite to make an aqueous mixture, wherein the mol ratio of said alkaline earth metal ions to said NH₄⁺ ions is in the range of 1 to 1.5; and

heating the aqueous mixture with added ions to within the temperature range of 150°

to 800°

C. to release NH₃ gas without decomposing the zeolite.

27. The method of claim 26, wherein said step of adding adds ions of magnesium.

28. The method of claim 26, wherein said step of adding adds ions of calcium.

29. The method of claim 26, wherein said step of heating is carried out within the range of 400°

to 800°

C.

30. The method of claim 26, wherein said ions are alkaline earth metal hydroxides.

31. The method of claim 26, wherein said ions are alkaline earth metal carbonates.

32. The method of claim 26, wherein said ions are alkaline earth metal bicarbonates.