Patent US5069800A successfully refreshed from Google Patents.
US5069800A
Expired / Lapsed
US
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Chemical process for the denitrification of water
Assignee: United States Department of the Interior
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Filing: 1990-08-22
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Granted: 1991-12-03
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Expires: 2010-08-22
Abstract
Abstract A chemical process for the denitrification of water comprising treating water with a metal sufficiently electropositive to decompose the water while regulating the pH within a range effective to permit efficient reduction of nitrate ion. The pH is regulated with alkali in a manner that avoids metal oxide formation and loss of metal by decomposition of water and results in the selective reduction of nitrate ion in the presence of sulfate and chloride ions.
Inventors
- 👤 Andrew P. Murphy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 13:09
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/70; C02F1/705; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
59 words
A chemical process for denitrification of water containing nitrate, sulfate and chloride ions by selectively reducing the nitrate ions comprising: regulating of said water between about 8.5 to about 11 with an alkali and adding a metal sufficiently electropositive to permit reduction of the nitrate ions to nitrogen or ammonia without consuming said metal by decomposing water to hydrogen.
Claim 2
Dependent Claim
59 words
A chemical process for denitrification of water containing nitrate, sulfate and chloride ions by selectively reducing the nitrate ions comprising: regulating of said water between about 8.5 to about 11 with an alkali and adding a metal sufficiently electropositive to permit reduction of the nitrate ions to nitrogen or ammonia without consuming said metal by decomposing water to hydrogen.
Claim 3
Dependent Claim
10 words
The process of claim 1, wherein the metal is aluminum.
Claim 4
Dependent Claim
19 words
The process of claim 1, wherein oxygen or air is introduced to control surface oxide formation on the aluminum.
Claim 5
Dependent Claim
16 words
The process according to claim 3 wherein the alkali is selected from sodium hydroxide or lime.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-02 | 1995-06-03 | 1995-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-02 | 1999-06-03 | 1999-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-02 | 2003-06-03 | 2003-12-03 | $7700.00 | Window Closed / Lapsed |