Patent US4479877A successfully refreshed from Google Patents.
US4479877A
Expired / Lapsed
US
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Removal of nitrate from water supplies using a tributyl amine strong base anion exchange resin
Assignee: Environmental Protection Agency
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Filing: 1983-07-28
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Granted: 1984-10-30
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Expires: 2003-07-28
Abstract
Abstract The invention relates to a method for separating nitrate from waters containing a significant amount of sulfate ion. Nitrate removal is accomplished by passing the water to be treated through a bed of a strong-base anion exchange resin which is a tributyl amine derivative of a copolymer exemplified by styrene-divinyl benzene. The tributyl species has been found to have an unusually high selectivity for nitrate over sulfate and provides not only a high capacity for nitrate removal but also economies in regeneration due to the ability to operate with only a partially regenerated resin bed.
Inventors
- 👤 Gerald A. Guter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:47
CPC Classifications
B; B01; B01J; B01J41/00; B01J41/04; B01J41/05; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/903
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
63 words
A method for separating nitrate from a water containing sulfate and less than about 1000 ppm total dissolved solids, said method comprising passing the water through a bed of a particulate, strong-base anion exchange resin, said resin being a tributyl amine derivative of a copolymer of a monovinyl aryl compound and a polyolefinic cross-linking agent for adsorption of the nitrate onto said resin.
Claim 2
Independent Claim
63 words
A method for separating nitrate from a water containing sulfate and less than about 1000 ppm total dissolved solids, said method comprising passing the water through a bed of a particulate, strong-base anion exchange resin, said resin being a tributyl amine derivative of a copolymer of a monovinyl aryl compound and a polyolefinic cross-linking agent for adsorption of the nitrate onto said resin.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein said cross-linking agent is a polyvinyl aromatic hydrocarbon.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein said copolymer is a styrene-divinylbenzene copolymer.
Claim 5
Dependent Claim
22 words
The method of claim 1 wherein said water contains at least 50 ppm sulfate prior to contact with the ion exchange resin.
Claim 6
Dependent Claim
27 words
The method of claim 1 further comprising periodically washing said bed of particulate resin with an aqueous salt solution to regenerate said resin and permit its reuse.
Claim 7
Dependent Claim
13 words
The method of claim 5 wherein the salt in solution is sodium chloride.
Claim 8
Dependent Claim
37 words
The method of claim 5 wherein, prior to each periodic wash the nitrate adsorption step is continued through the sulfate breakthrough point and the resin bed is then washed for regeneration prior to the nitrate breakthrough point.
Claim 9
Dependent Claim
26 words
The method of claim 5 wherein each periodic wash is discontinued at a point where a substantial amount of nitrate remains adsorbed on said resin bed.
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) | 1987-10-30 | 1988-04-30 | 1988-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-30 | 1992-04-30 | 1992-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-30 | 1996-04-30 | 1996-10-30 | $7700.00 | Window Closed / Lapsed |