US4828708A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semipermeable membranes
Assignee: Desalination Systems Inc
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Filing: 1987-09-28
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Granted: 1989-05-09
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Expires: 2007-09-28
Abstract
Abstract A reverse osmosis membrane with excellent nitrate rejection that is particularly suitable for point-of-use drinking water purposes. The reverse osmosis membrane is a composite material comprising a porous support layer and an ultrathin polyamide desalinizing layer which is the interfacial condensation reaction product of (a) meta-phenylenediamine and (b) a mixture of a major portion of isophthaloyl chloride and a minor proportion of trimesoyl chloride.
Inventors
- 👤 Donald T. Bray
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:19
CPC Classifications
C; C08; C08G; C08G69/00; C08G69/02; C08G69/26; C08G69/265; B; B01; B01D; B01D69/00; B01D69/12; B01D69/125; B01D69/1251; B01D71/00; B01D71/06; B01D71/56
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
71 words
A sheet-like composite membrane suitable for separating water from aqueous solutions containing nitrate comprising a microporous support layer and, supported thereon, a water permeable, interfacially polymerized, ultrathin polyamide desalinizing layer, said desalinizing layer comprising the interfacial condensation reaction product of (a) a bifunctional monocyclic aromatic amine; and (b) a mixture containing at least about 80 % by weight of isophthaloyl chloride and at least about 5% by weight of trimesoyl chloride.
Claim 2
Dependent Claim
71 words
A sheet-like composite membrane suitable for separating water from aqueous solutions containing nitrate comprising a microporous support layer and, supported thereon, a water permeable, interfacially polymerized, ultrathin polyamide desalinizing layer, said desalinizing layer comprising the interfacial condensation reaction product of (a) a bifunctional monocyclic aromatic amine; and (b) a mixture containing at least about 80 % by weight of isophthaloyl chloride and at least about 5% by weight of trimesoyl chloride.
Claim 3
Dependent Claim
13 words
A composite membrane according to claim 1 wherein said aromatic amine is meta-phenylenediamine.
Claim 4
Dependent Claim
38 words
A composite membrane according to claim 1 wherein said desalinizing layer is the reaction produce of meta-phenylenediamine and a mixture of about 80 to 90 % isophthaloyl chloride and about 10 to 20% by weight of trimesoyl chloride.
Claim 5
Dependent Claim
91 words
A process for the preparation of a composite reverse osmosis membrane which is suitable for separating water from aqueous solutions containing nitrate comprising the steps of: (a) coating a porous support with a liquid layer comprising an aqueous solution containing a bifunctional monocyclic aromatic amine; (b) contacting the said liquid layer with a non-polar liquid organic solvent containing, dissolved therein, a mixture containing at least about 90 % by weight of isophthaloyl chloride and at least about 5% by weight of trimesoyl chloride; and (c) drying the product of step (b).
Claim 6
Dependent Claim
91 words
A process for the preparation of a composite reverse osmosis membrane which is suitable for separating water from aqueous solutions containing nitrate comprising the steps of: (a) coating a porous support with a liquid layer comprising an aqueous solution containing a bifunctional monocyclic aromatic amine; (b) contacting the said liquid layer with a non-polar liquid organic solvent containing, dissolved therein, a mixture containing at least about 90 % by weight of isophthaloyl chloride and at least about 5% by weight of trimesoyl chloride; and (c) drying the product of step (b).
Claim 7
Dependent Claim
13 words
A method according to claim 4 wherein said bifunctional aromatic amine is meta-phenylenediamine.
Claim 8
Dependent Claim
26 words
A method according to claim 5 wherein between about 10 and about 20 weight % trimesoyl chloride is present based upon total weight of acyl chloride.
Claim 9
Dependent Claim
77 words
A process for the treatment of an aqueous solution containing nitrate to substantially reduce the nitrate content thereof by contacting the aqueous nitrate solution under pressure with a reverse osmosis membrane, wherein the improvement comprises employing a membrane which includes the interfacial condensation reaction product of: (a) a bifunctional monocyclic aromatic amine; and (b) a mixture containing at least about 80 % by weight of isophthaloyl chloride and at least about 5% by weight of trimesoyl chloride.
Claim 10
Dependent Claim
77 words
A process for the treatment of an aqueous solution containing nitrate to substantially reduce the nitrate content thereof by contacting the aqueous nitrate solution under pressure with a reverse osmosis membrane, wherein the improvement comprises employing a membrane which includes the interfacial condensation reaction product of: (a) a bifunctional monocyclic aromatic amine; and (b) a mixture containing at least about 80 % by weight of isophthaloyl chloride and at least about 5% by weight of trimesoyl chloride.
Claim 11
Dependent Claim
39 words
A process according to claim 7 wherein said desalinizing layer is the reaction product of meta-phenylenediamine and a mixture of about 80 to 90 weight % of isophthaloyl chloride and about 10 to 20 weight % of trimesoyl chloride.
References Cited (Backward Citations)
US4606943A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-08 | 1992-11-07 | 1993-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-08 | 1996-11-07 | 1997-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-08 | 2000-11-07 | 2001-05-09 | $7700.00 | Window Closed / Lapsed |