US4005012A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semipermeable membranes and the method for the preparation thereof
Assignee: United States Department of the Interior
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Filing: 1975-09-22
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Granted: 1977-01-25
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Expires: 1995-09-22
Abstract
Abstract Semipermeable membranes which are useful in reverse osmosis processes are prepared by forming a polymeric ultra-thin film which possesses semipermeable properties on a microporous support. An example of the composite semipermeable membrane comprising an ultra-thin film formed by contacting an amine modified polyepihalohydrin with a polyfunctional agent and depositing this film on one surface of a microporous substrate.
Inventors
- 👤 Wolfgang J. Wrasidlo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:28
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/40; C08G18/48; C08G18/50; C08G18/5021; C08G18/5024; B; B01; B01D; B01D69/00; B01D69/12; B01D69/125; B01D71/00; B01D71/06; B01D71/58; B01D71/60; B01D71/601
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
107 words
In a process for desalination of saline water by reverse osmosis comprising contacting the saline water under pressure with a reverse osmosis membrane, the improvement comprising using as the reverse osmosis membrane a composite semipermeable membrane prepared by a method comprising the steps of: a. treating a microporous substrate with an aqueous solution of an amine modified polyepihalohydrin, b. immersing the resultant coated microporous substrate in a solution of a polyfunctional agent capable of reacting with the amine groups of said amine modified polyepihalohydrin to form an ultra-thin film on one surface of said microporous support, and c. drying said composite semipermeable membrane at an elevated temperature.
Claim 2
Dependent Claim
107 words
In a process for desalination of saline water by reverse osmosis comprising contacting the saline water under pressure with a reverse osmosis membrane, the improvement comprising using as the reverse osmosis membrane a composite semipermeable membrane prepared by a method comprising the steps of: a. treating a microporous substrate with an aqueous solution of an amine modified polyepihalohydrin, b. immersing the resultant coated microporous substrate in a solution of a polyfunctional agent capable of reacting with the amine groups of said amine modified polyepihalohydrin to form an ultra-thin film on one surface of said microporous support, and c. drying said composite semipermeable membrane at an elevated temperature.
Claim 3
Dependent Claim
46 words
The process of claim 1 in which preparation of the composite semipermeable membrane is further characterized in that said membrane is coated with a water soluble organic polymer and thereafter heated at an elevated temperature to form a protective coating on the surface of the membrane.
Claim 4
Dependent Claim
11 words
The process of claim 1 in which the polyepihalohydrin is polyepichlorohydrin.
Claim 5
Dependent Claim
14 words
The process of claim 1 in which the polyepihalohydrin is modified with ethylene diamine.
Claim 6
Dependent Claim
13 words
The process of claim 1 in which the polyfunctional agent is isophthaloyl chloride.
Claim 7
Dependent Claim
22 words
The process of claim 1 in which the composite semipermeable membrane is dried at a temperature of about 50° to 125° C.
Claim 8
Dependent Claim
15 words
The process of claim 2 in which the water soluble organic polymer is polyvinyl alcohol.
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) | 1980-01-25 | 1980-07-26 | 1981-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-01-25 | 1984-07-26 | 1985-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-01-25 | 1988-07-26 | 1989-01-25 | $7700.00 | Window Closed / Lapsed |