US4305824A
Expired / Lapsed
US
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Cellulose derivative reverse osmosis membrane
Assignee: Toray Industries Inc
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Filing: 1980-02-22
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Granted: 1981-12-15
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Expires: 2000-02-22
Abstract
Abstract Cellulose derivative reverse osmosis membrane containing tetracarboxylic acid and mono- or divalent carboxylic acid.
Inventors
- 👤 Tadahiro Uemura
- 👤 Masaru Kurihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:55
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/08; B01D71/12; B01D71/14; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0011; B01D71/16; B01D71/18; B01D71/22; C; C08; C08K; C08K5/00; C08K5/04; C08K5/09; C08K5/092; B01D61/00; B01D61/02; B01D61/025; B29; B29K; B29K2001/00; B29K2001/08; B29K2001/12
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
195 words
A reverse osmosis membrane comprising a cellulose derivative selected from the group consisting of cellulose ether or cellulose ester prepared from a casting solution containing a tetracarboxylic acid having by the formula: R--(CO.sub.2 H).sub.4 wherein R is a member of the group consisting of a tetravalent aliphatic or alicyclic organic radical having from 2 to 10 carbon atoms, said membrane having not less than about 3×10 -10 g 3 /cm 7 .sec 2 .atm 3 of A 3 /B and not more than about 0.2 voids per 0.844 mm 2 , wherein A is the water permeation coefficient (g/cm 2 .sec.atm) and equal to F 1 /(ΔP-Δπ), where F 1 is the product water flow through the membrane (g/cm 2 .sec), Δ P is the applied pressure differential(atm) and Δ π is the osmotic pressure differential(atm); and B is the salt permeation coefficient (cm/sec) and is equal to F 2 /(C 1 -C 2 ), wherein F 2 is the salt permeation through the membrane (g/cm 2 .sec), C 1 is the salt concentration in the feed water (g/cm 3 ) and C 2 is the salt concentration in the product water (g/cm 3 ).
Claim 2
Dependent Claim
195 words
A reverse osmosis membrane comprising a cellulose derivative selected from the group consisting of cellulose ether or cellulose ester prepared from a casting solution containing a tetracarboxylic acid having by the formula: R--(CO.sub.2 H).sub.4 wherein R is a member of the group consisting of a tetravalent aliphatic or alicyclic organic radical having from 2 to 10 carbon atoms, said membrane having not less than about 3×10 -10 g 3 /cm 7 .sec 2 .atm 3 of A 3 /B and not more than about 0.2 voids per 0.844 mm 2 , wherein A is the water permeation coefficient (g/cm 2 .sec.atm) and equal to F 1 /(ΔP-Δπ), where F 1 is the product water flow through the membrane (g/cm 2 .sec), Δ P is the applied pressure differential(atm) and Δ π is the osmotic pressure differential(atm); and B is the salt permeation coefficient (cm/sec) and is equal to F 2 /(C 1 -C 2 ), wherein F 2 is the salt permeation through the membrane (g/cm 2 .sec), C 1 is the salt concentration in the feed water (g/cm 3 ) and C 2 is the salt concentration in the product water (g/cm 3 ).
Claim 3
Dependent Claim
27 words
The reverse osmosis membrane of claim 1, wherein said cellulose derivative is a cellulose acetate having an acetyl content of about 39.8% to about 43.2% by weight.
Claim 4
Dependent Claim
33 words
The reverse osmosis membrane of claim 1, wherein the cellulose derivative is a member selected from the group consisting of cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, methyl cellulose and ethyl cellulose.
Claim 5
Dependent Claim
32 words
The reverse osmosis membrane of claim 1, wherein the amount of tetracarboxylic acid is from about 1 to about 20 parts by weight per 10 parts by weight of the cellulose derivative.
Claim 6
Dependent Claim
32 words
The reverse osmosis membrane of claim 1, wherein the tetracarboxylic acid is selected from the group consisting of butanetetracarboxylic acid, ethylene tetracarboxylic acid, cyclopropanetetracarboxylic acid, cyclobutanetetracarboxylic acid, cyclopentanetracarboxylic acid and furantetracarboxylic acid.
Claim 7
Dependent Claim
14 words
The reverse osmosis membrane of claim 5 wherein the tetracarboxylic acid is 1,2,3,4-butanetetracarboxylic acid.
Claim 8
Dependent Claim
23 words
The reverse osmosis membrane of claim 1, which further contains a member selected from the group consisting of monocarboxylic acid and dicarboxylic acid.
Claim 9
Dependent Claim
36 words
The reverse osmosis membrane of claim 7, wherein the mole fraction of the member based on the total mols of the member and tetracarboxylic acid contained in the casting solution is not more than about 0.55.
Claim 10
Dependent Claim
18 words
The reverse osmosis membrane of claim 8, wherein said mole fraction is from about 0.20 to about 0.40.
Claim 11
Dependent Claim
15 words
The reverse osmosis membrane of claim 7, wherein the dicarboxylic acid is a maleic acid.
References Cited (Backward Citations)
US3497072A
Cited
US3657401A
Cited
USRE27319E
Cited
US3789993A
Cited
US3792135A
Cited
JPS5032080A
Cited
US4239545A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-12-14 | 1985-06-15 | 1985-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-14 | 1989-06-15 | 1989-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-14 | 1993-06-15 | 1993-12-15 | $7700.00 | Window Closed / Lapsed |