US4711719A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of crack-free semi-permeable inorganic membranes
Assignee: Energy Research Centre of the Netherlands
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Filing: 1984-09-05
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Granted: 1987-12-08
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Expires: 2004-09-05
Abstract
Abstract A process for the production of dry, crack-free mechanically and chemically stable, thin, semi-permeable, inorganic membranes by coating a microporous support of sintered metal oxide or metal hydroxide with a stable sol of Boehemite particles and subsequently drying and heating the coated support.
Inventors
- 👤 Adriaan F. M. Leenaars
- 👤 Anthonie J. Burggraaf
- 👤 Klass Keizer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:03
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0039; B01D67/0048; B01D71/00; B01D71/02; B01D71/024; B01D71/025; C; C04; C04B; C04B41/00; C04B41/009; C04B41/45; C04B41/50; C04B41/5025; C04B41/80; C04B41/81; C04B41/85; C04B41/87; B01D2323/00; B01D2323/08; B01D2323/081; B01D2323/219; B01D2323/225
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
166 words
A process for the production of dry, crack-free mechanically and chemically stable, semi-permeable inorganic membranes by coating a microporous support of sintered α-Al 2 O 3 by contacting the support with a sol containing particles of Al 2 O 3 and drying and heating the coated support, characterized in that (a) the support has a thickness from 50μ to 5 mm; (b) the sol comprises as Al 2 O 3 particles Boehemite particles with a size of from 3 nm to 2μ, dispersed in water in a concentration from 0.01 to 25% by weight, the water also containing HNO 3 or HClO 4 in a concentration of 0.01 to 0.20 mol per mol Boehemite; (c) said support is immersed in a dry state in said sol for from 1 to 5 seconds; and (d) said contacted support after being dried in air is heated to a temperature of at least 390° C. and at most 1500° C., wherein said membrane is less than 20μ in thickness.
Claim 2
Dependent Claim
166 words
A process for the production of dry, crack-free mechanically and chemically stable, semi-permeable inorganic membranes by coating a microporous support of sintered α-Al 2 O 3 by contacting the support with a sol containing particles of Al 2 O 3 and drying and heating the coated support, characterized in that (a) the support has a thickness from 50μ to 5 mm; (b) the sol comprises as Al 2 O 3 particles Boehemite particles with a size of from 3 nm to 2μ, dispersed in water in a concentration from 0.01 to 25% by weight, the water also containing HNO 3 or HClO 4 in a concentration of 0.01 to 0.20 mol per mol Boehemite; (c) said support is immersed in a dry state in said sol for from 1 to 5 seconds; and (d) said contacted support after being dried in air is heated to a temperature of at least 390° C. and at most 1500° C., wherein said membrane is less than 20μ in thickness.
Claim 3
Dependent Claim
28 words
A process according to claim 1, characterized in that the sintered α-Al 2 O 3 is used as support, having a pore size of from 0.10μ to 0.50μ.
Claim 4
Dependent Claim
20 words
A process according to claim 1, characterized in that the support has a pore size of from 0.12μ to 0.34μ.
Claim 5
Dependent Claim
36 words
A process according to claim 1, characterized in that the sol contains 0.01 to 0.20 mol HClO 4 per mol Boehemite and that the immersed support is dried and heated at 500° C. for 24 hours.
Claim 6
Dependent Claim
36 words
A process according to claim 1, characterized in that the sol contains 0.03 to 0.11 mol HClO 4 per mol Boehemite and that the immersed support is dried and heated at 500° C. for 24 hours.
Claim 7
Dependent Claim
52 words
A process according to claim 1 characterized in that the sol contains 3% by weight Boehemite and that the time of contact of the dry support and the sol is adjusted to from 1 to 5 seconds and thereafter dried and heated at a temperature of from 390° C. to 1500° C.
Claim 8
Dependent Claim
10 words
An inorganic membrane produced by the process of claim 1.
References Cited (Backward Citations)
FR1440105A
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US3434912A
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FR2000803A1
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FR2150390A1
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US3944658A
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FR2230601A1
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US3923654A
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US4412921A
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US4251377A
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US4473476A
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EP0040282A1
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EP0092840A1
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-12-07 | 1991-06-08 | 1991-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-07 | 1995-06-08 | 1995-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-07 | 1999-06-08 | 1999-12-08 | $7700.00 | Window Closed / Lapsed |