US4576929A
Expired / Lapsed
US
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Active carbon fibers as adsorbent for water purification
Assignee: Teijin Ltd
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Filing: 1984-12-18
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Granted: 1986-03-18
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Expires: 2004-12-18
Abstract
Abstract Active carbon fibers derived from acrylic fibers and having a BET specific surface area (SA) of 800 to 2,000 m 2 /g, a pore volume (Vp) to (SA) ratio, i.e., (Vp)/(SA), of from 5×10 -4 to 14.5×10 -4 , and a methylene blue adsorption rate constant of not less than 5×10 -1 sec -1 , and a filter adsorption unit for water purification using said active carbon fibers; the unit is useful to remove compounds having a wide range of molecular weights from an aqueous liquid.
Inventors
- 👤 Kenji Shimazaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:07
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/28; C02F1/283; D; D01; D01F; D01F9/00; D01F9/08; D01F9/12; D01F9/14; D01F9/32
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
55 words
Active carbon fibers derived from acrylic fibers and having a BET specific surface area (SA) of from 800 to 2,000 m 2 /g, a ratio of pore volume (Vp) to (SA) of from 5×10 -4 to 14.5×10 -4 , and a methylene blue adsorption rate constant of not less than 5×10 -1 sec -1 .
Claim 2
Dependent Claim
55 words
Active carbon fibers derived from acrylic fibers and having a BET specific surface area (SA) of from 800 to 2,000 m 2 /g, a ratio of pore volume (Vp) to (SA) of from 5×10 -4 to 14.5×10 -4 , and a methylene blue adsorption rate constant of not less than 5×10 -1 sec -1 .
Claim 3
Dependent Claim
19 words
Active carbon fibers as claimed in claim 1, wherein the length of the fibers is longer than 2 mm.
Claim 4
Dependent Claim
23 words
Active carbon fibers as claimed in claim 1, wherein said acrylic fiber comprising a polymer containing at least 60% by weight of acrylonitrile.
Claim 5
Dependent Claim
37 words
Active carbon fibers as claimed in claim 1, wherein said active carbon fibers are obtained by preoxidizing acrylic fibers, activating the thus obtained preoxidized fibers and subjecting the thus obtained active carbon fibers to an acid treatment.
Claim 6
Dependent Claim
24 words
Active carbon fibers as claimed in claim 4, wherein the ash content of the activative carbon fibers is from 2.5 to 15% by weight.
Claim 7
Dependent Claim
43 words
Active fibers as claimed in claim 4, wherein the acid used in said acid treatment is selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, oxalic acid, malonic acid, succinic acid, formic acid, acetic acid and propionic acid.
Claim 8
Dependent Claim
27 words
Active carbon fibers as claimed in claim 4, wherein said acid treatment is conducted by immersing the active carbon fibers in an aqueous solution of an acid.
Claim 9
Dependent Claim
25 words
Active carbon fibers as claimed in claim 6, wherein said aqueous solution has a concentration of an acid of from 0.1 to 40% by weight.
Claim 10
Dependent Claim
20 words
Active carbon fibers as claimed in claim 4, wehrein said acid treatment is conducted at from 5° to 100° C.
Claim 11
Dependent Claim
20 words
Active carbon fibers as claimed in claim 4, wherein said acid treatment is conducted for from 5 to 180 minutes.
Claim 12
Dependent Claim
32 words
Active carbon fibers as claimed in claim 1, wherein said active carbon fibers have silver in an amount of from 50 to 17,000 ppm based on the weight of active carbon fibers.
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) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |