US4051316A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of heavy metal ions from aqueous solutions with insoluble crosslinked-starch-xanthates
Assignee: United States Department of Agriculture
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Filing: 1976-06-14
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Granted: 1977-09-27
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Expires: 1996-06-14
Abstract
Abstract An insoluble alkali metal-magnesium starch-xanthate composition is prepared which is capable of removing most heavy metal ions from aqueous solutions. Concentrations of heavy metal ions contained in several industrial effluents were reduced to below the most stringent aqueous discharge limits.
Inventors
- 👤 Robert E. Wing
- 👤 William M. Doane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:34
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/28; C02F1/286; C08; C08B; C08B31/00; C08B31/02; C08B31/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
81 words
A composition useful for removing heavy metal ions from aqueous solutions comprising an alkali metal-magnesium salt of crosslinked-starch-xanthate having a degree of crosslinking (DCL) such that said salt exhibits a degree of swelling in water at 95° C. of from 65% to 450%, wherein said crosslinking occurs between the starch molecules of said salt through the hydroxyl oxygens of said molecules, and having said magnesium present in an amount ranging from about 0.5% to about 12.0% by weight of said salt.
Claim 2
Dependent Claim
81 words
A composition useful for removing heavy metal ions from aqueous solutions comprising an alkali metal-magnesium salt of crosslinked-starch-xanthate having a degree of crosslinking (DCL) such that said salt exhibits a degree of swelling in water at 95° C. of from 65% to 450%, wherein said crosslinking occurs between the starch molecules of said salt through the hydroxyl oxygens of said molecules, and having said magnesium present in an amount ranging from about 0.5% to about 12.0% by weight of said salt.
Claim 3
Dependent Claim
13 words
A composition as described in claim 1 having the following general structure: ##STR5##
Claim 4
Dependent Claim
18 words
A composition as described in claim 1 which exhibits a degree of swelling of from 65% to 75%.
Claim 5
Dependent Claim
18 words
A composition as described in claim 1 having a xanthate degree of substitution of from 0.1 to 1.
Claim 6
Dependent Claim
13 words
A composition as described in claim 1 wherein said alkali metal is sodium.
Claim 7
Dependent Claim
13 words
A composition as described in claim 1 wherein said alkali metal is potassium.
References Cited (Backward Citations)
US3385719A
Cited
US3947354A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-26 | 1981-03-28 | 1981-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-26 | 1985-03-28 | 1985-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-26 | 1989-03-28 | 1989-09-27 | $7700.00 | Window Closed / Lapsed |