US4256587A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Siliceous adsorbent for heavy metals
Assignee: United States Department of the Interior
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Filing: 1979-11-27
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Granted: 1981-03-17
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Expires: 1999-11-27
Abstract
Abstract A low cost, effective method for removing heavy metal ions from aqueous solution which utilizes a porous, high surface-to-weight ratio siliceous adsorbent comprises the steps of activating the siliceous adsorbent, which is preferably a kaolin clay leach residue, with a basic salt of an alkali metal to incorporate alkali ions into the siliceous adsorbent and contacting the heavy metal ion-containing solution with the activated adsorbent whereby the heavy metal ions exchange with the alkali ions to remove the heavy metal ions from solution. The heavy metal ion loaded adsorbent may be stripped for subsequent reuse or, alternatively, utilized for flux in base metal smelting and the like.
Inventors
- 👤 Thomas G. Carnahan
- 👤 Charles M. Flynn, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:47
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/28; C02F1/281; B; B01; B01J; B01J20/00; B01J20/02; B01J20/10
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
102 words
A method for removing heavy metal ions from aqueous solution comprising the steps of: (a) activating a high surface-to-weight ratio, porous siliceous adsorbent material, from the group consisting of kaolin leach residue, diatomaceous earth, fly ash and silica flour, with alkali metal ions by contacting said siliceous adsorbent material with an aqueous solution of the basic salt of an alkali metal; and (b) contacting said activated siliceous adsorbent material with said heavy metal ion-containing aqueous solution; whereby said heavy metal ions exchange with said alkali metal ions to decrease the concentration of heavy metal ions in said heavy metal ion-containing aqueous solution.
Claim 2
Independent Claim
102 words
A method for removing heavy metal ions from aqueous solution comprising the steps of: (a) activating a high surface-to-weight ratio, porous siliceous adsorbent material, from the group consisting of kaolin leach residue, diatomaceous earth, fly ash and silica flour, with alkali metal ions by contacting said siliceous adsorbent material with an aqueous solution of the basic salt of an alkali metal; and (b) contacting said activated siliceous adsorbent material with said heavy metal ion-containing aqueous solution; whereby said heavy metal ions exchange with said alkali metal ions to decrease the concentration of heavy metal ions in said heavy metal ion-containing aqueous solution.
Claim 3
Dependent Claim
27 words
A method as claimed in claim 1, wherein said heavy metal ion containing aqueous solution has a pH in the range from about 2.0 to about 10.0.
Claim 4
Independent Claim
23 words
A method as claimed in claims 1 or 2, wherein said alkali metal is selected from the group consisting of sodium and potassium.
Claim 5
Dependent Claim
45 words
A method as claimed in claim 3, wherein said basic salt of said alkali metal is selected from the group consisting of NaOH, Na 2 CO 3 , Na 2 SiO 3 , KOH, K 2 CO 3 , and K 2 SiO 3 .
Claim 6
Dependent Claim
40 words
A method as claimed in claim 4, wherein said heavy metal ions are stripped from said siliceous adsorbent by a chemical stripping agent selected from the group consisting of mineral acids, sodium cyanide and the sodium salts of ethylenediaminetetraacetic acid.
Claim 7
Dependent Claim
21 words
A method as claimed in claim 5, wherein said alkali metal is selected from the group consisting of sodium and potassium.
Claim 8
Independent Claim
21 words
A method as claimed in claims 1 or 2, wherein said siliceous adsorbent includes at least 90 percent SiO 2 .
Claim 9
Independent Claim
21 words
A method as claimed in claims 1 or 2, wherein said siliceous adsorbent includes at least 98 percent SiO 2 .
Claim 10
Independent Claim
27 words
A method as claimed in claims 1 or 2, wherein said siliceous adsorbent is the kaolin leach residue remaining after the extraction of aluminum from kaolin clay.
Claim 11
Independent Claim
47 words
A method as claimed in claims 1 or 2, further including the steps of stripping said heavy metal ions from said siliceous adsorbent and regenerating said stripped siliceous adsorbent by contacting said stripped siliceous adsorbent with an aqueous solution of the basic salt of an alkali metal.
Claim 12
Independent Claim
27 words
A method as claimed in claims 1 or 2, wherein said siliceous adsorbent material has a surface-to-weight ratio of at least about 100 square meters per gram.
Claim 13
Dependent Claim
25 words
A method as claimed in claim 11, wherein said siliceous adsorbent is the kaolin leach residue remaining after the extraction of aluminum from kaolin clay.
References Cited (Backward Citations)
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Cited
US3374182A
Cited
US3882018A
Cited
US4051026A
Cited
US4167481A
Cited
US4100065A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-16 | 1984-09-15 | 1985-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-16 | 1988-09-15 | 1989-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-16 | 1992-09-15 | 1993-03-17 | $7700.00 | Window Closed / Lapsed |