US4806264A
Expired / Lapsed
US
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Method of selectively removing selenium ions from an aqueous solution
Assignee: United States Department of the Interior
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Filing: 1987-09-01
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Granted: 1989-02-21
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Expires: 2007-09-01
Abstract
Abstract A method of selectively removing selenium ions from an aequeous solution containing selenium ions comprises contacting the solution with an amount of ferrous ion effective to reduce the selenium ions to elemental selenium. The contacting is preferably conducted at a pH of about 9 and the ferrous ions are preferably provided in situ in the form of ferrous hydroxide. The method may further comprise removing ferric oxides to which the ferrous ions are oxidized, these ferric oxides containing the elemental selenium produced by the reduction of the selenium ions, and separating the ferric oxides from the elemental selenium by adding a strong acid thereto.
Inventors
- 👤 Andrew P. Murphy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 21:34
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/70; C01; C01B; C01B19/00; C01B19/02; Y; Y10; Y10S; Y10S210/00; Y10S210/902
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
54 words
A method of selectively removing selenium ions from an aqueous solution, wherein said selenium ions are selected from the group consisting of selenite ions and selenate ions comprising contacting said solution at a pH of about 8 to 10 with an amount of ferrous ions effective to reduce said selenium ions to elemental selenium.
Claim 2
Independent Claim
54 words
A method of selectively removing selenium ions from an aqueous solution, wherein said selenium ions are selected from the group consisting of selenite ions and selenate ions comprising contacting said solution at a pH of about 8 to 10 with an amount of ferrous ions effective to reduce said selenium ions to elemental selenium.
Claim 3
Dependent Claim
31 words
The method of claim 1, wherein said ferrous ions are provided in the form of ferrous hydroxide and said ferrous ions are oxidized to magnetic ferric oxides after the contacting step.
Claim 4
Dependent Claim
14 words
The method of claim 2, wherein said magnetic ferric oxides contain said elemental selenium.
Claim 5
Dependent Claim
16 words
The method of claim 3, further comprising magnetically removing said ferric oxides containing said elemental selenium.
Claim 6
Dependent Claim
21 words
The method of claim 4, further comprising separating said ferric oxides from said elemental selenium by adding a strong acid thereto.
Claim 7
Dependent Claim
13 words
The method of claim 2, wherein said ferrous hydroxide is generated in situ.
Claim 8
Dependent Claim
24 words
The method of claim 6, wherein said ferrous hydroxide is generated by providing a ferrous salt and an alkali metal hydroxide to said solution.
Claim 9
Dependent Claim
27 words
The method of claim 2, wherein said ferrous hydroxide is generated by adding carbonyl iron to the aqueous solution at a pH of about 8 to 10.
Claim 10
Dependent Claim
12 words
The method of claim 8, wherein the aqueous solution is ground water.
Claim 11
Dependent Claim
11 words
The method of claim 1, wherein the pH is about 9.
Claim 12
Dependent Claim
34 words
The method of claim 1, wherein said ferrous ions and said selenium ions are contacted in a proportion of at least about nine molar equivalent of ferrous ions per molar equivalent of selenium ions.
Claim 13
Dependent Claim
27 words
The method of claim 7, wherein said ferrous ions are present in a molar equivalent amount in excess of the molar equivalent amount of the selenium ions.
Claim 14
Dependent Claim
21 words
The method of claim 1, wherein said contacting step is conducted at a temperature of about 10 to 35 degrees C.
Claim 15
Dependent Claim
15 words
The method of claim 13, wherein said temperature is about 17 to 30 degrees C.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
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