US3720626A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Elution process for the regeneration of spent activated carbon
Assignee: Suez International SAS
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Filing: 1970-06-19
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Granted: 1973-03-13
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Expires: 1990-06-19
Abstract
Abstract Improvement in the process for the regeneration of spent activated carbon combining an aqueous alkaline solution and an organic solvent, such as a lower alcohol. The spent carbon is first contacted in a column under practically static conditions, and at between 25* and 90*C for 30 minutes to 2 hours with an aqueous alkaline solution, preferably 0.5 to 25 percent by weight sodium hydroxide. An alkaline treatment prepares the elution action of the solvent. The solvent is a lower alcohol, preferably isopropanol combined with water. The solvent is then removed by steam and the carbon is regenerated by an acid treatment. Complete regeneration is obtained.
Inventors
- 👤 J Benzaria
- 👤 C Zundel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:24
CPC Classifications
C; C01; C01B; C01B32/00; C01B32/30; C01B32/354; C01B32/36
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
173 words
A process for regenerating spent vegetable or mineral activated carbon, comprising (a) subjecting said carbon to an alkaline treatment by contacting said spent carbon in a column with an aqueous alkaline solution having a flow velocity of zero to less than 1 m/hour through said column at a temperature of about 20* to 130*C., for a period of about 30 minutes to 2 hours to change the polarity of the carbon and condition it for solvent displacement of the adsorbed substances on said carbon, (b) eluting said adsorbed organic substances by solubilizing and displacing said adsorbed organic substances on said carbon with an aqueous organic solvent eluting solution, which is passed through said carbon in said column at a higher flow velocity than said alkaline solvent, and wherein said organic solvent is selected from the group consisting of lower alcohols, acetone and dichloroethane, (c) removing said eluting solvent residue from the carbon by the injection of steam into the said carbon, and (d) washing the carbon with acid to remove adsorbed inorganic material.
Claim 2
Dependent Claim
173 words
A process for regenerating spent vegetable or mineral activated carbon, comprising (a) subjecting said carbon to an alkaline treatment by contacting said spent carbon in a column with an aqueous alkaline solution having a flow velocity of zero to less than 1 m/hour through said column at a temperature of about 20* to 130*C., for a period of about 30 minutes to 2 hours to change the polarity of the carbon and condition it for solvent displacement of the adsorbed substances on said carbon, (b) eluting said adsorbed organic substances by solubilizing and displacing said adsorbed organic substances on said carbon with an aqueous organic solvent eluting solution, which is passed through said carbon in said column at a higher flow velocity than said alkaline solvent, and wherein said organic solvent is selected from the group consisting of lower alcohols, acetone and dichloroethane, (c) removing said eluting solvent residue from the carbon by the injection of steam into the said carbon, and (d) washing the carbon with acid to remove adsorbed inorganic material.
Claim 3
Dependent Claim
27 words
The process of claim 1 wherein said aqueous alkaline solution is selected from the group consisting of aqueous solutions of potassium hydroxide, sodium hydroxide and ammonium hydroxide.
Claim 4
Dependent Claim
23 words
The process of claim 2 wherein said alkaline liquid is an aqueous solution containing 0.5 to 25 percent by weight of sodium hydroxide.
Claim 5
Dependent Claim
18 words
The process of claim 1 wherein said alkaline treatment temperature is in the range of 25* to 90*C.
Claim 6
Dependent Claim
15 words
The process of claim 1 wherein said alkaline treatment temperature is between 70* and 80*C.
Claim 7
Dependent Claim
22 words
The process of claim 1, wherein the elution solvent is selected from the group consisting of methanol, ethanol, propanol, isopropanol and butanol.
Claim 8
Dependent Claim
23 words
The process of claim 6 wherein the elution solvent is an aqueous solution containing 20 to 75 percent by volume of isopropyl alcohol.
Claim 9
Dependent Claim
31 words
The process of claim 1 wherein said temperature of the treatment with the elution solvent is lower than the boiling temperature of said solvent at the pressure in the reaction zone.
Claim 10
Dependent Claim
31 words
The process of claim 1 wherein said temperature of treatment with the elution solvent is approximately that of the boiling temperature of said solvent at the temperature in the reaction zone.
Claim 11
Dependent Claim
38 words
The process of claim 1 which is carried out continuously and wherein the said alkaline treatment is carried out at a slow flow velocity of said alkaline solution over the carbon, the said velocity not exceeding 1 m/h.
Claim 12
Dependent Claim
25 words
The process of claim 1 wherein the circulation velocity of said elution solvent is faster than 1 m/h and up to and including 10 m/h.
Claim 13
Dependent Claim
66 words
The process of claim 1 wherein a aqueous alkaline hydroalcoholic solution is used for the alkaline treatment step (a) and for the elution step, (b) in which case the circulation of the said solution during the alkaline treatment is carried out under practically stationary flow conditions, whereas the circulation of the said same solution during the elution step is effected at a different velocity above lm/h.
Claim 14
Dependent Claim
30 words
The process of claim 12 wherein the flow velocity of the said aqueous alkaline hydroalkaline solution during the elution step is about 5 times faster than during the alkaline treatment.
Claim 15
Dependent Claim
21 words
The process of claim 1 wherein said activated carbon has a surface area in the range of 500 to 1500 m2/g.
Claim 16
Dependent Claim
24 words
The process of claim 1 wherein, instead of circulating steam over the said activated carbon it is contacted with super heated water under pressure.
Claim 17
Dependent Claim
18 words
The process of claim 1 wherein hot air is injected onto the said activated carbon instead of steam.
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) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |