US4693798A
Expired / Lapsed
US
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Method of treating contaminant ions in an aqueous medium with electrolytically generated ferrous ions, and apparatus therefor
Assignee: NIAGARA ENVIRONMENTAL ASSOCIATES INC A CORP OF NY
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Filing: 1982-09-07
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Granted: 1987-09-15
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Expires: 2002-09-07
Abstract
Abstract An aqueous medium containing contaminant ions such as hexavalent chromium ions is treated by introducing electrolytically generated ferrous ions which are preferably generated in water acidified to a low enough pH to prevent the formation of flocculent material. The ferrous ions reduce the hexavalent chromium ions to a trivalent state, and thereafter alkaline material is introduced into the medium to raise its pH high enough to cause insoluble chromic hydroxide and ferric hydroxide to precipitate. The apparatus includes a ferrous ion generator for recirculating liquid through an electrolytic cell and a receptacle, from which receptacle liquid for end use can be withdrawn and to which makeup water and acid can be added.
Inventors
- 👤 Stephen B. Gale
- 👤 Philip P. O'Donnell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:47
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/70; C02F1/46; C02F1/461; C02F1/463; C02F1/46104; C02F1/46109; C02F2001/46128; C02F2101/00; C02F2101/10; C02F2101/20; C02F2101/22
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
64 words
Method of treating contaminant ions in a contaminated aqueous medium capable of benefitting from ferrous ions, comprising the steps of: (a) electrolytically generating ferrous ions in a separate aqueous medium having a pH of not more than 2.8, and (b) introducing said separate medium containing ferrous ions into said contaminated medium at a less than 1:1 volumetric ratio of separate medium to contaminated medium.
Claim 2
Dependent Claim
64 words
Method of treating contaminant ions in a contaminated aqueous medium capable of benefitting from ferrous ions, comprising the steps of: (a) electrolytically generating ferrous ions in a separate aqueous medium having a pH of not more than 2.8, and (b) introducing said separate medium containing ferrous ions into said contaminated medium at a less than 1:1 volumetric ratio of separate medium to contaminated medium.
Claim 3
Dependent Claim
93 words
Method of providing ferrous ions for treating contaminant ions in a contaminated aqueous medium including hexavalent chromium ions reducible to a trivalent state, comprising the steps of: (a) electrolytically generating ferrous ions in a separate aqueous medium having a pH of not more than 2.8, and (b) introducing said separate medium into said contaminated medium at a less than 1:1 volumetric ratio of separate medium to contaminated medium and in a quantity to provide a weight ratio of ferrous ions at least 3.2 times that of the hexavalent chromium ions to be reduced.
Claim 4
Dependent Claim
93 words
Method of providing ferrous ions for treating contaminant ions in a contaminated aqueous medium including hexavalent chromium ions reducible to a trivalent state, comprising the steps of: (a) electrolytically generating ferrous ions in a separate aqueous medium having a pH of not more than 2.8, and (b) introducing said separate medium into said contaminated medium at a less than 1:1 volumetric ratio of separate medium to contaminated medium and in a quantity to provide a weight ratio of ferrous ions at least 3.2 times that of the hexavalent chromium ions to be reduced.
Claim 5
Dependent Claim
110 words
Method of providing ferrous ions for treating contaminant ions in a contaminated aqueous medium capable of benefitting from ferrous ions, comprising the steps of: (a) electrolytically generating ferrous ions in a separate liquid body of an aqueous medium to raise its ferrous ion content to a predetermined level, (b) bleeding off a portion of said separate body after its ferrous ion content has been raised to said level and introducing it into said contaminated medium at a less than 1:1 volumetric ratio of said portion bled off to said contaminated medium, and (c) introducing additional aqueous medium into said separate body to make up volumetrically for said portion bled off.
Claim 6
Dependent Claim
110 words
Method of providing ferrous ions for treating contaminant ions in a contaminated aqueous medium capable of benefitting from ferrous ions, comprising the steps of: (a) electrolytically generating ferrous ions in a separate liquid body of an aqueous medium to raise its ferrous ion content to a predetermined level, (b) bleeding off a portion of said separate body after its ferrous ion content has been raised to said level and introducing it into said contaminated medium at a less than 1:1 volumetric ratio of said portion bled off to said contaminated medium, and (c) introducing additional aqueous medium into said separate body to make up volumetrically for said portion bled off.
Claim 7
Dependent Claim
113 words
Method of providing ferrous ions for treating contaminant ions in a contaminated stream of an aqueous medium capable of benefitting from ferrous ions, comprising the steps of: (a) recirculating a separate confined liquid body of an aqueous medium through an electrolytic cell having iron electrodes to generate ferrous ions for a length of time to raise the ferrous ion content of said separate body to a predetermined level, and (b) thereafter bleeding off a portion of said separate body and introducing it into said stream at a flow rate less than that of said stream, while introducing additional aqueous medium into said separate body to make up volumetrically foe said portion bled off.
Claim 8
Dependent Claim
113 words
Method of providing ferrous ions for treating contaminant ions in a contaminated stream of an aqueous medium capable of benefitting from ferrous ions, comprising the steps of: (a) recirculating a separate confined liquid body of an aqueous medium through an electrolytic cell having iron electrodes to generate ferrous ions for a length of time to raise the ferrous ion content of said separate body to a predetermined level, and (b) thereafter bleeding off a portion of said separate body and introducing it into said stream at a flow rate less than that of said stream, while introducing additional aqueous medium into said separate body to make up volumetrically foe said portion bled off.
Claim 9
Dependent Claim
150 words
Mthod of electrolytically generating ferrous ions for treating any contaminated water capable of benefiting from ferrous ions, comprising the steps of: (a) providing a confined liquid body of an aqueous medium separate from said contaminated water and having a predetermined upper pH limit, (b) continuously recirculating such separate body through an electrolytic cell having iron electrodes to generate ferrous ions in said separate body, (c) after the ferrous ion content of said separate body has been raised to a predetermined level, continuously bleeding off a portion of said separate body (d) continuously adding aqueous medium to such recirculating liquid body to make up volumetrically for said portion bled off while maintaining the pH of said recirculating body at not more than said limit, and (e) introducing said portion bled off into said contaminated water at a less than 1:1 volumetric ratio of said potion bled off to said contaminated water.
Claim 10
Dependent Claim
150 words
Mthod of electrolytically generating ferrous ions for treating any contaminated water capable of benefiting from ferrous ions, comprising the steps of: (a) providing a confined liquid body of an aqueous medium separate from said contaminated water and having a predetermined upper pH limit, (b) continuously recirculating such separate body through an electrolytic cell having iron electrodes to generate ferrous ions in said separate body, (c) after the ferrous ion content of said separate body has been raised to a predetermined level, continuously bleeding off a portion of said separate body (d) continuously adding aqueous medium to such recirculating liquid body to make up volumetrically for said portion bled off while maintaining the pH of said recirculating body at not more than said limit, and (e) introducing said portion bled off into said contaminated water at a less than 1:1 volumetric ratio of said potion bled off to said contaminated water.
Claim 11
Dependent Claim
19 words
Method as set forth in claim 3, wherein the pH of said separate body is not more than 2.8.
Claim 12
Dependent Claim
62 words
Method as set forth in claim 3 or 6, wherein said contaminant ions include hexavalent chromium ions reducible to a trivalent state, and said portion of said separate body containing ferrous ions is introduced into said contaminated medium in a quantity to provide a weight ratio of ferrous ions at least 3.2 times that of the hexavalent chromium ions to be reduced.
Claim 13
Dependent Claim
19 words
Method as set forth in claim 4, wherein the pH of said separate body is not more than 2.8.
Claim 14
Dependent Claim
61 words
Method as set forth in claim 4 or 8, wherein said contaminant ions include hexavalent chromium ions reducible to a trivalent state, and said portion of said separate body containing ferrous ions is introduced into said stream in a quantity to provide a weight ratio of ferrous ions at least 3.2 times that of the hexavalent chromium ions to be reduced.
Claim 15
Dependent Claim
13 words
Method as set forth in claim 5, wherein said upper pH is 2.8.
Claim 16
Dependent Claim
62 words
Method as set forth in claim 5 or 10, wherein said contaminated water includes hexavalent chromium ions reducible to a trivalent state, and said portion of said separate body containing ferrous ions is introduced into said contaminated water in a qantity to provide a weight ratio of ferrous ions at least 3.2 times that of the hexavlent chromium ions to be reduced.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-09-14 | 1991-03-16 | 1991-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-09-14 | 1995-03-16 | 1995-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-09-14 | 1999-03-16 | 1999-09-15 | $7700.00 | Window Closed / Lapsed |