Patent US2653618A successfully refreshed from Google Patents.
US5118422A
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Photocatalytic treatment of water
Assignee: Photo Catalytics Inc
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Filing: 1990-07-24
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Granted: 1992-06-02
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Expires: 2010-07-24
Abstract
Abstract An ultraviolet driven photocatalytic post-treatment technique for the purification of waste water distillates, reverse osmosis permeates and spacecraft habitat atmospheric humidity condensates is described. Experimental results show that organic impurity carbon content of simulated reclamation waters at nominal 40 PPM level are reduced to, PPB using a recirculating batch reactor. The organic impurities common to reclaimed waste waters are completely oxidized employing minimum expendables (stoichiometric oxygen). This paper discusses test results and parameteric data obtained for design and fabrication of a bread-board system. The parametric testing includes UV light source evaluation, photolysis vs photocatalysis comparison, oxygen concentration dependence, temperature dependence, reactor mixing, disinfection features, photocatalyst loading, photocatalyst degradation studies and power consumption estimates. This novel post-treatment approach for waste water reclamation shows potential for integration with closed-loop life support systems.
Inventors
- 👤 Gerald Cooper
- 👤 Matthew A. Ratcliff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:34
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/30; C02F1/32; C02F1/325; C02F9/00; C02F9/20; C02F1/72; C02F1/725; C02F2305/00; C02F2305/10
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
97 words
A process for purifying a water feedstock containing an oxidizable contaminant compound, comprising the steps of mixing the water feedstock with a photocatalytic semiconductor having a particle size in the range of about 0.01 to about 1.0 micron and in an amount of between about 0.01% and about 0.2% by weight of the water, exposing said water and semiconductor mixture to band-gap photons for a time sufficient to effect an oxidation of the oxidizable contaminant compound thereby to purify said water, separating said purified water from said semiconductor by crossflow membrane filtration, and recovering said purified water.
Claim 2
Dependent Claim
97 words
A process for purifying a water feedstock containing an oxidizable contaminant compound, comprising the steps of mixing the water feedstock with a photocatalytic semiconductor having a particle size in the range of about 0.01 to about 1.0 micron and in an amount of between about 0.01% and about 0.2% by weight of the water, exposing said water and semiconductor mixture to band-gap photons for a time sufficient to effect an oxidation of the oxidizable contaminant compound thereby to purify said water, separating said purified water from said semiconductor by crossflow membrane filtration, and recovering said purified water.
Claim 3
Dependent Claim
29 words
A process as defined in claim 1 including the step of determining the kinetics of the photocatalystic reaction and thereafter calculating the time sufficient to effect the oxidation reaction.
Claim 4
Dependent Claim
18 words
A process as defined in claim 1 including the step of intermittent back flushing during said cross-flow filtration.
Claim 5
Dependent Claim
43 words
A process as defined in claim 1 wherein said semiconductor is selected from the group consisting of TiO 2 , ZnO, CdS, CdSe, SnO 2 , SrTiO 3 , WO 3 , Fe 2 O 3 , and Ta 2 O 5 .
Claim 6
Dependent Claim
15 words
A process as defined in claim 4 wherein said semiconductor is anatase TiO 2 .
Claim 7
Dependent Claim
16 words
A process as defined in claim 1 wherein said band-gap photons are contained in ultraviolet light.
Claim 8
Dependent Claim
24 words
A process as defined in claim 1 wherein the flow of said water and semiconductor mixture is at a Reynolds number of about 2000.
Claim 9
Dependent Claim
25 words
A process as defined in claim 6 including the step of adding oxygen gas to the water and semiconductor mixture during exposure to ultraviolet light.
Claim 10
Dependent Claim
21 words
A process as defined in claim 1 wherein said semiconductor is recycled in the process after separation from the purified water.
Claim 11
Dependent Claim
174 words
A process for removing oxidizable contaminants from a water feedstock containing an oxidizable contaminant compound, comprising the steps of mixing the water feedstock with a photocatalytic semiconductor selected from the group consisting of TiO 2 , ZnO, CdS, CdSe, SnO 2 , SrTiO 3 , WO 3 , Fe 2 O 3 , and Ta 2 O 5 , having a particle size in the range of about 0.01 to about 1.0 micron, and in an amount between about 0.01% and about 0.2% by weight of the water; flowing said water and semiconductor mixture through a reactor at a Reynolds number of about 2000 while simultaneously adding oxygen gas to the water and semiconductor mixture and exposing said water and semiconductor mixture to ultraviolet light for a time sufficient to effect oxidation of the oxidizable contaminant compound thereby to purify said water; separating said purified water from said semiconductor in a crossflow membrane filter with intermittent back flushing during said cross-flow filtration; recovering said purified water; and recycling said semiconductor to the water feedstock.
Claim 12
Dependent Claim
174 words
A process for removing oxidizable contaminants from a water feedstock containing an oxidizable contaminant compound, comprising the steps of mixing the water feedstock with a photocatalytic semiconductor selected from the group consisting of TiO 2 , ZnO, CdS, CdSe, SnO 2 , SrTiO 3 , WO 3 , Fe 2 O 3 , and Ta 2 O 5 , having a particle size in the range of about 0.01 to about 1.0 micron, and in an amount between about 0.01% and about 0.2% by weight of the water; flowing said water and semiconductor mixture through a reactor at a Reynolds number of about 2000 while simultaneously adding oxygen gas to the water and semiconductor mixture and exposing said water and semiconductor mixture to ultraviolet light for a time sufficient to effect oxidation of the oxidizable contaminant compound thereby to purify said water; separating said purified water from said semiconductor in a crossflow membrane filter with intermittent back flushing during said cross-flow filtration; recovering said purified water; and recycling said semiconductor to the water feedstock.
Claim 13
Dependent Claim
29 words
A process as defined in claim 10 including the step of determining the kinetics of the photocatalytic reaction and thereafter calculating the time sufficient to effect the oxidation reaction.
Claim 14
Dependent Claim
15 words
A process as defined in claim 10 wherein said semiconductor is anatase TiO 2 .
Claim 15
Dependent Claim
14 words
A process as defined in claim 10 wherein said ultraviolet light supplies band-gap photons.
Claim 16
Dependent Claim
160 words
A process for removing oxidizable contaminants from a water feedstock containing an oxidizable contaminant compound, comprising the steps of mixing the water feedstock with a photocatalytic semiconductor selected from the group consisting of TiO 2 , ZnO, CdS, CdSe, SnO 2 , SrTiO 3 , WO 3 , Fe 2 O 3 , and Ta 2 O 5 , having a particle size in the range of about 0.01 to about 1.0 micron, and in an amount of between about 0.01% and about 0.2% by weight of the water; flowing said water and semiconductor mixture through a reactor at a Reynolds number of about 2000 while simultaneously adding oxygen gas to the water and semiconductor mixture and exposing said water and semiconductor mixture to ultraviolet light for a time sufficient to effect oxidation of the oxidizable contaminant compound thereby to purify said water; separating said purified water from said semiconductor in a crossflow membrane filter; and recovering said purified water.
Claim 17
Dependent Claim
160 words
A process for removing oxidizable contaminants from a water feedstock containing an oxidizable contaminant compound, comprising the steps of mixing the water feedstock with a photocatalytic semiconductor selected from the group consisting of TiO 2 , ZnO, CdS, CdSe, SnO 2 , SrTiO 3 , WO 3 , Fe 2 O 3 , and Ta 2 O 5 , having a particle size in the range of about 0.01 to about 1.0 micron, and in an amount of between about 0.01% and about 0.2% by weight of the water; flowing said water and semiconductor mixture through a reactor at a Reynolds number of about 2000 while simultaneously adding oxygen gas to the water and semiconductor mixture and exposing said water and semiconductor mixture to ultraviolet light for a time sufficient to effect oxidation of the oxidizable contaminant compound thereby to purify said water; separating said purified water from said semiconductor in a crossflow membrane filter; and recovering said purified water.
Claim 18
Dependent Claim
29 words
A process as defined in claim 14 including the step of determining the kinetics of the photocatalytic reaction and thereafter calculating the time sufficient to effect the oxidation reaction.
Claim 19
Dependent Claim
18 words
A process as defined in claim 14 including the step of intermittent back flushing during said cross-flow filtration.
Claim 20
Dependent Claim
15 words
A process as defined in claim 14 where said semiconductor is anatase TiO 2 .
Claim 21
Dependent Claim
14 words
A process as defined in claim 14 wherein said ultraviolet light supplies band-gap photons.
Claim 22
Dependent Claim
21 words
A process as defined in claim 14 wherein said semiconductor is recycled in the process after separation from the purified water.
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) | 1995-06-02 | 1995-12-02 | 1996-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-02 | 1999-12-02 | 2000-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-02 | 2003-12-02 | 2004-06-02 | $7700.00 | Window Closed / Lapsed |