Methods of using ozone to degrade organic material

• US 20030039729A1
• Filed: 05/14/2002
• Published: 02/27/2003
• Est. Priority Date: 07/13/1993
• Status: Active Grant

• Current Assignee: Lynntech International, Ltd.
• Original Assignee: Lynntech Incorporated
• Inventors: Murphy, Oliver J., Hitchens, G. Duncan
• Granted Patent: US 6,620,210 B2
• Time in Patent Office: Days
• US Class Current: 426/320
• CPC Class Codes: B01D 53/22 by diffusion manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00
• CPC Class Codes: B01D 53/326 in electrochemical cells
• CPC Class Codes: B01F 23/12 with vaporisation of a liquid disinfection, sterilisation or deodorisation of air A61L9/00
• CPC Class Codes: B01J 19/2475 Membrane reactors
• CPC Class Codes: B01J 2208/00061 of the reactants
• CPC Class Codes: B01J 2208/00132 Tubes
• CPC Class Codes: B01J 2208/00256 in a heat exchanger for the heat exchange medium separate from the reactor
• CPC Class Codes: B01J 2208/00539 Pressure
• CPC Class Codes: B01J 2208/00584 Controlling the density
• CPC Class Codes: B01J 2219/00063 of the reactants
• CPC Class Codes: B01J 2219/00081 Tubes
• CPC Class Codes: B01J 2219/00099 the reactor being immersed in the heat exchange medium
• CPC Class Codes: B01J 2219/00103 in a heat exchanger separate from the reactor
• CPC Class Codes: B01J 2219/00162 controlling the pressure
• CPC Class Codes: B01J 2219/00171 controlling the density
• CPC Class Codes: B01J 8/009 Membranes, e.g. feeding or removing reactants or products to or from the catalyst bed through a membrane
• CPC Class Codes: C01B 13/10 Preparation of ozone
• CPC Class Codes: C01B 15/01 Hydrogen peroxide
• CPC Class Codes: C02F 1/32 with ultraviolet light
• CPC Class Codes: C02F 1/46104 Devices therefor; Their operating or servicing
• CPC Class Codes: C02F 1/4672 : by electrooxydation
• CPC Class Codes: C02F 1/78 : with ozone C02F1/4672 takes precedence
• CPC Class Codes: C02F 2001/46128 : Bipolar electrodes
• CPC Class Codes: C02F 2001/46142 : Catalytic coating
• CPC Class Codes: C02F 2001/46166 : Gas diffusion electrodes
• CPC Class Codes: C02F 2101/30 : Organic compounds
• CPC Class Codes: C02F 2201/46115 : Electrolytic cell with membranes or diaphragms
• CPC Class Codes: C02F 2201/782 : Ozone generators
• CPC Class Codes: C02F 2303/04 : Disinfection
• CPC Class Codes: C02F 2305/023 : Reactive oxygen species, singlet oxygen, OH radical
• CPC Class Codes: C11D 2111/12 : Soft surfaces, e.g. textile
• CPC Class Codes: C11D 7/02 : Inorganic compounds
• CPC Class Codes: C25B 1/13 : Ozone
• CPC Class Codes: C25B 1/30 : Peroxides
• CPC Class Codes: H01M 2300/0082 : Organic polymers
• CPC Class Codes: H01M 8/0289 : Means for holding the electrolyte solid polymer electrolytes H01M8/1018
• CPC Class Codes: H01M 8/04291 : Arrangements for managing water in solid electrolyte fuel cell systems H01M8/04119 takes precedence
• CPC Class Codes: H01M 8/1023 : having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• CPC Class Codes: H01M 8/1039 : halogenated, e.g. sulfonated polyvinylidene fluorides
• CPC Class Codes: H01M 8/186 : by electrolytic decomposition of the electrolytic solution or the formed water product
• CPC Class Codes: Y02C 20/30 : of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]
• CPC Class Codes: Y02E 60/50 : Fuel cells

Abstract

Methods of using ozone have been developed which sterilize instruments and medical wastes, oxidize organics found in wastewater, clean laundry, break down contaminants in soil into a form more readily digested by microbes, kill microorganisms present in food products, and destroy toxins present in food products. The preferred methods for killing microorganisms and destroying toxins use pressurized, humidified, and concentrated ozone produced by an electrochemical cell.

Claims

1. A method of sterilizing instruments comprising the steps of:

placing biologically contaminated instruments into an enclosed chamber,

evacuating air from the chamber;

introducing a gas having an ozone concentration greater than about 7 weight percent into the chamber;

contacting the instruments with the gas for a period of time sufficient to allow the ozone to sterilize contaminants on the instruments;

withdrawing the gas from the chamber at a rate sufficient to maintain an average ozone concentration in the chamber that is greater than about 4 weight percent;

removing the gas from the chamber; and

removing the sterilized instruments.

2. The method of claim 1 further comprising the step of:

pressurizing the gas within the chamber to a pressure greater than about 20 psi.

3. The method of claim 1 further comprising the step of:

humidifying the gas in the chamber to be substantially saturated with water.

4. The method of claim 3 wherein the ozone is generated in a humidified form by an electrochemical cell comprising:

an anode disposed in an anodic chamber comprising a substrate and a catalyst coating, wherein the substrate is selected from the group consisting of porous titanium, titanium suboxides, platinum, tungsten, tantalum, hafnium and niobium, and wherein the catalyst coating is selected from the group consisting of lead dioxide, platinum-tungsten alloys or mixtures, glassy carbon and platinum;

a cathode disposed in a cathodic chamber; and

a proton exchange membrane having a first side in contact with the cathode and a second side in contact with the anodic catalyst layer, wherein the proton exchange membrane is comprised of a perfluorinated sulphonic acid polymer.

5. The method of claim 4 wherein the cathode is compatible with liquid phase cathodic depolarizers, wherein the cathode is selected from the group consisting of flow-by electrodes, flow-through electrodes, packed bed electrodes, and fluidized bed electrodes.

6. The method of claim 5 wherein the cathode is a gas diffusion electrode comprising a polytetrafluoroethylene-bonded, semi-hydrophobic catalyst layer supported on a hydrophobic gas diffusion layer, wherein the catalyst layer is comprised of a proton exchange polymer, polytetrafluorethylene polymer and a metal selected from the group consisting of platinum, palladium, gold, iridium, nickel and mixtures thereof, and wherein the gas diffusion layer has a carbon cloth or carbon paper fiber impregnated with a sintered mass derived from fine carbon powder and a polytetrafluoroethylene emulsion.

7. The method of claim 2 wherein the ozone is generated under pressure by an electrochemical cell comprising:

an anode disposed in an anodic chamber comprising a substrate and a catalyst coating, wherein the substrate is selected from the group consisting of porous titanium, titanium suboxides, platinum, tungsten, tantalum, hafnium and niobium, and wherein the catalyst coating is selected from the group consisting of lead dioxide, platinum-tungsten alloys or mixtures, glassy carbon and platinum;

a cathode disposed in a cathodic chamber; and

a proton exchange membrane having a first side in contact with the cathode and a second side in contact with the anodic catalyst layer, wherein the proton exchange membrane is comprised of a perfluorinated sulphonic acid polymer.

8. The method of claim 7 wherein the cathode is compatible with liquid phase cathodic depolarizers, wherein the cathode is selected from the group consisting of flow-by electrodes, flow-through electrodes, packed bed electrodes, and fluidized bed electrodes.

9. The method of claim 8 wherein the cathode is a gas diffusion electrode comprising a polytetrafluoroethylene-bonded, semi-hydrophobic catalyst layer supported on a hydrophobic gas diffusion layer, wherein the catalyst layer is comprised of a proton exchange polymer, polytetrafluorethylene polymer and a metal selected from the group consisting of platinum, palladium, gold, iridium, nickel and mixtures thereof, and wherein the gas diffusion layer has a carbon cloth or carbon paper fiber impregnated with a sintered mass derived from fine carbon powder and a polytetrafluoroethylene emulsion.

10. A method of treating microorganisms present in food products comprising the step of:

contacting the food products with ozone for a period of time sufficient to allow the ozone to kill the microorganisms.

11. The method of claim 10 wherein the food product is selected from the group consisting of meats, seafood, fish, and grains.

12. The method of claim 11 wherein the food product is grain and the microorganism is a fungi that produces mycotoxin.

13. The method of claim 12 wherein the mycotoxin is selected from the group consisting of aflatoxins, fumonosin, cyclopiezoic acid, ochratoxin, patulin, secalonic acid A, and zearalenone.

14. A method of treating microorganisms present in food products comprising the steps of:

contacting the food products with ozone for a period of time sufficient to allow the ozone to destroy toxins on the food products.

15. A method of remediating contaminants in soil comprising the steps of:

preparing a well which passes substantially below an area of contaminated soil;

introducing a gas having an ozone concentration greater than about 7 weight percent through the well and into the contaminated soil;

venting the gas upward through the contaminated soil for a period of time sufficient to allow the ozone to break down the contaminants into a form more readily digested by microbes.

16. The method of claim 15 further comprising the steps of:

replenishing the population of microbes in the soil.

17. A method for electrochemical production of ozone comprising the steps of:

supplying a source of oxygen gas to a gas diffusion cathode, wherein the gas diffusion cathode includes a gas diffusion layer and a catalyst layer, said gas diffusion layer comprising carbon cloth or carbon paper fiber impregnated with a sintered mass derived from fine carbon powder and a polytetrafluoroethylene emulsion, said catalyst layer comprising a proton exchange polymer, polytetrafluorethylene polymer and a metal selected from the group consisting of platinum, palladium, gold, iridium, nickel and mixtures thereof;

supplying water to an anode comprising a substrate and a catalyst coating, wherein the substrate is selected from the group consisting of porous titanium, titanium suboxides, platinum, tungsten, tantalum, hafnium and niobium, and wherein the catalyst coating is selected from the group consisting of lead dioxide, platinum-tungsten alloys or mixtures, glassy carbon and platinum; and

passing an electric current through the anode and the gas diffusion cathode separated by a proton exchange membrane comprising a perfluorinated sulfonic acid polymer material, wherein the proton exchange membrane is bonded to the catalyst layer of the gas diffusion cathode, and wherein ozone is formed at the anode and hydrogen peroxide is formed at the cathode.

18. The method of claim 17 wherein the oxygen is supplied as air.

19. The method of claim 17 further comprising the steps of:

combining the ozone and hydrogen peroxide into a single product;

adding the product into wastewater containing organic substances;

reacting the product with the organic substances;

exposing the product-containing wastewater to ultraviolet radiation;

maintaining a residual of the product in the wastewater stream; and

eliminating the product from the wastewater before use.

20. A method of sterilizing a mixture of medical waste comprising the steps of:

shredding a mixture of medical wastes;

agitating the shredded waste in a chamber;

introducing a gas having an ozone concentration greater than about 7 weight percent into the chamber;

contacting the shredded waste with the gas for a period of time sufficient to allow the ozone to sterilize; and

disposing the sterilized medical waste.

21. The method of claim 20 wherein the ozone is generated in an electrochemical cell.

22. A method of washing laundry without detergent comprising the steps of:

agitating laundry in an enclosed, substantially sealed vessel filled with water;

introducing and bubbling a gas having an ozone concentration greater than about 7 weight percent into the water;

contacting the laundry with the ozonated water for a period of time sufficient to allow the ozone to clean the laundry;

discarding the ozonated water from the vessel;

allowing the residual ozone on the laundry to decompose; and

removing the clean laundry from the vessel.

23. The method of claim 22 wherein the ozone is generated in an electrochemical cell.