Electrochemical process and apparatus to control the chemical state of a material

• US 4,243,751 A
• Filed: 06/01/1978
• Issued: 01/06/1981
• Est. Priority Date: 06/01/1978
• Status: Expired due to Term

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Swartz, Mitchell R.
• Primary Examiner(s): Marcus, Michael S.
• Application Number:
  US05/911,625
• Time in Patent Office: 950 Days
• Field of Search: 47/1.4, 195/103.5 R, 195/127, 195/DIG. 11, 356/40, 356/41, 422/98, 422/186, 422/83, 23/232 E, 23/230 R, 204/1 P, 204/1 S, 204/1 T, 204/1 Y, 204/73, 204/160, 204/195 R, 204/195 T, 204/158, 204/180 B, 204/180 P, 204/195 B, 204/195 S, 435/168, 435/173
• US Class Current: 435/168
• CPC Class Codes: C01B 3/042 Decomposition of water
• CPC Class Codes: C12M 21/02 Photobioreactors culturing algae A01G33/00, A01H4/001, C12N1/12
• CPC Class Codes: C12M 21/04 for producing gas, e.g. biogas digesters for manure with production of biogas A01C3/028, biological treatment of water, waste water or sewage C02F3/00, C02F11/02, preparation of natural gas or syngas C10L3/06, C10L3/10
• CPC Class Codes: C12M 21/18 Apparatus specially designed for the use of free, immobilized or carrier-bound enzymes
• CPC Class Codes: C12M 23/06 Tubular C12M23/08, C12M23/16 take precedence
• CPC Class Codes: C12M 29/04 Filters; Permeable or porous membranes or plates, e.g. dialysis
• CPC Class Codes: C12M 35/02 Electrical or electromagnetic means, e.g. for electroporation or for cell fusion
• CPC Class Codes: C12N 1/12 Unicellular algae; Culture media therefor as new plants A01H13/00
• CPC Class Codes: C12N 13/00 Treatment of microorganisms or enzymes with electrical or wave energy, e.g. magnetism, sonic waves
• CPC Class Codes: C12N 2710/00051 Methods of production or purification of viral material
• CPC Class Codes: C12N 7/00 Viruses; Bacteriophages; Compositions thereof; Preparation or purification thereof preparing medicinal viral antigen or antibody compositions, e.g. virus vaccines, A61K39/00
• CPC Class Codes: C12P 1/00 Preparation of compounds or compositions, not provided for in groups C12P3/00 - C12P39/00, by using microorganisms or enzymes
• CPC Class Codes: C12P 3/00 Preparation of elements or inorganic compounds except carbon dioxide recovery of carbon dioxides as by-products C12F3/02
• CPC Class Codes: G01N 33/007 Arrangements to check the analyser calibrating G01N33/0006
• CPC Class Codes: H01L 31/0224 Electrodes
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y10T 436/2525 Stabilizing or preserving

Abstract

Electrochemical process and apparatus to control the chemical state of a material, that is, to cause said material to retain desired characteristics in an environment that normally would cause a change in those characteristics or to cause a material that has deteriorated from a desired chemical state to revert to the desired state.

Claims

1. In a process wherein a chemical change is wrought upon a material as a consequence of it having been subjected to a reaction or reactions, which chemical change is an unwanted chemical deterioration resulting from a reversible reaction which can be counteracted by introducing appropriate charge carriers, electrons or holes, into the electronic states of said material, the further steps of adding small amounts of an electroactive mediator to the material to facilitate the charge carrier transfer to said electronic states, the resulting material being a matrix material and the electroactive mediator, said matrix material containing an inorganic catalyst used to effect the chemical reaction in which changes in character in the course of the chemical reaction are due to the environment within which the process occurred, introducing photons to the resulting material, the electroactive mediator being one which permits, in the presence of said photons, charge carrier transfer to the resulting material at an applied electric potential difference that is below the electrolysis potential of the resulting material, and applying an electric potential across the resulting material to inject appropriate charge carriers into the resulting material and into the electronic states thereof to counteract the unwanted chemical deterioration and cause the material to revert to a desired state.

2. A process as claimed in claim 1 wherein said electroactive mediator is taken from the group consisting essentially of dyes, quinones, free transition metals and other molecules with conjugated π

-electron systems as well as other elements and complexes with d^- and f^- electrons capable of moving between two or more electronic states.

3. A process as claimed in claim 1 wherein the electroactive mediator is one which permits the charge transfer in the presence of photons of a narrow range of frequencies and in which the photons introduced are within that range.

4. A process as claimed in claim 1 wherein said deterioration is oxidation and wherein the reversion to a desired state is effected by reduction of the matrix material by introducing holes to said electronic states.

5. A process as claimed in claim 1 wherein said reversible deterioration is reduction and wherein the reversion to a desired state is effected by oxidation of the matrix material by introducing electrons to said electronic states.

6. A process as claimed in claim 1 wherein the electric potential is maintained for a time τ

_R, wherein ##EQU2## wherein Σ

is the molar sum of all oxidized constituents in said resulting material and k is electric current in microamperes.

7. A process as claimed in claim 6 wherein τ

_R <

τ

_o, τ

_o being the characteristic time of oxidation.

8. A system that comprises, in combination:

material means that is subjected to a reaction or an environment which effects or tends to effect deterioration thereof by virtue of chemical processes, which deterioration is caused by a reversible reaction which can be counteracted by introducing appropriate charge carriers into the electronic states of said material means, said material means containing small amounts of an electroactive mediator to facilitate introduction of the charge carriers into the electronic states of said material means, said material means containing an enzyme used to effect the chemical reaction or reactions;

means to contain the enzyme;

means permitting a substrate to come in contact with the enzyme to produce a product;

porous means permeable to the substrate and to the product to enable the product to be removed from the region of the enzyme;

means to subject the material means to an electric field of sufficiently high intensity to counteract said deterioration and cause the material means to assume or to retain a desired state by the introduction of said charge carriers to said electronic states and yet sufficiently low in intensity and sufficiently high in efficiency that no substantial electrolysis occurs; and

means to direct electromagnetic radiation upon the material means to enhance the effect of the electric field in introducing the charge carriers to the electronic states.

9. A system as claimed in claim 8 that further includes anion exchange membrane means that serves to affect the electric field profile, thereby permitting bulk change of said material.

10. A system as claimed in claim 8 wherein said material is a composite material that contains small amounts of said electroactive mediator which permits and enhances charge transfer to said material means in the presence of the electric field and the presence of phonons within a range of frequencies and which the last-named means is adapted to direct phonons in said range into said material means.

11. A system as claimed in claim 8 wherein said material means contains transition metal composites which bind other molecules.

12. A system as claimed in claim 8 wherein said means to subject comprises electrode means and electrical power source means connected to energize the electrode means.

13. A system as claimed in claim 12 in which the means to direct electromagnetic radiation upon the material is adapted to irradiate the electrode means as well.

14. A system as claimed in claim 8 that comprises an outer tube and an inner tube nested and coaxially disposed within the outer tube, with a space therebetween, the enzyme being disposed in said space, the inner tube being operable to receive a substrate and being permeable to the substrate, the substrate thus passing through the inner tube to the enzyme in said space to produce a product, the inner tube being porous also to the product which diffuses back into the inner tube, said electric field being a radial field in the space between the two tubes.

15. A system as claimed in claim 14 that further includes a tubular ion exchange membrane disposed in the space between the inner tube and the outer tube.

16. A system as claimed in claim 14 having means to create a longitudinal electric field along the inner tube to facilitate entry of the substrate into the system and or to facilitate extraction of the product.

17. A system as claimed in claim 16 having means to introduce the enzyme into said space.

18. A system as claimed in claim 17 wherein the means to subject the material means to an electric field is a source of electric potential, that further includes means to sense the electric potential that appears across said space and that further includes feedback connections so that when the regeneration is complete the electric potential is terminated.

19. A method of controlling the aging process of a toxin subject to aging, which aging results from a reversible reaction that can be counteracted by introducing appropriate charge carriers into the electronic states of said toxin, that comprises:

introducing methylene blue as an electroactive mediator to the toxin to facilitate the introduction of charge carriers to the electronic states thereof;

irradiating the toxin further to facilitate the introduction of charge carriers to the electronic states thereof; and

applying an electric potential across the toxin to introduce the charge carriers to the material and into the electronic states thereof, and wherein photons in the red region of the electromatic spectrum are introduced to the toxin to enhance said charge carrier transfer to said toxin.

20. A method as claimed in claim 19 wherein the aging process is accelerated by changing said charge carrier.

21. A process for producing H₂ gas from H₂ O that includes introducing H₂ O to an algae system in the presence of light, which algae system, in the presence of light, separates molecules of H₂ O into O₂ molecules, protons (H⁺) and electrons (e^-), drawing the protons (H⁺) into a material that is operable to add electrons (e^-) to the protons (H⁺) to produce H₂ gas, which material is subject to chemical deterioration that can be counteracted by introducing appropriate charge carriers into the electronic states of said material, the further steps of adding an electroactive mediator to the material, the electroactive mediator being one which, in the presence of photons, permits charge carrier transfer to said electronic states at an applied potential that is below the electrolysis potential of the resulting material, introducing photons to the resulting material, and applying an electric potential across the material to introduce charge carriers thereto.

22. A process for producing H₂ gas from H₂ O that includes the steps of introducing H₂ O to an organic system in the presence of light, which organic system, in the presence of light, separates molecules of H₂ O into O₂ molecules, protons (H⁺) and electrons (e^-), drawing the protons (H⁺) into a material that contains hydrogenase and an electroactive mediator, which material is operable to convert the protons (H⁺) to H₂ gas, said material being subject to reversible deterioration over time, and periodically applying an electric potential across the material to introduce charge carriers into the material, which charge carriers serve to counteract the reversible deterioration and reset the material.

23. In a system for producing H₂ gas from H₂ O, an organic solar cell comprising an organic material that in the presence of solar radiation separates molecules of H₂ O into O₂ molecules, protons (H⁺) and electrons (e^-), cationic exchange membrane means that can pass the protons (H⁺) therethrough, a further material that contains hydrogenase and an electroactive mediator positioned to receive the protons (H⁺) after passage through the cationic exchange membrane means and operable to add an electron (e^-) thereto to produce the H₂ gas therefrom, said further material being subject to deterioration over time, and electronic power source means connected to inject charge carriers into the further material, which charge carriers serve, in the presence of light, to counteract said deterioration and reset the further material.

24. An organic solar cell as claimed in claim 23 wherein the cation exchange membrane means comprises a cation exchange membrane that is thin enough to pass the protons (H⁺) therethrough without an external field applied thereacross.

25. An organic cell as claimed in claim 23 that includes voltage source means positioned to apply an electric potential across the organic material and the cationic exchange membrane means with appropriate polarity to cause the protons (H⁺) to drift toward the cationic exchange membrane means and to diffuse through the cationic exchange membrane means into said further material.

26. An organic solar cell as claimed in claim 23 wherein the organic material contains algae.

27. An organic solar cell as claimed in claim 26, wherein the organic material contains extracts of algae.

28. An organic solar cell as claimed in claim 26 wherein the organic material contains chlorophyll.

29. An organic solar cell as defined by claim 23 wherein the H₂ gas is formed in the bulk of the further material and wherein the power source means comprises spaced electrodes positioned to inject said charge carriers into the bulk of the further material, there being an ion exchange membrane interposed between one of the electrodes and said further material.

30. An organic solar cell as defined by claim 29 wherein said charge carriers are electrons (e^-) directed into the bulk of the further material.