CN217052423U

CN217052423U - Microbial electrosynthesis reactor

Info

Publication number: CN217052423U
Application number: CN202123305214.4U
Authority: CN
Inventors: 林琳; 杜瑾; 李晓岩; 李炳; 周恩财; 赵明
Original assignee: Shenzhen International Graduate School of Tsinghua University
Current assignee: Shenzhen International Graduate School of Tsinghua University
Priority date: 2021-12-24
Filing date: 2021-12-24
Publication date: 2022-07-26
Anticipated expiration: 2031-12-24

Abstract

The utility model discloses a microbial electrosynthesis reactor, which comprises a reaction component, a first circulation component and a second circulation component. Reaction unit includes the shell, the negative pole, proton exchange membrane and positive pole, the shell is equipped with the holding chamber, first inlet opening, first apopore, second inlet opening and second apopore, proton exchange membrane and negative pole all are the tubulose, the negative pole, the holding chamber is all arranged in to proton exchange membrane and positive pole, and the negative pole, proton exchange membrane and positive pole are followed and are inwards overlapped in proper order and establish, proton exchange membrane separates the holding chamber for cathode chamber and anode chamber, first inlet opening and first apopore all communicate with the cathode chamber, second inlet opening and second apopore all communicate with the anode chamber. The utility model discloses a little biological electricity synthesis reactor can effectively improve the effective area of negative pole and the volume ratio of reactor, simultaneously, and the distance between negative pole and the positive pole is dwindled by a wide margin to can reduce the ohmic loss that the ion migration arouses in electrolyte, in addition, improve proton exchange membrane's effective area.

Description

Microbial electrosynthesis reactor

Technical Field

The utility model relates to a little bioelectrochemistry technical field especially relates to a little biological electricity synthesis reactor.

Background

In recent years, carbon emission reduction and energy storage can be realized simultaneously by using an electric energy-driven carbon dioxide reduction technology. Compared with the non-biological electrosynthesis technology, the microbial electrosynthesis technology has the advantages of various synthetic products, mild reaction conditions, small environmental pollution and the like. The microorganisms can convert carbon dioxide into organic matters with 1-6 carbon atoms, such as methane, formic acid, acetic acid, ethanol, butyric acid, caproic acid and corresponding alcohols. After separation, purification and secondary processing, the substances can be used as chemicals and fuels for the industries such as chemical industry, energy, transportation and the like, and can bring remarkable economic benefits.

Microbial electrosynthesis takes electric energy as energy input and carbon dioxide as a unique carbon source, and converts renewable electric energy into stable and storable chemical energy. The technology is realized based on the existence of a class of microorganisms capable of directly taking electrons from the electrodes and has the physiological metabolic potential of autotrophic fixation of carbon dioxide. Under mixed conditions, the acetic acid converted from carbon dioxide can be further converted into longer-chain butyric acid and caproic acid by some microorganisms with carbon chain growth capacity. Compared with acetic acid, the medium-long chain volatile fatty acid has higher economic value, thereby bringing wider application prospect for the microbial electrosynthesis technology.

However, the cell yield of autotrophic microorganisms for cathodic carbon dioxide fixation of microbial electrosynthesis systems is much lower than that of heterotrophic microorganisms, resulting in very weak cathodic biofilms. The current density and the production rate of organic products such as acetic acid of the existing microbial electrosynthesis reactor are far from meeting the requirements of industrialization.

In the research reports on microbial electrosynthesis in the last decade, a double-chamber H-type reactor is the most widely used reactor configuration. The double-chamber H-shaped reactor comprises two glass bottles with the same size and structure, wherein the two glass bottles are respectively used as a cathode chamber and an anode chamber. Both glass bottles are provided with through holes so as to facilitate the carbon dioxide gas to enter the cathode chamber and facilitate the oxygen generated in the anode chamber to escape. The cathode chamber and the anode chamber are connected by a bridge, and the two chambers are separated by a cation exchange membrane. The cation exchange membrane can prevent H in the solution in the cathode chamber and the anode chamber from being removed ⁺ Exchange of substances other than the cations, and most importantly, blocking oxygen generated in the anode chamber from entering the cathode chamber so as to avoid affecting the growth of anaerobic microorganisms.

However, in the conventional H-type reactor, the distance between the cathode and the anode is large, and ohmic loss caused by migration of ions in the electrolyte is large, which is not favorable for improving the yield of volatile fatty acid such as acetic acid.

SUMMERY OF THE UTILITY MODEL

The utility model discloses it is big to aim at solving the negative pole that exists among the prior art at least and positive pole interval, and the great problem of ohmic loss that the ion migration arouses in electrolyte. Therefore, the utility model provides a little biological electricity synthesis reactor can effectively shorten the interval of negative pole and positive pole, reduces the ohmic loss that the ion migration arouses in electrolyte.

According to the utility model discloses a little biological electricity synthesis reactor of embodiment includes:

the reaction assembly comprises a shell, a cathode, a proton exchange membrane and an anode, wherein the shell is provided with an accommodating cavity, a first water inlet hole, a first water outlet hole, a second water inlet hole and a second water outlet hole, the proton exchange membrane and the cathode are both in a tubular shape, the cathode, the proton exchange membrane and the anode are all arranged in the accommodating cavity, the cathode, the proton exchange membrane and the anode are sequentially sleeved from outside to inside, the accommodating cavity is divided into a cathode chamber and an anode chamber by the proton exchange membrane, the first water inlet hole and the first water outlet hole are both communicated with the cathode chamber, and the second water inlet hole and the second water outlet hole are both communicated with the anode chamber;

the first circulation assembly comprises a first circulation pipeline, a first circulation pump and a first liquid storage bottle, the first circulation pipeline is provided with a first circulation channel, two ends of the first circulation channel are respectively communicated with the first water inlet and the first water outlet, the first liquid storage bottle is provided with a first liquid storage cavity, the first liquid storage cavity is used for storing cathode solution, the first liquid storage cavity is communicated in the first circulation channel, and the first circulation pump is used for driving the cathode solution to circularly flow between the first liquid storage cavity and the cathode chamber;

the second circulation assembly comprises a second circulation pipeline, a second circulation pump and a second liquid storage bottle, the second circulation pipeline is provided with a second circulation channel, two ends of the second circulation channel are respectively communicated with the second water inlet hole and the second water outlet hole, the second liquid storage bottle is provided with a second liquid storage cavity, the second liquid storage cavity is used for storing anode solution, the second liquid storage cavity is communicated with the second circulation channel, and the second circulation pump is used for driving the anode solution to be in the second liquid storage cavity and the anode chamber to circulate and flow.

According to the utility model discloses little biological electricity synthesis reactor has following beneficial effect at least: the cathode, the proton exchange membrane and the anode are all arranged in the accommodating cavity, so that the distance between the cathode and the anode is favorably shortened, and the ohmic loss caused by the migration of ions in the electrolyte is reduced; in addition, the cathode solution is circulated outside the accommodating cavity through the first circulating assembly, so that the volume of the cathode chamber is reduced, the anode solution is circulated outside the accommodating cavity through the second circulating assembly, the volume of the anode chamber is reduced, the distance between the cathode and the anode is shortened, and the ohmic loss caused by the migration of ions in the electrolyte is reduced.

According to some embodiments of the invention, the cathode is attached to an inner surface of the receiving cavity.

According to some embodiments of the invention, the housing chamber is cylindrical, and the proton exchange membrane and the cathode are both in the shape of a circular tube.

According to some embodiments of the utility model, the axle center of first inlet opening with the contained angle in the axle center in holding chamber is the acute angle, the axle center of second inlet opening with the contained angle in the axle center in holding chamber is the acute angle.

According to some embodiments of the utility model, first circulation subassembly still includes first pH probe, first stock solution bottle still be equipped with three with the first interface of first stock solution chamber intercommunication, one it is equipped with to insert in the first interface the first pH probe, first pH probe is used for monitoring the pH value of solution in the first stock solution chamber, another first interface is used for letting in gaseous phase substrate, the last one first interface is used for acquireing in the first stock solution chamber solution.

According to some embodiments of the utility model, the second stock solution bottle still be equipped with two with the second interface of second stock solution chamber intercommunication, one the second interface is arranged in discharging the gas that produces among the electrolysis process, another the second interface is used for acquireing in the second stock solution chamber solution.

According to some embodiments of the present invention, the reaction assembly further comprises a support tube, the support tube is located in the accommodating chamber, the support tube is provided with a plurality of through holes penetrating through the inner surface and the outer surface, and the proton exchange membrane is fixed to the support tube at the inner surface or the outer surface.

According to some embodiments of the invention, the material of the support tube is PVC.

According to some embodiments of the invention, the anode comprises one of a graphite rod, a titanium wire and a platinum wire.

According to some embodiments of the invention, the cathode comprises one of carbon paper, carbon cloth, carbon felt, copper foam, nickel foam, carbon paper with surface modification, carbon cloth with surface modification, carbon felt with surface modification, copper foam with surface modification and nickel foam with surface modification.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The invention is further described with reference to the following figures and examples, in which:

FIG. 1 is a schematic diagram of a microbial electrosynthesis reactor in accordance with an embodiment of the present invention;

FIG. 2 is a schematic view of another angle of the reaction assembly of FIG. 1;

FIG. 3 is a schematic structural view of the reaction module of FIG. 1;

fig. 4 is a partial enlarged view of the region i in fig. 3.

Reference numerals: a first circulation component 100, a first circulation pipeline 110, a first circulation pump 120, a first liquid storage bottle 130, a first interface 131, a first liquid storage cavity 132 and a first pH probe 140;

the device comprises a reaction assembly 200, a shell 210, a first water inlet 211, a containing cavity 212, a cathode chamber 213, an anode chamber 214, a second water outlet 215, a first water outlet 216, a second water inlet 217, a cathode 220, a proton exchange membrane 230, an anode 240, a reference electrode 250, a support tube 260 and a through hole 261;

a second circulation component 300, a second circulation pipeline 310, a second circulation pump 320, a second liquid storage bottle 330, a second interface 331 and a second liquid storage cavity 332.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the directional descriptions, such as the directions or positional relationships indicated by upper, lower, front, rear, left, right, etc., are based on the directions or positional relationships shown in the drawings, and are only for convenience of description and simplification of the description, but not for indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present invention.

In the description of the present invention, a plurality of means is one or more, a plurality of means is two or more, and the terms greater than, less than, more than, etc. are understood as excluding the term, and the terms greater than, less than, etc. are understood as including the term. If there is a description of first and second for the purpose of distinguishing technical features only, this is not to be understood as indicating or implying a relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of technical features indicated.

In the description of the present invention, unless there is an explicit limitation, the words such as setting, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in combination with the specific contents of the technical solution.

In the description of the present invention, reference to the description of the terms "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Referring to fig. 1 to 4, a microbial electrosynthesis reactor, in accordance with an embodiment of the present invention, includes a first circulation assembly 100, a reaction assembly 200, and a second circulation assembly 300. The reaction assembly 200 includes a housing 210, a cathode 220, a proton exchange membrane 230, and an anode 240, wherein the housing 210 is provided with a receiving cavity 212, a first water inlet 211, a first water outlet 216, a second water inlet 217, and a second water outlet 215. The proton exchange membrane 230 and the cathode 220 are both tubular, the cathode 220, the proton exchange membrane 230 and the anode 240 are all disposed in the accommodating cavity 212, and the cathode 220, the proton exchange membrane 230 and the anode 240 are sequentially sleeved from outside to inside. The proton exchange membrane 230 divides the accommodating chamber 212 into a cathode chamber 213 and an anode chamber 214, the first inlet 211 and the first outlet 216 are both communicated with the cathode chamber 213, and the second inlet 217 and the second outlet 215 are both communicated with the anode chamber 214.

The first circulation assembly 100 includes a first circulation line 110, a first circulation pump 120, and a first reservoir 130. The first circulation pipeline 110 is provided with a first circulation channel, and two ends of the first circulation channel are respectively communicated with the first water inlet hole 211 and the first water outlet hole 216. The first reservoir 130 is provided with a first reservoir 132, the first reservoir 132 is used for storing cathode solution, and the first reservoir 132 is communicated with the first circulation channel. The first circulation pump 120 is used to circulate the cathode solution between the first reservoir 132 and the cathode chamber 213.

The second circulation assembly 300 includes a second circulation line 310, a second circulation pump 320, and a second reservoir 330. The second circulation pipeline 310 is provided with a second circulation channel, and two ends of the second circulation channel are respectively communicated with the second water inlet 217 and the second water outlet 215. The second liquid storage bottle 330 is provided with a second liquid storage cavity 332, the second liquid storage cavity 332 is used for storing the anode solution, and the second liquid storage cavity 332 is communicated with the second circulation channel. The second circulation pump 320 is used for driving the anode solution to circulate between the second reservoir 332 and the anode chamber 214.

According to the utility model discloses little biological electricity synthesis reactor has following beneficial effect at least: the cathode 220, the proton exchange membrane 230 and the anode 240 are all arranged in the accommodating cavity 212, so that the distance between the cathode 220 and the anode 240 is favorably shortened, and the ohmic loss caused by the migration of ions in the electrolyte is reduced; in addition, the cathode solution is circulated outside the accommodating cavity 212 through the first circulation assembly 100, which is beneficial to reducing the volume of the cathode chamber 213, and the anode solution is circulated outside the accommodating cavity 212 through the second circulation assembly 300, which is beneficial to reducing the volume of the anode chamber 214, and thus is also beneficial to shortening the distance between the cathode 220 and the anode 240, so that ohmic loss caused by migration of ions in the electrolyte is reduced.

In addition, the cathode 220, the proton exchange membrane 230 and the anode 240 are all disposed in the accommodating cavity 212, and the cathode 220, the proton exchange membrane 230 and the anode 240 are sequentially sleeved from outside to inside, that is, the tubular cathode 220 is located outside the proton exchange membrane 230, so that the effective area of the tubular cathode 220 can be increased as much as possible, even approaching the area of the inner surface of the accommodating cavity 212, thereby effectively increasing the ratio of the effective area of the cathode 220 to the volume of the reactor.

In addition, the first reservoir 130 may store a cathode solution containing a microorganism culture medium solution, and the first circulation pump 120 may circulate the cathode solution between the first reservoir 132 and the cathode chamber 213, thereby supplementing the microorganism with the microorganism culture medium solution and achieving hydraulic agitation. The second reservoir 330 may store an anode solution including a mineral salt solution having a certain conductivity, such as a phosphate buffer solution, or a culture medium solution similar to the cathode chamber, and the second circulation pump 320 may be used to circulate the anode solution between the second reservoir 332 and the anode chamber 214, thereby allowing the anode solution in the second reservoir 332 to be fully utilized.

In addition, the microbial electrosynthesis reactor also includes a reference electrode 250. Specifically, peristaltic pumps may be selected for both the first circulation pump 120 and the second circulation pump 320.

Referring to fig. 3, in some embodiments of the present invention, the cathode 220 is attached to the inner surface of the receiving cavity 212. In this case, the surface area of cathode 220 is maximized, and a large number of electrons can be supplied to the surface of microorganisms to attach and take up electrons, which is advantageous for increasing the yield of volatile fatty acids such as acetic acid.

Referring to fig. 1 and 2, in some embodiments of the present invention, the housing 212 is cylindrical, and the pem 230 and the cathode 220 are both tubular. At this time, the accommodating cavity 212, the proton exchange membrane 230 and the cathode 220 are all regular in shape, so that the processing and installation are convenient, and the production cost of the microbial electrosynthesis reactor is favorably reduced.

Specifically, the axis of the accommodating cavity 212, the axis of the proton exchange membrane 230 and the axis of the cathode 220 coincide. Besides the cylindrical shape, the housing 212 may have a polygonal column shape, and the proton exchange membrane 230 and the cathode 220 may have polygonal shapes, which are regular shapes.

Referring to fig. 1 and 2, in a further modification of the above embodiment, an included angle between the axis of the first water inlet hole 211 and the axis of the accommodating cavity 212 is an acute angle, and an included angle between the axis of the second water inlet hole 217 and the axis of the accommodating cavity 212 is an acute angle.

At this time, the first water inlet hole 211 does not face the proton exchange membrane 230 (or the cathode 220), and the solution introduced into the cathode chamber 213 from the first water inlet hole 211 is introduced obliquely, so that the solution stored in the cathode chamber 213 can be agitated, and the solution in the cathode chamber 213 can be more uniform. Similarly, the second water inlet 217 does not face the pem 230 (or the cathode 220), and the solution entering the anode chamber 214 from the second water inlet 217 is inclined so as to stir the solution stored in the anode chamber 214 and make the solution in the anode chamber 214 more uniform.

Specifically, the included angle between the axis of the first water inlet hole 211 and the axis of the accommodating cavity 212 may be 30 °, 45 °, 120 ° or other angles, and the included angle between the axis of the second water inlet hole 217 and the axis of the accommodating cavity 212 may be 30 °, 45 °, 120 ° or other angles.

Referring to fig. 1, in some embodiments of the present invention, first circulation assembly 100 further comprises a first pH probe 140, first reservoir 130 is further provided with three first ports 131 communicated with first reservoir 132, a first pH probe 140 is inserted into one first port 131, first pH probe 140 is used for monitoring pH of the solution in first reservoir 132, another first port 131 is used for introducing a gas phase substrate (e.g., carbon dioxide, hydrogen, etc.), and the last first port 131 is used for obtaining the solution in first reservoir 132.

Therefore, through the three first interfaces 131, the pH value of the solution in the first reservoir 132 can be monitored in real time, the gas phase substrate can be supplemented in time, the sample of the solution in the first reservoir 132 can be obtained, and the composition of the solution in the first reservoir 132 can be analyzed, thereby facilitating the smooth proceeding of the electrosynthesis.

Referring to fig. 1, in some embodiments of the present invention, the second liquid storage bottle 330 is further provided with two second ports 331 communicating with the second liquid storage chamber 332, one second port 331 is used for discharging gas (such as oxygen) generated in the electrolysis process, and the other second port 331 is used for obtaining the solution in the second liquid storage chamber 332.

Therefore, by arranging the second interface 331, the gas generated by the electrolysis of the anode solution in the second solution storage cavity 332 can be discharged in time, and meanwhile, a sample of the solution in the second solution storage cavity 332 can be obtained, so that the components of the solution can be conveniently analyzed.

Referring to fig. 3 and 4, in some embodiments of the present invention, the reaction module 200 further comprises a support tube 260, the support tube 260 is located in the accommodating chamber 212, the support tube 260 is provided with a plurality of through holes 261 penetrating through the inner surface and the outer surface, and the proton exchange membrane 230 is fixed on the inner surface or the outer surface of the support tube 260.

Thus, the support tube 260 can be easily installed to the proton exchange membrane 230, and the through hole 261 can increase the effective area of the proton exchange membrane 230 to improve the efficiency of transferring protons from the anode chamber 214 to the cathode chamber 213.

In a further embodiment of the present invention, the material of the support tube 260 is PVC. PVC is polyvinyl chloride, has the characteristics of high strength and corrosion resistance, can better meet the use requirement, and prolongs the service life of the supporting tube 260.

In some embodiments of the present invention, the anode 240 comprises one of a graphite rod, a titanium wire, and a platinum wire. The graphite rod, the titanium wire and the platinum wire have good conductivity and corrosion resistance, and can better meet the use requirements. Other materials having good conductivity may be used as the anode 240.

In some embodiments of the present invention, the cathode 220 includes one of carbon paper, carbon cloth, carbon felt, copper foam, nickel foam, surface-modified carbon paper, surface-modified carbon cloth, surface-modified carbon felt, surface-modified copper foam, and surface-modified nickel foam. The carbon paper, the carbon cloth, the carbon felt, the foam copper and the foam nickel have the characteristics of small density and thin thickness, and are favorable for increasing the contact area with a cathode solution and reducing the weight of the microbial electrosynthesis reactor. The surface modification method of the electrode material includes acid treatment, alkali treatment, surface plating, addition of a surface modification additive, and the like.

In combination with the above, the reactor for microbial electrosynthesis of the present invention has the following advantages.

First, the structure is compact, the concentric column type reactor configuration is adopted, the distance between the cathode 220 and the anode 240 is greatly reduced, and the ohmic loss caused by the migration of ions in the electrolyte is reduced.

Secondly, the effective area of the cathode 220 is greatly increased, which is beneficial to the attachment of more microorganisms, thereby improving the electron transfer efficiency between the microorganisms and the electrodes and promoting the growth of the cathode biofilm. In addition, the increased surface area of cathode 220 can reduce the current density at the same current, which is beneficial to reduce the electrochemical loss caused by the activation polarization.

Thirdly, the effective area of the proton exchange membrane 230 is greatly increased, thereby promoting the transfer of protons from the anode chamber 214 to the cathode chamber 213, avoiding the pH differentiation between the cathode chamber 213 and the anode chamber 214, reducing the overpotential, and simultaneously reducing the obstruction of the membrane blockage to the transmembrane transfer of protons.

Fourthly, by optimizing the reactor configuration, the electrochemical loss can be reduced, the autotrophic microorganism enrichment of the cathode 220 and the reactor start-up are accelerated, and finally, the reduction of CO by the cathode 220 is improved ₂ Production rate of organic substances such as acetic acid, coulombic efficiency and current density.

The embodiments of the present invention have been described in detail with reference to the drawings, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art. Furthermore, the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.

Claims

1. A microbial electrosynthesis reactor, comprising:

the first circulating assembly comprises a first circulating pipeline, a first circulating pump and a first liquid storage bottle, the first circulating pipeline is provided with a first circulating channel, two ends of the first circulating channel are respectively communicated with the first water inlet hole and the first water outlet hole, the first liquid storage bottle is provided with a first liquid storage cavity, the first liquid storage cavity is used for storing cathode solution, the first liquid storage cavity is communicated in the first circulating channel, and the first circulating pump is used for driving the cathode solution to circularly flow between the first liquid storage cavity and the cathode chamber;

2. The microbial electrosynthesis reactor as recited in claim 1, wherein said cathode is attached to an inner surface of said receiving chamber.

3. The microbial electrosynthesis reactor as defined in claim 1 wherein said housing chamber is cylindrical and said proton exchange membrane and said cathode are both tubular.

4. The reactor according to claim 3, wherein an angle between the axis of the first inlet hole and the axis of the accommodating chamber is an acute angle, and an angle between the axis of the second inlet hole and the axis of the accommodating chamber is an acute angle.

5. The reactor according to claim 1, wherein the first circulation module further comprises a first pH probe, the first reservoir further comprises three first ports communicating with the first reservoir, one of the first ports is inserted with the first pH probe, the first pH probe is used for monitoring the pH of the solution in the first reservoir, another one of the first ports is used for introducing a gas phase substrate, and the last one of the first ports is used for obtaining the solution in the first reservoir.

6. The reactor according to claim 1, wherein the second reservoir is further provided with two second ports communicating with the second reservoir, one of the second ports is used for discharging gas generated during electrolysis, and the other of the second ports is used for obtaining the solution in the second reservoir.

7. The reactor of claim 1, wherein the reaction assembly further comprises a support tube disposed in the receiving chamber, the support tube having a plurality of through holes extending through an inner surface and an outer surface thereof, the proton exchange membrane being secured to the inner surface or the outer surface of the support tube.

8. The microbial electrosynthesis reactor as defined in claim 7 wherein said support tube is comprised of PVC.

9. The microbial electrosynthesis reactor as defined in claim 1 wherein said anode comprises one of a graphite rod, a titanium wire, and a platinum wire.

10. The microbial electrosynthesis reactor as defined in claim 1 wherein said cathode comprises one of carbon paper, carbon cloth, carbon felt, copper foam, nickel foam, surface modified carbon paper, surface modified carbon cloth, surface modified carbon felt, surface modified copper foam, and surface modified nickel foam.