WO2019078003A1

WO2019078003A1 - Microbial fuel cell, liquid processing system, and liquid processing structure

Info

Publication number: WO2019078003A1
Application number: PCT/JP2018/036988
Authority: WO
Inventors: 直毅吉川
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-10-19
Filing date: 2018-10-03
Publication date: 2019-04-25

Abstract

A microbial fuel cell (100) has a liquid processing unit (1), which is provided with an electrode joined body (40) having a positive electrode (10) and a negative electrode (20) that supports anaerobic microbes. The microbial fuel cell (100) further has an aeration unit (90) that aerates the liquid processing unit (1) and removes foreign matter that has adhered to the negative electrode (20). The foreign matter that has adhered to the negative electrode (20) is removed due to air bubbles that are discharged from the aeration unit (90) into a liquid (60) to be processed. A liquid processing system comprises this microbial fuel cell (100).

Description

Microbial fuel cell, liquid processing system, and liquid processing structure

The present invention relates to microbial fuel cells, liquid handling systems, and liquid handling structures. In particular, the present invention relates to a microbial fuel cell capable of purifying wastewater and producing electrical energy, and a liquid treatment system using the microbial fuel cell. The invention further relates to liquid processing structures for use in microbial fuel cells and liquid processing systems.

A microbial fuel cell is an apparatus which oxidizes and decomposes the organic matter while converting the chemical energy of the organic matter contained in the wastewater into electric energy by the catalytic action (metabolic reaction, biochemical conversion) of the microorganism. That is, the microbial fuel cell produces electric energy directly from the organic matter by the action of the microorganism. Therefore, the microbial fuel cell can be expected to improve the energy recovery efficiency as compared with the conventional energy recovery system using the conversion step from organic matter to biogas. Moreover, the microbial fuel cell can be used not only for power generation but also as an incidental facility for waste water treatment, organic waste treatment, organic waste treatment, and the like.

The microbial fuel cell has a negative electrode carrying a microorganism, and a positive electrode in contact with a gas phase containing oxygen and an electrolytic solution (waste water). And while supplying the electrolyte solution containing an organic substance etc. to a negative electrode, the gas containing oxygen is supplied to a positive electrode. The negative electrode and the positive electrode form a closed circuit by being connected to each other through a load circuit. At the negative electrode, hydrogen ions and electrons are generated from the electrolytic solution by the catalytic action of microorganisms. Then, the generated hydrogen ions move to the positive electrode, and the electrons move to the positive electrode through the load circuit. The hydrogen ions and electrons transferred from the negative electrode combine with oxygen at the positive electrode to be consumed as water. At that time, the electrical energy flowing to the closed circuit is recovered.

As such a microbial fuel cell, a closed hollow cassette conventionally having a negative electrode for supporting an anaerobic microorganism by immersing it in an organic substrate, an outer shell formed at least in part by an ion permeable diaphragm, and an inlet / outlet; And are disclosed (see, for example, Patent Document 1). The microbial fuel cell further comprises a positive electrode which is enclosed with the electrolyte in a hollow cassette or is attached to the inside of the diaphragm of the cassette and inserted into the organic substrate. Then, it is also disclosed that oxygen is supplied into the cassette via the inlet / outlet and electricity is taken out via a circuit that electrically connects the negative electrode and the positive electrode.

JP, 2009-93861, A

In microbial fuel cells, anaerobic microorganisms may be supported on the negative electrode by a biofilm. However, when the conventional microbial fuel cell is driven for a long time, there is a problem that the power generation efficiency of the microbial fuel cell is deteriorated because the biofilm on the negative electrode is enlarged.

The present invention has been made in view of the problems of the prior art. And the objective of this invention is providing the liquid processing system using the microbial fuel cell which can suppress the fall of the electric power generation efficiency by the foreign material adhering to the negative electrode, and the said microbial fuel cell. It is also an object of the present invention to provide liquid processing structures for use in microbial fuel cells and liquid processing systems.

In order to solve the above-mentioned subject, a microbial fuel cell concerning the first mode of the present invention is provided with a liquid processing unit provided with an electrode assembly which has an anode carrying an anaerobic microorganism, and an anode. The microbial fuel cell further includes an aeration unit for aerating the liquid processing unit to remove foreign matter attached to the negative electrode.

A liquid treatment system according to a second aspect of the present invention comprises the microbial fuel cell described above.

A liquid processing structure according to a third aspect of the present invention fixes an electrode assembly having an electrode assembly having a negative electrode carrying an anaerobic microorganism and a positive electrode, and forms the gas phase in contact with the positive electrode. And a spacer member. The liquid treatment structure further comprises a diffuser for aerating the liquid treatment unit.

FIG. 1 is a perspective view schematically showing an example of a microbial fuel cell according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a cross-sectional view taken along the line BB in FIG. FIG. 4 is an exploded perspective view showing a liquid processing unit in the microbial fuel cell. FIG. 5 is a cross-sectional view schematically showing another example of the microbial fuel cell according to the embodiment of the present invention. FIG. 6 is a perspective view schematically showing an example of the liquid treatment structure according to the embodiment of the present invention.

Hereinafter, the microbial fuel cell, the liquid treatment system, and the liquid treatment structure according to the present embodiment will be described in detail. The dimensional ratios in the drawings are exaggerated for the convenience of description, and may differ from the actual ratios.

[Microbial fuel cell]
The microbial fuel cell 100 which concerns on this embodiment is equipped with the liquid processing unit 1 which carry | supports microorganisms and the negative electrode 20 electrically connected with the positive electrode 10, as shown in FIG. In addition, the microbial fuel cell 100 is provided with a treatment tank 70 which holds the liquid to be treated 60 containing an organic substance inside and the liquid treatment unit 1 is immersed in the liquid to be treated 60.

Liquid treatment unit
The liquid processing unit 1 includes an electrode assembly 40 including a positive electrode 10, a negative electrode 20, and an ion transfer layer 30, as shown in FIGS. In the liquid processing unit 1, the negative electrode 20 is disposed in contact with one surface 30 a of the ion transfer layer 30, and the positive electrode 10 is disposed in contact with the surface 30 b opposite to the surface 30 a of the ion transfer layer 30. It is done. The gas diffusion layer 12 of the positive electrode 10 is in contact with the ion transfer layer 30, and the water repellent layer 11 is exposed to the gas phase 2 side.

And as shown in FIG. 4, the electrode assembly 40 is laminated | stacked and fixed to the spacer member 50. As shown in FIG. The spacer member 50 is a U-shaped frame member along the outer peripheral portion of the surface 10 a of the positive electrode 10, and the upper portion is open. That is, the spacer member 50 is a frame member in which the bottom surfaces of the two first columnar members 51 are connected by the second columnar member 52. Further, as shown in FIG. 2, the side surface 53 of the spacer member 50 is joined to the outer peripheral portion of the surface 10 a of the positive electrode 10.

As shown in FIG. 2, the liquid processing unit 1 formed by laminating two sets of electrode assemblies 40 and the spacer member 50 is formed inside the processing tank 70 so that the gas phase 2 communicated with the atmosphere is formed. Be placed. A liquid to be treated 60, which is a waste water, is held inside the treatment tank 70, and the gas diffusion layer 12, the negative electrode 20 and the ion transfer layer 30 of the positive electrode 10 are immersed in the liquid to be treated 60.

As described later, the positive electrode 10 is provided with a water repellent layer 11 having water repellency. Therefore, the liquid to be treated 60 held inside the treatment tank 70 and the inside of the spacer member 50 are separated, and the internal space formed by the electrode assembly 40 and the spacer member 50 is the gas phase 2. In the microbial fuel cell 100, the gas phase 2 is opened to the outside air, or air is supplied to the gas phase 2 from the outside by, for example, a pump. Further, as shown in FIG. 2, the positive electrode 10 and the negative electrode 20 are each electrically connected to the external circuit 80.

(Positive electrode)
As shown in FIG. 2, the positive electrode 10 according to the present embodiment is a gas diffusion electrode including a water repellent layer 11 and a gas diffusion layer 12 stacked so as to be in contact with the water repellent layer 11. By using such a thin plate-like gas diffusion electrode, it is possible to easily supply the oxygen in the gas phase 2 to the catalyst in the positive electrode 10.

<Water-repellent layer>
The water repellent layer 11 in the positive electrode 10 is a layer having both water repellency and oxygen permeability. The water repellent layer 11 is configured to allow the movement of oxygen from the gas phase 2 to the liquid phase while satisfactorily separating the gas phase 2 and the liquid phase in the electrochemical system in the liquid treatment unit 1. That is, while the water repellent layer 11 allows oxygen in the gas phase 2 to permeate and move to the gas diffusion layer 12, the liquid 60 can be inhibited from moving to the gas phase 2 side. Here, “separation” means to physically shut off.

The water repellent layer 11 is in contact with the gas phase 2 containing oxygen and diffuses the oxygen in the gas phase 2. The water repellent layer 11 supplies oxygen to the gas diffusion layer 12 substantially uniformly in the configuration shown in FIG. Therefore, it is preferable that the water repellent layer 11 be a porous body so that the oxygen can be diffused. In addition, since the water repellent layer 11 has water repellency, it is possible to prevent the pores of the porous body from being blocked by condensation or the like and the decrease in the diffusion of oxygen being suppressed. Further, since the liquid 60 to be treated is difficult to permeate into the water repellent layer 11, oxygen can be efficiently circulated from the surface of the water repellent layer 11 in contact with the gas phase 2 to the surface facing the gas diffusion layer 12. It becomes possible.

The water repellent layer 11 is preferably formed in a sheet shape. Further, the material constituting the water repellent layer 11 is not particularly limited as long as it has water repellency and oxygen in the gas phase 2 can be diffused. The material constituting the water repellent layer 11 is made of, for example, polyethylene, polypropylene, polybutadiene, nylon, polytetrafluoroethylene (PTFE), ethylcellulose, poly-4-methylpentene-1, butyl rubber and polydimethylsiloxane (PDMS). At least one selected from the group can be used. Since these materials easily form a porous body and also have high water repellency, it is possible to suppress clogging of pores and improve gas diffusivity. The water repellent layer 11 preferably has a plurality of through holes in the stacking direction X of the water repellent layer 11 and the gas diffusion layer 12.

As the water repellent layer 11, for example, a waterproof moisture permeable sheet can be used. As the waterproof moisture-permeable sheet, for example, Cellpore (registered trademark) manufactured by Sekisui Chemical Co., Ltd. and Breslon (registered trademark) manufactured by Nitoms Corporation can be used.

The water repellent layer 11 may be subjected to a water repellent treatment using a water repellent, if necessary, in order to enhance the water repellency. Specifically, a water repellent agent such as polytetrafluoroethylene may be attached to the porous body constituting the water repellent layer 11 to improve the water repellency.

<Gas diffusion layer>
The gas diffusion layer 12 in the positive electrode 10 preferably comprises a porous conductive material and a catalyst supported on the conductive material. The gas diffusion layer 12 may be made of a porous and conductive catalyst. By providing such a gas diffusion layer 12 on the positive electrode 10, it becomes possible to conduct electrons generated by a local cell reaction described later between the catalyst and the external circuit 80. That is, as described later, a catalyst is supported on the gas diffusion layer 12, and the catalyst is an oxygen reduction catalyst. Then, the electrons move from the external circuit 80 to the catalyst through the gas diffusion layer 12 so that the catalyst can promote the oxygen reduction reaction by oxygen, hydrogen ions and electrons.

In the positive electrode 10, in order to ensure stable performance, it is preferable that oxygen permeates the water repellent layer 11 and the gas diffusion layer 12 efficiently and is supplied to the catalyst. Therefore, the gas diffusion layer 12 is preferably a porous body having a large number of pores through which oxygen can permeate from the surface facing the water repellent layer 11 to the surface on the opposite side. Further, the shape of the gas diffusion layer 12 is particularly preferably a three-dimensional mesh shape. With such a mesh shape, it is possible to impart high oxygen permeability and conductivity to the gas diffusion layer 12.

In the positive electrode 10, in order to supply oxygen to the gas diffusion layer 12 efficiently, the water repellent layer 11 is preferably joined to the gas diffusion layer 12 via an adhesive. Thus, the diffused oxygen is directly supplied to the gas diffusion layer 12, and the oxygen reduction reaction can be efficiently performed. The adhesive is preferably provided at least in part between the water repellent layer 11 and the gas diffusion layer 12 from the viewpoint of securing the adhesiveness between the water repellent layer 11 and the gas diffusion layer 12. However, from the viewpoint of enhancing adhesion between the water repellent layer 11 and the gas diffusion layer 12 and supplying oxygen to the gas diffusion layer 12 stably over a long period, the adhesive is the water repellent layer 11 and the gas diffusion layer More preferably, it is provided on the entire surface between 12 and 12.

The adhesive is preferably one having oxygen permeability, and includes at least one selected from the group consisting of polymethyl methacrylate, methacrylic acid-styrene copolymer, styrene-butadiene rubber, butyl rubber, nitrile rubber, chloroprene rubber and silicone. Resin can be used.

Here, the gas diffusion layer 12 of the positive electrode 10 in the present embodiment will be described in more detail. As described above, the gas diffusion layer 12 can be configured to include a porous conductive material and a catalyst supported on the conductive material.

The conductive material in the gas diffusion layer 12 can be made of, for example, one or more materials selected from the group consisting of carbon-based materials, conductive polymers, semiconductors, and metals. Here, the carbon-based substance refers to a substance having carbon as a component. Examples of carbon-based materials include, for example, graphite, activated carbon, carbon black, Vulcan (registered trademark) XC-72R, acetylene black, carbon powder such as furnace black and denka black, graphite felt, carbon wool, carbon woven fabric, etc. Carbon fiber, carbon plate, carbon paper, carbon disk, carbon cloth, carbon foil, carbon-based material obtained by compression molding of carbon particles can be mentioned. In addition, as an example of the carbon-based material, fine structure materials such as carbon nanotubes, carbon nanohorns, and carbon nanoclusters can also be mentioned.

The conductive polymer is a generic term for polymer compounds having conductivity. As the conductive polymer, for example, a single monomer or a polymer of two or more monomers having aniline, aminophenol, diaminophenol, pyrrole, thiophene, paraphenylene, fluorene, furan, acetylene or derivatives thereof as a constitutional unit It can be mentioned. Specifically, examples of the conductive polymer include polyaniline, polyaminophenol, polydiaminophenol, polypyrrole, polythiophene, polyparaphenylene, polyfluorene, polyfuran, polyacetylene and the like. As a metal conductive material, a stainless steel mesh is mentioned, for example. In consideration of availability, cost, corrosion resistance, durability and the like, the conductive material is preferably a carbon-based material.

In addition, the shape of the conductive material is preferably a powder shape or a fiber shape. In addition, the conductive material may be supported by a support. The support refers to a member which itself is rigid and can give the gas diffusion electrode a certain shape. The support may be an insulator or a conductor. When the support is an insulator, examples of the support include glass, plastic, synthetic rubber, ceramics, paper treated with water or water resistance, water repellent or water repellent, plant pieces such as wood pieces, bone pieces, animal pieces such as shells, etc. . Examples of the support having a porous structure include porous ceramic, porous plastic, sponge and the like. When the support is a conductor, examples of the support include carbon paper, carbon fibers, carbon-based materials such as carbon rods, metals, conductive polymers, and the like.

The catalyst in the gas diffusion layer 12 is a platinum-based catalyst, a carbon-based catalyst using iron or cobalt, a transition metal oxide-based catalyst such as partially oxidized tantalum carbonitride (TaCNO) or zirconium carbonitride (ZrCNO), tungsten Alternatively, a carbide-based catalyst using molybdenum, activated carbon or the like can be used.

The catalyst in the gas diffusion layer 12 is preferably a carbon-based material doped with metal atoms. The metal atom is not particularly limited, but titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zirconium, niobium, molybdenum, ruthenium, rhodium, palladium, silver, hafnium, tantalum, tungsten, rhenium, osmium, iridium It is preferable that it is an atom of at least one metal selected from the group consisting of platinum and gold. In this case, the carbon-based material exhibits excellent performance as a catalyst for particularly promoting the oxygen reduction reaction. The amount of metal atoms contained in the carbon-based material may be appropriately set so that the carbon-based material has excellent catalytic performance.

The carbon-based material is preferably further doped with one or more nonmetallic atoms selected from nitrogen, boron, sulfur and phosphorus. The amount of nonmetal atoms doped in the carbon-based material may also be appropriately set so that the carbon-based material has excellent catalytic performance.

The carbon-based material is based on a carbon source material such as graphite and amorphous carbon, and the carbon source material is doped with metal atoms and one or more nonmetal atoms selected from nitrogen, boron, sulfur and phosphorus It is obtained by

The combination of metal atoms and nonmetal atoms doped in the carbon-based material is appropriately selected. In particular, it is preferable that the nonmetal atom contains nitrogen and the metal atom contains iron. In this case, the carbon-based material can have particularly excellent catalytic activity. The nonmetal atom may be only nitrogen or the metal atom may be only iron.

The nonmetal atom may contain nitrogen, and the metal atom may contain at least one of cobalt and manganese. Also in this case, the carbon-based material can have particularly excellent catalytic activity. The nonmetal atom may be only nitrogen. In addition, the metal atom may be only cobalt, only manganese, or only cobalt and manganese.

The shape of the carbon-based material is not particularly limited. For example, the carbon-based material may have a particulate shape or may have a sheet-like shape. The dimensions of the carbon-based material having a sheet-like shape are not particularly limited, and, for example, the carbon-based material may have minute dimensions. The carbonaceous material having a sheet-like shape may be porous. It is preferable that the porous carbon-based material having a sheet-like shape has, for example, a woven-like shape, a non-woven-like shape or the like. Such a carbon-based material can constitute the gas diffusion layer 12 even without the conductive material.

The carbon-based material configured as a catalyst in the gas diffusion layer 12 can be prepared as follows. First, a mixture containing, for example, a nonmetal compound containing at least one nonmetal selected from the group consisting of nitrogen, boron, sulfur, and phosphorus, a metal compound, and a carbon source material is prepared. Then, the mixture is heated at a temperature of 800 ° C. or more and 1000 ° C. or less for 45 seconds or more and less than 600 seconds. Thereby, a carbon-based material configured as a catalyst can be obtained.

Here, as the carbon source material, as described above, for example, graphite or amorphous carbon can be used. Further, the metal compound is not particularly limited as long as it is a compound containing a metal atom which can coordinately bond with a nonmetal atom doped in the carbon source material. Examples of metal compounds include inorganic metal salts such as metal chlorides, nitrates, sulfates, bromides, iodides and fluorides, organic metal salts such as acetates, hydrates of inorganic metal salts, and organic metal salts It is possible to use at least one selected from the group consisting of hydrates of For example, when graphite is doped with iron, the metal compound preferably contains iron (III) chloride. In addition, when graphite is doped with cobalt, the metal compound preferably contains cobalt chloride. When manganese is doped to the carbon source material, the metal compound preferably contains manganese acetate. The amount of the metal compound used is preferably determined so that, for example, the ratio of metal atoms in the metal compound to the carbon source material is in the range of 5 to 30% by mass, and this ratio is further preferably 5 to 20% by mass More preferably, it is determined to be within the range.

The nonmetallic compound is preferably at least one nonmetallic compound selected from the group consisting of nitrogen, boron, sulfur and phosphorus as described above. Examples of nonmetal compounds include pentaethylenehexamine, ethylenediamine, tetraethylenepentamine, triethylenetetramine, octylboronic acid, 1,2-bis (diethylphosphinoethane), triphenyl phosphite, and benzyl disulfide. At least one compound selected from the group consisting of The amount of the nonmetallic compound used is appropriately set according to the doping amount of the nonmetallic atom to the carbon source material. The amount of the nonmetallic compound used is preferably determined such that the molar ratio of the metal atom in the metallic compound to the nonmetallic atom in the nonmetallic compound is in the range of 1: 1 to 1: 2. More preferably, it is determined to be in the range of 1: 1.5 to 1: 1.8.

In the gas diffusion layer 12, the catalyst may be bound to the conductive material using a binder. That is, the catalyst may be supported on the surface of the conductive material and inside the pores using a binder. Thereby, the catalyst can be prevented from being desorbed from the conductive material and the oxygen reduction characteristics can be prevented from being degraded. As the binder, for example, it is preferable to use at least one selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride (PVDF), and ethylene-propylene-diene copolymer (EPDM). It is also preferable to use NAFION (registered trademark) as a binder.

(Negative electrode)
The negative electrode 20 according to the present embodiment has a function of supporting the below-described microorganism and generating hydrogen ions and electrons from at least one of the organic substance and the nitrogen-containing compound in the liquid 60 by catalytic action of the microorganism. . Therefore, the negative electrode 20 is not particularly limited as long as it has a configuration that produces such a function.

The negative electrode 20 has a structure in which microorganisms are supported on a conductive sheet having conductivity. The conductive sheet preferably includes at least one selected from the group consisting of a porous conductive sheet, a woven conductive sheet and a non-woven conductive sheet. The conductor sheet may be a laminate in which a plurality of sheets are laminated. By using a sheet having such a plurality of pores as the conductive sheet of the negative electrode 20, hydrogen ions generated by the later-described local cell reaction easily move in the direction of the ion transfer layer 30, and the oxygen reduction reaction It is possible to increase the speed. Further, from the viewpoint of improving ion permeability, the conductor sheet of the negative electrode 20 has a space (void) continuous in the stacking direction X of the positive electrode 10, the ion transfer layer 30 and the negative electrode 20, that is, the thickness direction. Is preferred.

The conductor sheet may be a metal plate having a plurality of through holes in the thickness direction. Therefore, as a material constituting the conductive sheet of the negative electrode 20, for example, at least one selected from the group consisting of conductive metals such as aluminum, copper, stainless steel, nickel and titanium, carbon paper, and carbon felt is used. be able to.

A graphite sheet may be used as the conductive sheet of the negative electrode 20. In addition, it is preferable that the negative electrode 20 contains graphite, and the graphene layers in the graphite be arranged along the plane in the direction YZ perpendicular to the stacking direction X of the positive electrode 10, the ion transfer layer 30, and the negative electrode 20. By arranging the graphene layers in this manner, the conductivity in the direction YZ perpendicular to the stacking direction X is improved more than the conductivity in the stacking direction X. Therefore, the electrons generated by the local cell reaction of the negative electrode 20 can be easily conducted to the external circuit 80, and the efficiency of the cell reaction can be further improved.

Although the shape of the negative electrode 20 is not particularly limited, it is preferable that the smoothness of the surface, which is an exposed portion, be high, as in a sheet shape. Thereby, when the gas is aerated from the aeration unit 90, the foreign matter can be effectively removed from the surface of the negative electrode 20.

The microorganism carried on the negative electrode 20 is not particularly limited as long as it is a microorganism that decomposes the organic substance or the nitrogen-containing compound in the liquid to be treated 60 to generate hydrogen ions and electrons. As such a microorganism, for example, an aerobic microorganism that requires oxygen for growth or an anaerobic microorganism that does not require oxygen for growth can be used, but it is preferable to use an anaerobic microorganism. Anaerobic microorganisms do not require air for oxidatively decomposing organic substances in the liquid 60 to be treated. Therefore, the power required to feed the air can be significantly reduced. In addition, since the free energy obtained by microorganisms is small, it is possible to reduce the amount of sludge generated.

When the microorganism carried on the negative electrode 20 is an anaerobic microorganism, it is preferable to keep the periphery of the negative electrode 20 in an anaerobic atmosphere in order to enhance the activity of the anaerobic microorganism. Moreover, it is preferable that the anaerobic microorganisms hold | maintained at the negative electrode 20 are electric production bacteria which have an extracellular electron transfer mechanism, for example. Specifically, examples of anaerobic microorganisms include, for example, bacteria belonging to the genus Geobacter, bacteria belonging to the genus Shewanella, bacteria belonging to the genus Aeromonas, bacteria belonging to the genus Geothrix, and bacteria belonging to the genus Saccharomyces.

A microorganism may be held on the negative electrode 20 by overlapping and fixing a biofilm containing the microorganism on the negative electrode 20. Specifically, a biofilm containing microorganisms may be fixed to the surface 20b opposite to the surface 20a in contact with the ion transfer layer 30 in the negative electrode 20 and in direct contact with the liquid 60 to be treated . Biofilm generally refers to a three-dimensional structure including a microbial population and an extracellular polymeric substance (EPS) produced by the microbial population. However, the microorganism may be held by the negative electrode 20 without using the biofilm. The microorganism may be held not only on the surface of the negative electrode 20 but also on the inside.

For example, an electron transfer mediator molecule may be modified in the negative electrode 20. Alternatively, the liquid to be treated 60 in the treatment tank 70 may contain an electron transfer mediator molecule. Thereby, the electron transfer from the microorganism to the negative electrode 20 can be promoted, and more efficient liquid processing can be realized.

Specifically, in the mechanism of metabolism by microorganisms, electrons are exchanged within cells or with the final electron acceptor. When a mediator molecule is introduced into the liquid 60 to be treated, the mediator molecule acts as a final electron acceptor for metabolism and transfers the received electron to the negative electrode 20. As a result, it is possible to increase the rate of oxidative decomposition of the organic substance or the like in the liquid 60 to be treated. Such electron transfer mediator molecules are not particularly limited. As the electron transfer mediator molecule, for example, at least one selected from the group consisting of neutral red, anthraquinone-2,6-disulfonic acid (AQDS), thionine, potassium ferricyanide, and methyl viologen can be used.

(Ion transfer layer)
In the liquid processing unit 1, the electrode assembly 40 is provided between the positive electrode 10 and the negative electrode 20, and further includes an ion transfer layer 30 having proton permeability. Then, as shown in FIGS. 1 and 2, the negative electrode 20 is separated from the positive electrode 10 via the ion transfer layer 30. The ion transfer layer 30 has electrical insulation, and further has a function of transmitting hydrogen ions generated at the negative electrode 20 and moving the hydrogen ions to the positive electrode 10 side.

As the ion transfer layer 30, for example, an ion exchange membrane using an ion exchange resin can be used. As the ion exchange resin, for example, NAFION (registered trademark) manufactured by DuPont Co., Ltd., and Flemion (registered trademark) and Seremion (registered trademark) manufactured by Asahi Glass Co., Ltd. can be used.

Alternatively, as the ion transfer layer 30, a porous membrane having pores through which hydrogen ions can pass may be used. That is, the ion transfer layer 30 may be a sheet having a space (air gap) for hydrogen ions to move from the negative electrode 20 to the positive electrode 10. Therefore, it is preferable that the ion transfer layer 30 includes at least one selected from the group consisting of a porous sheet, a woven sheet and a non-woven sheet. Further, the ion transfer layer 30 may be at least one selected from the group consisting of a glass fiber membrane, a synthetic fiber membrane, and a plastic non-woven fabric, and may be a laminate obtained by laminating a plurality of these. Such a porous sheet has a large number of pores inside, so that hydrogen ions can be easily moved. The pore diameter of the ion transfer layer 30 is not particularly limited as long as hydrogen ions can move from the negative electrode 20 to the positive electrode 10.

As described above, the ion transfer layer 30 has a function of transmitting hydrogen ions generated at the negative electrode 20 and moving the hydrogen ions to the positive electrode 10 side. Therefore, for example, hydrogen ions can move from the negative electrode 20 to the positive electrode 10 if the negative electrode 20 and the positive electrode 10 are close to each other without being in contact with each other. Therefore, in the microbial fuel cell 100, the ion transfer layer 30 is not an essential component. However, by providing the ion transfer layer 30, it is possible to efficiently transfer hydrogen ions from the negative electrode 20 to the positive electrode 10. Therefore, it is preferable to provide the ion transfer layer 30 from the viewpoint of output improvement. A space may be provided between the positive electrode 10 and the ion transfer layer 30, and a space may be provided between the negative electrode 20 and the ion transfer layer 30.

The liquid processing unit 1 is provided with an external circuit 80 electrically connected to the negative electrode 20 and the positive electrode 10 as shown in FIG. However, in the liquid processing unit 1, the negative electrode 20 and the positive electrode 10 may be electrically connected directly by using a conductive member without the external circuit 80. Further, in the liquid processing unit 1, the entire upper part of the spacer member 50 is open, but it may be partially open if air (oxygen) can be introduced into the inside, or it may be closed. It may be

[Treatment tank]
The microbial fuel cell 100 includes a substantially rectangular processing tank 70 that holds the liquid to be treated 60 containing an organic substance therein. An inlet 71 for supplying the liquid to be treated 60 to the treatment tank 70 is provided on the front wall 73 of the treatment tank 70. Further, the rear wall 74 of the processing tank 70 is provided with an outlet 72 for discharging the processed liquid 60 from the processing tank 70.

The liquid to be treated 60 is continuously supplied to the inside of the treatment tank 70 through the inlet 71. Further, as shown in FIGS. 1 and 2, the liquid processing unit 1 is disposed inside the processing tank 70 so as to be immersed in the liquid 60 to be treated. Therefore, the liquid to be treated 60 supplied from the inflow port 71 of the processing tank 70 flows in contact with the liquid processing unit 1 and then is discharged from the outflow port 72.

[Aeration part]
As described above, when the microbial fuel cell is driven for a long time, the biofilm on the negative electrode is enlarged, which may cause a phenomenon in which the power generation efficiency of the microbial fuel cell is reduced. Although the cause of the decrease in the power generation efficiency of the microbial fuel cell by the biofilm has not been fully elucidated, the power generation may be inhibited by the biofilm formed by other microorganisms other than the anaerobic microorganism.

In the present embodiment, the aeration unit 90 is provided in order to remove foreign substances such as enlarged biofilms and enhance power generation efficiency. The aeration unit 90 can aerate the liquid processing unit 1 to remove foreign matter attached to the negative electrode 20. The aeration unit 90 preferably includes an aeration member 91 having a hole for aeration of gas, and a gas supply member 92 for supplying a gas to the hole.

The aeration member 91 is a member having a large number of holes through which gas can flow. Although the diffuser member 91 is not particularly limited, for example, a porous ceramic diffuser plate obtained by bonding coarse ceramic particles with a binder or the like, or a diffuser plate made of a synthetic resin can be used. In addition, a membrane diffuser can also be used as the diffuser member 91.

The gas supply member 92 is a hollow member that holds the diffuser 91 and supplies gas to the holes of the diffuser 91. Then, the gas supplied from the gas supply member 92 passes through the hole of the aeration member 91 to be a bubble, and is diffused into the liquid 60 to be treated.

It is preferable that a pipe 93 for supplying gas from the outside of the processing tank 70 be connected to the aeration unit 90. Specifically, it is preferable that a hollow pipe 93 be connected to the lower surface of the gas supply member 92. The pipe 93 penetrates the rear wall 74 of the processing tank 70 and extends to the outside of the processing tank 70. The end of the pipe 93 is connected to a compressor 94 for pressure-feeding the gas.

As shown in FIGS. 2 and 3, the aeration unit 90 is preferably provided on the lower side of the liquid processing unit 1 in the vertical direction Y. As a result, air bubbles generated from the aeration unit 90 rise along the lower surface of the liquid processing unit 1 and the surface 20 b of the negative electrode 20 and reach the water surface 61 of the liquid 60 to be treated. At this time, since the air bubbles contact the surface 20 b of the negative electrode 20, foreign matter on the negative electrode 20 can be removed.

In the microbial fuel cell 100, the number of aeration parts 90 is not particularly limited. For example, as shown in FIG. 2, one aeration unit 90 may be provided on the lower side of one liquid processing unit 1. Further, as shown in FIG. 5, a plurality of aeration units 90 may be provided on the lower side of one liquid processing unit 1. Specifically, the aeration unit 90 may be provided on the lower side of the two negative electrodes 20 provided in the liquid processing unit 1. Furthermore, as shown in FIG. 6, one air diffuser 90 may be provided for a plurality of liquid processing units 1.

The gas diffused from the aeration unit 90 to the liquid to be treated 60 is not particularly limited. For example, air can be used as the gas. However, as described above, in order to enhance the activity of the anaerobic microorganism, it is preferable to keep the periphery of the negative electrode 20 in an anaerobic atmosphere. Therefore, it is preferable that the gas to be diffused be a gas not containing oxygen, for example, it is preferable to use nitrogen.

Next, the operation of the microbial fuel cell 100 of the present embodiment will be described. When the electrode assembly 40 including the positive electrode 10, the negative electrode 20, and the ion transfer layer 30 is immersed in the liquid 60, the gas diffusion layer 12, the negative electrode 20, and the ion transfer layer 30 of the positive electrode 10 are immersed in the liquid 60, At least a part of the water repellent layer 11 is exposed to the gas phase 2.

At the time of operation of the microbial fuel cell 100, a liquid to be treated 60 containing at least one of an organic substance and a nitrogen-containing compound is supplied to the negative electrode 20, and air is supplied to the positive electrode 10. At this time, air is continuously supplied through the opening provided at the top of the spacer member 50.

Then, in the positive electrode 10, oxygen permeates the water repellent layer 11 and diffuses into the gas diffusion layer 12. In the negative electrode 20, hydrogen ions and electrons are generated from at least one of the organic substance and the nitrogen-containing compound in the liquid to be treated 60 by the catalytic action of microorganisms. The generated hydrogen ions permeate the ion transfer layer 30, move to the positive electrode 10 side, and reach the gas diffusion layer 12 in the positive electrode 10. The generated electrons move to the external circuit 80 through the conductor sheet of the negative electrode 20, and further move to the gas diffusion layer 12 of the positive electrode 10 from the external circuit 80. The hydrogen ions and electrons are combined with oxygen by the action of the catalyst in the gas diffusion layer 12 and consumed as water. At this time, the external circuit 80 recovers the electrical energy flowing to the closed circuit. Thus, the liquid processing unit 1 can decompose at least one of the organic substance and the nitrogen-containing compound in the liquid to be treated 60 by the action of the microorganism on the negative electrode 20.

Here, when the microbial fuel cell 100 is driven for a long time and the biofilm on the negative electrode 20 is enlarged, air bubbles are released from the aeration unit 90 to the liquid 60 to be treated. Specifically, the compressor 94 is operated to feed gas to the pipe 93. The pumped gas passes through the inside of the pipe 93 and reaches the gas supply member 92 of the aeration unit 90. The gas supplied to the gas supply member 92 passes through the holes of the aeration member 91 to form air bubbles and diffuses into the liquid 60 to be treated.

The air bubbles diffused from the air diffusion member 91 to the liquid to be treated 60 float along the lower surface of the liquid treatment unit 1 and the surface 20 b of the negative electrode 20 and reach the water surface 61 of the liquid to be treated 60. At this time, since the air bubbles contact the surface 20 b of the negative electrode 20, the negative electrode 20 can be vibrated. Moreover, the swirling flow is generated in the vicinity of the surface 20 b of the negative electrode 20 due to the rise of the air bubble. The vibration of the negative electrode 20 and the swirling flow generated in the vicinity of the surface 20 b of the negative electrode 20 make it possible to peel off and remove foreign substances on the surface of the negative electrode 20, that is, the enlarged biofilm.

The timing at which the aeration unit 90 aerates is not particularly limited, and can be performed when the foreign matter on the surface of the negative electrode 20 needs to be removed. However, as shown in FIG. 2, the microbial fuel cell 100 preferably further includes a control unit 110 that controls the timing of removing foreign matter attached to the negative electrode 20 by the aeration unit 90.

In the microbial fuel cell 100, the control unit 110 may be interlocked with the liquid processing unit 1. As described above, when the microbial fuel cell 100 is in operation, electrons generated at the negative electrode 20 move to the positive electrode 10 through the external circuit 80. Therefore, in the liquid processing unit 1, electrical energy can be obtained at the time of processing the liquid to be treated 60. Therefore, the control unit 110 may sense that the power generation efficiency of the liquid processing unit 1 is decreasing, and the control unit 110 may operate the compressor 94 based on the result. For example, when the control unit 110 senses that the voltage in the external circuit 80 has fallen below a predetermined value, the control unit 110 may operate the compressor 94 and cause the aeration unit 90 to aerate.

Thus, the microbial fuel cell 100 includes the liquid processing unit 1 including the electrode assembly 40 having the negative electrode 20 carrying the anaerobic microorganism and the positive electrode 10. The microbial fuel cell 100 further includes an aeration unit 90 for aerating the liquid processing unit 1 and removing foreign matter attached to the negative electrode 20. In addition, the microbial fuel cell 100 further includes a treatment tank that holds the liquid to be treated 60 inside, and the liquid treatment unit 1 and the aeration unit 90 are immersed in the liquid to be treated 60. Then, the foreign matter attached to the negative electrode 20 is removed by the air bubbles released from the aeration unit 90 into the liquid to be treated 60. Therefore, even when the microbial fuel cell 100 is driven for a long period of time, foreign matter attached to the negative electrode 20, for example, an enlarged biofilm can be removed, so that the power generation efficiency can be maintained high.

In addition, the configuration of the aeration unit 90 is not limited to the configuration including the above-described aeration member 91 and the gas supply member 92, and any configuration that can aerate the liquid 60 to be treated can be applied. . Specifically, when generating coarse air bubbles, a porous tube made of metal or synthetic resin, or a disk diffuser may be used as the aeration unit 90.

As described above, the aeration unit 90 is connected to the pipe 93 for supplying gas from the outside of the processing tank 70. The method of arranging the pipe 93 is not particularly limited, but may be arranged in contact with the bottom wall 77 of the processing tank 70, for example. Further, in FIG. 1 and FIG. 2, the pipe 93 is disposed on the bottom wall 77 through the rear wall 74. However, the present invention is not limited to such an embodiment. For example, the pipe 93 may be penetrated from the lower surface of the bottom wall 77 and directly connected to the aeration unit 90. Also, the pipe 93 may be disposed along the bottom wall 77 and the rear wall 74 and may be directly connected to the aeration unit 90. That is, the pipe 93 may be disposed along the wall of the processing tank 70 without penetrating the wall of the processing tank 70.

In the microbial fuel cell 100, the liquid processing unit 1 includes a spacer member 50 for fixing the electrode assembly 40 and forming the gas phase 2 in contact with the positive electrode 10. However, in the microbial fuel cell of the present embodiment, the spacer member 50 is not an essential component. That is, if the positive electrode 10 is in contact with the gas phase 2 and the negative electrode 20 is immersed in the liquid 60 to be treated, the electric substance is obtained while decomposing the organic substance and / or the nitrogen-containing compound in the liquid 60 to be treated. Can. For example, even when the positive electrode 10 is floated on the water surface 61 and the negative electrode 20 is sunk in the liquid 60, a part of the positive electrode 10 can be in contact with the gas phase 2 and the negative electrode 20 can be in contact with the liquid 60 .

In the drawings, the positive electrode 10, the negative electrode 20, and the ion transfer layer 30 are formed in a rectangular shape. However, these shapes are not particularly limited, and can be arbitrarily changed according to the size of the microbial fuel cell 100, and the desired power generation performance and purification performance. Also, the area of each layer can be arbitrarily changed as long as the desired function can be exhibited.

[Liquid Handling Structure]
Next, the liquid processing structure according to the present embodiment will be described. As shown in FIG. 6, the liquid treatment structure 200 according to the present embodiment includes the liquid treatment unit 1 and the aeration unit 90 for aerating the liquid treatment unit 1.

In the microbial fuel cell 100 shown in FIG. 1, since the liquid processing unit 1 and the aeration unit 90 are formed as separate members, they need to be installed inside the processing tank 70, respectively. On the other hand, the liquid processing structure 200 includes the liquid processing unit 1 and the aeration unit 90, and the liquid processing unit 1 and the aeration unit 90 are integrally formed. That is, the liquid processing unit 1 and the aeration unit 90 are unitized. Therefore, by inserting the liquid processing structure 200 into the inside of the processing tank 70, the liquid processing unit 1 and the aeration unit 90 can be installed at predetermined positions inside the processing tank, so that the microbial fuel cell can be achieved by a simple construction. Can be manufactured.

As shown in FIG. 6, the liquid treatment structure 200 includes an outer frame 220 as a fixing member 210 in addition to the liquid treatment unit 1 and the aeration unit 90. The outer frame 220 is formed in a substantially rectangular shape by a pillar material. Specifically, the outer frame 220 is formed by connecting the substantially rectangular upper frame 221 and the lower frame 222 by four erected columns 223. Furthermore, the lower frame 222 is formed in a lattice shape by the lattice material 224.

A plurality of liquid processing units 1 are inserted into the inside of the outer frame 220, and the liquid processing unit 1 is fixed to the outer frame 220 via a connection member. Specifically, the spacer member 50 of the liquid processing unit 1 is fixed to the upper frame 221 of the outer frame 220 via the bracket 225. The liquid processing unit 1 is fixed to the outer frame 220 so that the upper portion of the spacer member 50 is open, as shown in FIG. And the aeration part 90 is installed in the cross | intersection part of the grating | lattice material 224 in the lower frame 222. As shown in FIG.

The liquid treatment structure 200 may be provided with a pipe 93 connected to the aeration unit 90. Specifically, the pipe 93 may be provided along the grid member 224 of the lower frame 222. In addition to the pipe 93 connected to the aeration unit 90, the liquid treatment structure 200 may be provided with at least one of the compressor 94 and the control unit 110. However, since the pipe 93 may be installed in the processing tank 70, the pipe 93 is not an essential component of the liquid processing structure 200. Further, since the compressor 94 and the control unit 110 may be installed outside the treatment tank 70 or the treatment tank 70, the compressor 94 and the control unit 110 are not essential components of the liquid treatment structure 200.

Thus, the liquid processing structure 200 fixes the electrode assembly 40 having the negative electrode 20 carrying the anaerobic microorganism and the positive electrode 10, and the electrode assembly 40, and the gas phase 2 in contact with the positive electrode 10 The liquid processing unit 1 is provided with the spacer member 50 to be formed. The liquid treatment structure 200 further includes an aeration unit 90 for aerating the liquid treatment unit 1. In the liquid processing structure 200, the liquid processing unit 1 and the aeration unit 90 are integrally formed by the fixing member 210. For this reason, by inserting the liquid processing structure 200 into the inside of the processing tank 70, the liquid processing unit 1 and the aeration unit 90 can be installed, so that the microbial fuel cell can be obtained by a simple method.

In addition, in the liquid treatment structure 200 shown in FIG. 6, although the fixing member 210 is formed using a pillar material, this embodiment is not limited to such an aspect. For example, the fixing member 210 may use a plate material. Further, the shape of the fixing member 210 is not limited to a substantially rectangular shape, and any shape can be used as long as the liquid processing unit 1 and the aeration unit 90 can be fixed.

Liquid Handling System
Next, the liquid processing system according to the present embodiment will be described. The liquid processing system of the present embodiment includes the above-described microbial fuel cell.

As described above, the microbial fuel cell 100 of the present embodiment supplies the negative electrode 20 with the liquid to be treated 60 containing at least one of the organic substance and the nitrogen-containing compound. Then, carbon dioxide and nitrogen are generated from the organic substance and / or the nitrogen-containing compound in the liquid to be treated 60 together with hydrogen ions and electrons by the metabolism of the microorganism supported on the negative electrode 20.

Specifically, for example, when the liquid 60 to be treated contains glucose as an organic substance, carbon dioxide, hydrogen ions and electrons are generated by the following local cell reaction.
Negative electrode 20 (anode): C ₆ H ₁₂ O ₆ + 6H ₂ O → 6CO ₂ + 24H ⁺ + 24e ⁻
· Positive electrode 10 _{^{(cathode): 6O 2 + 24H + +}} 24e - → 12H 2 O
When the liquid 60 to be treated contains ammonia as a nitrogen-containing compound, nitrogen, hydrogen ions and electrons are generated by the following local cell reaction.
Negative electrode 20 (anode): 4 NH ₃ → 2 N ₂ + 12 H ⁺ + 12 e ⁻
· Positive electrode 10 _{^{(cathode): 3O 2 + 12H + +}} 12e - → 6H 2 O

As described above, in the liquid processing system according to the present embodiment, the organic fuel and the nitrogen-containing compound in the liquid to be treated 60 are in contact with the negative electrode 20 and oxidized and decomposed by using the microbial fuel cell 100. Can be purified. Further, as described above, the treatment liquid 70 is provided with the inflow port 71 for supplying the liquid to be treated 60 and the outflow port 72 for discharging the liquid to be treated 60 after treatment. Are supplied continuously. Therefore, it is possible to treat the liquid to be treated 60 efficiently by bringing the liquid to be treated 60 into contact with the negative electrode 20 continuously.

The liquid treatment system can be widely applied to the treatment of a liquid containing an organic substance, for example, wastewater generated from factories of various industries, and organic wastewater such as sewage. It can also be used to improve the environment of water areas.

Hereinafter, the present embodiment will be described in more detail by way of examples, but the present embodiment is not limited to these examples.

First, a silicone resin which is an adhesive agent is applied to a water repellent layer made of polyolefin and then a graphite foil which is a gas diffusion layer is joined to produce a laminated sheet consisting of water repellent layer / silicone adhesive / gas diffusion layer did. As the water repellent layer, Cellpore (registered trademark) manufactured by Sekisui Chemical Co., Ltd. was used. As the silicone resin, one-component RTV rubber KE-3475-T manufactured by Shin-Etsu Chemical Co., Ltd. was used. The graphite foil used was manufactured by Hitachi Chemical Co., Ltd.

Next, a gas diffusion electrode was produced by press-forming a catalyst layer formed by mixing an oxygen reduction catalyst and PTFE (manufactured by Aldrich) on the surface of the graphite foil opposite to the water repellent layer. In addition, the oxygen reduction catalyst was press-molded so that a basis weight might be 6 mg / cm < ² >.

The oxygen reduction catalyst was prepared as follows. First, a mixed solution was prepared by placing 3 g of carbon black, a 0.1 M aqueous solution of iron (III) chloride, and an ethanol solution of 0.15 M pentaethylenehexamine in a container. As carbon black, ketjen black ECP600 JD manufactured by Lion Specialty Chemicals Co., Ltd. was used. The amount of use of the 0.1 M aqueous solution of iron (III) chloride was adjusted so that the ratio of iron atoms to carbon black was 10% by mass. The total volume was adjusted to 9 mL by further adding ethanol to this mixture. Then, the mixture was ultrasonically dispersed and then dried at a temperature of 60 ° C. in a drier. This yielded a sample containing carbon black, iron (III) chloride, and pentaethylenehexamine.

The sample was then packed into one end of a quartz tube, which was then purged with argon in the quartz tube. The quartz tube was put into a furnace at 900 ° C. and pulled out in 45 seconds. When inserting the quartz tube into the furnace, the temperature rising rate of the sample at the start of heating was adjusted to 300 ° C./s by inserting the quartz tube into the furnace over 3 seconds. Subsequently, the sample was cooled by flowing argon gas through the quartz tube. Thus, an oxygen reduction catalyst was obtained.

Next, as shown in FIG. 1, liquid treatment is carried out by laminating the obtained positive electrode comprising a gas diffusion electrode, an ion transfer layer, and a negative electrode comprising a carbon material (graphite foil) on a U-shaped spacer member. I got a unit.

A treatment vessel having an inlet and an outlet and having a volume of 300 cc was prepared, and an aeration unit having a large number of holes was provided on the bottom of the treatment vessel. Furthermore, one end of the pipe was connected to the aeration part. The other end of the pipe was connected to an air pump provided outside the treatment tank. And as shown in FIG. 1, the liquid processing unit was installed in the inside of the processing tank provided with the aeration part.

Next, the treatment liquid was filled in the treatment tank so as to be in contact with the positive electrode, the negative electrode, and the ion transfer layer. As a liquid to be treated, a model waste liquid having a total organic carbon (TOC) of 500 mg / L was used. Furthermore, in order to stabilize the proton supply property of the liquid to be treated, sodium hydrogencarbonate was added as a buffer to a concentration of 20 mM. Furthermore, soil microorganisms were planted on the negative electrode as a source of anaerobic microorganisms that generate electricity.

Then, the liquid to be treated was supplied to the treatment tank so that the hydraulic retention time was 24 hours. Furthermore, the liquid to be treated was adjusted to have a water temperature of 30 ° C. And the microbial fuel cell of this example was obtained by connecting a positive electrode and a negative electrode to a load circuit.

As a result of operating the obtained microbial fuel cell for 2 months or more, the enlarged biofilm was visually confirmed on the surface of the negative electrode. Therefore, the air pump was operated to pump air to the aeration unit, and aeration processing was performed for several tens of seconds. As a result, peeling of the biofilm on the negative electrode surface was confirmed. Also, output per electrode area before aeration treatment was the 50 mW / m ^2, output per electrode area after aeration was confirmed to be doubled to 95mW / m ^2.

From this result, it is understood that the power generation efficiency of the microbial fuel cell is greatly improved by aeration of the liquid processing unit using the aeration unit and removal of foreign matter (biofilm) adhering to the negative electrode.

As mentioned above, although this embodiment was described, this embodiment is not limited to these, A various deformation | transformation is possible within the range of the summary of this embodiment.

The entire contents of Japanese Patent Application No. 2017-202596 (filing date: October 19, 2017) are incorporated herein by reference.

According to the present disclosure, a microbial fuel cell capable of suppressing a decrease in power generation efficiency due to foreign matter attached to a negative electrode, a liquid processing system using the microbial fuel cell, and a microbial fuel cell and a liquid processing system A liquid handling structure can be provided.

Reference Signs List 1 liquid processing unit 2 gas phase 10 positive electrode 20 negative electrode 30 ion transfer layer 40 electrode assembly 50 spacer member 60 liquid to be treated 70 treatment tank 90 aeration unit 100 microbial fuel cell 110 control unit 200 liquid treatment structure

Claims

A liquid processing unit comprising an electrode assembly having a negative electrode carrying an anaerobic microorganism and a positive electrode;
An aeration unit for aerating the liquid processing unit and removing foreign matter adhering to the negative electrode;
, A microbial fuel cell.
The microbial fuel cell according to claim 1, wherein the liquid processing unit further comprises a spacer member that fixes the electrode assembly and forms a gas phase in contact with the positive electrode.
The aeration unit is provided on the lower side of the liquid processing unit in the vertical direction.
The microbial fuel cell of Claim 1 or 2.
The microbial fuel cell according to any one of claims 1 to 3, wherein the liquid processing unit and the aeration part are integrally formed.
The said aeration part is provided with the aeration member which has a hole for aeration of gas, and the gas supply member which supplies the said gas to the said hole. Microbial fuel cell as described.
The microbial fuel cell as described in any one of the Claims 1 thru | or 5 further equipped with the control part which controls the timing which removes the foreign material adhering to the said negative electrode by the said aeration part.
The liquid processing unit and the aeration unit are immersed in the liquid to be treated, and the foreign matter attached to the negative electrode is removed by the air bubbles released from the aeration unit to the liquid to be treated. A microbial fuel cell according to any one of the preceding claims.
The microbial fuel cell according to any one of claims 1 to 7, wherein the electrode assembly is provided between the positive electrode and the negative electrode, and further comprising an ion transfer layer having proton permeability.
It further comprises a treatment tank for holding the liquid to be treated inside;
The microbial fuel cell according to any one of claims 1 to 8, wherein the liquid processing unit and the aeration unit are immersed in the liquid to be treated.
A liquid treatment system comprising the microbial fuel cell according to any one of the preceding claims.
A liquid processing unit comprising: an electrode assembly having a negative electrode carrying an anaerobic microorganism and a positive electrode; and a spacer member for fixing the electrode assembly and forming a gas phase in contact with the positive electrode.
An aeration unit for aerating the liquid processing unit;
A liquid handling structure comprising: