Abstract: A microbial fuel cell contains a negative electrode including a sheet-like first carbon material including a graphene sheet, the negative electrode supporting microorganisms, and a positive electrode opposed to the negative electrode. The negative electrode has an arithmetical mean roughness Ra on the surface thereof set in a range of 4.0 ?m to 10000 ?m. A waste liquid treatment system includes the microbial fuel cell, wherein the positive electrode is arranged in contact with gas containing oxygen. The microbial fuel cell can be deformed into a shape so as to have high resistance to water pressure. The microbial fuel cell can also increase in the amount of microorganisms supported on the negative electrode due to the high arithmetical mean roughness Ra, so as to enhance output power of the microbial fuel cell.

Abstract: A carbon-based material includes an expanded graphite sheet including expanded graphite grains. The carbon-based material also includes nonmetal atoms or nonmetal ions of a nonmetallic element of either nitrogen or sulfur, and surfaces of the expanded graphite grains are doped with the nonmetal atoms or the nonmetal ions. The carbon-based material also includes metal atoms or metal ions of at least one metallic element selected from the element group of group 8 to group 11 of the periodic table, and the surfaces of the expanded graphite grains are doped with the metal atoms or the metal ions. An electrode includes the carbon-based material, and a microbial fuel cell includes the electrode.

Abstract: An electrode (10) includes: a first diffusion layer (1) having water repellency and oxygen permeability; and a second diffusion layer (2) that supports a catalyst (4) and is laminated on the first diffusion layer. Then, the second diffusion layer includes a carbon material having a sheet shape. A fuel cell (100) includes: an anode (20) that supports microorganisms; and a cathode (40) composed of the electrode (10). A water treatment device includes: the anode (20) that supports microorganisms purifying a liquid to be treated; and the cathode (40) composed of the electrode (10).

Abstract: A microbial fuel cell (100) includes: a positive electrode (10, 10A); a negative electrode (20) that holds microorganisms; and an electrolysis solution (70). The positive electrode includes: an electric conductor layer (1): a porous body layer (2) that is laminated on the electric conductor layer and supports a catalyst (3) therein; and a water-repellent layer (4) that is laminated on a surface (1b) of the electric conductor layer, which is opposite of a surface (1a) thereof in contact with the porous body layer, or a surface (2b) of the porous body layer, which is opposite of a surface (2a) thereof in contact with the electric conductor layer. Then, the porous body layer and the negative electrode are immersed in the electrolysis solution, and at least a part of the water-repellent layer is exposed to a gas phase (90).

Abstract: A gas diffusion electrode (10) includes: a water-repellent layer (1) that is formed of a woven fabric or a nonwoven fabric and has water repellency; and an adhesive layer (2) laminated on one surface of the water-repellent layer. Moreover, the gas diffusion electrode includes a gas diffusion layer (3) laminated on a surface of the adhesive layer, the surface being opposite of the surface facing the water-repellent layer. Then, the adhesive layer is non-biodegradable, and is alkali-resistant. A microbial fuel cell (100) includes: a negative electrode (20) that supports microorganisms; an ion-permeable membrane (30) that allows permeation of hydrogen ions; and a positive electrode (40) including the gas diffusion electrode, the positive electrode being separated from the negative electrode via the ion-permeable membrane.

Abstract: An electrode includes a first diffusion layer (11) having water repellency and functioning to diffuse oxygen, and a second diffusion layer (13) supporting a catalyst layer (30) thereon and functioning to diffuse oxygen. The electrode further includes an electrically conductive layer (12, 15) including a metal material (20, 21) and an oxygen-permeable material, and interposed between the first diffusion layer and the second diffusion layer. A fuel cell (100) and a water treatment equipment each include: an anode (3); an ion transfer layer (4) having proton permeability; and a cathode (1, 2) being the electrode described above, and separated from the anode with the ion transfer layer interposed therebetween.

Abstract: An electrode assembly includes a hollow member having a hollow portion, an oxygen supply portion that supplies oxygen to the hollow portion, and an oxygen permeable portion that allows permeation of oxygen supplied to the hollow portion. Moreover, the electrode assembly includes: an electrode that is provided on an outside of the hollow member in the oxygen permeable portion and is composed by laminating a water-repellent layer having oxygen permeability and an electrically conductive layer on each other from the oxygen permeable portion side; and a buffer member that is provided in the hollow portion and has pressure resistance. Then, the electrode assembly is provided with air permeability from the oxygen supply portion to the oxygen permeable portion. A microbial fuel cell includes: the electrode assembly; and a negative electrode that supports microorganisms.

Abstract: A microbial fuel cell includes a container unit and an electrode unit. The container unit includes an electrolytic cell and a communication port. The electrode unit includes a gas-phase chamber, a positive electrode, a negative electrode that is configured to hold microbes, an ion transfer layer that is interposed between the positive electrode and the negative electrode, a first vent port, and a second vent port. The gas-phase chamber is communicated with the communication port through the second vent port.

Abstract: An electrode structure includes: a water-repellent layer which is permeable to oxygen; and an electric conductor layer which is laid on the water-repellent layer and holds an oxygen reduction catalyst. The electrode structure further includes a filter layer that is laid on a surface of the electric conductor layer on the opposite side of a surface on which the water-repellent layer is laid. The filter layer includes plural through holes with a diameter of 0.01 ?m to 0.5 ?m. The configuration prevents microorganisms from entering the electrode structure, and the microbial fuel cell is therefore able to stably produce electric energy.

Abstract: A carbon-based material according to the present invention contains dopant atoms of metal and non-metal such as nitrogen. In a radial distribution function obtained by Fourier transform of a K-edge EXAFS of the metal, a ratio of “A” to “B” is equal to or more than 4.0, wherein “A” denotes an intensity of the highest one of peaks around a distance equal to a coordinate bond length between atoms of the metal and the non-metal and “B” denotes an intensity of the highest one of peaks around a distance equal to a metallic bond length between atoms of the metal. Note that when the metal is platinum, in a radial distribution function obtained by Fourier transform of an LIII-edge EXAFS of the platinum, a ratio of “A” to “B” is equal to or more than 4.0.

Abstract: A microbial fuel cell system includes: a supply-drain compartment to which an electrolysis solution is supplied and from which the electrolysis solution is drained; a negative electrode soaked in the electrolysis solution and holding electricity-producing bacteria on a surface thereof; and a positive electrode soaked in the electrolysis solution, including at least a part exposed to a gas phase, and holding nitrifying bacteria on a surface thereof excluding the part exposed to the gas phase. At least one of the surface of the positive electrode excluding the part exposed to the gas phase and the electrolysis solution holds denitrifying bacteria.

Abstract: A microbial fuel cell system includes a supply-drain compartment having a supply port and a drain port of an electrolytic solution. The microbial fuel cell system further includes one or more power generation cassettes provided in the supply-drain compartment and each including a microbial fuel cell including: a positive electrode including a first water-repellent layer in contact with a gas phase and a gas diffusion layer attached to the first water-repellent layer; and a negative electrode holding anaerobic microorganisms. The microbial fuel cell system includes one or more purifying cassettes provided in the supply-drain compartment and each including a second water-repellent layer in contact with the gas phase. The power generation cassettes are arranged on the upstream side in a direction in which the electrolytic solution flows from the supply port toward the drain port, and the purifying cassettes are arranged on the downstream side of the power generation cassettes.

Abstract: An electrode (10) includes a first diffusion layer (1) having water repellency, a second diffusion layer (2) supporting a catalyst (4) thereon, and an oxygen-permeable layer (3) having oxygen permeability and interposed between the first diffusion layer and the second diffusion layer. The second diffusion layer includes a sheet-like carbon material. A fuel cell (100) includes an anode (20) supporting microorganisms, an ion transfer layer (30) permeable to hydrogen ions, and a cathode (40) being the electrode (10) and separated from the anode with the ion transfer layer interposed therebetween.

Abstract: A liquid treatment unit (1) includes: an electrical conductor (5) including a first surface (2) and a second surface (3), and a space (4) provided between the first surface and the second surface in which hydrogen ions move; and a structure (6) arranged on the second surface to regulate an oxygen supply amount. A liquid treatment device (10) includes the liquid treatment unit, and a treatment tank (7) which keeps a liquid (9) to be treated, wherein the first surface of the electrical conductor in the liquid treatment unit is located inside the treatment tank.

Abstract: An electrode includes a first diffusion layer (11) having water repellency and functioning to diffuse oxygen, and a second diffusion layer (13) supporting a catalyst layer (30) thereon and functioning to diffuse oxygen. The electrode further includes an electrically conductive layer (12, 15) including a metal material (20, 21) and an oxygen-permeable material, and interposed between the first diffusion layer and the second diffusion layer. A fuel cell (100) and a water treatment equipment each include: an anode (3); an ion transfer layer (4) having proton permeability; and a cathode (1, 2) being the electrode described above, and separated from the anode with the ion transfer layer interposed therebetween.

Abstract: A gas diffusion electrode includes: a water-repellent layer which includes a woven fabric or a non-woven fabric, and which has water repellency; a gas diffusion layer which is stacked on the water-repellent layer; and a catalyst layer which is disposed opposite the water-repellent layer relative to the gas diffusion layer.

Abstract: A microbial fuel cell includes a container unit and an electrode unit. The container unit includes an electrolytic cell and a communication port. The electrode unit includes a gas-phase chamber, a positive electrode, a negative electrode that is configured to hold microbes, an ion transfer layer that is interposed between the positive electrode and the negative electrode, a first vent port, and a second vent port. The gas-phase chamber is communicated with the communication port through the second vent port.

Abstract: A carbon-based material according to the present invention contains dopant atoms of metal and non-metal such as nitrogen. In a radial distribution function obtained by Fourier transform of a K-edge EXAFS of the metal, a ratio of “A” to “B” is equal to or more than 4.0, wherein “A” denotes an intensity of the highest one of peaks around a distance equal to a coordinate bond length between atoms of the metal and the non-metal and “B” denotes an intensity of the highest one of peaks around a distance equal to a metallic bond length between atoms of the metal. Note that when the metal is platinum, in a radial distribution function obtained by Fourier transform of an LIII-edge EXAFS of the platinum, a ratio of “A” to “B” is equal to or more than 4.0.