JP2012107331A - Water electrolysis system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water electrolysis system capable of suppressing a deterioration phenomenon due to electrical treatment when electrically treating water to produce radical oxygen water.SOLUTION: The water electrolysis system includes a water supply part, an electrolyte supplying part, and a water electrolyzer 1. The water supply part supplies water. The electrolyte supplying part supplies electrolyte. The water electrolyzer 1 in which water is supplied to an anode, and electrolyte is supplied to a cathode, performs treatment which electrolyzes water, and sends out water after the treatment. In the water electrolyzer 1, a solid electrolyte membrane 10 and a cathode 8 are separately prepared. The electrolyte supplied to the cathode 8 contains a chlorine ion. A concentration of the chlorine ion is at least 50 mg/L and at most a saturated concentration.

Description

  The present invention relates to a water electrolysis system, and more particularly to a water electrolysis system for treating water by electrolysis.

  An electrolyzer is known as a technique for electrolyzing water. A conventional electrolysis apparatus uses a sandwich structure in which one surface of an ion conductive membrane (solid (polymer) electrolyte membrane) is in contact with the anode and the other surface is in contact with the cathode. That is, both surfaces of the ion conductive film are in close contact with the anode and the cathode, respectively. When electrolysis of water is performed in an electrolytic apparatus having such a structure, hydrogen is generated on the cathode side and oxygen is generated on the anode side. Therefore, in order to release generated hydrogen and oxygen, it is indispensable to use porous or net-like electrodes as the cathode and the anode. As an example of such a structure, there is JP-A-2004-353033 (hereinafter referred to as Patent Document 1).

  Patent Document 1 discloses a membrane / electrode assembly for water electrolysis and a water electrolysis apparatus using the membrane / electrode assembly. The water electrolysis membrane / electrode assembly includes a solid polymer electrolyte membrane, an oxygen electrode joined to one side of the solid polymer electrolyte membrane, and a hydrogen electrode joined to the other side. The oxygen electrode is a porous sheet-like carbon material plated with iridium, and a coating of a mixture containing carbon and a resin for the solid polymer membrane formed on the surface of the sheet-like carbon material in contact with the solid polymer electrolyte membrane. Including layers. The hydrogen electrode includes a porous sheet-like carbon material, a coating layer of a mixture containing carbon and a resin for a solid polymer film formed on the sheet-like carbon material, and further Pt (alloy) and Pt (alloy) and And / or a coating layer of a mixture containing Pt (alloy) -supported carbon and a solid polymer film resin. That is, in this example, a hydrogen electrode (cathode) and an oxygen electrode (anode) mainly composed of a porous sheet-like carbon material are used.

  In the structure as described above, for example, when a portion where the ion conductive film and the cathode are in close contact is observed in detail, a portion where the ion conductive film and the cathode are in contact with a portion where the ion conductive film and the cathode are in contact with each other are mixed. Therefore, it is considered that an electric field imbalance occurs in the portion where the ion conductive film and the cathode are in close contact. That is, it is considered that there is a portion where the electric field concentrates locally in the ion conductive film. This concentration of electric field is thought to increase the voltage loss in the ion conductive film, lower the electric field efficiency, and further cause deterioration of the electrolysis apparatus.

  As a technique for suppressing such deterioration, a water electrolysis apparatus and a water electrolysis system are disclosed in JP 2010-059514 A (hereinafter referred to as Patent Document 2). This water electrolysis apparatus includes a solid electrolyte membrane, an anode, a cathode, and a flow path. The solid electrolyte membrane has a first surface and a second surface opposite to the first surface. The anode is provided on the first surface side in contact with the first surface and allows water to flow therethrough. The cathode is provided on the second surface side away from the second surface. The flow path is provided between the cathode and the second surface, and an electrolytic solution can be interposed therebetween.

  Patent Document 2 points out that there are at least two types of degradation mechanisms in the conventional electrolyzer as in Patent Document 1 above. The first degradation mechanism is that, among the cations moving in the ion conductive film from the anode side, cations other than hydrogen and alkali metal are deposited in the electric field concentration portion on the cathode side, and the ion conduction film The substance (mainly metal) deposited on the cathode side destroys the ion conductive film or prevents ion conduction in the ion conductive film. This deterioration occurs mainly during operation of the electrolyzer. The second mechanism of deterioration is that the hydrogen ions that are generated at the anode, move to the cathode in the ion conductive film, and should be liberated as hydrogen at the cathode are ion-conducted from the cathode when the power is shut off (power off). The catalyst activity of the anode is reduced by moving through the membrane to the anode and reacting with the anode. This deterioration mainly occurs after the operation of the electrolyzer is completed. Due to these two causes of deterioration, a phenomenon has occurred in which deterioration progresses in accordance with the operation time of the electrolyzer (first deterioration mechanism), but rapidly deteriorates due to intermittent operation (second deterioration mechanism). It was. However, the water electrolysis apparatus of Patent Document 2 and the water electrolysis system using the water electrolysis apparatus can suppress both of the two types of deterioration by having the above-described configuration.

JP 2004-353033 A JP 2010-059514 A

As in the configuration of the water electrolysis system of Patent Document 2, the cathode and the solid electrolyte membrane are separated from each other, and the space (flow path) between them is filled with the electrolytic solution, thereby improving the life of the electrode and the electrolytic efficiency. Can do. However, if the electrode life and electrolytic efficiency can be further improved, it is very useful in practice. As a result of the research, the inventor found the following degradation mechanism for the first time. That is, this is a mechanism in which an oxide (for example, PtO or PtO _{2 in} the case of platinum) is formed on the surface of the anode during electrolysis, which is largely involved in a decrease in electrolytic efficiency. As an influence on the deterioration of the oxide, it has been found that in the process of electrolysis, the oxide layer increases and the electric resistance increases, and the oxide layer formed has a low catalytic ability. Furthermore, when electrolysis is performed for a long time, oxygen further penetrates into the oxide layer on the anode surface, the oxide layer becomes porous, the electrical resistance further increases, and the contact between the anode and the electrolyte membrane is further inhibited. It was also found.

  Accordingly, an object of the present invention is to provide a water electrolysis system capable of improving the electrode life of a water electrolysis cell when water is electrolyzed. Another object of the present invention is to provide a water electrolysis system capable of suppressing a deterioration phenomenon that occurs in a water electrolysis cell, particularly in the vicinity of an anode, when water is electrolyzed. Another object of the present invention is to provide a water electrolysis system capable of improving the electrolysis efficiency of a water electrolysis cell when water is electrolyzed.

  This object and other objects and advantages of the present invention can be easily confirmed by the following description and attached drawings.

  Hereinafter, means for solving the problem will be described using the numbers and symbols used in the embodiments for carrying out the invention. These numbers and symbols are added with parentheses in order to clarify the correspondence between the description of the claims and the mode for carrying out the invention. However, these numbers and symbols should not be used for interpreting the technical scope of the invention described in the claims.

  The water electrolysis system of the present invention includes a water supply unit (90), an electrolytic solution supply unit (89), and a water electrolysis device (1). The water supply unit (90) supplies water. The electrolytic solution supply unit (89) supplies an electrolytic solution. The water electrolysis apparatus (1) is supplied with water and an electrolytic solution, performs a process of electrolyzing water, and sends out the processed water. The water electrolysis apparatus (1) includes a solid electrolyte membrane (10), an anode (4), a cathode (8), and a flow path (3c). The solid electrolyte membrane (10) has a first surface (10a) and a second surface (10b) opposite to the first surface (10a). The anode (4) is provided on the first surface (10a) side in contact with the first surface (10a), and water flows therethrough. The cathode (8) is provided on the second surface (10b) side, away from the second surface (10b). The channel (3c) is provided between the cathode (8) and the second surface (10b), and the electrolyte solution flows therethrough. The electrolytic solution contains chlorine ions. The concentration of chloride ions is 50 mg / L or more and the saturation concentration or less.

  In the above water electrolysis system, the electrolytic solution preferably has a concentration of halogen ions other than chlorine ions of 10 mg / L or less.

  In the above water electrolysis system, the residence time of water at the anode (4) is preferably greater than 0 seconds and 10 seconds or less.

  In the water electrolysis solution described above, the chlorine ions preferably include alkali metal salt or hydrochloric acid chloride ions.

  In the above water electrolysis system, the electrolytic solution preferably further contains an electrolyte material that improves electrical conductivity.

  In the above water electrolysis system, the electrolytic solution is preferably a buffer solution.

  The water electrolysis system preferably further includes a first concentration adjusting unit (102) that adjusts the chlorine ion concentration of the electrolytic solution.

  The water electrolysis system preferably further includes a second concentration adjusting unit (102) that adjusts the cation concentration of the electrolytic solution.

  In the above water electrolysis system, the electrolyte supply unit (89) preferably receives the electrolyte sent from the water electrolysis device (1) and supplies the received electrolyte to the water electrolysis device (1).

  In the water electrolysis system, the amount of the electrolyte supplied from the electrolyte supply unit (89) to the water electrolysis device (1) is the amount of water supplied from the water supply unit (90) to the water electrolysis device (1). On the other hand, it is preferably 1/1000 or more and 1/1 or less.

  The water electrolysis method of the present invention includes a step of flowing water to an anode provided in contact with a first surface of a solid electrolyte membrane and capable of flowing water, and a second surface on the second surface side of the solid electrolyte membrane. And a step of flowing an electrolytic solution between the cathode and the second surface, and a step of applying DC power between the anode and the cathode. The electrolytic solution contains chlorine ions. The concentration of chloride ions is 50 mg / L or more and the saturation concentration or less.

  In the above water electrolysis method, the electrolytic solution preferably has a halogen ion concentration other than chlorine ions of 10 mg / L or less.

  In the above water electrolysis method, the residence time of water at the anode (4) is preferably greater than 0 seconds and 10 seconds or less.

  In the above water electrolysis method, it is preferable to further comprise a step of preparing an alkali metal salt containing chlorine or an aqueous solution of hydrochloric acid as an electrolytic solution.

  According to the present invention, when water is electrolyzed, the electrode life of a water electrolysis cell can be improved. Further, according to the present invention, when water is electrolyzed, it is possible to suppress a deterioration phenomenon that occurs in a water electrolysis cell, particularly in the vicinity of the anode. In addition, according to the present invention, when water is electrolyzed, the electrolysis efficiency of a water electrolysis cell can be improved.

FIG. 1 is a block diagram showing a configuration of a water electrolysis system according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the configuration of the water electrolysis apparatus according to the embodiment of the present invention. FIG. 3A is a graph showing the relationship between the chlorine concentration in the electrolyte and the current efficiency. FIG. 3B is another graph showing the relationship between the chlorine concentration in the electrolytic solution and the current efficiency. FIG. 4 is a graph showing the relationship between current density and current efficiency. FIG. 5 is a schematic cross-sectional view showing another configuration of the water electrolysis apparatus according to the embodiment of the present invention.

  Hereinafter, a water electrolysis system according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of a water electrolysis system according to an embodiment of the present invention. The water electrolysis system 80 includes a water supply unit 90, an electrolytic solution supply unit 89, a water electrolysis apparatus 1, a control unit 88, pipes 82 to 86, valves 94 to 99, and a concentration adjustment unit 102. Arrows indicate the direction of water flow.

  In the present invention, not only water but also an electrolytic solution is supplied to the water electrolysis apparatus 1 for treating water by electrolysis to suppress the deterioration phenomenon of the electrical treatment. Details of the electrolytic solution in the water electrolysis apparatus 1, its supply method, and its role will be described later. Hereinafter, this embodiment will be described in detail.

  The water supply unit 90 removes impurities from water (eg, tap water, the same applies hereinafter) supplied via the pipe 82a and supplies the water electrolysis device 1 via the pipe 83 (and valve 95). The water supply unit 90 includes, for example, an ion exchange resin filter (not shown), and removes impurities by the ion exchange. As an impurity, it is a substance which influences the electrolysis process of the water which the cell (after-mentioned) of the water electrolysis apparatus 1 performs. Examples of such a substance include minerals such as calcium and magnesium. The ion exchange resin filter is exemplified by a cation exchange resin (salt type: exemplification, Na type). In addition to this, in order to remove chlorine, at least one of an activated carbon filter, a calcium sulfite filter, and an anion exchange resin filter may be provided. Or you may add the apparatus which removes the other substance contained in water as much as possible.

  The electrolytic solution supply unit 89 generates an electrolytic solution using water supplied via the pipe 82b and supplies the electrolytic solution to the water electrolysis apparatus 1 via the pipe 85 (and the valve 96). The electrolyte supply unit 89 generates the electrolyte by, for example, a method of adding a predetermined amount of an electrolyte material or a high concentration electrolyte stored in a tank or the like to the supplied water. Details of the electrolyte will be described later. Note that the tank or the like may be provided at another external location. Further, the portion where a predetermined amount of the high-concentration electrolytic solution is added may be other than the electrolytic solution supply unit 89. For example, in the water electrolysis apparatus 1, it is supplied between the cathode and the ion conductive film (described later). Also good.

  When the electrolytic solution used in the water electrolysis apparatus 1 is reused, the concentration adjusting unit 102 adjusts the ion concentration of the used electrolytic solution and supplies the adjusted electrolytic solution to the electrolytic solution supply unit 89. Accordingly, the electrolytic solution is circulated using the circulation path of the electrolytic solution supply unit 89-piping 85 (valve 96)-water electrolysis apparatus 1-piping 86 (valve 98)-concentration adjusting unit 102-electrolytic solution supply unit 89. Can be reused. The concentration adjusting unit 102 adjusts the chlorine ion concentration, the hydrogen ion concentration, the cation concentration, and the like. For example, an anion exchange resin in which a specific anion such as chlorine ion is adsorbed or a cation exchange resin in which a specific cation such as hydrogen ion or sodium ion is adsorbed is provided. Thereby, the composition change of electrolyte solution can be relieved and the replacement frequency of electrolyte solution can be reduced.

  When the electrolytic solution is circulated and used, the amount of the electrolytic solution that the electrolytic solution supply unit 89 supplies to the water electrolysis device 1 is 1/1000 of the amount of water that the water supply unit 90 supplies to the water electrolysis device 1. The above is preferable. There is no particular upper limit, but it is, for example, 1/1 or less in terms of cost. For example, when the amount of electrolyzed water delivered from the anode side of the water electrolysis apparatus 1 is 1000 L, the electrolyte solution on the cathode side is 1 L or more. That is, it is preferable to prepare and use 1 L or more of a fresh electrolyte solution of the same quality (example: same ion concentration). This is because, as will be described later, in order to increase the electrolytic efficiency, it is necessary to keep the chlorine ion concentration of the electrolytic solution within a predetermined range.

  In the water electrolysis apparatus 1, water is supplied from the water supply unit 90 to the anode side via the pipe 83, and the electrolyte solution is supplied from the electrolyte solution supply part 89 to the cathode side via the pipe 85. And the electrical process (electrolysis) which applies electric power to water is performed. Water molecules are decomposed by this electrolysis. Thereby, a product corresponding to the magnitude of the electric power applied to the water is generated. For example, when electric power (voltage, current) used in normal electrolysis is used, oxygen gas is generated on the anode side and hydrogen gas is generated on the cathode side. On the other hand, if higher power (high voltage, current) than that used in normal electrolysis is used, radical oxygen water rich in radical molecules is generated on the anode side. Radical molecules are exemplified by active oxygen, hydrogen peroxide, ozone, and hydroxyl radicals. Further, hydrogen gas or hydrogen radicals are generated on the cathode side. The water electrolysis apparatus 1 discharges water containing the anode side product to the pipe 84 and discharges the electrolyte containing the cathode side product to the pipe 86.

  The pipe 81 supplies water (for example, tap water). The valve 91 is provided in the middle of the pipe 81 and controls the flow of water in the pipe 81. The valve 92 and the valve 93 are provided in the middle of the pipe 81 and control the flow of water that bypasses the water electrolysis system 80. The pipe 82 branches from the pipe 81 between the valve 91 and the valve 92 and is connected to the valve 94. The valve 94 controls the supply of water to the water electrolysis system 80. The pipe 82 a connects between the valve 94 and the water supply unit 90. The pipe 82 b connects between the valve 94 and the electrolyte supply unit 89. The pipe 83 connects the water supply unit 90 and the water electrolysis apparatus 1 (anode side) via a valve 95. The pipe 85 connects the electrolytic solution supply unit 89 and the water electrolysis apparatus 1 (cathode side) via a valve 96. The pipe 84 is connected to the water electrolysis apparatus 1 (anode side), can drain water (on the anode side) through the valve 97, and drains water to the pipe 81 through the valve 99 and the check valve. Is possible. The pipe 86 is connected to the water electrolysis apparatus 1 (cathode side), can discharge the electrolyte solution (cathode side) through the valve 100, and circulates the electrolyte solution to the concentration adjusting unit 102 through the valve 98. Is possible.

  The control unit 88 controls the operations of the valves 91 to 100, the water supply unit 90, the electrolytic solution supply unit 89, the concentration adjustment unit 102, and the water electrolysis apparatus 1. However, it is not necessary to control all by the control part 88, and you may control by several control apparatuses. Moreover, it is also possible to control everything manually without providing the control unit 88. The controller 88 is exemplified by a personal computer or a microcomputer.

  The water electrolysis apparatus 1 will be further described. FIG. 2 is a schematic cross-sectional view showing the configuration of the water electrolysis apparatus according to the embodiment of the present invention. The water electrolysis apparatus 1 includes a power supply unit 1b and a water electrolysis apparatus body 1a. The operation of the power supply unit 1b is controlled by the control unit 88. Arrows indicate the direction in which water, electrolyte, etc. flow. Here, the water electrolysis apparatus which performs the electrolysis which produces | generates radical oxygen water instead of normal electrolysis is demonstrated. However, if the applied power is changed to a low level, a normal electrolysis water electrolysis apparatus is obtained.

The power supply unit 1b supplies power to the water electrolysis apparatus main body 1a. The power supply unit 1 b includes an AC power supply 32 and a conversion unit 31. The AC power supply 32 supplies predetermined AC power. The AC power source 32 is exemplified by a system power source (a power source supplied from a commercial distribution line owned by an electric power company, for example, 100 V or 200 V). The converter 31 is supplied with AC power from the AC power supply 32 and converts it into predetermined DC power. And the direct-current power is supplied to the water electrolysis apparatus main body 1a. The supplied DC power is, for example, a voltage of 4 to 20 V and a current per unit area of the cell of the water electrolysis device main body 1 a: 0.1 to 5 A / cm ² . Since this voltage and current are larger than the direct current power of electrolysis of water, ozone and active oxygen are likely to be generated by the reaction at the anode. Therefore, in this case, the water electrolysis apparatus 1 generates radical oxygen water.

  In the water electrolysis apparatus main body 1a, the water 21 processed by the water supply unit 90 is supplied to the anode side, and the electrolyte solution 23 processed by the electrolyte solution supply unit 89 is supplied to the cathode side. Then, the water 21 is electrically processed (electrolyzed) with the power supplied from the power supply unit 1b, and is sent to the outside as radical oxygen water 22. The electrolytic solution 23 is circulated and reused. The water electrolysis apparatus main body 1 a includes an anode side channel 2, a cathode side channel 3, and a cell 13. The cell 13 includes an ion conductive film 10, an anode part 11, and a cathode part 12.

  The anode side flow path 2 has an opening 2a, flow paths 2b, 2c, 2d, and an opening 2e. The opening 2 a is provided on the outer surface of the water electrolysis apparatus main body 1 a and is connected to the pipe 83. The water 21 treated by the water supply unit 90 is introduced into the water electrolysis apparatus main body 1a. The channel 2b is provided from the opening 2a toward the end of the anode portion 11 inside the water electrolysis apparatus main body 1a. Water 21 supplied through the opening 2a is supplied to the anode unit 11. The flow path 2c is a gap portion inside the anode 4 of the anode portion 11 and the Ti wire net 5 (described later). That is, the supplied water 21 circulates through the gaps inside the anode 4 and the Ti wire net 5 as the flow path 2c. However, the portion in contact with the anode 4 and the ion conductive film 10 and the portion not in contact are mixed. The flow path 2d is provided from the end of the anode part 11 toward the outer surface of the water electrolysis apparatus main body 1a. The radical oxygen water 22 processed by the anode part 11 is sent out to the opening part 2e. The opening 2 e is provided on the outer surface of the water electrolysis apparatus main body 1 a and is connected to the pipe 84. Water 22 from the flow path 2d is sent out from the water electrolysis apparatus main body 1a.

  The cathode side flow path 3 has an opening 3a, flow paths 3b, 3c, 3d, and an opening 3e. The opening 3 a is provided on the outer surface of the water electrolysis apparatus main body 1 a and is connected to the pipe 85. The electrolytic solution 23 processed by the electrolytic solution supply unit 89 is introduced into the water electrolysis apparatus main body 1a. The flow path 3b is provided from the opening 3a toward the end of the cathode part 12 inside the water electrolysis apparatus main body 1a. The electrolyte solution 23 supplied through the opening 3 a is supplied to the cathode unit 12. The flow path 3c is a gap (partly including a gap inside the cathode 8) provided between the cathode 8 of the cathode portion 12 and the ion conductive film 10 (described later). In other words, the supplied electrolytic solution 23 flows through the gap between the cathode 8 serving as the flow path 3 c and the ion conductive film 10. However, the cathode 8 and the ion conductive film 10 are not in contact with each other and are not in contact with each other. The flow path 3d is provided from the end portion of the cathode portion 12 toward the outer surface of the water electrolysis device main body 1a. The electrolyte solution 24 that has passed through the flow path 3c is delivered to the opening 3e. The opening 3 e is provided on the outer surface of the water electrolysis apparatus main body 1 a and is connected to the pipe 86. The electrolytic solution 24 from the flow path 3d is sent out from the water electrolysis apparatus main body 1a.

  The cell 13 is provided in the water electrolysis apparatus main body 1 a and includes an ion conductive film 10, an anode part 11, and a cathode part 12. Water 21 supplied from the water supply section 90 is supplied to the anode section 11 via the anode-side flow path 2, and electrolyte solution 23 supplied from the electrolyte supply section 89 is supplied to the cathode section 12 via the cathode-side flow path 3. Supplied respectively. The cell 13 generates radical oxygen water 22 by electrically treating the water 21 in the anode portion 12 with direct current power supplied from the power source portion 1 b to the anode portion 11 and the cathode portion 12.

  The ion conductive film (solid electrolyte membrane) 10 is a proton conductive film (H-type ion exchange membrane) having a first surface 10a on the anode side and a second surface 10b on the cathode side. Examples of the proton conductive film include solid polymer membrane sulfonic acid type strongly acidic cation exchange resins and perfluorosulfonic acid polymer membranes. For example, a Nafion membrane (registered trademark: manufactured by DuPont) is exemplified. The film thickness is, for example, 0.2 mm.

  The anode part 11 is provided so as to be in contact with one surface 10a of the ion conductive film 10 and water 21 can flow therethrough. The anode part 11 functions as an electrode to which DC power is supplied from the power supply part 1b. The anode part 11 includes a first electrode part 6, a second electrode part 5, and an anode 4. The first electrode unit 6 is connected to the positive electrode of the conversion unit 31 when the conversion unit 31 supplies DC power to the cell 13. The first electrode unit 6 is a conductive plate, and is exemplified by a Ti (titanium) plate. The second electrode portion 5 is provided so that one surface is in close contact with the first electrode portion 6 and the other surface is in close contact with the anode 4. The 2nd electrode part 5 is a conductive porous body or net | network which can permeate | transmit water 21, and is illustrated by Ti (titanium) metal net. The wire mesh is, for example, 0.4 to 0.6 mmφ and 40 mesh. The anode 4 is provided so that one surface is in close contact with the second electrode portion 5 and the other surface is in close contact with one surface 10 a of the ion conductive film 10. The anode 4 is a porous body or net that is permeable to water 21 and has a catalytic function for electrolytic reaction, and is exemplified by a Pt (platinum) metal net. The wire mesh is, for example, 0.05 to 0.1 mmφ and 80 mesh.

  The cathode portion 12 is provided apart from (not in contact with) the other surface 10 b of the ion conductive film 10. The supplied electrolytic solution 23 can flow through the flow path 3 c that is between the cathode portion 12 and the ion conductive film 10 (gap). The cathode portion 12 includes an electrode portion 9 and a cathode 8. The electrode unit 9 is connected to the negative electrode of the conversion unit 31 when the conversion unit 31 supplies DC power to the cell 13. The electrode unit 9 is a conductive plate and is exemplified by a Ti (titanium) plate. The cathode 8 is provided such that one surface thereof is in close contact with the electrode portion 9 and the other surface is separated from the other surface 10 b of the ion conductive film 10. The supplied electrolytic solution 23 can flow through the flow path 3 c that is between the cathode 8 and the ion conductive film 10 (gap). The cathode 8 is a porous body or net that is permeable to the electrolytic solution 23 and has a catalytic function for electrolytic reaction, and is exemplified by a Pt (platinum) metal net. The wire mesh is, for example, 0.05 to 0.1 mmφ and 80 mesh.

  When a wire mesh (example: Ti wire mesh) is used as the second electrode portion 5 and a wire mesh (example: Pt wire mesh) is used as the anode 4, the Ti wire mesh and the Pt wire mesh overlap each other (hereinafter referred to as "micro flow path"). Also called). Therefore, when the supplied water 21 passes at high speed through the wire mesh that is the contact portion between the second electrode portion 5 and the anode 4 and the ion conductive film 10, the flow is disturbed.

  On the other hand, when a wire mesh (example: Pt wire mesh) is used as the cathode 8, the Pt wire mesh forms a narrow channel. Therefore, the supplied electrolytic solution 23 is in a state where it is filled in the wire mesh and in the gap (flow path 3 c) between the ion conductive film 10 and the cathode 8.

  In such a state of the anode part 11 and the cathode part 12, ozone or the like (bubbles) is generated on the anode side by electrolysis caused by supplying electric power between the anode part 11 and the cathode part 12. In that case, the bubbles generated by electrolysis pass through the microchannel at high speed together with the water flow whose flow is disturbed. For this reason, it is considered that the bubbles have a very fine size that is equal to or smaller than the width of the microchannel, and the gas-liquid contact area increases. As a result, the bubbles can be efficiently dissolved in water. That is, the supplied water 21 is efficiently electrolyzed when passing through the vicinity of the anode 4 and is sent out as radical oxygen water 22 in which ozone and oxygen are dissolved. Thereby, the concentration of ozone or the like of the radical oxygen water 22 generated in the water electrolysis apparatus 1 can be increased.

  As the electrolytic solution 23, a solution containing chlorine ions is always used. For example, when water is used as a solvent, an aqueous solution in which an alkali metal salt containing chlorine is dissolved, or hydrochloric acid diluted with water. Examples of the alkali metal salt containing chlorine include sodium chloride, potassium chloride, and lithium chloride. It is also effective to use other chlorides dissolved in some solvent. Details of the electrolytic solution 23 will be described later.

  As the distance d between the cathode 8 and the ion conductive film 10 is larger, the deterioration of the ion conductive film 10 is reduced. However, if it is too large, the power loss increases due to the limit of the conductivity of the electrolytic solution 23. Therefore, the lower limit is preferably a distance at which a potential difference that is at least 1/10 of the potential difference ΔV generated between the cathode side and the anode side of the ion conductive film 10 is preferable in consideration of effects such as prevention of deterioration. On the other hand, the upper limit is preferably a distance at which a potential difference that is four times the potential difference ΔV occurs in consideration of the limit of the conductivity of the electrolytic solution.

  For example, when a sodium chloride aqueous solution is used as the electrolytic solution, the distance d between the cathode 8 and the ion conductive membrane 10 is as follows. If the electrolytic solution 23 is a 10% by weight sodium chloride aqueous solution, its conductivity is 121 mS / cm. This value is substantially equal to the conductivity of the ion conductive film 10 such as Nafion, for example. Therefore, when the electrolytic solution 23 having such a concentration is used, the distance d between the ion conductive film 10 and the cathode 8 can be 0.1 to 4 times the film thickness of the ion conductive film 10. That is, if the film thickness of the ion conductive film 10 is 0.2 mm, the distance d between the ion conductive film 10 and the cathode 8 is 0.02 mm to 0.8 mm.

  As a method for providing a gap (flow path 3c) between the cathode 8 and the ion conductive film 10, for example, the anode part 11 and the ion conductive film 10 are integrally held in the casing of the water electrolysis apparatus main body 1a. It is conceivable that the cathode 12 is separated from the ion conductive membrane 10 and held in the casing of the water electrolysis apparatus main body 1a. Further, between the cathode 8 and the ion conductive film 10, for example, by applying a higher pressure to the electrolyte solution 23 on the cathode side than the water 21 on the anode side, the adhesion between the ion conductive film 10 and the anode 4 is ensured. In addition, the distance d between the ion conductive film 10 and the cathode 8 can be kept constant.

Next, the electrolytic solution 23 will be described in detail.
As described above, the inventor has found for the first time that an oxide (for example, PtO or PtO _{2 in} the case of platinum) formed on the surface of the anode during electrolysis greatly contributes to a decrease in electrolytic efficiency. That is, the increase in the oxide layer in the process of electrolysis causes an increase in the electrical resistance of the anode. In addition, an increase in the number of oxide layers having a low catalytic ability leads to a decrease in reaction efficiency at the anode. Furthermore, in the case of electrolysis for a long time, the oxide layer becomes porous, the electric resistance of the oxide layer itself further increases, the contact between the anode and the electrolyte membrane is inhibited, and the contact resistance increases.

  The inventor found for the first time that the formation of an oxide layer on the surface of the anode can be remarkably suppressed by dissolving chlorine ions in the electrolyte solution on the cathode side at a certain concentration or more. The suppression of the formation of the oxide layer is considered to be due to the following mechanism. That is, when chlorine ions of a certain concentration or more are dissolved in the electrolytic solution, the chlorine ions pass through the electrolyte membrane (ion conductive film 10) and reach the anode side, and the anode 4 and the electrolyte membrane (ion conductive film 10). ) Will be concentrated on the interface. Oxidation on the anode surface is inhibited by the chlorine ions, and the anode surface is kept in a fresh state. As a result, the electrolytic efficiency and the electrode life can be improved. This effect is expected to be stronger as the concentration of chlorine ions in the electrolyte is higher.

Next, the results of experiments conducted on the relationship between the concentration of chlorine ions in the electrolytic solution and the electrolytic efficiency will be described. FIG. 3A is a graph showing the relationship between the chlorine concentration in the electrolyte and the current efficiency. The horizontal axis indicates the chlorine (Cl) concentration (mg / L) contained in the electrolytic solution 23. That is, the chlorine concentration in the electrolytic solution in which NaCl is dissolved using water as the solvent is shown. In this case, the chlorine concentration is equal to or lower than the saturation concentration, and can be regarded substantially as a chlorine ion (Cl ⁻ ) concentration. On the other hand, the vertical axis represents the current efficiency (%) calculated based on the amount of ozone generated at the anode. That is, the ratio of the current used for ozone generation to the supplied current is shown. In this case, the current efficiency (%) can be regarded as one index of the electrolytic efficiency (electrolytic efficiency). Triangles (curve I), squares (curve II), and diamonds (curve III) have current densities of 1 A / cm ² , 0.75 A / cm ² , and 0.5 A / cm, respectively, supplied to the cell 13. The case of ² is shown. This experiment was performed using the water electrolysis system 80 described in FIG. 1 and FIG.

Referring to FIG. 3A, when the chlorine concentration is regarded as the chlorine ion (Cl ⁻ ) concentration, it can be seen that the current efficiency monotonously increases with respect to the chlorine ion concentration regardless of the current density. If the chlorine ion concentration is 50 mg / L (0.0014 mol / L: P in FIG. 3A) or higher than the case where the chlorine ion concentration is 35.5 mg / L (0.001 mol / L), It was found that the current efficiency was improved and a sufficient effect was obtained. Further, the chlorine ion concentration is preferably 100 mg / L (0.0028 mol / L) or more. Furthermore, the chlorine ion concentration is more preferably 177.5 mg / L (0.005 mol / L) or more. On the other hand, the higher the chlorine ion concentration, the better. However, in the case of an electrolytic solution in which NaCl is dissolved using water as a solvent, it is determined by the saturated concentration (solubility) of NaCl. In that case, for example, it is about 218 g / L at room temperature (example: 30 ° C.).

  Further, it has been found that if the chlorine ion concentration is sufficiently high, 17,750 mg / L (0.5 mol / L) or more, the effect of approximately 28% current efficiency can be obtained regardless of the current density. Therefore, when a current efficiency of about 28% is sufficient, a concentration in the vicinity thereof, for example, 17.750 g / L (0.5 mol / L) to 71.000 g / L (2.0 mol / L), It is considered possible to obtain a certain effect.

The reason that the antioxidant effect by chlorine ions occurs is considered to be that Cl ⁻ ions are coated on the anode surface in a wide potential range. The Cl ⁻ ion coating prevents oxygen from reaching the anode surface and consequently prevents the formation of an oxide layer on the surface. Even if an oxide layer is formed on the anode surface, in the presence of Cl ⁻ ions, the oxide layer changes into chloride (eg, PtCl ₄ ) and elutes in water. It was also found that there was little accumulation.

Further, from the inventors' experiments, it has been found that the electrolytic solution 23 preferably contains as little halogen ions (eg, F ⁻ , Br ⁻ , I ⁻ ) as chlorine ions. This is because chlorine ions have the above effects, and other halogen ions do not have the effects and may inhibit the effects of chlorine ions. Specifically, the halogen ion is preferably 10 mg / L or less (for example, F ⁻ , Br ⁻ , I ⁻ = 0.53, 0.13, 0.08 × 10 ⁻³ mol / L) or less. Furthermore, it is more preferable to set it to 1 mg / L (example: 0.053, 0.013, 0.008 * 10 < ^-3 > mol / L) or less.

The effect of these chlorine ions is more remarkable when the chlorine ions are present in the electrolytic solution supplied to the cathode than when the chlorine ions are present in the water supplied to the anode. According to the inventor's experiment, for example, an aqueous solution of NaCl: 0.001 mol / L was used on the anode side, and the amount of ozone generated at the anode at a current density of 0.5 A / cm ² was about 0.55 mg / L. In contrast, the amount of ozone generated at the anode when the NaCl: 0.001 mol / L aqueous solution was used on the cathode side and the current density was 0.5 A / cm ² was about 7.9 mg / L. That is, it has been found that mixing chlorine ions on the cathode side has an effect 10 times or more. This is because Cl ⁻ ions in the electrolyte solution on the cathode side migrate in the electrolyte membrane due to a potential difference and are concentratedly supplied to the surface of the anode, but even if Cl ⁻ ions exist in the water on the anode side, This is because the action like the Cl ⁻ ion on the side hardly appears. Therefore, it is very important that chlorine ions are present in the cathode solution.

Here, if Cl ⁻ ions concentrate on the anode surface, hypochlorite ions may be generated in the product. However, the reaction generation rate of hypochlorous acid by electrolysis is slow. Therefore, by increasing the flow rate of water in the anode portion 11 in the cell 13 of the water electrolysis apparatus 1 having the structure shown in FIGS. 1 and 2, water is discharged out of the cell 13 before hypochlorous acid is generated. can do. Increasing the water flow rate corresponds to shortening the time during which water stays in the cell 13. Therefore, it can be seen that the shorter the residence time, the less hypochlorous acid is produced, which is preferable. The preferable range of the residence time varies depending on the apparatus used and the use conditions. According to the research by the inventors, under normal use conditions (example: applied voltage: 4 to 20 V, current density: 0.1 to 5 A / cm ² , chloride ion concentration of electrolyte: 50 mg / L to 218 g / L) If the residence time of water in the cell 13 is 10 seconds or less, generation of hypochlorite ions can be suppressed, and if the residence time of water in the cell 13 is 1 second or less, generation of hypochlorite ions It was found that can be greatly suppressed. The reason is as follows.

  The rate of formation of hypochlorous acid by electrolysis is proportional to the current density. And 40 mg / Ah hypochlorite ion is produced | generated by the current density on the normal use conditions of the said cell 13. FIG. When this is applied to the cell 13, the amount of hypochlorous acid produced is estimated to be about 1 mg by setting the residence time of about 10 seconds at the current density of the normal use condition of the cell 13. This is a hypochlorous acid concentration of about 1 mg / L, which is significantly lower than the concentration of ozone produced. That is, the concentration of hypochlorous acid is not as effective as that of ozone. However, since generation of hypochlorous acid cannot be ignored when the residence time becomes long, the residence time of the electrolyzed water flowing in the cell 13 is more preferably 1 second or less. Furthermore, it is preferable to set it as 0.5 second or less, and it is still more preferable to set it as 0.1 second or less.

  Further, by increasing the flow rate of water in the anode part 11 and shortening the residence time of the water in the anode part 11, the ionic species and bubbles generated on the anode part 11 side are quickly flowed out and are fresh. Water can be supplied. As a result, the generation efficiency of the radical oxygen water 22 in the water electrolysis apparatus 1 can be increased.

  In addition, another electrolyte material may be added to the electrolytic solution 23 in order to improve electric conductivity. For example, a material that generates nitrate ions or sulfate ions. Examples of such materials include nitric acid, sulfuric acid, sodium nitrate, or sodium sulfate.

  Furthermore, in order to stabilize the pH of the electrolytic solution 23, the electrolytic solution 23 may be a buffer solution. For example, by adding boric acid + sodium borate, phosphoric acid + sodium phosphate, acetic acid + sodium acetate, or citric acid + sodium citrate to an aqueous solution of NaCl, the electrolytic solution 23 can be used as a buffer solution. .

Next, the results of another experiment conducted on the relationship between the concentration of chlorine ions in the electrolytic solution and the electrolytic efficiency will be described. In this experiment, the effect of performing electrolysis for a long time is examined. FIG. 3B is a graph showing the relationship between the chlorine concentration in the electrolytic solution and the current efficiency. Also in this case, the horizontal axis indicates the chlorine (Cl) concentration (mg / L) contained in the electrolytic solution 23. That is, the chlorine concentration in the electrolytic solution in which NaCl is dissolved using water as the solvent is shown. In this case, the chlorine concentration is equal to or lower than the saturation concentration, and can be regarded substantially as a chlorine ion (Cl ⁻ ) concentration. The vertical axis shows the current efficiency (%) calculated based on the amount of ozone generated at the anode. That is, the ratio of the current used for ozone generation to the supplied current is shown. In this case, the current efficiency (%) can be regarded as one index of the electrolytic efficiency (electrolytic efficiency). The rhombus (curve α) indicates the current efficiency within 1 hour (initial state) after the start of electrolysis, and the circle (curve β) indicates the current efficiency after 20 hours of continuous operation after the start of electrolysis. However, the current density is 0.625 A / cm ² in all cases. This experiment was performed using the water electrolysis system 80 described in FIG. 1 and FIG.

Referring to FIG. 3B, assuming that the chlorine concentration is the chlorine ion (Cl ⁻ ) concentration, the current efficiency in the initial state is greatly reduced when the chlorine ion concentration becomes 100 mg / L or less, but the current efficiency after 20 hours of operation is Furthermore, the decrease is great. Practically, since the current efficiency is preferably 10% or more, a chlorine ion concentration of at least 50 mg / L (0.0014 mol / L: Q in FIG. 3B) or more is required for a long-time operation. I understand that.

  As described above, when the chlorine ion concentration in the electrolytic solution 23 is low, an oxide film is generated on the surface of the anode, thereby inhibiting the generation of ozone and lowering the current efficiency. However, when the chlorine ion concentration in the electrolytic solution 23 is sufficiently high, the oxide on the anode surface is dissolved by chlorine, so that the formation of an oxide film on the anode surface can be suppressed. And it turns out that the effect becomes so remarkable that the time of electrolysis becomes long. Also from this data, it is understood that the chloride ion concentration of the electrolytic solution 23 is at least 50 mg / L, and preferably 100 mg / L or more.

Next, the experimental results of the relationship between the current density flowing through the cell and the electrolytic efficiency will be described. FIG. 4 is a graph showing the relationship between current density and current efficiency. The horizontal axis indicates the current density (A / cm ² ) of the current flowing through the cell 13. On the other hand, the vertical axis represents the current efficiency (%) calculated based on the amount of ozone generated at the anode. In this case, the current efficiency (%) can be regarded as one index of the electrolytic efficiency. In the rhombus (curve A), the square (curve B), and the triangle (curve C), the chlorine ion concentration (chlorine concentration) of the electrolytic solution 23 supplied to the cathode 8 is 0.5 mol / L and 0.01 mol / L, respectively. , And 0.005 mol / L. This experiment was performed using the water electrolysis system 80 described in FIG. 1 and FIG.

Referring to FIG. 4, it was found that the current efficiency increases as the current density increases, but the current efficiency is saturated when the current density reaches a certain value. For example, in the case of 0.5 mol / L (curve A), it can be seen that when the current is 0.5 A / cm ² or more, the current efficiency is approximately saturated at about 28%. Even in the case of 0.01 mol / L (curve B) and 0.005 mol / L (curve C), the graph is not completely saturated, but it can be seen that it is saturated by increasing the current density. It can also be seen that the higher the chlorine ion concentration (chlorine concentration), the more saturated the current efficiency at a lower current density. Therefore, it is supported that a sufficient current efficiency can be obtained at a low current density by increasing the chlorine ion concentration.

When the results of FIGS. 3A, 3B, and 4 are summarized, the chlorine ion (Cl ⁻ ) concentration is 50 mg / L (0.0014 mol / L: P in FIG. 3A, Q in FIG. 3B) or more. The current efficiency is improved and a sufficient effect is obtained. In addition, if the chlorine ion concentration is sufficiently high and 17750 mg / L (0.5 mol / L) or more, the effect of current efficiency of 28% or more can be obtained regardless of the current density. There is no particular upper limit on the chlorine ion concentration, and a saturated concentration may be used. However, if a current efficiency of about 28% is sufficient, the concentration in this vicinity, for example, 17.750 g / L (0.5 mol / L) to 71.000 g / L (2.0 mol / L) may be used. Good. Moreover, when trying to obtain sufficient current efficiency at a lower current density, it can be achieved by increasing the chlorine ion concentration.

Next, technical effects of the water electrolysis apparatus according to the present embodiment will be described.
In the present embodiment, chlorine ions are dissolved in the electrolyte solution 23 on the cathode side at a certain concentration (50 mg / L) or more. Thereby, formation of the oxide layer on the surface of the anode 4 can be remarkably suppressed. That is, when chlorine ions of a certain concentration or more are dissolved in the electrolytic solution 23, chlorine ions move through the ion conductive film 10 and move to the anode side, and chlorine is transferred to the interface between the anode 4 and the ion conductive film 10. The ions will be concentrated. As a result, the oxidation on the anode surface is inhibited by the chlorine ions, or the oxide layer is chlorinated and removed. Therefore, the anode surface can be kept in a fresh state. As a result, the electrolytic efficiency and the electrode life can be improved.

  In the present embodiment, the cathode 8 is separated from the ion conductive film 10, and the flow path 3c therebetween is filled with the electrolytic solution 23. In such a structure, the electric field concentration in the ion conductive film 10 is relaxed, and the electric field becomes almost uniform. The density of ions moving in the ion conductive film 10 becomes substantially uniform, and the voltage loss in the ion conductive film 10 can be minimized. Further, when the power is shut off (power is turned off), hydrogen ions in the vicinity of the cathode 8 are trapped by anions in the electrolytic solution 23. Therefore, the hydrogen ions do not move into the ion conductive film 10. In addition, hydrogen ions in the ion conductive film 10 are also trapped by anions in the ion conductive film 10. Therefore, hydrogen ions that move to the anode side are very few. Therefore, since the reaction of the anode 4 with hydrogen is greatly suppressed, the catalytic activity of the anode 4 is maintained even when the power supply is shut off.

  Due to the above effects, the deterioration of the anode 4 and the ion conductive film 10 can be minimized, and the electrode life and the electric field efficiency can be improved. As a result, the life and efficiency of the water electrolysis system is greatly improved.

  Next, the operation of the water electrolysis system according to the embodiment of the present invention will be described. Here, a water electrolysis system that performs electrolysis to generate radical oxygen water instead of normal electrolysis will be described. However, if the applied power is changed to a low level, a normal electrolysis water electrolysis system is obtained.

  Referring to FIG. 1, valves 91, 93, 94, 95, 96, 98, 99 are open. The valve 92 is opened to such an opening that allows a quantity of water necessary for mixing water and radical oxygen water to be mixed in a desired ratio to the pipe 82.

  The tap water flowing through the pipes 82 and 82 a is supplied to the water supply unit 90. The water supply unit 90 removes substances that affect the electrical treatment of water performed by the cell 13 of the water electrolysis apparatus 1 from the tap water. The water 21 treated by the water supply unit 90 is supplied to the anode side of the water electrolysis apparatus 1 through the pipe 83. On the other hand, tap water flowing through the pipes 82 and 82 b is supplied to the electrolyte supply unit 89. The electrolytic solution supply unit 89 generates the electrolytic solution 23 using tap water. The electrolytic solution 23 generated by the electrolytic solution supply unit 89 is supplied to the cathode side of the water electrolysis apparatus 1 through the pipe 85. The electrolytic solution 23 has a chlorine ion concentration of 50 mg / L or more and other halogen ion concentrations of 10 mg / L or less.

  With reference to FIG. 2, the water 21 treated by the water supply unit 90 flows through the flow path 2 b of the water electrolysis apparatus 1 and is supplied to the anode unit 11. The water 21 flows through the second electrode unit 5 and the anode 4. On the other hand, the electrolytic solution 23 generated in the electrolytic solution supply unit 89 flows through the flow path 3 b of the water electrolysis apparatus 1 and is supplied to the cathode unit 12. The electrolytic solution 23 flows through the cathode 8 and the flow path 3c. The conversion unit 31 of the power supply unit 1 b supplies a predetermined DC voltage between the anode unit 11 and the cathode unit 12. As a result, an electrolytic reaction is performed among the cathode 8, the ion conductive film 10, and the anode 4. The electrolytic reaction produces more ozone and active oxygen than oxygen gas on the anode side. As a result, radical oxygen water 22 rich in radical molecules such as active oxygen, hydrogen peroxide, ozone, and hydroxyl radicals is generated on the anode side. The radical oxygen water 22 is sent to the outside (pipe 84) of the water electrolysis apparatus 1 through the flow path 2d. On the cathode side, hydrogen is generated in the electrolyte. At this time, the flow rate of water on the anode side is controlled so that the residence time is 1 second or less. When 1000 L of radical oxygen water 22 is generated, at least 1 L of the electrolyte solution 23 is used. For example, while 1000 L of water is supplied to the anode 4, at least 1 L of the electrolyte solution 23 that is not reused is supplied to the cathode 8.

A small part of the chlorine ions in the electrolytic solution 23 passes through the electrolyte membrane, and the chloride ions move to the interface between the anode and the electrolyte membrane. As a result, the anode surface is covered with chlorine ions, and the formation of an oxide film is prevented. Even if an oxide layer is formed on the anode surface, in the presence of chlorine ions, the oxide layer changes to chloride (eg, PtCl ₄ ) and elutes in water, so that the oxide layer is accumulated on the anode surface. There is little to do. Further, since the cathode 8 is separated from the ion conductive film 10 and the flow path 3c therebetween is filled with the electrolytic solution 23, the electric field concentration in the ion conductive film 10 is relaxed, and the electric field becomes almost uniform. The density of ions moving in the ion conductive film 10 becomes substantially uniform, and the voltage loss in the ion conductive film 10 can be minimized.

  Referring to FIG. 1, radical oxygen water 22 is mixed with water in pipe 81 bypassing water supply unit 90 and water electrolysis device 1 via pipe 84 and valve 99. And it sends out from the valve | bulb 93 as the radical oxygen water 22 which has a desired density | concentration. The radical oxygen water 22 can be used as it is through the valve 97 without being mixed with the water in the pipe 81. On the other hand, the waste electrolyte solution 24 used in the cathode unit 12 of the water electrolysis apparatus 1 is supplied to the concentration adjusting unit 102 via the pipe 86, and after being adjusted in concentration, is circulated and reused to the electrolyte solution supplying unit 89. Is done. However, it may be discharged to the outside through the valve 100.

  Thereafter, when the power of the water electrolysis apparatus 1 is shut off (power off), the hydrogen ions in the vicinity of the cathode 8 become anions in the electrolytic solution 23, and the hydrogen ions in the ion conductive film 10 also become anions in the ion conductive film 10. Each is trapped. Therefore, the hydrogen ions hardly move. Since the reaction of the anode 4 with hydrogen ions is greatly suppressed, the catalytic activity of the anode 4 is maintained even when the power supply is shut off.

  As described above, the water electrolysis system according to the embodiment of the present invention can operate.

  In the above embodiment, only the electrolytic solution 23 exists between the cathode 8 and the ion conductive film 10. However, the present invention is not limited to the examples. That is, a nonconductive member containing the electrolytic solution 23 may be provided between the cathode 8 and the ion conductive film 10. FIG. 5 is a schematic cross-sectional view showing another configuration of the water electrolysis apparatus according to the embodiment of the present invention. This water electrolysis apparatus 1 is basically the same as the water electrolysis apparatus 1 of FIG. However, it differs from the case of FIG. 2 in that the non-conductive member 7 is provided between the cathode 8 and the ion conductive film 10 (flow path 3c).

  The nonconductive member 7 is provided between the cathode 8 and the ion conductive film 10 (flow path 3c), and is formed of a nonconductive material. The nonconductive member 7 can circulate the electrolytic solution 23 therein, and is exemplified by a porous body or a net-like body. As the non-conductive member 7, for example, a sponge-like member using an inorganic material such as glass fiber or quartz fiber or an organic material such as sponge or cotton can be used. In particular, inorganic materials such as glass fibers and quartz fibers are preferable because they are more stable and effective in liquids than organic materials. The non-conductive member 7 is preferably elastic. In that case, the non-conductive member 7 having elastic force is sandwiched between the ion conductive film 10 and the cathode 8 instead of applying a higher pressure to the cathode-side electrolyte solution 23 than the anode-side water 21. It is possible to adopt a structure in which the ion conductive film 10 is pressed against the anode 4 by the elastic force of the nonconductive member 7.

  Further, the electrolyte solution 23 may exist in a state where it is contained in a sponge or cotton as the nonconductive member 7, or a tank storing the electrolyte solution 23 may be provided outside and circulated by a pump. By doing so, the composition change of the electrolytic solution 23 is reduced, and the replenishment and replacement of the electrolytic solution 23 are facilitated.

In the present embodiment, the radical oxygen water generated using tap water which is the raw material water contains a radical amount that is not found in the prior art, for example, about 10 ¹⁷ / L or more. is there. Therefore, even if about 20% to 30% is added to tap water which is raw material water, the effect (example: sterilization effect) can be confirmed. In conventional electrolyzed water, a technique for diluting and applying electrolyzed water, such as dilution application, has not been confirmed due to its character. However, in the radical oxygen water of the present invention, a use environment such as dilution application is possible as described above. However, when diluted with water, the action of returning to the original water is accelerated according to the amount of dilution. The radical oxygen water produced in the present invention is controlled so as to maintain a neutral region.

  As described above, the technique of the present embodiment can be applied to an electrolysis apparatus that performs electrolysis of normal water. In addition, the present invention can be similarly applied to power generation of a fuel cell that is a reaction opposite to electrolysis. That is, even in a polymer electrolyte fuel cell using the reaction opposite to the electrolysis described above, the deterioration phenomenon occurring in the polymer electrolyte fuel cell can be similarly applied by applying the technique of the present embodiment. Can be suppressed. In that case, for example, in the water electrolysis apparatus main body 1a of FIG. 2, an oxidant (example: oxygen) and an electrolyte solution are provided on the cathode part 12 side (channel 3c), and a fuel (example: hydrogen gas) is provided on the anode part 11 side. + Water) is supplied, and heated to a predetermined temperature as necessary. Then, the hydrogen gas in the anode part 11 becomes hydrogen ions and moves in the ion conductive film 10 toward the cathode part 12. In this case, the cathode part 12 becomes the cathode part 12 (the cathode 8 is the cathode 8) of the polymer electrolyte fuel cell, and the anode part 11 becomes the anode part 11 (the anode 4 is the anode 4) of the polymer electrolyte fuel cell.

  The present invention is not limited to the above-described embodiment, and it is obvious that modifications and changes can be made without departing from the scope and spirit of the invention.

1 Water electrolysis device (1b Power supply unit 1a Water electrolysis device body)
2 Anode-side flow path (2a, 2e opening 2b, 2c, 2d flow path)
3 Cathode side flow path (3a, 3e opening 3b, 3c, 3d flow path)
4 Anode
5 Second electrode portion 6 First electrode portion 7 Non-conductive member 8 Cathode
9 Electrode part 10 Ion conductive membrane (10a 1st surface 10b 2nd surface)
11 Anode (Anode)
12 Cathode part (cathode part)
13 cells 21 water (supply water)
22 radical oxygen water 23 electrolyte solution 24 waste electrolyte solution 31 conversion unit 32 AC power supply 80 water electrolysis system 81, 82, 82a, 82b, 83, 84, 85, 86 piping 88 control unit 89 electrolyte solution supply unit 90 water supply unit 91 , 92, 93, 94, 95, 96, 97, 98, 99, 100 Valve 102 Density adjustment unit

Claims (14)

A water supply section for supplying water;
An electrolyte supply unit for supplying the electrolyte;
A water electrolysis device that is supplied with the water and the electrolytic solution, performs a process of electrolyzing the water, and sends out the water after the treatment;
The water electrolysis device is:
A solid electrolyte membrane having a first surface and a second surface opposite to the first surface;
An anode provided on the first surface side in contact with the first surface and through which the water flows;
A cathode provided on the second surface side, apart from the second surface;
A passage provided between the cathode and the second surface and through which the electrolyte flows,
The electrolytic solution contains chlorine ions,
The concentration of the chlorine ions is 50 mg / L or more and a saturation concentration or less. The water electrolysis system according to claim 1,
The electrolytic solution is a water electrolysis system in which a concentration of halogen ions other than the chlorine ions is 10 mg / L or less. The water electrolysis system according to claim 1 or 2,
The water electrolysis system wherein the residence time of the water at the anode is greater than 0 seconds and not more than 10 seconds. In the water electrolysis solution system according to any one of claims 1 to 3,
The chlorine ion is a water electrolysis system containing an alkali metal salt or a chloride ion of hydrochloric acid. In the water electrolysis system according to any one of claims 1 to 4,
The electrolytic solution further includes an electrolyte material for improving electrical conductivity. The water electrolysis system according to any one of claims 1 to 5,
The electrolysis solution is a buffer solution. The water electrolysis system according to any one of claims 1 to 6,
A water electrolysis system further comprising a first concentration adjusting unit for adjusting a chlorine ion concentration of the electrolytic solution. The water electrolysis system according to any one of claims 1 to 7,
A water electrolysis system further comprising a second concentration adjusting unit for adjusting a cation concentration of the electrolytic solution. The water electrolysis system according to claim 7 or 8,
The electrolytic solution supply unit is a water electrolysis system that receives the electrolytic solution sent from the water electrolytic device and supplies the received electrolytic solution to the water electrolytic device. The water electrolysis system according to any one of claims 1 to 9,
The amount of the electrolytic solution supplied to the water electrolysis device by the electrolytic solution supply unit is 1/1000 or more and 1/1 or less with respect to the amount of water supplied from the water supply unit to the water electrolysis device. Water electrolysis system. Flowing water through an anode provided in contact with the first surface of the solid electrolyte membrane and capable of flowing water;
Flowing an electrolytic solution between the second surface and a cathode provided on the second surface side of the solid electrolyte membrane away from the second surface;
Applying DC power between the anode and the cathode, and
The electrolytic solution contains chlorine ions,
The water electrolysis method, wherein the concentration of the chlorine ions is 50 mg / L or more and a saturation concentration or less. The water electrolysis method according to claim 11,
The electrolytic solution is a water electrolysis method wherein the concentration of halogen ions other than chlorine ions is 10 mg / L or less. The water electrolysis method according to claim 11 or 12,
The water electrolysis method, wherein a residence time of the water at the anode is greater than 0 seconds and 10 seconds or less. The water electrolysis method according to any one of claims 11 to 13,
A water electrolysis method further comprising the step of preparing an aqueous solution of an alkali metal salt containing hydrochloric acid or hydrochloric acid as an electrolytic solution.

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