Electrolyzed water generator, air purification device

Abstract

This invention provides a technology to suppress the contact of hypochlorite ions with the membrane surface of an anion exchange membrane. [Solution] The electrolytic cell 30 stores a first aqueous solution L1 containing chloride ions, and the supply tank 40 stores a second aqueous solution L2 containing chloride ions. A buffer layer 70 is provided between the electrolytic cell 30 and the supply tank 40 and stores the first aqueous solution L1. An anion exchange membrane 50 is provided to connect the buffer layer 70 and the supply tank 40 and is permeable to anions containing chloride ions. A diaphragm 72 is provided between the electrolytic cell 30 and the buffer layer 70. The electrolytic cell 30 generates hypochlorous acid by electrolysis of the first aqueous solution L1 without a diaphragm, and the supply tank 40 supplies chloride ions contained in the second aqueous solution L2 to the first aqueous solution L1 by electrolysis with a diaphragm, allowing them to pass through the anion exchange membrane 50, the buffer layer 70, and the diaphragm 72.

Description

[Technical Field]

[0001] The present disclosure relates to an electrolyzed water generator and a space purification device. [Background Art]

[0002] Electrolyzed water containing hypochlorous acid is produced using an electrolytic cell in which an anion exchange membrane is used as a diaphragm and an anode and the diaphragm are arranged in close proximity to each other. In order to suppress deterioration of the anion exchange membrane caused by chlorine gas generated on the anode surface, a protective membrane having a plurality of slit-shaped cuts is arranged between the anode and the anion exchange membrane (see, for example, Patent Document 1). [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2006-322053 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] Hypochlorous acid is generated when chlorine gas reacts with water. Furthermore, electrolysis can generate a water flow toward the membrane surface of the anion exchange membrane. Along with this water flow, hypochlorite ions move toward the anion exchange membrane side. Even when a protective membrane having a plurality of slit-shaped cuts is used for the anion exchange membrane, it is difficult to suppress contact of hypochlorite ions with the membrane surface of the anion exchange membrane.

[0005] The present disclosure has been made in view of the above problems, and provides a technique for suppressing contact of hypochlorite ions with the membrane surface of an anion exchange membrane. [Means for Solving the Problem]

[0006] To solve the above problems, an electrolytic water generator according to one embodiment of the present disclosure comprises an electrolytic cell for storing a first aqueous solution containing chloride ions, a supply tank for storing a second aqueous solution containing chloride ions, a buffer layer provided between the electrolytic cell and the supply tank for storing the first aqueous solution, an anion exchange membrane provided between the buffer layer and the supply tank and permeable to anions containing chloride ions, and a diaphragm provided between the electrolytic cell and the buffer layer. The electrolytic cell generates hypochlorous acid by electrolysis of the first aqueous solution without a diaphragm, and the supply tank supplies chloride ions contained in the second aqueous solution to the first aqueous solution by electrolysis with a diaphragm, allowing them to pass through the anion exchange membrane, the buffer layer, and the diaphragm.

[0007] Furthermore, any combination of the above components, as well as any conversion of the expressions of this disclosure between methods, apparatus, systems, recording media, or computer programs, are also valid forms of this disclosure. [Effects of the Invention]

[0008] This disclosure makes it possible to suppress contact of hypochlorite ions with the membrane surface of an anion exchange membrane. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a front cross-sectional view showing the air purification device according to Example 1. [Figure 2] Figure 2 is a magnified view of the anion exchange membrane, buffer layer, and diaphragm shown in Figure 1. [Figure 3] Figure 3 shows the change in the concentration of hypochlorous acid over time in the air purification device shown in Figure 1. [Figure 4] Figure 4 is a front cross-sectional view showing the air purification device according to Example 2. [Modes for carrying out the invention]

[0010] The following describes specific embodiments of this disclosure in detail with reference to the drawings. The x, y, and z coordinates shown in the figures are for convenience in explaining the positional relationships of the components. Unless otherwise specified, the positive z-axis direction is vertically upward. Also, the x and y planes are horizontal planes and are consistent across the drawings.

[0011] (Example 1) Figure 1 is a front cross-sectional view showing the air purification device 20. The air purification device 20 performs membrane-free electrolysis of a first aqueous solution L1 containing chloride ions in an electrolytic cell 30, which will be described later, to generate and volatilize hypochlorous acid. The air purification device 1 releases the generated hypochlorous acid into the external space R of the housing C that constitutes the air purification device 20, thereby removing bacteria, fungi, viruses, or odors contained in the air in the external space R of the air purification device 20. In addition, membrane-assisted electrolysis is performed to replenish the chloride ions contained in the first aqueous solution L1 that have been reduced by membrane-free electrolysis. Chloride ions contained in the second aqueous solution L2 stored in the supply tank 40 are supplied to the first aqueous solution L1 stored in the electrolytic cell 30 by permeating through the anion exchange membrane 50, buffer layer 70, and diaphragm 72.

[0012] The air purification device 20 is installed indoors. Preferably, the installation location of the air purification device 20 is a place where airflow can occur. More specifically, the installation location of the air purification device 20 is indoors. Specific examples of installation locations for the air purification device 20 include, for example, the inside of an air conditioner, the inside of a bathroom heater / dryer, around a fan, around a circulator, around a ceiling fan, inside a humidifier, inside a dehumidifier, inside an air purifier, and on a desk.

[0013] In this specification, "external space R" means the area outside the air purification device 20, that is, the area outside the housing C, for example, the indoor space. If the air purification device 20 is located inside equipment such as the air conditioner mentioned above, the area outside the housing C and the area inside the equipment are also included in "external space R".

[0014] As shown in Figure 1, the air purification device 20 comprises a housing C, an electrolytic cell 30, and a current control unit 60. The air purification device 20 may further include a supply tank 40, an anion exchange membrane 50, a buffer layer 70, and a diaphragm 72. The supply tank 40 and the anion exchange membrane 50 are used to supply chloride ions from the supply tank 40 to the electrolytic cell 30 in order to continue internal purification operation for a long period of time without supplying chloride ions to the electrolytic cell 30 from the outside. Furthermore, the buffer layer 70 and the diaphragm 72 are used to protect the anion exchange membrane 50.

[0015] The housing C is a box-shaped member that houses the electrolytic cell 30, the supply tank 40, the anion exchange membrane 50, the current control unit 60, the buffer layer 70, and the diaphragm 72. In other words, the air purification device 20 is a unit integrated by the housing C. The air purification device 20 is small in size, and when the shape of the housing C is a rectangular parallelepiped, it is for example about 10 cm × 7 cm × 4 cm.

[0016] The electrolytic cell 30 is a tank for storing a first aqueous solution L1 containing chloride ions and for producing hypochlorous acid by non-diaphragm electrolysis of the first aqueous solution L1. The supply tank 40 is a tank for storing a second aqueous solution L2 containing chloride ions and for supplying chloride ions contained in the second aqueous solution L2 to the first aqueous solution L1 by permeating the anion exchange membrane 50, buffer layer 70, and diaphragm 72 through diaphragm electrolysis. The buffer layer 70 and diaphragm 72 will be described later, so they will be omitted in the following description. More specifically, chloride ions contained in the second aqueous solution L2 are supplied to the first aqueous solution L1 by diaphragm electrolysis via the anion exchange membrane 50, which is provided to connect the electrolytic cell 30 and the supply tank 40. The anion exchange membrane 50 is permeable to anions, including chloride ions. The current control unit 60 controls non-diaphragm electrolysis and diaphragm electrolysis.

[0017] When assuming continuous use of 8 hours per day for one year, it is preferable that the volume of the supply tank 40 is about 12 times or more the volume of the electrolytic cell 30, for example. With such a volume ratio, the supply tank 40 can store the second aqueous solution L2 containing a sufficient amount of chloride ions required to be supplied to the first aqueous solution L1 in the electrolytic cell 30. Accordingly, chloride ions can be stably supplied from the second aqueous solution L2 stored in the supply tank 40 to the first aqueous solution L1 stored in the electrolytic cell 30.

[0018] The electrolytic cell 30 and the supply tank 40 are arranged in the order of the electrolytic cell 30 and the supply tank 40 from the negative side of the x-axis in a front view. An anion exchange membrane 50 is arranged between the electrolytic cell 30 and the supply tank 40 so as to connect the electrolytic cell 30 and the supply tank 40. For example, when the opposing surfaces of the electrolytic cell 30 and the supply tank 40 are formed of frame-shaped members, the anion exchange membrane 50 may be arranged so as to be fitted into the frame-shaped members. The current control unit 60 is arranged at any position within the housing C, but is not limited thereto, and may be arranged outside the housing C and connected via wireless communication or the like.

[0019] [Electrolytic cell 30] The electrolytic cell 30 is a tank for storing a first aqueous solution L1 containing chloride ions and generating hypochlorous acid by subjecting the first aqueous solution L1 to non-diaphragm electrolysis. The electrolytic cell 30 has, for example, a box shape, but any shape capable of storing the first aqueous solution L1 is acceptable. FIG. 1 shows a state where the first aqueous solution L1 is stored in the electrolytic cell 30. The volume of the first aqueous solution L1 stored in the electrolytic cell 30 is, for example, approximately 2 mL to 10 mL. The first aqueous solution L1 is, for example, an aqueous solution in which a conductive electrolyte is dissolved, that is, an electrolytic solution, specifically, a dilute chloride aqueous solution having a predetermined chloride ion concentration. More specifically, the first aqueous solution L1 is, for example, a dilute sodium chloride aqueous solution or a dilute potassium chloride aqueous solution.

[0020] The "predetermined chloride ion concentration" of the first aqueous solution L1 includes both a chloride ion concentration having a predetermined numerical range and a chloride ion concentration having a predetermined numerical value. More specifically, the chloride ion concentration of the first aqueous solution L1 may be, for example, 17 mmol / L to 1500 mmol / L, or 171 mmol / L. In other words, for example, the concentration of a dilute sodium chloride aqueous solution or a dilute potassium chloride aqueous solution may be 17 mmol / L to 1500 mmol / L, or 171 mmol / L. By setting the predetermined chloride ion concentration to the said numerical range or numerical value, it is possible to generate hypochlorous acid necessary for purifying the external space R while simultaneously suppressing the generation of chlorine that may be generated.

[0021] The electrolytic cell 30 includes an electrolytic cell-side anode 31, an electrolytic cell-side cathode 32, an air supply unit 33, a blower pipe 34, an electrolytic cell-side internal space 35, a water recovery unit 36, and a discharge port 37. The electrolytic cell 30 may further include a water level detection unit 38.

[0022] The electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32 are a pair of electrodes used for the electrolysis of the first aqueous solution L1. Insoluble electrodes may be used as the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32. More specifically, for example, platinum-iridium titanium electrodes, platinum electrodes, ruthenium titanium electrodes, or iridium titanium oxide electrodes may be used. Alternatively, the electrolytic cell-side cathode 32 may be a titanium electrode, iron electrode, tin electrode, nickel electrode, or an alloy of the aforementioned metals, each having an oxide film formed on its surface. An example of a case where the electrolytic cell-side cathode 32 is a metal alloy is a nickel-titanium alloy or a titanium electrode with tin oxide as a catalyst. Iron electrodes with an oxide film formed on them contain both FeO and Fe2O3. The shape of the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32 may be plate-shaped, mesh-shaped, or rod-shaped.

[0023] There is no diaphragm, such as an ion exchange membrane, between the electrolytic cell anode 31 and the electrolytic cell cathode 32. In other words, the electrolysis of the first aqueous solution L1 performed using the pair of electrolytic cell anodes 31 and cathode 32 is diaphragm-free electrolysis. Hypochlorous acid gas, which is used for purifying the external space R, is generated by the diaphragm-free electrolysis of the first aqueous solution L1 performed using the pair of electrolytic cell anodes 31 and cathode 32.

[0024] The air supply unit 33 is a blower, such as a locomotive blower, that introduces air from the external space R into the electrolytic cell 30.

[0025] The air blower pipe 34 is a tubular member that connects the air supply unit 33 and the electrolytic cell 30. One end of the air supply unit 33 is located on the side of the external space R, and the other end is connected to the air blower pipe 34 side. One end of the air blower pipe 34 is connected to the side of the air supply unit 33, and the other end is connected to the side of the electrolytic cell 30. The end of the air blower pipe 34 located on the side of the electrolytic cell 30 is connected to the electrolytic cell 30 such that it is located below (negative side of the z axis) the liquid level S1 of the first aqueous solution L1 stored in the electrolytic cell 30.

[0026] The air supply unit 33 supplies air from the external space R to the first aqueous solution L1 stored in the electrolytic cell 30 via the blower pipe 34. When the end of the blower pipe 34 is positioned below the liquid level S1 of the first aqueous solution L1 stored in the electrolytic cell 30 (negative z-axis side), the air introduced into the first aqueous solution L1 via the air supply unit 33 and the blower pipe 34 is released into the first aqueous solution L1 as bubbles B. A moisture-permeable waterproof membrane (not shown) may be placed over the entire diameter of the blower pipe 34. The moisture-permeable waterproof membrane is a membrane that allows air, which is a gas supplied from the external space R, and the moisture (water vapor) contained in that air to pass through, but does not allow the first aqueous solution L1, which is a liquid, to pass through. The placement of this moisture-permeable waterproof membrane prevents backflow of the first aqueous solution L1 from the electrolytic cell 30 to the blower pipe 34.

[0027] The electrolytic cell-side internal space 35 is an upper space (space on the positive z-axis side) formed above the liquid surface S1 of the first aqueous solution L1 when the first aqueous solution L1 is stored in the electrolytic cell 30. In other words, the first aqueous solution L1 is not stored up to the upper interior surface of the electrolytic cell 30 (the xy-plane on the positive z-axis side), and the electrolytic cell 30 has the electrolytic cell-side internal space 35.

[0028] The water recovery unit 36 ​​is a component that recovers moisture contained in the air that flows through the inside of the air purification device 20 and is released from the electrolytic cell 30 into the external space R as a liquid and returns it to the electrolytic cell 30. The water recovery unit 36 ​​is, for example, a Peltier element that can cool and condense moisture contained in the air into water droplets. When the water recovery unit 36 ​​is a Peltier element, the Peltier element has a heat dissipation surface and a heat absorption surface, and a cooling heat sink is provided on the heat absorption surface. The cooling heat sink can cool and condense moisture contained in the air passing through the cooling heat sink, turning it into water droplets.

[0029] The water recovery unit 36 ​​may be located at the discharge port 37 through which the air passes when it is released to the external space R, in order to recover moisture contained in the air circulating inside the air purification device 20. When the water recovery unit 36 ​​is located at the discharge port 37, moisture contained in the air that has circulated inside the air purification device 20 can be recovered efficiently. The water recovery unit 36 ​​may be located at any position in the internal space 35 on the electrolytic cell side.

[0030] The discharge port 37 is an opening for releasing mixed air M, which is a mixture of air flowing in from the air supply unit 33 and hypochlorous acid generated from the first aqueous solution L1 by membraneless electrolysis, into the external space R of the housing C. In Figure 1, as an example, the discharge port 37 is provided on the upper surface of the electrolytic cell 30 (the xy plane on the positive z-axis side), but it is sufficient that it is positioned above the liquid level S1 of the first aqueous solution L1. The shape of the discharge port 37 is cylindrical, including, for example, cylindrical or rectangular tubes. If the upper surface of the electrolytic cell 30 (the surface on the positive z-axis side) is close to the ceiling surface of the housing C, the discharge port 37 may be a hole-like opening provided in a part of the upper surface of the electrolytic cell 30. Alternatively, the discharge port 37 and the upper surface of the housing C (the surface on the positive z-axis side) may be formed as a single integrated unit.

[0031] The discharge port 37 may be equipped with an openable / closable or removable cover (not shown). The cover may be kept closed when transporting, moving, or installing the air purification device 20, and may be opened or removed when using the air purification device 20.

[0032] Next, we will explain the sequence of operations (purification operation) for supplying the hypochlorous acid gas generated by the air purification device 20 to the external space R. In the air purification device 20 according to this embodiment, air introduced from the external space R flows through the electrolytic cell 30 and is supplied to the external space R together with hypochlorous acid.

[0033] The airflow path A, indicated by the white arrow and the upward-sloping arrow in Figure 1, is a series of paths through which air supplied from the external space R to the air purification device 20 flows through the electrolytic cell 30 and is released back to the external space R as mixed air M containing hypochlorous acid. In other words, airflow path A shows the flow of air from the external space R, the air supply unit 33, the blower pipe 34, the first aqueous solution L1 stored in the electrolytic cell 30, the internal space on the electrolytic cell side 35, the water recovery unit 36, the discharge port 37, and back to the external space R.

[0034] More specifically, in airflow channel A, as shown in Figure 1, air supplied to the electrolytic cell 30 from the external space R via the air supply unit 33 and the air blower 34 is released as bubbles B into the first aqueous solution L1 stored in the electrolytic cell 30. In other words, bubbles B are generated by bubbling the first aqueous solution L1 with air introduced from the external space R. The released bubbles B are mixed with hypochlorous acid generated by the membraneless electrolysis of the first aqueous solution L1 to form mixed air M.

[0035] Here, the hypochlorous acid produced by the non-diaphragm electrolysis of the first aqueous solution L1 includes both hypochlorous acid dissolved in the first aqueous solution L1 and hypochlorous acid gas that has volatilized and gasified into the internal space 35 on the electrolytic cell side. The hypochlorous acid dissolved in the first aqueous solution L1 is mixed with bubbles B and released as mixed air M from the outlet 37 through the water recovery unit 36 ​​to the external space R. The hypochlorous acid gas that has volatilized and gasified into the internal space 35 on the electrolytic cell side is mixed with bubbles B which are mixed with hypochlorous acid and released as mixed air M from the outlet 37 through the water recovery unit 36 ​​to the external space R.

[0036] When the air purification device 20 is equipped with a water recovery unit 36, the hypochlorous acid gas (mixed air M) flows through the water recovery unit 36, and the water contained in the hypochlorous acid gas is recovered into the electrolytic cell 30. Along with the recovery of this water by the water recovery unit 36, metal ions such as sodium ions contained in the water contained in the hypochlorous acid gas are also recovered into the electrolytic cell 30. Therefore, hypochlorous acid gas with reduced water content and lower metal ion content can be supplied to the external space R. Metal ion components are included in the electrolyte components. More specifically, metal ions are sodium ions, potassium ions, calcium ions, or magnesium ions.

[0037] By generating bubbles B in the first aqueous solution L1 through bubbling, the bubbles B float towards the liquid surface S1 due to buoyancy, and as they do so, hypochlorous acid and bubbles B come into gas-liquid contact, allowing the bubbles B to absorb hypochlorous acid. In other words, compared to gas-liquid contact between air and the liquid surface S1 of the first aqueous solution L1, the gas-liquid contact by generating bubbles B in the first aqueous solution L1 through bubbling allows bubbles B to absorb more hypochlorous acid and release it into the external space R as mixed air M. The mixed air M contains water evaporated from the first aqueous solution L1, but this water contained in the mixed air M is recovered by the water recovery unit 36 ​​and returned to the first aqueous solution L1 as water droplets.

[0038] The mixed air M containing hypochlorous acid, released from the outlet 37 into the external space R of the air purification device 20, purifies the external space R. More specifically, the mixed air M containing hypochlorous acid also removes bacteria, fungi, viruses, or odors contained in the air of the external space R of the enclosure C.

[0039] The electrolytic cell 30 may further include a water level detection unit 38. The water level detection unit 38 detects the position of the liquid level S1 in the first aqueous solution L1. The water level detection unit 38 is, for example, a water level sensor. The water level detection unit 38 is positioned at least above (on the positive z-axis side of) the upper ends (the portions on the positive z-axis side of) the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32.

[0040] If the air purification device 20 is equipped with a water level detection unit 38, the water recovery unit 36 ​​recovers moisture from the mixed air M based on the position of the liquid level S1 detected by the water level detection unit 38 and supplies water to the electrolytic cell 30. More specifically, the water recovery unit 36 ​​supplies water to the electrolytic cell 30 so as not to fall below the upper ends (the portion on the positive z-axis) of the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32. Furthermore, the water recovery unit 36 ​​supplies water to the electrolytic cell 30 so as not to fall below the upper end (the portion on the positive z-axis) of the air blower pipe 34 connected to the electrolytic cell 30.

[0041] If the air purification device 20 is equipped with a water recovery unit 36 ​​and a water level detection unit 38, the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32 can remain immersed in the first aqueous solution L1. Therefore, exposure of the electrolytic cell-side anode 31 and the electrolytic cell-side cathode 32 to the air as the first aqueous solution L1 decreases can be suppressed, and the electrolytic efficiency of membrane-free electrolysis can be maintained. The supply tank 40 may also be equipped with a water recovery unit and a water level detection unit similar to those of the electrolytic cell 30.

[0042] The supply tank 40 and anion exchange membrane 50, which will be described next, are used to supply chloride ions from the supply tank 40 to the electrolytic cell 30 in order to continue the purification operation without supplying chloride ions from the outside to the electrolytic cell 30 for a long period of time, and to continue the purification of the external space R.

[0043] [Supply tank 40] The supply tank 40 is a tank for storing the second aqueous solution L2 containing chloride ions and for supplying the chloride ions contained in the second aqueous solution L2 to the first aqueous solution L1. Figure 1 shows the state in which the second aqueous solution L2 is stored in the supply tank 40.

[0044] As the solute for the second aqueous solution L2, it is preferable to use a substance whose GHS (Globally Harmonized System of Classification and Labelling of Chemicals) classification is as safe as that of sodium chloride, in order to ensure safety in the event of leakage. Specifically, the second aqueous solution L2 is an aqueous metal chloride solution containing metal ions and chloride ions. The second aqueous solution L2 is subjected to diaphragm electrolysis via an anion exchange membrane 50, which will be described later. This reaction between the metal ions contained in the second aqueous solution L2 and the hydroxide ions generated by the diaphragm electrolysis forms a precipitate of metal hydroxide. Preferably, the second aqueous solution L2 is a high-concentration magnesium chloride aqueous solution or a saturated magnesium chloride aqueous solution.

[0045] When a magnesium chloride aqueous solution is used as the second aqueous solution L2, the mass percentage concentration of the magnesium chloride aqueous solution is, for example, 1% to 35%. As an example, when the second aqueous solution L2 is a magnesium chloride aqueous solution, diaphragm electrolysis is performed, causing the magnesium ions contained in the magnesium chloride aqueous solution to react with the hydroxide ions produced by the diaphragm electrolysis to form a magnesium hydroxide precipitate. The "precipitate" of magnesium hydroxide includes hard, sandy, colloidal, slurry-like, or gel-like forms, and the aqueous solution may appear cloudy.

[0046] The supply tank 40 comprises a supply tank-side cathode 41, a supply tank-side internal space 42, and an outlet 43. The supply tank-side cathode 41 is an electrode used in diaphragm electrolysis via an anion exchange membrane 50, as a pair with the electrolytic cell-side anode 31. Chloride ions are supplied from the second aqueous solution L2 to the first aqueous solution L1 by diaphragm electrolysis of the second aqueous solution L2, which is performed using the pair of supply tank-side cathodes 41 and the electrolytic cell-side anode 31.

[0047] An insoluble electrode may be used as the supply tank side cathode 41. More specifically, for example, a titanium electrode, a platinum-iridium titanium electrode, a platinum electrode, a ruthenium titanium electrode, or an iridium titanium oxide electrode may be used. The shape of the supply tank side cathode 41 may be any of the following, such as a plate, mesh, or rod, similar to the shapes of the electrolytic cell side anode 31 and the electrolytic cell side cathode 32.

[0048] The internal space 42 on the supply tank side is the upper space (space on the positive z-axis side) formed above the liquid surface S2 of the second aqueous solution L2 when the second aqueous solution L2 is stored in the supply tank 40. In other words, the second aqueous solution L2 is not stored up to the upper interior surface of the supply tank 40 (the xy-plane on the positive z-axis side), and the supply tank 40 has the internal space 42 on the supply tank side.

[0049] The outlet 43 is an opening for discharging hydrogen gas, generated by the diaphragm electrolysis of the second aqueous solution L2, to the external space R of the housing C. The outlet 43 is, for example, a check valve. When a check valve is used as the outlet 43, the hydrogen gas inside the supply tank 40 is discharged to the external space R, but the inflow of gases such as air from the external space R can be suppressed. As the diaphragm electrolysis of the second aqueous solution L2 is repeated, hydrogen gas accumulates in the internal space 42 on the supply tank side, and the internal pressure of the supply tank 40 increases. This pressure causes the check valve of the outlet 43 to open, and the hydrogen gas is discharged to the external space R of the supply tank 40.

[0050] If the supply tank 40 does not have an outlet 43, an air passage (not shown) may be provided to connect the internal space 35 on the electrolytic cell side and the internal space 42 on the supply tank side. If an air passage is provided between the electrolytic cell 30 and the supply tank 40, the hydrogen gas may be discharged in the following order: internal space 42 on the supply tank side, air passage, internal space 35 on the electrolytic cell side, and outlet 37.

[0051] The anion exchange membrane 50 is provided to connect the electrolytic cell 30 and the supply tank 40, and is a membrane-like member that allows anions to pass through based on the voltage applied between the electrolytic cell 30 and the supply tank 40. More specifically, when a voltage is applied between the anode 31 on the electrolytic cell side and the cathode 41 on the supply tank side, diaphragm electrolysis is performed through the anion exchange membrane 50. Through diaphragm electrolysis using the anode 31 on the electrolytic cell side and the cathode 41 on the supply tank side, chloride ions contained in the second aqueous solution L2 permeate the anion exchange membrane 50 and are supplied to the first aqueous solution L1 (indicated by the negative x-axis direction and thick black arrow).

[0052] The anion exchange membrane 50 in this embodiment is not an anion exchange membrane of the type that allows anions to permeate by osmosis without using electricity. Furthermore, magnesium ions, which are cations, do not permeate the anion exchange membrane 50. More specifically, when chloride ions contained in the second aqueous solution L2 are supplied to the first aqueous solution L1 by diaphragm electrolysis using the electrolytic cell side anode 31 and the supply tank side cathode 41, magnesium ions, which are cations, do not permeate the anion exchange membrane 50. The anion exchange membrane 50 is, for example, a hydrocarbon-based anion exchange membrane composed of a hydrocarbon polymer material. Various types of hydrocarbon-based anion exchange membranes exist with different properties. In this embodiment, it is preferable to use a hydrocarbon-based anion exchange membrane 50 that has, for example, the property of selective permeability of monovalent ions, alkali resistance, or high temperature resistance.

[0053] The anion exchange membrane 50 is positioned between the electrolytic cell 30 and the supply tank 40. If the surfaces of the electrolytic cell 30 and the supply tank 40 facing each other are formed by a frame-shaped member, the anion exchange membrane 50 may be positioned so as to be fitted into the frame-shaped member. In other words, the electrolytic cell 30 and the supply tank 40 are connected via the anion exchange membrane 50 in a way that allows anions to pass through.

[0054] Furthermore, the chloride ion concentration of the second aqueous solution L2 may be approximately the same as that of the first aqueous solution L1, and a high-concentration chloride aqueous solution supply tank may be provided to supply a high-concentration chloride aqueous solution to the second aqueous solution L2.

[0055] The current control unit 60 includes wiring 61, 62, and 63. Wiring 61, 62, and 63 are lines through which current flows. The electrolytic cell-side anode 31 is electrically connected to the current control unit 60 via wiring 61, the electrolytic cell-side cathode 32 via wiring 62, and the supply tank-side cathode 41 via wiring 63.

[0056] The current control unit 60 controls the currents used in non-diaphragm electrolysis and diaphragm electrolysis. More specifically, it controls the first current used in non-diaphragm electrolysis and the second current used in diaphragm electrolysis. In other words, the current control unit 60 controls the chemical reactions that occur in non-diaphragm electrolysis and diaphragm electrolysis by controlling the first current and the second current.

[0057] In the purification operation, diaphragm electrolysis is performed to supply chloride ions contained in the second aqueous solution L2 stored in the supply tank 40 to the first aqueous solution L1 stored in the electrolytic cell 30 by permeating the anion exchange membrane 50, in order to replenish the chloride ions contained in the first aqueous solution L1 that have been reduced by non-diaphragm electrolysis. Specifically, the current control unit 60 increases the amount of chloride ions supplied from the second aqueous solution L2 to the first aqueous solution L1 by, for example, increasing the second current.

[0058] Furthermore, during the purification operation, the current control unit 60 controls the first current to replenish the chloride ions contained in the first aqueous solution L1 that have decreased due to membraneless electrolysis, thereby supplying chloride ions contained in the second aqueous solution L2 to the first aqueous solution L1 by permeating the anion exchange membrane 50. The current control unit 60 flows the first current and the second current in a predetermined ratio so that the hypochlorous acid concentration of the first aqueous solution L1 is maintained at a predetermined concentration or within a predetermined range, while replenishing the chloride ions that have decreased in the first aqueous solution L1. The predetermined concentration is the Cl concentration in the electrolytic cell 30. - This is the concentration at which the apparent increase or decrease does not occur. In other words, the predetermined concentration is the concentration of Cl stored in the first aqueous solution L1. - This is the concentration at which the initial concentration of the substance does not appear to change. The Cl stored in the first aqueous solution L1 -The specified concentration range is a Cl concentration sufficient to stably supply hypochlorous acid gas from the electrolytic cell 30. - This is the range of concentrations.

[0059] The following reaction equation 1 shows the equilibrium reaction equation for the hypochlorous acid generation reaction. Cl2 + H2O ⇔ HCl + HClO ... (Reaction Equation 1) Cl supplied from the second aqueous solution L2 to the first aqueous solution L1 - Depending on the increase or decrease of , the equilibrium state may shift to the right or to the left. The concentration of hypochlorous acid in the first aqueous solution L1 stored in the electrolytic cell 30 is maintained at a predetermined concentration, that is, the Cl in the electrolytic cell 30 - The current control unit 60 controls the current so that it does not appear to increase or decrease.

[0060] [Buffer layer 70 and diaphragm 72] If a large amount of hypochlorite ions reach the anion exchange membrane 50 after electrolysis has stopped and come into contact with the anion exchange membrane 50, the anion exchange membrane 50 will deteriorate. To suppress the deterioration of the anion exchange membrane 50, it is desirable to suppress the reach of a large amount of hypochlorite ions to the anion exchange membrane 50. For this purpose, a buffer layer 70 is provided on the electrolytic cell 30 side of the anion exchange membrane 50 in the air purification device 20, and a diaphragm 72 is provided between the buffer layer 70 and the electrolytic cell 30. In other words, two layers, the buffer layer 70 and the diaphragm 72, are arranged between the electrolytic cell 30 and the anion exchange membrane 50.

[0061] Figure 2 is a partially enlarged view of the anion exchange membrane 50, buffer layer 70, and diaphragm 72. The buffer layer 70 is a hollow space connecting the electrolytic cell 30 and the supply tank 40, and is, for example, a tube. The anion exchange membrane 50 is installed at the opening of the connection between the buffer layer 70 and the supply tank 40, and the diaphragm 72 is installed at the opening of the connection between the buffer layer 70 and the electrolytic cell 30. The shape of the buffer layer 70 is not limited to this; for example, a part of the electrolytic cell 30 may be partitioned by the diaphragm 72, and the partitioned part of the electrolytic cell 30 may be used as the buffer layer 70. The first aqueous solution L1 is stored in the buffer layer 70. Therefore, the first aqueous solution L1 stored in the electrolytic cell 30 and the first aqueous solution L1 stored in the buffer layer 70 are separated by the diaphragm 72.

[0062] The diaphragm 72 is a porous membrane. More specifically, the diaphragm 72 is a semipermeable membrane having a network of micropores 74. It has liquid-retaining properties due to the surface tension generated on its fine porous surface, but it has low water permeability and does not actively allow water to pass through. Therefore, the diaphragm 72 can suppress collisions of ions or water particles with the anion exchange membrane 50.

[0063] The diaphragm 72 is one of the following: a microfiltration (MF) membrane, an ultrafiltration (UF) membrane, or a nanofiltration (NF) membrane. If the diaphragm 72 is a microfiltration membrane, the diameter of the micropores 74 is, for example, 100 nm to 10000 nm. If the diaphragm 72 is an ultrafiltration membrane, the diameter of the micropores 74 is, for example, 10 nm to 1000 nm. If the diaphragm 72 is a nanofiltration membrane, the diameter of the micropores 74 is, for example, 1 nm to 100 nm. The material constituting the diaphragm 72 is, for example, PET (Poly Ethylene Terephthalate), PTFE (PolyTetraFluoroEthylene), or PVDF (PolyVinylidene DiFluoride). Furthermore, the shape of the mesh-like micropores 74 may be symmetrical (e.g., lattice-like) or asymmetrical. The surface of the diaphragm 72 may be treated to make it hydrophilic in order to further improve the conductivity between the electrolytic cell 30 and the supply tank 40.

[0064] When diaphragm-free electrolysis is performed in the electrolytic cell 30, hypochlorite ions are attracted to the anode 31 on the electrolytic cell side and do not actively move toward the diaphragm 72, buffer layer 70, and anion exchange membrane 50. Therefore, there is almost no contact between the hypochlorite ions and the anion exchange membrane 50. In addition, since the diaphragm 72 has liquid retention capacity due to the micropores 74, contact between hypochlorite ions moved by the water flow and the anion exchange membrane 50, as well as the physical load on the anion exchange membrane 50 by the water flow, is reduced. By providing the buffer layer 70 and the diaphragm 72, the influence of hypochlorous acid generated in the electrolytic cell 30 on the anion exchange membrane 50 and the influence of water flow that may occur due to electrolysis are suppressed. This suppresses the deterioration of the anion exchange membrane 50.

[0065] On the other hand, if membrane-free electrolysis is not performed in the electrolytic cell 30, hypochlorite ions move to the anion exchange membrane 50 side by natural diffusion. Figure 3 shows the change in hypochlorous acid concentration in the air purification device 20 over time. The horizontal axis shows the elapsed time since membrane-free electrolysis was stopped, and the vertical axis shows the hypochlorous acid concentration. In the graph of Figure 3, the hypochlorous acid concentration in the electrolytic cell 30 is shown as "hypochlorous acid concentration 80". When membrane-free electrolysis is stopped, hypochlorite ions naturally diffuse while volatilizing, self-decomposing, etc., so the hypochlorous acid concentration 80 in the electrolytic cell 30 decreases over time. In addition, the liquid retention capacity of the membrane 72 makes it difficult for hypochlorite ions to pass through the membrane 72.

[0066] In the graph in Figure 3, the concentration of hypochlorous acid on the diaphragm 72 side of the buffer layer 70 is shown as "hypochlorous acid concentration 82". At the time when the non-diaphragm electrolysis is stopped, few hypochlorite ions reach the buffer layer 70 due to the liquid retention capacity of the diaphragm 72. As time passes, the number of hypochlorite ions passing through the diaphragm 72 increases, and the hypochlorous acid concentration 82 in the buffer layer 70 also increases. However, as the hypochlorous acid concentration 80 in the electrolytic cell 30 itself decreases, the hypochlorous acid concentration 82 in the buffer layer 70 also decreases.

[0067] In the graph in Figure 3, the concentration of hypochlorous acid on the surface of the anion exchange membrane 50 on the buffer layer 70 side is shown as "hypochlorous acid concentration 84". The presence of the buffer layer 70 delays the time it takes for hypochlorite ions to reach the anion exchange membrane 50. As a result, the diffusion of hypochlorite ions progresses within the buffer layer 70 before the hypochlorite ions reach the anion exchange membrane 50, so the hypochlorous acid concentration 84 on the surface of the anion exchange membrane 50 is lower than the hypochlorous acid concentration 82 in the buffer layer 70. Consequently, the deterioration of the anion exchange membrane 50 is suppressed. In the first aqueous solution L1, ionized hypochlorous acid and non-ionized hypochlorous acid exist in equilibrium. The above explanation focused on ionized hypochlorous acid, but the same mechanism can be used to reduce the concentration of non-ionized hypochlorous acid when it reaches the surface of the anion exchange membrane 50.

[0068] Furthermore, the presence of the diaphragm 72 suppresses the passage of bubbles (water flow) that may be generated by diaphragm-free electrolysis through the diaphragm 72 to the buffer layer 70. As a result, the influence of the water flow generated by diaphragm-free electrolysis on the anion exchange membrane 50 is suppressed. In other words, by providing the diaphragm 72 and the buffer layer 70, the deterioration of the anion exchange membrane 50 by hypochlorite ions is suppressed. Therefore, the diaphragm 72 can be said to be a porous membrane having a mesh-like structure of fine pores 74 that prevents the concentration of hypochlorite ions from exceeding a threshold when they reach the anion exchange membrane 50 after diaphragm-free electrolysis in the electrolytic cell 30 has stopped, by permeating through the diaphragm 72 and the buffer layer 70 from the electrolytic cell 30. Here, the "threshold" of the hypochlorite ion concentration is a concentration that can suppress the deterioration of the anion exchange membrane 50. For example, if the hypochlorite ion concentration in the electrolytic cell 30 is 1000 ppm, and the anion exchange membrane 50 can be used without deterioration for 10 years, and the lifespan of the air purification device 20 is 5 years, then the threshold can be set to 2000 ppm. The "threshold" for the hypochlorite ion concentration is a value determined in advance through experiments, etc., and can be changed as appropriate according to the expected lifespan of the air purification device 20.

[0069] The subject of the apparatus, system, or method in this disclosure comprises a computer. The functions of the subject of the apparatus, system, or method in this disclosure are realized by the computer executing a program. The computer comprises a processor as its main hardware component, which operates according to the program. The processor is of any type as long as it can realize its functions by executing the program. The processor consists of one or more electronic circuits, including semiconductor integrated circuits (ICs) or LSIs (Large Scale Integrations). Multiple electronic circuits may be integrated on one chip or provided on multiple chips. Multiple chips may be aggregated in one device or provided on multiple devices. The program is recorded on a non-temporary recording medium such as a ROM, optical disc, or hard disk drive that is readable by the computer. The program may be pre-stored on the recording medium or supplied to the recording medium via a wide-area communication network, including the Internet.

[0070] According to this embodiment, since a buffer layer 70 and a diaphragm 72 are provided, the time it takes for hypochlorite ions generated in the electrolytic cell 30 to reach the anion exchange membrane 50 can be delayed. Also, because the time it takes for hypochlorite ions to reach the anion exchange membrane 50 is delayed, contact of hypochlorite ions with the membrane surface of the anion exchange membrane 50 can be suppressed by self-decomposition or natural diffusion of hypochlorite ions. In addition, because contact of hypochlorite ions with the membrane surface of the anion exchange membrane 50 is suppressed, the deterioration of the anion exchange membrane 50 can be suppressed. Furthermore, because the time it takes for hypochlorite ions to reach the anion exchange membrane 50 is delayed, the increase in the concentration of hypochlorous acid in the anion exchange membrane 50 can be suppressed.

[0071] Furthermore, because it is equipped with a buffer layer 70 and a diaphragm 72, physical loads such as water flow and bubbles generated in the electrolytic cell 30 can be suppressed. Also, because physical loads such as water flow and bubbles generated in the electrolytic cell 30 are suppressed, the deterioration of the anion exchange membrane 50 can be suppressed. In addition, because the deterioration of the anion exchange membrane 50 is suppressed, it is possible to operate with a stable chloride ion concentration for a long period of time without supplying chloride from outside the device, and a stable supply of hypochlorous acid gas can be achieved. Furthermore, because the deterioration of the anion exchange membrane 50 is suppressed, the frequency of maintenance can be reduced.

[0072] Furthermore, since the diaphragm 72 is either a microfiltration (MF) membrane, an ultrafiltration (UF) membrane, or a nanofiltration (NF) membrane, it can protect the anion exchange membrane 50. Also, since the surface of the diaphragm 72 is hydrophilized, it can conduct electricity. In addition, to replenish the chloride ions contained in the first aqueous solution L1 that have decreased due to diaphragm-free electrolysis, chloride ions contained in the second aqueous solution L2 stored in the supply tank 40 are supplied to the first aqueous solution L1, so that the purification operation can be continued for a long period of time without supplying chloride ions to the electrolytic cell 30 from the outside, and the purification of the external space R can be continued. Furthermore, gas-liquid contact is performed by generating bubbles B in the first aqueous solution L1 by bubbling, so that more hypochlorous acid can be taken into the bubbles B and released into the external space R as mixed air M. The mixed air M containing hypochlorous acid released into the external space R can purify the external space R.

[0073] An overview of one aspect of this disclosure is as follows: (Item 1) An electrolytic cell (30) for storing a first aqueous solution (L1) containing chloride ions, A supply tank (40) for storing a second aqueous solution (L2) containing chloride ions, A buffer layer (70) is provided between the electrolytic cell (30) and the supply tank (40) for storing the first aqueous solution (L1), An anion exchange membrane (50) is provided between the buffer layer (70) and the supply tank (40) and is permeable to anions containing chloride ions, A diaphragm (72) is provided between the electrolytic cell (30) and the buffer layer (70), Equipped with, The electrolytic cell (30) generates hypochlorous acid by performing membrane-free electrolysis of the first aqueous solution (L1), The supply tank (40) supplies the chloride ions contained in the second aqueous solution (L2) to the first aqueous solution (L1) by diaphragm electrolysis, through the anion exchange membrane (50), the buffer layer (70), and the diaphragm (72). Electrolyzed water generator.

[0074] (Item 2) The diaphragm (72) is a porous membrane having a mesh-like structure of micropores that prevents the concentration of hypochlorite ions from exceeding a threshold value when they reach the anion exchange membrane (50) after the diaphragm-free electrolysis in the electrolytic cell (30) has stopped, by passing through the diaphragm (72) and the buffer layer (70) from the electrolytic cell (30). The electrolytic water generator described in item 1.

[0075] (Item 3) The aforementioned diaphragm (72) is one of the following: a microfiltration (MF) membrane, an ultrafiltration (UF) membrane, or a nanofiltration (NF) membrane. The electrolytic water generator described in item 1.

[0076] (Item 4) The surface of the diaphragm (72) is subjected to a hydrophilic treatment. The electrolytic water generator described in item 1.

[0077] (Item 9) The electrolytic water generator is provided as described in any one of items 1 to 8, Air introduced from the indoor space flows through the electrolytic cell (30) and is released into the indoor space together with the hypochlorous acid in a purification operation. To compensate for the chloride ions contained in the first aqueous solution (L1) that have been reduced by the aforementioned membrane-free electrolysis, the chloride ions contained in the second aqueous solution (L2) stored in the supply tank (40) are supplied to the first aqueous solution (L1) stored in the electrolytic cell (30) by permeating through the anion exchange membrane (50) and the protective membrane (70). Air purification device (20).

[0078] (Item 10) The air supplied to the electrolytic cell (30) is released as bubbles (B) into the first aqueous solution (L1). The released bubbles (B) are mixed with the hypochlorous acid, and the resulting mixed air (M) is released into the indoor space. The air purification device (20) described in item 9.

[0079] (Example 2) Next, Example 2 will be described. Example 2 relates to a space purification device 20 similar to that of Example 1. In Example 1, in order to suppress the deterioration of the anion exchange membrane 50 by hypochlorite ions, a buffer layer 70 is provided on the electrolytic cell 30 side of the anion exchange membrane 50, and a porous membrane (diaphragm 72) is provided between the buffer layer 70 and the electrolytic cell 30. When this porous membrane is used for a certain period of time, the porous membrane deteriorates due to hypochlorite ions. In such cases, the protective effect on the anion exchange membrane 50 may be insufficient. To prevent this, the protective effect can be increased by reducing the area of ​​the porous membrane or increasing the number of porous layers. However, reducing the area of ​​the porous membrane or increasing the number of porous layers increases the voltage for electrolysis. Also, as described in Example 1, it is possible to suppress the deterioration of the anion exchange membrane 50 with a porous membrane, but as mentioned above, even before the porous membrane deteriorates, the anion exchange membrane 50 may deteriorate due to hypochlorite ions that have passed through the porous membrane by diffusion.

[0080] On the other hand, compared to porous membranes, anion exchange membranes offer superior protection and can protect the anion exchange membrane 50 while suppressing the voltage increase required for electrolysis. Therefore, in Example 2, to protect the anion exchange membrane 50, a protective anion exchange membrane (hereinafter referred to as the "protective anion exchange membrane") separate from the anion exchange membrane 50 is added to extend the lifespan of the anion exchange membrane 50. Adding the protective anion exchange membrane increases the time it takes for hypochlorite ions that have passed through the protective anion exchange membrane to reach the anion exchange membrane 50 compared to when only a porous membrane is present. As a result, the hypochlorous acid concentration on the surface of the anion exchange membrane 50 is reduced due to the natural decay of hypochlorite ions.

[0081] Figure 4 is a front cross-sectional view showing the air purification device 20. In the air purification device 20, a buffer layer 70 is provided on the electrolytic cell 30 side of the anion exchange membrane 50, and a diaphragm 72 is provided between the buffer layer 70 and the electrolytic cell 30. Here, the diaphragm 72 includes a protective anion exchange membrane 76 and a porous membrane 78, and the porous membrane 78 is positioned between the electrolytic cell 30 and the protective anion exchange membrane 76. The porous membrane 78 corresponds to the diaphragm 72 of Example 1. Therefore, the porous membrane 78 is a semipermeable membrane having a mesh-like structure of fine pores 74 (not shown), and has liquid retention properties due to the surface tension generated on the fine porous surface, but has low water permeability and does not actively allow water to pass through.

[0082] The protective anion exchange membrane 76 is a different anion exchange membrane from the anion exchange membrane 50. The protective anion exchange membrane 76 may have oxidation resistance comparable to that of the anion exchange membrane 50, but it is more preferable that it be composed of a material with higher oxidation resistance than the anion exchange membrane 50. Materials with higher oxidation resistance than the anion exchange membrane 50 include, for example, fully fluorinated anion exchange membranes (perfluoroanion exchange membranes) and partially fluorinated anion exchange membranes. The former is composed of a polymer material in which the main chain is fully fluorinated, and the latter is composed of a polymer material in which the main chain contains at least one fluorine atom. In other words, the protective anion exchange membrane 76 can be said to be a fluorine-based anion exchange membrane. On the other hand, the anion exchange membrane 50 is a hydrocarbon-based anion exchange membrane, as described above. Here, the diaphragm 72 may not include the porous membrane 78 and may consist only of the protective anion exchange membrane 76.

[0083] In this embodiment, since the diaphragm 72 includes a protective anion exchange membrane 76, the diffusion of hypochlorite ions can be suppressed while suppressing the voltage rise during diaphragm electrolysis compared to using only the porous membrane 78. Furthermore, since the diffusion of hypochlorite ions is suppressed, the deterioration of the anion exchange membrane 50 can be further suppressed. In addition, since the diaphragm 72 includes both the protective anion exchange membrane 76 and the porous membrane 78, the diffusion of hypochlorite ions into the buffer layer 70 due to the deterioration of the protective anion exchange membrane 76 can be suppressed. Furthermore, since the diffusion of hypochlorite ions into the buffer layer 70 due to the deterioration of the protective anion exchange membrane 76 is suppressed, the deterioration of the anion exchange membrane 50 can be further suppressed. In addition, since the oxidation resistance of the protective anion exchange membrane 76 is higher than that of the anion exchange membrane 50, the diffusion of hypochlorite ions into the buffer layer due to the deterioration of the protective anion exchange membrane 76 can be suppressed.

[0084] An overview of one aspect of this disclosure is as follows: (Item 5) The electrolytic water generator according to item 1, wherein the diaphragm (72) includes a protective anion exchange membrane (76) different from the anion exchange membrane (50).

[0085] (Item 6) The diaphragm (72) further comprises a porous membrane (78) having a network of micropores, The electrolytic water generating apparatus according to item 5, wherein the porous membrane (78) is disposed between the electrolytic cell and the protective anion exchange membrane (76).

[0086] (Item 7) The electrolytic water generator according to item 5, wherein the protective anion exchange membrane (76) is made of a material with higher oxidation resistance than the anion exchange membrane (50).

[0087] (Item 8) The electrolytic water generator according to item 6, wherein the protective anion exchange membrane (76) is made of a material with higher oxidation resistance than the anion exchange membrane (50).

[0088] The present disclosure has been described above based on examples. These examples are illustrative, and it will be understood by those skilled in the art that various modifications are possible for each component or combination of processing steps, and that such modifications are also within the scope of the present disclosure.

[0089] Examples 1 and 2 describe the air purification device 20. However, the invention is not limited to this; for example, the electrolytic water generator within the air purification device 20 may also be the subject. The electrolytic water generator, excluding the air supply unit 33, blower pipe 34, water recovery unit 36, and discharge port 37 from Figure 1, includes a discharge pipe for discharging a solution containing hypochlorous acid gas (hereinafter referred to as "electrolytic water") generated by membrane-free electrolysis in the electrolytic cell 30. In other words, the electrolytic water generator discharges electrolytic water without releasing mixed air M containing hypochlorous acid. The buffer layer 70 and diaphragm 72 are configured in the same way as in the examples. According to this modification, the buffer layer 70 and diaphragm 72 are used to protect the anion exchange membrane 50 in the electrolytic water generator, thus expanding the scope of application of the example. [Explanation of symbols]

[0090] 20 Space purification device, 30 Electrolytic cell, 31 Electrolytic cell side anode, 32 Electrolytic cell side cathode, 33 Air supply unit, 34 Air blower, 35 Electrolytic cell side internal space, 36 Water recovery unit, 37 Discharge port, 38 Water level detection unit, 40 Supply tank, 41 Supply tank side cathode, 42 Supply tank side internal space, 43 Discharge port, 50 Anion exchange membrane, 60 Current control unit, 61, 62, 63 Wiring, 70 Buffer layer, 72 Diaphragm, 74 Micropores, R External space.

Claims

1. An electrolytic cell for storing a first aqueous solution containing chloride ions, A supply tank for storing a second aqueous solution containing chloride ions, A buffer layer is provided between the electrolytic cell and the supply tank for storing the first aqueous solution, An anion exchange membrane is provided between the buffer layer and the supply tank, and is permeable to anions including chloride ions. A diaphragm is provided between the electrolytic cell and the buffer layer, Equipped with, The electrolytic cell generates hypochlorous acid by performing membrane-free electrolysis of the first aqueous solution. The supply tank supplies the chloride ions contained in the second aqueous solution to the first aqueous solution by diaphragm electrolysis, through the anion exchange membrane, the buffer layer, and the diaphragm. Electrolyzed water generator.

2. The aforementioned diaphragm is a porous membrane having a network of micropores that prevents the concentration of hypochlorite ions from exceeding a threshold value when they reach the anion exchange membrane after the diaphragm-free electrolysis in the electrolytic cell has stopped, by passing through the diaphragm and the buffer layer from the electrolytic cell. The electrolytic water generator according to claim 1.

3. The aforementioned membrane is one of the following: a microfiltration (MF) membrane, an ultrafiltration (UF) membrane, or a nanofiltration (NF) membrane. The electrolytic water generator according to claim 1.

4. The surface of the aforementioned diaphragm is subjected to a hydrophilic treatment. The electrolytic water generator according to claim 1.

5. The electrolytic water generator according to claim 1, wherein the diaphragm includes a protective anion exchange membrane different from the anion exchange membrane.

6. The diaphragm further comprises a porous membrane having a network of micropores, The electrolytic water generating apparatus according to claim 5, wherein the porous membrane is disposed between the electrolytic cell and the protective anion exchange membrane.

7. The electrolytic water generator according to claim 5, wherein the protective anion exchange membrane is made of a material with higher oxidation resistance than the anion exchange membrane.

8. The electrolytic water generator according to claim 6, wherein the protective anion exchange membrane is made of a material with higher oxidation resistance than the anion exchange membrane.

9. The electrolytic water generator is provided according to any one of claims 1 to 8, Air introduced from the indoor space flows through the electrolytic cell and is released into the indoor space together with the hypochlorous acid in a purification operation. To compensate for the chloride ions contained in the first aqueous solution that have been reduced by the aforementioned membrane-free electrolysis, the chloride ions contained in the second aqueous solution stored in the supply tank are supplied to the first aqueous solution stored in the electrolytic cell by permeating the anion exchange membrane, the buffer layer, and the membrane. Air purification device.

10. The air supplied to the electrolytic cell is released into the first aqueous solution as bubbles. The released bubbles are mixed with the hypochlorous acid, and the resulting mixed air is released into the indoor space. The air purification device according to claim 9.

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