Space purifier

Abstract

To provide a space purifier capable of stably generating a desired amount of hypochlorous acid gas without supplying water solution containing chloride ions from outside for a long period of time.SOLUTION: A space purifier 1 includes: an electrolytic tank 10 for storing a first water solution L1 containing chloride ions; a supply tank 20 storing a second water solution L2 and supplying the chloride ions to the first water solution L1; an electrolytic tank side positive electrode 11 and an electrolytic tank side negative electrode 12 provided on the electrolytic tank 10; a supply tank side negative electrode 21 provided on the supply tank 20; a negative ion exchange membrane 30; a diaphragmless electrolytic part E1 diaphragmless-electrolyzing the first water solution and generating the hypochlorous acid; a diaphragm electrolytic part E2 performing the diaphragm electrolysis via the negative ion exchange membrane; and a water recovery part 14. Air introduced from an outer space R to the supply tank side internal space 23 as an upper space of a liquid surface S2 of the second water solution L2 stored in the supply tank 20 is circulated in the order of the electrolytic tank 10 and the water recovery part 14 and is discharged to the outer space R.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a space purification device. [Background technology]

[0002] Patent Document 1 discloses an air purifying device that uses hypochlorous acid generated by electrolyzing an aqueous sodium chloride solution to remove bacteria, fungi, viruses, odors, and the like contained in the air. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-174032 Summary of the Invention [Problem to be solved by the invention]

[0004] When a conventional space purification device is downsized, the tank that stores the aqueous solution used for electrolysis also becomes smaller. This downsizing of the tank reduces the amount of aqueous solution that can be stored compared to conventional space purification devices. Therefore, when electrolysis is repeatedly performed in a downsized space purification device, the chloride ion concentration in the aqueous solution tends to decrease, resulting in an unstable amount of hypochlorous acid generated.

[0005] The present invention has been made in consideration of the above problems, and provides a space purification device that can stably generate a desired amount of hypochlorous acid gas for a long period of time without supplying an aqueous solution containing chloride ions from the outside. [Means for solving the problem]

[0006] The spatial purification device of the present invention includes an electrolytic cell for storing a first aqueous solution containing chloride ions; a supply cell for storing a second aqueous solution containing a higher concentration of chloride ions than the first aqueous solution and for supplying chloride ions to the first aqueous solution; an electrolytic cell-side anode and an electrolytic cell-side cathode provided in the electrolytic cell; a supply cell-side cathode provided in the supply cell; an anion exchange membrane connecting the electrolytic cell and the supply cell to allow anions to pass therethrough based on a voltage applied between the electrolytic cell-side anode and the supply cell-side cathode; a diaphragm-less electrolysis unit provided in the electrolytic cell that produces hypochlorous acid by performing membrane-less electrolysis of the first aqueous solution by passing a first current between the electrolytic cell-side anode and the electrolytic cell-side cathode; a diaphragm-equipped electrolysis unit provided between the electrolytic cell and the supply cell that performs membrane-equipped electrolysis via the anion exchange membrane by passing a second current between the electrolytic cell-side anode and the supply cell-side cathode; and a water recovery unit that recovers moisture contained in circulating air as a liquid and returns it to the electrolytic cell. Air introduced from the external space into the supply tank side internal space, which is the space above the liquid surface of the second aqueous solution stored in the supply tank, flows through the electrolytic cell and the water recovery section in this order, and is then released into the external space. [Effects of the Invention]

[0007] The present invention provides a space purification device that can stably generate a desired amount of hypochlorous acid gas for a long period of time without supplying an aqueous solution containing chloride ions from the outside. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a front cross-sectional view showing a space purification device according to the first embodiment. [Figure 2] FIG. 2 is a partial cross-sectional plan view taken along line II-II in FIG. [Figure 3] FIG. 3 is a partial cross-sectional plan view taken along line III-III in FIG. [Figure 4] Figure 4 shows a list of reaction formulas that occur in the membraneless electrolysis section. [Figure 5] FIG. 5 is a reaction formula showing the ratio of the current flowing in the electrolytic section without a diaphragm to the current flowing in the electrolytic section with a diaphragm. [Figure 6]FIG. 6 shows a list of reaction formulas that occur in the membrane electrolysis section. [Figure 7] FIG. 7 is a block diagram illustrating a current control unit according to the embodiment. [Figure 8] FIG. 8 is a front cross-sectional view showing the space purification device according to the second embodiment. [Figure 9] FIG. 9 is a front cross-sectional view showing a space purification device according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Specific embodiments of the present invention will be described in detail below with reference to the drawings. The xyz coordinates shown in the drawings are for the convenience of explaining the positional relationships of the components. Unless otherwise specified, the positive z-axis direction is vertically upward. The xy plane is a horizontal plane, and is common to all drawings.

[0010] <First Embodiment> 1 is a front cross-sectional view showing a space purifying device 1 according to Embodiment 1. The space purifying device 1 performs electrolysis on a first aqueous solution L1 containing chloride ions in an electrolytic bath 10 (described later) to generate and volatilize hypochlorous acid. The space purifying device 1 removes bacteria, fungi, viruses, odors, and the like contained in the air in the external space of the space purifying device 1 by causing the volatilized hypochlorous acid to flow into the external space of a housing C that constitutes the space purifying device 1.

[0011] The space purification device 1 is installed indoors. The installation location of the space purification device 1 is preferably a location where air flow can occur. More specifically, the installation location of the space purification device 1 is indoors, and more specifically, includes, for example, inside an air conditioner, which is an air conditioner, around an electric fan, around a circulator, around a ceiling fan, inside a humidifier, inside an air purifier, and on a desk.

[0012] As shown in FIG. 1, the spatial purification device 1 includes a housing C, an electrolytic cell 10, a supply cell 20, an anion exchange membrane 30, a first connection unit 31, and a current control unit 40.

[0013] The housing C houses the electrolytic cell 10, the supply cell 20, the anion exchange membrane 30, the first connection part 31, and the current control part 40. In other words, the space purification device 1 may be an integrated unit formed by the housing C. The shape of the housing C can be changed appropriately depending on the location where the space purification device 1 is installed, and may be, for example, a rectangular parallelepiped or cylindrical shape. The space purification device 1 has a small size that can be stored inside an air conditioner, for example, approximately 10 cm x 7 cm x 4 cm.

[0014] Assuming continuous use for eight hours a day for one year, the respective volumes of the electrolytic cell 10 and the supply cell 20 are preferably set so that the volume of the supply cell 20 is at least about 12 times the volume of the electrolytic cell 10. Such a volume ratio allows the supply cell 20 to store the second aqueous solution L2 containing a sufficient amount of chloride ions required to be supplied to the first aqueous solution L1 of the electrolytic cell 10. Therefore, chloride ions can be stably supplied from the second aqueous solution L2 stored in the supply cell 20 to the first aqueous solution L1 stored in the electrolytic cell 10. The amount of the first aqueous solution L1 stored in the electrolytic cell 10 is, for example, about 2 mL to 10 mL.

[0015] The electrolytic cell 10 is a cell for storing a first aqueous solution L1 containing chloride ions. The electrolytic cell 10 has, for example, a box-like shape. FIG. 1 shows the first aqueous solution L1 stored in the electrolytic cell 10. The first aqueous solution L1 is, for example, an aqueous solution in which an electrically conductive electrolyte is dissolved, and more specifically, a dilute chloride aqueous solution having a predetermined chloride ion concentration. More specifically, the first aqueous solution L1 is, for example, a sodium chloride aqueous solution or a dilute potassium chloride aqueous solution.

[0016] The "predetermined chloride ion concentration" of the first aqueous solution L1 includes both a chloride ion concentration within a predetermined 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, 1 g / L to 50 g / L, or may be 10 g / L. In other words, the mass percent concentration of the dilute sodium chloride aqueous solution or the dilute potassium chloride aqueous solution may be, for example, 0.1% to 5%, or may be 5%. By setting the predetermined chloride ion concentration within this numerical range or numerical value, it is possible to generate hypochlorous acid necessary for space purification while suppressing the generation of chlorine that may be generated at the same time.

[0017] The electrolytic cell 10 comprises an electrolytic cell-side anode 11, an electrolytic cell-side cathode 12, an electrolytic cell-side internal space 13, a water recovery unit 14, and an outlet 15. The electrolytic cell 10 may further comprise a water level detection unit 16.

[0018] The electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 are a pair of electrodes used in the electrolysis of the first aqueous solution L1. As shown in Fig. 1, no diaphragm such as an ion exchange membrane is provided between the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12. In other words, the electrolysis of the first aqueous solution L1 performed using the pair of the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 is membrane-less electrolysis. Hypochlorous acid, which is used for space purification, is produced by the membrane-less electrolysis of the first aqueous solution L1 performed using the pair of the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12.

[0019] The electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 each have a plate-like shape. That is, the electrolytic cell-side anode 11 is an electrolytic cell-side anode plate having a plate-like shape, and the electrolytic cell-side cathode 12 is an electrolytic cell-side cathode plate having a plate-like shape. Plate-like shapes include rectangular and oblong shapes. Details of the structure of each electrode will be described later with reference to FIG. 3.

[0020] The electrolytic cell-side internal space 13 is an upper space (space on the positive z-axis side) formed above the liquid level S1 of the first aqueous solution L1 when the first aqueous solution L1 is stored in the electrolytic cell 10. In other words, the first aqueous solution L1 is not stored up to the internal upper surface of the electrolytic cell 10 (xy plane on the positive z-axis side), and the electrolytic cell 10 has the electrolytic cell-side internal space 13.

[0021] The water recovery unit 14 is a component that flows through the interior of the space purification device 1 and recovers moisture contained in the air released from the electrolytic cell 10 to the external space R as a liquid and returns it to the electrolytic cell 10. The water recovery unit 14 is, for example, a Peltier element that can cool the moisture contained in the air and condense it into water droplets. In order to recover moisture contained in the air flowing through the interior of the space purification device 1, the water recovery unit 14 may be disposed at the discharge port 15 through which the air passes when it is released to the external space R. When the water recovery unit 14 is disposed at the discharge port 15, it is possible to efficiently recover moisture contained in the air that has flowed through the interior of the space purification device 1. The water recovery unit 14 may also be disposed in a part of the electrolytic cell-side internal space 13.

[0022] The outlet 15 is an opening for discharging mixed air, which is a mixture of air flowing in from an air supply unit 22 included in the supply tank 20 (described later) and hypochlorous acid generated from the first aqueous solution L1 by diaphragm-less electrolysis, into the external space R of the casing C. In FIG. 1 , the outlet 15 is provided on the top surface (xy plane on the positive side of the z-axis) of the electrolytic cell 10 as an example, but it need only be located above the liquid level S1 of the first aqueous solution L1. The shape of the outlet 15 is tubular, and includes, for example, a cylindrical or rectangular tubular shape. When the top surface (the surface on the positive side of the z-axis) of the electrolytic cell 10 is close to the ceiling surface of the casing C, the outlet 15 may be a hole-like opening provided in a part of the top surface of the electrolytic cell 10. Alternatively, the outlet 15 and the top surface (the surface on the positive side of the z-axis) of the casing C may be formed integrally.

[0023] The outlet 15 may be provided with an openable or detachable lid (not shown). The lid is closed when the space purification device 1 is transported, moved, or installed, and is opened when the space purification device 1 is in use. It may be configured to be removable or detachable.

[0024] The water level detector 16 detects the position of the liquid level S1 in the first aqueous solution L1. The water level detector 16 is, for example, a water level sensor. The water level detector 16 is disposed above (on the positive z-axis side) the upper ends (on the positive z-axis side) of at least the electrolytic cell-side anode 11, the electrolytic cell-side cathode 12, and the supply cell-side cathode 21.

[0025] When the space purification device 1 is equipped with a water level detection unit 16, the water recovery unit 14 supplies water to the electrolytic cell 10 based on the position of the liquid level S1 detected by the water level detection unit 16. More specifically, the water recovery unit 14 supplies water to the electrolytic cell 10 so that the water level does not fall below the upper ends (the parts on the positive side of the z-axis) of the electrolytic cell-side anode 11, the electrolytic cell-side cathode 12, and the supply cell-side cathode 21. Furthermore, one end (the end on the positive side of the x-axis) of a first connection unit 31 (described later) is connected to the electrolytic cell 10 at a position below the liquid level S1 of the first aqueous solution L1 stored in the electrolytic cell 10. The water recovery unit 14 supplies water to the electrolytic cell 10 so that the water level does not fall below the upper end (the part on the positive side of the z-axis) of the first connection unit 31.

[0026] When the space purification device 1 is equipped with the water level detection unit 16, the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 can be maintained immersed in the first aqueous solution L1. This prevents the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 from being exposed to air due to a decrease in the first aqueous solution L1, and maintains the electrolysis efficiency of the diaphragm-less electrolysis.

[0027] The supply tank 20 is a tank for storing the second aqueous solution L2 containing chloride ions. The chloride ions contained in the second aqueous solution L2 in the supply tank 20 permeate through the anion exchange membrane 30 and are supplied to the first aqueous solution L1 in the electrolytic tank 10.

[0028] The supply tank 20 is a tank for storing a second aqueous solution L2 containing chloride ions and supplying the chloride ions to the first aqueous solution L1. FIG. 1 shows the second aqueous solution L2 stored in the supply tank 20. The chloride ion concentration of the second aqueous solution L2 is higher than that of the first aqueous solution L1. To ensure safety in the event of leakage, the solute of the second aqueous solution L2 is preferably a substance classified under the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) as being as safe as sodium chloride. Specifically, the second aqueous solution L2 is a metal chloride aqueous solution containing metal ions and chloride ions. The second aqueous solution L2 is subjected to membrane electrolysis, as described below, whereby the metal ions contained in the second aqueous solution L2 react with hydroxide ions generated by the membrane electrolysis to form a metal hydroxide precipitate. Preferably, the second aqueous solution L2 is a high-concentration magnesium chloride aqueous solution or a saturated magnesium chloride aqueous solution. When a magnesium chloride aqueous solution is used as the second aqueous solution L2, the mass percent concentration of the magnesium chloride aqueous solution is, for example, 1% to 35%. For example, when the second aqueous solution L2 is a magnesium chloride aqueous solution, by performing the membrane electrolysis described below, magnesium ions contained in the magnesium chloride aqueous solution react with hydroxide ions generated by the membrane electrolysis to form a precipitate of magnesium hydroxide. The "precipitate" of magnesium hydroxide includes hard sand, colloid, slurry, and gel forms, as well as a cloudy aqueous solution.

[0029] The supply tank 20 includes a supply tank-side cathode 21, an air supply unit 22, and a supply tank-side internal space 23. The supply tank 20 may further include a lid unit 24.

[0030] The supply cell side cathode 21 is an electrode used in a pair with the electrolytic cell side anode 11 for electrolysis of the second aqueous solution L2. As shown in FIG. 1, an anion exchange membrane 30 is disposed between the electrolytic cell side anode 11 and the supply cell side cathode 21. That is, the electrolysis of the second aqueous solution L2 performed using the pair of the electrolytic cell side anode 11 and the supply cell side cathode 21 is membrane electrolysis. That is, the electrolytic cell side anode 11 is used for both membraneless electrolysis and membrane electrolysis. By the membrane electrolysis of the second aqueous solution L2 carried out using the anode 11 and the supply tank side cathode 21, chloride ions are supplied from the second aqueous solution L2 to the first aqueous solution L1.

[0031] The supply tank side cathode 21 is a supply tank side cathode plate having a plate shape. The plate shape includes a rectangular shape and an oblong shape. The structure of each electrode will be described in detail later with reference to FIG. 3.

[0032] The air supply unit 22 introduces air from the external space R into the supply tank 20. More specifically, the air supply unit 22 introduces the air from the external space R into a supply tank-side internal space 23 (described later). The air supply unit 22 is a blower or a predetermined opening. The air supply unit 22 is disposed above the liquid level S2 of the second aqueous solution L2 in the supply tank 20. When the relative humidity of the air in the external space R is lower than a predetermined humidity, the air supply unit 22 stops supplying air to the supply tank-side internal space 23. When the second aqueous solution L2 stored in the supply tank 20 is an aqueous magnesium chloride solution, the "predetermined humidity" refers to a relative humidity of the air in the external space R being lower than 35%, for example. By stopping the supply of air from the air supply unit 22 to the supply tank-side internal space 23 when the relative humidity of the air in the external space R is lower than the predetermined humidity, excessive evaporation of the second aqueous solution L2 stored in the supply tank 20 can be suppressed. Furthermore, when the relative humidity of the air in the external space R is less than 35%, the supply of air to the supply tank side internal space 23 by the air supply unit 22 is stopped, thereby making it possible to suppress the deposition of magnesium chloride.

[0033] If the air supply unit 22 is a blower, it is preferably placed on the yz plane at the negative end of the x-axis or on the xy plane at the negative end of the x-axis and the positive end of the z-axis in order to improve the air flow inside the space purification device 1. If the air supply unit 22 is an opening, it is preferably placed in a location that can circulate air to the opening, such as a circulator, electric fan, or ceiling fan placed inside an air conditioner or outside the space purification device 1.

[0034] The supply tank-side internal space 23 is an upper space (space on the positive z-axis side) formed above the liquid level S2 of the second aqueous solution L2 when the second aqueous solution L2 is stored in the supply tank 20. In other words, the second aqueous solution L2 is not stored up to the internal upper surface (xy plane on the positive z-axis side) of the supply tank 20, and the supply tank-side internal space 23 is present. Air is supplied from an air supply unit 22 to the supply tank-side internal space 23.

[0035] Here, the purification operation of the space purification device 1 may cause the liquid level S2 of the second aqueous solution L2 to rise and exceed a predetermined position (height in the z-axis direction) of the supply tank 20. The purification operation refers to the operation of purifying a space by the space purification device 1. Examples of cases where the "purification operation of the space purification device 1 causes the liquid level S2 of the second aqueous solution L2 to rise" include when water permeates the anion exchange membrane 30 from the first aqueous solution L1 to the second aqueous solution L2 due to a concentration difference between the first aqueous solution L1 and the second aqueous solution L2, and when the second aqueous solution L2 is a magnesium chloride aqueous solution, when the second aqueous solution L2 absorbs moisture contained in the air supplied from the external space R.

[0036] The state in which the liquid level S2 of the second aqueous solution L2 exceeds a predetermined position in the supply tank 20 refers to a state in which the amount of the second aqueous solution L2 has unintentionally increased in the space purification device 1, resulting in an excessive amount of the second aqueous solution L2. The air supplied from the air supply unit 22 to the supply tank-side internal space 23 flows over the liquid level S2 of the second aqueous solution L2, thereby promoting evaporation of the second aqueous solution L2. In this way, when the amount of the second aqueous solution L2 becomes excessive, the air supplied by the air supply unit 22 and flowing through the supply tank-side internal space 23 can promote evaporation of the excess second aqueous solution L2.

[0037] The evaporated water content of the second aqueous solution L2 is recovered by a water recovery unit 14 provided in the electrolytic cell 10 and dripped as a liquid into the electrolytic cell 10. Therefore, even if water permeates the anion exchange membrane 30 from the first aqueous solution L1 to the second aqueous solution L2, the provision of the water recovery unit 14 can prevent the amount of the first aqueous solution L1 in the electrolytic cell 10 from decreasing excessively.

[0038] The lid 24 is a plate-like member having a predetermined opening 25 and extending along the xy plane. The lid 24 is, for example, a solid member molded from a resin material that is insoluble in the second aqueous solution L2, or a membrane-like member such as a silicone membrane that allows passage of air bubbles that may be generated from the second aqueous solution L2. The end of the lid 24 on the negative x-axis is connected to the inner wall surface of the supply tank 20, but the end on the positive x-axis is not connected to the inner wall surface of the supply tank 20. The lid 24 is disposed at a predetermined position in the supply tank-side internal space 23. The "predetermined position" where the lid 24 is disposed refers to a position above the liquid level S2 of the second aqueous solution L2 when the space purification device 1 starts purifying. The start of purifying operation refers to the initial state of the space purification device 1.

[0039] At the start of the purification operation, the lid 24 is positioned in the z-axis direction above (on the positive side of the z-axis) the position of the liquid level S2 of the second aqueous solution L2 in the z-axis direction, and is fixed at this fixed position. If the lid 24 is not provided, the air supplied from the air supply unit 22 flows through the supply tank side internal space 23, causing the air to flow over the liquid level S2 of the second aqueous solution L2 and causing the second aqueous solution L2 to evaporate, but the provision of the lid 24 makes it possible to suppress excessive evaporation of the second aqueous solution L2.

[0040] Since the lid portion 24 is fixed at the above-mentioned fixed position, when the liquid level S2 of the second aqueous solution L2 rises due to the purification operation of the space purification device 1, the opening 25 causes the second aqueous solution L2 to flow out to the upper surface side of the lid portion 24 (the xy plane on the positive side of the z axis).

[0041] The state in which the liquid level S2 of the second aqueous solution L2 exceeds the lid portion 24 refers to a state in which the amount of the second aqueous solution L2 in the space purification device 1 has unintentionally increased, resulting in an excessive amount of the second aqueous solution L2. Here, air supplied from the air supply unit 22 flows over the liquid level S2 of the second aqueous solution L2 that has flowed out to the upper surface of the lid portion 24, thereby promoting evaporation of the second aqueous solution L2. In this way, the lid portion 24 having the opening 25 can suppress excessive evaporation of the second aqueous solution L2, while promoting evaporation of the excess second aqueous solution L2 that has flowed out to the upper surface of the lid portion 24 when the amount of the second aqueous solution L2 becomes excessive. The water from the evaporated second aqueous solution L2 is recovered by the water recovery unit 14 provided in the electrolytic cell 10 and dripped into the electrolytic cell 10 as a liquid. Therefore, even if water passes through the anion exchange membrane 30 from the first aqueous solution L1 to the second aqueous solution L2, the provision of the lid portion 24 and the water recovery portion 14 can prevent the amount of the first aqueous solution L1 in the electrolytic cell 10 from decreasing excessively.

[0042] Here, reference is made to FIG. 2 to explain the details of lid portion 24 and opening 25. FIG. 2 is a partial cross-sectional plan view taken along line II-II in FIG. 1. As shown in FIG. 2, lid portion 24 is rectangular in plan view. The width W1 of lid portion 24 in the y-axis direction is arranged to match the width W1 of the inner wall surface of supply tank 20 in the y-axis direction. The width W2 of lid portion 24 in the x-axis direction is arranged to be smaller than the width W4 of the inner wall surface of supply tank 20 in the x-axis direction. Opening 25 is rectangular in plan view, for example, and is arranged with a predetermined width W3 extending from the end of the inner wall surface of supply tank 20 on the positive side of the x-axis toward the negative direction of the x-axis.

[0043] As shown in FIG. 2, the opening 25 is preferably arranged along the y-axis direction of the supply tank 20. More specifically, for example, the opening 25 may be arranged at a single location along the y-axis direction at the end of the inner wall of the supply tank 20 on the positive side of the x-axis. A case where the liquid level S2 of the second aqueous solution L2 is below the fixed position of the lid 24, i.e., the liquid level S2 is located lower than the fixed position of the lid 24 (at a position on the negative side of the z-axis direction), will be described. Here, if openings are arranged at two or more locations in a plan view, for example, at the end of the inner wall of the supply tank 20 on the positive side of the x-axis and the end of the negative side of the x-axis, air may flow from the end on the negative side of the x-axis to the underside of the lid (negative side of the z-axis) and the end on the positive side of the x-axis. This may result in unintended evaporation of the second aqueous solution L2, resulting in excessive evaporation of the second aqueous solution L2. In contrast, the opening 25 according to this embodiment is arranged at a single location along the y-axis direction at the end on the positive side of the x-axis, which can suppress evaporation of the second aqueous solution L2 compared to when openings are arranged at two or more locations.

[0044] The position of opening 25 in the x-axis direction is not limited as long as it is arranged along the y-axis direction of supply tank 20. However, when opening 25 is arranged along the y-axis direction at the end of the inner wall surface of supply tank 20 on the positive side of the x-axis, as in the present embodiment, hydrogen generated at supply tank side cathode 21 becomes more likely to volatilize.

[0045] Although opening 25 has a rectangular shape in a plan view as an example, it is not limited thereto. Opening 25 may be located at the end of the inner wall surface of supply tank 20 on the positive side of the x-axis, and may be configured to allow the second aqueous solution L2 to flow out to the upper surface of lid 24 when the liquid level S2 of second aqueous solution L2 rises. For example, opening 25 may be a rectangle having a width smaller than width W1 in the y-axis direction, a plurality of rectangular tubular holes, a plurality of cylindrical holes, or a mesh-like shape.

[0046] Returning to Figure 1, the extension direction of lid portion 24 does not have to be along the xy plane, and lid portion 24 may be disposed at a predetermined inclination angle. The predetermined inclination angle may be an angle between -45 degrees and +45 degrees in a front view, with the end of lid portion 24 on the negative side of the x axis as the origin.

[0047] The anion exchange membrane 30 is a membranous member that connects the electrolytic cell 10 and the supply cell 20 in a manner that allows anions to pass therethrough, based on a voltage applied between the electrolytic cell 10 and the supply cell 20. More specifically, when a voltage is applied between the electrolytic cell-side anode 11 and the supply cell-side cathode 21 (described below), membrane-operated electrolysis occurs via the anion exchange membrane 30. By the membrane-operated electrolysis using the electrolytic cell-side anode 11 and the supply cell-side cathode 21, chloride ions contained in the second aqueous solution L2 permeate the anion exchange membrane 30 and are supplied to the first aqueous solution L1 (in the negative direction of the x-axis, indicated by a thick black arrow).

[0048] The anion exchange membrane 30 in this embodiment is not a type of anion exchange membrane that allows anions to permeate due to osmotic pressure without using electricity. Furthermore, magnesium ions, which are cations, do not permeate the anion exchange membrane 30. More specifically, when chloride ions contained in the second aqueous solution L2 are permeated through the anion exchange membrane 30 and supplied to the first aqueous solution L1 by membrane electrolysis using the electrolytic cell-side anode 11 and the supply cell-side cathode 21, magnesium ions, which are cations, do not permeate the anion exchange membrane 30. The anion exchange membrane 30 may be, for example, a hydrocarbon-based anion exchange membrane, and may include membranes that have monovalent anion-selective permeability, alkali resistance, and high-temperature resistance.

[0049] The anion exchange membrane 30 is disposed between the electrolytic cell 10 and the supply cell 20. For example, the surface of the electrolytic cell 10 facing the supply cell 20 (the yz plane on the positive side of the x-axis) and the surface of the supply cell 20 facing the electrolytic cell 10 (the yz plane on the negative side of the x-axis) may each be formed by a frame-shaped member. When the opposing surfaces of the electrolytic cell 10 and the supply cell 20 are each formed by a frame-shaped member, the anion exchange membrane 30 may be disposed so as to be fitted into the frame-shaped member.

[0050] The first connecting part 31 is a member that supplies air from the external space R into the first aqueous solution L1 in the electrolytic cell 10 via the air supply part 22 and the supply cell-side internal space 23. The first connecting part 31 is a tubular member that connects the electrolytic cell 10 and the supply cell 20. More specifically, one end (negative side of the x-axis) of the first connecting part 31 is connected to the supply cell-side internal space 23 of the supply cell 20, and the other end (positive side of the x-axis) is connected to the electrolytic cell 10 at a position below (negative side of the z-axis) the liquid level S1 of the first aqueous solution L1 stored in the electrolytic cell 10.

[0051] 1, the first connecting part 31 may have a shape that combines a cylindrical member extending along the x-axis direction with a cylindrical member that is L-shaped in front view, but is not limited to this. The first connecting part 31 may be a tubular member that connects the electrolytic cell 10 and the supply cell 20, and may be formed such that the position in the z-axis direction of the end connected to the supply cell side internal space 23 (the end on the negative side of the x-axis) is higher than the position in the z-axis direction of the end connected to the electrolytic cell 10 (the end on the positive side of the x-axis). It is sufficient to place it in

[0052] Current control unit 40 includes wiring 41, 42, and 43. Wiring 41, 42, and 43 are lines through which current flows. Electrolytic cell-side anode 11, electrolytic cell-side cathode 12, and supply cell-side cathode 21 are electrically connected to current control unit 40 via wiring 41, wiring 42, and wiring 43, respectively.

[0053] The current control unit 40 controls the current used in the diaphragmless electrolysis and the diaphragm-containing electrolysis. More specifically, the current control unit 40 controls the current used in the diaphragmless electrolysis, which is performed using a pair of electrolytic cell-side anode 11 and electrolytic cell-side cathode 12 disposed in the electrolytic cell 10. The current control unit 40 also controls the current used in the diaphragm-containing electrolysis, which is performed via an anion-exchange membrane 30 using a pair of electrolytic cell-side anode 11 and feed cell-side cathode 21, across the electrolytic cell 10 and the feed cell 20. The electrolytic cell-side anode 11 is used for both the diaphragm-less electrolysis and the diaphragm-containing electrolysis. In other words, the space purification device 1 according to this embodiment has one anode and two cathodes, for a total of three electrodes. Because the feed cell 20 has only cathodes, chlorine is not generated within the feed cell 20 by a chemical reaction, which will be described later.

[0054] The first air flow path A1 is a series of paths through which air supplied to the space purification device 1 from the external space R flows through the device and is released into the external space R as mixed air M containing hypochlorous acid. Specifically, the first air flow path A1 shows the air flow from the external space R, the air supply unit 22 disposed in the supply tank 10, the supply tank-side internal space 23, the first connecting unit 31, the first aqueous solution L1 stored in the electrolytic tank 10, the electrolytic tank-side internal space 13, the water recovery unit 14, the discharge port 15, and back to the external space R. That is, the first air flow path A1 is a path through which air introduced from the external space R flows through the supply tank 20, is supplied to the electrolytic tank 10, and is then released into the external space R. The air flowing through the first air flow path A1 is indicated by hollow arrows. More specifically, in the first air flow path A1, as shown in FIG. 1 , air introduced from the external space R into the supply tank-side internal space 23 via the air supply unit 22 is released as bubbles B into the first aqueous solution L1 stored in the electrolytic tank 10 via the first connecting unit 31. In other words, the first aqueous solution L1 is bubbled with air introduced from the external space R, thereby generating bubbles B.

[0055] Here, the hypochlorous acid generated by membrane-less electrolysis includes both hypochlorous acid dissolved in the first aqueous solution L1 and hypochlorous acid gas that has volatilized and gasified into the electrolytic cell-side internal space 13. The hypochlorous acid dissolved in the first aqueous solution L1 is mixed with bubbles B and is released as mixed air M from the discharge port 15 into the external space R via the water recovery unit 14. The hypochlorous acid gas that has volatilized and gasified into the electrolytic cell-side internal space 13 is mixed with the bubbles B mixed with hypochlorous acid and is released as mixed air M from the discharge port 15 into the external space R via the water recovery unit 14.

[0056] By generating bubbles B in the first aqueous solution L1 by bubbling, the bubbles B rise to the liquid surface S1 due to buoyancy, and as the bubbles B rise to the liquid surface S1, the hypochlorous acid and the bubbles B come into gas-liquid contact, allowing the hypochlorous acid to be captured in the bubbles B. In other words, compared to gas-liquid contact between air and the liquid surface S1 of the first aqueous solution L1, gas-liquid contact resulting from the generation of bubbles B in the first aqueous solution L1 by bubbling allows more hypochlorous acid to be captured in the bubbles B and released to the external space R as mixed air M. The mixed air M contains moisture that has evaporated from the first aqueous solution L1 and the second aqueous solution L2, and this moisture contained in the mixed air M is recovered by the water recovery unit 14 and returned to the first aqueous solution L1 as water droplets.

[0057] The mixed air M containing hypochlorous acid is released from the outlet 15 into the external space R of the space purification device 1 to purify the external space R. That is, the mixed air M containing hypochlorous acid removes bacteria, fungi, viruses, odors, and the like contained in the air in the external space R of the housing C.

[0058] Next, the details of the structure of each electrode, as well as the diaphragm-less electrolysis section E1 and the diaphragm-containing electrolysis section E2, will be described with reference to Fig. 3. Fig. 3 is a partial cross-sectional plan view taken along line III-III in Fig. 1. As an example, the case will be described in which the electrolytic cell-side anode 11, electrolytic cell-side cathode 12, and supply cell-side cathode 21 are rectangular and have a plate-like shape.

[0059] The electrolytic cell-side anode 11, electrolytic cell-side cathode 12, and supply cell-side cathode 21 are arranged such that the shorter side of the rectangle is aligned with the vertical direction (z-axis direction). This arrangement prevents bubbles generated by chemical reactions from adhering to both sides of the rectangle of each electrode. Furthermore, compared to when the longer side of the rectangle is aligned with the vertical direction (z-axis direction), when the shorter side is aligned with the vertical direction (z-axis direction), bubbles generated at the lower parts (negative side of the z-axis) of the electrolytic cell-side anode 11, electrolytic cell-side cathode 12, and supply cell-side cathode 21 are prevented from adhering to the upper parts (positive side of the z-axis) of the electrolytic cell-side anode 11, electrolytic cell-side cathode 12, and supply cell-side cathode 21.

[0060] The electrolytic cell-side anode 11, electrolytic cell-side cathode 12, and supply cell-side cathode 21 are arranged such that the longitudinal direction of the rectangles is along the horizontal direction (y-axis direction). In other words, the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 are arranged so that their rectangular flat surfaces (y-z planes) face each other with a predetermined distance between them. The predetermined distance is a distance appropriate for electrolysis performed using a pair of the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12. Similarly, the electrolytic cell-side anode 11 and the supply cell-side cathode 21 are arranged so that their rectangular flat surfaces (y-z planes) face each other with a predetermined distance between them. The predetermined distance is a distance appropriate for electrolysis performed using a pair of the electrolytic cell-side anode 11 and the supply cell-side cathode 21.

[0061] The electrolytic cell-side anode 11 comprises an electrolytic cell-side anode immersed portion 11a and an electrolytic cell-side anode protruding portion 11b. The electrolytic cell-side cathode 12 comprises an electrolytic cell-side cathode immersed portion 12a and an electrolytic cell-side cathode protruding portion 12b.

[0062] The electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 are inserted from the outside of the electrolytic cell 10 toward the inside. In FIG. 1 , as an example, the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 are inserted from the side of the electrolytic cell 10 (the xz plane side on the negative side of the y-axis) toward the horizontal direction (y-axis direction). The electrolytic cell-side anode immersion section 11a and the electrolytic cell-side cathode immersion section 12a inserted into the electrolytic cell 10 are positioned inside the electrolytic cell 10 and are entirely immersed in the first aqueous solution L1. In other words, the first aqueous solution L1 is stored in the electrolytic cell 10 so that the electrolytic cell-side anode immersion section 11a and the electrolytic cell-side cathode immersion section 12a are entirely immersed. That is, the first aqueous solution L1 is stored in the electrolytic cell 10 so that the liquid level S1 of the first aqueous solution L1 exceeds the upper ends (ends on the positive side of the z-axis) of the electrolytic cell side anode immersed portion 11a and the electrolytic cell side cathode immersed portion 12a.

[0063] The electrolytic cell-side anode projection 11b and the electrolytic cell-side cathode projection 12b are disposed on the exterior side of the electrolytic cell 10. The electrolytic cell-side anode projection 11b is electrically connected to a current control unit 40 via wiring 41, and the electrolytic cell-side cathode projection 12b is electrically connected to a current control unit 40 via wiring 42.

[0064] The supply tank side cathode 21 includes a supply tank side cathode immersed portion 21a and a supply tank side cathode protrusion portion 21b. The supply tank side cathode 21 is inserted from the outside of the electrolytic cell 10 toward the inside. In FIG. 1 , as an example, the supply tank side cathode 21 is inserted from the side of the electrolytic cell 10 (the xz plane side on the negative side of the y-axis) toward the horizontal direction (y-axis direction). The supply tank side cathode immersed portion 21a inserted into the supply tank 20 is disposed on the inside side of the supply tank 20 and is entirely immersed in the second aqueous solution L2. In other words, the second aqueous solution L2 is stored in the supply tank 20 such that the entire supply tank side cathode immersed portion 21a is immersed. That is, the second aqueous solution L2 is stored in the supply tank 20 such that the liquid level S2 of the second aqueous solution L2 exceeds the upper end (the end on the positive side of the z-axis) of the supply tank side cathode immersed portion 21a.

[0065] Supply tank side cathode projection 21b is disposed on the outer side of supply tank 20. Supply tank side cathode projection 21b is electrically connected to current control unit 40 via wiring 43.

[0066] The electrolytic cell side anode 11 and the feed cell side cathode 21 are each disposed in close proximity to the anion exchange membrane 30. In this specification, "close proximity" includes both a state in which the electrolytic cell side anode 11 and the feed cell side cathode 21 are close to the anion exchange membrane 30 with a predetermined gap between them, and a state in which the electrolytic cell side anode 11 and the feed cell side cathode 21 are in contact with the anion exchange membrane 30.

[0067] The plane of the rectangular plate on the anion exchange membrane 30 side of the electrolytic cell-side anode 11 (the yz plane on the positive x-axis side) is defined as plane P1. The plane of the rectangular plate on the anion exchange membrane 30 side of the supply cell-side cathode 21 (the yz plane on the negative x-axis side) is defined as plane P2. Planes P1 and P2 are arranged opposite each other with the anion exchange membrane 30 interposed between them. This arrangement allows a uniform electric field to be generated between the electrolytic cell-side anode 11 and the supply cell-side cathode 21.

[0068] The electrolytic cell-side anode 11 is disposed between the electrolytic cell-side cathode 12 and the anion exchange membrane 30. This arrangement makes it possible to maintain small potential differences between the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 and between the electrolytic cell-side anode 11 and the feed cell-side cathode 21.

[0069] Insoluble electrodes may be used as the electrolytic cell-side anode 11, the electrolytic cell-side cathode 12, and the supply cell-side cathode 21. More specifically, for example, a platinum-iridium-titanium electrode, a platinum electrode, a ruthenium-titanium electrode, or an iridium-titanium oxide electrode may be used.

[0070] The space purification device 1 according to this embodiment includes a diaphragm-less electrolysis unit E1 and a diaphragm-containing electrolysis unit E2. In Fig. 3, the diaphragm-less electrolysis unit E1 is shown as a part surrounded by a dashed-line rectangle, and the diaphragm-containing electrolysis unit E2 is shown as a part surrounded by a two-dot chain-line rectangle.

[0071] The diaphragm-less electrolysis unit E1 is provided in the electrolytic cell 10. The diaphragm-less electrolysis unit E1 produces hypochlorous acid by electrolyzing the first aqueous solution L1 without a diaphragm by passing a first current between the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12. In other words, the diaphragm-less electrolysis unit E1 includes the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12.

[0072] The membrane-equipped electrolysis unit E2 is provided across the electrolytic cell 10 and the supply cell 20. A second current is passed between the electrolytic cell-side anode 11 and the supply cell-side cathode 21, thereby performing membrane-equipped electrolysis via the anion exchange membrane 30. In other words, the membrane-equipped electrolysis unit E2 includes the electrolytic cell-side anode 11, the supply cell-side cathode 21, and the anion exchange membrane 30.

[0073] The current control unit 40 controls the first current flowing through the diaphragm-less electrolysis unit E1 and the second current flowing through the diaphragm-containing electrolysis unit E2, thereby controlling the chemical reactions occurring in the diaphragm-less electrolysis unit E1 and the chemical reactions occurring in the diaphragm-containing electrolysis unit E2.

[0074] 4, the chemical reactions occurring in the diaphragm-less electrolysis section E1 provided in the electrolytic cell 10 and the chemical reactions occurring in the diaphragm-containing electrolysis section E2 provided between the electrolytic cell 10 and the supply cell 20 will be described in detail below. The following describes a case where the first aqueous solution L1 containing chloride ions is a sodium chloride aqueous solution and the second aqueous solution L2 is a magnesium chloride aqueous solution.

[0075] [Diaphragmless electrolysis section E1 (electrolytic cell 10)] FIG. 4 is a list of reaction formulas occurring in the membraneless electrolysis section E1. Sodium chloride (NaCl) contained in the sodium chloride aqueous solution, which is the first aqueous solution L1, dissolves sodium ions in water. Na + ) and chloride ions (Cl - When a predetermined voltage is applied to the membraneless electrolysis section E1, a current flows, electrons move, and chemical reactions shown in reaction formulas (a) to (g) in FIG. 4 occur. Reaction formula (a) in Figure 4: Electrolyzer anode 11 (chlorine generation reaction) At the electrolytic cell side anode 11, chloride ions (Cl- ) is an electron (e - ) and chlorine (Cl2 (liquid, aq.)) is produced. Reaction formula (b) in Figure 4: Cathode 12 on the electrolytic cell side (hydrogen generation reaction) At the electrolytic cell-side cathode 12, water (H2O) in the first aqueous solution L1 converts electrons (e - ) and hydrogen (H2) and hydroxide ions (OH - ) occurs. Reaction formula (c) in Figure 4: Electrolyzer side anode 11 (oxygen generation reaction) At the electrolytic cell-side anode 11, electrons (e - ) is taken away, and oxygen (O2) and hydrogen ions (H + ) occurs. Reaction formula (d) in Figure 4: Hypochlorous acid generation reaction in the first aqueous solution L1 In the first aqueous solution L1 of the electrolytic cell 10, chlorine (Cl2) generated by reaction formula (a) in FIG. 4 undergoes a hydrolysis reaction with water (HO) in the first aqueous solution L1, generating hydrochloric acid (HCl) and hypochlorous acid (HClO). Hydrochloric acid (HCl) ionizes in the aqueous solution, generating hydrogen ions (H + ) and chloride ions (Cl - ) exists. (e) of Figure 4: Anion exchange membrane 30 When a voltage is applied to the membrane electrolysis unit E2 and a current flows, the first aqueous solution L1 stored in the electrolysis tank 10 generates electrons (e - ) and loses electrons (e - ) in the first aqueous solution L1, a force that maintains electrical neutrality acts, and negatively charged chloride ions (Cl - ) is supplied from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10 through the anion exchange membrane 30. In the first aqueous solution L1, the electrons (e - ) changes to chloride ions (Cl - ) can be said to be Reaction formula (f) in Figure 4: Hypochlorous acid generation reaction (equilibrium reaction formula) The equilibrium reaction formula for the hypochlorous acid generation reaction is shown below. -Depending on the increase or decrease of Cl in the electrolytic cell 10, the equilibrium state may shift to the right or to the left. - The current control described below is performed so that the apparent increase or decrease does not occur. Equation (g) in Figure 4: Chloride ion change during electrolysis Chlorine (Cl2) produced by reaction (a) in Figure 4 changes into hydrochloric acid (HCl) and hypochlorous acid (HClO) according to reaction (d) in Figure 4. This can be expressed in a single equation as equation (g) in Figure 4.

[0076] FIG. 5 shows reaction formulas that include the ratio of the current flowing through the diaphragm-less electrolysis unit E1 to the current flowing through the diaphragm-containing electrolysis unit E2. Here, the ratio of the current flowing through the electrolytic cell-side anode 11 that is used for the chlorine generation reaction of reaction formula (a) in FIG. 5 is denoted as "x," and the ratio of the current that is used for the oxygen generation reaction of reaction formula (c) in FIG. 5 is denoted as "1-x." Furthermore, the ratio of the current flowing through the electrolytic cell-side anode 11 that originates from the diaphragm-less electrolysis unit E1 is denoted as "y," and the ratio of the current that originates from the diaphragm-containing electrolysis unit E2 is denoted as "1-y." Applying the above x and y to reaction formula (b) + (c) + (g) in FIG. 5 and taking into account the change shown in (e) in FIG. 5, reaction formula (a) in FIG. 5 is obtained.

[0077] When membrane-less electrolysis is performed in the membrane-less electrolysis section E1, the chloride ions in the electrolytic cell 10 are consumed and therefore reduced, but in the space purification device 1 of this embodiment, chloride ions are supplied from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic cell 10.

[0078] Here, the amount of chloride ions (Cl ) consumed by the membraneless electrolysis is transferred from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10. - ) is supplied to the electrolytic cell 10, and chloride ions (Cl - ) does not appear to increase or decrease under the following conditions: In this reaction, hypochlorous acid (HClO) evaporates as a gas, so it is not shown in reaction formulas (b) to (g) in Figure 5. Reaction formula (b) in Figure 5: Cl - This shows the conditions under which the apparent increase or decrease does not occur. Equation (c) in Figure 5: This shows the conditional equation for the coefficients x and y, which is modified from reaction equation (b) in Figure 5. ·Reaction equation (d) in Figure 5: Substituting equation (c) in Figure 5 into reaction equation (a) in Figure 5 gives reaction equation (d) in Figure 5. Reaction equation (e) in Figure 5: This shows a modification of reaction equation (d) in Figure 5.

[0079] According to reaction formula (e) in Figure 5, for example, if two electrons flow into the diaphragm-less electrolysis unit E1, x units of hypochlorous acid (HClO) are generated. For example, if four electrons flow into the diaphragm-less electrolysis unit E1, 1-x units of oxygen are generated. For example, if two electrons flow into the diaphragm-less electrolysis unit E1, 1-x / 2 units of hydrogen are generated.

[0080] In addition, since the acid dissociation constant of hypochlorous acid (HClO) is approximately 7.5, it is necessary to maintain the pH of the first aqueous solution L1 unchanged. In reaction formula (e) of FIG. 5, hydroxide ions and hydrogen ions, which are the cause of the change in pH, react to form water and disappear from the reaction formula. Therefore, the amount of chloride ions (Cl ) consumed by the membraneless electrolysis is transferred from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10. - ) is supplied, and Cl is added to the electrolytic cell 10. - When the condition is such that there is no apparent increase or decrease in pH, the increase or decrease in pH can also be suppressed.

[0081] As described above, when the number of electrons flowing to the membraneless electrolysis section E1 changes, that is, when the ratio of the current flowing to the membraneless electrolysis section E1 and the current flowing to the membraneless electrolysis section E2 changes, the amount of chloride ions supplied from the supply tank 20 to the electrolytic cell 10 changes. For example, when the ratio of the current used for membraneless electrolysis changes, the amount of chloride ions (Cl - ) is supplied to the electrolytic cell 10. - When the current ratio is larger than the condition where the current does not increase or decrease (reaction formula (f) in FIG. 5), the Cl supplied from the supply tank 20 to the electrolytic tank 10 - The supply of Cl in the electrolytic cell 10 decreases. - decreases.

[0082] Cl in electrolytic cell 10- If the electrolysis without a diaphragm is continued in a state where the electrolysis efficiency is reduced, the Cl in the electrolytic cell 10 will gradually decrease. - increases, and Cl - reaches a level that does not appear to increase or decrease.

[0083] On the other hand, the amount of current used for membraneless electrolysis is such that chloride ions (Cl - ) is supplied to the electrolytic cell 10. - When the current amount is larger than the condition that the current amount does not increase or decrease (reaction formula (g) in Figure 5 below), the Cl supplied from the supply tank 20 to the electrolytic tank 10 - The supply of Cl in the electrolytic cell 10 increases. - increases.

[0084] The chloride ions (Cl - ) increases, the electrolysis efficiency of membrane-less electrolysis increases. If membrane-less electrolysis is continued in a state where the electrolysis efficiency has increased, the Cl in the electrolytic cell 10 gradually - decreases, and Cl - reaches a level that does not appear to increase or decrease.

[0085] In addition, Cl in the electrolytic cell 10 - When the amount of Cl in the electrolytic cell 10 increases, the equilibrium of reaction formula (f) in FIG. 5 shifts to the left, and the amount of chlorine generated increases. - By adjusting the current flowing through the membraneless electrolysis unit E1 and the current flowing through the membrane-containing electrolysis unit E2 so that the apparent change in the current does not increase or decrease, hypochlorous acid can be produced while suppressing the generation of chlorine.

[0086] [Diaphragm electrolysis part E2] FIG. 6 is a list of reaction formulas that occur in the electrolysis unit with a diaphragm E2. The reactions in the second aqueous solution L2 in the supply tank 20 will be described. The only electrode arranged in the supply tank 20 is the supply tank side cathode 21. When a predetermined voltage is applied to the electrolysis unit with a diaphragm E2, a current flows and electrons are The chemical reaction shown in Figure 6 occurs. Reaction formula (a) in Figure 6: Supply tank side cathode 21 (hydrogen generation reaction) At the supply tank side cathode 21, the water (H2O) of the second aqueous solution L2 is converted into electrons (e - ) and hydrogen (H2) and hydroxide ions (OH - ) is generated. The hydrogen evaporates as a gas, and the hydroxide ions are used in reaction (c) in Figure 6, which will be described later.

[0087] Figure 6(b): Anion exchange membrane 30 When a voltage is applied to the membrane electrolysis unit E2 and a current flows, chloride ions (Cl ) contained in the second aqueous solution L2 stored in the supply tank 20 are dissolved in the water. - ) passes through the anion exchange membrane 30 and is supplied to the first aqueous solution L1, and the second aqueous solution L2 passes through the supply tank side cathode 21 and receives electrons (e - In other words, in the second aqueous solution L2, the chloride ions (Cl - ) after the change, electrons (e - ) can be said to be

[0088] Reaction formula (c) in Figure 6: Second aqueous solution L2 (magnesium hydroxide precipitation reaction) The magnesium ions (Mg 2+ ) and hydroxide ions (OH - ) reacts with magnesium hydroxide (Mg(OH)2), which is a metal hydroxide precipitate, to form the precipitate. The solubility product of magnesium hydroxide (Mg(OH)2) is Ksp = 1.2 x 10 -11 (mol / L) 3 It is a substance that is extremely difficult to dissolve in aqueous solutions with a neutral to alkaline pH. For example, magnesium hydroxide, which can be dissolved in a weakly alkaline aqueous solution with a pH of 10, has a solubility of only 1.2 × 10 -3 In the second aqueous solution L2 of the supply tank 20, hydroxide ions (OH - ) is used to generate magnesium hydroxide precipitates, and hydroxide ions (OH - ) and the increase in pH of the second aqueous solution L2 can be suppressed.

[0089] Furthermore, when a magnesium chloride aqueous solution is used as the second aqueous solution L2, the pH of the magnesium hydroxide saturated aqueous solution produced after membrane electrolysis, in which magnesium hydroxide is saturated, is pH 10.36 as determined from the solubility product. Therefore, even after membrane electrolysis is performed over a long period of time, the pH of the second aqueous solution L2 can be maintained in a weakly alkaline state of up to 10.36 or less. In other words, when a magnesium chloride aqueous solution is used as the second aqueous solution L2, it is possible to prevent the second aqueous solution L2 from becoming strongly alkaline, with a pH of 11 or more. Therefore, it is possible to provide a space purification device 1 that is safer by preventing the second aqueous solution L2 stored in the supply tank 20 from becoming strongly alkaline after electrolysis.

[0090] Furthermore, for example, a contractor may install the space purification device 1 according to this embodiment. After use of the space purification device 1, the space purification device 1 may be overturned or dropped when the contractor removes the installed space purification device or during transportation after removal. Here, when a magnesium chloride aqueous solution is used as the second aqueous solution L2, the second aqueous solution L2 after the electrolysis reaction is a weakly alkaline magnesium hydroxide aqueous solution. Therefore, even if the second aqueous solution L2 leaks outside the space purification device 1 due to overturning or dropping, safety can be improved compared to space purification devices using a sodium chloride aqueous solution.

[0091] The above is a detailed description of the chemical reaction that occurs in the membraneless electrolysis section E1 provided in the electrolytic cell 10 and the chemical reaction that occurs in the membrane-containing electrolysis section E2 provided between the electrolytic cell 10 and the supply cell 20.

[0092] The current control unit 40 controls the chemical reaction. More specifically, the second current is controlled to replenish the chloride ions contained in the first aqueous solution L1 that have been reduced by the diaphragm-less electrolysis in the diaphragm-less electrolysis unit E1. By controlling the second current, chloride ions contained in the second aqueous solution L2 are permeated through the anion exchange membrane 30 and supplied to the first aqueous solution L1. Details will be described below with reference to FIG. 7.

[0093] 7 is a block diagram showing the current control unit 40 according to the embodiment. As shown in FIG. 7, the current control unit 40 includes a voltage acquisition unit 44, a calculation unit 45, and an estimation unit .

[0094] The voltage acquisition unit 44 acquires the voltage between the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12. The voltage acquisition unit 44 is, for example, a voltmeter. The calculation unit 45 calculates the conductivity of the first aqueous solution L1 based on the voltage acquired by the voltage acquisition unit 44. The estimation unit 46 estimates the chloride ion concentration of the first aqueous solution L1 based on the conductivity of the first aqueous solution L1 calculated by the calculation unit 45.

[0095] The current control unit 40 controls the first current passed through the membraneless electrolysis unit E1 and the second current passed through the membrane-containing electrolysis unit E2 shown in Fig. 7 so as to maintain the chloride ion concentration in the first aqueous solution L1 at a predetermined concentration. Three examples of current control by the current control unit 40 will be described below.

[0096] [1. When the first and second currents flow simultaneously] When the current control unit 40 simultaneously supplies the first current and the second current, it performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 46 is lower than a predetermined concentration: The current ratio between the first current and the second current is changed so as to increase the amount of chloride ions that permeate from the second aqueous solution L2 through the anion exchange membrane 30 and are supplied to the first aqueous solution L1. More specifically, the current ratio of the first current is decreased and the current ratio of the second current is increased. (2) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 46 is higher than a predetermined concentration: the current ratio between the first current and the second current is changed so as to reduce the amount of chloride ions that permeate from the second aqueous solution L2 through the anion exchange membrane 30 and are supplied to the first aqueous solution L1. More specifically, the current ratio of the first current is increased and the current ratio of the second current is decreased. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 46 is a predetermined concentration: the current ratio between the first current and the second current is not changed.

[0097] [2. When the first current flows at a predetermined value and the second current is controlled at the same time] When the current control unit 40 controls the second current while causing the first current to flow at a predetermined value, it performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 46 is lower than a predetermined concentration: A second current is passed so as to increase the amount of chloride ions that pass through the anion exchange membrane 30 from the second aqueous solution L2 and are supplied to the first aqueous solution L1. (2) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 46 is higher than a predetermined concentration: The second current is stopped so that the supply of chloride ions from the second aqueous solution L2 to the first aqueous solution L1 is stopped. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 46 is a predetermined concentration: the first current and the second current are not changed.

[0098] [3. When the first or second current flows] When the current control unit 40 causes the first current or the second current to flow, it performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 46 is lower than a predetermined concentration: The first current is stopped and the second current is simultaneously passed so as to increase the amount of chloride ions that pass through the anion exchange membrane 30 from the second aqueous solution L2 and are supplied to the first aqueous solution L1. (2) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 46 is higher than a predetermined concentration: The second current is stopped and the first current is simultaneously passed so as to stop the supply of chloride ions from the second aqueous solution L2 to the first aqueous solution L1. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 46 is a predetermined concentration: the first current and the second current are not changed.

[0099] As described above, the current control unit 40 controls the first current and the second current, so that the required amount of chloride ions can be supplied to the first aqueous solution L1 in the electrolytic cell 10, and the chloride ion concentration in the first aqueous solution L1 can be maintained at a predetermined concentration.

[0100] In the above-mentioned "1. When the first current and the second current are passed simultaneously," if there is an increase or decrease in the chloride ion concentration in the first aqueous solution L1, the current ratio between the first current and the second current is changed. Because the first current and the second current are passed simultaneously, the increase or decrease in the chloride ion concentration in the first aqueous solution L1 can be minimized, and the concentration can be maintained at an optimal predetermined level.

[0101] In the above-mentioned "2. When the first current is passed at a predetermined value while the second current is controlled simultaneously," the second current is mainly passed or stopped when the chloride ion concentration of the first aqueous solution L1 increases or decreases. In the "3. When the first current or the second current is passed," when the chloride ion concentration of the first aqueous solution L1 increases or decreases, one of the first current and the second current is passed and the other is stopped. Therefore, the chloride ion concentration of the first aqueous solution L1 can be maintained at a predetermined concentration. In the above-mentioned 2 and 3, it is only necessary to control either the first current or the second current, so current control is easy.

[0102] As described above, the chloride ions consumed by the first aqueous solution L1 can be appropriately supplied from the second aqueous solution L2, thereby providing the space purification device 1 capable of stably generating a desired amount of hypochlorous acid gas. Therefore, the space purification device 1 can be provided that can stably generate a desired amount of hypochlorous acid gas for a long period of time, such as one year, without supplying an aqueous solution containing chloride ions from the outside.

[0103] It is also possible to provide a plurality of current control units 40 and control the first current and the second current separately.

[0104] Next, a case will be described in which the yz plane on the positive side of the x-axis of the rectangular plate on the anion exchange membrane 30 side of the electrolytic cell-side anode 11 and the yz plane on the negative side of the x-axis of the rectangular plate on the anion exchange membrane 30 side of the supply cell-side cathode 21 do not face each other. When the planes of each rectangle are arranged parallel to the xy plane, a non-uniform electric field may be generated between the electrolytic cell-side anode 11 and the supply cell-side cathode 21. When a non-uniform electric field is generated between the electrolytic cell-side anode 11 and the supply cell-side cathode 21, the current distribution between the electrolytic cell-side anode 11 and the supply cell-side cathode 21 also becomes non-uniform.

[0105] When the current distribution between the electrolytic cell-side anode 11 and the supply cell-side cathode 21 becomes uneven, regions of high and low current density are generated. In the high current density areas, the catalytic layer on the surfaces of the electrolytic cell-side anode 11 and the supply cell-side cathode 21 (hereinafter referred to as each electrode) is more likely to deteriorate, while in the low current density areas, the catalytic layer on each electrode surface is less likely to deteriorate. In other words, when an uneven electric field occurs between the electrolytic cell-side anode 11 and the supply cell-side cathode 21, the current distribution becomes uneven, and regions of different current densities may exist simultaneously on the same electrode. Therefore, the catalytic layer may deteriorate unevenly due to the use of each electrode. If the degree of deterioration of the catalytic layer on the surface of each electrode differs, repeated electrolysis may result in the simultaneous existence of regions on each electrode that can be used as an electrode and regions that have deteriorated to the point where they become unusable. When electrolysis is performed using electrodes that include regions that cannot be used as electrodes, the electrolysis efficiency may be reduced.

[0106] In contrast, in the spatial purification device 1 according to this embodiment, the yz plane on the positive side of the x-axis and the yz plane on the negative side of the x-axis are arranged opposite each other via the anion exchange membrane 30. This arrangement allows a uniform electric field to be generated between the electrolytic cell-side anode 11 and the supply cell-side cathode 21, resulting in a uniform distribution of current between the two electrodes. This ensures that the deterioration of the catalytic layer on the surface of each electrode occurs uniformly, thereby preventing uneven deterioration of the catalytic layer on each electrode surface due to an uneven electric field, even when electrolysis is performed repeatedly. This prevents a decrease in electrolysis efficiency.

[0107] When membraneless electrolysis is performed in an electrolytic cell at room temperature and normal pressure, the electrolyte of the first aqueous solution L1 is not used in electrolysis, and oxygen and chlorine are mainly generated from the anode. It does not react with hypochlorous acid to reduce the concentration of hypochlorous acid, and it is a conductive electrolyte that is not reactive with the electrodes, the electrolytic cell, or the anion exchange membrane. More specifically, in addition to the above-described first aqueous solution L1, the electrolyte may be, for example, a metal chloride aqueous solution, a hydroxide salt aqueous solution, an acid salt aqueous solution, a phosphate aqueous solution, or a combination thereof. The metal chloride aqueous solution may be, for example, a dilute calcium chloride aqueous solution or a dilute magnesium chloride aqueous solution. The hydroxide salt aqueous solution may be, for example, a dilute sodium hydroxide aqueous solution or a dilute potassium hydroxide aqueous solution of 0.4 wt % (0.1 mol / L) or less. The acid salt aqueous solution may be, for example, a dilute hydrochloric acid aqueous solution of 0.4 wt % (0.1 mol / L) or less. The phosphate aqueous solution may be, for example, a disodium hydrogen phosphate aqueous solution, a sodium dihydrogen phosphate aqueous solution, a dipotassium hydrogen phosphate aqueous solution, or a potassium dihydrogen phosphate aqueous solution. As a specific example of a combination of the first aqueous solution L1, the pH may be adjusted by combining a dilute aqueous sodium chloride solution with a dilute aqueous sodium hydroxide solution.

[0108] As described above, the space purification device 1 according to the first embodiment can provide the following effects.

[0109] The space purification device 1 according to this embodiment includes an electrolytic cell 10 for storing a first aqueous solution L1 containing chloride ions, a supply tank 20 for storing a second aqueous solution L2 containing chloride ions at a higher concentration than the first aqueous solution L1 and supplying chloride ions to the first aqueous solution L1, an electrolytic cell-side anode 11 and an electrolytic cell-side cathode 12 provided in the electrolytic cell 10, a supply tank-side cathode 21 provided in the supply tank 20, and an anion coupler that connects the electrolytic cell 10 and the supply tank 20 to allow anions to pass therethrough based on a voltage applied between the electrolytic cell-side anode 11 and the supply tank-side cathode 21. The electrolytic cell comprises an ion exchange membrane 30, a diaphragm-less electrolysis unit E1 provided in the electrolytic cell 10 for generating hypochlorous acid by performing diaphragm-less electrolysis of a first aqueous solution L1 by passing a first current between the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12, a diaphragm-equipped electrolysis unit E2 provided between the electrolytic cell 10 and the supply cell 20 for performing diaphragm-equipped electrolysis via the anion exchange membrane 30 by passing a second current between the electrolytic cell-side anode 11 and the supply cell-side cathode 21, and a water recovery unit 14 for recovering water contained in the flowing air as a liquid and sending it to the electrolytic cell 10. Air introduced from an external space R into a supply cell-side internal space 23, which is the space above the liquid level S2 of the second aqueous solution L2 stored in the supply cell 20, flows sequentially through the electrolytic cell 10 and the water recovery unit 14 before being released into the external space R.

[0110] By having the above configuration, chloride ions are supplied from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10, thereby providing a space purification device 1 that can stably generate the desired amount of hypochlorous acid gas.

[0111] In addition, since air is introduced from the external space R into the supply tank side internal space 23, when the second aqueous solution L2 becomes excessive in volume, the air flows over the liquid surface S2 of the second aqueous solution L2, thereby promoting evaporation of the second aqueous solution L2.

[0112] Furthermore, the space purification device 1 according to this embodiment is configured so that air supplied to the electrolytic bath 10 from the supply tank-side internal space 23 is released into the first aqueous solution L1. Furthermore, the space purification device 1 according to this embodiment is configured so that air supplied to the electrolytic bath 10 from the external space R via the supply tank-side internal space 23 is released into the first aqueous solution L1 as bubbles B, the released bubbles B are mixed with hypochlorous acid, and the resulting mixed air M is released into the external space R.

[0113] By providing the above-mentioned configuration, the air supplied as bubbles B to the electrolytic cell 10 and the first aqueous solution The hypochlorous acid dissolved in the liquid L1 is mixed with the air and can be released into the external space R as mixed air M. In addition, the air supplied to the electrolytic cell 10 as bubbles B and released into the electrolytic cell-side internal space 23 is mixed with the hypochlorous acid gas volatilized from the second aqueous solution L2 into the electrolytic cell-side internal space 23, and can be released into the external space R as mixed air M. Thus, the desired amount of hypochlorous acid gas can be generated.

[0114] Furthermore, the space purification device 1 according to this embodiment is configured to stop supplying air to the supply tank 20 when the relative humidity of the external space R is lower than a predetermined humidity.

[0115] By providing the above configuration, excessive evaporation of the second aqueous solution L2 stored in the supply tank 20 can be suppressed.

[0116] In addition, the space purification device 1 of this embodiment is further provided with a lid portion 24 that is arranged at a predetermined position in the supply tank side internal space 23 within the supply tank 20 and has a predetermined opening 25, and the opening 25 of the lid portion 24 is configured so that the second aqueous solution L2 flows out to the upper surface side of the lid portion 24 when the liquid level of the second aqueous solution L2 rises due to purification operation.

[0117] When the liquid level S2 of the second aqueous solution L2 exceeds the lid part 24, the amount of the second aqueous solution L2 is excessive in the space purification device 1. Air supplied from the air supply part 22 flows over the liquid level S2 of the second aqueous solution L2 that has flowed out to the upper surface side of the lid part 24, promoting evaporation of the excess second aqueous solution L2. In this way, the lid part 24 with the opening 25 can suppress excessive evaporation of the second aqueous solution L2, while promoting evaporation of the excess second aqueous solution L2 that has flowed out to the upper surface side of the lid part 24 when the amount of the second aqueous solution L2 is excessive.

[0118] In addition, the space purification device 1 according to this embodiment is equipped with a current control unit that controls the second current so as to replenish the chloride ions contained in the first aqueous solution L1 that have been reduced by the diaphragm-less electrolysis, thereby causing the chloride ions contained in the second aqueous solution L2 to pass through the anion exchange membrane 30 and be supplied to the first aqueous solution L1.

[0119] With the above configuration, chloride ions reduced by electrolysis can be supplied from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10. Therefore, it is possible to provide the space purification device 1 that can stably generate a desired amount of hypochlorous acid gas for a long period of time without supplying an aqueous solution containing chloride ions from the outside.

[0120] <Embodiment 2> In the second embodiment, a description will be given of another configuration of the space purification device 1 according to the first embodiment. In the description of the second embodiment, the same components as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

[0121] FIG. 8 is a front cross-sectional view showing a space purification device 2 according to Embodiment 2. As shown in FIG. 8, the space purification device 2 according to this embodiment includes a second connection part 32 instead of the first connection part 31 included in the space purification device 1 according to Embodiment 1. The second connection part 32 is a tubular member that connects the electrolytic cell 10 and the supply cell 20. More specifically, one end (the negative side of the x-axis) of the second connection part 32 is connected to the supply cell-side internal space 23 of the supply cell 20, and the other end (the positive side of the x-axis) is connected to the electrolytic cell-side internal space 13 of the electrolytic cell 10. That is, unlike Embodiment 1, the air supplied from the external space R is supplied directly from the supply cell-side internal space 23 to the electrolytic cell-side internal space 13, and is not supplied to the first aqueous solution L1 stored in the electrolytic cell 10. That is, in this embodiment, the first aqueous solution L1 is not bubbled.

[0122] 8, the second connecting part 32 is a tubular member extending along the x-axis direction, and may be a cylindrical member or a rectangular tubular member. The second connecting part 32 is disposed above (on the positive side of the z-axis) the liquid level S1 of the first aqueous solution L1 stored in the electrolytic bath 10 and the liquid level S2 of the second aqueous solution L2 stored in the supply bath 20.

[0123] The first air flow path A1 is a flow path through which air introduced from the external space R flows through the supply tank 20 and is supplied to the electrolytic cell 10. The air flowing through the first air flow path A1 is indicated by outline arrows. More specifically, as shown in FIG. 8 , air introduced from the external space R into the supply tank-side internal space 23 via the air supply unit 22 is released into the electrolytic cell-side internal space 13 via the second connection unit 32. Air supplied from the external space R to the electrolytic cell-side internal space 13 via the supply tank-side internal space 23 is mixed with hypochlorous acid gas that has evaporated from the first aqueous solution L1 into the electrolytic cell-side internal space 13 and become gasified, resulting in mixed air. The mixed mixed air M is released into the external space R. The mixed air M contains moisture that has evaporated from the first aqueous solution L1 and the second aqueous solution L2. The moisture contained in the mixed air M is recovered by the water recovery unit 14 and returned to the first aqueous solution L1 as water droplets.

[0124] The space purification of the external space is performed by the mixed air containing hypochlorous acid that flows out from the outlet 15 into the space external to the space purification device 1. That is, the air containing hypochlorous acid removes bacteria, fungi, viruses, odors, and the like contained in the air in the space external to the housing C.

[0125] In the present embodiment as well, when the relative humidity of the air in the external space R is less than a predetermined humidity, the supply of air by the air supply unit 22 to the supply tank-side internal space 23 is stopped. The "predetermined humidity" refers to when the relative humidity of the air in the external space R is less than 35%. By stopping the supply of air by the air supply unit 22 to the supply tank-side internal space 23 when the relative humidity of the air in the external space R is less than the predetermined humidity, excessive evaporation of the second aqueous solution L2 stored in the supply tank 20 can be suppressed.

[0126] In this embodiment, the space purification device 1 does not include the first connection unit 31 included in the space purification device 1 described in Embodiment 1, and air circulating through the supply tank 20 is not bubbled into the first aqueous solution L1. However, the electrolytic cell 10 may be provided with a separate air supply unit. More specifically, an air supply unit (not shown) capable of supplying air from the external space R to the first aqueous solution L1 may be provided below the liquid level S1 of the first aqueous solution L1 in the electrolytic cell 10, thereby bubbling the first aqueous solution L1. The air supply unit may be, for example, a blower. In other words, air directly introduced from the external space R into the first aqueous solution L1 via the air supply unit may be bubbled through the first aqueous solution L1 to generate bubbles B, which may then be brought into gas-liquid contact with the hypochlorous acid contained in the first aqueous solution L1 and released as mixed air M from the electrolytic cell 10 into the external space R.

[0127] As described above, the space purification device 2 according to the second embodiment can provide the following effects.

[0128] In the space purification device 2 of this embodiment, the air supplied from the supply tank side internal space 23 to the electrolytic tank 10 is configured to be released into the electrolytic tank side internal space 13, which is the space above the liquid level S1 of the first aqueous solution L1 stored in the electrolytic tank 10.

[0129] By having the above configuration, chloride ions are supplied from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10, thereby providing a space purification device 2 that can stably generate the desired amount of hypochlorous acid gas.

[0130] In the space purification device 2 according to the present embodiment, the air is circulated from the external space R to the supply tank side internal space 23 The air supplied to the electrolytic cell side internal space 13 via the filter 14 is mixed with the volatilized hypochlorous acid, and the mixed air M is released into the external space R.

[0131] By having the above configuration, chloride ions are supplied from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10, thereby providing a space purification device 2 that can stably generate the desired amount of hypochlorous acid gas.

[0132] Furthermore, in the space purification device 2 according to this embodiment, when the relative humidity of the external space R is lower than a predetermined humidity, the supply of air to the supply tank 20 is stopped.

[0133] By providing the above configuration, when the relative humidity of the air in the external space R is below a predetermined humidity, the supply of air to the supply tank side internal space 23 by the air supply unit 22 is stopped, thereby suppressing excessive evaporation of the second aqueous solution L2 stored in the supply tank 20.

[0134] <Third Embodiment> In the third embodiment, a description will be given of another configuration of the space purification device 1 according to the first embodiment. In the description of the third embodiment, the same components as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

[0135] FIG. 9 is a front cross-sectional view showing a space purification device according to Embodiment 3. As shown in FIG. 9, the space purification device 3 according to this embodiment includes a third connector 33 in addition to the first connector 31 included in the space purification device 1 according to Embodiment 1. The third connector 33 is a tubular member that connects the external space R and the electrolytic bath 10. More specifically, one end (the negative side of the x-axis) of the third connector 33 is connected to the air supply unit 22. The other end (the positive side of the x-axis) of the third connector 33 is connected to the first connector 31 or the electrolytic bath 10 at a position below the liquid level of the first aqueous solution L1 stored in the electrolytic bath 10. As an example, FIG. 9 shows a state in which the end of the third connector 33 on the positive side of the x-axis is connected to the first connector 31.

[0136] In other words, the space purification device 3 according to this embodiment includes a first air flow path A1, which is a flow path through which air introduced from the external space R flows through the supply tank 20 and is supplied to the electrolytic cell 10, and a second air flow path A2, which is a flow path through which air introduced from the external space R is supplied to the electrolytic cell 10 without passing through the supply tank 20. In FIG. 9 , the air flowing through the first air flow path A1 is indicated by a hollow arrow, and the air flowing through the second air flow path A2 is indicated by a hollow arrow with a dashed line. The second air flow path A2 is a series of paths through which air supplied from the external space R to the space purification device 3 flows through the device and is released to the external space R as mixed air M containing hypochlorous acid. That is, the second air flow path A2 indicates the flow of air from the external space R, through the air supply unit 22, the third connection unit 33, the first aqueous solution L1, the electrolytic cell-side internal space 13, the water recovery unit 14, the discharge port 15, and to the external space R.

[0137] More specifically, in the first air flow path A1, as in the first embodiment, air introduced from the external space R into the supply tank-side internal space 23 via the air supply unit 22 is released as bubbles B into the first aqueous solution L1 stored in the electrolytic cell 10 via the first connecting unit 31. In other words, bubbles B are generated by bubbling the first aqueous solution L1 with the air introduced from the external space R. In the second air flow path A2, when the end of the third connecting unit 33 on the positive side of the x-axis is connected to the first connecting unit 31, air introduced from the external space R into the third connecting unit 33 via the air supply unit 22 is mixed with air that has circulated through the supply tank-side internal space 23 inside the first connecting unit 31 and is released as bubbles B into the first aqueous solution L1. When the end of the third connecting part 33 on the positive side of the x-axis is connected to the electrolytic cell 10 at a position below the liquid level of the first aqueous solution L1 stored in the electrolytic cell 10, air introduced from the external space R into the third connecting part 33 via the air supply part 22 is released into the first aqueous solution L1 as bubbles B in the second air flow path A2. In other words, bubbles B are generated by bubbling the first aqueous solution L1 with the air introduced from the external space R.

[0138] In this embodiment, the first air flow path A1 and the second air flow path A2 are switched depending on the relative humidity of the air introduced from the external space R into the space purification device 3. A flow path switching mechanism (not shown), such as a damper or a valve, may be provided at the switching point between the first air flow path A1 and the second air flow path A2. More specifically, when the relative humidity of the external space R is equal to or higher than a predetermined humidity, the air supply unit 22 switches between the first air flow path A1 and the second air flow path A2 so as to supply air to the first air flow path A1, and when the relative humidity of the external space R is lower than the predetermined humidity, the air supply unit 22 switches between the first air flow path A1 and the second air flow path A2.

[0139] When the second aqueous solution L2 is an aqueous magnesium chloride solution, the "predetermined humidity" refers to the relative humidity of the air in the external space R being less than 35%, for example. When the relative humidity of the air in the external space R is less than the predetermined humidity, the air supply unit 22 stops supplying air to the first air flow path A1 and starts supplying air to the second air flow path A2. That is, when the relative humidity of the air in the external space R is less than the predetermined humidity, the air flow path is switched from the first air flow path A1 to the second air flow path A2. When the relative humidity of the air in the external space R becomes equal to or greater than the predetermined humidity, the air flow path is switched from the second air flow path A2 to the first air flow path A1. This makes it possible to continue supplying air to the first aqueous solution L1 via the second air flow path A2 while suppressing excessive evaporation of the second aqueous solution L2 stored in the supply tank 20, even when the relative humidity of the external space R is less than the predetermined humidity. In the space purification device 3 of this embodiment, even if the relative humidity of the external space R is below a predetermined humidity, the supply of air to the first aqueous solution L1 can be continued, thereby allowing purification operation to be performed without reducing the amount of mixed air M generated.

[0140] As described above, the space purification device 3 according to the third embodiment can provide the following effects.

[0141] The space purification device 3 according to this embodiment includes a first air flow path A1 through which air introduced from the external space R flows through the supply tank 20 and is supplied to the electrolytic cell 10, and a second air flow path A2 through which air introduced from the external space R is supplied to the electrolytic cell 10 without flowing through the supply tank 20. The first air flow path A1 and the second air flow path A2 are switched depending on the relative humidity of the air introduced from the external space R.

[0142] In addition, the space purification device 3 of this embodiment switches between the first air flow path A1 and the second air flow path A2 so as to supply air to the first air flow path A1 when the relative humidity of the external space R is below a predetermined humidity, and to supply air to the second air flow path A2 when the relative humidity of the external space R is equal to or higher than the predetermined humidity.

[0143] With the above configuration, even when the relative humidity of the external space R is below a predetermined humidity, the supply of air to the first aqueous solution L1 through the second air flow path A2 can be continued while suppressing excessive evaporation of the second aqueous solution L2 stored in the supply tank 20. In the space purification device 3 according to this embodiment, the supply of air to the first aqueous solution L1 can be continued even when the relative humidity of the external space R is below a predetermined humidity, so that the purification operation can be performed without reducing the amount of mixed air M containing hypochlorous acid generated. Therefore, a space purification device 3 can be provided that can stably generate a desired amount of hypochlorous acid gas for a long period of time without supplying an aqueous solution containing chloride ions from the outside.

[0144] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention.

[0145] An outline of one aspect of the present disclosure is as follows.

[0146] (Item 1) an electrolytic cell (10) for storing a first aqueous solution (L1) containing chloride ions; a supply tank (20) for storing a second aqueous solution (L2) containing chloride ions at a higher concentration than that of the first aqueous solution (L1) and supplying chloride ions to the first aqueous solution (L1); an electrolytic cell-side anode (11) and an electrolytic cell-side cathode (12) provided in the electrolytic cell (10); a supply tank-side cathode (21) provided in the supply tank (20); an anion exchange membrane (30) connecting the electrolytic cell (10) and the supply cell (20) so as to be permeable to anions based on a voltage applied between the electrolytic cell-side anode (11) and the supply cell-side cathode (21); a membrane-less electrolysis unit (E1) provided in the electrolytic cell (10) for generating hypochlorous acid by membrane-less electrolysis of the first aqueous solution (L1) by passing a first current between the electrolytic cell-side anode (11) and the electrolytic cell-side cathode (12); a membrane-type electrolysis section (E2) provided between the electrolytic cell (10) and the supply cell (20), which performs membrane-type electrolysis via the anion exchange membrane (30) by passing a second current between the electrolytic cell-side anode (11) and the supply cell-side cathode (21); a water recovery section (14) that recovers moisture contained in the flowing air as a liquid and transfers it to the electrolytic cell (10); Equipped with The air introduced from the external space (R) into a supply tank-side internal space (23), which is a space above the liquid level (S2) of the second aqueous solution (L2) stored in the supply tank (20), flows through the electrolytic tank (10) and the water recovery unit (14) in this order, and is then released into the external space (R). Space purification device. (Item 2) The air supplied from the supply tank side internal space (23) to the electrolytic tank (10) is discharged into the first aqueous solution (L1). The space purification device (1) according to item 1. (Item 3) The air supplied to the electrolytic cell (10) is released as bubbles (B) into the first aqueous solution (L1), the released bubbles (B) are mixed with the hypochlorous acid, and the mixed air (M) is released into the external space (R). Item 2. The space purification device (1). (Item 4) The air supplied from the supply tank-side internal space (23) to the electrolytic tank (10) is discharged into an electrolytic tank-side internal space (13), which is a space above a liquid level (S1) of the first aqueous solution (L1) stored in the electrolytic tank (10). The space purification device (2) according to item 1. (Item 5) The air supplied from the external space (R) to the electrolytic cell side internal space (13) through the supply cell side internal space (23) is mixed with the volatilized hypochlorous acid, and the mixed air (M) is released into the external space (R). Item 4. The space purification device (2). (Item 6) 6. The space purification device according to item 3 or 5, wherein the supply of the air to the supply tank (20) is stopped when the relative humidity of the external space (R) is lower than a predetermined humidity. (Item 7) a first air flow path (A1) through which air introduced from the external space (R) flows through the supply tank (20) and is supplied to the electrolytic tank (10); a second air flow path (A2) through which air introduced from the external space (R) is supplied to the electrolytic cell (10) without passing through the supply cell (20); Equipped with switching between the first air flow path (A1) and the second air flow path (A2) depending on the relative humidity of the air introduced from the external space (R); The space purification device (3) according to item 1. (Item 8) When the relative humidity of the external space (R) is lower than a predetermined humidity, the air is supplied to the first air flow path (A1); When the relative humidity of the external space (R) is equal to or higher than a predetermined humidity, the first air flow path (A1) and the second air flow path (A2) are switched so as to supply the air to the second air flow path (A2). Item 7. The space purification device (3) according to item 7. (Item 9) The supply tank (20) further includes a lid (24) disposed at a predetermined position in the supply tank-side internal space (23) and having a predetermined opening (25), the opening (25) of the lid (24) is configured so that the second aqueous solution (L2) flows out to an upper surface side of the lid (24) when the liquid level (S2) of the second aqueous solution (L2) rises due to a purification operation. Item 1. The space purification device according to item 1. (Item 10) a current control unit (40) that controls the second current so as to compensate for chloride ions contained in the first aqueous solution (L1) that have decreased due to the membrane-less electrolysis, thereby causing chloride ions contained in the second aqueous solution (L2) to permeate through the anion exchange membrane (30) and supply them to the first aqueous solution (L1); Item 1. The space purification device according to item 1. [Explanation of symbols]

[0147] 1. Space Purification Device 2. Space Purification Device 3. Space Purification Device 10 electrolyzer 11 Electrolyzer side anode 11a Electrolytic tank side anode immersion part 11b Electrolytic tank side anode protrusion 12 Electrolytic cell side cathode 12a Electrolytic cell side cathode immersion section 12b Electrolytic cell side cathode protrusion 13 Internal space on electrolytic cell side 14 Water recovery section 15 Outlet 16 Water level detector 20 Supply tank 21 Supply tank side cathode 21a Supply tank side cathode immersion section 21b Supply tank side cathode protrusion 22 Air supply section 23 Supply tank side internal space 24 Lid 25 Opening 30 Anion exchange membrane 31 1st connection part 32 2nd connection part 33 Third connection part 40 Current control section 41 Wiring 42 Wiring 43 Wiring 44 Voltage acquisition unit 45 Calculation section 46 Estimation part A1 First air flow path A2 Second air flow path B. Air bubbles C chassis E1 Diaphragmless electrolytic section E2 Diaphragm electrolysis section L1 1st aqueous solution L2 2nd aqueous solution M mixed air R External space S1 liquid level S2 liquid level W1 W2 pieces W3 pieces W4 pieces

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 at a higher concentration than the first aqueous solution and supplying chloride ions to the first aqueous solution; an electrolytic cell-side anode and an electrolytic cell-side cathode provided in the electrolytic cell; a supply tank-side cathode provided in the supply tank; an anion exchange membrane connecting the electrolytic cell and the supply cell so as to be permeable to anions based on a voltage applied between the electrolytic cell-side anode and the supply cell-side cathode; a membrane-less electrolysis unit provided in the electrolytic cell that generates hypochlorous acid by performing membrane-less electrolysis of the first aqueous solution by passing a first current between the electrolytic cell-side anode and the electrolytic cell-side cathode; a membrane-with-diaphragm electrolysis section provided across the electrolytic cell and the supply cell, which performs membrane-with-diaphragm electrolysis via the anion exchange membrane by passing a second current between the electrolytic cell-side anode and the supply cell-side cathode; a water recovery unit that recovers moisture contained in the circulating air as liquid and transfers it to the electrolytic cell; Equipped with air introduced from an external space into a supply tank-side internal space, which is a space above the liquid level of the second aqueous solution stored in the supply tank, flows through the electrolytic tank and the water recovery unit in this order, and is released into the external space; Space purification device.

2. The air supplied from the supply tank side internal space to the electrolytic tank is released into the first aqueous solution. The space purification device according to claim 1 .

3. The air supplied to the electrolytic cell is released as bubbles into the first aqueous solution, the released bubbles are mixed with the hypochlorous acid, and the mixed air is released into the external space. The space purification device according to claim 2 .

4. the air supplied from the supply tank-side internal space to the electrolytic tank is released into the electrolytic tank-side internal space, which is a space above the liquid surface of the first aqueous solution stored in the electrolytic tank. The space purification device according to claim 1 .

5. The air supplied from the external space to the electrolytic cell-side internal space through the supply cell-side internal space is mixed with the volatilized hypochlorous acid, and the mixed air is released into the external space. The space purification device according to claim 4.

6. The space purification device according to claim 3 or 5, wherein the supply of the air to the supply tank is stopped when the relative humidity of the external space is lower than a predetermined humidity.

7. a first air flow path through which air introduced from the external space flows through the supply tank and is supplied to the electrolytic tank; a second air flow path through which air introduced from the external space is supplied to the electrolytic cell without passing through the supply cell; Equipped with The first air flow path and the second air flow path are connected in accordance with the relative humidity of the air introduced from the external space. Switching the air flow path The space purification device according to claim 1 .

8. When the relative humidity of the external space is lower than a predetermined humidity, the air is supplied to the first air flow path; When the relative humidity of the external space is equal to or higher than a predetermined humidity, the first air flow path and the second air flow path are switched so as to supply the air to the second air flow path. The space purification device according to claim 7.

9. a lid portion disposed at a predetermined position in the supply tank-side internal space within the supply tank and having a predetermined opening; the opening of the lid portion is configured to allow the second aqueous solution to flow out to an upper surface side of the lid portion when the liquid level of the second aqueous solution rises due to a purification operation. The space purification device according to claim 1 .

10. a current control unit that controls the second current so as to compensate for chloride ions contained in the first aqueous solution that have been reduced by the membrane-less electrolysis, thereby causing chloride ions contained in the second aqueous solution to permeate through the anion exchange membrane and supply them to the first aqueous solution. The space purification device according to claim 1 .

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