Space purifier

Abstract

To provide a space purifier stably generating a desired amount of a hypochlorous acid gas without supplying a water solution containing chloride ions from outside for a long period of time.SOLUTION: A space purifier 1 includes: a chloride tank 10 permeating chloride ions included in a first water solution L1 through a first anionic exchange membrane 43 by a first diaphragm electrolysis to supply them to a second water solution L2; a chlorine tank 20 generating chlorine by subjecting a second water solution L2 to the first diaphragm electrolysis and a second diaphragm electrolysis; and a hypochlorous acid tank 30 generating hypochlorous acid by reacting chlorine supplied from the chlorine tank 20 and water included in a third water solution L3 to generate hypochlorous acid, and permeating the chloride ions included in the third water solution L3 through the second anionic exchange membrane 44 by the second diaphragm electrolysis to supply the chloride ions to the second water solution. A purification operation where the air introduced from an outside space R is passed through the chlorine tank 20 and the hypochlorous acid tank 30 and is discharged to the outside space R together with the hypochlorous acid, is performed.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 removes bacteria, fungi, viruses, odors, and the like from the air using hypochlorous acid generated by electrolyzing an aqueous sodium chloride solution. [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 space purification device of the present invention includes a chloride tank that stores a first aqueous solution containing chloride ions and supplies the chloride ions contained in the first aqueous solution to a second aqueous solution by passing them through a first anion exchange membrane through a first diaphragm electrolysis, a chlorine tank that stores a second aqueous solution containing chloride ions and generates chlorine by first and second diaphragm electrolysis of the second aqueous solution, and a hypochlorous acid tank that stores a third aqueous solution containing chloride ions and generates hypochlorous acid by reacting chlorine supplied from the chlorine tank with water contained in the third aqueous solution and supplies the chloride ions contained in the third aqueous solution to the second aqueous solution by passing them through a second anion exchange membrane through a second diaphragm electrolysis, and performs a purification operation in which air introduced from an external space flows through the chlorine tank and the hypochlorous acid tank and is released into the external space together with hypochlorous acid. [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] Figure 3 shows a list of chemical reaction formulas that occur in the first membrane electrolysis section. [Figure 4] Figure 4 shows a list of chemical reaction formulas that occur in the second membrane electrolysis section. 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. In the space purifying device 1, a chlorine tank 20 (described later) generates chlorine, and the chlorine is dissolved in a third aqueous solution L3 stored in a hypochlorous acid tank 30 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 discharging the volatilized hypochlorous acid into the external space of the 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] 1, the space purification device 1 includes a housing C, a chloride tank 10, a chlorine tank 20, a hypochlorous acid tank 30, a first connection part 41, a second connection part 42, a first anion exchange membrane 43, a second anion exchange membrane 44, and a current control part 50. The space purification device 1 performs a purification operation in which air introduced from the external space R flows through the chloride tank 10, the chlorine tank 20, and the hypochlorous acid tank 30 and is released into the external space R together with hypochlorous acid.

[0013] The housing C houses the chloride tank 10, the chlorine tank 20, the hypochlorous acid tank 30, the first connecting part 41, the second connecting part 42, the first anion exchange membrane 43, the second anion exchange membrane 44, and the current control unit 50. 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 8 hours every day for one year, the volumes of the chloride tank 10, the chlorine tank 20, and the hypochlorous acid tank 30 are preferably set, for example, such that the volume of the chloride tank 10 is at least about 12 times the volume of the chlorine tank 20. By setting such a volume ratio, the chloride tank 10 can store the first aqueous solution L1 containing a sufficient amount of chloride ions required to be supplied to the chlorine tank 20. Therefore, chloride ions can be stably supplied from the first aqueous solution L1 stored in the chloride tank 10 to the second aqueous solution L2 stored in the chlorine tank 20. The amount of the first aqueous solution L1 stored in the chlorine tank 20 is, for example, about 2 mL to 10 mL.

[0015] The chloride tank 10, the chlorine tank 20, and the hypochlorous acid tank 30 are arranged in this order from the negative side of the x-axis when viewed from the front. A first anion exchange membrane 43 is arranged between the chloride tank 10 and the chlorine tank 20. A second anion exchange membrane 44 is arranged between the chlorine tank 20 and the hypochlorous acid tank 30. For example, if the surfaces where the chloride tank 10 and the chlorine tank 20 face each other are formed with a frame-shaped member, the first anion exchange membrane 43 may be arranged so as to be fitted into the frame-shaped member. Similarly, if the surfaces where the chlorine tank 20 and the hypochlorous acid tank 30 face each other are formed with a frame-shaped member, the second anion exchange membrane 44 may be arranged so as to be fitted into the frame-shaped member. The current control unit 50 is arranged at any position within the housing C.

[0016] The chloride tank 10 stores a first aqueous solution L1 containing chloride ions, and is used for the first membrane electrolysis. Therefore, this is a tank for supplying chloride ions contained in the first aqueous solution L1 to the second aqueous solution L2 stored in the chlorine tank 20 by passing them through the first anion exchange membrane 43.

[0017] FIG. 1 shows a state in which a first aqueous solution L1 is stored in a chloride tank 10. The first aqueous solution L1 is a metal chloride aqueous solution containing metal ions and chloride ions. By first membrane electrolysis (described later), chloride ions contained in the first aqueous solution L1 are passed through a first anion exchange membrane 43 and supplied to a second aqueous solution L2 stored in a chlorine tank 20. Furthermore, by performing first membrane electrolysis on the first aqueous solution L1, metal ions contained in the first aqueous solution L1 react with hydroxide ions generated by the first membrane electrolysis to form a metal hydroxide precipitate. Preferably, the first aqueous solution L1 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 first aqueous solution L1, the mass percent concentration of the magnesium chloride aqueous solution is, for example, 1% to 35%. For example, when the first aqueous solution L1 is a magnesium chloride aqueous solution, by performing the first membrane electrolysis described below, magnesium ions contained in the magnesium chloride aqueous solution react with hydroxide ions generated by the first membrane electrolysis to form a precipitate of magnesium hydroxide. The "precipitate" of magnesium hydroxide includes those in the form of hard sand, colloid, slurry, or gel, and also includes a state in which the aqueous solution is cloudy.

[0018] The chloride tank 10 includes a chloride tank-side cathode 11, an air supply unit 12, and a chloride tank-side internal space 13. The chloride tank 10 may further include a lid unit 14.

[0019] The chloride tank-side cathode 11 is paired with a chlorine tank-side anode 21 (described later) via a first anion exchange membrane 43 and is used for the first membrane-with-diaphragm electrolysis of the first aqueous solution L1. The details of the first membrane-with-diaphragm electrolysis will be described later. By the first membrane-with-diaphragm electrolysis of the first aqueous solution L1 performed using the pair of the chloride tank-side cathode 11 and the chlorine tank-side anode 21, chloride ions are supplied from the first aqueous solution L1 to the second aqueous solution L2 via the first anion exchange membrane 43.

[0020] The chloride tank side cathode 11 is inserted from the outside to the inside of the chloride tank. The chloride tank side cathode 11 has a plate-like shape. The plate-like shape includes a rectangular shape and a rectangular shape. An insoluble electrode may be used as the chloride tank side cathode 11. 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.

[0021] The first anion exchange membrane 43 is a membrane-like member that connects the chloride tank 10 and the chlorine tank 20 in a manner that allows anions to pass therethrough, based on a voltage applied between the chloride tank 10 and the chlorine tank 20. More specifically, when a voltage is applied between the chloride tank-side cathode 11 and the chlorine tank-side anode 21, first membrane-with-diaphragm electrolysis is performed via the first anion exchange membrane 43. By the first membrane-with-diaphragm electrolysis using the chloride tank-side cathode 11 and the chlorine tank-side anode 21, chloride ions contained in the first aqueous solution L1 permeate the first anion exchange membrane 43 and are supplied to the second aqueous solution L2 (positive direction of the x-axis, indicated by a thick black arrow).

[0022] The first anion exchange membrane 43 in this embodiment is not a type of anion exchange membrane through which anions permeate due to osmotic pressure without using electricity. More specifically, when chloride ions contained in the first aqueous solution L1 permeate the first anion exchange membrane 43 and are supplied to the second aqueous solution L2 by first membrane-with-diaphragm electrolysis using the chloride tank-side cathode 11 and the chlorine tank-side anode 21, magnesium ions, which are cations contained in the first aqueous solution L1, do not permeate the first anion exchange membrane 43. The first anion exchange membrane 43 is, for example, a hydrocarbon-based anion exchange membrane, and includes membranes that have monovalent anion-selective permeability, alkali resistance, and high-temperature resistance.

[0023] The plane of the first anion exchange membrane 43 side of the chloride tank side cathode 11 (yz plane on the x-axis positive side) and the salt The element tank-side anode 21 is arranged so that its plane on the first anion exchange membrane 43 side (yz plane on the negative x-axis side) faces each other. This arrangement allows a uniform electric field to be generated between the chloride tank-side cathode 11 and the chlorine tank-side anode 21. Since electrolysis is generated uniformly, the current between the two electrodes is also distributed uniformly. Therefore, deterioration of the catalytic layer on the surface of each electrode occurs uniformly, and uneven deterioration of the catalytic layer on the surface of each electrode due to an uneven electric field can be suppressed even when electrolysis is performed repeatedly. Therefore, a decrease in electrolysis efficiency can be suppressed.

[0024] The chloride tank side cathode 11 and the chlorine tank side anode 21 are disposed close to the first anion exchange membrane 43. In this specification, "close" refers to a state in which the chloride tank side cathode 11 and the chlorine tank side anode 21 are close to the first anion exchange membrane 43 with a predetermined gap therebetween.

[0025] The air supply unit 12 is a blower or a predetermined opening that introduces air from the external space R into the chloride tank 10. More specifically, the air supply unit 12 introduces the air from the external space R into a chloride tank-side internal space 13, which will be described later. The air supply unit 12 is disposed above the liquid level S1 of the first aqueous solution L1 in the chloride tank 10. The air introduced from the air supply unit 12 into the chloride tank-side internal space 13 is introduced into the chlorine tank 20 via a first connection unit 41, which will be described later.

[0026] When the relative humidity of the air in the external space R is less than a predetermined humidity, the air supply unit 12 stops supplying air to the chloride tank-side internal space 13. When the first aqueous solution L1 stored in the chloride tank 10 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. By stopping the supply of air by the air supply unit 12 to the chloride tank-side internal space 13 when the relative humidity of the air in the external space R is less than the predetermined humidity, excessive evaporation of the first aqueous solution L1 stored in the chloride tank 10 can be suppressed. Furthermore, by stopping the supply of air by the air supply unit 12 to the chloride tank-side internal space 13 when the relative humidity of the air in the external space R is less than 35%, precipitation of magnesium chloride can be suppressed.

[0027] If the air supply unit 12 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 12 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.

[0028] The chloride tank-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 chloride tank 10. In other words, the first aqueous solution L1 does not reach the internal upper surface of the chloride tank 10 (xy plane on the positive z-axis side), and the chloride tank 10 has the chloride tank-side internal space 13. Air is supplied from an air supply unit 12 to the chloride tank-side internal space 13.

[0029] Here, the purification operation of the space purification device 1 may cause the liquid level S1 of the first aqueous solution L1 to rise and exceed a predetermined position (height in the z-axis direction) of the chloride tank 10. The purification operation refers to the process in which air introduced from the external space R by the space purification device 1 flows through the chlorine tank 20 and the hypochlorous acid tank 30 and is released into the external space together with hypochlorous acid. Examples of "cases in which the liquid level S1 of the first aqueous solution L1 rises due to the purification operation of the space purification device 1" include cases in which water permeates the first anion exchange membrane 43 from the second aqueous solution L2 to the first aqueous solution L1 due to a concentration difference between the first aqueous solution L1 and the second aqueous solution L2 (described later), and cases in which the first aqueous solution L1 absorbs moisture contained in the air supplied from the external space R when the first aqueous solution L1 is a magnesium chloride aqueous solution.

[0030] The state in which the liquid level S1 of the first aqueous solution L1 exceeds a predetermined position in the chloride tank 10 is the space purification state. This is a state in which the amount of the first aqueous solution L1 in the apparatus 1 has unintentionally increased, resulting in an excess amount of the first aqueous solution L1. The air supplied from the air supply unit 12 to the chloride tank-side internal space 13 flows over the liquid level S1 of the first aqueous solution L1, thereby promoting evaporation of the first aqueous solution L1. In this way, when the amount of the first aqueous solution L1 becomes excessive, the air supplied by the air supply unit 12 and flowing through the chloride tank-side internal space 13 can promote evaporation of the excess first aqueous solution L1.

[0031] The lid 14 has a predetermined opening 15 and is a plate-like member extending, for example, along the xy plane. The lid 14 is, for example, a solid member molded from a resin material that is insoluble in the first aqueous solution L1, or a membrane-like member such as a silicone membrane that allows passage of air bubbles that may be generated from the first aqueous solution L1. The end of the lid 14 on the negative x-axis is connected to the inner wall surface of the chloride tank 10, but the end on the positive x-axis is not connected to the inner wall surface of the chloride tank 10. The lid 14 is disposed at a predetermined position in the chloride tank-side internal space 13. The "predetermined position" where the lid 14 is disposed refers to a position above the liquid level S1 of the first aqueous solution L1 when the space purification device 1 starts purifying. The start of purifying operation refers to the initial state of the space purification device 1.

[0032] At the start of the purification operation, the lid 14 is positioned in the z-axis direction above (on the positive side of the z-axis) the position of the liquid level S1 of the first aqueous solution L1 in the z-axis direction, and is fixed at this fixed position. If the lid 14 is not provided, the air supplied from the air supply unit 12 flows through the chloride tank-side internal space 13, causing the air to flow over the liquid level S1 of the first aqueous solution L1 and causing the first aqueous solution L1 to evaporate, but the provision of the lid 14 makes it possible to suppress excessive evaporation of the first aqueous solution L1.

[0033] Since the lid portion 14 is fixed at the fixed position, which is the above-mentioned predetermined position, the opening 15 allows the first aqueous solution L1 to flow out onto the upper surface side of the lid portion 14 (the xy plane on the positive side of the z-axis) when the liquid level S1 of the first aqueous solution L1 rises due to the purification operation of the space purification device 1.

[0034] The state in which the liquid level S1 of the first aqueous solution L1 exceeds the lid part 14 refers to a state in which the amount of the first aqueous solution L1 has unintentionally increased in the space purification device 1, resulting in an excessive amount of the first aqueous solution L1. Here, air supplied from the air supply part 12 flows over the liquid level S1 of the first aqueous solution L1 that has flowed out to the upper surface of the lid part 14, thereby promoting evaporation of the first aqueous solution L1. In this way, the lid part 14 having the opening 15 can suppress excessive evaporation of the first aqueous solution L1, while promoting evaporation of the excess first aqueous solution L1 that has flowed out to the upper surface of the lid part 14 when the amount of the first aqueous solution L1 becomes excessive.

[0035] The extension direction of lid portion 14 does not have to be along the xy plane, and lid portion 14 may be disposed at a predetermined inclination angle, which may be an angle between −45 degrees and +45 degrees in a front view, with the end of lid portion 14 on the negative side of the x axis as the origin.

[0036] The chloride tank 10 and the chlorine tank 20 are connected via a first connecting part 41. The first connecting part 41 is a member for supplying air A1 from the external space R into the second aqueous solution L2 in the chlorine tank 20 via the air supply part 12 and the chloride tank-side internal space 13. The first connecting part 41 is a tubular member that connects the chloride tank 10 and the chlorine tank 20. More specifically, one end (negative side of the x-axis) of the first connecting part 41 is connected to the chloride tank-side internal space 13 of the chloride tank 10, and the other end (positive side of the x-axis) is connected to the chlorine tank 20 at a position below (negative side of the z-axis) the liquid level S2 of the second aqueous solution L2 stored in the chlorine tank 20.

[0037] 1, the first connecting part 41 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 41 may be any tubular member that connects the chloride tank 10 and the chlorine tank 20 so that air A1 can flow between them.

[0038] As shown in FIG. 1, air A1 introduced from the external space R into the chloride tank-side internal space 13 via the air supply unit 12 is released as bubbles B1 into the second aqueous solution L2 stored in the chlorine tank 20 via the first connecting unit 41. In other words, bubbles B1 are generated by bubbling the second aqueous solution L2 with the air A1 introduced from the external space R. In FIG. 1, bubbles B1 are indicated by circles with diagonal hatching. The bubbles B1, i.e., mixed air A2 containing volatilized chlorine mixed with air A1, are supplied to the hypochlorous acid tank 30 via the second connecting unit 42 described below. The end of the first connecting unit 41 on the chlorine tank 20 side may be connected to the chlorine tank-side internal space 22. That is, instead of air A1 introduced from the external space R into the chloride tank 10 being supplied to the chlorine tank 20 as bubbles B1, air A1 introduced from the external space R into the chloride tank 10 may be supplied to the chlorine tank side internal space 22 as air A1.

[0039] By generating bubbles B1 in the second aqueous solution L2 by bubbling, chlorine can be captured in the bubbles B1 as they rise to the liquid surface S2 due to buoyancy. In other words, compared to gas-liquid contact between air taken in from the outside and the liquid surface S2 of the second aqueous solution L2, gas-liquid contact in which bubbles B1 are generated in the second aqueous solution L2 by bubbling captures more chlorine in the bubbles B1, and the chlorine-containing mixed air A2 can be supplied to the hypochlorous acid tank 30.

[0040] The chlorine tank 20 is a tank that stores a second aqueous solution L2 containing chloride ions and generates chlorine by subjecting the second aqueous solution L2 to first diaphragm electrolysis and second diaphragm electrolysis.

[0041] FIG. 1 shows a state in which the second aqueous solution L2 is stored in the chlorine tank 20. The second aqueous solution L2 is an aqueous solution containing chloride ions, and chlorine is generated by performing first diaphragm electrolysis and second diaphragm electrolysis, which will be described later, and the chlorine is supplied to the third aqueous solution L3, which will be described later. More specifically, the second aqueous solution L2 is an aqueous chloride solution containing a lithium chloride solution and a sodium chloride solution. When a lithium chloride solution is used as the second aqueous solution L2, the mass percent concentration of the lithium chloride solution is, for example, 12% to 39%. When a sodium chloride solution is used as the second aqueous solution L2, the mass percent concentration of the sodium chloride solution is, for example, 5% to 36%.

[0042] Here, when the concentration of the lithium chloride aqueous solution is 12%, the water level of the second aqueous solution L2 can be maintained without a significant decrease or increase when the relative humidity of the external space R is 85%. Also, when the concentration of the lithium chloride aqueous solution is 39%, the water level of the second aqueous solution L2 can be maintained without a significant decrease or increase when the relative humidity of the external space R is 20%.

[0043] Furthermore, when the concentration of the sodium chloride aqueous solution is 5%, the water level of the second aqueous solution L2 can be maintained without a significant decrease or increase when the relative humidity of the external space R is a predetermined humidity between 95% and 100%. Furthermore, when the concentration of the sodium chloride aqueous solution is 36%, the water level of the second aqueous solution L2 can be maintained without a significant decrease or increase when the relative humidity of the external space R is 76%.

[0044] Furthermore, for example, if a water tank capable of supplying water is provided in the chloride tank 10 and bubbles B1 are generated in the second aqueous solution L2 by bubbling, the space purification device 1 can be used while maintaining the water level of the second aqueous solution L2, even if a low-concentration chloride aqueous solution close to the lower limit value of the above-mentioned chloride aqueous solution is used.

[0045] The initial pH of the second aqueous solution L2 at the start of the initial operation of the space purification device 1 is, for example, pH 7. The pH of the second aqueous solution L2 gradually decreases as the purification operation continues, and after a predetermined operation time has elapsed, the pH drops to about pH 2 to 6. As the pH of the second aqueous solution L2 decreases, chlorine generation is promoted. .

[0046] The chlorine tank 20 includes a chlorine tank-side anode 21 and a chlorine tank-side internal space 22 .

[0047] The chlorine tank-side anode 21 is used in both the first membrane-with-diaphragm electrolysis and the second membrane-with-diaphragm electrolysis. The chlorine tank-side anode 21 is paired with the chloride tank-side cathode 11 via a first anion-exchange membrane 43 and is used in the first membrane-with-diaphragm electrolysis of the first aqueous solution L1 and the first membrane-with-diaphragm electrolysis of the second aqueous solution L2. The chlorine tank-side anode 21 is paired with the hypochlorous acid tank-side cathode 31 (described later) via a second anion-exchange membrane 44 and is used in the second membrane-with-diaphragm electrolysis.

[0048] Chlorine is generated by first diaphragm electrolysis and second diaphragm electrolysis in the chlorine tank-side anode 21. The generated chlorine volatilizes into the chlorine tank-side internal space 22 described below and is supplied to the hypochlorous acid tank 30 via the second connecting part 42. In FIG. 1, the mixed air A2 containing chlorine is indicated by an arrow hatched with thin diagonal lines going up to the right.

[0049] The chlorine tank anode 21 is inserted from the outside to the inside of the chlorine tank 20. The chlorine tank anode 21 has a plate-like shape. The plate-like shape includes a rectangular shape and a rectangular shape. An insoluble electrode may be used as the chlorine tank anode 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.

[0050] The chlorine tank-side internal space 22 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 chlorine 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 chlorine tank 20, and the chlorine tank-side internal space 22 is present. Mixed air A2 containing chlorine generated in the chlorine tank-side anode 21 volatilizes into the chlorine tank-side internal space 22. The mixed air A2 containing chlorine volatilized into the chlorine tank-side internal space 22 is supplied to the hypochlorous acid tank 30 via a second connection part 42, which will be described later.

[0051] The hypochlorous acid tank 30 stores a third aqueous solution L3 containing chloride ions, and the chlorine supplied from the chlorine tank 20 via the second connecting part 42 reacts with the water contained in the third aqueous solution L3 to produce hypochlorous acid, and the chloride ions contained in the third aqueous solution L3 are passed through the second anion exchange membrane 44 by second diaphragm electrolysis and supplied to the second aqueous solution L2.

[0052] FIG. 1 shows a state in which the third aqueous solution L3 is stored in the hypochlorous acid tank 30. The third aqueous solution L3 is an aqueous solution containing chloride ions. More specifically, the third aqueous solution L3 is an alkalized aqueous solution of a chloride solution having a mass percent concentration equivalent to that of the second aqueous solution L2. For example, the third aqueous solution L3 is a solution obtained by adding a sodium hydroxide aqueous solution to a chloride aqueous solution such as a lithium chloride aqueous solution or a sodium chloride aqueous solution. By making the third aqueous solution L3 a chloride aqueous solution having a mass percent concentration equivalent to that of the second aqueous solution L2, unintended water movement due to osmotic pressure that may occur between the chlorine tank 20 and the hypochlorous acid tank 30 can be suppressed, and the water levels of the second aqueous solution L2 and the third aqueous solution L3 can be maintained at approximately the same level.

[0053] When a lithium chloride aqueous solution is used as the third aqueous solution L3, the mass percentage concentration of the lithium chloride aqueous solution is, for example, 12% to 39%. When a sodium chloride aqueous solution is used as the third aqueous solution L3, the mass percentage concentration of the sodium chloride aqueous solution is, for example, 5% to 36%. When a sodium hydroxide aqueous solution is added to the lithium chloride aqueous solution or the sodium chloride aqueous solution, the third aqueous solution L3 is alkalized by adding a sodium hydroxide aqueous solution with a concentration of about 0.4% (0.1 mol / L). The initial pH of the alkalized third aqueous solution L3 at the start of initial operation of the space purification device 1 is, for example, pH 13. At the start of initial operation By alkalizing the third aqueous solution L3 in this step, the third aqueous solution L3 is more likely to absorb the chlorine generated in the second aqueous solution L2. Since the hypochlorous acid produced in the hypochlorous acid tank 30 is produced by a reaction between the chlorine generated in the second aqueous solution L2 and the water of the third aqueous solution L3, the promotion of absorption of chlorine in the third aqueous solution L3 promotes the generation of hypochlorous acid.

[0054] Here, when the concentration of the lithium chloride aqueous solution is 12%, the water level of the second aqueous solution L2 can be maintained without a significant decrease or increase when the relative humidity of the external space R is 85%. Also, when the concentration of the lithium chloride aqueous solution is 39%, the water level of the second aqueous solution L2 can be maintained without a significant decrease or increase when the relative humidity of the external space R is 20%.

[0055] The hypochlorous acid tank 30 includes a hypochlorous acid tank-side cathode 31, a hypochlorous acid tank-side internal space 32, a water collection unit 33, and a discharge port 34. The hypochlorous acid tank 30 may further include a water level detection unit 35.

[0056] The hypochlorous acid tank-side cathode 31 is used in the second membrane electrolysis. The hypochlorous acid tank-side cathode 31 is paired with the chlorine tank-side anode 21 via a second anion exchange membrane and used in the second membrane electrolysis. Chloride ions are supplied from the third aqueous solution L3 to the second aqueous solution L2 by the second membrane electrolysis of the third aqueous solution L3 performed using the pair of the hypochlorous acid tank-side cathode 31 and the chlorine tank-side anode 21.

[0057] The hypochlorous acid tank-side cathode 31 is inserted from the outside to the inside of the hypochlorous acid tank 30. The hypochlorous acid tank-side cathode 31 has a plate-like shape. Plate-like shapes include rectangular and oblong shapes. An insoluble electrode may be used as the hypochlorous acid tank-side cathode 31. 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.

[0058] The second anion exchange membrane 44 is a membranous member that connects the chlorine tank 20 and the hypochlorous acid tank 30 in a manner that allows anions to pass therethrough, based on a voltage applied between the chlorine tank 20 and the hypochlorous acid tank 30. More specifically, when a voltage is applied between the chlorine tank-side anode 21 and the hypochlorous acid tank-side cathode 31, second membrane-type electrolysis is carried out via the second anion exchange membrane 44. By the second membrane-type electrolysis using the chlorine tank-side anode 21 and the hypochlorous acid tank-side cathode 31, chloride ions contained in the third aqueous solution L3 permeate the second anion exchange membrane 44 and are supplied to the second aqueous solution L2 (indicated by a thick black arrow in the negative direction of the x-axis).

[0059] The second anion exchange membrane 44 in this embodiment is similar to the first anion exchange membrane 43. That is, the second anion exchange membrane 44 is not a type of anion exchange membrane through which anions permeate due to osmotic pressure without using electricity. The second anion exchange membrane 44 is, for example, a hydrocarbon-based anion exchange membrane, and includes membranes that have the properties of monovalent anion selective permeability, alkali resistance, and high temperature resistance.

[0060] The plane of the chlorine tank-side anode 21 on the second anion exchange membrane 44 side (the yz plane on the positive side of the x-axis) and the plane of the hypochlorous acid tank-side cathode 31 on the second anion exchange membrane 44 side (the yz plane on the negative side of the x-axis) are arranged opposite each other. This arrangement allows a uniform electric field to be generated between the chlorine tank-side anode 21 and the hypochlorous acid tank-side cathode 31. Because electrolysis is generated uniformly, the current between the two electrodes is also distributed uniformly. Therefore, deterioration of the catalytic layer on the surface of each electrode occurs uniformly, and therefore, even when electrolysis is performed repeatedly, uneven deterioration of the catalytic layer on the surface of each electrode due to an uneven electric field can be suppressed. Therefore, a decrease in electrolysis efficiency can be suppressed.

[0061] The chlorine tank anode 21 and the hypochlorous acid tank cathode 31 are disposed adjacent to the second anion exchange membrane 44. In this specification, the term "adjacent" refers to the distance between the chlorine tank anode 21 and the hypochlorous acid tank cathode 31. This refers to a state in which the chloric acid tank side cathode 31 is close to the second anion exchange membrane 44 with a predetermined gap therebetween.

[0062] The hypochlorous acid tank-side internal space 32 is an upper space (space on the positive z-axis side) formed above the liquid level S3 of the third aqueous solution L3 when the third aqueous solution L3 is stored in the hypochlorous acid tank 30. In other words, the third aqueous solution L3 is not stored up to the internal upper surface (xy plane on the positive z-axis side) of the hypochlorous acid tank 30, and the hypochlorous acid tank-side internal space 32 is present.

[0063] The chlorine tank 20 and the hypochlorous acid tank 30 are connected via a second connecting part 42. The second connecting part 42 is a member for supplying mixed air A2 containing chlorine generated in the chlorine tank 20 and volatilized in the chlorine tank-side internal space 22 into the third aqueous solution L3 stored in the hypochlorous acid tank 30. The second connecting part 42 is a tubular member that connects the chlorine tank 20 with the hypochlorous acid tank 30 described below. More specifically, one end (negative side of the x-axis) of the second connecting part 42 is connected to the chlorine tank-side internal space 22 of the chlorine tank 20, and the other end (positive side of the x-axis) is connected to the hypochlorous acid tank 30 at a position below (negative side of the z-axis) the liquid level S3 of the third aqueous solution L3 stored in the hypochlorous acid tank 30.

[0064] 1, the second connecting part 42 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 thereto. The second connecting part 42 may be a tubular member that connects the chlorine tank 20 and the hypochlorous acid tank 30 so that the chlorine-containing mixed air A2 can flow between them, and may be disposed so that the position in the z-axis direction of the end connected to the chlorine tank-side internal space 22 (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 hypochlorous acid tank 30 (the end on the positive side of the x-axis).

[0065] The chlorine-containing mixed air A2 generated in the chlorine tank 20 is mixed with bubbles B1 (air A1), volatilizes in the chlorine tank-side internal space 22, and is supplied to the hypochlorous acid tank 30 via the second connecting part 42. More specifically, the chlorine-containing mixed air A2 is released as bubbles B2 into the third aqueous solution L3 stored in the hypochlorous acid tank 30 via the second connecting part 42. In other words, bubbles B2 are generated by bubbling the third aqueous solution L3 with the chlorine-containing mixed air A2. In FIG. 1, bubbles B2 are indicated by circles with diagonal lines slanting downward to the right. The bubbles B2, i.e., the hypochlorous acid-containing mixed air A3 generated by the reaction of the chlorine-containing mixed air A2 with the water contained in the third aqueous solution L3, are released into the external space R. In FIG. 1, the hypochlorous acid-containing mixed air A3 is indicated by an arrow with thin diagonal lines slanting downward to the right.

[0066] By generating bubbles B2 in the third aqueous solution L3 by bubbling, chlorine dissolves in the third aqueous solution L3, and hypochlorous acid can be captured in the bubbles B2 as the bubbles B2 rise to the liquid surface S3 due to buoyancy. In other words, compared to gas-liquid contact between air taken in from the outside and the liquid surface S3 of the third aqueous solution L3, gas-liquid contact in which bubbles B2 are generated in the third aqueous solution L3 by bubbling allows more hypochlorous acid to be captured in the bubbles B2 and released into the external space R as mixed air A3 containing hypochlorous acid.

[0067] The water recovery unit 33 is a component that circulates inside the space purification device 1 and recovers, as liquid, moisture contained in the mixed air A3 containing hypochlorous acid, which is released from the hypochlorous acid tank 30 into the external space R, into the hypochlorous acid tank 30. The water recovery unit 33 is, for example, a Peltier element that can cool the moisture contained in the air, condense it, and turn it into water droplets. The water recovery unit 33 may be disposed at the outlet 34 through which the air circulating inside the space purification device 1 passes before being released into the external space R, in order to recover the moisture contained in the air circulating inside the space purification device 1. When the water recovery unit 33 is disposed at the outlet 34, the moisture contained in the air that has circulated inside the space purification device 1 can be efficiently recovered. The water recovery unit 33 may also be disposed in a part of the internal space 32 on the hypochlorous acid tank side.

[0068] The outlet 34 is for discharging the mixed air A3 containing hypochlorous acid into the external space R of the housing C. 1, the release port 34 is provided on the upper surface (xy plane on the positive side of the z-axis) of the hypochlorous acid tank 30 as an example, but it may be located above the liquid level S3 of the third aqueous solution L3. The shape of the release port 34 is tubular, and includes, for example, a cylindrical or rectangular tubular shape. When the upper surface (the surface on the positive side of the z-axis) of the hypochlorous acid tank 30 is close to the ceiling surface of the housing C, the release port 34 may be a hole-like opening provided in a part of the upper surface of the hypochlorous acid tank 30. Furthermore, the release port 34 and the upper surface (the surface on the positive side of the z-axis) of the housing C may be formed integrally.

[0069] The outlet 34 may be provided with an openable or detachable lid (not shown). The lid may be configured to be closed when the space purification device 1 is transported, moved, or installed, and to be openable or detachable when the space purification device 1 is in use.

[0070] The mixed air A3 containing hypochlorous acid is released from the outlet 34 into the external space R of the space purification device 1 to purify the external space R. That is, the mixed air A3 containing hypochlorous acid removes bacteria, fungi, viruses, odors, and the like contained in the air in the external space R of the housing C.

[0071] The water level detector 35 detects the position of the liquid level S3 of the third aqueous solution L3. The water level detector 35 is, for example, a water level sensor. The water level detector 35 is disposed at least above (on the positive z-axis side) the upper end (on the positive z-axis side) of the hypochlorous acid tank-side cathode 31.

[0072] When the space purification device 1 includes the water level detection unit 35, a water supply unit may be separately provided that supplies water to the hypochlorous acid tank 30 based on the position of the liquid level S1 detected by the water level detection unit 35. More specifically, the water supply unit supplies water to the hypochlorous acid tank 30 so that the water level does not fall below the upper end (the part on the positive side of the z-axis) of the hypochlorous acid tank-side cathode 31. Furthermore, one end (the end on the positive side of the x-axis) of a second connection unit 42 described below is connected to the hypochlorous acid tank 30 at a position below the liquid level S3 of the third aqueous solution L3 stored in the hypochlorous acid tank 30. The water supply unit supplies water to the hypochlorous acid tank 30 so that the water level does not fall below the upper end (the part on the positive side of the z-axis) of the second connection unit 42.

[0073] When the space purification device 1 includes the water level detector 35 and the water supplier, the hypochlorous acid tank-side cathode 31 can be kept immersed in the third aqueous solution L3. This prevents the hypochlorous acid tank-side cathode 31 from being exposed to air due to a decrease in the third aqueous solution L3, and maintains the electrolysis efficiency of the second diaphragm-equipped electrolysis.

[0074] The current control unit 50 controls the current used in the first diaphragm electrolysis and the second diaphragm electrolysis. The current control unit 50 is equipped with wiring 51, 52, and 53. The wiring 51, 52, and 53 are lines through which current flows. The chloride tank side cathode 11 is electrically connected to the current control unit 50 via wiring 51. The chlorine tank side anode 21 is electrically connected to the current control unit 50 via wiring 52. The hypochlorous acid tank side cathode 31 is electrically connected to the current control unit 50 via wiring 53. A portion of each electrode may protrude outside the respective tank and be connected to each wiring.

[0075] Next, the first diaphragm electrolysis unit E1 and the second diaphragm electrolysis unit E2 included in the space purification device 1 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a partial cross-sectional plan view taken along line II-II in Fig. 1. In Fig. 2, the first diaphragm electrolysis unit E1 is indicated by the area enclosed in a dashed-dotted line rectangle, and the second diaphragm electrolysis unit E2 is indicated by the area enclosed in a dashed-dotted line rectangle.

[0076] The first diaphragm electrolysis unit E1 is provided across the chloride tank 10 and the chlorine tank 20. The first diaphragm electrolysis unit E1 includes a chloride tank-side cathode 11, a chlorine tank-side anode 21, and a first anion exchange membrane 43. The first diaphragm electrolysis unit E1 generates anion exchange membrane 43 through the first anion exchange membrane 43 by passing a first current between the pair of the chloride tank-side cathode 11 and the chlorine tank-side anode 21. Perform disassembly.

[0077] The second membrane-equipped electrolysis unit E2 is provided across the chlorine tank 20 and the hypochlorous acid tank 30. The second membrane-equipped electrolysis unit E2 includes a chlorine tank-side anode 21, a hypochlorous acid tank-side cathode 31, and a second anion exchange membrane 44. The second membrane-equipped electrolysis unit E2 performs second membrane-equipped electrolysis via the second anion exchange membrane 44 by passing a second current between the pair of the chlorine tank-side anode 21 and the hypochlorous acid tank-side cathode 31.

[0078] The current control unit 50 controls the first current flowing through the first diaphragm electrolysis unit E1 and the second current flowing through the second diaphragm electrolysis unit E2, thereby controlling the chemical reactions occurring in the first diaphragm electrolysis unit E1 and the second diaphragm electrolysis unit E2.

[0079] Below, the chemical reaction occurring in the first diaphragm electrolysis unit E1 will be described in detail using Fig. 3, and the chemical reaction occurring in the second diaphragm electrolysis unit E2 will be described in detail using Fig. 4. The following describes a case where the first aqueous solution L1 is a magnesium chloride aqueous solution, the second aqueous solution L2 is a lithium chloride aqueous solution, and the third aqueous solution L3 is a mixed solution of a lithium chloride aqueous solution and a sodium hydroxide aqueous solution.

[0080] [First diaphragm electrolytic section E1] In the first membrane-type electrolysis unit E1, by passing a first current, a reaction occurs in both the chloride tank-side cathode 11 and the chlorine tank-side anode 21 via the first anion exchange membrane 43. That is, in the first membrane-type electrolysis unit E1, a reaction occurs in both the first aqueous solution L1 stored in the chloride tank 10 and the second aqueous solution L2 stored in the chlorine tank 20.

[0081] Fig. 3 is a list of chemical reaction formulas occurring in the first diaphragm electrolysis unit E1. More specifically, Fig. 3 is a list of chemical reactions occurring in the first aqueous solution L1 stored in the chloride tank 10 of the first diaphragm electrolysis unit E1 and chemical reactions occurring in the second aqueous solution L2 stored in the chlorine tank 20.

[0082] When a predetermined voltage is applied to the first membrane electrolysis unit E1, a first current flows, electrons move, and the chemical reaction shown in Fig. 3 occurs. Note that with respect to the chemical reactions occurring in the second aqueous solution L2 stored in the chlorine tank 20, as shown in reaction formulas (d) to (g) of Fig. 3, the following similar chemical reactions also occur in the second membrane electrolysis unit E2.

[0083] First, the reactions occurring in the first aqueous solution L1 stored in the chloride tank 10 will be described with reference to reaction formulas (a) to (c) in FIG.

[0084] <Chloride tank 10 (first aqueous solution L1)> (a) of FIG. 3: First anion exchange membrane 43 When a voltage is applied to the first diaphragm electrolysis unit E1 and a first current flows, chloride ions (Cl ) contained in the first aqueous solution L1 stored in the chloride tank 10 are dissolved in the first aqueous solution L1. - ) permeates the first anion exchange membrane 43 and is supplied to the second aqueous solution L2 stored in the chlorine tank 20. The chloride ions (Cl - ) is used in reaction formula (e) in FIG. 3, which will be described later. In addition, when a first current flows between the chloride tank cathode 11 and the chlorine tank anode 21, water (HO) in the first aqueous solution L1 is converted into electrons (e -In other words, in the first aqueous solution L1, the chloride ions (Cl - ) after the first current flows (after the change), electrons (e - ) The water (H2O) in the first aqueous solution L1 has electrons (e - The reaction that occurs when the cation is added is shown in reaction equation (b) in Figure 3 below.

[0085] Reaction formula (b) in Figure 3: Chloride tank side cathode 11 (hydrogen generation reaction) At the chloride tank side cathode 11, water (H2O) in the first aqueous solution L1 converts electrons (e - ) and hydrogen (H2) and hydroxide ions (OH - ) is generated. Hydrogen is supplied as a gas to the chlorine tank 20 via the first connection part 41, but does not contribute to the reaction. Hydroxide ions are used in the following reaction formula (c) in FIG. 3.

[0086] Reaction formula (c) in Figure 3: In the first aqueous solution L1 (magnesium hydroxide precipitation reaction) The magnesium ions (Mg 2+ ) and hydroxide ions (OH - ) reacts with magnesium hydroxide (Mg(OH)2) to form a metal hydroxide precipitate.

[0087] Here, the solubility product of magnesium hydroxide (Mg(OH)2) is Ksp = 1.2 × 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 first aqueous solution L1 of the chloride tank 10, hydroxide ions (OH - ) is used to generate magnesium hydroxide precipitates, and hydroxide ions (OH - ) and the increase in pH of the first aqueous solution L1 can be suppressed.

[0088] Furthermore, when a magnesium chloride aqueous solution is used as the first aqueous solution L1, the pH of the magnesium hydroxide saturated aqueous solution produced after the first membrane electrolysis, in which magnesium hydroxide is saturated, is 10.36 as determined from the solubility product. Therefore, even after the first membrane electrolysis is performed for a long period of time, the pH of the first aqueous solution L1 can be maintained in a weakly alkaline state of 10.36 or less.

[0089] Next, the reactions occurring in the second aqueous solution L2 stored in the chlorine tank 20 will be described with reference to reaction formulas (d) to (g) in FIG.

[0090] <Chlorine tank 20 (second aqueous solution L2)> (d) of FIG. 3: First anion exchange membrane 43 When a voltage is applied to the first diaphragm electrolysis unit E1 and a first current flows, the first current flows between the chloride tank side cathode 11 and the chlorine tank side anode 21, and electrons (e - ) contained in the first aqueous solution L1 stored in the chloride tank 10 moves. - ) permeates the first anion exchange membrane 43 and is supplied to the second aqueous solution L2 stored in the chlorine tank 20. The chloride ions (Cl - ) is used in the following reaction formula (e) in FIG. 3. In other words, in the second aqueous solution L2, the electrons (e - ) is converted into chloride ions (Cl - ) can be said to be

[0091] Subsequently, as shown in reaction formula (e) and reaction formula (f) in FIG. 3, two types of reactions occur at the chlorine tank side anode 21: generation of chlorine and generation of oxygen. Reaction formula (e) in Figure 3: Chlorine tank side anode 21 (chlorine generation reaction) The lithium chloride (LiCl) contained in the lithium chloride aqueous solution, which is the third aqueous solution L3, converts into lithium ions (Li + ) and chloride ions (Cl- ) into chloride ions (Cl ). As described above in reaction formula (a) of FIG. 3, chloride ions (Cl ) are released from the first aqueous solution L1 into the third aqueous solution L3 through the first anion exchange membrane 43. - ) is supplied to the chlorine tank side anode 21. The chloride ions (Cl - ) and chloride ions (Cl ) supplied from the third aqueous solution L3 - ) is an electron (e - ) and chlorine (Cl2 (liquid, aq.)) is produced.

[0092] Reaction formula (f) in Figure 3: Chlorine tank side anode 21 (oxygen generation reaction) At the chlorine tank side anode 21, electrons (e - ) is taken away, and oxygen (O2) and hydrogen ions (H + ) occurs.

[0093] Reaction equation (g) in Figure 3: Equilibrium reaction equation The equilibrium reaction between chlorine and hypochlorous acid is shown in Figure 3. + The generation of chlorine (liquid) causes the pH of the second aqueous solution L2 to decrease, shifting the equilibrium reaction equation to the left and promoting the generation of chlorine (liquid). The promotion of the generation of chlorine (liquid) increases the amount of chlorine gas that evaporates.

[0094] Reaction equation (h) in Figure 3: Equilibrium reaction equation The equilibrium reaction formula of hypochlorite ions, hypochlorous acid, and chlorine is shown below. When the pH of the second aqueous solution L2 stored in the chlorine tank 20 is equal to or lower than a predetermined pH, for example, 7.5 or lower, the hypochlorite ions (ClO - ) in the second aqueous solution is converted to hydrogen ions (H + ) to generate hypochlorous acid (liquid). Furthermore, when the pH of the second aqueous solution L2 stored in the chlorine tank 20 is equal to or lower than a predetermined pH, for example, pH 6 or lower, the hydrogen ions (H + ), chloride ions (Cl -) and hypochlorous acid (liquid) generate chlorine. The generation of hypochlorous acid ions will be described later using reaction formula (f) in Figure 4. The chlorine is supplied to the hypochlorous acid tank 30 via the second connecting part 42 as mixed air A2 containing chlorine.

[0095] [Second diaphragm electrolytic section E2] In the second membrane-type electrolysis unit E2, a second current is passed, causing a reaction to occur in both the chlorine tank-side anode 21 and the hypochlorous acid tank-side cathode 31 via the second anion exchange membrane 44. That is, in the second membrane-type electrolysis unit E2, a reaction occurs in both the second aqueous solution L2 stored in the chlorine tank 20 and the third aqueous solution L3 stored in the hypochlorous acid tank 30. When a predetermined voltage is applied to the second membrane-type electrolysis unit E2, the second current flows, electrons are transferred, and the chemical reaction shown in FIG. 4 occurs.

[0096] FIG. 4 is a list of chemical reaction formulae occurring in the second diaphragm electrolysis unit. More specifically, FIG. 4 is a list of chemical reactions occurring in the third aqueous solution L3 stored in the hypochlorous acid tank 30 of the second diaphragm electrolysis unit E2. The list of chemical reactions occurring in the second aqueous solution L2 stored in the chlorine tank 20 in the second diaphragm electrolysis unit E2 has been explained using reaction formulae (d) to (g) in FIG. 3, and therefore will not be explained further below. However, with regard to (d) in FIG. 3, as follows, after the first current flows (after change), chloride ions and hypochlorous acid ions (ClO - ) is different from that in (d) of FIG. 3: When a voltage is applied to the first diaphragm electrolysis unit E1 and a first current flows, the first current flows between the chloride tank side cathode 11 and the chlorine tank side anode 21, and electrons (e - ) contained in the first aqueous solution L1 stored in the chloride tank 10 moves. - ) and hypochlorite ion (ClO - ) permeates the first anion exchange membrane 43 and is supplied to the second aqueous solution L2 stored in the chlorine tank 20. In other words, in the second aqueous solution L2, the electrons (e -) is converted into chloride ions (Cl - ) and hypochlorite ion (ClO - ) can be said to be

[0097] <Hypochlorous acid tank 30 (third aqueous solution L3)>

[0098] Reaction formula (a) in Figure 4: In the third aqueous solution L3 (hypochlorous acid generation reaction) In the third aqueous solution L3 stored in the hypochlorous acid tank 30, the chlorine (Cl2) supplied from the chlorine tank 20 undergoes a hydrolysis reaction with the water (H2O) of the third aqueous solution L3 to produce hydrochloric acid (HCl) and Chlorous acid (HClO) is generated. Hydrochloric acid (HCl) ionizes in an aqueous solution, forming hydrogen ions (H + ) and chloride ions (Cl - ) exists.

[0099] Reaction formula (b) in Figure 4: Chloride ion transformation during electrolysis Reaction formula (b) in Figure 4 is a single formula that combines reaction formula (e) in Figure 3 (chlorine generation reaction) and reaction formula (a) in Figure 4. Chlorine (Cl2) generated in the chlorine tank 20 (reaction formula (e) in Figure 3) changes into hydrochloric acid (HCl) and hypochlorous acid (HClO) according to reaction formula (d) in Figure 4.

[0100] (c) of FIG. 4: Second anion exchange membrane 44 When a voltage is applied to the second diaphragm electrolysis unit E2 and a second current flows, chloride ions (Cl ) contained in the third aqueous solution L3 stored in the hypochlorous acid tank 30 are - ) and at least some hypochlorite ions (ClO - ) permeates the second anion exchange membrane 44 and is supplied to the second aqueous solution L2 stored in the chlorine tank 20. The chloride ions (Cl - ) is used in the reaction formula (e) in Figure 3 above, and the hypochlorite ions (ClO -) is used in the reaction formula (h) in Figure 3 above. In addition, when a second current flows between the chlorine tank side anode 21 and the hypochlorous acid tank side cathode 31, the water (HO) of the third aqueous solution L3 is converted into electrons (e - ) in the third aqueous solution L3 before the second current flows (before the change). - ) and hypochlorite ion (ClO - ) after the second current flows (after the change), electrons (e - ) In other words, the chloride ions (Cl - ) and hypochlorite ion (ClO - ) and the total number of electrons (e - ) is the same as the number of electrons (e - The reaction that occurs when the third aqueous solution L3 receives the chlorine atom is shown in reaction formula (d) in Figure 4 below. The hypochlorous acid generating reaction in the third aqueous solution L3 is shown in reaction formula (f) in Figure 4 below.

[0101] Reaction formula (d) in Figure 4: Hypochlorous acid tank side cathode 31 (hydrogen generation reaction) At the hypochlorous acid tank cathode 31, the water (H2O) of the third aqueous solution L3 is converted into electrons (e - ) and hydrogen (H2) and hydroxide ions (OH - ) is generated. The hydrogen is released as a gas from the outlet 34. When the pH of the third aqueous solution L3 is, for example, about pH 8 to 9, the concentration of hydroxide ions contained in the third aqueous solution L3 becomes extremely low, and therefore, the hydroxide ions hardly permeate the second anion exchange membrane 44 and are used in the following reaction formula (e) in FIG. 4.

[0102] Reaction (e) in Figure 4: Chloride ion generation reaction A portion of the hydrochloric acid (HCl) reacts with the hydroxide ions produced by reaction formula (d) in Fig. 4 to produce water and chloride ions. The chloride ions are supplied to the second aqueous solution L2 through the second anion exchange membrane 44.

[0103] Reaction formula (f) in Figure 4: Hypochlorite ion generation reaction The third aqueous solution L3 is alkalized, and the initial pH is about pH 13. According to the dissociation constant of hypochlorous acid, when the pH is higher than 7.5, the hypochlorous acid remaining in the third aqueous solution L3 without being released from the outlet 34 is converted into hypochlorous acid ions (ClO - At least a portion of the hypochlorite ions produced in the third aqueous solution L3 permeates through the second anion exchange membrane 44 by the second diaphragm electrolysis and is supplied to the second aqueous solution. When the pH of the second aqueous solution L2 becomes equal to or lower than a predetermined pH, the hypochlorite ions supplied to the second aqueous solution L2 react with chloride ions in the second aqueous solution to produce chlorine (see reaction formula (h) in FIG. 3).

[0104] The above is a detailed description of the chemical reaction occurring in the first diaphragm electrolysis unit E1 provided between the chloride tank 10 and the chlorine tank 20, and the chemical reaction occurring in the second diaphragm electrolysis unit E2 provided between the chlorine tank 20 and the hypochlorous acid tank 30.

[0105] The current control unit 50 controls the first diaphragm electrolysis and the second diaphragm electrolysis. The current control unit 50 applies the first current and the second current at a predetermined ratio so as to replenish chloride ions lost due to a chemical reaction in the second aqueous solution L2 and maintain the concentration of hypochlorous acid produced in the third aqueous solution L3 at a predetermined concentration.

[0106] Here, the ions supplied to the second aqueous solution L2 stored in the chlorine tank 20 from the first aqueous solution L1 stored in the chloride tank 10 are only chloride ions, while the ions supplied from the third aqueous solution L3 stored in the hypochlorous acid tank 30 are chloride ions and hypochlorous acid ions.

[0107] There are two types of consumption of chloride ions in the second aqueous solution L2 stored in the chlorine tank 20. The first is (1) consumption of chloride ions by the first diaphragm electrolysis and the second diaphragm electrolysis. The second is (2) consumption of chloride ions by being used in a reaction with hypochlorite ions supplied from the third aqueous solution L3 stored in the hypochlorous acid tank 30 to the second aqueous solution L2 stored in the chlorine tank 20.

[0108] In the above (1), when the first current of the first membrane electrolysis is "A", the second current of the second membrane electrolysis is "B", and the current ratio of the current used for producing chlorine at the chlorine tank side anode 21 is "α", the consumption of chloride ions by the first membrane electrolysis and the second membrane electrolysis can be expressed as "α(A+B)".

[0109] The above (2) is a consumption in the reaction shown in reaction formula (h) of FIG. 3. When the pH of the second aqueous solution L2 stored in the chlorine tank 20 becomes a predetermined pH or less, the hydrogen ions (H + ), chloride ions (Cl - ) and hypochlorous acid (liquid) generate chlorine, which is supplied to the third aqueous solution L3. The hypochlorite ions (ClO ) supplied from the third aqueous solution L3 to the second aqueous solution L2 through the second anion exchange membrane 44 by the second current of the second diaphragm electrolysis are - ) and chloride ions (Cl - ), chloride ions (Cl - ) is defined as "β". In the second aqueous solution L2, the ratio of the hypochlorite ions (ClO - ) and the same amount of chloride ions (Cl - ) is used in the reaction shown in reaction formula (h) of Figure 3, so the chloride ions (Cl - ) consumption is "(1-β)B".

[0110] Here, the chloride ions (Cl) from the first aqueous solution L1 and the third aqueous solution L3 to the second aqueous solution L2 are - When the chemical reaction occurring in the chlorine tank 20 and the chemical reaction occurring in the hypochlorous acid tank 30 reach a steady state, the amount of chloride ions (Cl - ) consumption = Chloride ions (Cl - ) supply, the following equation 1 holds: α(A+B)+(1-β)B=A+βB (Formula 1)

[0111] By rearranging the above formula 1, we can obtain the chloride ion (Cl- ) increase = chloride ions (Cl - ) supply amount" - "chloride ions (Cl - ) consumption, the following equation 2 holds true. Chloride ions (Cl - ) Increase = A(1 - α) - B(1 + α - 2β) (Equation 2)

[0112] When the current ratio "α" of the current used to generate chlorine in the chlorine tank-side anode 21, that is, the chlorine generation efficiency α, decreases, the increase in the amount of chloride ions contained in the second aqueous solution L2 increases.

[0113] When the chemical reaction occurring in the chlorine tank 20 and the chemical reaction occurring in the hypochlorous acid tank 30 reach a steady state, the current control unit 50 calculates the "chloride ion (Cl - The current ratio between the first current and the second current is changed so that the "increase amount" becomes zero.

[0114] An example of current control by the current control unit 50 is a control in which a first current is passed between the chloride tank side cathode 11 and the chlorine tank side anode 21 at a predetermined current amount, and the current amount of a second current is increased between the chlorine tank side anode 21 and the hypochlorous acid tank side cathode 31 according to a predetermined elapsed time.

[0115] When the chemical reactions occurring in the chlorine tank 20 and the hypochlorous acid tank 30 reach a steady state, the amount of chloride ions supplied from the first aqueous solution L1 stored in the chloride tank 10 to the second aqueous solution L2 stored in the chlorine tank 20 becomes equal to the amount of hypochlorous acid released from the hypochlorous acid tank 30. In order to stably release the desired amount of hypochlorous acid gas, when the chemical reactions occurring in the chlorine tank 20 and the hypochlorous acid tank 30 reach a steady state, the first current is supplied at a predetermined amount.

[0116] By supplying a predetermined amount of the first current and increasing the amount of the second current, the pH of the third aqueous solution L3 stored in the hypochlorous acid tank 30 can be maintained high, and the amount of hypochlorous acid generated increases. In this case, even if the amount of chloride ions contained in the second aqueous solution L2 stored in the chlorine tank 20 decreases, the efficiency of chlorine production decreases, so the amount of chloride ions contained in the second aqueous solution L2 increases again after a predetermined time has passed. On the other hand, if the amount of chloride ions contained in the second aqueous solution L2 stored in the chlorine tank 20 increases more than the desired amount, the efficiency of chlorine production increases, so the amount of chloride ions contained in the second aqueous solution L2 decreases to the desired amount after a predetermined time has passed.

[0117] Therefore, by flowing the first current and the second current at a predetermined ratio, the current control unit 50 supplies chloride ions from the first aqueous solution L1 and the third aqueous solution L3 to the second aqueous solution L2 so as to replenish the chloride ions in the second aqueous solution L2 consumed by the first diaphragm electrolysis and the second diaphragm electrolysis and the chloride ions in the second aqueous solution L2 consumed by reacting with hypochlorite ions.

[0118] As described above, the chloride ions consumed by the second aqueous solution L2 can be appropriately supplied from the first aqueous solution L1 and the third aqueous solution L3, 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.

[0119] It is also possible to provide a plurality of current control units 50 and control the first current and the second current separately.

[0120] In this embodiment, the purification operation in which air introduced from the external space R flows through the chloride tank 10, the chlorine tank 20, and the hypochlorous acid tank 30 and is released into the external space together with hypochlorous acid has been described, but is not limited to this. For example, instead of introducing air A1 from the external space R into the chloride tank 10, a purification operation may be performed in which air A1 is introduced directly from the external space R into the chlorine tank 20, flows through the chlorine tank 20 and the hypochlorous acid tank 30, and is released into the external space R together with hypochlorous acid.

[0121] As described above, the space purification device 1 according to the first embodiment can provide the following effects.

[0122] The space purification device 1 according to this embodiment includes a chloride tank 10 that stores a first aqueous solution L1 containing chloride ions and supplies the chloride ions contained in the first aqueous solution L1 to a second aqueous solution L2 by passing them through a first anion exchange membrane 43 through a first diaphragm electrolysis, a chlorine tank 20 that stores a second aqueous solution L2 containing chloride ions and generates chlorine by subjecting the second aqueous solution L2 to first and second diaphragm electrolysis, and a chlorine tank 21 that stores a third aqueous solution L3 containing chloride ions. and a hypochlorous acid tank 30 in which chlorine supplied from the chlorine tank 20 reacts with water contained in the third aqueous solution L3 to generate hypochlorous acid, and in which chloride ions contained in the third aqueous solution L3 are permeated through a second anion exchange membrane 44 by second diaphragm electrolysis to be supplied to the second aqueous solution L2. A purification operation is performed in which air introduced from the external space R flows through the chlorine tank 20 and the hypochlorous acid tank 30 and is released into the external space together with hypochlorous acid.

[0123] With the above configuration, chloride ions are supplied from the first aqueous solution L1 stored in the chloride tank 10 to the second aqueous solution L2 stored in the chlorine tank 20, and chlorine generated in the second aqueous solution L2 is supplied to the third aqueous solution L3 stored in the hypochlorous acid tank 30. Because chloride ions can be supplied from the chloride tank 10 to the chlorine tank 20, 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 outside.

[0124] Furthermore, in the spatial purification device 1 according to this embodiment, the chloride tank 10 includes a chloride tank-side cathode 11, the chlorine tank 20 includes a chlorine tank-side anode 21, and the hypochlorous acid tank 30 includes a hypochlorous acid tank-side cathode 31. The spatial purification device 1 is also provided with a first diaphragm electrolysis unit E1 that is provided across the chloride tank 10 and the chlorine tank 20 and performs first diaphragm electrolysis via a first anion exchange membrane 43 by passing a first current between the chloride tank-side cathode 11 and the chlorine tank-side anode 21, and a second diaphragm electrolysis unit E2 that is provided across the chlorine tank 20 and the hypochlorous acid tank 30 and performs second diaphragm electrolysis via a second anion exchange membrane 44 by passing a second current between the chlorine tank-side anode 21 and the hypochlorous acid tank-side cathode 31.

[0125] With the above configuration, by passing the first current, chloride ions are supplied from the first aqueous solution L1 stored in the chloride tank 10 to the second aqueous solution L2 stored in the chlorine tank 20 via the first anion exchange membrane 43. Since chloride ions can be supplied from the chloride tank 10 to the chlorine tank 20, 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 outside.

[0126] The space purification device 1 according to this embodiment also includes a current control unit 50 that controls the first diaphragm electrolysis and the second diaphragm electrolysis. The current control unit 50 applies the first current and the second current at a predetermined ratio so that the concentration of hypochlorous acid produced in the third aqueous solution L3 is maintained at a predetermined concentration.

[0127] With the above configuration, the concentration of hypochlorous acid produced in the third aqueous solution L3 stored in the hypochlorous acid tank 30 can be maintained at a predetermined concentration even if the amount of chloride ions consumed in the chlorine tank 20 increases or decreases. 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.

[0128] Furthermore, in the space purification device 1 according to this embodiment, at least a portion of the hypochlorite ions produced in the third aqueous solution L3 permeates through the second anion exchange membrane 44 by the second diaphragm electrolysis and is supplied to the second aqueous solution L2. When the pH of the second aqueous solution L2 stored in the chlorine tank 20 becomes equal to or lower than a predetermined pH, the hypochlorite ions supplied from the third aqueous solution L3 react with chloride ions in the second aqueous solution L2 to produce chlorine. The current control unit 50 supplies chloride ions from the first aqueous solution L1 and the third aqueous solution L3 to the second aqueous solution L2 by applying the first current and the second current at a predetermined ratio, so as to replenish the chloride ions in the second aqueous solution L2 consumed by the first diaphragm electrolysis and the second diaphragm electrolysis and the chloride ions in the second aqueous solution L2 consumed by reacting with the hypochlorite ions.

[0129] With the above configuration, chloride ions consumed by the second aqueous solution L2 can be appropriately supplied from the first aqueous solution L1 and the third aqueous solution L3, thereby providing the space purification device 1 that can stably generate a desired amount of hypochlorous acid gas. 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, such as one year, without supplying an aqueous solution containing chloride ions from the outside.

[0130] Furthermore, in the space purification device 1 according to this embodiment, the air A1 supplied to the chlorine tank 20 is released as bubbles B2 into the third aqueous solution L3 stored in the hypochlorous acid tank 30, the released bubbles B2 are mixed with hypochlorous acid, and the resulting mixed air A3 is released into the external space.

[0131] With the above configuration, bubbles B2 are generated in the third aqueous solution L3 by bubbling, and hypochlorous acid can be captured in the bubbles B2 as they rise to the liquid surface S3 due to buoyancy. In other words, compared to gas-liquid contact between air taken in from the outside and the liquid surface S3 of the third aqueous solution L3, gas-liquid contact in which bubbles B2 are generated in the third aqueous solution L3 by bubbling allows more hypochlorous acid to be captured in the bubbles B2 and released into the external space R as mixed air A3 containing hypochlorous acid.

[0132] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention.

[0133] An outline of one aspect of the present disclosure is as follows.

[0134] (Item 1) a chloride tank (10) for storing a first aqueous solution (L1) containing chloride ions and for supplying the chloride ions contained in the first aqueous solution (L1) to a second aqueous solution (L2) by passing the chloride ions through a first anion exchange membrane (43) by first membrane electrolysis; a chlorine tank (20) for storing the second aqueous solution (L2) containing chloride ions and for generating chlorine by subjecting the second aqueous solution (L2) to the first diaphragm electrolysis and the second diaphragm electrolysis; a hypochlorous acid tank (30) that stores a third aqueous solution (L3) containing chloride ions, in which the chlorine supplied from the chlorine tank (20) reacts with water contained in the third aqueous solution (L3) to generate hypochlorous acid, and in which the chloride ions contained in the third aqueous solution (L3) are permeated through a second anion exchange membrane (44) by the second diaphragm electrolysis and supplied to the second aqueous solution (L2); Equipped with A purification operation is performed in which air introduced from an external space flows through the chlorine tank (20) and the hypochlorous acid tank (30) and is released into the external space (R) together with the hypochlorous acid. Space Purification Device (1). (Item 2) The chloride tank (10) is provided with a chloride tank-side cathode (11), The chlorine tank (20) includes a chlorine tank-side anode (21), The hypochlorous acid tank (30) includes a hypochlorous acid tank-side cathode (31), a first membrane-type electrolysis section provided across the chloride tank (10) and the chlorine tank (20), which performs the first membrane-type electrolysis via the first anion-exchange membrane (43) by passing a first current between the chloride tank-side cathode (11) and the chlorine tank-side anode (21); a second membrane-type electrolysis section provided across the chlorine tank (20) and the hypochlorous acid tank (30), which performs the second membrane-type electrolysis via the second anion-exchange membrane (44) by passing a second current between the chlorine tank-side anode (21) and the hypochlorous acid tank-side cathode (31); Equipped with The space purification device (1) according to item 1. (Item 3) a current control unit (50) for controlling the first membrane electrolysis and the second membrane electrolysis, The current control unit (50) The first current and the second current are applied at a predetermined ratio so that the concentration of the hypochlorous acid generated in the third aqueous solution (L3) is maintained at a predetermined concentration. Item 2. The space purification device according to item 2. (Item 4) At least a portion of the hypochlorite ions produced in the third aqueous solution (L3) permeates through the second anion exchange membrane (44) by the second membrane electrolysis and is supplied to the second aqueous solution (L2), When the pH of the second aqueous solution (L2) stored in the chlorine tank (20) becomes equal to or lower than a predetermined pH, hypochlorite ions supplied from the third aqueous solution (L3) react with chloride ions in the second aqueous solution (L2) to generate chlorine, the current control unit (50) supplies chloride ions from the first aqueous solution (L1) and the third aqueous solution (L3) to the second aqueous solution (L2) so as to replenish chloride ions in the second aqueous solution (L2) consumed by the first diaphragm electrolysis and the second diaphragm electrolysis and chloride ions in the second aqueous solution (L2) consumed by reacting with the hypochlorite ions, by causing the first current and the second current to flow at the predetermined ratio; The space purification device (1) described in the item. (Item 5) The space purification device (1) according to any one of items 1 to 4, wherein the air (A1) supplied to the chlorine tank (20) is released as bubbles (B2) into the third aqueous solution (L3) stored in the hypochlorous acid tank (30), the released bubbles (B2) are mixed with the hypochlorous acid, and the resulting mixed air (A3) is released into the external space (R). [Explanation of symbols]

[0135] 1. Space Purification Device 10 Chloride bath 11 Chloride tank side cathode 12 Air supply section 13 Chloride tank side internal space 14 Lid 15 Opening 20 Chlorine tank 21 Chlorine tank side anode 22 Chlorine tank side internal space 30 Hypochlorous Acid Tank 31 Hypochlorous acid tank side cathode 32 Hypochlorous acid tank side internal space 33 Water recovery section 34 Outlet 35 Water level detection unit 41 1st connection part 42 2nd connection part 43 First anion exchange membrane 44 Second anion exchange membrane 50 Current control section 51 Wiring 52 Wiring 53 Wiring A1 Air A2 Chlorine-containing air mixture A3 Mixed air containing hypochlorous acid B1 Bubbles B2 Bubbles E1 1st diaphragm electrolytic section E2 Second diaphragm electrolytic section L1 1st aqueous solution L2 2nd aqueous solution L3 3rd aqueous solution R External space

Claims

1. a chloride tank for storing a first aqueous solution containing chloride ions and for supplying chloride ions contained in the first aqueous solution to a second aqueous solution by passing the chloride ions through a first anion exchange membrane through a first diaphragm electrolysis; a chlorine tank for storing the second aqueous solution containing chloride ions and generating chlorine by subjecting the second aqueous solution to the first diaphragm electrolysis and the second diaphragm electrolysis; a hypochlorous acid tank that stores a third aqueous solution containing chloride ions, in which the chlorine supplied from the chlorine tank reacts with water contained in the third aqueous solution to generate hypochlorous acid, and in which the chloride ions contained in the third aqueous solution are permeated through a second anion exchange membrane by the second diaphragm electrolysis and supplied to the second aqueous solution; Equipped with A purification operation is performed in which air introduced from the external space flows through the chlorine tank and the hypochlorous acid tank and is released into the external space together with the hypochlorous acid. Space purification device.

2. the chloride bath includes a chloride bath-side cathode; The chlorine tank includes a chlorine tank-side anode, The hypochlorous acid tank includes a hypochlorous acid tank-side cathode, a first membrane-with-diaphragm electrolysis unit provided across the chloride tank and the chlorine tank, which performs the first membrane-with-diaphragm electrolysis via the first anion exchange membrane by passing a first current between the chloride tank-side cathode and the chlorine tank-side anode; a second membrane-with-diaphragm electrolysis unit provided across the chlorine tank and the hypochlorous acid tank, which performs the second membrane-with-diaphragm electrolysis via the second anion exchange membrane by passing a second current between the chlorine tank-side anode and the hypochlorous acid tank-side cathode; Equipped with The space purification device according to claim 1 .

3. a current control unit for controlling the first membrane electrolysis and the second membrane electrolysis, The current control unit The first current and the second current are applied at a predetermined ratio so that the concentration of hypochlorous acid generated in the third aqueous solution is maintained at a predetermined concentration. The space purification device according to claim 2 .

4. At least a portion of the hypochlorite ions produced in the third aqueous solution are supplied to the second aqueous solution by permeating the second anion exchange membrane through the second diaphragm electrolysis, When the pH of the second aqueous solution stored in the chlorine tank becomes equal to or lower than a predetermined pH, hypochlorite ions supplied from the third aqueous solution react with chloride ions in the second aqueous solution to generate chlorine, the current control unit supplies chloride ions from the first aqueous solution and the third aqueous solution to the second aqueous solution so as to replenish chloride ions in the second aqueous solution consumed by the first diaphragm electrolysis and the second diaphragm electrolysis and chloride ions in the second aqueous solution consumed by reacting with the hypochlorite ions, by causing the first current and the second current to flow at the predetermined ratio. The space purification device according to claim 3 .

5. The air supplied to the chlorine tank is released as bubbles into the third aqueous solution stored in the hypochlorous acid tank, and the released bubbles are mixed with the hypochlorous acid. The space purification device according to any one of claims 1 to 4, wherein the mixed air is released into the external space.

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