Space purifier

Abstract

To provide a space purifier capable of stably generating a desired amount of hypochlorous acid gas without supplying an aqueous solution including a chloride ion from outside for a long period of time.SOLUTION: An space purifier 1 includes: an electrolytic tank 10 configured to store a first aqueous solution L1; a first supply tank 20a configured to store a second aqueous solution L2 and supply OH- to the first aqueous solution L1; a second supply tank 20b configured to store a third aqueous solution L3 and supply Cl- to the first aqueous solution L1; a first anionic exchange membrane 30a connecting the electrolytic tank 10 and the first supply tank 20a; a second anionic exchange membrane 30b connecting the electrolytic tank 10 and the second supply tank 20b in a manner allowing an anion to pass through on the basis of a voltage applied between an electrolytic bath-side anode 11 and a second supply tank-side cathode 21; and a current control part configured to control an electric current so as to supplement Cl- having been reduced when generating a hypochlorous acid through a diaphragm electrolysis to the first aqueous solution L1, let the Cl- included in the third aqueous solution L3 pass through the second anionic exchange membrane 30b, and supply to the first aqueous solution L1.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 purifier that removes bacteria, fungi, viruses, odors, and the like from the air using hypochlorous acid generated by electrolyzing an aqueous solution containing chloride ions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-174032 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a conventional space purification device is miniaturized, the tank for storing the aqueous solution used for electrolysis is also made smaller. When the tank is made smaller, the amount of aqueous solution that can be stored is reduced compared to conventional space purification devices. Therefore, when electrolysis is repeatedly performed in a miniaturized space purification device, the chloride ion concentration in the aqueous solution is likely to decrease, and there is a problem that the amount of hypochlorous acid generated is not stable.

[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 according to the present invention includes an electrolytic cell for storing a first aqueous solution containing chloride ions, a first supply cell for storing a second aqueous solution containing hydroxide ions and supplying hydroxide ions to the first aqueous solution, a second supply cell for storing a third aqueous solution containing a higher concentration of chloride ions than the first aqueous solution and supplying chloride ions to the first aqueous solution, an electrolytic cell-side anode provided in the electrolytic cell, a first supply cell-side cathode provided in the first supply cell, a second supply cell-side cathode provided in the second supply cell, a first anion exchange membrane connecting the electrolytic cell and the first supply cell to be permeable to anions based on a voltage applied between the electrolytic cell-side anode and the first supply cell-side cathode, and a second anion exchange membrane connecting the electrolytic cell and the second supply cell to be permeable to anions based on a voltage applied between the electrolytic cell-side anode and the second supply cell-side cathode. a first membrane-with-diaphragm electrolysis section provided between the electrolytic cell and the first supply cell, which performs first membrane-with-diaphragm electrolysis of the first aqueous solution and the second aqueous solution via the first anion exchange membrane by passing a first current between the electrolytic cell-side anode and the first supply cell-side cathode to produce hypochlorous acid in the electrolytic cell; a second membrane-with-diaphragm electrolysis section provided between the electrolytic cell and the second supply cell, which performs second membrane-with-diaphragm electrolysis via the second anion exchange membrane by passing a second current between the electrolytic cell-side anode and the second supply cell-side cathode; and a current control section which controls the second current so as to compensate for chloride ions contained in the first aqueous solution that have been reduced by the first membrane-with-diaphragm electrolysis, thereby causing chloride ions contained in the third aqueous solution to permeate through the second anion exchange membrane and supply them to the first aqueous solution. Effect of the Invention

[0007] According to the present invention, it is possible to provide 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 description of the drawings]

[0008] [Figure 1] FIG. 1 is a side cross-sectional view showing a spatial purification device according to the first embodiment. [Diagram 2] FIG. 2 is a top view showing the spatial purification device of FIG. [Diagram 3]FIG. 3 is a diagram showing the formulas of the chemical reactions that occur in the first membrane electrolysis unit and the second membrane electrolysis unit that are constituted by the respective tanks of the spatial purification device. [Figure 4] FIG. 4 is a diagram showing the formulas of the chemical reactions that occur in the first membrane electrolysis unit and the second membrane electrolysis unit that are constituted by the tanks of the spatial purification device. [Diagram 5] FIG. 5 is a block diagram showing a current control unit that constitutes the spatial purification device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

[0010] The right-handed xyz coordinate system shown in the drawings is for the convenience of explaining the positional relationship of the components. Unless otherwise specified, the positive direction of the z axis is the vertical upward direction. In addition, the xy plane is a horizontal plane, and is common to all drawings. <Embodiment 1> A spatial purification device 1 according to a first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a side cross-sectional view showing the spatial purification device 1 according to the first embodiment. Fig. 2 is a top view showing the spatial purification device 1 of Fig. 1.

[0011] The space purification device 1 performs electrolysis of a first aqueous solution L1 containing chloride ions in an electrolytic cell 10 described below to generate and volatilize hypochlorous acid. The space purification device 1 removes bacteria, fungi, viruses, odors, and the like contained in the air in the external space of the space purification device 1 by causing the volatilized hypochlorous acid to flow out into the external space of a housing (not shown) that constitutes the space purification device 1.

[0012] 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 includes, for example, inside a so-called air conditioner, around an electric fan, around a circulator, around a ceiling fan, inside a humidifier, inside an air purifier, on a desk, etc.

[0013] As shown in FIGS. 1 and 2, the spatial purification device 1 includes an electrolytic cell 10, a first supply cell 20a, a second supply cell 20b, a first anion exchange membrane 30a, a second anion exchange membrane 30b, and a current control unit 40.

[0014] The electrolytic cell 10, the first supply cell 20a, the second supply cell 20b, the first anion exchange membrane 30a, the second anion exchange membrane 30b, and the current control unit 40 are housed in a housing (not shown). That is, the space purification device 1 may be a unit integrated into the housing. The shape of the housing may 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 housed inside an air conditioner, for example, about 10 cm x 7 cm x 4 cm.

[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 a state in which the first aqueous solution L1 is stored in the electrolytic cell 10. The first aqueous solution L1 is, for example, a dilute sodium chloride aqueous solution or a dilute potassium chloride aqueous solution having a predetermined chloride ion concentration.

[0016] The "predetermined chloride ion concentration" of the first aqueous solution L1 includes both a chloride ion concentration having a predetermined range of values ​​and a chloride ion concentration having a predetermined 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 1%. By setting the predetermined chloride ion concentration within the range or 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 first supply tank 20a is a tank for storing the second aqueous solution L2 containing hydroxide ions. The hydroxide ions contained in the second aqueous solution L2 in the first supply tank 20a pass through the first anion exchange membrane 30a and are supplied to the first aqueous solution L1 in the electrolytic cell 10. The electrolytic cell 10, the first supply tank 20a, and the first anion exchange membrane 30a described below may be collectively referred to as a "diaphragm-equipped electrolytic cell."

[0018] The first supply tank 20a is a tank for storing the second aqueous solution L2 containing hydroxide ions and supplying the hydroxide ions to the first aqueous solution L1. FIG. 1 shows a state in which the second aqueous solution L2 is stored in the first supply tank 20a. The second aqueous solution L2 is, for example, an aqueous sodium hydroxide solution. More specifically, the second aqueous solution L2 may be, for example, an aqueous sodium hydroxide solution having a mass percent concentration of 0.1% to 5%, or may be 1%. It is more preferable that the second aqueous solution L2 contains sodium chloride or potassium chloride so as to have the same molar concentration as the metal cations (sodium ions or potassium ions) contained in the first aqueous solution L1.

[0019] The second supply tank 20b is a tank for storing the third aqueous solution L3 containing chloride ions. The chloride ions contained in the third aqueous solution L3 in the second supply tank 20b permeate through the second anion exchange membrane 30b and are supplied to the first aqueous solution L1 in the electrolytic tank 10.

[0020] The second supply tank 20b is a tank for storing the third aqueous solution L3 containing chloride ions and supplying the chloride ions to the first aqueous solution L1. FIG. 1 shows a state in which the third aqueous solution L3 is stored in the second supply tank 20b. The chloride ion concentration of the third aqueous solution L3 is higher than that of the first aqueous solution L1. The third aqueous solution L3 is, for example, a high-concentration aqueous hydrochloric acid solution. More specifically, the third aqueous solution L3 is, for example, an aqueous hydrochloric acid solution having a mass percent concentration of 10% to 25%. It is more preferable that the third aqueous solution L3 contains sodium chloride or potassium chloride at the same mass percent concentration (=mass percent concentration relative to the solvent mass excluding the hydrochloric acid mass contained in the third aqueous solution L3) as that of sodium chloride or potassium chloride contained in the first aqueous solution L1. In other words, it is preferable that the third aqueous solution L3 contains metal cations (sodium ions or potassium ions) at the same molar concentration as that of the metal cations (sodium ions or potassium ions) contained in the first aqueous solution L1. In this case, the "same molar concentration" does not necessarily mean the same molar concentration, but may be a molar concentration that reduces the difference in concentration of metal cations (sodium ions or potassium ions) contained in the third aqueous solution L3 and the first aqueous solution L1. In this way, it is possible to suppress the phenomenon in which metal cations (sodium ions or potassium ions) contained in the first aqueous solution L1 permeate through the second anion exchange membrane 30b into the third aqueous solution L3 (this phenomenon occurs significantly when the difference in concentration of metal cations between the aqueous solutions passing through the anion exchange membrane is large).

[0021] Assuming continuous use for eight hours every day for a year, the respective volumes of the electrolytic cell 10 and the second supply cell 20b are preferably set so that, for example, the volume of the second supply cell 20b is at least about 12 times the volume of the electrolytic cell 10. By setting the volume ratio in this way, the second supply cell 20b can store the third aqueous solution L3 containing a sufficient amount of chloride ions required to be supplied to the first aqueous solution L1 of the electrolytic cell 10. Therefore, the amount of chloride ions stored in the electrolytic cell 10 can be reduced from the third aqueous solution L3 stored in the second supply cell 20b to the amount of chloride ions stored in the electrolytic cell 10. Chloride ions can be stably supplied to the first aqueous solution L1. The amount of the first aqueous solution L1 stored in the electrolytic bath 10 is, for example, about 2 mL to 10 mL. The volume of the first supply bath 20a is approximately the same as that of the electrolytic bath 10, and the amount of the second aqueous solution L2 stored in the first supply bath 20a is, for example, about 2 mL to 10 mL.

[0022] The first anion exchange membrane 30a is a membrane-like member that connects the electrolytic cell 10 and the first supply tank 20a in a manner that allows anions to pass therebetween, based on a voltage applied between the electrolytic cell 10 and the first supply tank 20a. More specifically, when a voltage is applied between the electrolytic cell side anode 11 and the first supply tank side cathode 12 described below, first membrane-type electrolysis is performed via the first anion exchange membrane 30a. By the first membrane-type electrolysis using the electrolytic cell side anode 11 and the first supply tank side cathode 12, hydroxide ions contained in the second aqueous solution L2 permeate the first anion exchange membrane 30a and are supplied to the first aqueous solution L1 (indicated by a thick black arrow in the positive direction of the x-axis).

[0023] The first anion exchange membrane 30a in this embodiment is not a type of anion exchange membrane through which anions permeate by osmotic pressure without using electricity. In addition, the first anion exchange membrane 30a does not allow sodium ions, which are cations, to permeate. More specifically, when hydroxide ions contained in the second aqueous solution L2 permeate the first anion exchange membrane 30a and are supplied to the first aqueous solution L1 by the first diaphragm electrolysis using the electrolytic cell side anode 11 and the first supply cell side cathode 12, sodium ions, which are cations, do not permeate the first anion exchange membrane 30a. The first anion exchange membrane 30a is, for example, a hydrocarbon-based anion exchange membrane, and includes membranes having the properties of monovalent anion selective permeability, alkali resistance, and high temperature resistance.

[0024] The first anion exchange membrane 30a is disposed between the electrolytic cell 10 and the first supply cell 20a. For example, the surface of the electrolytic cell 10 facing the first supply cell 20a (the yz plane on the negative side of the x-axis) and the surface of the first supply cell 20a facing the electrolytic cell 10 (the yz plane on the positive side of the x-axis) may each be formed of a frame-shaped member. When the surfaces of the electrolytic cell 10 and the first supply cell 20a facing each other are each formed of a frame-shaped member, the first anion exchange membrane 30a may be disposed so as to be fitted into the frame-shaped member.

[0025] The second anion exchange membrane 30b is a membrane-like member that connects the electrolytic cell 10 and the second supply cell 20b in a manner that allows anions to pass therebetween based on a voltage applied between the electrolytic cell 10 and the second supply cell 20b. More specifically, when a voltage is applied between the electrolytic cell side anode 11 and the second supply cell side cathode 21 described below, second membrane electrolysis is performed via the second anion exchange membrane 30b. By the second membrane electrolysis using the electrolytic cell side anode 11 and the second supply cell side cathode 21, chloride ions contained in the third aqueous solution L3 permeate the second anion exchange membrane 30b and are supplied to the first aqueous solution L1 (indicated by a thick black arrow in the negative direction of the x-axis).

[0026] The second anion exchange membrane 30b in this embodiment is not a type of anion exchange membrane through which anions permeate by osmotic pressure without using electricity. In addition, the second anion exchange membrane 30b does not allow sodium ions, which are cations, to permeate. More specifically, when chloride ions contained in the third aqueous solution L3 are permeated through the second anion exchange membrane 30b and supplied to the first aqueous solution L1 by the second diaphragm electrolysis using the electrolytic cell side anode 11 and the second supply cell side cathode 21, sodium ions, which are cations, do not permeate through the second anion exchange membrane 30b. The second anion exchange membrane 30b is, for example, a hydrocarbon-based anion exchange membrane, and includes membranes having the properties of monovalent anion selective permeability, alkali resistance, and high temperature resistance.

[0027] The second anion exchange membrane 30b is disposed between the electrolytic cell 10 and the second supply cell 20b. For example, the surface of the electrolytic cell 10 facing the second supply cell 20b (the yz plane on the positive side of the x-axis) and the surface of the second supply cell 20b facing the electrolytic cell 10 (the yz plane on the negative side of the x-axis) may each be formed of a frame-shaped member. When the second anion exchange membrane 30b is formed of a frame-shaped member, the second anion exchange membrane 30b may be disposed so as to be fitted into the frame-shaped member.

[0028] The current control unit 40 controls the current used in the first diaphragm electrolysis and the second diaphragm electrolysis. More specifically, the current control unit 40 controls the current used in the first diaphragm electrolysis performed through the first anion exchange membrane 30a using the electrolytic cell side anode 11 arranged in the electrolytic cell 10 and the first supply cell side cathode 12 arranged in the first supply cell 20a across the electrolytic cell 10 and the first supply cell side cathode 12 arranged in the first supply cell 20a. The current control unit 40 also controls the current used in the second diaphragm electrolysis performed through the second anion exchange membrane 30b using the electrolytic cell side anode 11 arranged in the electrolytic cell 10 and the second supply cell side cathode 21 arranged in the second supply cell 20b across the electrolytic cell 10 and the second supply cell side anode 11 arranged in the electrolytic cell 10 and the second supply cell side cathode 21 arranged in the second supply cell 20b. The electrolytic cell side anode 11 is used for both the first diaphragm electrolysis and the second diaphragm electrolysis. That is, the space purification device 1 according to this embodiment has one anode and two cathodes, a total of three electrodes. Since the first supply tank 20a and the second supply tank 20b are each equipped with only a cathode, chlorine is not generated in the first supply tank 20a and the second supply tank 20b by a chemical reaction to be described later.

[0029] Hereinafter, the details of each of the tanks (the electrolytic tank 10, the first supply tank 20a, and the second supply tank 20b) constituting the spatial purification device 1 will be described in more detail with reference to FIGS.

[0030] (electrolytic cell) The electrolytic cell 10 comprises an electrolytic cell-side anode 11 , wiring 13 , an inlet 15 , a mixing space 16 and an outlet 17 .

[0031] The electrolytic cell side anode 11 is an electrode used in electrolysis of the first aqueous solution L1 in combination with the first supply tank side cathode 12 disposed in the first supply tank 20a. As shown in FIG. 1, a first anion exchange membrane 30a is disposed between the electrolytic cell side anode 11 and the first supply tank side cathode 12. That is, the electrolysis of the first aqueous solution L1 and the second aqueous solution L2 performed using the pair of the electrolytic cell side anode 11 and the first supply tank side cathode 12 is membrane electrolysis (first membrane electrolysis). The first membrane electrolysis of the first aqueous solution L1 performed using the pair of the electrolytic cell side anode 11 and the first supply tank side cathode 12 produces hypochlorous acid used for space purification.

[0032] The electrolytic cell-side anode 11 has a plate-like shape. That is, the electrolytic cell-side anode 11 is an anode plate having a plate-like shape and arranged on the electrolytic cell 10 side. The plate-like shape includes a rectangular shape or an oblong shape. Hereinafter, the electrolytic cell-side anode 11 may also be referred to as an "electrolytic cell-side anode plate."

[0033] As an example, a case where the plate shape of the electrolytic cell-side anode 11 is rectangular will be described. As shown in Fig. 1, the electrolytic cell-side anode 11 is arranged such that the short side direction of the rectangle is along the vertical direction (z-axis direction). This arrangement can prevent bubbles generated by chemical reactions from adhering to both sides of the rectangular shape of the electrode. Furthermore, compared to a case where the long side direction of the rectangle is arranged along the vertical direction (z-axis direction), when the short side direction is arranged along the vertical direction (z-axis direction), it is possible to prevent bubbles generated at the lower part (negative side of the z-axis) of the electrolytic cell-side anode 11 from adhering to the upper part (positive side of the z-axis) of the electrolytic cell-side anode 11.

[0034] 2, the electrolytic cell side anode 11 is arranged such that the longitudinal direction of the rectangle is along the horizontal direction (y-axis direction). The first supply tank side cathode 12 is arranged in a similar manner, as will be described in detail later. In other words, the electrolytic cell side anode 11 and the first supply tank side cathode 12 are arranged such that the planes (yz planes) of the respective rectangles face each other with a predetermined interval therebetween. The predetermined interval is an interval suitable for electrolysis performed using a pair of the electrolytic cell side anode 11 and the first supply tank side cathode 12.

[0035] The electrolytic cell-side anode 11 includes an electrolytic cell-side anode plate immersion portion 11a and an electrolytic cell-side anode plate protruding portion 11b.

[0036] The electrolytic cell-side anode 11 is inserted from the outside of the electrolytic cell 10 toward the inside. In FIG. 2, as an example, the electrolytic cell-side anode 11 is inserted from the side of the electrolytic cell 10 (the xz plane side on the y-axis negative side) toward the horizontal direction (y-axis direction). The electrolytic cell-side anode plate immersed portion 11a inserted into the electrolytic cell 10 is a portion of the electrolytic cell-side anode 11 that is disposed on the inside side of the electrolytic cell 10 and is 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 entirety of the electrolytic cell-side anode plate immersed portion 11a is 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 end (the end on the z-axis positive side) of the electrolytic cell-side anode plate immersed portion 11a.

[0037] The electrolytic cell-side anode plate protrusion 11b is a portion of the electrolytic cell-side anode 11 that is disposed on the external side of the electrolytic cell 10. The wiring 13 is a line through which a current flows. The electrolytic cell-side anode plate protrusion 11b is electrically connected to a current control unit 40 via the wiring 13.

[0038] As the electrolytic cell side anode 11, for example, a platinum iridium titanium electrode, a platinum electrode, a ruthenium titanium electrode, an iridium titanium oxide electrode, or the like may be used.

[0039] The inlet 15 is an opening through which air from the external space of the housing constituting the space purification device 1 flows in. That is, the inlet 15 is an opening through which air from the external space of the space purification device 1 flows in. In FIG. 1, the inlet 15 is provided on the upper surface (xy plane on the z-axis positive side) of the electrolytic cell 10 as an example, but it is sufficient that the inlet 15 is located above the liquid level S1 of the first aqueous solution L1. The shape of the inlet 15 may be, for example, cylindrical as shown in FIG. 2, or may be a square tube.

[0040] The mixing space 16 is a space formed on the upper side (z-axis positive side) of the electrolytic cell 10 in a state where the first aqueous solution L1 is stored in the electrolytic cell 10. The mixing space 16 is a space for mixing hypochlorous acid generated by the first diaphragm electrolysis of the first aqueous solution L1 performed using a pair of the electrolytic cell side anode 11 and the first supply cell side cathode 12 with the air of the external space flowing in from the inlet 15. The hypochlorous acid generated by the first diaphragm electrolysis includes hypochlorous acid gas that has been volatilized and gasified, and hypochlorous acid dissolved in the first aqueous solution L1. The hypochlorous acid gas is contained in the air that flows in from the inlet 15 and flows out to the external space from the outlet 17 described later. The hypochlorous acid dissolved in the first aqueous solution L1 flows out to the external space from the outlet 17 described later by gas-liquid contact with the air that flows in from the inlet 15.

[0041] The outlet 17 is an opening through which the mixed air, which is a mixture of the air flowing in from the inlet 15 and the hypochlorous acid generated by the first diaphragm electrolysis of the first aqueous solution L1, flows out to the external space of the housing. That is, the outlet 17 is an opening through which the mixed air flows out to the external space of the space purification device 1. In FIG. 1, the outlet 17 is provided on the upper surface (xy plane on the z-axis positive side) of the electrolytic cell 10 as an example, similar to the inlet 15, but it may be located above the liquid level of the first aqueous solution L1. The shape of the outlet 17 is similar to that of the inlet 15, and may be, for example, cylindrical as shown in FIG. 2, or may be rectangular.

[0042] The inlet 15 and the outlet 17 may be provided with a cover (not shown) that can be opened or closed or that can be attached or detached. The cover may be configured to be in a closed state when the space purification device 1 is transported or moved, and to be opened or detached when the space purification device 1 is used. In addition, although the inlet 15 and the outlet 17 are described as having separate configurations, the inlet 15 and the outlet 17 may each serve as both an inlet and an outlet depending on the direction of the wind flowing into the space purification device 1.

[0043] The air containing hypochlorous acid that flows out from the outlet 17 into the space outside the space purification device 1 purifies the space of the outside space. That is, the air containing hypochlorous acid removes bacteria, fungi, viruses, odors, and the like contained in the air in the space outside the housing.

[0044] (1st supply tank) The first supply tank 20a includes a first supply tank side cathode 12, a wiring 14, and a first exhaust port 23a.

[0045] The first supply tank side cathode 12 is an electrode used in combination with the electrolytic cell side anode 11 for electrolysis of the second aqueous solution L2. As described above, a first anion exchange membrane 30a is disposed between the first supply tank side cathode 12 and the electrolytic cell side anode 11. That is, the electrolysis of the second aqueous solution L2 performed using the pair of the first supply tank side cathode 12 and the electrolytic cell side anode 11 is membrane electrolysis (first membrane electrolysis). The first membrane electrolysis of the second aqueous solution L2 performed using the pair of the first supply tank side cathode 12 and the electrolytic cell side anode 11 generates hydroxide ions and supplies hydroxide ions from the second aqueous solution L2 to the first aqueous solution L1. In addition, hydrogen is generated by the first membrane electrolysis of the second aqueous solution L2 performed using the pair of the first supply tank side cathode 12 and the electrolytic cell side anode 11.

[0046] The first supply tank side cathode 12 has a plate-like shape, similar to the electrolytic tank side anode 11. That is, the first supply tank side cathode 12 is a cathode plate having a plate-like shape and arranged on the first supply tank 20a side. The plate-like shape includes a rectangular shape or an oblong shape. Hereinafter, the first supply tank side cathode 12 may also be referred to as a "first supply tank side cathode plate."

[0047] As an example, a case will be described in which the plate shape of the first supply tank side cathode 12 is rectangular, the same as that of the electrolytic tank side anode 11. As shown in FIG. 1, the first supply tank side cathode 12 is arranged such that the short side direction of the rectangle is along the vertical direction (z-axis direction). This arrangement can prevent bubbles generated by chemical reactions from adhering to both sides of the rectangle of the electrode. Furthermore, compared to a case in which the long side direction of the rectangle is arranged along the vertical direction (z-axis direction), when the short side direction is arranged along the vertical direction (z-axis direction), it is possible to prevent bubbles generated at the lower part (negative side of the z-axis) of the first supply tank side cathode 12 from adhering to the upper part (positive side of the z-axis) of the first supply tank side cathode 12.

[0048] 2, the first supply tank side cathode 12 is disposed such that the longitudinal direction of the rectangle is along the horizontal direction (y-axis direction). The first supply tank side cathode 12 and the electrolytic cell side anode 11 are disposed such that their rectangular planes (yz planes) face each other with a predetermined interval between them. The predetermined interval is an interval suitable for electrolysis performed using a pair of the electrolytic cell side anode 11 and the first supply tank side cathode 12.

[0049] The electrolytic cell side anode 11 and the first supply tank side cathode 12 are each in close proximity to the first anion exchange membrane 30a. In this specification, "in close proximity" includes both a state in which the electrolytic cell side anode 11 and the first supply tank side cathode 12 are in close proximity to the first anion exchange membrane 30a with a predetermined gap therebetween, and a state in which the electrolytic cell side anode 11 and the first supply tank side cathode 12 are in contact with the first anion exchange membrane 30a.

[0050] The plane of the rectangular plate on the first anion exchange membrane 30a side of the electrolytic cell side anode 11 (yz plane on the negative x-axis side) is defined as plane P1. The plane of the rectangular plate on the first anion exchange membrane 30a side of the first supply tank side cathode 12 (yz plane on the positive x-axis side) is defined as plane P2. The planes P1 and P2 are disposed opposite each other via the first anion exchange membrane 30a. This arrangement allows a uniform electric field to be generated between the electrolytic cell side anode 11 and the first supply tank side cathode 12.

[0051] The first supply tank side cathode 12 includes a first supply tank side cathode plate immersion portion 12a and a first supply tank side cathode plate protrusion portion 12b. The first supply tank side cathode 12 is inserted from the outside of the first supply tank 20a toward the inside. In FIG. 2, as an example, the first supply tank side cathode 12 is inserted from the side (the xz plane side on the y-axis negative side) of the first supply tank 20a toward the horizontal direction (y-axis direction) like the electrolytic tank side anode 11. The first supply tank side cathode plate immersion portion 12a inserted into the first supply tank 20a is a portion of the first supply tank side cathode 12 that is disposed on the inside side of the first supply tank 20a and is entirely immersed in the second aqueous solution L2. In other words, the second aqueous solution L2 is stored in the first supply tank 20a so that the entire first supply tank side cathode plate immersion portion 12a is immersed. That is, the second aqueous solution L2 is stored in the first supply tank 20a so that the liquid level S2 of the second aqueous solution L2 exceeds the upper end (the end on the z-axis positive side) of the first supply tank side cathode plate immersed portion 12a.

[0052] The first supply tank side cathode plate protrusion 12b is a portion of the first supply tank side cathode 12 that is disposed on the outside side of the first supply tank 20a. The wiring 14 is a line through which a current flows. The first supply tank side cathode plate protrusion 12b is electrically connected to a current control unit 40 via the wiring 14.

[0053] As the first supply tank side cathode 12, for example, a platinum iridium titanium electrode, a platinum electrode, a ruthenium titanium electrode, an iridium titanium oxide electrode, or the like may be used.

[0054] The first exhaust port 23a is an opening for discharging hydrogen gas generated by the first diaphragm electrolysis of the second aqueous solution L2 to the external space of the housing. The first exhaust port 23a may be, for example, a check valve. When a check valve is used as the first exhaust port 23a, hydrogen gas inside the first supply tank 20a is discharged to the external space, but the inflow of gas such as air from the external space can be suppressed. When the first diaphragm electrolysis of the second aqueous solution L2 is repeated, hydrogen gas accumulates inside the first supply tank 20a, and the internal pressure of the first supply tank 20a increases. The pressure opens the check valve, and hydrogen gas is discharged to the external space of the first supply tank 20a.

[0055] (2nd supply tank) The second supply tank 20b includes a second supply tank side cathode 21, a wiring 22, and a second outlet 23b.

[0056] The second supply tank side cathode 21 is an electrode used in combination with the electrolytic cell side anode 11 for electrolysis of the third aqueous solution L3. As shown in FIG. 1, a second anion exchange membrane 30b is disposed between the electrolytic cell side anode 11 and the second supply tank side cathode 21. That is, the electrolysis of the third aqueous solution L3 performed using the pair of the electrolytic cell side anode 11 and the second supply tank side cathode 21 is membrane electrolysis (second membrane electrolysis). That is, the electrolytic cell side anode 11 is used for both the first membrane electrolysis and the second membrane electrolysis. Chloride ions are supplied from the third aqueous solution L3 to the first aqueous solution L1 by the second membrane electrolysis of the third aqueous solution L3 performed using the pair of the electrolytic cell side anode 11 and the second supply tank side cathode 21. Also, hydrogen is generated by the second membrane electrolysis of the third aqueous solution L3 performed using the pair of the electrolytic cell side anode 11 and the second supply tank side cathode 21.

[0057] The second supply tank side cathode 21 has a plate-like shape, similar to the electrolytic tank side anode 11 and the first supply tank side cathode 12. That is, the second supply tank side cathode 21 is a cathode plate having a plate-like shape and arranged on the second supply tank 20b side. The plate-like shape includes a rectangular shape or a rectangular shape. Hereinafter, the second supply tank side cathode 21 may also be referred to as a "second supply tank side cathode plate."

[0058] As an example, a case will be described where the second supply tank side cathode 21 also has a rectangular plate shape, similar to the electrolytic tank side anode 11 and the first supply tank side cathode 12. As shown in Fig. 1, the second supply tank side cathode 21 is disposed such that the shorter side direction of the rectangle is aligned along the vertical direction (z-axis direction). Further, the second supply tank side cathode 21 is disposed so that the longitudinal direction of the rectangle is aligned in the horizontal direction (y-axis direction).

[0059] The electrolytic cell side anode 11 and the second supply tank side cathode 21 are each close to the second anion exchange membrane 30b. In this specification, "close to" includes both a state in which the electrolytic cell side anode 11 and the second supply tank side cathode 21 are close to the second anion exchange membrane 30b with a predetermined gap therebetween, and a state in which the electrolytic cell side anode 11 and the second supply tank side cathode 21 are in contact with the second anion exchange membrane 30b.

[0060] The plane of the plate-like rectangle on the second anion exchange membrane 30b side of the electrolytic cell side anode 11 (yz plane on the x-axis positive side) is defined as plane P3. The plane of the plate-like rectangle on the second anion exchange membrane 30b side of the second supply tank side cathode 21 (yz plane on the x-axis negative side) is defined as plane P4. The planes P3 and P4 are arranged opposite to each other via the second anion exchange membrane 30b. This arrangement allows a uniform electric field to be generated between the electrolytic cell side anode 11 and the second supply tank side cathode 21.

[0061] The second supply tank side cathode 21 includes a second supply tank side cathode plate immersed portion 21a and a second supply tank side cathode plate protruding portion 21b. The second supply tank side cathode 21 is inserted from the outside of the second supply tank 20b toward the inside. In FIG. 2, as an example, the second supply tank side cathode 21 is inserted from the side of the second supply tank 20b (the xz plane side on the y-axis negative side) toward the horizontal direction (y-axis direction). The second supply tank side cathode plate immersed portion 21a inserted into the second supply tank 20b is a portion of the second supply tank side cathode 21 that is disposed on the inside side of the second supply tank 20b and is entirely immersed in the third aqueous solution L3. In other words, the third aqueous solution L3 is stored in the second supply tank 20b so that the entire second supply tank side cathode plate immersed portion 21a is immersed. That is, the third aqueous solution L3 is stored in the second supply tank 20b so that the liquid level S3 of the third aqueous solution L3 exceeds the upper end (the end on the z-axis positive side) of the second supply tank side cathode plate immersed portion 21a.

[0062] 2, the second supply tank side cathode plate protrusion 21b is a portion of the second supply tank side cathode 21 that is disposed on the outside side of the second supply tank 20b. The wiring 22 is a line through which a current flows. The second supply tank side cathode plate protrusion 21b is electrically connected to the current control unit 40 via the wiring 22.

[0063] As the second supply tank side cathode 21, for example, a platinum iridium titanium electrode, a platinum electrode, a ruthenium titanium electrode, an iridium titanium oxide electrode, or the like may be used.

[0064] The second outlet 23b is an opening for discharging hydrogen gas generated by the second diaphragm electrolysis of the third aqueous solution L3 to the external space of the housing. The second outlet 23b may be, for example, a check valve. When a check valve is used as the second outlet 23b, hydrogen gas in the second supply tank 20b is discharged to the external space, but the inflow of gas such as air from the external space can be suppressed. When the second diaphragm electrolysis of the third aqueous solution L3 is repeated, hydrogen gas accumulates inside the second supply tank 20b, and the internal pressure of the second supply tank 20b increases. The pressure opens the check valve, and hydrogen gas is discharged to the external space of the second supply tank 20b.

[0065] As shown in Fig. 1, the spatial purification device 1 may further include a water level detection unit 18 and a water supply unit 19. The water level detection unit 18 detects the position of the liquid level S1 in the first aqueous solution L1. The water level detection unit 18 is, for example, a water level sensor. The water level detection unit 18 is disposed at least above (on the positive side of the z-axis) the upper end (the part on the positive side of the z-axis) of the electrolytic cell-side anode plate immersed part 11a.

[0066] The water supply unit 19 supplies water to the electrolytic cell 10 based on the position of the liquid level S1 detected by the water level detection unit 18. More specifically, the upper end (the part on the positive side of the z-axis) of the electrolytic cell-side anode plate immersed part 11a The water level supply unit 19 supplies water to the electrolytic cell 10 so that the water level does not fall below this level. The water supply unit 19 may be, for example, a Peltier element that can cool and condense moisture contained in the air into water droplets, or a water tank that can store water. The water supply unit 19 may be located at a position where it can supply water to the electrolytic cell 10, and may be located on the upper side of the electrolytic cell 10 or on the upper side of the second supply cell 20b as shown in FIG. 1.

[0067] When the spatial purification device 1 includes the water level detection unit 18 and the water supply unit 19, the electrolytic cell-side anode plate immersed part 11a can be maintained immersed in the first aqueous solution L1. This prevents the electrolytic cell-side anode plate immersed part 11a from being exposed to air due to a decrease in the first aqueous solution L1, and maintains the electrolysis efficiency of the first diaphragm electrolysis.

[0068] 1 and 2, the spatial purification device 1 according to this embodiment includes a first diaphragm electrolysis unit E1 and a second diaphragm electrolysis unit E2. The current control unit 40 controls a first current flowing through the first diaphragm electrolysis unit E1 and a second current flowing through the second diaphragm electrolysis unit E2, thereby controlling the chemical reaction occurring in the first diaphragm electrolysis unit E1 and the chemical reaction occurring in the second diaphragm electrolysis unit E2.

[0069] The first membrane-containing electrolysis unit E1 is provided between the electrolytic cell 10 and the first supply cell 20a. The first membrane-containing electrolysis unit E1 performs first membrane-containing electrolysis via the first anion exchange membrane 30a by passing a first current between the electrolytic cell-side anode 11 and the first supply cell-side cathode 12. More specifically, the first membrane-containing electrolysis unit E1 performs membrane-containing electrolysis of the first aqueous solution L1 to produce hypochlorous acid and performs membrane-containing electrolysis of the second aqueous solution L2 to produce hydroxide ions and hydrogen by passing a first current between the electrolytic cell-side anode 11 and the first supply cell-side cathode 12. In other words, the first membrane-containing electrolysis unit E1 includes the electrolytic cell-side anode 11, the first supply cell-side cathode 12, and the first anion exchange membrane 30a.

[0070] The second membrane-containing electrolysis unit E2 is provided across the electrolytic cell 10 and the second supply cell 20b. A second current is passed between the electrolytic cell side anode 11 and the second supply cell side cathode 21 to perform membrane-containing electrolysis via the second anion exchange membrane 30b. More specifically, the second membrane-containing electrolysis unit E2 performs membrane-containing electrolysis of the third aqueous solution L3 to produce hydrogen by passing a second current between the electrolytic cell side anode 11 and the second supply cell side cathode 21. In other words, the second membrane-containing electrolysis unit E2 includes the electrolytic cell side anode 11, the second supply cell side cathode 21, and the second anion exchange membrane 30b.

[0071] Here, with reference to Fig. 3 and Fig. 4, the details of the chemical reaction occurring in the first diaphragm electrolysis unit E1 provided between the electrolytic cell 10 and the first supply cell 20a, and the chemical reaction occurring in the second diaphragm electrolysis unit E2 provided between the electrolytic cell 10 and the second supply cell 20b will be described. Fig. 3 and Fig. 4 are diagrams showing the formulas of the respective chemical reactions occurring in the first diaphragm electrolysis unit E1 and the second diaphragm electrolysis unit E2 constituted by the respective cells of the spatial purification device 1. Note that, hereinafter, a case will be described in which the first aqueous solution L1 containing chloride ions is a sodium chloride aqueous solution, the second aqueous solution L2 containing hydroxide ions is a sodium hydroxide aqueous solution, and the third aqueous solution L3 containing chloride ions is a hydrochloric acid aqueous solution.

[0072] [First diaphragm electrolytic section E1 (electrolytic cell 10 & first supply tank 20a)] The sodium chloride (NaCl) contained in the sodium chloride aqueous solution, which is the first aqueous solution L1, is + and Cl - The sodium hydroxide (NaOH) contained in the second aqueous solution L2 is ionized as Na + and OH - When a predetermined voltage is applied to the first membrane electrolysis section E1, a current flows, electrons move, and the following chemical reaction shown in FIG.

[0073] Reaction formula (a): Equation in which chlorine is generated from chloride ions at the electrolytic cell anode 11 Reaction formula (b): Hydrogen and hydroxide ions are generated from water at the cathode 12 on the first supply tank side. Reaction formula (c): Water and oxygen are generated from hydroxide ions at the electrolytic cell anode 11. Reaction formula (d): The reaction formula for the generation of hydrochloric acid and hypochlorous acid from chlorine and water in the first aqueous solution L1 Reaction formula (e): Hypochlorous acid generation reaction at the electrolytic cell anode 11 (=Reaction formula (a) + Reaction formula (d)) Reaction formula (f): Reaction formula for consuming electrons and permeating the second anion exchange membrane 30b to supply chloride ions to the electrolytic cell 10 A voltage is applied to the first membrane electrolysis unit E1 to flow a current, and the first aqueous solution L1 stored in the electrolysis cell 10 is converted into electrons (e - When one of the anion exchange membranes is lost, chloride ions Cl are transferred from the third aqueous solution L3 stored in the second supply tank 20b through the second anion exchange membrane 30b to the first aqueous solution L1 in the electrolytic tank 10. - is supplied.

[0074] Meanwhile, the reaction formula (c) of the first diaphragm electrolysis progresses, and the first aqueous solution L1 stored in the electrolytic cell 10 converts into hydroxide ions (OH - When one of the anion exchange membranes 30a and 30b is consumed, hydroxide ions OH - At this time, in the first supply tank 20a, hydroxide ions OH - is produced according to reaction (b).

[0075] Here, the ratio of the current used in the hypochlorous acid generation reaction in reaction formula (e) is "x", and the ratio of the current used in the oxygen generation reaction in reaction formula (c) is "1-x". The ratio of the current used in reaction formula (b) of the first diaphragm electrolysis is "y", and the ratio of the current used in reaction formula (f) of the second diaphragm electrolysis is "1-y". Applying the above x and y to reaction formula (b) + (c) + (e) + (f), the following reaction formula (g) is obtained.

[0076] Reaction (g): The reaction equation derived from reaction (b)+(c)+(e)+(f) When membrane electrolysis is performed in the first membrane electrolysis unit E1, chloride ions in the electrolytic cell 10 are consumed and therefore reduced, but in the space purification device 1 according to this embodiment, chloride ions are supplied from the third aqueous solution L3 stored in the second supply tank 20b to the first aqueous solution L1 stored in the electrolytic cell 10. On the other hand, when membrane electrolysis is performed in the first membrane electrolysis unit E1, hydroxide ions in the electrolytic cell 10 are consumed and therefore reduced, but in the space purification device 1 according to this embodiment, hydroxide ions are supplied from the second aqueous solution L2 stored in the first supply tank 20a to the first aqueous solution L1 stored in the electrolytic cell 10.

[0077] Here, the amount of chloride ions (Cl ) consumed by the first diaphragm electrolysis is transferred from the third aqueous solution L3 stored in the second supply tank 20b to the first aqueous solution L1 stored in the electrolytic tank 10. - ) is supplied to the electrolytic cell 10, and Cl - The conditions under which there is no apparent increase or decrease are as shown in Figure 4. In this reaction, hypochlorous acid (HClO) evaporates as a gas, so it is not included in the following formula.

[0078] Reaction formula (h): Cl - A conditional expression that does not appear to increase or decrease After transformation, this gives reaction equation (i) shown in FIG.

[0079] Reaction (i): A modification of reaction (h) Substituting y into the above reaction formula (g) gives reaction formula (j) shown in FIG.

[0080] Reaction (j): Reaction (g) + (i) After transformation, the following reaction equation (k) is obtained.

[0081] Reaction equation (k): A transformation of reaction equation (j) According to reaction formula (k) shown in Figure 4, for example, when two electrons flow to the first diaphragm electrolysis unit E1, one hypochlorous acid (HClO) is generated. For example, when four electrons flow to the first diaphragm electrolysis unit E1, one oxygen is generated. For example, when two electrons flow to the first diaphragm electrolysis unit E1, one hydrogen is generated.

[0082] In addition, since the acid dissociation constant of hypochlorous acid (HClO) is about 7.5, it is necessary to maintain the pH of the first aqueous solution L1 unchanged. In reaction formula (k) shown in FIG. 4, 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 2 ) consumed by the first diaphragm electrolysis is transferred from the third aqueous solution L3 stored in the second supply tank 20b to the first aqueous solution L1 stored in the electrolytic cell 10. - ) is supplied to the electrolytic cell 10, and Cl - 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.

[0083] When the number of electrons flowing through the first diaphragm electrolysis unit E1 changes as described above, that is, when the ratio of the current flowing through the first diaphragm electrolysis unit E1 and the current flowing through the second diaphragm electrolysis unit E2 changes, the supply amount of chloride ions supplied from the second supply tank 20b to the electrolytic cell 10 changes. For example, when the ratio of the current used for the first diaphragm electrolysis changes from the current used for the chloride ions (Cl - ) is supplied to the electrolytic cell 10. - When the current ratio is greater than the condition where the current does not apparently increase or decrease (reaction formula (l) shown in FIG. 4), the Cl - The supply of Cl in the electrolytic cell 10 decreases. - decreases.

[0084] Cl in electrolytic cell 10 - When the electrolysis efficiency of the first membrane electrolysis is continued in a state where the electrolysis efficiency is decreased, the Cl in the electrolytic cell 10 gradually decreases. - increases, and Cl in the electrolytic cell 10 - reaches a level that appears to be no longer increasing or decreasing.

[0085] On the other hand, the amount of current used in the first diaphragm electrolysis is increased by 100% by supplying chloride ions (Cl - ) is supplied to the electrolytic cell 10. - When the current amount is larger than the condition under which the current does not apparently increase or decrease (reaction formula (m) shown in FIG. 4), the Cl - The supply of Cl in the electrolytic cell 10 increases. - increases.

[0086] Cl in electrolytic cell 10 - When the electrolysis efficiency of the first membrane electrolysis is increased, the electrolysis efficiency of the first membrane electrolysis is increased. When the first membrane electrolysis is continued in a state where the electrolysis efficiency is increased, the Cl in the electrolytic cell 10 gradually increases. - decreases, and Cl in the electrolytic cell 10 - reaches a level that appears to be no longer increasing or decreasing.

[0087] In addition, Cl in the electrolytic cell 10 - When the amount of Cl in the electrolytic cell 10 increases, the equilibrium of the reaction formula (d) shown in FIG. 3 shifts to the left, and the amount of chlorine generated increases. - By adjusting the current passed through the first membrane electrolysis unit E1 and the current passed through the second membrane electrolysis unit E2 so that the apparent increase or decrease in current does not occur, hypochlorous acid can be produced while suppressing the generation of chlorine.

[0088] [Second diaphragm electrolysis section E2 (electrolytic cell 10 & second supply tank 20b)] The reaction in the second supply tank 20b will be described. The only electrode arranged in the second supply tank 20b is the second supply tank side cathode 21. When a predetermined voltage is applied to the second membrane-containing electrolysis section E2, a current flows, electrons move, and the following chemical reaction shown in FIG. 4 occurs.

[0089] Reaction formula (n): Equation by which hydrogen and hydroxide ions are generated from water at the cathode 12 on the first supply tank side Reaction formula (o): A formula for consuming (supplying) chloride ions from the second supply tank 20b through the second anion exchange membrane 30b and obtaining electrons. When a voltage is applied to the second membrane electrolysis unit E2 and a current flows therethrough, the chloride ions (Cl - ) permeates through the second anion exchange membrane 30b and is supplied to the first aqueous solution L1, and the third aqueous solution L3 is supplied with electrons (e - ) 1

[0090] The above is the details of the chemical reaction that occurs in the first membrane electrolysis section E1 provided between the electrolytic cell 10 and the first supply cell 20a, and the chemical reaction that occurs in the second membrane electrolysis section E2 provided between the electrolytic cell 10 and the second supply cell 20b.

[0091] The current control unit 40 controls the above chemical reaction. More specifically, the second current is controlled so as to replenish the chloride ions contained in the first aqueous solution L1 that have been reduced by the membrane electrolysis in the first membrane electrolysis unit E1. By controlling the second current, the chloride ions contained in the third aqueous solution L3 are permeated through the second anion exchange membrane 30b and supplied to the first aqueous solution L1. Details will be described below with reference to FIG. 5.

[0092] 5 is a block diagram showing the current control unit 40 according to the embodiment 1. As shown in FIG.

[0093] The voltage acquiring unit 41 acquires a voltage between the electrolytic cell side anode 11 and the first supply cell side cathode 12. The voltage acquiring unit 41 is, for example, a voltmeter. The calculation unit 42 calculates the conductivity of the first aqueous solution L1 based on the voltage acquired by the voltage acquiring unit 41. The estimation unit 43 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 42.

[0094] The current control unit 40 controls the first current passed through the first membrane electrolysis unit E1 and the second current passed through the second membrane electrolysis unit E2 shown in Fig. 5 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.

[0095] [1. When the first and second currents flow simultaneously] When the current control unit 40 causes the first current and the second current to flow simultaneously, 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 43 is lower than a predetermined concentration: the current ratio of the first current and the second current is changed so as to increase the amount of chloride ions that permeate from the third aqueous solution L3 through the second anion exchange membrane 30b 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 43 is higher than a predetermined concentration: the current ratio of the first current and the second current is changed so as to reduce the amount of chloride ions that permeate from the third aqueous solution L3 through the second anion exchange membrane 30b 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 43 is a predetermined concentration: the current ratio of the first current to the second current is not changed.

[0096] [2. When the first current flows at a specified 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, the current control unit 40 performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is lower than a predetermined concentration: a second current is passed so as to increase the amount of chloride ions that permeate from the third aqueous solution L3 through the second anion exchange membrane 30b 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 43 is higher than a predetermined concentration: the second current is stopped so that the supply of chloride ions from the third aqueous solution L3 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 43 is a predetermined concentration: The first and second currents are not changed.

[0097] [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 43 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 permeate from the third aqueous solution L3 through the second anion exchange membrane 30b 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 43 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 third aqueous solution L3 to the first aqueous solution L1. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is a predetermined concentration: the first current and the second current are not changed.

[0098] As described above, the current control unit 40 controls the first current and the second current, so that the necessary 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.

[0099] In the above "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. Since 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 is minimized, and it is possible to maintain the concentration at an optimal predetermined level.

[0100] In the case of "2. When the first current is passed at a predetermined value while the second current is controlled at the same time," when there is an increase or decrease in the chloride ion concentration in the first aqueous solution L1, mainly the second current is passed or stopped. In the case of "3. When the first current or the second current is passed," when there is an increase or decrease in the chloride ion concentration in the first aqueous solution L1, one of the first current and the second current is passed and the other is stopped. Therefore, the chloride ion concentration in the first aqueous solution L1 can be maintained at a predetermined concentration. In the above cases 2 and 3, it is only necessary to control either the first current or the second current, so current control is easy.

[0101] As described above, the chloride ions consumed by the first aqueous solution L1 can be appropriately supplied from the third aqueous solution L3, so that it is possible to provide the space purification device 1 capable of stably generating a desired amount of hypochlorous acid gas. Therefore, it is possible to provide the space purification device 1 capable of stably generating 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.

[0102] Note that a plurality of current control units 40 may be provided to control the first current and the second current separately.

[0103] In addition, in FIG. 2, the inlet 15 and the outlet 17 are arranged on the lower right side (y-axis negative side and x-axis positive side) and the upper left side (y-axis positive side and x-axis negative side) when the electrolytic cell 10 is viewed in a plane, but the arrangement is not limited to this. For example, the positions of the inlet 15 and the outlet 17 may be reversed, the inlet 15 and the outlet 17 may be at the same position on the x-axis, or the inlet 15 and the outlet 17 may be at the same position on the y-axis. However, when the inlet 15 and the outlet 17 are arranged, it is preferable to arrange them so that they are at the farthest positions on the xy plane. With such an arrangement, the time during which the inflowing air and hypochlorous acid are mixed in the mixing space 16 is longer, so that more hypochlorous acid can be contained in the mixed air.

[0104] In addition, the plane P1 (yz plane on the negative side of the x-axis) of the rectangular plate on the first anion exchange membrane 30a side of the electrolytic cell side anode 11 and the plate on the first anion exchange membrane 30a side of the first supply cell side cathode 12 are A case will be described in which planes P2 (yz plane on the x-axis positive side) of the shaped rectangles do not face each other. When the planes of the rectangles are arranged parallel to the xy plane, a non-uniform electric field may be generated between the electrolytic cell side anode 11 and the first supply cell side cathode 12. When a non-uniform electric field is generated between the electrolytic cell side anode 11 and the first supply cell side cathode 12, the distribution of current between the electrolytic cell side anode 11 and the first supply cell side cathode 12 also becomes non-uniform.

[0105] When the distribution of the current between the electrolytic cell side anode 11 and the first supply tank side cathode 12 becomes non-uniform, regions with high and low current densities are generated. In the parts with high current density, the deterioration of the catalytic layer on the surfaces of the electrolytic cell side anode 11 and the first supply tank side cathode 12 (hereinafter also referred to as each electrode plate) is likely to progress, and in the parts with low current density, the deterioration of the catalytic layer on the surfaces of each electrode plate is unlikely to progress. That is, when a non-uniform electric field occurs between the electrolytic cell side anode 11 and the first supply tank side cathode 12, the distribution of the current becomes non-uniform, and regions with different current densities may exist simultaneously on the same electrode plate. Therefore, the deterioration of the catalytic layer due to the use of each electrode plate may occur non-uniformly. If the degree of deterioration of the catalytic layer on the surface of each electrode plate differs, when electrolysis is repeatedly performed, at a certain point, there may be a region on each electrode plate that can be used as an electrode and a region that cannot be used as a result of the deterioration. When electrolysis is performed with each electrode plate including a region that cannot be used as an electrode, there is a risk that the electrolysis efficiency is likely to decrease.

[0106] In contrast, in the spatial purification device 1 according to the present embodiment, the plane P1 and the plane P2 are arranged to face each other with the first anion exchange membrane 30a interposed therebetween. This arrangement allows a uniform electric field to be generated between the electrolytic cell side anode 11 and the first supply cell side cathode 12, and the current between the two electrodes is also uniformly distributed. Therefore, the deterioration of the catalyst layer on the surface of each electrode plate occurs uniformly, so that even when electrolysis is performed repeatedly, uneven deterioration of the catalyst layer on the surface of each electrode plate caused by an uneven electric field can be suppressed. Therefore, the decrease in electrolysis efficiency can be suppressed.

[0107] Similarly, when the distribution of current between the electrolytic cell side anode 11 and the second supply tank side cathode 21 becomes non-uniform, regions with high and low current densities are generated. In the parts with high current density, the deterioration of the catalytic layer on the surfaces of the electrolytic cell side anode 11 and the second supply tank side cathode 21 (hereinafter also referred to as each electrode plate) is likely to progress, and in the parts with low current density, the deterioration of the catalytic layer on the surface of each electrode plate is unlikely to progress. That is, when a non-uniform electric field occurs between the electrolytic cell side anode 11 and the second supply tank side cathode 21, the distribution of current becomes non-uniform, and regions with different current densities may exist simultaneously on the same electrode plate. Therefore, the deterioration of the catalytic layer due to the use of each electrode plate may occur non-uniformly. If the degree of deterioration of the catalytic layer on the surface of each electrode plate differs, when electrolysis is repeatedly performed, at a certain point, there may be a region on each electrode plate that can be used as an electrode and a region that cannot be used as a result of the deterioration. When electrolysis is performed with each electrode plate including a region that cannot be used as an electrode, there is a risk that the electrolysis efficiency is likely to decrease.

[0108] In contrast, in the spatial purification device 1 according to the present embodiment, the plane P3 and the plane P4 are arranged to face each other with the second anion exchange membrane 30b interposed therebetween. This arrangement allows a uniform electric field to be generated between the electrolytic cell side anode 11 and the second supply cell side cathode 21, and the current between the two electrodes is also uniformly distributed. Therefore, deterioration of the catalyst layer on the surface of each electrode plate occurs uniformly, so that even when electrolysis is performed repeatedly, uneven deterioration of the catalyst layer on the surface of each electrode plate caused by an uneven electric field can be suppressed. Therefore, a decrease in electrolysis efficiency can be suppressed.

[0109] An outline of one aspect of the present disclosure is as follows.

[0110] (Item 1) an electrolytic cell (10) for storing a first aqueous solution (L1) containing chloride ions; a first supply tank (20a) for storing a second aqueous solution (L2) containing hydroxide ions and supplying the hydroxide ions to the first aqueous solution (L1); a second supply tank (20b) for storing a third aqueous solution (L3) 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) provided in the electrolytic cell (10); a first supply tank-side cathode (12) provided in the first supply tank (20a); a second supply tank-side cathode (21) provided in the second supply tank (20b); a first anion exchange membrane (30a) connecting the electrolytic cell (10) and the first supply cell (20a) so as to be permeable to anions based on a voltage applied between the electrolytic cell-side anode (11) and the first supply cell-side cathode (12); a second anion exchange membrane (30b) connecting the electrolytic cell (10) and the second supply cell (20b) so as to be permeable to anions based on a voltage applied between the electrolytic cell-side anode (11) and the second supply cell-side cathode (21); a first membrane-type electrolysis unit (E1) provided between the electrolytic cell (10) and the first supply cell (20a), for generating hypochlorous acid in the electrolytic cell (10) by first membrane-type electrolysis of the first aqueous solution (L1) and the second aqueous solution (L2) through the first anion exchange membrane (30a) by passing a first current between the electrolytic cell-side anode (11) and the first supply cell-side cathode (12); a second membrane-containing electrolysis section (E2) provided between the electrolytic cell (10) and the second supply cell (20b), for performing second membrane-containing electrolysis via the second anion exchange membrane (30b) by passing a second current between the electrolytic cell-side anode (11) and the second supply cell-side cathode (21); a current control unit (40) that controls the second current so as to replenish chloride ions contained in the first aqueous solution (L1) that have been reduced by the first diaphragm electrolysis, thereby causing chloride ions contained in the third aqueous solution (L3) to permeate through the second anion exchange membrane (30b) and supply them to the first aqueous solution (L1); A space purification device (1).

[0111] According to this configuration, the chloride ions consumed by the first aqueous solution (L1) can be appropriately supplied from the third aqueous solution (L3), so that the space purification device (1) can stably generate a desired amount of hypochlorous acid gas. Therefore, the desired amount of hypochlorous acid gas can be stably generated for a long period of time, such as one year, without supplying an aqueous solution containing chloride ions from the outside.

[0112] (Item 2) The current control unit (40) applies the first current and the second current at a predetermined ratio, thereby maintaining the chloride ion concentration of the first aqueous solution (L1) at a predetermined concentration. The space purification device (1) according to item 1.

[0113] According to this configuration, the chloride ion concentration in the first aqueous solution (L1) is maintained at a predetermined concentration, so that a desired amount of hypochlorous acid gas can be stably generated.

[0114] (Item 3) The current control unit (40) a voltage acquiring unit (41) that acquires a voltage between the electrolytic cell side anode (11) and the first supply cell side cathode (12); a calculation unit (42) that calculates the conductivity of the first aqueous solution (L1) based on the voltage acquired by the voltage acquisition unit (41); an estimation unit (43) that estimates a concentration of the first aqueous solution (L1) based on the electrical conductivity calculated by the calculation unit (42), The current control unit (40) The first current and the second current are caused to flow simultaneously; when the chloride ion concentration of the first aqueous solution (L1) is lower than a predetermined concentration, a current ratio between the first current and the second current is changed so that an amount of chloride ions permeating from the third aqueous solution (L3) through the second anion exchange membrane (30b) and supplied to the first aqueous solution (L1) is increased; when the chloride ion concentration of the first aqueous solution (L1) is higher than the predetermined concentration, a current ratio between the first current and the second current is changed so as to reduce an amount of chloride ions that permeate from the third aqueous solution (L3) through the second anion exchange membrane (30b) and are supplied to the first aqueous solution (L1). The space purification device (1) according to item 1.

[0115] According to this configuration, when the first current and the second current are passed simultaneously, the current ratio between the first current and the second current is controlled, so that the chloride ion concentration in the first aqueous solution (L1) is maintained at a predetermined concentration, and a desired amount of hypochlorous acid gas can be stably generated.

[0116] (Item 4) When the chloride ion concentration of the first aqueous solution (L1) is the predetermined concentration, the current ratio of the first current and the second current is not changed. The space purification device (1) according to item 3.

[0117] According to this configuration, the current ratio between the first current and the second current is not changed, so that a desired amount of hypochlorous acid gas can be stably generated by simple control.

[0118] (Item 5) a voltage acquiring unit (41) that acquires a voltage between the electrolytic cell side anode (11) and the first supply cell side cathode (12); a calculation unit (42) that calculates the conductivity of the first aqueous solution (L1) based on the voltage acquired by the voltage acquisition unit (41); an estimation unit (43) that estimates a concentration of the first aqueous solution (L1) based on the electrical conductivity calculated by the calculation unit (42), The current control unit (40) The first current is caused to flow at a predetermined value while the second current is controlled; The control of the second current includes: When the chloride ion concentration of the first aqueous solution (L1) is lower than a predetermined concentration, the second current is applied so as to increase the amount of chloride ions that permeate from the third aqueous solution (L3) through the second anion exchange membrane (30b) and are supplied to the first aqueous solution (L1); When the chloride ion concentration of the first aqueous solution (L1) is higher than the predetermined concentration, the second current is stopped so that the supply of chloride ions from the third aqueous solution (L3) to the first aqueous solution (L1) is stopped. The space purification device (1) according to item 1.

[0119] According to this configuration, when a first current is passed at a predetermined value and a second current is passed at the same time, only the second current is controlled, so that the chloride ion concentration of the first aqueous solution (L1) is maintained at a predetermined concentration through simple control, and a desired amount of hypochlorous acid gas can be stably generated.

[0120] (Item 6) a voltage acquiring unit (41) that acquires a voltage between the electrolytic cell side anode (11) and the first supply cell side cathode (12); a calculation unit (42) that calculates the conductivity of the first aqueous solution (L1) based on the voltage acquired by the voltage acquisition unit (41); an estimation unit (42) that estimates a concentration of the first aqueous solution (L1) based on the electrical conductivity calculated by the calculation unit (42), The current control unit (40) when the chloride ion concentration of the first aqueous solution (L1) is lower than a predetermined concentration, the first current is stopped and the second current is simultaneously applied so as to increase the amount of chloride ions permeating from the third aqueous solution (L3) through the second anion exchange membrane (30b) and being supplied to the first aqueous solution (L1); When the chloride ion concentration of the first aqueous solution (L1) is higher than a predetermined concentration, stopping the second current and simultaneously supplying the first current so as to stop the supply of chloride ions from the third aqueous solution (L3) to the first aqueous solution (L1); The space purification device (1) according to item 1.

[0121] According to this configuration, the first current is stopped and the second current is allowed to flow at the same time, or the second current is stopped and the first current is allowed to flow at the same time, so that the chloride ion concentration in the first aqueous solution (L1) is maintained at a predetermined concentration, and a desired amount of hypochlorous acid gas can be stably generated.

[0122] (Item 7) When the first aqueous solution (L1) is an aqueous sodium chloride solution or an aqueous potassium chloride solution, and the third aqueous solution (L3) is an aqueous hydrochloric acid solution, the third aqueous solution (L3) contains sodium chloride or potassium chloride to have the same molar concentration as the sodium ion or potassium ion contained in the first aqueous solution (L1). The space purification device (1) according to item 1.

[0123] This configuration makes it possible to prevent the metal cations (sodium ions or potassium ions) contained in the first aqueous solution (L1) from permeating through the second anion exchange membrane (30b) into the third aqueous solution (L3). This makes it possible to prevent changes in pH caused by the permeation of the metal cations. In other words, it is possible to prevent unintended changes in pH of the first aqueous solution (L1).

[0124] (Item 8) a housing for housing the electrolytic tank (10), the first supply tank (20a), and the second supply tank (20b); an inlet (15) disposed in the housing above a liquid level (S1) of the first aqueous solution (L1) stored in the electrolytic cell (10), and through which air flows in from an external space of the housing; a mixing space (16) for mixing the volatilized hypochlorous acid with the air flowing in from the inlet (15); an outlet (17) through which the mixed air flows out to the exterior space; The space purification device (1) according to item 1, comprising:

[0125] According to this configuration, air introduced into the inlet (15) from the space outside the space purification device (1) can be mixed with hypochlorous acid in the mixing space (16) and then released into the outside space from the outlet (17). This makes it possible to remove bacteria, fungi, viruses, odors, and the like contained in the air in the space outside the space purification device (1).

[0126] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and it can be easily imagined that various improvements and modifications are possible within the scope of the present invention without departing from the spirit of the present invention.

[0127] In the spatial purification device 1 according to the first embodiment, the electrodes (electrolytic cell side anode 11, first supply cell side cathode 12, second supply cell side cathode 21) are inserted from the side (xz plane side on the negative y-axis side) of each cell (electrolytic cell 10, first supply cell 20a, second supply cell 20b) toward the inside of each cell in the horizontal direction (y-axis direction), but this is not limited thereto. For example, each of the electrodes may be inserted from the upper side of the top surface of each cell (positive z-axis side in FIG. 1) toward the inside of each cell (negative z-axis direction). Alternatively, each of the electrodes may be inserted from the lower side (negative z-axis side) of the bottom surface of each cell toward the inside of each cell (positive z-axis direction).

[0128] In addition, in the spatial purification device 1 according to the first embodiment, the inflow port 15, which is an opening for allowing air from the space outside the housing to flow in, is provided on the top surface of the electrolytic cell 10 (xy plane on the z-axis positive side in FIG. 1), but is not limited thereto. For example, the inflow port 15 may be provided on the bottom surface of the electrolytic cell 10 (xy plane on the z-axis negative side in FIG. 1), and air may be introduced by an air pump. This allows air to be supplied as air bubbles from the inflow port 15 into the first aqueous solution L1, so that the air discharged from the outlet 17 can contain a larger amount of hypochlorous acid gas. [Industrial Applicability]

[0129] The air purifying device of this embodiment 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, and is therefore useful as a device for purifying or sterilizing indoor spaces, etc. [Explanation of symbols]

[0130] 1. Space Purification Device 10 Electrolytic cell 11 Electrolyzer side anode 11a Electrolytic tank side anode plate immersion part 11b Electrolytic tank side anode plate protrusion 12 First supply tank side cathode 12a First supply tank side cathode plate immersion section 12b Cathode plate protrusion on the first supply tank side 13 Wiring 14 Wiring 15 Inlet 16 Mixed space 17 Outlet 20a 1st supply tank 20b 2nd supply tank 21 2nd supply tank side cathode 21a 2nd supply tank side cathode plate immersion part 21b 2nd supply tank side cathode plate protrusion 22 Wiring 23a 1st outlet 23b 2nd outlet 30a First anion exchange membrane 30b Second anion exchange membrane 40 Current control section 41 Voltage acquisition unit 42 Calculation section 43 Estimation part E1 1st diaphragm electrolytic section E2 Second diaphragm electrolytic section L1 1st aqueous solution L2 2nd aqueous solution L3 3rd aqueous solution S1 liquid level S2 liquid level S3 liquid level

Claims

1. an electrolytic cell for storing a first aqueous solution containing chloride ions; a first supply tank for storing a second aqueous solution containing hydroxide ions and supplying hydroxide ions to the first aqueous solution; a second supply tank for storing a third aqueous solution containing chloride ions at a higher concentration than that of the first aqueous solution and supplying chloride ions to the first aqueous solution; an electrolytic cell-side anode provided in the electrolytic cell; a first supply tank side cathode provided in the first supply tank; a second supply tank side cathode provided in the second supply tank; a first anion exchange membrane connecting the electrolytic cell and the first supply cell in a manner allowing anions to pass therethrough based on a voltage applied between the electrolytic cell side anode and the first supply cell side cathode; a second anion exchange membrane connecting the electrolytic cell and the second supply cell in a manner allowing anions to pass therethrough based on a voltage applied between the electrolytic cell side anode and the second supply cell side cathode; a first membrane-containing electrolysis section provided between the electrolytic cell and the first supply cell, which generates hypochlorous acid in the electrolytic cell by first membrane-containing electrolysis of the first aqueous solution and the second aqueous solution via the first anion exchange membrane by passing a first current between the electrolytic cell-side anode and the first supply cell-side cathode; a second membrane-containing electrolysis section provided between the electrolytic cell and the second supply cell, which performs second membrane-containing electrolysis via the second anion exchange membrane by passing a second current between the electrolytic cell-side anode and the second supply cell-side cathode; 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 first diaphragm electrolysis, thereby causing chloride ions contained in the third aqueous solution to permeate through the second anion exchange membrane and be supplied to the first aqueous solution; A space purification device comprising:

2. the current control unit applies the first current and the second current at a predetermined ratio, thereby maintaining a chloride ion concentration of the first aqueous solution at a predetermined concentration. The space purification device according to claim 1 .

3. The current control unit is a voltage acquiring unit that acquires a voltage between the electrolytic cell side anode and the first supply cell side cathode; a calculation unit that calculates the conductivity of the first aqueous solution based on the voltage acquired by the voltage acquisition unit; an estimation unit that estimates a concentration of the first aqueous solution based on the electrical conductivity calculated by the calculation unit, The current control unit is The first current and the second current are caused to flow simultaneously; When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, a current ratio of the first current and the second current is changed so that an amount of chloride ions permeating from the third aqueous solution through the second anion exchange membrane and supplied to the first aqueous solution is increased; When the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, a current ratio of the first current and the second current is changed so that an amount of chloride ions permeating from the third aqueous solution through the second anion exchange membrane and supplied to the first aqueous solution is reduced. The space purification device according to claim 1 .

4. When the chloride ion concentration of the first aqueous solution is the predetermined concentration, the current ratio of the first current and the second current is not changed. The space purification device according to claim 3.

5. a voltage acquiring unit that acquires a voltage between the electrolytic cell side anode and the first supply cell side cathode; a calculation unit that calculates the conductivity of the first aqueous solution based on the voltage acquired by the voltage acquisition unit; an estimation unit that estimates a concentration of the first aqueous solution based on the electrical conductivity calculated by the calculation unit, The current control unit is The first current is caused to flow at a predetermined value while the second current is controlled; The control of the second current includes: When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, the second current is applied so as to increase the amount of chloride ions permeating from the third aqueous solution through the second anion exchange membrane and being supplied to the first aqueous solution; When the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, the second current is stopped so that the supply of chloride ions from the third aqueous solution to the first aqueous solution is stopped. The space purification device according to claim 1 .

6. a voltage acquiring unit that acquires a voltage between the electrolytic cell side anode and the first supply cell side cathode; a calculation unit that calculates the conductivity of the first aqueous solution based on the voltage acquired by the voltage acquisition unit; an estimation unit that estimates a concentration of the first aqueous solution based on the electrical conductivity calculated by the calculation unit, The current control unit is When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, the first current is stopped and the second current is simultaneously supplied so that an amount of chloride ions permeating from the third aqueous solution through the second anion exchange membrane and supplied to the first aqueous solution is increased; When the chloride ion concentration of the first aqueous solution is higher than a predetermined concentration, stopping the second current and simultaneously supplying the first current so as to stop the supply of chloride ions from the third aqueous solution to the first aqueous solution; The space purification device according to claim 1 .

7. When the first aqueous solution is a sodium chloride aqueous solution or a potassium chloride aqueous solution, and the third aqueous solution is a hydrochloric acid aqueous solution, the third aqueous solution contains sodium chloride or potassium chloride to have the same molar concentration as that of sodium ions or potassium ions contained in the first aqueous solution. The space purification device according to claim 1 .

8. a housing for housing the electrolytic bath, the first supply bath, and the second supply bath; an inlet that is disposed in the housing above a liquid level of the first aqueous solution stored in the electrolytic cell, and through which air flows in from an external space of the housing; A mixing space for mixing the volatilized hypochlorous acid with the air flowing in from the inlet; an outlet through which the mixed air flows out to the exterior space; The space purification device of claim 1 .

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