Space purification device

Abstract

Provided is a space purification device (1) comprising an electrolytic bath (10) for retaining a first aqueous solution (L1), a supply tank (20) for retaining a second aqueous solution (L2) and supplying chloride ions to the first aqueous solution (L1), and a negative ion exchange membrane (30) that connects the electrolytic bath (10) and the supply tank (20) in a manner enabling permeation by negative ions. The second aqueous solution (L2) is a metal chloride aqueous solution. Membrane electrolysis is performed, whereby the chloride ions contained in the second aqueous solution (L2) retained in the supply tank (20) are allowed to permeate through the negative ion exchange membrane (30) and are supplied to the first aqueous solution (L1) retained in the electrolytic bath (10) so as to supplement chloride ions contained in the first aqueous solution (L1), which is reduced by membraneless electrolysis. The metal ions contained in the second aqueous solution (L2) and hydroxide ions generated by the membrane electrolysis are reacted within the supply tank (20) to form a precipitate of a metal hydroxide.

Description

Space Purification Device

[0001] The present disclosure relates to a space purification device.

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

[0003] Japanese Patent Application Laid-Open No. 2019-174032

[0004] However, when an air purification device generates hypochlorous acid water by electrolyzing a sodium chloride solution, sodium hydroxide, a strong alkaline substance, may be generated. When such an air purification device is miniaturized and installed at a designated installation location by a contractor, it is expected that the air purification device may be overturned or dropped when the contractor removes the air purification device after use or during transportation after removal. In this case, there is a possibility that the generated sodium hydroxide, a strong alkaline substance, may leak outside the air purification device.

[0005] The present disclosure provides a space purification device that suppresses strong alkalinity after electrolysis of an aqueous solution stored in a supply tank, thereby improving safety.

[0006] The spatial purification device according to the present disclosure includes an electrolytic cell for storing a first aqueous solution containing chloride ions; a supply cell for storing a second aqueous solution containing a higher concentration of chloride ions than the first aqueous solution and for supplying chloride ions to the first aqueous solution; a housing for storing the electrolytic cell and the supply cell; an inlet disposed within the housing above the liquid level of the first aqueous solution stored in the electrolytic cell and through which air flows in from the space outside the housing; an electrolytic cell-side anode and an electrolytic cell-side cathode disposed in the electrolytic cell; a supply cell-side cathode disposed in the supply cell; an anion exchange membrane disposed to connect the electrolytic cell and the supply cell and allowing anions to pass therethrough based on a voltage applied between the electrolytic cell-side anode and the supply cell-side cathode; and a membrane-less electrolysis unit disposed in the electrolytic cell for generating hypochlorous acid by passing a first current between the electrolytic cell-side anode and the electrolytic cell-side cathode. The electrolysis system comprises a diaphragm-equipped electrolysis section that is provided between the electrolytic cell and the supply cell and performs membrane-equipped electrolysis via an anion exchange membrane by passing a second current between the electrolytic cell-side anode and the supply cell-side cathode, a mixing space that mixes volatilized hypochlorous acid with air that has flowed in from the inlet, and an outlet through which the mixed air flows out to an external space, wherein the second aqueous solution is a metal chloride aqueous solution containing metal ions and chloride ions, and by performing membrane-equipped electrolysis, chloride ions contained in the second aqueous solution stored in the supply cell are supplied to the first aqueous solution stored in the electrolytic cell through the anion exchange membrane so as to replenish chloride ions contained in the first aqueous solution that have been reduced by membrane-less electrolysis, and within the supply cell, metal ions contained in the second aqueous solution react with hydroxide ions produced by the membrane-equipped electrolysis to form a precipitate of metal hydroxide.

[0007] The present disclosure makes it possible to provide a space purification device that suppresses strong alkalinity after electrolysis of an aqueous solution and has improved safety.

[0008] FIG. 1 is a perspective view showing a space purification device according to a first embodiment. FIG. 2 is a partial front cross-sectional view showing the space purification device of FIG. 1. FIG. 3 is a list of reaction formulas occurring in the diaphragm-less electrolysis section. FIG. 4 is a reaction formula including the ratio of the current flowing in the diaphragm-less electrolysis section to the current flowing in the diaphragm-containing electrolysis section. FIG. 5 is a list of reaction formulas occurring in the diaphragm-containing electrolysis section. FIG. 6 is a block diagram showing a current control section according to the first embodiment. FIG. 7 is a perspective view showing a space purification device according to a second embodiment. FIG. 8 is a partial front cross-sectional view showing the space purification device of FIG. 7. FIG. 9 is a list of reaction formulas occurring in the diaphragm-less electrolysis section. FIG. 10 is a reaction formula showing the ratio of the current flowing in the diaphragm-less electrolysis section to the current flowing in the diaphragm-containing electrolysis section. FIG. 11 is a list of reaction formulas occurring in the diaphragm-containing electrolysis section. FIG. 12 is a block diagram showing a current control section according to the second embodiment.

[0009] Hereinafter, a specific embodiment 1 of the present disclosure 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 relationships of the components. Unless otherwise specified, the positive direction of the z axis is vertically upward. The xy plane is a horizontal plane, and is common to all drawings.

[0011] 1 is a perspective view showing an outline of a space purification device 1 according to embodiment 1. The space purification device 1 performs electrolysis on a first aqueous solution L1 containing chloride ions in an electrolytic bath 10 (described later) to generate and volatilize hypochlorous acid. The space 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 discharging the volatilized hypochlorous acid into the external space of a housing B constituting 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, installation locations for the space purification device 1 include, for example, inside an air conditioner, the periphery of an electric fan, the periphery of a circulator, the periphery of a ceiling fan, the inside of a humidifier, and the inside of an air purifier.

[0013] The spatial purification device 1 includes a housing B, an electrolytic cell 10 , a supply cell 20 , an anion exchange membrane 30 , and a current control unit 40 .

[0014] The housing B houses the electrolytic cell 10, the supply cell 20, the anion exchange membrane 30, and the current control unit 40. That is, the space purification device 1 may be an integrated unit formed by the housing B. The shape of the housing B can be changed appropriately depending on the location where the space purification device 1 is installed, and may be, for example, a rectangular parallelepiped or cylindrical shape. The space purification device 1 has a small size that can be stored inside an air conditioner, for example, approximately 10 cm x 7 cm x 4 cm.

[0015] The electrolytic bath 10 is a bath for storing a first aqueous solution L1 containing chloride ions. The electrolytic bath 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 bath 10. The first aqueous solution L1 is, for example, an aqueous solution in which an electrically conductive electrolyte is dissolved, and specifically, a dilute chloride aqueous solution having a predetermined chloride ion concentration. More specifically, the first aqueous solution L1 is, for example, a sodium chloride aqueous solution or a dilute potassium chloride aqueous solution.

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

[0017] The supply tank 20 is a tank for storing the second aqueous solution L2 containing chloride ions. The chloride ions contained in the second aqueous solution L2 in the supply tank 20 permeate through the anion exchange membrane 30 and are supplied to the first aqueous solution L1 in the electrolytic tank 10.

[0018] The supply tank 20 is a tank for storing a second aqueous solution L2 containing chloride ions and supplying the chloride ions to the first aqueous solution L1. FIG. 1 illustrates the second aqueous solution L2 stored in the supply tank 20. The chloride ion concentration of the second aqueous solution L2 is higher than that of the first aqueous solution L1. To ensure safety in the event of a leak, the solute of the second aqueous solution L2 is preferably a substance classified under the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) with the same level of safety as sodium chloride. Specifically, the second aqueous solution L2 is a metal chloride aqueous solution containing metal ions and chloride ions. The second aqueous solution L2 is subjected to membrane electrolysis, as described below, whereby the chloride ions contained in the second aqueous solution L2 react with the hydroxide ions generated by the membrane electrolysis to form a metal hydroxide precipitate. Preferably, the second aqueous solution L2 is a high-concentration magnesium chloride aqueous solution or a saturated magnesium chloride aqueous solution. When an aqueous magnesium chloride solution is used as the second aqueous solution L2, the mass percent concentration of the aqueous magnesium chloride solution is, for example, 10% to 35%.

[0019] Assuming continuous use for eight hours every day for one year, the respective volumes of the electrolytic cell 10 and the supply cell 20 are preferably set so that the volume of the supply cell 20 is at least about 12 times the volume of the electrolytic cell 10. By setting such a volume ratio, the supply cell 20 can store the second aqueous solution L2 containing a sufficient amount of chloride ions necessary to supply to the first aqueous solution L1 in the electrolytic cell 10. Therefore, chloride ions can be stably supplied from the second aqueous solution L2 stored in the supply cell 20 to the first aqueous solution L1 stored in the electrolytic cell 10. The amount of the first aqueous solution L1 stored in the electrolytic cell 10 is, for example, about 2 to 10 mL.

[0020] The anion exchange membrane 30 is provided to connect the electrolytic cell 10 and the supply cell 20, and is a membranous member that allows anions to pass therethrough based on a voltage applied between the electrolytic cell 10 and the supply cell 20. More specifically, when a voltage is applied between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21 (described below), membrane-type electrolysis occurs via the anion exchange membrane 30. By the membrane-type electrolysis using the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21, chloride ions contained in the second aqueous solution L2 permeate the anion exchange membrane 30 and are supplied to the first aqueous solution L1 (in the negative direction of the x-axis, indicated by a thick black arrow).

[0021] The anion exchange membrane 30 in the first embodiment is not a type of anion exchange membrane through which anions permeate due to osmotic pressure without using electricity. Furthermore, the anion exchange membrane 30 does not allow sodium ions, which are cations, to permeate. More specifically, when chloride ions contained in the second aqueous solution L2 permeate the anion exchange membrane 30 and are supplied to the first aqueous solution L1 by membrane electrolysis using the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21, sodium ions, which are cations, do not permeate the anion exchange membrane 30. The anion exchange membrane 30 is, for example, a hydrocarbon-based anion exchange membrane. Specific examples of hydrocarbon-based anion exchange membranes include membranes that have monovalent anion-selective permeability, alkali resistance, or high-temperature resistance.

[0022] The anion exchange membrane 30 is disposed between the electrolytic cell 10 and the supply cell 20. For example, the surface of the electrolytic cell 10 facing the supply cell 20 (the yz plane on the positive side of the x-axis) and the surface of the supply cell 20 facing the electrolytic cell 10 (the yz plane on the negative side of the x-axis) may each be formed by a frame-shaped member. When the opposing surfaces of the electrolytic cell 10 and the supply cell 20 are each formed by a frame-shaped member, the anion exchange membrane 30 may be disposed so as to be fitted into the frame-shaped member.

[0023] The current control unit 40 controls the current used in the diaphragmless electrolysis and the diaphragm-containing electrolysis. More specifically, the current control unit 40 controls the current used in the diaphragmless electrolysis, which is performed using a pair of electrolytic cell-side anodes 11 and electrolytic cell-side cathodes 12 arranged in the electrolytic cell 10. The current control unit 40 also controls the current used in the diaphragm-containing electrolysis, which is performed via an anion exchange membrane 30 using a pair of electrolytic cell-side anodes 11 and feed cell-side cathodes 21, across the electrolytic cell 10 and the feed cell 20. The electrolytic cell-side anode 11 is used for both the diaphragm-less electrolysis and the diaphragm-containing electrolysis. That is, the space purification device 1 according to the first embodiment includes one anode and two cathodes, for a total of three electrodes. Because the feed cell 20 includes only cathodes, chlorine is not generated within the feed cell 20 by a chemical reaction, which will be described later.

[0024] Hereinafter, the details of each component will be described in more detail with reference to FIGS.

[0025] As shown in FIG. 1 , the electrolytic cell 10 includes an electrolytic cell-side anode 11 , an electrolytic cell-side cathode 12 , a wire 13 , a wire 14 , an inlet 15 , a mixing space 16 , and an outlet 17 .

[0026] The electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 are a pair of electrodes used in the electrolysis of the first aqueous solution L1. As shown in Fig. 1 , no diaphragm such as an ion exchange membrane is provided between the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12. That is, the electrolysis of the first aqueous solution L1 performed using the pair of the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 is diaphragm-less electrolysis. Hypochlorous acid, which is used for space purification, is produced by the diaphragm-less electrolysis of the first aqueous solution L1 performed using the pair of the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12.

[0027] The electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12 each have a plate-like shape. That is, the electrolytic cell-side anode 11 is an electrolytic cell-side anode plate 11 having a plate-like shape, and the electrolytic cell-side cathode 12 is an electrolytic cell-side cathode plate 12 having a plate-like shape. Plate-like shapes include rectangular and oblong shapes. Hereinafter, the electrolytic cell-side anode 11 will also be referred to as the electrolytic cell-side anode plate 11. The electrolytic cell-side cathode 12 will also be referred to as the electrolytic cell-side cathode plate 12.

[0028] As an example, a case will be described in which the plate shapes of the electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12 are rectangular. The electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12 are arranged such that the shorter side of the rectangle is aligned with the vertical direction (z-axis direction). This arrangement can prevent bubbles generated by chemical reactions from adhering to both sides of the rectangle of each electrode. Furthermore, compared to when the longer side of the rectangle is aligned with the vertical direction (z-axis direction), when the shorter side is aligned with the vertical direction (z-axis direction), bubbles generated at the lower part (negative side of the z-axis) of the electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12 are prevented from adhering to the upper part (positive side of the z-axis) of the electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12.

[0029] The electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12 are arranged such that the longitudinal direction of the rectangle is along the horizontal direction (y-axis direction). In other words, the electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12 are arranged such that the planes (yz planes) of their respective rectangles face each other with a predetermined gap between them. The predetermined gap is a gap appropriate for electrolysis performed using a pair of electrolytic cell-side anode plate 11 and electrolytic cell-side cathode plate 12.

[0030] The electrolytic cell-side anode plate 11 has an electrolytic cell-side anode plate immersed portion 11a and an electrolytic cell-side anode plate protruding portion 11b. Similarly, the electrolytic cell-side cathode plate 12 has an electrolytic cell-side cathode plate immersed portion 12a and an electrolytic cell-side cathode plate protruding portion 12b.

[0031] The electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12 are inserted from the outside of the electrolytic cell 10 toward the inside. In FIG. 1 , as an example, the electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12 are inserted horizontally (in the y-axis direction) from the side of the electrolytic cell 10 (the xz plane side on the negative side of the y-axis). The electrolytic cell-side anode plate immersed portion 11a and the electrolytic cell-side cathode plate immersed portion 12a inserted into the electrolytic cell 10 are positioned inside the electrolytic cell 10 and are entirely immersed in the first aqueous solution L1. In other words, the first aqueous solution L1 is stored in the electrolytic cell 10 so that the electrolytic cell-side anode plate immersed portion 11a and the electrolytic cell-side cathode plate immersed portion 12a are entirely immersed. That is, the first aqueous solution L1 is stored in the electrolytic cell 10 so that the liquid level S1 of the first aqueous solution L1 exceeds the upper end (the end on the positive side of the z-axis) of the electrolytic cell side anode plate immersed portion 11a and the electrolytic cell side cathode plate immersed portion 12a.

[0032] The electrolytic cell-side anode plate protrusion 11b and the electrolytic cell-side cathode plate protrusion 12b are disposed on the exterior side of the electrolytic cell 10. Wiring 13 and wiring 14 are lines through which current flows. The electrolytic cell-side anode plate protrusion 11b is electrically connected to a current control unit 40 via wiring 13, and the electrolytic cell-side cathode plate protrusion 12b is electrically connected to a current control unit 40 via wiring 14.

[0033] The electrolytic cell side anode plate 11 and the electrolytic cell side cathode plate 12 may be, for example, a platinum iridium titanium electrode, a platinum electrode, a ruthenium titanium electrode, or an iridium titanium oxide electrode.

[0034] The inlet 15 is an opening through which air from the space outside the casing B flows in. That is, the inlet 15 is an opening through which air from the space outside the space purification device 1 flows in. In FIG. 1 , the inlet 15 is provided on the top surface of the electrolytic cell 10 (the x-y plane on the positive side of the z-axis) as an example, but it may be 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. 1 or rectangular tubular. When the top surface of the electrolytic cell 10 (the surface on the positive side of the z-axis) is close to the ceiling surface of the casing B, the inlet 15 may be a hole-like opening provided in a part of the top surface of the electrolytic cell 10. Alternatively, the inlet 15 and the top surface of the casing B (the surface on the positive side of the z-axis) may be integrally formed.

[0035] The mixing space 16 is a space formed above the electrolytic cell 10 (positive side of the z-axis) when 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 membrane-less electrolysis of the first aqueous solution L1 using a pair of electrolytic cell-side anode plates 11 and electrolytic cell-side cathode plates 12 with air from the external space that flows in through the inlet 15. The hypochlorous acid generated by membrane-less electrolysis includes volatilized and gasified hypochlorous acid gas and hypochlorous acid dissolved in the first aqueous solution L1. The hypochlorous acid gas is contained in the air that flows in through the inlet 15 and flows out to the external space through the outlet 17, which will be described later. The hypochlorous acid dissolved in the first aqueous solution L1 flows out to the external space through the outlet 17, which will be described later, by gas-liquid contact with the air that flows in through the inlet 15.

[0036] The outlet 17 is an opening through which mixed air, which is a mixture of air flowing in from the inlet 15 and hypochlorous acid generated by the membraneless electrolysis of the first aqueous solution L1, flows out to the space outside the casing B. That is, the outlet 17 is an opening through which the mixed air flows out to the space outside the space purification device 1. In FIG. 1 , the outlet 17 is provided on the top surface of the electrolytic cell 10 (the x-y plane on the positive side of the z-axis) as an example, similar to the inlet 15, but it need only 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. 1 or rectangular tubular. When the top surface (the surface on the positive side of the z-axis) of the electrolytic cell 10 is close to the ceiling surface of the casing B, the outlet 17 may be a hole-like opening provided in a part of the top surface of the electrolytic cell 10. Alternatively, the outlet 17 and the top surface (the surface on the positive side of the z-axis) of the casing B may be integrally formed.

[0037] The inlet 15 and the outlet 17 may be provided with a lid (not shown) that can be opened or closed or that can be removed. The lid may be configured to be closed when the space purification device 1 is transported, moved, or installed, and to be opened or removed when the space purification device 1 is used. Although the inlet 15 and the outlet 17 are described as having separate structures, the inlet 15 and the outlet 17 may each serve as both an inlet and an outlet depending on the direction of wind flowing into the space purification device 1.

[0038] The air containing hypochlorous acid that flows out from the outlet 17 into the space outside the space purification device 1 purifies the 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 B.

[0039] The supply tank 20 includes a supply tank-side cathode 21, wiring 22, and an outlet 23. The supply tank-side cathode 21 is an electrode paired with the electrolytic cell-side anode 11 and used for electrolysis of the second aqueous solution L2. As shown in FIG. 1 , an anion exchange membrane 30 is disposed between the electrolytic cell-side anode 11 and the supply tank-side cathode 21. That is, the electrolysis of the second aqueous solution L2 performed using the pair of the electrolytic cell-side anode 11 and the supply tank-side cathode 21 is membrane-less electrolysis. That is, the electrolytic cell-side anode 11 is used for both membrane-less electrolysis and membrane-with electrolysis. Chloride ions are supplied from the second aqueous solution L2 to the first aqueous solution L1 by the membrane-with electrolysis of the second aqueous solution L2 performed using the pair of the electrolytic cell-side anode 11 and the supply tank-side cathode 21.

[0040] The supply tank side cathode 21 is a supply tank side cathode plate 21 having a plate shape. The plate shape includes a rectangular shape and an oblong shape. Hereinafter, the supply tank side cathode 21 will also be referred to as a supply tank side cathode plate 21.

[0041] As an example, a case will be described in which the supply tank side cathode plate 21 also has a rectangular plate shape, similar to the electrolytic tank side anode plate 11. As shown in Fig. 1 , the supply tank side cathode plate 21 is arranged such that the shorter side of the rectangle is aligned along the vertical direction (z-axis direction). Furthermore, the supply tank side cathode plate 21 is arranged such that the longer side of the rectangle is aligned along the horizontal direction (y-axis direction).

[0042] The electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21 are each in close proximity to the anion exchange membrane 30. In this specification, "close proximity" includes both a state in which the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21 are close to the anion exchange membrane 30 with a predetermined gap therebetween, and a state in which the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21 are each in contact with the anion exchange membrane 30.

[0043] The plane of the rectangular plate on the anion exchange membrane 30 side of the electrolytic cell-side anode plate 11 (the yz plane on the positive x-axis side) is designated as plane P1. The plane of the rectangular plate on the anion exchange membrane 30 side of the supply cell-side cathode plate 21 (the yz plane on the negative x-axis side) is designated as plane P2. Planes P1 and P2 are arranged opposite each other with the anion exchange membrane 30 interposed therebetween. This arrangement allows a uniform electric field to be generated between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21.

[0044] The electrolytic cell-side anode plate 11 is disposed between the electrolytic cell-side cathode plate 12 and the anion exchange membrane 30. This arrangement makes it possible to maintain small potential differences between the electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12, and between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21.

[0045] The supply tank side cathode plate 21 includes a supply tank side cathode plate immersed portion 21a and a supply tank side cathode plate protruding portion 21b. The supply tank side cathode plate 21 is inserted from the outside of the electrolytic cell 10 toward the inside. In FIG. 1 , as an example, the supply tank side cathode plate 21 is inserted horizontally (in the y-axis direction) from the side of the electrolytic cell 10 (the xz plane side on the negative side of the y-axis). The supply tank side cathode plate immersed portion 21a inserted into the supply tank 20 is positioned inside the supply tank 20 and is entirely immersed in the second aqueous solution L2. In other words, the second aqueous solution L2 is stored in the supply tank 20 so that the entire supply tank side cathode plate immersed portion 21a is immersed. That is, the second aqueous solution L2 is stored in the supply tank 20 so that the liquid level S2 of the second aqueous solution L2 exceeds the upper end (the end on the positive side of the z-axis) of the supply tank side cathode plate immersed portion 21a.

[0046] 1, the supply tank-side cathode plate protrusion 21b is disposed on the exterior side of the supply tank 20. The wiring 22 is a line through which current flows. The supply tank-side cathode plate protrusion 21b is electrically connected to the current control unit 40 via the wiring 22.

[0047] As the supply tank side cathode plate 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.

[0048] The outlet 23 is an opening for discharging the hydrogen gas generated by the diaphragm electrolysis of the second aqueous solution L2 to the external space of the housing B. The outlet 23 may be, for example, a check valve. When a check valve is used as the outlet 23, the hydrogen gas inside the supply tank 20 is discharged to the external space, but the inflow of gases such as air from the external space can be suppressed. When the diaphragm electrolysis of the second aqueous solution L2 is repeated, the hydrogen gas accumulates inside the supply tank 20, and the internal pressure of the supply tank 20 increases. This increase in pressure opens the check valve, and the hydrogen gas is discharged to the external space of the supply tank 20.

[0049] Figure 2 is a partial front cross-sectional view showing the space purification device 1 of Figure 1. The housing B shown in Figure 1 is omitted from Figure 2. As shown in Figure 2, the space 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 above (on the positive z-axis side) the upper ends (on the positive z-axis side) of at least the electrolytic cell-side anode plate immersed portion 11a, the electrolytic cell-side cathode plate immersed portion 12a, and the supply cell-side cathode plate immersed portion 21a.

[0050] 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 water supply unit 19 supplies water to the electrolytic cell 10 so that the water level does not fall below the upper ends (portions on the positive side of the z-axis) of the electrolytic cell-side anode plate immersed portion 11a, the electrolytic cell-side cathode plate immersed portion 12a, and the supply cell-side cathode plate immersed portion 21a. The water supply unit 19 may be, for example, a Peltier element that can cool and condense moisture contained in the air into droplets, or a water tank that can store water. The water supply unit 19 may be located in any position that allows it to supply water to the electrolytic cell 10, and may be located on the top side of the electrolytic cell 10, or on the side or bottom side of the electrolytic cell 10.

[0051] When the space purification device 1 is equipped with the water level detection unit 18 and the water supply unit 19, the electrolytic cell-side anode plate immersed portion 11a and the electrolytic cell-side cathode plate immersed portion 12a can be maintained immersed in the first aqueous solution L1. This prevents the electrolytic cell-side anode plate immersed portion 11a and the electrolytic cell-side cathode plate immersed portion 12a from being exposed to air due to a decrease in the first aqueous solution L1, thereby maintaining the electrolysis efficiency of membraneless electrolysis.

[0052] 2, the space purification device 1 according to the first embodiment includes a diaphragm-less electrolysis unit E1 and a diaphragm-containing electrolysis unit E2. The current control unit 40 controls the first current flowing through the diaphragm-less electrolysis unit E1 and the second current flowing through the diaphragm-containing electrolysis unit E2, thereby controlling the chemical reactions occurring in the diaphragm-less electrolysis unit E1 and the diaphragm-containing electrolysis unit E2.

[0053] The diaphragm-less electrolysis unit E1 is provided in the electrolytic cell 10. The diaphragm-less electrolysis unit E1 produces hypochlorous acid by electrolyzing the first aqueous solution L1 without a diaphragm by passing a first current between the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12. In other words, the diaphragm-less electrolysis unit E1 includes the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12.

[0054] The membrane-equipped electrolysis unit E2 is provided across the electrolytic cell 10 and the supply cell 20. A second current is passed between the electrolytic cell-side anode 11 and the supply cell-side cathode 21, thereby performing membrane-equipped electrolysis via the anion exchange membrane 30. In other words, the membrane-equipped electrolysis unit E2 includes the electrolytic cell-side anode 11, the supply cell-side cathode 21, and the anion exchange membrane 30.

[0055] Here, we will explain in detail the chemical reaction that occurs in the diaphragm-less electrolysis section E1 provided in the electrolytic cell 10 and the chemical reaction that occurs in the diaphragm-containing electrolysis section E2 provided between the electrolytic cell 10 and the supply cell 20. Below, we will explain the case where the first aqueous solution L1 containing chloride ions is a sodium chloride aqueous solution and the second aqueous solution L2 is a magnesium chloride aqueous solution.

[0056] [Non-diaphragm electrolysis section E1 (electrolytic cell 10)] Fig. 3 is a list of reaction formulas occurring in the non-diaphragm electrolysis section E1. Sodium chloride (NaCl) contained in the sodium chloride aqueous solution is converted into sodium ions (Na ＋ ) and chloride ions (Cl－ When a predetermined voltage is applied to the membraneless electrolysis section E1, a current flows, electrons move, and the chemical reaction shown in FIG. 3 occurs. Reaction formula (a) in FIG. 3: Electrolytic cell side anode 11 (chlorine generation reaction) At the electrolytic cell side anode 11, chloride ions (Cl ) ionized in water are generated. － ) is an electron (e － ) and loses chlorine (Cl ２ 3: Electrolytic cell side cathode 12 (hydrogen generation reaction) At the electrolytic cell side cathode 12, water (H ２ O) is electron (e － ) and hydrogen (H ２ ) and hydroxide ions (OH － 3: Electrolytic cell-side anode 11 (oxygen generation reaction) At the electrolytic cell-side anode 11, water (H ２ O) to electrons (e － ) is taken away, and oxygen (O ２ ) and hydrogen ions (H ＋ 3 : Reaction in the first aqueous solution L1 (hypochlorous acid generation reaction) In the first aqueous solution L1 of the electrolytic cell 10, chlorine (Cl ) generated by reaction in the reaction in the reaction in the electrolytic cell 10 is generated. ２ ) is the water (H ２ O), hydrolysis occurs, generating hydrochloric acid (HCl) and hypochlorous acid (HClO). Hydrochloric acid (HCl) ionizes in an aqueous solution, generating hydrogen ions (H ＋ ) and chloride ions (Cl － 3(e): When a voltage is applied to the anion exchange membrane 30 and a current flows through the membrane electrolysis section E2, the first aqueous solution L1 stored in the electrolytic cell 10 generates electrons (e － ) is lost. － In the first aqueous solution L1, which has lost its chloride ions (Cl), a force that maintains electrical neutrality acts, and negatively charged chloride ions (Cl － ) is supplied from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10 through the anion exchange membrane 30. In the first aqueous solution L1, the electrons (e － ) changes to chloride ions (Cl －3 (f): Hypochlorous acid generating reaction (equilibrium reaction formula) Reaction formula (f) in FIG. 3 shows the equilibrium reaction formula of the hypochlorous acid generating reaction. － When the equilibrium state shifts to the right side depending on the increase or decrease of Cl ２ +H ２ O), or the left side (HCl + HClO) can occur. － The current is controlled as described below so that the apparent increase or decrease in the amount of chloride ions is prevented. Equation (g) of FIG. 3: Equation of chloride ion change during electrolysis The amount of chloride (Cl) generated by reaction equation (a) of FIG. ２ ) is converted into hydrochloric acid (HCl) and hypochlorous acid (HClO) according to reaction formula 3(d). This can be expressed in a single formula as formula (g) in Figure 3.

[0057] Figure 4 shows a reaction formula including the ratio of the current flowing in the diaphragm-less electrolysis section E1 to the current flowing in the diaphragm-containing electrolysis section E2. Here, the ratio of the current flowing in the electrolytic cell-side anode 11 used for the chlorine generation reaction of reaction formula (a) in Figure 3 is represented as "x," and the ratio of the current used for the oxygen generation reaction of reaction formula (c) in Figure 3 is represented as "1-x." Furthermore, the ratio of the current flowing in the electrolytic cell-side anode 11 originating from the diaphragm-less electrolysis section E1 is represented as "y," and the ratio of the current originating from the diaphragm-containing electrolysis section E2 is represented as "1-y." Applying the above "x" and "y" to formula (b) in Figure 3 + reaction formula (c) in Figure 3 + formula (g) in Figure 3 and taking into account the change shown in (e) in Figure 3, reaction formula (a) in Figure 4 is obtained.

[0058] When membrane-less electrolysis is performed in the membrane-less electrolysis section E1, chloride ions (Cl － ) is consumed and decreases, but in the space purification device 1 according to the first embodiment, chloride ions (Cl － ) is supplied.

[0059] Here, the amount of chloride ions (Cl) consumed by membraneless electrolysis is － ) from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10, －) is supplied to the electrolytic cell 10, and chloride ions (Cl － The conditions under which the apparent increase or decrease in the concentration of ClO is not observed are as follows: In this reaction, hypochlorous acid (HClO) evaporates as a gas, so it is not shown in the reaction formulas (b) to (g) shown in Figure 4. Reaction formula (b) in Figure 4: Cl － This shows the condition under which there is no apparent increase or decrease. Conditional formula (c) in Figure 4: This shows the conditional formula for coefficients x and y obtained by modifying reaction formula (b) in Figure 4. Reaction formula (d) in Figure 4: This shows the reaction formula when conditional formula (c) in Figure 4 is substituted into reaction formula (a) in Figure 4. Reaction formula (e) in Figure 4: This shows the reaction formula when reaction formula (d) in Figure 4 is modified.

[0060] According to reaction formula (e) in Figure 4, for example, when two electrons flow into the diaphragm-less electrolysis unit E1, one hypochlorous acid (HClO) is generated. For example, when four electrons flow into the diaphragm-less electrolysis unit E1, one oxygen is generated. For example, when two electrons flow into the diaphragm-less electrolysis unit E1, one hydrogen is generated.

[0061] In addition, since the acid dissociation constant of hypochlorous acid (HClO) is approximately 7.5, it is necessary to maintain the pH of the first aqueous solution L1 constant. In reaction formula (e) of FIG. 4, hydroxide ions and hydrogen ions, which are factors in the increase or decrease of pH, react to form water and disappear from the reaction formula. Therefore, the amount of chloride ions (Cl ) consumed by membraneless electrolysis is － ) from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10, － ) is supplied, and Cl is added to the electrolytic cell 10. － When the condition is such that there is no apparent increase or decrease in pH, the increase or decrease in pH can also be suppressed.

[0062] As described above, when the number of electrons flowing in the membraneless electrolysis section E1 changes, that is, when the ratio of the current flowing in the membraneless electrolysis section E1 to the current flowing in the membraneless electrolysis section E2 changes, the amount of chloride ions supplied from the supply tank 20 to the electrolytic tank 10 changes. For example, when the ratio of the current used in membraneless electrolysis changes, the amount of chloride ions (Cl － ) is supplied to the electrolytic cell 10, and Cl －is greater than the current rate under the condition that there is no apparent increase or decrease (reaction formula (f) in FIG. 4 ), the Cl － The supply amount of Cl in the electrolytic cell 10 decreases. － decreases.

[0063] Cl in the electrolytic cell 10 － If the electrolysis without a diaphragm is continued in a state where the electrolysis efficiency is reduced, the Cl in the electrolytic cell 10 will gradually decrease. － increases, and Cl － reaches a level that does not appear to increase or decrease.

[0064] On the other hand, the amount of current used for membraneless electrolysis is such that chloride ions (Cl － ) is supplied to the electrolytic cell 10, and Cl － is larger than the current amount under the condition that there is no apparent increase or decrease (reaction formula (g) in FIG. 4), Cl supplied from supply tank 20 to electrolytic tank 10 － The supply amount of Cl in the electrolytic cell 10 increases. － increases.

[0065] Chloride ions (Cl) in the electrolytic cell 10 － ) increases, the electrolysis efficiency of membrane-less electrolysis increases. If membrane-less electrolysis is continued in a state where the electrolysis efficiency has increased, the Cl in the electrolytic cell 10 gradually increases. － decreases, and Cl － reaches a level that does not appear to increase or decrease.

[0066] 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 (f) in FIG. 3 shifts to the left side, and the amount of chlorine generated increases. － By adjusting the current flowing through the membraneless electrolysis section E1 and the current flowing through the membrane-containing electrolysis section E2 so that the apparent increase or decrease in the current does not occur, hypochlorous acid can be produced while suppressing the generation of chlorine.

[0067] [Diaper membrane electrolysis section E2] Fig. 5 is a list of reaction formulae that occur in the diaphragm membrane electrolysis section E2. The reactions in the second aqueous solution L2 in the supply tank 20 will be described. The only electrode arranged in the supply tank 20 is the supply tank side cathode 21. When a predetermined voltage is applied to the diaphragm membrane electrolysis section E2, a current flows, electrons move, and the chemical reaction shown in Fig. 5 occurs. Reaction formula (a) in Fig. 5: Electrolytic tank side cathode 12 (hydrogen generation reaction) At the supply tank side cathode 21, water (H ２ O) is electron (e － ) and hydrogen (H ２ ) and hydroxide ions (OH － ) is generated. Hydrogen volatilizes as a gas, and hydroxide ions are used in the reaction formula 5(c) described later. ・(b) of FIG. 5: When a voltage is applied to the anion exchange membrane 30 and a current flows in the membrane electrolysis section E2, chloride ions (Cl － ) passes through the anion exchange membrane 30 and is supplied to the first aqueous solution L1, and the second aqueous solution L2 passes through the supply tank side cathode 21 and receives electrons (e － In other words, in the second aqueous solution L2, the chloride ions (Cl － ) after the change, electrons (e － ) in the reaction formula (c) of FIG. 5: In the second aqueous solution L2 (magnesium hydroxide precipitation reaction) The magnesium ions (Mg ２＋ ) and hydroxide ions (OH － ) reacts with magnesium hydroxide (Mg(OH) ２ ) precipitate is formed. Magnesium hydroxide (Mg(OH) ２ ) is solubility product Ksp = 1.2 × 10 －１１ (mol / L) ３ For example, magnesium hydroxide is soluble in a weakly alkaline aqueous solution with a pH of 10, at only 1.2 × 10 －３ In the second aqueous solution L2 of the supply tank 20, hydroxide ions (OH －) is used to generate magnesium hydroxide precipitate, thereby generating hydroxide ions (OH － ) and the increase in pH of the second aqueous solution L2 can be suppressed.

[0068] Furthermore, when a magnesium chloride aqueous solution is used as the second aqueous solution L2, the pH of the magnesium hydroxide saturated aqueous solution produced after membrane electrolysis, in which magnesium hydroxide is saturated, is pH 10.36 as determined from the solubility product. Therefore, even after membrane electrolysis is performed over a long period of time, the pH of the second aqueous solution L2 can be maintained in a weakly alkaline state of up to 10.36 or less. In other words, when a magnesium chloride aqueous solution is used as the second aqueous solution L2, the pH of the second aqueous solution L2 can be prevented from becoming strongly alkaline, i.e., pH 11 or higher. Therefore, a space purification device can be provided that prevents the second aqueous solution L2 from becoming strongly alkaline, thereby improving safety.

[0069] Furthermore, for example, the space purification device 1 according to the first embodiment may be installed by a contractor. After use of the space purification device 1, the space purification device 1 may be overturned or dropped when the contractor removes the installed space purification device or when transporting the removed space purification device. Here, when a magnesium chloride aqueous solution is used as the second aqueous solution L2, the second aqueous solution L2 after the electrolysis reaction is a weakly alkaline magnesium hydroxide aqueous solution. Therefore, even if the second aqueous solution L2 leaks outside the space purification device 1 due to overturning or dropping, safety can be improved compared to a space purification device using a sodium chloride aqueous solution as the second aqueous solution L2.

[0070] The above is a detailed description of the chemical reaction occurring in the membraneless electrolysis section E1 provided in the electrolytic cell 10 and the chemical reaction occurring in the membrane-containing electrolysis section E2 provided across the electrolytic cell 10 and the supply cell 20.

[0071] The current control unit 40 controls the chemical reaction by controlling the first current and the second current. More specifically, the second current is controlled to replenish the chloride ions contained in the first aqueous solution L1 that have been reduced by the diaphragm-less electrolysis in the diaphragm-less electrolysis unit E1. By controlling the second current, chloride ions contained in the second aqueous solution L2 are permeated through the anion exchange membrane 30 and supplied to the first aqueous solution L1. Details will be described below with reference to FIG. 6.

[0072] 6 is a block diagram showing the current control unit 40 according to embodiment 1. As shown in FIG. 6, the current control unit 40 includes a voltage acquisition unit 41, a calculation unit 42, and an estimation unit 43.

[0073] The voltage acquisition unit 41 acquires the voltage between the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12. The voltage acquisition 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 acquisition 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.

[0074] The current control unit 40 controls the first current passed through the membraneless electrolysis unit E1 and the second current passed through the membrane-containing electrolysis unit E2 shown in Fig. 6 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.

[0075] [1. When the First Current and the Second Current are Simultaneously Passed] When the current control unit 40 simultaneously passes the first current and the second current, it performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is lower than a predetermined concentration: The current ratio between the first current and the second current is changed so as to increase the amount of chloride ions that permeate from the second aqueous solution L2 through the anion exchange membrane 30 and are supplied to the first aqueous solution L1. More specifically, the current ratio of the first current is decreased and the current ratio of the second current is increased. (2) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is higher than a predetermined concentration: The current ratio between the first current and the second current is changed so as to decrease the amount of chloride ions that permeate from the second aqueous solution L2 through the anion exchange membrane 30 and are supplied to the first aqueous solution L1. More specifically, the current ratio of the first current is increased and the current ratio of the second current is decreased. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is a predetermined concentration: the current ratio between the first current and the second current is not changed.

[0076] [2. Case where the first current flows at a predetermined value and the second current is controlled simultaneously] When the current control unit 40 flows the first current at a predetermined value and controls the second current simultaneously, the following controls (1) to (3) are performed. (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 second current is flowed so as to increase the amount of chloride ions that permeate the anion exchange membrane 30 from the second aqueous solution L2 and are supplied to the first aqueous solution L1. (2) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is higher than a predetermined concentration: the second current is stopped so as to stop the supply of chloride ions from the second aqueous solution L2 to the first aqueous solution L1. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is a predetermined concentration: the first current and the second current are not changed.

[0077] [3. When the First Current or the Second Current is Passed] When the current control unit 40 passes the first current or the second current, it performs the following control (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 passed simultaneously so as to increase the amount of chloride ions that permeate the anion exchange membrane 30 from the second aqueous solution L2 and are supplied to the first aqueous solution L1. (2) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is higher than a predetermined concentration: The second current is stopped and the first current is passed simultaneously so as to stop the supply of chloride ions from the second aqueous solution L2 to the first aqueous solution L1. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is a predetermined concentration: The first current and the second current are not changed.

[0078] As described above, the current control unit 40 controls the first current and the second current, so that the required amount of chloride ions can be supplied to the first aqueous solution L1 in the electrolytic cell 10, and the chloride ion concentration in the first aqueous solution L1 can be maintained at a predetermined concentration.

[0079] In the above-mentioned "1. When the first current and the second current are passed simultaneously," if there is an increase or decrease in the chloride ion concentration of the first aqueous solution L1, the current control unit 40 controls to change the current ratio between the first current and the second current. Since the first current and the second current are passed simultaneously, the increase or decrease in the chloride ion concentration of the first aqueous solution L1 can be minimized, and the chloride ion concentration can be maintained at an optimum predetermined concentration.

[0080] In the above-mentioned "2. When the first current is passed at a predetermined value and the second current is controlled at the same time," if the chloride ion concentration of the first aqueous solution L1 increases or decreases, the current control unit 40 mainly controls to pass or stop the second current. In the above-mentioned "3. When the first current or the second current is passed," if the chloride ion concentration of the first aqueous solution L1 increases or decreases, the current control unit 40 controls to pass either the first current or the second current and stop the other. Therefore, the chloride ion concentration of the first aqueous solution L1 can be maintained at a predetermined concentration. In the above-mentioned cases 2 and 3, it is only necessary to control either the first current or the second current, so current control is easy.

[0081] As described above, the chloride ions consumed by the first aqueous solution L1 can be appropriately supplied from the second aqueous solution L2, thereby providing the space purification device 1 capable of stably generating a desired amount of hypochlorous acid gas. Therefore, the space purification device 1 can be provided that can stably generate a desired amount of hypochlorous acid gas for a long period of time, such as one year, without supplying an aqueous solution containing chloride ions from the outside.

[0082] It is also possible to provide a plurality of current control units 40 and control the first current and the second current separately.

[0083] In addition, in FIG. 2 , the inlet 15 and the outlet 17 are arranged on the front left side (negative side of the y-axis and negative side of the x-axis) and the back right side (positive side of the y-axis and positive side of the x-axis) when the electrolytic cell 10 is viewed in plan, 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. By arranging them in this way, the time during which the inflowing air and hypochlorous acid are mixed in the mixing space 16 is longer, and therefore, more hypochlorous acid can be contained in the mixed air.

[0084] Next, a case will be described in which plane P1 (the yz plane on the positive x-axis side) of the rectangular plate on the anion exchange membrane 30 side of the electrolytic cell-side anode plate 11 and plane P2 (the yz plane on the negative x-axis side) of the rectangular plate on the anion exchange membrane 30 side of the supply cell-side cathode plate 21 do not face each other. When the planes of each rectangle are arranged parallel to the xy plane, a non-uniform electric field may be generated between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21. When a non-uniform electric field is generated between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21, the current distribution between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21 also becomes non-uniform.

[0085] When the current distribution between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21 becomes uneven, regions of high and low current density are generated. In the high current density areas, the catalytic layer on the surfaces of the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21 (hereinafter also referred to as each electrode plate) is more likely to deteriorate. On the other hand, in the low current density areas, the catalytic layer on the surfaces of each electrode plate is less likely to deteriorate. That is, when an uneven electric field is generated between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21, the current distribution becomes uneven, 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 unevenly. If the degree of deterioration of the catalytic layer on the surface of each electrode plate differs, repeated electrolysis may result in the simultaneous existence of regions on each electrode plate that can be used as an electrode and regions that have deteriorated to the point where they are unusable due to advanced deterioration. When electrolysis is performed using electrode plates that include regions that cannot be used as electrodes, the electrolysis efficiency may be easily reduced.

[0086] In contrast, in the spatial purification device 1 according to the first embodiment, the planes P1 and P2 are arranged opposite each other with the anion exchange membrane 30 interposed therebetween. This arrangement allows a uniform electric field to be generated between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21, resulting in a uniform distribution of current between the two electrodes. Therefore, deterioration of the catalyst layer on the surface of each electrode plate occurs uniformly, and uneven deterioration of the catalyst layer on the surface of each electrode plate due to an uneven electric field can be suppressed even when electrolysis is performed repeatedly. Therefore, a decrease in electrolysis efficiency can be suppressed.

[0087] When membraneless electrolysis is performed in an electrolytic cell at room temperature and normal pressure, the electrolyte of the first aqueous solution L1 is not used in electrolysis, and oxygen and chlorine are mainly generated from the anode. The electrolyte does not react with hypochlorous acid to reduce the concentration of hypochlorous acid. It is sufficient to have electrical conductivity and not be reactive with the electrodes, the electrolytic cell, or the anion exchange membrane. More specifically, in addition to the first aqueous solution described above, the first aqueous solution L1 may be, for example, a metal chloride aqueous solution, a hydroxide salt aqueous solution, an acid salt aqueous solution, a phosphate aqueous solution, or a combination thereof. The metal chloride aqueous solution may be, for example, a dilute calcium chloride aqueous solution or a dilute magnesium chloride aqueous solution. The hydroxide salt aqueous solution may be, for example, a dilute sodium hydroxide aqueous solution or a dilute potassium hydroxide aqueous solution of 0.4 wt % (0.1 mol / L) or less. The acid salt aqueous solution may be, for example, a dilute hydrochloric acid aqueous solution of 0.4 wt % (0.1 mol / L) or less. The phosphate aqueous solution may be, for example, a disodium hydrogen phosphate aqueous solution, a sodium dihydrogen phosphate aqueous solution, a dipotassium hydrogen phosphate aqueous solution, or a potassium dihydrogen phosphate aqueous solution. As a specific example of a combination of the first aqueous solutions, the pH may be adjusted by combining a dilute aqueous sodium chloride solution with a dilute aqueous sodium hydroxide solution.

[0088] The present disclosure is not limited to the above-described first embodiment, and can be modified as appropriate within the scope of the present disclosure.

[0089] An outline of one aspect of the present disclosure is as follows.

[0090] an anion exchange membrane that is provided to connect the electrolytic cell and the supply cell and that allows anions to pass through based on a voltage applied between the electrolytic cell-side anode and the supply cell-side cathode; and a membrane-less electrolysis unit that is provided in the electrolytic cell and that generates hypochlorous acid by passing a first current between the electrolytic cell-side anode and the electrolytic cell-side cathode. (Item 1) An electrolytic cell for storing a first aqueous solution containing chloride ions; a supply cell for storing a second aqueous solution containing chloride ions at a higher concentration than the first aqueous solution and supplying chloride ions to the first aqueous solution; a housing that stores the electrolytic cell and the supply cell; an inlet that is located within the housing above the 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; an electrolytic cell-side anode and an electrolytic cell-side cathode provided in the electrolytic cell; a diaphragm-less electrolysis section provided between the electrolytic cell and the supply cell, which performs membrane-with-diaphragm electrolysis via the anion exchange membrane by passing a second current between the electrolytic cell-side anode and the supply cell-side cathode; a mixing space which mixes the volatilized hypochlorous acid with the air which has flowed in from the inlet; and an outlet through which the mixed air flows out to the external space, wherein the second aqueous solution is a metal chloride aqueous solution containing metal ions and the chloride ions; and by performing the membrane-with-diaphragm electrolysis, the chloride ions contained in the second aqueous solution stored in the supply cell are supplied through the anion exchange membrane to the first aqueous solution stored in the electrolytic cell so as to replenish the chloride ions contained in the first aqueous solution which have been reduced by the membrane-less electrolysis, and in the supply cell, the metal ions contained in the second aqueous solution and hydroxide ions generated by the membrane-with-diaphragm electrolysis react with each other to form a precipitate of metal hydroxide.

[0091] (Item 2) The space purifying device according to Item 1, wherein the second aqueous solution is a magnesium chloride aqueous solution.

[0092] (Item 3) The space purification device according to Item 1, further comprising a current control unit that controls a second current so that chloride ions contained in the second aqueous solution stored in the supply tank are supplied to the first aqueous solution stored in the electrolytic tank through the anion exchange membrane in order to replenish chloride ions contained in the first aqueous solution that have been reduced by the membrane-less electrolysis, wherein the current control unit controls the first current and the second current to flow at a predetermined ratio so as to maintain a predetermined chloride ion concentration in the first aqueous solution.

[0093] (Item 4) The space purification device according to Item 3, wherein the current control unit comprises: a voltage acquisition unit that acquires a voltage between the electrolytic cell-side anode and the electrolytic 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; and an estimation unit that estimates the concentration of the first aqueous solution based on the conductivity calculated by the calculation unit; wherein the current control unit simultaneously flows the first current and the second current; and, when a chloride ion concentration of the first aqueous solution is lower than the predetermined concentration, controls to change a current ratio between the first current and the second current so as to increase an amount of chloride ions that permeate the anion exchange membrane from the second aqueous solution and are supplied to the first aqueous solution; and, when a chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, controls to change a current ratio between the first current and the second current so as to decrease an amount of chloride ions that permeate the anion exchange membrane from the second aqueous solution and are supplied to the first aqueous solution.

[0094] (Item 5) The space purification device according to Item 4, wherein the current control unit controls the current ratio of the first current to the second current so as not to change when the chloride ion concentration of the first aqueous solution is the predetermined concentration.

[0095] (Item 6) The space purification device according to Item 3, wherein the current control unit includes: a voltage acquisition unit that acquires a voltage between the electrolytic cell-side anode and the electrolytic 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; and an estimation unit that estimates the concentration of the first aqueous solution based on the conductivity calculated by the calculation unit; wherein the current control unit controls the second current while causing the first current to flow at a predetermined value, and controls the second current by: causing the second current to flow when the chloride ion concentration of the first aqueous solution is lower than the predetermined concentration so as to increase the amount of chloride ions that permeate the anion exchange membrane from the second aqueous solution and are supplied to the first aqueous solution; and stopping the second current when the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration so as to stop the supply of chloride ions from the second aqueous solution to the first aqueous solution.

[0096] (Item 7) The space purification device according to Item 3, wherein the current control unit comprises: a voltage acquisition unit that acquires a voltage between the electrolytic cell-side anode and the electrolytic 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; and an estimation unit that estimates the concentration of the first aqueous solution based on the conductivity calculated by the calculation unit; and when a chloride ion concentration of the first aqueous solution is lower than the predetermined concentration, the current control unit controls to stop the first current and simultaneously flow the second current so as to increase an amount of chloride ions that permeate the anion exchange membrane from the second aqueous solution and are supplied to the first aqueous solution, and when a chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, the current control unit controls to stop the second current and simultaneously flow the first current so as to stop the supply of chloride ions from the second aqueous solution to the first aqueous solution.

[0097] (Item 8) The electrolytic cell-side anode, the electrolytic cell-side cathode, and the supply cell-side cathode are electrolytic cell-side anode plates, electrolytic cell-side cathode plates, and supply cell-side cathode plates, each having a plate-like shape; the electrolytic cell-side anode plates and the electrolytic cell-side cathode plates are inserted into the electrolytic cell from the outside of the electrolytic cell, and the supply cell-side cathode plate is inserted into the supply cell from the outside of the supply cell; the electrolytic cell-side anode plates comprise an electrolytic cell-side anode plate immersed portion arranged on the inside of the electrolytic cell and an electrolytic cell-side anode plate protruding portion arranged on the outside of the electrolytic cell; the electrolytic cell-side cathode plates comprise an electrolytic cell-side cathode plate immersed portion arranged on the inside of the electrolytic cell and an electrolytic cell-side cathode plate protruding portion arranged on the outside of the electrolytic cell; and the supply cell-side cathode plate comprises a supply cell-side cathode plate immersed portion arranged on the inside of the supply cell and a supply cell-side cathode plate protruding portion arranged on the outside of the supply cell. Item 2. The space purification device according to item 1, wherein the electrolytic cell-side anode plate immersed portion and the electrolytic cell-side cathode plate immersed portion are entirely immersed in the first aqueous solution, and the supply cell-side cathode plate immersed portion is entirely immersed in the second aqueous solution.

[0098] (Item 9) The space purification device according to Item 8, further comprising: a water level detection unit that detects the position of the liquid level in the first aqueous solution; and a water supply unit that supplies water to the electrolytic cell so that the position of the liquid level detected by the water level detection unit does not fall below upper ends of the electrolytic cell-side anode plate immersion portion and the electrolytic cell-side cathode plate immersion portion.

[0099] (Item 10) The space purification device according to Item 1, wherein the diaphragm-less electrolysis unit includes the electrolytic cell-side anode and the electrolytic cell-side cathode, and the diaphragm-containing electrolysis unit includes the electrolytic cell-side anode, the supply cell-side cathode, and the anion exchange membrane.

[0100] <Embodiment 2> The present disclosure provides a space purification device that can increase safety and stably supply hypochlorous acid by suppressing strong alkalinity after electrolysis of the aqueous solution stored in the supply tank.

[0101] The spatial purification device according to the present disclosure includes an electrolytic cell for storing an aqueous chloride solution containing chloride ions; a supply cell for storing an aqueous magnesium chloride solution containing chloride ions at a higher concentration than the aqueous chloride solution and supplying chloride ions to the aqueous chloride solution; an electrolytic cell-side anode and an electrolytic cell-side cathode provided in the electrolytic cell; a supply cell-side cathode provided in the supply cell; an anion exchange membrane provided to connect the electrolytic cell and the supply cell and allowing anions to pass therethrough based on a voltage applied between the electrolytic cell-side anode and the supply cell-side cathode; and a first current source provided in the electrolytic cell and configured to generate a first current between the electrolytic cell-side anode and the electrolytic cell-side cathode. the electrolysis unit includes a diaphragm-less electrolysis unit that generates hypochlorous acid by performing diaphragm-less electrolysis of an aqueous chloride solution by passing a second current between the electrolytic cell-side anode and the supply cell-side cathode, a diaphragm-containing electrolysis unit that is provided between the electrolytic cell and the supply cell and performs diaphragm-containing electrolysis via an anion exchange membrane by passing a second current between the electrolytic cell-side anode and the supply cell-side cathode, and a current control unit that controls the current so that chloride ions contained in the aqueous magnesium chloride solution stored in the supply cell pass through the anion exchange membrane and are supplied to the aqueous chloride solution stored in the electrolytic cell so as to replenish chloride ions contained in the aqueous chloride solution that have decreased due to the diaphragm-less electrolysis. By performing the diaphragm-containing electrolysis, magnesium ions contained in the aqueous magnesium chloride solution react with hydroxide ions produced by the diaphragm-containing electrolysis in the supply cell to form a precipitate of magnesium hydroxide. The current control unit controls the first current and the second current to flow at a predetermined current ratio so that chloride ions contained in the aqueous magnesium chloride solution stored in the supply tank are passed through the anion exchange membrane and supplied to the aqueous chloride solution stored in the electrolytic tank, and controls to change the current ratio of the first current and the second current within a predetermined range of the total current amount according to the amount of magnesium hydroxide precipitated so that the chloride ion concentration in the aqueous chloride solution is maintained at a predetermined concentration.

[0102] The present disclosure makes it possible to provide a space purification device that can increase safety by suppressing strong alkalinity after electrolysis of an aqueous solution and can stably supply hypochlorous acid.

[0103] A specific second embodiment of the present disclosure will be described in detail below with reference to the drawings.

[0104] The right-handed xyz coordinate system shown in the drawings is for the convenience of explaining the positional relationships of the components. Unless otherwise specified, the positive direction of the z axis is vertically upward. The xy plane is a horizontal plane, and is common to all drawings.

[0105] 7 is a perspective view showing an outline of the space purification device 101 according to embodiment 2. The space purification device 101 electrolyzes a chloride aqueous solution L10 containing chloride ions in an electrolytic cell 110 (described later) to generate and volatilize hypochlorous acid. The space purification device 101 removes bacteria, fungi, viruses, odors, and the like contained in the air in the external space of the space purification device 101 by discharging the volatilized hypochlorous acid into the external space of the housing B10 constituting the space purification device 101.

[0106] The space purification device 101 is installed indoors. The installation location of the space purification device 101 is preferably a location where air flow can occur. More specifically, the installation locations of the space purification device 101 include, for example, inside an air conditioner, which is an air conditioner, around an electric fan, around a circulator, around a ceiling fan, inside a humidifier, inside an air purifier, and on a desk.

[0107] The spatial purification device 101 includes a housing B 10 , an electrolytic cell 110 , a supply cell 120 , an anion exchange membrane 130 , and a current control unit 140 .

[0108] The housing B10 houses the electrolytic cell 110, the supply cell 120, the anion exchange membrane 130, and the current control unit 140. That is, the space purification device 101 may be an integrated unit formed by the housing B10. The shape of the housing B10 can be changed appropriately depending on the location where the space purification device 101 is installed, and may be, for example, a rectangular parallelepiped or cylindrical shape. The space purification device 1 has a small size that can be stored inside an air conditioner, for example, approximately 10 cm x 7 cm x 4 cm.

[0109] The electrolytic bath 110 is a bath for storing an aqueous chloride solution L10 containing chloride ions. The electrolytic bath 110 has, for example, a box-like shape. FIG. 7 shows a state in which the aqueous chloride solution L10 is stored in the electrolytic bath 110. The aqueous chloride solution L10 is, for example, an aqueous solution in which an electrically conductive electrolyte is dissolved, and specifically, a dilute aqueous chloride solution having a predetermined chloride ion concentration. More specifically, the aqueous chloride solution L10 is, for example, a sodium chloride aqueous solution or a dilute potassium chloride aqueous solution.

[0110] The "predetermined chloride ion concentration" of the chloride aqueous solution L10 includes both a chloride ion concentration having a predetermined numerical range and a chloride ion concentration having a predetermined numerical value. More specifically, the chloride ion concentration of the chloride aqueous solution L10 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 dilute potassium chloride aqueous solution may be, for example, 0.1% to 5%, or may be 5%. By setting the predetermined chloride ion concentration to this numerical range or numerical value, it is possible to generate hypochlorous acid necessary for space purification while simultaneously suppressing the generation of chlorine, which may be generated.

[0111] The supply tank 120 is a tank for storing an aqueous magnesium chloride solution L20 containing chloride ions. The chloride ions contained in the aqueous magnesium chloride solution L20 in the supply tank 120 permeate through the anion exchange membrane 130 and are supplied to the aqueous chloride solution L10 in the electrolytic tank 110.

[0112] The supply tank 120 is a tank for storing an aqueous magnesium chloride solution L20 containing chloride ions and supplying the chloride ions to the chloride aqueous solution L10. FIG. 7 shows a state in which the aqueous magnesium chloride solution L20 is stored in the supply tank 120. The chloride ion concentration of the aqueous magnesium chloride solution L20 is higher than that of the aqueous chloride solution L10. When the magnesium chloride aqueous solution L20 undergoes diaphragm electrolysis, as described below, the magnesium ions contained in the aqueous magnesium chloride solution L20 react with the hydroxide ions generated by the diaphragm electrolysis to form a magnesium hydroxide precipitate. The "precipitate" of magnesium hydroxide includes hard sand, colloid, slurry, or gel, and includes a cloudy aqueous solution. As the formation of magnesium hydroxide precipitates progresses, the aqueous magnesium chloride solution L20 becomes increasingly cloudy, and the fluidity of the solution decreases. Preferably, the aqueous magnesium chloride solution L20 is a high-concentration aqueous magnesium chloride solution or a saturated aqueous magnesium chloride solution. The mass percent concentration of the magnesium chloride aqueous solution L20 is, for example, 10% to 35%.

[0113] Assuming continuous use for eight hours every day for one year, the respective volumes of the electrolytic cell 110 and the supply cell 120 are preferably such that, for example, the volume of the supply cell 120 is at least about 12 times the volume of the electrolytic cell 110. By setting such a volume ratio, the supply cell 120 can store an aqueous magnesium chloride solution L20 containing a sufficient amount of chloride ions necessary for supply to the aqueous chloride solution L10 in the electrolytic cell 110. Therefore, chloride ions can be stably supplied from the aqueous magnesium chloride solution L20 stored in the supply cell 120 to the aqueous chloride solution L10 stored in the electrolytic cell 110. The amount of the aqueous chloride solution L10 stored in the electrolytic cell 110 is, for example, about 2 to 10 mL.

[0114] The anion exchange membrane 130 is provided to connect the electrolytic cell 110 and the supply cell 120, and is a membranous member that allows anions to pass therethrough based on a voltage applied between the electrolytic cell 110 and the supply cell 120. More specifically, when a voltage is applied between the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121 (described below), membrane-operated electrolysis is carried out via the anion exchange membrane 130. By membrane-operated electrolysis using the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121, chloride ions contained in the magnesium chloride aqueous solution L20 permeate the anion exchange membrane 130 and are supplied to the chloride aqueous solution L10 (indicated by a thick black arrow in the negative direction of the x-axis).

[0115] The anion exchange membrane 130 in the second embodiment is not a type of anion exchange membrane through which anions permeate due to osmotic pressure without using electricity. Furthermore, the anion exchange membrane 130 does not allow magnesium ions, which are cations, to permeate. More specifically, when chloride ions contained in the magnesium chloride aqueous solution L20 permeate the anion exchange membrane 130 and are supplied to the chloride aqueous solution L10 by membrane electrolysis using the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121, magnesium ions, which are cations, do not permeate the anion exchange membrane 130. The anion exchange membrane 130 is, for example, a hydrocarbon-based anion exchange membrane. Specific examples of hydrocarbon-based anion exchange membranes include membranes that have monovalent anion-selective permeability, alkali resistance, or high-temperature resistance.

[0116] The anion exchange membrane 130 is disposed between the electrolytic cell 110 and the supply cell 120. For example, the surface of the electrolytic cell 110 facing the supply cell 120 (the yz plane on the positive side of the x-axis) and the surface of the supply cell 120 facing the electrolytic cell 110 (the yz plane on the negative side of the x-axis) may each be formed by a frame-shaped member. When the opposing surfaces of the electrolytic cell 110 and the supply cell 120 are formed by frame-shaped members, the anion exchange membrane 130 may be disposed so as to be fitted into the frame-shaped member.

[0117] The current control unit 140 controls the current used in the diaphragmless electrolysis and the diaphragm-containing electrolysis. More specifically, the current control unit 140 controls the current used in the diaphragmless electrolysis, which is performed using a pair of electrolytic cell-side anodes 111 and electrolytic cell-side cathodes 112 arranged in the electrolytic cell 110. The current control unit 140 also controls the current used in the diaphragm-containing electrolysis, which is performed via an anion exchange membrane 130 using a pair of electrolytic cell-side anodes 111 and feed cell-side cathodes 121, across the electrolytic cell 110 and the feed cell 120. The electrolytic cell-side anode 111 is used for both the diaphragm-less electrolysis and the diaphragm-containing electrolysis. That is, the space purification device 101 according to the second embodiment includes one anode and two cathodes, for a total of three electrodes. Because the feed cell 120 includes only a cathode, chlorine is not generated in the feed cell 120 by a chemical reaction, which will be described later.

[0118] Hereinafter, the details of each component will be described in more detail with reference to FIGS.

[0119] As shown in FIG. 7, the electrolytic cell 110 includes an electrolytic cell-side anode 111 , an electrolytic cell-side cathode 112 , a wire 113 , a wire 114 , an inlet 115 , a mixing space 116 , and an outlet 117 .

[0120] The electrolytic cell-side anode 111 and the electrolytic cell-side cathode 112 are a pair of electrodes used in the electrolysis of the aqueous chloride solution L10. As shown in Fig. 7 , no diaphragm such as an ion exchange membrane is provided between the electrolytic cell-side anode 111 and the electrolytic cell-side cathode 112. In other words, the electrolysis of the aqueous chloride solution L10 performed using the pair of the electrolytic cell-side anode 111 and the electrolytic cell-side cathode 112 is membrane-less electrolysis. Hypochlorous acid, which is used for space purification, is produced by the membrane-less electrolysis of the aqueous chloride solution L10 performed using the pair of the electrolytic cell-side anode 111 and the electrolytic cell-side cathode 112.

[0121] The electrolytic cell-side anode 111 and the electrolytic cell-side cathode 112 each have a plate-like shape. That is, the electrolytic cell-side anode 111 is an electrolytic cell-side anode plate 111 having a plate-like shape, and the electrolytic cell-side cathode 112 is an electrolytic cell-side cathode plate 112 having a plate-like shape. Plate-like shapes include rectangular and oblong shapes. Hereinafter, the electrolytic cell-side anode 111 will also be referred to as the electrolytic cell-side anode plate 111. The electrolytic cell-side cathode 112 will also be referred to as the electrolytic cell-side cathode plate 112.

[0122] As an example, a case will be described in which the plate shapes of the electrolytic cell-side anode plate 111 and the electrolytic cell-side cathode plate 112 are rectangular. The electrolytic cell-side anode plate 111 and the electrolytic cell-side cathode plate 112 are arranged such that the shorter side of the rectangle is aligned with the vertical direction (z-axis direction). This arrangement can prevent bubbles generated by chemical reactions from adhering to both sides of the rectangle of each electrode. Furthermore, compared to when the longer side of the rectangle is aligned with the vertical direction (z-axis direction), when the shorter side is aligned with the vertical direction (z-axis direction), bubbles generated at the lower part (negative side of the z-axis) of the electrolytic cell-side anode plate 111 and the electrolytic cell-side cathode plate 112 are prevented from adhering to the upper part (positive side of the z-axis) of the electrolytic cell-side anode plate 111 and the electrolytic cell-side cathode plate 112.

[0123] The electrolytic cell-side anode plate 111 and the electrolytic cell-side cathode plate 112 are arranged such that the longitudinal direction of the rectangle is along the horizontal direction (y-axis direction). In other words, the electrolytic cell-side anode plate 111 and the electrolytic cell-side cathode plate 112 are arranged such that the planes (yz planes) of their respective rectangles face each other with a predetermined gap between them. The predetermined gap is a gap appropriate for electrolysis performed using a pair of electrolytic cell-side anode plate 111 and electrolytic cell-side cathode plate 112.

[0124] The electrolytic cell-side anode plate 111 has an electrolytic cell-side anode plate immersed portion 111a and an electrolytic cell-side anode plate protruding portion 111b. Similarly, the electrolytic cell-side cathode plate 112 has an electrolytic cell-side cathode plate immersed portion 112a and an electrolytic cell-side cathode plate protruding portion 112b.

[0125] The electrolytic cell-side anode plate 111 and the electrolytic cell-side cathode plate 112 are inserted from the outside of the electrolytic cell 110 toward the inside. In FIG. 7 , as an example, the electrolytic cell-side anode plate 111 and the electrolytic cell-side cathode plate 112 are inserted from the side of the electrolytic cell 110 (the xz plane side on the negative side of the y axis) toward the horizontal direction (y axis direction). The electrolytic cell-side anode plate immersed portion 111a and the electrolytic cell-side cathode plate immersed portion 112a inserted into the electrolytic cell 110 are positioned inside the electrolytic cell 110 and are entirely immersed in the aqueous chloride solution L10. In other words, the aqueous chloride solution L10 is stored in the electrolytic cell 110 so that the entire electrolytic cell-side anode plate immersed portion 111a and the entire electrolytic cell-side cathode plate immersed portion 112a are immersed. That is, the chloride aqueous solution L10 is stored in the electrolytic cell 110 so that the liquid level S10 of the chloride aqueous solution L10 exceeds the upper ends (ends on the positive side of the z-axis) of the electrolytic cell side anode plate immersed portion 111a and the electrolytic cell side cathode plate immersed portion 112a.

[0126] The electrolytic cell-side anode plate protrusion 111b and the electrolytic cell-side cathode plate protrusion 112b are disposed on the exterior side of the electrolytic cell 110. Wiring 113 and wiring 114 are lines through which current flows. The electrolytic cell-side anode plate protrusion 111b is electrically connected to a current control unit 140 via wiring 113, and the electrolytic cell-side cathode plate protrusion 112b is electrically connected to a current control unit 140 via wiring 114.

[0127] The electrolytic cell side anode plate 111 and the electrolytic cell side cathode plate 112 may be, for example, a platinum iridium titanium electrode, a platinum electrode, a ruthenium titanium electrode, or an iridium titanium oxide electrode.

[0128] The inlet 115 is an opening through which air from the space outside the casing B10 flows in. That is, the inlet 115 is an opening through which air from the space outside the space purification device 101 flows in. In FIG. 7 , as an example, the inlet 115 is provided on the top surface (xy plane on the positive side of the z-axis) of the electrolytic bath 110, but it may be located above the liquid level S10 of the chloride aqueous solution L10. The shape of the inlet 115 may be, for example, cylindrical as shown in FIG. 7 or rectangular tubular. When the top surface (the surface on the positive side of the z-axis) of the electrolytic bath 110 is close to the ceiling surface of the casing B10, the inlet 115 may be a hole-like opening provided in a part of the top surface of the electrolytic bath 110. Furthermore, the inlet 115 and the top surface (the surface on the positive side of the z-axis) of the casing B10 may be integrally formed.

[0129] The mixing space 116 is a space formed above the electrolytic cell 110 (positive side of the z-axis) when the chloride aqueous solution L10 is stored in the electrolytic cell 110. The mixing space 116 is a space for mixing hypochlorous acid generated by membrane-less electrolysis of the chloride aqueous solution L10 using a pair of electrolytic cell-side anode plates 111 and electrolytic cell-side cathode plates 112 with air from the external space that flows in through the inlet 115. The hypochlorous acid generated by membrane-less electrolysis includes volatilized and gasified hypochlorous acid gas and hypochlorous acid dissolved in the chloride aqueous solution L10. The hypochlorous acid gas is contained in the air that flows in through the inlet 115 and flows out to the external space through the outlet 117, which will be described later. The hypochlorous acid dissolved in the chloride aqueous solution L10 flows out to the external space through the outlet 117, which will be described later, by gas-liquid contact with the air that flows in through the inlet 115.

[0130] The outlet 117 is an opening through which mixed air, which is a mixture of air flowing in from the inlet 115 and hypochlorous acid generated by the membraneless electrolysis of the chloride aqueous solution L10, flows out to the space outside the casing B10. That is, the outlet 117 is an opening through which the mixed air flows out to the space outside the space purification device 101. In FIG. 7 , the outlet 117 is provided on the top surface (xy plane on the positive side of the z-axis) of the electrolytic cell 110 as an example, similar to the inlet 115, but it need only be located above the liquid level of the chloride aqueous solution L10. The shape of the outlet 117 is similar to that of the inlet 115 and may be, for example, cylindrical as shown in FIG. 7 or rectangular tubular. When the top surface (the surface on the positive side of the z-axis) of the electrolytic cell 110 is close to the ceiling surface of the casing B10, the outlet 117 may be a hole-like opening provided in a portion of the top surface of the electrolytic cell 110. Furthermore, the outlet 117 and the upper surface (the surface on the positive side of the z-axis) of the housing B10 may be formed integrally.

[0131] The inlet 115 and the outlet 117 may be provided with a lid (not shown) that can be opened or closed or that can be removed. The lid may be configured to be closed when the space purification device 101 is transported, moved, or installed, and to be opened or removed when the space purification device 101 is used. Although the inlet 115 and the outlet 117 are described as having separate structures, the inlet 115 and the outlet 117 may each serve as both an inlet and an outlet depending on the direction of wind flowing into the space purification device 101.

[0132] The air containing hypochlorous acid that flows out from the outlet 117 into the space outside the space purification device 101 purifies the 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 B10.

[0133] The supply tank 120 includes a supply tank-side cathode 121, wiring 122, and an outlet 123. The supply tank-side cathode 121 is an electrode paired with the electrolytic cell-side anode 111 and used for electrolysis of the aqueous magnesium chloride solution L20. As shown in FIG. 7 , an anion exchange membrane 130 is disposed between the electrolytic cell-side anode 111 and the supply tank-side cathode 121. That is, the electrolysis of the aqueous magnesium chloride solution L20 performed using the pair of the electrolytic cell-side anode 111 and the supply tank-side cathode 121 is membrane-less electrolysis. That is, the electrolytic cell-side anode 111 is used for both membrane-less electrolysis and membrane-with electrolysis. Chloride ions are supplied from the aqueous magnesium chloride solution L20 to the chloride solution L10 by the membrane-with electrolysis of the aqueous magnesium chloride solution L20 performed using the pair of the electrolytic cell-side anode 111 and the supply tank-side cathode 121.

[0134] The supply tank side cathode 121 is a supply tank side cathode plate 121 having a plate shape. The plate shape includes a rectangular shape and an oblong shape. Hereinafter, the supply tank side cathode 121 will also be referred to as a supply tank side cathode plate 121.

[0135] As an example, a case will be described in which the supply tank side cathode plate 121 is also rectangular in shape, similar to the electrolytic tank side anode plate 111. As shown in Fig. 7 , the supply tank side cathode plate 121 is arranged such that the shorter side of the rectangle is aligned vertically (z-axis direction). Furthermore, the supply tank side cathode plate 121 is arranged such that the longer side of the rectangle is aligned horizontally (y-axis direction).

[0136] The electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121 are each in close proximity to the anion exchange membrane 130. In this specification, "close proximity" includes both a state in which the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121 are close to the anion exchange membrane 130 with a predetermined gap therebetween, and a state in which the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121 are each in contact with the anion exchange membrane 130.

[0137] The plane of the rectangular plate on the anion exchange membrane 130 side of the electrolytic cell-side anode plate 111 (the yz plane on the positive x-axis side) is designated as plane P10. The plane of the rectangular plate on the anion exchange membrane 130 side of the supply cell-side cathode plate 121 (the yz plane on the negative x-axis side) is designated as plane P20. Planes P10 and P20 are arranged opposite each other with the anion exchange membrane 130 interposed between them. This arrangement allows a uniform electric field to be generated between the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121.

[0138] The electrolytic cell-side anode plate 111 is disposed between the electrolytic cell-side cathode plate 112 and the anion exchange membrane 130. This arrangement makes it possible to maintain small potential differences between the electrolytic cell-side anode plate 111 and the electrolytic cell-side cathode plate 112, and between the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121.

[0139] The supply tank side cathode plate 121 includes a supply tank side cathode plate immersion portion 121a and a supply tank side cathode plate protrusion portion 121b. The supply tank side cathode plate 121 is inserted from the outside of the electrolytic cell 110 toward the inside. In FIG. 7 , as an example, the supply tank side cathode plate 121 is inserted from the side of the electrolytic cell 110 (the xz plane side on the negative side of the y axis) toward the horizontal direction (y axis direction). The supply tank side cathode plate immersion portion 121a inserted into the supply tank 120 is positioned inside the supply tank 120 and is entirely immersed in the aqueous magnesium chloride solution L20. In other words, the aqueous magnesium chloride solution L20 is stored in the supply tank 120 so that the entire supply tank side cathode plate immersion portion 121a is immersed. That is, the magnesium chloride aqueous solution L20 is stored in the supply tank 120 so that the liquid level S20 of the magnesium chloride aqueous solution L20 exceeds the upper end (the end on the positive z-axis side) of the supply tank side cathode plate immersed portion 121a.

[0140] 7, the supply tank side cathode plate protrusion 121b is disposed on the exterior side of the supply tank 120. The wiring 122 is a line through which current flows. The supply tank side cathode plate protrusion 121b is electrically connected to the current control unit 140 via the wiring 122.

[0141] As the supply tank side cathode plate 121, 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.

[0142] The outlet 123 is an opening for discharging hydrogen gas generated by the diaphragm electrolysis of the magnesium chloride aqueous solution L20 to the external space of the casing B10. The outlet 123 may be, for example, a check valve. When a check valve is used as the outlet 123, hydrogen gas inside the supply tank 120 is discharged to the external space, but the inflow of gases such as air from the external space can be suppressed. When the diaphragm electrolysis of the magnesium chloride aqueous solution L20 is repeated, hydrogen gas accumulates inside the supply tank 120, and the internal pressure of the supply tank 120 increases. This increase in pressure opens the check valve, and hydrogen gas is discharged to the external space of the supply tank 120.

[0143] Figure 8 is a partial front cross-sectional view showing the space purification device 101 of Figure 7. The housing B10 shown in Figure 7 is omitted from Figure 8. As shown in Figure 8, the space purification device 101 may further include a water level detection unit 118 and a water supply unit 119. The water level detection unit 118 detects the position of the liquid level S10 in the chloride aqueous solution L10. The water level detection unit 118 is, for example, a water level sensor. The water level detection unit 118 is disposed above (on the positive z-axis side) the upper ends (on the positive z-axis side) of at least the electrolytic cell-side anode plate immersed portion 111a, the electrolytic cell-side cathode plate immersed portion 112a, and the supply cell-side cathode plate immersed portion 121a.

[0144] The water supply unit 119 supplies water to the electrolytic cell 110 based on the position of the liquid level S10 detected by the water level detection unit 118. More specifically, the water supply unit 119 supplies water to the electrolytic cell 110 so that the water level does not fall below the upper ends (portions on the positive side of the z-axis) of the electrolytic cell-side anode plate immersed portion 111a, the electrolytic cell-side cathode plate immersed portion 112a, and the supply cell-side cathode plate immersed portion 121a. The water supply unit 119 may be, for example, a Peltier element that can cool and condense moisture contained in the air into droplets, or a water tank that can store water. The water supply unit 119 may be located in any position that allows it to supply water to the electrolytic cell 110, and may be located on the top side of the electrolytic cell 110, on the side side of the electrolytic cell 110, or on the bottom side of the electrolytic cell 110.

[0145] When the spatial purification device 101 is equipped with the water level detection unit 118 and the water supply unit 119, the electrolytic cell-side anode plate immersed portion 111a and the electrolytic cell-side cathode plate immersed portion 112a can be maintained immersed in the aqueous chloride solution L10. This prevents the electrolytic cell-side anode plate immersed portion 111a and the electrolytic cell-side cathode plate immersed portion 112a from being exposed to air due to a decrease in the aqueous chloride solution L10, thereby maintaining the electrolysis efficiency of the diaphragm-less electrolysis.

[0146] 8 , the space purification device 101 according to the second embodiment includes a diaphragm-less electrolysis unit E10 and a diaphragm-containing electrolysis unit E20. The current control unit 140 controls the first current flowing through the diaphragm-less electrolysis unit E10 and the second current flowing through the diaphragm-containing electrolysis unit E20, thereby controlling the chemical reactions occurring in the diaphragm-less electrolysis unit E10 and the diaphragm-containing electrolysis unit E20.

[0147] The diaphragm-less electrolysis unit E10 is provided in the electrolytic cell 110. The diaphragm-less electrolysis unit E10 produces hypochlorous acid by performing membrane-less electrolysis of the aqueous chloride solution L10 by passing a first current between the electrolytic cell-side anode 111 and the electrolytic cell-side cathode 112. In other words, the diaphragm-less electrolysis unit E10 includes the electrolytic cell-side anode 111 and the electrolytic cell-side cathode 112.

[0148] The membrane-equipped electrolysis unit E20 is provided across the electrolytic cell 110 and the supply cell 120. A second current is passed between the electrolytic cell-side anode 111 and the supply cell-side cathode 121, thereby performing membrane-equipped electrolysis via the anion exchange membrane 130. In other words, the membrane-equipped electrolysis unit E20 includes the electrolytic cell-side anode 111, the supply cell-side cathode 121, and the anion exchange membrane 130.

[0149] Here, we will explain in detail the chemical reactions that occur in the diaphragm-less electrolysis unit E10 provided in the electrolytic cell 110 and the chemical reactions that occur in the diaphragm-containing electrolysis unit E20 provided between the electrolytic cell 110 and the supply cell 120. Below, we will explain the case where the aqueous chloride solution L10 containing chloride ions is a sodium chloride aqueous solution.

[0150] [Non-diaphragm electrolysis section E10 (electrolytic cell 110)] Fig. 9 is a list of reaction formulas occurring in the non-diaphragm electrolysis section E10. Sodium chloride (NaCl) contained in the sodium chloride aqueous solution, which is the chloride aqueous solution L10, converts sodium ions (Na ＋ ) and chloride ions (Cl － When a predetermined voltage is applied to the membraneless electrolysis unit E10, a current flows, electrons move, and chemical reactions shown in reaction formulas (a) to (g) in FIG. 9 occur. Reaction formula (a) in FIG. 9: Electrolytic cell side anode 111 (chlorine generation reaction) At the electrolytic cell side anode 111, chloride ions (Cl ) ionized in water are generated. － ) is an electron (e － ) and loses chlorine (Cl ２ 9 Reaction formula (b): Electrolytic cell side cathode 112 (hydrogen generation reaction) At the electrolytic cell side cathode 112, water (H ２ O) is electron (e － ) and hydrogen (H ２ ) and hydroxide ions (OH － 9: Electrolytic cell-side anode 111 (oxygen generation reaction) At the electrolytic cell-side anode 111, water (H ２ O) to electrons (e － ) is taken away, and oxygen (O ２ ) and hydrogen ions (H ＋ 9 (d): In the aqueous chloride solution L10 (hypochlorous acid generation reaction) In the aqueous chloride solution L10 of the electrolytic bath 110, chlorine (Cl 2 ) generated by reaction formula (a) of FIG. ２ ) is the chloride aqueous solution L10 water (H ２ O), hydrolysis occurs, generating hydrochloric acid (HCl) and hypochlorous acid (HClO). Hydrochloric acid (HCl) ionizes in an aqueous solution, generating hydrogen ions (H ＋ ) and chloride ions (Cl － 9(e): When a voltage is applied to the anion exchange membrane 30 and a current flows through the membrane electrolysis section E20, the chloride aqueous solution L10 stored in the electrolytic cell 110 generates electrons (e － ) is lost. －In the chloride solution L10 that has lost its charge, a force that maintains electrical neutrality acts, and negatively charged chloride ions (Cl － ) is supplied from the magnesium chloride aqueous solution L20 stored in the supply tank 120 to the chloride aqueous solution L10 stored in the electrolytic tank 110 through the anion exchange membrane 130. In the chloride aqueous solution L10, the electrons (e － ) changes to chloride ions (Cl － ) Reaction formula (f) in Figure 9: Hypochlorous acid generation reaction (equilibrium reaction formula) Reaction formula (f) in Figure 9 shows the equilibrium reaction formula of the hypochlorous acid generation reaction. － When the equilibrium state shifts to the right side depending on the increase or decrease of Cl ２ +H ２ O) and the left side may be biased (HCl + HClO). － The current is controlled as described below so that the apparent increase or decrease in the amount of chloride ions is prevented. Equation (g) of FIG. 9: Equation of change in chloride ions during electrolysis. The amount of chloride ions (Cl) generated by reaction equation (a) of FIG. ２ ) changes into hydrochloric acid (HCl) and hypochlorous acid (HClO) according to reaction formula (d) in Figure 9. This can be expressed in one formula as formula (g) in Figure 9.

[0151] Figure 10 is a reaction formula including the ratio of the current flowing in the diaphragm-less electrolysis unit E10 to the current flowing in the diaphragm-containing electrolysis unit E20. Here, the ratio of the current flowing in the electrolytic cell-side anode 111 used for the chlorine generation reaction of reaction formula (a) in Figure 9 is represented by "x," and the ratio of the current used for the oxygen generation reaction of reaction formula (c) in Figure 9 is represented by "1-x." Furthermore, the ratio of the current flowing in the electrolytic cell-side anode 111 originating from the diaphragm-less electrolysis unit E10 is represented by "y," and the ratio of the current originating from the diaphragm-containing electrolysis unit E20 is represented by "1-y." Applying the above "x" and "y" to reaction formula (b) in Figure 9 + reaction formula (c) in Figure 9 + reaction formula (g) in Figure 9 and taking into account the change shown in (e) in Figure 9 results in reaction formula (a) in Figure 10.

[0152] When membrane-less electrolysis is performed in the membrane-less electrolysis unit E10, chloride ions (Cl －) is consumed and decreases, but in the space purification device 101 according to the second embodiment, chloride ions (Cl － ) is supplied.

[0153] Here, the amount of chloride ions (Cl) consumed by membraneless electrolysis is － ) from the magnesium chloride aqueous solution L20 stored in the supply tank 120 to the chloride aqueous solution L10 stored in the electrolytic tank 110, － ) is supplied to the electrolytic cell 110, and chloride ions (Cl － The conditions under which the apparent increase or decrease in the concentration of ClO is not observed are as follows: In this reaction, hypochlorous acid (HClO) evaporates as a gas, so it is not shown in the reaction formulas (b) to (g) shown in Figure 10. Reaction formula (b) in Figure 10: Cl － 10(a)-10(c) shows the condition under which there is no apparent increase or decrease. Conditional formula (c) of FIG. 10 shows the conditional formula for coefficients x and y obtained by modifying reaction formula (b) of FIG. 10. Reaction formula (d) of FIG. 10 shows the reaction formula when conditional formula (c) of FIG. 10 is substituted into reaction formula (a) of FIG. 10. Reaction formula (e) of FIG. 10 shows the reaction formula when reaction formula (d) of FIG. 10 is modified.

[0154] According to reaction formula (e) in Figure 10, for example, when two electrons flow into the diaphragm-less electrolysis unit E10, one hypochlorous acid (HClO) is generated. For example, when four electrons flow into the diaphragm-less electrolysis unit E10, one oxygen is generated. For example, when two electrons flow into the diaphragm-less electrolysis unit E10, one hydrogen is generated.

[0155] In addition, since the acid dissociation constant of hypochlorous acid (HClO) is approximately 7.5, it is necessary to maintain the pH of the chloride aqueous solution L1 so that it does not fluctuate. In reaction formula (e) of Figure 10, hydroxide ions and hydrogen ions, which are the factors that cause the pH to fluctuate, react to form water and disappear from the reaction formula. Therefore, the amount of chloride ions (Cl ) consumed by the membraneless electrolysis is － ) from the magnesium chloride aqueous solution L20 stored in the supply tank 120 to the chloride aqueous solution L10 stored in the electrolytic tank 110, －) is supplied, and Cl is added to the electrolytic cell 110. － 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.

[0156] As described above, when the number of electrons flowing in the membraneless electrolysis section E10 changes, that is, when the ratio of the current flowing in the membraneless electrolysis section E10 to the current flowing in the membraneless electrolysis section E20 changes, the amount of chloride ions supplied from the supply tank 120 to the electrolysis tank 110 changes. For example, when the ratio of the current used in membraneless electrolysis changes, the amount of chloride ions (Cl － ) is supplied to the electrolytic cell 110, and Cl － is greater than the current rate under the condition that there is no apparent increase or decrease (reaction formula (f) in FIG. 10 ), the Cl － The supply amount of Cl in the electrolytic cell 110 decreases. － decreases.

[0157] Cl in the electrolytic cell 110 － If the electrolysis without a diaphragm is continued in a state where the electrolysis efficiency is reduced, the Cl in the electrolytic cell 110 will gradually decrease. － increases, and Cl － reaches a level that does not appear to increase or decrease.

[0158] On the other hand, the amount of current used for membraneless electrolysis is such that chloride ions (Cl － ) is supplied to the electrolytic cell 110, and Cl － When the amount of current is greater than the condition under which the amount of current does not apparently increase or decrease (reaction formula (g) in FIG. 10 below), the Cl supplied from the supply tank 120 to the electrolytic tank 110 － The supply amount of Cl in the electrolytic cell 110 increases. － increases.

[0159] Chloride ions (Cl) in the electrolytic cell 110 － ) increases, the electrolysis efficiency of membrane-less electrolysis increases. If membrane-less electrolysis is continued in a state where the electrolysis efficiency has increased, the Cl in the electrolytic cell 110 gradually － decreases, and Cl － reaches a level that does not appear to increase or decrease.

[0160] In addition, Cl in the electrolytic cell 110 － When the amount of Cl in the electrolytic cell 110 increases, the equilibrium of the reaction formula (f) in FIG. 9 shifts to the left side, and the amount of chlorine generated increases. － By adjusting the current flowing through the membraneless electrolysis unit E10 and the current flowing through the membrane-containing electrolysis unit E20 so that the apparent increase or decrease in the current does not occur, hypochlorous acid can be produced while suppressing the generation of chlorine.

[0161] [Diaper Membrane Electrolysis Section E20] Fig. 11 is a list of reaction formulae that occur in the diaphragm electrolysis section E20. The reactions in the aqueous magnesium chloride solution L20 in the supply tank 120 will be described. The only electrode arranged in the supply tank 120 is the supply tank side cathode 121. When a predetermined voltage is applied to the diaphragm electrolysis section E20, a current flows, electrons move, and the chemical reaction shown in Fig. 11 occurs. Reaction formula (a) in Fig. 11: Supply tank side cathode 121 (hydrogen generation reaction) At the supply tank side cathode 121, water (H ２ O) is electron (e － ) and hydrogen (H ２ ) and hydroxide ions (OH － ) is generated. Hydrogen volatilizes as a gas, and hydroxide ions are used in reaction formula (c) of FIG. 11, which will be described later. (b) of FIG. 11: When a voltage is applied to the anion exchange membrane electrolysis section E20 and a current flows, chloride ions (Cl ) contained in the magnesium chloride aqueous solution L20 stored in the supply tank 120 are converted into anion ions. － ) passes through the anion exchange membrane 130 and is supplied to the chloride aqueous solution L10, and the magnesium chloride aqueous solution L20 passes through the supply tank side cathode 121 and receives electrons (e － In other words, in the magnesium chloride aqueous solution L20, the chloride ions (Cl － ) after the change, electrons (e － ) in the magnesium chloride aqueous solution L20. Reaction formula (c) in FIG. 11: Magnesium hydroxide precipitation reaction in the magnesium chloride aqueous solution L20. ２＋ ) and hydroxide ions (OH －) reacts with magnesium hydroxide (Mg(OH) ２ ) precipitate is formed. Magnesium hydroxide (Mg(OH) ２ ) is solubility product Ksp = 1.2 × 10 －１１ (mol / L) ３ For example, magnesium hydroxide is soluble in a weakly alkaline aqueous solution with a pH of 10, at only 1.2 × 10 －３ In the magnesium chloride aqueous solution L20 in the supply tank 120, hydroxide ions (OH － ) is used to generate magnesium hydroxide precipitate, thereby generating hydroxide ions (OH － ) can be suppressed from increasing in concentration, and an increase in pH of the magnesium chloride aqueous solution L20 can be suppressed.

[0162] Furthermore, when the magnesium chloride aqueous solution L20 is used, the pH of the magnesium hydroxide saturated aqueous solution produced after diaphragm electrolysis, in which magnesium hydroxide is saturated, is pH 10.36 as determined from the solubility product. Therefore, even after diaphragm electrolysis is performed over a long period of time, the pH of the magnesium chloride aqueous solution L20 can be maintained in a weakly alkaline state of up to 10.36 or less. In other words, when the magnesium chloride aqueous solution L20 is used, it is possible to prevent the aqueous solution from becoming strongly alkaline, with a pH of 11 or more. Therefore, it is possible to provide a space purification device 101 that is safer by preventing the aqueous solution stored in the supply tank 120 from becoming strongly alkaline after electrolysis.

[0163] Furthermore, for example, a contractor may install the space purification device 101 according to the second embodiment. After use of the space purification device 101, the space purification device 101 may be overturned or dropped when the contractor removes the installed space purification device, or when transporting the removed space purification device. When the magnesium chloride aqueous solution L20 is used here, the magnesium chloride aqueous solution L20 after the electrolysis reaction is a weakly alkaline magnesium hydroxide aqueous solution. Therefore, even if the magnesium chloride aqueous solution L20 leaks outside the space purification device 101 due to overturning or dropping, safety can be improved compared to space purification devices using sodium chloride aqueous solutions.

[0164] The above is a detailed description of the chemical reaction occurring in the membraneless electrolysis section E10 provided in the electrolytic cell 110 and the chemical reaction occurring in the membrane-containing electrolysis section E20 provided between the electrolytic cell 110 and the supply cell 120.

[0165] The current control unit 140 controls the chemical reaction by controlling the first current and the second current. More specifically, the first current and the second current are applied at a predetermined current ratio so that the chloride ion concentration in the chloride aqueous solution L10 is maintained at a predetermined concentration, thereby causing the chloride ions contained in the magnesium chloride aqueous solution L20 to permeate through the anion exchange membrane 130 and be supplied to the chloride aqueous solution L10.

[0166] Here, if a magnesium hydroxide precipitate is formed in the magnesium chloride aqueous solution L20 by diaphragm electrolysis, the magnesium chloride aqueous solution L20 becomes cloudy and its fluidity decreases. The inventors have discovered a problem in that the amount of chloride ions supplied from the magnesium chloride aqueous solution L20 to the chloride aqueous solution L10 may decrease as the fluidity of the magnesium chloride aqueous solution L20 decreases due to the formation of magnesium hydroxide precipitate. In the space purification device 101 according to the second embodiment, by controlling the current ratio between the first current and the second current using the current control unit 140 as described below, the chloride ion concentration of the chloride aqueous solution L10 can be maintained at a predetermined concentration even when the fluidity of the magnesium chloride aqueous solution L20 decreases due to the formation of magnesium hydroxide precipitate.

[0167] Hereinafter, the current control using the current control unit 140 will be described in detail with reference to FIG.

[0168] 12 is a block diagram showing the current control unit 140 according to the second embodiment. As shown in FIG. 12, the current control unit 140 includes an operating time acquisition unit 141 and a storage unit 142. The operating time acquisition unit 141 acquires the cumulative operating time of the space purification device 101. The storage unit 142 stores the cumulative operating time of the space purification device 101 acquired by the operating time acquisition unit 141 in association with the current ratio between the first current and the second current. The storage unit 142 may further store the cumulative operating time of the space purification device 101 in association with the amount of magnesium hydroxide precipitation.

[0169] The current control unit 140 controls the ratio of the first current to the second current within a predetermined total current range in accordance with the amount of magnesium hydroxide precipitation so that the chloride ion concentration of the chloride solution is maintained at a predetermined concentration. Here, the amount of magnesium hydroxide precipitation correlates with the operating time of the space purification device 101. More specifically, the longer the cumulative operating time of the space purification device 101, the greater the amount of magnesium hydroxide precipitation. That is, when the operating time of the space purification device 101 exceeds a predetermined cumulative operating time, it means that a predetermined amount of magnesium hydroxide precipitation has occurred. In other words, when the operating time of the space purification device 101 exceeds a predetermined cumulative operating time, the current control unit 140 controls the ratio of the first current to the second current within a predetermined total current range based on the memory unit 142 so that the chloride ion concentration of the chloride solution is maintained at a predetermined concentration.

[0170] When the current control unit 140 changes the current ratio between the first current and the second current, the current ratio of the first current is reduced and the current ratio of the second current is increased based on the memory unit 142, out of the predetermined total current amount.

[0171] Here, if the amount of current (mA) flowing through the electrolytic cell side anode 111 is Ia, the amount of current (mA) flowing through the electrolytic cell side cathode 112 is Ic, and the amount of current (mA) flowing through the supply cell side cathode 121 is Im, the following equation 1 holds true.

[0172] Ia = Ic + Im (Equation 1) The chloride ions (Cl) contained in the magnesium chloride aqueous solution L20 － ) permeates the anion exchange membrane 130 and moves into the chloride aqueous solution L10. In the initial state of the space purification device 101, chloride ions (Cl － The migration rate of chloride ions (Cl) is approximately 100%. － ) as well as hydroxide ions (OH － However, among all the anions that permeate the anion exchange membrane 130, chloride ions (Cl － ) permeates the anion exchange membrane 130 at a rate of approximately 100%, and hydroxide ions (OH － ) that permeate the anion exchange membrane 130 is 0.1% or less. － ) will not be taken into consideration in the following explanation of Equation 2 and subsequent formulas, and the initial chloride ions (Cl － In the initial state of the space purification device 101, the migration rate of chloride ions (Cl) that migrate due to membrane electrolysis is assumed to be approximately 100%. － ) is approximately 100%, the operation time of the space purification device 101 is t (seconds), and the following formula 2 holds.

[0173] Cl － Supply amount: Im×t (sec) / 9.65×10 ４ ... (Equation 2) As the operation time of the space purification device 101 increases, the chloride ions (Cl － ) decreases from approximately 100% to x% (0≦x<100). In this case, the following equation 3 holds:

[0174] Cl － Supply amount: (x / 100) x Im x t (sec) / 9.65 x 10 ４ ... (Formula 3) Chloride ions (Cl －) decreases, the amount of chloride ions supplied from the aqueous magnesium chloride solution L20 to the aqueous chloride solution L10 decreases. In order to maintain the chloride ion concentration of the aqueous chloride solution L10 at a predetermined concentration, it is necessary to maintain the amount of chloride ions supplied from the aqueous magnesium chloride solution L20 to the aqueous chloride solution L10 at a predetermined amount. Here, if Im is multiplied by y in order to maintain the amount of chloride ions supplied from the aqueous magnesium chloride solution L20 to the aqueous chloride solution L10 constant, the following equation 4 holds:

[0175] (Equation 2)=(Equation 3)×y (Equation 4) Transforming the above equation 4 results in the following equation 5.

[0176] x×y / 100=1 (Equation 5) The current control unit 140 changes the current ratio between the first current and the second current so that Equation 5 is satisfied.

[0177] Here, if the amount of current (mA) flowing through the electrolytic cell-side anode 111 after a predetermined operating time has elapsed is IaP, the amount of current (mA) flowing through the electrolytic cell-side cathode 112 is IcP, and the amount of current (mA) flowing through the supply cell-side cathode 121 is Imp, the following equations 6, 7, and 8 hold true.

[0178] IcP = Ic - (y - 1) Im (Equation 6) ImpP = Im x y (Equation 7) IaP = IcP + ImpP = Ic - (y - 1) Im + Im x y = Ic + Im (Equation 8) As shown in the above equations 6 to 8, chloride ions (Cl －When the migration rate of the chloride ions (IcP) decreases, the amount of chloride ions supplied from the magnesium chloride aqueous solution L20 to the chloride aqueous solution L10 must be increased to maintain a predetermined amount. Simultaneously with the increase in the amount of current ImP, the amount of current IaP flowing through the electrolytic cell-side anode 111 is maintained at a predetermined value. From Equation 8 above, in order to maintain the amount of current IaP flowing through the electrolytic cell-side anode 111 at a predetermined current amount, the amount of current IcP flowing through the electrolytic cell-side cathode 112 is reduced by the amount of increase in the amount of current ImP flowing through the supply cell-side cathode 121. This allows the amount of chloride ions consumed by the electrolytic cell-side anode 111 to be maintained at a predetermined value, while maintaining the chloride ion concentration of the chloride aqueous solution L10 at a predetermined concentration.

[0179] According to the above formula 8, the amount of current (mA) at the electrolytic cell-side anode 111 is IaP = Ic + Im, and the amount of current at the electrolytic cell-side anode 111 is not changed. In other words, the amount of current flowing through the electrolytic cell-side anode 111 is not changed from the predetermined total current amount. Therefore, even if the migration rate of chloride ions decreases, by reducing the current proportion of the first current and increasing the current proportion of the second current within the range of the predetermined total current amount, it is possible to maintain the amount of chloride ions consumed at the electrolytic cell-side anode 111 at a predetermined value and to maintain the chloride ion concentration of the aqueous chloride solution L10 at a predetermined concentration.

[0180] More specifically, for example, in the initial state of the space purification device 101, the first current is 90 mA, the second current is 10 mA, and the total current amount is 100 mA. Based on the cumulative operation time acquired by the operation time acquisition unit 141 and the memory unit 142, the current control unit 140 may control the first current to 80 mA, the second current to 20 mA, and the total current amount to 100 mA. That is, the current control unit 140 performs control such that the current proportion of the first current decreases and the current proportion of the second current increases as a predetermined cumulative operation time elapses.

[0181] As described above, the current control unit 140 controls the current ratio between the first current and the second current, so that a required amount of chloride ions can be supplied from the aqueous magnesium chloride solution L20 in the supply tank 120 to the aqueous chloride solution L10 in the electrolytic tank 110, and the chloride ion concentration in the aqueous chloride solution L10 can be maintained at a predetermined concentration.

[0182] As described above, the chloride ions consumed by the chloride aqueous solution L10 can be appropriately supplied from the magnesium chloride aqueous solution L20, thereby providing the space purification device 101 capable of stably generating a desired amount of hypochlorous acid gas. Therefore, the space purification device 101 can be provided that can stably generate a desired amount of hypochlorous acid gas for a long period of time, such as one year, without supplying an aqueous solution containing chloride ions from the outside.

[0183] Furthermore, even if the fluidity of the magnesium chloride aqueous solution L20 decreases due to precipitation of magnesium hydroxide, the amount of chloride ions supplied from the magnesium chloride aqueous solution L20 to the chloride aqueous solution L10 can be maintained at a predetermined amount. That is, the chloride ion concentration of the chloride aqueous solution L10 can be maintained at a predetermined concentration. Therefore, it is possible to provide the space purification device 101 that can stably generate a desired amount of hypochlorous acid gas for a long period of time, such as one year, without supplying an aqueous solution containing chloride ions from outside.

[0184] It is also possible to provide a plurality of current control units 140 and control the first current and the second current separately.

[0185] In addition, in FIG. 8 , the inlet 115 and the outlet 117 are arranged on the front left side (negative side of the y-axis and negative side of the x-axis) and the back right side (positive side of the y-axis and positive side of the x-axis) when the electrolytic cell 110 is viewed in plan, but the arrangement is not limited to this. For example, the positions of the inlet 115 and the outlet 117 may be reversed, the inlet 115 and the outlet 117 may be at the same position on the x-axis, or the inlet 115 and the outlet 117 may be at the same position on the y-axis. However, when the inlet 115 and the outlet 117 are arranged, it is preferable to arrange them so that they are at the farthest positions on the xy plane. By arranging them in this way, the time for the inflowing air and hypochlorous acid to mix in the mixing space 116 is longer, so that more hypochlorous acid can be contained in the mixed air.

[0186] Next, a case will be described in which plane P10 (the yz plane on the positive x-axis side) of the rectangular plate on the anion exchange membrane 130 side of the electrolytic cell-side anode plate 111 and plane P20 (the yz plane on the negative x-axis side) of the rectangular plate on the anion exchange membrane 130 side of the supply cell-side cathode plate 121 do not face each other. When the planes of each rectangle are arranged parallel to the xy plane, a non-uniform electric field may be generated between the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121. When a non-uniform electric field is generated between the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121, the current distribution between the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121 also becomes non-uniform.

[0187] When the current distribution between the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121 becomes uneven, regions of high and low current density are generated. The high current density regions are more susceptible to deterioration of the catalytic layer on the surfaces of the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121 (hereinafter also referred to as each electrode plate), while the low current density regions are less susceptible to deterioration of the catalytic layer on the surfaces of each electrode plate. That is, when an uneven electric field is generated between the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121, the current distribution becomes uneven, and regions of 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 unevenly. If the degree of deterioration of the catalytic layer on the surface of each electrode plate differs, repeated electrolysis may result in the simultaneous existence of regions on each electrode plate that can be used as an electrode and regions that have deteriorated to the point where they become unusable. When electrolysis is performed using electrode plates that include regions that cannot be used as electrodes, the electrolysis efficiency may be easily reduced.

[0188] In contrast, in the spatial purification device 101 according to the second embodiment, the planes P10 and P20 are arranged opposite each other with the anion exchange membrane 130 interposed therebetween. This arrangement allows a uniform electric field to be generated between the electrolytic cell-side anode plate 111 and the supply cell-side cathode plate 121, resulting in a uniform distribution of current between the two electrodes. Therefore, deterioration of the catalyst layer on the surface of each electrode plate occurs uniformly, and uneven deterioration of the catalyst layer on the surface of each electrode plate due to an uneven electric field can be suppressed even when electrolysis is performed repeatedly. This suppresses a decrease in electrolysis efficiency.

[0189] When membraneless electrolysis is performed in an electrolytic cell at room temperature and normal pressure, the electrolyte of the chloride aqueous solution L10 is not used in electrolysis, and oxygen and chlorine are mainly generated from the anode. The electrolyte does not react with hypochlorous acid to reduce the concentration of hypochlorous acid, and is electrically conductive and does not react with the electrodes, the electrolytic cell, or the anion exchange membrane. More specifically, in addition to the chloride aqueous solution L10 described above, the chloride aqueous solution may be, for example, a metal chloride aqueous solution, a hydroxide salt aqueous solution, an acid salt aqueous solution, a phosphate aqueous solution, or a combination thereof. The metal chloride aqueous solution may be, for example, a dilute calcium chloride aqueous solution or a dilute magnesium chloride aqueous solution. The hydroxide salt aqueous solution may be, for example, a dilute sodium hydroxide aqueous solution or a dilute potassium hydroxide aqueous solution of 0.4 wt % (0.1 mol / L) or less. The acid salt aqueous solution may be, for example, a dilute hydrochloric acid aqueous solution of 0.4 wt % (0.1 mol / L) or less. The phosphate aqueous solution may be, for example, a disodium hydrogen phosphate aqueous solution, a sodium dihydrogen phosphate aqueous solution, a dipotassium hydrogen phosphate aqueous solution, or a potassium dihydrogen phosphate aqueous solution.As a specific example of a combination of chloride aqueous solutions, the pH may be adjusted by combining a dilute sodium chloride aqueous solution with a dilute sodium hydroxide aqueous solution.

[0190] It should be noted that the present disclosure is not limited to the above-described second embodiment, and can be modified as appropriate within the scope of the present disclosure.

[0191] An outline of one aspect of the present disclosure is as follows.

[0192] (Item 11) An electrolytic cell for storing an aqueous chloride solution containing chloride ions; a supply cell for storing an aqueous magnesium chloride solution containing a higher concentration of chloride ions than the aqueous chloride solution and for supplying chloride ions to the aqueous chloride solution; an electrolytic cell-side anode and an electrolytic cell-side cathode provided in the electrolytic cell; a supply cell-side cathode provided in the supply cell; an anion exchange membrane provided to connect the electrolytic cell and the supply cell, the anion exchange membrane being permeable to anions based on a voltage applied between the electrolytic cell-side anode and the supply cell-side cathode; a membrane-less electrolysis section provided in the electrolytic cell, which generates hypochlorous acid by performing membrane-less electrolysis of the aqueous chloride solution by passing a first current between the electrolytic cell-side anode and the electrolytic cell-side cathode; and a membrane-with electrolysis section provided between the electrolytic cell and the supply cell, which performs membrane-with electrolysis via the anion exchange membrane by passing a second current between the electrolytic cell-side anode and the supply cell-side cathode. a current control unit that controls the current so that chloride ions contained in the magnesium chloride aqueous solution stored in the supply tank pass through the anion exchange membrane and are supplied to the chloride aqueous solution stored in the electrolytic tank, in order to replenish chloride ions contained in the chloride aqueous solution that have decreased as a result of performing the membrane-less electrolysis; wherein performing the membrane-with-diaphragm electrolysis causes magnesium ions contained in the magnesium chloride aqueous solution to react with hydroxide ions generated by the membrane-with-diaphragm electrolysis in the supply tank to form a magnesium hydroxide precipitate; and the current control unit controls the first current and the second current to flow at a predetermined current ratio, so that chloride ions contained in the magnesium chloride aqueous solution pass through the anion exchange membrane and are supplied to the chloride aqueous solution; and controls to change the current ratio of the first current and the second current within a predetermined range of total current amount according to the amount of magnesium hydroxide precipitate so that the chloride ion concentration of the chloride aqueous solution is maintained at a predetermined concentration.

[0193] (Item 12) The space purification device according to Item 11, wherein the current control unit includes a memory unit that stores an operating time of the space purification device and a current ratio between the first current and the second current in association with each other, and when a predetermined operating time has elapsed, the current control unit controls the current ratio between the first current and the second current based on the memory unit.

[0194] (Item 13) The space purification device according to Item 12, wherein the current control unit controls the change of the current ratio by the current control unit to decrease the current ratio of the first current and increase the current ratio of the second current based on the memory unit.

[0195] (Item 14) The electrolytic cell-side anode, the electrolytic cell-side cathode, and the supply cell-side cathode are electrolytic cell-side anode plates, electrolytic cell-side cathode plates, and supply cell-side cathode plates, each having a plate-like shape; the electrolytic cell-side anode plates and the electrolytic cell-side cathode plates are inserted into the electrolytic cell from the outside of the electrolytic cell, and the supply cell-side cathode plate is inserted into the supply cell from the outside of the supply cell; the electrolytic cell-side anode plates comprise an electrolytic cell-side anode plate immersed portion arranged on the inside of the electrolytic cell and an electrolytic cell-side anode plate protruding portion arranged on the outside of the electrolytic cell; the electrolytic cell-side cathode plates comprise an electrolytic cell-side cathode plate immersed portion arranged on the inside of the electrolytic cell and an electrolytic cell-side cathode plate protruding portion arranged on the outside of the electrolytic cell; and the supply cell-side cathode plate comprises a supply cell-side cathode plate immersed portion arranged on the inside of the supply cell and a supply cell-side cathode plate protruding portion arranged on the outside of the supply cell. Item 12. The space purification device according to Item 11, wherein the electrolytic cell-side anode plate immersed portion and the electrolytic cell-side cathode plate immersed portion are entirely immersed in the chloride aqueous solution, and the supply cell-side cathode plate immersed portion is entirely immersed in the magnesium chloride aqueous solution.

[0196] (Item 15) The space purification device according to Item 14, further comprising: a water level detection unit that detects a liquid level in the chloride aqueous solution; and a water supply unit that supplies water to the electrolytic cell so that the liquid level detected by the water level detection unit does not fall below upper ends of the electrolytic cell-side anode plate immersion portion and the electrolytic cell-side cathode plate immersion portion.

[0197] (Item 16) The space purification device according to Item 11, wherein the diaphragm-less electrolysis unit includes the electrolytic cell-side anode and the electrolytic cell-side cathode, and the diaphragm-containing electrolysis unit includes the electrolytic cell-side anode, the supply cell-side cathode, and the anion exchange membrane.

[0198] (Item 17) The space purification device according to Item 11, further comprising: a housing that houses the electrolytic cell and the supply cell; an inlet that is located within the housing above the liquid level of the aqueous chloride solution stored in the electrolytic cell and through which air flows in from an external space of the housing; a mixing space that mixes the volatilized hypochlorous acid with the air that has flowed in from the inlet; and an outlet through which the mixed air flows out to the external space.

[0199] 1. Space purification device 10. Electrolytic cell 11. Electrolytic cell-side anode 11a. Electrolytic cell-side anode plate immersed portion 11b. Electrolytic cell-side anode plate protrusion 12. Electrolytic cell-side cathode 12a. Electrolytic cell-side cathode plate immersed portion 12b. Electrolytic cell-side cathode plate protrusion 13. Wiring 14. Wiring 15. Inlet 16. Mixing space 17. Outlet 18. Water level detection unit 19. Water supply unit 20. Supply tank 21. Supply tank-side cathode 21a. Supply tank-side cathode plate immersed portion 21b. Supply tank-side cathode plate protrusion 22. Wiring 23. Discharge port 30. Anion exchange membrane 40. Current control unit 41. Voltage acquisition unit 42. Calculation unit 43. Estimation unit B. Housing L1. First aqueous solution L2. Second aqueous solution S1. Liquid level S2. Liquid level P1. Plane P2. Plane E1. Membraneless electrolysis unit E2 Electrolysis unit with diaphragm 101, space purification device 110, electrolytic cell 111, electrolytic cell-side anode 111a, electrolytic cell-side anode plate immersed portion 111b, electrolytic cell-side anode plate protrusion 112, electrolytic cell-side cathode 112a, electrolytic cell-side cathode plate immersed portion 112b, electrolytic cell-side cathode plate protrusion 113, wiring 114, wiring 115, inlet 116, mixing space 117, outlet 118, water level detection unit 119, water supply unit 120, supply tank 121, supply tank-side cathode 121a, supply tank-side cathode plate immersed portion 121b, supply tank-side cathode plate protrusion 122, wiring 123, outlet 130, cathode exchange membrane 140, current control unit 141, transformation time acquisition unit 142, memory unit B10, housing L10 Aqueous solution of chlorinated substances L20 Aqueous solution of chlorinated substances S10 Liquid level S20 Liquid level P10 Flat surface P20 Flat surface E10 Electrolysis section without diaphragm E20 Electrolysis section with diaphragm

Claims

1. An electrolytic cell for storing a first aqueous solution containing chloride ions; and a supply cell for storing a second aqueous solution containing a higher concentration of chloride ions than the first aqueous solution and supplying chloride ions to the first aqueous solution; a housing for housing the electrolytic cell and the supply cell; an inlet located within the housing above the liquid level of the first aqueous solution stored in the electrolytic cell, through which air flows in from the external space of the housing; an electrolytic cell-side anode and an electrolytic cell-side cathode provided in the electrolytic cell; a supply cell-side cathode provided in the supply cell; an anion exchange membrane provided to connect the electrolytic cell and the supply cell, which allows anions to pass through based on a voltage applied between the electrolytic cell-side anode and the supply cell-side cathode; and a membrane-less electrolysis unit provided in the electrolytic cell for electrolyzing the first aqueous solution without a membrane to generate hypochlorous acid by passing a first current between the electrolytic cell-side anode and the electrolytic cell-side cathode. a diaphragm-equipped electrolysis section provided between the electrolytic cell and the supply cell, the diaphragm-equipped electrolysis performing membrane-equipped electrolysis via the anion exchange membrane by passing a second current between the electrolytic cell-side anode and the supply cell-side cathode; a mixing space for mixing the volatilized hypochlorous acid with the air flowing in from the inlet; and an outlet through which the mixed air flows out to the external space, wherein the second aqueous solution is a metal chloride aqueous solution containing metal ions and the chloride ions, and by performing the diaphragm-equipped electrolysis, the chloride ions contained in the second aqueous solution stored in the supply cell are supplied to the first aqueous solution stored in the electrolytic cell through the anion exchange membrane so as to replenish the chloride ions contained in the first aqueous solution reduced by the diaphragm-less electrolysis, and in the supply cell, the metal ions contained in the second aqueous solution and hydroxide ions generated by the diaphragm-equipped electrolysis react with each other to form a precipitate of metal hydroxide.

2. The spatial purification device according to claim 1, wherein the second aqueous solution is an aqueous magnesium chloride solution.

3. The spatial purification device according to claim 1, further comprising a current control unit that controls a second current so that chloride ions contained in the second aqueous solution stored in the supply tank are passed through the anion exchange membrane and supplied to the first aqueous solution stored in the electrolytic tank in order to replenish chloride ions contained in the first aqueous solution reduced by the membrane-less electrolysis, and the current control unit controls the first current and the second current to flow at a predetermined ratio so as to maintain the chloride ion concentration of the first aqueous solution at a predetermined concentration.

4. The space purification device according to claim 3, wherein the current control unit comprises: a voltage acquisition unit that acquires a voltage between the electrolytic cell side anode and the electrolytic 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; and an estimation unit that estimates the concentration of the first aqueous solution based on the conductivity calculated by the calculation unit; and the current control unit simultaneously flows the first current and the second current, and, when a chloride ion concentration of the first aqueous solution is lower than the predetermined concentration, controls to change the current ratio of the first current and the second current so as to increase the amount of chloride ions that permeate the anion exchange membrane from the second aqueous solution and are supplied to the first aqueous solution, when the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration.

5. The spatial purification device according to claim 4, wherein the current control unit controls so as not to change the current ratio between the first current and the second current when the chloride ion concentration of the first aqueous solution is the specified concentration.

6. The space purification device according to claim 3, wherein the current control unit comprises: a voltage acquisition unit that acquires a voltage between the electrolytic cell side anode and the electrolytic 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; and an estimation unit that estimates the concentration of the first aqueous solution based on the conductivity calculated by the calculation unit, wherein the current control unit controls the second current while flowing the first current at a predetermined value, and wherein the control of the second current is performed by: when the chloride ion concentration of the first aqueous solution is lower than the predetermined concentration, the second current is flowed so as to increase the amount of chloride ions that permeate the anion exchange membrane from the second aqueous solution and are supplied to the first aqueous solution, and when the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, the second current is stopped so as to stop the supply of chloride ions from the second aqueous solution to the first aqueous solution.

7. The space purification device according to claim 3, wherein the current control unit comprises: a voltage acquisition unit that acquires a voltage between the electrolytic cell side anode and the electrolytic 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; and an estimation unit that estimates a concentration of the first aqueous solution based on the conductivity calculated by the calculation unit, and wherein the current control unit, when a chloride ion concentration of the first aqueous solution is lower than the predetermined concentration, controls to stop the first current and simultaneously flow the second current so that an amount of chloride ions that permeate through the anion exchange membrane from the second aqueous solution and are supplied to the first aqueous solution increases, and when a chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, controls to stop the second current and simultaneously flow the first current so that the supply of chloride ions from the second aqueous solution to the first aqueous solution is stopped.

8. The electrolytic cell side anode, the electrolytic cell side cathode, and the supply cell side cathode are, respectively, an electrolytic cell side anode plate, an electrolytic cell side cathode plate, and a supply cell side cathode plate each having a plate-like shape, the electrolytic cell side anode plate and the electrolytic cell side cathode plate being inserted into the electrolytic cell from the outside of the electrolytic cell, and the supply cell side cathode plate being inserted into the supply cell from the outside of the supply cell, the electrolytic cell side anode plate comprises an electrolytic cell side anode plate immersed portion arranged on the inside of the electrolytic cell and an electrolytic cell side anode plate protruding portion arranged on the outside of the electrolytic cell, the electrolytic cell side cathode plate comprises an electrolytic cell side cathode plate immersed portion arranged on the inside of the electrolytic cell and an electrolytic cell side cathode plate protruding portion arranged on the outside of the electrolytic cell, and the supply cell side cathode plate comprises a supply cell side cathode plate immersed portion arranged on the inside of the supply cell and a supply cell side cathode plate protruding portion arranged on the outside of the supply cell, The space purification device according to claim 1 , wherein the electrolytic cell side anode plate immersed portion and the electrolytic cell side cathode plate immersed portion are entirely immersed in the first aqueous solution, and the supply cell side cathode plate immersed portion is entirely immersed in the second aqueous solution.

9. The spatial purification device as described in claim 8, further comprising: a water level detection unit that detects the position of the liquid level in the first aqueous solution; and a water supply unit that supplies water to the electrolytic cell so that the position of the liquid level detected by the water level detection unit does not fall below the upper ends of the electrolytic cell side anode plate immersion portion and the electrolytic cell side cathode plate immersion portion.

10. The spatial purification device according to claim 1, wherein the non-diaphragm electrolysis section comprises the electrolytic cell side anode and the electrolytic cell side cathode, and the diaphragm electrolysis section comprises the electrolytic cell side anode, the supply cell side cathode, and the anion exchange membrane.

11. An electrolytic cell for storing an aqueous chloride solution containing chloride ions; a supply cell for storing an aqueous magnesium chloride solution containing a higher concentration of chloride ions than the aqueous chloride solution and supplying chloride ions to the aqueous chloride solution; an electrolytic cell side anode and an electrolytic cell side cathode provided in the electrolytic cell; a supply cell side cathode provided in the supply cell; an anion exchange membrane provided to connect the electrolytic cell and the supply cell, and allowing anions to pass therethrough based on a voltage applied between the electrolytic cell side anode and the supply cell side cathode; a membrane-less electrolysis section provided in the electrolytic cell for generating hypochlorous acid by performing membrane-less electrolysis of the aqueous chloride solution by passing a first current between the electrolytic cell side anode and the electrolytic cell side cathode; and a membrane-containing electrolysis section provided between the electrolytic cell and the supply cell, and performing membrane-containing electrolysis via the anion exchange membrane by passing a second current between the electrolytic cell side anode and the supply cell side cathode. a current control unit that controls a current so that chloride ions contained in the magnesium chloride aqueous solution stored in the supply tank are supplied to the chloride aqueous solution stored in the electrolytic cell through the anion exchange membrane in order to compensate for chloride ions contained in the chloride aqueous solution reduced by performing the membrane-less electrolysis; by performing the membrane-with-diaphragm electrolysis, magnesium ions contained in the magnesium chloride aqueous solution react with hydroxide ions generated by the membrane-with-diaphragm electrolysis in the supply tank to form a precipitate of magnesium hydroxide, and the current control unit controls the first current and the second current to flow at a predetermined current ratio so that chloride ions contained in the magnesium chloride aqueous solution stored in the supply tank are supplied to the chloride aqueous solution stored in the electrolytic cell through the anion exchange membrane, and controls to change the current ratio of the first current and the second current within a predetermined range of total current amount in accordance with an amount of precipitate of magnesium hydroxide so that a chloride ion concentration of the chloride aqueous solution is maintained at a predetermined concentration.

12. The space purification device according to claim 11, wherein the current control unit includes a memory unit that stores an operating time of the space purification device and a current ratio between the first current and the second current in association with each other, and when a predetermined operating time has elapsed, controls so as to change the current ratio between the first current and the second current based on the memory unit.

13. The spatial purification device according to claim 12, wherein the current control unit controls, in changing the current ratio, the current ratio of the first current to be decreased and the current ratio of the second current to be increased based on the memory unit.

14. The electrolytic cell side anode, the electrolytic cell side cathode, and the supply cell side cathode are, respectively, an electrolytic cell side anode plate, an electrolytic cell side cathode plate, and a supply cell side cathode plate each having a plate-like shape, the electrolytic cell side anode plate and the electrolytic cell side cathode plate being inserted into the electrolytic cell from the outside of the electrolytic cell, and the supply cell side cathode plate being inserted into the supply cell from the outside of the supply cell, the electrolytic cell side anode plate comprises an electrolytic cell side anode plate immersed portion arranged on the inside of the electrolytic cell and an electrolytic cell side anode plate protruding portion arranged on the outside of the electrolytic cell, the electrolytic cell side cathode plate comprises an electrolytic cell side cathode plate immersed portion arranged on the inside of the electrolytic cell and an electrolytic cell side cathode plate protruding portion arranged on the outside of the electrolytic cell, and the supply cell side cathode plate comprises a supply cell side cathode plate immersed portion arranged on the inside of the supply cell and a supply cell side cathode plate protruding portion arranged on the outside of the supply cell, The space purification device according to claim 11 , wherein the electrolytic cell side anode plate immersed portion and the electrolytic cell side cathode plate immersed portion are entirely immersed in the chloride aqueous solution, and the supply cell side cathode plate immersed portion is entirely immersed in the magnesium chloride aqueous solution.

15. The spatial purification device according to claim 14, further comprising: a water level detection unit that detects the position of the liquid level in the aqueous chloride solution; and a water supply unit that supplies water to the electrolytic cell so that the position of the liquid level detected by the water level detection unit does not fall below the upper ends of the electrolytic cell side anode plate immersion portion and the electrolytic cell side cathode plate immersion portion.

16. The spatial purification device according to claim 11, wherein the non-diaphragm electrolysis section comprises the electrolytic cell side anode and the electrolytic cell side cathode, and the diaphragm electrolysis section comprises the electrolytic cell side anode, the supply cell side cathode, and the anion exchange membrane.

17. The space purification device described in claim 11, further comprising: a housing for housing the electrolytic cell and the supply cell; an inlet located within the housing above the liquid level of the aqueous chloride solution stored in the electrolytic cell, through which air flows in from an external space of the housing; a mixing space for mixing the volatilized hypochlorous acid with the air that has flowed in from the inlet; and an outlet through which the mixed air flows out to the external space.

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