Space purification device

Abstract

To provide a space purification device that suppresses degradation of an electrode and enables stable generation of a desired amount of hypochlorous acid gas for a long time without external supply of chloride.SOLUTION: A space purification device 1 comprises a current control unit 50 that, by controlling a second electrical current so as to compensate for chloride ions contained in a first aqueous solution L1 that are reduced by membraneless electrolysis, supplies chloride ions contained in a second aqueous solution L2 to the first aqueous solution L1 through an anion exchange membrane 40. The current control unit 50 controls such that current values flowing to a plurality of electrolytic cell anodes 12, 13, 14 in membraneless electrolysis are equal to each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

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

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

[0004] When a conventional space purification device is miniaturized, the tank for storing the aqueous solution used for electrolysis also becomes smaller. Miniaturizing the tank reduces the amount of aqueous solution that can be stored compared to conventional space purification devices. Therefore, when electrolysis is repeatedly performed in a miniaturized space purification device, the chloride ion concentration in the aqueous solution tends to decrease, resulting in an unstable amount of hypochlorous acid generated. Furthermore, miniaturizing the tank also requires smaller electrodes compared to conventional space purification devices. When attempting to achieve the same performance as conventional space purification devices, i.e., to generate the same amount of hypochlorous acid as conventional space purification devices, the current density at the electrodes during electrolysis increases, causing the electrode catalyst layer on the electrode surface to dissolve, resulting in electrode deterioration and resulting in an unstable amount of hypochlorous acid generated.

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

[0006] The spatial purification device according to the present invention comprises 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, an electrolytic cell-side anode group comprising a plurality of electrolytic cell-side anodes and an electrolytic cell-side cathode provided in the electrolytic cell, a supply cell-side cathode provided in the supply cell, an anion exchange membrane connecting the electrolytic cell and the supply cell to allow anions to pass therethrough based on a voltage applied between the electrolytic cell-side anode group and the supply cell-side cathode, and an anion exchange membrane provided in the electrolytic cell and connecting the electrolytic cell-side anode group and the electrolytic cell-side cathode. The electrolysis device comprises: a membrane-less electrolysis unit that generates hypochlorous acid by performing membrane-less electrolysis of a first aqueous solution by passing a first current between the electrolytic cell-side anode and the cell-side cathode; a membrane-with-diaphragm electrolysis unit that is provided between the electrolytic cell and the supply cell and that performs membrane-with-diaphragm 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 second current so as to replenish chloride ions contained in the second aqueous solution that have been reduced by the diaphragm-less electrolysis, thereby causing chloride ions contained in the second aqueous solution to pass through the anion exchange membrane and be supplied to the first aqueous solution. The current control unit controls the current values ​​that flow through the multiple electrolytic cell-side anodes during membrane-less electrolysis to be equal to each other. [Effects of the Invention]

[0007] The present invention suppresses electrode deterioration and allows chloride to be supplied from the outside for a long period of time. This makes it possible to provide a space purification device that can stably generate a desired amount of hypochlorous acid gas without any trouble. [Brief explanation of the drawings]

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

[0009] Specific embodiments of the present invention will be described in detail below with reference to the drawings. The right-handed xyz coordinate system shown in the figures 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 figures.

[0010] <First Embodiment> 1 is a perspective view showing an outline of a space purifying device 1 according to Embodiment 1. The space purifying device 1 performs electrolysis on a first aqueous solution L1 containing chloride ions in an electrolytic cell 10, which will be described later, to generate and volatilize hypochlorous acid. The space purifying device 1 removes bacteria, fungi, viruses, odors, and the like contained in the air in the external space of the space purifying device 1 by causing the volatilized hypochlorous acid to flow into the external space of a housing B constituting the space purifying device 1.

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

[0012] The spatial purification device 1 includes a housing B, an electrolytic cell 10, a supply cell 30, an anion exchange membrane 40, and a current control unit 50.

[0013] The housing B houses the electrolytic cell 10, the supply cell 30, the anion exchange membrane 40, and the current control unit 50. 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.

[0014] The electrolytic cell 10 is a cell for storing a first aqueous solution L1 containing chloride ions. The electrolytic cell 10 has, for example, a box-like shape. FIG. 1 shows the first aqueous solution L1 stored in the electrolytic cell 10. The first aqueous solution L1 is, for example, an aqueous solution in which an electrically conductive electrolyte is dissolved, and more specifically, a dilute chloride aqueous solution having a predetermined chloride ion concentration. More specifically, the first aqueous solution L1 is, for example, a sodium chloride aqueous solution or a dilute potassium chloride aqueous solution.

[0015] The "predetermined chloride ion concentration" of the first aqueous solution L1 includes both a chloride ion concentration having a predetermined range of values ​​and a chloride ion concentration having a predetermined value. The chloride ion concentration of the first aqueous solution L1 may be, for example, 1 g / L to 50 g / L, or may be 10 g / L. In other words, the mass percent concentration of the dilute sodium chloride aqueous solution or the dilute potassium chloride aqueous solution may be, for example, 0.1% to 5%, or may be 5%. By setting the predetermined chloride ion concentration within this range or numerical value, it is possible to generate hypochlorous acid necessary for space purification while suppressing the generation of chlorine that may be generated at the same time.

[0016] The supply tank 30 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 30 permeate through the anion exchange membrane 40 and are supplied to the first aqueous solution L1 in the electrolytic tank 10.

[0017] The supply tank 30 is a tank for storing a second aqueous solution L2 containing chloride ions and supplying the chloride ions to the first aqueous solution L1. FIG. 1 shows the second aqueous solution L2 stored in the supply tank 30. The chloride ion concentration of the second aqueous solution L2 is higher than that of the first aqueous solution L1. To ensure safety in the event of leakage, the solute of the second aqueous solution L2 is preferably a substance classified under the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) as being as safe as sodium chloride. Specifically, the second aqueous solution L2 is a metal chloride aqueous solution containing metal ions and chloride ions. When the second aqueous solution L2 is subjected to membrane electrolysis (described later), 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%.

[0018] Assuming continuous use for eight hours a day for one year, the respective volumes of the electrolytic cell 10 and the supply cell 30 are preferably set so that the volume of the supply cell 30 is at least about 12 times the volume of the electrolytic cell 10. By setting such a volume ratio, the supply cell 30 can store the second aqueous solution L2 containing a sufficient amount of chloride ions required to be supplied to the first aqueous solution L1 of the electrolytic cell 10. Therefore, chloride ions can be stably supplied from the second aqueous solution L2 stored in the supply cell 30 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.

[0019] The anion exchange membrane 40 is a membranous member that connects the electrolytic cell 10 and the supply cell 30 in a manner that allows anions to pass therethrough, based on a voltage applied between the electrolytic cell 10 and the supply cell 30. More specifically, when a voltage is applied between the electrolytic cell-side anode 13 and the supply cell-side cathode 31 that constitute the electrolytic cell-side anode group 11 described below, membrane-operated electrolysis occurs via the anion exchange membrane 40. By membrane-operated electrolysis using the electrolytic cell-side anode 13 and the supply cell-side cathode 31, chloride ions contained in the second aqueous solution L2 permeate the anion exchange membrane 40 and are supplied to the first aqueous solution L1 (in the negative direction of the x-axis, indicated by a thick black arrow).

[0020] The anion exchange membrane 40 in this embodiment is not a type of anion exchange membrane that allows anions to permeate due to osmotic pressure without using electricity. Furthermore, magnesium ions, which are cations, do not permeate the anion exchange membrane 40. More specifically, when chloride ions contained in the second aqueous solution L2 are permeated through the anion exchange membrane 40 and supplied to the first aqueous solution L1 by membrane electrolysis using the electrolytic cell-side anode 13 and the supply cell-side cathode 31, magnesium ions, which are cations, do not permeate the anion exchange membrane 40. The anion exchange membrane 40 may be, for example, a hydrocarbon-based anion exchange membrane, and may include membranes that have monovalent anion-selective permeability, alkali resistance, and high-temperature resistance.

[0021] The anion exchange membrane 40 is disposed between the electrolytic cell 10 and the feed cell 30. For example, The surface of the decomposition tank 10 facing the supply tank 30 (the yz plane on the positive side of the x-axis) and the surface of the supply tank 30 facing the electrolytic tank 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 tank 10 and the supply tank 30 are each formed by a frame-shaped member, the anion exchange membrane 40 may be disposed so as to be fitted into the frame-shaped member.

[0022] Here, the only anode used in membrane-type electrolysis among the electrolytic cell-side anode group 11 is the electrolytic cell-side anode 13, and therefore the width of the anion exchange membrane 40 along the y-axis direction only needs to be equal to or less than the widths of the electrolytic cell-side anode 13 and the supply cell-side cathode 31 along the y-axis direction. For example, if the anion exchange membrane 40 is rectangular, the width of the anion exchange membrane 40 along the y-axis direction may be equal to or less than the widths of the electrolytic cell-side anode 13 and the supply cell-side cathode 31 along the y-axis direction, and may be determined so that the central axes coincide. Here, the "central axis" refers to an axis along the x-axis direction in plan view (see FIG. 2 ), passing through the center point of the widths of the electrolytic cell-side anode 13, the anion exchange membrane 40, and the supply cell-side cathode 31 along the y-axis direction on the negative x-axis side and the center point of the widths of the anion exchange membrane 40 and the supply cell-side cathode 31 along the y-axis direction on the positive x-axis side.

[0023] The current control unit 50 controls the current used in the diaphragmless electrolysis and the diaphragm-containing electrolysis. More specifically, the current control unit 50 controls the current used in the diaphragm-free electrolysis performed using a pair of electrolytic cell-side anode group 11 and electrolytic cell-side cathode 15 arranged in the electrolytic cell 10.

[0024] Furthermore, the current control unit 50 controls the current used in membrane electrolysis, which is performed via an anion exchange membrane 40 using a pair of an electrolytic cell-side anode 13 and a supply cell-side cathode 31, across the electrolytic cell 10 and the supply cell 30. The electrolytic cell-side anode 13 is used for both membraneless electrolysis and membrane-containing electrolysis. The space purification device 1 according to this embodiment includes multiple anodes and two cathodes. Because the supply cell 30 includes only a cathode, chlorine is not generated within the supply cell 30 by a chemical reaction, which will be described later.

[0025] The details of each component will be described in more detail below. As shown in FIG. 1, the electrolytic cell 10 includes an electrolytic cell-side anode group 11 , an electrolytic cell-side cathode 15 , wires 16 , 17 , 18 , 19 , an inlet 20 , a mixing space 21 , and an outlet 22 .

[0026] The electrolytic cell-side anode group 11 is composed of a plurality of electrolytic cell-side anodes 12, 13, 14. Although three electrolytic cell-side anodes 12, 13, 14 are shown as an example in Fig. 1, the number of electrolytic cell-side anodes may be at least two or more, and preferably two to four.

[0027] The electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15 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 group 11 and the electrolytic cell-side cathode 15. In other words, the electrolysis of the first aqueous solution L1 performed using the pair of the electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15 is membrane-less electrolysis. Hypochlorous acid, which is used for space purification, is produced by the membrane-less electrolysis of the first aqueous solution L1 performed using the pair of the electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15.

[0028] The electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15 each have a plate-like shape. That is, the multiple electrolytic cell-side anodes 12, 13, 14 constituting the electrolytic cell-side anode group 11 are multiple electrolytic cell-side anode plates 12, 13, 14 having a plate-like shape. Also, the electrolytic cell-side cathode 15 is an electrolytic cell-side cathode plate 15 having a plate-like shape. Plate-like shapes include rectangular and oblong shapes.

[0029] As an example, a case will be described in which the plate shapes of the electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15 are rectangular. The multiple electrolytic cell-side anodes 12, 13, 14 that make up the electrolytic cell-side anode group 11 are arranged in a row with the shorter side of the rectangle aligned horizontally (y-axis direction). In other words, from the negative side of the y-axis, the electrolytic cell-side anode 12, the electrolytic cell-side anode 13, the electrolytic cell-side anode 15, 4 are arranged in the horizontal direction (y-axis direction).

[0030] The electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15 are arranged such that the longitudinal direction of the rectangle is along the vertical direction (z-axis direction). The electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15 are arranged such that the planes (yz planes) of their respective rectangles face each other with a predetermined distance between them. The predetermined distance is a distance appropriate for electrolysis performed using the pair of electrolytic cell-side anode group 11 and electrolytic cell-side cathode 15.

[0031] The electrolytic cell-side anode plates 12, 13, 14 constituting the electrolytic cell-side anode group 11 each have an electrolytic cell-side anode plate immersed portion 12a, 13a, 14a and an electrolytic cell-side anode plate protruding portion 12b, 13b, 14b. Similarly, the electrolytic cell-side cathode 15 has an electrolytic cell-side cathode plate immersed portion 15a and an electrolytic cell-side cathode plate protruding portion 15b.

[0032] The electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15 are inserted from the outside of the electrolytic cell 10 toward the inside. In FIG. 1 , as an example, the electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15 are inserted vertically (in the z-axis direction) from the bottom side of the electrolytic cell 10 (the xy plane side on the z-axis negative side). The electrolytic cell-side anode plate immersed portions 12a, 13a, 14a and the electrolytic cell-side cathode plate immersed portion 15a 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 portions 12a, 13a, 14a and the electrolytic cell-side cathode plate immersed portion 15a 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 12a, 13a, 14a and the electrolytic cell side cathode plate immersed portion 15a.

[0033] The electrolytic cell-side anode plate protrusions 12b, 13b, and 14b and the electrolytic cell-side cathode plate protrusion 15b are disposed on the exterior side of the electrolytic cell 10. Wires 16, 17, 18, and 19 are lines through which current flows. The electrolytic cell-side anode plate protrusion 12b is electrically connected to a current control unit 50 via wire 16, the electrolytic cell-side anode plate protrusion 13b via wire 17, the electrolytic cell-side anode plate protrusion 14b via wire 18, and the electrolytic cell-side cathode plate protrusion 15b via wire 19.

[0034] The electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15 may be electrodes using, for example, platinum, ruthenium, iridium oxide, or the like as an electrode catalyst, and more specifically, platinum-iridium-titanium electrodes, platinum electrodes, ruthenium-titanium electrodes, iridium-titanium oxide electrodes, or the like may be used.

[0035] The inlet 20 is an opening through which air from the space outside the casing B flows in. That is, the inlet 20 is an opening through which air from the space outside the space purification device 1 flows in. In FIG. 1, the inlet 20 is provided on the top surface (xy plane on the positive side of the z-axis) of the electrolytic cell 10 as an example, but it may be located above the liquid level S1 of the first aqueous solution L1. The shape of the inlet 20 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 inlet 20 may be a hole-like opening provided in part of the top surface of the electrolytic cell 10. Alternatively, the inlet 20 and the top surface (the surface on the positive side of the z-axis) of the casing B may be integrally formed.

[0036] The mixing space 21 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 21 is a space in which hypochlorous acid produced by membrane-less electrolysis of the first aqueous solution L1, which is carried out using a pair of electrolytic cell-side anode group 11 and electrolytic cell-side cathode 15, is mixed with air from the external space that flows in from the inlet 20. The hypochlorous acid produced 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 The hypochlorous acid dissolved in the first aqueous solution L1 is contained in the air flowing in from the inlet 20 and flows out to the external space from the outlet 22 described later. The hypochlorous acid dissolved in the first aqueous solution L1 comes into gas-liquid contact with the air flowing in from the inlet 20, and flows out to the external space from the outlet 22 described later.

[0037] The outlet 22 is an opening through which mixed air, which is a mixture of air flowing in from the inlet 20 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 22 is an opening through which the mixed air flows out to the space outside the space purification device 1. In FIG. 1, the outlet 22 is provided on the top surface (xy plane on the positive side of the z-axis) of the electrolytic cell 10 as an example, similar to the inlet 20, but it need only be located above the liquid level of the first aqueous solution L1. The shape of the outlet 22 is similar to that of the inlet 20 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 22 may be a hole-like opening provided in a part of the top surface of the electrolytic cell 10. Alternatively, the outlet 22 and the top surface (the surface on the positive side of the z-axis) of the casing B may be integrally formed.

[0038] The inlet 20 and the outlet 22 may be provided with a lid (not shown) that can be opened and closed or that can be attached and detached. The lid may be configured to be closed when the space purification device 1 is transported, moved, or installed, and to be opened or detached when the space purification device 1 is used. Furthermore, although the inlet 20 and the outlet 22 have been described as having separate structures, the inlet 20 and the outlet 22 may each serve as both an inlet and an outlet depending on the direction of the wind flowing into the space purification device 1.

[0039] The air containing hypochlorous acid that flows out from the outlet 22 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.

[0040] The supply tank 30 includes a supply tank-side cathode 31, wiring 32, and an outlet 33. The supply tank-side cathode 31 is an electrode used in conjunction with the electrolytic cell-side anode 13 constituting the electrolytic cell-side anode group 11 for electrolysis of the second aqueous solution L2. As shown in FIG. 1 , an anion-exchange membrane 40 is disposed between the electrolytic cell-side anode 13 and the supply tank-side cathode 31 constituting the electrolytic cell-side anode group 11. That is, the electrolysis of the second aqueous solution L2 performed using the paired electrolytic cell-side anode 13 and supply tank-side cathode 31 is membrane-less electrolysis. That is, the electrolytic cell-side anode 13 is used for both membrane-less electrolysis and membrane-less electrolysis. Chloride ions are supplied from the second aqueous solution L2 to the first aqueous solution L1 by the membrane-less electrolysis of the second aqueous solution L2 performed using the paired electrolytic cell-side anode 13 and supply tank-side cathode 31.

[0041] The supply tank side cathode 31 is a supply tank side cathode plate 31 having a plate shape. The plate shape includes a rectangular shape and an oblong shape.

[0042] As an example, a case will be described in which the supply tank side cathode plate 31 is also rectangular in plate shape, similar to the multiple electrolytic tank side anode plates 12, 13, and 14 that make up the electrolytic tank side anode group 11. As shown in Fig. 1, the supply tank side cathode plate 31 is arranged so that the shorter side of the rectangle is aligned along the vertical direction (z-axis direction). Furthermore, the supply tank side cathode plate 31 is arranged so that the longer side of the rectangle is aligned along the horizontal direction (y-axis direction).

[0043] The electrolytic cell-side anode plates 13 and the supply cell-side cathode plates 31 that make up the electrolytic cell-side anode group 11 are each in close proximity to the anion exchange membrane 40. In this specification, "in close proximity" includes both a state in which the electrolytic cell-side anode plates 13 and the supply cell-side cathode plates 31 are close to the anion exchange membrane 40 with a predetermined gap between them, and a state in which the electrolytic cell-side anode plates 13 and the supply cell-side cathode plates 31 are in contact with the anion exchange membrane 40.

[0044] The plane of the rectangular plate on the anion exchange membrane 40 side of the electrolytic cell-side anode plate 13 (the yz plane on the positive x-axis side) is defined as plane P1. The plane of the rectangular plate on the anion exchange membrane 40 side of the supply cell-side cathode 31 (the yz plane on the negative x-axis side) is defined as plane P2. Planes P1 and P2 are arranged opposite each other with the anion exchange membrane 40 interposed therebetween. This arrangement allows a uniform electric field to be generated between the electrolytic cell-side anode plate 13 and the supply cell-side cathode 31.

[0045] The electrolytic cell-side anode group 11 is disposed between the electrolytic cell-side cathode 15 and the anion exchange membrane 40. This arrangement makes it possible to maintain small the potential difference between the electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15, and the potential difference between the electrolytic cell-side anode plate 13 constituting the electrolytic cell-side anode group 11 and the supply cell-side cathode 31.

[0046] The supply tank side cathode plate 31 includes a supply tank side cathode plate immersed portion 31a and a supply tank side cathode plate protruding portion 31b. The supply tank side cathode 31 is inserted from the outside of the electrolytic cell 10 toward the inside. In FIG. 1 , as an example, the supply tank side cathode 31 is inserted vertically (in the z-axis direction) from the bottom side of the electrolytic cell 10 (the xy plane side on the z-axis negative side). The supply tank side cathode plate immersed portion 31a inserted into the supply tank 30 is positioned inside the supply tank 30 and is entirely immersed in the second aqueous solution L2. In other words, the second aqueous solution L2 is stored in the supply tank 30 such that the entire supply tank side cathode plate immersed portion 31a is immersed. That is, the second aqueous solution L2 is stored in the supply tank 30 such that the liquid level S2 of the second aqueous solution L2 exceeds the upper end (the end on the z-axis positive side) of the supply tank side cathode plate immersed portion 31a.

[0047] 1, the supply tank-side cathode plate protrusion 31b is disposed on the exterior side of the supply tank 30. The wiring 32 is a line through which current flows. The supply tank-side cathode plate protrusion 31b is electrically connected to the current control unit 50 via the wiring 32.

[0048] The supply tank side cathode 31 may be, for example, an electrode using platinum, ruthenium, iridium oxide, or the like as an electrode catalyst, and more specifically, a platinum-iridium-titanium electrode, a platinum electrode, a ruthenium-titanium electrode, an iridium-titanium oxide electrode, or the like may be used.

[0049] The outlet 33 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 33 may be, for example, a check valve. When a check valve is used as the outlet 33, the hydrogen gas inside the supply tank 30 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 30, and the internal pressure of the supply tank 30 increases. This pressure opens the check valve, and the hydrogen gas is discharged to the external space of the supply tank 30.

[0050] The water level detector 23 detects the position of the liquid level S1 in the first aqueous solution L1. The water level detector 23 is, for example, a water level sensor. The water level detector 23 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 portions 12a, 13a, 14a, the electrolytic cell-side cathode plate immersed portion 15a, and the supply cell-side cathode plate immersed portion 31a.

[0051] The space purification device 1 may further include a water level detection unit 23 and a water supply unit 24. The water supply unit 24 supplies water to the electrolytic cell 10 based on the position of the liquid level S1 detected by the water level detection unit 23. More specifically, the water supply unit 24 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 portions 12a, 13a, 14a, the electrolytic cell-side cathode plate immersed portion 15a, and the supply cell-side cathode plate immersed portion 31a. The water supply unit 24 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 24 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. It may be placed to the side.

[0052] When the spatial purification device 1 is equipped with the water level detection unit 23 and the water supply unit 24, the electrolytic cell-side anode plate immersed portions 12a, 13a, 14a and the electrolytic cell-side cathode plate immersed portion 15a can be maintained immersed in the first aqueous solution L1. This prevents the electrolytic cell-side anode plate immersed portions 12a, 13a, 14a and the electrolytic cell-side cathode plate immersed portion 15a from being exposed to air due to a decrease in the first aqueous solution L1, thereby maintaining the electrolysis efficiency of diaphragm-less electrolysis.

[0053] Next, the details of the configuration of each electrode of the space purification device 1 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a partial cross-sectional plan view taken along line II-II in Fig. 1. In Fig. 2, the housing B shown in Fig. 1 is omitted.

[0054] The multiple electrolytic cell-side anodes 12, 13, 14 each have supply cell-side cathode-facing surfaces 12c, 13c, 14c facing the supply cell-side cathode 31. The multiple electrolytic cell-side anodes 12, 13, 14 each have electrolytic cell-side cathode-facing surfaces 12d, 13d, 14d facing the electrolytic cell-side cathode 15. Here, "facing" in this specification does not only include cases where the surfaces are positioned directly in front of each other, but also cases where the surfaces are positioned partially directly in front of each other.

[0055] The supply cell-side cathode-facing surface 12c of the electrolytic cell-side anode 12 does not have an electrode catalyst layer and the electrode substrate is exposed, while the electrolytic cell-side cathode-facing surface 12d has an electrode catalyst layer 12e. Similarly, the supply cell-side cathode-facing surface 14c of the electrolytic cell-side anode 14 does not have an electrode catalyst layer, and the electrolytic cell-side cathode-facing surface 12d has an electrode catalyst layer 14e. In other words, the electrolytic cell-side anodes 12, 14 are electrolytic cell-side single-sided catalytic anodes that have an electrode catalyst layer on one side. The electrolytic cell-side anodes 12, 14, which are electrolytic cell-side single-sided catalytic anodes, are used for diaphragm-less electrolysis but not for diaphragm-containing electrolysis.

[0056] The supply cell-side cathode-facing surface 13c of the electrolytic cell-side anode 13 is provided with an electrode catalyst layer 13e1 that promotes electrolysis. Similarly, the electrolytic cell-side cathode-facing surface 13d is provided with an electrode catalyst layer 13e2. In other words, the electrolytic cell-side anode 13 is an electrolytic cell-side double-sided catalytic anode that has electrode catalyst layers on both sides. The electrolytic cell-side anode 13, which is an electrolytic cell-side double-sided catalytic anode, is used for both diaphragm-less electrolysis and diaphragm-containing electrolysis.

[0057] The electrolytic cell-side cathode 15 has a first surface 15c facing the electrolytic cell-side cathode-facing surface 13d of the electrolytic cell-side anode 13, and a second surface 15d that is the back side of the first surface 15c (the yz plane on the negative side of the x-axis). The first surface 15c is provided with an electrode catalyst layer 15e1, and the second surface 15d is provided with an electrode catalyst layer 15e2. In other words, the electrolytic cell-side cathode 15 is an electrolytic cell-side double-sided catalytic cathode that has electrode catalyst layers on both sides. The electrolytic cell-side cathode 15 may also be an electrolytic cell-side single-sided catalytic cathode that has only the electrode catalyst layer 15e1 and no electrode catalyst layer 15e2.

[0058] The supply tank side cathode 31 has a first surface 31c facing the supply tank side cathode-facing surface 13c of the electrolytic tank side anode 13, and a second surface 31d that is the back side of the first surface 31c (the yz plane on the positive x-axis side). The first surface 31c is provided with an electrode catalyst layer 31e1, and the second surface 31d is provided with an electrode catalyst layer 31e2. In other words, the supply tank side cathode 31 is a supply tank side double-sided catalyst cathode that has electrode catalyst layers on both sides. The supply tank side cathode 31 may also be a supply tank side single-sided catalyst cathode that has only the electrode catalyst layer 31e1 and no electrode catalyst layer 31e2.

[0059] Here, the main cause of electrode deterioration accompanying electrolysis is deterioration of the electrode catalyst layer. In the space purification device 1 according to this embodiment, it is assumed that the amount of the first current used in the membraneless electrolysis is greater than the amount of the second current used in the membraneless electrolysis. When the amount of the first current used in the membraneless electrolysis is greater, the amount of elution of the electrode catalyst from the electrode surface increases. Therefore, in the space purification device 1 according to the present embodiment, a plurality of electrolytic cell-side anodes used for diaphragm-less electrolysis are provided, forming an electrolytic cell-side anode group 11 including a plurality of electrolytic cell-side anodes 12, 13, and 14.

[0060] On the other hand, in the space purification device 1 according to this embodiment, it is assumed that the amount of the second current used in the diaphragm-containing electrolysis is smaller than the amount of the first current used in the diaphragm-less electrolysis. Because the amount of the second current used in the diaphragm-containing electrolysis is smaller than the amount of the first current, the elution of the electrode catalyst is reduced, and electrode deterioration due to the diaphragm-containing electrolysis is less likely to progress than in the diaphragm-less electrolysis. Therefore, in the space purification device 1 according to this embodiment, only one anode, the electrolytic cell-side anode 13, is used in the diaphragm-containing electrolysis. By using an anode with a double-sided catalyst as one of the electrolytic cell-side anodes 13, electrolysis can be performed with the reaction concentrated at the electrolytic cell-side anode 13 in the diaphragm-containing electrolysis. In other words, it is preferable that at least one of the multiple electrolytic cell-side anodes be a double-sided catalyst anode.

[0061] If all of the multiple electrolytic cell-side anodes 12, 13, and 14 were double-sided catalytic anodes, the second current used in the diaphragm-equipped electrolysis would be distributed among the three anodes, slowing the migration rate of chloride ions that permeate the anion exchange membrane 40 from the second aqueous solution L2 stored in the supply tank 30 to the electrolytic cell-side anode 13. In contrast, in the space purification device 1 according to the present embodiment, only the electrolytic cell-side anode 13 is a double-sided catalytic anode. With this configuration, the second current used in the diaphragm-equipped electrolysis is concentrated at the electrolytic cell-side anode 13. The concentration of the second current at the electrolytic cell-side anode 13 increases the migration rate of chloride ions that permeate the anion exchange membrane 40 from the second aqueous solution L2 to the electrolytic cell-side anode 13 compared to when the electrolytic cell-side anodes 12 and 14 were double-sided catalytic anodes. The increased migration rate of chloride ions promotes convection in the first aqueous solution L1 stored in the electrolytic cell 10. Promoting convection in the first aqueous solution L1 can reduce the voltage required for electrolysis, thereby suppressing deterioration of the electrode catalyst layers 12e, 13e1, 13e2, and 14e of the electrolytic cell-side anodes 12, 13, and 14. Reducing the voltage required for electrolysis reduces the power consumption of the space purification device 1, thereby achieving energy savings.

[0062] As shown in Fig. 2, the space purification device 1 according to this embodiment includes a diaphragm-less electrolysis unit E1 and a diaphragm-containing electrolysis unit E2. In Fig. 2, the diaphragm-less electrolysis unit E1 is indicated by a dashed line, and the diaphragm-containing electrolysis unit E2 is indicated by a two-dot chain line. The current control unit 50 controls the first current passed through the diaphragm-less electrolysis unit E1 and the second current passed 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.

[0063] The diaphragm-less electrolysis unit E1 is provided in the electrolytic cell 10. The diaphragm-less electrolysis unit E1 produces hypochlorous acid by performing diaphragm-less electrolysis of the first aqueous solution L1 by passing a first current between the plurality of electrolytic cell-side anodes 12, 13, 14 that constitute the electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15. In other words, the diaphragm-less electrolysis unit E1 includes the plurality of electrolytic cell-side anodes 12, 13, 14 and the electrolytic cell-side cathode 15.

[0064] The membrane-equipped electrolysis unit E2 is provided across the electrolytic cell 10 and the supply cell 30. By passing a second current between the electrolytic cell-side anode 13, which is an electrolytic cell-side double-sided catalytic anode, and the supply cell-side cathode 31, membrane-equipped electrolysis is performed via the anion exchange membrane 40. In other words, the membrane-equipped electrolysis unit E2 includes the electrolytic cell-side anode 13, the supply cell-side cathode 31, and the anion exchange membrane 40.

[0065] The current control unit 50 controls the voltage so that the current values ​​flowing through the electrolytic cell-side anodes 12, 13, 14 constituting the electrolytic cell-side anode group 11 during diaphragm-less electrolysis in the diaphragm-less electrolysis unit E1 are equal to one another. More specifically, for example, when the current value flowing through the electrolytic cell-side cathode 15 during diaphragm-less electrolysis is 30 mA, 10 mA flows through the electrolytic cell-side anode 12, 10 mA flows through the electrolytic cell-side anode 13, and 10 mA flows through the electrolytic cell-side anode 14. That is, during diaphragm-less electrolysis, The current value is controlled by controlling the voltage so that the current ratio of electrolytic cell-side anode 12:electrolytic cell-side anode 13:electrolytic cell-side anode 14 is 1:1:1. When three electrolytic cell-side anodes are used, the current density per electrolytic cell-side anode is one-third of that when one electrolytic cell-side anode is used, and therefore the amount of electrocatalyst elution is one-third. Therefore, by controlling the voltage so that the current values ​​flowing through the multiple electrolytic cell-side anodes 12, 13, and 14 are equal during membraneless electrolysis, the current control unit 50 can suppress the elution of the electrocatalyst and prevent the deterioration of the electrocatalyst. Furthermore, by using multiple electrolytic cell-side anodes, electrode deterioration can be suppressed compared to when a single electrolytic cell-side anode is used, allowing the anodes to be used for a long period of time. Therefore, a desired amount of hypochlorous acid gas can be stably generated over a long period of time.

[0066] Furthermore, in the spatial purification device 1 according to this embodiment, the width of the multiple electrolytic cell-side anodes 12, 13, and 14 along the y-axis direction (the width in the short direction of the rectangle) is set to be equal to the width of the multiple electrolytic cell-side cathode 15 and the supply cell-side cathode 31 along the y-axis direction (the width in the short direction of the rectangle). Here, for example, if three of the multiple electrolytic cell-side anodes 12, 13, and 14 are joined together to form a single large electrolytic cell-side anode, the electrode catalysts located on the negative and positive sides of the y-axis will not be used for membraneless electrolysis, and the reaction may concentrate in the electrode catalyst layer in the central portion close to the electrolytic cell-side cathode 15. In other words, simply increasing the area of ​​the electrolytic cell-side anode makes it difficult to suppress electrode deterioration.

[0067] In contrast, the spatial purification device 1 according to this embodiment uses three electrolytic cell-side anodes, i.e., multiple electrolytic cell-side anodes 12, 13, and 14. The voltages applied to the multiple electrolytic cell-side anodes 12, 13, and 14 can be individually controlled, allowing for control of the current flowing through each of the multiple electrolytic cell-side anodes. Therefore, the current flowing through each of the multiple electrolytic cell-side anodes 12, 13, and 14 can be equalized regardless of the distance between the multiple electrolytic cell-side anodes 12, 13, and 14 and the electrolytic cell-side cathode 15. Therefore, by using multiple electrolytic cell-side anodes, deterioration of the electrode catalyst can be suppressed compared to using a single large electrolytic cell-side anode formed by connecting the three multiple electrolytic cell-side anodes 12, 13, and 14, allowing for longer anode life. Therefore, a desired amount of hypochlorous acid gas can be stably generated over a long period of time.

[0068] Here, we will explain in detail the chemical reactions that occur in the diaphragm-less electrolysis section E1 provided in the electrolytic cell 10 and the chemical reactions that occur in the diaphragm-equipped electrolysis section E2 provided between the electrolytic cell 10 and the supply cell 30. The following explains 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.

[0069] [Diaphragmless electrolysis section E1 (electrolytic cell 10)] FIG. 3 shows a list of reaction formulas that occur in the membraneless electrolysis section E1. Sodium chloride (NaCl) contained in the sodium chloride aqueous solution converts 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 chemical reactions shown in reaction formulas (a) to (g) in FIG. 3 occur. Reaction formula (a) in Figure 3: Electrolyzer side anode group 11 (chlorine generation reaction) At the electrolytic cell side anode group 11, chloride ions (Cl - ) is an electron (e - ) and chlorine (Cl2) is produced. Reaction formula (b) in Figure 3: Cathode 15 on the electrolytic cell side (hydrogen generation reaction) At the electrolytic cell-side cathode 15, water (H2O) in the first aqueous solution L1 converts electrons (e - ) and hydrogen (H2) and hydroxide ions (OH - ) occurs. Reaction formula (c) in Figure 3: Electrolyzer side anode group 11 (oxygen generation reaction) In the electrolytic cell-side anode group 11, electrons (e - ) is taken away, and oxygen (O2) and hydrogen ions (H + ) occurs. Reaction formula (d) in Figure 3: Hypochlorous acid generation reaction in the first aqueous solution L1 In the first aqueous solution L1 of the electrolytic cell 10, chlorine (Cl2) generated by reaction formula (a) of FIG. , a hydrolysis reaction occurs with the water (HO) in the first aqueous solution L1, generating hydrochloric acid (HCl) and hypochlorous acid (HClO). Hydrochloric acid (HCl) ionizes in the aqueous solution, generating hydrogen ions (H + ) and chloride ions (Cl - ) exists. Figure 3(e): Anion exchange membrane 40 When a voltage is applied to the membrane electrolysis unit E2 and a current flows, the first aqueous solution L1 stored in the electrolysis tank 10 generates electrons (e - ) and loses electrons (e - ) in the first aqueous solution L1, a force that maintains electrical neutrality acts, and negatively charged chloride ions (Cl -) is supplied from the second aqueous solution L2 stored in the supply tank 30 to the first aqueous solution L1 stored in the electrolytic tank 10 through the anion exchange membrane 40. In the first aqueous solution L1, the electrons (e - ) changes to chloride ions (Cl - ) can be said to be Reaction formula (f) in Figure 3: Hypochlorous acid generation reaction (equilibrium reaction formula) The equilibrium reaction formula for the hypochlorous acid generation reaction is shown below. - Depending on the increase or decrease of Cl in the electrolytic cell 10, the equilibrium state may shift to the right or to the left. - The current control described below is performed so that the apparent increase or decrease does not occur. Equation (g) in Figure 3: Chloride ion change during electrolysis Chlorine (Cl2) produced by reaction (a) in Figure 3 changes into hydrochloric acid (HCl) and hypochlorous acid (HClO) according to reaction (d) in Figure 3. This can be expressed in a single equation as equation (g) in Figure 3.

[0070] FIG. 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 group 11 used for the chlorine evolution reaction of reaction formula (a) in FIG. 3 is denoted as "x," and the ratio of the current used for the oxygen evolution reaction of reaction formula (c) in FIG. 3 is denoted as "1-x." Furthermore, the ratio of the current flowing in the electrolytic cell-side anode group 11 originating from the diaphragm-less electrolysis section E1 is denoted as "y," and the ratio of the current originating from the diaphragm-containing electrolysis section E2 is denoted as "1-y." Applying the above x and y to reaction formula (b) + (c) + (g) in FIG. 3 and taking into account the change shown in (e) in FIG. 3, reaction formula (a) in FIG. 4 is obtained.

[0071] When membrane-less electrolysis is performed in the membrane-less electrolysis section E1, the chloride ions in the electrolytic cell 10 are consumed and therefore reduced, but in the space purification device 1 according to this embodiment, chloride ions are supplied from the second aqueous solution L2 stored in the supply tank 30 to the first aqueous solution L1 stored in the electrolytic cell 10.

[0072] Here, the amount of chloride ions (Cl ) consumed by the membraneless electrolysis is transferred from the second aqueous solution L2 stored in the supply tank 30 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 change in the concentration of HClO does not occur are as follows: In this reaction, hypochlorous acid (HClO) evaporates as a gas, so it is not shown in reaction formulas (b) to (g) in Figure 4. Reaction formula (b) in Figure 4: Cl - This shows the conditions under which the apparent increase or decrease does not occur. Equation (c) in Figure 4: This shows the conditional equation for the coefficients x and y, which is modified from reaction equation (b) in Figure 4. ·Reaction equation (d) in Figure 4: Substituting equation (c) in Figure 4 into reaction equation (a) in Figure 4 gives reaction equation (d) in Figure 4. Reaction equation (e) in Figure 4: This shows a modification of reaction equation (d) in Figure 4.

[0073] 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.

[0074] In addition, the acid dissociation constant of hypochlorous acid (HClO) is approximately 7.5, so the first aqueous solution L1 It is necessary to maintain the pH unchanged. In reaction formula (e) of FIG. 4, hydroxide ions and hydrogen ions, which are the cause of the change in pH, react to form water and disappear from the reaction formula. Therefore, the amount of chloride ions (Cl) consumed by the membraneless electrolysis is transferred from the second aqueous solution L2 stored in the supply tank 30 to the first aqueous solution L1 stored in the electrolytic cell 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.

[0075] As described above, when the number of electrons flowing to the membraneless electrolysis section E1 changes, that is, when the ratio of the current flowing to the membraneless electrolysis section E1 and the current flowing to the membraneless electrolysis section E2 changes, the amount of chloride ions supplied from the supply tank 30 to the electrolytic cell 10 changes. For example, when the ratio of the current used for membraneless electrolysis changes, the amount of chloride ions (Cl - ) is supplied to the electrolytic cell 10. - When the current ratio is larger than the condition where the current does not increase or decrease (reaction formula (f) in FIG. 4), the Cl - The supply of Cl in the electrolytic cell 10 decreases. - decreases.

[0076] Cl in electrolytic cell 10 - If the electrolysis without a diaphragm is continued in a state where the electrolysis efficiency is reduced, the Cl in the electrolytic cell 10 will gradually decrease. - increases, and Cl - reaches a level that does not appear to increase or decrease.

[0077] On the other hand, the amount of current used for membraneless electrolysis is such that chloride ions (Cl - ) is supplied to the electrolytic cell 10. - When the current amount is larger than the condition where the amount of current does not apparently increase or decrease (reaction formula (g) in FIG. 4), the Cl supplied from the supply tank 30 to the electrolytic tank 10 - The supply of Cl in the electrolytic cell 10 increases. - increases.

[0078] The chloride ions (Cl - ) increases, the electrolysis efficiency of membrane-less electrolysis increases. If membrane-less electrolysis is continued in a state where the electrolysis efficiency has increased, the Cl in the electrolytic cell 10 gradually - decreases, and Cl - reaches a level that does not appear to increase or decrease.

[0079] In addition, Cl in the electrolytic cell 10 - When the amount of Cl in the electrolytic cell 10 increases, the equilibrium of reaction formula (f) in FIG. 3 shifts to the left, and the amount of chlorine generated increases.- By adjusting the current flowing through the membraneless electrolysis unit E1 and the current flowing through the membrane-containing electrolysis unit E2 so that the apparent change in the current does not increase or decrease, hypochlorous acid can be produced while suppressing the generation of chlorine.

[0080] [Diaphragm electrolysis part E2] Figure 5 is a list of reaction formulas that occur in the membrane-equipped electrolysis unit E2. The reactions in the second aqueous solution L2 in the supply tank 30 will be described. The only electrode arranged in the supply tank 30 is the supply tank-side cathode 31. When a predetermined voltage is applied to the membrane-equipped electrolysis unit E2, a current flows, electrons move, and the chemical reactions shown in Figure 5 occur. Reaction formula (a) in Figure 5: Supply tank side cathode 31 (hydrogen generation reaction) At the supply tank side cathode 31, the water (H2O) of the second aqueous solution L2 is converted into electrons (e - ) and hydrogen (H2) and hydroxide ions (OH - ) is generated. The hydrogen evaporates as a gas, and the hydroxide ions are used in reaction (c) in Figure 5, which will be described later.

[0081] Figure 5(b): Anion exchange membrane 40 When a voltage is applied to the membrane electrolysis unit E2 and a current flows, chloride ions (Cl ) contained in the second aqueous solution L2 stored in the supply tank 30 are dissolved in the water. - ) passes through the anion exchange membrane 40 and is supplied to the first aqueous solution L1, and the second aqueous solution L2 passes through the supply tank side cathode 31 and receives electrons (e - In other words, in the second aqueous solution L2, the chloride ions (Cl - ) after the change, electrons (e - ) can be said to be

[0082] Reaction formula (c) in Figure 5: Second aqueous solution L2 (magnesium hydroxide precipitation reaction) The magnesium ions (Mg 2+ ) and hydroxide ions (OH -) reacts with magnesium hydroxide (Mg(OH)2), which is a metal hydroxide precipitate, to form the precipitate. The solubility product of magnesium hydroxide (Mg(OH)2) is Ksp = 1.2 x 10 -11 (mol / L) 3 It is a substance that is extremely difficult to dissolve in aqueous solutions with a neutral to alkaline pH. For example, magnesium hydroxide, which can be dissolved in a weakly alkaline aqueous solution with a pH of 10, has a solubility of only 1.2 × 10 -3 In the second aqueous solution L2 of the supply tank 30, hydroxide ions (OH - ) is used to generate magnesium hydroxide precipitates, and hydroxide ions (OH - ) and the increase in pH of the second aqueous solution L2 can be suppressed.

[0083] 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, the second aqueous solution L2 stored in the supply tank 30 can be prevented from becoming strongly alkaline after electrolysis, thereby providing a space purification device with improved safety.

[0084] Furthermore, for example, a contractor may install the space purification device 1 according to this embodiment. After use of the space purification device 1, the space purification device 1 may be overturned or dropped when the contractor removes the installed space purification device or during transportation after removal. Here, when a magnesium chloride aqueous solution is used as the second aqueous solution L2, the second aqueous solution L2 after the electrolysis reaction is a weakly alkaline magnesium hydroxide aqueous solution. Therefore, even if the second aqueous solution L2 leaks outside the space purification device 1 due to overturning or dropping, safety can be improved compared to a space purification device that uses a sodium chloride aqueous solution as the second aqueous solution L2.

[0085] The above is a detailed description of the chemical reaction that occurs in the membraneless electrolysis section E1 provided in the electrolytic cell 10 and the chemical reaction that occurs in the membrane-containing electrolysis section E2 provided between the electrolytic cell 10 and the supply cell 30.

[0086] The current control unit 50 controls the chemical reaction. More specifically, the second current is controlled to replenish the chloride ions contained in the first aqueous solution L1 that have been reduced by the diaphragm-less electrolysis in the diaphragm-less electrolysis unit E1. By controlling the second current, chloride ions contained in the second aqueous solution L2 are permeated through the anion exchange membrane 40 and supplied to the first aqueous solution L1. Details will be described below with reference to FIG. 6.

[0087] 6 is a block diagram showing the current control unit 50 according to the embodiment 1. As shown in FIG.

[0088] The voltage acquisition unit 51 acquires the voltage between the electrolytic cell-side anode group 11 and the electrolytic cell-side cathode 15. The voltage acquisition unit 51 is, for example, a voltmeter. The calculation unit 52 calculates the conductivity of the first aqueous solution L1 based on the voltage acquired by the voltage acquisition unit 51. The estimation unit 53 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 52.

[0089] The current control unit 50 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 50 will be described below.

[0090] [1. When the first and second currents flow simultaneously] When the current control unit 50 simultaneously supplies the first current and the second current, it performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 53 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 40 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 53 is higher than a predetermined concentration: the current ratio between the first current and the second current is changed so as to reduce the amount of chloride ions that permeate from the second aqueous solution L2 through the anion exchange membrane 40 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 53 is a predetermined concentration: the current ratio between the first current and the second current is not changed.

[0091] [2. When the first current flows at a predetermined value and the second current is controlled at the same time] When the current control unit 50 controls the second current while causing the first current to flow at a predetermined value, it performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 53 is lower than a predetermined concentration: A second current is passed so as to increase the amount of chloride ions that pass through the anion exchange membrane 40 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 53 is higher than a predetermined concentration: The second current is stopped so that the supply of chloride ions from the second aqueous solution L2 to the first aqueous solution L1 is stopped. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 53 is a predetermined concentration: the first current and the second current are not changed.

[0092] [3. When the first or second current flows] When the current control unit 50 causes the first current or the second current to flow, it performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 53 is lower than a predetermined concentration: The first current is stopped and the second current is simultaneously passed so as to increase the amount of chloride ions that pass through the anion exchange membrane 40 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 53 is higher than a predetermined concentration: The second current is stopped and the first current is simultaneously passed so as to stop the supply of chloride ions from the second aqueous solution L2 to the first aqueous solution L1. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 53 is a predetermined concentration: the first current and the second current are not changed.

[0093] As described above, the current control unit 50 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.

[0094] In the above-mentioned "1. When the first current and the second current are passed simultaneously," if there is an increase or decrease in the chloride ion concentration in the first aqueous solution L1, the current ratio between the first current and the second current is changed. Because the first current and the second current are passed simultaneously, the increase or decrease in the chloride ion concentration in the first aqueous solution L1 can be minimized, and the concentration can be maintained at an optimal predetermined level.

[0095] 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," the second current is mainly passed or stopped when there is an increase or decrease in the chloride ion concentration of the first aqueous solution L1. In the above-mentioned "3. When the first current or the second current is passed," the second current is mainly passed or stopped when there is an increase or decrease in the chloride ion concentration of the first aqueous solution L1. When the voltage Vcc reaches the threshold, one of the first current and the second current is supplied and the other is stopped. Therefore, the chloride ion concentration in the first aqueous solution L1 can be maintained at a predetermined concentration. In the cases of 2 and 3 above, it is only necessary to control either the first current or the second current, so that current control is easy.

[0096] 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.

[0097] It is also possible to provide a plurality of current control units 50 and control the first current and the second current separately.

[0098] In addition, in FIG. 1, the inlet 20 and the outlet 22 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 from above, but the arrangement is not limited to this. For example, the positions of the inlet 20 and the outlet 22 may be reversed, or the inlet 20 and the outlet 22 may be at the same position on the x-axis, or the inlet 20 and the outlet 22 may be at the same position on the y-axis. However, when the inlet 20 and the outlet 22 are arranged, they are preferably arranged so that they are at the farthest positions on the xy plane. With such an arrangement, the time during which the inflowing air and hypochlorous acid are mixed in the mixing space 21 is longer, and therefore, more hypochlorous acid can be contained in the mixed air.

[0099] Next, a case will be described in which plane P1 (yz plane on the positive side of the x-axis) of the rectangular plate on the anion exchange membrane 40 side of the electrolytic cell-side anode 13 constituting the electrolytic cell-side anode group 11 and plane P2 (yz plane on the negative side of the x-axis) of the rectangular plate on the anion exchange membrane 40 side of the supply cell-side cathode 31 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 13 and the supply cell-side cathode 31. When a non-uniform electric field is generated between the electrolytic cell-side anode 13 and the supply cell-side cathode 31, the current distribution between the electrolytic cell-side anode 13 and the supply cell-side cathode 31 also becomes non-uniform.

[0100] When the current distribution between the electrolytic cell-side anode 13 and the supply cell-side cathode 31 becomes uneven, regions of high and low current density are generated. The high-current-density areas are more susceptible to deterioration of the electrode catalyst layer on the surfaces of the electrolytic cell-side anode 13 and the supply cell-side cathode 31 (hereinafter also referred to as each electrode plate), while the low-current-density areas are less susceptible to deterioration of the catalyst layer on the surface of each electrode plate. In other words, when an uneven electric field is generated between the electrolytic cell-side anode 13 and the supply cell-side cathode 31, the current distribution becomes uneven, and regions of different current densities may exist simultaneously on the same electrode plate. Therefore, uneven deterioration of the electrode catalyst layer may occur with use of each electrode plate. If the degree of deterioration of the electrode catalyst 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 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 reduced.

[0101] In contrast, in the spatial purification device 1 according to this embodiment, the planes P1 and P2 are arranged opposite to each other with the anion exchange membrane 40 interposed therebetween. This arrangement allows a uniform electric field to be generated between the electrolytic cell-side anode group 11 and the supply cell-side cathode 31, resulting in a uniform distribution of current between the two electrodes. This ensures that the deterioration of the catalytic layer on the surface of each electrode plate occurs uniformly, thereby preventing uneven deterioration of the catalytic layer on the surface of each electrode plate due to an uneven electric field, even when electrolysis is performed repeatedly. This prevents a decrease in electrolysis efficiency.

[0102] When membraneless electrolysis is carried out in an electrolytic cell at room temperature and pressure, the electrolyte in the first aqueous solution L1 is not used in the electrolysis, and oxygen and chlorine are mainly generated from the anode, which react with hypochlorous acid. Any electrolyte may be used as long as it does not cause a decrease in the concentration of hypochlorous acid by reacting with the electrodes, the electrolytic cell, and the anion exchange membrane and has electrical conductivity and is not reactive with the electrodes, the electrolytic cell, and the anion exchange membrane. More specifically, in addition to the first aqueous solution described above, 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 may be used. The metal chloride aqueous solution may be, for example, a dilute calcium chloride aqueous solution or a dilute magnesium chloride aqueous solution. The hydroxide salt aqueous solution may be, for example, a dilute sodium hydroxide aqueous solution or a dilute potassium hydroxide aqueous solution of 0.4 wt% (0.1 mol / L) or less. The acid salt aqueous solution may be, for example, a dilute hydrochloric acid aqueous solution of 0.4 wt% (0.1 mol / L) or less. The phosphate aqueous solution may be, for example, a disodium hydrogen phosphate aqueous solution, a sodium dihydrogen phosphate aqueous solution, a dipotassium hydrogen phosphate aqueous solution, or a potassium dihydrogen phosphate aqueous solution. As a specific example of a combination of the first aqueous solution, the pH may be adjusted by combining a dilute sodium chloride aqueous solution with a dilute sodium hydroxide aqueous solution.

[0103] <Embodiment 2> In the second embodiment, a description will be given of another configuration of the electrolytic cell-side anode included in the spatial purification device 1 according to the first embodiment. In the description of the second embodiment, the same components and current controls as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

[0104] 7 is a perspective view showing a spatial purification device 2 according to Embodiment 2. The first electrolytic cell-side anode 62 and the second electrolytic cell-side anode 63 constituting the electrolytic cell-side anode group 61 are arranged in a row along the x-axis direction with the shorter side of the rectangle aligned along the horizontal direction (y-axis direction) and with the flat surfaces of the rectangles of the anodes facing each other. In other words, from the negative side of the x-axis, the second electrolytic cell-side anode 63, the electrolytic cell-side cathode 15, and the first electrolytic cell-side anode 62 are arranged in a row with the flat surfaces of the rectangles facing each other.

[0105] The first electrolytic cell-side anode 62 and the second electrolytic cell-side anode 63 constituting the electrolytic cell-side anode group 61 are the first electrolytic cell-side anode plate 62 and the second electrolytic cell-side anode plate 63 having a plate shape. Plate shapes include rectangular and oblong shapes. The first electrolytic cell-side anode plate 62 and the second electrolytic cell-side anode plate 63 have electrolytic cell-side anode plate immersion portions 62a, 63a and electrolytic cell-side anode plate protrusions 62b, 63b, respectively.

[0106] The electrolytic cell-side anode group 61 is inserted from the outside of the electrolytic cell 10 toward the inside. In FIG. 7 , as an example, the electrolytic cell-side anode group 61 is inserted vertically (in the z-axis direction) from the bottom side of the electrolytic cell 10 (the xy plane side on the negative side of the z-axis). The electrolytic cell-side anode plate immersion portions 62a, 63a 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 entire electrolytic cell-side anode plate immersion portions 62a, 63a are immersed. That is, the first aqueous solution L1 is stored in the electrolytic cell 10 so that the liquid level S1 of the first aqueous solution L1 exceeds the upper ends (ends on the positive side of the z-axis) of the electrolytic cell-side anode plate immersion portions 62a, 63a.

[0107] The electrolytic cell-side anode plate protrusions 62b, 63b are arranged on the external side of the electrolytic cell 10. The wires 64, 65 are lines through which current flows. The electrolytic cell-side anode plate protrusion 62b is electrically connected to the current control unit 50 via the wire 64, and the electrolytic cell-side anode plate protrusion 63b is electrically connected to the current control unit 50 via the wire 64.

[0108] The electrolytic cell side anode group 61 may be, for example, an electrode using platinum, ruthenium, iridium oxide, or the like as an electrode catalyst, and more specifically, a platinum-iridium-titanium electrode, a platinum electrode, a ruthenium-titanium electrode, an iridium-titanium oxide electrode, or the like may be used.

[0109] 8 is a partial cross-sectional plan view taken along line VIII-VIII in FIG. The illustrated housing B is omitted. In Fig. 8, the details of each electrode of the space purification device 2 according to this embodiment will be described.

[0110] The first electrolytic cell side anode 62 comprises a supply cell side cathode facing surface 62c facing the supply cell side cathode 31, and a first electrolytic cell side cathode facing surface 62d facing the first surface 15c of the electrolytic cell side cathode 15.

[0111] The supply cell-side cathode-facing surface 62c of the first electrolytic cell-side anode 62 is provided with an electrode catalyst layer 62e1 that promotes electrolysis. Similarly, the first electrolytic cell-side cathode-facing surface 62d is provided with an electrode catalyst layer 62e2. In other words, the first electrolytic cell-side anode 62 is an electrolytic cell-side double-sided catalytic anode that has electrode catalyst layers on both sides.

[0112] The second electrolytic cell side anode 63 comprises a second electrolytic cell side cathode facing surface 63c that faces the second surface 15d of the electrolytic cell side cathode 15, and a substrate exposed surface 63d that is the back side (yz plane on the negative side of the x-axis) of the second electrolytic cell side cathode facing surface 63c.

[0113] The second electrolytic cell-side cathode-facing surface 63c is provided with an electrode catalyst layer 63e, but the substrate-exposed surface 63d is not provided with an electrode catalyst layer. In other words, the second electrolytic cell-side anode 63 is an electrolytic cell-side single-sided catalytic anode that has an electrode catalyst layer on one side.

[0114] Here, the main cause of electrode deterioration accompanying electrolysis is deterioration of the electrode catalyst layer. In the space purification device 1 according to this embodiment, it is assumed that the amount of the first current used for membraneless electrolysis is greater than the amount of the second current used for membrane-containing electrolysis. When the amount of the first current is greater, the amount of elution of the electrode catalyst due to electrolysis increases, which makes the electrode catalyst more susceptible to deterioration. Therefore, in the space purification device 2 according to this embodiment, a plurality of electrolytic cell-side anodes used for membraneless electrolysis are provided, forming an electrolytic cell-side anode group 61 including a first electrolytic cell-side anode 62 and a second electrolytic cell-side anode 63.

[0115] In contrast, in the space purification device 1 according to this embodiment, it is assumed that the amount of the second current used in the electrolysis with a diaphragm is smaller than the amount of the first current used in the electrolysis without a diaphragm. The amount of the second current used in the electrolysis with a diaphragm is smaller than the amount of the first current, and the elution of the electrode catalyst is reduced, so that the deterioration of the electrodes caused by the electrolysis with a diaphragm is less likely to progress than in the electrolysis without a diaphragm. Therefore, in the space purification device 2 according to this embodiment, only one anode, the first electrolytic cell-side anode 62, is used in the electrolysis with a diaphragm. By using the first electrolytic cell-side anode 62 as the only anode equipped with a double-sided catalyst, electrolysis can be performed with the reaction concentrated at the first electrolytic cell-side anode 62 in the electrolysis with a diaphragm.

[0116] The diaphragm-free electrolysis unit E3 is provided in the electrolytic cell 10. The diaphragm-free electrolysis unit E3 produces hypochlorous acid by electrolyzing the first aqueous solution L1 without a diaphragm by passing a first current between the first electrolytic cell-side anode 62 and the second electrolytic cell-side anode 63 constituting the electrolytic cell-side anode group 61 and the electrolytic cell-side cathode 15. In other words, the diaphragm-free electrolysis unit E3 includes the first electrolytic cell-side anode 62, the second electrolytic cell-side anode 63, and the electrolytic cell-side cathode 15. Current control in the diaphragm-free electrolysis unit E3 is similar to the current control in the diaphragm-free electrolysis unit E1 of the first embodiment.

[0117] The membrane-equipped electrolysis unit E4 is provided across the electrolytic cell 10 and the supply cell 30. Membrane-equipped electrolysis is performed via the anion exchange membrane 40 by passing a second current between the first electrolytic cell-side anode 62, which is an electrolytic cell-side double-sided catalytic anode, and the supply cell-side cathode 31. In other words, the membrane-equipped electrolysis unit E4 includes the first electrolytic cell-side anode 62, the supply cell-side cathode 31, and the anion exchange membrane 40. Current control in the membrane-equipped electrolysis unit E4 is similar to that in the membrane-equipped electrolysis unit E2 of the first embodiment.

[0118] The current control unit 50 controls the voltage so that the current values ​​flowing through the first electrolytic cell-side anode 62 and the second electrolytic cell-side anode 63 constituting the electrolytic cell-side anode group 61 during diaphragm-free electrolysis in the diaphragm-free electrolysis unit E1 are equal. More specifically, for example, when the current value flowing through the electrolytic cell-side cathode 15 during diaphragm-free electrolysis is 30 mA, 15 mA flows through the first electrolytic cell-side anode 62 and 15 mA flows through the second electrolytic cell-side anode 63. That is, during diaphragm-free electrolysis, the current values ​​are controlled by controlling the voltage so that the current ratio between the first electrolytic cell-side anode 62 and the second electrolytic cell-side anode 63 is 1:1. Compared to when one electrolytic cell-side anode is used, when two electrolytic cell-side anodes are used, the current density per electrolytic cell-side anode is half, and therefore the amount of electrode catalyst elution is half. Therefore, by controlling the voltage so that the current values ​​flowing through the first electrolytic cell-side anode 62 and the second electrolytic cell-side anode 63 during membraneless electrolysis are equal, the current control unit 50 can suppress elution of the electrode catalyst and prevent deterioration of the electrode catalyst. Furthermore, by using multiple electrolytic cell-side anodes, electrode deterioration can be prevented compared to when a single electrolytic cell-side anode is used, allowing the anodes to be used for a long period of time. Therefore, the desired amount of hypochlorous acid gas can be stably generated over a long period of time.

[0119] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention.

[0120] An outline of one aspect of the present disclosure is as follows.

[0121] (Item 1) an electrolytic cell for storing a first aqueous solution containing chloride ions; a supply tank for storing a second aqueous solution containing chloride ions at a higher concentration than the first aqueous solution and supplying chloride ions to the first aqueous solution; The electrolytic cell is provided with an electrolytic cell-side anode group composed of a plurality of electrolytic cell-side anodes; and an electrolytic cell-side cathode; a supply tank-side cathode provided in the supply tank; an anion exchange membrane connecting the electrolytic cell and the supply cell so as to be permeable to anions based on a voltage applied between the electrolytic cell-side anode group and the supply cell-side cathode; a membrane-less electrolysis unit provided in the electrolytic cell that generates hypochlorous acid by performing membrane-less electrolysis of the first aqueous solution by passing a first current between the electrolytic cell-side anode group and the electrolytic cell-side cathode; a membrane-containing electrolysis section provided between the electrolytic cell and the supply cell, which performs 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 the second current so as to compensate for chloride ions contained in the first aqueous solution that have been reduced by the membrane-less electrolysis, thereby causing chloride ions contained in the second aqueous solution to permeate through the anion exchange membrane and be supplied to the first aqueous solution, the current control unit controls the current values ​​flowing through the plurality of electrolytic cell-side anodes during the diaphragm-less electrolysis so that the current values ​​are equal to each other. Space purification device. (Item 2) The plurality of electrolytic cell-side anodes are an electrolytic cell-side cathode facing surface facing the electrolytic cell-side cathode; a supply tank-side cathode facing surface facing the supply tank-side cathode, at least one of the plurality of electrolytic cell-side anodes is an electrolytic cell-side double-sided catalytic anode having electrode catalyst layers that promote electrolysis on both a surface facing the electrolytic cell-side cathode and a surface facing the supply cell-side cathode, the electrolytic cell-side anode other than the electrolytic cell-side double-sided catalytic anode is an electrolytic cell-side single-sided catalytic anode that has the electrode catalyst layer on a surface facing the electrolytic cell-side cathode and does not have the electrode catalyst layer on a surface facing the supply cell-side cathode, Item 1. The space purification device according to item 1. (Item 3) Item 3. The spatial purification device according to item 2, wherein the electrolytic cell-side double-sided catalytic anode is disposed closer to the supply cell-side electrode than the electrolytic cell-side single-sided catalytic anode. (Item 4) The electrolytic cell side cathode is The first page and a second surface that is the reverse side of the first surface, Among the plurality of electrolytic cell-side anodes, One electrolytic cell side anode is a first electrolytic cell-side cathode-opposing surface that faces the first surface of the electrolytic cell-side cathode; a supply tank-side cathode facing surface facing the supply tank-side cathode, an electrolytic cell-side double-sided catalytic anode having an electrode catalyst layer on both the first electrolytic cell-side cathode-facing surface and the supply cell-side cathode-facing surface, The other electrolytic cell side anode is a second electrolytic cell-side cathode facing surface facing the second surface of the electrolytic cell-side cathode; a substrate exposed surface that is the back side of the cathode-facing surface on the second electrolytic cell side, the electrolytic cell-side single-sided catalytic anode is provided with the electrode catalyst layer on the surface facing the second electrolytic cell-side cathode, and is not provided with the electrode catalyst layer on the exposed surface of the substrate; Item 1. The space purification device according to item 1. (Item 5) the second aqueous solution is a metal chloride aqueous solution containing metal ions and the chloride ions, By performing the diaphragm electrolysis, supplying the chloride ions contained in the second aqueous solution stored in the supply tank to the first aqueous solution stored in the electrolytic tank through the anion exchange membrane so as to replenish the chloride ions contained in the first aqueous solution that have been reduced by the membrane-less electrolysis; In the supply tank, metal ions contained in the second aqueous solution are reacted with hydroxide ions generated by the membrane electrolysis to form a precipitate of metal hydroxide. Item 2 or 4. The space purification device according to item 2 or 4. (Item 6) The current control unit a voltage acquisition unit that acquires a voltage between the electrolytic cell-side anode group 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; an estimation unit that estimates the concentration of the first aqueous solution based on the conductivity calculated by the calculation unit, The current control unit The first current and the second current are simultaneously applied, When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, a current ratio between the first current and the second current is changed so that an amount of chloride ions that permeates the anion exchange membrane from the second aqueous solution and is supplied to the first aqueous solution is increased; When the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, the current ratio between the first current and the second current is changed so that the amount of chloride ions that permeate from the second aqueous solution through the anion exchange membrane and are supplied to the first aqueous solution is reduced. The space purification device according to claim 2 or 4. (Item 7) When the chloride ion concentration of the first aqueous solution is the predetermined concentration, the first current and the The current ratio of the two currents is not changed. Item 6. The space purification device according to item 6. (Item 8) 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; an estimation unit that estimates the concentration of the first aqueous solution based on the conductivity calculated by the calculation unit, The current control unit The first current is passed at a predetermined value while the second current is controlled; The control of the second current is When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, the second current is applied so as to increase the amount of chloride ions 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, the second current is stopped so that the supply of chloride ions from the second aqueous solution to the first aqueous solution is stopped. Item 2 or 4. The space purification device according to item 2 or 4. (Item 9) 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; an estimation unit that estimates the concentration of the first aqueous solution based on the conductivity calculated by the calculation unit, The current control unit When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, the first current is stopped and the second current is simultaneously applied so that the amount of chloride ions permeating from the second aqueous solution through the anion exchange membrane and supplied to the first aqueous solution increases; When the chloride ion concentration of the first aqueous solution is higher than a predetermined concentration, stopping the second current and simultaneously applying the first current so as to stop the supply of chloride ions from the second aqueous solution to the first aqueous solution; Item 2 or 4. The space purification device according to item 2 or 4. (Item 10) The non-diaphragm electrolysis unit is the electrolytic cell-side anode group; the electrolytic cell-side cathode, The membrane electrolysis unit is the electrolytic cell-side anode; the supply tank side cathode; The anion exchange membrane, Item 1. The space purification device according to item 1. (Item 11) a housing for housing the electrolytic cell and the supply cell; an inlet that is disposed in the housing above a liquid level of the first aqueous solution stored in the electrolytic cell and through which air flows in from an external space of the housing; A mixing space for mixing the volatilized hypochlorous acid with the air flowing in from the inlet; an outlet through which the mixed air flows out to the exterior space, Item 1. The space purification device according to item 1. [Explanation of symbols]

[0122] 1. Space Purification Device 2. Space Purification Device 10 Electrolytic cell 11 Electrolyzer side anode group 12 Electrolyzer side anode 12a Electrolytic tank side anode plate immersion part 12b Electrolytic tank side anode plate protrusion 12c Supply tank side cathode facing surface 12d Electrolytic cell side cathode facing surface 12e Electrocatalyst layer 13 Electrolyzer side anode 13a Electrolytic tank side anode plate immersion part 13b Electrolytic tank side anode plate protrusion 13c Supply tank side cathode facing surface 13d Cathode facing surface on electrolytic cell side 13e1 Electrode catalyst layer 13e2 Electrode catalyst layer 14 Electrolyzer side anode 14a Electrolytic tank side anode plate immersion part 14b Electrolytic tank side anode plate protrusion 14c Supply tank side cathode facing surface 14d Electrolytic cell side cathode facing surface 14e Electrocatalyst layer 15 Electrolytic cell side cathode 15a Electrolytic tank side cathode plate immersion part 15b Electrolytic cell side cathode plate protrusion 15c page 1 15d 2nd side 15e1 Electrode catalyst layer 15e2 Electrode catalyst layer 16 Wiring 17 Wiring 18 Wiring 19 Wiring 20 Inlet 21 Mixed Space 22 outflow 23 Water level outlet 24 Water Supply Department 30 supply tanks 31 Supply tank side cathode 31a Supply tank side cathode plate impregnation part 31b Supply tank side cathode plate protrusion 31c Page 1 31d Page 2 31e1 Electrode catalyst layer 31e2 Electrode catalyst layer 32 Wiring 33 outlet 40 anion exchange membrane 50 Current Control Unit 51 Electric pressure acquisition part 52 Calculation Department 53 Presumption 61 Anode group on the electrolytic cell side 62 Anode on the first electrolytic cell side 62a Anode plate impregnation part on the electrolytic cell side 62b Anode plate protrusion on the electrolytic cell side 62c Supply tank side cathode facing surface 62d Cathode-facing surface of the first electrolytic cell 62e1 electrode catalyst layer 62e2 electrode catalyst layer 63 Anode on the second electrolytic cell side 63a Anode plate impregnation part on the electrolytic cell side 63b Anode plate protrusion on the electrolytic cell side 63c Cathode-facing surface of the second electrolytic cell 63d exposed surface of substrate 63e electrode catalyst layer 64 Wiring 65 Wiring B box E1 diaphragmless electrolysis unit E2 diaphragm electrolysis unit E3 diaphragmless electrolysis unit E4 with diaphragm electrolysis unit L1 1st aqueous solution L2 Second aqueous solution S1 liquid level S2 liquid level

Claims

1. an electrolytic cell for storing a first aqueous solution containing chloride ions; a supply tank for storing a second aqueous solution containing chloride ions at a higher concentration than the first aqueous solution and supplying chloride ions to the first aqueous solution; The electrolytic cell is provided with an electrolytic cell-side anode group composed of a plurality of electrolytic cell-side anodes; and an electrolytic cell-side cathode; a supply tank-side cathode provided in the supply tank; an anion exchange membrane connecting the electrolytic cell and the supply cell so as to be permeable to anions based on a voltage applied between the electrolytic cell-side anode group and the supply cell-side cathode; a membrane-less electrolysis unit provided in the electrolytic cell, which generates hypochlorous acid by performing membrane-less electrolysis of the first aqueous solution by passing a first current between the electrolytic cell-side anode group and the electrolytic cell-side cathode; a membrane-with-diaphragm electrolysis section provided across the electrolytic cell and the supply cell, which performs membrane-with-diaphragm electrolysis via the anion exchange membrane by passing a second current between the electrolytic cell-side anode and the supply cell-side cathode; a current control unit that controls the second current so as to compensate for chloride ions contained in the first aqueous solution that have been reduced by the membrane-less electrolysis, thereby causing chloride ions contained in the second aqueous solution to permeate through the anion exchange membrane and supply them to the first aqueous solution, the current control unit controls the current values ​​flowing through the plurality of electrolytic cell-side anodes during the diaphragm-less electrolysis so that the current values ​​are equal to each other. Space purification device.

2. The plurality of electrolytic cell-side anodes are an electrolytic cell-side cathode facing surface facing the electrolytic cell-side cathode; a supply tank-side cathode facing surface facing the supply tank-side cathode, at least one of the plurality of electrolytic cell-side anodes is an electrolytic cell-side double-sided catalytic anode having electrode catalyst layers that promote electrolysis on both the electrolytic cell-side cathode-facing surface and the feed cell-side cathode-facing surface, the electrolytic cell-side anode other than the electrolytic cell-side double-sided catalytic anode is an electrolytic cell-side single-sided catalytic anode that has the electrode catalyst layer on a surface facing the electrolytic cell-side cathode and does not have the electrode catalyst layer on a surface facing the supply cell-side cathode, The space purification device according to claim 1 .

3. The spatial purification device according to claim 2 , wherein the electrolytic cell-side double-sided catalytic anode is disposed closer to the supply cell-side electrode than the electrolytic cell-side single-sided catalytic anode.

4. The electrolytic cell side cathode is The first page and a second surface that is the back side of the first surface, Among the plurality of electrolytic cell-side anodes, One electrolytic cell side anode is a first electrolytic cell-side cathode-opposing surface that faces the first surface of the electrolytic cell-side cathode; a supply tank-side cathode facing surface facing the supply tank-side cathode, an electrolytic cell-side double-sided catalytic anode having an electrode catalyst layer on both the first electrolytic cell-side cathode-facing surface and the supply cell-side cathode-facing surface, The other electrolytic cell side anode is a second electrolytic cell-side cathode facing surface facing the second surface of the electrolytic cell-side cathode; a substrate exposed surface that is the back side of the second electrolytic cell-side cathode-facing surface, the electrolytic cell-side single-sided catalytic anode is provided with the electrode catalyst layer on the surface facing the second electrolytic cell-side cathode, and is not provided with the electrode catalyst layer on the exposed surface of the substrate; The space purification device according to claim 1 .

5. the second aqueous solution is a metal chloride aqueous solution containing metal ions and the chloride ions, By performing the diaphragm electrolysis, supplying the chloride ions contained in the second aqueous solution stored in the supply tank to the first aqueous solution stored in the electrolytic tank through the anion exchange membrane so as to replenish the chloride ions contained in the first aqueous solution that have been reduced by the membrane-less electrolysis; In the supply tank, metal ions contained in the second aqueous solution are reacted with hydroxide ions generated by the membrane electrolysis to form a precipitate of metal hydroxide. The space purification device according to claim 2 or 4.

6. The current control unit a voltage acquisition unit that acquires a voltage between the electrolytic cell-side anode group 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; an estimation unit that estimates a concentration of the first aqueous solution based on the conductivity calculated by the calculation unit, The current control unit The first current and the second current are simultaneously applied, When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, a current ratio between the first current and the second current is changed so that an amount of chloride ions that permeates the anion exchange membrane from the second aqueous solution and is supplied to the first aqueous solution is increased; When the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, the current ratio between the first current and the second current is changed so that the amount of chloride ions that permeate from the second aqueous solution through the anion exchange membrane and are supplied to the first aqueous solution is reduced. The space purification device according to claim 2 or 4.

7. When the chloride ion concentration of the first aqueous solution is the predetermined concentration, the current ratio of the first current to the second current is not changed. The space purification device according to claim 6.

8. 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; an estimation unit that estimates a concentration of the first aqueous solution based on the conductivity calculated by the calculation unit, The current control unit The first current is caused to flow at a predetermined value while the second current is controlled; The control of the second current includes: When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, the second current is applied so as to increase the amount of chloride ions 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, the second current is stopped so that the supply of chloride ions from the second aqueous solution to the first aqueous solution is stopped. The space purification device according to claim 2 or 4.

9. 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; an estimation unit that estimates a concentration of the first aqueous solution based on the conductivity calculated by the calculation unit, The current control unit When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, the first current is stopped and the second current is simultaneously applied so that the amount of chloride ions permeating from the second aqueous solution through the anion exchange membrane and supplied to the first aqueous solution increases; When the chloride ion concentration of the first aqueous solution is higher than a predetermined concentration, stopping the second current and simultaneously applying the first current so as to stop the supply of chloride ions from the second aqueous solution to the first aqueous solution; The space purification device according to claim 2 or 4.

10. The non-diaphragm electrolysis unit is the electrolytic cell-side anode group; the electrolytic cell-side cathode, The membrane electrolysis unit is the electrolytic cell-side anode; the supply tank side cathode; The anion exchange membrane, The space purification device according to claim 1 .

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

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