Space purification device

Abstract

To provide a space purification device that suppresses strong alkalization of an aqueous solution stored in a supply tank after electrolysis, thereby improving safety.SOLUTION: There is provided a space purification device 1 comprising an electrolytic bath 10 for retaining a first aqueous solution L1, a supply tank 20 for retaining a second aqueous solution L2 and supplying chloride ions to the first aqueous solution L1, and a negative ion exchange membrane 30 that connects the electrolytic bath 10 and the supply tank 20 in a manner enabling permeation by negative ions. The second aqueous solution L2 is a metal chloride aqueous solution. Membrane electrolysis is performed, so that the chloride ions contained in the second aqueous solution L2 retained in the supply tank 20 permeate through the negative ion exchange membrane 30 and are supplied to the first aqueous solution L1 retained in the electrolytic bath 10 so as to supplement chloride ions contained in the first aqueous solution L1, which is reduced by membraneless electrolysis. The metal ions contained in the second aqueous solution L2 and hydroxide ions generated by the membrane electrolysis are reacted within the supply tank 20 to form precipitate of a metal hydroxide.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 by using hypochlorous acid generated by electrolyzing an aqueous solution of sodium chloride. [Prior art documents] [Patent documents]

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

[0004] However, when generating hypochlorous acid water by electrolysis of sodium chloride solution in a space purification device, sodium hydroxide, which is a strong alkali, may be generated. When such a space purification device is made small and installed at a specified installation location by a contractor, it is expected that the contractor will remove the space purification device after use, or the space purification device will be overturned or dropped during transportation after removal. In this case, there is a problem that the generated sodium hydroxide, which is a strong alkali, may leak outside the space purification device.

[0005] The present invention has been made in consideration of the above problems, and provides a space purification device that suppresses strong alkalinity after electrolysis of the aqueous solution stored in the supply tank, thereby improving safety. [Means for solving the problem]

[0006] The spatial purification device according to the present invention includes an electrolytic cell for storing a first aqueous solution containing chloride ions, a supply cell for storing a second aqueous solution containing a higher concentration of chloride ions than the first aqueous solution and supplying chloride ions to the first aqueous solution, an electrolytic cell-side anode and an electrolytic cell-side cathode provided in the electrolytic cell, a supply cell-side cathode provided in the supply cell, an anion exchange membrane connecting the electrolytic cell and the supply cell to allow anions to pass therethrough based on a voltage applied between the electrolytic cell-side anode and the supply cell-side cathode, a membrane-less electrolysis unit provided in the electrolytic cell for generating hypochlorous acid by electrolyzing the first aqueous solution without a membrane by passing a first current between the electrolytic cell-side anode and the electrolytic cell-side cathode, and and a membrane-with-diaphragm electrolysis section 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, wherein the second aqueous solution is a metal chloride aqueous solution containing metal ions and chloride ions, and by performing membrane-with-diaphragm electrolysis, chloride ions contained in the second aqueous solution stored in the supply cell are supplied to the first aqueous solution stored in the electrolytic cell through the anion exchange membrane so as to replenish the chloride ions contained in the first aqueous solution reduced by the membrane-less electrolysis, and in the supply cell, the metal ions contained in the second aqueous solution react with hydroxide ions generated by the membrane-with-diaphragm electrolysis to form a precipitate of metal hydroxide. Effect of the Invention

[0007] According to the present invention, it is possible to provide a space purification device which suppresses strong alkalinity after electrolysis of an aqueous solution and has improved safety. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a space purification device according to an embodiment. [Diagram 2] FIG. 2 is a partial cross-sectional front view showing the spatial purification device of FIG. [Diagram 3] FIG. 3 shows a list of reaction formulas occurring in the membraneless electrolysis section. [Figure 4] FIG. 4 shows the reaction formula including the ratio of the current flowing in the electrolytic section without a diaphragm to the current flowing in the electrolytic section with a diaphragm. [Diagram 5] FIG. 5 shows a list of reaction formulas occurring in the membrane electrolysis section. [Figure 6] FIG. 6 is a block diagram illustrating a current control unit according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. The right-handed xyz coordinate system shown in the drawings is for the convenience of explaining the positional relationship of the components. Unless otherwise specified, the positive direction of the z axis is vertically upward. In addition, the xy plane is a horizontal plane, which is common to all drawings.

[0010] <Embodiment> 1 is a perspective view showing an outline of a space purification device 1 according to an embodiment. The space purification device 1 performs electrolysis of a first aqueous solution L1 containing chloride ions in an electrolytic cell 10 described below, and generates and volatilizes hypochlorous acid. The space purification device 1 removes bacteria, fungi, viruses, odors, and the like contained in the air in the external space of the space purification device 1 by causing the volatilized hypochlorous acid to flow out of a housing B constituting the space purification 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 a so-called air conditioner, the periphery of an electric fan, the periphery of a circulator, the periphery of a ceiling fan, inside a humidifier, inside an air purifier, and the like.

[0012] The spatial purification device 1 includes a housing B, an electrolytic cell 10, a supply cell 20, an anion exchange membrane 30, and a current control unit 40.

[0013] The housing B houses the electrolytic cell 10, the supply cell 20, the anion exchange membrane 30, and the current control unit 40. That is, the space purification device 1 may be a unit integrated with the housing B. The shape of the housing B can be appropriately changed 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, about 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 a state in which the first aqueous solution L1 is stored in the electrolytic cell 10. The first aqueous solution L1 is, for example, an aqueous solution in which an electrolyte having electrical conductivity is dissolved, and specifically, a dilute chloride aqueous solution having a predetermined chloride ion concentration. More specifically, the first aqueous solution L1 is, for example, a sodium chloride aqueous solution or a dilute potassium chloride aqueous solution.

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

[0016] The supply tank 20 is a tank for storing the second aqueous solution L2 containing chloride ions. The chloride ions contained in the second aqueous solution L2 of the electrolytic cell 20 permeate through the anion exchange membrane 30 and are supplied to the first aqueous solution L1 of the electrolytic cell 10.

[0017] The supply tank 20 is a tank for storing the second aqueous solution L2 containing chloride ions and supplying the chloride ions to the first aqueous solution L1. FIG. 1 shows a state in which the second aqueous solution L2 is stored in the supply tank 20. The chloride ion concentration of the second aqueous solution L2 is higher than that of the first aqueous solution L1. As the solute of the second aqueous solution L2, a substance having a safety level similar to that of sodium chloride in the GHS (Globally Harmonized System of Classification and Labelling of Chemicals) classification is preferable in order to ensure safety in the event of leakage. Specifically, the second aqueous solution L2 is a metal chloride aqueous solution containing metal ions and chloride ions. The second aqueous solution L2 is subjected to a diaphragm electrolysis described later, whereby the chloride ions contained in the second aqueous solution L2 react with the hydroxide ions generated by the diaphragm electrolysis to form a precipitate of a metal hydroxide. 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 8 hours every day for a year, the respective volumes of the electrolytic cell 10 and the supply cell 20 are preferably set such that, for example, the volume of the supply cell 20 is about 12 times or more the volume of the electrolytic cell 10. By setting such a volume ratio, the supply cell 20 can store the second aqueous solution L2 containing a sufficient amount of chloride ions required to be supplied to the first aqueous solution L1 of the electrolytic cell 10. Therefore, chloride ions can be stably supplied from the second aqueous solution L2 stored in the supply cell 20 to the first aqueous solution L1 stored in the electrolytic cell 10. The amount of the first aqueous solution L1 stored in the electrolytic cell 10 is, for example, about 2 to 10 mL.

[0019] The anion exchange membrane 30 is a membranous member that connects the electrolytic cell 10 and the supply cell 20 in a manner that allows anions to pass therethrough, based on a voltage applied between the electrolytic cell 10 and the supply cell 20. More specifically, when a voltage is applied between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21, which will be described later, membrane-type electrolysis is performed via the anion exchange membrane 30. By the membrane-type electrolysis using the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21, chloride ions contained in the second aqueous solution L2 permeate the anion exchange membrane 30 and are supplied to the first aqueous solution L1 (indicated by a thick black arrow in the negative direction of the x-axis).

[0020] The anion exchange membrane 30 in this embodiment is not a type of anion exchange membrane through which anions permeate due to osmotic pressure without using electricity. In addition, the anion exchange membrane 30 does not allow sodium ions, which are cations, to permeate. More specifically, when chloride ions contained in the second aqueous solution L2 are permeated through the anion exchange membrane 30 and supplied to the first aqueous solution L1 by membrane electrolysis using the electrolytic cell side anode plate 11 and the supply cell side cathode plate 21, sodium ions, which are cations, do not permeate the anion exchange membrane 30. The anion exchange membrane 30 is, for example, a hydrocarbon-based anion exchange membrane, and includes membranes having monovalent anion selective permeability, alkali resistance, and high temperature resistance.

[0021] The anion exchange membrane 30 is disposed between the electrolytic cell 10 and the supply cell 20. For example, the surface of the electrolytic cell 10 facing the supply cell 20 (the yz plane on the positive side of the x-axis) and the surface of the supply cell 20 facing the electrolytic cell 10 (the yz plane on the negative side of the x-axis) may each be formed of a frame-shaped member. When the opposing surfaces of the electrolytic cell 10 and the supply cell 20 are each formed of a frame-shaped member, the anion exchange membrane 30 may be disposed so as to be fitted into the frame-shaped member.

[0022] The current control unit 40 controls the current used in the diaphragmless electrolysis and the diaphragm-containing electrolysis. More specifically, the current control unit 40 controls the current used in the diaphragmless electrolysis performed using a pair of electrolytic cell side anode 11 and electrolytic cell side cathode 12 arranged in the electrolytic cell 10. The current control unit 40 controls the current used in the membrane electrolysis, which is performed via the anion exchange membrane 30 using a pair of the electrolytic cell side anode 11 and the supply cell side cathode 21, across the electrolytic cell 10 and the supply cell 20. The electrolytic cell side anode 11 is used for both the diaphragmless electrolysis and the diaphragm-containing electrolysis. That is, the space purification device 1 according to this embodiment has one anode and two cathodes, that is, a total of three electrodes. Since the supply cell 20 has only cathodes, chlorine is not generated in the supply cell 20 by a chemical reaction described later.

[0023] Hereinafter, the details of each component will be described more specifically with reference to FIG. 1 and FIG. As shown in FIG. 1, the electrolytic cell 10 includes an electrolytic cell-side anode 11 , an electrolytic cell-side cathode 12 , a wire 13 , a wire 14 , an inlet 15 , a mixing space 16 and an outlet 17 .

[0024] The electrolytic cell side anode 11 and the electrolytic cell side cathode 12 are a pair of electrodes used in the electrolysis of the first aqueous solution L1. As shown in Fig. 1, no diaphragm such as an ion exchange membrane is provided between the electrolytic cell side anode 11 and the electrolytic cell side cathode 12. That is, the electrolysis of the first aqueous solution L1 performed using the pair of the electrolytic cell side anode 11 and the electrolytic cell side cathode 12 is membrane-less electrolysis. Hypochlorous acid used for space purification is generated by the membrane-less electrolysis of the first aqueous solution L1 performed using the pair of the electrolytic cell side anode 11 and the electrolytic cell side cathode 12.

[0025] The electrolytic cell side anode 11 and the electrolytic cell side cathode 12 each have a plate shape. That is, the electrolytic cell side anode 11 is an electrolytic cell side anode plate 11 having a plate shape, and the electrolytic cell side cathode 12 is an electrolytic cell side cathode plate 12 having a plate shape. The plate shape includes a rectangular shape and a rectangular shape. Hereinafter, the electrolytic cell side anode 11 is also referred to as the electrolytic cell side anode plate 11. The electrolytic cell side cathode 12 is also referred to as the electrolytic cell side cathode plate 12.

[0026] As an example, a case where the plate shape of the electrolytic cell side anode plate 11 and the electrolytic cell side cathode plate 12 are rectangular will be described. The electrolytic cell side anode plate 11 and the electrolytic cell side cathode plate 12 are arranged such that the short side direction of the rectangle is along the vertical direction (z-axis direction). This arrangement can prevent bubbles generated by chemical reactions from adhering to both sides of the rectangle of each electrode. Furthermore, compared to a case where the long side direction of the rectangle is arranged along the vertical direction (z-axis direction), when the short side direction is arranged along the vertical direction (z-axis direction), it is possible to prevent bubbles generated at the lower part (negative side of the z-axis) of the electrolytic cell side anode plate 11 and the electrolytic cell side cathode plate 12 from adhering to the upper part (positive side of the z-axis) of the electrolytic cell side anode plate 11 and the electrolytic cell side cathode plate 12.

[0027] The electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12 are arranged such that the longitudinal direction of the rectangle is along the horizontal direction (y-axis direction). In other words, the electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12 are arranged such that the planes (yz planes) of their respective rectangles face each other with a predetermined distance between them. The predetermined distance is a distance suitable for electrolysis performed using a pair of the electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12.

[0028] The electrolytic cell-side anode plate 11 comprises an electrolytic cell-side anode plate immersed portion 11a and an electrolytic cell-side anode plate protruding portion 11b. Similarly, the electrolytic cell-side cathode plate 12 comprises an electrolytic cell-side cathode plate immersed portion 12a and an electrolytic cell-side cathode plate protruding portion 12b.

[0029] The electrolytic cell side anode plate 11 and the electrolytic cell side cathode plate 12 are inserted from the outside of the electrolytic cell 10 toward the inside. In FIG. 1, as an example, the electrolytic cell side anode plate 11 and the electrolytic cell side cathode plate 12 are inserted from the side of the electrolytic cell 10 (the xz plane side on the negative side of the y axis) toward the horizontal direction (y axis direction). The electrolytic cell side anode plate immersed portion 11a and the electrolytic cell side cathode plate immersed portion 12a inserted into the electrolytic cell 10 are disposed on the inside side of the electrolytic cell 10, and are entirely immersed in the first aqueous solution L1. In other words, the first aqueous solution L1 is stored in the electrolytic cell 10 so that the electrolytic cell side anode plate immersed portion 11a and the electrolytic cell side cathode plate immersed portion 12a are entirely immersed. 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 z-axis positive side) of the electrode plate immersed portion 11a and the electrolytic cell side cathode plate immersed portion 12a.

[0030] The electrolytic cell-side anode plate protrusion 11b and the electrolytic cell-side cathode plate protrusion 12b are disposed on the external side of the electrolytic cell 10. The wiring 13 and the wiring 14 are lines through which a current flows. The electrolytic cell-side anode plate protrusion 11b is electrically connected to a current control unit 40 via the wiring 13, and the electrolytic cell-side cathode plate protrusion 12b is electrically connected to a current control unit 40 via the wiring 13.

[0031] As the electrolytic cell side anode plate 11 and the electrolytic cell side cathode plate 12, for example, a platinum iridium titanium electrode, a platinum electrode, a ruthenium titanium electrode, an iridium titanium oxide electrode, or the like may be used.

[0032] The inlet 15 is an opening through which air from the space outside the housing B flows in. That is, the inlet 15 is an opening through which air from the space outside the space purification device 1 flows in. In FIG. 1, the inlet 15 is provided on the upper surface (xy plane on the z-axis positive side) of the electrolytic cell 10 as an example, but it is sufficient that the inlet 15 is located above the liquid level S1 of the first aqueous solution L1. The shape of the inlet 15 may be, for example, cylindrical as shown in FIG. 1, or may be a square tube. When the upper surface (the surface on the z-axis positive side) of the electrolytic cell 10 is close to the ceiling surface of the housing B, the inlet 15 may be a hole-shaped opening provided in a part of the upper surface of the electrolytic cell 10. In addition, the inlet 15 and the upper surface (the surface on the z-axis positive side) of the housing B may be formed integrally.

[0033] The mixing space 16 is a space formed on the upper side (z-axis positive side) of the electrolytic cell 10 in a state where the first aqueous solution L1 is stored in the electrolytic cell 10. The mixing space 16 is a space for mixing hypochlorous acid generated by membrane-free electrolysis of the first aqueous solution L1 using a pair of electrolytic cell-side anode plate 11 and electrolytic cell-side cathode plate 12 with air in the external space flowing in from the inlet 15. The hypochlorous acid generated by membrane-free electrolysis includes hypochlorous acid gas that has been volatilized and gasified, and hypochlorous acid dissolved in the first aqueous solution L1. The hypochlorous acid gas is contained in the air that flows in from the inlet 15 and flows out to the external space from the outlet 17 described later. The hypochlorous acid dissolved in the first aqueous solution L1 flows out to the external space from the outlet 17 described later by gas-liquid contact with the air that flows in from the inlet 15.

[0034] The outlet 17 is an opening through which the mixed air, which is a mixture of the air flowing in from the inlet 15 and the hypochlorous acid generated by the membraneless electrolysis of the first aqueous solution L1, flows out to the external space of the housing B. That is, the outlet 17 is an opening through which the mixed air flows out to the external space of the space purification device 1. In FIG. 1, the outlet 17 is provided on the upper surface (xy plane on the z-axis positive side) of the electrolytic cell 10 as an example, similar to the inlet 15, but it may be located above the liquid level of the first aqueous solution L1. The shape of the outlet 17 is similar to that of the inlet 15, and may be, for example, cylindrical as shown in FIG. 1 or square tubular. When the upper surface (the surface on the z-axis positive side) of the electrolytic cell 10 is close to the ceiling surface of the housing B, the outlet 17 may be a hole-shaped opening provided in a part of the upper surface of the electrolytic cell 10. The outlet 17 and the upper surface (the surface on the z-axis positive side) of the housing B may be integrally formed.

[0035] The inlet 15 and the outlet 17 may be provided with a cover (not shown) that can be opened / closed or that can be attached / detached. The cover may be configured to be in a closed state 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. In addition, although the inlet 15 and the outlet 17 are described as having separate configurations, the inlet 15 and the outlet 17 may each serve as both an inlet and an outlet depending on the direction of the wind flowing into the space purification device 1.

[0036] The air containing hypochlorous acid that flows out from the outlet 17 to the space outside the space purification device 1 purifies the space of the outside space. That is, the air containing hypochlorous acid removes bacteria, fungi, viruses, odors, and the like contained in the air in the space outside the housing B.

[0037] The supply tank 20 includes a supply tank side cathode 21, a wiring 22, and an outlet 23. The supply tank side cathode 21 is an electrode used in combination with the electrolytic cell side anode 11 for electrolysis of the second aqueous solution L2. As shown in FIG. 1, an anion exchange membrane 30 is disposed between the electrolytic cell side anode 11 and the supply tank side cathode 21. That is, the electrolysis of the second aqueous solution L2 performed using the pair of the electrolytic cell side anode 11 and the supply tank side cathode 21 is electrolysis with a diaphragm. That is, the electrolytic cell side anode 11 is used for both electrolysis without a diaphragm and electrolysis with a diaphragm. Chloride ions are supplied from the second aqueous solution L2 to the first aqueous solution L1 by the electrolysis with a diaphragm of the second aqueous solution L2 performed using the pair of the electrolytic cell side anode 11 and the supply tank side cathode 21.

[0038] The supply tank side cathode 21 is a supply tank side cathode plate 21 having a plate shape. The plate shape includes a rectangular shape and a rectangular shape. Hereinafter, the supply tank side cathode 21 will also be referred to as a supply tank side cathode plate 21.

[0039] As an example, a case will be described where the supply tank side cathode plate 21 is also rectangular in plate shape, like the electrolytic tank side anode plate 11. As shown in Fig. 1, the supply tank side cathode plate 21 is arranged such that the short side of the rectangle is aligned along the vertical direction (z-axis direction). Moreover, the supply tank side cathode plate 21 is arranged such that the long side of the rectangle is aligned along the horizontal direction (y-axis direction).

[0040] The electrolytic cell side anode plate 11 and the supply cell side cathode plate 21 are each in close proximity to the anion exchange membrane 30. In this specification, "close proximity" includes both a state in which the electrolytic cell side anode plate 11 and the supply cell side cathode plate 21 are close to the anion exchange membrane 30 with a predetermined gap therebetween, and a state in which the electrolytic cell side anode plate 11 and the supply cell side cathode plate 21 are in contact with the anion exchange membrane 30.

[0041] The plane (yz plane on the x-axis positive side) of the rectangular plate on the anion exchange membrane 30 side of the electrolytic cell side anode plate 11 is defined as plane P1. The plane (yz plane on the x-axis negative side) of the rectangular plate on the anion exchange membrane 30 side of the supply cell side cathode plate 21 is defined as plane P2. The planes P1 and P2 are disposed opposite each other via the anion exchange membrane 30. This arrangement allows a uniform electric field to be generated between the electrolytic cell side anode plate 11 and the supply cell side cathode plate 21.

[0042] The electrolytic cell-side anode plate 11 is disposed between the electrolytic cell-side cathode plate 12 and the anion exchange membrane 30. This arrangement makes it possible to keep the potential difference between the electrolytic cell-side anode plate 11 and the electrolytic cell-side cathode plate 12, and the potential difference between the electrolytic cell-side anode plate 11 and the supply cell-side cathode plate 21 small.

[0043] The supply tank side cathode plate 21 includes a supply tank side cathode plate immersed portion 21a and a supply tank side cathode plate protruding portion 21b. The supply tank side cathode plate 21 is inserted from the outside of the electrolytic cell 10 toward the inside. In FIG. 1, as an example, the supply tank side cathode plate 21 is inserted from the side of the electrolytic cell 10 (the xz plane side on the y-axis negative side) toward the horizontal direction (y-axis direction). The supply tank side cathode plate immersed portion 21a inserted into the supply tank 20 is disposed on the inside side of the supply tank 20 and is entirely immersed in the second aqueous solution L2. In other words, the second aqueous solution L2 is stored in the supply tank 20 so that the entire supply tank side cathode plate immersed portion 21a is immersed. That is, the second aqueous solution L2 is stored in the supply tank 20 so that the liquid level S2 of the second aqueous solution L2 exceeds the upper end (the end on the z-axis positive side) of the supply tank side cathode plate immersed portion 21a.

[0044] 1, the supply tank side cathode plate protrusion 21b is disposed on the external side of the supply tank 20. The wiring 22 is a line through which a current flows. The supply tank side cathode plate protrusion 21b is electrically connected to a current control unit 40 via the wiring 22.

[0045] As the supply tank side cathode plate 21, for example, a platinum iridium titanium electrode, a platinum electrode, a ruthenium titanium electrode, an iridium titanium oxide electrode, or the like may be used.

[0046] The outlet 23 is an opening for discharging hydrogen gas generated by the diaphragm electrolysis of the second aqueous solution L2 to the external space of the housing B. The outlet 23 may be, for example, a check valve. When a check valve is used as the outlet 23, hydrogen gas inside the supply tank 20 is discharged to the external space, but the inflow of gas such as air from the external space can be suppressed. When the diaphragm electrolysis of the second aqueous solution L2 is repeated, hydrogen gas accumulates inside the supply tank 20, and the internal pressure of the supply tank 20 increases. The pressure opens the check valve, and hydrogen gas is discharged to the external space of the supply tank 20.

[0047] Fig. 2 is a partial front cross-sectional view showing the space purification device 1 of Fig. 1. In Fig. 2, the case B shown in Fig. 1 is omitted. As shown in Fig. 2, the space purification device 1 may further include a water level detection unit 18 and a water supply unit 19. The water level detection unit 18 detects the position of the liquid level S1 in the first aqueous solution L1. The water level detection unit 18 is, for example, a water level sensor. The water level detection unit 18 is disposed above (on the positive side of the z-axis) the upper ends (parts on the positive side of the z-axis) of at least the electrolytic cell-side anode plate immersed part 11a, the electrolytic cell-side cathode plate immersed part 12a, and the supply cell-side cathode plate immersed part 21a.

[0048] The water supply unit 19 supplies water to the electrolytic cell 10 based on the position of the liquid level S1 detected by the water level detection unit 18. More specifically, the water supply unit 19 supplies water to the electrolytic cell 10 so that the water level does not fall below the upper ends (portions on the z-axis positive side) of the electrolytic cell-side anode plate immersed portion 11a, the electrolytic cell-side cathode plate immersed portion 12a, and the supply cell-side cathode plate immersed portion 21a. The water supply unit 19 may be, for example, a Peltier element that can cool and condense moisture contained in the air into droplets, or a water tank that can store water. The water supply unit 19 may be located at a position where it can supply water to the electrolytic cell 10, and may be located on the upper side, side, or bottom side of the electrolytic cell 10.

[0049] When the spatial purification device 1 includes the water level detection unit 18 and the water supply unit 19, the electrolytic cell-side anode plate immersed portion 11a and the electrolytic cell-side cathode plate immersed portion 12a can be maintained immersed in the first aqueous solution L1. This prevents the electrolytic cell-side anode plate immersed portion 11a and the electrolytic cell-side cathode plate immersed portion 12a from being exposed to air due to a decrease in the first aqueous solution L1, thereby maintaining the electrolysis efficiency of the diaphragm-less electrolysis.

[0050] 2, the spatial purification device 1 according to this embodiment includes a non-diaphragm electrolysis unit E1 and a diaphragm electrolysis unit E2. The current control unit 40 controls a first current flowing through the non-diaphragm electrolysis unit E1 and a second current flowing through the diaphragm electrolysis unit E2, thereby controlling the chemical reaction occurring in the non-diaphragm electrolysis unit E1 and the chemical reaction occurring in the diaphragm electrolysis unit E2.

[0051] The diaphragm-free electrolysis unit E1 is provided in the electrolytic cell 10. The diaphragm-free electrolysis unit E1 produces hypochlorous acid by electrolyzing the first aqueous solution L1 without a diaphragm by passing a first current between the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12. In other words, the diaphragm-free electrolysis unit E1 includes the electrolytic cell-side anode 11 and the electrolytic cell-side cathode 12.

[0052] The membrane-equipped electrolysis unit E2 is provided across the electrolytic cell 10 and the supply cell 20. A second current is passed between the electrolytic cell-side anode 11 and the supply cell-side cathode 21, thereby performing membrane-equipped electrolysis via the anion exchange membrane 30. In other words, the membrane-equipped electrolysis unit E2 includes the electrolytic cell-side anode 11, the supply cell-side cathode 21, and the anion exchange membrane 30.

[0053] Here, we will explain in detail the chemical reaction occurring in the membrane-less electrolysis section E1 provided in the electrolytic cell 10 and the chemical reaction occurring in the membrane-containing electrolysis section E2 provided between the electrolytic cell 10 and the supply cell 20. The following will explain the case where the first aqueous solution L1 containing chloride ions is an aqueous sodium chloride solution and the second aqueous solution L2 is an aqueous magnesium chloride solution.

[0054] [Diaphragmless electrolysis section E1 (electrolytic cell 10)] FIG. 3 is a list of reaction formulas that occur in the membraneless electrolysis section E1. Sodium chloride (NaCl) contained in the sodium chloride aqueous solution is converted into sodium ions (Na + ) and chloride ions (Cl - When a certain voltage is applied to the membrane-less electrolysis section E1, a current flows, electrons move, and the chemical reaction shown in Figure 3 occurs. Reaction diagram 3(a): Electrolyzer anode 11 (chlorine evolution reaction) At the electrolytic cell side anode 11, chloride ions (Cl - ) is an electron (e - ) and chlorine (Cl 2 ) occurs. Reaction diagram 3(b): Cathode 12 on the electrolytic cell side (hydrogen generation reaction) At the electrolytic cell side cathode 12, the water (H 2 O) is an electron (e - ) and hydrogen (H 2 ) and hydroxide ion (OH - ) occurs. Reaction diagram 3(c): Electrolyzer anode 11 (oxygen evolution reaction) At the electrolytic cell side anode 11, the water (H 2 O) to electrons (e - ) is taken away, and oxygen (O2 ) and hydrogen ions (H + ) occurs. Reaction diagram 3(d): Inside the first aqueous solution L1 (hypochlorous acid generation reaction) In the first aqueous solution L1 of the electrolytic cell 10, the chlorine (Cl 2 ) is the water (H 2 O), hydrolysis occurs, producing hydrochloric acid (HCl) and hypochlorous acid (HClO). Hydrochloric acid (HCl) ionizes in an aqueous solution, producing hydrogen ions (H + ) and chloride ions (Cl - ) Figure 3(e): Anion exchange membrane 30 When a voltage is applied to the membrane electrolysis unit E2 and a current flows, the first aqueous solution L1 stored in the electrolysis tank 10 produces electrons (e - ) is lost. - In the first aqueous solution L1, which has lost its charge, a force that maintains electrical neutrality acts, and negatively charged chloride ions (Cl - ) is supplied from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10 through the anion exchange membrane 30. In the first aqueous solution L1, the electrons (e - ) changes to chloride ions (Cl - ) can be said to be the case. Reaction diagram 3(f): Hypochlorous acid generation reaction (equilibrium reaction equation) 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. - To prevent the apparent increase or decrease, the current control described below is performed. Equation 3(g): Chloride ion transformation during electrolysis The chlorine (Cl) produced by reaction 3(a) 2 ) is converted to hydrochloric acid (HCl) and hypochlorous acid (HClO) according to reaction scheme 3(d), which can be expressed in a single equation as scheme 3(g).

[0055] FIG. 4 shows a reaction formula including the ratio of the current flowing through the electrolysis unit without a diaphragm E1 to the current flowing through the electrolysis unit with a diaphragm E2. Here, the ratio of the current flowing through the electrolysis cell side anode 11 used for the chlorine generation reaction in Reaction Formula 3(a) is denoted as "x", and the ratio of the current used for the oxygen generation reaction in Reaction Formula 3(c) is denoted as "1-x". In addition, the ratio of the current flowing through the electrolysis cell side anode 11 originating from the electrolysis unit without a diaphragm E1 is denoted as "y", and the ratio of the current originating from the electrolysis unit with a diaphragm E2 is denoted as "1-y". Applying the above x and y to Reaction Formula 3(b)+(c)+(g) and taking into account the change shown in FIG. 3(e) results in Reaction Formula 4(a).

[0056] When membrane-free electrolysis is performed in the membrane-free electrolysis section E1, the chloride ions in the electrolytic cell 10 are consumed and therefore reduced, but in the space purification device 1 of this embodiment, chloride ions are supplied from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic cell 10.

[0057] Here, the amount of chloride ions (Cl) consumed by the membrane-free electrolysis is transferred from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10. - ) is supplied, In the electrolytic cell 10, chloride ions (Cl - The conditions under which the apparent increase or decrease 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 scheme 4(b): Cl - This shows the conditions under which there is no apparent increase or decrease. · Reaction diagram 4(c): Shows the condition equation for coefficients x and y transformed from reaction diagram 4(b). · Reaction Scheme 4(d): Substituting Reaction Scheme 4(c) into Reaction Scheme 4(a) gives Reaction Scheme 4(d). Reaction Scheme 4(e): A variation of Reaction Scheme 4(d) is shown.

[0058] From reaction formula 4(e), for example, when two electrons flow to the non-diaphragm electrolysis section E1, one hypochlorous acid (HClO) is generated. For example, when four electrons flow to the non-diaphragm electrolysis section E1, one oxygen is generated. For example, when two electrons flow to the non-diaphragm electrolysis section E1, one hydrogen is generated.

[0059] In addition, since the acid dissociation constant of hypochlorous acid (HClO) is approximately 7.5, it is necessary to maintain the pH of the first aqueous solution L1 unchanged. In reaction formula FIG. 4(e), the hydroxide ions and hydrogen ions, which are the cause of the change in pH, react to form water and disappear from the reaction formula. Therefore, the amount of chloride ions (Cl 2 ) consumed by the membraneless electrolysis is transferred from the second aqueous solution L2 stored in the supply tank 20 to the first aqueous solution L1 stored in the electrolytic tank 10. - ) is supplied to the electrolytic cell 10, and Cl - When the condition is such that there is no apparent increase or decrease in pH, the increase or decrease in pH can also be suppressed.

[0060] When the number of electrons flowing to the membraneless electrolysis section E1 changes as described above, 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 supply amount of chloride ions supplied from the supply tank 20 to the electrolysis tank 10 changes. For example, when the ratio of the current used for membraneless electrolysis changes from the supply tank 20 to the chloride ion (Cl - ) is supplied to the electrolytic cell 10. - When the current ratio is greater than the condition where the current does not increase or decrease (reaction formula 4(f)), the Cl - The supply of Cl in the electrolytic cell 10 decreases. - decreases.

[0061] Cl in electrolytic cell 10 - When the electrolysis efficiency is reduced, the electrolysis efficiency of the membrane-free electrolysis is reduced. If the membrane-free electrolysis is continued in a state where the electrolysis efficiency is reduced, the Cl in the electrolytic cell 10 gradually - increases, and Cl in the electrolytic cell 10 - reaches a level that appears to be no longer increasing or decreasing.

[0062] On the other hand, the current used for the membraneless electrolysis is such that chloride ions (Cl - ) is supplied to the electrolytic cell 10. - When the current amount is larger than the condition under which the apparent increase or decrease does not occur (see reaction formula 4(g) below), the Cl supplied from the supply tank 20 to the electrolytic tank 10 - The supply of Cl in the electrolytic cell 10 increases. - increases.

[0063] The chloride ions (Cl - ) increases, the electrolysis efficiency of the membrane-free electrolysis increases. If membrane-free electrolysis is continued in a state where the electrolysis efficiency has increased, the Cl in the electrolytic cell 10 gradually increases. - decreases, and Cl in the electrolytic cell 10 - reaches a level that appears to be no longer increasing or decreasing.

[0064] In addition, Cl in the electrolytic cell 10 - When the amount of Cl in the electrolytic cell 10 increases, the equilibrium in the reaction diagram 3(f) shifts to the left, and the amount of chlorine generated increases. - By adjusting the current passed through the membraneless electrolysis unit E1 and the current passed through the membrane-containing electrolysis unit E2 so that the apparent increase or decrease in current does not occur, hypochlorous acid can be produced while suppressing the generation of chlorine.

[0065] [Diaphragm electrolysis part E2] FIG. 5 is a list of reaction formulas occurring in the membrane electrolysis section E2. The reactions in the second aqueous solution L2 in the supply tank 20 will be described. The electrodes arranged in the supply tank 20 are There is only the cathode 21. When a predetermined voltage is applied to the membrane-containing electrolysis section E2, a current flows, electrons move, and the chemical reaction shown in FIG. Reaction diagram 5(a): Cathode 12 on the electrolytic cell side (hydrogen generation reaction) At the supply tank side cathode 21, the water (H 2 O) is an electron (e - ) and hydrogen (H 2 ) and hydroxide ion (OH - ) is produced. Hydrogen evaporates as a gas, and the hydroxide ions are used in Reaction Scheme 5(c) below.

[0066] Figure 5(b): Anion exchange membrane 30 When a voltage is applied to the membrane electrolysis unit E2 and a current flows, the chloride ions (Cl - ) permeates through the anion exchange membrane 30 and is supplied to the first aqueous solution L1, and the second aqueous solution L2 is supplied with electrons (e - In other words, in the second aqueous solution L2, the chloride ions (Cl - ) changes to electron (e - ) can be said to be the case.

[0067] Reaction diagram 5(c): Second aqueous solution L2 (magnesium hydroxide precipitation reaction) The magnesium ions (Mg 2+ ) and the hydroxide ion (OH - ) reacts with magnesium hydroxide (Mg(OH) 2 ) precipitate is formed. Magnesium hydroxide (Mg(OH) 2 ) solubility product is Ksp = 1.2 × 10 -11 (mol / L) 3 It is a substance that is extremely difficult to dissolve in aqueous solutions with a neutral to alkaline pH. For example, magnesium hydroxide is soluble in a weakly alkaline aqueous solution with a pH of 10 at only 1.2 × 10 -3 In the second aqueous solution L2 of the supply tank 20, hydroxide ions (OH - ) is used to generate magnesium hydroxide precipitate, and hydroxide ions (OH - ) and thus the increase in pH of the second aqueous solution L2 can be suppressed.

[0068] Furthermore, when a magnesium chloride aqueous solution is used as the second aqueous solution L2, the pH of the magnesium hydroxide saturated aqueous solution in which magnesium hydroxide is saturated, which is generated after the electrolysis with a diaphragm, is pH 10.36 calculated from the solubility product. Therefore, even after performing electrolysis with a diaphragm for 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, that is, pH 11 or more. Therefore, a space purification device that prevents the second aqueous solution L2 from becoming strongly alkaline and has improved safety can be provided.

[0069] Also, for example, a contractor may install the space purification device 1 according to the present embodiment. After using 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 using a sodium chloride aqueous solution as the second aqueous solution L2.

[0070] The above is the details of the chemical reaction occurring in the membrane-less electrolysis section E1 provided in the electrolytic cell 10 and the chemical reaction occurring in the membrane-containing electrolysis section E2 provided between the electrolytic cell 10 and the supply cell 20.

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

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

[0073] The voltage acquiring unit 41 acquires a voltage between the electrolytic cell side anode 11 and the electrolytic cell side cathode 12. The voltage acquiring unit 41 is, for example, a voltmeter. The calculation unit 42 calculates the conductivity of the first aqueous solution L1 based on the voltage acquired by the voltage acquiring unit 41. The estimation unit 43 estimates the chloride ion concentration of the first aqueous solution L1 based on the conductivity of the first aqueous solution L1 calculated by the calculation unit 42.

[0074] The current control unit 40 controls the first current passed through the non-diaphragm electrolysis unit E1 and the second current passed through the diaphragm electrolysis unit E2 shown in Fig. 6 so as to maintain the chloride ion concentration in the first aqueous solution L1 at a predetermined concentration. Three examples of current control by the current control unit 40 will be described below.

[0075] [1. When the first and second currents flow simultaneously] When the current control unit 40 causes the first current and the second current to flow simultaneously, it performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is lower than a predetermined concentration: the current ratio of the first current and the second current is changed so as to increase the amount of chloride ions supplied from the second aqueous solution L2 to the first aqueous solution L1 through the anion exchange membrane 30. More specifically, the current ratio of the first current is decreased and the current ratio of the second current is increased. (2) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is higher than a predetermined concentration: the current ratio of the first current and the second current is changed so as to reduce the amount of chloride ions supplied from the second aqueous solution L2 to the first aqueous solution L1 through the anion exchange membrane 30. More specifically, the current ratio of the first current is increased and the current ratio of the second current is decreased. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is a predetermined concentration: the current ratio of the first current to the second current is not changed.

[0076] [2. When the first current flows at a specified value and the second current is controlled at the same time] When the current control unit 40 controls the second current while causing the first current to flow at a predetermined value, the current control unit 40 performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is lower than a predetermined concentration: a second current is passed so as to increase the amount of chloride ions that permeate from the second aqueous solution L2 through the anion exchange membrane 30 and are supplied to the first aqueous solution L1. (2) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is higher than a predetermined concentration: the second current is stopped so that the supply of chloride ions from the 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 43 is a predetermined concentration: the first current and the second current are not changed.

[0077] [3. When the first or second current flows] When the current control unit 40 causes the first current or the second current to flow, it performs the following controls (1) to (3). (1) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is lower than a predetermined concentration: the first current is stopped and the second current is simultaneously passed so as to increase the amount of chloride ions that permeate from the second aqueous solution L2 through the anion exchange membrane 30 and are supplied to the first aqueous solution L1. (2) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is higher than a predetermined concentration: the second current is stopped and the first current is simultaneously passed so as to stop the supply of chloride ions from the second aqueous solution L2 to the first aqueous solution L1. (3) When the chloride ion concentration of the first aqueous solution L1 estimated by the estimation unit 43 is a predetermined concentration: The first and second currents are not changed.

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

[0079] In the above "1. When the first current and the second current are passed simultaneously," if there is an increase or decrease in the chloride ion concentration in the first aqueous solution L1, the current ratio between the first current and the second current is changed. Since the first current and the second current are passed simultaneously, the increase or decrease in the chloride ion concentration in the first aqueous solution L1 is minimized, and it is possible to maintain the concentration at an optimal predetermined level.

[0080] In the above-mentioned "2. When the first current is passed at a predetermined value and the second current is controlled at the same time," when there is an increase or decrease in the chloride ion concentration of the first aqueous solution L1, mainly the second current is passed or stopped. In the above-mentioned "3. When the first current or the second current is passed," when there is an increase or decrease in the chloride ion concentration of the first aqueous solution L1, one of the first current and the second current is passed and the other is stopped. Therefore, the chloride ion concentration of the first aqueous solution L1 can be maintained at a predetermined concentration. In the above-mentioned 2 and 3, it is only necessary to control either the first current or the second current, so that the current can be easily controlled.

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

[0082] Note that a plurality of current control units 40 may be provided to control the first current and the second current separately.

[0083] In FIG. 2, the inlet 15 and the outlet 17 are arranged on the front left side (negative side of the y-axis and negative side of the x-axis) and the back right side (positive side of the y-axis and positive side of the x-axis) when the electrolytic cell 10 is viewed in plan, but the arrangement is not limited to this. For example, the positions of the inlet 15 and the outlet 17 may be reversed, the inlet 15 and the outlet 17 may be at the same position on the x-axis, or the inlet 15 and the outlet 17 may be at the same position on the y-axis. However, when the inlet 15 and the outlet 17 are arranged, it is preferable to arrange them so that they are at the farthest positions on the xy plane. With such an arrangement, the time during which the inflowing air and hypochlorous acid are mixed in the mixing space 16 is longer, so that more hypochlorous acid can be contained in the mixed air.

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

[0085] When the current distribution between the electrolytic cell side anode plate 11 and the supply cell side cathode plate 21 becomes uneven, areas of high and low current density are generated. In the areas of high current density, deterioration of the catalytic layer on the surfaces of the electrolytic cell side anode plate 11 and the supply cell side cathode plate 21 (hereinafter also referred to as each electrode plate) is likely to progress, while in areas of low current density, deterioration of the catalytic layer on the surface of each electrode plate is unlikely to progress. In other words, when an uneven electric field occurs between the electrolytic cell side anode plate 11 and the supply cell side cathode plate 21, the distribution of current becomes uneven, and areas of different current densities may exist simultaneously on the same electrode plate. Therefore, deterioration of the catalytic layer due to use of each electrode plate may occur unevenly. The degree of deterioration of the catalytic layer on the surface of each electrode plate may differ. When electrolysis is repeated, there may be areas on each electrode plate that can be used as an electrode and areas that have deteriorated and become unusable at the same time. When electrolysis is performed on each electrode plate that includes areas that cannot be used as an electrode, there is a risk that the electrolysis efficiency may be easily reduced.

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

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

[0088] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention.

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

[0090] (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 that of the first aqueous solution and supplying chloride ions to the first aqueous solution; an electrolytic cell-side anode and an electrolytic cell-side cathode provided in the electrolytic cell; A supply tank side cathode provided in the supply tank; an anion exchange membrane that connects the electrolytic cell and the supply cell so as to be permeable to anions based on a voltage applied between the electrolytic cell-side anode and the supply cell-side cathode; a membrane-free electrolysis unit provided in the electrolytic cell, which generates hypochlorous acid by performing membrane-free electrolysis of the first aqueous solution by passing a first current between the electrolytic cell-side anode and the electrolytic cell-side cathode; a membrane-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, the second aqueous solution is a metal chloride aqueous solution containing metal ions and the chloride ions, By carrying out the diaphragm electrolysis, The chloride ions contained in the second aqueous solution stored in the supply tank are supplied to the anion so as to replenish the chloride ions contained in the first aqueous solution that have been reduced by the membrane-free electrolysis. permeating the ion exchange membrane and supplying the first aqueous solution stored in the electrolytic cell; In the supply tank, the metal ions contained in the second aqueous solution are reacted with the hydroxide ions generated by the diaphragm electrolysis to form a precipitate of a metal hydroxide. Space purification device. (Item 2) The second aqueous solution is an aqueous magnesium chloride solution. Item 1. The spatial purification device according to item 1. (Item 3) a current control unit that controls the second current so as to replenish chloride ions contained in the first aqueous solution that have been reduced by the membrane-free 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 applies the first current and the second current at a predetermined ratio, thereby maintaining the chloride ion concentration of the first aqueous solution at a predetermined concentration. Item 1. The spatial purification device according to item 1. (Item 4) The current control unit is 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 electrical conductivity calculated by the calculation unit, The current control unit is The first current and the second current are caused to flow simultaneously; When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, a current ratio of the first current and the second current is changed so that an amount of chloride ions permeating from the second aqueous solution through the anion exchange membrane and supplied to the first aqueous solution is increased; When the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, a current ratio between the first current and the second current is changed so that an amount of chloride ions permeating from the second aqueous solution through the anion exchange membrane and supplied to the first aqueous solution is reduced. Item 3. The spatial purification device according to item 3. (Item 5) When the chloride ion concentration of the first aqueous solution is the predetermined concentration, the current ratio of the first current and the second current is not changed. Item 4. The spatial purification device according to item 4. (Item 6) 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 electrical conductivity calculated by the calculation unit, The current control unit is The first current is caused to flow at a predetermined value while the second current is controlled; The control of the second current includes: When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, the second current is applied so as to increase the amount of chloride ions permeating from the second aqueous solution through the anion exchange membrane and being supplied to the first aqueous solution; When the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, the second current is stopped so that the supply of chloride ions from the second aqueous solution to the first aqueous solution is stopped. Item 3. The spatial purification device according to item 3. (Item 7) 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 electrical conductivity calculated by the calculation unit, The current control unit is When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, the first current is stopped and the second current is simultaneously applied so that an amount of chloride ions permeating from the second aqueous solution through the anion exchange membrane and supplied to the first aqueous solution is increased; When the chloride ion concentration of the first aqueous solution is higher than a predetermined concentration, stopping the second current and simultaneously applying the first current so as to stop the supply of chloride ions from the second aqueous solution to the first aqueous solution; Item 3. The spatial purification device according to item 3. (Item 8) the electrolytic cell-side anode, the electrolytic cell-side cathode, and the supply cell-side cathode are, respectively, an electrolytic cell-side anode plate, an electrolytic cell-side cathode plate, and a supply cell-side cathode plate each having a plate-like shape; the electrolytic cell-side anode plate and the electrolytic cell-side cathode plate are inserted into the electrolytic cell from outside the electrolytic cell, and the supply cell-side cathode plate is inserted into the supply cell from outside the supply cell, The electrolytic cell-side anode plate includes an electrolytic cell-side anode plate immersion portion arranged on the inside side of the electrolytic cell, and an electrolytic cell-side anode plate protrusion portion arranged on the outside side of the electrolytic cell, the electrolytic cell-side cathode plate includes an electrolytic cell-side cathode plate immersion portion arranged on the inside of the electrolytic cell, and an electrolytic cell-side cathode plate protrusion portion arranged on the outside of the electrolytic cell, The supply tank side cathode plate includes a supply tank side cathode plate immersion portion arranged on the inside side of the supply tank and a supply tank side cathode plate protrusion portion arranged on the outside side of the supply tank, The entire anode plate immersed portion on the electrolytic cell side and the cathode plate immersed portion on the electrolytic cell side are Immersed in the first aqueous solution, The entire supply tank side cathode plate immersion portion is Immersed in the second aqueous solution; Item 1. The spatial purification device according to item 1. (Item 9) a water level detector for detecting a liquid level of the first aqueous solution; a water supply unit that supplies water to the electrolytic cell so that the liquid level detected by the water level detection unit does not fall below an upper end of the electrolytic cell-side anode plate immersion portion and the electrolytic cell-side cathode plate immersion portion. Item 9. The spatial purification device according to item 7 or 8. (Item 10) The non-diaphragm electrolysis unit is The electrolytic cell side anode; The electrolytic cell-side cathode, The membrane electrolysis unit includes: The electrolytic cell side anode; The supply tank side cathode; The anion exchange membrane, Item 1. The spatial 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; and an outlet through which the mixed air flows out to the exterior space. Item 1. The spatial purification device according to item 1. [Explanation of symbols]

[0091] 1. Space Purification Device 10 Electrolytic cell 11 Electrolyzer side anode 11a Electrolytic tank side anode plate immersion part 11b Electrolytic tank side anode plate protrusion 12 Electrolytic cell side cathode 12a Electrolytic tank side cathode plate immersion part 12b Electrolytic cell side cathode plate protrusion 13 Wiring 14 Wiring 15 Inlet 16 Mixed space 17 Outlet 18 Water level detector 19 Water supply section 20 Supply tank 21 Supply tank side cathode 21a Supply tank side cathode plate immersion part 21b Supply tank side cathode plate protrusion 22 Wiring 23 Outlet 30 Anion exchange membrane 40 Current control section 41 Voltage acquisition unit 42 Calculation section 43 Estimation part B-Case L1 1st aqueous solution L2 2nd 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 that of the first aqueous solution and supplying chloride ions to the first aqueous solution; an electrolytic cell-side anode and an electrolytic cell-side cathode provided in the electrolytic cell; A supply tank side cathode provided in the supply tank; an anion exchange membrane that connects the electrolytic cell and the supply cell so as to be permeable to anions based on a voltage applied between the electrolytic cell-side anode and the supply cell-side cathode; a membrane-free electrolysis unit provided in the electrolytic cell, which generates hypochlorous acid by performing membrane-free electrolysis of the first aqueous solution by passing a first current between the electrolytic cell-side anode and the electrolytic cell-side cathode; a diaphragm electrolysis unit provided between the electrolytic cell and the supply cell, which performs membrane electrolysis via the anion exchange membrane by passing a second current between the electrolytic cell side anode and the supply cell side cathode, the second aqueous solution is a metal chloride aqueous solution containing metal ions and the chloride ions, By carrying out 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 reduced by the membrane-free electrolysis; In the supply tank, the metal ions contained in the second aqueous solution are reacted with the hydroxide ions generated by the diaphragm electrolysis to form a precipitate of a metal hydroxide. Space purification device.

2. The second aqueous solution is an aqueous magnesium chloride solution. The space purification device according to claim 1 .

3. a current control unit that controls the second current so as to replenish chloride ions contained in the first aqueous solution that have been reduced by the membrane-free 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 applies the first current and the second current at a predetermined ratio, thereby maintaining a chloride ion concentration of the first aqueous solution at a predetermined concentration. The space purification device according to claim 1 .

4. The current control unit is 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 electrical conductivity calculated by the calculation unit, The current control unit is The first current and the second current are caused to flow simultaneously; When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, a current ratio of the first current and the second current is changed so that an amount of chloride ions permeating from the second aqueous solution through the anion exchange membrane and supplied to the first aqueous solution is increased; When the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, a current ratio of the first current and the second current is changed so that an amount of chloride ions permeating from the second aqueous solution through the anion exchange membrane and supplied to the first aqueous solution is reduced. The space purification device according to claim 3.

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

6. 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 electrical conductivity calculated by the calculation unit, The current control unit is The first current is caused to flow at a predetermined value while the second current is controlled; The control of the second current includes: When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, the second current is applied so as to increase the amount of chloride ions permeating from the second aqueous solution through the anion exchange membrane and being supplied to the first aqueous solution; When the chloride ion concentration of the first aqueous solution is higher than the predetermined concentration, the second current is stopped so that the supply of chloride ions from the second aqueous solution to the first aqueous solution is stopped. The space purification device according to claim 3.

7. 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 electrical conductivity calculated by the calculation unit, The current control unit is When the chloride ion concentration of the first aqueous solution is lower than a predetermined concentration, the first current is stopped and the second current is simultaneously supplied so that an amount of chloride ions permeating the anion exchange membrane from the second aqueous solution and being supplied to the first aqueous solution is increased; When the chloride ion concentration of the first aqueous solution is higher than a predetermined concentration, stopping the second current and simultaneously supplying the first current so as to stop the supply of chloride ions from the second aqueous solution to the first aqueous solution; The space purification device according to claim 3.

8. the electrolytic cell-side anode, the electrolytic cell-side cathode, and the supply cell-side cathode are, respectively, an electrolytic cell-side anode plate, an electrolytic cell-side cathode plate, and a supply cell-side cathode plate each having a plate-like shape; the electrolytic cell-side anode plate and the electrolytic cell-side cathode plate are inserted into the electrolytic cell from outside the electrolytic cell, and the supply cell-side cathode plate is inserted into the supply cell from outside the supply cell, The electrolytic cell-side anode plate includes an electrolytic cell-side anode plate immersion portion arranged on the inside side of the electrolytic cell, and an electrolytic cell-side anode plate protrusion portion arranged on the outside side of the electrolytic cell, the electrolytic cell-side cathode plate includes an electrolytic cell-side cathode plate immersion portion arranged on the inside of the electrolytic cell, and an electrolytic cell-side cathode plate protrusion portion arranged on the outside of the electrolytic cell, The supply tank side cathode plate includes a supply tank side cathode plate immersion portion arranged on the inside side of the supply tank and a supply tank side cathode plate protrusion portion arranged on the outside side of the supply tank, The entire anode plate immersed portion on the electrolytic cell side and the cathode plate immersed portion on the electrolytic cell side are Immersed in the first aqueous solution; The entire supply tank side cathode plate immersion portion is Immersed in the second aqueous solution; The space purification device according to claim 1 .

9. a water level detector for detecting a liquid level of the first aqueous solution; a water supply unit that supplies water to the electrolytic cell so that the liquid level detected by the water level detection unit does not fall below an upper end of the electrolytic cell-side anode plate immersion portion and the electrolytic cell-side cathode plate immersion portion. The space purification device according to claim 7 or 8.

10. The non-diaphragm electrolysis unit is The electrolytic cell side anode; The electrolytic cell-side cathode, The membrane electrolysis unit includes: 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; and 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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