JP2022048865A - Electrolytic cell and ozone water dispersing device - Google Patents

Abstract

To provide an electrolytic cell capable of efficiently producing ozone water, and an ozone water dispersing device.SOLUTION: An electrolytic cell 4 produces ozone water OW from raw water RW. The electrolytic cell 4 comprises: an anode 31; an ion exchange membrane 32 configured to be adjacent to the anode 31; a first cathode 33 disposed across the ion exchange membrane 32 from the anode 31; a second cathode 34 disposed between the ion exchange membrane 32 and the first cathode 33 and having ion exchange performance; and a housing 15 accommodating them. The housing 15 comprises: a water inlet 15a for taking in the raw water RW; and a water outlet 15b for draining the ozone water OW.SELECTED DRAWING: Figure 2

Description

The present invention relates to an electrolytic cell that produces ozone water, and an ozone water spraying device using the same.

The electrolytic cell disclosed in Patent Document 1 below has an anode, a cathode, and an ion exchange membrane. Ozone water is generated by passing raw water through the inside of the electrolytic cell while a voltage is applied between the anode and the cathode. Specifically, ozone is generated by electrolysis of the raw material water, and the generated ozone is dissolved in the raw material water to obtain ozone water.

Japanese Patent No. 6249200

When tap water or the like containing a large amount of mineral components as compared with deionized water is used as the raw material water, the mineral components are precipitated as a salt between the cathode and the ion exchange membrane in the electrolytic cell of Patent Document 1. Therefore, the efficiency of ozone water generation may decrease.
The present invention has been made under such a background, and an object of the present invention is to provide an electrolytic cell and an ozone water spraying device capable of efficiently generating ozone water.

The present invention is an electrolytic cell that generates ozone water from raw material water, and has a housing having a water intake port for taking in raw material water and a water discharge port for discharging ozone water, and an anode arranged in the housing. An ion exchange film arranged adjacent to the anode in the housing, a first cathode arranged in the housing on the opposite side of the anode with the ion exchange film interposed therebetween, and the ion exchange film. And an electrolytic cell which is arranged between the first cathodes and includes a second cathode having ion exchange performance.

The present invention is characterized in that the second cathode includes a carbon cathode made of carbon fibers and a coating member having ion exchange performance and covering the carbon fibers.
In the present invention, the carbon cathode includes a cathode side portion adjacent to the first cathode and an exchange membrane side portion adjacent to the ion exchange membrane, and the coating member comprises the carbon fiber in the cathode side portion. It is characterized by including a low-hydrophilic coating member to be coated and a high-hydrophilic coating member which is coated with the carbon fiber on the exchange membrane side portion and has higher hydrophilicity than the low-hydrophilic coating member.

The present invention is characterized in that the carbon cathode is composed of a plurality of sheet members.
The present invention is characterized in that the voltage applied to the second cathode is lower than the voltage applied to the first cathode.
In the present invention, the electrolytic cell, a storage unit for storing raw water, a spraying unit for spraying ozone water generated by the electrolytic cell, and the electrolytic cell are directed from the storage unit to the spraying unit. It is an ozone water spraying device including a water supply unit that feeds water.

According to the present invention, in this electrolytic cell, ozone water is generated from the raw material water taken into the housing from the water intake port, and the generated ozone water is discharged from the water discharge port. Since the first cathode is arranged in the housing on the side opposite to the anode with the ion exchange membrane interposed therebetween, the raw material water is electrolyzed in the housing and ozone is generated. In this electrolytic cell, a second cathode having ion exchange performance is arranged between the ion exchange membrane and the first cathode. Therefore, the mineral component in the raw material water does not precipitate as a salt between the ion exchange membrane and the first cathode, but moves in the ion state along the surface of the second cathode to the first cathode side. Finally, the mineral component is deposited on the portion of the first cathode opposite to the ion exchange membrane. Since it is possible to suppress the precipitation of mineral components between the ion exchange membrane and the first cathode, ozone water can be efficiently generated.

In particular, ozone water can be efficiently generated even when tap water or the like containing a large amount of mineral components as a raw material water is used as compared with deionized water or the like.
According to the present invention, the second cathode includes a carbon cathode and a coating member. Since the carbon cathode is made of carbon fiber, its surface area is larger than that of a plate-shaped metal. Since the carbon fiber is coated with the coating member having the ion exchange performance, the ion exchange performance of the second cathode can be improved. Therefore, it is possible to promote the movement of the mineral component in the raw material water to the first cathode side. That is, the precipitation of mineral components between the ion exchange membrane and the first cathode can be further suppressed.

According to the present invention, the hydrophilicity of the exchange membrane side portion adjacent to the ion exchange membrane in the carbon cathode is higher than the hydrophilicity of the first cathode side portion adjacent to the first cathode in the carbon cathode. Therefore, the precipitation of mineral components on the ion exchange membrane side can be further suppressed.
According to the present invention, the carbon cathode is composed of a plurality of sheet members. Therefore, the coating member can be changed for each sheet member. This makes it possible to select a coating suitable for suppressing the precipitation of mineral components between the ion exchange membrane and the first cathode for each sheet member.

According to the present invention, the voltage applied to the second cathode is lower than the voltage applied to the first cathode. Therefore, the ionic mineral component in the vicinity of the second cathode is likely to be attracted to the first cathode side. Therefore, it is possible to promote the movement of the mineral component in the raw material water to the first cathode side. That is, the precipitation of mineral components between the ion exchange membrane and the first cathode can be further suppressed.
According to the present invention, the raw material water stored in the storage section is sent to the electrolytic cell by the water supply section. The raw material water sent to the electrolytic cell is electrolyzed by the electrolytic cell to generate ozone water. Then, the ozone water generated by the electrolytic cell is sent to the spraying section by the water feeding section, and is sprayed from the spraying section toward the outside of the ozone water spraying device.

FIG. 1 is a vertical sectional view of an ozone water spray provided with an electrolytic cell according to the present invention. FIG. 2 is an exploded perspective view of the electrolytic cell. FIG. 3 is a cross-sectional view of the electrolytic cell. FIG. 4 is a schematic diagram for explaining the configuration of the second cathode provided in the electrolytic cell. FIG. 5A is an image for explaining the result of the precipitation amount comparison experiment when an electrolytic cell having ion exchange performance is used, and is an enlarged image of the surface of the ion exchange membrane before washing with hydrochloric acid. FIG. 5B is an image for explaining the result of the precipitation amount comparison experiment when an electrolytic cell having no ion exchange performance is used, and is an enlarged image of the surface of the ion exchange membrane before washing with hydrochloric acid. FIG. 5C is an image for explaining the result of the precipitation amount comparison experiment when an electrolytic cell having ion exchange performance is used, and is an enlarged image of the surface of the ion exchange membrane after washing with hydrochloric acid. FIG. 5D is an image for explaining the result of the precipitation amount comparison experiment when an electrolytic cell having no ion exchange performance is used, and is an enlarged image of the surface of the ion exchange membrane after washing with hydrochloric acid.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
<Composition of ozone water spray>
FIG. 1 is a vertical sectional view of an ozone water spray 1 as an ozone water spraying device according to the present invention. With reference to FIG. 1, the ozone water spray 1 includes a housing 2, a storage unit 3, an electrolytic cell 4, a water supply unit 5, a spraying unit 6, and a power supply unit 7.

The housing 2 houses a storage unit 3, an electrolytic cell 4, a water supply unit 5, a spraying unit 6, and a power supply unit 7. The storage unit 3 stores the raw material water RW. The electrolytic cell 4 electrolyzes the raw material water RW to generate ozone water. The spraying unit 6 sprays the ozone water OW generated by the electrolytic cell 4 toward the outside. The water supply unit 5 supplies water from the storage unit 3 to the spray unit 6 via the electrolytic cell 4. The electric power supply unit 7 supplies electric power to each member of the ozone water spray 1.

The ozone water spray 1 generates ozone water OW from the raw material water RW and sprays the generated ozone water OW based on the user's operation on an operation unit (not shown) such as a switch or a lever.
The housing 2 is composed of a body portion 10, a neck portion 11, and a head portion 12. The body portion 10 has a tapered shape that tapers upward from a flat bottom portion. The neck portion 11 has a substantially cylindrical shape extending in the vertical direction. The head 12 has a substantially rectangular cylinder extending so as to intersect with respect to the neck 11.

The storage portion 3 is a container housed in the body portion 10 of the housing 2. Examples of the raw material water RW stored in the storage unit 3 include pure water and tap water.
The electrolytic cell 4 is arranged in the storage unit 3 in the vicinity of the bottom portion of the storage unit 3. As will be described in detail later, the electrolytic cell 4 includes the housing 15 and electrolyzes the raw material water RW taken into the internal space 16 of the housing 15 to generate ozone water OW. The housing 15 has a water intake port 15a for taking raw water RW into the internal space 16, a water discharge port 15b for discharging ozone water OW from the internal space 16, and hydrogen (H ₂ ) generated when ozone water OW is generated. It has a hydrogen discharge port 15c for discharging water.

The spraying unit 6 includes a shower nozzle 17 for spraying the shower-shaped ozone water OW and a mist nozzle 18 for spraying the mist-shaped ozone water OW. The shower nozzle 17 is arranged at one end of the head 12 of the housing 2, and the mist nozzle 18 is arranged at the other end of the head 12 of the housing 2.
The water supply unit 5 sends the raw water RW in the storage unit 3 to the water intake port 15a of the electrolytic cell 4 from the first water supply pipe 19, and the ozone water OW generated by the electrolytic cell 4 from the discharge port 16b of the electrolytic cell 4. It includes a second water supply pipe 20 that feeds into the spraying unit 6, and a pump 21 that discharges water from the storage unit 3 toward the spraying unit 6 via the first water supply pipe 19, the electrolytic cell 4, and the second water supply pipe 20. ..

The pump 21 is, for example, a diaphragm-driven small pump. The pump 21 is interposed in the first water pipe 19. The pump 21 has a pump main body 22, a water suction port 21a for sucking the raw material water RW into the pump main body 22, and a water discharge port 21b for discharging the raw material water RW in the pump main body 22. The first water pipe 19 includes a water suction pipe 23 having one end connected to the water suction port 21a and a water discharge pipe 24 having one end connected to the water discharge port 21b. The other end of the water absorption pipe 23 is located in the storage portion 3 on the bottom side of the water surface WS of the raw material water RW. The other end of the water discharge pipe 24 is connected to the water intake port 15a of the housing 15 of the electrolytic cell 4.

The pump 21 is switched to either a drive state or a stop state by the operation of the operation unit by the user. The spraying mode of the spraying unit 6 is switched between a shower mode in which ozone water OW is sprayed from the shower nozzle 17 and a mist mode in which ozone water OW is sprayed from the mist nozzle 18 by the operation of the operation unit by the user.
The power supply unit 7 includes a power source 25 such as a battery arranged below the storage unit 3 in the body portion 10 of the housing 2, and a plurality of wirings 26 extending from the power supply 25 toward the electrolytic cell 4. Although not shown, the power supply unit 7 may include wiring for supplying electric power to the pump 21 and the operation unit.

By driving the pump 21, the raw material water RW in the storage unit 3 is supplied to the electrolytic cell 4 via the first water pipe 19. The raw water RW changes to ozone water OW as it passes through the electrolytic cell 4. The ozone water OW generated in the electrolytic cell 4 is supplied to the spraying section 6 via the second water pipe 20. As a result, the ozone water OW is discharged from the spraying unit 6. FIG. 1 shows a state in which the shower nozzle 17 sprays ozone water OW.

FIG. 2 is an exploded perspective view of the electrolytic cell 4. The electrolytic cell 4 is a separable type and has a substantially columnar shape as a whole.
With reference to FIG. 2, the electrolytic cell 4 has a housing 15, an anode energization terminal 30, an anode 31, an ion exchange membrane 32, a first cathode 33, a second cathode 34, a first cathode energization terminal 35, and a second cathode energization terminal. 36 and the elastic member 37 are included.

The housing 15 has a first holder 40 and a second holder 50. The first holder 40 has a bottomed tubular shape. The first holder 40 has a disk-shaped bottom portion 41, a cylindrical portion 42 extending coaxially with the bottom portion 41 from the peripheral edge portion of the bottom portion 41, and a rectangular parallelepiped portion 43 extending from the bottom portion 41 toward the side opposite to the cylindrical portion 42. And include.
The water intake port 15a and the water discharge port 15b are formed in the rectangular parallelepiped portion 43 of the first holder 40. The water intake port 15a penetrates the rectangular parallelepiped portion 43 and the bottom portion 41. The water discharge port 15b penetrates the rectangular parallelepiped portion 43 and the bottom portion 41 (see also FIG. 3 described later).

The second holder 50 has a bottomed tubular shape. The second holder 50 has a shape recessed on the opposite side of the first holder 40. The second holder 50 includes a disk-shaped bottom portion 51 and a cylindrical portion 52 extending coaxially with the bottom portion 51 from the peripheral edge portion of the bottom portion 51 toward the first holder 40. The hydrogen discharge port 15c is formed in the second holder 50.
The hydrogen discharge port 15c is arranged at equal intervals along the circumferential direction of the bottom 51 so as to surround the circular hole 51a penetrating the center of the bottom 51 and the circular hole 51a, and a plurality of arcuate holes penetrating the bottom 51. Includes 51b.

The first holder 40 has a pair of engaging convex portions 44 provided on the outer surface portion of the cylindrical portion 42. The second holder 50 is provided in the cylindrical portion 52 and has a pair of engaging recesses 53 that engage with the corresponding engaging protrusions 44, respectively. The housing 15 is assembled by fitting each of the pair of engaging protrusions 44 into the corresponding engaging recesses 53. Unlike the example of FIG. 2, the first holder 40 may have an engaging concave portion and the second holder 50 may have an engaging convex portion.

The anode 31, the ion exchange membrane 32, the second cathode 34, the first cathode 33 and the elastic member 37 are arranged in this order from the first holder 40 side to the second holder 50 side.
The anode 31 has, for example, a substantially rectangular parallelepiped shape. The anode 31 is, for example, an alloy having a coated surface. The alloy used as the anode may contain tungsten, iron, molybdenum, nickel, titanium, silicon, tantalum, niobium and the like. The anode 31 does not have to be an alloy. The anode 31 may be a noble metal such as lead oxide, tin oxide or platinum, an oxide of the noble metal, carbon, conductive diamond or the like.

The ion exchange membrane 32 is, for example, a circular thin film. The ion exchange membrane 32 may be, for example, either a fluororesin-based or a hydrocarbon resin-based. The ion exchange membrane 32 is preferably a fluororesin-based membrane from the viewpoint of corrosion resistance to ozone and peroxides. Nafion (registered trademark) can be used as the fluororesin. Nafion is a copolymer of a fluororesin based on sulfonated tetrafluoroethylene, and is a polymer having ionic conductivity. In Nafion, anions and electrons do not move, only hydrogen ions, which are cations, move.

The thickness of the ion exchange membrane 32 is, for example, 30 μm or more and 1.5 mm or less. The thickness of the ion exchange membrane 32 is preferably 30 μm or more and 1.0 mm or less. The thickness of the ion exchange membrane 32 is more preferably 30 μm or more and more preferably 200 μm or less. The thickness of the ion exchange membrane 32 is more preferably 50 μm or more and 120 μm or less. The thickness of the ion exchange membrane 32 is particularly preferably 51 μm.

The first cathode 33 has, for example, a disk shape. As the first cathode 33, a substance that is not embrittled by hydrogen is used. Specifically, examples of the substance used as the first cathode 33 include platinum group metals, nickel, stainless steel, titanium, zirconium, gold, silver, carbon, diamond and the like. The first cathode 33 has a plurality of through holes 33a penetrating the first cathode 33.

The second cathode 34 is a laminated body of a plurality of circular sheets having ion exchange performance. The second cathode 34 is arranged between the ion exchange membrane 32 and the first cathode 33. The second cathode 34 includes a carbon cathode 60 made of carbon fibers and a coating member 70 having ion exchange performance and covering the carbon fibers.
The carbon cathode 60 is composed of a circular sheet member 61 made of carbon fibers. In the example of FIG. 2, 11 sheet members 61 are provided, but the number of sheet members 61 is not limited to this. For example, 16 sheet members 61 may be provided.

The elastic member 37 is, for example, an annular disc spring. The elastic member 37 elastically biases the first cathode 33 toward the anode 31 side. As a result, the anode 31, the ion exchange membrane 32, the second cathode 34 and the first cathode 33 can be brought into close contact with each other.
The anode energizing terminal 30, the first cathode energizing terminal 35, and the second cathode energizing terminal 36 are each formed in a spiral shape, for example. The anode energizing terminal 30 is arranged between the anode 31 and the first holder 40 and comes into contact with the anode 31. The first cathode energizing terminal 35 is arranged between the first cathode 33 and the elastic member 37 and comes into contact with the first cathode 33. The second cathode energizing terminal 36 is arranged between the seat members 61 and comes into contact with the seat members 61.

The plurality of wirings 26 include an anode side wiring 80 connected to the anode energizing terminal 30, and a cathode side wiring 81 connected to the first cathode energizing terminal 35 and the second cathode energizing terminal 36.
The first cathode 33 and the second cathode 34 are connected in parallel to the cathode side wiring 81, which is a common wiring, via the first cathode energizing terminal 35 and the second cathode energizing terminal 36, respectively. However, since the second cathode energizing terminal 36 is connected to the tip of the cathode side wiring 81, and the first cathode energizing terminal 35 is connected to the power supply 25 (see also FIG. 4 described later) side of the tip of the cathode side wiring 81. The voltage applied to the second cathode 34 is lower than the voltage applied to the first cathode 33.

FIG. 3 is a vertical sectional view of the electrolytic cell 4.
The housing 15 has an internal space 16 between the first holder 40 and the second holder 50. In the internal space 16 of the housing 15, an anode energizing terminal 30, an anode 31, an ion exchange membrane 32, a first cathode 33, a second cathode 34, a first cathode energizing terminal 35, a second cathode energizing terminal 36, and an elastic member 37 are provided. Be housed.

The internal space 16 is separated into an anode chamber 16A and a cathode chamber 16B by an ion exchange membrane 32. An anode energizing terminal 30 and an anode 31 are arranged in the anode chamber 16A. The cathode chamber 16B houses a first cathode 33, a second cathode 34, a first cathode energizing terminal 35, a second cathode energizing terminal 36, and an elastic member 37.
The anode-side wiring 80 enters the internal space 16 of the housing 15 through, for example, the water intake port 15a provided in the first holder 40. The cathode side wiring 81 enters the internal space 16 of the housing 15 through, for example, the hydrogen discharge port 15c of the second holder 50.

The raw water RW enters the anode chamber 16A from the first water pipe 19 via the water intake port 15a provided in the first holder 40. Ozone is generated by electrolyzing the raw water RW in the anode chamber 16A. The generated ozone is dissolved in the raw material water RW to generate ozone water OW. The ozone water OW generated in the anode chamber 16A is discharged from the anode chamber 16A to the second water pipe 20 via the water discharge port 15b provided in the first holder 40.

The raw water RW enters the cathode chamber 16B from the hydrogen discharge port 15c provided in the second holder 50. The raw material water RW that has entered the cathode chamber 16B from the hydrogen discharge port 15c enters the ion exchange membrane 32 side of the first cathode 33 in the cathode chamber 16B through the through hole 33a of the first cathode 33. Therefore, the cathode chamber 16B is filled with the raw material water RW, and the raw material water RW exists around the second cathode 34.

FIG. 4 is a schematic diagram for explaining the configuration of the second cathode 34.
With reference to FIG. 4, the carbon cathode 60 of the second cathode 34 includes a cathode side portion 62 adjacent to the first cathode 33 and an exchange membrane side portion 63 adjacent to the ion exchange membrane 32. The cathode side portion 62 is composed of a plurality of sheet members 61 on the first cathode 33 side, and the exchange membrane side portion 63 is composed of a plurality of sheet members 61 on the ion exchange membrane 32 side. The second cathode energizing terminal 36 is arranged between the sheet members 61 of the cathode side portion 62. In FIG. 4, for convenience of explanation, the number of sheet members 61 is different from that in FIGS. 2 and 3.

The coating member 70 includes a low-hydrophilic coating member 71 that coats carbon fibers on the cathode side portion 62, and a highly hydrophilic coating member 72 that coats carbon fibers on the exchange film side portion 63. The highly hydrophilic coating member 72 is more hydrophilic than the low hydrophilic coating member 71.
The low hydrophilic coating member 71 contains a semi-hydrophobic ion exchange resin 73. As the semi-hydrophobic ion exchange resin 73, for example, Nafion having a sulfonic acid group 73a is used.

The highly hydrophilic coating member 72 contains a semi-hydrophobic ion exchange resin 74, a hydrophilic ion exchange resin 75, an ion exchange auxiliary agent 76, and a water supply agent 77. As the semi-hydrophobic ion exchange resin 74, for example, Nafion having a sulfonic acid group 74a is used.
The hydrophilic ion exchange resin 75 is a substance having higher hydrophilicity than the semi-hydrophobic ion exchange resins 73 and 74. The hydrophilic ion exchange resin 75 may contain, for example, at least one of an organic conductive polymer such as verazole (registered trademark), a sulfonated polyether sulfone, and modified graphene oxide. As the organic conductive polymer, it is particularly preferable to use a polymer material in which PSD (poly 3,4-ethylene dioxythiophene) is doped with PSS (polystyrene sulfonic acid) and PTS (paratoluene sulfonic acid). The modified graphene oxide may contain a small amount of graphene with either a carboxy group modification or a sulfonic acid group modification.

The ion exchange auxiliary agent 76 is preferably a substance having a higher acid strength than the semi-hydrophobic ion exchange resin 74. The acid strength is the ability as an acid, and the acid strength includes Bronsted acid strength and Lewis acid strength. The ion exchange aid 76 is, for example, a solid acid catalyst. Examples of the solid acid catalyst include zeolite, montmorillonite, 12 tonguest hexaphosphate cesium salt and the like. Since the acid strength of the 12 tonguest hexaphosphate cesium salt is higher than the acid strength of the semi-hydrophobic ion exchange resin 74, it is preferably used as an ion exchange aid 76.

The water supply agent 77 is preferably a substance having high hydrophilicity, a fine particle size, and chemical resistance. Here, chemical resistance means resistance to strong acids and hydrogen. Further, the water supply agent 77 is preferably a solid that is insoluble in water from the viewpoint of preventing diffusion into water. It is preferable that the water supply agent 77 can appropriately retain water, and examples of such a water supply agent 77 include cellulose nanofibers.

The hydrophilicity of the highly hydrophilic coating member 72 becomes higher than that of the low hydrophilic coating member 71 due to the action of the hydrophilic ion exchange resin, the ion exchange auxiliary agent and the water supply agent.
The coating member 70 is formed by an impregnation treatment in which carbon fibers are impregnated with a liquid coating member or a vapor deposition treatment in which a gaseous coating member is vapor-deposited.
According to this embodiment, in the electrolytic cell 4, ozone water OW is generated from the raw material water RW taken into the housing 15 from the water intake port 15a, and the generated ozone water OW is discharged from the water discharge port 15b. To. Since the first cathode 33 is arranged in the housing 15 on the side opposite to the anode 31 with the ion exchange membrane 32 interposed therebetween, the raw material water RW is electrolyzed in the housing 15 and ozone is generated. In the electrolytic cell 4, a second cathode 34 having an ion exchange performance is arranged between the ion exchange membrane 32 and the first cathode 33. Therefore, the mineral component in the raw water RW does not precipitate as a salt between the ion exchange membrane 32 and the first cathode 33, but moves along the surface of the second cathode 34 to the first cathode 33 side in an ionic state. .. Finally, the mineral component precipitate 100 is formed on the surface of the first cathode 33 on the opposite side of the ion exchange membrane 32. Since the mineral component can be suppressed from precipitating between the ion exchange membrane 32 and the first cathode 33, ozone water OW can be efficiently generated.

In particular, even when tap water or the like containing a large amount of mineral components is used as the raw material water RW, ozone water OW can be efficiently generated.
More specifically, the mineral ions are attracted to the semi-hydrophobic ion exchange resin 74 and the hydrophilic ion exchange resin 75 of the highly hydrophilic coating member 72, and are applied to the first cathode 33 having a higher voltage than the carbon cathode 60. Will be carried.

The carbon cathode 60 is not always sufficiently supplied with electric current. Therefore, the mineral components may collect around the semi-hydrophobic ion exchange resin 74 and the hydrophilic ion exchange resin 75, and the ion exchange performance of the second cathode 34 may deteriorate. Even in that case, the ion exchange aid 76 having a higher acid activity than the sulfonic acid group 74a attracts mineral ions. Therefore, the semi-hydrophobic ion exchange resin 74 and the hydrophilic ion exchange resin 75 regain their acid activity. Mineral ions attracted to the ion exchange aid 76 are not deposited around the carbon cathode 60, but are attracted to the first cathode 33 to which a high voltage is applied.

Mineral ions that have reached the first cathode 33 may precipitate between the carbon cathode 60 and the first cathode 33, and the carbon cathode 60 functions as an anode to deprive the mineral salt of electrons. As a result, the mineral salt is ionized again, so that the function of the first cathode 33 as a cathode can be maintained. The reionized mineral component moves to a position where the influence from the carbon cathode 60 is sufficiently reduced, specifically, a position opposite to the carbon cathode 60 with respect to the first cathode 33, and precipitates again.

According to this embodiment, the second cathode 34 includes a carbon cathode 60 and a coating member 70. Since the carbon cathode 60 is made of carbon fiber, its surface area is larger than that of the plate-shaped metal. Since the carbon fiber is coated with the coating member 70 having the ion exchange performance, the ion exchange performance of the second cathode 34 can be improved. Therefore, the movement of the mineral component in the raw water RW to the first cathode 33 side can be promoted. That is, the precipitation of mineral components between the ion exchange membrane 32 and the first cathode 33 can be further suppressed.

According to this embodiment, in the carbon cathode 60, the hydrophilicity of the exchange membrane side portion 63 adjacent to the ion exchange membrane 32 is higher than the hydrophilicity of the cathode side portion 62 adjacent to the first cathode 33. Therefore, the precipitation of mineral components on the ion exchange membrane 32 side can be further suppressed.
The second cathode energizing terminal 36 is arranged between the sheet members 61 of the cathode side portion 62. Therefore, the sheet member 61 of the cathode side portion 62 is pressed against the second cathode energizing terminal 36 by the elastic force of the elastic member 37, so that the carbon fibers may be cut. Further, since the cathode side portion 62 does not come into contact with the ion exchange membrane 32, it does not directly participate in the electrolysis of the raw water RW. Further, the timing at which the ion exchange ability is required of the cathode side portion 62 is later than that of the exchange membrane side portion 63.

Therefore, it is preferable to use the low hydrophilic coating member 71 for the cathode side portion 62, which has a smaller number of substances used for coating than the high hydrophilic coating member 72 and a smaller number of man-hours for manufacturing than the high hydrophilic coating member 72.
However, the coating member 70 needs to be chemically stable even when a large current flows through the carbon cathode 60. Therefore, it is preferable to use Nafion, which has excellent scientific stability, as the low-hydrophilic coating member 71.

According to this embodiment, the carbon cathode 60 is composed of a plurality of sheet members 61. Therefore, the coating member 70 can be changed for each sheet member 61. Thereby, a coating suitable for suppressing the precipitation of mineral components between the ion exchange membrane 32 and the first cathode 33 can be selected for each sheet member 61.
According to this embodiment, the voltage applied to the second cathode 34 is lower than the voltage applied to the first cathode 33. Therefore, the ionic mineral component in the vicinity of the second cathode 34 is likely to be attracted to the first cathode 33 side. Therefore, the movement of the mineral component in the raw water RW to the first cathode 33 side can be promoted. That is, the precipitation of mineral components between the ion exchange membrane 32 and the first cathode 33 can be further suppressed.

According to this embodiment, the raw material water RW stored in the storage unit 3 is sent to the electrolytic cell 4 by the water supply unit 5. The raw material water RW sent to the electrolytic cell 4 is electrolyzed by the electrolytic cell 4 to generate ozone water OW. Then, the ozone water OW generated by the electrolytic cell 4 is sprayed from the spraying unit 6.

<Precipitation amount comparison experiment>
Next, a precipitation amount comparison experiment conducted to demonstrate the salt precipitation suppressing effect of the electrolytic cell 4 will be described.
5A to 5D are images for explaining the result of the precipitation amount comparison experiment.
In the precipitation amount comparison experiment, a first electrolytic cell using a carbon cathode having ion exchange performance as the second cathode and a second electrolytic cell using a carbon cathode having no ion exchange performance as the second cathode were used. In the precipitation amount comparison experiment, the amount of salt adhering to each electrolytic cell was compared after repeated generation of ozone water using tap water as a raw material water using each electrolytic cell.

The number of sheet members of the carbon cathode is different between the first electrolytic cell and the second electrolytic cell. Specifically, the number of carbon cathode sheet members included in the first electrolytic cell is 16, whereas the number of carbon cathode sheet members included in the second electrolytic cell is two.
In the precipitation comparison experiment, ozone water was generated for 2000 cycles using water having a TDS (total dissolved solid matter) of 300 ppm. Water having a TDS of 300 ppm corresponds to tap water. One cycle is to stop the production of ozone for 5 seconds after the generation of ozone is performed for 5 seconds.

After 2000 cycles of ozone water generation, the ion exchange membrane and the second cathode in close contact were taken out from each electrolytic cell, and a still image of the ion exchange membrane was taken. As shown in FIG. 5A, a slight precipitation of salt was observed on the ion exchange membrane taken out from the first electrolytic cell. On the other hand, as shown in FIG. 5B, precipitation of a large amount of salt was observed inside the ion exchange membrane taken out from the second electrolytic cell.

The ion exchange membrane taken out from each electrolytic cell was immersed in 5% hydrochloric acid for 30 minutes for washing, and then a still image of the ion exchange membrane was taken. As shown in FIG. 5C, no significant change was observed in the ion exchange membrane taken out from the first electrolytic cell before and after washing with hydrochloric acid. On the other hand, as shown in FIG. 5D, the ion exchange membrane taken out from the second electrolytic cell had higher transparency than that before washing with hydrochloric acid (see FIG. 5B). That is, it is presumed that mineral salts such as calcium carbonate were removed by washing with hydrochloric acid.
Therefore, when the second cathode uses an electrolytic cell having an ion exchange performance (first electrolytic cell), it is compared with the case where the second cathode uses an electrolytic cell having no ion exchange performance (second electrolytic cell). It was found that the precipitation of mineral salts in the vicinity of the ion exchange membrane can be suppressed.

<Electrolysis experiment>
Next, a first electrolysis experiment for comparing the difference in ozone generation ability depending on the type of coating member and a second electrolysis experiment for comparing the difference in ozone generation ability depending on the presence or absence of the coating member will be described.
In the electrolysis test, five types of electrolysis cells with different coating members were used as samples. The coating members of each sample are as follows.
Sample A: Nafion, Verazole, 12 cesium phosphate hexaphosphate, cellulose nanofiber sample B: Nafion, cellulose nanofiber sample C: Nafion, verazole, cellulose nanofiber sample D: Nafion, 12 tonguest cesium hexaphosphate, cellulose Nanofiber sample E: No ion exchange component

<First electrolysis experiment>
In the first electrolysis experiment, the performances of Sample A to Sample D were compared.
In the first electrolysis experiment, a durability test was conducted under the following conditions. Specifically, from the start of the experiment to 24 hours, a small cycle was repeated in which ozone production was performed for 10 seconds and then ozone production was stopped for 5 seconds. After 24 hours had passed from the start of the experiment, a small cycle was repeated 10 times, and then a large cycle was repeated in which ozone production was stopped for 150 minutes.

In the first electrolysis experiment, water having a TDS of 300 ppm was used from the start to 24 hours. After 24 hours from the start of the experiment, water having a TDS of 450 ppm was used to observe the ozone generation capacity of the electrolytic cell immediately after resting for 150 minutes.
In the first electrolysis experiment, the water temperature was adjusted to 25 ° C or higher and 30 ° C or lower, the water flow rate was adjusted to 1 mL / sec or higher and 1.2 mL / sec or lower, the current was 1.2 A constant current, and the voltage was 18.0 V. It was as follows.

The ozone concentration was measured at each important point and every 24 hours by the ultraviolet absorption method. The voltage value was monitored every second for 24 hours, and the water temperature was measured using a water temperature gauge when measuring the ozone concentration.
Table 1 below is a table showing the results of the first electrolysis experiment. In Table 1, "first time" means the first large cycle, and "at the time of restart" means the second and subsequent large cycles. The “voltage” in Table 1 means the voltage in the electrolytic cell, and the lower the voltage, the smaller the amount of mineral components deposited and the larger the amount of ozone water that can be generated.
The "stabilization time" in Table 1 means the time required for the voltage to stabilize after the start of the large cycle, and the shorter the stabilization time, the more stable the water can be electrolyzed.

When the sample A was used, the time until the voltage became stable was almost 0 seconds at both the first time and the restart, which was very short. As a result, it is inferred that water can be stably electrolyzed immediately after the start of use of the ozone water spray. Further, when the sample A was used, the maximum value of the voltage at the first time was 8.6 V, and the maximum value of the voltage at the time of restart was 9.2 V. From this, it is presumed that the precipitation of mineral components can be sufficiently suppressed by using an electrolytic cell having a second cathode having ion exchange performance.

When the sample B was used, the maximum value of the voltage at the time of restart was 16.5 V, and when the sample C was used, the maximum value of the voltage at the time of restart was 16.2 V. On the other hand, when the sample A was used, the maximum value of the voltage at the time of restart was 8.6 V, and when the sample D was used, the maximum value of the voltage at the time of restart was 11.3 V. That is, the maximum value of the voltage at the time of restart was larger in sample B and sample C than in sample A and sample D.

This result is believed to be related to the fact that Samples B and C do not contain the cesium 12 tonguest 6 phosphate salt as an ion exchange aid.
Specifically, it is presumed that the voltage at the time of restarting increased because the mineral component was deposited at the time of stopping the electrolysis in the sample B and the sample C. In other words, in Sample A and Sample D, it is presumed that the 12 tonguest cesium phosphate 6 phosphate has an effect of suppressing the precipitation of mineral components while electrolysis is stopped.

When sample B was used, the initial stabilization time was 6 minutes and 52 seconds, and when sample D was used, the initial stabilization time was 9 minutes and 50 seconds. On the other hand, in both the case where the sample A was used and the case where the sample C was used, the initial stabilization time was almost 0 seconds. That is, the initial stabilization time was shorter for Sample A and Sample C than for Sample B and Sample D.

This result is considered to be due to the difference in water supply performance between verazole as a hydrophilic ion exchange resin and Nafion as a semi-hydrophobic ion exchange resin. Specifically, because verazole is more hydrophilic than nafion, water is the carbon cathode in sample B and sample D, which are carbon fibers coated with nafion, than in samples A and C, which are carbon fibers coated with verazole. It is difficult to enter the vicinity of. Therefore, it is considered that the stabilization time of Sample A and Sample C is shorter than the stabilization time of Sample B and Sample D.
According to the results of the first electrolysis experiment, it was found that it is preferable to use a coating member containing all of the semi-hydrophobic ion exchange resin, the hydrophilic ion exchange resin, the ion exchange auxiliary agent and the water supply agent as the coating member.

<Second electrolysis experiment>
Next, the second electrolysis experiment will be described. In the second electrolysis experiment, sample A and sample E were compared.
Since sample E has lower mineral resistance than sample A, a large amount of mineral components adhere to the ion exchange membrane and the carbon cathode under the same experimental conditions as in the first electrolysis experiment, making it difficult to measure the voltage. ..
Therefore, for sample A, the results of the first electrolysis experiment were used, and for sample E, the durability test was conducted under different conditions from the first electrolysis experiment.

The conditions for the durability test of sample E are as follows. Specifically, from the start of the experiment to 6 hours, a small cycle was repeated in which ozone production was performed for 10 seconds and then ozone production was stopped for 5 seconds. After 24 hours had passed from the start of the experiment, a small cycle was repeated 10 times, and then a large cycle was repeated in which ozone production was stopped for 30 minutes. In the durability test of sample E, water having a TDS of 300 ppm was used.

In the durability test of sample E, the water temperature was adjusted to 25 ° C. or higher and 30 ° C. or lower, the water flow rate was adjusted to 1 mL / sec or higher and 1.2 mL / sec or lower, the current was 1.2 A constant current, and the voltage was 18. It was set to 0 V or less.
The ozone concentration was measured at each important point and every 6 hours by the ultraviolet absorption method. The voltage value was monitored every second for 24 hours, and the water temperature was measured using a water temperature gauge when measuring the ozone concentration.

Table 2 below is a table showing the results of the second electrolysis experiment. In Table 2, "first time" means the first large cycle, and "at the time of restart" means the second and subsequent large cycles. The “voltage” in Table 2 means the voltage in the electrolytic cell, and the lower the voltage, the smaller the amount of mineral components deposited and the larger the amount of ozone water that can be generated. The “stabilization time” in Table 2 means the time required for the voltage to stabilize after the start of the large cycle, and the shorter the stabilization time, the more stable the water can be electrolyzed.

When the sample E was used, the maximum value of the voltage at the time of resumption was 18.5 V, and the stabilization time at the time of resumption was 60 seconds. On the other hand, when the sample A was used, the maximum value of the voltage at the time of resumption was 8.6 V, and the stabilization time at the time of resumption was almost 0 seconds. Therefore, when the sample E was used, a result was obtained that a large amount of mineral components were precipitated at the time of resumption as compared with the case where the sample A was used.
According to the results of the second electrolysis experiment, it is inferred that an electrolytic cell equipped with a carbon cathode having no ion exchange performance can suppress precipitation of mineral components as compared with an electrolytic cell having a carbon cathode having no ion exchange performance. Will be done.

<Other embodiments>
The present invention is not limited to the embodiments described above, and can be implemented in still other embodiments.
For example, the ozone water spray 1 shown in FIG. 1 has a configuration in which ozone water OW can be sprayed in either a shower-like state or a mist-like state. However, unlike the ozone water spray 1 shown in FIG. 1, an ozone water spray capable of spraying only ozone water OW in either a shower-like state or a mist-like state may be used.
For example, the carbon cathode 60 shown in FIGS. 2 and 3 is composed of a plurality of sheet members 61. However, the carbon cathode 60 does not necessarily have to be composed of the sheet member 61, and may be composed of, for example, a single block of carbon fibers.

For example, as shown in FIG. 4, in the carbon cathode 60, different coating members 70 are applied to the cathode side portion 62 and the exchange membrane side portion 63. However, the highly hydrophilic coating member 72 may be applied to both the cathode side portion 62 and the exchange membrane side portion 63. Alternatively, the low hydrophilic coating member 71 may be applied to both the cathode side portion 62 and the exchange membrane side portion 63.

In this specification, when the numerical range is indicated by using "-" or "-", these include both endpoints and the unit is common, unless otherwise specified.
In addition, various changes can be made within the scope of the claims.

1: Ozone water spray (ozone water sprayer)
3: Storage part 4: Electrolytic cell 5: Water supply part 6: Sprinkling part 15: Housing 15a: Water intake port 15b: Water discharge port 31: Anode 32: Ion exchange membrane 33: First cathode 34: Second cathode 60: Carbon Cathode 61: Sheet member 62: Cathode side part 63: Exchange membrane side part 70: Coating member 71: Low hydrophilic coating member 72: Highly hydrophilic coating member OW: Ozone water RW: Raw material water

Claims (6)

An electrolytic cell that produces ozone water from raw water.
A housing with a water intake that takes in raw water and a water outlet that discharges ozone water.
With the anode arranged in the housing,
An ion exchange membrane placed adjacent to the anode in the housing,
A first cathode arranged in the housing on the opposite side of the anode with the ion exchange membrane interposed therebetween.
An electrolytic cell comprising the ion exchange membrane and a second cathode disposed between the first cathode and having ion exchange performance. The electrolytic cell according to claim 1, wherein the second cathode includes a carbon cathode made of carbon fiber and a coating member having ion exchange performance and coating the carbon fiber. The carbon cathode includes a cathode side portion adjacent to the first cathode and an exchange membrane side portion adjacent to the ion exchange membrane.
The coating member has a low hydrophilic coating member that coats the carbon fiber on the cathode side portion and a high hydrophilic coating member that coats the carbon fiber on the exchange film side portion and has higher hydrophilicity than the low hydrophilic coating member. The electrolytic cell according to claim 2, which includes a sex-coated member. The electrolytic cell according to claim 2 or 3, wherein the carbon cathode is composed of a plurality of sheet members. The electrolytic cell according to any one of claims 1 to 4, wherein the voltage applied to the second cathode is lower than the voltage applied to the first cathode. The electrolytic cell according to any one of claims 1 to 5 and the electrolytic cell.
A storage unit that stores raw water and
A spraying section for spraying ozone water generated by the electrolytic cell,
An ozone water spraying device including a water supply unit that supplies water from the storage unit to the spraying unit via the electrolytic cell.

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