Electrolytic cell and ozone water dispersing device

Abstract

An electrolytic cell and an ozone water dispersing device capable of efficiently generating ozone water. The electrolytic cell (4) generates ozone water (OW) from raw water (RW). The electrolytic cell (4) comprises: an anode (31); an ion exchange membrane (32) arranged adjacent to the anode (31); a first cathode (33) arranged on the opposite side of the anode (31) across the ion exchange membrane (32); a second cathode (34) arranged between the ion exchange membrane (32) and the first cathode (33) and having ion exchange performance; and a housing (15) accommodating the above components. The housing (15) comprises: a water intake (15a) for taking in raw water (RW); and a water discharge port (15b) for discharging ozone water (OW).

Description

Technical Field

[0001] The present invention relates to an electrolytic cell for generating ozone water and an ozone water dispersing device using the electrolytic cell. Background Art

[0002] The electrolytic cell disclosed in the following Patent Document 1 has an anode, a cathode, and an ion exchange membrane. Raw water is passed through the electrolytic cell with a voltage applied between the anode and the cathode, thereby generating ozone water. Specifically, ozone is generated by electrolysis of raw water, and the generated ozone is dissolved in raw water to obtain ozone water.

[0003] When tap water or the like containing more mineral components than deionized water is used as raw water, the mineral components may precipitate as salts between the cathode and the ion exchange membrane in the electrolytic cell of Patent Document 1. This may reduce the efficiency of generating ozone water.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6249200 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The present invention has been accomplished under such background, and an object of the present invention is to provide an electrolytic cell and an ozone water dispersing device capable of efficiently generating ozone water.

[0009] Solutions for solving problems

[0010] The present invention is an electrolytic cell for generating ozone water from raw water, comprising: a shell having a water inlet for taking in raw water and a drain outlet for discharging ozone water; an anode arranged in the shell; an ion exchange membrane arranged in the shell in a manner adjacent to the anode; a first cathode arranged in the shell on the opposite side of the anode across the ion exchange membrane; and a second cathode arranged between the ion exchange membrane and the first cathode and having ion exchange performance.

[0011] The present invention is characterized in that the second cathode includes: a carbon cathode formed of carbon fibers; and a coating member having ion exchange performance and covering the carbon fibers.

[0012] The present invention is characterized in that 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 component includes: a low-hydrophilic coating component, coating the carbon fiber on the cathode side portion; and a high-hydrophilic coating component, coating the carbon fiber on the exchange membrane side portion, and having a higher hydrophilicity than the low-hydrophilic coating component.

[0013] The present invention is characterized in that the carbon cathode is composed of a plurality of sheet members.

[0014] The present invention is characterized in that a voltage applied to the second cathode is lower than a voltage applied to the first cathode.

[0015] The present invention is an ozone water dispersing device, comprising: the electrolytic cell; a storage unit for storing raw water; a dispersing unit for dispersing ozone water generated by the electrolytic cell; and a water supply unit for supplying water from the storage unit to the dispersing unit via the electrolytic cell.

[0016] Effects of the Invention

[0017] According to the present invention, in the electrolytic cell, ozone water is generated from raw water taken into the shell from the water inlet, and the generated ozone water is discharged from the drain port. In the shell, since a first cathode is arranged on the opposite side of the anode across an ion exchange membrane, the raw water is electrolyzed in the shell to generate ozone. In the electrolytic cell, a second cathode with ion exchange performance is arranged between the ion exchange membrane and the first cathode. Therefore, the mineral components in the raw water do not precipitate in the form of salt between the ion exchange membrane and the first cathode, but move in an ionic state along the surface of the second cathode toward the first cathode side. In addition, the mineral components are finally precipitated in the first cathode on the opposite side of the ion exchange membrane. Since the precipitation of mineral components between the ion exchange membrane and the first cathode can be suppressed, ozone water can be efficiently generated.

[0018] In particular, even when tap water or the like containing a larger amount of mineral components than deionized water or the like is used as raw water, ozone water can be efficiently generated.

[0019] According to the present invention, the second cathode includes a carbon cathode and a coating member. The carbon cathode is formed of carbon fibers, so its surface area is larger than that of a plate-like metal. The carbon fibers are coated with a coating member having ion exchange properties, so the ion exchange properties of the second cathode can be improved. Therefore, the mineral components in the raw water can be promoted to move 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.

[0020] According to the present invention, the hydrophilicity of the carbon cathode portion adjacent to the ion exchange membrane is higher than that of the carbon cathode portion adjacent to the first cathode. Therefore, the precipitation of mineral components on the ion exchange membrane side can be further suppressed.

[0021] 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. Thus, a coating member suitable for suppressing the precipitation of mineral components between the ion exchange membrane and the first cathode can be selected for each sheet member.

[0022] According to the present invention, the voltage applied to the second cathode is lower than the voltage applied to the first cathode. Therefore, the mineral components in the ion state near the second cathode are easily attracted to the first cathode side. Therefore, the mineral components in the raw water can be promoted to move to the first cathode side. That is, the precipitation of the mineral components between the ion exchange membrane and the first cathode can be further suppressed.

[0023] According to the present invention, the raw water stored in the storage part is sent to the electrolytic cell by the water supply part. The raw 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 spreading part by the water supply part, and is spread from the spreading part to the outside of the ozone water spreading device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a longitudinal sectional view of an ozone water sprayer equipped with the electrolytic cell of the present invention.

[0025] Figure 2 Exploded view of the electrolytic cell.

[0026] Figure 3 A cross-sectional view of an electrolytic cell.

[0027] Figure 4 It is a schematic diagram for explaining the structure of the second cathode included in the electrolytic cell.

[0028] Figure 5A This is a diagram for explaining the results of a deposition amount comparison experiment when an electrolytic cell having ion exchange performance is used, and is an enlarged view of the surface of the ion exchange membrane before hydrochloric acid cleaning.

[0029] Figure 5B This is a diagram for explaining the results of a deposition amount comparison experiment when an electrolytic cell without ion exchange performance is used, and is an enlarged view of the surface of the ion exchange membrane before hydrochloric acid cleaning.

[0030] Figure 5C This is a diagram for explaining the results of a deposition amount comparison experiment when an electrolytic cell having ion exchange performance is used, and is an enlarged view of the surface of the ion exchange membrane after washing with hydrochloric acid.

[0031] Figure 5D This is a diagram for explaining the results of a deposition amount comparison experiment in the case of using an electrolytic cell without ion exchange performance, and is an enlarged view of the surface of the ion exchange membrane after washing with hydrochloric acid.

[0032] Description of Reference Numerals

[0033] 1: Ozone water sprayer (ozone water dispersing device); 3: Storage unit; 4: Electrolytic cell; 5: Water supply unit; 6: Dispersing unit; 15: Casing; 15a: Water intake port; 15b: Drain port; 31: Anode; 32: Ion exchange membrane; 33: First cathode; 34: Second cathode; 60: Carbon cathode; 61: Sheet member; 62: Cathode side portion; 63: Exchange membrane side portion; 70: Coating member; 71: Low-hydrophilic coating member; 72: High-hydrophilic coating member; OW: Ozone water; RW: Raw water. DETAILED DESCRIPTION

[0034] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0035] <Composition of ozone water sprayer>

[0036] Figure 1 1 is a longitudinal sectional view of an ozone water sprayer 1 as an ozone water dispersing device of the present invention. Figure 1 The ozone water sprayer 1 includes: a housing 2, a storage part 3, an electrolytic cell 4, a water supply part 5, a spreading part 6 and a power supply part 7.

[0037] The housing 2 accommodates a storage unit 3, an electrolytic cell 4, a water supply unit 5, a spreading unit 6, and a power supply unit 7. The storage unit 3 stores raw water RW. The electrolytic cell 4 electrolyzes the raw water RW to generate ozone water. The spreading unit 6 spreads the ozone water OW generated by the electrolytic cell 4 to the outside. The water supply unit 5 supplies water from the storage unit 3 to the spreading unit 6 via the electrolytic cell 4. The power supply unit 7 supplies power to each component of the ozone water sprayer 1.

[0038] The ozone water sprayer 1 generates ozone water OW from raw water RW based on the operation of an operation unit (not shown) such as a switch or a lever by a user, and sprays the generated ozone water OW.

[0039] The housing 2 is composed of a body 10, a neck 11, and a head 12. The body 10 has a tapered shape that becomes thinner as it goes from a flat bottom to an upper side. The neck 11 has a substantially cylindrical shape extending in an upward and downward direction. The head 12 has a substantially square cylindrical shape extending in a manner intersecting the neck 11.

[0040] The storage portion 3 is a container accommodated in the body portion 10 of the casing 2. Examples of the raw water RW stored in the storage portion 3 include pure water and tap water.

[0041] The electrolytic cell 4 is arranged in the storage part 3 near the bottom of the storage part 3. The details will be described later. The electrolytic cell 4 includes a housing 15, and generates ozone water OW by electrolyzing the raw water RW taken into the internal space 16 of the housing 15. The housing 15 has: a water intake port 15a, which takes the raw water RW into the internal space 16; a drain port 15b, which discharges the ozone water OW from the internal space 16; and a hydrogen discharge port 15c, which discharges hydrogen (H2) generated when the ozone water OW is generated.

[0042] The spreading unit 6 includes a rain nozzle 17 for spreading ozone water OW in the form of rain and a mist nozzle 18 for spreading ozone water OW in the form of mist. The rain nozzle 17 is disposed at one end of the head 12 of the housing 2, and the mist nozzle 18 is disposed at the other end of the head 12 of the housing 2.

[0043] The water supply section 5 includes: a first water supply pipe 19, which supplies the raw water RW in the storage section 3 to the water intake 15a of the electrolytic cell 4; a second water supply pipe 20, which supplies the ozone water OW generated by the electrolytic cell 4 from the discharge port 16b of the electrolytic cell 4 to the spreading section 6; and a pump 21, which supplies water from the storage section 3 to the spreading section 6 via the first water supply pipe 19, the electrolytic cell 4 and the second water supply pipe 20.

[0044] The pump 21 is, for example, a diaphragm-driven small pump. The pump 21 is mounted in the first water supply pipe 19. The pump 21 includes: a pump body 22; a water intake port 21a for taking in raw water RW into the pump body 22; and a water discharge port 21b for discharging the raw water RW in the pump body 22. The first water supply pipe 19 includes: a water intake pipe 23, one end of which is connected to the water intake port 21a; and a water discharge pipe 24, one end of which is connected to the water discharge port 21b. The other end of the water intake pipe 23 is located at the bottom side of the water surface WS of the raw water RW in the storage section 3. The other end of the water discharge pipe 24 is connected to the water intake port 15a of the shell 15 of the electrolytic cell 4.

[0045] The pump 21 is switched to a driving state or a stopping state by the user's operation of the operation unit. The spreading mode of the spreading unit 6 is switched to a rain mode for spreading ozone water OW from the rain nozzle 17 or a mist mode for spreading ozone water OW from the mist nozzle 18 by the user's operation of the operation unit.

[0046] The power supply unit 7 includes a power source 25 such as a battery disposed below the storage unit 3 in the body 10 of the housing 2 and a plurality of wires 26 extending from the power source 25 to the electrolytic cell 4. Although not shown, the power supply unit 7 may include wires for supplying power to the pump 21 or the operating unit.

[0047] By driving the pump 21, the raw water RW in the storage unit 3 is supplied to the electrolytic cell 4 via the first water supply pipe 19. The raw water RW is changed into ozone water OW when passing through the electrolytic cell 4. The ozone water OW generated in the electrolytic cell 4 is supplied to the spreading unit 6 via the second water supply pipe 20. Thus, the ozone water OW is discharged from the spreading unit 6. Figure 1 The state where ozone water OW is spread by the rain nozzle 17 is shown.

[0048] Figure 2 It is an exploded view of the electrolytic cell 4. The electrolytic cell 4 is of a separate type and is generally cylindrical in shape.

[0049] Reference Figure 2 The electrolytic cell 4 includes: a housing 15 , an anode power terminal 30 , an anode 31 , an ion exchange membrane 32 , a first cathode 33 , a second cathode 34 , a first cathode power terminal 35 , a second cathode power terminal 36 and an elastic member 37 .

[0050] The housing 15 has a first holder 40 and a second holder 50. The first holder 40 has a bottomed cylindrical shape. The first holder 40 includes a disc-shaped bottom 41, a cylindrical portion 42 extending coaxially with the bottom 41 from the peripheral portion of the bottom 41, and a rectangular parallelepiped portion 43 extending from the bottom 41 to the opposite side of the cylindrical portion 42.

[0051] The water inlet 15a and the drain outlet 15b are formed in the rectangular parallelepiped portion 43 of the first seat body 40. The water inlet 15a penetrates the rectangular parallelepiped portion 43 and the bottom 41. The drain outlet 15b penetrates the rectangular parallelepiped portion 43 and the bottom 41 (also refer to the following description). Figure 3 ).

[0052] The second seat body 50 has a bottomed cylindrical shape. The second seat body 50 has a shape that is recessed toward the opposite side of the first seat body 40. The second seat body 50 includes a disc-shaped bottom 51 and a cylindrical portion 52 that extends from the peripheral portion of the bottom 51 toward the first seat body 40 coaxially with the bottom 51. The hydrogen gas outlet 15c is formed in the second seat body 50.

[0053] The hydrogen outlet 15 c includes a circular hole 51 a penetrating the center of the bottom 51 , and a plurality of arc-shaped holes 51 b arranged at equal intervals along the circumference of the bottom 51 so as to surround the circular hole 51 a and penetrating the bottom 51 .

[0054] The first seat 40 has a pair of engaging protrusions 44 provided on the outer surface of the cylindrical portion 42. The second seat 50 has a pair of engaging recesses 53 provided on the cylindrical portion 52 and respectively engaging with the corresponding engaging protrusions 44. The housing 15 is assembled by inserting the pair of engaging protrusions 44 into the corresponding engaging recesses 53. Figure 2Unlike the example, the first base body 40 has a locking recess and the second base body 50 has a locking protrusion.

[0055] The anode 31 , the ion exchange membrane 32 , the second cathode 34 , the first cathode 33 , and the elastic member 37 are arranged in the above order from the first base 40 side to the second base 50 side.

[0056] The anode 31 has, for example, a substantially rectangular parallelepiped shape. The anode 31 is, for example, an alloy coated on the surface. The alloy used as the anode may contain tungsten, iron, molybdenum, nickel, titanium, silicon, tantalum, niobium, etc. The anode 31 is not necessarily an alloy. The anode 31 may also be a noble metal such as lead oxide, tin oxide, platinum, a noble metal oxide, carbon, conductive diamond, etc.

[0057] The ion exchange membrane 32 is, for example, a circular film. The ion exchange membrane 32 may be, for example, a fluorine resin or a hydrocarbon resin. From the perspective of corrosion resistance to ozone and peroxide, the ion exchange membrane 32 is preferably a fluorine resin. The fluorine resin may be Nafion (registered trademark). Nafion is a fluorine resin copolymer based on sulfonated tetrafluoroethylene and is a polymer with ionic conductivity. In Nafion, anions and electrons do not move, and only hydrogen ions as cations move.

[0058] The thickness of the ion exchange membrane 32 is, for example, 30 μm to 1.5 mm. The thickness of the ion exchange membrane 32 is preferably 30 μm to 1.0 mm. The thickness of the ion exchange membrane 32 is more preferably 30 μm to 200 μm. The thickness of the ion exchange membrane 32 is further preferably 50 μm to 120 μm. The thickness of the ion exchange membrane 32 is particularly preferably 51 μm.

[0059] The first cathode 33 has, for example, a disk shape. As the first cathode 33, a material that is not embrittled by hydrogen is used. Specifically, the material used as the first cathode 33 can include platinum group metals, nickel, stainless steel, titanium, zirconium, gold, silver, carbon, diamond, etc. The first cathode 33 has a plurality of through holes 33a that penetrate the first cathode 33.

[0060] The second cathode 34 is a stack of a plurality of circular sheets having ion exchange performance. The second cathode 34 is disposed between the ion exchange membrane 32 and the first cathode 33. The second cathode 34 includes a carbon cathode 60 formed of carbon fibers and a coating member 70 having ion exchange performance and covering the carbon fibers.

[0061] The carbon cathode 60 is composed of a circular sheet member 61 formed of carbon fibers. Figure 2 In the example of FIG. 1 , 11 sheet members 61 are provided, but the number of sheet members 61 is not limited thereto. For example, 16 sheet members 61 may be provided.

[0062] The elastic member 37 is, for example, an annular disc spring, and the elastic member 37 elastically urges the first cathode 33 toward the anode 31. Thus, the anode 31, the ion exchange membrane 32, the second cathode 34, and the first cathode 33 can be brought into close contact.

[0063] The anode power terminal 30, the first cathode power terminal 35, and the second cathode power terminal 36 are each formed in a spiral shape, for example. The anode power terminal 30 is arranged between the anode 31 and the first seat 40, and is in contact with the anode 31. The first cathode power terminal 35 is arranged between the first cathode 33 and the elastic member 37, and is in contact with the first cathode 33. The second cathode power terminal 36 is arranged between the sheet members 61, and is in contact with the sheet member 61.

[0064] The plurality of wirings 26 include an anode-side wiring 80 connected to the anode power supply terminal 30 , and a cathode-side wiring 81 connected to the first cathode power supply terminal 35 and the second cathode power supply terminal 36 .

[0065] The first cathode 33 and the second cathode 34 are connected in parallel to the cathode side wiring 81 as a common wiring via the first cathode power supply terminal 35 and the second cathode power supply terminal 36, respectively. The second cathode power supply terminal 36 is connected to the top of the cathode side wiring 81, and the first cathode power supply terminal 35 is connected to the power supply 25 closer to the top of the cathode side wiring 81 (also refer to the following). Figure 4 ) side, so the voltage applied to the second cathode 34 is lower than the voltage applied to the first cathode 33.

[0066] Figure 3 It is a longitudinal cross-sectional view of the electrolytic cell 4.

[0067] The housing 15 has an inner space 16 between the first base 40 and the second base 50. The inner space 16 of the housing 15 accommodates the anode power terminal 30, the anode 31, the ion exchange membrane 32, the first cathode 33, the second cathode 34, the first cathode power terminal 35, the second cathode power terminal 36 and the elastic member 37.

[0068] The internal space 16 is partitioned into an anode chamber 16A and a cathode chamber 16B by an ion exchange membrane 32. The anode chamber 16A is provided with an anode power terminal 30 and an anode 31. The cathode chamber 16B accommodates a first cathode 33, a second cathode 34, a first cathode power terminal 35, a second cathode power terminal 36, and an elastic member 37.

[0069] The anode wire 80 enters the internal space 16 of the housing 15 through, for example, the water inlet 15a provided in the first housing 40. The cathode wire 81 enters the internal space 16 of the housing 15 through, for example, the hydrogen outlet 15c of the second housing 50.

[0070] The raw water RW enters the anode chamber 16A from the first water supply pipe 19 via the water inlet 15a provided in the first seat body 40. The raw water RW is electrolyzed in the anode chamber 16A to generate ozone. The generated ozone dissolves in the raw 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 supply pipe 20 via the drain port 15b provided in the first seat body 40.

[0071] The raw water RW enters the cathode chamber 16B from the hydrogen outlet 15c provided in the second seat 50. The raw water RW entering the cathode chamber 16B from the hydrogen outlet 15c enters the cathode chamber 16B via the through hole 33a of the first cathode 33, and enters the cathode chamber 16B closer to the ion exchange membrane 32 than the first cathode 33. Therefore, the cathode chamber 16B is filled with the raw water RW, and the raw water RW exists around the second cathode 34.

[0072] Figure 4 It is a schematic diagram for explaining the structure of the second cathode 34 .

[0073] Reference Figure 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 power terminal 36 is disposed between the sheet members 61 of the cathode side portion 62. Figure 4 For the sake of convenience, the number of sheet members 61 and Figure 2 and Figure 3 different.

[0074] The coating member 70 includes a low-hydrophilic coating member 71 covering carbon fibers at the cathode side portion 62 and a high-hydrophilic coating member 72 covering carbon fibers at the exchange membrane side portion 63. The high-hydrophilic coating member 72 has higher hydrophilicity than the low-hydrophilic coating member 71.

[0075] The low-hydrophilic coating member 71 includes a semi-hydrophobic ion exchange resin 73. As the semi-hydrophobic ion exchange resin 73, for example, Nafion having a sulfonic acid group 73a can be used.

[0076] The highly hydrophilic coating member 72 includes a semi-hydrophobic ion exchange resin 74, a hydrophilic ion exchange resin 75, an ion exchange aid 76, and a water supply agent 77. For the semi-hydrophobic ion exchange resin 74, for example, Nafion having a sulfonic acid group 74a can be used.

[0077] The hydrophilic ion exchange resin 75 is a substance having a higher hydrophilicity than the semi-hydrophobic ion exchange resins 73 and 74. The hydrophilic ion exchange resin 75 may include, for example, at least one of an organic conductive polymer such as Verazole (registered trademark), sulfonated polyethersulfone, and modified graphene oxide. As the organic conductive polymer, it is particularly preferred to use a polymer material in which PEDOT (poly 3,4-ethylenedioxythiophene) is doped with PSS (polystyrene sulfonic acid) and PTS (toluene sulfonic acid). The modified graphene oxide may include at least one of carbonyl-modified or sulfonic acid-modified graphene.

[0078] The ion exchange aid 76 is preferably a substance with a higher acid strength than the semi-hydrophobic ion exchange resin 74. Acid strength refers to the ability to act as an acid, and acid strength includes Bronsted acid strength and Lewis acid strength. The ion exchange aid 76 is, for example, a solid acid catalyst. Examples of solid acid catalysts include zeolite, montmorillonite, cesium dodecatungsten hexaphosphate, and the like. Since the acid strength of cesium dodecatungsten hexaphosphate is higher than that of the semi-hydrophobic ion exchange resin 74, it is preferably used as the ion exchange aid 76.

[0079] The water supply agent 77 is preferably a substance with high hydrophilicity, small particle size, and chemical resistance. Among them, chemical resistance refers to resistance to strong acid and hydrogen. In addition, from the perspective of preventing diffusion into water, the water supply agent 77 is preferably a solid that is insoluble in water. The water supply agent 77 is preferably able to appropriately retain water, and as such a water supply agent 77, for example, cellulose nanofibers can be cited.

[0080] Due to the effects of the hydrophilic ion exchange resin, the ion exchange aid, and the water supply agent, the hydrophilicity of the highly hydrophilic coating member 72 becomes higher than the hydrophilicity of the low hydrophilic coating member 71 .

[0081] The coating member 70 is formed by an impregnation process in which a liquid coating member is impregnated into the carbon fibers or an evaporation coating process in which a gaseous coating member is evaporatively coated.

[0082] According to the present embodiment, in the electrolytic cell 4, ozone water OW is generated from raw water RW taken into the housing 15 from the water inlet 15a, and the generated ozone water OW is discharged from the drain port 15b. The first cathode 33 is arranged on the opposite side of the anode 31 in the housing 15 via the ion exchange membrane 32, so that the raw water RW is electrolyzed in the housing 15 to generate ozone. In the electrolytic cell 4, a second cathode 34 having ion exchange performance is arranged between the ion exchange membrane 32 and the first cathode 33. Therefore, the mineral components in the raw water RW do not precipitate in the form of salt between the ion exchange membrane 32 and the first cathode 33, but move to the first cathode 33 side along the surface of the second cathode 34 in an ion state. In addition, the precipitate 100 of the mineral components is finally formed on the surface of the first cathode 33 on the opposite side of the ion exchange membrane 32. Since the precipitation of the mineral components between the ion exchange membrane 32 and the first cathode 33 can be suppressed, the ozone water OW can be efficiently generated.

[0083] In particular, even when tap water or the like containing a large amount of mineral components is used as the raw water RW, ozone water OW can be efficiently generated.

[0084] More specifically, the mineral ions are adsorbed by the semi-hydrophobic ion exchange resin 74 and the hydrophilic ion exchange resin 75 of the highly hydrophilic coating member 72 , and transported to the first cathode 33 to which a higher voltage than that of the carbon cathode 60 is applied.

[0085] The carbon cathode 60 is not always fully supplied with current. Therefore, there is a risk that mineral components gather around the semi-hydrophobic ion exchange resin 74 and the hydrophilic ion exchange resin 75, resulting in a decrease in the ion exchange performance of the second cathode 34. Even in this case, the ion exchange aid 76 having an acid activity higher than that of the sulfonic acid group 74a will adsorb mineral ions. Therefore, the semi-hydrophobic ion exchange resin 74 and the hydrophilic ion exchange resin 75 will restore their acid activity. The mineral ions adsorbed on the ion exchange aid 76 are not precipitated around the carbon cathode 60 but are attracted to the first cathode 33 to which a high voltage is applied.

[0086] The mineral ions reaching the first cathode 33 may be precipitated between the carbon cathode 60 and the first cathode 33, but the carbon cathode 60 functions as an anode and takes electrons from the mineral salt. 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 re-ionized mineral components move to a position where the influence from the carbon cathode 60 is sufficiently reduced, specifically, to a position on the opposite side of the carbon cathode 60 relative to the first cathode 33 and precipitate again.

[0087] According to the present embodiment, the second cathode 34 includes a carbon cathode 60 and a coating member 70. The carbon cathode 60 is formed of carbon fibers, so its surface area is larger than that of a plate-like metal. The carbon fibers are coated with the coating member 70 having ion exchange performance, so the ion exchange performance of the second cathode 34 can be improved. Therefore, the mineral components in the raw water RW can be promoted to move to the first cathode 33 side. That is, the precipitation of the mineral components between the ion exchange membrane 32 and the first cathode 33 can be further suppressed.

[0088] According to the present embodiment, the hydrophilicity of the membrane side portion 63 adjacent to the ion exchange membrane 32 in the carbon cathode 60 is higher than that 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.

[0089] The second cathode power 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 toward the second cathode power terminal 36 due to the elastic force of the elastic member 37, so there is a risk of cutting the carbon fiber. In addition, since the cathode side portion 62 does not contact the ion exchange membrane 32, it does not directly participate in the electrolysis of the raw water RW. Moreover, the cathode side portion 62 requires ion exchange capacity later than the exchange membrane side portion 63.

[0090] Therefore, the cathode side portion 62 preferably uses the low-hydrophilic coating member 71 which uses a smaller amount of coating material and requires less manufacturing man-hours than the highly hydrophilic coating member 72 .

[0091] However, the coating member 70 needs to be chemically stable even when a large current flows through the carbon cathode 60. Therefore, as the low-hydrophilic coating member 71, Nafion, which is excellent in chemical stability, is preferably used.

[0092] According to the present 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. Thus, a coating member 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.

[0093] According to the present embodiment, the voltage applied to the second cathode 34 is lower than the voltage applied to the first cathode 33. Therefore, the mineral components in the ion state near the second cathode 34 are easily attracted to the first cathode 33 side. Therefore, the mineral components in the raw water RW can be promoted to move to the first cathode 33 side. That is, the precipitation of the mineral components between the ion exchange membrane 32 and the first cathode 33 can be further suppressed.

[0094] According to the present embodiment, the raw water RW stored in the storage unit 3 is sent to the electrolytic cell 4 by the water sending unit 5. The raw 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 dispersed from the dispersion unit 6.

[0095] <Precipitation amount comparison experiment>

[0096] Next, a precipitation amount comparison experiment conducted to verify the salt precipitation suppressing effect of the electrolytic cell 4 will be described.

[0097] Figure 5A to Figure 5D These are images for explaining the results of the precipitation amount comparison experiment.

[0098] In the precipitation amount comparison experiment, a first electrolytic cell using a carbon cathode with ion exchange performance as the second cathode and a second electrolytic cell using a carbon cathode without ion exchange performance as the second cathode were used. In the precipitation amount comparison experiment, ozone water was repeatedly generated using tap water as raw water in each electrolytic cell, and the amount of salt attached to each electrolytic cell was compared.

[0099] The first electrolytic cell and the second electrolytic cell have different numbers of carbon cathode sheet members. Specifically, the first electrolytic cell has 16 carbon cathode sheet members, while the second electrolytic cell has 2 carbon cathode sheet members.

[0100] In the precipitation amount comparison experiment, water with a TDS (total dissolved solids) of 300 ppm was used to generate ozone water for 2000 cycles. Water with a TDS of 300 ppm is equivalent to tap water. One cycle is to generate ozone for 5 seconds and then stop generating ozone for 5 seconds.

[0101] After 2000 cycles of ozone water generation, the ion exchange membrane and the second cathode in close contact were removed from each electrolytic cell, and a still image of the ion exchange membrane was taken. Figure 5A As shown in FIG. 1 , trace amounts of salt precipitation were observed on the ion exchange membrane taken out from the first electrolytic cell. Figure 5B As shown, a large amount of salt precipitation was observed inside the ion exchange membrane taken out from the second electrolytic cell.

[0102] The ion exchange membranes taken out from each electrolytic cell were immersed in 5% hydrochloric acid for 30 minutes for cleaning, and then a still image of the ion exchange membranes was taken. Figure 5C As shown in FIG. 1 , no significant changes were observed in the ion exchange membrane taken out from the first electrolytic cell before and after the hydrochloric acid cleaning. Figure 5D As shown, the ion exchange membrane taken out from the second electrolytic cell and the ion exchange membrane before washing with hydrochloric acid (refer to Figure 5B) compared to the ion exchange membrane. That is, it can be inferred that mineral salts such as calcium carbonate are removed by washing with hydrochloric acid.

[0103] This shows that when using an electrolytic cell whose second cathode has ion exchange performance (first electrolytic cell), the precipitation of mineral salts near the ion exchange membrane can be suppressed compared with the case of using an electrolytic cell whose second cathode does not have ion exchange performance (second electrolytic cell).

[0104] <Electrolysis experiment>

[0105] Next, a first electrolysis experiment for comparing differences in ozone generation capabilities depending on the type of coating member and a second electrolysis experiment for comparing differences in ozone generation capabilities depending on the presence or absence of the coating member will be described.

[0106] In the electrolysis test, five types of electrolytic cells with different coating members were used as samples. The coating members of each sample were as follows.

[0107] Sample A: Nafion, Verazole, cesium dodecatungstate hexaphosphate, cellulose nanofibers

[0108] Sample B: Nafion, cellulose nanofibers

[0109] Sample C: Nafion, Verazole, cellulose nanofibers

[0110] Sample D: Nafion, cesium dodecatungstate hexaphosphate, cellulose nanofibers

[0111] Sample E: No ion exchange component

[0112] <First electrolysis experiment>

[0113] In the first electrolysis experiment, the performances of samples A to D were compared.

[0114] In the first electrolysis experiment, a durability test was conducted under the following conditions. Specifically, during the 24-hour period from the start of the experiment, a small cycle was repeated in which ozone generation was stopped for 5 seconds after 10 seconds of ozone generation. After 24 hours from the start of the experiment, a large cycle was repeated in which ozone generation was stopped for 150 minutes after 10 small cycles.

[0115] In the first electrolysis experiment, water with a TDS of 300 ppm was used for 24 hours from the start. After 24 hours from the start of the experiment, water with a TDS of 450 ppm was used to observe the ozone generation capacity of the electrolytic cell just after being stopped for 150 minutes.

[0116] In the first electrolysis experiment, the water temperature was adjusted to 25° C. to 30° C., the water flow rate was adjusted to 1 mL / s to 1.2 mL / s, the current was set to a constant current of 1.2 A, and the voltage was set to 18.0 V or less.

[0117] The ozone concentration was measured every 24 hours at each major location using the ultraviolet absorption method. The voltage value was monitored every second for 24 hours, and the water temperature was measured using a water thermometer during the ozone concentration measurement.

[0118] 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 "restart" means the large cycle after the second time. "Voltage" in Table 1 means the voltage in the electrolytic cell. The lower the voltage, the less the precipitation of mineral components, and the more ozone water can be generated.

[0119] The "stabilization time" in Table 1 indicates the time required for the voltage to stabilize after the start of the large cycle. The shorter the stabilization time, the more stably water can be electrolyzed.

[0120] Table 1

[0121]

[0122] When using sample A, the time until the voltage stabilizes is about 0 seconds, which is very short, both for the first time and when restarting. Therefore, it is inferred that water can be stably electrolyzed immediately after the ozone water sprayer is used. In addition, when using sample A, the maximum value of the voltage is 8.6V for the first time, and the maximum value of the voltage when restarting is 9.2V. Therefore, it is inferred that the precipitation of mineral components can be fully suppressed by using an electrolytic cell having a second cathode with ion exchange performance.

[0123] When sample B was used, the maximum value of the voltage at the restart was 16.5 V, and when sample C was used, the maximum value of the voltage at the restart was 16.2 V. On the other hand, when sample A was used, the maximum value of the voltage at the restart was 8.6 V, and when sample D was used, the maximum value of the voltage at the restart was 11.3 V. That is, samples B and C had a larger maximum value of the voltage at the restart than samples A and D.

[0124] This result is considered to be related to the fact that Sample B and Sample C contain cesium dodecatungstate hexaphosphate as an ion exchange aid.

[0125] Specifically, it is presumed that mineral components were precipitated in Samples B and C when electrolysis was stopped, so the voltage at the restart became higher. In other words, it is presumed that in Samples A and D, cesium dodecatungsten hexaphosphate has the effect of suppressing the precipitation of mineral components during electrolysis stop.

[0126] When using sample B, the first stabilization time was 6 minutes and 52 seconds, and when using sample D, the first stabilization time was 9 minutes and 50 seconds. On the other hand, the first stabilization time was about 0 seconds regardless of whether using sample A or using sample C. That is, regarding the first stabilization time, samples A and sample C were shorter than samples B and sample D.

[0127] This result is considered to be caused by the difference in water supply performance between Verazole, a hydrophilic ion exchange resin, and Nafion, a semi-hydrophobic ion exchange resin. Specifically, since Verazole is more hydrophilic than Nafion, it is more difficult for water to enter the vicinity of the carbon cathode in samples B and D in which Nafion is coated on the carbon fiber than in samples A and C in which Verazole is coated on the carbon fiber. Therefore, it is considered that the stabilization time of samples A and C is shorter than that of samples B and D.

[0128] From the results of the first electrolysis experiment, it is found that it is preferable to use a coating member containing all of a semi-hydrophobic ion exchange resin, a hydrophilic ion exchange resin, an ion exchange aid, and a water supply agent as the coating member.

[0129] <Second electrolysis experiment>

[0130] Next, the second electrolysis experiment is described. In the second electrolysis experiment, sample A and sample E are compared.

[0131] Sample E has lower mineral resistance than Sample A. Therefore, under the same experimental conditions as those in the first electrolysis experiment, a large amount of mineral components adhered to the ion exchange membrane and the carbon cathode, making it difficult to measure the voltage.

[0132] Therefore, the results of the first electrolysis test were used for sample A, and a durability test was performed on sample E under conditions different from those in the first electrolysis test.

[0133] The conditions of the durability test of sample E are as follows. Specifically, during a period of 6 hours from the start of the test, a small cycle in which ozone generation was stopped for 5 seconds after 10 seconds of ozone generation was repeated as one cycle. After 24 hours from the start of the test, a large cycle in which ozone generation was stopped for 30 minutes after 10 small cycles was repeated as one cycle. In the durability test of sample E, water with a TDS of 300 ppm was used.

[0134] In the endurance test of sample E, the water temperature was adjusted to 25° C. to 30° C., the water flow rate was adjusted to 1 mL / s to 1.2 mL / s, the current was set to a constant current of 1.2 A, and the voltage was set to 18.0 V or less.

[0135] The ozone concentration was measured every 6 hours at each major location using the ultraviolet absorption method. The voltage value was monitored every second for 24 hours, and the water temperature was measured using a water thermometer during the ozone concentration measurement.

[0136] 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 "starting again" means the large cycle after the second time. The "voltage" in Table 2 means the voltage in the electrolytic cell. The lower the voltage, the less the precipitation of mineral components, and the more ozone water can be generated. The "stabilization time" in Table 2 means the time required for the voltage to stabilize after the large cycle starts. The shorter the stabilization time, the more stable the water can be electrolyzed.

[0137] Table 2

[0138]

[0139] When using sample E, the maximum value of the voltage at the restart was 18.5 V, and the stabilization time at the restart was 60 seconds. On the other hand, when using sample A, the maximum value of the voltage at the restart was 8.6 V, and the stabilization time at the restart was about 0 seconds. Thus, the following structure was obtained: when using sample E, more mineral components were precipitated at the restart than when using sample A.

[0140] Based on the results of the second electrolysis experiment, it is estimated that the electrolytic cell including the carbon cathode having ion exchange performance can suppress the precipitation of mineral components compared with the electrolytic cell including the carbon cathode not having ion exchange performance.

[0141] <Other embodiments>

[0142] The present invention is not limited to the above-described embodiments, but can be implemented in other forms.

[0143] For example, Figure 1 The ozone water sprayer 1 shown is a structure capable of dispersing ozone water OW in either the form of rain or mist. Figure 1 The ozone water sprayer 1 shown is different from the ozone water sprayer 1 and is an ozone water sprayer that can only spray the ozone water OW in one of the states of rain and mist.

[0144] For example, Figure 2 and Figure 3 The carbon cathode 60 shown is composed of a plurality of sheet members 61. However, the carbon cathode 60 is not necessarily composed of the sheet members 61, and may be composed of, for example, a single carbon fiber block.

[0145] For example, Figure 4As shown, the cathode side portion 62 and the exchange membrane side portion 63 of the carbon cathode 60 are coated with different coating members 70. However, it is also possible that the highly hydrophilic coating member 72 is coated on both the cathode side portion 62 and the exchange membrane side portion 63. Alternatively, it is also possible that the low hydrophilic coating member 71 is coated on both the cathode side portion 62 and the exchange membrane side portion 63.

[0146] In the present specification, when “~” or “-” is used to express a numerical range, unless otherwise specified, these two symbols include both end points and the units are the same.

[0147] In addition, various changes can be made within the scope of the claims.

Claims

1. An electrolytic cell for generating ozone water from raw water, characterized in that: include: The housing has a water inlet for taking in raw water and a drain outlet for discharging ozone water; an anode, disposed in the housing; an ion exchange membrane disposed within the housing adjacent to the anode; a first cathode disposed in the housing on the opposite side of the anode via the ion exchange membrane; as well as a second cathode, disposed between the ion exchange membrane and the first cathode, and having ion exchange performance; The precipitate is formed on the surface of the first cathode opposite to the ion exchange membrane; The second cathode includes: a carbon cathode formed of carbon fibers; and a coating member having ion exchange properties and covering the carbon fibers; 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 includes: a low-hydrophilic coating member covering the carbon fiber on the cathode side; and a high-hydrophilic coating member covering the carbon fiber on the exchange membrane side and having higher hydrophilicity than the low-hydrophilic coating member.

2. The electrolytic cell according to claim 1, characterized in that The carbon cathode is composed of a plurality of sheet members.

3. The electrolytic cell according to any one of claims 1 to 2, characterized in that A voltage applied to the second cathode is lower than a voltage applied to the first cathode.

4. An ozone water dispersing device, characterized in that: include: The electrolytic cell according to any one of claims 1 to 3; The storage part stores the raw water; A spreading unit, which spreads the ozone water generated by the electrolytic cell; as well as The water supply unit supplies water from the storage unit to the spreading unit via the electrolytic cell.

Images