JP4637885B2 - Ozone water generator - Google Patents

Description

  The present invention relates to an ozone water generator that generates ozone water by electrolysis of water.

In recent years, ozone water has been widely used for applications such as sterilization of foods and deodorization of malodorous gases, and many examples of knowledge have begun to be published in the fields of medical care and nursing care. Also in the semiconductor manufacturing area, the feature of ozone oxidation with respect to the ultrafine structure is recognized, and the use of ozone water is essential.
As such a method for producing ozone water, the anode electrode is pressed against one surface of the cation exchange membrane, and the raw material water is brought into direct contact with the electrolytic surface of the catalyst electrode formed by pressing the cathode electrode against the other surface. The thing using the direct electrolysis method which produces | generates ozone water by electrolysis of is known (for example, refer patent document 1).
JP-A-8-134678

By the way, in order to increase the efficiency of ozone water generation using electrolysis, various improved technologies have been studied as an anode electrode based on an ozone water generation catalyst such as lead dioxide, platinum, and diamond. In addition to the selection of the catalyst electrode used for the cathode electrode, improvement of its electrical characteristics is also regarded as important.
The present invention has been made in view of the above circumstances, and an object thereof is to provide an ozone water generation apparatus that can increase the electrical conductivity on the cathode electrode side and further increase the ozone water generation efficiency at a low voltage. Yes.

In order to solve the above-mentioned problem, the invention of claim 1 is, for example, as shown in FIG. 1, wherein the anode electrode 22 is pressed against one surface of the cation exchange membrane 21 and the cathode electrode 23 is pressed against the other surface. In the ozone water generating apparatus 100 that generates the ozone water by applying a direct current voltage between the anode electrode and the cathode electrode and bringing the raw material water into contact with the anode electrode,
Using a material having an ozone generation catalyst function for the anode electrode,
The cathode electrode includes a first cathode electrode portion 231 made of a material having the ozone generation catalyst function, and a second cathode electrode portion 232 made of at least one metal of silver, copper, gold or aluminum, The first cathode electrode part is disposed on the cation exchange membrane side ,
The mass or surface area of the second cathode electrode part is equal to or greater than the mass or surface area of the first cathode electrode part .

The invention of claim 2 is the ozone water generator according to claim 1,
The material having an ozone generation catalytic function is platinum, gold, or a coating metal thereof.

The invention of claim 4 is the ozone water generator according to claim 1 or 2 ,
The silver, copper, gold or aluminum used for the second cathode electrode part is silver, copper, gold or aluminum having a silver chloride layer.

  According to the present invention, deterioration of the cation exchange membrane can be prevented, and ozone water having a low voltage and a high concentration can be generated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view schematically showing an outline of the ozone water generator 100.
The ozone water generating device 100 is configured by arranging a catalyst electrode 2 in a container 1 into which raw water (for example, tap water or purified water) flows, and an anode is formed by applying a DC voltage to the catalyst electrode 2. This device generates ozone water by generating ozone bubbles on the side and dissolving the ozone bubbles in water.
The container 1 has a rectangular parallelepiped shape that is long in the vertical direction and closed at both upper and lower ends, and has inflow paths 11 a and 11 b for flowing raw material water into the container 1 on the lower surface. In addition, outflow paths 12a and 12b are provided for flowing out the ozone water on the anode side and the cathode water on the cathode side generated in the container 1.
The inflow channels 11a and 11b are connected to, for example, a small pump with a constant discharge pressure connected to a tank in which raw material water is stored, or a water tap. The outflow path 12a is connected to a tank for storing ozone water generated in the container 1, a nozzle for ejecting ozone water, and the like, and the outflow path 12b is connected to a tank for storing cathode water and a drain line. . Further, an insertion hole 13 into which an upper end portion of a cation exchange membrane 21 described later is inserted is formed on the inner wall surface of the container 1 between the two inflow passages 11a and 11b, and between the two outflow passages 12a and 12b. An insertion hole 14 into which the lower end of the cation exchange membrane 21 is inserted is also formed on the inner wall surface of the container 1.
In the container 1, raw material water flows from the inflow channels 11a and 11b, and water flows from the inflow channels 11a and 11b to the outflow channels 12a and 12b.

The catalyst electrode 2 is arranged at a substantially central portion in the container 1, and has a cation exchange membrane 21, an anode electrode 22 pressed against one of both surfaces of the cation exchange membrane 21, and a pressure contact with the other surface. The cathode electrode 23 is provided. The cation exchange membrane 21 has an upper end portion fitted into the insertion hole 13 and a lower end portion fitted into the insertion hole 14 to be fixed. Further, a concave portion is formed on the inner wall surface of the container 1 facing the anode electrode 22 side, and a holding plate 15 for holding the anode electrode 22 is attached in the concave portion, so that the anode electrode 22 is attached to the holding plate 15. Is retained. Similarly, a concave portion is formed on the inner wall surface of the container 1 facing the cathode electrode 23 side, and a holding plate 16 for holding the cathode electrode 23 is attached in the concave portion, and the cathode electrode 23 is attached to the holding plate 16. Is retained. Thus, by arranging the cation exchange membrane 21, the anode electrode 22, and the cathode electrode 23 in the container 1, the anode side and the cathode side are separated by the cation exchange membrane 21, and the outer periphery of the cation exchange membrane 21. Can be fixed to the container 1 and is sealed so that raw water, ozone water, cathode water and the like do not leak outside. Further, the anode plate 22 and the cathode electrode 23 are appropriately pressed against the cation exchange membrane 21 side by the holding plates 15 and 16. And the raw material water which flowed in from the inflow paths 11a and 11b contacts the anode electrode 22 and the cathode electrode 23 continuously, respectively.
An output terminal 24 of a power supply device (not shown) is electrically connected between the anode electrode 22 and the cathode electrode 23 so that a DC voltage is applied. That is, the anode electrode 22 and the cathode electrode 23 are connected to the power supply device via the conductive wires to the electrodes 22 and 23. The applied DC voltage is preferably 6 to 15 volts, for example.

  As the cation exchange membrane 21, a conventionally known one can be used, and a fluorine-based cation exchange membrane having strong durability against the generated ozone can be used. For example, a thickness of 100 to 300 μm is preferable.

  The anode electrode 22 is not closely attached so as to completely cover the cation exchange membrane 21, and has a large number of through holes, and the cation exchange membrane 21 has a contact portion and a non-contact portion. It is piled up. That is, it is preferable that the anode electrode 22 has a grating shape or a punching metal shape. FIG. 1 shows a case where the anode electrode 22 has a grating shape. Specifically, the grating shape is a lattice shape in which wires are welded, and the punching metal shape is a porous plate shape in which a large number of through holes are formed in a metal plate.

  As the anode electrode 22, a material having an ozone generation catalyst function is used. Specific examples include β-lead dioxide, platinum, platinum group (palladium, rhodium, ruthenium), gold, carbon (graphite), diamond and the like. Among these noble metals, platinum, gold is preferable in terms of stability. Alternatively, it is preferable to use a coating metal thereof, and in particular, when a metal obtained by coating platinum on titanium is used, the product cost can be reduced. The covering process can be performed by, for example, plating or heat deposition.

  By using the grating-like anode electrode 22 in this way, the intersection part of the members constituting the anode electrode 22 protrudes sharply and protrudes to the outer surface to generate a vortex in contact with the water flow, and the fine bubbles of ozone generated at the anode electrode 22 Can be dissolved to accelerate dissolution.

The cathode electrode 23 includes a first cathode electrode portion 231 made of a material having an ozone generation catalyst function and a second cathode electrode portion 232 made of at least one metal of silver, copper, gold, or aluminum. Yes. As the first cathode electrode portion 231 made of a material having an ozone generation catalyst function, the same noble metal as the above-described anode electrode 22 can be used, and platinum, gold, or a coating metal thereof is used in terms of stability. It is preferable to use a metal in which titanium is coated with platinum, and the product cost can be reduced. The first cathode electrode portion 231 is disposed so as to contact the cation exchange membrane 21, and the second cathode electrode portion 232 is disposed on the surface of the first cathode electrode portion 231 opposite to the cation exchange membrane 21. They are placed one on top of the other.
Here, the mass or surface area of silver, copper, gold or aluminum used for the second cathode electrode part 232 is equal to the mass or surface area of the material having an ozone generation catalytic function used for the first cathode electrode part 231. Or larger than that is preferable. Specifically, when 1 g of platinum in the first cathode electrode part 231 is 1 g, it is preferable to increase silver, copper, gold or aluminum in the second cathode electrode part 232 to 1 g or more. The mass or surface area of silver, gold or aluminum used for the second cathode electrode part 232 is equal to or larger than the mass or surface area of the material having an ozone generation catalyst function used for the first cathode electrode part 231. In this case, silver, copper, gold or aluminum is a metal having a very good electric conductivity, and it is easy to ensure a good electric conductivity of the cathode electrode 23. As a result, hydrogen ions from the anode electrode 22 to the cathode electrode 23 are obtained. This is to make it easier to move.
Furthermore, it is preferable that silver, copper, gold, or aluminum used for the second cathode electrode 232 is silver, copper, gold, or aluminum having a silver chloride layer. Having a silver chloride layer includes, for example, silver, copper, gold, or aluminum having a silver chloride coating on the surface. Silver chloride is also used as a reference electrode for ozone measurement, has high ion mobility necessary for ozone generation, maintains a stable cathode potential, and can stably generate ozone at the anode electrode 22. As described above, when silver, copper, gold, or aluminum used for the second cathode electrode portion 232 is silver, copper, gold, or aluminum having a silver chloride layer, ions move from the anode electrode 22 to the cathode electrode 23. Thus, even if purified water having low electrical conductivity is used as raw material water, a sufficient electrolysis current flows, ozone is generated, and ozone water can be generated.
Further, the first and second cathode electrode portions 231 and 232 are preferably formed in a grating shape similarly to the anode electrode 22. In particular, the first and second cathode electrode portions 231 and 232 are more prominent than the anode electrode 22. It is preferable that it is formed so that the roughness of is rough.
The cation exchange membrane 21, the anode electrode 22, and the cathode electrode 23 are formed in a flat plate shape, and are held in pressure contact with the holding plates 15 and 16 in the container 1 to form the catalyst electrode 2.

Next, a method for generating ozone water using the ozone water generating apparatus 100 having the above-described configuration will be described.
Raw material water is caused to flow into the container 1 from the inflow channels 11a and 11b, and the raw material water is continuously brought into contact with the surface of the anode electrode 22. At the same time, a predetermined voltage is applied between the anode electrode 22 and the cathode electrode 23 by driving the power supply device. By this energization, the raw water is electrolyzed, and hydrogen in the raw water passes through the cation exchange membrane 21 from the anode electrode 22 side and accelerates and moves to the cathode electrode 23 side. As a result, ozone bubbles are generated on the anode electrode 22 side, and hydrogen bubbles are generated on the cathode electrode 23 side.

Here, on the anode electrode 22 side, the direction of the flow of raw material water is complicated due to slight unevenness of the anode electrode 22 and becomes a vortex. Therefore, on the anode electrode 22 side, the generated ozone bubbles are quickly taken into water and dissolved to generate ozone water, and between the anode electrode 22 and the cation exchange membrane 21 (more precisely, the anode electrode 22 and the cathode electrode). 23), a state where a large amount of current flows is ensured.
When ozone water is generated in this way, the ozone water flows out into the outflow path 12a and is stored in an ozone water storage tank or the like.
On the other hand, on the cathode electrode 23 side, hydrogen bubbles are generated and discharged together with the cathode water from the outflow path 12b.

As described above, according to the embodiment of the present invention, the anode electrode 22 is made of a material having an ozone generation catalyst function, and the cathode electrode 23 is made of a material having an ozone generation catalyst function. Since the first cathode electrode portion 231 is disposed on the cation exchange membrane 21 side using the second cathode electrode portion 232 made of at least one metal of copper, gold or aluminum, the cation exchange membrane 21 The contact potential difference of the cation exchange membrane 21 is prevented by sandwiching the both sides of the same material between the material having the ozone generation catalyst function of the anode electrode 22 and the material having the ozone generation catalyst function of the first cathode electrode portion 231. Deterioration of the cation exchange membrane 21 can be prevented. And ozone water can be produced | generated by a lower voltage. In particular, when a platinum-coated metal is used for the anode electrode 22 or the first cathode electrode portion 231, it can be suppressed at a lower cost than when pure platinum is used.
Further, as the cathode electrode 23, in addition to the first cathode electrode portion 231 made of a material having an ozone generation catalyst function, a second cathode electrode portion 232 made of at least one metal of silver, copper, gold or aluminum is used. Therefore, the electrical conductivity on the cathode electrode 23 side can be significantly increased by the highly conductive metal, and the ozone water generation efficiency can be further increased.
Further, the mass or surface area of silver, copper, gold or aluminum used for the second cathode electrode part 232 is equal to the mass or surface area of the material having an ozone generation catalyst function used for the first cathode electrode part 231 or By making it larger, the electrical conductivity on the cathode electrode 23 side is further greatly increased, hydrogen ions can be more easily transferred from the anode electrode 22 to the cathode electrode 23, and purified water having a low electrical conductivity is used as raw water. Can also produce highly concentrated ozone water.

表１の結果より、陰極電極に白金のみを使用する場合より、白金と銀を重ねて使用することによって陽極電極におけるオゾンの生成を促進しオゾン水濃度を上げることができる。さらに表１の結果から、白金がなければオゾン水を得られないということはないが、水道水、精製水のいずれの場合も、白金が存在することにより低い電圧でオゾン水を生成することができる。また、陰極電極における白金の役割としては、陽イオン交換膜の接触電位差を防ぐという目的もある。 [Example]
Next, the following experiment was performed on the present invention to clarify the effect of the material used for the cathode electrode.
(Role of platinum as cathode electrode)
The cation exchange membrane used was a DuPont naphthion membrane, the anode electrode used solid platinum micro-grating, and the cathode electrode shown in Table 1 was used. Then, a catalyst electrode in which the cation exchange membrane, the anode electrode and the cathode electrode are overlapped and press-contacted is arranged at a predetermined position in the container as shown in FIG. 1, and tap water (water temperature 25 ° C., conductivity is introduced from the inflow path). 165 μS / cm) was supplied, and each value of DC voltage shown in Table 1 was applied between the anode electrode and the cathode electrode, and ozone water was obtained from the outflow path. The concentration of ozone water at this time is shown in Table 1. Similarly, purified water (water temperature 25 ° C., conductivity 1.92 μS / cm) was supplied instead of tap water to generate ozone water, and the concentration of the generated ozone water is shown in Table 1.

From the results shown in Table 1, it is possible to promote the generation of ozone in the anode electrode and increase the concentration of ozone water by using platinum and silver in an overlapping manner, compared with the case where only platinum is used for the cathode electrode. Furthermore, from the results of Table 1, ozone water cannot be obtained without platinum, but in both cases of tap water and purified water, ozone water can be generated at a low voltage due to the presence of platinum. it can. Also, the role of platinum in the cathode electrode is to prevent contact potential difference of the cation exchange membrane.

表２の結果より、陰極電極に銀の質量を増やしていくことにより、明らかにオゾン水の濃度が高くなり、オゾン水生成が促進されることが認められる。 (The role of silver in the cathode electrode)
The cation exchange membrane used was a DuPont naphthion membrane, the anode electrode used solid platinum micro-grating, and the cathode electrode shown in Table 2 was used. Then, a catalyst electrode in which the cation exchange membrane, the anode electrode and the cathode electrode are overlapped and press-contacted is arranged at a predetermined position in the container as shown in FIG. 1, and tap water (water temperature 25 ° C., conductivity is introduced from the inflow path). 165 μS / cm) was supplied, and each value of DC voltage shown in Table 2 was applied between the anode electrode and the cathode electrode, and ozone water was obtained from the outflow path. The concentration of ozone water at this time is shown in Table 2. Similarly, purified water (water temperature 25 ° C., conductivity 1.92 μS / cm) was supplied instead of tap water to generate ozone water, and the concentration of the generated ozone water is shown in Table 2.

From the results in Table 2, it can be seen that increasing the mass of silver in the cathode electrode clearly increases the concentration of ozone water and promotes the generation of ozone water.

表３の結果より、陰極電極を白金と銅の組み合わせにすることによっても、銀を使用する場合より劣るもののオゾン水を得られることが認められ、白金のみを使用する場合に比して明らかにオゾン水生成効率が上がることがわかる。 (The role of copper in the cathode electrode)
The cation exchange membrane used was a DuPont naphthion membrane, the anode electrode used solid platinum micro-grating, and the cathode electrode shown in Table 3 was used. Then, a catalyst electrode in which the cation exchange membrane, the anode electrode and the cathode electrode are overlapped and press-contacted is arranged at a predetermined position in the container as shown in FIG. 1, and tap water (water temperature 25 ° C., conductivity is introduced from the inflow path). 160 μS / cm) was supplied, and each value of DC voltage shown in Table 3 was applied between the anode and cathode, and ozone water was obtained from the outflow path. The concentration of ozone water at this time is shown in Table 3. Similarly, purified water (water temperature 25 ° C., conductivity 165 μS / cm) was supplied instead of tap water to generate ozone water. Table 3 shows the concentration of ozone water.

From the results in Table 3, it is recognized that even when the cathode electrode is a combination of platinum and copper, ozone water can be obtained although it is inferior to the case of using silver, as compared with the case of using only platinum. It can be seen that the ozone water generation efficiency increases.

表４の結果より、陰極電極に白金メッキを施したものを使用した場合も無垢の白金ほどではないが、オゾン生成に効果が得られることが認められる。白金メッキはチタンのマイクログレーチングの母材に厚さ２μｍの白金メッキを施したもので、厚さと形状からこれを重量で表示すると約０．０５２grとなり、無垢の白金の約１０分の１の質量となる。母材のチタンは極めて電気伝導度の低い材質であるから、この場合は表面積が支配的になると考えられる。 (Role of platinum plating of cathode electrode)
The cation exchange membrane used was a DuPont naphthion membrane, the anode electrode used solid platinum micro-grating, and the cathode electrode shown in Table 4 was used. Then, a catalyst electrode in which the cation exchange membrane, the anode electrode and the cathode electrode are overlapped and press-contacted is arranged at a predetermined position in the container as shown in FIG. 1, and tap water (water temperature 25 ° C., conductivity is introduced from the inflow path). 165 μS / cm) was supplied, and each value of DC voltage shown in Table 2 was applied between the anode electrode and the cathode electrode, and ozone water was obtained from the outflow path. The concentration of ozone water at this time is shown in Table 4. Similarly, purified water (water temperature 25 ° C., conductivity 1.92 μS / cm) was supplied instead of tap water to generate ozone water, and the concentration of the generated ozone water is shown in Table 4.

From the results in Table 4, it can be seen that even when the cathode electrode is subjected to platinum plating, it is not as effective as pure platinum, but it is effective for generating ozone. Platinum plating is a titanium micro-grating base material with a platinum plating thickness of 2μm. When expressed in weight from the thickness and shape, it is about 0.052gr, which is about one-tenth the mass of pure platinum. It becomes. Since the base material titanium is a material with extremely low electrical conductivity, it is considered that the surface area becomes dominant in this case.

  As is clear from the results of Tables 1 to 4 above, platinum or a platinum-coated metal is used for the anode electrode, platinum or a platinum-coated electrode is used on the cation exchange membrane side of the cathode electrode, and the conductivity is higher. By using silver or copper in layers, it is possible to prevent deterioration of the cation exchange membrane and to generate ozone water at a low voltage. Moreover, the electrical conductivity in the cathode electrode can be increased, and high-concentration ozone water can be generated. As a result, high-concentration ozone water can be easily generated even if purified water with low conductivity is used as raw water. it can.

1 is a longitudinal sectional view schematically showing an outline of an ozone water generating device 100. FIG.

Explanation of symbols

2 Catalytic electrode 21 Cation exchange membrane 22 Anode electrode 23 Cathode electrode 100 Ozone water generator 231 First cathode electrode part 232 Second cathode electrode part

Claims (3)

A catalyst electrode is formed by pressing an anode electrode on one surface of a cation exchange membrane and pressing a cathode electrode on the other surface, a DC voltage is applied between the anode electrode and the cathode electrode, and the anode In the ozone water generator that generates ozone water by bringing the raw material water into contact with the electrode,
Using a material having an ozone generation catalyst function for the anode electrode,
The cathode electrode includes a first cathode electrode portion made of a material having the ozone generation catalyst function, and a second cathode electrode portion made of at least one metal of silver, copper, gold or aluminum, One cathode electrode part is disposed on the cation exchange membrane side ,
The ozone water generating apparatus , wherein the mass or surface area of the second cathode electrode part is equal to or greater than the mass or surface area of the first cathode electrode part .   The ozone water generating apparatus according to claim 1, wherein the material having an ozone generation catalytic function is platinum, gold, or a coating metal thereof. The ozone water generator according to claim 1 or 2 , wherein silver, copper, gold or aluminum used for the second cathode electrode part is silver, copper, gold or aluminum having a silver chloride layer. .

Images