JPH11114564A - Electrolyzed water producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the electrolyzed water having the same available chlorine concn. as the conventional one with the less consumption of power. SOLUTION: The raw water contg. chlorine ion is supplied to the electrolytic cell 1 provided with an anode plate 5 and a cathode plate 6 with an ion- permeable diaphragm 2 in between and electrolyzed, and the electrolytic water contg. available chlorine is generated on the anode side 4 of the cell 1. An electrode catalyst consisting of three components, i.e., platinum oxide, iridium oxide and ruthenium oxide, is deposited on the surface of a titanium substrate to constitute the anode plate 5. The electrode catalyst contains 5-20 mol.% ruthenium oxide and 50-80 mol.% platinum oxide. The titanium substrate is meshy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic cell provided with an anode plate and a cathode plate through an ion-permeable diaphragm, to supply raw water containing chlorine ions for electrolysis, and to perform electrolysis on the anode side of the electrolytic cell. The present invention relates to an electrolyzed water generation device that generates electrolyzed water containing chlorine compounds such as residual chlorine and hypochlorous acid as available chlorine.

[0002]

2. Description of the Related Art An electrolytic cell is divided into an anode chamber and a cathode chamber by an ion-permeable membrane such as an ion-exchange membrane, and an electrode is provided in each chamber. BACKGROUND ART An electrolyzed water generating apparatus provided with a plate is known.

[0003] The electrolyzed water generator supplies raw water to which chlorides such as sodium chloride and potassium chloride are added to the respective chambers, and conducts electricity between the anode plate and the cathode plate to perform electrolysis. From the anode chamber, acidic electrolyzed water containing chlorine and chlorine compounds such as hypochlorous acid is obtained, but the amount of these substances is expressed as an effective residual chlorine concentration, which is one indicator of the bactericidal effect. I have. On the other hand, alkaline electrolyzed water is obtained from the cathode chamber. Since the acidic electrolyzed water containing available chlorine has a bactericidal effect, it is used for general disinfection, disinfection, and deodorization, and is used for disinfecting pathogens by spraying on soil, crops and flowers in agriculture or horticulture. .

In the electrolyzed water generating apparatus, an electrode made of a titanium base material has been used in order to prevent the corrosion of the electrode, particularly the anode plate, due to a chlorine compound. Also,
In the electrolyzed water generator, an electrode is used in which an electrode catalyst composed of two components, platinum oxide and iridium oxide, is supported on the surface of the titanium substrate in order to reduce the power consumed for electrolysis.

However, if a large amount of electrolyzed water is generated or the effective chlorine concentration in the electrolyzed water is to be increased, a large amount of electrolysis energy is required even for the electrode carrying the electrode catalyst, and the electrode is consumed for electrolysis. There is a disadvantage that power increases. In order to increase the residual chlorine concentration, it is conceivable to increase the amount of chloride added to the raw water.However, the chloride reacts only partly by electrolysis to make available chlorine such as hypochlorous acid. Is generated, and the others remain in the electrolytic water generated as chlorides. Therefore, if such spraying of the electrolytic water is repeated, there is a concern that the sprayed material may be adversely affected. For example, it may be a factor that corrodes metals, or may cause physiological disorders of plants in agriculture or horticulture.

[0006]

An object of the present invention is to provide an electrolyzed water generating apparatus which can solve such inconvenience and can obtain electrolyzed water having the same effective chlorine concentration as the conventional one with less power consumption. Aim.

[0007]

In order to achieve the above object, an electrolyzed water generating apparatus according to the present invention includes chlorine ions in an electrolytic cell provided with an anode plate and a cathode plate via an ion-permeable diaphragm. In an apparatus for supplying raw water to perform electrolysis and generating electrolyzed water containing effective chlorine on the anode side of the electrolytic cell, the anode plate is formed from platinum oxide, iridium oxide, and ruthenium oxide on the surface of a titanium base material. Characterized by supporting an electrode catalyst. Here, the electrode catalyst is formed by heat-treating a platinum compound, an iridium compound and a ruthenium compound in the air, but not all of the platinum compound is an oxide. This shows a mixed state. Therefore, in this specification, the term “platinum oxide” means a state in which platinum and an oxide of platinum are mixed as described above.

When the raw water is electrolyzed in the electrolytic cell having the above structure, an oxidation reaction of water and an oxidation reaction of chlorine ions occur on the anode side. The two reactions usually occur simultaneously because the oxidation-reduction potential is close in electrolysis. Therefore, in the apparatus of the present invention, by using an electrode carrying the above-described three-component electrode catalyst, an oxidation reaction of chlorine ions is more likely to occur than in a conventional electrode. That is, the three-component electrode catalyst plays a role in reducing the reaction overvoltage in the oxidation of chlorine ions.
As a result, hypochlorite, which is a reaction product of oxidation of chloride ions, consumes less power than a conventional electrode in which a two-component electrode catalyst of platinum oxide and iridium oxide is supported on the surface of a titanium base material. Can be increased, and electrolyzed water having an increased effective chlorine concentration can be obtained.

Further, in the electrolyzed water generator water of the present invention, the electrode catalyst contains ruthenium oxide in an amount of 5 to 20 mol%.
Is included in the range. When the content of ruthenium oxide in the three components constituting the electrode catalyst is less than 5 mol%, the effect of prioritizing the oxidation reaction of chloride ions cannot be sufficiently obtained, and even when the content exceeds 20 mol%, the oxidation reaction of chloride ions does not occur. The effect of giving priority over it cannot be expected.

[0010] In the electrolyzed water generator according to the present invention, the electrode catalyst contains platinum oxide in a range of 50 to 80 mol%. Constituting the electrode catalyst 3
When the content of platinum oxide in the components is less than 50 mol%, the conductivity of the electrode catalyst increases, and when the content exceeds 80 mol%, the contents of the other two components relatively decrease, and the oxidation reaction of chlorine ions occurs. May not be sufficiently effective.

In the electrolyzed water generating apparatus according to the present invention, the titanium base material constituting the anode plate may be flat, but has a large surface area as compared with the flat plate, and the chemical species generated on the electrode surface is small. The mesh shape is preferred because it is easy to diffuse.

[0012]

Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is an explanatory cross-sectional view showing one configuration example of the electrolyzed water generation device of the present embodiment, and FIG. 2 is a histogram showing the results of the example and the comparative example.

As shown in FIG. 1, the electrolytic water generating apparatus of this embodiment divides an electrolytic cell 1 into an anode chamber 3 and a cathode chamber 4 by an ion-permeable membrane 2 such as an ion exchange membrane. By disposing electrodes in the chamber, the anode plate 5 can be
And a cathode plate 6. The anode plate 5 and the cathode plate 6 are connected to an external power source (not shown) by lead terminals 5a and 6a which penetrate the side wall of the electrolytic cell 1 and are guided to the outside. Raw water supply conduits 7 and 8 are connected to the bottoms of the anode chamber 3 and the cathode chamber 4, respectively, and electrolytic water extraction conduits 9 and 10 are connected to the upper part.

In the electrolyzed water generating apparatus of the present embodiment, the anode plate 5 has a mesh-like titanium substrate on which an electrode catalyst composed of three components of platinum oxide, iridium oxide and ruthenium oxide is supported. For the cathode plate 6, a mesh-shaped titanium substrate that does not support the electrode catalyst is used.

The electrode catalyst is prepared by, for example, applying a coating solution obtained by dissolving a platinum compound, an iridium compound and a ruthenium compound in a predetermined ratio in an alcohol-based organic solvent as a solvent on a mesh-shaped titanium substrate. By drying in air and baking at a temperature in the range of 700 to 800 ° C. for 1 to 3 hours, it can be sintered on the titanium substrate. By repeatedly applying, drying, and sintering the coating solution, the electrode catalyst can obtain a relatively uniform coating layer and a necessary amount of catalyst to be supported. The platinum compound, the iridium compound and the ruthenium compound include platinum,
A complex of iridium or ruthenium chloride or the like can be used.

In the electrolyzed water generating apparatus of this embodiment, raw water containing chlorine ions is introduced into the anode chambers 3 and the cathode chamber 4 from the raw water supply conduits 7 and 8, and a predetermined current is supplied between the anode plate 5 and the cathode plate 6. The electrolysis is performed by energizing. Then, the electrolyzed water obtained in the anode chamber 3 and the cathode chamber 4 is taken out from the electrolyzed water extraction conduits 9 and 10, respectively.

The water usually contains various ions such as chlorine ions, except for those subjected to artificial special operations such as distilled water. Therefore, in the present invention, any water such as city water, industrial water, well water and the like can be adopted as the raw water, and can be used for the electrolysis. The raw water is preferably added with an electrolyte in order to perform the electrolysis satisfactorily. Since the electrolyte serves as a supply source of the chloride ion, a chloride such as sodium chloride (NaCl) or potassium chloride (KCl) is used. It is preferable to use

When electrolysis is performed using the raw water, the anode chamber 3
In this case, oxygen (O ₂ ) is generated by electrolysis of water to generate hydrogen ions (H ⁺ ), and at the same time, chlorine ions (Cl ⁻ ) contained in the raw water are oxidized to generate chlorine (Cl ₂ ). Part of the chlorine is vaporized and released out of the system, but part of the chlorine is dissolved in water to generate a chlorine compound (including ions) such as hypochlorous acid. The reaction at the anode is shown by the following formula. still,
Oxygen generated by water electrolysis is released as a gas outside the system.

[0019]

Embedded image

Although the reactions of the above formulas (1) and (2) are reactions that occur competitively, in the anode chamber 3 of the present embodiment, since the electrode catalyst of the above configuration is supported on the anode plate 5, The reaction of the formula (2) is more likely to occur as compared to the conventional electrode, and the reaction of hypochlorous acid (HCl) is performed according to the formulas (3) to (5).
O), ClO ^-, Cl ^- or the like is generated, a high effective chlorine concentration electrolytic water is obtained.

Further, in the cathode chamber 4, the predominantly hydrogen is generated by electrolysis of water, hydroxide ions (OH ^-)
Is generated. The reaction in the cathode chamber 4 is shown by the following equation.

[0022]

Embedded image

As a result, the electrolytic water extraction conduit 9 on the anode chamber 3 side
Can obtain acidic water having a high effective chlorine concentration, and alkaline water can be obtained from the electrolytic water extraction conduit 10 on the cathode chamber 4 side.

Since the anode chamber 3 and the cathode chamber 4 are separated from each other by the ion-permeable diaphragm 2, electric charges can move to each other, but the acidic water and the alkaline water do not mix with each other. Here, the diaphragm 2 may have any shape such as a woven fabric, a nonwoven fabric, and a plastic film (polymer film), and may have physical voids or pores or a solid electrolyte membrane. A device having a function of transmitting and moving charges is used. Examples of the material having the physical voids or pores include polymer films such as polypropylene and polyethylene having micropores (for example, polyolefin porous film “UPORE (trademark)” manufactured by Ube Industries, Ltd.), natural fibers and artificial fibers. And a nonwoven fabric formed into a film by combining the two. As a typical example, an ion exchange membrane can be given as a device having a function of transmitting and moving charges.

At the time of the electrolysis, hydroxides such as caustic soda (NaOH) and caustic potash (KOH) are generated in the cathode chamber 4 from chlorides such as sodium chloride and potassium chloride contained in the raw water. Is strongly alkaline, the diaphragm 2 is preferably an ion exchange membrane having acid resistance and alkali resistance. Examples of such an ion exchange membrane include Nafion 117 (trade name) manufactured by DuPont.

Next, examples and comparative examples of the present invention will be described.

[0027]

Example 1 A platinum compound, an iridium compound and a ruthenium compound were added to an alcoholic organic solvent by Pt / Ir / Ru.
= 7/2/1 (molar ratio) to prepare a coating solution, apply the coating solution on a mesh-shaped titanium substrate, and dry the coating solution.
At a temperature of 1 to 3 hours. Thereby, on the titanium substrate, platinum oxide, iridium oxide and ruthenium oxide were added.
An electrode was produced by sintering and supporting an electrode catalyst containing components in a ratio of about 7/2/1.

In the apparatus for generating electrolyzed water shown in FIG. 1, the above-mentioned electrode is used as the anode plate 5, the mesh-shaped titanium substrate not supporting the electrode catalyst is used as the cathode plate 6, and the raw water supply conduit 7,
Raw water containing 0.8 g / liter of sodium chloride from 8 is introduced into the anode chamber 3 and the cathode chamber 4 at a flow rate of 0.5 liter / minute, and a predetermined current is supplied between the anode plate 5 and the cathode plate 6. And electrolysis water extraction conduit 9 on the anode chamber 3 side.
To obtain electrolyzed water containing an effective chlorine concentration of 50 ppm (50 mg / liter).

At this time, the power consumption was 42.5 W. The results are shown in FIG.

[0030]

Example 2 A coating solution was prepared so that Pt / Ir / Ru = 7/1/2, and the coating solution was applied on a mesh-shaped titanium substrate, dried, fired, and oxidized on the titanium substrate. An electrode was prepared by sintering and supporting an electrode catalyst containing three components of platinum, iridium oxide and ruthenium oxide in a ratio of about 7/1/2, and the above-mentioned electrode was used as the anode plate 5. Perform electrolysis in the same manner as 1
Effective chlorine concentration 50p from electrolytic water outlet conduit 9 on anode chamber 3 side
pm (50 mg / liter) was obtained.

At this time, the power consumption was 152.3 W. The results are shown in FIG.

[0032]

Example 3 A coating solution was prepared so that Pt / Ir / Ru = 7 / 2.5 / 0.5, and the coating solution was applied to a mesh-shaped titanium substrate, dried and fired, An electrode is manufactured by sintering and supporting an electrode catalyst containing three components of platinum oxide, iridium oxide and ruthenium oxide at a ratio of about 7 / 2.5 / 0.5 on a substrate, and the electrode is formed on an anode plate. Electrolysis was performed in the same manner as in Example 1 except that the sample was set to 5, and electrolyzed water containing an effective chlorine concentration of 50 ppm (50 mg / liter) was obtained from the electrolyzed water extraction conduit 9 on the anode chamber 3 side.

At this time, the power consumption was 73.9 W. The results are shown in FIG.

[0034]

Example 4 A coating solution was prepared so that Pt / Ir / Ru = 7 / 1.5 / 1.5, and the coating solution was applied on a mesh-shaped titanium substrate, dried, and fired. An electrode is manufactured by sintering and supporting an electrode catalyst containing three components of platinum oxide, iridium oxide and ruthenium oxide at a ratio of about 7 / 1.5 / 1.5 on a substrate, and the electrode is formed on an anode plate. Electrolysis was performed in the same manner as in Example 1 except that the sample was set to 5, and electrolyzed water containing an effective chlorine concentration of 50 ppm (50 mg / liter) was obtained from the electrolyzed water extraction conduit 9 on the anode chamber 3 side.

At this time, the power consumption was 47.9 W. The results are shown in FIG.

[0036]

Comparative Example 1 Electrolysis was carried out in the same manner as in Example 1 except that an electrode in which an electrode catalyst consisting of only platinum oxide was supported on a mesh-shaped titanium substrate was used as an anode plate 5. Effective chlorine concentration 50ppm (50m
g / liter).

At this time, the power consumption was 459.0 W. The results are shown in FIG.

[0038]

COMPARATIVE EXAMPLE 2 An anode plate 5 was used except that an electrode in which an electrode catalyst containing two components of platinum oxide and iridium oxide in a ratio of 8/2 (molar ratio) was supported on a mesh-shaped titanium substrate was used. Electrolysis was performed in the same manner as in Example 1, and the effective chlorine concentration was 50 ppm (50 mg) from the electrolytic water extraction conduit 9 on the anode chamber 3 side.
/ Liter).

At this time, the power consumption was 267.5 W. The results are shown in FIG.

[0040]

Comparative Example 3 An anode plate 5 was used except that an electrode in which an electrode catalyst containing two components of platinum oxide and iridium oxide in a ratio of 6/4 (molar ratio) was supported on a mesh-shaped titanium substrate was used. Electrolysis was performed in the same manner as in Example 1, and the effective chlorine concentration was 50 ppm (50 mg) from the electrolytic water extraction conduit 9 on the anode chamber 3 side.
/ Liter).

At this time, the power consumption was 270.6 W. The results are shown in FIG.

[0042]

Comparative Example 4 An anode plate 5 was used, except that an electrode in which an electrode catalyst containing two components of platinum oxide and iridium oxide in a 7/3 ratio (molar ratio) was supported on a mesh-shaped titanium substrate was used. Electrolysis was performed in the same manner as in Example 1, and the effective chlorine concentration was 50 ppm (50 mg) from the electrolytic water extraction conduit 9 on the anode chamber 3 side.
/ Liter).

At this time, the power consumption was 269.0 W. The results are shown in FIG.

FIG. 2 shows that according to each embodiment of the present invention in which the electrode carrying the electrode catalyst composed of three components of platinum oxide, iridium oxide and ruthenium oxide was used as the anode plate 5, only platinum oxide or platinum oxide or It is clear that the electrolyzed water can be obtained with significantly lower power consumption as compared with the comparative examples in which the electrode supporting the electrode catalyst composed of two components of iridium oxide was used as the anode plate 5.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing one configuration example of an electrolyzed water generation device of the present invention.

FIG. 2 is a histogram showing the results of Examples and Comparative Examples.

[Explanation of symbols]

Reference numeral 1 denotes an electrolytic cell, 2 denotes a diaphragm, 5 denotes an anode plate, and 6 denotes a cathode plate.

Claims (4)

[Claims] 1. An electrolytic cell provided with an anode plate and a cathode plate through an ion-permeable diaphragm, is supplied with raw water containing chlorine ions to perform electrolysis, and electrolytic water containing effective chlorine is provided on the anode side of the electrolytic cell. An electrolyzed water generating apparatus, wherein the anode plate has an electrode catalyst comprising three components of platinum oxide, iridium oxide and ruthenium oxide supported on a surface of a titanium base material. 2. The method according to claim 1, wherein the electrode catalyst comprises ruthenium oxide in an amount of 5-2.
2. The electrolyzed water generator according to claim 1, wherein the content is in the range of 0 mol%. 3. The apparatus for producing electrolyzed water according to claim 1, wherein the electrode catalyst contains platinum oxide in a range of 50 to 80 mol%. 4. The apparatus for producing electrolyzed water according to claim 1, wherein the titanium base material has a mesh shape.