JP2002080986A - Electrode for ozone generation, ozonized water manufacturing method and ozonized water manufacturing apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ozone forming electrode which is capable of sterilizing and cleaning potable water and food safely to the human body by efficiently and inexpensively manufacturing ozonized water of a high concentration and high purity and preventing the contamination of the water to be treated by eluted metal in a manufacturing process and an ozonized water manufacturing method and apparatus featuring compactness, excellent maintenance characteristic, ease of maintenance and management, and excellent energy saving characteristic by using the ozone forming electrode. SOLUTION: This electrode for ozone generation is constituted by having an electrode base material 16 which is formed of a porous body or net-like body and an electrode catalyst 17 which contains a composite composition consisting of either one of the oxide of platinum group metals and an alloy containing the platinum group metals and coats the electrode base material 16 described above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ozone generating electrode for generating ozone having an action of cleaning and sterilizing food, water, and the like, an ozone producing method using the same, and an ozone producing apparatus.

[0002]

2. Description of the Related Art Known methods for generating ozone include a method using ultraviolet irradiation, a method using discharge, and a method using water electrolysis.

[0003] The ozone generation method by ultraviolet irradiation can make the configuration of the ozone generator relatively simple as compared with other methods, but the required power per kg of ozone is 550 kWh /.
kg-O ₃ compared to other methods (20 kWh / k by the discharge method)
g-O _3, are said to be 60kWh / kg-O ₃ about by electrolysis) has the disadvantage that large.

The method of generating ozone by electric discharge is the method which requires the lowest power per kg of ozone generated and has the highest ozone generation efficiency among the above-mentioned ozone generation methods, and is therefore applied to an industrial ozone generator. ing. However, in the ozone generation by the discharge method, when dissolving ozone in water for use, it is necessary to perform an operation of bringing the generated ozone into gas-liquid contact and dissolving it in a liquid phase, so that it is inevitable that the operation becomes complicated and troublesome. . In addition, air is usually used as a raw material gas to reduce the cost of ozone production.
However, since the nitrogen molecules contained in the air are oxidized to generate nitric acid, the generated ozone water has a strong acidity, which causes a problem that the ozone water cannot be used for corrosive use of the apparatus or for sterilizing and cleaning drinking water. In order to solve such a problem, a method of removing moisture in the air before discharging and a method of removing generated nitrogen oxides have been proposed (Japanese Patent Laid-Open No. 7-330310). When air is used as the raw material gas, the partial pressure of the generated ozone is low because nitrogen occupies about 80% of the volume in the air, and the dissolved amount of the gas is proportional to the partial pressure of the gas. It is difficult to obtain high-concentration ozone water because its dissolution amount is small.

[0005] The ozone generation method by electrolysis of water is an excellent ozone generation method because a relatively high concentration of ozone water can be easily obtained.

In general, one of the characteristics of the sterilization treatment using ozone is the so-called all or n sterilization effect of ozone.
As is called one effect, the ozone works completely when the required amount of ozone is sufficient, but has little effect when the amount of ozone is insufficient. Escherichia coli which is a representative indicator bacterium has 2-3 pp
m concentration of ozone water is required. Therefore, ozone must be dissolved at a high concentration in order to use it for sterilization and washing of drinking water and foods. Therefore, a water electrolysis method is desirable as a means for producing high-concentration ozone water. In addition, the ozone generation by the electrolysis method does not cause a significant change in the pH of the generated ozone water with respect to the pH of the raw water and does not require a complicated gas-liquid contact device, so the ozone generation method is clean and does not require complicated labor. You can say that.

[0007] With respect to a method of generating ozone by electrolysis of water having such characteristics, the following techniques are known.

(1) JP-A-5-255879 (hereinafter referred to as "A") discloses that a catalyst is unevenly distributed on the side of an ion-exchange membrane as a cathode of an electrode structure formed by closely adhering a cathode, an ion-exchange membrane and an anode. An apparatus for efficiently producing high-concentration and high-purity ozone with low power consumption by performing electrolysis while using a gas electrode and supplying ion-exchanged water to the anode side and oxygen gas to the cathode side is shown. I have. In this technique, a catalyst prepared by electrodeposition of β-PbO ₂ is used as an anode electrode catalyst.

(2) Japanese Patent No. 2,840,753 (hereinafter referred to as “B”) discloses a method of producing ozone by water electrolysis using a perfluorosulfonate-type cation exchange resin membrane, wherein the platinum-coated side has a cathode of a cation exchange membrane. A method for producing ozone by zero-gap electrolysis using a lead dioxide electrode as the anode while pressing against the side is shown.

(3) Japanese Patent Application Laid-Open No. 8-134677 (hereinafter referred to as "C") discloses that treated water is electrolyzed by passing it between an electrode and a precious metal lath net, and the generated ozone mixed bubbles are changed in a flow path. And an eddy current are used to dissolve ozone in water as much as possible by drawing ozone into water immediately after generation.

[0011]

The above-mentioned conventional method has the following problems.

(1) In the ozone electrolytic production method using a lead dioxide electrode described in JP-A-B and JP-B-B2, the lead dioxide (β-PbO ₂ ) used is harmful as specified in the Water Pollution Control Law. Since it is a substance, there is a problem that it cannot be used for washing and sterilizing drinking water and foods which are directly taken into the human body.

(2) In order to use ozone water produced by such a method for continuous aeration, ozone is once separated from the liquid phase by a gas-liquid separator, and the ozone is dissolved in the aqueous phase again by using a gas-liquid contactor. Need. For this reason, the great advantage of the electrolysis method that high-concentration ozone can be easily generated is lost, and there is a disadvantage that the processing operation is complicated, and labor and cost are required.

(3) In the ozone generator described in Japanese Patent Application Laid-Open Publication No. H07-76, in which treated water passes between noble metal lath nets, the gas generated at the anode stays between the electrodes and the lath net due to the complicated flow path. As a result, there is a problem that the resistance between the electrodes is increased, and the current efficiency is reduced.

The present invention has been made to solve the conventional problems, and efficiently and inexpensively produces high-concentration, high-purity ozone water, and prevents human water from being contaminated by the elution metal during the production process. It is an object of the present invention to provide an ozone generation electrode that is safe and capable of sterilizing and washing drinking water and food, and to provide an ozone water production method and an ozone water production apparatus that are compact and excellent in maintainability and energy saving.

[0016]

According to the present invention, there is provided an ozone generating electrode comprising a porous or reticulated electrode substrate, an oxide of a platinum group element and a platinum group element. And an electrode catalyst that covers the electrode base material, including a composite composition comprising any one of the alloys including:

According to this configuration, ozone water of high concentration and high purity is efficiently and inexpensively produced, and contamination of the water to be treated by the eluting metal is prevented in the production process, so that it is safe for the human body and sterilization and washing of drinking water and food. Can be provided.

Further, the method for producing ozone water using the electrode for ozone generation of the present invention comprises an anode having the electrode for ozone generation according to any one of claims 1 to 3, and an electrode catalyst formed on a gas diffusion material. Between the cathode, a cation exchange membrane is disposed in contact with the respective electrode catalyst surfaces of both electrodes, so that ozone is generated by an electrochemical reaction of water supplied by supplying electricity to the anode and the cathode. It is configured.

With this configuration, it is possible to provide a method for producing ozone water which is compact, easy to maintain and maintain, and excellent in energy saving.

The apparatus for producing ozone water according to the present invention is characterized in that:
3. An anode provided with the ozone generating electrode according to any one of 3., a cathode having an electrode catalyst formed on a gas diffusion material, and abutting and bonding to the respective electrode catalyst surfaces of the anode and the cathode. A cation exchange membrane, an anode jacket for holding an anode chamber in which the anode is arranged, a cathode jacket for holding a cathode chamber in which the cathode is arranged, and contact with the respective collector terminals of the anode jacket and the cathode jacket. A supply unit for passing a gas and treated water provided on a surface to be treated, an electrolytic cell formed by fastening the anode jacket and the cathode jacket to each other, and a voltage applying unit for passing a direct current between electrodes of the electrolytic cell. It is comprised including.

With this configuration, the ozone generating electrode is used, and it is compact, excellent in maintenance, easy in maintenance,
An ozone water production method excellent in energy saving can be provided.

[0022]

DETAILED DESCRIPTION OF THE INVENTION The electrode for ozone generation according to the first aspect of the present invention includes an electrode substrate formed of a porous or reticulated body and an alloy containing a platinum group element oxide and a platinum group element. And an electrode catalyst that covers the electrode base material and includes the composite composition of any one of the above.

The following effects are obtained by this configuration.

(A) Since the electrode catalyst is formed on the electrode substrate formed of a porous body or a mesh body, the area of contact with the water to be treated can be increased to increase the concentration of ozone generated. At the same time, high-purity ozone is obtained.

(B) Since harmful metals such as lead dioxide do not elute in the environment, highly safe ozone water can be produced. In addition, such a harmful component removal process can be omitted, and the processing apparatus can be configured inexpensively and compactly.

(C) The power required for ozone generation is reduced, and ozone water can be produced at low processing cost.

(D) Since high-concentration ozone water can be supplied, Escherichia coli, which is a representative indicator bacterium, can be efficiently sterilized, and the safety of drinking water and food can be effectively improved.

(E) In the production of ozone water by the electrolytic method,
The pH of the generated ozone water does not significantly change the pH of the raw water.

(F) Since a complicated gas-liquid separation and gas-liquid contacting device is not required, the processing device can be configured inexpensively and compactly.
In addition, labor and cost can be saved.

Here, among the elements belonging to groups 8 to 10 of the periodic table, the platinum group elements refer to six elements of ruthenium Ru, rhodium Rh, palladium Pd, osmium Os, iridium Ir and platinum Pt. These platinum group elements have characteristics such as high density as a simple substance (> 12 g / cm ³ ) and poor chemical reactivity.

As the electrode substrate formed of a porous or reticulated body, a reticulated body made of a metal such as titanium, platinum, copper, niobium, gold, neodymium, or zirconium, or a porous body can be used.

When a porous body is used, its porosity is 2
It is desirable to set it in the range of 0 to 70%, preferably 55 to 65% for the following reasons. That is, as the porosity becomes smaller than 55%, the contact area with the treated water becomes smaller, so that the efficiency of the electrolysis is lowered and it becomes difficult to generate a high concentration of ozone. %, The strength of the electrode material becomes insufficient and the durability tends to decrease as the ratio exceeds 50%, and these tendencies become more remarkable when the porosity is less than 20% or exceeds 70%. .

According to a second aspect of the present invention, in the ozone generating electrode according to the first aspect, the composite composition has a composition in which a part of a platinum group atom is substituted with a trivalent metal atom. ing.

As a result, the following operation can be obtained in addition to the operation of the first aspect.

(A) The trivalent metal atom partially substituted with a platinum group atom activates the electrode, so that the hydroxyl group generated by the water splitting in the anodic oxidation is easily captured by the electrode. Can do well.

(B) A desired electrode characteristic can be imparted by adjusting the replacement operation of the trivalent metal atom by the ratio of the metal in the plating solution of the electrode base material, and the electrode can be made compact to save energy. It is possible to provide an excellent electrode for ozone generation.

The third aspect of the present invention is the first or second aspect.
Wherein the trivalent metal atom is at least one element selected from the group consisting of vanadium, chromium, cobalt, iron, yttrium, lanthanum, and bismuth.

According to this configuration, the following operation can be obtained in addition to the operation of the first or second aspect.

(A) Vanadium, chromium, cobalt,
The addition of iron, yttrium, lanthanum, and bismuth to the platinum group element makes it easier to react with the captured hydroxyl groups and oxygen, making it easier to generate ozone at a lower electrode potential, thereby enabling energy saving in ozone generation. It has the action of:

(B) By changing the kind, content, composition ratio, etc. of these elements, the electrode characteristics are changed, and an ozone generating electrode having a predetermined electrode potential can be obtained.
Therefore, it is possible to configure the ozone generation electrode at a low cost by selecting from these elements according to the use situation and the processing cost.

According to a fourth aspect of the present invention, there is provided a method for producing ozone water, comprising the steps of: providing an ozone-generating electrode according to the first to third aspects between an anode having an electrode catalyst formed on a gas diffusion material; A cation exchange membrane is arranged in contact with the respective electrode catalyst surfaces of both electrodes, and is configured to generate ozone by an electrochemical reaction of water supplied by supplying electricity to the anode and the cathode.

As a result, the following effects can be obtained.

(A) Since the cathode has a gas diffusing substance, the gas generated on the surface of the electrode catalyst can be easily discharged to the outside through the continuous ventilation hole. Thereby, the catalyst surface is always activated and a large current can be flowed, and high concentration ozone can be generated quickly, and ozone can be produced with high efficiency.

(B) A part of the gas diffusion material can be formed by a hydrophilic part and the remaining part can be formed by a hydrophobic part. This facilitates the mass transfer of the gaseous substance to the surface of the cathode catalyst. The supply rate of the electrode reactant to the surface is increased, and high-concentration ozone can be generated quickly.

(C) Further, the electrode for water treatment is used as an anode, and the electrode composed of a gas diffusion material and an electrode catalyst is used as a cathode. Since ozone is generated by an electrochemical reaction by applying a direct current to the anode and the cathode, ozone can be produced with high efficiency.

(D) Since the respective electrode catalysts of the anode and the cathode are joined at a predetermined interval via the cation exchange membrane, the cations can be moved through the cation exchange membrane without waste and the efficiency of ozone generation can be improved. be able to.

(E) Since the electrode catalyst is formed on the electrode substrate formed of the porous body or the network, the area of contact with the water to be treated can be increased to increase the concentration of ozone generated. .

(F) Since no harmful metals such as lead dioxide are leached to the environment, highly safe ozone water can be produced. In addition, such a harmful component removal process can be omitted, and the processing apparatus can be configured inexpensively and compactly.

(G) Since high-concentration ozone water can be supplied, Escherichia coli and the like can be efficiently sterilized, and the safety of drinking water and food can be effectively improved.

(H) The pH of the generated ozone water is p
There is no significant change in H and no complicated gas-liquid contact device is required, so no complicated labor is required.

Here, the gas diffusing substance has a continuous ventilation hole or the like for diffusing gas generated by the electrode catalyst to the outside. For example, a part thereof is constituted by a hydrophilic portion such as carbon, Is a sheet-like material having gas permeability such that it is composed of a hydrophobic portion such as polytetrafluoroethylene.

As the cation exchange membrane, a polymer acid or the like in which an acidic group such as a phenolic hydroxy group, a carboxy group, or a sulfone group is bonded to a base synthetic resin such as polystyrene cross-linked with divinylbenzene can be suitably used. The salt of the polymer acid formed by ion exchange is insoluble in water and can remove cations from the aqueous solution.

According to a fifth aspect of the present invention, in the method for producing ozone water according to the fourth aspect, the electrode catalyst of the cathode has a platinum group element.

Thus, the following operation can be obtained in addition to the operation of the fourth aspect.

(A) Since the electrode catalyst is composed of a platinum group element, ozone can be efficiently produced at a low voltage.

(B) Since it does not contain metal components harmful to the environment, highly safe ozone water can be produced.

According to a sixth aspect of the present invention, there is provided an ozone water producing apparatus comprising an anode having the ozone generating electrode according to any one of the first to third aspects, and a gas diffusion material having a communicating hole. A cathode having an electrode catalyst, a cation exchange membrane that abuts and binds to the respective electrode catalyst surfaces of the anode and the cathode, an anode jacket that holds an anode chamber in which the anode is arranged, and an arrangement of the cathode. A cathode jacket that holds a cathode chamber, a supply unit that allows gas and treated water provided on a surface of the anode jacket and the cathode jacket to come into contact with the respective current collecting terminals, and that the anode jacket and the cathode jacket be connected to each other. It is configured to include an electrolytic cell formed by fastening, and a voltage applying unit for flowing a direct current between electrodes of the electrolytic cell.

With this configuration, the following operation is obtained.

(A) Since the anode and the cathode are joined via the cation exchange membrane, it is possible to realize an electrolysis apparatus having a compact apparatus configuration, a low voltage between electrodes, and excellent energy efficiency.

(B) Since the electrode catalyst is formed on the electrode substrate formed of a porous or reticulated body, the concentration of ozone generated can be increased by increasing the contact area with the water to be treated. .

(C) Since the electrode catalyst of the cathode is supported by the gas diffusion material having the communicating holes, the gas generated on the surface of the electrode catalyst can be easily discharged to the outside. Thereby, the catalyst surface is always activated, and high-concentration ozone can be generated efficiently.

(D) Since environmentally harmful metal components such as lead dioxide do not elute, highly safe ozone water can be produced. By eliminating the process of removing harmful components, the processing apparatus can be configured inexpensively and compactly.

(E) Since the gas-liquid separation device and the gas-liquid contact device can be omitted, the processing device can be configured inexpensively and compactly.

According to a seventh aspect of the present invention, in the ozone water producing apparatus according to the sixth aspect, a gas containing oxygen is blown into the cathode chamber.

With this structure, in addition to the function of claim 6,
The following effects are obtained.

(A) Since the amount of hydrogen gas generated by electrolysis at the cathode can be reduced, there is no danger of explosion due to hydrogen gas.

(B) The ozone concentration in the anode chamber can be prevented from lowering due to the hydrogen gas pushed out from the cathode to the anode.

(C) Since an increase in resistance at the anode due to hydrogen gas flowing from the cathode can be prevented, a decrease in current efficiency can be prevented.

Next, the ozone generating electrode according to the embodiment of the present invention will be specifically described.

(Embodiment 1) FIG. 1 is a schematic structural view of an ozone generating electrode according to Embodiment 1.

In FIG. 1, reference numeral 1 denotes an anode which is the ozone generating electrode according to the first embodiment, 2 denotes an electrode substrate, 3 denotes an intermediate layer covering the electrode substrate 2, and 4 denotes an intermediate layer. An electrocatalyst containing a composite composition of a platinum group element.

The anode 1 serving as an ozone generating electrode was manufactured as follows.

First, a sintered body (porosity 60%) having a length and width of 50 mm × 120 mm and a plate thickness of 2 mm obtained by sintering a titanium fiber having a wire diameter of 0.1 mm was prepared as the electrode substrate 2.

One surface of the electrode substrate 2 is masked with a tape, and the other surface is electroplated with platinum under the plating conditions shown in Table 1 to form an intermediate layer 3 made of platinum with a film thickness of 3 μm. Then, a platinum base treatment was performed.

Then, the intermediate layer 3 was subjected to electroplating under the conditions of a plating solution having the composition shown in Table 2 and a current density of 1.5 A / dm ² at a temperature of 80 ° C. A platinum-chromium plating layer is formed, and the gas flow rate is 200 mL in an atmosphere of 30% oxygen and 70% nitrogen at 550 ° C.
/ Min. As a result, as shown in FIG. 1, the electrode substrate 2 formed of a porous body made of titanium
And an ozone generating electrode (anode 1) provided with an intermediate layer 3 made of platinum and an electrode catalyst 4 made of a composite composition containing chromium-platinum oxide.

[0076]

[Table 1]

[0077]

[Table 2]

The cation exchange membrane was prepared as follows.

As this cation exchange membrane, one obtained by heat treating Nafion 117 (registered trademark of DuPont, USA) at 120 ° C. as an ion exchange membrane was used.

The cathode was prepared as follows.

The reason why the gas diffusion electrode is used in the present invention is that the diffusion of the gas is generally low, so that the rate of diffusion of the gas is rate-determining and the overall reaction is prevented from being lowered. The reason for mixing the hydrophilic portion and the hydrophobic portion is that oxygen gas supplied to the cathode and water molecules flowing from the inside of the cathode to the outside of the electrode are mixed, so that the water molecules are quickly removed from the reaction system. .

Graphite powder having hydrophilic properties (manufactured by Denka Kogyo KK)
And a water suspension containing hydrophobic Teflon (registered trademark of DuPont, USA) were mixed, and 200 ° C. was applied to both sides of the carbon woven fabric.
And heat pressed.

A mixture of an aqueous suspension of carbon and Teflon having platinum supported on one side and Nafion (registered trademark of DuPont, USA) solution was heated and pressed at 120 ° C. to form a cathode.

The effective area of the above anode 1, cathode and ion exchange membrane was 60 cm ² .

(Embodiment 2) Instead of the titanium fiber sintered body of Embodiment 1, a platinum net obtained by knitting a wire having a platinum wire diameter of 0.1 mm into 200 mesh is used as an electrode substrate, and a platinum layer is used as a base. An ozone generating electrode (anode) having a configuration manufactured by the same steps as in Embodiment 1 except for the step of forming was obtained. The effective area of these anodes and the ion exchange membrane bonded to this anode was 60 cm ² .

(Embodiment 3) FIG. 2 is a schematic configuration diagram of an ozone water producing apparatus according to Embodiment 3.

In FIG. 2, reference numeral 10 denotes an ozone water producing apparatus according to Embodiment 3, 11 denotes an anode jacket for holding an anode portion, 12 denotes a cathode jacket for holding a cathode portion, and 13 denotes an intermediate portion between the anode jacket 11 and the cathode jacket 12. , A gas diffusion material having continuous pores constituting a cathode portion, 15 is an electrode catalyst of a cathode portion formed on the gas diffusion material 14 and placed in contact with the cation exchange membrane 13, Reference numeral 16 denotes an electrode substrate made of a porous body of the anode 1, and 17 denotes an electrode substrate formed on the electrode substrate 16.
3, an anode electrode catalyst disposed in contact with 3, 18 a current collecting terminal connected to the anode section and the cathode section, 19 an O-ring, 20
Is a joining member such as a bolt and a nut for joining the anode jacket 11 and the cathode jacket 12, 21 is a supply port for supplying water to the anode jacket 11, 22 is a gas and water discharge port,
Reference numeral 23 denotes an inlet for introducing a gas containing oxygen into the cathode jacket 12, and reference numeral 24 denotes a flow of a direct current between the electrode catalyst 15 and the electrode catalyst 17 to electrolyze water in the electrolytic cell including the anode jacket 11 and the cathode jacket 12. This is a voltage application unit for causing the voltage to be applied.

Here, the contact surfaces of the anode jacket 11 and the cathode jacket 12 with the current collector are formed in a trapezoidal shape by tightening the jacket with a coupling member 20 composed of nuts and bolts. The purpose of the present invention is to reduce the flow resistance of water flowing through the cathode chamber and the anode chamber during electrolysis and effect the rapid movement of gas.

The gas diffusion material 14 is formed using graphite that is hydrophilic, Teflon that is hydrophobic, and carbon woven fabric as materials, and has a characteristic that a hydrophilic portion and a hydrophobic portion coexist.

Electrode catalyst 1 coated on gas diffusion material 14
No. 5 is prepared by heating and compression bonding a supported carbon, a Teflon aqueous suspension and a Nafion solution mixture.

Next, an ozone water generation method applied to the ozone water production apparatus 10 of the present invention will be described with a specific example. As the ozone generation electrode, the electrode obtained in Embodiments 1 and 2 was used, and a comparative electrode having the following configuration was prepared as an electrode used in the comparative example.

The comparative electrodes were 50 mm × 120 mm each obtained by sintering titanium fiber having a wire diameter of 0.1 mm.
One side of a 2 mm-thick sintered body (porosity 60%) is masked with a tape, and the other surface is at 80 ° C. and 1.5 A
Platinum electroplating was carried out using a plating bath having the composition shown in Table 1 at a current density of / dm ^{2 to form} a 3 μm platinum plating film layer.

As the ion exchange membrane, Nafion 117 (registered trademark of DuPont, USA), which is a cation exchange membrane, was used for 120 times.
One that had been subjected to a heat treatment at ℃ was used. A graphite powder (manufactured by Denka Kogyo KK) and an aqueous suspension of Teflon (registered trademark of DuPont, U.S.A.) were mixed and heated and pressed at 200 ° C. on both surfaces of a carbon woven fabric. A mixture of platinum-supported carbon, a Teflon aqueous suspension, and Nafion (registered trademark of DuPont, USA) solution was further heated and pressed at 120 ° C. on one surface of the mixture to form a cathode. The effective area of these electrodes and the ion exchange membrane was 60 cm ² . This was used as the configuration of the comparative electrode.

(Example 1) The ozone generating electrode 1 of Embodiment 1 was used as an anode, and an ion exchange membrane and a cathode were closely attached to each other and incorporated in a titanium electrolytic cell. Activated carbon and water from which residual chlorine and solids had been removed by a hollow fiber membrane filter were supplied to the anode by a constant flow pump while maintaining the liquid temperature at 30 ° C. using a thermostat. Oxygen depressurized by a regulator was supplied from an oxygen cylinder to the cathode side. Current density is 1
Electrolysis was performed at 00 A / dm ² .

Example 2 An anode, an ion-exchange membrane, and a cathode using the platinum wire mesh of Embodiment 2 as an electrode substrate were closely attached to each other, and incorporated into a titanium electrolytic cell. Activated carbon and water from which chlorine and solids had been removed by a hollow fiber membrane filter were supplied to the anode by a constant flow pump while maintaining the liquid temperature at 30 ° C. using a thermostat. Oxygen depressurized by a regulator was supplied from an oxygen cylinder to the cathode side. Current density is 10
Electrolysis was performed at 0 A / dm ² .

Comparative Example An anode, an ion-exchange membrane and a cathode comprising the above-mentioned comparative electrode were respectively laminated and incorporated into a titanium electrolytic cell. Water was supplied to the anode by a pump, and oxygen was supplied to the cathode. Electrolysis was performed at a current density of 100 A / dm ² while maintaining the liquid temperature at 30 ° C. using a thermostat.

The above results are shown in (Table 3). As is clear from Table 3, in the electrolysis apparatus provided with the comparative electrode, the ozone concentration of the treated water from the water outlet on the anode side was 0.9 ppm, and the required power was 1185 wh / g of ozone. On the other hand, in the electrolysis according to the first and second embodiments, the ozone concentrations of the treated water from the water outlet on the anode side are 3.3 ppm and 3.5 ppm, respectively, and the required power is 24 ppm / g of ozone.
High concentration ozone water is obtained at 2wh and 228wh. When it is desired to obtain high-concentration ozone water, the supply of the water to be treated to the anode can be reduced or the electrolytic voltage can be increased.

[0098]

[Table 3]

The method for producing ozone water using the ozone generating electrode according to the present embodiment has the following functions because it has the above-described configuration.

(A) Since the cathode has a gas diffusion material, mass transfer of gas to the surface of the electrode catalyst is facilitated, a large current can flow, and high-concentration ozone can be generated quickly. Ozone can be produced with high efficiency.

(B) A porous electrode substrate is coated with an electrode catalyst composed of a platinum composite composition to form an anode, while an electrode composed of a gas diffusion material and an electrode catalyst is used as a cathode, and both electrodes are provided with an electrode. The surface thus formed is bonded to the cation exchange membrane and placed in the water to be treated, and a direct current is applied to the anode and the cathode to generate ozone by an electrochemical reaction, so that ozone can be produced with high efficiency.

(C) Since the respective electrode catalysts of the anode and the cathode are joined at a predetermined interval via the cation exchange membrane, the cations can be efficiently moved through the cation exchange membrane to increase the efficiency of ozone generation. be able to.

(D) Since the electrode catalyst is formed on the electrode substrate formed of the porous body, the concentration of ozone generated can be increased by increasing the contact area with the water to be treated.

(E) Since the electrode catalyst does not contain metals harmful to the environment such as lead dioxide, highly safe ozone water can be produced. In addition, by eliminating such harmful component removal processing, the processing apparatus can be configured inexpensively and compactly.

(F) Since high-concentration ozone water can be supplied, Escherichia coli and the like can be efficiently sterilized, and the safety of drinking water and food can be effectively improved.

(G) The pH of the generated ozone water is p
H does not significantly change, and a complicated gas-liquid contact device for suppressing a change in pH can be omitted.

[0107]

According to the ozone generating electrode of the first aspect, the following effects can be obtained.

(A) Since the electrode catalyst is formed on the electrode substrate formed of a porous body or a net-like body, the area of contact with the water to be treated can be increased to increase the concentration of ozone generated. At the same time, high-purity ozone is obtained.

(B) Since harmful metals such as lead dioxide do not elute in the environment, highly safe ozone water can be produced. In addition, such a harmful component removal process can be omitted, and the processing apparatus can be configured inexpensively and compactly.

(C) The power required for generating ozone is reduced, and ozone water can be produced at low processing cost.

(D) Since high-concentration ozone water can be supplied, Escherichia coli, which is a representative indicator bacterium, can be efficiently sterilized, and the safety of drinking water and food can be effectively improved.

(E) In the production of ozone water by the electrolytic method,
Since the pH of the generated ozone water does not significantly change with respect to the pH of the raw water and does not require a complicated gas-liquid contact device, it is possible to provide ozone generation which is clean and does not require complicated labor.

According to the invention described in claim 2, according to claim 1
In addition to the effects described above, the following effects can be obtained.

(A) Since the trivalent metal atom partially substituted with a platinum group atom activates the electrode, the hydroxyl group generated by the water splitting in the anodic oxidation is easily captured by the electrode. Can do well.

(B) Trivalent metal atom replacement operation can be adjusted by adjusting the ratio of metal in the plating solution of the electrode base material to give desired electrode characteristics, and the electrode can be made compact to save energy. It is possible to provide an excellent electrode for ozone generation.

According to the third aspect of the present invention, the first aspect is provided.
The following effects can be obtained in addition to the effects of the second or the second effects.

(A) Vanadium, chromium, cobalt,
The addition of iron, yttrium, lanthanum, and bismuth to the platinum group element makes it easier to react with the captured hydroxyl groups and oxygen, making it easier to generate ozone at a lower electrode potential, thereby enabling energy saving in ozone generation. It has the effect of.

(B) By changing the kind, content, composition ratio and the like of these elements, the electrode characteristics can be changed and an ozone generating electrode having a predetermined electrode potential can be obtained.
Therefore, it is possible to configure the ozone generation electrode at a low cost by selecting from these elements according to the use situation and the processing cost.

According to the ozone water producing method of the fourth aspect, the following effects can be obtained.

(A) Since the cathode has a gas diffusing substance, the gas generated on the surface of the electrode catalyst can be easily discharged to the outside through the communicating vent. Thereby, the catalyst surface is always activated and a large current can be flowed, and high concentration ozone can be generated quickly, and ozone can be produced with high efficiency.

(B) A part of the gas diffusion material can be formed by a hydrophilic part and the remaining part can be formed by a hydrophobic part. This facilitates mass transfer of a gaseous substance to the surface of the cathode electrode catalyst. The supply rate of the electrode reactant to the surface is increased, and high-concentration ozone can be generated quickly.

(C) Further, the electrode for water treatment is used as an anode, and the electrode composed of a gas diffusion material and an electrode catalyst is used as a cathode. Since ozone is generated by an electrochemical reaction by applying a direct current to the anode and the cathode, ozone can be produced with high efficiency.

(D) Since the respective anode and cathode electrode catalysts are joined at a predetermined interval via the cation exchange membrane, the cations can be moved through the cation exchange membrane without waste and the efficiency of ozone generation can be increased. be able to.

(E) Since the electrode catalyst is formed on the electrode substrate formed of a porous or reticulated body, the area of contact with the water to be treated can be increased to increase the concentration of ozone generated. .

(F) Since harmful metals such as lead dioxide do not elute in the environment, highly safe ozone water can be produced. In addition, by eliminating such harmful component removal processing, the processing apparatus can be configured inexpensively and compactly.

(G) Since high-concentration ozone water can be supplied, E. coli and the like can be efficiently sterilized, and the safety of drinking water and food can be effectively improved.

(H) The pH of the generated ozone water is p
There is no significant change in H and no complicated gas-liquid contact device is required, so no complicated labor is required.

According to the invention set forth in claim 5, according to claim 4,
In addition to the effects described above, the following effects can be obtained.

(A) Since the electrode catalyst is made of a platinum group element, ozone water can be efficiently produced at a low voltage.

(B) Since it does not contain metal components harmful to the environment, it is possible to produce ozone water that is highly safe as food or drinking water.

According to the ozone water producing apparatus of the sixth aspect, the following effects can be obtained.

(A) Since the anode and the cathode are joined via the cation exchange membrane, it is possible to realize an electrolytic device having a compact device configuration, a low voltage between electrodes, and excellent energy efficiency.

(B) Since the electrode catalyst is formed on the electrode substrate formed of a porous body or a network, the area of contact with the water to be treated can be increased to increase the concentration of ozone generated. .

(C) Since ozone-harmful metal components such as lead dioxide do not elute, highly safe ozone water can be produced. By eliminating the process of removing harmful components, the processing apparatus can be configured inexpensively and compactly.

According to the invention of claim 7, according to claim 6,
In addition to the effects described above, the following effects can be obtained.

(A) Since the amount of hydrogen gas generated by electrolysis at the cathode can be reduced, there is no danger of explosion due to hydrogen gas.

(B) It is possible to prevent a decrease in the ozone concentration in the anode chamber due to the hydrogen gas pushed out from the cathode to the anode.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an ozone generation electrode according to a first embodiment.

FIG. 2 is a schematic configuration diagram of an ozone water producing apparatus according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ozone generation electrode (anode) 2 Electrode substrate 3 Intermediate layer 4 Electrode catalyst 10 Ozone water production apparatus 11 Anode jacket 12 Cathode jacket 13 Cation exchange membrane 14 Gas diffusion material 15 Electrode catalyst 16 Electrode substrate 17 Electrode catalyst 18 Current collecting terminal DESCRIPTION OF SYMBOLS 19 O-ring 20 Joining member 21 Supply port 22 Discharge port 23 Inlet port 24 Voltage application part

Claims (7)

[Claims] 1. An electrode substrate comprising a porous body or a reticulated body and a composite composition comprising any one of an oxide of a platinum group element and an alloy containing a platinum group element. An electrode for generating ozone, comprising: an electrode catalyst to be coated. 2. The ozone generating electrode according to claim 1, wherein the composite composition has a composition in which a part of a platinum group atom is substituted with a trivalent metal atom. 3. The ozone generator according to claim 1, wherein the trivalent metal atom is at least one element selected from the group consisting of vanadium, chromium, cobalt, iron, yttrium, lanthanum, and bismuth. Electrodes. 4. An electrode provided with an electrode for ozone generation according to claim 1 and a cathode having an electrode catalyst formed on a gas diffusion material. A method for producing ozone water, comprising: arranging a cation exchange membrane in contact with the anode, and supplying electricity to the anode and the cathode to generate ozone by an electrochemical reaction of water supplied. 5. The method for producing ozone water according to claim 4, wherein the electrode catalyst of the cathode has a platinum group element. 6. An anode having the electrode for generating ozone according to any one of claims 1 to 3, a cathode having an electrode catalyst formed of a gas diffusion material having a communication hole, and the anode. A cation exchange membrane that abuts and binds to the respective electrode catalyst surfaces of the cathode, an anode jacket that holds an anode chamber in which the anode is arranged, a cathode jacket that holds a cathode chamber in which the cathode is arranged, and A supply unit for passing gas and treated water provided on a surface of the anode jacket and the cathode jacket that is in contact with the respective current collecting terminals, an electrolytic cell formed by fastening the anode jacket and the cathode jacket to each other, An ozone water producing apparatus, comprising: a voltage applying unit for flowing a direct current between the electrodes of the electrolytic cell. 7. The apparatus for producing ozone water according to claim 6, wherein a gas containing oxygen is blown into said cathode chamber.