JP2001300537A - Water purifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water purifier efficiently generating hydrogen peroxide from water such as city water, river water, underground water, rain water, and waste water, by electrolysis to efficiently decompose and remove impurities in water. SOLUTION: In this water purifier, water is fed into a cathode room 10 of an electrolytic bath 8 constituted by providing a membrane 7 between an anode room 9 and the cathode room 10, and dissolved oxygen in the water is electrolytically reduced in the cathode room 10 to produce hydrogen peroxide, and the impurities in the water are decomposed by the produced hydrogen peroxide or activated oxygen derived from the hydrogen peroxide. A cathode 5 formed of a single body or an alloy low in the efficiency of hydrogen generation at a time of electrolysis is arranged in the cathode room 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the generation of hydrogen peroxide by electrolyzing water such as tap water, river water, groundwater, rainwater, wastewater, etc., and the hydrogen peroxide and the active oxygen derived from the hydrogen peroxide. The present invention relates to a water purification device for purifying water by using the method.

[0002]

2. Description of the Related Art Conventionally, as a purification method for removing impurities, particularly organic substances, and the like contained in water such as tap water, a method using an adsorbent such as activated carbon or a filter material has been known. However, the performance of the adsorbent and the filter medium deteriorates as they are used, and there is a disadvantage that the adsorbent and the filter medium must be replaced at the end of life.

On the other hand, in order to make up for the drawbacks of the adsorbent, there has been proposed a method of performing oxidative or reductive decomposition by chemicals or electrolysis. For example, as a method of adding a drug, Japanese Patent Application Laid-Open No.
JP-A-50159 and JP-A-10-17421 disclose examples in which hydrogen peroxide is added. Further, as an example of oxidizing and reducing impurities by electrolysis, JP-A-11-180992 and JP-A-6-296968 disclose methods of generating active species by electrolysis and indirectly decomposing organic substances. I have.

In recent years, in particular, attempts have been made to generate hydrogen peroxide by electrolysis of water and to decompose impurities in water using the hydrogen peroxide as an active species. This makes it possible to decompose organic substances more easily and more reliably than adding hydrogen peroxide as a drug. An example of generating hydrogen peroxide by electrolysis of water is disclosed in
Japanese Patent Application Laid-Open No. 77056 discloses an organic matter oxidative decomposition method using a noble metal electrode, and Japanese Patent Application Laid-Open No. 11-104648 discloses an example of a seawater electrolysis apparatus using a gas diffusion electrode.

[0005]

However, when water is electrolyzed, hydrogen is mainly generated at the cathode and oxygen is generated at the anode. On the other hand, hydrogen peroxide is generated by reduction of dissolved oxygen at the cathode, but is generated as a competitive reaction with hydrogen generation by water electrolysis, and the hydrogen generation ability of the cathode becomes a problem. In addition, the dissolved oxygen concentration and the contact efficiency with the electrode are also problems.
Here, the concentration of dissolved oxygen in ordinary water is about 8 ppm, and hydrogen peroxide is generated by reducing this minute amount of dissolved oxygen at the cathode.

In the technique described in JP-A-11-77056, the cathode is formed of platinum, but platinum has a high ability to generate hydrogen and a low ability to generate hydrogen peroxide. Therefore, in this technique, ozone is generated at the anode by electrolysis, and the ozone water is electrolytically reduced to increase the hydrogen peroxide generating ability. However, lead dioxide must be used for the anode for ozone generation, and cannot be used for tap water or the like in consideration of toxicity and the like.

In the technique described in Japanese Patent Application Laid-Open No. Hei 6-336687, a porous carbon fiber material having good contact between a dissolved gas and an electrolyte and an electrode and having low electric resistance anisotropy is provided.
A carbon compact is used. However, carbon materials are not practical because of their low strength and wear.

[0008] The present invention has been made in view of the above-mentioned points, and hydrogen peroxide is generated from water such as tap water, river water, groundwater, rainwater, drainage, etc. by electrolysis with high efficiency to remove impurities in the water. It is an object of the present invention to obtain a water purification device that can be decomposed and removed with high efficiency.

[0009]

According to a first aspect of the present invention, there is provided a water purifying apparatus, wherein water is contained in a cathode chamber of an electrolytic cell formed by providing a diaphragm between an anode chamber and a cathode chamber. Supply,
Water for purifying water by electrolytically reducing dissolved oxygen in water in the cathode chamber 10 to generate hydrogen peroxide, and decomposing impurities in the water by the generated hydrogen peroxide or active oxygen derived from the hydrogen peroxide. The purifying apparatus is characterized in that a cathode 5 formed of a simple substance or an alloy having low hydrogen generation efficiency during electrolysis is disposed in a cathode chamber 10.

The invention according to a second aspect is characterized in that, in addition to the configuration of the first aspect, the cathode 5 is formed in a mesh structure.

The invention according to claim 3 is characterized in that, in addition to the structure of claim 1 or 2, a plurality of cathodes 5 are provided.

According to a fourth aspect of the present invention, in addition to any one of the first to third aspects, a water channel structure is formed by providing a partition plate 13 in the cathode chamber 10. It is.

According to a fifth aspect of the present invention, in addition to any one of the first to fourth aspects, a means for increasing the dissolved oxygen concentration of water supplied to the cathode chamber 10 is provided. It is a feature.

According to a sixth aspect of the present invention, in addition to the configuration of the fifth aspect, a means for increasing the dissolved oxygen concentration of water supplied into the cathode chamber 10 by mixing air into the cathode chamber 10. It is characterized by comprising.

According to a seventh aspect of the present invention, in addition to the constitution of the fifth aspect, dissolved oxygen of water supplied to the cathode chamber 10 is obtained by bubbling air into water before being supplied to the cathode chamber 10. It is characterized by comprising means for increasing the concentration.

According to an eighth aspect of the present invention, in addition to the structure of the fifth aspect, the cathode 5 having a mesh structure is formed by weaving a hollow wire 14 having pores 15 so that the wire 14 can be used during electrolysis. Air is supplied to the hollow portion 30 of the
The means for increasing the dissolved oxygen concentration of the water supplied to the cathode chamber 10 is formed by a configuration in which air is fed into the cathode chamber 10 from above.

According to a ninth aspect of the present invention, in addition to the configuration of the fifth aspect, water is supplied to the cathode chamber 10 by anodic electrolysis of water before being supplied to the cathode chamber 10 to generate oxygen. It is characterized by comprising means for increasing the dissolved oxygen concentration of water.

The invention according to claim 10 is the first invention.
In addition to any one of the above configurations, a mechanism for generating active oxygen from hydrogen peroxide in water is arranged in a flow path of water downstream of the cathode chamber 10.

The invention according to claim 11 is the first invention.
In addition to the above configuration, a mechanism for generating active oxygen from hydrogen peroxide in water is provided by providing a mesh metal in a flow path of water on the downstream side of the cathode chamber 10. is there.

The invention according to claim 12 is the first invention.
In addition to the configuration of FIG. 2, a mechanism for generating active oxygen from hydrogen peroxide in water is provided by providing an ultraviolet irradiation unit 29 for irradiating ultraviolet light to water flowing downstream of the cathode chamber 10. It is assumed that.

[0021]

Embodiments of the present invention will be described below.

In the water purification apparatus of the present invention, there is provided an electrolytic cell 8 for supplying water such as tap water, river water, groundwater, rainwater, drainage, etc., and electrolyzing this water. Hydrogen peroxide is generated by an electrolytic reaction in the chamber 10, and water is purified by the hydrogen peroxide and active oxygen derived from the hydrogen peroxide. By using a material having a low hydrogen generation efficiency at the time of electrolysis as a cathode material constituting the cathode 5, the electrolysis efficiency is advantageous for generating hydrogen peroxide. Further, by forming the shapes of the cathode 5 and the electrolytic cell 8 such that the water flow passes through the cathode 5, the dissolved oxygen component in the water is brought into contact with the cathode 5 efficiently, and the generation efficiency of hydrogen peroxide is increased. You can also.

The electrolytic reaction at each electrode is shown below. In the cathodic reaction, hydrogen is generated by electrolysis of water as shown in equation (1), and oxygen is reduced as shown in equations (2) to (4) to generate hydrogen peroxide. The present invention is intended to minimize the reaction of the formula (1) and promote the reaction of the formula (2) to the maximum.

[0024] (cathodic ^{reaction) 2H + + 2e - → H} 2 (1) O 2 + e - → O 2 - · (2) O 2 - · + H + → HOO · (3) 2HOO · → H 2 O ₂ + O ₂ (4) (anode _{reaction) H 2 O → 1 / 2O} 2 + 2H + + 2e - (5) 10, and the case in which the cathode 5 made of Pt as the cathode 5 to the electrolytic tank 8, In the case where the cathode 5 made of SUS (stainless steel) is provided, water is electrolyzed in the electrolytic cell 8 in a flowing water system, and the result of measuring the difference in the amount of generated hydrogen peroxide due to the difference in the cathode 5 is shown. The used water is obtained by dissolving NaSO ₄ in pure water and having conductivity equivalent to tap water. The cathode 5 used had a mesh structure. In the figure, ● represents the hydrogen peroxide concentration with respect to the electrolysis voltage in the produced water in the cathode chamber 10 when the cathode 5 is formed of SUS, and ▼ represents the concentration of the produced water in the cathode chamber 10 when the cathode 5 is formed of Pt. The hydrogen peroxide concentration with respect to the electrolysis voltage, and は indicates the current value with respect to the electrolysis voltage when the cathode 5 was formed of SUS,
▽ indicates a current value with respect to an electrolytic voltage when the cathode 5 is formed of Pt.

In this case, the voltage-current characteristics show the same characteristics in both cases, but a large difference was observed in the amount of hydrogen peroxide generated depending on the cathode material. In this case, if an electrode made of SUS is used as the cathode 5, the efficiency of generating hydrogen peroxide is high and the efficiency of generating hydrogen is low, so that the efficiency of generating hydrogen peroxide can be increased, and the efficiency of purifying water can be increased. Hereinafter, specific embodiments will be described.

(Embodiment 1) In this embodiment, hydrogen peroxide is generated from dissolved oxygen in water by electrolysis on the cathode 5 side in an electrolytic tank 8 provided with a diaphragm 7 between the anode 6 and the cathode 5. And a water purification apparatus for purifying water by decomposing impurities in water with active oxygen derived from the hydrogen peroxide, and using a simple substance or an alloy having low hydrogen generation efficiency during electrolysis as an electrode material for forming the cathode 5 Preferably, among such electrode materials, those having a high efficiency of generating hydrogen peroxide during electrolysis are preferably used.

Thus, the efficiency of hydrogen generation during electrolysis is low,
As an electrode material having a high hydrogen peroxide generation efficiency, in particular, Fe
And SUS (stainless steel), which is an alloy containing Fe as a main component, and ferrite. Hg, Pb,
Like Sn, Cd, Cu, Ni, Ag, Co, Au,
Metals with low hydrogen generation efficiency during electrolysis and alloys composed of these metals can also be used. On the other hand, Pt or Pd simple substance or alloy has high hydrogen generation efficiency and is excluded from the electrode material for forming the cathode 5.

FIG. 1 shows a specific embodiment of the present invention.
An electrolytic cell 8 is provided in the middle of a pipe in a flow path of water such as tap water, river water, groundwater, rainwater, and drainage. The interior of the electrolytic cell 8 is partitioned by a diaphragm 7 into an anode chamber 9 and a cathode chamber 10.
The anode 6 is disposed in the anode chamber 9, and the cathode 5 is disposed in the cathode chamber 10. Pipelines 1 and 2 are connected to the cathode chamber 10 and the anode chamber 9 on the upstream side, respectively.
, Water such as tap water is supplied to the cathode chamber 10 and the anode chamber 9. Further, pipe lines 3 and 4 are connected to the cathode chamber 10 and the anode chamber 9, respectively, on the downstream side.

In purifying water, water is supplied to the pipelines 1 and 2 by a pump or the like. On the anode chamber 9 side, water flows into the anode chamber 9 through the pipe 2, is oxidized by the anode 6, generates oxygen from water molecules, and is discharged through the pipe 4.
On the other hand, the water to be purified on the cathode chamber 10 side flows into the cathode chamber 10 through the pipe 1, is reduced by the cathode 5, and is discharged out of the electrolytic cell 8 through the pipe 3. At this time, hydrogen is generated from water molecules on the surface of the cathode 5, and at the same time, dissolved oxygen is reduced on the cathode 5 to generate hydrogen peroxide. By the action of the hydrogen peroxide, impurities in the water are decomposed and removed.

In the present embodiment, the cathode 5 is formed of a metal material such as SUS (stainless steel), which has a low ability to generate hydrogen during electrolysis and a high ability to generate hydrogen peroxide. It is capable of generating hydrogen peroxide with high efficiency and improving the efficiency of decomposing impurities in water. The anode material is not particularly limited, but Pt, which is an insoluble electrode, may be used.
A single electrode, an electrode plated with Pt, or the like can be used.

(Embodiment 2) In the present embodiment, the shape of the cathode 5 is formed in a mesh structure (mesh shape), and water flowing into the cathode chamber 10 passes through the mesh structure of the cathode 5 so that Thus, the chance of contact between the cathode 5 and the cathode 5 is increased.

FIG. 2 shows an electrolytic cell 8 of the water purification apparatus according to the present embodiment.
The following shows a specific example. The inside of the electrolytic cell 8 is provided with an anode chamber 9 by a diaphragm 7.
And a cathode chamber 10. Similar to the first embodiment, the cathode chamber 10 and the anode chamber 9 are connected to the pipelines 1 and 2 on the upstream side, respectively, and are connected to the pipelines 3 and 4 on the downstream side, respectively. Is connected. Here, the inside of the cathode compartment 10 is partitioned by the cathode 5 into an upstream compartment 10a and a downstream compartment 10b, and the upstream compartment 10a is located on the diaphragm 7 side and the downstream compartment 10b is provided.
Are arranged on the opposite side of the diaphragm 7 respectively. The upstream pipeline 1 is connected to the upstream branch 10a, and the downstream pipeline 3 is connected to the downstream branch 10b.

In purifying water, water is supplied to the pipelines 1 and 2 by a pump or the like. On the anode chamber 9 side, water flows into the anode chamber 9 through the pipe 2, is oxidized by the anode 6, generates oxygen from water molecules, and is discharged through the pipe 4.
On the other hand, water to be purified on the cathode chamber 10 side flows into the cathode chamber 10 through the pipe 1. Here, the water that has entered the cathode compartment 10 is first supplied to the upstream compartment 10a,
After flowing through the mesh-shaped cathode 5 having a mesh structure and flowing into the downstream side compartment 10b, it is discharged through the conduit 3 to the outside of the electrolytic cell 8. At this time, hydrogen is generated from water molecules on the surface of the cathode 5 and at the same time, dissolved oxygen is reduced on the cathode 5 to generate hydrogen peroxide. Here, since the water supplied to the cathode chamber 10 always comes into contact with the cathode 5, the efficiency of the electrolytic reaction on the surface of the cathode 5 is improved, and hydrogen peroxide is generated with higher efficiency. Will be further improved. Hydrogen and hydrogen peroxide generated on the cathode 5 pass through the mesh of the cathode 5 and are led out of the electrolytic cell 8 through the pipe 3.

In the case of this embodiment, for example, a SUS316 electrode of # 200 can be used as the cathode 5.

(Embodiment 3) In this embodiment, the cathode chamber 10
By providing a plurality of cathodes 5 therein, the probability of contact between water and cathode 5 is increased, and the efficiency of generating hydrogen peroxide due to reduction of dissolved oxygen in water by contact with cathode 5 is increased. Things.

FIG. 3 shows an electrolytic cell 8 of the water purification apparatus according to the present embodiment.
Here is an example. The inside of the electrolytic cell 8 is partitioned by a diaphragm 7 into an anode chamber 9 and a cathode chamber 10. Similar to the first embodiment, conduits 1 and 2 are connected to the cathode chamber 10 and the anode chamber 9 on the upstream side, respectively. On the downstream side, pipelines 3 and 4 are connected, respectively. Here, in the cathode compartment 10, the cathode 5 formed in a mesh structure that partitions the upstream compartment 10a disposed on the diaphragm 7 side and the downstream compartment 10b disposed on the opposite side of the diaphragm 7 from each other.
Are arranged. In the illustrated example, three cathodes 5a, 5b, 5c are provided as the cathode 5,
The number of cathodes 5 is not particularly limited. In the cathode chamber 10, the upstream pipeline 1 is connected to the upstream branch 10a,
The downstream pipeline 3 is connected to the downstream branch 10b.

In purifying water, water is supplied to the pipelines 1 and 2 by a pump or the like. On the anode chamber 9 side, water flows into the anode chamber 9 through the pipe 2, is oxidized by the anode 6, generates oxygen from water molecules, and is discharged through the pipe 4.
On the other hand, water to be purified on the cathode chamber 10 side flows into the cathode chamber 10 through the pipe 1. Here, the water that has entered the cathode compartment 10 is first supplied to the upstream compartment 10a,
A plurality of cathodes 5 having a mesh structure
After passing through a, 5b and 5c and flowing into the downstream branch 10b, it is discharged out of the electrolytic cell 8 through the conduit 3. At this time, hydrogen is generated from water molecules on the surface of the cathode 5 and at the same time, dissolved oxygen is reduced on the cathode 5 to generate hydrogen peroxide. Here, since the water supplied to the cathode chamber 10 always comes into contact with the plurality of cathodes 5a, 5b, 5c, the water comes in contact with the cathode 5 three times as frequently as in the case of one cathode 5 in this case.
Therefore, it is considered that the amount of generated hydrogen peroxide is also tripled, and hydrogen peroxide is generated with higher efficiency, and the efficiency of decomposing impurities in water is further improved. Cathode 5
The hydrogen and hydrogen peroxide generated above pass through the mesh of the cathode 5 and are led out of the electrolytic cell 8 through the pipe 3.

(Embodiment 4) In this embodiment, the cathode chamber 10
The frequency of contact between water and the cathode 5 is improved by forming and adjusting a water channel structure by providing a partition plate 13 at the bottom.

FIG. 4 shows an electrolytic cell 8 of the water purification apparatus of the present embodiment.
The following shows a specific example. The inside of the electrolytic cell 8 is provided with an anode chamber 9 by a diaphragm 7.
And a cathode chamber 10. Similar to the first embodiment, the cathode chamber 10 and the anode chamber 9 are connected to the pipelines 1 and 2 on the upstream side, respectively, and are connected to the pipelines 3 and 4 on the downstream side, respectively. Is connected. Here, the inside of the cathode chamber 10 is partitioned by a cathode 5 formed in a mesh structure into a compartment 11 arranged on the diaphragm 7 side and a compartment 12 arranged on the opposite side to the diaphragm 7. Furthermore, the inside of each of the compartments 11 and 12 is divided into one or a plurality of locations by a partition plate 13 between the upstream side and the downstream side,
Each is divided into multiple sub-chambers. In the illustrated example, two partition plates 13a, 13c are disposed in one compartment 11 and partitioned into three small compartments 11a, 11b, 11c, and one partition plate 13 is provided in the other compartment 12.
b is arranged and divided into two small compartments 12a and 12b. In each of the compartments 11 and 12, partition plates 13 are disposed so as to be alternately arranged.
1b, 11c, 12a and 12b are composed of small compartments 11a, 11b and 11c arranged in one compartment 11 and small compartments 12a and 12b arranged in the other compartment 12.
They are arranged alternately from the upstream side to the downstream side so as to be adjacent to each other via the mesh cathode 5. In the cathode chamber 10, the upstream pipe line 1 is connected to the sub-compartment 11a arranged on the most upstream side among the sub-compartments, and the downstream side is connected to the sub-compartment 11c arranged on the most downstream side. Are connected.

In purifying water, water is supplied to the pipelines 1 and 2 by a pump or the like. On the anode chamber 9 side, water flows into the anode chamber 9 through the pipe 2, is oxidized by the anode 6, generates oxygen from water molecules, and is discharged through the pipe 4.
On the other hand, the water to be purified on the side of the cathode compartment 10 is supplied to the cathode compartment 10 through the pipe 1, and firstly the small compartment 11 of the compartment 11
flows into a. Here, the flow of the water flow is changed to the partition plate 13a, passes through the cathode 5 in a mesh shape, and flows into the small sub-chamber 12a of the sub-chamber 12. Here, the water flow is again applied to the partition plate 13.
b, the path is changed to pass through the mesh-shaped cathode 5,
It flows into the small compartment 11b of the compartment 11. Further, the partition plate 13
The path is changed to c and passes through the mesh-shaped cathode 5 and flows into the small compartment 12b of the compartment 12. After passing through the mesh-shaped cathode 5 again and flowing into the small compartment 11c of the compartment 11, it is discharged out of the electrolytic cell 8 through the conduit 3.

In the present embodiment, the water supplied to the cathode chamber 10 always comes into contact with the cathode 5 and passes through the cathode 5 a plurality of times (a total of four times in the illustrated example). Is also expected to be quadrupled, and the efficiency of hydrogen peroxide generation can be increased. Therefore, the decomposition efficiency of impurities in water can be further improved.

In the illustrated embodiment, the number of passages of the cathode 5 in the cathode chamber 10 is four, but the number of passages of the cathode 5 is not limited to this.

(Embodiment 5) In this embodiment, the concentration of dissolved oxygen in water before electrolysis is increased by bubbling air into the water before electrolysis in the electrolysis tank 8 to generate hydrogen peroxide during electrolysis. It increases efficiency.

FIG. 5 shows an electrolytic cell 8 of the water purification apparatus of the present embodiment.
Here is an example. The electrolytic cell 8 is formed in the same manner as in the second embodiment. A bubbling section 16 is provided in the middle of the pipe 1 connected to the upstream side of the cathode chamber 10. One end of an air supply pipe 17 is inserted into the bubbling section 16,
An air outlet 32 is provided at one end of the air supply pipe 17 arranged in the bubbling section 16. A pump 18 is provided on the other end side of the air supply pipe 17. When the pump 18 is operated, air is supplied from the air discharge port 32 into the bubbling unit 16 through the air supply pipe 17.

In performing electrolysis of water in the electrolytic cell 8, water is circulated through the pipe 1 and supplied to the cathode chamber 10 of the electrolytic cell 8, and the pump 18 is operated to supply air to the bubbling section 16. When air is supplied, air is taken into the water flowing through the pipe line 1 by bubbling in the bubbling unit 16, whereby the dissolved oxygen concentration in the water increases. The bubbling water is supplied to the cathode chamber 10 and the dissolved oxygen is reduced on the surface of the cathode 5 to generate hydrogen peroxide as in the case of Embodiment 2, but the dissolved oxygen concentration in the water is increased. Therefore, hydrogen peroxide is generated with higher efficiency, and the efficiency of decomposing impurities in water is further improved. Hydrogen and hydrogen peroxide generated on the cathode 5 pass through the mesh of the cathode 5, pass through the pipe 3, and pass through the electrolytic cell 8.
Led out.

In the present embodiment, the bubbling method using the pump 18 has been described as a method for bubbling water, but the bubbling method is not limited to this method.

(Embodiment 6) In this embodiment, the cathode 5 in each of the above embodiments is formed by weaving a tubular wire 14 having a large number of pores 15 on its surface to form a mesh structure (mesh shape). The end of the wire 14 is connected to a pump or the like to connect the wire 14 during electrolysis.
Air is supplied to the hollow part 30 inside the
By sending the water from 5 to the water, air can be supplied to the water in the cathode chamber 10 to increase the dissolved oxygen concentration and increase the efficiency of generating hydrogen peroxide.

FIG. 6A shows an example of the cathode 5 of this embodiment. The cathode 5 has pores 15 on its surface as shown in FIG.
And a wire rod 14 formed by applying metal plating so as to have conductivity on the surface of a hollow fiber tube having a hollow portion 30 communicating with the pores 15 therein, and woven in a mesh shape. It is formed by this.

In the electrolysis, the end of the wire 14 is connected to a pump or the like, and the pump is operated at the time of electrolysis, so that air is supplied into the wire 14 and the air is sent from the fine holes 15 to the water. At this time, at the same time as the water passes through the mesh of the cathode 5, air is sent into the water from the fine holes 15 on the surface of the wire 14, and the air is bubbled into the water passing through the cathode 5, and the water is dissolved. Oxygen concentration improves. Therefore, hydrogen peroxide is generated with higher efficiency by the electrolytic reaction on the cathode 5, and the efficiency of decomposing impurities in water is further improved.

In this embodiment, the wire 14 is formed by using a hollow fiber tube and plating the surface of the hollow fiber tube with a conductive substance by metal plating. The method is not limited.

(Embodiment 7) In the present embodiment, an oxygen-adding electrolytic cell 31 is provided as another electrolytic cell on the upstream side of the hydrogen peroxide-generating electrolytic cell 8 described above. 3
A process in which water before being supplied to the cathode chamber 10 of the electrolytic cell 8 is subjected to anodic electrolysis (electrolytic oxidation) to generate oxygen, and this oxygen is mixed with the water supplied to the cathode chamber 10 of the electrolytic cell 8 in 1 In addition, the concentration of dissolved oxygen in water is improved to further improve the generation efficiency of hydrogen peroxide.

FIG. 7 shows an example of the water purification apparatus of the present embodiment. As the electrolytic cell 8, the same as that shown in the second embodiment is provided. In addition, the electrolytic cell 31 for oxygen addition
The inside is partitioned by a diaphragm 20 into a cathode chamber 26 and an anode chamber 27. The cathode chamber 26 is provided with a cathode 19, and the anode chamber 27 is provided with an anode 21. The downstream end of the anode chamber 27 is connected to the upstream end of the pipeline 1 connected to the cathode chamber 10 of the electrolytic cell 8, and the pipeline 24 is connected to the upstream side. Further, pipe lines 23 and 22 are connected to the upstream side and the downstream side of the cathode chamber 26, respectively.

In purifying the water, the water is supplied through line 2
3, 24, 2. Water is supplied to the cathode chamber 26 side of the electrolytic cell 31 for oxygen addition through the pipe 23,
At 9, the water molecules are reduced to produce hydrogen, which is discharged through line 22. On the other hand, the water to be purified is supplied to the anode chamber 27 of the electrolytic cell 31 for oxygen addition through the pipe 24.
Here, water molecules are oxidized at the anode 21 to generate oxygen, and this oxygen is mixed into the water to increase the dissolved oxygen concentration. The water is discharged to the outside of the oxygenation electrolytic cell 31 through the pipe 1 in this state. This water passes through the pipe 1 and the cathode chamber 10 of the electrolytic cell 8.
Flows into the upstream branch 10a. Here, the water that has entered the cathode chamber 10 passes through the mesh-shaped cathode 5 and passes through the downstream compartment 10.
b, and at this time, hydrogen is generated on the surface of the cathode 5 and dissolved oxygen in water is reduced on the surface of the cathode 5 to generate hydrogen peroxide. The generated hydrogen and hydrogen peroxide flow into the water flow, flow into the downstream branch 10b, and are discharged out of the electrolytic cell 8 through the pipe 3. After the dissolved oxygen concentration is improved in the anode chamber 27 of the oxygenation electrolytic cell 31 as described above,
By performing cathodic electrolysis of dissolved oxygen in the electrolytic cell 8, the cathodic electrolysis of this dissolved oxygen easily occurs, so that the efficiency of generating hydrogen peroxide is further increased, and the efficiency of decomposing impurities in water is further improved. Become.

In this embodiment, an oxygen-adding electrolytic cell 31 which is a separate electrolytic cell is provided upstream of the electrolytic cell 8 for generating hydrogen peroxide.
Is provided as an example of an electrolytic cell for oxygen generation, but the configuration of the electrolytic cell for oxygen generation is not limited to such a configuration. For example, the downstream side of the pipe 4 of the electrolytic tank 8 is connected to the upstream side of the pipe 1 without separately providing the electrolytic cell 31 for oxygen addition, and supplied to the anode chamber 9 of the electrolytic tank 8 for the electrolytic reaction. The water having an increased dissolved oxygen concentration may be further supplied to the cathode chamber 10 of the electrolytic cell 8 to generate and mix hydrogen peroxide.

(Embodiment 8) In this embodiment, in order to generate active oxygen from hydrogen peroxide generated in water, a mesh metal such as SUS (stainless steel) is provided downstream of the electrolytic cell 8. It is provided with a metal filter, and purifies water with hydrogen peroxide and active oxygen.

FIG. 8 shows an example of the water purification apparatus of this embodiment. As the electrolytic cell 8, the same as in the second embodiment is provided. An iron mesh filter 28 is provided as a mesh metal in the middle of the pipe downstream of the pipe 3 connected to the cathode chamber 10 of the electrolytic cell 8 on the downstream side.

In purifying water, water is supplied to the pipelines 1 and 2 by a pump or the like. On the anode chamber 9 side, water flows into the anode chamber 9 through the pipe 2, is oxidized by the anode 6, generates oxygen from water molecules, and is discharged through the pipe 4.
On the other hand, water to be purified on the cathode chamber 10 side flows into the cathode chamber 10 through the pipe 1. Here, the water that has entered the cathode compartment 10 is first supplied to the upstream compartment 10a,
After flowing through the mesh-shaped cathode 5 having a mesh structure and flowing into the downstream side compartment 10b, it is discharged through the conduit 3 to the outside of the electrolytic cell 8. At this time, hydrogen is generated from water molecules on the surface of the cathode 5 and at the same time, dissolved oxygen is reduced on the cathode 5 to generate hydrogen peroxide. Here, since the water supplied to the cathode chamber 10 always comes into contact with the cathode 5, the efficiency of the electrolytic reaction on the surface of the cathode 5 is improved, and hydrogen peroxide is generated with higher efficiency.

The water containing hydrogen peroxide supplied from the cathode chamber 10 to the pipe 3 passes through the iron mesh filter 28, and at this time reacts to generate active oxygen. That, Fenton reaction ^{_{H 2 O 2 + Fe 2+ →}} Fe 3+ + OH - + O
H. is generated on the iron mesh filter 28 to generate active oxygen from hydrogen peroxide. Since active oxygen has stronger oxidizing power than hydrogen peroxide, it can further promote water purification.

In this embodiment, an iron mesh filter 28 made of SUS or the like is shown as the mesh metal. However, the material and shape of the mesh metal are not particularly limited, and radicals are generated by decomposing hydrogen peroxide. What is necessary is just to make it.

(Embodiment 9) In this embodiment, an ultraviolet irradiation section 29 is provided in the flow path of water downstream of the electrolytic cell 8 in order to generate active oxygen from hydrogen peroxide generated in water. It purifies water with hydrogen and active oxygen.

FIG. 9 shows an example of the water purification apparatus of this embodiment. As the electrolytic cell 8, the same one as in the second embodiment is provided. In the middle of the pipe downstream of the conduit 3 connected to the cathode chamber 10 downstream of the electrolytic cell 8, an ultraviolet irradiation unit 2 is provided.
9 are provided. An ultraviolet lamp is provided in the ultraviolet irradiation unit, and the ultraviolet lamp can irradiate water flowing through the conduit 3 with the ultraviolet lamp.

In purifying water, water is supplied to the pipelines 1 and 2 by a pump or the like. On the anode chamber 9 side, water flows into the anode chamber 9 through the pipe 2, is oxidized by the anode 6, generates oxygen from water molecules, and is discharged through the pipe 4.
On the other hand, water to be purified on the cathode chamber 10 side flows into the cathode chamber 10 through the pipe 1. Here, the water that has entered the cathode compartment 10 is first supplied to the upstream compartment 10a,
After flowing through the mesh-shaped cathode 5 having a mesh structure and flowing into the downstream side compartment 10b, it is discharged through the conduit 3 to the outside of the electrolytic cell 8. At this time, hydrogen is generated from water molecules on the surface of the cathode 5 and at the same time, dissolved oxygen is reduced on the cathode 5 to generate hydrogen peroxide. Here, since the water supplied to the cathode chamber 10 always comes into contact with the cathode 5, the efficiency of the electrolytic reaction on the surface of the cathode 5 is improved, and hydrogen peroxide is generated with higher efficiency.

The water containing hydrogen peroxide supplied from the cathode chamber 10 to the pipe line 3 passes through the ultraviolet irradiation section 29, and at this time, is subjected to a photoexcitation reaction by irradiation of ultraviolet rays,
Active oxygen is generated. In other words, active oxygen is generated from hydrogen peroxide by the photochemical reaction H ₂ O ₂ + hv → 2OH. Since active oxygen has stronger oxidizing power than hydrogen peroxide, it can further promote water purification.

[0064]

As described above, the water purifying apparatus according to the first aspect of the present invention supplies water into the cathode chamber of an electrolytic cell having a diaphragm provided between the anode chamber and the cathode chamber, This is a water purification apparatus that purifies water by electrolytically reducing dissolved oxygen in water to generate hydrogen peroxide, and decomposing impurities in the water by the generated hydrogen peroxide or active oxygen derived from the hydrogen peroxide. Therefore, since a cathode formed of a simple substance or an alloy having low hydrogen generation efficiency during electrolysis is disposed in the cathode chamber, hydrogen peroxide can be generated with high efficiency from water to be purified, and hydrogen peroxide can be generated. Water can be efficiently purified.

According to a second aspect of the present invention, in addition to the structure of the first aspect, the shape of the cathode is formed in a mesh structure.
The water to be purified can be brought into contact with the cathode in the cathode chamber with a high probability, and hydrogen peroxide can be generated with higher efficiency.

According to a third aspect of the present invention, in addition to the constitution of the first or second aspect, a plurality of cathodes are provided, so that the water to be purified is brought into contact with the cathodes in the cathode chamber with a higher probability. Thus, hydrogen peroxide can be generated with higher efficiency.

According to a fourth aspect of the present invention, in addition to the configuration of any one of the first to third aspects, since a water channel structure is formed by providing a partition plate in the cathode chamber, the water channel structure is adjusted for purification. By increasing the number of times the target water contacts the cathode, water can be brought into contact with the cathode a plurality of times, and hydrogen peroxide can be generated with higher efficiency.

According to a fifth aspect of the present invention, in addition to any one of the first to fourth aspects, a means for increasing the concentration of dissolved oxygen in water supplied to the cathode chamber is provided. By increasing the amount of dissolved oxygen to be provided, the number of contacts between the cathode and dissolved oxygen can be increased, and hydrogen peroxide can be generated with higher efficiency.

According to a sixth aspect of the present invention, in addition to the structure of the fifth aspect, there is provided means for increasing the dissolved oxygen concentration of water supplied into the cathode chamber by mixing air into the cathode chamber. By mixing air, the amount of dissolved oxygen supplied to the electrolytic reaction can be increased to increase the number of contacts between the cathode and the dissolved oxygen, and hydrogen peroxide can be generated with higher efficiency. It is.

According to a seventh aspect of the present invention, in addition to the configuration of the fifth aspect, the dissolved oxygen concentration of the water supplied to the cathode chamber is reduced by bubbling air before the water is supplied to the cathode chamber. By providing a means for increasing the amount of dissolved oxygen supplied to the electrolytic reaction by mixing air by bubbling, the number of contacts between the cathode and the dissolved oxygen can be increased, and hydrogen peroxide can be further reduced. It can be generated with high efficiency.

According to the eighth aspect of the present invention, in addition to the constitution of the fifth aspect, a cathode having a mesh structure is formed by weaving a hollow wire having pores, and the cathode is formed in a hollow portion of the wire during electrolysis. By forming a means to increase the dissolved oxygen concentration of water supplied to the cathode chamber by supplying air and feeding air into the cathode chamber from the pores, electrolysis is performed by mixing air by bubbling. By increasing the amount of dissolved oxygen provided for the reaction, the number of contacts between the cathode and the dissolved oxygen can be increased, and the cathode itself is made the same as a mechanism for bubbling air into water, thereby increasing oxygen by bubbling. Electrolysis can be made efficient,
Hydrogen peroxide can be generated with higher efficiency.

According to a ninth aspect of the present invention, in addition to the configuration of the fifth aspect, water supplied to the cathode chamber is generated by anodic electrolysis of water before being supplied to the cathode chamber to generate oxygen. Since a means for increasing the dissolved oxygen concentration is provided, oxygen can be generated from the electrolysis of water itself to increase the dissolved oxygen concentration, and the number of contacts between the cathode and the dissolved oxygen can be increased. It can be generated with high efficiency.

The tenth aspect of the present invention is the first aspect of the present invention.
In addition to the configuration of any one of (1) to (9), a mechanism for generating active oxygen from hydrogen peroxide in the water is provided in the flow path of water on the downstream side of the cathode chamber. It is possible to purify water in combination with active oxygen having a high water content, and to further improve the water purification efficiency.

The invention described in claim 11 is the first invention.
In addition to the configuration of No. 0, a mechanism for generating active oxygen from hydrogen peroxide in water by providing a mesh-like metal in the water flow path on the downstream side of the cathode chamber has been constructed. Oxygen is generated, and water can be purified using hydrogen peroxide in combination with active oxygen having an oxidizing power stronger than hydrogen peroxide, so that the water purification efficiency can be further improved.

The twelfth aspect of the present invention is the first aspect of the present invention.
In addition to the above configuration, a mechanism is provided to generate active oxygen from hydrogen peroxide in water by providing an ultraviolet irradiation unit that irradiates ultraviolet light to water flowing downstream of the cathode chamber. Active oxygen is generated from hydrogen, and water can be purified using hydrogen peroxide and active oxygen having a stronger oxidizing power than hydrogen peroxide, and the water purification efficiency can be further improved. It is.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a second embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating a configuration of a third embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a configuration of a fourth embodiment of the present invention.

FIG. 5 is a schematic diagram showing a configuration of a fifth embodiment of the present invention.

FIG. 6 shows a configuration of a sixth embodiment of the present invention.
(A) is a front view showing a cathode, (b) is an enlarged view of a portion (a), and (c) is a cutaway perspective view showing a part of (a).

FIG. 7 is a schematic diagram showing a configuration of Embodiment 7 of the present invention.

FIG. 8 is a schematic diagram showing a configuration of Embodiment 8 of the present invention.

FIG. 9 is a schematic diagram showing a configuration of a ninth embodiment of the present invention.

FIG. 10 is a graph showing changes in the amount of hydrogen peroxide generated and the current value with respect to the electrolytic voltage depending on the difference in cathode.

[Description of Signs] 5 Cathode 7 Diaphragm 8 Electrolyzer 9 Anode chamber 10 Cathode chamber 13 Partition plate 14 Wire rod 15 Pores 29 Ultraviolet irradiation part 30 Hollow part

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[Procedure amendment]

[Submission date] July 24, 2000 (2007.2
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction contents]

[0024] (cathodic ^{reaction) 2H + + 2e - → H} 2 (1) O 2 + e - → O 2 - · (2) O 2 - · + H + → HOO · (3) 2HOO · → H 2 O ₂ + O ₂ (4) (anode _{reaction) H 2 O → 1 / 2O} 2 + 2H + + 2e - (5) 10, and the case in which the cathode 5 made of Pt as the cathode 5 to the electrolytic tank 8, In the case where the cathode 5 made of SUS (stainless steel) is provided, water is electrolyzed in the electrolytic cell 8 in a flowing water system, and the result of measuring the difference in the amount of generated hydrogen peroxide due to the difference in the cathode 5 is shown. The used water is obtained by dissolving Na ₂ SO ₄ in pure water and having conductivity equivalent to tap water. The cathode 5 used had a mesh structure. In the figure, ● represents the hydrogen peroxide concentration with respect to the electrolysis voltage in the produced water in the cathode chamber 10 when the cathode 5 is formed of SUS, and ▼ represents the concentration of the produced water in the cathode chamber 10 when the cathode 5 is formed of Pt. The hydrogen peroxide concentration with respect to the electrolysis voltage, and は indicates the current value with respect to the electrolysis voltage when the cathode 5 was formed of SUS,
▽ indicates a current value with respect to an electrolytic voltage when the cathode 5 is formed of Pt.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C25B 11/02 C02F 1/46 101Z 11/04 C25B 9/00 LF term (reference) 4D037 AA02 AA05 AA11 BA18 BB01 CA04 CA11 CA12 4D050 AA02 AA04 AA12 BB09 BC07 BC09 BD04 BD08 CA10 4D061 DA02 DA03 DA08 DB09 EA04 EB01 EB04 EB12 EB17 EB20 EB28 EB30 EB31 EB35 EB39 ED06 FA07 FA16 GC12 GC01 4K011 DB02 DC15

Claims (12)

[Claims] 1. A method according to claim 1, wherein water is supplied into a cathode chamber of an electrolytic cell having a diaphragm provided between the anode chamber and the cathode chamber, and dissolved oxygen in the water is electrolytically reduced in the cathode chamber to generate hydrogen peroxide. A water purification device for purifying water by decomposing impurities in water by generated hydrogen peroxide or active oxygen derived from the hydrogen peroxide, and is formed of a simple substance or an alloy having low hydrogen generation efficiency during electrolysis. A water purification device comprising a cathode arranged in a cathode chamber. 2. The water purification apparatus according to claim 1, wherein the cathode is formed in a mesh structure. 3. The water purification device according to claim 1, wherein a plurality of cathodes are provided. 4. The water purifier according to claim 1, wherein a partition plate is provided in the cathode chamber to form a water channel structure. 5. A water purifying apparatus according to claim 1, further comprising means for increasing the concentration of dissolved oxygen in water supplied to the cathode chamber. 6. The water purification apparatus according to claim 5, further comprising means for increasing the dissolved oxygen concentration of water supplied into the cathode chamber by mixing air into the cathode chamber. 7. The apparatus according to claim 5, further comprising means for increasing the dissolved oxygen concentration of the water supplied to the cathode chamber by bubbling air into the water before being supplied to the cathode chamber. A water purification device as described in the above. 8. A cathode having a network structure is formed by weaving a hollow wire having pores, and air is supplied to the hollow portion of the wire during electrolysis so that air is sent from the pores into the cathode chamber. The water purification apparatus according to claim 5, wherein the means for increasing the concentration of dissolved oxygen in the water supplied to the cathode chamber is formed. 9. A method comprising: means for increasing the dissolved oxygen concentration of water supplied to the cathode chamber by anodic electrolysis of water before being supplied to the cathode chamber to generate oxygen. The water purification device according to claim 5. 10. The water according to claim 1, wherein a mechanism for generating active oxygen from hydrogen peroxide in the water is arranged in a flow path of the water downstream of the cathode chamber. Purification device. 11. A mechanism for generating active oxygen from hydrogen peroxide in water by providing a mesh-like metal in a flow path of water on the downstream side of the cathode chamber. Water purification equipment. 12. A mechanism for generating active oxygen from hydrogen peroxide in water by providing an ultraviolet irradiation unit for irradiating ultraviolet light to water flowing downstream of the cathode chamber. The water purification device according to claim 10.