JP2008150665A - Method for producing ozone water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing ozone water which can simply and inexpensively recover the fatigue with elapsed time of a cation-exchange membrane and remove a stain component. <P>SOLUTION: The method of producing the ozone water comprises pressing an anode 22 to one face of the cation-exchange membranes 21a to 21c, pressing a cathode 23 to the other face, supplying water to the anode 22 and the cathode 23, and applying a direct-current voltage between the anode 22 and the cathode 23, wherein the ozone water is produced by applying a direct-current voltage with positive polarity to the cation-exchange membranes 21a to 21c which have absorbed water while the water has been supplied to the anode 22 and the cathode 23, and then stopping the current for a fixed period of time or longer, and applying a direct-current voltage with reverse polarity to give displacement to the cation-exchange membranes 21a to 21c. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for generating ozone water that can prevent deterioration in membrane performance due to fatigue over time and adhesion of impurities in a cation exchange membrane.

Currently, the ozone water production method widely used for industrial purposes is roughly divided into a gas dissolution method for dissolving in ozone gas generated by discharge, an electrolytic gas dissolution method for dissolving ozone gas generated by electrolysis in water, and raw water on the electrolytic surface. Three methods of direct electrolysis (for example, refer to Patent Document 1) in which ozone water is generated by direct contact are put into practical use. It is known that the direct electrolysis method can generate high-concentration ozone water by a simpler method than the gas dissolution method and the electrolytic gas dissolution method.
Specifically, such a direct electrolysis method divides the inside of the casing into an anode chamber and a cathode chamber by a solid electrolyte membrane, an anode electrode on the surface of the solid electrolyte chamber on the anode chamber side, and a solid electrolyte membrane on the cathode chamber side Using a device in which the cathode electrode is pressed on the surface, ozone water is generated by supplying water to the anode chamber and the cathode chamber and applying a DC voltage between the anode electrode and the cathode electrode. Yes.
However, when the ozone water generation operation is continued in the above apparatus, a phenomenon has been observed in which the concentration of ozone water gradually decreases. It is known that this is because the performance of the membrane deteriorates due to the disorder of the molecular arrangement of the solid electrolyte membrane little by little by continuous operation. Further, there is a problem that due to the continuous operation, dirt components such as calcium and magnesium (mainly hardness components) adhere to the surface of the cathode side of the solid electrolyte membrane, and the ozone water generation efficiency is also inhibited by these dirt components.
Therefore, in order to prevent the deterioration of the performance of the solid electrolyte membrane itself, both the anode electrode and the cathode electrode are provided so that they can be pressed and detached from the solid electrolyte membrane by a hydraulic cylinder, and the hydraulic cylinder is operated forward when a DC voltage is applied. The anode and cathode electrodes are pressed against the solid electrolyte membrane, and when the DC voltage is turned off, the hydraulic cylinder is retracted to separate the anode and cathode electrodes from the solid electrolyte membrane, so that the solid electrolyte membrane can be used again for electrolysis. There is a technique for stopping for a predetermined period of time when a recovery state is possible (see, for example, Patent Document 2).
JP-A-8-134678 Japanese Patent Laid-Open No. 11-172482

However, in the apparatus described in Patent Document 2, mechanical means such as a hydraulic cylinder is required to press and release the anode electrode and the cathode electrode from the solid electrolyte membrane, so that the apparatus is extremely complicated, large, and expensive. There is a problem of becoming.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ozone water generation method capable of easily and inexpensively recovering fatigue over time of a cation exchange membrane and removing dirt components. .

In order to solve the above problem, the invention of claim 1 is, for example, as shown in FIG.
The anode electrode 22 is pressed against one surface of the cation exchange membranes 21a to 21c, the cathode electrode 23 is pressed against the other surface, water is supplied to the anode electrode and the cathode electrode, and the anode electrode and the cathode electrode are supplied. In the ozone water generation method of generating ozone water by applying a DC voltage between
After generating ozone water by applying a positive direct current voltage to the cation exchange membrane that has become water-absorbed by supplying water to the anode electrode and the cathode electrode, a non-energization time of a certain time or more is provided. The cation exchange membrane is displaced by applying a DC voltage having a reverse polarity.

According to the first aspect of the present invention, after generating ozone water by applying a positive direct current voltage to the water-absorbed cation exchange membrane, a non-energization time of a certain time or more is allowed, and a reverse polarity direct current is applied. By applying voltage, electrical stimulation is given to the cation exchange membrane without disturbing the molecular arrangement of the cation exchange membrane, and the disturbance of the molecular arrangement of the cation exchange membrane is corrected by electrostriction. The original membrane performance can be restored. As a result, it is possible to recover the fatigue of the cation exchange membrane over time and remove soil components such as calcium and magnesium adhering to the cation exchange membrane. As a result, the ozone water generation efficiency can be improved without degrading the performance of the cation exchange membrane. Further, unlike the conventional case, no mechanical means such as a hydraulic cylinder is required, the apparatus is simplified, the size can be reduced, and the apparatus can be manufactured at low cost.
When a reverse polarity DC voltage is applied without leaving the current-carrying time, the molecular arrangement of the cation exchange membrane is further disturbed, and then the positive polarity DC voltage is applied to generate ozone water. This is because the performance may be deteriorated or the performance may not be recovered.

Invention of Claim 2 is the ozone water production | generation method of Claim 1,
The non-energization time of the predetermined time or longer is 1 minute or longer.

  According to the second aspect of the present invention, when an electrostriction phenomenon is caused by applying a DC voltage having a reverse polarity after the non-energization time by setting a non-energization time of 1 minute or more, the cation exchange membrane is not energized. During the (pause time), it enters a state where it tries to return to a normal state. When a DC voltage of reverse polarity is applied, the molecular arrangement of the cation exchange membrane is corrected correctly, and when ozone water is generated by applying a positive DC voltage, fatigue with time and removal of dirt components are eliminated. Can be recovered until it shows performance close to the initial state.

Invention of Claim 3 is the ozone water production | generation method of Claim 1 or 2,
A plurality of the cation exchange membranes are stacked.

  According to the invention of claim 3, since a plurality of the cation exchange membranes are stacked, the electrostriction phenomenon seen when a reverse polarity DC voltage is applied is the same thickness of the cation exchange membranes. Compared to the case of using the film, the case of using a plurality of thin films is greatly displaced, and it becomes easier to remove dirt. In particular, since most of the soil components such as calcium and magnesium adhere to the cathode electrode side of the membrane in contact with the cathode electrode, it is necessary to use a thin cation exchange membrane for the membrane in contact with the cathode electrode. It is effective.

Invention of Claim 4 is the ozone water production | generation method of Claim 3,
The plurality of cation exchange membranes are different in mass from each other.

A thick cation exchange membrane is advantageous in generating ozone because it has a high electrical resistance and maintains a high voltage. On the other hand, a thin film is advantageous in order to remove the adhered dirt using the electrostriction phenomenon. In order to realize both of these, it is effective to use a thick film for the cation exchange membrane on the anode electrode side that generates ozone and a thin film for the cation exchange membrane on the cathode electrode side.
According to the invention of claim 4, since the plurality of cation exchange membranes have different masses, it is possible to realize an ozone water generation method that is effective for both ozone generation and removal of attached dirt.

  Invention of Claim 5 is the ozone water production | generation method as described in any one of Claims 1-4. WHEREIN: The said electricity supply applies a pulse wave electric current, It is characterized by the above-mentioned.

  According to the fifth aspect of the invention, since the current is applied by applying the pulse wave current, the deterioration of the membrane performance of the cation exchange membrane can be further recovered by causing the electrostriction phenomenon repeatedly. In particular, it is effective for removing calcium and magnesium.

  Invention of Claim 6 is the ozone water production | generation method as described in any one of Claims 1-5. WHEREIN: The said anode electrode press-contacts to one surface of the said cation exchange membrane, and the said cathode electrode to the other surface The cation exchange membrane is held between the anode electrode and the cathode electrode, and the peripheral surfaces other than the anode electrode surface side and the cathode electrode surface side of the cation exchange membrane are free. It is characterized by being in a neutral state.

  According to invention of Claim 6, a cation exchange membrane is hold | maintained between an anode electrode and a cathode electrode, and the surrounding surfaces other than the anode electrode surface side and cathode electrode surface side of a cation exchange membrane are free states. Therefore, the displacement of the cation exchange membrane is not hindered, and the electrostriction phenomenon can easily occur.

  According to the present invention, recovery of fatigue over time of a cation exchange membrane and removal of attached dirt components can be performed easily and inexpensively, and the efficiency of ozone water generation can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a side cross-sectional view of the ozone water generating apparatus 100. (a) shows a case where the cation exchange membranes 21a to 21c are strongly pressed, and (b) shows a positive flow for facilitating electrostriction. The case where the ion exchange membranes 21a to 21c are lightly contacted is shown.
First, the ozone water generating apparatus 100 used in the ozone water generating method according to the present invention will be described. The ozone water generating device 100 is configured by arranging a catalyst electrode 2 in a casing 1 into which raw water (for example, tap water) flows, and is fine by applying a positive DC voltage to the catalyst electrode 2. Ozone bubbles are generated, ozone water is generated by dissolving fine ozone bubbles that are close to being generated in water, and after generation, a DC voltage having a reverse polarity is applied to the cation exchange membrane 21 of the catalyst electrode 2 over time. It is an apparatus that can recover from fatigue and remove dirt components.

Specifically, the casing 1 has a long cylindrical shape, and the catalyst electrode 2 is disposed at a substantially central portion in the casing 1, whereby the space in the casing 1 is divided into the anode chamber 11 </ b> A and the cathode chamber 11 </ b> B. It is partitioned. Further, an anode side supply port 12A that communicates with the anode chamber 11A and supplies water and a cathode side supply port 12B that communicates with the cathode chamber 11B and supplies water are formed at the upper end of the casing 1, respectively. Has been. An anode-side supply path 13A that communicates with the anode chamber 11A is formed at the anode-side supply port 12A, and a cathode-side supply path 13B that communicates with the cathode chamber 11B is formed at the cathode-side supply port 12B. The anode-side supply port 12A and the cathode-side supply port 12B are connected to, for example, a low discharge pressure small pump or a water tap connected to a tank in which water is stored (not shown).
On the other hand, the lower end portion of the casing 1 communicates with the anode chamber 11A, and discharges the anode-side discharge port 14A from which ozone water generated in the anode chamber 11A is discharged and hydrogen water generated in the cathode chamber 11B. The cathode side discharge port 14B is formed. An anode side discharge path 15A leading to the anode chamber 11A is formed at the anode discharge port 14A, and a cathode side discharge path 15B leading to the cathode chamber 11B is formed at the cathode side discharge port 14B. For example, although not shown, the anode-side drain port 14A is connected to a pump, a nozzle, or the like for connecting to a tank that stores ozone water generated in the casing 1. For example, although not illustrated, the cathode side drain port 14B is connected to a pump, a nozzle, or the like for connecting to a tank for storing hydrogen water generated in the casing 1.
An insertion hole 16 is formed in the inner wall surface of the casing 1 between the anode side supply port 12A and the cathode side supply port 12B, into which upper ends of a plurality of cation exchange membranes 21a to 21c described later are inserted. In the inner wall surface of the casing 1 between the anode side discharge port 14A and the cathode side discharge port 14B, an insertion hole 17 into which the lower ends of the plurality of cation exchange membranes 21a to 21c are inserted is formed.
In such a casing 1, water is supplied from the anode side supply port 12A and the cathode side supply port 12B, and passes through the anode side supply path 13A, the anode side discharge path 15A, the cathode side supply path 13B, and the cathode side discharge path 15B. A water flow is generated to the anode side outlet 14A and the cathode side outlet 14B.

The catalyst electrode 2 includes a plurality of cation exchange membranes 21a to 21c arranged to face each other, an anode electrode 22 pressed against one surface of the cation exchange membrane 21a facing the anode chamber 11A side, and a cation A cathode electrode 23 in pressure contact with the other surface of the exchange membrane 21c facing the cathode chamber side 11B.
A concave portion is formed in the inner wall surface of the casing 1 facing the anode chamber 11A side, and a holding plate 18A for holding the anode electrode 22 is attached in the concave portion, and the anode electrode 22 is held by the holding plate 18A. ing. Similarly, a recess is formed on the inner wall surface of the casing 1 facing the cathode chamber 11B side, and a holding plate 18B for holding the cathode electrode 23 is attached in the recess, and the cathode electrode 11B is attached to the holding plate 18B. Is retained. Combining members such as rubber and resin with appropriate spring constants on the rear surfaces of the holding plates 18A and 18B is preferable because it is excellent in ozone generation and can realize a contact pressure effective for reverse pole application described later.

  An output terminal 24 of a power supply device (not shown) is electrically connected between the anode electrode 22 and the cathode electrode 23 so that a DC voltage is applied. That is, the anode electrode 22 and the cathode electrode 23 are connected to the power supply device through the conductive wires to the electrodes 22 and 23. The DC voltage applied between the anode electrode 22 and the cathode electrode 23 is preferably 6 to 15 volts, for example, and is preferably a pulse wave current.

  As the plurality of cation exchange membranes 21a to 21c, conventionally known ones can be used, and a fluorine-based cation exchange membrane having a high durability against the generated ozone can be used. ˜300 μm is preferred. Moreover, the vertical length is longer than that of the anode electrode 22 and the cathode electrode 23, and the upper end portion and the lower end portion thereof are inserted into the insertion holes 16 and 17, respectively. Further, the plurality of cation exchange membranes 21a to 21c have different masses, for example, the cation exchange membrane 21a on the anode electrode 22 side is thick, and the cation exchange membrane 21c on the cathode electrode 23 side is thin. Is preferably used. Thereby, it is possible to provide an ozone generator 100 that is excellent in ozone generation and excellent in preventing pollution.

  The anode electrode 22 is preferably in the form of a woven mesh or a grating metal. Note that FIG. 1 shows the case where the anode 22 is a woven mesh. Specifically, the woven net shape is a thin wire rod woven in a lattice shape, and the grating metal shape is an integral lattice shape in which the wire rod is welded.

  As the anode electrode 22, a metal having an ozone generation catalyst function is used, and it is preferable to use an electrode of platinum or a platinum-coated metal as the metal.

  Thus, by using the woven net-like or grating-like anode electrode 22, the intersection part P of the members constituting the anode electrode 22 sharply protrudes to the outer surface, generates a vortex in contact with the water flow, and is generated at the anode electrode 22. Ozone bubbles can be involved to accelerate dissolution.

As the cathode electrode 23, it is preferable to use a metal such as platinum, silver, or titanium or a thin silver wire mesh whose surface is coated with silver chloride. The cathode electrode 23 is also preferably formed in a grating shape like the anode electrode 22. In particular, the cathode electrode 23 is preferably formed so as to have coarser eyes than the anode electrode 22.
The plurality of cation exchange membranes 21a to 21c, the anode electrode 22 and the cathode electrode 23 are formed in a flat plate shape, and the plurality of cation exchange membranes 21a to 21c, the anode electrode 22 and the cathode electrode 23 are formed. Are in close contact and pressure contact. Here, the junction pressures of the cation exchange membranes 21a to 21c and the anode electrode 22 and the cathode electrode 23 are in a state of being energized as shown in FIGS. The cation exchange membranes 21a to 21c are adjusted so as to be displaced by applying a direct current voltage. In other words, the state where electricity can be supplied is that the cation exchange membranes 21a to 21c are in contact with the anode electrode 22 and the cathode electrode 23, and it is preferable that the contact surface pressure is lowered and lightly contacted (for example, FIG. 1). (See (b)). The range in which the cation exchange membranes 21a to 21c can be displaced varies depending on the thickness of the cation exchange membranes, the number of stacked layers, etc., and is preferably determined while observing the ozone generation state and the electrostriction phenomenon.

  Then, by inserting the upper and lower ends of the cation exchange membranes 21a to 21c into the respective insertion holes 16, 17, the anode electrode 22 is fixed to the holding plate 18A, and the cathode electrode 23 is fixed to the holding plate 18B. A catalyst electrode 2 is mounted in the casing 1. Thus, the cation exchange membranes 21 a to 21 c are held between the anode electrode 22 and the cathode electrode 23, and the upper and lower ends of the cation exchange membranes 21 a to 21 c are fixed in the casing 1.

Next, an ozone water generation method using the ozone water generation apparatus 100 having the above-described configuration will be described.
Water is supplied into the casing 1 from the anode side supply port 12A and the cathode side supply port 12B, and water is continuously brought into contact with the surface of the anode electrode 22 and the surface of the cathode electrode 23. At the same time, a predetermined voltage is applied between the anode electrode 22 and the cathode electrode 23 by driving the power supply device. Water is electrolyzed by this energization, ozone bubbles are generated on the anode electrode 22 side, and hydrogen bubbles are generated on the cathode electrode 23 side. The generated ozone bubbles are dissolved in water to become ozone water and discharged from the anode side outlet 14A, and the hydrogen bubbles are dissolved in water to become hydrogen water and discharged from the cathode side outlet 14B.

  When ozone water is generated in this manner, a reverse polarity DC voltage is applied with a non-energization time of a certain time or more. For example, the predetermined time or longer is preferably 1 minute or longer. Here, positive polarity means that the anode electrode 22 is an anode and the cathode electrode 23 is a cathode, and reverse polarity means that the anode electrode 22 is a cathode and the cathode electrode 23 is an anode. Practically, using a means such as two electromagnetic contactors, forward / reverse switching is performed and a predetermined voltage is applied.

In addition, when changing the application of the positive polarity voltage and the reverse polarity voltage, for example, the positive polarity voltage is automatically changed to the reverse polarity voltage application for a predetermined time, and then the reverse polarity voltage is changed. It is preferable to set so that it is automatically changed to positive voltage application by applying for a predetermined time.
In this way, by applying a reverse polarity voltage from the positive polarity, the gelled cation exchange membranes 21a to 21c that have absorbed water are displaced in a micro state by short-time electrical stimulation. For this reason, the fatigue over time of the cation exchange membranes 21a to 21c is recovered, and adhered components such as calcium and magnesium are removed. Thereafter, by applying a positive voltage again, ozone water can be repeatedly generated without degrading the performance of the cation exchange membranes 21a to 21c.

As described above, according to the embodiment of the present invention, after ozone water is generated by applying a positive DC voltage to the cation exchange membranes 21a to 21c that have become in a water-absorbing state, no energization is performed for a predetermined time or more. By applying a DC voltage having a reverse polarity after a while, electrical stimulation is given without disturbing the molecular arrangement of the cation exchange membranes 21a to 21c, and the cation exchange membranes 21a to 21 are caused by electrostriction. The disorder of the molecular arrangement of 21c can be corrected and the original film performance can be restored. As a result, recovery of fatigue over time of the cation exchange membranes 21a to 21c and contamination components such as calcium and magnesium attached to the cation exchange membranes 21a to 21c can be removed. As a result, the efficiency of ozone water generation can be improved without degrading the performance of the cation exchange membranes 21a to 21c. In addition, it does not require mechanical means such as a hydraulic cylinder as in the prior art, and the apparatus is simplified and can be reduced in size and can be manufactured at low cost. By making it, the deterioration of the membrane performance of cation exchange membranes 21a-21c can be recovered more. In particular, it is effective for removing calcium and magnesium.

In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary, it can change suitably.
For example, in the above embodiment, three cation exchange membranes 21a to 21c are used. However, one or two cation exchange membranes 21a to 21c may be used, or four or more may be used.

  In the above embodiment, the upper and lower ends of the cation exchange membranes 21a to 21c are inserted and fixed in the insertion holes 16 and 17, but the upper and lower ends of the cation exchange membranes 21a to 21c are fixed. Instead of being inserted into the insertion holes 16 and 17, it is held only by the anode electrode 22 and the cathode electrode 23, and the peripheral surfaces other than the anode electrode surface 22 side and the cathode electrode surface 23 side of the cation exchange membranes 21a to 21c are free. It may be in a state. In this way, by setting the peripheral surfaces of the cation exchange membranes 21a to 21c in a free state, the displacement of the cation exchange membranes 21a to 21c is not hindered and can be held in a state in which electrostriction is likely to occur. it can.

Next, the Example by the ozone water production | generation method of this invention is described.
A platinum anode electrode was used, a cathode electrode in which silver was coated with silver chloride was used, and a DuPont naphth ion membrane was used for the three cation exchange membranes having different thicknesses. Then, a catalyst electrode in which these three cation exchange membranes, an anode electrode and a cathode electrode are overlapped and pressed is disposed at a predetermined position in the casing as shown in FIG. 1, and an anode side supply port and a cathode side supply port are arranged. Distilled water was supplied from the anode and a positive DC voltage of 12 V was applied between the anode electrode and the cathode electrode. As a result, a current of about 28 A flowed at a flow rate of 5 L / min, and 5 ppm of ozone water was obtained from the anode side outlet. . After 180 minutes, the concentration dropped to 4 ppm, so it was observed that after returning to the original 5 ppm ozone concentration by applying a DC voltage of reverse polarity for 1 second and applying electrical stimulation after a pause of 2 minutes It was done. That is, it is considered that the membrane performance of the cation exchange membrane deteriorated with time is restored by electrical stimulation, and calcium and magnesium adhering to the membrane surface are detached. Further, the length of the non-energization time can be considered depending on the degree of fatigue with time and dirt, but according to the above-mentioned experiment, it can be recognized that the recovery can be performed almost without problems if it is left for 2 minutes or longer. Therefore, the effect of the present invention is recognized.

It is a sectional side view of the ozone water generating apparatus 100, (a) shows a case where the cation exchange membranes 21a to 21c are strongly pressed, and (b) shows a cation exchange membrane 21a for facilitating electrostriction. The case where -21c is lightly contacted is shown.

Explanation of symbols

2 Catalytic electrodes 21a, 21b, 21c Cation exchange membrane 22 Anode electrode 23 Cathode electrode 100 Ozone water generator

Claims (6)

An anode electrode is pressed against one surface of the cation exchange membrane, a cathode electrode is pressed against the other surface, water is supplied to the anode electrode and the cathode electrode, and direct current is applied between the anode electrode and the cathode electrode. In the ozone water generation method for generating ozone water by applying a voltage,
After generating ozone water by applying a positive direct current voltage to the cation exchange membrane that has become water-absorbed by supplying water to the anode electrode and the cathode electrode, a non-energization time of a certain time or more is provided. The ozone water generation method is characterized in that the cation exchange membrane is displaced by applying a DC voltage having a reverse polarity.   The ozone water generation method according to claim 1, wherein the non-energization time of the predetermined time or longer is 1 minute or longer.   The ozone water generation method according to claim 1 or 2, wherein a plurality of the cation exchange membranes are stacked.   The ozone water generation method according to claim 3, wherein the plurality of cation exchange membranes have different masses.   The ozone water generating method according to any one of claims 1 to 4, wherein the energization applies a pulse wave current. The anode electrode is pressed against one surface of the cation exchange membrane, and the cathode electrode is pressed against the other surface, whereby the cation exchange membrane is held between the anode electrode and the cathode electrode. The peripheral surface other than the anode electrode surface side and the cathode electrode surface side of the cation exchange membrane is in a free state, ozone water according to any one of claims 1 to 5 Generation method.

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