JP4249658B2 - Electrolyzed water generator - Google Patents

Description

  The present invention applies electrolysis water by applying a DC voltage to a pair of electrodes provided in a pair of electrolysis chambers arranged opposite to each other via an ion-permeable diaphragm and electrolyzing raw water supplied to each electrolysis chamber. It is related with the electrolyzed water generating apparatus which obtains.

  Conventionally, an electrode is provided in a pair of electrolytic chambers arranged opposite to each other with an ion-permeable diaphragm, spaced apart from the ion-permeable diaphragm, and a DC voltage is applied between both electrodes to be supplied to each electrolytic chamber. There is known an electrolyzed water generating device for electrolyzing the raw water. According to the electrolyzed water generating device, drinking alkaline electrolyzed water can be obtained from the cathode-side electrolysis chamber by adjusting the voltage applied between both electrodes (see, for example, Patent Document 1).

However, in the electrolyzed water generating apparatus, if free chlorine is mixed in the process of generating alkaline electrolyzed water, trihalomethane such as chloroform may be generated in the electrolysis chamber and mixed into the drinking alkaline electrolyzed water.
JP-A-7-31980

  An object of the present invention is to provide an electrolyzed water generating apparatus that can eliminate such inconvenience and obtain drinking alkaline electrolyzed water and that does not generate trihalomethane in the electrolysis chamber.

In order to achieve such an object, the present invention provides a pair of electrolysis chambers arranged opposite to each other with an ion-permeable diaphragm, raw water supply means for supplying raw water to each electrolysis chamber, and each electrolysis with the diaphragm interposed therebetween. Electrolysis that takes out electrolyzed water obtained by electrolyzing raw water supplied to each electrolysis chamber by applying a DC voltage to the electrodes and a pair of electrodes provided in the chamber, and from each electrolysis chamber In an electrolyzed water generating apparatus comprising a water extraction means, the cation exchange membrane as the ion permeable diaphragm is provided in close contact with the surface of the cation exchange membrane at least in the electrolysis chamber on the cathode side. The electrode comprises a paste-like electrode material obtained by dispersing a catalyst made of platinum black or iridium black in an electrode base material made of a titanium compound, and further mixing with a binder. Paint on the surface of the ion exchange membrane And heating a porous body formed by pressurizing, raw water supply means, characterized in that it comprises a cathode-side raw water supply means for supplying purified water to the electrolysis chamber of at least the cathode side.

In the electrolyzed water generating apparatus of the present invention, an electrode is provided in close contact with the surface of the cation exchange membrane in the electrolysis chamber on the cathode side, and activated carbon and hollow are provided from the cathode side raw water supply means. Purified water treated with yarn film is supplied. The purified water is obtained by treating raw water containing chlorine such as tap water with activated carbon and a hollow fiber membrane. Further, the electrode comprises a paste-like electrode material obtained by dispersing a catalyst made of platinum black or iridium black in an electrode base material made of a titanium compound, and further mixing with a binder . It is a porous body formed by applying to the surface, heating and pressurizing.

  On the other hand, the anode-side electrolysis chamber may be provided with an electrode provided in close contact with the surface of the cation exchange membrane in the same manner as the cathode-side electrolysis chamber. And a mesh-like or porous solid electrode provided separately from each other. The electrolytic chamber on the anode side may be supplied with raw water containing a chloride aqueous solution such as saline and chlorine such as tap water by the raw water supply means, and the raw water is made up of activated carbon and a hollow fiber membrane. Treated purified water may be supplied.

Therefore, when a DC voltage is applied to the pair of electrodes provided in both the electrolysis chambers, oxygen (O ₂ ) and hydrogen ions are electrolyzed in the electrolysis chamber on the anode side by water electrolysis, as shown in Equation (1). (H ⁺ ) is generated. When the raw water contains chlorine, chlorine (Cl ₂ ) is generated from chlorine ions (Cl ⁻ ) as shown in the formula (2).

前記陽極側の電解室で生成した水素イオンの一部は、前記陽イオン交換膜を透過して、前記陰極側の電解室に移動するが、塩素イオンは陰イオンであるので前記陽イオン交換膜を透過することができず、該陽極側の電解室にとどまっている。

Some of the hydrogen ions generated in the anode-side electrolysis chamber permeate the cation-exchange membrane and move to the cathode-side electrolysis chamber, but chlorine ions are anions, so the cation-exchange membrane , And remains in the electrolytic chamber on the anode side.

On the other hand, in the electrolysis chamber on the cathode side, as shown in equations (3) and (4), hydrogen (H ₂ ) and hydroxide ions (OH ⁻ ) are generated by water electrolysis, while the cation exchange is performed. Hydrogen ions moving from the anode-side electrolysis chamber through the membrane are reduced to hydrogen in the vicinity of the electrode provided in close contact with the surface of the cation exchange membrane.

このとき、前記電極が前記陽イオン交換膜の表面に密着して形成されていることにより、式（３）で示される水の電解と、式（４）で示される水素イオンの還元とでは、式（４）の水素イオンの還元反応の方が支配的になり、式（３）による水酸イオンの生成が抑制される。

At this time, since the electrode is formed in close contact with the surface of the cation exchange membrane, electrolysis of water represented by the formula (3) and reduction of hydrogen ions represented by the formula (4) The reduction reaction of the hydrogen ion of formula (4) becomes more dominant, and the production of hydroxide ions by formula (3) is suppressed.

  Further, the purified water supplied from the cathode side raw water supply means adsorbs and removes chlorine and organic matter by the activated carbon, and filters the microorganisms such as relatively large molecules other than ions and fine molecules and bacteria by the hollow fiber membrane. To be removed. Further, even when raw water containing chlorine ions flows into the electrolytic chamber on the anode side, the chlorine ions cannot pass through the cation exchange membrane, so that chlorine ions do not flow into the electrolytic chamber on the cathode side. . Further, chlorine (molecules) or hypochlorous acid generated in the electrolytic chamber on the anode side cannot pass through the cation exchange membrane, and therefore does not flow into the cathode side. Therefore, free chlorine does not flow into the electrolysis chamber on the cathode side, and the conditions for producing trihalomethane are not satisfied.

As a result, according to the electrolyzed water generating device of the present invention, trihalomethane is not generated in the electrolysis chamber on the cathode side, and it is possible to obtain weak alkaline electrolyzed water rich in hydrogen (H ₂ ) and suitable for drinking. it can. In recent studies, it has been noted that hydrogen contained in the weak alkaline electrolyzed water has a significant effect on the health of the weak alkaline electrolyzed water (healthy bowel action, etc.). ing.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a system configuration diagram showing a configuration example of the electrolyzed water generating device of the present embodiment, and FIGS. 2 to 3 are explanatory sectional views and diagrams showing other configuration examples of the electrolyzed water generating device of the present embodiment. 4 is an explanatory cross-sectional view showing a configuration example of an electrolyzed water generating apparatus of a comparative example.

  As shown in FIG. 1, the electrolyzed water generating apparatus 1 according to this embodiment includes an electrolytic cell 5 including an anode-side electrolysis chamber 3 and a cathode-side electrolysis chamber 4 that are arranged to face each other with a cation exchange membrane 2 interposed therebetween. The anode side electrolysis chamber 3 is provided with an anode side electrode 6 spaced from the surface of the cation exchange membrane 2, and the cathode side electrolysis chamber 4 is in close contact with the surface of the cation exchange membrane 2 so as to be integrated with the cathode. A side electrode 7 is provided. The electrodes 6 and 7 are connected to the power supply device 8, and a DC electrode is applied between the electrodes 6 and 7.

  The electrolyzed water generating apparatus 1 includes raw water supply means 9, and the raw water supply means 9 branches from a main conduit 10 that supplies tap water, and an anode-side raw water supply conduit 11 that supplies raw water to the anode-side electrolysis chamber 3, and a main conduit The cathode side raw water supply conduit 12 is branched from 10 and supplies raw water to the cathode side electrolysis chamber 4. The anode-side raw water supply conduit 11 is provided with a salt solution adding device 13 in the middle so that the salt concentration of the raw water can be adjusted. The salt solution adding device 13 includes a salt solution tank 14 and a pump 15, and adds salt solution from the salt solution tank 14 to the anode side raw water supply conduit 11 via the pump 15.

  On the other hand, the cathode side raw water supply conduit 12 includes a filter 16 in the middle. The filter 16 includes an activated carbon filter that adsorbs and removes chlorine and organic substances in tap water, and a hollow fiber membrane filter that removes relatively large molecules and microorganisms. The purified water thus removed is supplied to the cathode side electrolysis chamber 4 as raw water. The filter 16 is provided with a drinking water conduit 17 separately from the cathode side raw water supply conduit 12, and the purified water is taken out from the filter 16 through the drinking water conduit 17 and used for drinking as it is.

  The electrolytic cell 5 includes an acidic electrolyzed water extraction conduit 18 that extracts acidic electrolyzed water from the anode-side electrolysis chamber 3 and an alkaline electrolyzed water extraction conduit 19 that extracts alkaline electrolyzed water from the cathode-side electrolysis chamber 4. The alkaline electrolyzed water extraction conduit 19 is connected to the drinking water conduit 17 via a three-way valve 20, and the drinking water conduit 17 is obtained from the purified water supplied from the filter 16 by the three-way valve 20 and from the cathode side electrolysis chamber 4. The alkaline electrolyzed water supplied can be switched freely.

  The anode side electrode 6 is a mesh-like or porous solid electrode, and for example, a titanium wire net covered with platinum and iridium can be used.

  The cathode side electrode 7 is obtained by dispersing a catalyst such as platinum black or iridium black on an electrode base material made of a titanium compound such as titanium carbide (TiC) or titanium nitride (TiN), and further mixing with a binder. It is a porous body formed by applying the paste-like body to the surface of the cation exchange membrane 2 in a predetermined shape, and heating and pressurizing. Examples of the binder include polymers such as polyvinyl alcohol (PVA), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), polystyrene (PS), and cellulose acetate (CA).

  In the electrolyzed water generating apparatus 1, a predetermined concentration of saline is supplied from the anode side raw water supply conduit 11 to the anode side electrolysis chamber 3, and chlorine, organic matter, and the like are substantially supplied from the cathode side raw water supply conduit 12 to the cathode side electrolysis chamber 4. Supply clean water that does not contain water. Then, by applying a predetermined DC voltage between the electrodes 6 and 7 by the power supply device 8 and performing electrolysis, the alkaline electrolyzed water extraction conduit 19 is free from the mixing of trihalomethane by the electrolysis and is rich in hydrogen and suitable for drinking. The weakly alkaline (for example, pH 9 or less) electrolyzed water can be taken out. Moreover, in the electrolyzed water generating apparatus 1, it is possible to take out weakly acidic (for example, pH 3 or higher) electrolyzed water containing moderate hypochlorous acid and having sterilizing power from the acidic electrolyzed water outlet conduit 18 by the electrolysis.

  Even if the anode side electrode 6 is arranged at a position in contact with the surface of the cation exchange membrane 2 by devising the structure such as using a mesh-like or porous solid electrode, the cation exchange membrane 2 The same effect as the case where it arrange | positions away from the surface of this can be anticipated.

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

  In this example, electrolyzed water was generated using the electrolyzed water generating device 21 having the configuration shown in FIG. The electrolyzed water generating device 21 is a simplification of the electrolyzed water generating device 1 shown in FIG. 1, and is composed of an anode side electrolysis chamber 3 and a cathode side electrolysis chamber 4 that are arranged to face each other with a cation exchange membrane 2 interposed therebetween. An electrolytic cell 5 is provided, the anode side electrolysis chamber 3 is provided with an anode side electrode 6 spaced from the surface of the cation exchange membrane 2, and the cathode side electrolysis chamber 4 is integrated with the surface of the cation exchange membrane 2. The cathode side electrode 7 is provided in close contact. The electrodes 6 and 7 are connected to the power supply device 8.

  The anode-side electrolysis chamber 3 includes an anode-side raw water supply conduit 11 that supplies a saline solution having a predetermined concentration separately prepared as raw water by a pump (not shown), and an acidic electrolyzed water extraction conduit 18 that extracts acidic electrolyzed water obtained by electrolysis. It has. The cathode-side electrolysis chamber 4 includes a cathode-side raw water supply conduit 12 that supplies purified water from which chlorine and organic substances have been substantially removed as raw water by a pump (not shown), and alkaline electrolyzed water that extracts alkaline electrolyzed water obtained by electrolysis. And an extraction conduit 19.

  In the electrolyzed water generating apparatus 21, the cation exchange membrane 2 is Nafion (registered trademark) 117 manufactured by DuPont, and the anode side electrode 6 is a solid electrode obtained by coating a titanium wire net with platinum and iridium. Moreover, the cathode side electrode 7 consists of the electrode base material which consists of 325 mesh or less titanium carbide (TiC), the catalyst which mixed platinum black and iridium black by the weight ratio of 3: 7, and 2% -polyvinyl alcohol solution. A paste-like mixture prepared by mixing the binder with a weight ratio of 100: 5: 7 is applied on the cation exchange membrane 2 and dried, and then heated and pressurized at 80 ° C. and 10 MPa for 30 minutes. It is formed by.

Next, 0.01 M saline was supplied from the anode-side raw water supply conduit 11 to the anode-side electrolysis chamber 3 at a flow rate of 100 ml / min, and chlorine and organic substances were substantially removed from the cathode-side raw water supply conduit 12. Clean water was supplied to the cathode-side electrolysis chamber 4 at a flow rate of 100 ml / min, and the power supply device 8 applied a DC voltage of 5 V between the electrodes 6 and 7 for electrolysis. The current density was 30 mA / cm ² .

  As a result, alkaline electrolyzed water suitable for drinking was obtained from the alkaline electrolyzed water extraction conduit 19 at pH 8.4 and substantially free of trihalomethane. On the other hand, acid electrolyzed water having an effective chlorine concentration of 25 to 30 ppm and a pH of 3.4 was obtained from the acid electrolyzed water extraction conduit 18.

  In this example, electrolyzed water was generated using the electrolyzed water generating device 22 having the configuration shown in FIG. The electrolyzed water generating device 22 is exactly the same as the electrolyzed water generating device 21 shown in FIG. 2 except that an anode side electrode 23 is provided in close contact with the surface of the cation exchange membrane 2 in the anode side electrolysis chamber 3. It has a configuration. The anode side electrode 23 is formed in exactly the same way as the cathode side electrode 7 of the first embodiment.

Next, electrolysis was performed in exactly the same manner as in Example 1 except that the electrolyzed water generating device 22 was used. The current density was 126 mA / cm ² .

  As a result, alkaline electrolyzed water having a pH of 8.7 and containing substantially no trihalomethane and suitable for drinking was obtained from the alkaline electrolyzed water extraction conduit 19. On the other hand, acidic electrolyzed water having a pH of 3.4 was obtained from the acidic electrolyzed water extraction conduit 18, but the acidic electrolyzed water had an effective chlorine concentration of 1 ppm or less and was hardly sterilizing.

  In this comparative example, water electrolysis is dominant in both the electrolysis chambers 3 and 4, and it is considered that the oxidation reaction of chlorine ions hardly occurs in the anode side electrolysis chamber 3.

In this example, electrolysis was performed in exactly the same way as in Example 1 except that the electrolyzed water generating device 22 was used and the concentration of the saline supplied from the anode side raw water supply conduit 11 to the anode side electrolysis chamber 3 was 0.002M. Went. Although the concentration of the saline solution was very dilute and close to the purified water, the current density was 120 mA / cm ² and electrolysis was sufficiently possible.

As a result, alkaline electrolyzed water suitable for drinking was obtained from the alkaline electrolyzed water extraction conduit 19 at pH 8.4 and substantially free of trihalomethane. On the other hand, acidic electrolyzed water having a pH of 3.8 was obtained from the acidic electrolyzed water extraction conduit 18, but the acidic electrolyzed water has a free chlorine concentration of 0.2 ppm or less. It is considered that the oxidation reaction has not occurred.
[Comparative Example 1]
In this comparative example, electrolyzed water was generated using the electrolyzed water generating device 24 having the configuration shown in FIG. The electrolyzed water generating device 24 is exactly the same as the electrolyzed water generating device 21 shown in FIG. 2 except that the cathode side electrolysis chamber 4 is provided with a cathode side electrode 25 spaced from the surface of the cation exchange membrane 2. It has a configuration. The cathode side electrode 25 is the same solid electrode as the anode side electrode 6 of the first embodiment.

Next, electrolysis was carried out in exactly the same manner as in Example 1 except that the electrolyzed water generating device 24 was used, but the current density was ² to 4 mA / cm ² , the electrolysis efficiency was low, and the electrolyzed water was substantially reduced. Could not get.

Therefore, electrolysis was performed in exactly the same manner as in Example 1 except that the electrolyzed water generating device 24 was used and a DC voltage of 15 V was applied between the electrodes 6 and 7 by the power supply device 8. The current density was 50 mA / cm ² .

  As a result, an acidic electrolyzed water having an effective chlorine concentration of 30 to 35 ppm and a pH of 2.7 was obtained from the acidic electrolyzed water outlet conduit 18, but the alkaline electrolyzed water obtained from the alkaline electrolyzed water outlet conduit 19 has a pH of 10 .7 was unsuitable for drinking. Alkaline electrolyzed water has been reported to have an increased blood potassium concentration due to drinking when the pH is 10 or more, and is considered unsuitable for drinking.

  In this example, electrolyzed water was generated using the electrolyzed water generating apparatus 1 having the configuration shown in FIG. The electrolyzed water generating apparatus 1 includes the cation exchange membrane 2, the anode side electrode 6, and the cathode side electrode 7 that are exactly the same as the electrolyzed water generating apparatus 21 shown in FIG.

Next, 0.01 M saline was supplied from the anode-side raw water supply conduit 11 to the anode-side electrolysis chamber 3 at a flow rate of 250 ml / min, and chlorine and organic substances were substantially removed from the cathode-side raw water supply conduit 12. Clean water was supplied to the cathode-side electrolysis chamber 4 at a flow rate of 250 ml / min, and a 5 V DC voltage was applied between the electrodes 6 and 7 by the power supply device 8 for electrolysis. The pH of tap water was 7.1 and the current density was 30 mA / cm ² .

  As a result, alkaline electrolyzed water having a pH of 8.3 and containing substantially no trihalomethane and suitable for drinking was obtained from the alkaline electrolyzed water extraction conduit 19. On the other hand, acidic electrolyzed water having an effective chlorine concentration of 26 ppm and a pH of 3.4 was obtained from the acidic electrolyzed water outlet conduit 18.

  In Examples 1 to 4, the saline solution is supplied to the anode side electrolysis chamber 3, but in the electrolyzed water generator of the present invention, at least the cathode side electrolysis chamber 4 is fed with raw carbon and activated carbon and hollow fibers. What is necessary is just to supply the purified water processed with the film | membrane etc., What kind of raw | natural water may be supplied to the anode side electrolysis chamber 3 may be sufficient. For example, the anode-side electrolysis chamber 3 may be supplied with raw water containing chlorine such as tap water and the saline solution, or may be supplied with the same purified water as that supplied to the cathode-side electrolysis chamber 4.

The system block diagram which shows the example of 1 structure of the electrolyzed water generating apparatus of this invention. Explanatory sectional drawing which shows the other structural example of the electrolyzed water generating apparatus of this invention. Explanatory sectional drawing which shows the further another structural example of the electrolyzed water generating apparatus of this invention. Explanatory sectional drawing which shows the example of 1 structure of the electrolyzed water generating apparatus of a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrolyzed water production | generation apparatus, 2 ... Ion-permeable separation membrane (cation exchange membrane), 4 ... Electrode chamber of a cathode side, 7 ... Electrode, 12 ... Cathode side raw | natural water supply means, 18, 19 ... Electrolyzed water extraction means.

Claims (3)

A pair of electrolysis chambers disposed opposite to each other with an ion-permeable diaphragm, raw water supply means for supplying raw water to each electrolysis chamber, a pair of electrodes provided in each electrolysis chamber with the diaphragm interposed therebetween, In an electrolyzed water generating apparatus comprising: an electrolyzed water extraction means for taking out electrolyzed water obtained by applying direct current voltage to the electrodes and electrolyzing raw water supplied to each electrolyzing chamber by the raw water supplying means;
A cation exchange membrane as the ion permeable diaphragm, and an electrode provided in close contact with the surface of the cation exchange membrane at least in the electrolysis chamber on the cathode side,
The electrode is obtained by dispersing a catalyst made of platinum black or iridium black on an electrode base material made of a titanium compound, and further mixing a paste-like electrode material obtained by mixing with a binder on the surface of the cation exchange membrane. It is a porous body formed by applying, heating and pressing,
The raw water supply means comprises a cathode-side raw water supply means for supplying purified water to at least the cathode-side electrolysis chamber.   The electrolyzed water generating apparatus according to claim 1, wherein the purified water is obtained by treating raw water containing chlorine with activated carbon and a hollow fiber membrane. 3. The electrolyzed water generating device according to claim 1, wherein a mesh-like or porous solid electrode provided separately from the cation exchange membrane is provided in the anode-side electrolysis chamber.

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