JP2005144239A - Electrolytic cell and electrolytic water generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic cell and an electrolytic water generator which are small in size and excellent in electrolysis efficiency. <P>SOLUTION: The electrolytic cell has a pair of electrolytic chambers 10a, 10b arranged opposite to each other through an ion permeable diaphragm 2, raw water supply means 11a, 11b, a pair of electrodes 3a, 3b installed in the electrolytic chambers 10a, 10b respectively so as to put the diaphragm 2 between them, and electrolytic water taking out means 12a, 12b for taking out electrolytic water. The diaphragm 2 is a cation permeable membrane, and the electrodes 3a, 3b are stuck fast to both surfaces of the cation permeable membrane 2 to form a cation permeable membrane-electrode structure. Only raw water fed to the cathode-side electrolytic chamber 10b contains an electrolyte. The electrodes 3a, 3b are porous material made of conductive powder, or are formed in the shape of mesh or a comb. The electrodes 3a, 3b are formed by applying a conductive paste containing the conductive powder to the surface of the cation permeable membrane 2 and heating or pressurizing it. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, raw water supplied to a pair of electrolysis chambers opposed to each other through an ion-permeable diaphragm is applied to a pair of electrodes provided in each electrolysis chamber across the diaphragm. The present invention relates to an electrolytic cell for electrolysis and an electrolyzed water generating device for generating electrolyzed water using the electrolytic cell.

  Electrolyzed water for generating electrolyzed water using an electrolytic cell comprising a pair of electrolysis chambers arranged opposite to each other with an ion-permeable diaphragm and a pair of electrodes provided in each electrolysis chamber across the diaphragm Generation devices are known. In the electrolyzed water generator, raw water containing an electrolyte is supplied to each electrolysis chamber, and a voltage is applied to the pair of electrodes to electrolyze the raw water, whereby acidic electrolyzed water is supplied to the electrolysis chamber on the anode side, Alkaline electrolyzed water can be generated in the electrolysis chamber on the cathode side.

  In the electrolytic cell of the electrolyzed water generating device, the electrode is usually provided apart from the diaphragm. However, the above-described configuration has a problem in that since the distance between both electrodes disposed across the diaphragm is wide, the electrical resistance between the electrodes is large and the electrolysis efficiency with respect to the applied power is low.

  In order to solve the above problem, for example, the electrode between the porous electrode material made of plain woven wire mesh and the punched metal is brought into contact with the diaphragm to reduce the distance between both electrodes, and the porous electrode material There has been proposed an electrolytic cell in which the contact area between the raw water and the electrode is increased by circulating the raw water inside (see, for example, Patent Document 1).

However, in the electrolytic cell, although the electrolytic efficiency with respect to the applied power can be improved to some extent, it is not sufficient, and since the raw water is circulated inside the porous electrode material, the flow resistance is large. If an attempt is made to increase the amount of electrolyzed water generated per hour, there is an inconvenience that the size of the apparatus cannot be avoided.
JP 2001-73177 A

  An object of the present invention is to provide an electrolyzed water generator that eliminates such disadvantages and is small in size and excellent in electrolysis efficiency and generates electrolyzed water using the electrolyzer.

  In order to achieve the above object, an electrolytic cell of the present invention comprises a pair of electrolytic chambers arranged opposite to each other with ion-permeable diaphragms, raw water supply means for supplying raw water to each electrolytic chamber, and the diaphragms. A pair of electrodes provided in each electrolysis chamber, and electrolyzed water obtained by electrolyzing raw water supplied to each electrolysis chamber by applying a voltage to both electrodes by the raw water supply means In the electrolytic cell provided with the electrolyzed water extraction means for taking out from the membrane, the diaphragm is a cation exchange membrane, and the electrode is in close contact with both surfaces of the cation exchange membrane to form a membrane-electrode structure capable of transmitting a cation. It is characterized by that.

In the electrolytic cell of the present invention, raw water is supplied to each electrolysis chamber by the raw water supply means, and voltage is applied to electrodes formed on both surfaces of the cation exchange membrane to electrolyze the raw water. In this way, in the cathode-side electrolysis chamber, hydrogen gas by electrolysis of water and hydroxide ions (OH ⁻ ) are generated, and electrolyzed water that exhibits alkalinity by the hydroxide ions (hereinafter abbreviated as alkaline electrolyzed water). Is obtained). On the other hand, in the electrolysis chamber on the anode side, oxygen gas by hydrogen electrolysis and hydrogen ions (H ⁺ ) are generated, and electrolyzed water exhibiting acidity by the hydrogen ions (hereinafter abbreviated as acidic electrolyzed water) is obtained. . The alkaline electrolyzed water and the acidic electrolyzed water are each taken out from the electrolytic cell by the electrolyzed water extracting means.

  At this time, according to the electrolytic cell of the present invention, since both the electrodes are formed in close contact with both surfaces of the cation permeable membrane, the electrical resistance between the both electrodes is small, and the applied electric power Excellent electrolytic efficiency can be obtained.

On the other hand, in the electrolysis of water, it is known that there is a relationship represented by the following formula (1) between the standard oxidation-reduction potential E ⁰ and the actual electrode potential E.

E = E ⁰ −0.06 pH (1)
The standard redox potential E ⁰ is on the anode side.
_{2H 2 O = O 2 + 4H} + + 4e - E 0 = 1.23 (V)
And on the cathode side,
2H ⁺ + 2e ⁻ = H ₂ E ⁰ = 0 (V)
It becomes. Therefore, the formula (1) is represented by the following formula (2) on the anode side and is represented by the following formula (3) on the cathode side.

E = 1.23-0.06 pH (2)
E = −0.06 pH (3)
Here, in the electrolytic cell of the present invention, a part of the hydrogen ions generated in the electrolytic chamber on the anode side moves to the electrolytic chamber on the cathode side through the cation permeable membrane. As a result, in the electrolytic chamber on the anode side, hydrogen ions are deficient in the vicinity of the electrode formed in close contact with the cation permeable membrane, and the pH rises. In the electrolysis chamber on the cathode side, hydrogen ions are enriched in the vicinity of the electrode formed in close contact with the cation permeable membrane by hydrogen ions moving from the electrolysis chamber on the anode side, and the pH is lowered.

  As a result, the electrode potential E has a small absolute value in both the formulas (2) and (3), and electrolysis can be performed at a lower voltage, so that excellent electrolysis efficiency is obtained with respect to the applied power. be able to.

  When the alkaline electrolyzed water is used for drinking, if a chloride is used as the electrolyte, trihalomethane may be generated in the alkaline electrolyzed water due to the electrolysis. Therefore, a calcium compound containing no chlorine is used instead of chloride as the electrolyte. However, when the calcium compound is used, an increase in running cost is inevitable.

  However, according to the electrolytic cell of the present invention, excellent electrolysis efficiency can be obtained as described above. Therefore, electrolysis is possible even if the calcium compound as the electrolyte is reduced, and the running cost can be reduced. .

  In addition, according to the electrolytic cell of the present invention, since the electrode is formed integrally with the cation permeable membrane, the number of parts is small and the flow structure of raw water is simplified. As a result, since the flow resistance of the raw water is reduced, the amount of electrolyzed water generated per unit time is increased, and the apparatus can be miniaturized. Furthermore, according to the electrolytic cell of the present invention, the electrical resistance between the two electrodes is small as described above, and excellent electrolysis efficiency can be obtained. Therefore, the load on the power source is small, and the capacity of the power source can be reduced. it can.

  In the electrolytic cell of the present invention, the electrode is a porous body formed from conductive powder. Since the porous body has, for example, pores with a diameter of several μm, for example, even if the entire surface of the cation exchange membrane is covered with an electrode, the cation permeable membrane has an exposed portion facing the pore. It can be. As a result, the electrode can bring the hydrogen ions generated in the electrolytic chamber on the anode side into contact with the cation permeable membrane at the exposed portion, and in the vicinity of the surface of the cation permeable membrane in the electrolytic chamber on the cathode side. Thus, the hydrogen ions can be enriched.

  In the electrolytic cell of the present invention, the electrode may be formed in a mesh shape or a comb shape. In this case, the cation permeable membrane can have the mesh-shaped or comb-shaped gap as an exposed portion, and the mesh-shaped or comb-shaped electrode is an electrode made of the porous body with respect to the exposed portion. The same effect is obtained.

  In addition, as is generally known as the edge effect, in an electrode, current is concentrated at the end portion, and charge exchange is likely to occur. However, since the mesh-shaped or comb-shaped electrode has many portions serving as the end portion, This is advantageous in terms of the exchange and further excellent electrolysis efficiency can be obtained.

  Since the mesh-shaped or comb-shaped electrode can expose the cation permeable membrane from the shape to the mesh-shaped or comb-shaped gap, even if it is a dense solid that does not substantially include the pores. However, it may be a porous body formed from the conductive powder.

  The electrode made of a porous body formed from the conductive powder is formed by applying a conductive paste containing a conductive powder to the surface of the cation permeable membrane and heating or pressurizing it. It is characterized by that. The electrode can be easily formed into an arbitrary shape by applying the conductive paste to the surface of the cation permeable membrane by means such as printing, and is suitable for mass production. The electrode may be formed by either heating or pressurizing after the conductive paste is applied to the surface of the anion exchange membrane, and both means may be used to further pressurize after heating. You may form together.

  And the electrolyzed water generating apparatus of this invention produces | generates electrolyzed water using the said electrolytic vessel, It is characterized by the above-mentioned. According to the electrolyzed water generating apparatus of the present invention, it is possible to reduce the overall size and weight of the apparatus by providing the electrolyzer.

  Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. 1 is an assembly diagram of the electrolytic cell of the present embodiment, FIG. 2 is an explanatory sectional view of the membrane-electrode structure of the electrolytic cell shown in FIG. 1, and FIGS. 3 and 4 are other examples of the membrane-electrode structure. FIG.

  As shown in FIG. 1, the electrolytic cell 1 of the present embodiment includes a current collector plate 5 a on both sides of a membrane-electrode structure 4 in which film-like electrodes 3 a and 3 b are formed on both surfaces of a cation permeable membrane 2. , 5b, spacers 6a, 6b, and outer plates 7a, 7b are overlapped. The membrane-electrode structure 4, the current collector plates 5a and 5b, the spacers 6a and 6b, and the outer plates 7a and 7b are fastened by a bolt inserted through a through hole (not shown) and a nut screwed to the bolt.

  As shown in FIG. 2, the membrane-electrode structure 4 includes membrane electrodes 3 a and 3 b formed in a rectangular shape on both surfaces of the cation permeable membrane 2. As the cation permeable membrane 2, for example, an anion exchange membrane made of a hydrocarbon polymer such as Aciplex (registered trademark) manufactured by Asahi Kasei Kogyo Co., Ltd. or Ceremon (registered trademark) manufactured by Asahi Glass Co., Ltd. can be used. For the electrodes 3a and 3b, a metal powder such as platinum and iridium is mixed in a conductive powder such as carbon black at a ratio of 5% by weight with respect to the conductor powder, and polyvinyl alcohol is mixed with water and alcohol. The paste-like body to which the mixture dissolved in the mixed solution is applied is applied to both surfaces of the cation permeable membrane 2 in a predetermined shape, and is heated and pressurized so as to adhere to the cation permeable membrane 2, and the cation permeable membrane. 2 and one. Since the electrodes 3a and 3b are formed from the conductive powder and metal powder, the electrodes 3a and 3b are porous bodies having pores with a diameter of several μm, and the cation permeable membrane 2 has a portion facing the pores. Exposed. In the paste-like body, polyvinyl alcohol serves as both a binder and a solvent.

  In the membrane-electrode structure 4, the cation permeable membrane 2 has a thickness of 50 to 200 μm. The electrodes 3a and 3b are formed so that the dry film thickness is 30 to 200 μm by the above-described method.

  Returning to FIG. 1, the current collector plates 5 a and 5 b are made of a metal foil such as aluminum, and are provided with window portions 8 a and 8 b that expose the electrodes 3 a and 3 b at the center, and electrodes at the outer peripheral portions of the window portions 8 a and 8 b. It is in contact with 3a and 3b. The current collecting plates 5a and 5b are provided with terminal portions 9a and 9b drawn in different directions at the upper end portions, and are connected to the power supply device 14 by the conductive wires 13 through the terminal portions 9a and 9b.

  The spacers 6a and 6b are provided with hollow portions communicating with the window portions 8a and 8b of the current collector plates 5a and 5b at the center, and the hollow portions serve as the electrolytic chambers 10a and 10b. The spacers 6a and 6b are provided with water supply holes 11a and 11b for supplying raw water to the electrolysis chambers 10a and 10b, and drainage holes 12a and 12b for taking out electrolyzed water generated in the electrolysis chambers 10a and 10b. The water supply holes 11a and 11b are connected to raw water supply means such as a raw water tank (not shown), and the drain holes 12a and 12b are connected to a water storage tank and the like (not shown).

  The outer plates 7a and 7b are blind plates, and the electrolytic chambers 10a and 10b are formed by closing the hollow portions of the spacers 6a and 6b.

  In the electrolytic cell 1 of the present embodiment, for example, the electrode 3a is used as an anode, the electrode 3b is used as a cathode, and a calcium lactate aqueous solution is supplied as raw water containing electrolyte to the electrolytic chambers 10a and 10b via the water supply holes 11a and 11b. 14, the electrodes 3a and 3b are energized. As a result, acidic electrolyzed water is obtained in the electrolysis chamber 10a, and the acidic electrolyzed water is taken out through the drain hole 12a. On the other hand, alkaline electrolyzed water is obtained in the electrolysis chamber 10b, and the alkaline electrolyzed water is taken out through the drain hole 12b. In the electrolytic cell 1, since the calcium salt which does not contain chlorine like the said calcium lactate is used as the said electrolyte, the said alkaline electrolyzed water does not contain a trihalomethane and can be used suitably for drinking.

  At this time, the electrodes 3a and 3b are in close contact with both surfaces of the cation permeable membrane 2 and are formed integrally with the cation permeable membrane 2 and the distance between the two electrodes is very narrow. Electrolysis can be performed efficiently at a low voltage.

  In the embodiment, the membrane electrodes 3a and 3b made of a porous material are provided on both surfaces of the cation permeable membrane 2 in a rectangular shape. However, the electrodes 3a and 3b are limited to the above shapes. Instead, it may be mesh-shaped as shown in FIG. 3, or may be comb-shaped as shown in FIG. When the electrodes 3a and 3b are comb-shaped, as shown in FIG. 4, the electrode 3a and the electrode 3b (shown by hidden lines in FIG. 4) may be provided at positions that do not overlap each other.

  When the electrodes 3a and 3b are formed in the mesh or comb shape, the cation permeable membrane 2 is exposed from the mesh or comb-shaped gap, so that the electrodes 3a and 3b are not a porous body but a dense solid having no pores. It may be. However, in the case of a porous body similar to the electrodes 3a and 3b shown in FIG. 1, the mesh-like or comb-like shape can be obtained by applying the paste-like body to the cation permeable membrane 2 by a method such as screen printing. This is advantageous because the shape can be easily formed.

  Moreover, the electrolytic cell 1 of the said embodiment is equipped with peripheral devices, such as the power supply device 14 which supplies electric power to electrode 3a, 3b, and the control apparatus which controls operation | movement of the said raw | natural water supply means, etc., thereby providing an electrolyzed water generating apparatus. Can be configured.

The assembly drawing which shows the example of 1 structure of the electrolytic vessel which concerns on this invention. Explanatory sectional drawing of the membrane-electrode structure of the electrolytic cell shown in FIG. The top view which shows the other example of a membrane-electrode structure. The top view which shows the other example of a membrane-electrode structure.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Electrolytic cell, 2 ... Cation permeable membrane, 3a, 3b ... Electrode, 10a, 10b ... Electrolytic chamber, 11a, 11b ... Raw water supply means, 12a, 12b ... Electrolyzed water extraction means.

Claims (5)

A pair of electrolysis chambers opposed to each other via 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 electrolytic cell comprising electrolyzed water taken out from each electrolysis chamber by applying voltage to both electrodes and electrolyzing the raw water supplied to each electrolysis chamber by the raw water supply means,
The electrolytic cell, wherein the diaphragm is a cation exchange membrane, and the electrode is in close contact with both surfaces of the cation exchange membrane to form a membrane-electrode structure capable of transmitting cations.   The electrolytic cell according to claim 1, wherein the electrode is a porous body formed of conductive powder.   The electrolytic cell according to claim 1, wherein the electrode is formed in a mesh shape or a comb shape.   The said electrode is formed by apply | coating the electrically conductive paste containing electroconductive powder to the surface of the said cation exchange membrane, and heating or pressurizing. Electrolytic tank.   A pair of electrolysis chambers opposed to each other via 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, Electrolyzed water extraction means for taking out electrolyzed water obtained by applying voltage to both electrodes and electrolyzing raw water supplied to each electrolysis chamber by the raw water supply means from each electrolysis chamber; And an electrode for generating electrolyzed water using an electrolytic cell in which the electrode is in close contact with both surfaces of the cation exchange membrane to form a membrane-electrode structure capable of transmitting a cation. A characteristic electrolyzed water generating device.

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