WO2016117170A1

WO2016117170A1 - Porous diaphragm, production method therefor, electrode unit for producing hypochlorous acid water, and hypochlorous-acid-water production device using same

Info

Publication number: WO2016117170A1
Application number: PCT/JP2015/076159
Authority: WO
Inventors: 内藤　勝之; 直美信田; 典裕吉永; 梅　武; 富松　師浩; 亮介八木; 横田　昌広; 英男太田
Original assignee: 株式会社東芝
Priority date: 2015-01-21
Filing date: 2015-09-15
Publication date: 2016-07-28
Also published as: CN107208286A; JP6542265B2; JPWO2016117170A1; CN107208286B

Abstract

Provided are: a porous diaphragm which exhibits high efficiency and a long life; a production method therefor; an electrode unit; and a hypochlorous-acid-water production device. An electrode unit according to an embodiment of the present invention is provided with: a positive electrode; a negative electrode; and a porous diaphragm which is formed at the negative-electrode side of the positive electrode, and which includes an inorganic oxide having a positive zeta potential in a pH range from 2 to 6.

Description

Porous diaphragm, method for producing the same, electrode unit for producing hypochlorous acid water, and apparatus for producing hypochlorous acid water using the same

An embodiment of the present invention relates to a porous diaphragm, a method for producing the same, an electrode unit for producing hypochlorous acid water, and an apparatus for producing hypochlorous acid water using the same.

BACKGROUND ART In recent years, an electrolysis apparatus has been provided that electrolyzes water or a salt to generate electrolytic water having various functions, such as alkaline ionized water, ozone water or hypochlorous acid water. Among these, hypochlorous acid water is highly bactericidal but stable, and unlike hypochlorite, there is no residue, so it is expected to be widely applied to the fields of food, hygiene, agriculture and the like. The hypochlorous acid water producing apparatus mainly includes an electrolytic cell and an electrode unit provided in the electrolytic cell.

For example, a hypochlorous acid water producing apparatus having a three-chamber electrolytic cell has been proposed. The electrolytic cell is divided into three compartments of an intermediate compartment and an anode compartment and a cathode compartment located on both sides of the intermediate compartment by a cation exchange membrane and an anion exchange membrane constituting an electrode unit. The anode chamber and the cathode chamber are provided with the anode and the cathode of the electrode unit, respectively. As an electrode, the electrode of the porous structure which processed many through-holes in the metal plate base material by expansion, etching, or punching is used.

In such a hypochlorous acid water producing apparatus, for example, salt water is poured into the intermediate chamber, and water is circulated through the anode chamber and the cathode chamber. The salt water in the middle chamber is electrolyzed at the cathode and the anode, whereby hypochlorous acid water is produced at the anode, and sodium hydroxide water and hydrogen are produced at the cathode chamber. The generated hypochlorous acid water is used as a sterilizing water, and the sodium hydroxide water is used as a washing water.

In the three-chamber type hypochlorous acid water producing apparatus, the anion exchange membrane is easily chemically degraded by chlorine and hypochlorous acid. Therefore, a technology has been proposed in which a non-woven fabric having an overlap or a cut is inserted between the electrode and the electrolyte membrane to reduce the deterioration of the electrode due to chlorine.

In addition, an electrode unit for water electrolysis is known in which a porous inorganic oxide film is formed of sol and gel on a flat electrode to make it difficult to pass chlorine ions to prevent the reaction of chlorine ions and to easily pass only water. ing.

However, in the apparatus for producing hypochlorous acid water having the above-described configuration, deterioration of the electrode unit is inevitable due to long-term operation.

JP 2012-172199 A Japanese Patent Application Laid-Open No. 2006-322053 Japanese Patent Application Laid-Open No. 11-100688 JP 2014-12889 A

An object of the embodiment of the present invention is to provide a long-life porous diaphragm, a method for producing the same, an electrode unit for producing hypochlorous acid, and an apparatus for producing hypochlorous acid using the same.

The electrode unit for producing hypochlorous acid water according to the embodiment has a positive electrode, a negative electrode disposed opposite to the positive electrode, and a positive zeta potential in a range of pH 2 to 6 And a first porous diaphragm containing a first inorganic oxide.

It is a figure showing roughly an example of the hypochlorous acid water manufacture device concerning an embodiment. It is a disassembled perspective view of the electrode unit of the hypochlorous acid water manufacturing apparatus which can be used for embodiment. It is a schematic diagram which shows the ion transport of the porous diaphragm containing the inorganic oxide which concerns on embodiment. It is a graph showing the relationship between the zeta-potential of titanium oxide, and pH. It is a graph showing the relationship between the zeta-potential of zirconium oxide, and pH. It is a schematic diagram showing an example of the structure of the electrode used for embodiment, and a porous diaphragm. It is a schematic diagram showing an example of the 1st electrode and porous diaphragm manufacturing process used for an embodiment. It is a schematic diagram showing an example of the 1st electrode and porous diaphragm manufacturing process used for an embodiment. It is a schematic diagram showing an example of the 1st electrode and porous diaphragm manufacturing process used for an embodiment. It is a schematic diagram showing an example of the 1st electrode and porous diaphragm manufacturing process used for an embodiment. It is a schematic diagram showing an example of the 1st electrode and porous diaphragm manufacturing process used for an embodiment. It is a schematic diagram showing an example of the 1st electrode and porous diaphragm manufacturing process used for an embodiment. It is a figure showing an example of the section of the porous diaphragm concerning an embodiment. It is a figure showing an example of an electrode which has a diamond-shaped through-hole with a round corner concerning an embodiment. It is a figure showing an example of an electrode which has a diamond-shaped through-hole with a round corner concerning an embodiment. It is a figure showing roughly another example of the electrolysis device concerning an embodiment. It is a figure showing an example of the manufacturing method of the porous diaphragm used for embodiment. It is a figure showing an example of the manufacturing method of the porous diaphragm used for embodiment. It is a figure showing an example of the manufacturing method of the porous diaphragm used for embodiment. It is a figure showing an example of the manufacturing method of the electrode used for an embodiment. It is a figure showing an example of the manufacturing method of the electrode used for an embodiment. It is a figure showing an example of the manufacturing method of the electrode used for an embodiment. It is a figure showing an example of the manufacturing method of the electrode used for an embodiment. It is a figure showing roughly an example of an electrode device concerning an embodiment.

An electrode unit for producing hypochlorous acid water according to an embodiment includes a positive electrode, a negative electrode disposed opposite to the positive electrode, and a first porous diaphragm formed on the negative electrode side of the positive electrode. Including.

The first porous diaphragm contains a first inorganic oxide having a positive zeta potential in the pH range of 2 to 6.

In addition, the electrode unit for producing hypochlorous acid water according to the embodiment can further include a second porous diaphragm formed on the positive electrode side of the negative electrode.

The second porous diaphragm can contain a second inorganic oxide having a negative zeta potential in the pH range of 8 to 10.

As the first inorganic oxide, at least one selected from zirconium oxide, titanium oxide, zircon and aluminum oxide can be used.

As the second inorganic oxide, at least one selected from zirconium oxide, titanium oxide, aluminum oxide, silicon oxide, tungsten oxide, zeolite, zircon and zeolite can be used.

The first inorganic oxide can be distributed at a higher density on the surface of the first porous membrane than inside the first porous membrane.

The second inorganic oxide can also be distributed at a higher density on the surface of the second porous membrane than inside the second porous membrane.

As an example of a positive electrode which can be used in the embodiment, it has a first surface and a second surface opposite to the first surface, and a plurality of first holes are opened in the first surface; A plurality of second holes having a diameter larger than that of the first holes are opened on the surface, and a plurality of first holes communicate with one second hole.

As a first porous diaphragm, a first porous layer having a first pore size, and a second porous layer formed on the first porous layer and having a second pore size different from the first pore size A multilayer film can be used that includes the texture layer.

Also, as a second porous diaphragm, a third porous layer having a third pore size, and a fourth porous layer formed on the third porous layer and having a fourth pore size different from the third pore size And a porous layer comprising the following.

The first porous diaphragm can further include a third inorganic oxide different from the first inorganic oxide. In addition, the ratio of the first inorganic oxide to the third inorganic oxide can be different between the surface and the inside of the first porous membrane.

The third inorganic oxide can be selected from zirconium oxide, titanium oxide, zircon and aluminum oxide.

In addition, the second porous diaphragm can further include a fourth inorganic oxide different from the second inorganic oxide. In addition, the ratio of the second inorganic oxide to the fourth inorganic oxide can be different on the surface and the inside of the first porous membrane.

The fourth inorganic oxide can be selected from zirconium oxide, titanium oxide, aluminum oxide, silicon oxide, tungsten oxide, zeolite, zircon and zeolite.

Between the positive electrode and the negative electrode, means may be further provided to hold the liquid or solid electrolyte.

The surface zeta potential of the first porous diaphragm can be greater than -30 mV at pH 4.

It may further include a first catalyst layer consisting of an electrocatalyst between the positive electrode and the first porous diaphragm. In addition, a second catalyst layer can be further included on the surface of the positive electrode opposite to the first catalyst layer. It is also possible that the amount per unit area of the first catalyst layer and the amount per unit area of the second catalyst layer are different.

The apparatus for producing hypochlorous acid water according to the embodiment includes the electrode unit for producing hypochlorous acid water, a power supply for applying a voltage to the electrode, and a control device.

The porous diaphragm according to the embodiment can be used for at least one of the first porous thin film and the second porous thin film, and is a porous polytetrafluoroethylene membrane, a porous polyvinylidene fluoride membrane, And a porous laminate including at least one porous membrane of porous polyethylene membranes, and a porous composite membrane containing glass fibers and a fluorine-based polymer, formed on the porous membrane.
A covering layer formed on at least one surface of the porous laminate, comprising at least one inorganic oxide selected from the group consisting of titanium oxide, silicon oxide, aluminum oxide, zirconium oxide, tungsten oxide, and zircon including.

The porous membrane can have a water permeability of 0.1 mL / min / cm ² / MPa to 6 mL / min / cm ² / MPa.

Glass cloth can be used as glass fiber.

The porous membrane can include at least one particle selected from the group consisting of titanium oxide, silicon oxide, aluminum oxide, zirconium oxide, tungsten oxide, zeolite, and zircon.

In the method of manufacturing a porous membrane according to the embodiment, glass fibers are laminated on at least one of the porous polytetrafluoroethylene membrane, the porous polyvinylidene fluoride membrane, and the porous polyethylene membrane. And a step of applying a fluorine-containing polymer-containing liquid onto the porous membrane through the glass fibers to form a composite membrane comprising the glass fibers and the fluorine-based polymer on the porous membrane, the porous membrane and the composite membrane Applying an inorganic oxide precursor solution to at least one surface of the laminate to form a coating layer containing the inorganic oxide.

A heating press can be used as a process of laminating.

In the step of applying the inorganic oxide precursor solution to form the coating layer containing the inorganic oxide, the inorganic oxide precursor solution can be applied and then heated.

Hereinafter, various embodiments will be described with reference to the drawings. In addition, the same code | symbol shall be attached | subjected to a common structure through embodiment, and the overlapping description is abbreviate | omitted. In addition, each drawing is a schematic view for promoting the embodiment and the understanding thereof, and there are places where the shape, size, ratio, etc. are different from those of the actual device, but referring to the following description and known techniques. The design can be changed as appropriate. For example, although the electrodes are drawn on a plane in the drawing, they may be curved according to the shape of the electrode unit, or may be cylindrical.

FIG. 1: is a figure which shows roughly an example of the hypochlorous acid water manufacturing apparatus which concerns on embodiment.

The hypochlorous acid production apparatus 10 includes a three-chamber electrolytic cell 11 and an electrode unit 12. The electrolytic cell 11 is formed in a flat rectangular box shape, and the inside thereof is divided by the partition wall 14 and the electrode unit 12 into three, an anode chamber 16, a cathode chamber 18, and an intermediate chamber 19 formed between the electrodes. It is done.

The electrode unit 12 has a first electrode (anode) 20 located in the anode chamber 16, a second electrode (counter electrode, cathode) 22 located in the cathode chamber 18, and a first surface 21 a of the first electrode 20. The catalyst layer 28 may be formed on the It has a porous diaphragm 24 containing an inorganic oxide having a positive zeta potential in the pH range of 2 to 6 formed thereon. In the pH range of 8 to 10 formed on the first surface 23 a of the second electrode 22, the porous diaphragm 27 containing an inorganic oxide having a negative zeta potential may be provided. The first electrode 20 and the second electrode 22 face each other in parallel with a gap, and form an intermediate chamber (electrolyte chamber) 19 for holding an electrolyte between the

porous diaphragms

24 and 27. It is also good. In the intermediate chamber 19, a holder 25 for holding the electrolytic solution may be provided. The first electrode 20 and the second electrode 22 may be connected to each other by a plurality of insulating bridges 60.

The hypochlorous acid water producing apparatus 10 includes a power source 30 for applying a voltage to the first and

second electrodes

20 and 22 of the electrode unit 12 and a control device 36 for controlling the same. An ammeter 32 and a voltmeter 34 may be provided. The anode chamber 16 and the cathode chamber 18 may be provided with a liquid flow path. The anode chamber 16 and the cathode chamber 18 may be connected with piping, a pump or the like for supplying and discharging a liquid from the outside. Also, in some cases, a porous spacer may be provided between the electrode unit 12 and the anode chamber 16 or the cathode chamber 18.

In the electrode unit 12, the first electrode 20 and the second electrode 22 are configured in a porous structure. The first electrode 20 of the electrode unit 12 has a porous structure, and the through holes may have different opening diameters on the first surface 21 a side and the second surface 21 b side.

As shown in FIG. 1, the 1st electrode 20 has the porous structure which formed many through-holes in the base material 21 which consists of a rectangular-shaped metal plate, for example. The base 21 has a first surface 21 a and a second surface 21 b opposed substantially parallel to the first surface 21 a. The distance between the first surface 21a and the second surface 21b, that is, the plate thickness is T1. The first surface 21 a faces the porous diaphragm 24, and the second surface 21 b faces the anode chamber 16.

A plurality of first holes 40 are formed in the first surface 21 a of the base 21 and open in the first surface 21 a. In addition, a plurality of second holes 42 are formed in the second surface 21 b and open in the second surface 21 b. The opening diameter R1 of the first recess 40 on the porous diaphragm 24 side is smaller than the opening diameter R2 of the second recess 42. It is preferable that the number of the concave portions is larger in the first concave portion 40 than in the second concave portion 42. The stress due to the end of the recess to the porous diaphragm is relieved and the life of the porous diaphragm is increased. In addition, since the number of second recesses can be reduced, the electrical resistance can be reduced, which is advantageous for replacing the wiring and for mechanical retention.

The depth of the first hole 40 is T2, the depth of the second hole 42 is T3, and T2 + T3 = T1. In the embodiment, T2 <T3.

The first holes 40 are formed, for example, in a rectangular shape, and provided in a matrix on the first surface 21 a. The peripheral wall defining each first hole 40 may be formed by a tapered surface or a curved surface whose diameter is increased from the bottom of the hole toward the opening, that is, toward the first surface 21a. Good.

Although the through-hole which the 1st recessed part 40 and the 2nd recessed part 42 connected is formed in the figure, the recessed part which is not connected and the recessed part in which one part was connected may exist. The substrate 21 is the same substrate, and is not an electrode in which different substrates are partially laminated by welding or the like. When different substrates are laminated, hypochlorous acid is easily retained at the substrate contact surface, and the generation efficiency is reduced. In addition, current concentration tends to occur at the junction, and catalyst deterioration is likely to occur.

FIG. 2 is an exploded perspective view of an electrode unit for producing hypochlorous acid water that can be used in the embodiment.

In the embodiment, as shown in FIG. 2, a plurality of, for example, nine first hole portions 40 are provided to face one second hole portion 42. Each of the nine first holes 40 communicates with the second hole 42 and together with the second hole 42 form a through hole that penetrates the base 21. The interval W1 between the adjacent first holes 40 is set smaller than the interval W2 between the second holes 42. Thereby, the number density of the 1st hole 40 in the 1st surface 21a is sufficiently larger than the number density of the 2nd hole 42 in the 2nd surface 21b.

The first hole 40 is not limited to a rectangular shape, and may have another shape. The first holes 40 may be formed not only regularly but also randomly. Furthermore, not only the configuration in which all the first hole portions 40 communicate with the second hole portion 42, but also the first hole portion not communicating with the second hole portion 42 may be included.

The smaller opening of the first hole 40 is preferable to equalize the pressure, but it is necessary to have a certain size to inhibit substance diffusion, and one side of the opening is 0.1 mm in the case of a square Is preferably 2 mm, more preferably 0.2 mm to 1.5 mm, and still more preferably 0.3 mm to 1 mm. The opening square, rectangular, rhombic, circular, may be used an elliptical or the like and the various shapes, the same as the opening area of the square, those from 0.01 mm ² to 4 mm ² preferably as the opening area. The ratio (opening ratio) of the opening area to the electrode area including the opening is preferably 0.05 to 0.5, more preferably 0.1 to 0.4, and still more preferably 0.15 to 0.3. If the aperture ratio is too small, outgassing becomes difficult. When the aperture ratio is too large, the electrode reaction is inhibited.

The second holes 42 are formed, for example, in a rectangular shape, and are provided in a matrix on the second surface 21 b. The peripheral wall defining each second hole 42 is formed by a tapered surface 42a or a curved surface whose diameter is increased from the bottom of the hole toward the opening, that is, toward the second surface side. It is also good. The distance between the adjacent second holes 42, that is, the width of the linear portion of the electrode is set to W2. The second hole 42 is not limited to the rectangular shape, and may have other various shapes. Further, the second holes 42 may be formed not only regularly but also at random.

The opening of the second hole portion 42 can also have various shapes such as a square, a rectangle, a rhombus, a circle, an ellipse, and the like. A larger opening is preferable for improving the degassing, but the opening of the second hole 42 can not be made so large because the electrical resistance is increased. In the case of a square opening, one side is preferably 1 mm to 40 mm, more preferably 2 mm to 30 mm, and still more preferably 3 mm to 20 mm. Although various shapes such as a square, a rectangle, a rhombus, a circle, an ellipse, etc. can be used as the opening, the opening area is preferably 1 to ²⁰⁰ mm ² , which is the same as the opening area of the square. It is possible to have an opening that is elongated in one direction such as a rectangle or an ellipse and connected to the end of the electrode.

The porous diaphragm 24 is formed, for example, in a rectangular shape having substantially the same size as the first electrode 20, and is opposed to the entire surface of the first surface 21a. The porous diaphragm 27 is formed in a rectangular shape substantially equal in size to the second electrode 22, and is opposed to the entire surface of the first surface 23a. The

porous membranes

24 and 27 may be a laminated membrane of a plurality of porous membranes having different pore sizes.

As the base 21 of the first electrode 20, a valve metal such as titanium, chromium, aluminum or an alloy thereof, or a conductive metal can be used. Among these, titanium is preferred. An electrocatalyst (catalyst layer) 28 is formed on the first surface 21 a and the second surface 21 b of the first electrode 20. As the anode catalyst, it is preferable to use a noble metal catalyst such as platinum or an oxide catalyst such as iridium oxide. The amount per unit area of the electrocatalyst may be formed to be different on both sides of the first electrode. This can suppress side reactions and the like. The surface roughness of the substrate 21 is preferably 0.01 μm to 3 μm. Below 0.01 μm, the surface area of the substance of the electrode decreases. When it is 3 μm or more, stress on the porous diaphragm tends to be concentrated on the convex portion of the electrode. More preferably, it is 0.02 μm to 2 μm, and still more preferably 0.03 μm to 1 μm. The flatness of the electrode is important for chemically stable but fragile porous membranes containing inorganic oxides.

FIG. 3 schematically shows ion transport in a porous diaphragm that can be used in the embodiment.

The porous diaphragm 24 contains an inorganic oxide having a positive zeta potential in the pH range of 2 to 6. Since hypochlorous acid having a pH of 2 to 6 is highly bactericidal, the electrolysis conditions are preferably adjusted so that the anode water falls within this pH range. More preferably, the pH is from 3 to 6, and even more preferably, the pH is from 4 to 6. As schematically shows an example of the titanium oxide in FIG. 3, the positive electrode near the pH region, chloride ion (Cl ^-) transport performance is increased inside the porous membrane against, hypochlorous acid (HClO ) Is sent through the anode 20 to the anode chamber. Conversely, sodium ions are less likely to enter the inside of the porous diaphragm. For this reason, according to the embodiment, by using a porous membrane containing an inorganic oxide having a positive zeta potential in the pH range of 2 to 6, even without using an ion exchange membrane, Chloride ions can be selectively permeated into the anode compartment.

If the pH is less than 2, chlorine gas is likely to be generated and the risk increases. When the pH exceeds 6, the bactericidal properties decrease.

FIG. 4 is a graph showing the pH dependency of the zeta potential of titanium oxide, and FIG. 5 is a graph showing the pH dependency of the zeta potential of zirconium oxide.

As shown, titanium oxide and zirconium oxide are positive in the acidic region and negative in the alkaline region.

Various inorganic oxides having a positive zeta potential in the pH range of 2 to 6 can be used. For example, zirconium oxide, titanium oxide, aluminum oxide, tin oxide, copper oxide, iron oxide, and zircon (composite oxide of zirconium and silicon) can be used. Among these, zirconium oxide, titanium oxide and zircon are preferable from the viewpoint of chemical stability. Zirconium oxide is more preferable because of its high bending resistance.

The inorganic oxide may contain a hydroxide, an alkoxide, an oxyhalide or a hydrate. When the inorganic oxide is produced through hydrolysis of metal halides or metal alkoxides, it tends to be a mixture of these although it depends on the temperature of post-treatment.

The inorganic oxide may not have uniform distribution in the porous membrane. For example, many inorganic oxides can exist around and on the surface of the pores. For example, the area coverage of the inorganic oxide on the surface may be 50 to 100%, and the ratio of the inorganic oxide on the cross section inside the porous membrane may be 20 to 80% less than the surface. A mixture of different metal oxides can be used as the inorganic oxide. Also, the location may be different. For example, it is possible that a layer containing zirconium oxide having a large bending strength is present on the surface, and a layer containing titanium oxide having a large absolute value of positive potential is present inside.

The zeta potential of the surface of the porous membrane is preferably greater than -30 mV at pH 4. The value of pH 4 is important because the value is greater than -30 mV at pH 2. If the voltage is less than -30 mV, chloride ions are less likely to enter the inside of the porous diaphragm even if a voltage is applied to the porous diaphragm. If too high a voltage is applied, side reactions are likely to occur in the electrolytic reaction. More preferably, it is larger than -15 mV, and more preferably positive.

In an embodiment, it is possible to further arrange another porous diaphragm on the positive electrode side on the negative electrode, and this porous diaphragm has an inorganic oxidation with negative zeta potential in the pH range of 8 to 10 Can be contained. As a result, the transport performance of cations such as sodium ions and protons in the porous diaphragm is increased in the vicinity of the cathode in the weak alkaline region, and cations such as sodium ions and protons can be transferred to the cathode chamber without using ion exchange membranes. It can be selectively transmitted.

Zirconium oxide, titanium oxide, aluminum oxide, silicon oxide, tungsten oxide, zircon, and zeolite can be used as the inorganic oxide having a negative zeta potential in the pH range of 8 to 10. As the inorganic oxide, mixtures of different metal oxides can be used. Also, the location may be different. For example, a layer containing zirconium oxide having a large bending strength can be present on the surface, and a layer containing silicon oxide or tungsten oxide having a wide negative pH range can be present inside.

The inorganic oxide porous diaphragm 24 can have irregular pores also in the plane and sterically, by applying nanoparticles to form a film, or by using sol-gel. In this case, the porous diaphragm 24 is resistant to bending and the like. The porous diaphragm 24 may contain a polymer in addition to the inorganic oxide. The polymer gives the membrane flexibility. As such a polymer, one having a chemically stable main chain substituted with a halogen atom is preferable, and polyvinylidene chloride, polyvinylidene fluoride, Teflon (registered trademark) and the like are preferable. In addition, as polymers, hydrocarbon polymers such as polyethylene and polypropylene, so-called engineering plastics such as polyimide, polysulfone and polyphenylene sulfide can be used.

The pore diameter of the porous diaphragm 24 may be different from the aperture diameter on the first electrode 20 side and the aperture diameter on the second electrode 22 side. By making the opening diameter on the side of the second electrode 22 of the hole larger, movement of ions can be facilitated, and stress concentration by the through hole 13 of the first electrode 20 can be reduced. This is because the larger the opening on the electrode 22 side, the easier the movement of ions by diffusion. Anions are relatively easily attracted to the electrode even if the pore size on the electrode 20 side is small. Conversely, if the pore size on the electrode 20 side is large, the generated hypochlorous acid and the like will easily diffuse to the porous diaphragm side.

The pore size on the surface of the porous membrane can be measured by using a high resolution scanning electron microscope (SEM). Also, the internal pores can be measured by cross-sectional SEM observation.

The schematic diagram showing an example of a structure of the electrode and porous diaphragm which are used for FIG. 6 at embodiment is shown.

As shown in FIG. 6, the porous diaphragm 24 has a first region 24 a covering a portion of the first surface 21 a of the first electrode 20 and a second region 24 b covering the opening of the through hole 40. In the part 21a, it is difficult to discharge the gas such as chlorine generated. Therefore, the electrode unit 12 is easily deteriorated. Therefore, in the porous diaphragm 24, the surface pores of the first region are eliminated, that is, they are formed non-porous, or the diameter of the surface pores in the first region 24a is smaller than the diameter of the pores in the second region. Thus, the electrolytic reaction in the area in contact with the first area 24 a can be suppressed, and the deterioration of the electrode unit 12 can be prevented. In order to form non-porous or to reduce the diameter of the pore, a thin non-porous film or a porous diaphragm with a small pore diameter can be separately formed on the first surface 21a of the first electrode by screen printing or the like. However, since the reaction area of the electrode is reduced, it is possible to cause a sufficient reaction to occur in the electrode region in the part where gas is easily released. Also. By covering the second surface 21b opposite to the porous diaphragm 24 of the first electrode 20 with an electrically insulating film, it is possible to reduce side reactions.

As the porous diaphragm 24, a multilayer film in which a plurality of porous diaphragms having different pore sizes are stacked may be used. In this case, by making the pore diameter of the porous diaphragm located on the side of the second electrode 22 larger than the pore diameter of the porous diaphragm located on the side of the first electrode 20, the movement of ions is made easier and the penetration of the electrode Stress concentration due to holes can be reduced.

With the porous diaphragm 24 sandwiched between the first electrode 20 and the second electrode 22 configured as described above, by pressing them, the first electrode 20, the porous diaphragm 24, the second electrode An electrode unit 12 is obtained in contact with 22.

As shown in FIG. 1, the electrode unit 12 is disposed in the electrolytic cell 11 and attached to the partition wall 14. The partition 14 and the electrode unit 12 divide the inside of the electrolytic cell 11 into an anode chamber 16 and a cathode chamber 18. Thereby, the electrode unit 12 is arrange | positioned in the electrolytic vessel 11 so that the arrangement direction of a structural member may become horizontal direction, for example. The first electrode 20 of the electrode unit 12 is disposed facing the anode chamber 16, and the second electrode 22 is disposed facing the cathode chamber 18.

In the electrolytic device 10, both electrodes of the power source 30 are electrically connected to the first electrode 20 and the second electrode 22. The power supply 30 applies a voltage to the first and

second electrodes

20, 22 under the control of the controller 36. The voltmeter 34 is electrically connected to the first electrode 20 and the second electrode 22 and detects a voltage applied to the electrode unit 12. The detected information is supplied to the control device 36. The ammeter 32 is connected to the voltage application circuit of the electrode unit 12 and detects the current flowing through the electrode unit 12. The detected information is supplied to the control device 36. The control device 36 controls the application or load of the voltage to the electrode unit 12 by the power supply 30 according to the detection information in accordance with the program stored in the memory. The electrolytic device 10 applies or applies a voltage between the first electrode 20 and the second electrode 22 in a state in which the reaction target material is supplied to the anode chamber 16 and the cathode chamber 18, and performs electrochemistry for electrolysis. Let the reaction proceed.

According to the electrolytic device and the electrode unit configured as described above, the first electrode 20 can be provided by providing the porous diaphragm 24 containing a chemically stable inorganic oxide that has high selective transport efficiency of ions. The distance between the second electrode 22 and the second electrode 22 can be kept as constant as possible, and the flow of liquid can be made uniform. This enables the electrolytic reaction to occur uniformly at the electrode interface. Since the electrolytic reaction occurs uniformly, degradation of the catalyst and degradation of the electrode metal occur uniformly, and the life of the electrode unit can be extended. Further, the electrolytic reaction can be uniformly generated uniformly, and the reaction efficiency of the electrolytic device can be improved and the deterioration of the electrode can be prevented.

In the first electrode 20 of the porous structure, by forming the through hole with a tapered surface or a curved surface where the opening on the first surface side is wide, the contact angle with the opening of the through hole with the porous diaphragm 24 becomes an obtuse angle Stress concentration on the porous diaphragm 24 can also be reduced.

FIGS. 7A to 7F respectively show schematic views showing an example of a manufacturing process of the first electrode and the porous thin film used in the embodiment.

The first electrode 20 and the porous membrane 24 can be manufactured as follows.

The first electrode 20 can be manufactured, for example, by an etching method using a mask. As shown in FIGS. 7A and 7B, one flat base material 21 is prepared, and resist

films

50a and 50b are applied to the first surface 21a and the second surface 21b of the base material 21, respectively. As shown in FIG. 7C, the resist

films

50a and 50b are exposed using an optical mask (not shown), and

etching masks

52a and 52b are produced. As shown in FIG. 7D, by wet etching the first surface 21a and the second surface 21b of the base material 21 with a solution through the

masks

52a and 52b, a plurality of first holes 40 and a plurality of second holes are obtained. The holes 42 are formed. Thereafter, the

masks

52a and 52b are removed to obtain the first electrode 20.

The shapes of the tapers and the curved surfaces of the first and

second holes

40 and 42 can be controlled by the material of the base 21 and the etching conditions. A reverse tapered shape is also possible depending on the conditions of etching. The depth of the first hole 40 is T2, and the depth of the second hole 42 is T3, and the first and second holes are formed such that T2 <T3. In the etching, both sides of the substrate 21 may be etched simultaneously, or one side may be etched. The type of etching is not limited to wet etching, and dry etching or the like may be used. Moreover, it is also possible to manufacture the 1st electrode 20 by the process by not only an etching but the expand method, the punching method, or a laser, precision cutting, etc. FIG.

As an example of forming the porous diaphragm 24 on the first surface 21a having the catalyst 28 formed on the surface of the first electrode 20, first, as shown in FIG. 7E, inorganic oxide particles and / or inorganic oxide precursor A body-containing solution is applied to the first surface 21a to form a pretreatment film 24c. Next, as shown in FIG. 7F, the pretreatment film 24c is sintered to produce a porous diaphragm 24 having pores.

As a method of preparing a solution containing an inorganic oxide precursor, for example, when a metal alkoxide is dissolved in alcohol and a high boiling point solvent such as glycerin is added or sintered to prepare a porous structure, or A solution can be prepared by mixing organic substances such as fatty acids which are easily oxidized to carbon dioxide gas. The solution can also cover the porosity of the electrode by adding a small amount of water to partially hydrolyze the metal alkoxide and raise its viscosity.

In order to form the porous diaphragm 24, a solution containing inorganic oxide particles and / or an inorganic oxide precursor can be applied to another porous film. Alternatively, a porous film having large pores may be formed in advance on the first surface 21a of the first electrode 20, and the surface and the pores may be covered with the inorganic oxide particles and / or the inorganic oxide precursor. Furthermore, a porous diaphragm having an inorganic oxide can be formed on the carrier 25 holding the electrolytic solution by the above method. Moreover, these can be combined.

As a method of applying the solution containing the inorganic oxide particles and / or the inorganic oxide precursor, brushing, spraying, dipping or the like can be used. In the step of sintering the pretreatment film 24c to make pores, the sintering temperature can be about 100 to 600.degree.

According to the above configuration and manufacturing method, it is possible to provide a long-life electrode unit capable of maintaining highly efficient hypochlorous acid manufacturing performance over a long period of time and a hypochlorous acid manufacturing apparatus using the same.

The first electrode and the second electrode are not limited to the rectangular shape, and other various shapes can be selected. The first hole and the second hole of the first electrode are not limited to the rectangular shape, and may have other various shapes such as a circle, an ellipse, and the like. The material of each component is not limited to the embodiment and the example described above, and other materials can be appropriately selected.

FIG. 8 is a schematic view showing a cross section showing the configuration of the porous diaphragm according to the embodiment.

As shown, the porous diaphragm 24 comprises at least one porous membrane 51 selected from a porous polytetrafluoroethylene membrane, a porous polyvinylidene fluoride membrane, and a porous polyethylene membrane, a glass fiber 54 and a fluorine-based membrane. A laminate with a porous composite film 52 made of a polymer (for example, polytetrafluoroethylene or polyvinylidene fluoride) 55, wherein the surface of the laminate is at least titanium oxide, silicon oxide, aluminum oxide, zirconium oxide, tungsten oxide, And zircon inorganic oxide 53.

The porous diaphragm 24 is formed, for example, in a rectangular shape having substantially the same size as the first electrode 20, and is opposed to the entire surface of the first surface 21a. The porous diaphragm 27 is formed in a rectangular shape substantially equal in size to the second electrode 22, and is opposed to the entire surface of the first surface 23a.

At least one porous membrane 51 selected from porous polytetrafluoroethylene membrane, porous polyvinylidene fluoride membrane, and porous polyethylene membrane can be used as a base membrane. In these, a porous structure is produced by drawing or the like, but in general, the control of the pore size tends to be difficult. In addition, since the mechanical strength is weak, there is a tendency for the pore diameter to change due to water pressure or the like. Glass fiber is chemically stable, and its strength is high, so there is little change in water pressure and the like. The pore size can be adjusted and the chemical and mechanical strength can be obtained by mixing this with a fluorine-based polymer to form a composite membrane. Among the above, lamination of a porous polytetrafluoroethylene membrane and a polyvinylidene fluoride composite membrane is most preferable.

When the porous thin film according to the embodiment is used, chemically stable glass fibers are mixed with a fluorine-based polymer to form a composite film, and a porous polytetrafluoroethylene film, a porous polyvinylidene fluoride film, and a porous polyethylene By laminating with a porous membrane selected from membranes, it is possible to adjust the pore diameter, to be resistant to oxidation, to have chemical strength and mechanical strength, and to provide a long-life porous diaphragm, its production method, hypochlorous acid production An electrode unit and a hypochlorous acid production apparatus using the same are obtained.

The water permeability of the porous membrane is preferably 0.1 mL / min / cm ² / MPa or more and 6 mL / min / cm ² / MPa or less. When it is smaller than 0.1 mL / min / cm ² / MPa, the ion transmission amount also becomes small and the driving voltage becomes large. When it is larger than 6 mL / min / cm 2 / MPa, the concentration of the salt in the electrolytic water becomes too high. More preferably, it is 0.3 mL / min / cm ² / MPa or more and 4 mL / min / cm ² / MPa or less, more preferably 0.5 mL / min / cm ² / MPa or more 2 mL / min / cm _{It is 2} / MPa or less.

As the porous membrane, a membrane having ion selectivity can be used. The porous membrane can be contained internally in addition to being coated with the inorganic oxide. In particular, inorganic oxides having a positive zeta potential can be used in the pH range of 2 to 6 for the porous membrane on the positive electrode side. This can increase the transport performance of the porous membrane to anions in the chemically stable weakly acidic region.

As the inorganic oxide, for example, zirconium oxide, titanium oxide, aluminum oxide, tin oxide, zircon, copper oxide, iron oxide and mixed oxides thereof can be used. Preferably, zirconium oxide, titanium oxide or zircon can be used as the inorganic oxide having good chemical stability. Among these, zirconium oxide is more preferable as an inorganic oxide having good bending resistance. Inorganic oxides can include hydroxides, alkoxides, oxyhalides, and hydrates. When inorganic oxides are produced through hydrolysis of metal halides and metal alkoxides, they may become a mixture depending on the temperature of post-treatment.

It is possible for the abundance ratio of the inorganic oxide in the porous membrane to be different depending on the place. For example, the abundance ratio of the inorganic oxide can be increased around and on the surface of the hole.

As the inorganic oxide, a composite oxide such as zircon or a mixture of different inorganic oxides can be used. In addition, the porous membrane may further contain two or more different oxides, and the abundance ratio of each oxide may be different depending on the position of the porous membrane. For example, there may be a region containing zirconium oxide with high bending strength on the surface, and an region containing titanium oxide with a large absolute value of positive potential may exist inside.

FIGS. 9A and 9B are schematic views showing an example of an electrode that can be used as the first electrode 20 of FIG.

FIG. 9A is a view of the first electrode 20 as viewed from the second surface 21 b.

FIG. 9B is a schematic view showing a cross section of the through hole.

In the drawing, the through hole is one in which the first recess 40 and the second recess 42 are connected.

The predetermined plurality of through holes provided in the first electrode 20 are, for example, diamonds with rounded corners as shown in FIG. 9B. The aperture can be measured using an optical microscope. In this case, the shape of the first recess 40 is also a rhombus with rounded corners, like the through holes. The recess cross section can be tapered or curved so that the inside becomes narrow.

Elementary reaction at the anode of hypochlorous acid is generated, M a M as catalyst _{^{+ H 2 O → M-OH}} + H + + e - ... (1)
^{M-OH → M-O +} H + + e - ... (2)
^{^{M-O + Cl - + H}} + → M + HClO ... (3)
As a total H ₂ O + Cl ⁻ → HClO + H ⁺ +2 e ⁻ (4)
It is.

On the other hand, at the cathode, 2H ₂ O + 2e ⁻ → H ₂ + 2OH ⁻ (5)
The entire reaction also contains a cation 2NaCl + 3H ₂ O → HClO + HCl + 2NaOH + H ₂ (6)
It is.

On the other hand, the anode may be side reactions in which oxygen is generated simultaneous, the reaction _{M + H 2 O → M-} OH + H + + e - ... (1)
^{M-OH → M-O +} H + + e - ... (2)
2M-O → 2M + O ₂ (7)
As a total,
_{_{2H 2 O → O 2 + 2H}} ++ 2e - ... (8)
It is.

When the concentration of chloride ion necessary for the reaction is low, the reaction of the reaction formula (7) tends to occur. Therefore, in order to produce hypochlorous acid efficiently, it is necessary to increase the concentration of chloride ions. Chloride ions are supplied from the porous diaphragm side, are accumulated at the shielding part of the electrode, and flow out from the opening to the outside by diffusion. For this reason, it is important to facilitate the migration of chloride ions in the porous diaphragm in order to increase the concentration of chloride ions.

Although any shape is possible as a shape of the through-hole of embodiment, it is a round rectangle with an end, or an ellipse or a diamond with a round corner is preferable. In such a shape, the ends are round, so stress concentration on the gap hardly occurs. In addition, if the opening interval can be made dense, the aperture ratio can be increased.

The opening area of the through hole can be 0.01 mm ² to 4 mm ² . If it is smaller than 0.01 mm ^2, it becomes difficult to discharge the reaction products such as gas and hypochlorous acid to the outside, and the members are easily deteriorated. If it is larger than 4 mm ² , the electrical resistance tends to increase and the efficiency of the electrode reaction tends to decrease. Preferably, it is 0.1 mm ² to 1.5 mm ² . More preferably, it is 0.2 mm ² to 1 mm ² .

The opening area of the second recess can be 1 to 1600 mm ² . Preferably it is 4 mm ² to 900 mm ² , more preferably 9 mm ² to 400 mm ² . It is also possible to have a recess such as a rectangle or an ellipse, which is elongated in one direction and connected to the end of the electrode excluding the seal portion.

The opening of the second recess 42 may have various shapes such as a square, a rectangle, a rhombus, a circle, and an ellipse. The larger the opening diameter of the second concave portion 42, the better the hypochlorous acid and outgassing can be made, but it can not be made so large because the electrical resistance is increased. As the opening of the second recess 62, as shown, it is possible to have a recess such as a rectangle or an ellipse, which is elongated in one direction and connected from end to end of the electrode excluding the sealing portion.

In addition, the opening of the first recess 63 can also be in various shapes such as a square, a rectangle, a rhombus, a circle, and an ellipse. As shown, it is possible to have an opening that is long in one direction such as a rectangle or an ellipse and connected to the end of the electrode excluding the seal portion.

The two recesses may be orthogonal or parallel to one end of the first recess and the other end of the second recess. It is easy to diffuse gas if it is orthogonal. If it is parallel, it is easy to collect chloride ions. Orthogonal means crossing at an angle of 87 degrees to 93 degrees, and parallel means a crossing angle of 3 degrees or less.

In the first electrode 20 of the porous structure, the through hole is formed by a tapered surface or a curved surface where the opening on the first surface side is wide, whereby the contact angle with the opening of the through hole with the porous diaphragm 24 becomes an obtuse angle. The stress concentration on the diaphragm 24 can also be reduced.

FIG. 10 is a view schematically showing another example of the electrolytic device according to the embodiment.

As shown in FIG. 10, in addition to the configuration of FIG. 1, the anode chamber 16 and the cathode chamber 18 may be provided with a liquid flow path. Also, in some cases, a porous spacer may be provided between the electrode unit 12 and the anode chamber 16 or the cathode chamber 18. Further, a line L1 for introducing an electrolyte containing chloride ions into the electrolytic cell 11, a salt water reservoir 107, lines L2 and L3 for supplying water to the electrolytic cell, a line L4 for taking out acidic electrolytic water from the electrolytic cell, and alkaline electrolysis from the electrolytic cell You may further provide the line L5 which takes out water. In addition, a line L7 may be provided to circulate the electrolyte containing chloride ions, or a line may be provided to discharge the electrolyte. Further, the water softener 109 and a line L6 for supplying the acidic electrolyzed water for adsorbent regeneration from the acidic electrolyzed water reservoir 106 may be further provided to the water softener 109. The water softener may be used only for water supplied to the cathode side. Furthermore, a tank for storing alkaline electrolyzed water may be provided. In addition, a tank may be provided for mixing the acidic waste solution and the alkaline waste solution to approach neutral. A water quality sensor 70 may be installed in each line.

An example of a method of manufacturing the porous diaphragm 24 having the above-described structure will be described below.

FIGS. 11A to 11C are views showing an example of a method of manufacturing a porous diaphragm according to the embodiment.

At least one porous membrane 51 selected from a porous polytetrafluoroethylene membrane, a porous polyvinylidene fluoride membrane, and a porous polyethylene membrane as shown in FIG. 11A is prepared. Next, as shown in FIG. 11B, the porous film 51 and the glass fiber 54 are laminated. Then, as shown to FIG. 11C, the containing liquid of a fluorine-type polymer is apply | coated and a fluorine-type polymer coating layer is produced. Thereafter, it is dried to form a composite porous membrane 52 of glass fibers 54 and a fluorine-based polymer layer 55. Next, an inorganic oxide precursor solution is applied to the surface of the composite porous membrane 52 and heated to manufacture a porous diaphragm 24 as shown in FIG.

It is preferable to apply a hot press to the lamination of at least one porous membrane 51 and glass fiber 54 selected from a porous polytetrafluoroethylene membrane, a porous polyvinylidene fluoride membrane, and a porous polyethylene membrane. In particular, it is preferable to apply a hot roller press. The temperature is preferably 100 ° C. to 130 ° C. for a porous polytetrafluoroethylene membrane or porous polyvinylidene fluoride membrane, and preferably 60 ° C. to 80 ° C. for a porous polyethylene membrane.

The step of applying the fluorine-containing polymer-containing liquid includes dip coating, spray coating, bar coating, drop coating, screen printing and the like. Dip coating is preferable from the viewpoint of mass productivity and controllability. In spray coating, bar coating, drop coating, screen printing, it is preferable to use a slightly hydrophobic polymer or glass such as PET for the substrate, and simply peel the coated and dried porous membrane precursor from the substrate. Can.

Preferably, the inorganic oxide precursor is a metal alkoxide. A porous diaphragm is manufactured by applying and heating an alcohol solution of a metal alkoxide on the porous diaphragm precursor. Examples of the step of applying an alcohol solution of metal alkoxide include dip coating, spray coating, bar coating, drop coating, screen printing and the like. Dip coating is preferable from the viewpoint of mass productivity and controllability. The heating is preferably 200 ° C. to 300 ° C. for the porous polytetrafluoroethylene membrane, 100 ° C. to 130 ° C. for the porous polyvinylidene fluoride membrane, and 80 ° C. to the porous polyethylene membrane. 100 ° C. is preferred. It is particularly preferable for the porous polyethylene film to be heated by a near infrared lamp, and only the surface temperature can be made high.

12A to 12D show a method of manufacturing the first electrode according to the embodiment.

The first electrode 20 can be manufactured, for example, by an etching method using a mask.

As shown in FIGS. 12A and 12B, one flat substrate 21 is prepared.

Resist

films

50 a and 50 b are applied to the first surface 21 a and the second surface 21 b of the base material 21.

As shown in FIG. 12C, the resist

films

50a and 50b are exposed using an optical mask (not shown), and

etching masks

52a and 52b are produced. The optical mask defines the aperture area and the aperture ratio.

As shown in FIG. 12D, the plurality of first recesses 40 and the plurality of second recesses are formed by wet etching the first surface 21a and the second surface 21b of the base material 21 with the solution through the

masks

52a and 52b. Form 42 Thereafter, the

masks

52a and 52b are removed to obtain the first electrode 20. The planar shapes of the first recess 40 and the second recess 42 can be controlled by the optical mask and the etching conditions. By designing the mask, the aperture ratio, aperture area, aperture shape and the like in the electrode can be freely controlled.

The shape of the taper and the curved surface of the first and

second recesses

40 and 42 and the sectional curvature can be controlled by the material of the base 21 and the etching conditions. When the depth of the first recess 40 is T2 and the depth of the second recess 42 is T3, the first and second recesses are formed such that T2 <T3. In the etching, both sides of the substrate 21 may be etched simultaneously, or one side may be etched. The type of etching is not limited to wet etching, and dry etching or the like may be used. Further, the first electrode 20 can be manufactured not only by etching but also by processing such as an expanding method, a punching method, or a laser or precision cutting, but a wet etching method is most preferable. Note that the radius of curvature of the edge portion of the first recess or the second recess can be adjusted to a predetermined value by wet etching after the electrode is manufactured by another method.

As the base 21 of the first electrode 20 used in the embodiment, a valve metal such as titanium, chromium, aluminum or an alloy thereof, or a conductive metal can be used. In the case of using for the anode, titanium is particularly preferred. When using for a cathode, titanium, chromium, aluminum, other alloys, stainless steel, etc. are preferable. Among them, stainless steel, such as SUS316L and SUS310S, which is less likely to cause hydrogen embrittlement is particularly preferable.

An electrocatalyst (catalyst layer) 28 is formed on the first surface 21 a and the second surface 21 b of the first electrode 20. As the anode catalyst, it is preferable to use a noble metal catalyst such as platinum or an oxide catalyst such as iridium oxide. It is preferable to produce minute oxide film asperities by anodic oxidation of the electrode before producing the anode catalyst, since the adhesion between the catalyst and the substrate is increased.

A first catalyst layer comprising an electrocatalyst provided between a first electrode and a first porous diaphragm, and a first catalyst provided on the surface of the first electrode opposite to the first catalyst layer The layer may further include a second catalyst layer having a different amount per unit area.

The amount per unit area of the electrocatalyst may be formed to be different on both sides of the first electrode. This can suppress side reactions and the like.

It is preferable that the surface (first surface) on the porous membrane side of the positive electrode is substantially flat except for the concave portion. The surface roughness of the flat portion is preferably 0.01 μm to 3 μm. If it is smaller than 0.01 μm, the surface area of the substance of the electrode tends to decrease, and if it is larger than 3 μm, stress on the porous membrane tends to be concentrated on the convex portion of the electrode. More preferably, it is 0.02 μm to 2 μm, and still more preferably 0.03 μm to 1 μm.

second electrodes

Next, various examples and comparative examples will be described.
Example 1
As the electrode base 21, a flat titanium plate having a thickness T1 of 0.5 mm is prepared.

By etching this titanium plate in the same manner as the steps shown in FIGS. 7A to 7F, an electrode 20 having the same configuration as that of FIG. 1 is produced. In the electrode 20, the thickness (the depth of the first hole) of the region including the small diameter first hole 40 is 0.15 mm, and the thickness of the region including the large diameter second hole 42 (second hole Depth) is 0.35 mm. The first hole 40 is a square, and the apex of the square is rounded, but one side R1 of the square obtained by extrapolating the straight portion is 0.57 mm, the second hole 42 is a square, and the apex of the square is rounded However, one side R2 of the square obtained by extrapolating the straight portion is 2 mm. The width W1 of the linear portion formed between the adjacent first holes 40 is 0.1 mm, and the width W2 of the wide linear portion formed between the adjacent second holes 42 is 1.0 mm.

The etched electrode substrate 21 is treated at 80 ° C. for 1 hour in a 10 wt% aqueous solution of oxalic acid. A solution prepared by adding 1-butanol to 0.25 M (Ir) to iridium chloride (IrCl ₃ · nH ₂ O) is applied to the first surface 21 a of the electrode substrate 21 with a brush and then dried, The catalyst layer 28 is formed by calcination. In this case, drying is carried out at 80 ° C. for 10 minutes, and calcination is carried out at 450 ° C. for 10 minutes. An electrode substrate obtained by repeating such application, drying, and firing five times is cut into a size of a reaction electrode area of 3 cm × 4 cm to obtain a first electrode (anode) 20. Although the density is small on the surface 21b of the electrode 20, a part of the catalyst layer is formed. This catalyst layer serves to electrolyze water molecules to lower the pH.

Ethanol and diethanolamine are added to tetraisopropoxytitanium (IV) in an ice bath, and ethanol mixed water is added dropwise with stirring to prepare a sol. In order to increase the viscosity of the sol and improve the porosity by heat treatment, polyethylene glycol (molecular weight 5000) is added to the sol returned to room temperature to obtain a porous diaphragm-coated material. The obtained porous diaphragm coating material is coated on the first surface 21 a of the first electrode 20 with a brush to form a coating film. The coated film is baked at 500 ° C. for 7 minutes. After the application and baking of the porous diaphragm coating material are repeated three times, the porous diaphragm 24 made of titanium oxide is obtained by baking at 500 ° C. for 1 hour. The zeta potential at each pH of titanium oxide is represented, for example, by the graph of FIG. The zeta potential is measured by electrophoresis (Zetasizer Nano ZS manufactured by Malvern Co., Ltd.), and pH is measured from the acidic side to the alkaline side by adding hydrochloric acid and sodium hydroxide to pure water.

In the electrode preparation, a second electrode (counter electrode, cathode) 22 is formed in the same manner as the first electrode except that platinum is sputtered instead of iridium oxide as a catalyst layer. A porous diaphragm 27 made of a titanium oxide film is fabricated thereon in the same manner as described above.

The electrode unit 12 shown in FIG. 1 is manufactured using these first electrode 20 and second electrode 22 electrodes. A porous polystyrene having a thickness of 5 mm is used as a holder 25 for holding the electrolytic solution. The first and second electrodes, the porous diaphragm, and the porous polystyrene are stacked and fixed using a silicone sealant, to form an electrode unit 12. Using this electrode unit 12, an electrolytic device 10 having the same configuration as that of FIG. 1 is produced.

The anode chamber 16 and the cathode chamber 18 of the electrolytic cell 11 are each formed of a container made of vinyl chloride in which a straight flow path is formed. The control device 36, the power supply 30, the voltmeter 34, and the ammeter 32 are installed in the electrode unit 12. Furthermore, a pipe for supplying water to the anode chamber 16 and the cathode chamber 18 and a pump are connected to the electrolytic cell 11, and saturation for circulating and supplying a saturated saline solution to the holder (porous polystyrene) 25 of the electrode unit 12. The electrolytic device 10 is obtained by connecting a saline solution tank, piping, and a pump to the electrode unit.

Using the electrolytic device 10 thus obtained, electrolysis is carried out at a voltage of 4 V and a current of 1.5 A, with hypochlorous acid water on the first electrode (anode) 20 side and sodium hydroxide on the second electrode (cathode) 22 side. Produce water. Even after 1000 hours of continuous operation, almost no increase in voltage or change in product concentration is observed, and stable electrolytic processing can be performed.

(Example 2)
An aqueous dispersion mixture of titanium oxide particles and polyvinylidene fluoride particles having a particle diameter of 100 to 500 μm is applied to a glass cloth with a thickness of 100 μm as a porous diaphragm and dried. Furthermore, it is immersed in a 5% isopropanol solution of tetraisopropoxyzirconium (IV) and pulled up to the atmosphere. Dry in air at 80 ° C. for 1 hour to make a porous diaphragm. From the observation of the cross-sectional SEM, this porous membrane has more inorganic oxide on the surface and the pore surface, and the pore diameter is smaller. The zeta potential at pH 4 of this porous diaphragm surface is -12 mV.

An electrode unit is formed in the same manner as in Example 1 except that the porous diaphragm is used instead of the porous diaphragm prepared by applying and baking the porous diaphragm coating material to the first and second electrodes, respectively. Do. Using this electrode unit, an electrolytic device having the same configuration as that shown in FIG. 1 is produced.

Using this electrolytic device, electrolysis is carried out at a voltage of 4.4 V and a current of 1.5 A, and sodium hypochlorite water on the first electrode (anode) 20 side and sodium hydroxide water on the second electrode (cathode) 22 side Generate Even after 1000 hours of continuous operation, almost no increase in voltage or change in product concentration is observed, and stable electrolytic processing can be performed.

(Example 3)
Prepare a 5 mm thick porous polystyrene. While ultrasonic dispersion is applied to an aqueous dispersion of zirconium oxide particles having a particle diameter of 100 to 500 μm in this porous polystyrene, suction filtration is alternately performed from both sides, and the zirconium oxide particles are adsorbed on the pores. FIG. 5 shows the pH dependency of zeta potential of zirconium oxide. Immerse in a 5% solution of tetraisopropoxyzirconium (IV) in isopropanol and pull up to the atmosphere. Dry in air at 80 ° C. for 1 hour to make a porous diaphragm.

Using this electrolytic device, electrolysis is carried out at a voltage of 4.2 V and a current of 1.5 A, and sodium hypochlorite water on the first electrode (anode) 20 side and sodium hydroxide water on the second electrode (cathode) 22 side Generate Even after 1000 hours of continuous operation, almost no increase in voltage or change in product concentration is observed, and stable electrolytic processing can be performed.

(Example 4)
An electrolytic device 10 is produced in the same manner as in Example 1 except that triisoproxyaluminum is used instead of tetraisopropoxytitanium (IV).

Using this electrolyzer, electrolysis is performed at a voltage of 4.0 V and a current of 1.5 A, and sodium hypochlorite water on the first electrode (anode) 20 side and sodium hydroxide water on the second electrode (cathode) 22 side Generate Even after 1000 hours of continuous operation, almost no increase in voltage or change in product concentration is observed, and stable electrolytic processing can be performed.

(Example 5)
An electrolytic device 10 is produced in the same manner as in Example 3 except that zircon particles are used instead of the zirconium oxide particles.

(Example 6)
A porous diaphragm is produced in the same manner as in Example 2 as a first porous diaphragm. Next, an aqueous dispersion mixed solution of tungsten oxide fine particles having a particle diameter of 100 nm to 1 μm and polyvinylidene fluoride particles is applied to a glass cloth with a thickness of 100 μm as a second porous diaphragm, and dried.

An electrode unit is formed in the same manner as in Example 2 except that each of the porous membranes is used. Using this electrode unit, an electrolytic device having the same configuration as that shown in FIG. 1 is produced.

Using this electrolytic device, electrolysis is carried out at a voltage of 4.1 V and a current of 1.5 A, and sodium hypochlorite water on the first electrode (anode) 20 side and sodium hydroxide water on the second electrode (cathode) 22 side Generate Even after 1000 hours of continuous operation, almost no increase in voltage or change in product concentration is observed, and stable electrolytic processing can be performed.

(Example 7)
A porous diaphragm is produced in the same manner as in Example 2 as a first porous diaphragm. Next, an aqueous dispersion mixed liquid of tungsten oxide fine particles having a particle diameter of 100 nm to 1 μm and polyvinylidene fluoride particles is applied to a glass cloth with a thickness of 100 μm as a second porous diaphragm and dried. Next, it is immersed in a 5% isopropanol solution of tetraisopoloxysilane and evacuated to the atmosphere. It dries at 80 degreeC in air | atmosphere for 1 hour, and makes a 2nd porous diaphragm.

(Comparative example 1)
An electrolytic device was prepared in the same manner as in Example 1, except that a porous polystyrene membrane was used instead of the porous diaphragm produced by applying and baking the porous diaphragm coating material to the first and second electrodes, respectively. Made.

Using this electrolytic device, electrolysis is carried out at a voltage of 4 V and a current of 1.5 A, to generate hypochlorous acid water on the anode side and sodium hydroxide water on the cathode side. On the anode side, mixing of sodium chloride is observed. After 1000 hours of continuous operation, a significant increase in voltage and a decrease in product concentration are observed, and the long-term stability is lacking.

(Comparative example 2)
A first porous diaphragm is produced in the same manner as in Example 2 except that tetraisopropoxysilane is used instead of tetraisopropyzirconium (IV), and the other steps are carried out in the same manner as in Example 2. Was produced.

The zeta potential of this first porous diaphragm is -40 mV at pH 4. In this electrolytic device, a voltage of 5 V and a current of 1.5 A require a high voltage for electrolysis.

(Example 8)
A 75 μm thick glass cloth (Nittobo 3313) is mechanically pressed at 100 ° C. to be integrated with a 30 μm thick polytetrafluoroethylene porous membrane (Sumitomo Electric Co., Pore Flon HPW-010-30). A porous polytetrafluoroethylene membrane pressed with a glass cloth is dip-coated in a dispersion obtained by diluting a polytetrafluoroethylene fine particle dispersion (Mitsui Dupont Fluorochemical 31-JR) by a factor of 2 and a temperature of 200 ° C. Heat for a minute. The amount of polytetrafluoroethylene particles added is 16 mg / cm ² . Next, this porous membrane is dip-coated in a 5% isopropanol solution of tetraisopropoxyzirconium (IV) and dried at 200 ° C. in the air for one hour to form

porous diaphragms

24 and 27. The zeta potential at pH 4 of this porous diaphragm surface is -10 mV. Also, the zeta potential at pH 8 to 10 is -40 mV. The water permeability is 0.5 mL / min / cm ² / MPa.

A flat titanium plate having a thickness T1 of 0.5 mm is prepared as the base 21 of the first electrode.

The titanium plate is etched in the same manner as in the steps shown in FIGS. 11A to 11C to produce the first electrode 20 usable in the first embodiment. The electrodes have a length of 15 cm in the water flow direction and a width of 10 cm.

The thickness (the depth of the first recess) of the region including the first recess 40 having a small area in the first electrode 20 is 0.1 mm, and the thickness of the region including the second recess 42 having a large area (a second recess Depth) is 0.4 mm. The first concave hole portion 40 is a rounded diamond (the angle of the apex of the extrapolated diamond is 60 ° and 120 °) as shown in FIGS. 9A and 9B. The through holes are also rounded diamonds. The second recess 42 is also diamond shaped, and one side of the diamond is approximately 3.6 mm.

The etched electrode substrate 21 is treated at 80 ° C. for 1 hour in a 10 wt% aqueous solution of oxalic acid. Further, it is anodized at 10 V for 2 hours in a mixed aqueous solution of 1 M ammonium sulfate and 0.5 M ammonium fluoride. Next, a solution prepared by adding 1-butanol to 0.25 M (Ir) to iridium chloride (IrCl ₃ · n H ₂ O) is applied to the first surface 21 a of the electrode substrate 21 and then dried. The catalyst layer 28 is formed by calcining. In this case, drying is carried out at 80 ° C. for 10 minutes, and calcination is carried out at 450 ° C. for 10 minutes. An electrode substrate obtained by repeating such application, drying and firing five times is referred to as a first electrode (anode) 20.

Instead of forming the iridium oxide catalyst layer 28, a second electrode (counter electrode, cathode) 22 is formed in the same manner as the first electrode 21 except that platinum is sputtered as a catalyst layer. A porous polystyrene having a thickness of 5 mm is used as a holder 25 for holding the electrolytic solution. The first electrode 20, the porous diaphragm 24, the porous polystyrene 25, the porous diaphragm 27, and the second electrode 22 are stacked and fixed using silicone packing and a screw, to form an electrode unit 12. The electrode unit 12 is placed in the electrolytic cell 11, and the anode chamber 16 and the cathode chamber 18 and the intermediate chamber 19 provided with the porous polystyrene 25 disposed between the electrodes are provided by the partition 14 and the electrode unit 12. It is divided into three rooms.

The anode chamber 16 and the cathode chamber 18 of the electrolytic cell 11 are each formed of a container made of vinyl chloride in which a straight flow path is formed. A controller 36, a power source 30, a voltmeter 34, and an ammeter 32 are installed. Piping and a pump for supplying water from the water supply source 106 to the anode chamber 16 and the cathode chamber 18 are connected to the electrolytic cell 11, and the water supply lines 104 and 105 are secured. Furthermore, a line L4 for extracting hypochlorous acid water from the anode chamber 16 and a line L5 for extracting alkaline water from the cathode chamber 18 can be provided. Connect a saturated saline solution tank 107 and a pipe for circulating and supplying a saturated saline solution to the holder (porous polystyrene) 25 of the electrode unit 12 and a pump, and introduce an electrolyte containing chloride ions into the electrolytic cell The line L1 and the line 108 for collecting the excess electrolyte are secured. Further, as the water quality sensor 70, a conductivity sensor is installed in the outlet line of acidic electrolyzed water, and a pH sensor is installed in the outlet line of alkaline electrolyzed water. Thereby, the electrolytic device which has the same composition as Drawing 10 is obtained.

Electrolysis is performed at a flow rate of 5 L / min, a voltage of 7.5 V, and a current of 30 A using the electrolytic device 10, and hypochlorous acid water is on the first electrode (anode) 20 side, and hydrogen is on the second electrode (cathode) 22 side. And produce sodium hydroxide water. No increase in voltage is observed during 2000 hours of continuous operation of this device. Also, the increase rate of the permeability of the porous membrane is 0% (within the measurement error).

(Comparative example 3)
An electrolytic device is produced in the same manner as in Example 8 except that polyphenylene sulfide cloth is used instead of glass cloth. Electrolysis is performed at a flow rate of 5 L / min, a voltage of 7.5 V, and a current of 30 A to generate hypochlorous acid water on the first electrode (anode) 20 side and hydrogen and sodium hydroxide water on the second electrode (cathode) 22 side. Do. In 1300 hours of continuous operation of this device, the salt concentration in the electrolytic water rises rapidly and the porous diaphragm breaks.

(Example 9)
A porous diaphragm is prepared in the same manner as in Example 8 except that a polyvinylidene fluoride dispersion is used instead of the polytetrafluoroethylene dispersion. The amount of polyvinylidene fluoride particles added is 18 mg / cm ² . The zeta potential at pH 4 of this porous diaphragm surface is -14 mV. Also, the zeta potential at pH 8 to 10 is −45 mV. The water permeability is 1.0 mL / min / cm ² / MPa. An electrolytic device is produced in the same manner as in Example 1 using this porous membrane. Electrolysis is performed at a flow rate of 5 L / min, a voltage of 7.8 V, and a current of 30 A, producing hypochlorous acid water on the first electrode (anode) 20 side and hydrogen and sodium hydroxide water on the second electrode (cathode) 22 side. Do. There is no increase in voltage in 1000 hours of continuous operation of this device. In addition, the increase in permeability of the porous membrane is 2%.

(Example 10)
A 75 μm thick glass cloth (Nittobo 3313) is mechanically pressed at 80 ° C. and integrated as a porous diaphragm with a 100 μm thick polyethylene porous membrane (Nitto Denko San Map LC). A dispersion obtained by diluting a polytetrafluoroethylene fine particle dispersion (Mitsui Dupont Fluorochemical 31-JR) with a double dilution is drop-coated on a polytetrafluoroethylene porous membrane pressed with a glass cloth, and the dispersion is applied for 20 minutes at 100 ° C. Heat up. The amount of polytetrafluoroethylene particles added is 14 mg / cm ² . Next, the obtained porous membrane is dip-coated in a 5% isopropanol solution of tetraisopropoxyzirconium (IV), and dried at 100 ° C. in the air for 1 hour to form

porous diaphragms

24 and 27. The zeta potential at pH 4 of this porous diaphragm surface is -5 mV. Also, the zeta potential at pH 8 to 10 is -30 mV. The water permeability is 5 mL / min / cm ² / MPa. An electrolytic device is produced in the same manner as in Example 1 using this porous membrane. Electrolysis is performed at a flow rate of 5 L / min, a voltage of 8.5 V, and a current of 30 A to generate hypochlorous acid water on the first electrode (anode) 20 side and hydrogen and sodium hydroxide water on the second electrode (cathode) 22 side. Do. There is no increase in voltage in 1000 hours of continuous operation of this device. In addition, the increase in permeability of the porous membrane is 5%.

(Comparative example 4)
An electrolytic device is produced in the same manner as in Example 10 except that a polypropylene / polyethylene composite porous membrane is used instead of the polyethylene porous membrane. Electrolysis is performed at a flow rate of 5 L / min, a voltage of 8.7 V, and a current of 30 A, producing hypochlorous acid water on the first electrode (anode) 20 side and hydrogen and sodium hydroxide water on the second electrode (cathode) 22 side. Do. The continuous operation of this apparatus for 640 hours causes the salt concentration in the electrolytic water to rise rapidly, and the porous diaphragm breaks.

(Example 11)
A polytetrafluoroethylene fine particle dispersion liquid is applied to a porous film pressed together with a glass cloth in the same manner as in Example 8 except that the dip coating speed is increased to make the addition amount of polytetrafluoroethylene fine particles 13 mg / cm ^2. Dip coat. After dip coating, the obtained porous film is dip coated with a 5% isopropanol solution of tetraisopropoxyzirconium (IV), and dried at 200 ° C. in the air for 1 hour to form

porous diaphragms

24 and 27. The zeta potential at pH 4 of this porous diaphragm surface is -10 mV. Also, the zeta potential at pH 8 to 10 is -40 mV. The water permeability is 4 mL / min / cm ² / MPa. An electrolytic device is produced in the same manner as in Example 1 using this porous membrane. Electrolysis is performed at a flow rate of 5 L / min, a voltage of 8.2 V, and a current of 30 A to generate hypochlorous acid water on the first electrode (anode) 20 side and hydrogen and sodium hydroxide water on the second electrode (cathode) 22 side. Do. There is no increase in voltage in 1000 hours of continuous operation of this device. Also, the increase rate of the permeability of the porous membrane is 1%.

(Example 12)
As a porous diaphragm, a 30 μm-thick polytetrafluoroethylene porous membrane (Sumitomo Electric Pflon HPW-010-30) is integrated by mechanically pressing a 75 μm-thick glass cloth (Nittobo 3313) at 100 ° C. 10 wt% of titanium oxide fine particles having a particle diameter of 200 nm is mixed with a dispersion obtained by diluting a polytetrafluoroethylene fine particle dispersion (Mitsui-Dupont Fluorochemical 31-JR) twice. The porous membrane is dip coated in the mixed dispersion and heated at 200 ° C. for 20 minutes. The amount of polytetrafluoroethylene and titanium oxide particles added is 18 mg / cm ² . Next, the obtained porous film is dip-coated in a 5% isopropanol solution of tetraisopropoxyzirconium (IV), and dried at 300 ° C. in the air for 1 hour to form

porous diaphragms

24 and 27. The zeta potential at pH 4 of this porous diaphragm surface is -7 mV. Also, the zeta potential at pH 8 to 10 is −45 mV. The permeability is 0.4 mL / min / cm ² / MPa. An electrolytic device is produced in the same manner as in Example 8 using this porous membrane. Electrolysis is performed at a flow rate of 5 L / min, a voltage of 7.2 V, and a current of 30 A, producing hypochlorous acid water on the first electrode (anode) 20 side and hydrogen and sodium hydroxide water on the second electrode (cathode) 22 side. Do. There is no increase in voltage in 1000 hours of continuous operation of this device. Also, the increase rate of the permeability of the porous membrane is 1%.

(Example 13)
A 75 μm thick glass cloth (Nittobo 3313) is mechanically pressed at 100 ° C. and integrated as a porous diaphragm with a polyvinylidene fluoride porous membrane (Fuji Kogyo). 10 wt% of titanium oxide fine particles having a particle diameter of 200 nm is mixed with a dispersion obtained by diluting a polytetrafluoroethylene fine particle dispersion (Mitsui-Dupont Fluorochemical 31-JR) twice. The porous membrane is dip coated in the mixed dispersion and heated at 200 ° C. for 20 minutes. The amount of polytetrafluoroethylene and titanium oxide particles added is 18 mg / cm ² . Next, the obtained porous film is dip-coated in a 5% isopropanol solution of tetraisopropoxyzirconium (IV), and dried at 300 ° C. in the air for 1 hour to form

porous diaphragms

24 and 27. The zeta potential at pH 4 of this porous diaphragm surface is -5 mV. Also, the zeta potential at pH 8 to 10 is -40 mV. The water permeability is 0.3 mL / min / cm ² / MPa. An electrolytic device is produced in the same manner as in Example 8 using this porous membrane. Electrolysis is performed at a flow rate of 5 L / min, a voltage of 7.4 V, and a current of 30 A to generate hypochlorous acid water on the first electrode (anode) 20 side and hydrogen and sodium hydroxide water on the second electrode (cathode) 22 side. Do. There is no increase in voltage in 1000 hours of continuous operation of this device. Also, the increase rate of the permeability of the porous membrane is 1%.

(Example 14)
As a porous diaphragm, a 30 μm-thick polytetrafluoroethylene porous membrane (Sumitomo Electric Pflon HPW-010-30) is integrated by mechanically pressing a 75 μm-thick glass cloth (Nittobo 3313) at 100 ° C. 10 wt% of zirconium oxide fine particles having a particle size of 100 nm are mixed with a 10% solution of polyvinylidene fluoride in N-methylpyrrolidone. The porous membrane is dip coated into the mixed solution and heated at 100 ° C. for 10 minutes under vacuum. The amount of polyvinylidene fluoride and zirconium oxide fine particles added is 16 mg / cm ² . Next, the obtained porous film is dip-coated in a 5% isopropanol solution of tetraisopropoxyzirconium (IV), and dried at 300 ° C. in the air for 1 hour to form

porous diaphragms

24 and 27. The zeta potential at pH 4 of this porous diaphragm surface is -8 mV. Also, the zeta potential at pH 8 to 10 is −45 mV. The water permeability is 0.3 mL / min / cm ² / MPa. An electrolytic device is produced in the same manner as in Example 8 using this porous membrane. Electrolysis is performed at a flow rate of 5 L / min, a voltage of 7.0 V, and a current of 30 A to generate hypochlorous acid water on the first electrode (anode) 20 side and hydrogen and sodium hydroxide water on the second electrode (cathode) 22 side. Do. There is no increase in voltage in 1000 hours of continuous operation of this device. Also, the increase rate of the permeability of the porous membrane is 1.5%.

(Example 15)
As a porous diaphragm, a 30 μm thick polytetrafluoroethylene porous membrane (Sumitomo Electric Pflon HPW-010-30) and a 100 μm thick polyethylene porous membrane (Nitto Denko Sun Map LC) are laminated, and the polyethylene porous membrane side is formed. Integrated by mechanically pressing a 75 μm thick glass cloth (Nittobo 3313) at 80 ° C. 10 wt% of zirconium oxide fine particles having a particle size of 100 nm are mixed with a 10% solution of polyvinylidene fluoride in N-methylpyrrolidone. The porous membrane is dip coated into the mixed solution and heated at 100 ° C. for 10 minutes under vacuum. The amount of polyvinylidene fluoride and zirconium oxide fine particles added is 17 mg / cm ² . Next, the obtained porous film is dip-coated in a 5% isopropanol solution of tetraisopropoxyzirconium (IV), and dried at 300 ° C. in the air for 1 hour to form

porous diaphragms

24 and 27. The zeta potential at pH 4 of this porous diaphragm surface is -10 mV. Also, the zeta potential at pH 8 to 10 is -40 mV. The water permeability is 0.2 mL / min / cm ² / MPa. An electrolytic device is produced in the same manner as in Example 8 using this porous membrane. Electrolysis is performed at a flow rate of 5 L / min, a voltage of 7.5 V, and a current of 30 A to generate hypochlorous acid water on the first electrode (anode) 20 side and hydrogen and sodium hydroxide water on the second electrode (cathode) 22 side. Do. There is no increase in voltage in 1000 hours of continuous operation of this device. In addition, the increase in permeability of the porous membrane is 0.5%.

(Example 16)
As shown in FIG. 13, this electrolytic device 310 has an anode chamber 316 arranged to surround the cathode chamber 318 and the cathode chamber 318 instead of the electrolytic cell 11, and there is no flow path and piping, and natural convection is achieved. It has the same configuration as that of FIG. 1 except that a batch type electrolytic cell 311 in which a water flow is formed is used. The capacities of the anode chamber 316 and the cathode chamber 318 are 2 L and 0.1 L, respectively, and an electrode unit manufactured in the same manner as in Example 1 is used. However, the size of the electrode is 4 × 3 cm.

Electrolysis is performed at a voltage of 7.3 V and a current of 2, 6 A for 5 minutes to generate hypochlorous acid water on the first electrode (anode) side and hydrogen and sodium hydroxide water on the second electrode (cathode) side. There is no increase in voltage in 1000 hours of continuous operation of this device. Also, no change in the permeability of the porous membrane is observed.

The present invention is not limited to the above embodiment as it is, and at the implementation stage, the constituent elements can be modified and embodied without departing from the scope of the invention. In addition, various inventions can be formed by appropriate combinations of a plurality of constituent elements disclosed in the above embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components in different embodiments may be combined as appropriate.

DESCRIPTION OF SYMBOLS 10 Electrolytic device 11 Electrolytic cell 12 Electrode unit 14 Partition wall 16 Anode chamber 18 Cathode chamber 19 Intermediate chamber (electrolyte solution chamber) 20 first electrode (anode) 21 23: base material, 22: second electrode (counter electrode, cathode), 21a, 23a: first surface, 21b, 23b: second surface, 24, 27: porous diaphragm, 25: support body, 28: catalyst layer , 30: power source, 32: ammeter, 34: voltmeter, 40, 44: first hole, 42, 46: second hole, 50: resist film, 51: porous polytetrafluoroethylene film, porous Vinylidene fluoride membrane or porous polyethylene membrane, 52: porous composite membrane, 53: inorganic oxide, 54: glass fiber, 55: fluorocarbon polymer, 60: bridge, 70: water quality sensor

Claims

Composite comprising glass fiber and fluorine polymer formed on the porous membrane and at least one porous membrane of porous polytetrafluoroethylene membrane, porous polyvinylidene fluoride membrane, and porous polyethylene membrane A laminate comprising a membrane and
A covering layer formed on at least one surface of the laminate, the covering layer comprising at least one inorganic oxide selected from the group consisting of titanium oxide, silicon oxide, aluminum oxide, zirconium oxide, tungsten oxide, and zircon Porous diaphragm to be equipped.
The porous diaphragm according to claim 1, having a water permeability of 0.1 mL / min / cm 2 / MPa or more and 6 mL / min / cm 2 / MPa or less.
The porous diaphragm according to claim 1, wherein the glass fiber is a glass cloth.
The porous film according to any one of claims 1 to 3, wherein the porous film comprises at least one particle selected from the group consisting of titanium oxide, silicon oxide, aluminum oxide, zirconium oxide, tungsten oxide, zeolite, and zircon. Porous diaphragm as described.
Laminating the glass fiber on at least one of the porous membrane of the porous polytetrafluoroethylene membrane, the porous polyvinylidene fluoride membrane, and the porous polyethylene membrane, and the porous membrane through the glass fiber Applying a fluorine-containing polymer-containing liquid thereon to form a composite film comprising the glass fiber and the fluorine-containing polymer on the porous film, and at least one of a laminate of the porous film and the composite film Applying an inorganic oxide precursor solution to the surface to form a coating layer containing the inorganic oxide.
The method for producing a porous diaphragm according to claim 5, wherein the laminating step uses a heating press.
Positive electrode,
A negative electrode disposed opposite to the positive electrode;
An electrode unit for producing hypochlorous acid water, comprising: a first porous diaphragm containing a first inorganic oxide exhibiting a positive zeta potential in a pH range of 2 to 6;
A second porous diaphragm is further formed on the positive electrode side of the negative electrode, wherein a second porous diaphragm containing a second inorganic oxide having a negative zeta potential in a pH range of 8 to 10 is formed. The electrode unit for hypochlorous acid water manufacture as described.
The electrode unit for hypochlorous acid water manufacture of Claim 7 or 8 which applies the porous diaphragm of any one of Claim 1 to 4 as said porous diaphragm.
The positive electrode is open to the first surface, a second surface opposite to the first surface, a plurality of first holes opened to the first surface, and the second surface. 10. A plurality of second holes having a diameter larger than that of the first hole, and a plurality of first holes communicating with one of the second holes. An electrode unit for producing hypochlorous acid water according to any one of the items 1 to 4.
The electrode unit for producing hypochlorous acid water according to any one of claims 7 to 10, wherein an opening area of the first hole portion is 0.01 mm 2 to 4 mm 2 .
The hypochlorous acid water according to any one of claims 7 to 11, wherein the first inorganic oxide is at least one selected from zirconium oxide, titanium oxide, zircon and aluminum oxide. Manufacturing electrode unit.
The first inorganic oxide according to any one of claims 7 to 12, wherein the first inorganic oxide is distributed at a higher density on the surface of the first porous diaphragm than the inside of the first porous diaphragm. Electrode unit for the production of hypochlorous acid water.
14. The method according to claim 7, wherein the second inorganic oxide is at least one of zirconium oxide, titanium oxide, silicon oxide, tungsten oxide, zeolite, zircon and aluminum oxide. An electrode unit for producing hypochlorous acid water according to Item.
The first porous diaphragm is a laminate of a first porous layer having a first pore size and a second porous layer having a second pore size different from the first pore size. The electrode unit for hypochlorous acid water production according to any one of the above 14.
The first porous diaphragm further includes a third inorganic oxide different from the first inorganic oxide, and a ratio of the first inorganic oxide to the third inorganic oxide is the first porous. The electrode unit for producing hypochlorous acid water according to any one of claims 7 to 15, which is different in the surface and the inside of the porous diaphragm.
The hypochlorite water generating electrode unit according to any one of claims 7 to 16, further comprising means for holding a liquid or solid electrolyte between the positive electrode and the negative electrode.
The electrode unit for producing hypochlorous acid water according to any one of claims 7 to 17, wherein a surface zeta potential of the first porous diaphragm is larger than -30 mV at pH 4.
The electrode unit for producing hypochlorous acid water according to any one of claims 7 to 18, further comprising a first catalyst layer comprising an electrocatalyst between the positive electrode and the first porous diaphragm.
An electrode unit for producing hypochlorous acid water according to any one of claims 7 to 19, a power supply for applying a voltage to the electrode, and a control apparatus.