JP6585176B2 - Electrode, electrode unit, and electrolysis device - Google Patents

Description

  Embodiments described herein relate generally to an electrode, an electrode unit, and an electrolysis apparatus.

  2. Description of the Related Art In recent years, electrolyzers have been provided that generate electrolyzed water having various functions by electrolyzing water, such as alkali ion water, ozone water, or hypochlorous acid water. Among electrolyzed water, hypochlorous acid water has an excellent sterilizing power and is safe for the human body and approved as a food additive. Electrolyzers are also used for hydrogen production and the like.

  As an electrolysis apparatus, for example, an electrolyzed water generation apparatus having a three-chamber electrolysis tank has been proposed. The inside of the electrolytic cell is divided into three chambers, an intermediate chamber, and an anode chamber and a cathode chamber located on both sides of the intermediate chamber, by a cation exchange membrane and an anion exchange membrane. The anode chamber and the cathode chamber are provided with an anode and a cathode, respectively. As an electrode, a porous electrode is used in which a large number of holes are processed by expanding, etching, or punching on a metal plate base material.

  In such an electrolysis apparatus, for example, salt water is passed through the intermediate chamber, and water is circulated through the anode chamber and the cathode chamber, respectively. By electrolyzing the salt water in the intermediate chamber at the cathode and the anode, hypochlorous acid water and chlorine are generated at the anode, and sodium hydroxide water and hydrogen are generated at the cathode chamber. The generated hypochlorous acid water is used as sterilizing / disinfecting water, and sodium hydroxide water is used as washing water. Hydrogen is used as hydrogen water or fuel. In particular, when chlorine and hydrogen are mainly produced, electrolysis is performed with a larger current.

  When conducting a large amount of electrolysis by flowing a large current among these electrolysis, if the current concentrates on a part of the electrode, the catalyst in the part may be peeled off, or the porous film or the electrolyte film in contact with the part may easily deteriorate. Rises and the service life is shortened.

JP 2014-101549 A Japanese Patent No. 4746629

  An object of an embodiment of the present invention is to provide an electrolytic electrode, an electrode unit, and an electrolytic device that have a long life even at a high current density.

The electrode according to the embodiment has a first surface, a second surface facing the first surface, a base material having a plurality of through holes penetrating from the first surface to the second surface, and the first surface. There are a plurality of first recesses that open, and a plurality of second recesses that are open on the second surface and have a larger opening area than the first recess, and the radius of curvature of the opening of the first recess is 0. 0. der least 01mm is, and the catalyst layer is provided on said first surface.

FIG. 1 is a diagram schematically illustrating an example of an electrolysis apparatus according to an embodiment. FIG. 2A is a schematic diagram illustrating an example of the shape of the electrode according to the embodiment. FIG. 2B is a schematic diagram illustrating an example of the shape of the minimum cross-sectional area of the through hole of the electrode according to the embodiment. FIG. 2C is a diagram schematically illustrating a cut surface along the line AA in FIG. 2A. FIG. 2D is a diagram for explaining the radius of curvature of the edge portion of the first recess. FIG. 3A is an exploded perspective view illustrating an example of an electrode unit to which the electrode according to the embodiment can be applied. FIG. 3B is a schematic diagram illustrating an example of the shape of the minimum cross-sectional area of the through hole of the electrode according to the embodiment. FIG. 3C is a schematic diagram illustrating a cut surface of the BB line illustrated in FIG. 3A. FIG. 3D is a schematic diagram illustrating a cut surface of the CC line illustrated in FIG. 3A. FIG. 4A is an exploded perspective view illustrating an example of an electrode unit to which the electrode according to the embodiment can be applied. FIG. 4B is a schematic diagram illustrating a cut surface of the DD line of FIG. 4A. FIG. 5 is a diagram schematically illustrating another example of the electrolysis apparatus according to the embodiment. Drawing 6A is a figure showing an example of the manufacturing method of the electrode used for an embodiment. Drawing 6B is a figure showing an example of the manufacturing method of the electrode used for an embodiment. Drawing 6C is a figure showing an example of the manufacturing method of the electrode used for an embodiment. FIG. 6D is a diagram illustrating an example of an electrode manufacturing method used in the embodiment. Drawing 6E is a figure showing an example of the manufacturing method of the electrode used for an embodiment. Drawing 6F is a figure showing an example of the manufacturing method of the electrode used for an embodiment. FIG. 7 is a schematic diagram illustrating an example of the configuration of the electrode and the porous diaphragm used in the embodiment. FIG. 8 is a diagram schematically illustrating an example of the electrolysis apparatus according to the embodiment. FIG. 9 is a diagram schematically illustrating an example of the electrolysis apparatus according to the embodiment.

  The electrode according to the embodiment includes a first surface, a second surface facing the first surface, a base material having a plurality of through holes penetrating from the first surface to the second surface, and a plurality of openings opened on the first surface. The first recess and the second surface have a plurality of second recesses having an opening area wider than the first recess, and the radius of curvature of the edge of the opening of the first recess is 0.01 mm or more. .

  The electrode unit according to the embodiment is an electrode unit using the electrode as a first electrode, and is arranged to face the first electrode having the first surface and the second surface and the first surface of the first electrode. A second electrode; a porous diaphragm provided on a first electrolyte holding surface of the first electrode; and an electrolyte holding structure provided between the porous diaphragm and the second electrode.

  Moreover, the electrolysis apparatus which concerns on embodiment is an example of the electrolysis apparatus to which the said electrode and the electrode unit using the same are applied. This electrolysis apparatus has an electrolytic cell, an electrode unit incorporated in the electrolytic cell, a first electrode chamber and a second electrode chamber partitioned by the electrode unit. The electrode unit can be equipped with a mechanism for applying a voltage, for example, a power source for applying a voltage to the electrode, a control device, and the like.

  The first electrode chamber is, for example, an anode chamber, the second electrode chamber is, for example, a cathode chamber, a line for introducing an electrolytic solution containing chloride ions into an electrolytic cell, a line for taking out acidic electrolyzed water from the anode chamber, and a cathode chamber A line for taking out alkaline electrolyzed water from can be further provided. A water quality sensor for monitoring water quality may be installed in the line. In particular, a conductivity sensor and / or a pH sensor is preferable for a line for extracting acidic electrolyzed water, and a pH sensor and / or a sodium ion sensor is preferable for a line for extracting alkaline electrolyzed water. A conductivity sensor that can measure about 0 to 20 mS / cm is particularly preferable because it can be detected when a small amount of ionic impurities are mixed in acidic electrolyzed water.

  Hereinafter, 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 diagram for promoting the embodiment and its understanding, and its shape, dimensions, ratio, etc. are different from the actual device, but these are considered in consideration of the following description and known techniques. The design can be changed as appropriate. For example, in the drawing, the electrode is drawn on a plane, but it may be bent according to the shape of the electrode unit or may be cylindrical.

  FIG. 1 is a diagram schematically illustrating an example of an electrolysis apparatus according to an embodiment.

  The electrolysis 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 partitioned into three chambers by a partition wall 14 and an electrode unit 12, an anode chamber 16, a cathode chamber 18, and an intermediate chamber 19 formed between the electrodes. It has been.

  The electrode unit 12 includes a first electrode 20 positioned in the anode chamber 16, a second electrode (counter electrode) 22 positioned in the cathode chamber 18 and having a plurality of predetermined through holes, and a first electrode 20. A catalyst layer 28 is formed on one surface 21a, and has a porous diaphragm (an electrolyte membrane can be used) 24 thereon. Another porous diaphragm 27 can be provided on the first surface 23 a of the second electrode 22. The first electrode 20 and the second electrode 22 face each other in parallel with a gap therebetween, and form an intermediate chamber (electrolyte chamber) 19 for holding an electrolyte solution between the porous diaphragms 24 and 27. . A holding body 25 that holds the electrolytic solution may be provided in the intermediate chamber 19. The first electrode 20 and the second electrode 22 may be connected to each other by a plurality of bridges 60 having insulating properties.

  The electrolysis apparatus 10 includes a power supply 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 power supply 30. An ammeter 32 and a voltmeter 34 may be provided.

  As shown in the figure, the first electrode 20 has a porous structure in which a large number of through holes are formed in a base material 21 made of, for example, a rectangular metal plate. The substrate 21 has a first surface 21a and a second surface 21b that faces the first surface 21a substantially in parallel. The distance between the first surface 21a and the second surface 21b, that is, the plate thickness is formed at T1. The first surface 21 a faces the porous diaphragm 24, and the second surface 21 b faces the anode chamber 16. An anodic oxide film (not shown) may be formed on the surface 21a.

  A plurality of first recesses 40 are formed on the first surface 21a of the base material 21 and open to the first surface 21a. A plurality of second recesses 42 are formed on the second surface 21b and open to the second surface 21b. 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. Further, the number of recesses is preferably such that the first recesses 40 are formed more than the second recesses 42. The depth of the first recess 40 is T2, the depth of the second recess 42 is T3, and T2 + T3 = T1. In the embodiment, for example, T2 <T3. In the figure, a through hole in which the first recess 40 and the second recess 42 are connected is formed, but there may be a recess that is not connected or a part of which is connected. The base material 21 is the same base material, and is not an electrode in which different base materials are partially laminated by welding or the like. When different base materials are laminated, hypochlorous acid tends to stay on the base material contact surface, and the generation efficiency decreases. In addition, current concentration tends to concentrate at the junction, and catalyst deterioration tends to occur.

  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. The number of the recesses is preferably such that the first recesses 40 are formed more than the second recesses 42. The stress due to the end of the recess on the porous membrane is relieved, and the lifetime of the porous membrane is increased. In addition, since the number of second recesses can be reduced, the electrical resistance can be reduced, which is advantageous in place of wiring and mechanical holding.

  At least one of the first electrode 20 and the second electrode 22 used in the electrolysis apparatus 10 according to the embodiment has a plurality of predetermined through holes.

  2A, 2B, and 2C are schematic views illustrating an example of an electrode that can be used as the first electrode 20 in FIG.

  FIG. 2A is a view of the first electrode 20 as viewed from the second surface 21b.

  FIG. 2B is a schematic diagram showing the shape of the minimum cross-sectional area parallel to the base material of the through hole.

  FIG. 2C is a diagram schematically illustrating a cut surface along the line AA in FIG. 2A.

  FIG. 2D is a diagram for explaining the radius of curvature of the edge portion of the first recess.

  In the drawing, the through hole is formed by connecting the first recess 40 and the second recess 42.

  As shown in the figure, the predetermined plurality of through holes provided in the first electrode 20 are diamonds with rounded corners. 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 hole. The concave section can be tapered or curved so that the inside is narrowed.

  FIG. 2D shows an enlarged view of the edge portion 48 of the first recess in FIG. 2C, where C1 is the radius of curvature of the edge portion 48.

  As shown in FIGS. 2C and 2D, in the embodiment, the curvature radius of the edge portion 48 excluding the catalyst of the first recess is defined as 0.01 mm or more.

  This has the following effects. First, current concentration at the edge portion is alleviated, catalyst peeling is reduced, voltage rise is prevented, and deterioration of the porous diaphragm in the vicinity of the electrode is reduced. In addition, uniform catalyst formation on the edge portion is facilitated. Furthermore, embrittlement due to the generated hydrogen can be mitigated when used for the cathode. Furthermore, wear of the electrode due to mechanical contact between the electrode and the porous diaphragm, tearing of the porous diaphragm, and the like can be alleviated. In particular, it is possible to mitigate deterioration that occurs at the start or stop of operation in which the water pressure tends to fluctuate.

  When the curvature radius is smaller than 0.01 mm, the above-described effect becomes insufficient. The curvature radius is preferably 0.02 mm or more. More preferably, it is 0.04 mm or more. However, if it is larger than 2 mm, the through hole tends to be too small. The radius of curvature of the catalyst layer is also preferably 0.01 mm or more. When it is smaller than 0.01 mm, the life of the diaphragm tends to be shortened due to current concentration. The thickness of the catalyst layer is preferably 0.1 μm to 12 μm. If it is thinner than 0.1 μm, the lifetime is shortened. If it is thicker than 12 μm, the efficiency per catalyst amount becomes small and the cost becomes high. It is more preferably 0.4 μm or more and 8 μm or less, and further preferably 1 μm or more and 4 μm or less.

  The first recess can be formed on the entire first surface. In this case, the 1st recessed part which does not penetrate to the 2nd surface exists. Since the first recess not penetrating is excellent in holding chloride ions, conditions such as low chloride ion concentration, for example, the concentration of chloride held in the intermediate chamber 19 is low, or the pressure in the intermediate chamber 19 is the anode chamber. When the pressure is lower than 16, it is effective for improving the generation efficiency of hypochlorous acid and lowering the driving voltage.

  As shown in FIG. 2B, the opening of the through hole used in the embodiment is based on the cross section having the smallest cross sectional area.

  As the shape of the second recess 42, a diamond shape in which a plurality of first recesses 40 can be used.

Alternatively, other shapes in which a plurality of first recesses 40 can be used. If the apex of the taper or curve is rounded, the flow of water flow is smooth, current concentration can be prevented, and the curvature is preferably 0.01 mm or more.

  As shown in FIG. 2A, the plurality of first recesses 40 have substantially the same size, but the plurality of first recesses 40 provided in the electrode substrate have a minimum opening diameter passing through the center of the opening of the first recess 40 constituting the through hole. Of the through holes, the aperture ratio of the through hole located at the center of the electrode substrate can be different from the aperture ratio of the through hole located at the peripheral edge of the electrode substrate. When the aperture ratio of the through hole located at the center is smaller than that at the periphery, the electrical resistance at the center is reduced, and current supply to the center is facilitated. On the other hand, if the opening ratio of the through hole located in the central portion is larger than that in the peripheral portion, the gas is likely to escape. Which of the opening ratios of the central part and the peripheral part is increased can be selected in consideration of the operating conditions and the relationship with other members.

Elementary reaction at the anode where hypochlorous acid is generated
M + H ₂ O → M−OH + H ⁺ + e ⁻ (1)
M−OH → MO−H ⁺ + e ⁻ (2)
M−O + Cl ⁻ + H ⁺ → M + HClO (3)
As a total
H ₂ O + Cl ⁻ → HClO + H ⁺ + 2e ⁻ (4)
It is.

On the other hand, in the cathode
2H ₂ O + 2e ⁻ → H ₂ + 2OH ⁻ (5)
All reactions include cations
2NaCl + 3H ₂ O → HClO + HCl + 2NaOH + H ₂ (6)

On the other hand, there may be a side reaction that generates oxygen at the same time.
M + H ₂ O → M−OH + H ⁺ + e ⁻ (1)
M−OH → MO−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 ions required for the reaction is small, the reaction of the reaction formula (7) tends to occur. Therefore, in order to efficiently generate hypochlorous acid, it is necessary to increase the concentration of chloride ions. Chloride ions are supplied from the porous diaphragm side, accumulate at the shielding part of the electrode, and flow out from the opening by diffusion. For this reason, the diffusion distance is important for increasing the concentration of chloride ions. Further, as can be seen from the reaction formula, it is necessary to take out electrons in order to cause the reaction, and current density tends to be uneven at high currents.

  FIG. 3A schematically shows an exploded perspective view showing an example of another electrode unit to which the electrode according to the embodiment can be applied.

  FIG. 3B is a schematic diagram showing the shape of the minimum cross-sectional area parallel to the base material of the through hole.

  FIG. 3C is a schematic diagram illustrating a cut surface of the BB line illustrated in FIG. 3A.

  FIG. 3D is a schematic diagram illustrating a cut surface of the CC line illustrated in FIG. 3A.

  As shown in the drawing, each of the six first recesses 63 has a rectangular shape that reaches from the right end to the left end of the electrode 223 excluding the seal portion 224, and the first recess 63 does not communicate with the second surfaces 221b and 223b. It has a recessed part and the opening part (through-hole) 61 connected to 2nd surface 221b, 223b. The depth of the 1st recessed part which the through-hole 61 is arrange | positioned in the 1st recessed part 63 at intervals of 3 is shallow compared with the 2nd recessed part 62. As shown in FIG. Reference numeral 64 provided at the upper ends of the first electrode 220 and the second electrode 222 is a voltage application port, and the thick beam 65 faces the voltage application direction. The first electrode and the second electrode have the same shape, and different surfaces are displayed in the figure.

  Each of the three second recesses 62 has a rectangular shape that reaches from the upper end to the lower end of the electrode 221 excluding the seal portion. Six through holes respectively arranged in six first recesses (not shown) communicate with one second recess 62. The number density of the first recesses 61 on the first surface 221a is sufficiently larger than the number density of the second recesses 62 on the second surface 221b. In FIG. 3A, the number of openings is shown to be small for easy understanding, but actually, the number of openings is much larger.

  Although any shape is possible as the shape of the through hole of the embodiment, a rectangular shape with a round end, or an ellipse with a rounded corner or a rounded shape is preferable. The shape of the through hole may have irregularities in the outline. Moreover, the end may be a group of a plurality of arcs having different diameters. FIG. 3A shows a part of the electrode. In such a shape, since the end is round, stress concentration on the gap is unlikely to occur. Further, if the opening interval can be made dense, the opening ratio can be increased.

  In the electrode shape of FIG. 3A, hypochlorous acid generated due to the first recess 63 is easy to move, and therefore easily flows out from the through hole. If hypochlorous acid does not flow out, chlorine gas is generated or diffuses to the porous diaphragm side, resulting in low efficiency. This is likely to occur when the chloride ion concentration is high, and is likely to occur when the chloride concentration in the intermediate chamber 19 is high or the pressure in the intermediate chamber 19 is higher than that in the anode chamber 16. Therefore, the electrode structure as shown in FIG. 3A is particularly effective when the chloride concentration in the intermediate chamber 19 is high or the pressure in the intermediate chamber 19 is higher than that in the anode chamber 16.

The opening area of the through hole can be from 0.01 mm ² to 4 mm ² . If it is smaller than 0.01 mm ^2, it will be difficult to discharge reaction products such as gas and hypochlorous acid to the outside, and deterioration of the members will easily occur. When it is larger than 4 mm ² , the electrical resistance increases, and the electrode reaction efficiency tends to decrease. The thickness is preferably 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 62 can be ¹ to 1600 mm ² . The thickness is preferably 4 mm ² to 900 mm ² , more preferably 9 mm ² to 400 mm ² . A concave portion that is elongated in one direction and is connected to the end of the electrode excluding the seal portion, such as a rectangle or an ellipse, is also possible.

The opening area of the first recess 63 may be from 0.01 mm ² in the range larger than the opening area of the small through hole 61 from the second recess 62 to 1600 mm ^2. The smaller the area of the first recess and the greater the number, the greater the length of the edge portion, and the greater the influence of the curvature of the edge. Therefore, it is preferably 0.2 mm ² to 400 mm ² .

  The opening of the second recess 62 can have various shapes such as a square, a rectangle, a rhombus, a circle, and an ellipse. A larger opening diameter of the second recess 62 can improve hypochlorous acid and outgassing, but it cannot be increased because the electrical resistance increases. As illustrated, the opening of the second recess 62 may be a recess that is elongated in one direction, such as a rectangle or an ellipse, and is connected to the end of the electrode excluding the seal portion.

  Also, the opening of the first concave portion 63 can have various shapes such as a square, a rectangle, a rhombus, a circle, and an ellipse. As shown in the figure, an opening that extends in one direction, such as a rectangle or an ellipse, and is connected to the end of the electrode excluding the seal portion is also possible.

  Two recesses that connect from end to end of the first recess and the second recess may be orthogonal or parallel to each other. If it goes straight, gas diffusion is easy. If parallel, chloride ions are easy to collect. Orthogonal means intersecting at an angle of 87 to 93 degrees, and parallel means that the intersecting angle is within 3 degrees.

  Note that the electrode shown in FIG. 3A is provided on the first surface, which has a rectangular through hole with a rounded end, which is the configuration of the second embodiment, and the configuration of the first and third embodiments. Although it has both having the recessed part connected to the other end of the electrode except the seal part, in the third embodiment, either one of the configurations can be omitted.

  Further, in FIG. 3A, the openings 61 are arranged in the direction of the voltage application port 64. As a result, since the beams 65 having a large electrode thickness and a small electrical resistance are arranged in the voltage application direction, power supply is facilitated, and the drive voltage can be reduced.

  The curvature radii of the edge portions 68 of the base material excluding the catalyst of the first recess 63 shown in FIG. 3C are each 0.01 mm or more. Moreover, the curvature radius of the edge part 69 of the 2nd recessed part 62 shown to FIG. 3D is 0.01 mm or more, respectively.

  As a result, current concentration in the edge portion is alleviated, catalyst peeling is reduced, and deterioration of the porous diaphragm in the vicinity of the electrode is reduced. In addition, uniform catalyst formation on the edge portion is also prepared. Further, when used for a cathode, embrittlement due to generated hydrogen can be reduced. Furthermore, wear of the electrode due to mechanical contact between the electrode and the porous diaphragm, tearing of the porous diaphragm, and the like can be alleviated. In particular, it is possible to mitigate deterioration that occurs at the start or stop of operation, in which the water pressure is likely to fluctuate.

  The radius of curvature is preferably 0.01 mm or more. If it is smaller than 0.01 mm, the above effect is small. Preferably it is 0.02 mm or more. More preferably, it is 0.04 mm or more. However, if it is larger than 2 mm, the opening becomes too large. Preferably it is 1 mm or less, More preferably, it is 0.5 mm or less.

  FIG. 4A schematically shows an exploded perspective view showing an example of another electrode unit to which the electrode according to the embodiment can be applied.

  FIG. 4B is a schematic diagram illustrating a cut surface of the DD line of FIG. 4A.

  In FIG. 4A, openings 61 'are arranged in the direction of the voltage application port 64'. As a result, the beams 65 'having a large electrode thickness and a small electrical resistance are arranged in the voltage application direction, so that power supply is facilitated and the driving voltage can be reduced. The first electrode and the second electrode have the same shape, and both surfaces of each electrode have the same structure. In the electrode unit 212 ′, the first recess and the second recess form a through hole 61 ′.

  Similar to the first recess 61 in FIG. 3B, in the electrode 221 ′ and the electrode 223 ′ in FIG. 4A, the first recess 61 ′ constituting the through hole has an elliptical shape.

  Although the electrode structure is schematically shown in FIG. 4A, the number of first recesses, second recesses, and through holes is actually much larger.

  In the first electrode 20 having a porous structure, the through hole 61 ′ is formed by a tapered surface or a curved surface in which the opening on the second surface side is wider than the first surface, thereby forming a porous diaphragm with the opening of the through hole 61 ′. The contact angle with 24 becomes an obtuse angle, and stress concentration on the porous diaphragm 24 can be reduced.

  As shown in FIG. 4B, the curvature radius of the edge portion 72 of the base material excluding the catalyst of the first recess is 0.01 mm or more. As a result, current concentration in the edge portion 72 is alleviated, catalyst peeling is reduced, and deterioration of the porous diaphragm in the vicinity of the electrode is reduced. In addition, uniform catalyst formation on the edge portion is also prepared. Further, when used for a cathode, embrittlement due to generated hydrogen can be reduced. Furthermore, wear of the electrode due to mechanical contact between the electrode and the porous diaphragm, tearing of the porous diaphragm, and the like can be alleviated. In particular, it is possible to mitigate deterioration that occurs at the start or stop of operation, in which the water pressure is likely to fluctuate. The radius of curvature is preferably 0.01 mm or more. If it is smaller than 0.01 mm, the above effect tends to be small. More preferably, it is 0.02 mm or more, More preferably, it is 0.04 mm or more. However, if it is larger than 2 mm, the opening tends to be large.

  FIG. 5 is a diagram schematically illustrating another example of the electrolysis apparatus according to the embodiment.

  As shown in FIG. 5, in addition to the configuration of FIG. 1, a liquid flow path may be provided in the anode chamber 16 and the cathode chamber 18. In some cases, a porous membrane spacer may be provided between the electrode unit 12 and the anode chamber 16 or the cathode chamber 18. Also, 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 extracting acidic electrolytic water from the electrolytic cell, and alkaline electrolysis from the electrolytic cell A line L5 for taking out water may be further provided. Further, a line L7 for circulating an electrolyte containing chloride ions may be provided, or a line for discharging may be provided. Further, the water softener 109 and a line L6 for supplying the water softener 109 with acidic electrolyzed water for adsorbent regeneration from the acidic electrolyzed water reservoir 106 may be further provided. 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. Further, a tank for mixing the acidic waste liquid and the alkaline waste liquid to be close to neutrality may be provided. A water quality sensor 70 may be installed in each line.

  An example of a method for producing the first electrode 20 and the porous diaphragm 24 having the above-described configuration will be described below. 6A to 6F are views showing an example of the electrode manufacturing method according to the embodiment.

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

  As shown in FIGS. 6A and 6B, a single 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 substrate 21.

  As shown in FIG. 6C, the resist films 50a and 50b are exposed using an optical mask (not shown) to produce etching masks 52a and 52b, respectively. The aperture area and aperture ratio are defined by the optical mask.

  As shown in FIG. 6D, the first surface 21a and the second surface 21b of the base material 21 are wet-etched with a solution through the masks 52a and 52b, whereby a plurality of first recesses 40 and a plurality of second recesses are obtained. 42 is formed. Thereafter, the first electrode 20 is obtained by removing the masks 52a and 52b. The planar shapes of the first recess 40 and the second recess 42 can be controlled by an optical mask and etching conditions. By designing the mask, the aperture ratio, aperture area, aperture shape, etc. in the electrode can be freely controlled.

  The taper of the first and second recesses 40 and 42, the shape of the curved surface, and the curvature can be controlled by the material of the substrate 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 so that T2 <T3. In the etching, both surfaces of the base material 21 may be etched simultaneously, or one surface may be etched. The type of etching is not limited to wet etching, and dry etching or the like may be used. In addition to the etching, the first electrode 20 can be manufactured by an expanding method, a punching method, or processing by laser or precision cutting, but the wet etching method is most preferable. It is also possible to adjust the radius of curvature of the edge portion of the first concave portion or the second concave portion to a predetermined value by wet etching after preparing the electrode by another method. The curvature radius tends to increase as the wet etching speed is slower.

  As the base material 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. Titanium is preferable among titanium, chromium, and aluminum. When used for the cathode, titanium, chromium, aluminum, other alloys, and stainless steel are preferable. Among these, stainless steel resistant to hydrogen embrittlement and rust is more preferable, and SUS316L and SUS310S are 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, a noble metal catalyst such as platinum or an oxide catalyst such as iridium oxide is preferably used. Before the anode catalyst is produced, it is preferable to produce minute oxide film irregularities by anodizing the electrode from the viewpoint of improving the adhesion between the catalyst and the substrate.

  The catalyst layer can be provided on at least part of the first surface.

  A first catalyst layer comprising an electrocatalyst provided between the first electrode and the 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.

  You may form so that the quantity per unit area of an electrocatalyst may differ on both surfaces of a 1st electrode. Thereby, a side reaction etc. can be suppressed.

  The surface of the positive electrode on the porous diaphragm side (first surface) is preferably 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 substantial surface area of the electrode tends to decrease, and if it is larger than 3 μm, stress on the porous diaphragm tends to concentrate on the convex portion of the electrode. More preferably, it is 0.02 μm to 2 μm, and further preferably 0.03 μm to 1 μm.

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

  As the porous diaphragms 24 and 27, for example, a laminate of a first porous layer having a first pore diameter and a second porous layer having a second pore diameter different from the first pore diameter can be used. .

  As the membrane used for the porous diaphragm, those having ion selectivity, for example, an ion permeable membrane of a hydrocarbon polymer or an ion permeable membrane of a fluorine polymer can be used.

  The porous diaphragm preferably contains an inorganic oxide. In particular, an inorganic oxide having a positive zeta potential in the region of pH 2 to 6 is preferable for the porous membrane on the positive electrode side. Thereby, the transport performance of the porous diaphragm with respect to anions can be increased in a chemically stable and weakly acidic region.

  Examples of inorganic oxides that can be used include zirconium oxide, titanium oxide, aluminum oxide, tin oxide, zircon, copper oxide, iron oxide, and mixed oxides thereof. Preferably, zirconium oxide, titanium oxide, aluminum 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 an inorganic oxide is produced through hydrolysis of a metal halide or metal alkoxide, a mixture of these may be formed depending on the post-treatment temperature.

  The abundance ratio of the inorganic oxide in the porous diaphragm can vary depending on the location. For example, the abundance ratio of the inorganic oxide can be increased around the pores and on the surface.

  As the inorganic oxide, a composite oxide such as zircon or a mixture of different inorganic oxides can be used. The porous diaphragm may further contain two or more different oxides, and the abundance ratio of each oxide may differ depending on the position of the porous diaphragm. For example, a region containing zirconium oxide having a high bending strength can be present on the surface, and a region containing titanium oxide having a large positive potential can be present inside.

  The zeta potential on the surface of the porous diaphragm can be greater than −30 mV at pH 4. If it is less than −30 mV, there is a tendency that chloride ions are difficult to enter even when a voltage is applied to the porous diaphragm. Furthermore, the zeta potential on the surface of the porous diaphragm can be greater than -15 mV.

  In an embodiment, a porous diaphragm can be disposed on the positive electrode side on the negative electrode.

  The porous diaphragm provided on the negative electrode can contain an inorganic oxide having a negative zeta potential in the region of pH 8 to 10. Thereby, the cation transport performance can be increased in the vicinity of the cathode in the weak alkali region. As such an inorganic oxide, an oxide whose zeta potential tends to be negative in an alkaline region can be used. Examples of such an inorganic oxide include zirconium oxide, titanium oxide, aluminum oxide, tungsten oxide, and zircon. , Silicon oxide, and zeolite can be used. As the inorganic oxide, a mixture of the above oxides can be used. Moreover, the abundance ratio of the inorganic oxide in the porous diaphragm can vary depending on the location. For example, there may be a region containing zirconium oxide having a high bending strength on the surface, and a region containing silicon oxide having a wide negative potential pH range inside.

  The porous membrane 24 of inorganic oxide can have irregular in-plane and three-dimensionally irregular pores by applying nanoparticles to form a membrane or by producing it with a sol-gel. In this case, the porous diaphragm 24 is resistant to bending and the like. In addition to the inorganic oxide, the porous diaphragm 24 may contain a polymer. The polymer gives the membrane flexibility. As such a polymer, a chemically stable main chain substituted with a halogen atom can be used, and examples thereof include polyvinylidene chloride, polyvinylidene fluoride, and Teflon (registered trademark). Among these, Teflon is preferable from the viewpoint of chemical and thermal stability. Examples of other polymers include hydrocarbon polymers such as polyethylene and polypropylene. Among these, polyethylene is preferable from the viewpoint of chemical stability and low cost. In addition, so-called engineering plastics such as polyimide, polysulfone, polyphenylene sulfide and the like can be used.

  The pore diameter of the porous diaphragm 24 can be different between the opening diameter on the first electrode 20 side and the opening diameter on the second electrode 22 side. By increasing the opening diameter of the hole on the second electrode 22 side, it is possible to make the movement of ions easier and reduce the stress concentration due to the through hole 40 of the first electrode 20. This is because the larger the opening on the electrode 22 side, the easier the ion movement by diffusion. Anions are attracted to the electrode relatively easily even if the hole diameter on the electrode 20 side is small. Conversely, if the pore diameter on the electrode 20 side is large, the generated chlorine or the like tends to diffuse to the porous diaphragm side.

  The pore diameter on the surface of the porous diaphragm can be measured by using a high-resolution scanning electron microscope (SEM). The internal holes can be measured by cross-sectional SEM observation.

  In FIG. 7, the schematic diagram showing an example of a structure of the electrode used for embodiment and a porous diaphragm is shown.

  As shown in the figure, the porous diaphragm 24 includes a first region 24 a that covers the first surface 21 a portion of the first electrode 20, and a second region that covers the openings of the plurality of first recesses 40 that communicate with the second hole 42. 24b. In the 21a portion, the generated gas such as chlorine is difficult to be discharged. Therefore, the electrode unit 12 tends to deteriorate. Therefore, in the porous diaphragm 24, the surface holes in the first region are eliminated, that is, formed to be non-porous, or the diameter of the surface holes in the first region 24a is made smaller than the diameter of the holes in the second region. Thus, it is possible to suppress the electrolytic reaction in the region in contact with the first region 24a and prevent the electrode unit 12 from deteriorating. In order to form pores or reduce the pore diameter, a thin nonporous membrane or a porous membrane having a small pore size can be 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 in the electrode region where gas tends to escape. Further, by covering the second surface 21b of the first electrode 20 on the side opposite to the porous diaphragm 24 with an electrically insulating film that does not allow liquid to permeate, it is possible to reduce side reactions. FIG. 7 also shows the first recess 40 that is not a through hole. As the porous diaphragm 24, a multilayer film in which a plurality of porous diaphragms having different pore diameters are stacked can be used. In this case, by making the pore diameter of the porous diaphragm located on the second electrode 22 side larger than the pore diameter of the porous diaphragm located on the first electrode 20 side, the movement of ions is facilitated and the electrode penetrates. Stress concentration due to holes can be reduced.

  The first electrode 20, the porous diaphragm 24, and the second electrode are pressed by pressing the porous diaphragm 24 between the first electrode 20 and the second electrode 22 configured as described above. 22 contacts, and the electrode unit 12 is obtained.

  As shown in FIG. 1, the electrode unit 12 is disposed in the electrolytic cell 11 and attached to the partition wall 14. The electrolytic cell 11 is partitioned into an anode chamber 16 and a cathode chamber 18 by the partition wall 14 and the electrode unit 12. Thereby, the electrode unit 12 is arrange | positioned in the electrolytic cell 11 so that the arrangement direction of a structural member may turn into a 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 electrolysis apparatus 10, both electrodes of the power supply 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 and 22 under the control of the control device 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 detection 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 detection information is supplied to the control device 36. The control device 36 controls the application of voltage or the load to the electrode unit 12 by the power supply 30 according to the detection information according to the program stored in the memory. The electrolyzer 10 applies an electric voltage or loads between the first electrode 20 and the second electrode 22 in a state in which the reaction target substance is supplied to the anode chamber 16 and the cathode chamber 18, and performs electrochemistry for electrolysis. Allow the reaction to proceed.

  As an example of forming the porous diaphragm 24 on the first surface 21a in which the catalyst 28 is formed on the surface of the first electrode 20, first, as shown in FIG. 6E, inorganic oxide particles and / or inorganic oxide precursors are formed. A solution containing the body is applied to the first surface 21a to prepare the pretreatment film 24c. Next, as shown in FIG. 6F, the pretreatment film 24c is sintered to produce a porous diaphragm 24 having porosity.

  As a method for producing a solution containing an inorganic oxide precursor, for example, a metal alkoxide is dissolved in alcohol, and a high-boiling solvent such as glycerin is added or sintered to produce a porous structure. A solution can be prepared by mixing organic substances such as fatty acids that easily oxidize into carbon dioxide. Moreover, in order to cover the porosity of an electrode, a solution can raise a viscosity by adding a small amount of water and hydrolyzing a metal alkoxide partially.

  As a method of forming 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 can be formed in advance on the first surface 21a of the first electrode 20, and the surface and pores can be covered with inorganic oxide particles and / or inorganic oxide precursors. Or the porous diaphragm which has an inorganic oxide can be formed on the holding body 25 holding an electrolyte solution by the said method. Moreover, these can be combined.

  As a method for applying a solution containing inorganic oxide particles and / or an inorganic oxide precursor, brush coating, spraying, dipping, or the like can be used. In the step of sintering the pretreatment film 24c to produce a porous material, the sintering temperature can be about 100 to 600 ° C.

  With the above configuration and manufacturing method, it is possible to provide a long-life electrode unit capable of maintaining stable electrolysis performance over a long period of time and an electrolysis apparatus using the electrode unit.

  Hereinafter, examples will be shown and embodiments will be described in detail.

Example (Example 1)
A flat titanium plate having a plate thickness T1 of 0.5 mm is prepared as the substrate 21 of the first electrode.

  The titanium plate is etched in the same manner as in the steps shown in FIGS. 6A to 6F to produce the first electrode 20 that can be used in the first embodiment. The electrode is 15 cm long in the water flow direction and 10 cm wide.

  Of the first electrode 20, the thickness of the region including the first recess 40 having a small area (the depth of the first recess) is 0.1 mm, and the thickness of the region including the second recess 42 having a large area (the second recess). Is 0.4 mm. The 1st recessed part 40 is a rhombus with a round corner as shown in FIG. 2A and 2B (the angle of the vertex of the extrapolated rhombus is 60 degrees and 120 degrees). The through hole is also a rhombus with rounded corners. The 2nd recessed part 42 is also a rhombus, and one side of a rhombus is about 3.6 mm.

The etched electrode substrate 21 is treated at 80 ° C. for 1 hour in a 10 wt% oxalic acid aqueous solution. Furthermore, it is anodized at 10 V for 2 hours in a mixed aqueous solution of 1M ammonium sulfate and 0.5M ammonium fluoride. Next, a solution prepared by adding 1-butanol to 0.25 M (Ir) to iridium chloride (IrCl ₃ .nH ₂ O) was applied to the first surface 21 a of the electrode substrate 21, and then dried. The catalyst layer 28 is formed by firing. In this case, drying is performed at 80 ° C. for 10 minutes, and baking is performed at 450 ° C. for 10 minutes. The electrode base material obtained by repeating application, drying, and firing of the iridium chloride butanol solution 5 times is referred to as a first electrode (anode) 20. The thickness of the catalyst layer is 2 μm.

  An aqueous dispersion mixture of titanium oxide fine particles having a particle diameter of 100 nm and polyvinylidene fluoride particles is applied to a glass cloth having 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 the atmosphere at 80 ° C. for 1 hour to create a porous diaphragm. The zeta potential at pH 4 on the porous diaphragm surface is -15 mV.

  Instead of creating the iridium oxide catalyst layer 28, the second electrode (counter electrode, cathode) 22 is formed in the same manner as the first electrode 21, except that platinum is sputtered as the catalyst layer. On top of that, a porous diaphragm 27 made of a titanium oxide film is produced in the same manner as the porous diaphragm 24. The thickness of the catalyst layer is 0.2 μm.

  As the holding body 25 for holding the electrolytic solution, porous polystyrene having a thickness of 5 mm is used. The first electrode 20, the porous diaphragm 24, the porous polystyrene 25, the porous diaphragm 27, and the second electrode 22 are overlaid and fixed using silicone packing and screws, and the electrode unit 12 is created. By placing the electrode unit 12 in the electrolytic cell 11, the partition 14 and the electrode unit 12 make the electrolytic cell 11, the anode chamber 16, the cathode chamber 18, and the porous polystyrene 25 disposed between the electrodes. It is divided into three chambers with the intermediate chamber 19 provided.

  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 straight channels are formed. A control device 36, a power source 30, a voltmeter 34, and an ammeter 32 are installed. A pipe 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 to secure the water supply lines 104 and 105. 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. A saturated saline tank 107 for circulating and supplying a saturated saline solution to the holder (porous polystyrene) 25 of the electrode unit 12, a pipe and a pump are connected to the electrode unit, and an electrolyte containing chloride ions is introduced into the electrolytic cell. A line L1 and a line 108 for collecting excess electrolyte are secured. As the water quality sensor 70, a conductivity sensor is installed at the outlet line of the acidic electrolyzed water, and a pH sensor is installed at the outlet line of the alkaline electrolyzed water. Thereby, an electrolyzer having the same configuration as that of FIG. 5 is obtained.

  Electrolysis is performed using the electrolyzer 10 at a flow rate of 2 L / min, a voltage of 5.7 V, and a current of 10 A. Hypochlorous acid water is supplied on the first electrode (anode) 20 side, and hydrogen is supplied on the second electrode (cathode) 22 side. And produces aqueous sodium hydroxide.

  No voltage increase is observed in the continuous operation of this device for 2000 hours.

  Thereafter, the electrodes were taken out, and the cross-sectional SEM was observed to calculate the curvature radii of the cross-sectional edges of the first concave portion and the second concave portion, and the average was 0.02 mm and 0.04 mm, respectively.

(Examples 2-6, Comparative Example 1)
Except for changing the mask pattern and etching conditions, an electrolytic electrode having a rhombus opening having a rounded corner or an elliptic opening is obtained in the same manner as in the first embodiment.

(Example 7)
A flat titanium plate having a plate thickness T1 of 0.5 mm is prepared as the substrate 21 of the first electrode.

  By etching the titanium plate in the same manner as in the steps shown in FIGS. 6A to 6F, the first electrode 20 that can be used in the electrolytic device of the embodiment can be produced. The electrode is 15 cm long in the water flow direction and 10 cm wide.

  Of the first electrode 20, the thickness of the region including the first recess 40 having a small area (the depth of the first recess) is 0.1 mm, and the thickness of the region including the second recess 42 having a large area (the second recess). Is 0.4 mm. As shown in FIG. 3A, the first recess 40 is a rectangle connected from end to end excluding the electrode seal portion, and the second recess 42 is also a rectangle connected from end to end excluding the electrode seal portion, It is orthogonal to the recess. The through hole is a rectangle with rounded ends as shown in FIG. 3B.

  An electrode unit and an electrolytic device are produced in the same manner as in Example 1 except that the first electrode and the second electrode produced in the same manner are used.

  Using this electrolyzer, electrolysis is performed at a flow rate of 2 L / min, a voltage of 6.2 V, and a current of 10 A. Hypochlorous acid water is supplied on the first electrode (anode) 20 side, and hydrogen is supplied on the second electrode (cathode) 22 side. And produces aqueous sodium hydroxide. No voltage increase is observed in the continuous operation of this device for 2000 hours. Thereafter, the electrode is taken out, and the curvature of the cross-sectional edge of the first recess is 0.03 mm on average by observation of the cross-sectional SEM.

(Examples 8 to 12, Comparative Example 2)
An electrode is obtained in the same manner as in Example 7 except that the mask pattern and etching conditions are changed. In the same manner as in Example 1, an electrode unit and an electrolyzer are prepared.

(Example 13)
A flat titanium plate having a plate thickness T1 of 1 mm is prepared as the substrate 21 of the first electrode.

  By etching the titanium plate in the same manner as in the steps shown in FIGS. 6A to 6F, the first electrode 20 that can be used in the electrolytic device of the embodiment can be produced. The electrode is 15 cm long in the water flow direction and 10 cm wide.

  Of the first electrode 20, the thickness of the region including the first concave portion 40 having a small area (depth of the first concave portion) is 0.4 mm, and the thickness of the region including the second concave portion 42 having a large area (second concave portion). Is 0.6 mm. As shown in FIG. 4A, the first recess 40 has a rounded end rectangle as shown in FIG. 4B.

  An electrode unit and an electrolytic device are produced in the same manner as in Example 1 except that the first electrode and the second electrode produced in the same manner are used.

  The through hole of the first electrode has a rounded end rectangle as shown in FIG. 4B. An electrode unit and an electrolysis apparatus are produced in the same manner as in Example 1 except that the first electrode and the second electrode are used.

  Using this electrolyzer, electrolysis was performed at a flow rate of 2 L / min, a voltage of 6.0 V, and a current of 10 A. Hypochlorous acid water was used on the first electrode (anode) side, hydrogen on the second electrode (cathode) 22 side, and hydrogen and Sodium hydroxide water is produced. In the continuous operation of this apparatus for 2000 hours, the voltage rise is 2%, and then the electrode is taken out, and the curvature of the cross-sectional edge of the first recess is 0.04 mm on average by observation of the cross-sectional SEM.

(Examples 14 to 15, Comparative Example 3)
An electrode is obtained in the same manner as in Example 13 except that the mask pattern and etching conditions are changed. In the same manner as in Example 1, an electrode unit and an electrolyzer are prepared.

(Example 16)
FIG. 8 schematically shows another example of the electrolysis apparatus according to the embodiment.

  As shown in FIG. 8, this electrolyzer 310 has a cathode chamber 318 and an anode chamber 316 arranged so as to surround the cathode chamber 318 instead of the electrolytic cell 11, and is free from natural convection without a channel and piping. The configuration is the same as that shown in 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 electrodes manufactured in the same manner as in Example 1 are used. However, the size of the electrode is 4 × 3 cm.

  Using this electrolyzer 310, electrolysis was performed at a voltage of 7V and a current of 2A for 5 minutes. Hypochlorous acid water was supplied on the first electrode (anode) side, and hydrogen and sodium hydroxide water were supplied on the second electrode (cathode) side. Generate. The electrolyzer 310 does not increase in voltage even after operating for a total of 2000 hours. Thereafter, the electrode is taken out, and the curvature of the cross-sectional edge of the first recess is 0.01 mm on average by observation of the cross-sectional SEM.

(Examples 17 to 21)
An electrode is obtained in the same manner as in Example 16 except that the mask pattern and etching conditions are changed. In the same manner as in Example 1, an electrode unit and an electrolyzer are prepared.

(Example 22)
FIG. 9 schematically shows another example of the electrolysis apparatus according to the embodiment.

  As shown in FIG. 9, the electrolyzer 310 has a porous membrane 29 as a spacer between the porous diaphragm 24 and the first electrode 20 in FIG. This porous film is the same as Example 16 except that a 76 μm thick glass cloth is used.

The electrolyzer 310 does not increase in voltage even after operating for a total of 2000 hours. Thereafter, the electrode is taken out, and the curvature of the cross-sectional edge of the first recess is 0.02 mm on average by observation of the cross-sectional SEM.

In Table 1 below, for Examples 1 to 22 and Comparative Examples 1 to 3, the curvature radius C1 (mm) of the edge of the first recess, the rate of voltage increase (%) after 2000 hours of operation, The curvature radius C2 (mm) of an edge part, the thickness of the catalyst layer of a 1st recessed part, and the cross-sectional area (mm < ² >) of a through-hole are shown.

  As shown in Table 1 above, when the edge curvature is 0.01 mm or more, the voltage increase after 2000 h operation is small or not seen. On the other hand, when it is larger than 2 mm in Examples 20 and 21, a reduction in initial hypochlorous acid production efficiency is observed.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 10 ... Electrolytic apparatus, 11 ... Electrolytic cell, 12 ... Electrode unit, 14 ... Partition, 16 ... Anode chamber, 18 ... Cathode chamber, 19 ... Intermediate chamber, 20, ... 1st electrode, 21, 23, ... Base material, 22 , ... 2nd electrode, 21a, 23a, ... 1st surface, 21b, 23b, ... 2nd surface, 24, 27 ... porous membrane, 25 ... holder, 26, 26a, 26b ... membrane, 28 ... catalyst layer, DESCRIPTION OF SYMBOLS 29 ... Porous film | membrane, 30 ... Power supply, 32 ... Ammeter, 34 ... Voltmeter, 40, 44, 61, 63 ... Through-hole (1st recessed part), 42, 46, 62 ... 2nd recessed part, 50 ... Resist film , 60 ... Bridge, 64 ... Voltage application port, 65 ... Beam, 70 ... Water quality sensor

Claims (20)

  A base having a first surface, a second surface facing the first surface, and a plurality of through holes penetrating from the first surface to the second surface, and a plurality of first recesses opening in the first surface And a plurality of second recesses that are open on the second surface and have an opening area larger than that of the first recess, and a radius of curvature of an edge portion of the opening of the first recess is 0.01 mm or more. And the electrode by which the catalyst layer was provided in the said 1st surface.   The electrode according to claim 1, wherein a radius of curvature of an edge portion of the opening of the first recess is 2 mm or less.   The electrode according to claim 1 or 2, wherein a radius of curvature of an edge portion of the opening of the second recess is 0.01 mm or more.   4. The electrode according to claim 1, wherein a part of the plurality of openings of the first recess penetrates a part of the second recess. 5.   5. The electrode according to claim 1, wherein a part of the region of the first recess penetrates a part of the second recess.   6. The electrode according to claim 1, wherein the number of the first recesses is greater than the number of the second recesses.   The electrode according to any one of claims 1 to 6, wherein the through hole has a rectangular shape with a round end at a minimum cross section in a direction parallel to the base material.   The electrode according to any one of claims 1 to 7, wherein the through-hole is a rhombus with an elliptical minimum section or a rounded corner in a direction parallel to the base material.   The electrode according to claim 1, wherein the second recess is connected from one end to the other end of the base material excluding a seal portion.   The electrode according to claim 1, wherein the first recess is connected from one end to the other end of the base material excluding a seal portion. The electrode according to any one of claims 1 to 10, wherein a minimum cross-sectional area of the through hole in a direction parallel to the base material is 0.01 to ⁴ mm2.   The electrode according to any one of claims 1 to 11, wherein the first surface has a flat region excluding the first recess. The electrode according to claim 12 , wherein an average roughness of the flat portion of the first surface is 0.01 μm to 3 μm.   14. The base material according to claim 1, wherein an opening ratio of a through hole located at a central portion of the base material is smaller than an opening ratio of a through hole located at a peripheral edge portion of the base material. Electrodes. A first electrode comprising the electrode according to any one of claims 1 to 14,
A porous membrane that transmits ions disposed on the first surface;
An electrode unit comprising: a second electrode provided on the first surface side of the first electrode; and an electrolyte solution holding structure provided between the porous diaphragm and the second electrode.   A porous membrane is provided between the first surface of the first electrode and the second electrode, and the porous membrane is formed between the first surface of the first electrode and the porous diaphragm. The electrode unit according to claim 15, which is sandwiched between the electrode units.   An electrolysis apparatus comprising: an electrolytic cell; and the electrode unit according to claim 15 or 16 incorporated in the electrolytic cell, a first electrode chamber partitioned by the electrode unit, and a second electrode chamber.   The first electrode chamber is an anode chamber, the second electrode chamber is a cathode chamber, a line for introducing an electrolytic solution containing chloride ions into the electrolytic cell, a line for extracting acidic electrolyzed water from the anode chamber, and The electrolyzer according to claim 17, further comprising a line for taking out alkaline electrolyzed water from the cathode chamber. The electrolysis apparatus according to claim 18 , wherein the line for taking out the acidic electrolyzed water further includes a sensor for measuring conductivity.   The electrolysis apparatus according to claim 17, wherein the first electrode chamber surrounds the second electrode chamber.

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