JPWO2017017977A1 - Electrode for electrolysis, electrode unit, and electrolysis apparatus - Google Patents

Abstract

The electrode for electrolysis according to the embodiment includes an electrode substrate having a plurality of through holes, a plurality of first recesses opened on the surface thereof, and a plurality of openings that are open on other surfaces and have a larger area and a smaller number than the first recesses. And the at least part of the through hole communicates the first and second recesses, and the minimum opening diameter passing through the center of the opening of each through hole is W, and the end of the opening diameter of one through hole F / W is 0.6 to 1.5 and F is 0.1 when the minimum distance is F among the distances from the end of the smallest opening diameter that passes through the center of the opening of the through hole adjacent to the portion. ~ 0.8 mm.

Description

  Embodiments described herein relate generally to an electrode for electrolysis, 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.

  In these electrolysis, high production efficiency of hypochlorous acid is necessary in the standing to produce hypochlorous acid. If the generation efficiency is low, a considerable part of the input electric power is consumed for oxygen gas generation or the like. Therefore, in order to obtain the required amount of hypochlorous acid, it is necessary to increase the current and voltage. This increases energy consumption and shortens the life of the electrolytic electrode and electrode unit.

JP 2014-101549 A JP 2013-194323 A

  An object of an embodiment of the present invention is to provide an electrolytic electrode, an electrode unit, and an electrolyzer having high hypochlorous acid production efficiency.

The electrode for electrolysis according to the embodiment includes a first surface, a second surface facing the first surface, an electrode base material having a plurality of through holes penetrating from the first surface to the second surface, Including a plurality of first recesses opening on one surface, and a plurality of second recesses opening on the second surface and having a larger opening area than the first recess,
At least a part of the through hole communicates the first recess and the second recess,
The first recess has a larger number than the second recess, and the minimum opening diameter passing through the center of the opening of the through hole is W, and the minimum passing through the center of the opening of the through hole adjacent to the end of the opening diameter When the minimum distance among the distances from the end of the opening diameter is F,
F / W is 0.6 or more and 1.5 or less, and F is 0.1 mm or more and 0.8 mm or less.

FIG. 1 is a diagram schematically illustrating an example of an electrolysis apparatus according to an embodiment. FIG. 2A is a diagram illustrating an example of an electrode having a diamond-shaped through hole with rounded corners according to the embodiment. FIG. 2B is a diagram illustrating an example of an electrode having a diamond-shaped through hole with rounded corners according to the embodiment. FIG. 3A is a diagram illustrating an example of an electrode having a rectangular through hole with a rounded end according to the embodiment. FIG. 3B is a diagram illustrating an example of an electrode having a rectangular through hole with a rounded end according to the embodiment. FIG. 4A is a diagram illustrating an example of an electrode having an elliptical through hole according to the embodiment. FIG. 4B is a diagram illustrating an example of an electrode having an elliptical through hole according to the embodiment. 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 electrodes and diaphragms used in the embodiment. FIG. 8 is a diagram illustrating an example of an electrode having a rectangular through hole with rounded ends according to the embodiment. FIG. 9 is a diagram illustrating an example of an electrode having a rectangular through hole with a rounded end according to the embodiment. FIG. 10 is a plot diagram showing the relationship between the electrode structure of the electrolysis apparatus according to the embodiment and the hypochlorous acid production efficiency. FIG. 11 is a diagram schematically illustrating an example of the electrolysis apparatus according to the embodiment. FIG. 12 is a diagram schematically illustrating an example of the electrolysis apparatus according to the embodiment.

  The electrode for electrolysis according to the embodiment is divided into the following first to third embodiments.

  The electrodes for electrolysis according to the first to third embodiments each have a first surface, a second surface facing the first surface, and a plurality of predetermined through holes penetrating from the first surface to the second surface. A single electrode substrate.

  The electrode for electrolysis according to the first embodiment includes a plurality of first recesses that open to the first surface, and a plurality of second recesses that open to the second surface and have a larger opening area than the first recess. In addition. Further, at least a part of the through hole communicates the first recess and the second recess, and the first recess has a larger number than the second recess. Furthermore, the predetermined plurality of through holes used in the first embodiment have a minimum opening diameter W passing through the center of the opening of each through hole, and are adjacent to the end of the opening diameter of one through hole. F / W is 0.6 or more and 1.5 or less, and F is 0.1 mm or more, where F is the minimum distance among the distances from the end of the smallest opening diameter that passes through the center of the opening of the hole. 0.8 mm or less.

  Moreover, the electrode for electrolysis according to the second embodiment has a rectangular through hole with a rounded end. Further, the predetermined plurality of through holes used in the second embodiment have a minimum opening diameter W passing through the center of the opening of each through hole, and are adjacent to the end of the opening diameter of one through hole. F / W is 0.6 or more and 1.5 or less, where F is the minimum distance among the distances from the end of the smallest opening diameter that passes through the center of the opening of the hole.

  Furthermore, the electrode for electrolysis according to the third embodiment includes a recess provided on the first surface and connected from one end to the other end of the electrode excluding the seal portion, and at least a part of the through hole communicates with the recess. Furthermore, the predetermined plurality of through-holes used in the third embodiment have a minimum opening diameter W passing through the center of the opening of each through-hole, and an end portion of the opening diameter of one through-hole. F / W is 0.6 or more and 1.5 or less, where F is the minimum distance among the distances from the end portion of the minimum opening diameter that passes through the center of the opening of the adjacent through hole.

  Note that a single electrode substrate is formed by processing a single substrate, unlike a bonded substrate.

  The configurations of the first to third embodiments described above can be combined as necessary.

  An electrode unit according to an embodiment is an electrode unit using the above-described electrode for electrolysis as a first electrode, and is disposed so as to face a first electrode having a first surface and a second surface, and the first surface of the first electrode. And a second electrode, a diaphragm provided on the first surface of the first electrode, and an electrolyte solution holding structure provided between the diaphragm and the second electrode.

  An electrolysis apparatus according to the embodiment is an example of an electrolysis apparatus to which the above-described electrolysis electrode and an electrode unit using the electrolysis electrode 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 that monitors water quality can be optionally installed in the line. For example, a conductivity sensor and / or a pH sensor can be applied to a line for extracting acidic electrolyzed water. Further, a pH sensor and / or a sodium ion sensor can be applied to a line for taking out alkaline electrolyzed water. A conductivity sensor that can measure about 0 to 20 mS / cm can be used. When such a conductive sensor is used, it can be detected when a small amount of ionic impurities are mixed in the acidic electrolyzed water.

  Further, according to the first embodiment, the minimum opening diameter W passing through the center of the opening of the through hole, and the end of the minimum opening diameter passing through the center of the opening of the through hole adjacent to the end of the opening diameter, The relationship between F / W and the range of F with respect to the minimum distance F is defined as described above, and there are a plurality of first recesses that open on the first surface and openings on the second surface. By further including a plurality of second recesses having an opening area larger than that of the first recesses, hypochlorous acid production efficiency can be increased.

  Furthermore, according to the second embodiment, since the end is a round rectangular through hole, W can be reduced and F and W can be made constant over a long distance even if the opening area is increased. The uniformity of the reaction can be further improved. The generation efficiency of hypochlorous acid can be increased as with the electrode for electrolysis of the first embodiment. In addition, this structure is simple and can increase the yield. In particular, when W is large and the electrode substrate is thin, it can be produced by one-side etching, so that the production efficiency of hypochlorous acid is somewhat reduced, but it can be produced at low cost. Further, when the electrode substrate is thick, the both-side etching is more efficient than the one-side etching because of the speed, and when W is large, the pattern tends to be easily matched.

  Furthermore, according to the third embodiment, when the concave portion connected to the other end of the electrode excluding the seal portion is formed on the first surface, a slight gap is formed between the diaphragm and the first surface of the electrode. Thus, the retention of chloride ions and the discharge of hypochlorous acid are facilitated, and the uniformity of the reaction in the entire electrode is easily ensured. On the other hand, if the concave portion connected to the other end of the electrode excluding the seal portion is formed on the second surface, the effect of the external water flow tends to be uniform over the entire electrode. The uniformity of the reaction is improved. The generation efficiency of hypochlorous acid can be increased as with the electrode for electrolysis of the first embodiment.

  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 showing an example of the electrolysis apparatus according to the first 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 a diaphragm 24 is provided thereon. Another 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 an intermediate chamber (electrolyte chamber) 19 that holds the electrolyte is formed between the 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 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 diaphragm 24 side is smaller than the opening diameter R2 of the second recess 42, and the number of recesses is such that the first recess 40 is larger than the second recess 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 side of the diaphragm 24 is smaller than the opening diameter R2 of the second recess 42, and the number of recesses is such that the first recess 40 is formed more than the second recess 42. The stress due to the edge of the concave portion is relaxed and the life of the diaphragm 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 and 2B 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 a cross section where the cross-sectional area of the through hole is small.

  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.

  Further, in the first electrode 20 having a porous structure, by forming the through hole with a tapered surface or a curved surface where the opening on the first surface side becomes wide, the contact angle between the opening of the through hole and the diaphragm 24 becomes an obtuse angle, Stress concentration on the diaphragm 24 can also be reduced. Thereby, the opening of the through hole is smaller than the opening of the first recess 40 on the first surface 21a.

  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, current concentration can be prevented, and the curvature can be 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, gas can be easily released. 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. The minimum opening diameter passing through the center of the opening of the through hole is W, and the minimum distance among the distances between the end of the opening diameter and the end of the minimum opening diameter passing through the center of the opening of the adjacent through hole is F. Then, F / W is 0.6 or more and 1.5 or less, and F is 0.1 mm or more and 0.8 mm or less. Here, the center is the center of gravity of the opening shape.

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 diaphragm side, accumulate in 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.

  According to the embodiment, the minimum opening diameter passing through the center of the opening of the through hole is W, and the distance between the end of the opening diameter and the end of the minimum opening diameter passing through the center of the opening of the adjacent through hole is When F / W is 0.6 or more and 1.5 or less and F is 0.1 mm or more and 0.8 mm or less, the chloride ion concentration can be increased. Here, the distance between the minimum opening diameter W passing through the center (center of gravity) of the opening of the through hole and the end of the minimum opening diameter passing through the center of the opening of the adjacent through hole is above the opening diameter. By using the minimum combination of W and F at the minimum distance F, the most effective diffusion can be obtained. Since the amount of transmission of chloride ions also becomes a problem, the opening diameter passing through the center of gravity that affects the amount of transmission is assumed to be W.

  Since positive is applied to the positive electrode, there is an effect that chloride ions are attracted to the electrode, and the concentration of chloride ions can be increased even if F / W is 0.6 and the ratio of W is relatively large. However, when F / W is smaller than 0.6 or when F is smaller than 0.1 mm, it is difficult to increase the chloride ion concentration by shielding with an electrode.

  When F / W is larger than 1.5 or when F is larger than 0.8 mm as in the first embodiment, the generated hypochlorous acid is discharged from the through hole to the outside through the second recess. It becomes difficult to discharge, and reverse diffusion to the diaphragm side or reaction that reacts with protons to generate chlorine gas tends to occur. When F / W is large, the aperture ratio tends to be small, but the relationship between the aperture ratio and hypochlorous acid production efficiency is small. The electrode of the first embodiment preferably has an F / W of 0.7 to 1.4 and F of 0.15 mm to 0.6 mm, and more preferably an F / W of 0.9 to 1 .3 or less and F is 0.2 mm or more and 0.4 mm or less.

  Although many through holes exist in the electrode, it is preferable that the through holes having F / W of 0.6 or more and 1.5 or less and F of 0.1 mm or more and 0.8 mm or less are 80% or more. More preferably, it is 85% or more, More preferably, it is 90% or more.

  In the electrodes of the second and third embodiments, the F / W can be preferably 0.7 or more and 1.4 or less. More preferably, it can be 0.9 or more and 1.3 or less. Moreover, F can be 0.1 mm or more and 2.5 mm or less. More preferably, F can be 0.2 mm or more and 1.5 mm or less, and further preferably 0.3 mm or more and 1 mm or less.

  Although many through holes exist in the electrode, it is preferable that the through holes having F / W of 0.6 to 1.5 are 80% or more. More preferably, it is 85% or more, More preferably, it is 90% or more.

  FIG. 3A schematically shows an exploded perspective view showing an example of an electrode unit to which the electrodes according to the first to third embodiments can be applied.

  FIG. 3B is a diagram illustrating an example of the shape of the through hole used in the embodiment.

  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.

   In the first embodiment and the third embodiment, any shape is possible as the shape of the through hole, but the end as shown in FIG. 3B corresponding to the second embodiment is a round rectangle or an ellipse. Or a rhombus with rounded corners is preferred. FIG. 3A shows a part of the electrode. In such a shape, since the end is round, stress concentration with respect to the diaphragm hardly occurs. Further, if the opening interval can be made dense, the opening ratio can be increased. The outline of the shape of the through hole may be uneven. Moreover, the end may be a group of a plurality of arcs having different diameters.

  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 diaphragm side, resulting in a 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 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 of the second recess 42 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 42 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 recess 63 can be various shapes such as a square, a rectangle, a rhombus, a circle, an ellipse, and the like. 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.

  FIG. 4A schematically shows an exploded perspective view showing another example of the electrode unit using the electrode according to the third embodiment.

  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.

  FIG. 4B shows a diagram illustrating another example of the shape of the through hole used in the embodiment.

  As illustrated, in the electrode 221 'and the electrode 223', the first recess 61 'constituting the through hole has an elliptical shape. In addition, two recesses, that is, the first recess 62 ′ and the second recess 63 that are connected from end to end of the electrode excluding the seal portion are parallel to each other.

  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, by forming a through hole with a tapered surface or a curved surface where the opening on the first surface side is widened, the contact angle with the diaphragm 24 with the opening of the through hole becomes an obtuse angle to the diaphragm 24. It is also possible to reduce the stress concentration.

  The first recess 40 only needs to communicate at least partially with the second recess 42, and can include the first recess 40 that is not the through hole 43. The first recess 40 that is not in communication has the effect of increasing the electrode area and the effect of promoting the retention and diffusion of the substance.

  The radius of curvature of the edge of the cross section excluding the catalyst layer on the first surface of the through hole is preferably 0.01 mm or more. Thereby, the current concentration at the edge portion can be relaxed and the catalyst layer can be formed uniformly. If it is smaller than 0.01 mm, the 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.

  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 manufacturing the first electrode 20 and the diaphragm 24 having the above-described configuration will be described below.

  6A to 6F are views showing an example of a method for manufacturing the electrode unit 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 and the shape of the curved surface 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. Further, the first electrode 20 can be manufactured not only by etching but also by an expanding method, a punching method, or processing by laser or precision cutting, but the etching method is most preferable.

  As the base material 21 of the first electrode 20 used in the first to third embodiments, a valve metal such as titanium, chromium, aluminum or an alloy thereof, or a conductive metal can be used. Of 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, 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.

  A first catalyst layer made of an electrocatalyst provided between the first electrode and the first diaphragm, and a surface of the first electrode opposite to the first catalyst layer; May further include second catalyst layers having different amounts 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.

  It is preferable that the surface (first surface) on the diaphragm 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 actual surface area of the electrode tends to decrease, and if it is larger than 3 μm, stress on the 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.

  For example, the diaphragm 24 is formed in a rectangular shape having substantially the same dimensions as the first electrode 20 and faces the entire surface of the first surface 21a. The 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.

  A porous diaphragm can be used as the diaphragms 24 and 27. Furthermore, 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 diaphragm, an ion-selective membrane such as a hydrocarbon polymer ion permeable membrane or a fluorine polymer ion permeable membrane can be used.

  The diaphragm preferably contains an inorganic oxide. In particular, the positive electrode side diaphragm is preferably an inorganic oxide having a positive zeta potential in a pH range of 2 to 6. Thereby, the transport performance of the diaphragm 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 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 diaphragm may further include two or more different oxides, and the abundance ratio of each oxide may vary depending on the position of the diaphragm. For example, a region containing zirconium oxide having a high bending strength exists on the surface, and a region containing aluminum oxide or titanium oxide having a large absolute value of a positive potential can exist inside.

  The zeta potential on the surface of the diaphragm can be greater than −30 mV at pH 4. If it is smaller than −30 mV, chloride ions tend to hardly enter even when a voltage is applied to the diaphragm. Furthermore, the zeta potential on the surface of the diaphragm can be greater than -15 mV.

  In the embodiment, the diaphragm can be arranged on the positive electrode side on the negative electrode.

  The 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 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 inorganic oxide diaphragm 24 can have pores irregularly in-plane and three-dimensionally, by applying nanoparticles to form a film, or by producing it with a sol-gel. In this case, the diaphragm 24 is resistant to bending and the like. The diaphragm 24 may contain a polymer in addition to the inorganic oxide. 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. Also, so-called engineering plastics such as polyimide, polysulfone, polyphenylene sulfide and the like can be used.

  The opening diameter of the diaphragm 24 can be different from 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 hole diameter on the electrode 20 side is large, the generated chlorine or the like tends to diffuse to the diaphragm side.

  The pore diameter on the surface of the 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 and diaphragm used for embodiment is shown.

  As shown in the drawing, the 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 24 b that covers the openings of the plurality of first recesses 40 that communicate with the second hole 42. ,have. 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 diaphragm 24, the surface holes in the first region are eliminated, that is, formed without holes, 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, The electrolytic reaction in the region in contact with the first region 24a can be suppressed, and deterioration of the electrode unit 12 can be prevented. In order to reduce the hole diameter or to make the hole non-porous, a thin non-porous film or a small-diameter diaphragm 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 opposite to the diaphragm 24 with an electrically insulating film that does not allow liquid to pass through, it is possible to reduce side reactions. FIG. 7 also shows the first recess 40 that is not a through hole. As the diaphragm 24, a multilayer film in which a plurality of diaphragms having different pore diameters are stacked can be used. In this case, by making the hole diameter of the diaphragm located on the second electrode 22 side larger than the hole diameter of the diaphragm located on the first electrode 20 side, it is easier to move ions and stress concentration due to the through holes of the electrode. Can be reduced.

  By pressing the diaphragm 24 between the first electrode 20 and the second electrode 22 configured as described above, the first electrode 20, the diaphragm 24, and the second electrode 22 are in contact with each other. 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 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 used. The pre-treatment film 24c is prepared by applying the solution containing the first surface 21a. Next, as shown in FIG. 6F, the pretreatment film 24c is sintered to produce a porous diaphragm 24.

  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 diaphragm 24, another porous film, for example, porous Teflon, which is a porous polymer, porous polyethylene, porous vinylidene fluoride, etc., porous glass which is a porous ceramic, porous quartz, porous A solution containing inorganic oxide particles and / or an inorganic oxide precursor can be applied to a porous zeolite or the like. 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 diaphragm which has an inorganic oxide can be formed on the holding body 25 which hold | maintains 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 high-efficiency 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 first recessed hole portion 40 has a rounded diamond shape as shown in FIGS. 2A and 2B (the apex angles of the extrapolated rhombus are 60 ° and 120 °). 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. An electrode base material obtained by repeating such coating, drying, and firing five times is referred to as a first electrode (anode) 20. F / W is 0.75 and F is 0.2 mm.

  As a diaphragm, 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 and dried. Furthermore, it is immersed in a 5% isopropanol solution of tetraisopropoxyzirconium (IV) and pulled up to the atmosphere. Dry in the air at 80 ° C. for 1 hour to make a diaphragm. The zeta potential of this diaphragm surface at pH 4 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 diaphragm 27 having a titanium oxide film is produced in the same manner as the diaphragm 24.

  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 diaphragm 24, the porous polystyrene 25, the diaphragm 27, and the second electrode 22 are overlaid and fixed using silicone packing and screws, and the electrode unit 12 is created. The electrode unit 12 is placed in the electrolytic cell 11, and the partition wall 14 and the electrode unit 12 are used to form an anode chamber 16, a cathode chamber 18, and an intermediate chamber 19 provided with a porous polystyrene 25 disposed between the electrodes. 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 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. The production efficiency of hypochlorous acid is 73%. Here, the production efficiency of hypochlorous acid is obtained from the amount of charge charged by measuring the effective chlorine concentration of the treated water.

(Examples 2-15, Comparative Examples 1-4)
Except for changing the mask pattern so that F and F / W are as shown in Table 1 below, an electrolytic electrode having a rhombus with a rounded corner or an elliptical opening is obtained in the same manner as in Example 1. . Moreover, hypochlorous acid production | generation efficiency was computed by measuring the cross-sectional area of a through-hole, and measuring the effective chlorine concentration of a treated water, and it shows in following Table 1.

(Example 16)
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 the steps shown in FIGS. 6A to 6F, the first electrode 20 that can be used in the electrolyzer according to the first to third embodiments can be manufactured. 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 concave hole 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 first recess. The through hole is a rectangle with rounded ends as shown in FIG. 3B.

  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 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. The production efficiency of hypochlorous acid is 75%.

  The cross-sectional area of the through-hole is measured and shown in Table 2 below together with the efficiency of hypochlorous acid production.

(Examples 17-30, Comparative Examples 5-8)
An electrode for electrolysis is obtained in the same manner as in Example 16 except that the mask pattern is changed so that F and F / W are as shown in Table 2 below. In the same manner as in Example 1, an electrode unit and an electrolytic device are prepared.

In Example 24, the first recess and the second recess are parallel. Table 2 below shows the hypochlorous acid production efficiency calculated by measuring the cross-sectional area of the through-holes and measuring the effective chlorine concentration of the treated water.

(Example 31)
A flat titanium plate having a plate thickness T1 of 0.4 mm is prepared as the substrate 221 '' of the first electrode.

  The titanium plate is etched, but the first and second electrodes 220 ″ and 222 ″ of the second embodiment shown in FIG. 8 are manufactured only by etching from one side. Each electrode 220 ″, 222 ″ has a length of 15 cm in the water flow direction and a width of 10 cm.

The through-holes 61 '' of the first electrode 221 '' are rectangular with round ends as shown in FIG. 3B, and are arranged in a direction in which the length in the water flow direction is larger than the width, that is, in series. The cross section of the penetrating term is tapered, and the area of the through hole 61 ″ on the first surface on the porous membrane side is wider than the second surface 221b ″ on the flow path side. Similarly, in the second electrode 222 '', the area of the first surface 223a '' of the through hole 61 '' is wider than the second surface on the flow path side.
The direction of the thick beam or the wide beam 65 ″ in which the through holes 61 ″ are arranged in series and separate the rows of the through holes is the direction of the voltage application port of the electrode.

  Except for using the first electrode and the second electrode, the electrode unit 212 ″ and the electrolysis apparatus are produced in the same manner as in the first embodiment.

  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. The production efficiency of hypochlorous acid is 62%.

(Examples 32-37, Comparative Examples 10-11)
An electrode for electrolysis is obtained in the same manner as in Example 31 except that the mask pattern is changed so that F and F / W are as shown in Table 3 below.

  However, Example 37 produces and uses the 1st and 2nd electrode of 2nd Embodiment shown in FIG. A titanium plate having a thickness of 1 mm is prepared by etching on both sides. As shown in the drawing, the through holes 61 ′ ″ of the first electrode 221 ′ ″ and the second electrode 223 ′ ″ have a rectangular shape with a round end as shown in FIG. 3B, and have a length perpendicular to the water flow direction. They are arranged in a direction larger than the width, that is, in parallel. The cross-section of the penetrating term is a tapered shape with a wide surface, and the inside is narrow.

  Except for using the first electrode and the second electrode described above, an electrode unit 212 ″ ″ and an electrolysis device are produced in the same manner as in the first embodiment.

Table 3 below shows the hypochlorous acid production efficiency calculated by measuring the cross-sectional area of the through-holes and measuring the effective chlorine concentration of the treated water.

(Example 38)
A flat titanium plate having a plate thickness T1 of 1 mm is prepared as the substrate 21 of the first electrode.

  This titanium plate is etched and punched from both sides to produce the first electrode of the third embodiment shown in FIG. 4A. The electrode is 15 cm long in the water flow direction and 10 cm wide.

  The through hole of the first electrode is an ellipse in FIG. 4B. A rectangular groove is formed by etching, and an elliptical opening is formed by punching.

  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. The production efficiency of hypochlorous acid is 70%.

(Example 39, Comparative Examples 12-13)
An electrode for electrolysis is obtained in the same manner as in Example 38 except that the pattern is changed so that F and F / W are as shown in Table 4 below.

Table 4 below shows the hypochlorous acid production efficiency calculated by measuring the cross-sectional area of the through-hole and measuring the effective chlorine concentration of the treated water.

  In FIG. 10, the plot figure showing the relationship between F / W value and hypochlorous acid production | generation efficiency is shown.

  This plot was created by plotting the results of Table 1, Table 2, Table 3, and Table 4 with ◆, □, Δ, and X, respectively. In an Example, the hypochlorous acid production | generation efficiency of 60% or more is obtained.

  In the figure, when the F / W is outside the range of 0.6 to 1.5, sufficient hypochlorous acid production efficiency cannot be obtained. As indicated by *, in Tables 1 and 2, when F is outside the range of 0.1 to 0.8 mm, sufficient hypochlorous acid production efficiency cannot be obtained. In the embodiment of Table 3, the production efficiency of hypochlorous acid is somewhat lowered, but can be produced at a low cost.

(Example 40)
FIG. 11 is a diagram schematically illustrating another example of the electrolysis apparatus according to the embodiment.

  As shown in FIG. 11, this electrolysis apparatus 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 16 are used. However, the size of the electrode is 4 × 3 cm.

  Electrolysis is performed at a voltage of 7 V and a current of 2 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. The production efficiency of hypochlorous acid is 80%.

(Example 41)
FIG. 12 schematically shows another example of the electrolysis apparatus according to the embodiment.

  As shown in FIG. 12, 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 40 except that a glass cloth having a thickness of 76 μm is used.

 Electrolysis is performed at a voltage of 7.2 V and a current of 2 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. The production efficiency of hypochlorous acid is 82%.

  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 ... diaphragm, 25 ... holder, 26, 26a, 26b ... diaphragm, 28 ... catalyst layer, 29 ... Porous membrane, 30 ... power source, 32 ... ammeter, 34 ... voltmeter, 40, 44, 61, 63 ... through hole (first recess), 42, 46, 62 ... second recess, 50 ... resist film, 60 ... Bridge, 64 ... Voltage application port, 65 ... Beam, 70 ... Water quality sensor

The electrode for electrolysis according to the embodiment includes a first surface, a second surface facing the first surface, an electrode base material having a plurality of through holes penetrating from the first surface to the second surface, Including a plurality of first recesses opening on one surface, and a plurality of second recesses opening on the second surface and having a larger opening area than the first recess,
At least a part of the through hole communicates the first recess and the second recess,
The through hole has a wide opening on the first surface side,
The first recess has a larger number than the second recess, and the minimum opening diameter passing through the center of the opening of the through hole is W, and the minimum passing through the center of the opening of the through hole adjacent to the end of the opening diameter When the minimum distance among the distances from the end of the opening diameter is F,
F / W is 0.6 or more and 1.5 or less, and F is 0.1 mm or more and 0.8 mm or less.

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.

As illustrated, in the electrode 220 ′ and the electrode 222 ′, the opening 61 ′ constituting the through hole has an elliptical shape. In addition, two recesses, that is, the first recesses 62 ′ and the second recesses 63 that are connected from end to end of the electrode excluding the seal portion are parallel to each other.

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

  In addition, the 1st recessed part should just have the 1st recessed part which is not a through-hole as long as at least one part communicates the 2nd recessed part. The first recess that is not in communication has the effect of increasing the electrode area and the effect of promoting the retention and diffusion of the substance.

Claims (20)

A first surface, a second surface opposite to the first surface, and an electrode substrate having a plurality of through holes penetrating from the first surface to the second surface, and a plurality of firsts opening to the first surface Including a recess, and a plurality of second recesses that are open in the second surface and have a larger opening area than the first recess,
At least a part of the through hole communicates the first recess and the second recess,
The first recess has a larger number than the second recess, and the minimum opening diameter passing through the center of the opening of the through hole is W, and the minimum passing through the center of the opening of the through hole adjacent to the end of the opening diameter When the minimum distance among the distances from the end of the opening diameter is F,
An electrode for electrolysis in which F / W is 0.6 or more and 1.5 or less and F is 0.1 mm or more and 0.8 mm or less.   The electrode for electrolysis according to claim 1, wherein the through hole has a rectangular shape with a round end.   The electrode for electrolysis according to claim 1, wherein the through hole has an ellipse or a rhombus with rounded corners. The second recess of the opening, the electrode for electrolysis according to any one of claims 1 to 3 having an area of 1～1600Mm ^2.   5. The electrode for electrolysis according to claim 1, wherein the first concave portion has a peripheral wall having a tapered surface shape or a curved surface shape in which the first surface side is widened.   The electrode for electrolysis according to any one of claims 1 to 5, wherein the second recess is connected from one end to the other end of the electrode base material excluding a seal portion.   The electrode for electrolysis according to claim 1, wherein the first recess is connected from one end to the other end of the electrode base material excluding a seal portion.   The electrode for electrolysis according to any one of claims 1 to 7, wherein the first recess and the second recess are orthogonal to each other.   The electrode for electrolysis according to any one of claims 1 to 7, wherein the first recess and the second recess are parallel to each other. An electrode substrate 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;
The through hole is a rectangle with rounded ends,
The minimum opening diameter passing through the center of the opening of the through hole is W, and the minimum distance among the distances between the end of the opening diameter and the end of the minimum opening diameter passing through the center of the opening of the adjacent through hole Is F,
Electrode for electrolysis whose F / W is 0.6 or more and 1.5 or less. An electrode base material 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;
A concave portion provided on the first surface and connected to the other end of the electrode base material excluding the seal portion;
At least a portion of the through hole communicates with the recess,
The minimum opening diameter passing through the center of the opening of the through hole is W, and the minimum distance among the distances between the end of the opening diameter and the end of the minimum opening diameter passing through the center of the opening of the adjacent through hole Is F,
Electrode for electrolysis whose F / W is 0.6 or more and 1.5 or less.   The electrode for electrolysis according to claim 10 or 11, wherein the F is 0.1 mm or more and 2.5 mm or less.   The electrode for electrolysis according to any one of claims 1 to 12, wherein a region excluding the concave portion is formed flat on the first surface.   14. The aperture ratio of a through hole located in the central portion of the electrode base material among the plurality of through holes is different from the aperture ratio of a through hole located in a peripheral edge portion of the electrode base material. The electrode for electrolysis of Claim 1.   The electrode for electrolysis according to any one of claims 1 to 14, wherein the first surface is anodized.   The electrode for electrolysis according to any one of claims 1 to 15, wherein the through holes are arranged in series, and a direction of a thick beam or a wide beam separating rows of the through holes is a direction of a voltage application port of the electrode. . A first electrode comprising the electrode for electrolysis according to any one of claims 1 to 16,
A diaphragm 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 diaphragm and the second electrode.   A porous film provided between the first surface of the first electrode and the second electrode and transmitting at least one of ions and liquid; the porous film being a first electrode of the first electrode; The electrode unit according to claim 17, which is sandwiched between a surface and the diaphragm.   An electrolysis apparatus comprising: an electrolytic cell; and the electrode unit according to claim 17 or 18 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 electrolysis apparatus according to claim 19, further comprising a line for taking out alkaline electrolyzed water from the cathode chamber.

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