JPWO2016125333A1 - Electrode unit and electrolysis apparatus using the same - Google Patents

Abstract

The electrode unit according to the embodiment includes a first electrode, a second electrode provided to face the first electrode, and a porous membrane disposed on the second electrode side on the first electrode. The first electrode includes a plurality of first recesses that are open on the first surface, and a plurality of second recesses that are open on a second surface that is located behind the first surface and have a larger opening area than the first recess. And having a plurality of through-holes communicating the first recess and the second recess. The through hole has a curved portion and a straight portion, and the curvature radius r of the curved portion is from 0.005 mm to 0.5 mm, and the opening area is from 0.05 mm2 to 2 mm2.

Description

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

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

  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, hypochlorite water, hydrochloric acid 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, gases such as chlorine, hydrogen and oxygen are generated. For this reason, the larger the hole of the electrode having a circular or elliptical porosity, the easier the gas escapes. However, if the hole is large, the space between the holes is narrowed, resulting in an increase in electrical resistance, resulting in low energy efficiency and heat generation. On the other hand, square and rhombus openings are also known, but in this case, stress is likely to concentrate at the corners of the edges, and the ion exchange membrane that is in contact with it is scratched. Affects.

JP 2014-101549 A JP 2013-194323 A

  The subject of embodiment of this invention is providing the electrode unit and electrolyzer which can be driven stably for a long time.

According to the embodiment, the electrode unit has a first surface, a second surface located behind the first surface, a plurality of first recesses opened in the first surface, and an opening in the second surface. And a first electrode having a plurality of second recesses having an opening area larger than that of the first recess, a plurality of through holes communicating the first recess and the second recess, and a first surface of the first electrode. In the electrolysis unit comprising the second electrode provided as described above and the porous diaphragm disposed on the second electrode side on the first electrode, the through hole has a curved portion and a straight portion, The radius of curvature r is from 0.005 mm to 0.5 mm, and the opening area is from 0.05 mm ² to 2 mm ² .

It is a figure showing roughly an example of an electrolysis device concerning an embodiment. It is a schematic diagram for demonstrating the through-hole of FIG. It is a disassembled perspective view of the electrode unit which concerns on embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a mimetic diagram showing an example of composition of an electrode used for an embodiment, and a porous diaphragm. It is a figure which represents typically the 2nd surface of the electrode used for embodiment. It is a disassembled perspective view of the modification of the electrode unit for hypochlorous acid water production which can be used for embodiment. It is a disassembled perspective view of the modification of the electrode unit for hypochlorous acid water production which can be used for embodiment. It is a disassembled perspective view of the modification of the electrode unit for hypochlorous acid water production which can be used for embodiment. It is a figure showing roughly an example of an electrolysis device concerning an embodiment. It is a figure which shows roughly another example of the electrolysis apparatus which concerns on embodiment. It is a disassembled perspective view which shows an example of the electrode unit concerning embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a figure showing an example of the manufacturing method of the electrode unit concerning an embodiment. It is a schematic diagram showing the position of each area | region of a 1st electrode. It is another example of the electrode unit concerning embodiment. It is a figure which shows roughly another example of the electrolysis apparatus which concerns on embodiment. It is a further another example of the electrode unit concerning embodiment.

  Below, the electrode unit and electrolyzer which concern on embodiment are demonstrated.

  The electrode unit according to the embodiment includes a first electrode, a second electrode provided to face the first electrode, and a porous membrane disposed on the second electrode side of the first electrode.

  The first electrode is open to the first surface facing the second electrode, the second surface located on the opposite side of the first surface, a plurality of first recesses opened to the first surface, and the second surface. A plurality of second recesses having an opening area larger than that of the first recess, and a plurality of through-holes communicating the first recess and the second recess.

The through hole includes a curved portion and a straight portion, and the curvature radius r of the curved portion is from 0.005 mm to 0.5 mm, and the opening area is from 0.05 mm ² to 2 mm ² .

  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 located in the anode chamber 16, a second electrode (counter electrode) 22 located in the cathode chamber 18, and a catalyst layer 28 on the first surface 21 a of the first electrode 20. Formed and having a porous diaphragm 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. A liquid channel may be provided in the anode chamber 16 and the cathode chamber 18. You may connect the anode chamber 16 and the cathode chamber 18 with piping, a pump, etc. for supplying and discharging a liquid from the outside. In some cases, a porous spacer may be provided between the electrode unit 12 and the anode chamber 16 or the cathode chamber 18.

  As shown in FIG. 1, the 1st electrode 20 has the porous structure which formed many through-holes in the base material 21 which consists of a rectangular metal plate, for example. 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.

  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, and the opening area of the first recess is smaller than the opening area of the second recess. Further, the number of the recesses is 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 this embodiment, for example, T2 <T3. In FIG. 1, the first recess 40 communicates with the second recess and forms a through hole 43.

The through-hole 43 has a curved portion and a straight portion, the curvature radius r of the curved portion is 0.005 mm to 0.5 mm, and the opening area is 0.05 mm ² to 2 mm ^2. Yes.

  In FIG. 1, the second electrode is shown with the same opening structure (mirror image) as the first electrode, but may be different.

  FIG. 2 is a schematic diagram for explaining the through hole 43 of FIG.

As shown in the drawing, the through hole 43 has, for example, a rounded rectangular shape including a rounded corner portion R and a straight portion L as a bent portion. The plurality of through holes are provided in a matrix on the first surface 21a. The current is supplied to the first electrode 20 from the periphery of the electrode, but the electric resistance is determined by the narrowest width W0 of the electrode portion sandwiched between the hole portions 43. The smaller W0, the higher the electrical resistance. As a result, the drive voltage increases, and heat generation and current concentration are likely to occur. Even if W0 is the same, the rectangular area can be larger than the circular or elliptical shape. Therefore, it becomes advantageous for discharge of hypochlorous acid and gas. In addition, when the corners of the rectangle are rounded, stress is more likely to be concentrated than when the corners of the rectangle are rounded, and the porous film in contact with the electrode is likely to be damaged. Furthermore, if the rectangular corners are rounded, current concentration tends to occur and electrolysis tends to be non-uniform, and the life of the apparatus is shortened due to deterioration of the catalyst. In order to prevent such a situation, the radius of curvature r of the curved portion needs to be 0.005 mm to 0.5 mm. If the radius is smaller than 0.005 mm, there is no effect, and if it is larger than 0.5 mm, the chloride ion shielding effect is obtained. The production efficiency of hypochlorous acid is reduced. The curvature radius r of the bent portion is more preferably 0.01 mm to 0.3 mm, and further preferably 0.02 mm to 0.2 mm. In order to increase the aperture ratio of the through hole, it is necessary that there is a straight portion, and the aperture ratio can be increased by adjoining each hole portion at the straight portion. The opening area of the through hole is 0.05 mm ² to 2 mm ² . If it is smaller than 0.05 mm ² , hypochlorous acid and gas are not easily discharged, and the membrane is likely to deteriorate. If it is larger than 2 mm ² , the efficiency of electrolysis is reduced. More preferably, it is 0.1 mm ² to 1.5 mm ² . More preferably, it is 0.2 mm ² to 1 mm ² . Here, the straight portion includes one having a radius of curvature of 1.5 mm or more.

  The through-hole 43 is not limited to a rounded rectangular shape, and can be a rounded, polygonal shape such as a square, a rhombus, and a hexagon. In addition, a shape in which the rectangular short side and the corners on both sides thereof are replaced with one curved portion, that is, a pair of opposed curved portions and two straight portions connecting the curved portions can be formed. . Further, the first recess 40 is not limited to the configuration in which all the first recesses 40 are the through holes 43, but may include a first recess that is not in communication with the second recess 42. That is, there may be a first recess not communicating with the anode chamber. There may be one in which a part of the first recess communicates. For example, the first recess may have a rectangular recess shape that reaches from one end to the other end of the electrode excluding the seal portion, and a plurality of through holes may be disposed at intervals. The first recess that is not in communication has the effect of increasing the electrode area and the effect of promoting the diffusion of the substance.

The first electrode has many through holes. Among these through-holes, the through-hole having a curvature radius r of the bent portion of 0.005 mm to 0.5 mm and an opening area of 0.05 mm ² to 2 mm ² is preferably 80% or more. More preferably, it is 90% or more, More preferably, it is 95% or more.

  The area of the plurality of through holes communicating with the second recess 42 can be larger in the through hole formed in the central region of the second recess 42 than the area of the through hole formed in the peripheral region. By doing so, hypochlorous acid and gas generated by the electrolytic reaction around the second recess 42 are more easily discharged.

  In the embodiment, the peripheral wall defining the opening may have a tapered surface or a curved surface with a diameter increasing from the bottom of the hole portion toward the opening, that is, toward the first surface 21a. it can.

  FIG. 3 is an exploded perspective view of an electrode unit for producing hypochlorous acid water that can be used in the embodiment.

  In FIG. 3, the second electrode shows the same opening structure (mirror image) as the first electrode, but may be different.

  In the embodiment, as illustrated, a plurality of, for example, nine first concave portions 40 are provided to face one second concave portion 42. Each of the nine first recesses 40 communicates with the second recess 42 and forms a through hole 43 that penetrates the base material 21 together with the second recess 42. The interval W1 between adjacent through holes is set to be smaller than the interval W2 between the second recesses 42. Thereby, the number density of the 1st recessed part 40 in the 1st surface 21a is sufficiently larger than the number density of the 2nd recessed part 42 in the 2nd surface 21b.

  The second recesses 42 are formed, for example, in a rectangular shape, and are provided side by side in a matrix on the second surface 21b. The vertices of the rectangle may or may not be rounded. The peripheral wall defining each second recess 42 may be formed by a tapered surface 42a or a curved surface having a diameter that increases from the bottom of the recess toward the opening, that is, toward the second surface. . The interval between the adjacent second concave portions 42, that is, the width of the linear portion of the electrode is set to W2. In addition, the 2nd recessed part 42 is good also as another various shape, without being limited to rectangular shape. Moreover, the 2nd recessed part 42 may be formed not only regularly but in a row.

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. When it is a square opening, one side is preferably 1 mm to 40 mm, more preferably 2 mm to 30 mm, and still more preferably 3 mm to 20 mm. As the opening, various shapes such as a square, a rectangle, a rhombus, a circle, and an ellipse can be used. The opening area equal to the opening area of the square, preferably those from 1 mm ² of 1600 mm ^2. More preferably, it is 4 mm ² to 900 mm ² , and further preferably 9 mm ² to 400 mm ² . An opening that extends in one direction, such as a rectangle or an ellipse, and is connected to one end of the electrode excluding the seal portion is also possible.

  When the first recess and the second recess both have an opening that leads from one end of the electrode excluding the seal portion to the other end, they can be configured to be orthogonal or parallel. 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. In the first electrode 20 having a porous structure, the first recess is formed with a tapered surface or a curved surface where the opening on the first surface side is widened, so that the contact angle between the opening of the first recess and the porous diaphragm 24 is an obtuse angle. Thus, stress concentration on the porous diaphragm 24 can be reduced.

  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.

  4A to 4F are views showing an example of a method for manufacturing an 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. 4A and 4B, 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. 4C, the resist films 50a and 50b are exposed using an optical mask (not shown) to produce etching masks 52a and 52b, respectively.

  As shown in FIG. 4D, 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.

  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. The depth of the first recess 40 is T2, the depth of the second recess 42 is T3, and 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, 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.

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

  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.

  It is preferable that at least the first surface 21a of the substrate 21 is substantially flat except for the recess. For this reason, the surface roughness (roughness of the flat portion excluding the concave portion) of the base material 21 can be changed from 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 used on the anode side can contain an inorganic oxide having a positive zeta potential in the region of pH 2 to 6. 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 and titanium oxide can be used as the inorganic oxide having good chemical stability. Alternatively, preferably, zirconium oxide can be used as the 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 inorganic oxides, those in which the zeta potential tends to be negative in the alkaline region can be used, and examples of such inorganic oxides include zirconium oxide, titanium oxide, aluminum oxide, zircon, silicon oxide. Tungsten 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). As other polymers, for example, hydrocarbon polymers such as polyethylene and polypropylene, so-called engineering plastics such as polyimide, polysulfone, and polyphenylene sulfide can be used.

  The pore diameter of the porous diaphragm 24 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. 5, 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 24a covering the first surface 21a portion of the first electrode 20 and a second region 24b covering the openings of the plurality of first recesses 40 communicating with the second recesses 42. And 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 porous diaphragm 24, the surface pores in the first region are eliminated, that is, they are formed without pores, or the diameter of the surface pores in the first region 24a and the number density of the pores are made larger than those in the second region. By making it small, the electrolytic reaction in the area | region which contact | connects the 1st area | region 24a can be suppressed, and deterioration of the electrode unit 12 can be prevented. 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. 5 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 voltage application or load on the electrode unit 12 by the power supply 30 according to the detection information in accordance with a 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. 4E, 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. 4F, 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 high-efficiency electrolysis performance over a long period of time and an electrolysis apparatus using the electrode unit.

Next, various examples and comparative examples will be described.
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 the steps shown in FIGS. 4A to 4F to produce the first electrode 20.

  FIG. 6 schematically shows one embodiment of the shape of the through hole.

Of the first electrode 20, the thickness of the region including the first recess 40 (the depth of the first recess) is 0.15 mm, and the thickness of the region including the second recess 42 having a larger opening area than the first recess (first The depth of the two recesses) is 0.35 mm. As shown in the drawing, the through-hole 43 is a rhombus having rounded corners, the radius of curvature of each apex is 0.02 mm to 0.2 mm, and the side straight portion is 0.14 mm to 0.45 mm. Opening area is 0.28 mm ² from 0.20 mm ^2. As shown in the figure, the area of the plurality of through holes communicating with the second recess 42 is larger in the through hole 43C formed in the central region of the second recess 42 than the through hole 43P formed in the peripheral region.

  Similarly, the second recess 42 is a rhombus having rounded corners. One side of the rhombus is about 3.6 mm. The width W1 (W0) of the linear portion formed between the adjacent through holes 43 is about 0.14 mm, and the width W2 of the wide linear portion formed between the adjacent second concave portions 42 is about 0.86 mm. is there.

The etched electrode substrate 21 is treated at 80 ° C. for 1 hour in a 10 wt% oxalic acid aqueous solution. A solution prepared by adding 1-butanol to iridium chloride (IrCl ₃ .nH ₂ O) to 0.25 M (Ir) was applied to the first surface 21 a of the electrode substrate 21, and then dried and fired. Thus, the catalyst layer 28 is formed. 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 in which such coating, drying, and baking are repeated five times is cut into a reaction electrode area of 3 cm × 4 cm to form a first electrode (anode) 20.

  Ethanol and diethanolamine are added to tetraisopropoxytitanium (IV) in an ice bath, and ethanol mixed water is added dropwise with stirring to prepare a sol. Polyethylene glycol (molecular weight 5000) that makes the thin film porous by heat treatment and increases the viscosity of the sol is added to the sol returned to room temperature, and the first surface 21a of the electrode 20 is coated with a brush. The coated film is baked at 500 ° C. for 7 minutes. After coating and baking three times, the porous diaphragm 24 made of titanium oxide having a positive zeta potential at pH 2 to 6 is obtained by baking at 500 ° C. for 1 hour. The zeta potential of titanium oxide can be measured by, for example, electrophoresis (Zeta Sizer Nano ZS manufactured by Malvern). The pH of titanium oxide can be changed from acidic to alkaline by adding hydrochloric acid and sodium hydroxide to pure water.

  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 membrane 27 made of a titanium oxide film is produced in the same manner as the porous membrane 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 porous diaphragm 24, the porous polystyrene 25, the porous diaphragm 27, and the second electrode 22 are overlapped and fixed using a silicone sealant and a screw to produce the electrode unit 12. 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 102 for extracting hypochlorous acid water from the anode chamber 16 and a line 103 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 holding body (porous polystyrene) 25 of the electrode unit 12, a pipe and a pump are connected to the electrode unit, and a line for introducing an electrolyte containing chlorine ions into the electrolytic cell. 101 and a line 108 for collecting surplus electrolyte are secured.

  Electrolysis is performed using the electrolyzer 10 at a voltage of 3.9 V and a current of 1.5 A. Hypochlorous acid water is used on the first electrode (anode) 20 side, and hydrogen and hydroxide are used on the second electrode (cathode) 22 side. Produces sodium water. Even after 1000 hours of continuous operation, there is almost no increase in voltage or change in product concentration, and stable electrolytic treatment can be performed.

(Example 2)
In FIG. 7, the disassembled perspective view of the 1st modification of the electrode unit for hypochlorous acid water production which can be used for embodiment is shown. In FIG. 7, the second electrode has the same opening structure (mirror image) as the first electrode.

  The electrode unit 12 ′ is formed in the same manner as in Example 1 except that the first and second recesses and the first and second electrodes having through holes shown in FIG. 7 are used.

  As shown in the figure, for example, a plurality of, for example, nine first recesses 50 are provided to face one second recess 52. Each of these nine first recesses 50 communicates with the second recess 52 and forms a through hole 53 that penetrates the base material 21 together with the second recess 52. In FIG. 7, for ease of understanding, the number of the second opening is three, and the number of the first opening facing the second opening is nine. However, since the reaction electrode area is 3 cm × 4 cm, Has more openings than the dimensions shown below. An interval W1 'between adjacent through holes is set to be smaller than an interval W2' between the second recesses 52. Accordingly, the number density of the first recesses 50 on the first surface 21a 'is sufficiently larger than the number density of the second recesses 52 on the second surface 21b'.

The through-hole 53 has a shape in which both ends are semicircular rectangles, that is, both ends of two parallel straight lines are connected by a semicircle. The radius of curvature of each semicircle is 0.08 mm to 0.13 mm, the side straight part is about 3.0 mm, and the opening area is 0.7 mm ² to 0.8 mm ² .

  The second recess 52 is rectangular and one side is the entire length of the electrode excluding the seal portion. The width W1 ′ (W0) of the linear portion formed between the adjacent through holes is about 0.25 mm, and the width W2 ′ of the wide linear portion formed between the adjacent second concave portions 42 is about 1.8 mm. It is.

  An aqueous dispersion of Teflon particles containing titanium oxide particles having a particle size of 50 μm to 500 μm is applied to a glass cloth having a thickness of 100 μm as a porous diaphragm and dried. Further, 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 make a porous diaphragm. The zeta potential at pH 4 on the porous diaphragm surface is -12 mV.

  Using the electrodes 20 and 22 with a catalyst layer prepared in the same manner as in Example 1, an electrolytic apparatus having the structure shown in FIG. 1 is prepared.

  Using this electrolyzer, electrolysis was performed at a voltage of 4.2 V and a current of 1.5 A, hypochlorous acid water was supplied on the first electrode (anode) 20 side, and hydrogen and hydroxylation were supplied on the second electrode (cathode) 22 side. Produces sodium water. Even after 1000 hours of continuous operation, there is almost no increase in voltage or change in product concentration, and stable electrolytic treatment can be performed.

(Example 3)
As a porous film, an aqueous dispersion mixture of a strongly basic gel-type anion exchange resin having a particle size of 400 to 500 μm and polypropylene fine particles is applied to a polyethylene cloth having a thickness of 150 μm and dried. Dry in the atmosphere at 80 ° C. for 1 hour to make a porous diaphragm. An electrolytic apparatus is manufactured in the same manner as in Example 2 except that this porous diaphragm is used as the anode-side porous film 24 in FIG. 1 and Nafion 117 is used as the cathode-side porous film.

  Using this electrolyzer, electrolysis was performed at a voltage of 4.3 V and a current of 1.5 A, hypochlorous acid water was used on the first electrode (anode) side, and hydrogen and sodium hydroxide water were used on the second electrode (cathode) side. Is generated. Even after 1000 hours of continuous operation, there is almost no increase in voltage or change in product concentration, and stable electrolytic treatment can be performed.

Example 4
The through hole is a rhombus having rounded corners, the radius of curvature of each corner is 0.005 mm to 0.2 mm, the side straight part is 0.05 mm to 0.40 mm, and the opening area is 0.05 mm. The electrolytic apparatus having the structure shown in FIG. 1 is produced in the same manner as in Example 1 except that the first electrode and the second electrode which are ² to 0.27 mm ² are used.

  Using this electrolyzer, electrolysis was performed at a voltage of 4.0 V and a current of 1.5 A. Hypochlorous acid water was used on the first electrode (anode) 20 side, and hydrogen and hydroxide were used on the second electrode (cathode) 22 side. Produces sodium water. Even after 1000 hours of continuous operation, there is almost no increase in voltage or change in product concentration, and stable electrolytic treatment can be performed.

(Example 5)
The through-hole is a rhombus having rounded corners, the radius of curvature of each corner is 0.03 mm to 0.5 mm, the side straight part is 0.4 mm to 1.2 mm, and the opening area is 0.5 mm. An electrolytic apparatus having the structure shown in FIG. 1 is produced in the same manner as in Example 1 except that the first electrode and the second electrode having a diameter of ² to 2 mm ² are used.

  Using this electrolyzer, electrolysis was performed at a voltage of 4.2 V and a current of 1.5 A, hypochlorous acid water was supplied on the first electrode (anode) 20 side, and hydrogen and hydroxylation were supplied on the second electrode (cathode) 22 side. Produces sodium water. Even after 1000 hours of continuous operation, there is almost no increase in voltage or change in product concentration, and stable electrolytic treatment can be performed.

(Example 6)
In FIG. 8, the disassembled perspective view of the 2nd modification of the electrode unit for hypochlorous acid water production which can be used for embodiment is shown. In FIG. 8, the second electrode has the same opening structure (mirror image) as the first electrode.

  The electrode unit 112 is formed in the same manner as in Example 1 except that the first electrode 120 and the second electrode 122 having the first recess 63 and the second recess 62 shown in FIG. 8 are used.

  As shown in the figure, each of the four first recesses 63 has a rectangular shape that reaches from the upper end to the lower end of the electrode 123 except for the seal portion 124, and the first recess 63 does not communicate with the second surfaces 121b and 123b. It has a recessed part and the opening part (through-hole) 61 connected to 2nd surface 121b, 123b. The through hole 61 is disposed in the first recess 63 with an interval R2. For example, two first recesses 63 are provided to face one second recess 62. Five through holes 61 respectively disposed in the two first recesses 63 communicate with one second recess 62. The number density of the first recesses 63 on the first surface 121a is sufficiently larger than the number density of the second recesses 62 on the second surface 121b. In FIG. 8, the number of openings is shown to be small for easy understanding, but since the reaction electrode area is 3 cm × 4 cm, the number of openings is actually larger from the dimensions shown below.

The first recess 63 is rectangular, and the thickness of the region including the first recess 63 (the depth of the first recess) in the first electrode 120 is 0.1 mm, and the second opening area is wider than the first recess 63. The thickness of the region including the recess 62 (depth of the second recess) is 0.3 mm. The through-hole 61 is a square having rounded corners, the radius of curvature of each vertex is 0.04 mm to 0.1 mm, and the side straight portion is 0.3 mm to 0.35 mm. The opening area is 0.15 mm ² to 0.3 mm ² .

  The second recess 62 is rectangular and one side is the entire length of the electrode excluding the seal portion. The first recess and the second recess are parallel. The width W3 of the flat portion formed between the adjacent first recesses 63 is about 0.5 mm, and the width W4 between the adjacent through holes 61 is about 1.0 mm. The first recess not communicating with the second recess has an effect of increasing the electrode area and stabilizing the voltage.

  When titanium oxide particles having a particle size of 50 to 500 μm are contained in a glass cloth having a thickness of 100 μm as a porous diaphragm, an aqueous dispersion of Teflon particles is applied and dried. Further, 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 make a porous diaphragm. The zeta potential at pH 4 on the porous diaphragm surface is -12 mV.

  Using the electrodes 120 and 122 with a catalyst layer prepared in the same manner as in Example 1, an electrolytic apparatus having the structure shown in FIG. 1 is prepared.

  Using this electrolyzer, electrolysis was performed at a voltage of 4.0 V and a current of 1.5 A, hypochlorous acid water was supplied on the first electrode (anode) 120 side, and hydrogen and hydroxide were supplied on the second electrode (cathode) 122 side. Produces sodium water. Even after 1000 hours of continuous operation, there is almost no increase in voltage or change in product concentration, and stable electrolytic treatment can be performed.

(Example 7)
In FIG. 9, the disassembled perspective view of the 3rd modification of the electrode unit for hypochlorous acid water production which can be used for embodiment is shown. In FIG. 9, the second electrode has the same opening structure (mirror image) as the first electrode.

  The electrode unit 212 is formed in the same manner as in Example 1 except that the first electrode 220 and the second electrode 222 having the first recess 63 and the second recess 62 shown in FIG. 9 are used.

  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 through holes 61 are disposed in the first recess 63 with three intervals. Each of the three second recesses has a rectangular shape that reaches from the upper end to the lower end of the electrode 223 excluding the seal portion 224. Six through-holes 61 respectively disposed in the six first recesses 63 communicate with one second recess 62. The number density of the first recesses 63 on the first surface 221a is sufficiently larger than the number density of the second recesses 62 on the second surface 221b. In FIG. 9, the number of openings is shown to be small for easy understanding, but since the reaction electrode area is 3 cm × 4 cm, the number of openings is actually larger from the dimensions shown below.

Of the first electrode 120, the thickness of the region including the first recess 63 (the depth of the first recess) is 0.15 mm, and the thickness of the region including the second recess 62 having a larger opening area than the first recess 63 ( The depth of the second recess) is 0.35 mm. The through hole has a shape in which both ends are semicircular rectangles, that is, both ends of two parallel straight lines are connected by a semicircle. The radius of curvature of each semicircle is 0.08 mm to 0.13 mm, the side straight part is about 3.0 mm, and the opening area is 0.7 mm ² to 0.8 mm ² .

  The first recess and the second recess are orthogonal. The width W5 of the flat portion formed between the adjacent first recesses 63 is about 0.25 mm, and the width W6 between the adjacent second recesses is about 1.0 mm. The first recess not communicating with the second recess has an effect of increasing the electrode area and stabilizing the voltage.

  When titanium oxide particles having a particle diameter of 50 to 500 μm are contained in a glass cloth having a thickness of 100 μm as a porous diaphragm, an aqueous dispersion of polyvinylidene fluoride particles is applied and dried. Further, 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 make a porous diaphragm. The zeta potential at pH 4 on the porous diaphragm surface is -10 mV.

  Using the electrodes 220 and 222 with a catalyst layer prepared in the same manner as in Example 1, an electrolytic device having the structure shown in FIG. 1 is prepared.

  Using this electrolyzer, electrolysis was performed at a voltage of 4.1 V and a current of 1.5 A. Hypochlorous acid water was used on the first electrode (anode) 120 side, and hydrogen and hydroxide were used on the second electrode (cathode) 122 side. Produces sodium water. Even after 1000 hours of continuous operation, there is almost no increase in voltage or change in product concentration, and stable electrolytic treatment can be performed.

(Comparative Example 1)
The electrolytic apparatus is configured in the same manner as in Example 1 except that the first electrode and the second electrode having a radius of curvature at each corner of the through hole of 0.003 mm to 0.01 mm are used.

  Using this electrolyzer, electrolysis was performed at a voltage of 4.2 V and a current of 1.5 A, hypochlorous acid water was supplied on the first electrode (anode) 20 side, and hydrogen and hydroxylation were supplied on the second electrode (cathode) 22 side. Produces sodium water. After 1000 hours of continuous operation, an increase in voltage and a decrease in product concentration are observed.

(Comparative Example 2)
The electrolytic apparatus is configured in the same manner as in Example 1 except that the first electrode and the second electrode having an opening area of the through hole of 2.0 mm ² to 2.4 mm ² are used.

  In this electrolyzer, electrolysis can be performed at a voltage of 4.0 V and a current of 1.5 A, but the efficiency of hypochlorous acid water generation is 70% as compared with Example 1.

(Comparative Example 3)
The electrolytic apparatus is configured in the same manner as in Example 1 except that the first electrode and the second electrode having an opening area of the through hole of 0.03 mm ² to 0.05 mm ² are used.

  Using this electrolyzer, electrolysis was performed at a voltage of 4.0 V and a current of 1.5 A. Hypochlorous acid water was used on the first electrode (anode) 20 side, and hydrogen and hydroxide were used on the second electrode (cathode) 22 side. Produces sodium water. After 1000 hours of continuous operation, an increase in voltage and a decrease in product concentration are observed.

(Comparative Example 4)
The electrolytic apparatus is configured in the same manner as in Example 1 except that the first electrode and the second electrode having a curvature radius of 0.3 mm to 0.7 mm at each corner of the through hole are used.

  In this electrolyzer, electrolysis can be performed at a voltage of 4.1 V and a current of 1.5 A, but the efficiency of hypochlorous acid water generation is 60% as compared with Example 1.

(Electrode, electrode unit, and electrolysis apparatus according to other embodiments)
Below, the electrode, electrode unit, and electrolysis apparatus concerning other embodiment are demonstrated.

  The electrode according to this embodiment has 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 plurality of through-holes include through-holes having different sizes, and are arranged such that the aperture ratio of the through-holes gradually increases along the direction from one end of the electrode toward the other opposite end.

  The electrode unit according to this embodiment is an electrode unit using the above 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. The second electrode, the porous membrane provided on the first surface of the first electrode, and the electrolyte solution holding structure provided between the porous membrane and the second electrode.

  The first electrode is provided with a plurality of through holes penetrating from the first surface to the second surface. The plurality of through-holes include through-holes having different sizes, and are arranged so that the opening ratio of the through-holes gradually increases along the direction from one end of the first electrode to the other opposite end.

  The electrolysis apparatus according to this embodiment is an example of an electrolysis apparatus to which the electrode and an electrode unit using the 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.

  According to the embodiment, since the aperture ratio of the through holes is arranged so as to gradually increase along the direction from one end of the first electrode toward the opposite other end, ions generated by electrolysis pass through the electrode. The pH can be controlled by controlling the amount to be produced.

  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.

  The direction from the one end of the first electrode to the opposite other end can be the direction along the flow direction in the first electrode chamber or the opposite direction.

  The direction of flow in the first electrode chamber refers to the direction of flow of water introduced into the first electrode chamber, water containing chlorine by electrolysis, hypochlorous acid, or the like.

  When the percentage of the opening area per unit area in each region divided into two or more from one end to the other end of the first electrode is defined as the opening ratio, it is downstream of the upstream region in the flow direction in the first electrode chamber. The aperture ratio in the region can be increased or decreased.

  When the flow is generated by natural convection in the electrolytic cell, the direction from one end of the first electrode to the other opposite end can be from the top to the bottom or from the bottom to the top of the first electrode chamber.

  When the flow is generated by natural convection in the electrolytic cell, the opening ratio is defined as a percentage of the opening area per unit area in each region divided into two or more from one end of the first electrode toward the other end. The aperture ratio of the lower part can be made larger or smaller than the upper part of the electrode chamber.

  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. 10 is a diagram schematically illustrating an example of the electrolysis apparatus according to the 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 located in the anode chamber 16, a second electrode (counter electrode) 22 located in the cathode chamber 18, and a catalyst layer 28 on the first surface 21 a of the first electrode 20. Formed and having a porous diaphragm 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.

  A plurality of first holes 40 are formed in the first surface 21a of the base material 21 and open to the first surface 21a. A plurality of second holes 42 are formed in the second surface 21b and open to the second surface 21b. The opening diameter R1 of the first hole 40 on the porous diaphragm 24 side is smaller than the opening diameter R2 of the second hole 42, and the number of holes is such that the first hole 40 is the second hole 42. More are formed. The depth of the first hole 40 is T2, the depth of the second hole 42 is T3, and T2 + T3 = T1. In this embodiment, for example, T2 <T3.

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

  As shown in FIG. 11, 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 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, 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. Furthermore, a tank for storing alkaline electrolyzed water may be provided.

  The first electrode 20 has different opening ratios on the water supply line L2 side and the line L4 side for taking out the acidic electrolyzed water.

  The aperture ratio can be measured using an optical microscope. The aperture ratio of a certain part of the electrode is a square that contains at least 100 openings completely, and the opening area of the through-hole included in it is measured (the narrowest opening area when the taper is on the side), and the total A value obtained by dividing the area by the square area, that is, the percentage of the opening area per unit area is obtained. When a part of the opening is formed around the square, the opening area in the square is added to the total area.

  When the percentage of the opening area per unit area of each region divided into two or more from one end of the first electrode toward the other end is defined as the opening ratio, the first opening ratio and the first region of the first region It is preferable that the ratio of the second area different from the second area to the second aperture ratio is in the range of 1: 1.05 to 1:10.

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, the side reaction that generates oxygen may occur 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.

From reaction formula (4), it can be seen that by taking two electrons, one hypochlorous acid molecule and one proton are generated, and one oxygen molecule and two protons are generated from reaction formula (8). That is, even if the current amount is the same, when oxygen is generated as a side reaction, more protons are generated and the pH is lowered. Usually, since the activation energy of the reaction of the reaction formula (7) is large, the reaction of the reaction formula (3) has priority. However, when the concentration of chloride ions necessary for the reaction is small, the reaction of the reaction formula (7) easily occurs. If the aperture ratio is large, chloride ions are likely to flow out from the openings and the concentration of chloride ions tends to decrease. Therefore, oxygen is easily generated and protons are generated more. In this case, the difference in the amount of proton generation is at most twice. Since the pH value is a logarithm of the concentration, this difference becomes particularly large in a high pH region. Protons are generated on the porous diaphragm side of the anode with the catalyst, but are not easily emitted from the opening of the anode due to electrostatic repulsion with the anode. From the reaction formula (6), OH ⁻ is generated twice as many protons at the cathode. OH ^{− is} also difficult to go out due to electrostatic repulsion. Residual protons and OH ⁻ react by diffusing in the reverse direction through the porous diaphragm, and thus the pH outside the anode is more difficult to lower.

Since the water stream supplied to the charge cell is usually neutral, protons generated on the upstream side are easily discharged to the outside due to a large concentration gradient. On the downstream side, the pH of the water stream is lowered, and diffusion of protons to the outside hardly occurs. However, if the opening ratio on the downstream side is large, the amount of proton generation increases, the concentration gradient increases, and the proton easily flows out to the outside due to the large opening ratio, and the pH tends to decrease. Further, since the water pressure is lower on the downstream side, the oxygen gas is likely to escape, so that the reaction of the reaction formula (8) is promoted and the pH tends to decrease. Even on the cathode side, when the opening ratio on the downstream side is large, OH ⁻ is easily released, so that secondary protons easily flow out to the outside.

  On the other hand, when the aperture ratio of the electrode placed on the upstream side of the water flow is larger than that on the downstream side, the concentration gradient of protons generated downstream is small, so that it is difficult to diffuse and the aperture ratio is small, so it is difficult to flow out to the outside. . Therefore, the pH is difficult to decrease. Further, since the upstream side has a higher water pressure, it is difficult for oxygen gas to escape, so that the reaction of the reaction formula (8) is suppressed and the pH is hardly lowered.

  Here, the water flow is caused by line piping with a pump (not shown), but natural convection due to heat and natural convection due to generated gas cause a water flow from the bottom to the top due to the effect of gravity, which is similar to the effect due to line piping. The effect of.

  In order to produce the above effects, it is preferable that the difference in the opening ratio of the upper part with respect to the lower part is in the range of 1: 1.05 to 1:10. If it is less than 1: 1.05, the effect tends to decrease. On the other hand, if it is larger than 1:10, one electrode reaction is inhibited and the overall efficiency is lowered. 1: 2 to 1: 7 is more preferred, and 1: 3 to 1; 6 is even more preferred.

The opening area of the through hole on the porous membrane side is preferably 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. If it is larger than 4 mm ^2, the efficiency of the electrode reaction decreases. More preferably, it is 0.1 mm ² to 1.5 mm ² . More preferably, it is 0.2 mm ² to 1 mm ² .

  It is preferable that the difference in opening area on the porous membrane side of the through hole is 10 times or less. If it is larger than 10 times, the reaction tends to be inhibited at one opening. More preferably, it is 7 times or less, More preferably, it is 5 times or less.

  The length of the entire electrode is preferably from 5 cm to 100 cm in the water flow direction. If it is smaller than 5 cm, the effect due to the difference in the aperture ratio tends to be difficult. If it is larger than 100 cm, it tends to be difficult to produce the electrode unit. More preferably, it is 7 cm or more and 70 cm or less, More preferably, it is 10 cm or more and 50 cm or less.

  In the embodiment, the peripheral wall defining the opening may have a tapered surface or a curved surface with a diameter increasing from the bottom of the hole portion toward the opening, that is, toward the first surface 21a. it can.

  FIG. 12 schematically shows an exploded perspective view showing an example of an electrode unit using the electrode according to the embodiment.

  For example, the electrodes and the electrode unit can be arranged in such a state that a water flow occurs from the bottom to the top.

  As shown in the drawing, a plurality of, for example, nine first recesses 40 are provided to face one second recess 42. Each of these nine first recesses 40 communicates with the second recess 42 and forms a through hole that penetrates the base material 21 together with the second recess 42. The interval W1 between adjacent through holes is set to be smaller than the interval W2 between the second recesses 42. Thereby, the number density of the 1st recessed part 40 in the 1st surface 21a is sufficiently larger than the number density of the 2nd recessed part 42 in the 2nd surface 21b. The opening area of the first recess 40 gradually increases in the direction from the downstream to the upstream. The 1st recessed part 40 located upstream is larger than the 1st recessed part 40 located downstream, and its aperture ratio is also large. The size of the opening area of each second recess 42 is the same upstream and downstream.

  The second recesses 42 are formed, for example, in a rectangular shape, and are provided side by side in a matrix on the second surface 21b. The vertices of the rectangle may or may not be rounded. The peripheral wall defining each second recess 42 may be formed by a tapered surface 42a or a curved surface whose diameter increases from the bottom of the hole toward the opening, that is, toward the second surface. Good. The interval between the adjacent second concave portions 42, that is, the width of the linear portion of the electrode is set to W2. In addition, the 2nd recessed part 42 is good also as another various shape, without being limited to rectangular shape. Moreover, the 2nd recessed part 42 may be formed not only regularly but in a row.

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. When it is a square opening, one side is preferably 1 mm to 40 mm, more preferably 2 mm to 30 mm, and still more preferably 3 mm to 20 mm. As the opening, various shapes such as a square, a rectangle, a rhombus, a circle, and an ellipse can be used. The opening area equal to the opening area of the square, preferably those from 1 mm ² of 1600 mm ^2. More preferably, it is 4 mm ² to 900 mm ² , and further preferably 9 mm ² to 400 mm ² . 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.

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

  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 diffusion of the substance.

  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.

  13A to 13F are views showing an example of the electrode unit 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. 13A and 13B, one flat substrate 21 is prepared.

  Resist films 50 a and 50 b are applied to the first surface 21 a and the second surface 21 b of the substrate 21.

  As shown in FIG. 13C, 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. 13D, 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 formed. 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. The depth of the first recess 40 is T2, the depth of the second recess 42 is T3, and 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, 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.

  When both the first recess and the second recess have an opening that leads from one end of the electrode excluding the seal portion to the other end, they can be configured to be orthogonal or parallel. 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.

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

  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.

  It is preferable that the surface of the positive electrode on the porous membrane side 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 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, 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). As other polymers, for example, hydrocarbon polymers such as polyethylene and polypropylene, so-called engineering plastics such as polyimide, polysulfone, and polyphenylene sulfide can be used.

  The pore diameter of the porous diaphragm 24 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. 5, 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. 5 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. 13E, 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. 13F, 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 high-efficiency electrolysis performance over a long period of time and an electrolysis apparatus using the electrode unit.

Next, various examples and comparative examples will be described.
Example (Example 8)
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 shown in FIGS. 13A and 13F to produce the first electrode 20. 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 0.15 mm, and the thickness of the region including the second recess 42 having a large area (the second recess). Is 0.35 mm. The first recessed hole portion 40 is a square. The second recess 42 is also a square, and one side of the square is about 3.6 mm. Although not shown, in Example 8, the first recesses 40 are arranged so that the aperture ratio increases along the direction of the water flow. That is, the aperture ratio is larger downstream.

  The electrode was divided into six equal parts, and the average opening ratio and opening area of the through holes in the central portion of each region were measured.

  FIG. 14 is a schematic diagram showing the position of each region.

As a result of the average opening ratio and opening area of the through holes included in the second recesses at the positions of the respective regions, the results are as follows: region (1) 35% 0.35 mm ² , region (2) 34% 0.34 mm ² , region (3) 25% 0.25 mm ^2, the area (4) 25% 0.25mm ^2, region (5) 15% 0.15mm ^2, a region (6) 14% 0.14mm ^2.

The etched electrode substrate 21 is treated at 80 ° C. for 1 hour in a 10 wt% oxalic acid aqueous solution. A solution prepared by adding 1-butanol to iridium chloride (IrCl ₃ .nH ₂ O) to 0.25 M (Ir) was applied to the first surface 21 a of the electrode substrate 21, and then dried and fired. Thus, the catalyst layer 28 is formed. 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.

  Ethanol and diethanolamine are added to tetraisopropoxytitanium (IV) in an ice bath, and ethanol mixed water is added dropwise with stirring to prepare a sol. Polyethylene glycol (molecular weight 5000) that makes the thin film porous by heat treatment and increases the viscosity of the sol is added to the sol returned to room temperature, and the first surface 21a of the electrode 20 is coated with a brush. The coated film is baked at 500 ° C. for 7 minutes. After coating and baking three times, the porous diaphragm 24 made of titanium oxide having a positive zeta potential at pH 2 to 6 is obtained by baking at 500 ° C. for 1 hour. The zeta potential of titanium oxide can be measured by, for example, electrophoresis (Zeta Sizer Nano ZS manufactured by Malvern). The pH of the measurement solution can be changed from acidic to alkaline by adding hydrochloric acid and sodium hydroxide to pure water.

  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 membrane 27 made of a titanium oxide film is produced in the same manner as the porous membrane 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 porous diaphragm 24, the porous polystyrene 25, the porous diaphragm 27, and the second electrode 22 are overlapped 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. The electrodes are installed so that the aperture ratio of the first hole on the downstream side of the flow path is large. 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. Thereby, an electrolyzer having the same configuration as that of FIG. 11 is obtained.

  Electrolysis is performed using the electrolyzer 10 at a flow rate of 2 L / min, a voltage of 3.9 V, and a current of 20 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 90% and the pH is 2.5.

Example 9
An electrolytic device is fabricated in the same manner as in Example 8 except that the arrangement of the electrodes is changed and the downstream opening ratio is small. Electrolysis is performed at a voltage of 3.9 V and a current of 20 A, and hypochlorous acid water is generated on the first electrode (anode) 20 side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) 22 side. The production efficiency of hypochlorous acid is 92% and the pH is 4.6.

(Example 10)
FIG. 15 shows another example of the electrode unit according to the embodiment. The electrode has a length in the water flow direction of 15 cm and a width of 10 cm.

  An electrode unit 12 'is formed in the same manner as in Example 8 except that the first electrode and the second electrode having the first recess and the second recess shown in FIG. 15 are used.

  As illustrated, the first electrode 20 ′ and the second electrode 22 ′ are provided with a plurality of, for example, nine first recesses 50 facing one second recess 52. Each of these nine first recesses 50 communicates with the second recess 52 and forms a through hole that penetrates the base material 21 together with the second recess 52. The first recesses 50 are arranged so that the aperture ratio gradually increases along the direction along the direction of the water flow. The interval W1 'between adjacent through holes is set smaller than the interval W2' between the second recesses 52. Accordingly, the number density of the first recesses 50 on the first surface 21a 'is sufficiently larger than the number density of the second recesses 52 on the second surface 21b'.

The first recess 50 has a shape in which both ends are semicircular rectangles, that is, both ends of two parallel straight lines are connected by a semicircle. In each position shown in FIG. 14, the average opening ratio and opening area of the through-holes included in the second recess are region (1) 30% 1.1 mm ² , region (2) 31% 1.2 mm ² , region ^{(3) 20%, 0.75mm 2} , region (4) 20% 0.75mm ^2, region (5) 10% 0.38mm ^2, a region (6) 11% 0.41mm ^2.

  An electrode unit 12 'is formed in the same manner as in Example 8 except that the first electrode and the second electrode having the first recess and the second recess shown in FIG. 15 are used.

  The second recess 52 is rectangular and one side is the entire length of the electrode excluding the seal portion. The width W1 ′ (W0) of the linear portion formed between the adjacent through holes is about 0.25 mm, and the width W2 ′ of the wide linear portion formed between the adjacent second concave portions 42 is about 1.8 mm. It is.

  An aqueous dispersion mixture of titanium oxide particles having a particle diameter of 100 to 500 μm and polyvinylidene fluoride particles is applied to a glass cloth having a thickness of 100 μm as a porous diaphragm and dried. Further, 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 make a porous diaphragm. The zeta potential at pH 4 on the porous diaphragm surface is -12 mV.

  Using the electrodes 20 and 22 with the catalyst layer prepared in the same manner as in Example 8, an electrolytic apparatus having the structure shown in FIG. 10 is prepared.

  Using this electrolyzer, electrolysis was performed at a flow rate of 2 L / min, a voltage of 3.9 V, and a current of 20 A, hypochlorous acid water was supplied on the first electrode (anode) 20 side, and hydrogen was supplied on the second electrode (cathode) 22 side. And produces aqueous sodium hydroxide. The production efficiency of hypochlorous acid is 93% and the pH is 2.6.

(Example 11)
An electrolytic device is manufactured in the same manner as in Example 10 except that the arrangement of the electrodes is changed and the downstream opening ratio is small. Electrolysis is performed at a voltage of 3.9 V and a current of 20 A, and hypochlorous acid water is generated on the first electrode (anode) 20 side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) 22 side. The production efficiency of hypochlorous acid is 94% and the pH is 4.7.

Example 12
The average opening ratio and opening area of the through-holes of the electrodes used are region (1) 35% 0.35 mm ² , region (2) 36% 0.36 mm ² , region (3) 34% 0.34 mm ² , region (4 ) 34% 0.33 mm ² , region (5) 33% 0.33 mm ² , region (6) 32% 0.32 mm ² , and an electrolytic device is manufactured in the same manner as in Example 8. Electrolysis is performed at a voltage of 3.9 V and a current of 20 A, and hypochlorous acid water is generated on the first electrode (anode) 20 side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) 22 side. The production efficiency of hypochlorous acid is 90% and the pH is 3.3.

(Comparative Example 5)
The electrolytic device is manufactured in the same manner as in Example 8 except that the aperture ratio from the position region (1) to the region (6) in the electrode is 18 to 20%, and an electrode that is not biased is used. Electrolysis is performed at a voltage of 4.0 V and a current of 20 A, and hypochlorous acid water is generated on the first electrode (anode) 20 side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) 22 side. The production efficiency of hypochlorous acid is 90% and the pH is 3.5, indicating an intermediate pH value.

(Example 13)
FIG. 16 is a diagram schematically illustrating another example of the electrolysis apparatus according to the embodiment.

  As shown in FIG. 16, this electrolyzer 310 has a cathode chamber 318 and an anode chamber 316 arranged so as to surround the cathode chamber 318, and a batch type in which a water flow is formed by natural convection without a channel and piping. 10 except that the electrolytic cell 311 is used. The capacities of the anode chamber 316 and the cathode chamber 18 are 2 L and 0.1 L, respectively, and the first concave portion is arranged so that the aperture ratio of the upper portion of the electrode is increased by using an electrode manufactured in the same manner as in Example 10. .

  Electrolysis is performed at a voltage of 3 V and a current of 4 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 92% and the pH is 3.0.

(Example 14)
An electrolytic device is manufactured in the same manner as in Example 13 except that the electrode arrangement is changed in the reverse direction and the aperture ratio on the lower side is increased. Electrolysis is performed at a voltage of 3 V and a current of 4 A for 5 minutes, and hypochlorous acid water is generated on the first electrode (anode) side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) side. The production efficiency of hypochlorous acid is 90% and the pH is 4.0.

(Example 15)
FIG. 17 shows still another example of the electrode unit according to the embodiment. The electrode has a length in the water flow direction of 15 cm and a width of 10 cm.

  An electrode unit 12 'is formed in the same manner as in Example 8 except that the first electrode and the second electrode having the first recess and the second recess shown in FIG. 17 are used.

  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 through holes 61 are arranged in the first concave hole portion 63 with three intervals. Each of the three second recesses has a rectangular shape that reaches from the upper end to the lower end of the electrode 223 excluding the seal portion 224. Six through-holes 61 respectively disposed in the six first recesses 63 communicate with one second recess 62. The number density of the first recesses 63 on the first surface 221a is sufficiently larger than the number density of the second recesses 62 on the second surface 221b. In FIG. 15, the number of openings is shown to be small for easy understanding, but since the reaction electrode area is 3 cm × 4 cm, the number of openings is actually larger from the dimensions shown below.

Of the first electrode 120, the thickness of the region including the first recess 63 (the depth of the first recess) is 0.15 mm, and the thickness of the region including the second recess 62 having a larger opening area than the first recess 63 ( The depth of the second recess) is 0.35 mm. The through hole has a shape in which both ends are semicircular rectangles, that is, both ends of two parallel straight lines are connected by a semicircle. When the electrode is divided into six equal parts, the average opening ratio and opening area of the through hole in the central portion are as follows: region (1) 31% 1.2 mm ² , region (2) 31% 1.2 mm ² , region (3) 20% 0.75 mm ² , region (4) 20% 0.75 mm ² , region (5) 10% 0.38 mm ² , region (6) 10% 0.38 mm ² .

  The first recess and the second recess are orthogonal. The width W5 of the flat portion formed between the adjacent first recesses 63 is about 0.25 mm, and the width W6 between the adjacent second recesses is about 1.0 mm. The first recess not communicating with the second recess has an effect of increasing the electrode area and stabilizing the voltage.

  When titanium oxide particles having a particle diameter of 50 to 500 μm are contained in a glass cloth having a thickness of 100 μm as a porous diaphragm, an aqueous dispersion of polyvinylidene fluoride particles is applied and dried. Further, 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 make a porous diaphragm. The zeta potential at pH 4 on the porous diaphragm surface is -10 mV.

  Using the electrodes 220 and 222 with a catalyst layer prepared in the same manner as in Example 8, an electrolytic apparatus having the structure shown in FIG. 10 is prepared.

  Using this electrolyzer, electrolysis was performed at a flow rate of 2 L / min, a voltage of 3.9 V, and a current of 20 A, hypochlorous acid water was supplied on the first electrode (anode) 20 side, and hydrogen was supplied on the second electrode (cathode) 22 side. And produces aqueous sodium hydroxide. The production efficiency of hypochlorous acid is 94% and the pH is 2.6.

(Comparative Example 6)
An electrolytic device is fabricated in the same manner as in Example 13 except that the same electrode as in Comparative Example 5 is used. Electrolysis is performed at a voltage of 4.0 V and a current of 4 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 87% and the pH is 3.5, indicating an intermediate pH value.

(Example 16)
The average opening ratio and opening area of the through holes are as follows: region (1) 50% 0.50 mm ² , region (2) 51% 0.51 mm ² , region (3) 34%, 0.34 mm ² , region (4) 34 The electrolytic device is fabricated in the same manner as in Example 8 except that the thickness is 0.33 mm ² , the region (5) is 5% 0.05 mm ² , and the region (6) is 5% 0.05 mm ² . Electrolysis is performed at a voltage of 4.2 V and a current of 20 A, and hypochlorous acid water is generated on the first electrode (anode) 20 side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) 22 side. The production efficiency of hypochlorous acid is 80% and the pH is 2.7.

(Example 17)
The average opening ratio and opening area of the through holes are: region (1) 50% 0.50 mm ² , region (2) 51% 0.51 mm ² , region (3) 34%, 0.34 mm ² _, region (4) 32 An electrolytic device is manufactured in the same manner as in Example 8 except that the thickness is% 0.32 mm ² , the region (5) is 4% 0.04 mm ² , and the region (6) is 4% 0.04 mm ² . Electrolysis is performed at a voltage of 4.2 V and a current of 20 A, and hypochlorous acid water is generated on the first electrode (anode) 20 side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) 22 side. The production efficiency of hypochlorous acid is 75% and the pH is 2.8.

(Example 18)
The average opening ratio and opening area of the through holes are as follows: region (1) 60% 4.0 mm ² , region (2) 60% 4.0 mm ² , region (3) 30%, 2.0 mm ² , region (4) 30 % 2.0 mm ² , region (5) 8% 0.53 mm ² , region (6) 8% 0.53 mm ² , width W5 is about 0.20 mm, and width W6 between adjacent second recesses is about 0. An electrolytic device is manufactured in the same manner as in Example 15 except that the thickness is 50 mm. Electrolysis is performed at a voltage of 4.2 V and a current of 20 A, and hypochlorous acid water is generated on the first electrode (anode) 20 side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) 22 side. The production efficiency of hypochlorous acid is 70% and the pH is 2.5.

(Example 19)
The average opening ratio and the opening area of through holes, the area (1) 65% 4.3 mm ^2, area (2) 65% 4.3 mm ^2, area (3) 30%, 2.0 mm ^2, the area (4) 30 % 2.0 mm ² , region (5) 8% 0.53 mm ² , region (6) 8% 0.53 mm ² , width W5 is about 0.20 mm, and width W6 between adjacent second recesses is about 0.00. An electrolytic device is manufactured in the same manner as in Example 15 except that the thickness is 5 mm. Electrolysis is performed at a voltage of 4.2 V and a current of 20 A, and hypochlorous acid water is generated on the first electrode (anode) 20 side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) 22 side. The production efficiency of hypochlorous acid is 60% and the pH is 2.5.

(Example 20)
The average opening ratio and opening area of the through holes are as follows: region (1) 20% 0.20 mm ² , region (2) 20% 0.20 mm ² , region (3) 5%, 0.05 mm ² , region (4) 5 An electrolytic device is fabricated in the same manner as in Example 8 except that the thickness is 0.05 mm ² , the region (5) is 1% 0.01 mm ² , and the region (6) is 1% 0.01 mm ² . Electrolysis is performed at a voltage of 4.2 V and a current of 20 A, and hypochlorous acid water is generated on the first electrode (anode) 20 side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) 22 side. The production efficiency of hypochlorous acid is 75% and the pH is 3.2.

(Example 21)
The average opening ratio and opening area of the through holes are as follows: region (1) 20% 0.20 mm ² , region (2) 20% 0.20 mm ² , region (3) 5%, 0.05 mm ² , region (4) 5 % 0.05 mm ^2, the area (5) 0.8% 0.008mm ^2, except that a region (6) 0.7% 0.007mm ² to prepare an electrolyte system in the same manner as in example 8 . Electrolysis is performed at a voltage of 4.2 V and a current of 20 A, and hypochlorous acid water is generated on the first electrode (anode) 20 side, and hydrogen and sodium hydroxide water are generated on the second electrode (cathode) 22 side. The production efficiency of hypochlorous acid is 65% and the pH is 3.3.

(Example 22)
The electrolysis apparatus is produced in the same manner as in Example 8, except that the first electrode of the electrolysis apparatus produced in Example 8 is removed from the electrode unit and the first electrode produced in Example 15 is attached.

Using this electrolyzer, electrolysis was performed at a flow rate of 2 L / min, a voltage of 3.9 V, and a current of 20 A, hypochlorous acid water was supplied on the first electrode (anode) 20 side, and hydrogen was supplied on the second electrode (cathode) 22 side. And produces aqueous sodium hydroxide. The production efficiency of hypochlorous acid is 94% and the pH is 2.5.

  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.

The invention described in the claims at the beginning of the application of Japanese Patent Application No. 2015-018781 will be appended below.

[1]
An electrode 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, wherein the plurality of through holes are formed from one end of the electrode to the other. An electrode whose aperture ratio gradually increases along the direction toward the end.

[2]
When the percentage of the opening area per unit area in each region divided into two or more from one end to the other end of the electrode is defined as the opening ratio, the first opening ratio of the first region, the first region, The electrode according to [1], wherein the ratio of the second aperture ratio of the different second region is in the range of 1: 1.05 to 1:10.

[3]
The electrode according to any one of [1] and [2], wherein an opening area of the through hole on the first surface side is 0.01 mm ² to 4 mm ² .

[4]
The electrode according to any one of [1] to [3], wherein the opening area of the through hole on the second surface side is 10 times or less than the opening area of the through hole on the first surface side.

[5]
The electrode according to any one of [1] to [4], wherein the length of the electrode in the longitudinal direction is from 5 cm to 100 cm.

[6]
A plurality of first recesses opening in the first surface; and a plurality of second recesses opening in the second surface and having a larger opening area than the first recess;
The electrode according to any one of [1] to [5], wherein at least a part of the through hole communicates the first recess and the second recess.

[7]
The electrode according to [6], wherein an opening area of the second recess is 1-1600 mm ² .

[8]
The electrode according to [6] or [7], wherein the second recess is connected from one end to the other end of the electrode excluding a seal portion.

[9]
The electrode according to [6], wherein the first recess is connected from one end to the other end of the electrode excluding a seal portion.

[10]
The electrode according to any one of [6] to [9], wherein the first recess and the second recess are orthogonal to each other.

[11]
The electrode according to any one of [6] to [9], wherein the first recess and the second recess are parallel to each other.

[12]
A first electrode comprising the electrode according to any one of [1] to [11],
A porous 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 porous diaphragm and the second electrode.
[13]
An electrolytic apparatus comprising: an electrolytic cell; the electrode unit according to [1] or [2] incorporated in the electrolytic cell; a first electrode chamber partitioned by the electrode unit; and a second electrode chamber.

[14]
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 [1] or [3], further comprising a line for taking out alkaline electrolyzed water from the cathode chamber.

[15]
The electrolysis apparatus according to [13] or [14], wherein a direction from one end to the other end of the first electrode is a direction along a flow direction in the first electrode chamber.

[16]
The electrolysis apparatus according to [13] or [14], wherein a direction from one end to the other end of the first electrode is a direction opposite to a flow direction in the first electrode chamber.

[17]
When the percentage of the opening area per unit area in each region divided into two or more from one end to the other end of the first electrode is defined as the opening ratio, the region in the first electrode chamber is upstream from the region in the flow direction. The electrolytic device according to [13] or [14], wherein the downstream area has a large aperture ratio.

[18]
When the percentage of the opening area per unit area in each region divided into two or more from one end to the other end of the first electrode is defined as the opening ratio, the region in the first electrode chamber is upstream from the region in the flow direction. The electrolytic device according to [13] or [14], in which the aperture ratio in the downstream region is small.

[19]
The electrolytic cell is capable of generating a flow by natural convection, and a direction from one end to the other end of the first electrode is a direction from an upper part to a lower part of the first electrode chamber [13]. Electrolyzer.

[20]
The electrolytic cell can generate a flow by natural convection, and a direction from one end to the other end of the first electrode is a direction from a lower part to an upper part of the first electrode chamber [13]. Electrolyzer.

  DESCRIPTION OF SYMBOLS 10 ... Electrolytic apparatus, 11 ... Electrolytic cell, 12, 12 ', 112 ... Electrode unit, 14 ... Partition, 16 ... Anode chamber, 18 ... Cathode chamber, 19 ... Intermediate chamber (electrolyte chamber), 20, 20', 120 ... 1st electrode (anode), 21, 21 ', 23, 23', 121, 123 ... Base material, 22, 22 ', 122 ... 2nd electrode (counter electrode, cathode), 21a, 21a', 23a, 23a ', 121a, 123a ... first surface, 21b, 21b', 23b, 23b ', 121b, 123b ... second surface, 24, 27 ... porous diaphragm, 25 ... holder, 26, 26a, 26b ... diaphragm, 28 ... Catalyst layer, 30 ... Power source, 32 ... Ammeter, 34 ... Voltmeter, 40, 44, 50, 63 ... First recess, 42, 46, 52, 62 ... Second recess, 43, 53, 61 ... Through hole 50 ... resist film, 60 ... bridge

Claims (20)

A first surface, a second surface located on the opposite side of the first surface, a plurality of first recesses opening in the first surface, and an opening area that is open in the second surface and larger than the first recess. A plurality of second recesses, and a first electrode having a plurality of through holes communicating the first recess and the second recess,
A second electrode provided opposite to the first surface of the first electrode;
An electrode unit comprising a porous diaphragm disposed on the first surface;
The through hole includes a curved portion and a straight portion, and a curvature radius r of the curved portion is from 0.005 mm to 0.5 mm, and an opening area thereof is from 0.05 mm ² to 2 mm ² .   A plurality of through holes are formed in one second recess, and the area of the through hole formed in the central region of the second recess is larger than that of the through hole formed in the peripheral region of the second recess. The electrode unit according to claim 1 which is larger than an area.   The electrode unit according to claim 1 or 2, wherein a curvature radius r of the bent portion of the through hole is from 0.01 mm to 0.3 mm. The electrode unit according to any one of claims 1 to 3, wherein an opening area of the through hole is 0.1 mm ² to 1.5 mm ² .   The electrode unit according to any one of claims 1 to 4, wherein a radius of curvature r of the bent portion of the through hole is 0.02 mm to 0.2 mm. The electrode unit according to any one of claims 1 to 5, wherein an opening area of the through hole is 0.2 mm ² to 1 mm ² .   The electrode unit according to claim 1, further comprising a structure for holding an electrolytic solution between the first electrode and the second electrode.   The electrode unit according to any one of claims 1 to 7, wherein the first surface includes the first concave portion and a flat portion other than the first concave portion.   The electrode unit according to claim 8, wherein the flat portion has a surface roughness of 0.01 μm to 3 μm.   The electrode unit according to claim 1, wherein the porous diaphragm contains an inorganic oxide.   The electrode unit according to any one of claims 1 to 10, wherein the porous diaphragm is a multilayer film including a plurality of porous films having different pore diameters.   The electrode unit according to claim 1, wherein an electrically insulating film that does not allow liquid to permeate is formed on a part of the surface of the electrode.   A first catalyst layer made of an electrocatalyst provided between the first electrode and the porous diaphragm; and a surface of the first electrode opposite to the first catalyst layer; The electrode unit according to any one of claims 1 to 12, further comprising a second catalyst layer having a different amount per unit area from the catalyst layer. 14. The electrode unit according to claim 1, wherein an opening area of the second recess is from 1 mm ² to 1600 mm ² .   The electrode unit according to any one of claims 1 to 14, wherein the second recess is connected from one end to the other end of the electrode excluding the seal portion.   The electrode unit according to any one of claims 1 to 15, wherein the first recess is connected from one end to the other end of the electrode excluding the seal portion.   The electrode unit according to claim 15 or 16, wherein the first recess and the second recess are orthogonal to each other.   The electrode unit according to claim 15 or 16, wherein the first recess and the second recess are parallel to each other.   An electrolysis apparatus comprising the electrode unit according to any one of claims 1 to 18, a power source for applying a voltage to the electrode, and a control device.   An electrolytic cell incorporating the electrode unit, a line for introducing an electrolyte containing chlorine ions into the electrolytic cell, a line for extracting hypochlorous acid water from the electrolytic cell, and a line for extracting alkaline water from the electrolytic cell are further provided. The electrolyzer according to claim 19.

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