WO2016042802A1

WO2016042802A1 - Electrode unit, electrolytic bath provided with electrode unit, and electrolysis device

Info

Publication number: WO2016042802A1
Application number: PCT/JP2015/056547
Authority: WO
Inventors: 内藤　勝之; 典裕吉永; 梅　武; 富松　師浩; 亮介八木; 横田　昌広; 英男太田
Original assignee: 株式会社東芝
Priority date: 2014-09-19
Filing date: 2015-03-05
Publication date: 2016-03-24
Also published as: US20160186336A1; CN106661744A; JPWO2016042802A1; JP6407963B2

Abstract

This electrode unit of an electrolysis device is provided with: a first electrode 20 comprising a first surface, a second surface positioned opposite of the first surface, multiple first holes opening to the first surface, and multiple second holes opening to the second surface and having a greater opening area than the first holes, wherein multiple first holes communicate with a single second hole; a second electrode 22 provided opposite of the first surface of the first electrode; and a continuous porous film 24 arranged between the first electrode and the second electrode and covering the first surface of the first electrode.

Description

Electrode unit, electrolytic cell including electrode unit, and electrolysis apparatus

Embodiment described here is related with an electrode unit, an electrolytic cell provided with this electrode unit, and an electrolysis device.

In recent years, electrolyzers that electrolyze water to produce electrolyzed water having various functions, such as alkaline ionized water, ozone water, or hypochlorous acid water, have been provided. Among electrolyzed water, hypochlorous acid water has an excellent sterilizing power and is safe for the human body and approved as a food additive.

As an electrolysis apparatus, for example, an electrolyzed water generation apparatus having a three-chamber type electrolytic cell 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 electrolyzer, for example, salt water is passed through the intermediate chamber, and water is circulated through the anode chamber and the cathode chamber, respectively. By electrolyzing the salt water in the intermediate chamber at the cathode and the anode, hypochlorous acid water is generated from the chlorine gas generated at the anode, and sodium hydroxide water is generated in the cathode chamber. The produced hypochlorous acid water is used as sterilizing / disinfecting water, and sodium hydroxide water is used as washing water.

In the three-chamber type electrolytic cell, the anion exchange membrane is easily deteriorated by chlorine or hypochlorous acid. Further, when the porous electrode and the ion exchange membrane (electrolyte membrane) are brought into close contact with each other, stress tends to concentrate on the edge portion of the hole of the electrode, and the membrane such as a thin electrolyte membrane having a low mechanical strength tends to deteriorate. Therefore, a technique has been proposed in which a non-woven fabric with an overlap or a cut is inserted between the porous electrode and the electrolyte membrane to reduce the deterioration of the electrode due to chlorine.

JP 2014-101549 A JP 2006-322053 A

However, when a porous film such as a non-woven fabric is sandwiched between the electrode and the electrolyte film, stress is applied to the porous film, resulting in a distribution in the film thickness of the porous film. That is, the film thickness of the porous film is not uniform. This porous film having a non-uniform thickness causes unevenness in the electrolytic reaction, resulting in a decrease in reaction efficiency of the electrolysis apparatus and deterioration of the electrolyte film.
The problem to be solved by the present invention is to provide an electrode unit, an electrolytic cell, and an electrolyzer having high reaction efficiency and a long life.

According to the embodiment, the electrolysis apparatus includes an electrode unit. The electrode unit has a first surface, a second surface located opposite to the first surface, a plurality of first holes opened in the first surface, and an opening in the second surface, A first electrode having a plurality of second hole portions having an opening area larger than that of the first hole portion, the plurality of first hole portions communicating with one second hole portion, and the first electrode A second electrode provided opposite to the first surface of the first electrode, and a continuous porous film disposed between the first electrode and the second electrode and covering the first surface of the first electrode. I have.

FIG. 1 is a cross-sectional view showing an electrolysis apparatus according to the first embodiment. FIG. 2 is a cross-sectional view showing an electrode unit of the electrolysis apparatus according to the first embodiment. FIG. 3 is an exploded perspective view of the electrode unit. FIG. 4 is a cross-sectional view showing an electrode manufacturing process. FIG. 5 is a cross-sectional view showing an electrode unit of the electrolysis apparatus according to the second embodiment. FIG. 6 is a perspective view showing electrodes of an electrode unit according to the second embodiment. FIG. 7 is a cross-sectional view showing an electrode unit of an electrolysis apparatus according to a third embodiment. FIG. 8 is a perspective view showing electrodes of an electrode unit according to the fourth embodiment. FIG. 9 is a cross-sectional view showing an electrolyzer according to a fifth embodiment. FIG. 10 is a cross-sectional view of an electrolysis apparatus according to a sixth embodiment. FIG. 11 is a cross-sectional view showing an electrode unit according to a sixth embodiment. FIG. 12 is a perspective view showing a first electrode and a second electrode according to a modification. FIG. 13 is a cross-sectional view schematically showing a porous film made of a film containing an inorganic oxide having pores that are irregular in a plane or three-dimensionally. FIG. 14 is a cross-sectional view schematically showing a porous film composed of a laminated film.

Hereinafter, various embodiments will be described with reference to the drawings. In addition, the same code | symbol shall be attached | subjected to a common structure through embodiment, and the overlapping description is abbreviate | omitted. In addition, each drawing is a schematic 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 electrodes are drawn on a plane, but may be curved in accordance with the shape of the electrode unit or may be cylindrical.

(First embodiment)
FIG. 1 is a diagram schematically showing an electrolysis apparatus according to the first embodiment. The electrolysis apparatus 10 includes, for example, a two-chamber electrolysis tank 11 and an electrode unit 12 disposed in the electrolysis tank 11. The electrolytic cell 11 is formed in a flat rectangular box shape, and the inside thereof is partitioned into two chambers, an anode chamber 16 and a cathode chamber 18, by a partition wall 14 and an electrode unit 12.

The electrode unit 12 is provided between a first electrode (anode) 20 positioned in the anode chamber 16, a second electrode (counter electrode, cathode) 22 positioned in the cathode chamber 18, and the first and second electrodes. A porous membrane 24 and a diaphragm 26.

The electrolysis apparatus 10 includes a power source 30 for driving the first and

second electrodes

20 and 22 of the electrode unit 12, an ammeter 32, a voltmeter 34, and a control device 36 for controlling them. 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.

Next, the electrode unit 12 will be described in detail. 2 is a cross-sectional view of the electrode unit, and FIG. 3 is an exploded perspective view of the electrode unit.
As shown in FIGS. 2 and 3, 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 base material 21 has a first surface 22a and a second surface 22b facing the first surface 22a substantially in parallel. The distance between the first surface 22a and the second surface 22b, that is, the plate thickness of the substrate 21 is formed at T1. The first surface 22 a faces the porous film 24, and the second surface 22 b faces the anode chamber 16.

A plurality of, for example, square first holes 40 are formed in the first surface 22a of the base material 21 and open to the first surface 22a. A plurality of second holes 42 are formed in the second surface 22b and open to the second surface 22b. The opening area of the second hole portion 42 is formed larger than the opening area of the first hole portion 40. One side R1 of the opening of the first hole 40 on the porous membrane 24 side is smaller than, for example, one side R2 of the opening of the square second hole 42, and the number of holes is the same as that of the first hole 40. More than the second holes 42 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 the present embodiment, T2 <T3.

In the present embodiment, the second holes 42 are formed, for example, in a square shape, and are arranged in a matrix on the second surface 22b. The peripheral wall that defines each second hole 42 is formed by a tapered surface 42a or a curved surface that widens the hole from the bottom of the hole toward the opening, that is, toward the second surface 22b. May be. The interval between the adjacent second hole portions 42, that is, the width of the linear portion of the electrode is set to W2. The second hole portion 42 is not limited to a rectangular shape, and may have other various shapes. Further, the second hole portions 42 are not limited to regular, and may be formed side by side at random.

A smaller opening of the first hole portion 40 is preferable in order to make the pressure uniform, but a certain size is necessary to inhibit material diffusion, and one side of the square opening is 0.1 to 2 mm. Preferably, it is 0.3 to 1 mm. As the opening, various shapes such as a square, a rectangle, a rhombus, a circle, and an ellipse can be used. The vertices of squares, rectangles and rhombuses may be rounded. The opening area is preferably 0.01 to 4 mm ² which is the same as the square opening area. 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 . The ratio (opening ratio) of the opening area to the electrode area including the opening is preferably 0.05 to 0.5, more preferably 0.1 to 0.4, and further preferably 0.15 to 0.3. If the aperture ratio is too small, it will be difficult to outgas. If the aperture ratio is too large, the electrode reaction is hindered.

The first hole 40 is, for example, formed in a square shape, and is provided side by side in a matrix on the first surface 22a. The peripheral wall that defines each first hole 40 is formed by a tapered surface 40a or a curved surface that widens the opening from the bottom of the hole toward the opening, that is, toward the first surface 22a. Also good. In the present embodiment, a plurality of, for example, nine first hole portions 40 are provided to face one second hole portion 42, communicate with the second hole portion 42, and penetrate the base material 21. Yes. The interval W1 between the adjacent first hole portions 40 is set to be smaller than the interval W2 between the second hole portions 42. Thereby, the number density of the 1st hole 40 in the 1st surface 22a is sufficiently larger than the number density of the 2nd hole 42 in the 2nd surface 22b.

Various shapes such as a square, a rectangle, a rhombus, a circle, and an ellipse can be used for the opening of the second hole portion 42. A larger opening diameter of the second hole portion 42 is preferable in order to improve gas escape, but it cannot be so large because electric resistance increases. In the case of a square opening, one side is preferably 1 to 40 mm, more preferably 2 to 30 mm, and still more preferably 3 to 20 mm. As the opening, various shapes such as a square, a rectangle, a rhombus, a circle, an ellipse and the like can be used, but the opening area is preferably 1 to 1600 mm ² which is the same as the opening area of the square. 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 and connects from one end of the electrode to the other is also possible, such as a rectangle or an ellipse.

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. Depending on the electrolytic reaction, it is preferable to form an electrolytic catalyst (catalyst layer) on the first surface and the second surface of the electrode. In the case of the anode, it is preferable to use a noble metal catalyst such as platinum or an oxide catalyst such as iridium oxide as the base material itself. The amount per unit area of the electrocatalyst may be different on both surfaces of the electrode. Thereby, a side reaction etc. can be suppressed.

The 1st hole part 40 may be formed not only regularly but in a line. Furthermore, not only the structure which all the 1st hole parts 40 are connected to the 2nd hole part 42 but the 1st hole part which is not connected to the 2nd hole part 42 may be included. That is, there may be a first hole 40 that is not in communication with the anode chamber 16. For example, as shown in FIG. 12, the

first holes

40 and 44 have a rectangular shape extending from the vicinity of one end of the electrode to the vicinity of the other end, and a plurality of opening portions 41 a communicating with the

second holes

42 and 46 therein, 45a may be arranged with a certain interval. Further, only a part of the holes of the

first holes

40 and 44 may be connected to the

second holes

42 and 44. The

first holes

40 and 44 that are not in communication with the

second holes

42 and 44 have an effect of increasing the electrode area.
Of the plurality of

first hole portions

40 and 44, the first hole portion having an opening area of 0.01 mm ² to 4 mm ² is preferably 85% or more, more preferably 90% or more of all the first hole portions. More preferably, it is 95% or more.

The first electrode 20 having the above-described configuration can be produced by, for example, an etching method using a mask. FIG. 4 shows an outline of the manufacturing method. As shown in FIGS. 4A and 4B, a single flat substrate 21 is prepared, and resist

films

50 a and 50 b are applied to the first surface 22 a and the second surface 22 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. 4 (d), the first surface 22a and the second surface 22b of the base material 21 are wet-etched with a solution through the

masks

52a and 52b, so that the plurality of first holes 40 and the plurality of first holes 40 and the plurality of first holes 40 and the plurality of first holes The second hole 42 is formed. Thereafter, the first electrode 20 is obtained by removing the

masks

52a and 52b.

The taper of the first and

second holes

40 and 42 and the shape of the curved surface can be controlled by the material of the base material 21 and the etching conditions. The depth of the first hole 40 is T2, and the depth of the second hole 42 is T3. As described above, the first and second holes are formed so that T2 <T3. In the etching, both surfaces of the base material 21 may be etched simultaneously, or one surface may be etched. The type of etching is not limited to wet etching, and dry etching or the like may be used. Further, the first electrode 20 can be manufactured not only by etching but also by processing such as laser or precision cutting.

As shown in FIGS. 1 to 3, according to the present embodiment, the second electrode (counter electrode) 22 is configured in the same manner as the first electrode 20. That is, the second electrode 22 has a porous structure in which a large number of through holes are formed in the base material 23 made of, for example, a rectangular metal plate. The base material 23 has a first surface 23a and a second surface 23b positioned substantially parallel to the opposite side of the first surface 23a. The first surface 23 a faces the diaphragm 26, and the second surface 23 b faces the cathode chamber 18.

A plurality of first holes 44 are formed in the first surface 23a of the base material 23 and open to the first surface 23a. A plurality of second holes 46 are formed in the second surface 23b and open to the second surface 23b. The opening area of the first hole 44 on the side of the diaphragm 26 is smaller than the opening area of the second hole 44, and the number of holes is larger in the first hole 44 than in the second hole 46. Has been. The depth of the first hole 44 is formed to be smaller than the depth of the second hole 46.

A plurality of, for example, nine first hole portions 44 are provided to face one second hole portion 46, communicate with the second hole portion 46 and penetrate the base material 23. The interval between the adjacent first hole portions 44 is set to be smaller than the interval between the second hole portions 46. Thereby, the number density of the 1st hole 44 in the 1st surface 23a is sufficiently larger than the number density of the 2nd hole 46 in the 2nd surface 23b.

The porous film 24 and the diaphragm 26 are sandwiched between the first surface 22a of the first electrode 20 and the first surface 23a of the second electrode 22. The continuous porous film 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 22a. As the porous film 24, a non-woven fabric, cloth, a porous film formed by a sol-gel method can be used, and various materials can be used. Porous membranes are chemically stable, especially resistant to chlorine, hypochlorous acid and oxygen, resistant to acidity and alkalinity, and in the case of polymers when used for food processing, etc. In the case where the monomer or the like does not dissolve above the legal value, or in the case of an inorganic substance, it is necessary that the heavy metal ion does not dissolve beyond the legal value. Mechanically, when a porous film is used alone without a backing material, ease of handling is important, and the film thickness is preferably 20 to 500 μm. When the porous film is directly formed on the electrode, it may be thin, but a film thickness of 50 nm or more is preferable in order to obtain the properties as a porous film. Among these porous membranes, a polymer membrane containing a fluorine atom or a chlorine atom in the main chain, a glass cloth, or a membrane containing an inorganic oxide having irregular continuous pores is particularly chemically. It is stable and preferable. Teflon is particularly preferable as the polymer film. Inorganic oxides may contain hydroxides, alkoxides, oxyhalides, and hydrates. When an inorganic oxide is produced through hydrolysis of a metal halide or metal alkoxide, it tends to be a mixture of these depending on the post-treatment temperature. A polymer film, a glass cloth, or an inorganic oxide may be combined, for example, a polymer film or a glass cloth may be coated with an inorganic oxide. As shown in FIG. 13, in the case where a film containing an inorganic oxide having pores that are irregular in a plane or three-dimensionally is used as the porous film 24, the porous film 24 can also serve as the diaphragm 26. That is, the diaphragm 26 can be omitted.

As shown in FIG. 14, the porous film 24 may be a laminated film of a plurality of

porous films

27a and 27b having different pore diameters. In this case, by making the pore diameter of the porous membrane 27b located on the diaphragm 26 side larger than the pore diameter of the porous membrane 27a located on the first electrode 20 side, the movement of ions is facilitated and the pores of the electrode The stress concentration due to can be reduced. This is because the larger the opening on the diaphragm 26 side, the easier the ion movement by diffusion. When the electrode 20 is used as an anode, the anion is easily attracted to the electrode even if the hole diameter on the electrode 20 side is small because of the positive potential. On the contrary, if the pore diameter on the electrode 20 side is large, the generated chlorine or the like tends to diffuse to the porous membrane side.

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

As shown in FIGS. 2 and 3, the diaphragm 26 is formed in, for example, a rectangular shape having substantially the same dimensions as the first electrode 20, and is disposed between the first surface 23 a of the second electrode 22 and the porous film 24. Has been. The diaphragm 26 is in close contact with the entire surface of the first surface 23 a of the second electrode 22, and is further in close contact with the porous film 24.

The diaphragm 26 located between the first and

second electrodes

20 and 22 is a film that allows ions and / or liquids to pass therethrough. As the diaphragm 26, various electrolyte membranes and porous membranes having nanopores can be used. As the electrolyte membrane, a polymer electrolyte membrane, for example, a cation exchange solid polymer electrolyte membrane, specifically, a cation exchange membrane, an anion exchange membrane, or a hydrocarbon membrane can be used. . Examples of the cation exchange membrane include NAFION (AI DuPont: Trademark) 112, 115, 117, Flemion (Asahi Glass Co., Ltd .: Trademark), ACIPLEX (Asahi Kasei Corporation: Trademark), Gore Select (W. El Gore and Associates). Company: Trademark). Examples of the anion-exchange membrane include A201 manufactured by Tokuyama Corporation. Porous membranes with nanopores include porous ceramics such as porous glass, high quality alumina, porous titania, porous zeolite, porous zirconia, porous polyethylene, porous propylene, porous teflon, porous polyimide, etc. There are porous polymers.

By pressing the porous film 24 and the diaphragm 26 between the first electrode 20 and the second electrode 22 configured as described above, the first electrode 20 and the porous film 24 are pressed. The electrode unit 12 is obtained by contacting the diaphragm 26 with the porous membrane 24 and the second electrode 22.

As shown in FIG. 1, the electrode unit 12 is disposed in the electrolytic cell 11 and attached to the partition wall 14. The 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 direction which each member which comprises this may contact becomes a horizontal direction, for example. The anode 20 of the electrode unit 12 is disposed facing the anode chamber 16, and the cathode 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 electrode unit 12 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 35. 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. The electrolyzer 10 of this embodiment preferably electrolyzes an electrolyte containing chloride ions.

According to the electrolytic apparatus and the electrode unit configured as described above, in the first electrode 20, the diameter (opening area) of the first hole portion 40 formed in the first surface 22a on the porous membrane 24 side is set to the second. By making it smaller than the diameter (opening area) of the hole 42 and increasing the number density of the hole, the stress concentration acting on the porous film 24 from the first electrode 20 side can be reduced. By making the porous film 24 into a continuous film and abutting the entire surface of the first surface 22a of the first electrode 20, the pores of the first electrode 20 are covered with the porous film 24, and the first electrode 20 and the diaphragm 26 are covered. Can be easily maintained over the entire surface. That is, it is possible to prevent a distribution from occurring in the film thickness of the porous film 24 and to maintain the film thickness of the porous film 24 uniform. Thereby, it is possible to uniformly generate the electrolytic reaction uniformly, and to improve the reaction efficiency of the electrolytic device and prevent the electrolyte membrane from being deteriorated.

Further, the contact angle between the first hole 40 and the porous film 24 is obtuse by making the first hole 40 of the first electrode 20 tapered or curved so that the first surface side of the electrode becomes wider. Thus, the stress concentration from the first electrode 20 side to the porous film 24 can be further reduced. The first surface 22a of the first electrode 20 on the porous membrane 24 side is preferably substantially flat except for the recess. The recess may be the first hole described above or a recess described later.

By increasing the opening area of the second hole portion 42 formed on the second surface 22b of the first electrode 20 and decreasing the number density, the width W2 of the linear portion between the second hole portions 42 is sufficiently increased. Can be thickened. Thereby, while maintaining the mechanical strength of the 1st electrode 20 high, reduction of an electrical resistance can be aimed at.
From the above, according to the first embodiment, an electrode unit and an electrolysis apparatus having high reaction efficiency and a long life can be obtained.
In the first embodiment, the second electrode 22 is not limited to the electrode having the first hole and the second hole having different diameters, and may be a flat electrode having no through hole. . Or it is good also as an electrode which formed the through-hole of the same diameter in the 1st surface and the 2nd surface in the electrode base material. The second electrode 22 and the diaphragm 26 may be in contact with each other, or another component may be inserted therebetween.

Next, an electrolysis device and an electrode unit according to another embodiment will be described. In other embodiments described below, the same parts as those in the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted, and the parts different from those in the first embodiment. Will be described in detail.

(Second Embodiment)
FIG. 5 is a sectional view showing an electrode unit of the electrolysis apparatus according to the second embodiment, and FIG. 6 is a perspective view showing an electrode.
According to the second embodiment, in the electrode unit 12, the first surface 22a of the first electrode 20 is formed flat, and the first holes 40 described above are formed on the first surface 22a. The first hole 40 penetrates the base material 21. The first electrode 20 has a plurality of recesses 54 formed on the first surface 22 a, that is, recesses that do not penetrate the base material 21. The concave portion 54 is formed by, for example, a continuous groove extending between the plurality of first hole portions 40. Or the recessed part 54 is good also as many independent dot-shaped recessed parts.
The porous film 24 is provided in close contact with the first surface 22 a of the first electrode 20. The porous membrane 24 faces and closes the first hole 40 and the recess 54.

The first surface 22 a of the first electrode 20 is preferably flat except for the first hole 40 and the recess 54. By providing the concave portion 54, the electrode area can be increased and a flow path for removing the generated gas can be provided. The stress concentration on the porous film 24 can be further reduced by making the first surface 22 a of the first electrode 20 substantially flat except for the concave portion 54. Although it varies depending on the film thickness of the porous film 24, the flatness and average roughness of the first surface 22a are preferably 10% or less of the average film thickness of the porous film 24, and more preferably 5% or less. 2% or less is more preferable. The average roughness can be examined by cross-sectional SEM observation.
In addition to the first electrode 20, a plurality of recesses may be provided on the first surface 23 a of the second electrode 22.

(Third embodiment)
FIG. 7 is a cross-sectional view showing an electrode unit of the electrolysis apparatus according to the third embodiment. In the third embodiment, an electrical insulating film 56 that does not transmit liquid is formed on at least a part of the surface of the first electrode 20. In the first electrode 20, on the first surface 22a that is in wide contact with the porous membrane 24 on the side of the diaphragm 26, it is difficult to discharge a gas such as chlorine generated by the reaction, so that the generated gas tends to deteriorate the diaphragm 26. Therefore, by covering the region where the first hole 40 is not formed in the first surface 22a with the insulating film 56, the generation of the reaction gas in these regions is suppressed and the deterioration of the diaphragm 26 is prevented. Can do. In the present embodiment, the insulating films 56 are provided on both surfaces of the wide linear portion (width W2) of the first electrode 20.

However, the reaction area of the first electrode 20 is reduced by providing the insulating film 56. Therefore, it is desirable that a sufficient reaction of the first electrode 20 occurs in a portion where the generated gas is easily released. Further, the second surface 22b of the first electrode 20 located on the opposite side of the diaphragm 26 may be covered with an electrical insulating film 57. When such an electrode unit 12 is used in a three-chamber electrolytic cell, multiple reactions on the second surface 22b side can be reduced. Note that a part of the insulating film may protrude in the cross-sectional direction of the electrode.

(Fourth embodiment)
FIG. 8 is a perspective view showing electrodes of the electrode unit of the electrolysis apparatus according to the fourth embodiment. In 4th Embodiment, in the 1st electrode 20, the space | interval W3 between the 1st hole parts 40 formed in the center part of the electrode is the space | interval W1 between the 1st hole parts 40 formed in the peripheral part of an electrode. Is set larger than. Thereby, the aperture ratio at the center of the first electrode 20 (ratio of the aperture area to the electrode area including the aperture) is smaller than the aperture ratio at the peripheral edge of the first electrode 20. Therefore, the electrical resistance of the central portion of the first electrode 20 can be made smaller than that of the peripheral portion, and even when power is supplied to the electrode from the peripheral portion of the electrode, an increase in voltage at the central portion of the electrode can be reduced. . As shown in FIG. 8, the opening area of the first hole 40 formed in the central portion of the first electrode 20 is made smaller than the opening area of the first hole 40 provided in the periphery, or the number thereof is set to be smaller. By reducing the aperture ratio, the aperture ratio can be reduced.

(Fifth embodiment)
FIG. 9 is a cross-sectional view showing an electrolysis apparatus according to the fifth embodiment. In the fifth embodiment, the electrolytic cell 11 of the electrolytic device 10 is configured as a one-chamber electrolytic cell having a single electrolytic chamber 17. The electrode unit 12 is disposed in the electrolysis chamber 17. The electrolysis chamber 17 may be connected with piping, a pump, and the like for supplying and discharging the electrolyte from the outside.

In the one-chamber type electrolytic cell 11, the second electrode (counter electrode) 22 of the electrode unit 12 is preferably formed in a porous structure like the first electrode 20. By using a porous structure, the electrode area can be increased.

(Sixth embodiment)
FIG. 10 is a cross-sectional view showing an electrolysis apparatus according to the sixth embodiment, and FIG. 11 is a cross-sectional view showing an electrode unit in the electrolysis apparatus.
As shown in FIG. 10, the electrolysis apparatus 10 includes a three-chamber type electrolytic cell 11 having an electrode unit 12. The electrolytic cell 11 is formed in a flat rectangular box shape, and the internal electrolytic chamber is composed of an anode chamber 16, a cathode chamber 18, and an intermediate chamber 19 formed between the electrodes by the partition wall 14 and the electrode unit 12. It is divided into rooms.

The electrode unit 12 is provided between a first electrode (anode) 20 positioned in the anode chamber 16, a second electrode (counter electrode, cathode) 22 positioned in the cathode chamber 18, and the first and second electrodes. Two

diaphragms

26a and 26b, a porous film 24a sandwiched between the first electrode 22 and the diaphragm 26a, and a porous film 24b sandwiched between the second electrode 22 and the diaphragm 26b. Have. The

diaphragms

26a and 26b face each other in parallel with a gap, and an intermediate chamber (electrolyte chamber) 19 for holding the electrolyte is formed between the

diaphragms

26a and 26b. 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

As shown in FIGS. 10 and 11, in the electrode unit 12, the first electrode 20 and the second electrode 22 are configured to have the same porous structure as that of the first embodiment described above. The continuous porous film 24a 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 22a. The continuous porous film 24b 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 these

porous membranes

24a and 24b, porous membranes formed by a nonwoven fabric, cloth, or sol-gel method can be used, and various materials can be used. Among these porous membranes, it is chemically stable to be a polymer membrane containing fluorine or chlorine atoms in the main chain, or a membrane containing glass cloth or an inorganic oxide having irregular continuous pores. It is preferable. The

porous films

24a and 24b can also serve as the

diaphragms

26a and 26b as long as the films contain an inorganic oxide having irregular pores. As the

porous films

24a and 24b, a laminated film of a plurality of porous films having different pore diameters may be used.

For example, the diaphragm 26 a is formed in a rectangular shape having substantially the same dimensions as the first electrode 20, and faces the first surface 22 a of the first electrode 20. A porous membrane 24a is sandwiched between the first surface 22a of the first electrode 20 and the diaphragm 26a, and is in close contact with the first electrode 20 and the diaphragm 26a.

For example, the diaphragm 26 b is formed in a rectangular shape having substantially the same dimensions as the second electrode 22, and faces the first surface 23 a of the second electrode 22. A porous membrane 24b is sandwiched between the first surface 23a of the second electrode 22 and the diaphragm 26b, and is in close contact with the second electrode 22 and the diaphragm 26b.

The

diaphragms

26a and 26b are membranes that allow ions and / or liquids to pass therethrough. As the

diaphragms

26a and 26b, the various electrolyte membranes and porous membranes having nanopores described in the first embodiment can be used.

Also in the sixth embodiment configured as described above, the same operational effects as those of the first embodiment described above can be obtained, and an electrode unit and an electrolysis apparatus having high reaction efficiency and a long life can be obtained.

Next, various examples and comparative examples will be described.
(Example 1)
The electrode base material 21 uses a flat titanium plate having a plate thickness T1 of 0.5 mm, and an electrode is produced by etching the titanium plate shown in FIG. Among the electrodes, the thickness (the first hole depth) T2 of the region including the small-diameter first hole 40 is 0.15 mm, and the thickness (second hole) of the region including the large-diameter second hole 42 is selected. Part depth) T3 is 0.35 mm. The first hole 40 has a square shape, and the apex of the square is rounded, but one side R1 of the square obtained by extrapolating the straight line portion is 0.57 mm, the second hole portion 42 is a square, and the one side R2 is 2 mm. . The width W1 of the linear portion formed between the adjacent first hole portions 40 is 0.1 mm, and the width W2 of the wide linear portion formed between the adjacent second hole portions 42 is 1.0 mm.

In advance, the electrode substrate 21 is treated at 80 ° C. for 1 hour in a 10 wt% oxalic acid aqueous solution. The surface on which the first hole 40 of the electrode substrate 21 is formed (first surface) by adjusting iridium chloride (IrCl ₃ .nH ₂ O) by adding 1-butanol to 0.25 M (Ir) After coating, drying and baking are performed. 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. The average roughness of the flat portion excluding the concave portion of the first electrode 20 is 1 μm from the measurement of AFM.
Moreover, the 2nd electrode (counter electrode, cathode) 22 is produced by sputter | spatterring platinum to the 1st surface in which the 1st hole part of the electrode base material mentioned above was formed.

The electrode unit 12 shown in FIG. 11 is produced using the obtained first and second electrodes. A201 manufactured by Tokuyama, which is an anion exchange membrane, is used as the diaphragm 26a, and NAFION (trademark) 117 is used as the diaphragm 26b. Glass cloth (thickness 75 μm) is used as the

porous films

24a and 24b. A porous polystyrene having a thickness of 5 mm is provided in the intermediate chamber (electrolytic solution chamber) 19 as a holding body 25 for holding the electrolytic solution. The first and second electrodes, the porous membrane, the partition walls, and the porous polystyrene are overlapped and fixed using a silicone sealant and screws to form an electrode unit 12. Using this electrode unit 12, the electrolytic cell 11 and the electrolysis apparatus 10 shown in FIG. 10 are produced.

The anode chamber 16 and the cathode chamber 18 of the electrolytic cell 11 are each formed of a vinyl chloride container in which straight channels are formed. A control device 36, a power source 30, a voltmeter 34, and an ammeter 32 are installed. Pipes and pumps for supplying water to the anode chamber 16 and the cathode chamber 18 are connected to the electrolytic cell 11, and saturated saline for circulating and supplying saturated saline 25 to the holder (porous polystyrene) 25 of the electrode unit 12. The tank, piping and pump are connected to the electrode unit.

Electrolysis is performed using the electrolysis apparatus 10 at a voltage of 5 V and a current of 1.5 A, and hypochlorous acid water is generated on the anode 20 side and sodium hydroxide water is generated on the cathode 22 side. 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)
Change the mask at the time of etching so that the first hole 40 in the central portion 1 × 1.4 cm of the 3 × 4 cm electrode base material is square, the one side R1 thereof is 0.7 mm, and the width W1 of the linear portion is 0.2 mm. The first electrode 20 is produced. The 2nd hole 42 is made into a square, and the one side is 2 mm. The center second hole includes 2 × 2 first holes. Other configurations are the same as in Example 1, and the electrode unit 12 and the electrolyzer 10 are produced.

Using this electrolyzer 10, electrolysis is performed at a voltage of 4.8 V and a current of 1.5 A, and hypochlorous acid water is generated on the anode 20 side and sodium hydroxide water is generated on the cathode 22 side. 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 the porous film, a nonwoven fabric made of polyvinylidene chloride is used instead of glass cloth. Other configurations are the same as those in the first embodiment, and the electrode unit 12 and the electrolysis apparatus 10 are manufactured.

Using this electrolyzer 10, electrolysis is performed at a voltage of 5.1 V and a current of 1.5 A, and hypochlorous acid water is generated on the anode 20 side and sodium hydroxide water is generated on the cathode 22 side. 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
As the porous film, a porous titanium oxide film having irregular pores is used instead of glass cloth. Other configurations are the same as those in the first embodiment, and the electrode unit 12 and the electrolysis apparatus 10 are manufactured.

Using this electrolyzer 10, electrolysis is performed at a voltage of 5.2 V and a current of 1.5 A, and hypochlorous acid water is generated on the anode 20 side and sodium hydroxide water is generated on the cathode 22 side. 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)
As the porous film, a non-woven fabric made of Teflon is used instead of glass cloth. Other configurations are the same as those in the first embodiment, and the electrode unit 12 and the electrolysis apparatus 10 are manufactured.

Using the electrolyzer 10, electrolysis is performed at a voltage of 5.0 V and a current of 1.5 A, and hypochlorous acid water is generated on the anode 20 side and sodium hydroxide water is generated on the cathode 22 side. 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)
An electrically insulating polyvinyl chloride is selectively applied to the wide linear portion (width W2) of the first electrode 20 manufactured in the same manner as in Example 1 using a screen printing method to form an insulating film. Other configurations are the same as in Example 1, and the electrode unit 12 and the electrolyzer 10 are produced.

Using this electrolyzer 10, electrolysis is performed at a voltage of 5.3 V and a current of 1.5 A to generate hypochlorous acid water on the anode 20 side and sodium hydroxide water on the cathode 22 side. 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 the same manner as in Example 1, a porous second electrode (counter electrode) 22 is produced. A porous glass film (film thickness 50 μm) is used as the diaphragm 26. A glass cloth (film thickness 75 μm) is used as the porous film 24. These are overlapped using a silicone sealant and screws to produce the electrode unit 12.

Using this electrode unit 12, the one-chamber electrolytic cell 11 and the electrolyzer 10 shown in FIG. 9 are produced. A control device 36, a power source 30, a voltmeter 34, and an ammeter 32 are installed, and a pipe and a pump for supplying saline to the electrolysis chamber 17 are installed. Electrolysis is performed at a voltage of 4.3 V and a current of 1.5 A using the electrolyzer 10 to generate sodium hypochlorite 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 8)
As the porous film, a polyphenylene sulfide porous film coated with a film containing titanium oxide is used instead of glass cloth. As the

diaphragms

26a and 26b, a polyphenylene sulfide film coated with the above-described film containing titanium oxide is also used. Other configurations are the same as those in the first embodiment, and the electrode unit 12 and the electrolysis apparatus 10 are manufactured.

Using this electrolyzer 10, electrolysis is performed at a voltage of 4.8 V and a current of 1.5 A, and hypochlorous acid water is generated on the anode 20 side and sodium hydroxide water is generated on the cathode 22 side. Even after 2000 hours of continuous operation, there is almost no increase in voltage or change in product concentration, and stable electrolytic treatment can be performed.

Example 9
Instead of using a polyphenylene sulfide porous film coated with a film containing titanium oxide, a glass nonwoven fabric (filter paper) coated with a film containing titanium oxide is used as the porous film. The other configuration is the same as in Example 8, and the electrode unit 12 and the electrolyzer 10 are produced.

Using this electrolyzer 10, electrolysis is performed at a voltage of 4.7 V and a current of 1.5 A, and hypochlorous acid water is generated on the anode 20 side and sodium hydroxide water is generated on the cathode 22 side. Even after 2000 hours of continuous operation, there is almost no increase in voltage or change in product concentration, and stable electrolytic treatment can be performed.

(Example 10)
Instead of using a polyphenylene sulfide porous film coated with a film containing titanium oxide, a glass nonwoven fabric (filter paper) coated with a film containing zirconium oxide is used as the porous film. The other configuration is the same as in Example 8, and the electrode unit 12 and the electrolyzer 10 are produced.

(Example 11)
Instead of using a polyphenylene sulfide porous film coated with a film containing titanium oxide as the porous film, a film further coated with a denser film containing zirconium oxide is used on the electrode side surface of the porous film. Except for this, the electrode unit 12 and the electrolyzer 10 are produced in the same manner as in Example 8.

Using the electrolyzer 10, electrolysis is performed at a voltage of 4.9 V and a current of 1.5 V, and hypochlorous acid water is generated on the anode 20 side and sodium hydroxide water is generated on the cathode 22 side. Even in continuous operation for 2000 hours, almost no voltage increase or product change is observed, and stable electrolytic treatment can be performed.

Example 12
Except for using a porous film made of a Teflon porous film coated with a film containing zirconium oxide instead of using a polyphenylene sulfide porous film coated with a film containing titanium oxide as a porous film. In the same manner as in FIG. 8, the electrode unit 12 and the electrolyzer 10 are produced.

Using the electrolyzer 10, electrolysis is performed at a voltage of 4.9 V and a current of 1.5 V, and hypochlorous acid water is generated on the anode 20 side and sodium hydroxide water is generated on the cathode 22 side. Even during continuous operation for 2500 hours, almost no voltage increase or product change is observed, and stable electrolytic treatment can be performed.

(Example 13)
The electrode base material 21 uses a flat titanium plate having a plate thickness T1 of 0.5 mm, and an electrode is produced by etching the titanium plate shown in FIG. Among the electrodes, the thickness (the first hole depth) T2 of the region including the small-diameter first hole 40 is 0.15 mm, and the thickness (second hole) of the region including the large-diameter second hole 42 is selected. Part depth) T3 is 0.35 mm. The 1st hole part 40 is made into a rhombus, and makes a long diagonal line 0.69mm and a short diagonal line 0.4mm. The 2nd hole 42 is made into a rhombus, a long diagonal is 6.1 mm, and a short diagonal is 3.5 mm. The width W1 of the linear portion formed between the adjacent first hole portions 40 is 0.15 mm, and the width W2 of the wide linear portion formed between the adjacent second hole portions 42 is 1 mm. Other configurations are the same as in Example 1, and the electrode unit 12 and the electrolyzer 10 are produced.

(Example 14)
The electrode base material 21 uses a flat titanium plate having a plate thickness T1 of 0.5 mm, and an electrode is produced by etching the titanium plate shown in FIG. Among the electrodes, the thickness (the first hole depth) T2 of the region including the small-diameter first hole 40 is 0.15 mm, and the thickness (second hole) of the region including the large-diameter second hole 42 is selected. Part depth) T3 is 0.35 mm. The first hole 40 is square, its one side R1 is 0.57 mm, the second hole 42 is rectangular, its long side is 40 mm, and its short side is 4 mm. The width W1 of the linear portion formed between the adjacent first hole portions 40 is 0.1 mm, and the width W2 of the wide linear portion formed between the adjacent second hole portions 42 is 1.0 mm. Other configurations are the same as in Example 1, and the electrode unit 12 and the electrolyzer 10 are produced.

Using this electrolyzer 10, electrolysis is performed at a voltage of 5.8 V and a current of 1.5 A, and hypochlorous acid water is generated on the anode 20 side and sodium hydroxide water is generated on the cathode 22 side. 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)
An electrolysis device is produced in the same manner as in Example 1 except that a continuous porous membrane is not used. Using this electrolyzer, electrolysis is performed at a voltage of 5 V and a current of 1.5 A, and hypochlorous acid water is generated on the anode side and sodium hydroxide water is generated on the cathode side. After 1000 hours of continuous operation, a significant increase in voltage and a decrease in product concentration are observed, and long-term stability is lacking.

(Comparative Example 2)
Instead of producing the electrode by etching, a through hole having a diameter of 1 mm is formed in the electrode substrate by punching, and an electrode having the same aperture ratio as that of the electrode of Example 1 is used. Other configurations are the same as those in the first embodiment, and an electrode unit and an electrolysis apparatus are manufactured.

Using this electrolyzer, electrolysis is performed at a voltage of 5.2 V and a current of 1.5 A, and hypochlorous acid water is generated on the anode side and sodium hydroxide water is generated on the cathode side. After 1000 hours of continuous operation, a significant increase in voltage and a decrease in product concentration are observed, and long-term stability is lacking.

The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
For example, the first electrode and the second electrode are not limited to a rectangular shape, and other various shapes can be selected. The first hole and the second hole of the first electrode are not limited to a square, and may be various other shapes such as a rectangle, a diamond, a circle, and an ellipse. The material of each constituent member is not limited to the above-described embodiments and examples, and other materials can be appropriately selected. The electrolytic cell of the electrode device is not limited to a 1 to 3 chamber type electrolytic cell, and can be applied to all electrolytic cells using electrodes. Electrolytes and products are not limited to salts and hypochlorous acid, and may be applied to various electrolytes and products.

Claims

A first surface, a second surface located opposite to the first surface, a plurality of first holes opened in the first surface, an opening in the second surface, and the first hole A plurality of second holes having a larger opening area than the first part, and a first electrode in which the plurality of first holes communicates with one second hole,
A second electrode provided opposite to the first surface of the first electrode;
A continuous porous membrane disposed between the first electrode and the second electrode and covering the first surface of the first electrode;
An electrode unit comprising:
The electrode unit according to claim 1, wherein an opening area of the first surface of the first hole portion is 0.01 to 4 mm 2 .
The electrode unit according to claim 1 or 2, wherein an opening area of the second surface of the second hole portion is 1 to 1600 mm 2 .
The electrode unit according to any one of claims 1 to 3, wherein the number density per unit area of the first hole is larger than the number density per unit area of the second hole.
The catalyst layer is formed on the first surface and the second surface of the first electrode, and the amount per unit area of the catalyst layer is different between the first surface and the second surface. The electrode unit according to item.
The electrode unit according to any one of claims 1 to 5, wherein the first hole portion is formed in a tapered surface shape or a curved surface shape in which the first surface side is widened.
The said 1st electrode has a recessed part formed in the said 1st surface, The said 1st surface is formed in flat except the said 1st hole and recessed part. 2. The electrode unit according to item 1.
The electrode unit according to claim 7, wherein the average roughness of the flat portion of the first electrode is 10% or less of the average film thickness of the porous film.
9. The first electrode according to claim 1, wherein the first electrode has an aperture ratio of a first hole located at a center portion of the first electrode smaller than an aperture ratio of a first hole located at a peripheral edge of the first electrode. The electrode unit according to any one of the above.
The electrode unit according to any one of claims 1 to 9, wherein an insulating film having an electrical insulation property that does not transmit liquid is formed on at least a part of the first surface of the first electrode.
The electrode unit according to any one of claims 1 to 10, wherein the second electrode has a porous structure including a plurality of through holes.
The electrode unit according to any one of claims 1 to 11, wherein the porous film is a polymer film containing a fluorine atom or a chlorine atom in the main chain.
The electrode unit according to any one of claims 1 to 11, wherein the porous film is a glass cloth.
The electrode unit according to any one of claims 1 to 11, wherein the porous film is a film containing an inorganic oxide having in-plane and sterically irregular pores.
The electrode unit according to any one of claims 1 to 14, wherein the porous film is a laminated film in which a plurality of porous films having different pore diameters are laminated.
A diaphragm provided between the first surface of the first electrode and the second electrode and transmitting at least one of ions and liquid; and the porous membrane includes a first surface of the first electrode The electrode unit according to claim 1, wherein the electrode unit is sandwiched between the diaphragm.
Two diaphragms disposed opposite to each other between the first electrode and the second electrode, and an electrolyte solution holding structure portion that is located between the two diaphragms and holds the electrolyte solution. Item 17. The electrode unit according to any one of Items 1 to 16.
An electrolytic cell comprising an electrolysis chamber and the electrode unit according to any one of claims 1 to 17 disposed in the electrolysis chamber.
An electrolytic cell having an electrolysis chamber, an electrode unit according to any one of claims 1 to 17 disposed in the electrolysis chamber, a power source for applying a voltage to the first electrode and the second electrode of the electrode unit, An electrolysis apparatus comprising:
The electrolysis apparatus according to claim 19, wherein the electrode unit electrolyzes an electrolyte containing chloride ions.