Catalyst electrode for zero-gap water electrolysis device and method for producing ozone water using said electrode

Abstract

To form an efficient flow of water on an electrode surface, and to improve an ozone generation efficiency by increasing contact points between a diamond catalytic electrode and an SPE membrane.SOLUTION: A catalytic electrode body is used for a water electrolysis apparatus, in which a waterway network is arranged on a flat working surface of a substrate made of a conductive material; and water to be treated is moved along the waterway network. On the catalytic electrode body, the waterway network includes multiple waterways which are formed as dents in the thickness direction; the waterway network has inlets for allowing water to flow in on the upstream side and outlets for allowing water to flow out on the downstream side regarding the movement of water; and a water flow path is assembled from the inlet to the outlet by a collaborative connection of the inclusive waterways.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a highly efficient electrode assembly for an electrolysis device, and in particular to an electrode assembly for a contact (zero-gap) type water electrolysis device for producing ozone water using an SPE (solid polymer electrolyte) membrane. [Background technology]

[0002] Ozone water, an aqueous solution of ozone gas, has a high bactericidal effect, but also has little effect on the human body; it does not irritate the skin when touched, and is safe even if it gets into the eyes or mouth. Therefore, it is used for sterilization and infection control in various facilities around the world, including medical institutions, food factories, and daycare centers.

[0003] Ozone gas can be easily produced by the anodic reaction in a water electrolysis cell. 3H2O → O3+ 6H + + 6e - 2H2O → O2+ 4H + + 4e - O2+ H2O → O3+ 2H + + 2e - Various electrode materials, electrolytic cell configurations, and methods have been developed with the aim of optimizing the current efficiency in this electrolytic reaction, improving ozone generation efficiency, and extending electrode life.

[0004] As a catalytic electrode material to promote the above reaction, diamond that has been made electrically conductive by incorporating boron (boron-doped diamond, BDD) is preferred due to its excellent chemical and dimensional stability. It is often used as an anode material by coating it in the form of a film on a corrosion-resistant metal substrate that is resistant to electrolysis, or by adhering particles to it.

[0005] For example, there are known examples of electrode structures in which BDD is coated onto a titanium plate or mesh by chemical vapor deposition (CVD), or BDD particles are fixed between titanium meshes. However, due to ease of handling and the reliability of ozone generation, it is more common to form a thin film of BDD by chemical vapor deposition (CVD) on a flat metal plate with multiple holes (Non-Patent Documents 1 and 2).

[0006] Meanwhile, a method has also been developed in which an electrolytic cell is constructed by placing an anode and a cathode facing each other in close contact (zero-gap) with an SPE membrane such as Nafion (trade name) sandwiched between them, and then immersing the cell in water and applying a potential (Patent Document 1). This cell structure has the advantage of a narrow reaction space, resulting in a short diffusion length of substances and rapid reaction. Specifically, since ozone, hydrogen peroxide, and various water electrolysis intermediate products (ions and radicals) are present near the electrode surface during water electrolysis, anodic oxidation proceeds efficiently, and it is known that, for example, during wastewater purification, the reaction between pollutants in the water and the oxidant proceeds quickly, achieving high purification efficiency.

[0007] The electrode reaction that generates ozone proceeds at the part of the electrode that comes into contact with water, particularly near the boundary between the BDD and SPE membrane, where a three-phase interface of gas, liquid, and solid phases is formed. In some cases, multiple small holes are formed in the electrode plate to allow water to penetrate or pass through, thereby expanding the contact area. It has also been reported that high current efficiency was achieved in an ozone generation reaction using an electrolysis device constructed by closely adhering a BDD-coated Ti plate anode and an SPE membrane (Non-Patent Document 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Re-Tabled Publication No. 2020 / 171238 (Patent No. 7010529) [Non-patent literature]

[0009] [Non-Patent Document 1] K. Arihara, et al. ElectroChem. Solid-State Lett., 9, D17 (2006) [Non-patent document 2] R&D Kobe Steel Technical Report 60 (1)Apr. 2010 Summary of the Invention [Problem to be solved by the invention]

[0010] In the electrolytic generation of ozone and other substances using a zero-gap electrolysis device with a BDD catalytic electrode and an SPE membrane, maximizing the area in contact with water between the diamond electrode and the SPE membrane is an important factor in optimizing operating conditions such as current efficiency. However, this cannot be said to be fully achieved with conventional electrode configurations, and there is room for improvement.

[0011] Conventional anodes include electrodes with a BDD supported on a titanium mesh or substrate. While mesh-based anodes ensure a sufficient supply of raw water because the treated water passes through the mesh, the metal mesh structure presents challenges in terms of adhesion between the BDD and the SPE membrane. Meanwhile, BDDs supported on a metal substrate ensure close adhesion to the SPE membrane, but the amount of raw water passing through the narrow gaps presents challenges. Therefore, while numerous small holes are provided in the substrate to allow for the supply of raw water, the formation of a three-phase interface is primarily limited to the circumferential area of ​​the small holes that contact the SPE membrane.

[0012] Therefore, an object of the present invention is to improve the efficiency of ozone generation per electrode area in such an electrolytic cell by expanding the reaction area that contributes to ozone generation. In particular, the present invention provides a diamond catalyst electrode in which an effective and clear water channel network is provided on the anode surface to form an efficient flow of water on the working surface and a three-phase interface is formed. Water and This increases the number of contact points with the SPE membrane, thereby improving the efficiency of ozone generation. [Means for solving the problem]

[0013] The present invention relates to an electrode body for an electrolytic cell for water treatment, in which a water channel network is provided on the flat working surface of a substrate made of a conductive material, and water to be treated is moved along the water channel network.The main feature of this invention is that the water channel network includes continuous water channels formed as recessed grooves in the thickness direction, and has an inlet on the upstream side for letting water in and an outlet on the downstream side for letting water out, allowing water to flow from the inlet to the outlet.

[0014] The electrode body of the present invention is intended to be mounted in a zero-gap electrolysis device and used for electrolytic generation of ozone water, etc. The manufacturing method basically includes the following steps. (1) The anode body, which is formed by bonding boron-doped diamond (BDD) to a corrosion-resistant metal substrate, is placed in close contact with and face-to-face with the SPE membrane, a cathode is placed on the back of the SPE membrane and immersed in water, and a water flow is generated along the electrode working surface. (2) Applying a potential between the two electrodes that can generate ozone ionizes the water in contact with the SPE membrane. (3) BDD generates ozone by an anodic reaction. (4) The generated ozone is dissolved in the surrounding water and collected. [Effects of the Invention]

[0015] In the present invention, a wide network of water channels is provided on the anode working surface, consisting of numerous channels connecting the inlet and outlet of raw water, and the edges of both banks of the channels in contact with the SPE membrane are used as the regions where a three-phase interface is formed, so that substantially the entire anode working surface can function as an effective ozone generation starting point. For example, parallel grooves (channels) 0.1 mm wide and 0.1 mm deep are formed at 0.1 mm intervals over the entire surface of a metal electrode substrate such as titanium or niobium, and a BDD thin film is formed on top of these to serve as water channels. By forming the grooves as water channels, three-phase interfaces are generated at the contact points between the diamond film, particles, and polymer electrolyte membrane present at the edges of the grooves, making it possible to essentially turn almost the entire surface of the electrode into a functional surface for ozone generation.

[0016] Furthermore, the electrode body of the present invention is capable of passing a large current at a low voltage, making it ideal as an electrode for producing ultra-high concentration ozone water, and it can also be used in a variety of applications in semiconductor processes. Furthermore, since it is possible to produce ultra-high concentration ozone water using tap water without causing electrolytic deposition of minerals, it can also be used to produce industrial treated water, such as in pre-treatment processes for plating, and can be used in a variety of equipment and processes involving water treatment. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is an explanatory view showing an example of an electrode assembly having a rectangular substrate and an active surface produced according to the present invention. [Figure 2] FIG. 2 is an explanatory diagram showing an example of an electrode assembly having a circular substrate and an active surface produced according to the present invention. [Figure 3] FIG. 3 is an enlarged explanatory view showing the shape of a water channel network (part) on the surface of an electrode body produced according to the present invention. [Figure 4] FIG. 4 is an explanatory diagram of the water channel network of the electrode body of the present invention used in an example of operation for comparison with the conventional configuration. [Figure 5] FIG. 5 is a graph showing current-voltage comparison in an example of operation using an electrode assembly of the present invention and a conventional configuration. DETAILED DESCRIPTION OF THE INVENTION

[0018] It is known that the ozone gas generation reaction on the anode surface proceeds in a three-phase interface region approximately 0.05 mm wide where the reaction field (water), the catalytic BDD electrode, and the SPE membrane meet. Therefore, in this invention, a water channel network consisting of multiple water channels is installed on the active surface of the anode, and the BDDs on both sides of the water channels that contact the SPE membrane are used as the starting points for ozone generation.

[0019] Such an increase in the three-phase interface makes it possible to reduce the resistance of the BDD catalyst portion, which brings about the following advantages, particularly in the ozone generation process, and is therefore of great practical value. - When operating at the same current density, the voltage can be reduced, which suppresses the electrolytic deposition of minerals at the cathode, enabling long-term operation. When operating at the same voltage, the current density can be increased, which increases the amount of ozone and hydrogen peroxide produced. This means that a large amount of ozone water can be produced with a small device. The actual electrodes will take on various shapes depending on the structure of the electrolysis device, but in any case, by providing multiple water channels connecting the inlet and outlet of the water to be treated, it is possible to increase the amount of functional water such as ozonated water and reduce water flow resistance.

[0020] In the operation of a zero-gap water electrolyzer, water to be treated is generally introduced between the closely attached working surface and the SPE membrane surface, and a gentle flow is provided so that the generated ozone and hydrogen can be dissolved and pass through. However, the electrode body of the present invention is particularly intended to maximize the three-phase interface reaction area where the reaction proceeds, and is provided with an electrode body having a water channel network that can guide the water to be treated and efficiently guide and discharge it outside the electrode body.

[0021] The water channel network of the present invention includes linear (straight or curved) open recesses or grooves formed on the surface, i.e., working surface, of an electrode substrate made of a metal such as titanium, niobium, or silicon that has excellent corrosion resistance and the ability to fix a deposited diamond layer via carbide. The substrate can be provided with distributed through-holes to expand the reaction area or to allow the water to be treated to flow from the opposite side (back surface) of the substrate. The distributed formation of through-holes in a substrate is itself well known, but by connecting them with water channels as described below, they can be used as a component of the water channel network of the present invention. The water channel network can be said to provide a flow path for guiding the movement of the water to be treated on the working surface of the electrode body, and the flow path can be configured in various ways by functionally connecting the water channels and through-holes, as described in detail below.

[0022] The shape of the electrode substrate depends on the design of the electrolytic cell. Circular or ring shape (Circular with a through hole in the center) Polygonal shapes, etc., distributionThe water channel network of the present invention can be used on a variety of substrates as long as they have a flat surface, with or without through holes, and the water channel network pattern is designed according to the geometric shape of the working surface, and is constructed by combining and arranging long and short water channels. Each water channel is formed on the working surface by laser processing or other existing techniques as a groove with a width of at least 0.1 mm and a depth of at least 0.05 mm. In other words, the groove must be designed to be wider and deeper than the anchor grooves used to prevent the diamond film deposited on the substrate from falling off, and to function as a water channel. For rectangular, square, or other quadrilateral substrates, particularly on working surfaces without through-holes, it is simple to form multiple parallel straight water channels between the upstream outer edge and the opposite downstream outer edge of the substrate. However, for such processing, linear groove cutting by machining is preferable in terms of accuracy and processing time.

[0023] The water channel network of the present invention is designed according to the surface configuration of the electrode substrate, including the geometric shape and presence or absence of through-holes, and is composed of water channels formed as long, short, straight, or curved linear surface recesses. The through-holes also form part of the water channel network. This water channel network has multiple inlets opening at the upstream inlet end and multiple outlets opening at the downstream outlet end, providing multiple paths (flow paths) for guiding the water to be treated from the inlets to the outlets.

[0024] Each flow path can be constructed as a single long channel with both an inlet and an outlet, but it is also effective to connect multiple shorter channels with connecting channels that are formed in the intersecting direction and open to each other to form a combined flow path. The former type of channel can be called a full channel, and the latter type of channel can be called a partial channel or connecting channel. In this way, the waterway network of the present invention provides multiple flow paths from the inlet end to the outlet end.

[0025] The configuration of the waterway network of the present invention can be designed, for example, as follows. For simple surfaces without through holes, quadrilaterals and Other than squares In a polygonal substrate, the channel network can consist exclusively of channels that run from the upstream end to the downstream end, whereas in a ring substrate, (Circular substrate with a through hole in the center)It is efficient to form these all-through channels as a group of parallel straight lines in the former case, and as a radial line in the latter case. Also, it is efficient to form the direction in which they intersect with these channels midway along their length, i.e., perpendicular in the former case, and 1-way in the former case. t Alternatively, it is also effective to form a plurality of concentric connecting water channels with different radii and connect them by opening them to all of the water channels.

[0026] In a substrate having a large number of distributed through-holes, when it is difficult to extend all of the water channels, the water channel network of the present invention can ensure a flow path from the upstream end to the downstream end of the substrate by connecting each through-hole and the through-hole with an upstream end and a downstream end with short water channels. If there is a surface area where a flow path can be formed that does not go through the through-holes, there is no problem in using a combined flow path that connects all of the water channels that do not go through the through-holes or partial water channels with connecting water channels.

[0027] The connecting water channel can be widely used as a component for connecting all the above-mentioned water channels, connecting the holes in a substrate with through-holes, or connecting the holes to the upstream or downstream end. The supply of water to be treated is ensured by connecting the through-holes, but it is also possible to design it to increase the amount of water passing through by prioritizing the averaging of the water flow and the reduction of water flow resistance.

[0028] In the present invention, in the case of a circular or annular substrate having a relatively large through-hole (main hole) in the center of the substrate, a typical example of a water channel network is to form radial all-through channels along the direction of the water flow when a water flow is applied from the periphery to the center or in the opposite direction. In this case, it is appropriate to connect adjacent all-through channels with connecting channels that are full or partial circles (arcs) of multiple concentric circles with different radii. The insertion of connecting channels reduces water flow resistance, thereby increasing the amount of water passing through, and also increases the area of ​​the three-phase interface, potentially increasing the amount of ozone generated. Laser or mechanical processing can be used to form all-through channels, as in the case of a quadrilateral substrate.

[0029] In the above, it is convenient to set the channel spacing at equal angles, but since the circumferential spacing increases on the outer periphery, it is preferable to make it as small as possible. However, as the angular spacing (pitch) becomes smaller, the density increases on the inner diameter side, while the spacing becomes too large on the outer periphery side, so it is also effective to form a multi-pitch radial channel configuration in which the main channel does not reach the entire outer periphery, but rather forms a channel with a smaller pitch up to the middle of the ring width or from there, and connects both channels with a connecting channel.

[0030] After the channel formation process, the electrode substrate is then subjected to a CVD process to deposit or coat the surface with boron-doped conductive diamond (BDD) particles or a film for use as an anode plate. If measures are taken to prevent the diamond from being altered by heat, laser groove cutting can also be performed on the BDD-coated anode plate as a post-processing step. Even in the case of a film, the BDD coating has many gaps, allowing the inflow of treated water from above the working surface. In the area where the BDD and SPE film are close to each other on the working surface, ozone is generated by an electrolytic reaction and dissolved in the water. It flows along the main and connecting channels toward the outlet.

[0031] In the present invention, by providing multiple water channels on the anode surface and taking in the water to be treated into the channels, the water in the channels is used in the electrolysis reaction, which increases the area of ​​the three-phase interface and reduces the electrical resistance. Furthermore, the formation of these water channels makes it possible to increase the current density (conduction of H+ ions), and when operating at the same voltage as conventional electrodes, it is possible to improve the water electrolysis rate.

[0032] Furthermore, the reduction in electrical resistance has enabled lower voltage operation when operating at the same current density (i.e., the same water electrolysis rate) as conventional electrodes. As a result, even in areas where the introduction of water electrolysis equipment has been hindered due to high tap water hardness and the electrodeposition of minerals during water electrolysis, the electrodeposition reaction of minerals on the cathode surface can be suppressed, and an extension of the equipment lifespan is expected.

[0033] 1, which shows an example of a water channel network configuration in an electrode assembly according to the present invention, the electrode assembly shown as an entirety 10 has a substrate 11 made of a square (rectangular) metal plate, across the surface of which a large number of linear grooves 12, each of which forms a full-length water channel, are formed in parallel, extending from one end to the other, to form a water channel network 13. These full-length water channels intersect with connecting water channels (connecting water channels) 14-18 every few lines along their length, allowing water to flow between them.

[0034] The working surface of the electrode substrate, particularly when it is circular, is provided with a hole (main hole) penetrating the entire thickness of the substrate at the center of symmetry or at another location, allowing water (the water to be treated) to pass from the opposite (back) side of the working surface of the substrate to the working surface, and multiple water channels opening on the inner peripheral edge are extended radially from the end of the substrate to the outer periphery. In this case, adjacent pairs of water channels may be connected by a water channel that reaches both of them.

[0035] Figure 2 Circular (annular) with a through hole in the center In the example of electrode body 20, a metal plate 21 of the same type as above has a circular through-hole 22 in the center, and multiple linear water channels 23 (24 in the figure) extend radially from this hole to the periphery. Connecting channels 24-26 extend in an annular shape, intersecting these channels midway along their length. This connection allows water to flow between the radial channels, forming a water channel network 27 as a whole.

[0036] A detailed example of the configuration of a water channel network in an electrode substrate with many through-holes is shown in Figure 3. In this figure, each through-hole 31 is connected to adjacent surrounding through-holes by connecting water channels 32 extending in six directions, and the water to be treated is guided to the downstream end through these connections. In this figure, the water channel network is composed only of through-holes and connecting water channels, but if there are blank areas on the surface without through-holes, it is also possible to install a main water channel (not shown) that runs from the upstream inlet end to the downstream outlet end.

[0037] This adds three-phase interface regions formed at the intersections between the SPE membrane and both banks of each water channel to the three-phase interface regions approximately 0.05 mm wide formed by the intersection of the outer edge of the through-hole and the SPE membrane, making it possible to increase the electrolysis current and improve the amount of ozone generated.

[0038] The water channel of the present invention is generally called a microchannel, and substances produced by water electrolysis (e.g., oxidizing agents such as ozone and hydrogen peroxide) diffuse rapidly within the water channel, enabling their reaction with other substances contained in the water to be promoted. For example, if wastewater containing harmful impurities is directly electrolyzed through an electrolysis device incorporating the electrodes of the present invention, the impurities in the wastewater can be efficiently oxidized and decomposed within the microchannel.

[0039] The electrode with water channels of the present invention is highly effective when used in processes and equipment that require the promotion of reactions between ozone or hydrogen peroxide generated by electrolysis and other substances contained in water. In other words, the electrode with water channels of the present invention is expected to be even more effective when incorporated into water electrolysis equipment intended for wastewater purification, making river water drinkable, etc. [Example]

[0040] The outer and inner diameters of the tube, which has many fine through-holes, are φ35 mm and φ11 mm (area: approximately 8.6 cm). 2 ) An electrode substrate having a water channel network formed according to the present invention was prepared using a 0.5 mm thick annular niobium plate, and for comparison, an electrode substrate of a conventional construction without a water channel network was prepared.

[0041] First, on the electrode substrate of the present invention, seven rows of through holes (small holes) with a diameter of 1.0 mm were formed at intervals of approximately 0.5 mm across the entire surface, with 28 rows of four holes radially arranged from the center hole (Figure 4). Next, 56 main water channels, each 0.1 to 0.2 mm in width and depth, were formed between each row of through holes, extending from the central hole to the outer periphery, and connecting channels were formed from each through hole to four adjacent through holes, connecting the adjacent through holes to the main water channels.On the other hand, the electrode substrate for comparison was used as is without providing the above-mentioned water channels.

[0042] A BDD film approximately 5 μm thick was deposited on the substrates of the present invention and the comparative example by the hot filament method. The area that mainly contributes to ozone generation is the area of ​​the three-phase interface where the BDD as the catalytic material on the anode side, the polymer electrolyte membrane (Nafion membrane), and water meet, with a width of approximately 0.05 mm. Therefore, the three-phase interface area per hole = 0.16 mm 2 (π × 1mm × 0.05mm), plus the sum of the three-phase interfacial areas on both sides of each channel, which is approximately 0.15 mm 2 This has increased the area of ​​the three-phase interface by approximately double compared to conventional products without grooves, thereby improving catalytic activity.

[0043] These electrodes were installed in the accelerated oxidation water production device with a built-in mixer described in Publication No. 2020-171238, and an ozone water generation test was conducted using tap water. This device is a home ozone water generation device with a circular water electrolysis device for generating ozone gas at the bottom of an acrylic container with an inner diameter of 50 mm and a length of 170 mm, and a mixer for dissolving ozone gas in water above. The current-voltage characteristics in electrolysis using the electrode of the present invention are shown in FIG. 5 in comparison with those using a conventional electrode.

[0044] In the conventional ozone water generator equipped with a boron-doped diamond electrode without a water channel, the current density was 0.2 A / cm 2 It was found that a voltage of about 7.2 V was sufficient for the electrode of the present invention, whereas a voltage of 9 V was required to pass a current of 1.72 A.

[0045] By lowering the operating voltage to approximately 7V, the amount of mineral deposits on the cathode can be reduced to as close to zero as possible, and the possibility of improving electrode life and electrolysis of hard water has been recognized. - The amount of ions mark This becomes noticeable from an applied voltage of around 8V. - It is known that ions in water can cause problems such as Ca, Mg, etc. to precipitate on the cathode surface in the form of hydroxides or carbonates. markWater electrolysis using applied voltage has led to a wide range of applications.

[0046] On the other hand, when water is electrolyzed at an applied voltage of 8 V, the current density is 0.15 A / cm with conventional electrodes. 2 (current value 1.25 A), but with the electrode of the present invention, the current density was 0.3 A / cm 2 (current value 2.5A). In other words, it became possible to generate twice the amount of ozone with an applied voltage of 8V using an anode plate of the same apparent area. From another perspective, the dissolved ozone concentration in ozonated water obtained by water electrolysis at 9 V, at which conventional electrodes cause significant problems with electrodeposit adhesion to the cathode surface, is 0.48 mg / L. However, by using the electrode of the present invention and lowering the applied voltage by 1 V to 8 V, it is possible to obtain an ozone concentration of 0.75 mg / L, which is about 1.5 times higher, while avoiding problems with electrodeposit adhesion, demonstrating a clear advantage. [Explanation of symbols]

[0047] 10 Electrode body 11 Circuit Board 12 Connecting canal (straight) 13 Waterway network 14~18 Connecting canals 20 Annular electrode body 21 Metal plate 22 through holes 23 (radial) waterways 24~26 Connecting canal (circular) 27 Waterway network 31 through hole 32 Connecting Canal

Claims

1. An electrode body for a zero-gap electrolysis device for ozone generation, the electrode body having a substrate made of a conductive material and a flat working surface coated with a boron-doped diamond (BDD) catalyst layer, The electrode body is a water channel that is provided on the working surface of the electrode body, is open, and is formed as a depression in the thickness direction of the substrate relative to the working surface, for guiding water; The electrode body is the boron-doped diamond catalyst coating the working surface of the electrode body; a solid polymer electrolyte (SPE) membrane covering the boron-doped diamond catalyst layer and closely covering the open surface of the water channel; By adopting such a configuration, at least at the bank edge of the water channel, the water, the boron-doped diamond catalyst layer, and the solid polymer electrolyte membrane come together to form a three-phase interface region, An electrode body in which a water channel network including a plurality of the water channels has respective openings, inlets and outlets, for the inflow or outflow of the water to be treated on the outer periphery and working surface of the substrate, and the water channels form a water flow path from the inlets to the outlets by being connected to other water channels individually or by the intersection of water channels with different directions.

2. 2. The electrode assembly of claim 1, wherein the water channel network includes a plurality of linear water channels extending parallel to the substrate in the same direction, at least one of the water channels having an inlet opening opening outward at an upstream end of the working surface, and at least one of the water channels having an outlet opening opening outward at a downstream end of the working surface.

3. 3. The electrode assembly according to claim 2, wherein the water channel network includes a plurality of linear first water channels extending parallel to the substrate in the same direction, and linear second water channels extending and intersecting the first water channels, and at least a pair of adjacent first water channels are connected to each other by intersecting second water channels.

4. 4. The electrode assembly according to claim 3, wherein the substrate is a quadrilateral or a polygon other than a quadrilateral, and the water channel network includes a plurality of linear water channels extending in parallel in the same direction.

5. 2. The electrode assembly according to claim 1, wherein the substrate is circular and has a through hole at its center that penetrates the thickness of the substrate, and the water channel network includes a plurality of linear water channels that extend radially from the periphery of the central through hole.

6. 2. The electrode assembly of claim 1, wherein the substrate is circular and has a through hole in the center that penetrates the thickness of the substrate, the water channel network includes a plurality of linear first water channels extending radially from the periphery of the central through hole, and second water channels extending on a circumference concentric with the outer periphery of the substrate, and at least one pair of adjacent first water channels intersects with the second water channel, and both water channels are connected by the second water channel.

7. 2. The electrode assembly according to claim 1, wherein the water channel network includes a plurality of through holes formed on the active surface and penetrating the entire thickness of the substrate, and a plurality of water channels extending between the through holes and connecting adjacent through holes to each other.

8. 2. The electrode assembly of claim 1, wherein the water channel network includes a plurality of through holes formed on the active surface and penetrating the entire thickness of the substrate, and a plurality of water channels extending between the through holes and connecting adjacent through holes to each other, one or more of the water channels opening outward at the upstream end of the substrate and one or more of the water channels opening outward at the downstream end, each providing an inlet and an outlet.

9. The electrode body according to claim 1 , wherein the substrate is made of Ti, Nb, or Si.

10. 2. The electrode assembly according to claim 1, wherein the width of the water channel is 0.1 mm or more.

11. 2. The electrode assembly according to claim 1, wherein the depth of the water channel is 0.05 mm or more.

12. (1) An electrode body in which a substrate of an electrode body made of a conductive material has a flat working surface coated with a boron-doped diamond (BDD) catalyst, the working surface has a water channel network consisting of a collection of water channels or linear grooves formed as recesses in the thickness direction of the substrate, and openings for the inflow and outflow of the water to be treated into the water channel network are provided on the outer periphery of the substrate and on the working surface, (2) The electrode body is used as an anode, and the working surface is closely attached to a solid polymer electrolyte (SPE) membrane. A cathode is placed on the back of the SPE membrane, and the working surface is placed horizontally in an electrolytic cell and immersed in water. (3) A flow of water to be treated is formed, and the water is supplied to the SPE by flowing the water from the inlet through the water channel into the gap between the anode working surface and the SPE membrane; (4) Applying an operating potential between the two electrodes capable of generating ozone to generate ozone at the three-phase interface along the water channel and to generate a water flow through the water channel; (5) A method for producing ozone water, characterized in that the produced ozone is transported outside the action surface by the water flow, dissolved in the surrounding water, and collected and recovered.

13. 13. The method for producing ozone water according to claim 12, wherein the operating potential is 8 V or less.

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