JPH06233983A - Three dimensional electrode-type electrolytic tank - Google Patents

Abstract

PURPOSE:To inhibit the deterioration of a carbonaceous three dimensional electrode to a minimum extent, and a the same time, make the electrode usable for oxygen generation electrolysis by forming a silicon carbide-coated layer on the positively polarizable surface of the carbonaceous there dimensional electrode of a three dimensional electrode-type electrolytic tank. CONSTITUTION:A silicon carbide-coated layer 7 is formed on the positively polarizable surface, that is, the surface where oxygen generates, of a carbonaceous three dimensional electrode 5 of a three dimensional electrode-type electrolytic tank 2. This coatd layer 7 prevents oxygen which generates due to electrolysis or during electrlytic treatment from coming into contact with the carbonaceous electrode 5. In addition, carbon dioxide is prevented from generating beyond a required generation level by inhibiting the desorption of carbon dioxide generated by chemical reaction between oxygen and the electrode 5. Consequently, it is possible to inhibit the deterioration of the carbonaceous three dimensional electrode to a minimum extent and utilize the electrode as an oxygen generation electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional electrode type electrolytic cell used for treating various kinds of water to be treated and electrolyzing various electrolytes, and more specifically to sterilizing water to be treated containing microorganisms such as water for fish farming. The present invention also relates to a three-dimensional electrode type electrolytic cell using a carbonaceous three-dimensional electrode suitable for electrolytic treatment or electrolysis of an electrolytic solution while improving performance or generating gas such as silver recovery from a photographic processing solution.

[0002]

2. Description of the Related Art In addition to natural fish that breed in the sea and rivers as various fish resources, recently, farmed fish in farms and the like have attracted attention, and many farmed fish have been supplied to the market. When breeding these fish in aquaculture farms, bacteria and molds, which are abundant in the water for fish farming, may inhibit the growth of the fish or kill them, but even if there are few bacteria, the fish are contaminated. It adheres to fish or fish and reduces its commercial value. In order to suppress these adverse effects, a fungicide such as a bactericide is added to the water for fish culture in a large amount, and further, an antibiotic is administered in order to suppress the damage of the fish due to the fungicide to the minimum source. In addition, a large amount of nutrients such as vitamins is administered to fish in order to increase resistance, and food is provided on the fish. Therefore, the fish that are bred have a small amount of food required for rearing with respect to the total intake, so that the growth rate, which is essential in aquaculture, is slowed down, and further growth of the antifungal agent is inhibited or the growth of human body is inhibited. Fish that are contaminated with a mildew-proofing agent will be supplied to the market. Further, dissolved oxygen of about 8 ppm exists in the water for fish farming as in ordinary water, and fish ingest this oxygen to grow. Administration of a large amount of chemicals reduces the dissolved amount of this oxygen, or reacts with dissolved oxygen to reduce the dissolved oxygen amount and inhibits growth. Of course, in addition to water for fish farms, there is water to be treated that requires electrolysis or electrolysis with gas generation.

[0003]

Problems to be Solved by the Invention The protection of fish by the above-mentioned antifungal agent is not only a problem of contamination of the fish itself, but also the amount of antifungal agent to be used is large because the amount of water for fish farming is huge. There is also a problem that the cost increases. Further, the cost of the nutritional supplement that accompanies the use of the fungicide also becomes enormous, and it is not directly connected to the growth of fish, but rather, the use of the fungicide which causes an adverse effect can be avoided at a low cost to the human body. The advantages are enormous because harmless fish can be grown and commercialized in a short period of time. Further, if the dissolved oxygen concentration of the fish culture water can be increased, the activity of the fish becomes active, and accordingly, the intake of food is increased and the growth of the fish is remarkably promoted. If the dissolved oxygen concentration can be increased at a low cost, it is possible to cultivate and supply to the market fish that are larger in size and have higher commercial value than ordinary cultured fish in a short period of time.

Further, in the case of antifungal treatment of treated water other than water for fish farms, the use of antifungal agents causes the same drawbacks, and the increase of dissolved oxygen amount often brings various advantages. A three-dimensional electrode having an enormous surface area is widely used as an electrolytic cell used for electrolytic treatment or electrolysis involving such gas generation. However, the material of the three-dimensional electrode is inexpensive and excellent in performance as an electrode substance. Carbonaceous material is used.
However, when the carbonaceous material comes into contact with oxygen gas, carbon on the surface thereof reacts with the oxygen gas and is eluted as carbon dioxide to be consumed.

[0005]

An object of the present invention is to provide a three-dimensional electrode type which uses a carbonaceous material, which is inexpensive and has excellent activity as an electrode material, but lacks resistance to oxygen gas, which is often generated by electrolysis, as its three-dimensional electrode. It is intended to provide an electrolytic cell.

[0006]

According to the present invention, in a three-dimensional electrode type electrolytic cell containing a carbonaceous three-dimensional electrode as an electrode, a coating layer of silicon carbide is formed on a surface of the carbonaceous three-dimensional electrode which is positively polarized. It is a three-dimensional electrode type electrolytic cell characterized by being formed. In the present invention, since the electrochemical reaction such as substantial redox reaction may not occur on the surface of the electrode, the device according to the present invention should be called an electrochemical treatment device. Called.

The present invention will be described in detail below. The present invention is
In view of the characteristics of a carbonaceous material that is inexpensive and has excellent activity as an electrode substance, but lacks resistance to oxygen gas often generated by electrolysis, the carbonaceous material is a slight carbonaceous material for electrolysis involving oxygen gas generation. A three-dimensional electrode type electrolytic cell having a three-dimensional electrode of the carbonaceous material, which can efficiently perform electrolysis or electrolytic treatment only with the consumption of materials.
This can be achieved by forming a coating layer of silicon carbide on the anodic polarization side of the carbonaceous three-dimensional electrode. The electrolytic cell according to the present invention is a three-dimensional electrode type electrolytic cell having a carbonaceous three-dimensional electrode, and is a bipolar electrode fixed bed type three-dimensional electrode type electrolytic cell, a single electrode fixed bed type three-dimensional electrode type electrolytic cell and It includes a bipolar electrode fluidized bed type three-dimensional electrode type electrolytic cell and the like. In normal electrolysis or electrolytic treatment, the more often the water to be treated or the electrolytic solution comes into contact with the three-dimensional electrode or the like, the higher the electrolysis efficiency or treatment efficiency. Therefore, using a three-dimensional electrode electrolytic cell such as a bipolar fixed bed type with a large surface area such as electrodes can improve the processing efficiency compared to the case of using other electrolytic cells, thereby achieving the same processing efficiency. This is advantageous in that the device size required for this can be made smaller than other electrolytic cells.

The carbonaceous three-dimensional electrode in the three-dimensional electrode electrolytic cell of the present invention is made of a porous material that is permeable to the water to be treated or the electrolytic solution, for example, granular, spherical, felt-like, woven cloth-like, porous block-like. , A plurality of carbonaceous materials such as solid carbon having a large number of through holes formed therein, such as solid carbon, graphite, carbon fiber or the like, or a material obtained by coating the carbonaceous material having the same shape with a noble metal It is preferably composed of a single dielectric. The three-dimensional electrode is placed in a direct current or alternating current electric field, and a direct current voltage or a low frequency alternating current voltage is applied between the positive and negative electrodes for power supply which are formed at the both ends and are made of a plate-shaped or expanded mesh-shaped or perforated plate-shaped porous plate. When applied, the three-dimensional electrode is polarized, and positive and negative charges are formed at one end and the other end of the three-dimensional electrode to polarize the three-dimensional electrode. In addition to this, separate from the power supply anode and cathode, a carbonaceous three-dimensional material that functions alone as an anode or as a cathode is installed so as not to be short-circuited alternately and electrically connected to form a multipolar fixed bed electrolysis. It can be a tank. When using a solid body having a large number of through holes as described above as a three-dimensional electrode, the aperture ratio is 10% or more and 95% or less, preferably 20% or more so as not to interfere with the movement of the water to be treated. 80% or less.

When the water to be treated is treated using a carbonaceous material such as activated carbon, graphite or carbon fiber as the carbonaceous three-dimensional electrode, the three-dimensional electrode is oxidized by oxygen gas generated by the anodic reaction. It becomes easy to dissolve as carbon dioxide. In order to prevent this, in the present invention, a coating layer of silicon carbide is formed on the surface of the three-dimensional electrode that undergoes positive polarization.
That is, in the fixed bed type three-dimensional electrode, the silicon carbide coating layer is formed on the surface facing the power feeding cathode terminal, and the silicon carbide coating layer is formed on both surfaces facing the both power feeding electrode terminals when an AC voltage is applied. Further, in the fluidized bed type three-dimensional electrode, the surface facing the power supply cathode terminal is not constant, so that it is preferable to form a coating layer on the front surface. The silicon carbide coating layer may be formed by the following method, for example. First, a commercially available silicon carbide fine powder is sieved to make the diameter uniform, and then the carbonaceous three-dimensional electrode is sprayed at a high temperature. Secondly, a source gas containing a silicon source and a carbon source is vaporized. A chemical vapor deposition method of decomposing to form a silicon carbide layer on the surface of the carbonaceous three-dimensional electrode;
The carbonaceous three-dimensional electrode is reacted with silicon oxide (for example, S
iO ₂ + C → SiO + CO, SiO + C → SiC + C
O) to coat the surface of the electrode with a silicon carbide layer.

The silicon carbide coating layer thus formed is presumed to have a large number of silicon carbide powders (or particles) adsorbed on the surface of the carbonaceous three-dimensional electrode as a single coating layer, and adjacent to each other. There is a space between the silicon carbide particles and the water to be treated or the electrolytic solution is brought into contact with the carbonaceous three-dimensional electrode through the space to be electrolyzed or electrolyzed. Due to the presence of the silicon carbide coating layer, desorption of carbon dioxide produced by the reaction of the carbonaceous three-dimensional electrode and oxygen gas generated by electrolysis is inhibited, and the production of more carbon dioxide is suppressed. It is considered that the elution of the carbonaceous three-dimensional electrode is effectively prevented. In order to further suppress the elution of the carbonaceous three-dimensional electrode, titanium or the like is added to the surface of the carbonaceous three-dimensional electrode on which the silicon carbide coating layer is formed, that is, the positively polarized side of the carbonaceous three-dimensional electrode. A platinum group metal oxide such as iridium oxide or ruthenium oxide is coated on a base material and a porous material which is usually used as an insoluble metal electrode is placed in contact with the base material so that oxygen generation mainly occurs on the porous material. do it.

In the electrolytic cell of the present invention, when the carbonaceous three-dimensional electrodes are brought close to each other or the three-dimensional electrodes and the feeding electrode terminal are intended to be lowered, an electrically insulating spacer is provided to prevent a short circuit. For example, it is preferable to insert a mesh spacer made of an organic polymer material. The three-dimensional electrode type electrolytic cell of the present invention can be used not only for electrolysis or electrolysis treatment involving gas generation but also for electrolysis treatment without gas generation. When used for electrolysis or electrolysis with gas generation, the generated oxygen gas and hydrogen gas are usually generated at a mixing ratio within the explosion limit, so an inert gas such as air is used to avoid the danger of explosion. It is preferable to dilute with. For example, the separation means for the electrolytic gas generated at the outlet of the electrolytic cell and the separated electrolytic gas are diluted with air so that the electrolytic gas concentration is 4%.
It is preferable to install a means for diluting so as to have a volume% or less, but if the capacity of the electrolytic cell is relatively small and the amount of generated gas is small, the gas separating means may not be installed.

The three-dimensional electrode type electrolytic cell according to the present invention can be used for various purposes, but can be preferably used for modification treatment such as sterilization of water to be treated containing microorganisms. For example, fish culture water has an appropriate temperature and is supplemented with nutrients, and is in an environment where molds, bacteria and the like easily propagate. In the conventional electrolysis or electrochemical treatment, since the mold and bacteria are not ionized, the number of cells that are killed by the redox reaction on the electrode surface is extremely limited and is not completely sterilized. It is presumed that the situation is such that the bacteria that have strong resistance to chemical treatment are propagated instead. When a DC voltage or a low frequency AC voltage is applied to the water to be treated from the electrolytic cell of the present invention, non-ionized molds and bacteria in the water to be treated also flow through the anode or cathode of the three-dimensional electrode type electrolytic cell or as described later. It is considered that the three-dimensional electrode having a three-dimensional structure having an extremely large surface area, such as a dielectric or particle, is sufficiently brought into contact with the surface and undergoes a redox reaction to destroy and kill the cell. Therefore, an equivalent bactericidal or antifungal effect can be produced without using a conventional bactericide or antifungal agent.

Further, when the water to be treated is hard water, it contains impurities such as calcium ions and magnesium ions. When the water to be treated is subjected to an electrolytic treatment, it is reduced on the cathode or the three-dimensional electrode of an electrolytic cell or a three-dimensional electrode type electrolytic cell and deposited as hydroxides on the cathode or the like to be removed from the water to be treated. It will not adversely affect the fish. Generally, in the electrolytic treatment operation of the fish culture water, in order to increase the amount of dissolved oxygen, which has a favorable effect on the growth of fish, the electrolytic treatment is performed while actively generating oxygen gas. The surface of the carbonaceous three-dimensional electrode is easily eluted, but the elution is suppressed as described above by the silicon carbide layer coated on the surface, and effective electrolysis or electrolytic treatment with oxygen generation is performed. Will be possible.

In the present invention, the value of the DC voltage or the low-frequency AC voltage applied between the positive and negative cathode terminals for power supply is not particularly limited, and may be any value that causes high current density electrolytic treatment in which gas generation occurs on the electrode surface. The frequency when using an AC voltage is preferably 10 Hz or less. When the treatment of the water to be treated or the electrolysis of the electrolytic solution is performed while the gas is generated by the electrolytic cell of the present invention, a part of the oxygen generated from the polarized three-dimensional electrode is subjected to the electrolytic treatment as it is. Dissolved in the water to be treated to raise the dissolved oxygen concentration to a value higher than the normal value, and the oxygen concentration consumed by the bacteria disappears due to the killing of the bacteria, so the oxygen concentration further increases and the fish The oxygen concentration can be set to be favorable for the growth of Anode potential is +0.2 to +1.5
V (vs.SHE) can be used for sterilization of water for fish farming and removal of impurities, but since substantial oxygen gas generation occurs at +1.0 V or higher, the anode potential is +1.0 V or higher, preferably +
1.2V or more. The preferred cathode potential is -0.5 V (v
s.SHE), which is a more noble range, and is capable of sterilizing and removing impurities such as fish culture water to be treated within this range. Oxygen gas is generated at an anode potential of +1.2 V or more and a small amount of ozone gas is generated as a by-product, and both gases have a favorable effect on the growth of fish.

If there is a relatively large void in the electrolytic cell of the present invention through which the water to be treated or the electrolytic solution to be electrolyzed flows, the water to be treated can flow without contacting the three-dimensional electrodes. Since the treatment of water to be treated or the efficiency of electrolysis decreases,
It is desirable that the three-dimensional electrodes are arranged so that the flow of the water to be treated or the like in the electrolytic bath does not short-pass. When the water to be treated is water for fish farms, the three-dimensional electrode electrolyzer having such a configuration is installed close to a farm or fishing pond,
In the case of recovering silver from a photographic processing solution, it can be used by circulating a part of fish-culture water in the farm or the like and then returning it to the farm after performing sterilization or the like in the electrolytic bath or the like. It is possible to install electrolytic silver gas while being installed close to the photographic processing tank and circulating the photographic processing solution. If the water to be treated or the electrolytic solution supplied to the electrolytic bath is a laminar flow, it may pass through the electrolytic bath without sufficiently contacting the surface of the three-dimensional electrode. 10 for water
It is more preferable that the turbulent flow having a Reynolds number of 0 or more, particularly 500 or more, is passed through the electrolytic cell or the like while being sufficiently moved in the lateral direction.

In addition, when the effect is not sufficiently obtained by passing the electrolytic cell only once, the treated water or electrolytic solution which has been treated may be passed through the electrolytic cell again. It may be sequentially supplied to the electrolytic cell to increase the overall processing efficiency. Further, in the electrolytic cell of the present invention, a leakage current is generated in the electrolytic cell, and the leakage current may cause electrocution of fish in the fish farm, or may flow from the electrolytic cell through the water to be treated or the electrolytic solution into another metal member, May cause electrochemical corrosion such as elution. Therefore, the positive and negative electrode terminals for feeding in the electrolytic cell do not face each other
Alternatively, a member having higher conductivity than the water to be treated or the like may be installed in the inlet / outlet pipe of the electrolytic cell so that one end thereof can be grounded to cut off the leakage current.

Next, preferred examples of the electrolytic cell which can be used in the present invention will be explained based on the attached drawings, but the electrolytic cell used in the method of the present invention is not limited to this electrolytic cell. FIG. 1 is a schematic vertical sectional view showing an example of a bipolar electrode fixed bed type electrolytic cell that can be used as the electrolytic cell of the present invention. A cylindrical electrolytic cell body 2 having upper and lower flanges 1 is provided with a mesh-shaped power feeding anode terminal 3 and power feeding cathode terminal 4 near the upper end and the lower end, respectively. The electrolytic cell body 2 is preferably formed of an electrically insulating material that can withstand long-term use or re-use, and in particular, synthetic resins such as polyepichlorohydrin, polyvinyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, and polychloroethylene. , Phenol-formaldehyde resin and the like can be preferably used. The power supply anode terminal 3 for applying a positive DC voltage is, for example, a carbon material (eg, activated carbon, charcoal, coke, coal, etc.), a graphite material (eg, carbon fiber, carbon cloth, graphite, etc.), a carbon composite material (eg, carbon). Metal powder mixed and sintered), activated carbon fiber non-woven fabric (eg KE-1000)
Felt, Toyobo Co., Ltd.), or platinum, platinum,
It is formed of a material supporting palladium or nickel, a dimensionally stable electrode (platinum group oxide-coated titanium material), a platinum-coated titanium material, a nickel material, a stainless material, an iron material, or the like. Further, the power supply cathode terminal 4 facing the power supply anode terminal 3 and applying a negative DC voltage is, for example, platinum, stainless steel, titanium, nickel, hastelloy, graphite,
It is formed of a carbon material, mild steel, a metal material coated with a platinum group metal, or the like.

A plurality of, in the illustrated example, three fixed beds 5 clogged three-dimensional electrodes are stacked between the power feeding electrode terminals 3 and 4, and between the fixed beds 5 and between the fixed beds 5 and the above. Four porous diaphragms or spacers 6 are sandwiched between the power feeding electrode terminals 3 and 4. The surface of each fixed bed 5 facing the cathode terminal 4 for power supply is coated with a silicon carbide coating layer 7, and the fixed bed 5 is in close contact with the inner wall of the electrolytic cell body 2 and does not pass through the inside of the fixed bed 5 and is fixed. The leakage flow of the water to be treated or the like flowing between the floor 5 and the side wall of the electrolytic cell body 2 is arranged as small as possible. When a diaphragm is used, a woven cloth, a biscuit plate, a particle-sintered plastic, a porous plate, an ion exchange membrane, etc. are used as the diaphragm, and a woven cloth, a porous plate, a net made of an electrically insulating material is used as a spacer. , Rod-shaped materials are used. Electrolytic cell 2 having such a structure
When water is supplied while supplying water to be treated such as fish farming water or an electrolytic solution from below as shown by the arrow in FIG. 1, each fixed bed 5 is polarized so that its lower surface is positive and its upper surface is negative as shown. Fixed floor 5
An electric potential is generated between the inside and the fixed bed 5, and the water to be treated flowing in the electrolytic cell comes into contact with the fixed bed 5 which is positively or negatively polarized by this potential to generate oxygen gas, and the water to be treated is also generated. A reforming process is performed. The generated oxygen gas is dissolved in the water to be treated and is taken out from above the electrolyzer 2 as water to be treated having a higher concentration of dissolved oxygen gas than the water to be treated before being supplied to the electrolyzer 2. The presence of the silicon carbide coating layer 7 minimizes the elution of the fixed bed 5 due to oxygen gas, without replacing the fixed bed 5, that is, without disassembling and assembling the electrolytic cell, which is a complicated operation. It becomes possible to treat the water to be treated and electrolyze the electrolytic solution for a long period of time.

FIG. 2 shows another example of the bipolar electrode fixed bed type electrolytic cell of the present invention, which is the side of the fixed bed 5 of the electrolytic cell shown in FIG. A mesh-shaped insoluble metal material 8 is installed in a close contact state on the side of positive polarization. Since other members are the same as those in FIG. 1, the same reference numerals are given and description thereof is omitted. The fixed bed 5 to which the DC voltage is applied is most polarized at both ends thereof, and when the gas is generated, the gas is most violently generated at the both ends. Therefore, dissolution occurs most rapidly at the end portion of the fixed bed 5 which is most strongly anodic polarized, that is, where oxygen gas is most intensely generated, toward the feeding cathode 4. As shown in the figure, when the insoluble metal material 8 is installed in this portion, most of the oxygen gas is removed from the insoluble metal material 8 because the overvoltage of the insoluble metal material 8 is lower than the overvoltage of the carbonaceous material forming the fixed bed 5. Since the fixed bed 5 is generated and almost does not come into contact with oxygen gas, the elution of the fixed bed 5 is more effectively suppressed than in the case of FIG.
Further, the water to be treated and the like supplied to the electrolytic cell 2 is treated and reformed in the same manner as in FIG.

[0020]

EXAMPLES Examples of electrolytic treatment of water to be treated using the electrolytic cell of the present invention will be described below, but the examples do not limit the present invention. Example Made of transparent hard polyvinyl chloride resin, height 100 mm, inner diameter
The electrolytic cell shown in FIG. 1 having a cylindrical shape with a flange of 50 mm was installed together with a filter and a pump in a fish culture water circulation system of an aquarium for breeding goldfish. In the electrolytic cell, a silicon carbide coating layer having a thickness of 20 μm was formed on the side of a cathode terminal for power supply, which will be described later, and was made of carbon fiber and had a diameter of 50 mm and a thickness of 10 mm.
5 fixed beds, each of which is about 8.5 g in mm
It is sandwiched by six polyethylene resin diaphragms with a diameter of 50 mm and a thickness of 1.2 mm with an aperture ratio of 80%, and the diaphragms at the upper and lower ends are made of titanium with a platinum diameter of 48 m.
The mesh-shaped power feeding anode terminal and the power feeding cathode terminal having a thickness of 1.0 mm were placed in contact with each other. The silicon carbide coating layer was prepared by inserting a porous graphite electrode (G-505 manufactured by Toyo Carbon Co., Ltd.) into a chemical vapor deposition apparatus.
15% of methyltrichlorosilane in the state heated at 00 ℃,
A gas mixture of 85% hydrogen was circulated to form a 30 μm silicon carbide coating layer. The aquaculture water in the aquarium was fed to the electrolytic bath at a rate of 0.5 l / min, and the anode and cathode voltages shown in Table 1 were applied between the feeding electrode terminals to treat the aquaculture water. The number of bacteria and the dissolved oxygen concentration in the fish culture water before and after passing through the electrolytic cell and the average weight of each fixed bed after 72-hour electrolysis are summarized in the upper column of Table 1. The initial number of bacteria in the fish culture water before the start of electrolytic treatment was 384 colonies / ml.

Comparative Example Electrolytic treatment of fish culture water was carried out under the same conditions as in Example except that a silicon carbide coating layer was not formed on the fixed bed, and the number of bacteria and the dissolved oxygen concentration in the fish culture water before and after passing through the electrolytic cell and The average weight of each fixed bed after 72 hours of electrolysis is summarized in the lower column of Table 1. The initial number of bacteria in the fish culture water before the start of electrolytic treatment was 367 colonies / ml. It can be seen from Table 1 that by forming the silicon carbide coating layer, the sterilization efficiency and the amount of dissolved oxygen are not so affected, but the weight reduction of the fixed bed can be effectively suppressed.

[0022]

[Table 1]

[0023]

The electrolytic cell of the present invention is a three-dimensional electrode type electrolytic cell in which a coating layer of silicon carbide is formed on the positively polarized surface of the carbonaceous three-dimensional electrode of the three-dimensional electrode type electrolytic cell. 1). This silicon carbide coating layer suppresses the desorption of carbon dioxide generated by the reaction between the oxygen gas and the carbonaceous three-dimensional electrode that may occur during electrolysis or electrolytic treatment, and prevents further generation of carbon dioxide. You can do it. Therefore, the electrolytic cell of the present invention is suitable, for example, for treating fish-cultivating water in which it is desirable to carry out the reforming treatment while actively generating oxygen gas (claim 2). Furthermore, if an insoluble metal material is placed in close contact with the positive polarization side of the three-dimensional electrode (Claim 3), an oxygen generating reaction, which is an anodic reaction, occurs on the insoluble metal material and hardly occurs on the three-dimensional electrode. The chance of contact between the three-dimensional electrode and oxygen gas is greatly reduced, and the consumption of the three-dimensional electrode can be suppressed.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of a bipolar electrode fixed bed type electrolytic cell that can be used as the electrolytic cell of the present invention.

FIG. 2 is a vertical cross-sectional view showing an example of another bipolar electrode fixed-bed electrolytic cell

[Explanation of symbols]

1 ・ ・ Flange 2 ・ ・ Electrolyzer body 3 ・ ・ ・ Anode terminal for power supply 4 ・ ・ ・ Cathode terminal for power supply 5 ・ ・
・ Fixed bed 6 ・ ・ ・ Spacer 7 ・ ・ ・ Silicon carbide coating tank 8 ・ ・ ・ Insoluble metal material

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[Procedure amendment]

[Submission date] August 2, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

Front Page Continuation (72) Inventor Yoshito Sasaki 2-10-1 Nihonbashi, Chuo-ku, Tokyo Toyo Carbon Co., Ltd.

Claims (2)

[Claims] 1. A three-dimensional electrode type electrolytic cell containing a carbonaceous three-dimensional electrode as an electrode, wherein a coating layer of silicon carbide is formed on a surface of the carbonaceous three-dimensional electrode which is positively polarized. Electrode type electrolytic cell. 2. The electrolytic cell according to claim 1, which is for electrolytic treatment of fish culture water.