JP5408653B2 - Ozone generation method and ozone generation apparatus - Google Patents

Description

  In the present invention, an anode and a cathode are adhered to both side surfaces of a solid polymer electrolyte membrane, a perfluorosulfonic acid cation exchange membrane is used as a solid polymer electrolyte membrane, and an electrode having conductive diamond on the surface is used as an anode In addition, the present invention relates to an ozone generation method and an ozone generation apparatus that electrolyze water to generate ozone from an anode and hydrogen from a cathode.

  Ozone is known as a substance having an extremely strong oxidizing power in nature. In recent years, ozone has been used in various industrial fields by utilizing the strong oxidizing power. For example, the sterilization / decolorization method using ozone is used in water and sewage facilities. Ozone self-decomposes over time and becomes harmless oxygen, so there is no worry of secondary contamination due to residual chemicals or reaction products compared to conventional chemical sterilization / decolorization methods, and post-treatment is easy. Has been evaluated in addition to its strong disinfection and decolorization ability.

  As a method for generating ozone, an ultraviolet lamp method, a silent discharge method, and an electrolysis method are known. The ultraviolet lamp method is a method that excites oxygen by ultraviolet rays to generate ozone, and it can generate ozone with relatively simple equipment, but the amount generated is small, and it is widely used for deodorizing indoors and cars. Has been. The silent discharge method is the most widespread general ozone generation method, and uses a large generator of several tens of kg / h for simple purposes such as indoor deodorization using a small amount of ozone generator. It is used for various purposes up to large-scale water treatment. The silent discharge method is a method in which oxygen gas or oxygen in the air is used as a raw material, and oxygen is excited by a discharge to react with ozone.

  The electrolysis method is a method of obtaining ozone in the anode generation gas by electrolyzing water. Ozone is generated by electrolyzing an aqueous solution such as an aqueous sulfuric acid solution, but when ultrapure water electrolysis is performed using a solid polymer electrolyte known as a perfluorosulfonic acid cation exchange membrane as an electrolyte, the concentration and purity are high. It has a characteristic that it can produce ozone. In addition, since ultrapure water is used as a raw material and the impurities in the generated gas are extremely small, ultrapure water electrolysis ozone water production equipment is widely used in the precision cleaning field for cleaning semiconductor wafers, LCD substrates, etc. .

Conventionally, the anode of an ozone generation method by electrolysis has excellent ozone gas generation current efficiency, and therefore, lead dioxide (PbO ₂ ) supported by a method such as electrolytic plating on a conductive porous metal such as titanium has been used. It has been. When ultrapure water electrolysis is performed at room temperature using a perfluorosulfonic acid ion exchange membrane as a solid polymer electrolyte and lead dioxide as an anode, the ozone generation current efficiency usually shows 10-15%, and at a high current density Reaches 20%. Although the perfluorosulfonic acid ion exchange membrane is consumed over time, the consumption is small and stable ozone generation and safety can be maintained even after continuous electrolysis for 2 years or more.

As described above, the lead dioxide anode has high ozone generation current efficiency and excellent stability over time under high current density and continuous electrolysis, but this lead dioxide anode is easily reduced and deteriorated in a reducing environment. Has characteristics. For example, when the electrolysis is stopped, the lead dioxide on the electrode surface is easily converted to lead hydroxide (Pb) by reaction with a reducing substance such as hydrogen remaining in the electrolysis cell or by electroreduction reaction by negative polarization of the lead dioxide anode. (OH) ₂ ), lead oxide (PbO), and lead ions (Pb ²⁺ ). Since neither of these has an ozone generating ability or electronic conductivity, a phenomenon occurs in which the ozone generating ability is reduced during re-operation after the electrolysis is stopped.

  Therefore, in an electrolytic ozone generator using a lead dioxide electrode, in order to avoid performance degradation at the time of stopping, when the apparatus is stopped, a protective current that is 1/10 to 1/1000 of the normal electrolytic current is applied to the electrolytic cell. It has a supply mechanism. This mechanism is composed of a direct current power source for protection current, a storage battery, and a control system, and constantly monitors the status of the apparatus so that an instantaneous non-energized state does not occur in the electrolysis cell. This mechanism protects the lead dioxide anode without being exposed to the reducing environment even when electrolysis is stopped. However, the existence of this mechanism complicates the operating mechanism and configuration of the electrolytic ozone generator and increases the price of the apparatus. Yes.

  Moreover, the lead dioxide anode contains a lot of lead, and in recent years, due to the toxicity and legal requirements of lead, for example, the ROHS guidelines, the use of lead tends to be reduced in all industrial products (Non-Patent Document 1). reference).

  On the other hand, by conducting water electrolysis using a conductive diamond imparted with conductivity by adding a dopant such as boron in the crystal structure as an anode, the ozone generation current efficiency is about 40% much higher than that of the lead dioxide anode. I know I can get it. In addition, since the conductive diamond anode is excellent in chemical and electrochemical stability, it does not change in properties and electrolytic characteristics even in a reducing environment in which lead dioxide is altered or deteriorated by reduction. Therefore, the protective current mechanism which is essential in the electrolytic ozone generator using the lead dioxide anode is not necessary, and the apparatus is simplified. Of course, carbon and boron constituting the conductive diamond are not subject to the ROHS guidelines.

  However, since the conductive diamond electrode has a very strong oxidizing ability, water electrolysis can be performed while contacting the conductive diamond electrode and the perfluorosulfonic acid ion exchange membrane in the same manner as the conventional electrolytic ozone generation cell. When it did, it became clear that the consumption speed | rate of a perfluorosulfonic-acid ion exchange membrane was 100 times or more large compared with the case of a lead dioxide electrode. The rapid thinning of the membrane by electrolysis causes a rapid increase in the amount of hydrogen gas generated in the cathode chamber to the anode chamber, and the hydrogen concentration in the anode gas exceeds the lower limit of hydrogen explosion even in short-time electrolysis. An electrolysis cell having a very short period during which stable electrolysis can be performed is obtained. Therefore, although the conductive diamond electrode has an excellent ozone generation capability, it has been difficult to commercially use it as an electrolytic cell in an ozone generator or the like.

  Conventionally, an anode and a cathode are adhered to both sides of a solid polymer electrolyte membrane, a perfluorosulfonic acid cation exchange membrane is used as a solid polymer electrolyte membrane, a conductive diamond electrode is used as an anode, and water is electrolyzed. In the ozone generation method in which ozone is generated from the anode and hydrogen is generated from the cathode, as a method for suppressing the consumption of the solid polymer electrolyte membrane, the current efficiency between the anode and the cathode is expressed as current efficiency related to ozone generation. An ozone generation method and an ozone generation apparatus that control the current value to a maximum value or less have been proposed (see, for example, Patent Document 1 and Patent Document 2).

Japanese Patent No. 4220978 JP 2009-7655 A

Restrictions on the use of certain hazardous materials in electrical and electronic equipment: EG Guidelines 2002/95 / EG on January 27, 2003

  However, the conventional method described above is not sufficient in suppressing the consumption of the solid polymer electrolyte membrane.

  The present invention eliminates the disadvantages of the conventional methods described above, adheres the anode and cathode to both sides of the solid polymer electrolyte membrane, uses a perfluorosulfonic acid cation exchange membrane as the solid polymer electrolyte membrane, and conducts as the anode. In the ozone generation method that uses water-soluble diamond electrodes to electrolyze water to generate ozone from the anode and hydrogen from the cathode, the consumption of the perfluorosulfonic acid cation exchange membrane is suppressed, and stable, long-term, high current An object of the present invention is to provide an ozone generation method and an ozone generation apparatus capable of efficiently generating ozone.

  It is considered that the oxidation ability of conductive diamond is caused by radicals such as hydroxy radicals generated in accordance with the electrolytic reaction on the electrode surface. Hydroxyl radicals are known as radicals having higher oxidizing power than ozone, and a reducing substance called a radical scavenger is generally used for the disappearance. Therefore, electrolysis is performed, radicals are eliminated by appropriately supplying radical scavengers to the outermost surface of the anode where the radicals such as hydroxy radicals are generated, and the consumption rate of the film is suppressed. It can be imagined that it is effective in an electrolytic ozone generator using diamond. However, ozone generated at the anode and highly useful in the industrial field has high oxidizing power like radicals, and reacts with many chemical substances to be quickly reduced to oxygen.

  Therefore, the radical scavenger used for the purpose of suppressing the consumption of the perfluorosulfonic acid cation exchange membrane in this electrolysis method has the ability to react with radicals and lose its activity, and at the same time, against ozone and ozone precursors. Are required to be inert.

  For this reason, in the present invention, which substance is selected as the radical scavenger and how the selected substance is supplied to the reaction field is most effective in suppressing the consumption of the perfluorosulfonic acid cation exchange membrane. The present invention has been obtained by examining whether it is appropriate.

In order to solve the above problems, the present invention has an anode and a cathode in close contact with both sides of a solid polymer electrolyte membrane, uses a perfluorosulfonic acid cation exchange membrane as a solid polymer electrolyte membrane, and has a conductive property as an anode. By using an electrode having diamond on the surface, pure water is supplied to the anode chamber, and direct current is supplied between the positive and negative electrodes, thereby electrolyzing the water, generating ozone from the anode chamber, and generating hydrogen from the cathode chamber. in the ozone generating process of generating, in the anode chamber, lies in the configuration of an ozone generating method is characterized in that feeding at least one kind selected from water Moto及 beauty organics.

  The second problem-solving means according to the present invention uses a hydrogen gas generated in the cathode chamber or a catholyte in which the hydrogen gas is dissolved as a supply source of hydrogen to be supplied to the anode chamber. The ozone generation method is characterized in that it is supplied to the anode chamber from the outside of the anode chamber.

  According to a third means for solving the problem of the present invention, at least one selected from carbon dioxide and organic matter is supplied to the cathode chamber, and at least one selected from carbon dioxide and organic matter is supplied from the cathode chamber. The ozone generation method is configured so as to be permeated through a perfluorosulfonic acid cation exchange membrane and supplied to the anode chamber.

According to a fourth aspect of the present invention, there is provided an ozone generation method using alcohol as the organic substance.
It is to have done.

The fifth problem-solving means according to the present invention is such that an anode and a cathode are adhered to both side surfaces of a solid polymer electrolyte membrane, a perfluorosulfonic acid cation exchange membrane is used as the solid polymer electrolyte membrane, and the conductive material is used as the anode. Using an electrode having a conductive diamond surface, pure water is supplied to the anode chamber, and direct current is supplied between the positive and negative electrodes to electrolyze the water and generate ozone from the anode chamber. keep ozone generator used in the ozone generating method for generating hydrogen, it lies in the structure of the ozone generator to supply at least one selected the anode chamber from the water Moto及 beauty organics.

  The sixth problem-solving means according to the present invention uses hydrogen gas generated in the cathode chamber or a catholyte in which the hydrogen gas is dissolved as a supply source of hydrogen to be supplied to the anode chamber. The ozone generator is configured to supply the anode chamber from the outside of the anode chamber.

  According to a seventh means for solving the problem of the present invention, at least one selected from carbon dioxide and organic matter is supplied to the cathode chamber, and at least one selected from carbon dioxide and organic matter is supplied from the cathode chamber. The ozone generator is configured to transmit the perfluorosulfonic acid cation exchange membrane and supply it to the anode chamber.

  The eighth problem-solving means according to the present invention resides in that an ozone generator is constructed using alcohol as the organic substance.

  According to the ozone generation method and the ozone generation apparatus of the present invention, the anode and the cathode are brought into close contact with both sides of the solid polymer electrolyte membrane, a perfluorosulfonic acid cation exchange membrane is used as the solid polymer electrolyte membrane, and the anode is used as the anode. In an ozone generation method that uses an electrode with conductive diamond on the surface and electrolyzes water to generate ozone from the anode and hydrogen from the cathode, the consumption of the perfluorosulfonic acid cation exchange membrane is suppressed and stable. It can generate ozone for a long time.

The schematic diagram which shows the structure of one example of the electrolysis cell for implementing the ozone production | generation method and ozone production | generation apparatus by this invention. The schematic diagram which shows the structure of the other example of the electrolysis cell for implementing the ozone production | generation method and ozone production | generation apparatus by this invention. The surface view which shows the structure of one example of the anode which has the conductive diamond used for the ozone production | generation method and ozone production | generation apparatus by this invention on the surface. Sectional drawing which shows the structure of one example of the anode which has the conductive diamond used for the ozone production | generation method and ozone production | generation apparatus by this invention on the surface. The block diagram which shows one Example of the ozone production | generation method by this invention. The block diagram which shows the other Example of the ozone production | generation method by this invention. The block diagram which shows the further another Example of the ozone production | generation method by this invention. The block diagram which shows the further another Example of the ozone production | generation method by this invention.

  Hereinafter, an ozone generation method and an ozone generation apparatus according to the present invention will be described in detail with reference to the drawings.

  FIG. 1-1 is a schematic diagram showing a configuration of an example of an electrolytic cell for carrying out an ozone generation method and an ozone generation apparatus according to the present invention. 1 is an anode chamber discharge port, 2 is a cathode chamber discharge port, 3 is an anode chamber, 4 is a cathode chamber, 5 is an anode feeding terminal, 6 is a cathode feeding terminal, 7 is an anode chamber feeding port, 8 is a cathode chamber supply port, 9 is a polymer electrolyte membrane diaphragm made of a perfluorosulphonic acid cation exchange membrane, 10 is a conductive diamond film, 11 is a p-type silicon substrate with irregularities, and 12 is a through-hole. Mouth, 13 is a cathode sheet, 14 is a cathode current collector, 15 is a sealing material, 16 is a fastening bolt, 17 is a nut, and 18 is a press plate.

  The anode has a conductive diamond film 10 on the surface of the p-type silicon substrate 11 with unevenness, the through-hole 12 is perforated, the cathode is made of a cathode sheet 13, and the anode and the cathode are perfluorosulfonic acid. A so-called zero-gap cell was constructed by adhering to both surfaces of the polymer electrolyte membrane diaphragm 9 made of a cation exchange membrane. The anode and cathode are housed in an anode chamber 3 and a cathode chamber 4, respectively. The anode chamber 3 and the cathode chamber 4 have an anode chamber discharge port 1, a cathode chamber discharge port 2, an anode chamber supply port 7 and a cathode chamber supply port 8, respectively. doing.

  From the electrical contact between the constituent materials and the anode having the conductive diamond film 10 on the surface of the p-type silicon substrate 11 with unevenness, the cathode made of the cathode sheet 13, the cathode current collector 14, and the perfluorosulfonic acid cation exchange membrane The solid polymer electrolysis chamber diaphragm 9 was joined by using a tightening bolt 16, a nut 17, and a press plate 18 by torque. The torque to the bolt and nut was 3 N · m.

  When pure water is supplied into the anode chamber 3 from the anode chamber supply port 7, the pure water passes through the through-hole 12 and the like, and the solid polymer electrolysis chamber comprising the conductive diamond membrane 10 and the perfluorosulfonic acid cation exchange membrane. Supplyed to the contact surface of the diaphragm 9, an electrolytic reaction occurs, ozone gas, oxygen gas, and hydrogen ions are generated in the anode chamber 3, and the ozone gas and oxygen gas are discharged from the anode chamber outlet 1 to the outside of the electrolytic cell, Hydrogen ions permeate the solid polymer electrolysis chamber diaphragm 9 to reach the surface of the cathode sheet 13, combine with electrons, become hydrogen gas, and are discharged from the cathode chamber outlet 2 to the outside of the electrolysis cell.

  In the present invention, at least one selected from hydrogen, carbon dioxide, and organic matter is supplied into the anode chamber 3 from the outside of the anode chamber 3 together with pure water from the anode chamber supply port 7.

  In the present invention, a hydrogen gas generated in the cathode chamber 4 or a catholyte in which the hydrogen gas is dissolved is used as a hydrogen supply source to be supplied to the anode chamber 3, and the catholyte is supplied to the outside of the anode chamber 3. Further, it can be supplied to the anode chamber 3 together with pure water from the anode chamber supply port 7.

In the present invention, alcohol can be used as the organic substance. As the alcohol, isopropyl alcohol (IPA), methanol, ethanol and the like are preferable.

  Further, in the present invention, as the substance supplied to the anode chamber 3, hydrazine and other reducing agents can be used in addition to hydrogen, carbon dioxide and organic substances.

  FIG. 1-2 is a schematic diagram showing the configuration of another example of an electrolysis cell for carrying out the ozone generation method and the ozone generation apparatus according to the present invention. An example using a sulfonic acid cation exchange membrane is shown.

FIGS. 2-1 and 2-2 are diagrams showing a configuration of an example of an anode having conductive diamond on the surface used for an ozone generation method and an ozone generation apparatus according to the present invention, and a 5 cm square p-type silicon substrate ( A large number of irregularities with a pitch of 0.5 mm were formed on the surface of the surface of 3 mmt) 11 by dicing, and then drilled from the back surface to obtain a plurality of through holes 12. In order to texture the silicon surface, it is immersed in a hydrofluoric acid solution prepared by mixing 35% hydrofluoric acid and 70% nitric acid at 1: 1 at room temperature for 5 minutes, and further 10% potassium hydroxide aqueous solution at 60 ° C. For 5 minutes. Reference numeral 25 denotes a convex portion, and 26 denotes a concave portion.
After the silicon plate was washed with water and dried, as a pretreatment, diamond powder was placed in isopropyl alcohol, a substrate was placed, and ultrasonic waves were applied to perform seeding treatment. As a film forming method, a microwave plasma CVD method at 2.45 GHz was used. H ₂ , CH ₄ , and B ₂ H ₆ were used as gases, and the flow rates were 800 sccm, 20 sccm, and 0.2 sccm, respectively, and the gas pressure was 3.2 kPa. A conductive diamond film 10 containing boron as a dopant was formed by microwave plasma CVD. In addition, the total area of the convex part top part used as an actual electrolysis area is 6.25 cm < ² >.

  The anode having the conductive diamond film 10 on its surface is manufactured by supporting diamond, which is a reduced precipitate of an organic compound serving as a carbon source, on an electrode substrate. The material and shape of the electrode substrate are not particularly limited as long as the material is conductive. The electrode substrate is plate-like, mesh-like, or porous, for example, a vibrant fiber sintered body made of conductive silicon, silicon carbide, titanium, niobium, molybdenum or the like. It is particularly preferable to use conductive silicon or silicon carbide having a thermal expansion coefficient that can be used. In order to improve the adhesion between the conductive diamond and the substrate, and to increase the surface area of the conductive diamond film and reduce the current density per unit area, it is desirable that the substrate surface has a certain degree of roughness.

  When conductive diamond is used in the form of a film, it is desirable that the film thickness be 10 μm to 50 μm in order to reduce durability and occurrence of pinholes. Although a self-supporting film having a thickness of 100 μm or more can be used from the viewpoint of durability, it is not preferable because the cell voltage becomes high and the control of the electrolyte temperature becomes complicated.

The method for supporting the conductive diamond on the substrate is not particularly limited, and any conventional method can be used. Typical conductive diamond production methods include a hot filament CVD (chemical vapor deposition) method, a microwave plasma CVD method, a plasma arc jet method, and a physical vapor deposition (PVD) method. The use of a microwave plasma CVD method is desirable because it is easy to obtain a uniform film.
In addition, a diamond electrode in which a synthetic diamond powder produced at an ultrahigh pressure is supported on a substrate by using a binder such as a resin can also be used.

  The microwave plasma CVD method uses a mixed gas obtained by diluting a carbon source such as methane and a dopant source such as borane with hydrogen as a conductive material such as conductive silicon, alumina, or silicon carbide connected to a microwave transmitter through a waveguide. This is a method in which a conductive diamond film is introduced into a reaction chamber where a substrate is installed, plasma is generated in the reaction chamber, and conductive diamond is grown on the substrate. In the plasma by microwaves, ions hardly vibrate, and a pseudo high temperature is achieved in a state where only electrons are vibrated, and the chemical reaction is promoted. The plasma output is 1 to 5 kW, and the larger the output, the more active species can be generated, and the growth rate of diamond increases. The advantage of using plasma is that diamond can be deposited at high speed using a substrate with a large surface area.

  In order to impart conductivity to diamond, a small amount of elements having different valences are added. The content of boron or phosphorus is preferably 1 to 100,000 ppm, more preferably 100 to 10,000 ppm. As a raw material for this additive element, boron oxide, diphosphorus pentoxide, or the like having a low toxicity can be used. The conductive diamond supported on the substrate thus manufactured is a flat plate, stamped plate, wire mesh, powder sintered body made of a conductive material such as titanium, niobium, tantalum, silicon, carbon, nickel, tungsten carbide. In addition, it can be connected to a power feeding body having a form such as a metal fiber body or a metal fiber sintered body.

  As a perfluorosulfonic acid cation exchange membrane used for the polymer electrolyte membrane 9, a commercially available perfluorosulfonic acid cation exchange membrane (trade name: Nafion 117, manufactured by DuPont, catalog thickness 175 μm) is used. Then, it was immersed in boiling pure water for 30 minutes and swelled with water.

The cathode sheet 13 was manufactured as follows. PTFE dispersion (Mitsui Dupont Fluorochemical Co., Ltd. 31-J) and a dispersion of platinum-supported carbon catalyst dispersed in water were mixed, dried, kneaded with solvent naphtha added thereto, Through the drying step and the firing step, the cathode sheet 13 was obtained with PTFE 40%, platinum-supported carbon catalyst 60% in film thickness, and porosity of 55%.
Moreover, a 2.5 mm thick stainless steel fiber sintered body (Tokyo Seizuna Co., Ltd.) was used as the cathode current collector.

  Next, examples and comparative examples of the present invention will be described. However, the present invention is not limited to these examples.

<Example 1>
As shown in FIG. 3A, the electrolytic cell 24 is connected to an ozone side gas / liquid separator 19, a hydrogen side gas / liquid separator 20, and a DC power source 21, and the anode chamber 3 is cooled with pure water as an electrolyte. The water was electrolyzed while supplying. The electrolytic current was 6.25A. However, two solid polymer electrolyte membranes 9 made of perfluorosulfonic acid cation exchange membranes used in the electrolytic cell 24 were used in an overlapping manner as shown in FIG.
Furthermore, hydrogen water was mixed and supplied to the water circulatingly supplied to the anode chamber 3 by 0.5 ml / min (approximately 2 vol% with respect to the amount of generated anode gas), and pure water electrolysis was performed. The ozone generation current efficiency at 22 was 40%, the hydrogen gas concentration contained in the anode gas was 0.07 vol%, and the cell voltage was 12V.

  When 6.25 A was continuously supplied to the electrolysis cell 24 and continuous electrolysis was performed for 29 hours, the ozone generation current efficiency during this period was not significantly changed as 40 to 42%. After 29 hours, the electrolytic cell 24 was disassembled, and the consumption thickness of the film where electrolysis was performed was examined. As a result, only 12 μm was consumed, and the consumption rate was as slow as 0.4 μm / h.

< Reference Example 2>
As shown in FIG. 3A, the electrolytic cell 24 is connected to an ozone side gas / liquid separator 19, a hydrogen side gas / liquid separator 20, and a DC power source 21, and the anode chamber 3 is cooled with pure water as an electrolyte. The water was electrolyzed while supplying. The electrolytic current was 6.25A. However, two solid polymer electrolyte membranes 9 made of perfluorosulfonic acid cation exchange membranes used in the electrolytic cell 24 were used in an overlapping manner as shown in FIG.
Furthermore, when water supplied in circulation to the anode chamber 3 was mixed with carbon dioxide gas at 0.5 ml / min (approximately 2 vol% with respect to the amount of anode gas generated) and supplied, and pure water electrolysis was performed, The ozone generation current efficiency in the anode 23 was 40%, the hydrogen gas concentration contained in the anode gas was 0.07 vol%, and the cell voltage was 12V.

  When 6.25 A was continuously supplied to the electrolysis cell 24 and continuous electrolysis was performed for 29 hours, the ozone generation current efficiency during this period was not significantly changed as 40 to 42%. After 29 hours, the electrolytic cell was disassembled, and when the consumption thickness of the perfluorosulfonic acid cation exchange membrane constituting the solid polymer electrolyte membrane 9 in the electrolysis part was examined, it was consumed by 60 μm. The speed was as slow as 2.1 μm / h. It was shown that the consumption of the perfluorosulfonic acid cation exchange membrane can be further suppressed as compared with the additive-free electrolysis. It was also shown that the addition of carbon dioxide gas had no effect on ozone generation.

<Example 3>
As shown in FIG. 3-2, the electrolytic cell 24 is connected to an ozone side gas-liquid separator 19, a hydrogen side gas-liquid separator 20, and a DC power source 21, and the anode chamber 3 is cooled with pure water as an electrolyte. The water was electrolyzed while supplying. The electrolytic current was 6.25A. However, two solid polymer electrolyte membranes 9 made of perfluorosulfonic acid cation exchange membranes used in the electrolytic cell 24 were used in an overlapping manner as shown in FIG.

  Furthermore, pure water electrolysis is performed by mixing and supplying 2 ml / min (approximately 8 vol% of the amount of anode gas generated) of hydrogen gas generated at the cathode 23 to the water circulated and supplied to the anode chamber 3. As a result, the ozone generation current efficiency in the anode 22 was 40%, the hydrogen gas concentration contained in the anode gas was 0.07 vol%, and the cell voltage was 12V.

  When 6.25 A was continuously supplied to the electrolysis cell 24 and continuous electrolysis was performed for 29 hours, the ozone generation current efficiency during this period was not significantly changed as 40 to 42%. After 29 hours, the electrolytic cell 24 was disassembled and the consumption thickness of the perfluorosulfonic acid cation exchange membrane in contact with the anode was examined. As a result, only 6 μm was consumed, and the consumption rate was 0.2 μm / h. It was late. The perfluorosulfonic acid cation exchange membrane in contact with the cathode was not consumed or deteriorated.

<Example 4>
As shown in FIG. 3C, the electrolytic cell 24 is connected to the ozone side gas / liquid separator 19, the hydrogen side gas / liquid separator 20, and the DC power source 21, and the anode chamber 3 is cooled with pure water as an electrolyte. The water was electrolyzed while supplying. The electrolytic current was 6.25A. However, two solid polymer electrolyte membranes 9 made of perfluorosulfonic acid cation exchange membranes used in the electrolytic cell 24 were used in an overlapping manner as shown in FIG.
Furthermore, when 0.5 g / L of isopropyl alcohol was mixed and supplied to the water circulated and supplied to the anode chamber and pure water electrolysis was performed, the ozone generation current efficiency at the anode was 40%, and the anode gas The hydrogen gas concentration contained was 0.07 vol% and the cell voltage was 12V.

  When 6.25 A was continuously supplied to the electrolysis cell 24 and continuous electrolysis was performed for 29 hours, the ozone generation current efficiency during this period was not significantly changed as 40 to 42%. After 29 hours, the electrolytic cell 24 was disassembled, and the consumption thickness of the film where electrolysis was performed was examined. As a result, the consumption was 60 μm, but the consumption rate was as slow as 2.1 μm / h.

<Example 5>
As shown in FIG. 3-4, the electrolytic cell 24 is connected to an ozone side gas-liquid separator 19, a hydrogen side gas-liquid separator 20, and a DC power source 21, and the anode chamber 3 is cooled with pure water as an electrolyte. The water was electrolyzed while supplying. The electrolytic current was 6.25A. However, the solid polymer electrolyte membrane 9 made of a perfluorosulfonic acid cation exchange membrane used in the electrolytic cell 24 was used as a single sheet as shown in FIG. 2-1.
Further, 5 ml / min of carbon dioxide gas was supplied to the cathode chamber 3. As for the initial performance, the ozone generation current efficiency at the anode 22 was 40%, the hydrogen gas concentration contained in the anode gas was 0.07 vol%, and the cell voltage was 12V.

  When 6.25 A was continuously supplied to the electrolysis cell 24 and continuous electrolysis was performed for 29 hours, the ozone generation current efficiency during this period was not significantly changed as 40 to 42%. After 29 hours, the electrolysis cell 24 was disassembled, and the consumption thickness of the film where electrolysis was performed was examined. As a result, it was consumed 40 μm, but the consumption rate was as slow as 1.4 μm / h.

<Comparative Example 1>
As shown in FIG. 3A, the electrolytic cell 24 is connected to the ozone-side gas-liquid separator 19, the hydrogen-side gas-liquid separator 20, and the DC power source 21, and the anode chamber 3 is cooled with pure water as an electrolyte. Water electrolysis was performed while supplying. The electrolytic current was 6.25A. However, two perfluorosulfonic acid cation exchange membranes 9 used in the electrolytic cell 24 were used in an overlapping manner as shown in FIG.
A mixed gas of ozone and oxygen is generated from the anode, and hydrogen gas is generated from the cathode. The ozone generation current efficiency at the anode is 40%, the concentration of hydrogen gas contained in the anode gas is 0.07 Vol%, and the cell voltage is 13V. It was.

  When 6.25 A was continuously supplied to the electrolysis cell 24 and continuous electrolysis was performed for 29 hours, the ozone generation current efficiency during this period was not significantly changed as 40 to 42%. In addition, the hydrogen gas concentration contained in the anode gas was not clearly increased and was 0.07 vol% after 12 hours, 0.09 vol% after 24 hours, and 0.10 vol% after 29 hours. However, when the electrolytic cell 24 was disassembled after 29 hours and the consumption thickness of the perfluorosulfonic acid cation exchange membrane in contact with the anode for electrolysis was examined, it was consumed as much as 96 μm. The speed was as fast as 3.3 μm / h. Of the two perfluorosulfonic acid cation exchange membranes, the perfluorosulfonic acid cation exchange membrane on the side in contact with the cathode was not consumed or deteriorated.

  However, when 6.25 A was further supplied to the electrolysis cell 24 and continuous electrolysis was performed for a total of 58 hours, the ozone generation current efficiency during this period did not vary greatly as 40-42%. At this time, the concentration of hydrogen gas contained in the anode gas was not increased with time, and was 0.10 vol% 29 hours after the start of electrolysis as described above, but after 0.10 vol% after 5 hours. No increase was observed. However, the thickness of the perfluorosulfonic acid cation exchange membrane in contact with the anode decreases with time, and the consumption rate is 3.3 μm / h in 0-29 hours and 3.3 μm / h in 29-58 hours. It was shown that the consumption rate of the cation exchange membrane does not change and the consumption of the cation exchange membrane proceeds. The consumption amount of the cation exchange membrane was 180 μm.

  According to the ozone generation method and the ozone generation apparatus according to the present invention, the consumption of the perfluorosulfonic acid cation exchange membrane can be suppressed, ozone can be stably generated for a long time, and the sterilization / decolorization method using ozone is the above. It can be used in sewer facilities.

1: Anode chamber outlet 2: Cathode chamber outlet 3: Anode chamber 4: Cathode chamber 5: Anode feeding terminal 6: Cathode feeding terminal 7: Anode chamber feeding port 8: Cathode chamber feeding port 9: Perfluorosulphonic acid positive Solid polymer electrolysis chamber diaphragm 10 made of an ion exchange membrane: conductive diamond film 11: p-type silicon substrate 12 with projections and depressions: through-hole 13: cathode sheet 14: cathode current collector 15: sealing material 16: clamping bolt 17: Nut 18: Press plate 19: Ozone side gas / liquid separator 20: Hydrogen side gas / liquid separator 21: DC power source for electrolysis 22: Anode 23: Cathode 24: Electrolysis cell 25: Convex part 26: Concave part

Claims (8)

The anode and cathode are adhered to both sides of the solid polymer electrolyte membrane, a perfluorosulfonic acid cation exchange membrane is used as the solid polymer electrolyte membrane, and an electrode having conductive diamond on the surface is used as the anode. In the ozone generation method in which water is electrolyzed by supplying pure water to the cathode and supplying a direct current between the anode and cathode, ozone is generated from the anode chamber, and hydrogen is generated from the cathode chamber. ozone generating method is characterized in that feeding at least one kind selected from water Moto及 beauty organics. The anode and cathode are adhered to both sides of the solid polymer electrolyte membrane, a perfluorosulfonic acid cation exchange membrane is used as the solid polymer electrolyte membrane, and an electrode having conductive diamond on the surface is used as the anode. Supplying pure water to the anode chamber by electrolyzing the water by supplying a direct current between the positive and negative electrodes, generating ozone from the anode chamber, and generating hydrogen from the cathode chamber as a source of hydrogen, using hydrogen gas or catholyte which the hydrogen gas has been dissolved were generated in the cathode chamber, characterized in that the catholyte is supplied to the anode chamber from the outside of the anode chamber ozone generation method. The anode and cathode are adhered to both sides of the solid polymer electrolyte membrane, a perfluorosulfonic acid cation exchange membrane is used as the solid polymer electrolyte membrane, and an electrode having conductive diamond on the surface is used as the anode. In an ozone generation method in which pure water is supplied to the cathode and a direct current is supplied between the positive and negative electrodes to electrolyze the water, thereby generating ozone from the anode chamber and generating hydrogen from the cathode chamber. Supplying at least one selected from carbon dioxide and organic matter, and supplying at least one selected from carbon dioxide and organic matter through the perfluorosulfonic acid cation exchange membrane from the cathode chamber to the anode chamber features and to Luo Zon generation method to.   The ozone generation method according to claim 1 or 3, wherein alcohol is used as the organic substance. The anode compartment, an ozone generator used in the ozone generating method according to claim 1, characterized in providing at least one kind selected from water Moto及 beauty organics.   The ozone generator used in the ozone generating method according to claim 2, wherein hydrogen gas generated in the cathode chamber or catholyte in which the hydrogen gas is dissolved is used as a supply source of hydrogen supplied to the anode chamber. .   Supplying at least one selected from carbon dioxide and organic matter to the cathode chamber, allowing at least one selected from carbon dioxide and organic matter to pass through a perfluorosulfonic acid cation exchange membrane from the cathode chamber, and The ozone generation apparatus used for the ozone generation method according to claim 3, wherein the ozone generation apparatus is supplied to the anode chamber.   4. An ozone generator for use in the ozone generation method according to claim 1, wherein alcohol is used as the organic substance.

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