Liquid containing ozone, manufacturing method of liquid containing ozone

Abstract

To provide a liquid containing ozone with high transparency in a prescribed wavelength range regardless of concentration of the ozone.SOLUTION: A liquid containing ozone includes at least ozone and a plurality of air bubbles retained in the liquid. In the liquid, a cumulative 50% grain diameter D50 is less than 1 μm, on a volume basis of air bubbles with a particle size distribution of a diameter of an air bubble as a statistical population with regard to the plurality of air bubbles contained per a unit volume of the liquid. In the liquid, the maximum molar absorption coefficient absorbancy is less than 0.05, in a wavelength range of 380 to 750 nm, inclusive.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to ozone-containing liquids and methods for producing ozone-containing liquids. [Background technology]

[0002] In recent years, the use of ozone for the purification and decolorization of wastewater has been widely attempted because ozone has deodorizing and purifying properties and does not require the use of environmentally polluting chemicals. It is generally known that ozone water, in which ozone is dissolved, becomes more bluish as the concentration increases. Therefore, when bluish ozone water is used for purification or decolorization, the blue color of the ozone water makes it difficult to visually determine the degree of purification or decolorization. Therefore, in order to produce ozone water with high transparency in a specified wavelength band regardless of the ozone concentration, a technology is known in which bittern (MgCl2) is added to ozone water to combine the bittern components with ozone (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-154076 Summary of the Invention [Problem to be solved by the invention]

[0004] However, bittern components are chemicals with strong deliquescence and alkalinity. Therefore, there is a possibility that metal corrosion may occur due to the deliquescence of the bittern components, and the alkalinity of the bittern components may have an impact on the environment. Therefore, when the ozonated water of Patent Document 1 is used for wastewater treatment or decolorization treatment, it is necessary to recover the bittern components after the treatment.

[0005] An object of the present invention is to provide an ozone-containing liquid that has high transparency in a predetermined wavelength band regardless of the ozone concentration, without the addition of any chemicals. [Means for solving the problem]

[0006] In order to solve the above problems, an ozone-containing liquid according to one embodiment of the present disclosure contains at least ozone and a plurality of bubbles retained in the liquid, and a D50 of a bubble diameter, which is a population based on a particle size distribution of the bubble diameters of the plurality of bubbles contained per unit volume of the liquid, is less than 1 μm; The liquid is characterized by having a molar absorption coefficient of less than 30 at the wavelength exhibiting maximum absorbance in the wavelength range of 380 nm or more and 750 nm or less. [Effects of the Invention]

[0007] According to at least one aspect of the present disclosure, it is possible to provide a liquid containing ozone that has high transparency in a predetermined wavelength band, regardless of the ozone concentration. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram for explaining the method for producing ozone water using an atomized bubble generator. FIG. [Figure 2] 1 is a diagram showing an example of an ozone water production apparatus according to a first embodiment. [Figure 3] 2A to 2C are diagrams illustrating the manufacturing steps of the ozone water manufacturing apparatus according to the first embodiment. [Figure 4] Schematic diagram of an atomization bubble generator. [Figure 5] FIG. 10 is a diagram showing an example of an ozone water production apparatus according to a first modified example. [Figure 6] FIG. 1 is a diagram showing an example of an ozone water production apparatus. [Figure 7] FIG. 1 is a diagram showing an example of an ozone water production apparatus. [Figure 8] FIG. 1 is a diagram showing an example of an ozone water production apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments according to the present disclosure will be described. Note that the following embodiments are merely examples and are not intended to limit the ideas of the present disclosure more than necessary.

[0010] It is generally known that in ozone-containing liquids, which are produced by dissolving ozone in a liquid, the distance between ozone molecules becomes shorter and the molecules have a structural property that causes light absorption at specific wavelengths, resulting in a bluish color, known as ozone blue.

[0011] In particular, when ozone is dissolved in water at a high concentration, the frequency of intermolecular structural interactions between ozone molecules increases, resulting in greater light absorption and a stronger blue tint. However, when used in wastewater treatment or decolorization treatment, the blue color can make it difficult to visually determine the degree of purification or decolorization. To solve the above problem, the inventors conducted detailed studies on the dissolution of ozone into liquids. As a result of their studies, they confirmed that the following configuration can provide ozone water with high transparency regardless of the concentration.

[0012] That is, the present invention provides an ozone-containing liquid, which contains at least ozone and a plurality of bubbles retained in the liquid, and in which the D50 of the bubble diameter, which is the population of the particle size distribution of the bubble diameters of the plurality of bubbles contained per unit volume of the liquid, is less than 1 μm. With this configuration, the liquid is characterized by an absorbance of less than 0.05 in the wavelength range of visible light (wavelength band of 380 nm to 750 nm). The liquid is also characterized by a maximum molar absorption coefficient of less than 30. The ozone-containing liquid provided by the present invention contains so-called ultrafine bubbles, which are bubbles with a D50 of less than 1 μm. With this configuration, fewer bubbles rise from the liquid and escape into the gas phase, and the bubbles stably retained in the liquid prevent the ozone molecules from having any structure and becoming colored, which is considered to result in high transparency in a predetermined wavelength range.

[0013] In ozone-containing liquids containing many bubbles with diameters of 1 μm or larger, the bubbles may rise to the surface and disappear over time, resulting in the ozone escaping into the air layer. Furthermore, when bubbles with diameters of 1 μm or larger disappear, bubbles smaller than 1 μm also disappear. This results in a closer distance between the dissolved ozone molecules, resulting in a stronger blue color. Therefore, we determined that minimizing bubbles with diameters of 1 μm or larger is important for producing a highly transparent, nearly colorless ozone-containing liquid, regardless of concentration. Regarding bubble size, a device using an advanced scattered light intensity tracking method is preferable; in this study, we used a Shimadzu measuring instrument (model number SALD-7500).

[0014] [First embodiment] An example of a method for producing an ozone-containing liquid according to the first embodiment will be described below with reference to Fig. 1. Fig. 1(a) is a schematic diagram of an apparatus 100 for producing an ozone-containing liquid. The apparatus 100 includes an atomized bubble generator 101, an ozone generator 102, and a collection container 106. The apparatus 100 also holds a desired liquid inside the collection container 106.

[0015] The ozone-containing liquid obtained by the device 100 is obtained by carrying out a generation process in which ultrasonic waves are applied to the liquid in the collection container 106 to atomize the liquid and generate droplets containing fine bubbles, a process in which the atomized droplets are introduced into the ozone space in which ozone has been generated to bring them into contact with ozone, and a recovery process in which the atomized liquid after introduction is recovered by a recovery mechanism including a collection container.

[0016] Specifically, in the droplet generation process, ultrasonic waves are irradiated into the liquid by the atomization bubble generator 101, which generates bubbles by atomizing the liquid. This causes molecules in the liquid to vibrate in the direction of sound propagation, resulting in alternating high and low pressure regions. In the low-pressure region, the pressure of the liquid molecules becomes lower than the vapor pressure, generating bubbles 103, which are dissolved gas bubbles, as shown in Figure 1(b). Some of the bubbles generated in the liquid repeatedly expand and contract under the influence of the ultrasonic waves, forming bubbles through association with each other and being released from the liquid. Others are crushed by the vibrations caused by the ultrasonic waves. Therefore, it is thought that small bubbles, specifically ultrafine bubbles with particle sizes less than 1 μm, tend to remain in the liquid.

[0017] The atomization phenomenon occurs at the gas-liquid interface by the atomization bubble generator 101 because, as shown in Figure 1(c), surface waves are formed, and when the vibration amplitude of the surface waves exceeds a critical point, one of the wave crests breaks, generating small droplets, causing atomization. The "atomization" referred to here refers to the generation of bubble-containing droplets 104, which are tiny mist-like liquids.

[0018] When atomization is performed at the gas-liquid interface using the atomization bubble generator 101, the liquid containing bubbles is atomized and droplets are generated at the same time, resulting in a significant pressure relief effect. Therefore, new bubbles are generated during atomization, and droplets containing the newly generated bubbles are generated. If the atomized droplets are small, large bubbles cannot exist within the droplets, resulting in the selective generation of small bubbles, so-called ultrafine bubbles. To produce a liquid containing ozone, the atomization that generates droplets containing the bubbles is performed in a space containing ozone gas, making it possible to produce the desired ozone-containing liquid.

[0019] Although there are no particular limitations on the gas used to generate ozone-containing gas, it is preferable to provide an ozone gas generation unit 102, which produces ozone gas by discharge or ultraviolet irradiation, inside the collection container 106, and create an ozone-containing atmosphere inside the collection container 106. Creating an ozone-containing atmosphere is preferable because it reduces the risk of generating nitrogen oxides when ozone gas is produced by ultraviolet irradiation in the atmosphere. The light source is preferably a lamp capable of emitting light at wavelengths absorbed by oxygen molecules, more preferably a lamp capable of emitting light at wavelengths of 240 nm or less. Known light sources can also be used. For example, low-pressure mercury lamps using quartz glass are typical, but recent mercury-free ozone lamps can also achieve similar effects. Specific examples include excimer lamps and CARE222 (manufactured by Ushio Inc.). Naturally, to avoid blocking light of these wavelengths, transparent materials such as quartz glass can be used as components in the optical path.

[0020] Furthermore, when the production of the desired ozone-containing liquid is completed, the ozone in the recovery mechanism can be quenched using known chemical methods such as using manganese catalysts or activated carbon, etc. However, one preferred embodiment is to deactivate the ozone in the recovery mechanism by irradiating it with a general-purpose germicidal lamp capable of emitting light with a wavelength of 254 nm, which is the absorption wavelength of ozone.

[0021] It is preferable to use an ozone-resistant material for the liquid-contacting member with the ozone-containing UFB (Ultra Fine Bubble) liquid after ultraviolet irradiation. Examples of ozone-resistant materials include titanium for metals, fluorine-based polymers (such as PFA (perfluoroalkoxyalkane) and PTFE (polytetrafluoroethylene)) for resins, and quartz for glass.

[0022] 2 shows an overview of an apparatus similar to the apparatus 100 in FIG. 1(a), in which a collection container 106 for collecting ozone-containing liquid is sealed and the entire apparatus is covered. FIG. 3 is a schematic diagram of the steps for producing an ozone-containing liquid using the apparatus 100 in FIG. 1(a), in which droplets containing bubbles with a D50 of 1 μm or less are generated by irradiating the liquid with ultrasound, and the collection container 106 is filled with an ozone atmosphere by the ozone gas generation unit 102. At the same time, the generated droplets are not leaked to the outside, and can be collected as an ozone-containing liquid containing bubbles with a D50 of 1 μm or less.

[0023] In the case of using the ozone gas generation unit 102 to irradiate a liquid with ultrasonic waves to atomize it, the thickness of the liquid placed on the vibrator is preferably 15 cm or less, depending on the output and strength of the vibrator that irradiates the ultrasonic waves. If the thickness of the liquid exceeds 15 cm, the intensity of the ultrasonic irradiation required for atomization increases, raising concerns about its effect on the liquid medium. Taking water as a specific example of the liquid, there is a concern that water molecules may become hydroxyl radicals and react with, for example, dissolved nitrogen in the atmosphere to generate nitrogen oxide ions. Furthermore, the atomized liquid can be recovered by contact or collected in a specific location using a fan or the like.

[0024] [Variation 1] The method for producing an ozone-containing liquid by applying ultrasonic vibrations is not limited to the above. Here, Modification 1 will be described with reference to FIG. 4. FIG. 4(a) is a perspective view of a device 201 that generates bubbles by vibrations caused by ultrasonic waves, and FIG. 4(b) is a top view of the device 201 that generates bubbles. As shown in FIG. 4(a), the atomization bubble generator 201 has fine holes (mesh 202) in the center of its top surface. These holes are connected to the bottom side of the atomization bubble generator 201, and liquid is supplied from the bottom side by capillary force or the like. When ultrasonic vibrations are applied to this supplied liquid by a vibrator 203 provided around the mesh 202, fine droplets are generated (so-called atomization). At this time, it is thought that dissolved gas contained in the liquid becomes small bubbles due to a sudden pressure change caused by the ultrasonic vibrations. It is also thought that bubbles are generated by the inclusion of gas in the space when the liquid becomes fine droplets (atomization).

[0025] As shown in FIG. 4, the desired ozone water can be produced by using an ozone-containing gas in a collection container, similar to the apparatus 100 of the first embodiment for producing ozone water. A downward atomization direction is effective because the atomized liquid falls under its own weight and can be collected, but upward or horizontal directions are also acceptable. To prevent bubbles from escaping and diffusing from the liquid, the average relative humidity derived from the droplet components in the space can be set to 80% or higher, which is expected to prevent diffusion. If this average value is less than 80%, the amount of liquid recovered will be small due to evaporation of the bubble-containing droplets, resulting in a reduced recovery rate. Furthermore, if the weight ratio of the bubble-containing liquid to the raw liquid is less than 80%, there is a concern that the atomized droplets may leak out of the production apparatus, resulting in a reduced yield.

[0026] The following describes humidity. The humidity described in this specification is relative humidity, with 0% being the relative humidity when the target gas component is completely absent from the collection mechanism, and 100% being the humidity when the target gas component condenses within the collection mechanism. If the target liquid is water, it can be measured using a general-purpose hygrometer. However, if the target liquid is something other than water, it is necessary to confirm that the target liquid component is not present in the collection container at the start of ozone water production. A useful method for this confirmation is to use a gas detector tube for the target liquid component. After confirmation, ozone water production begins, and the state in which condensation occurs within the collection mechanism is considered to be a state in which the target liquid has a relative humidity of 100%. Therefore, from this state onward, the state of 100% relative humidity will continue while the ozone water is produced by atomization with power applied. The term "average relative humidity" used in this specification refers to the average relative humidity in the space of the collection mechanism from the start to the end of ozone water production at room temperature and pressure of 25°C and 1 atmosphere.

[0027] (Explanation of specific embodiments) Hereinafter, ozone water was produced using the ozone water production apparatus shown in the above figures under various production conditions, and the results of verifying the produced ozone water will be described.

[0028] The ozone concentration in the ozone water was quantified using a Pack Test manufactured by Kyoritsu Chemical Research Institute. Furthermore, a measuring instrument (model number SALD-7500) manufactured by Shimadzu Corporation was used to measure the bubbles in the produced ozone water. The raw material liquid before the fine bubbles were generated was used for comparison. The cumulative 50% particle diameter based on volume of the bubbles contained in the ozone water was used as D50. Similarly, the cumulative 90% particle diameter was used as D90.

[0029] The analysis was performed using a Biochecker manufactured by San-ai Oil Co., Ltd. The absorbance was measured using an absorption spectrophotometer. The evaluation criteria are as follows: A...less than 0.05 C: 0.05 or more and less than 0.1 D...0.1 or more

[0030] The molar extinction coefficient ε was calculated based on the Lambert-Beer formula (i) from the absorbance measured using an absorptiometer. The concentration C used in this calculation was the value obtained from the above pack test. A=-log10(I1 / I0)=εcl···(i)

[0031] In equation (i), A is absorbance, I0 is the intensity of light before it enters the medium (irradiance), I1 is the intensity of light after it has passed through a medium of length l, ε is the molar absorption coefficient, and c is the molar concentration of the medium. The evaluation criteria for the molar absorption coefficient (L mol-1 cm-1) are shown below. If it is A, the color is barely visible to the naked eye. A...Under 30 B: Between 30 and 35 C: 35 or more and less than 100 D...100 or more

[0032] The ozone concentration in the liquid was verified. The dissolved ozone concentration in the FB-containing liquid before production and after storage was determined based on a color reaction caused by oxidative coupling with Trinder's reagent. When the upper limit of the measured concentration was reached, the solution was diluted with ultrapure water and converted to a concentration. The test solution was sealed in a PFA container without a gas phase and stored at room temperature for one week. The ozone concentration at the time of production of the ozone-containing liquid was compared with the ozone concentration one week after production. The evaluation criteria for ozone concentration over time are as follows: The initial ozone concentration was defined as C0, and the ozone concentration 10 days after production was defined as C10. The change in ozone concentration was calculated using C10 / C0 x 100. A: 80% or more B: Between 60% and 80% C: 10% or more but less than 60% D: Less than 10%

[0033] The bactericidal effect of ozone water was also verified. Specifically, a comparative test was conducted using a biochecker when ozone water was added to a suspension containing Escherichia coli and Staphylococcus aureus, and compared with ultrapure water. The evaluation criteria are as follows: A: 99% or more B: 80% or more, less than 99% C: 50% or more, less than 80% D: Less than 50%

[0034] Example 1 Ozone water was produced using the device 100 shown in Figure 2. A piezoelectric atomizing element (1.6 MHz) manufactured by Seiko Giken was used as the atomized bubble generator 101. The atomized bubble generator 101 was placed in a glass container 106, and 500 ml of ultrapure water was poured into it. The height at which the atomized bubble generator 101 was installed was adjusted so that the distance between the gas-liquid interface and the piezoelectric element surface was 4.0 cm. An ozone generator 102 was installed inside the container. The airborne ozone concentration was measured using an ozone gas detector tube 1 minute after ozone gas production and was found to be 20 ppm. The average relative humidity (referred to as the average relative humidity) in the collection container during production was 85%. The ozone concentration in the liquid was 1.5 ppm. Unless otherwise specified in the following examples, the average relative humidity is 80% or higher.

[0035] Example 2 As in Example 1, the device 600 shown in Figure 6 was used, and a Seiko Giken piezoelectric atomization element (1.6 MHz) was used as the piezoelectric element for generating ultrasound. The piezoelectric element was placed in a glass container 107, and 300 ml of ultrapure water was poured into it. The height at which the piezoelectric element was installed was adjusted so that the distance between the gas-liquid interface and the piezoelectric element surface was 3.5 cm. The air ozone concentration at this time was measured using an ozone gas detector tube 1 minute after ozone gas production and was found to be 20 ppm. Ozone water was produced using a configuration in which the liquid atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 90%. The ozone concentration in the liquid was 1.5 ppm.

[0036] Example 3 Ozone water was produced using the same device as in Example 1. The air ozone concentration was measured using an ozone gas detector tube one minute after the production of ozone gas and was found to be 50 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 85%. The ozone concentration in the liquid was 5 ppm.

[0037] Example 4 Ozone water was produced using the same device as in Example 2. The air ozone concentration was measured using an ozone gas detector tube one minute after the production of ozone gas and was found to be 50 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 90%. The ozone concentration in the liquid was 5 ppm.

[0038] Example 5 Ozone water was produced using the same device as in Example 1. The air ozone concentration was measured using an ozone gas detector tube one minute after the production of ozone gas and was found to be 100 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 85%. The ozone concentration in the liquid was 13 ppm.

[0039] Example 6 Ozone water was produced using the same device as in Example 2. The air ozone concentration was measured using an ozone gas detector tube one minute after the production of ozone gas and was found to be 100 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 90%. The ozone concentration in the liquid was 13 ppm.

[0040] Example 7 Ozone water was produced using the same device as in Example 1. The air ozone concentration was measured using an ozone gas detector tube one minute after the production of ozone gas and was found to be 180 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 85%. The ozone concentration in the liquid was 50 ppm.

[0041] Example 8 Ozone water was produced using the same device as in Example 2. The air ozone concentration was measured using an ozone gas detector tube one minute after the production of ozone gas and was found to be 180 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 90%. The ozone concentration in the liquid was 50 ppm.

[0042] Example 9 Ozone water was produced using the same device as in Example 1. The air ozone concentration was measured using an ozone gas detector tube one minute after the production of ozone gas and was found to be 200 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 90%. The ozone concentration in the liquid was 70 ppm.

[0043] Example 10 Ozone water was produced using the same device as in Example 2. The air ozone concentration was measured using an ozone gas detector tube one minute after the production of ozone gas and was found to be 200 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 99%. The ozone concentration in the liquid was 70 ppm.

[0044] Example 11 Ozone water was produced using the same device as in Example 1. The air ozone concentration was measured using an ozone gas detector tube 30 seconds after the production of ozone gas and was found to be 200 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 90%. The ozone concentration in the liquid was 100 ppm.

[0045] Example 12 Ozone water was produced using the same device as in Example 2. The air ozone concentration was measured using an ozone gas detector tube 30 seconds after the production of ozone gas and was found to be 200 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 99%. The ozone concentration in the liquid was 100 ppm.

[0046] Example 13 Ozone water was produced using the same device as in Example 2. The gas in the container was replaced with oxygen during this process. The ozone concentration in the air was measured 10 seconds after the production of ozone gas using an ozone gas detector tube and was found to be 200 ppm. Ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 99%. The ozone concentration in the liquid was 500 ppm.

[0047] Example 14 Ozone water was produced using the device 500 shown in Figure 5. A transducer used in an ultrasonic humidifier was used as the atomization bubble generator. The air ozone concentration was measured using an ozone gas detector tube one minute after the ozone gas was produced and was found to be 180 ppm. The ozone water was produced using a configuration in which the liquid that was atomized and released into the ozone space was collected. The average relative humidity in the collection container during production was 99%. The ozone concentration in the liquid was 50 ppm.

[0048] Example 15 Ozone water was produced using the same device as in Example 14. The gas in the container was replaced with oxygen during this process. The ozone concentration in the air was measured using an ozone gas detector tube 10 seconds after the ozone gas was produced and was found to be 200 ppm. Ozone water was produced using a system that collected the liquid that had been atomized and released into the ozone space. The average relative humidity in the collection container during production was 99%. The ozone concentration in the liquid was 500 ppm.

[0049] (Comparative Example 1) In Example 1 (see FIG. 2), ozone water production was attempted in a state where outside air could be taken into the collection container 106 to improve air circulation. The local relative humidity was 81%. The relative humidity in the space where the liquid was atomized and diffused was 40% in the initial state, and the average relative humidity during production was 78%. Using such a device, an attempt was made to produce ozone water, but collection was difficult.

[0050] (Comparative Example 2) In Example 1, the height at which the piezoelectric element was installed was adjusted so that the distance between the gas-liquid interface and the surface of the piezoelectric element was 30 cm. Except for this, an attempt was made to produce ozone water in the same manner as in Example 1. Furthermore, no formation of a water column or opacification of the gas phase was observed at the liquid-gas interface, and no microdroplets were generated.

[0051] (Comparative Example 3) In Example 4, the piezoelectric element was changed to a 267 Hz probe type. Except for this, an attempt was made to produce a liquid containing fine gas bubbles in the same manner as in Example 4. At the liquid-gas interface, the formation of a water column and opacification of the gas phase were not observed, and no microdroplets were generated.

[0052] Comparative Example 4 Ozone water was produced by injecting high-concentration ozone gas from the outside using a device 700 as shown in Figure 7. A bubble atomization device 301 was installed, with the bubble atomization device connected to the exhaust port. Specifically, the gas phase and the aqueous phase were separated by a microporous membrane, and the gas phase side was pressurized using an air pump. Air was introduced through the microporous membrane, and ozone bubbling was performed to produce ozone water. A filter membrane with a molecular weight cutoff of 1000 (Minimate, manufactured by Nippon Pall) was used as the microporous membrane. The ozone concentration in the liquid was 1.5 ppm.

[0053] (Comparative Example 5) Ultrapure water was placed in a collection container 106, similar to the apparatus 800 shown in Figure 8, and an ozone gas generator 102 was attached to the top, replacing the air with oxygen. Three hours after generating ozone gas, pressure was applied from the gas side to prevent interference with the ozone gas generator, dissolving the ozone gas. This process was repeated 10 times to produce ozone water. The ozone concentration in the liquid was 70 ppm.

[0054] Below, a table summarizing the above examples and comparative examples is provided.

[0055] [Table 1]

[0056] [Table 2]

Claims

1. A liquid containing ozone, the liquid containing at least ozone and a plurality of bubbles retained in the liquid, wherein D50, which is a volume-based cumulative 50% particle size of bubbles based on a particle size distribution of bubble diameters of a plurality of bubbles contained per unit volume of the liquid, is less than 1 μm; A liquid characterized by having an absorbance of less than 0.05 in the wavelength band of 380 nm or more and 750 nm or less.

2. A liquid containing ozone, the liquid containing at least ozone and a plurality of bubbles retained in the liquid, wherein D50, which is a volume-based cumulative 50% particle size of bubbles based on a particle size distribution of bubble diameters of a plurality of bubbles contained per unit volume of the liquid, is less than 1 μm; A liquid characterized by having a maximum molar absorption coefficient of less than 30 in the wavelength range of 380 nm or more and 750 nm or less.

3. 3. The liquid according to claim 1, wherein the ozone concentration in the liquid containing ozone is 60% or more one week after preparation compared to the concentration at the time of preparation.

4. The liquid according to claim 1 or 2, characterized in that D90, which is the cumulative 90% particle size based on volume of bubbles in a population based on the particle size distribution of the bubble diameters of a plurality of bubbles in the ozone-containing liquid, is less than 1 μm.

5. 3. The liquid according to claim 1, wherein the ozone-containing liquid has an ozone concentration of 5 ppm or more.

6. 3. The liquid according to claim 1, wherein the ozone-containing liquid has an ozone concentration of 13 ppm or more.

7. 3. The liquid according to claim 1, wherein the ozone-containing liquid has an ozone concentration of 50 ppm or more.

8. 3. The liquid according to claim 1, wherein the ozone-containing liquid has an ozone concentration of 70 ppm or more.

9. a generating step of atomizing a liquid by irradiating it with ultrasonic waves to generate droplets containing fine bubbles; contacting the droplets with ozone; a collecting step of collecting the droplets into a collection container by a collection mechanism including the collection container; A method for producing an ozone-containing liquid, comprising the step of obtaining the liquid according to claim 1 or 2 through the recovery step.

10. The generating step includes: A generating device including a mesh and a vibrator is used, 10. The method for producing a liquid according to claim 9, wherein the bubbles are generated by supplying a liquid to the mesh and irradiating the supplied liquid with ultrasonic waves by the vibrator.

11. 10. The method for producing a liquid according to claim 9, wherein the average relative humidity inside the collection container is 80% or more, assuming that the humidity at the time of condensation of the liquid is 100%.

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