Liquid containing ozone with suppressed dispersion of ozone into gas phase, and method for producing liquid containing ozone

Abstract

The present invention provides a liquid containing ozone, wherein dispersion of ozone into a gas phase is suppressed regardless of the concentration of ozone. The liquid containing ozone according to the present invention contains at least ozone and a plurality of bubbles retained in the liquid, the liquid characterized in that D50, which is a volume-based cumulative 50% particle diameter of bubbles based on, as a parent population, a particle size distribution of bubble diameters of a plurality of bubbles contained per unit volume of the liquid, is less than 1 μm; and when the liquid is set in a container having an opening with an opening diameter of 10 cm so as to account for 50% or more of the capacity of the container, and the ozone gas concentration is measured at 25°C and 1 atm using a gas concentration meter disposed 3 cm above the opening in the vertical direction while the opening is opened, the ozone gas concentration in a space is less than 0.1 ppm.

Description

Ozone-containing liquid in which ozone dispersion into the gas phase is suppressed, and method for producing the ozone-containing liquid

[0001] The present disclosure relates to an ozone-containing liquid in which ozone dispersion into a gas phase is suppressed, and a method for producing an ozone-containing liquid.

[0002] In recent years, the use of ozone for purifying and decolorizing wastewater has been widely attempted because ozone has deodorizing and purifying effects and does not use chemicals that pollute the environment. However, ozone that disperses from the liquid into the gas phase may have adverse effects on the human body. Therefore, in order to produce odorless ozone water 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).

[0003] JP 2009-154076 A

[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 suppresses ozone from scattering into the gas phase regardless of the ozone concentration, without the addition of any chemical agent.

[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 has a D50, which is the cumulative 50% particle size on a volume basis of the bubbles, with the particle size distribution of the bubble diameters of the plurality of bubbles contained per unit volume of the liquid as a population, of less than 1 μm; and when the liquid is placed in a container having an opening with an opening diameter of 10 cm so that the volume of the container is 50% or more, and the opening is open, the ozone gas concentration in the space measured at 25°C and 1 atmosphere using a gas concentration meter positioned 3 cm vertically above the opening is less than 0.1 ppm.

[0007] According to at least one aspect of the present disclosure, it is possible to provide a liquid containing ozone in which ozone dispersion into the gas phase is suppressed regardless of the ozone concentration.

[0008] FIG. 1 is a diagram for explaining the ozone water production method using an atomized bubble generator. FIG. 2 is a diagram showing an example of an ozone water production apparatus according to a first embodiment. FIG. 3 is a diagram showing production steps of the ozone water production apparatus according to the first embodiment. FIG. 4 is a diagram showing an atomized bubble generator. FIG. 5 is a diagram showing an example of an ozone water production apparatus according to a first modified example. FIG. 6 is a diagram showing an example of an ozone water production apparatus. FIG. 7 is a diagram showing an example of an ozone water production apparatus. FIG. 8 is a diagram showing an example of an ozone water production apparatus.

[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] While ozone remains in the liquid, it does not diffuse into the gas phase, and ozone water does not emit an ozone odor. However, it naturally diffuses into the gas phase through an equilibrium reaction with the atmosphere, and regular ozone water emits an ozone odor. It is also known that ozone at concentrations of 0.1 ppm or higher can irritate the human nose and throat. It is known that ozone released from the liquid into the gas phase during sewage treatment or decolorization treatment has increasingly severe adverse effects on the human body as the concentration increases. Furthermore, in ozone water produced by dissolving ozone in a liquid through ozone gas bubbling, the ozone bubbles in the water are large, so ozone diffuses into the gas phase in a short period of time. It has also been found that if the bubble diameter is 1 μm or greater, ozone diffuses into the gas phase over time, generating an ozone odor. To solve the above problem, the inventors conducted detailed studies on ozone diffusion into the gas phase. As a result of their studies, they confirmed that ozone water can be provided that suppresses ozone dispersion into the gas phase by the following configuration.

[0011] That is, the ozone-containing liquid contains at least ozone and a plurality of bubbles retained in the liquid, and the D50 of the bubble diameter, which is determined based on 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, a container with an opening of 10 cm in diameter is filled with the ozone to 50% or more of the container's capacity. With the opening open, a gas concentration meter positioned 3 cm vertically above the opening measures an ozone gas concentration of less than 0.1 ppm in the space at room temperature and normal pressure. This is thought to be because the presence of so-called ultrafine bubbles, which have a D50 of less than 1 μm, reduces the number of bubbles that rise from the liquid and escape into the gas phase. The bubbles stably retained in the liquid suppress evaporation and the diffusion of ozone into the gas phase. Furthermore, if bubbles of 1 μm or larger are present, the ozone contained in the bubbles may diffuse into the gas phase as they disappear, or bubbles smaller than 1 μm may also be entrained and disappear as the ozone diffuses into the gas phase, further diffusing the ozone into the gas phase. Therefore, it was determined that minimizing bubbles of 1 μm or larger is important for providing odorless ozone water. Regarding bubble size, a device using a scattered light intensity tracking method is preferred, and in the embodiment described below, a nanoparticle size distribution analyzer (model number SALD-7500) manufactured by Shimadzu Corporation was used.

[0012] [First Embodiment] An example of a method for producing an ozone-containing liquid according to a first embodiment will now be described 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 generating device 101, an ozone generator 102, and a collection container 106. The apparatus 100 also holds a desired liquid inside the collection container 106.

[0013] 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, thereby obtaining the desired ozone-containing liquid.

[0014] 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-pressure 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 FIG. 1(b). Some of the bubbles generated in the liquid undergo repeated expansion and contraction due to the influence of ultrasonic waves, resulting in the formation of bubbles by association and release from the liquid. Other bubbles are crushed by the vibrations caused by the ultrasonic waves of the atomization bubble generator 101. Therefore, it is believed that small bubbles, specifically ultrafine bubbles with a diameter of less than 1 μm, tend to remain in the liquid.

[0015] The atomization phenomenon at the gas-liquid interface caused by the atomization bubble generator 101 is thought to occur because, as shown in Figure 1(c), surface waves are formed in the liquid, and when the vibration amplitude of the surface waves exceeds a critical point, one of the wave crests breaks, generating small droplets and causing atomization. The "atomization" referred to here refers to the generation of bubble-containing droplets 104, which are fine mist-like liquid.

[0016] When the atomization bubble generator 101 atomizes a liquid at the gas-liquid interface, the liquid containing gas bubbles is atomized and droplets are generated at the same time, resulting in a significant pressure relief effect. Therefore, new gas bubbles are generated during atomization, and droplets containing the newly generated gas bubbles are generated. If the atomized droplets are small, large gas bubbles cannot exist within the droplets, resulting in the selective generation of small gas bubbles, so-called ultrafine gas bubbles. To produce a liquid containing ozone, the desired ozone-containing liquid can be produced by performing the atomization that generates the droplets containing the gas bubbles in a space containing ozone gas.

[0017] To use an ozone-containing gas as the gas, although there are no particular limitations, it is preferable to provide an ozone gas generation unit 102 that produces ozone gas by discharge or ultraviolet irradiation within the collection container 106, thereby creating 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 with an absorption wavelength of oxygen molecules, more preferably a lamp capable of emitting light with a wavelength of 240 nm or less. Known light sources can also be used. For example, a low-pressure mercury lamp using quartz glass is a typical example, but a mercury-free ozone lamp can also achieve similar effects. Specific examples include excimer lamps and ultraviolet irradiation devices. Commercially available ultraviolet irradiation devices can also be used, such as an antiviral / sterilizing ultraviolet irradiation device (product name "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.

[0018] Furthermore, when the production of the desired ozone-containing liquid is completed, the ozone in the recovery mechanism can be quenched by known chemical methods such as using manganese catalysts or activated carbon, etc. However, it is also a preferred embodiment 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.

[0019] It is preferable to use an ozone-resistant material as a liquid-contacting member for the ozone-containing UFB (Ultra Fine Bubble) liquid after ultraviolet irradiation. Examples of ozone-resistant materials include titanium as a metal, fluorine-based polymers (such as PFA (perfluoroalkoxyalkane) and PTFE (polytetrafluoroethylene)) as a resin, and quartz as a glass.

[0020] 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 ultrasonic waves, 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 can be collected as an ozone-containing liquid containing bubbles with a D50 of 1 μm or less without leaking to the outside.

[0021] In the case of atomizing a liquid by irradiating it with ultrasonic waves, 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 for atomization increases, raising concerns about its impact on the liquid medium. If water is taken as a specific example of a liquid, there is a concern that hydroxyl radicals generated from water molecules may react with, for example, dissolved nitrogen in the atmosphere, resulting in the production of nitrogen oxides. Furthermore, recovery methods include contact recovery of the atomized liquid, or collection at a specific location using a fan or the like.

[0022] [Variation 1] The method of producing ozone water by applying ultrasonic vibrations is not limited to the above. Variation 1 will now be described with reference to FIGS. 4A and 4B. FIG. 4A is a perspective view of a device 201 that generates bubbles by vibrations caused by ultrasonic waves, and FIG. 4B is a top view of the device 201. As shown in FIG. 4A, a mesh 202, a fine hole, is located in the center of the top surface of the atomization bubble generator 201. 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 (e.g., stored in 204) by a vibrator 203 provided around the mesh 202, fine droplets are generated (so-called atomization). It is believed that dissolved gas contained in the liquid breaks down into tiny bubbles due to the sudden pressure change caused by the ultrasonic vibrations. It is also believed that bubbles are generated by the inclusion of gas in the air space during the formation of fine droplets (atomization).

[0023] As with the first embodiment of the apparatus 100 for producing ozone water shown in FIG. 4B , the desired ozone water can be produced by using an ozone-containing gas in a collection container. While a downward atomization direction is effective because the atomized liquid falls under its own weight and is collected, 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.

[0024] <Regarding the Liquid> The liquid to be atomized is not particularly limited to water, organic liquid, ionic liquid, etc., but water is preferred. There are no particular limitations on the means for supplying the liquid to be atomized by ultrasonic irradiation. For example, when water is used as the liquid to be atomized, water may be supplied to a tank in a batch system, water may be supplied through a pipe from a water pipe, or moisture in the air may be supplied as condensed water using a Peltier element or the like. If the liquid to be atomized by ultrasonic irradiation is shaken and stirred in a desired gas atmosphere, water with the desired gas dissolved therein is produced according to Henry's law. In an oxygen atmosphere, water containing 45 ppm of oxygen is produced. On the other hand, in the atmosphere, water with approximately 8.4 ppm of dissolved oxygen can be produced at room temperature.

[0025] Examples of water include purified water with high purity (ultrapure water), tap water, and hard water. These waters may also contain solutes that dissolve in them (e.g., electrolytes formed by dissociation of sodium chloride, silver nitrate, etc., free chlorine, amino acids, sugars, buffers, dyes, etc.), and may also contain dispersants (e.g., pigments, dispersants, cells, bubbles, emulsions, titanium oxide, emulsifiers, etc.).

[0026] A mixture of water and a water-soluble organic solvent can also be used. The water-soluble organic solvent to be used is not particularly limited, but specific examples include the following: alkyl alcohols having 1 to 4 carbon atoms, amides, ketones or keto alcohols, cyclic ethers, glycols, lower alkyl ethers of polyhydric alcohols, polyalkylene glycols, and triols.

[0027] The water-soluble organic solvents listed above may be used alone or in combination of two or more.

[0028] Furthermore, as the liquid for the gas dissolving solution, it is also possible to use a liquid derived from a living body, specifically blood, cerebrospinal fluid, or the like.

[0029] Although there are no particular limitations on the ultrasonic irradiation unit for atomization, piezoelectric materials are preferred. Piezoelectric materials are widely used in applications such as actuators, ultrasonic wave emitting vibrators, micropower sources, and high-voltage generators. Many of the piezoelectric materials used in these devices are a material known as PZT, which is an oxide containing lead (Pb), zirconium (Zr), and titanium (Ti). Therefore, due to environmental concerns, development of lead-free piezoelectric materials is underway.

[0030] An example of a lead-free piezoelectric material is a Ba-based perovskite oxide expressed by the general formula BaM'O3. Here, M' represents a mixed crystal of one element or two or more elements in a certain composition ratio, but it is necessary to satisfy the requirement that the charge of the general formula BaM'O3 is neutral. An example of a piezoelectric material expressed by BaM'O3 is BaTiO3, which has a tetragonal structure near room temperature.

[0031] A commercially available unit can be used as the ultrasonic irradiation unit. A nebulizer is also a suitable example of a commercially available ultrasonic atomization generator. Another suitable embodiment involves separating the liquid that is the raw material for the fine gas-bubble-containing liquid from a liquid phase provided with a piezoelectric atomization unit that irradiates ultrasonic waves, and then performing indirect piezoelectric atomization. The oscillator frequency is not particularly limited, but 1.6 MHz is preferred.

[0032] Furthermore, as an example of improving acid resistance, alkali resistance, solvent resistance, and corrosion resistance (ozone water, etc.), it is also preferable to coat the liquid-contacting parts of the piezoelectric element with a fluorine-based resin, a titanium-based material, or a glass material such as quartz.

[0033] The following describes humidity. The humidity described herein is relative humidity, with 0% representing an atmosphere in which the target gas component for relative humidity is completely absent within the collection mechanism, and 100% representing an atmosphere in which the target gas component condenses within the collection mechanism. If the target liquid is water, this 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 is started, 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 under power supply. Furthermore, the term "average relative humidity" used herein 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.

[0034] (Explanation of Specific Examples) 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.

[0035] The ozone concentration in the ozone water was quantified using a Pack Test manufactured by Kyoritsu Chemical Research Institute. Furthermore, a nanoparticle size distribution analyzer (model 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 size based on volume of the bubbles contained in the ozone water was used as D50. Similarly, the cumulative 90% particle size was used as D90.

[0036] A Biochecker manufactured by San-ai Oil was used to analyze the smell. To measure the release of ozone into the gas phase, 100 ml of ozone water was placed in a beaker and placed in six 1 cubic meter (1m x 1m x 1m) containers with lids. After one minute, the lids were opened and the smell was smelled. The evaluation criteria are as follows: A: No smell B: I got used to it, but I could still smell it C: There was a clear smell and it irritated my nose and throat D: It made me cough

[0037] Furthermore, using an ozone gas concentration meter, a container with an opening of 10 cm diameter was filled with liquid so that the volume of the container was 50% or more, and while the opening was left open, the ozone gas concentration in the space was measured at room temperature and normal pressure using a gas concentration meter placed 3 cm vertically above the opening. The evaluation criteria for the ozone concentration in the gas at this time are as follows: A: Less than 0.1 B: 0.1 or more but less than 0.2 C: 0.2 or more but less than 0.5 D: 0.5 or more

[0038] The ozone concentration in the liquid was verified. The dissolved ozone concentration in the initial state before production of the FB (Fine Bubble)-containing liquid and after storage of the FB-containing liquid were determined based on a color reaction caused by oxidative coupling with the Trinder reagent. When the upper limit of the measured concentration was reached, the ozone was diluted with ultrapure water and converted into a concentration. The test liquid was sealed in a PFA container without a gas phase and stored at room temperature for 10 days. That is, the ozone concentration at the time of production of the ozone-containing liquid was compared with the ozone concentration 10 days after production. The evaluation criteria for the ozone concentration after 10 days are as follows. When the initial ozone concentration is C0 and the ozone concentration 10 days after production is C10, the change in ozone concentration was calculated using C10 / C0 x 100. A: 80% or more B: 60% or more but less than 80% C: 10% or more but less than 60% D: less than 10%

[0039] The bactericidal effect of ozone water was also verified. Specifically, a comparative test was conducted using a biochecker to compare the effect of ozone water with that of ultrapure water when it was added to a suspension containing Escherichia coli and Staphylococcus aureus. The evaluation criteria are as follows: A: 99% or more B: 80% or more but less than 99% C: 50% or more but less than 80% D: Less than 50%

[0040] Example 1: Ozone water was produced using the device 500 shown in Figure 5. A piezoelectric ceramic microporous mist-maker fogger, commonly used in ultrasonic humidifiers, was used as the atomized bubble generator. This mist-maker fogger was capable of generating approximately 20 ml of 10 μm atomized water per hour. The ambient ozone concentration was measured using an ozone gas detector tube one minute after ozone gas production and was found to be 180 ppm. An ozone generator 102 was installed inside the container. The ambient ozone concentration was measured using an ozone gas detector tube one minute after ozone gas production and was found to be 15 ppm. Ozone water was produced. The average relative humidity (referred to as the average relative humidity) in the collection container during production was 85%. Ozone water was produced using a configuration in which the atomized liquid 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 1.2 ppm. In the following examples, unless otherwise specified, the average relative humidity is 80% or more.

[0041] (Example 2) Using the device 600 shown in Figure 6 (with the atomization bubble generator facing downward), a piezoelectric ceramic microporous mist maker fogger used in ultrasonic humidifiers was used in the same manner as in Example 1. The air ozone concentration was measured using an ozone gas detector tube one minute after ozone gas production and was found to be 15 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 1.2 ppm.

[0042] (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. 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 88%. The ozone concentration in the liquid was 5 ppm.

[0043] (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. 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 5 ppm.

[0044] (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 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.

[0045] (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 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.

[0046] (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 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.

[0047] (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 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.

[0048] (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 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.

[0049] (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 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.

[0050] (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 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.

[0051] (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 ozone gas was produced and was found to be 200 ppm. The 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 99%. The ozone concentration in the liquid was 100 ppm.

[0052] (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 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 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 99%. The ozone concentration in the liquid was 500 ppm.

[0053] Example 14: Ozone water was produced using the device 700 shown in Figure 7. A Seiko Giken piezoelectric atomizing element (1.6 MHz) was used as the atomized bubble generator 101. The atomized bubble generator 101 was placed in a glass container 107, and 300 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 3.5 cm. An ozone generator 102 was installed inside the container. The ambient ozone concentration was measured using an ozone gas detector tube 1 minute after ozone gas production and was found to be 15 ppm. Ozone water was produced. The average relative humidity (mean relative humidity) in the collection container during production was 90%. The ozone concentration in the liquid was 1 ppm.

[0054] (Example 15) Ozone water was produced using the same apparatus as in Example 14. 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 170 ppm. Ozone water was produced. The average relative humidity (referred to as the average relative humidity) in the collection container during production was 90%. The ozone concentration in the liquid was 50 ppm.

[0055] (Example 16) Ozone water was produced using the same apparatus 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 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 99%. The ozone concentration in the liquid was 500 ppm.

[0056] Comparative Example 1 In Example 1 (FIG. 5), an attempt was made to produce ozone water 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% initially, and the average relative humidity during production was 78%. An attempt was made to produce ozone water using this type of device, but collection was difficult.

[0057] Comparative Example 2 In Example 14, 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. Otherwise, ozone water production was attempted in the same manner as in Example 1. Furthermore, the formation of a water column and opacification of the gas phase were not observed at the liquid-gas interface, and no microdroplets were generated.

[0058] Comparative Example 3 In Example 14, the piezoelectric element was changed to a 267 Hz probe type. Otherwise, an attempt was made to produce a fine gas bubble-containing liquid in the same manner as in Example 14. 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.

[0059] Comparative Example 4: Ozone water was produced by injecting high-concentration ozone gas from the outside using an apparatus 800 as shown in Figure 8. An air bubble atomization device 301 was installed, with the air bubble atomization device connected to the exhaust port. Specifically, the gas phase and the aqueous phase were separated by a microporous membrane, the gas phase side was pressurized using an air pump, and air was introduced through the microporous membrane to produce ozone bubbling. A filter membrane (Minimate, manufactured by Nippon Pall) with a molecular weight cutoff of 1,000 was used as the microporous membrane. The ozone concentration in the liquid was 1.5 ppm.

[0060] Comparative Example 5: In the apparatus 900 shown in Fig. 9, ultrapure water was placed in a sealed container, an ozone gas generator was attached, and ozone was generated. The ozone gas generator was then removed, the container was sealed, and the water was stirred with a paint shaker to produce ozone water. The ozone concentration in the liquid was 5 ppm.

[0061] Below, a table summarizing the above examples and comparative examples is provided.

[0062]

[0063]

[0064] The present invention is not limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to apprise the public of the scope of the present invention.

[0065] This application claims priority from Japanese Patent Application No. 2024-017340, filed on February 7, 2024, the contents of which are incorporated herein by reference.

Claims

1. A liquid containing ozone, the liquid containing at least ozone and a plurality of bubbles suspended in the liquid, the D50, which is the cumulative 50% particle size on a volume basis of the particle size distribution of the bubble diameters of the plurality of bubbles contained per unit volume of the liquid, being less than 1 μm, the liquid being placed in a container having an opening with an opening diameter of 10 cm so that the liquid occupies at least 50% of the capacity of the container, the opening being open, and the ozone gas concentration in the space measured at 25°C and 1 atmosphere using a gas concentration meter positioned 3 cm vertically above the opening is less than 0.1 ppm.

2. The liquid according to claim 1, characterized in that the ozone concentration of the liquid containing ozone 10 days after preparation is 60% or more compared to that at the time of preparation.

3. The liquid described in 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 multiple bubbles in the ozone-containing liquid, is less than 1 μm.

4. The liquid according to claim 1 or 2, wherein the ozone concentration of the liquid containing ozone is 5 ppm or more.

5. The liquid according to claim 1 or 2, wherein the ozone concentration of the liquid containing ozone is 13 ppm or more.

6. The liquid according to claim 1 or 2, wherein the ozone concentration of the liquid containing ozone is 50 ppm or more.

7. The liquid according to claim 1 or 2, wherein the ozone concentration of the liquid containing ozone is 70 ppm or more.

8. A method for producing a liquid containing ozone, comprising: a generating step of generating droplets containing fine bubbles by irradiating a liquid with ultrasonic waves to atomize the liquid; a step of contacting the droplets with ozone; a recovery step of recovering the droplets in a recovery container by a recovery mechanism including the recovery container; and a step of obtaining the liquid described in claim 1 or 2 through the recovery step.

9. A method for producing an ozone-containing liquid as described in claim 8, characterized in that the generating step uses a generating device including a mesh and a vibrator, in which liquid is supplied to the mesh and ultrasonic waves are irradiated onto the supplied liquid by the vibrator to generate the bubbles.

10. A method for producing an ozone-containing liquid as described in claim 8, characterized in that the average relative humidity inside the recovery container during the execution of the method for producing an ozone-containing liquid is 80% or more, assuming that the humidity at the time of condensation of the liquid is 100%.

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