Fine bubble ozone treated water manufacturing equipment

Abstract

To provide a fine bubble ozone treated water production apparatus in which a fine bubble ozone treated water that has a small amount of bittern added and whose bactericidal power can be maintained for a long period of time is obtained.SOLUTION: Provided is a fine bubble ozone treated water production apparatus that includes an ozone gas injection unit, a fine bubble generation unit, a storage container, and a piping, and in which the ozone gas injection unit injects ozone gas into an aqueous solution to generate ozone water, and the fine bubble generation unit confines the ozone gas in the ozone water within the generated fine bubbles in the ozone water to yield a fine bubble ozone treated water, and, characterized, in the fine bubble generation unit, at least a part of a region that comes into contact with the fine bubble ozone treated water is formed of synthetic resin.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus for producing fine bubble ozone-treated water in which salts are reduced from fine bubble ozone-treated water containing salts. [Background technology]

[0002] Ozone is an allotrope of oxygen consisting of three oxygen atoms, and has a strong oxidizing effect second only to fluorine. Ozone water has been used as a disinfectant due to its high bactericidal power and the wide range of microorganisms it can kill (Patent Document 1

[0006] , Patent Document 2

[0007] ).

[0003] ~

[0004] , Patent Document 3

[0002] , Patent Document 4

[0002] ). However, it is known that the half-life of dissolved ozone in ozone water is about 20 to 30 minutes, and the sterilizing power is lost in a short period of time (Patent Document 2

[0020] ).

[0003] On the other hand, there is fine bubble technology that can stably trap gas in water. Fine bubbles are generally small bubbles with a diameter of less than 100 μm, and fine bubbles with a diameter of 1 μm or more but less than 100 μm are defined as microbubbles, and those less than 1 μm as ultrafine bubbles. Attempts have been made to extend the half-life of ozone gas, which has a short half-life, by dissolving it in water as fine bubbles (Patent Document 2

[0016] to

[0018] , Patent Document 3

[0002] , Patent Document 4

[0004] ).

[0004] It is also known that the presence of electrolyte ions using common salts contributes to the long-term stability of fine bubble ozone treated water (Patent Document 2

[0019] to

[0020] , Patent Document 3

[0008] ). Furthermore, paragraph

[0052] of Patent Document 5 states, "When the sterilization effect was examined as shown in Figure 4, it was found that, although the number of E. coli bacteria was reduced at an ozone concentration of 14.9 ppm, it was not reduced to the point where its presence was undetectable. In other words, even if ozone water is produced using a solution containing 2% or less bittern and microbubbles as described above, the ozone concentration is low at 14.9 ppm, and the sterilization effect is small (little)." This means that when fine bubble ozone treated water is produced from an aqueous solution containing 2% or less bittern (containing magnesium chloride), the sterilization effect is insufficient. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-21798 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-275089 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-189307 [Patent Document 4] Japanese Patent Application Laid-Open No. 2011-4990 [Patent Document 5] Japanese Patent Application Laid-Open No. 2009-154076 Summary of the Invention [Problem to be solved by the invention]

[0006] It has long been known, as described in Patent Document 5, that the sterilizing power of fine bubble ozone treated water can be maintained for a long period of time by adding a sufficient amount of bittern (4%, for example). However, when fine bubble ozone-treated water containing bittern was sprayed for sterilization, the bittern precipitated as a white precipitate, which was not preferable. For example, fine bubble ozone-treated water is sprayed onto furniture such as tables to disinfect them. After the fine bubble ozone-treated water evaporates, bittern remains on the surface, and even if you try to wipe it off, it cannot be completely removed, leaving behind a residue. After the sterilization process, wiping with water and rinsing are required, which requires a lot of time and effort.

[0007] An object of the present invention is to obtain fine bubble ozone treated water that requires a small amount of bittern added and can maintain its bactericidal power for a long period of time. [Means for solving the problem]

[0008] In order to solve such problems, the present invention has the following configuration. A method for producing fine bubble ozone-treated water, comprising: an ozone water generation step of injecting ozone gas into an aqueous solution to generate ozone water; and a fine bubble generation step of generating fine bubbles in the ozone water and encapsulating the ozone gas within the fine bubbles generated in the ozone water, wherein the aqueous solution is an aqueous solution of magnesium chloride hexahydrate, and the fine bubble generation step comprises: At least a part of the area that comes into contact with the fine bubble ozone treated water is formed from a synthetic resin. Using the fine bubble generator Fine bubble ozone treated water production method method . [Effects of the Invention]

[0009] Fine bubble ozone treated water was obtained that could maintain its bactericidal power for a long period of time and required only a small amount of bittern added. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram of a typical fine bubble ozone treated water production device 1. [Figure 2] FIG. 1 is an explanatory diagram of temperature setting conditions used in an accelerated storage test. [Figure 3] FIG. 1 is a graph showing the bactericidal activity of fine bubble ozone treated water when the amount added was 2.5 g / L in Experiment 1. [Figure 4] FIG. 1 is a graph showing the bactericidal activity of fine bubble ozone treated water when the amount added was 5 g / L in Experiment 1. [Figure 5] FIG. 1 is a graph showing the bactericidal activity of fine bubble ozone treated water when the amount added was 10 g / L in Experiment 1. [Figure 6] FIG. 1 is a graph showing KI values ​​when the amounts added were 2.5 g / L and 5 g / L in Experiment 1. [Figure 7] (a) is the composition of magnesium chloride hexahydrate, and (b) is the composition of bittern manufactured by Nio Kosan Co., Ltd. [Figure 8] FIG. 10 is a graph showing the bactericidal activity of fine bubble ozone treated water when the amount added was 5 g / L in Experiment 2. [Figure 9] FIG. 10 is a graph showing the bactericidal activity of fine bubble ozone treated water when the amount added was 10 g / L in Experiment 2. [Figure 10] FIG. 10 is a graph showing the bactericidal activity of fine bubble ozone treated water after thermal distillation in Experiment 3. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings denote parts with the same functions, and duplicated descriptions in each drawing will be omitted as appropriate. Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] (Example) [Outline of the fine bubble ozone treated water production equipment] There are various types of fine bubble ozone treated water production systems 1, but Figure 1 is an explanatory diagram of a typical fine bubble ozone treated water production system 1. The fine bubble ozone treated water production system 1 in Figure 1 is broadly composed of a storage container 11, an ozone gas injection unit 12, a fine bubble generation unit 13, and piping 17 that connects these units and circulates the air. Of these, the fine bubble generation unit 13 is composed of a fine bubble generating nozzle 131 and a pump 132.

[0013] The aqueous solution is made by adding additives such as bittern and magnesium chloride hexahydrate to filtered tap water.

[0014] One of the raw gases 15 is oxygen gas, which is supplied from an oxygen gas cylinder 151 to an ozonizer 16 and converted into ozone gas. A known ozonizer 16 may be used. 3 The high-concentration ozone gas is sent to the ozone gas injection unit 12 provided in the pipe 17, and is injected into the circulating aqueous solution from the ozone gas injection unit 12 at a flow rate of 0.6 L / min. The aqueous solution is sent by the pump 132 at a circulating water flow rate of 10 L / min.

[0015] On the other hand, the carbon dioxide gas cylinder 152 is used to inject carbon dioxide gas into the aqueous solution. As the carbonate ion content increases, the rate at which ozone decomposition occurs decreases. Carbon dioxide gas is injected into the circulating aqueous solution from the ozone gas injection unit 12 at a flow rate of 0.1 L / min. It is known that the KI value (described below) of ozone water increases when carbon dioxide gas is injected together with ozone gas, but the injection of carbon dioxide gas is not essential; even if only ozone gas is injected, sufficient ozone can be contained by, for example, circulating the aqueous solution through the fine bubble ozone treated water manufacturing device 1 as described below.

[0016] The configuration of the fine bubble generating unit 13 varies depending on the fine bubble generation principle. A pump 132 may or may not be included in the fine bubble generating unit 13. The ozone gas injection unit 12 may be provided in the fine bubble generating nozzle 131. The pressure gauge 14 monitors the pressure of the aqueous solution sent by the pump 132 and entering the fine bubble generating nozzle 131, and adjusts the pressure to be suitable for generating fine bubbles.

[0017] The piping 17 constitutes a circulation flow path, and the piping 17 connects the storage container 11 to the ozone gas injection unit 12. In order to produce a large amount of fine bubble ozone treated water containing a sufficient concentration of fine bubbles, the system is configured to repeat circulation and gradually increase the concentration.

[0018] [Inventor's Attempts and Discoveries] As shown in Figure 4 of Patent Document 5, when fine bubble ozone treated water was prepared using an aqueous solution containing 4% bittern, and the bactericidal power was examined, the initial bactericidal power was 4.2 × 10 5 It is known that the number of E. coli bacteria present in the water drops to zero after one hour. When fine bubble ozone treated water was prepared using an aqueous solution containing 2% bittern, and its sterilizing power was examined, the initial number of bacteria was 4.2 x 10 5 After one hour, the number of E. coli bacteria that had been present had increased to 2.9 x 10 4 The fine bubble ozone treated water with sufficient sterilizing power could not be obtained from the aqueous solution containing 2% bittern.

[0019] Although it would be possible to use fine bubble ozone treated water containing 4% bittern as an aqueous solution for sterilization, there is a problem that when fine bubble ozone water containing bittern is sprayed, bittern remains after evaporation. Therefore, the inventor wondered whether it would be possible to reduce the amount of bittern, although it has been reported that a small amount of bittern does not provide a bactericidal effect.

[0020] First, the inventors produced fine bubble ozone treated water in a laboratory using the above-mentioned fine bubble ozone treated water producing apparatus 1 while varying the amount of bittern. In this experiment, highly pure magnesium chloride hexahydrate was used as an additive instead of bittern, which is produced from seawater and contains salts other than magnesium chloride.

[0021] (Experiment 1) [Manufacturing conditions] Processing capacity: 10L Raw water: Tap water (filtered) Additives: 2.5g / L, 5g / L, 10g / L Ozone gas flow rate: 0.6 L / min Carbon dioxide flow rate: 0.1 L / min Circulating water flow rate: 6.5L / min Pump discharge pressure: 0.4MPa (The filters used are activated carbon filters and hollow fiber membrane filters.)

[0022] The fine bubble ozone-treated water after production was filled into a PET bottle and stored under accelerated conditions. 23 weeks after production (equivalent to 138 weeks in the accelerated test), the test bacteria (Geobacillus stearothermophilus (ATCC 9372)) was treated with a 5-fold dilution of the fine bubble ozone-treated water, and the number of bacteria was measured after 3, 5, and 10 minutes.

[0023] <Storage acceleration conditions> To verify the shelf life over a period of several months to a year, an accelerated storage test was conducted to virtually predict the change in bactericidal activity during long-term storage. The accelerated storage test is as follows. The temperature during storage was adjusted as follows, and one cycle of (1) to (5) (240 minutes; Figure 2) was used for one day. After a certain number of cycles had elapsed, the stored fine bubble ozone-treated water was taken out and its bactericidal power was tested. (1) Raise the temperature from room temperature (20°C) to 30°C (2) Keep at 30°C for 2 hours (3) Lower the temperature from 30°C to 10°C (4) Keep at 10°C for 2 hours (5) Raise the temperature from 10°C to 30°C

[0024] Surprisingly, in Experiment 1, even though the additives were used at small amounts of 2.5 g / L, 5 g / L, and 10 g / L, the number of test bacteria was reduced to 4.9 × 10 4 Three minutes later, the number of bacteria had dropped from 0 to 0, indicating that the bacteria had been sufficiently sterilized.

[0025] Therefore, the inventors investigated what factors contributed to the fact that the bactericidal activity of fine bubble ozone treated water was maintained for a long period of time at an added amount that was previously thought to be unable to maintain bactericidal activity.

[0026] [Factor 1] First, regarding the fine bubble ozone treated water production equipment 1, the laboratory fine bubble ozone treated water production equipment 1 was made of resin because the production volume was small, while the industrial fine bubble ozone treated water production equipment 1 for mass production was made of stainless steel, which was a difference.

[0027] Around the fine bubble generating nozzle 131 of the fine bubble ozone treated water manufacturing apparatus 1, the flow of ozone water changes drastically, which places a large load on the materials around the fine bubble generating nozzle 131, as will be described in detail below. When the ozone water flows into the fine bubble generating nozzle 131 and passes through the orifice, the pressure rises suddenly. Then, when the water leaves the orifice, the pressure drops suddenly, causing the dissolved gas (ozone gas) to be generated as fine bubbles. The principle of fine bubble generation is that the pressure of the ozone water is increased for a very short time, dissolving the ozone gas into the aqueous solution. Then, the pressure in the flow of ozone water suddenly drops below the saturated vapor pressure, generating small bubbles. A large number of small bubbles containing ozone gas are generated around tiny "bubble nuclei" of 100 μm or less that exist in the ozone water.

[0028] Turbulence occurs at the outlet of the orifice in the fine bubble generating nozzle 131, causing significant pressure fluctuations. The turbulence can occasionally create an area where the surrounding pressure is higher than the saturated vapor pressure. When bubbles enter this area, the ozone gas in the bubbles suddenly dissolves into the ozone water, causing the surrounding ozone water to rush toward the center of the bubbles. At this time, a small but strong pressure wave is generated. This is a phenomenon called cavitation. If this cavitation occurs repeatedly near the walls that make up the fine bubble generating nozzle 131 or the piping 17, the surface will gradually fatigue, even if the wall material is a metal such as stainless steel, and eventually the hard surface will erode and be gouged away.

[0029] The fine bubble generating nozzle 131 is also used to produce fine bubbles containing gases other than ozone, and there is no dedicated fine bubble generating nozzle 131 that is particularly suitable for ozone. The inventors considered that ozone, due to its strong oxidizing power, induces erosion that does not occur with ordinary gases.

[0030] Furthermore, it is possible that tiny impurities made of metals produced by erosion act like a catalyst, decomposing the ozone contained in the fine bubble ozone treated water even in small amounts, thereby robbing the water of its bactericidal power. It is also possible that electrolytes, which are salts such as magnesium chloride that are added to stabilize ozone over the long term, are consumed by tiny impurities, causing the decomposition of ozone.

[0031] In contrast, in the fine bubble ozone treated water production system 1 used in the experiment, most of the parts that come into contact with the aqueous solution are made of polytetrafluoroethylene (PTFE). PTFE is relatively stable against ozone, and it is thought that the phenomenon of reducing ozone in the aqueous solution described above, which occurs in stainless steel fine bubble ozone treated water production systems, does not occur, or is unlikely to occur.

[0032] The inventors then concluded that the fact that most of the components of the fine bubble ozone treated water production device 1 (components other than the pump 132) are made of this PTFE is the reason why the fine bubble ozone treated water retained its bactericidal power for a long period of time, even though it was produced with the smallest amount of additive, 2.5 g / L, as shown in the experimental results.

[0033] From the above, it was found that when at least the part of the fine bubble ozone treated water production device that comes into contact with the fine bubble ozone treated water is made of PTFE, the bactericidal power of the fine bubble ozone treated water can be maintained for a long period of time.

[0034] [Modification of fine bubble ozone treated water production device] (1) Since cavitation occurs downstream of the fine bubble generating nozzle 131, it is thought that a similar effect can be obtained simply by forming the fine bubble generating nozzle 131 and the downstream piping 17 from PTFE. (2) Similar effects are expected to be obtained with materials that are relatively stable against ozone, such as fluororesins like PTFE and synthetic resins like polyvinyl chloride resin. (3) In the fine bubble ozone treated water manufacturing device 1, it is sufficient that the surface that comes into contact with the fine bubble ozone treated water is made of a material that is relatively stable against ozone. Therefore, it is considered that the same effect can be obtained by coating only the surface of the stainless steel component that comes into contact with the fine bubble ozone treated water with a material that is relatively stable against ozone.

[0035] Since the bactericidal power depends on the amount of ozone in the fine bubble ozone treated water, this was confirmed by measuring the KI value (described below). Fine bubble ozone treated water produced with additive amounts of 2.5g / L and 5g / L was stored at room temperature, and the KI values ​​were measured every week (7 days). The results are shown in Figure 6. In the figure, the solid line represents the case where the additive amount was 5g / L, and the dotted line represents the case where the additive amount was 2.5g / L. In both cases, the KI value dropped sharply immediately after production, but stabilized within about a week and then tended to gradually decrease.

[0036] (KI value) The KI value refers to the measured value of ozone concentration obtained by measurement using the KI method. That is, the KI method is a measurement method that utilizes the release of I2 from KI (potassium iodide) in the presence of an oxidizing agent. The KI method is a commonly used method for measuring ozone concentration.

[0037] [Factor 2] Another difference in this experiment was that high-purity magnesium chloride hexahydrate was used as the additive, rather than bittern. Therefore, in Experiment 2 below, an experiment was conducted using bittern (Nio Industries Co., Ltd. bittern) as an additive. (The ingredients of magnesium chloride hexahydrate and Nio Industries Co., Ltd. bittern are shown in Figure 7.) (Experiment 2) [Manufacturing conditions] Processing capacity: 10L Raw water: Tap water (filtered) Additives: 5g / L, 10g / L Ozone gas flow rate: 0.6 L / min Carbon dioxide flow rate: 0.1 L / min Circulating water flow rate: 6.5L / min Pump discharge pressure: 0.4MPa (The filters used are activated carbon filters and hollow fiber membrane filters.)

[0038] The results of Experiment 2 are shown in Figures 8 and 9. As shown in Figures 4 and 5, magnesium chloride hexahydrate sufficiently killed the bacteria, reducing the number to 0 after 3 minutes of treatment. In contrast, as shown in Figures 8 and 9, the bittern manufactured by Nio Industries Co., Ltd. had a bacterial count of 1.6 x 10 even after 10 minutes of treatment. 2 pieces, 1.4×10 2 Some bacteria remained and sufficient sterilization was not achieved.

[0039] This suggests that salts other than magnesium chloride contained in bittern have some effect on the ozone in the fine bubble ozone treated water, decomposing the ozone and reducing the ozone concentration.

[0040] From the above, it was found that the bactericidal activity of fine bubble ozone treated water can be maintained for a long period of time by using magnesium chloride hexahydrate as an additive when producing fine bubble ozone treated water.

[0041] As mentioned above, it was found that by using a resin fine bubble ozone treated water production device and by using magnesium chloride hexahydrate as an additive, the bactericidal power can be maintained for a long period of time even if the amount added is reduced.

[0042] However, the inventors wondered whether it would be possible to further reduce the amount of magnesium chloride in fine bubble ozone treated water. Because there is a limit to how much magnesium chloride can be reduced during production, they came up with the idea of ​​removing magnesium chloride from the fine bubble ozone treated water after production.

[0043] Various known purification methods can be considered for removing magnesium chloride from fine bubble ozone treated water. Therefore, among various purification methods, the inventors attempted to purify fine bubble ozone-treated water containing magnesium chloride by heating and distilling it to remove magnesium chloride from the fine bubble ozone-treated water.By heating and distilling the water, they were able to obtain purified fine bubble ozone-treated water with a significantly reduced magnesium chloride concentration.

[0044] The heating distillation apparatus is a commonly used device in which unpurified fine bubble ozone treated water is placed in an evaporator made of a glass container or the like, heated to evaporate, and the resulting vapor is condensed in a condenser and collected in a collection container made of a glass container or the like.

[0045] (Experiment 3) [Manufacturing conditions] Processing capacity: 10L Raw water: Tap water (filtered) Additive: 2.5g / L Ozone gas flow rate: 0.6 L / min Carbon dioxide flow rate: 0.1 L / min Circulating water flow rate: 6.5L / min Pump discharge pressure: 0.4MPa (The filters used are activated carbon filters and hollow fiber membrane filters.)

[0046] As in Experiment 1, fine bubble ozone-treated water was produced by adding 2.5 g / L of magnesium chloride hexahydrate. After production, the water was filled into PET bottles and subjected to heat distillation 12 weeks (equivalent to 72 weeks) after production in an accelerated storage test. Nine weeks (equivalent to 54 weeks) after heat distillation, the test bacteria (Geobacillus stearothermophilus (ATCC 9372)) was treated with a 5-fold dilution of the fine bubble ozone-treated water, and the number of bacteria was measured after 3, 5, and 10 minutes.

[0047] The results of Experiment 3 are shown in Figure 10, and it was found that the fine bubble ozone treated water after heat distillation still retained sufficient bactericidal power.

[0048] As described above, fine bubble ozone treated water retains sufficient bactericidal power even after thermal distillation, and it was found that thermal distillation can further reduce the magnesium chloride content while maintaining bactericidal power.

[0049] The fine bubble ozone treated water produced by thermal distillation contains almost no magnesium chloride, so even when sprayed for sterilization, bittern does not precipitate after the fine bubble ozone treated water evaporates, making sterilization easy.

[0050] In Experiment 3, thermal distillation was used as the purification method, but other purification methods, such as a purification method using an ion exchange membrane, can also be applied, and it is believed that the same effects as purification by thermal distillation can be obtained.

[0051] The embodiments of the present invention have been described above in detail with reference to the drawings, but the specific configurations are not limited to these embodiments, and the present invention also includes design changes and the like within the scope of the present invention that do not deviate from the gist of the present invention. Furthermore, the above-described embodiments can be combined by utilizing the techniques of each other, as long as there are no particular contradictions or problems in the purpose, configuration, etc., of the embodiments. [Explanation of symbols]

[0052] 1 Fine bubble ozone treated water production equipment 11 Storage container 12 Ozone gas injection section 13 Fine bubble generator 131 Fine bubble generating nozzle 132 Pump 14 Pressure gauge 15 Raw material gas 151 Oxygen gas cylinder 152 Carbon dioxide cylinder 16 Ozonizer 17 Piping

Claims

1. A method for producing fine bubble ozone treated water, comprising: an ozone water generating step of injecting ozone gas into an aqueous solution to generate ozone water; A fine bubble generating step of generating fine bubbles in the ozone water and encapsulating the ozone gas in the fine bubbles generated in the ozone water is included. the aqueous solution is an aqueous solution of magnesium chloride hexahydrate, The fine bubble ozone treated water manufacturing method is characterized in that the fine bubble generating step uses a fine bubble generating unit in which at least a part of the area in contact with the fine bubble ozone treated water is formed of synthetic resin.

2. The fine bubble generating unit is provided with a fine bubble generating nozzle, 2. The method for producing fine bubble ozone treated water according to claim 1, wherein the area of ​​the fine bubble generating nozzle that comes into contact with the fine bubble ozone treated water is made of synthetic resin.

3. A method for producing fine bubble ozone-treated water as described in claim 1 or 2, characterized in that the entire fine bubble generating unit, including the area that comes into contact with the fine bubble ozone-treated water, is formed from synthetic resin.

4. A method for producing fine bubble ozone-treated water as described in claim 1 or 2, characterized in that the fine bubble generating unit has an area that comes into contact with the fine bubble ozone-treated water coated with synthetic resin.

5. The method for producing fine bubble ozone treated water according to any one of claims 1 to 4, characterized in that the synthetic resin is a fluorine-based resin or a polyvinyl chloride resin.

6. A method for producing fine bubble ozone-treated water described in any one of claims 1 to 5, characterized in that in the ozone water generation process, carbon dioxide gas is injected together with the ozone gas.

7. A method for purifying fine bubble ozone-treated water, comprising the step of purifying the fine bubble ozone-treated water produced by the method for producing fine bubble ozone-treated water according to any one of claims 1 to 6.

8. The method for purifying fine bubble ozone-treated water according to claim 7, wherein the purification step is a step using thermal distillation.

9. A method for purifying fine bubble ozone-treated water as described in Claim 7, characterized in that the purification process is a process using an ion exchange membrane.

Images