JPH0639256A - Method and device for dissolving ozone - Google Patents

Abstract

PURPOSE:To dissolve ozone in raw water without contaminating the raw water by bringing ozone contg. gas into contact with dissolving water through though- holes through which gas passes but liquid does not pass and sucking ozone in ozone contg. gas into a thin tube to dissolve it in the dissolving water. CONSTITUTION:Dissolving water is caused to flow in thin tubes 12 having a lot of through holes 11 through which gas passes but liquid does not pass from a dissolving water feed port 9 and ozone contg. gas is fed to around the thin tubes 12 from an ozone contg. water feed port 13. Then the ozone contg. gas comes into contact with the dissolving water through the through-holes 11 to dissolve ozone in the dissolving water. As a result, ozone in ozone contg. gas is effectively dissolved in raw water for producing high purity water without contaminating the raw water or ozone in ozone contg. water is effectively dissolved in water to be treated that is to be sterilized without contaminating the water to be treated to directly treat the water to be treated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing ozone water and treating water to be treated, and more particularly, suitable for producing high-purity pure water used for semiconductor production, biotechnology and the like. High-purity ozone water is produced by dissolving ozone-containing gas in raw water, or sterilization of the water to be treated is performed by directly dissolving the ozone-containing gas in the water to be treated to be sterilized. Method and apparatus for

[0002]

[Prior Art and its Problems] The purity of high-purity pure water (so-called ultrapure water) used for semiconductor manufacturing, biotechnology, etc. has been improved by ion-exchange resin treatment or advanced distillation technology in recent years. It has become extremely high, and its electric conductivity is approaching 18.24 MS / cm, and it is approaching a state in which almost no free ions are present. However, such high-grade pure water also contains dead bodies of microorganisms such as bacteria and nonionic substances that cannot be removed by the ion exchange method or the distillation method, and prevents further improvement in purity. The limit on the amount of impurities that can be contained in ultrapure water is gradually becoming stricter, and it is currently required to reduce the number of particles of 0.07 μm or more to less than 10. On the other hand, ozone is attracting attention as a strong and clean oxidant, and its decomposition product is oxygen, and the residue does not remain in the water to be treated compared to that of chlorine-based oxidizers that have been used conventionally. The use for water treatment is increasing because the decomposition rate is high and ozone itself does not remain and there is no problem of secondary pollution. In order to improve the purity of the ultrapure water, it is desirable to adopt an ozone treatment method together with an ion exchange method and a distillation method. In order to improve the purity of ultrapure water produced by ozone treatment, it is necessary to prevent contamination due to ozone dissolution during ozone treatment.

In order to generate ozone useful as an oxidant, the discharge method and the electrolysis method have been mainly used in the past, but the electrolysis method is now the mainstream because of the purity of the product and the ease of operation. ing. To perform water treatment using ozone generated by this electrolysis method, ozone water obtained in a gas-liquid mixed state is brought into direct contact with the water to be treated, or the water to be treated is sent directly to the anode chamber of the electrolytic cell. However, in the former case, since ozone exists in the form of bubbles in the former case, the contact efficiency with the water to be treated is poor and the electrode water is mixed with the ozone water generated in the electrolytic cell, and the substance is treated with water. However, in the latter case, there is a problem that the electrodes are contaminated by impurities in the water to be treated. Therefore, in many cases, ozone generated in the anode chamber of the electrolytic cell in a gas-liquid mixed state is once supplied to the mixing tank through, for example, a filter, impurities are removed by the filter, and ozone in the gas-liquid mixed state is mixed by the filter. The ozone water is dispersed in the tank and the ozone is almost completely dissolved in the water in the mixing tank to generate a uniform concentration of ozone water containing no gaseous ozone, and the treated water is treated by the ozone water. .

The higher the concentration of such ozone water, the higher the efficiency of treatment of the water to be treated, the more effective use of ozone generated by electrolysis and the treatment of the water to be treated are preferable, but the ozone gas itself is preferable. Solubility in water is small, and it cannot be said that ozone is sufficiently dispersed when a filter or the like is used. Further, it is unavoidable that impurities of ozone gas contaminate pure water. Therefore, in particular, there is a demand for a novel method for easily producing high-purity ozone water for producing the ultrapure water whose purity is further increased. Further, the ozone-containing gas may be directly dissolved in the water to be treated to be sterilized to treat the treated water, and in this case as well, the treatment efficiency such as sterilization depends on the ozone solubility in the treated water. There is a strong demand for means for improving the dissolution efficiency of ozone-containing gas even in the case of treating water to be treated by directly treating ozone-containing gas.

[0005]

It is an object of the present invention to dissolve ozone in an ozone-containing gas in raw water for producing high-purity water efficiently without contaminating the raw water, or to treat water in the ozone-containing gas to be sterilized. An object of the present invention is to provide a method and a device for directly treating water to be treated by efficiently dissolving ozone without polluting the water to be treated.

[0006]

According to the method of the present invention, the water to be dissolved is circulated in a thin tube having a large number of through holes which are permeable to gas and impermeable to liquid, and an ozone-containing gas is supplied around the narrow tube. A method of dissolving ozone, wherein the ozone-containing gas is brought into contact with the water to be dissolved through the through hole to dissolve the ozone in the water to be dissolved, wherein the device of the present invention is a tubular body, A plurality of capillaries made of a hydrophobic substance having a large number of through holes, which are installed in the main body, through which water to be dissolved flows, and which allow gas to pass and liquid to pass, and a means for supplying an ozone-containing gas into the main body It is an ozone dissolution apparatus characterized by comprising and.

The present invention will be described in detail below. The present invention is
Dissolving ozone in the ozone-containing gas into the water to be dissolved by contacting the ozone-containing gas with the water to be dissolved through a through hole that is gas permeable and liquid impermeable to enhance ozone dissolution efficiency in the water to be dissolved Is characterized by. When ozone-containing gas is supplied to the periphery of the thin tube in a state where the water to be dissolved in which ozone is to be dissolved is flowing in the thin tube in which a large number of the through holes are formed, the thin tube is formed due to the ejector effect by the flow of the water to be dissolved. The ozone-containing gas outside the through hole is sucked into the thin tube through the through hole and comes into contact with and dissolves in the water to be dissolved. At this time, if the diameter of the through hole is set to a diameter that allows gas to pass therethrough and does not allow liquid to pass therethrough, that is, about 0.1 to 10 μm, for example, lead dioxide, etc., which may be contained in the electrolytically produced gas produced by the electrolysis method, etc. Even if the electrode substances and impurities of the above exist in the ozone-containing gas, these substances dissolve in the liquid as ions or exist as mist, and therefore penetrate or penetrate into the water to be dissolved through the through holes. There is nothing to do.

The water to be dissolved in the present invention means raw water of high-purity ozone water suitable for producing high-purity pure water used for semiconductor manufacturing, biotechnology, etc., or direct sterilization by contact with ozone. Water to be treated, etc. is included. Further, the ozone-containing gas of the present invention is a generic term for gases containing ozone produced by an electrolysis method, a discharge method, or the like,
In many cases, the ozone-containing gas contains ozone and oxygen. The thin tube having a large number of through holes is preferably formed of a hydrophobic substance such as a fluororesin. For example, a nonwoven fabric of a fluororesin is fired with a small amount of a calcium compound to form a tube, and then acid treatment or heat treatment is performed. A large number of through holes can be formed in the peripheral surface of the capillary by eluting or decomposing the calcium compound. The inner diameter of the thin tube is not particularly limited, but is preferably less than 6 mm in order to efficiently bring the water to be dissolved flowing therein into contact with the ozone-containing gas.

The tubular body for accommodating the thin tube is preferably made of a corrosion-resistant substance such as quartz glass, fluororesin, titanium or titanium-based alloy, and the inside of the body is hermetically sealed so that outside air or the like enters. It is preferable to have a structure that does not. An ozone-containing gas supply port and an ozone-containing gas outlet are formed in the main body, an ozone-containing gas generated by an electrolysis method or the like is supplied into the main body from the supply port, and is supplied into the main body through the through hole. The ozone-containing gas containing ozone other than that dissolved in the water to be dissolved is taken out from the outlet. The ozone-containing gas taken out may be supplied again into the main body through the ozone-containing gas supply port, if necessary. When the pressure of the ozone-containing gas supplied into the main body is made higher than the pressure of the water to be dissolved flowing in the thin tube, the dissolution is further promoted, but even if the pressure of the ozone-containing gas is normal pressure, the ejector described above is used. Ozone dissolution proceeds due to the effect. According to the present invention, when the water to be dissolved and the ozone-containing gas are brought into contact with each other, the efficiency of dissolving ozone in the water to be dissolved (the ratio of dissolved ozone to the supplied ozone) reaches about 80%, which is an unprecedented dissolution efficiency and contamination with impurities Without this, high-concentration ozone water can be generated, or ozone treatment of the water to be treated can be sufficiently performed.

Next, one example of the ozone dissolving apparatus according to the present invention will be explained based on the attached drawings, but the apparatus usable for carrying out the apparatus of the present invention and the method of the present invention is not limited to the ozone dissolving apparatus. FIG. 1 is a vertical sectional view showing an example of an ozone dissolving apparatus according to the present invention. An upper connection in which a plurality of fitting holes 4 are substantially evenly distributed and formed in the upper surface of the upper flange 1 and the lower surface of the lower flange 2 of a cylindrical body 3 having upper and lower flanges 1 and 2, respectively. Board 5
And the lower connecting plate 6 are in contact with each other so that their peripheries are aligned. On the upper connecting plate 5, a downward bowl-shaped lid 8 having a water-dissolved water outlet 7 formed at the center of the upper portion is in contact with each other so that their peripheral edges are aligned, and the upper flange 1, the upper connecting plate 5, and The lid body 8 is clamped by a clamp or the like and maintained in a sealed state. Similarly, on the lower surface of the lower connecting plate 6, an upward bowl-shaped bottom body 10 in which a water-to-be-dissolved supply port 9 is formed at the center of the lower portion is contacted so that the respective peripheral edges are aligned,
The lower flange 2, the lower connecting plate 6 and the bottom body 10 are clamped by a clamp or the like and maintained in a sealed state.

A large number of through holes 11 are formed in the corresponding fitting holes 4 formed in the upper connecting plate 5 and the lower connecting plate 6, and both ends of the thin tubes 12 installed substantially parallel to each other are fitted. And an ozone-containing gas supply port on the lower left side surface of the main body 3
13 is also the ozone-containing gas outlet on the upper right side of the main body 3.
14 are formed respectively. When water to be dissolved such as pure water is supplied from the water to be dissolved supply port 9 of the ozone dissolution apparatus configured as described above and ozone-containing gas such as a mixed gas of oxygen and ozone is supplied from the ozone-containing gas supply port 13 respectively. The water to be dissolved flows upward in the plurality of thin tubes 12, and the ozone-containing gas comes into contact with the thin tubes 12. The ozone-containing gas in contact with the thin tube 12 comes into contact with the water to be dissolved flowing in the thin tube 12 through the through hole 11 and is sucked into the thin tube 12 by the ejector effect of the water to be dissolved to be dissolved in the water to be dissolved, so that the high concentration Ozone water is generated or the water to be dissolved (water to be treated) itself is sterilized. The ozone-containing gas containing undissolved ozone is taken out from the ozone-containing gas outlet 14, and the generated high-concentration ozone water or the water to be treated which has been sterilized is taken out from the dissolved water outlet 7.

[0012]

EXAMPLES Next, examples of production of highly concentrated ozone water and treatment of water to be treated by the method of the present invention will be described, but the examples do not limit the present invention. Example 1 Ozone water was produced using the apparatus shown in FIG. The main body was made of quartz glass and had a cylindrical shape with a length of 100 cm and an inner diameter of 6.5 cm, and a pair of connecting plates having an inner diameter of 2 mm and having 60 fitting holes formed therein were brought into contact with the upper and lower flanges.

A mixture of a fibrous fluororesin having a fiber diameter of 0.1 to 5 μm and a length of 1 to 10 cm and powdery calcium carbonate is kneaded and fired at 200 to 450 ° C., and an inner diameter of 2 mm and a length of 120 cm.
After being molded into a thin tube, the calcium carbonate was removed by acid treatment to form a through hole having a pore diameter of 2 to 5 μm in the thin tube.
The thin tube was fitted in the fitting holes of the pair of connecting plates, and the lid and the bottom were arranged to complete the ozone dissolving apparatus. An ozone-containing gas composed of 85% by weight of oxygen and 15% by weight of ozone produced by an electrolysis method was supplied from the ozone-containing gas supply port of the ozone dissolving apparatus at a rate of 0.2 g / liter, and pure water was supplied to the dissolved water supply port. Was supplied at a rate of 1 liter / min. The ozone concentration of pure water taken out from the dissolved water outlet is 160
mg / liter, and the ozone dissolution efficiency (dissolved ozone /
The supplied ozone) was 80%.

Example 2 Using the same apparatus as in Example 1, 1 particle of ultrapure water of 4 particles (0.07 μm) / milliliter was supplied from the supply port for water to be dissolved.
It was supplied at a rate of 1 liter / minute, and the same ozone-containing gas as in Example 1 was supplied at a rate of 0.02 liter / minute. The number of particles in the water to be dissolved (ultra pure water) taken out from the water to be dissolved outlet (ultra pure water) was 4 particles / ml, which was unchanged, and the number of particles through the narrow tube and metal elution did not occur.

Comparative Example 1 A container having a volume of 1 liter was filled with the same ultrapure water as in Example 2 and the ozone-containing gas used in Example 1 was stirred at 0.02.
Publized at a rate of 1 liter / minute for 30 minutes. The ozone concentration of the obtained ozone water was 100 mg / liter, the ozone dissolution efficiency (dissolved ozone / supply ozone) was 80%, and the number of particles was 1000 particles / milliliter. Example 2
Comparing Comparative Example 1 with Comparative Example 1, while ozone gas can be dissolved by bubbling ozone gas into ultrapure water in Comparative Example 1,
In contrast to ultrapure water being contaminated by the increase in the number of particles as impurities, in Example 2, the number of particles before and after the ozone dissolution treatment did not increase or decrease, and the ozone dissolution treatment was performed without causing contamination by impurities. You can see that

Example 3 Using the same apparatus as in Example 1, water to be treated containing 10 bacteria / ml of bacteria was supplied at a rate of 1 liter / minute from the water to be dissolved supply port, and the same as in Example 1. Ozone-containing gas was supplied at a rate of 0.02 l / min. The number of bacteria in the water to be treated taken out from the dissolved water outlet is 0
The number was reduced to pieces / milliliter.

[0017]

According to the method of the present invention, the water to be dissolved is circulated in a thin tube having a large number of through holes which are permeable to gas and impermeable to liquid, and an ozone-containing gas is supplied to the periphery of the thin tube, and the ozone-containing gas is supplied. Is a method of contacting the water to be dissolved through the through hole to dissolve ozone in the water to be dissolved. According to the method of the present invention, the ozone-containing gas is brought into contact with the water to be dissolved flowing in the narrow tube through the through hole, and the ozone-containing gas is sucked from the through hole due to the ejector effect of the water to be dissolved flowing through the hole to be dissolved. Highly concentrated ozone water is generated by being dissolved in water, or the water to be dissolved itself is sterilized. The dissolution efficiency of the method of the present invention is higher than the bubbling method and the method of dispersing and dissolving with a filter which are used for conventional ozone dissolution, and it is possible to efficiently generate high-concentration ozone water or to treat water to be treated. Become. Since the method of the present invention dissolves ozone through the micropores, increase in the number of particles of water to be dissolved, dissolution of metal, etc. can be prevented, and it can be suitably used for production of ultrapure water.

The apparatus of the present invention comprises a plurality of hydrophobic substances each having a cylindrical main body and a large number of through-holes provided in the main body, through which water to be dissolved flows, gas permeates and liquids does not permeate. An apparatus comprising a thin tube and means for supplying an ozone-containing gas into the main body. According to the device of the present invention, as in the method of the present invention, the ozone-containing gas is sucked from the through hole by the ejector effect of the water to be dissolved flowing through the narrow tube and dissolved in the water to be dissolved to generate high-concentration ozone water, or Since the water to be dissolved itself is sterilized, it is possible to achieve higher dissolution efficiency than the bubbling method or the filter dissolution method. Further, in the device of the present invention, since the thin tube is made of a hydrophobic substance such as a fluororesin, the water to be dissolved in the thin tube is reliably prevented from penetrating outside the thin tube, and ozone can be smoothly dissolved. The diameter of the through hole of the thin tube of the device of the present invention is 0.1 to 10 μm.
In this range, the function of the through hole is achieved in which only the ozone-containing gas is allowed to pass and the invasion of impurities and the contamination are prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example of an ozone dissolving apparatus according to the present invention.

[Explanation of symbols]

3 ... Main body 7 ... Dissolved water outlet 9 ... Dissolved water supply port 11 ... Through hole 12 ... Capillary tube 13 ... Ozone-containing gas supply port 14 ... Ozone-containing gas Outlet

Claims (5)

[Claims] 1. A melted water is circulated in a thin tube having a large number of through holes that allow gas to pass therethrough and does not allow liquid to pass therethrough, and an ozone-containing gas is supplied to the periphery of the thin tube, and the ozone-containing gas is supplied to the melted water. A method for dissolving ozone, characterized in that ozone is dissolved in the water to be dissolved by bringing the ozone into contact with the water through the through hole. 2. The method according to claim 1, wherein the pressure of the ozone-containing gas is set higher than the pressure of the water to be dissolved flowing in the narrow tube. 3. A tubular main body, a plurality of thin tubes made of a hydrophobic substance having a large number of through-holes provided in the main body, through which water to be dissolved flows, gas permeation and liquid permeation, and An ozone dissolution apparatus comprising: a means for supplying an ozone-containing gas into the main body. 4. The device according to claim 3, wherein the diameter of the through hole is 0.1 to 10 μm. 5. The device according to claim 3, wherein the thin tube is made of a fluororesin.