JP3040549B2 - High purity water production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing high-purity water using both an ion exchange resin and an electrochemical treatment. More specifically, the present invention relates to a method for producing a deionized water by first conducting an electrochemical treatment of raw water. The present invention relates to a method for preventing contamination of an ion exchange resin to be used by treating it with an ion exchange resin after the treatment, and further improving the purity of the high-purity water obtained.

[0002]

2. Description of the Related Art Conventionally, high-purity water purified by distillation, sterilization, deionization, or the like has been used for various purposes such as semiconductor manufacturing, academic experiments, and cleaning of precision instruments. In order to produce such high-purity water by deionization, for example, by supplying raw water to an ion-exchange tower filled with an ion-exchange resin and adsorbing impurity ions to the ion-exchange resin, the purity of the raw water is improved. Being manufactured. However, according to this method, the ion exchange resin is contaminated by organic substances, suspended solids, microorganisms and the like present in the raw water, and the exchange of the ion exchange resin must be performed in a relatively short period of time. In order to recover the contamination of the ion-exchange resin, regenerative treatment with various chemicals is also performed. However, the cost increases, and furthermore, there is a problem of environmental pollution due to disposal of the used chemicals. There is a demand for the development of a technique for preventing contamination of the exchange resin.

[0003]

Problems to be Solved by the Invention Organic substances and suspended solids in raw water are the most prominent factors contributing to contamination of ion exchange resins. In order to remove organic substances and suspended substances in the raw water, the raw water is removed. It has been widely practiced to prevent the ion exchange resin from being contaminated by filtering it with various filters before supplying it to the ion exchange tower and then contacting the ion exchange resin with the ion exchange resin. However, impurities contaminating the ion exchange resin include not only solids that can be removed by filtration but also fine impurities that pass through the filter like microorganisms. Therefore, in order to prevent the ion exchange resin from being contaminated, it is not sufficient to use a filtration operation alone, and a more effective treatment method is desired.

[0004]

An object of the present invention is to minimize the contamination of the ion exchange resin by using an electrochemical treatment together with the production of high-purity deionized water using the ion exchange resin. It is an object of the present invention to provide a method for stably producing the deionized water over a long period of time by reducing the frequency of ion exchange resin exchange and the frequency of regenerative treatment.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method for producing high-purity water by contacting raw water containing impurities with an ion-exchange resin .
Anode potential is +0.2 to +1.2 V (vs. SCE), cathode potential is 0
To a fixed bed type three-dimensional electrode electrolytic cell to which a voltage is applied so as to have a voltage of about -1.0 V (vs. SCE), electrochemically treating the raw water, and then contacting the ion exchange resin. And producing a high-purity water. Although the bath used in the present invention for not causing substantial electrochemical reaction on the surface of the electrodes, etc. In the present invention method should say electrochemical treatment bath, it referred to as electrolytic cells according to the general designation.

Hereinafter, the present invention will be described in detail. The method of the present invention not only prevents the contamination of the ion exchange resin as described above, but also reduces the hardness components such as calcium ions and magnesium ions in the raw water by treating the raw water in the fixed-bed type three-dimensional electrode electrolytic cell. It is characterized in that the ion load of the ion exchange resin can be reduced. In the present invention, before the raw water is supplied to an ion exchange tower or the like filled with an ion exchange resin, the raw water is supplied to a fixed-bed type three-dimensional electrode electrolytic cell to perform an electrochemical treatment. An electrode electrolytic cell having the following configuration is used. The electrolytic cell is a fixed-bed type three-dimensional electrode electrolytic cell, that is, a fixed-bed monopolar electrolytic cell and a fixed-bed bipolar electrode electrolytic cell. In these electrolytic cells, the three-dimensional electrode of the electrolytic cell has an enormous surface area. Is advantageous in that the contact area between the electrode surface and the raw water can be increased, whereby the size of the device can be reduced and the efficiency of the electrochemical treatment can be increased.

The electrodes in the fixed-bed type three-dimensional electrode electrolytic cell generally include a three-dimensional electrode and a power supply electrode, and the three-dimensional electrode has a shape corresponding to the above-described electrolytic cell to be used. When using an electrolytic cell, a porous material that is permeable to the raw water, for example, activated carbon, graphite, carbon fiber or other carbon having a shape such as granular, spherical, felt, woven or porous block. A plurality of, preferably granular, spherical, or fibrous formed from metallic materials such as nickel, copper, stainless steel, iron, and titanium having the same shape, and a material obtained by coating the metallic material with a noble metal. , Felt, woven, porous block,
A sponge-like dielectric is placed in a DC electric field, and a DC voltage or an AC voltage is applied between power supply electrodes formed of a porous plate such as a flat plate or an expanded mesh or a perforated plate provided at both ends to apply the dielectric. It is possible to use a fixed-bed type bipolar electrolytic cell containing a three-dimensional electrode formed by polarizing the body and forming an anode and a cathode at one end and the other end of the dielectric, respectively. Or a three-dimensional material functioning as a cathode can be installed so as not to be alternately short-circuited and electrically connected to form a fixed-bed type bipolar electrolytic cell.

[0008] Activated carbon, graphite,
When using a carbon-based material such as carbon fiber and treating raw water while generating oxygen gas from the anode, the dielectric is easily oxidized by oxygen gas and easily dissolved as carbon dioxide gas. In order to prevent this, a porous material which is usually used as an insoluble metal electrode by coating a platinum group metal oxide such as iridium oxide or ruthenium oxide on a base material such as titanium on the side where the dielectric material is positively polarized is used. What is necessary is just to install in a contact state, and to generate | occur | produce oxygen mainly on this porous material.
Also, as another type of fixed-bed type bipolar electrolytic cell, for example, a power supply anode and a cathode are installed in a cylindrical electrolytic cell body, and a large number of conductive electrodes functioning as three-dimensional electrodes are provided between the power supply electrodes. There is an electrolytic cell in which particles for forming a fixed bed and insulating particles made of a synthetic resin or the like having a smaller number of particles than the particles for forming a fixed bed are almost uniformly mixed. In the electrolytic cell, when a potential is applied by applying a current between both power supply electrodes, the fixed bed forming particles are polarized in the same manner as the dielectric, and one end thereof is positively charged and the other end is negatively charged, thereby forming each fixed bed. A potential is generated in the particles for use, and a function of sterilizing microorganisms in raw water is given to each particle. The insulating particles have a function of preventing the two power supply electrodes from being electrically connected by the conductive fixed bed forming particles to cause a short circuit.

When a monopolar fixed-bed electrolytic cell is used, the above-mentioned dielectric or one of the three-dimensional materials which independently function as an anode or a cathode can be used with or without a diaphragm. To be installed inside. When the raw water described above is supplied to the fixed-bed type three-dimensional electrode electrolytic cell, the microorganisms in the raw water come into contact with the anode or cathode of the electrolytic cell, the dielectric, the particles for forming the fixed bed, or the like by the liquid flow, and at the surface thereof. It is thought that sterilization is performed by receiving a strong oxidation-reduction reaction or contacting a high-potential current, weakening its activity or killing itself.

Therefore, in the method of the present invention, it is sufficient if the microorganisms in the raw water come into contact with the electrode, the dielectric, the particles for forming the fixed bed, etc., to which a voltage is applied. It is not essential to cause a substantial electrolytic reaction accompanied by gas generation, but rather it is preferable to apply a low potential at which no substantial electrolytic reaction occurs to the electrode surface. This causes a chemical change due to gas generation to the raw water component when a substantial electrolytic reaction occurs, which may cause a complicated effect on the raw water and constantly maintain a constant processing performance. In addition, wasteful electric power is used for a gas generation reaction other than sterilization of microorganisms, which is uneconomical. In particular, at a potential where a large amount of oxygen gas or hydrogen gas is generated, an oxidation-reduction reaction may be caused by these gases, and the generated gas may cover the electrode surface and deteriorate the electrode performance. Therefore, in the electrochemical treatment of the present invention, the applied potential is set to +0.2 to +1.2 V (vs. S.
CE), the cathode potential is 0 to -1 without substantial hydrogen generation.
0 V (vs. SCE) .

[0011] By this electrochemical treatment, microorganisms in the raw water that easily cause contamination of the ion exchange resin are killed. Therefore, when the raw water subjected to the electrochemical treatment is supplied to an ion exchange resin tower or the like to produce deionized water, the microorganisms do not grow in the ion exchange resin layer and the ion exchange resin is not contaminated by the microorganisms for a long time. It is possible to produce high-purity deionized water over a wide range. Furthermore, raw water such as tap water contains calcium ions and magnesium ions in addition to the above-mentioned microorganisms. When the tap water is supplied to an ion exchange resin tower or the like as it is, the calcium ions and magnesium ions become loads on the ion exchange resin. However, when the raw water is electrochemically treated using the fixed-bed type three-dimensional electrode electrolytic cell, the raw water is precipitated as a hydroxide of calcium ions or magnesium ions on the cathode or the three-dimensional electrode of the electrolytic cell or, for example, electrolytically treated. Since it is collected from the raw water by being collected by a filter or the like installed at the liquid outlet of the tank, the ion load of the ion exchange resin can be reduced, and the processing capacity can be increased.

Regardless of the type of electrode used,
If there is a gap in the electrolytic cell through which the raw water to be treated flows so that the liquid can flow without coming into contact with the electrodes, dielectrics, or fine particles, the raw water treatment efficiency will decrease. It is desirable to arrange so as not to pass. Even if the anode chamber and the cathode chamber are formed by partitioning the inside of the electrolytic cell with a diaphragm, energization can be performed as it is without using a diaphragm, but without using a diaphragm and the distance between the electrodes or a dielectric material. In the case where the distance between the electrode and the dielectric or between the dielectrics is reduced, for example, a mesh spacer made of an organic polymer material or the like may be inserted between the electrodes or between the dielectrics as an electrically insulating spacer to prevent a short circuit. it can. When a diaphragm is used, it is desirable to use a porous material having an opening ratio of 10% or more and 95% or less, preferably 20% or more and 80% or less, so as not to hinder the movement of raw water flowing therethrough. Must have at least micropores having a pore size that allows the raw water to pass through.

The flow rate of the raw water supplied to the electrolytic cell may be determined so that the raw water can efficiently contact the surface of the electrode or the like. Because the contact with the dielectric and the particle surface is reduced,
It is preferable to form a turbulent state, and it is particularly preferable to form a turbulent flow having a Reynolds number of 500 or more. Further, it is desirable to install a filter at least before and after the electrolytic cell used in the present invention, particularly before the electrolytic cell to remove solid impurities from raw water before entering the electrolytic cell. In the electrolytic cell used in the method of the present invention, a leakage current occurs in the electrolytic cell, and the leakage current flows from the electrolytic cell through raw water to another member such as a pipe, and the pipe may be electrochemically corroded and eluted. Therefore, a member having higher conductivity than the raw water is installed so that one end thereof can be grounded, and the leakage current is provided on the back surface of the electrode where the positive and negative electrodes do not face each other and / or in the inlet / outlet pipe of the electrolytic bath. Can be shut off.

[0014] The raw water, which has been treated electrochemically by the fixed-bed type three-dimensional electrode electrolytic cell to kill microorganisms and to remove hardness components and the like to improve its purity, is then brought into contact with an ion exchange resin to be removed. It is ionized and produces higher purity deionized water. The ion exchange resin to be used may be any of those conventionally used in the production of deionized water without limitation, and may be a granular or powdery weakly acidic cation exchange resin (having, for example, a carboxylic acid group as an exchange group) or a strong acid. Cation exchange resin (for example, having a sulfonic acid group as an exchange group) or weakly basic anion exchange resin (for example, having a tertiary amine group as an exchange group) or strongly basic anion exchange resin (for example, a quaternary amine group as an exchange group) Is used alone or in combination to produce deionized water. The ion-exchange resin may be brought into contact with the raw water that has been subjected to the electrochemical treatment in any manner. For example, an ion-exchange column containing the ion-exchange resin through a closed pipe from the electrolytic cell may be used in order to suppress contamination of impurities. The raw water is guided to the above, and the raw water is sufficiently brought into contact with an ion exchange resin to be deionized. Then, the raw water is taken out from an ion exchange tower or the like to obtain high-purity deionized water. Among the ion exchange resins, hydrogen-type strongly acidic cation exchange resins are particularly effective in removing hardness components such as calcium and magnesium and sterilizing microorganisms.
On the other hand, a strongly basic anion exchange resin of a hydroxyl group type is effective for removing organic substances and sterilizing microorganisms. However, since treated water is treated in the above-mentioned electrolytic cell, and particularly, hardness components are removed and sterilized, the above treatment is performed. When water comes into contact with the cation and anion exchange resins, a synergistic effect with the sterilization action of microorganisms in both exchange resins, by treatment with the electrolytic cell and the ion exchange resins, while minimizing contamination of the ion exchange resins. It is possible to produce high-purity water having an extremely low microorganism content.

Next, preferred examples of an electrolytic cell which can be used in the present invention and a method for producing high-purity deionized water using the electrolytic cell and an ion exchange resin will be described with reference to the accompanying drawings. It is not limited. FIG.
FIG. 2 is a schematic vertical sectional view showing an example of a fixed-bed type bipolar electrolytic cell that can be used as an electrolytic cell in the method of the present invention. FIG. 2 shows high-purity deionized water from raw water using the electrolytic cell of FIG. 1 and an ion exchange tower. It is a flowchart of the system which produces water. A meshed power supply anode terminal 3 and a power supply cathode terminal 4 are provided near an upper end and a lower end of a cylindrical electrolytic cell main body 2 having upper and lower flanges 1, respectively. The electrolytic cell main body 2 is preferably formed of an electric insulating material that can withstand long-term use or re-use. Particularly, synthetic resins such as polyepichlorohydrin, polyvinyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, and poly (ethylene chloride) are used. And a phenol-formaldehyde resin. The anode terminal 3 that gives a positive DC voltage is, for example, a carbon material (eg, activated carbon, charcoal, coke, coal, etc.), a graphite material (eg, carbon fiber, carbon cloth, graphite, etc.), a carbon composite material (eg, Activated carbon fiber non-woven fabric (for example, KE-1000 felt, Toyobo Co., Ltd.), or a material having platinum, platinum, palladium or nickel supported thereon, and a dimensionally stable electrode
(Platinum group oxide coated titanium material), formed of platinum coated titanium material, nickel material, stainless steel material, iron material and the like. The cathode terminal 4 which faces the anode terminal 3 and gives a negative DC voltage is made of, for example, platinum, stainless steel, titanium, nickel, copper, hastelloy, graphite, carbon material, mild steel or a metal material coated with a platinum group metal. ing.

A plurality of sponge-like fixed beds 5 are stacked between the electrode terminals 3 and 4 in the illustrated example, and between the fixed beds 5 and between the fixed bed 5 and the electrode terminals 3. 4, four porous diaphragms or spacers 6 are sandwiched. Each fixed bed 5 is in close contact with the inner wall of the electrolytic cell main body 2 and does not pass through the inside of the fixed bed 5 so that the leakage flow of the processing liquid flowing between the fixed bed 5 and the side wall of the electrolytic cell main body 2 is minimized. Are located. When a diaphragm is used, a woven fabric, an unglazed plate, a particle sintered plastic, a perforated plate, an ion exchange membrane, or the like is used as the diaphragm, and a woven fabric, a perforated plate, a mesh made of an electrically insulating material is used as a spacer. , A rod-shaped material or the like is used. As shown in FIG. 2, the outlet side of the electrolytic cell main body 2 is connected to a cylindrical ion exchange tower 9 containing a granular ion exchange resin 8. When electricity is supplied to the electrolytic cell main body 2 while supplying raw water such as tap water from below as shown by arrows in FIG.
As shown in the figure, the lower surface is polarized positively and the upper surface is negatively polarized, and an electric potential is generated in the fixed bed 5 and between the fixed beds 5, and the raw water flowing in the electrolytic cell comes into contact with the fixed bed 5 having this electric potential and Treatments such as sterilization of contained molds and bacteria and removal of calcium ions and magnesium ions are carried out and taken out from above the electrolytic cell. The purity of the raw water taken out is significantly higher than that of the raw water before being supplied to the electrolytic cell. When this raw water is supplied to the ion exchange tower 9, the ion exchange resin 8 in the ion exchange tower 9 comes into contact only with the raw water that has been subjected to the electrochemical treatment and has been cleaned. And the ion load is reduced, so that the processing capacity in the production of ionic water can be increased.

FIG. 3 shows another example of a bipolar-type fixed-bed electrolytic cell which can be used in the present invention. The electrolytic cell is a side of the fixed bed 5 of the electrolytic cell shown in FIG. In other words, a mesh-shaped insoluble metal material 7 is placed in close contact with the side to be positively polarized, and the other members are the same as those in FIG. The fixed bed 5 to which the DC voltage is applied has the largest polarization at both ends, and when gas generation is involved, gas generation occurs most severely at both ends. Accordingly, the end of the fixed bed 5 toward the power supply cathode 4 of the fixed bed 5, which is the most strongly anodic polarized, that is, generates the most intense oxygen gas, dissolves fastest. As shown in the figure, when the insoluble metal material 7 is installed in this portion, most of the oxygen gas is removed from the insoluble metal material 7 because the overvoltage of the insoluble metal material 7 is lower than that of the carbon-based material forming the fixed bed 5. Since the generated fixed bed 5 hardly comes into contact with the oxygen gas, the dissolution of the fixed bed 5 is effectively suppressed. Raw water such as tap water supplied to the electrolytic cell 2 is treated in the same manner as in FIG. 1 and then supplied to the ion exchange tower.

FIG. 4 shows another example of a bipolar-type fixed-bed electrolytic cell which can be used in the method of the present invention. A meshed power supply anode 13 and a power supply cathode 14 are provided near the upper end and the lower end of a cylindrical electrolytic cell main body 12 having a flange 11 at the top and bottom, respectively. The electrolytic cell body 12 is preferably formed of an electrically insulating material, particularly a synthetic resin, that can withstand long-term use or re-use. The two power supply electrodes 13,
A large number of fixed bed forming particles 15 formed of a conductive material such as a carbon-based material and a smaller number of the fixed bed forming particles 15, for example, insulating particles 18 made of a synthetic resin are substantially uniformly mixed between the conductive materials. ing. The insulating particles 18 have a function of preventing the power supply anode 13 and the power supply cathode 14 from being completely short-circuited. When electricity is supplied to the electrolytic cell having such a configuration while supplying raw water from below as indicated by an arrow, each of the fixed bed forming particles 15 becomes negative on the power supply anode 13 side and the power supply cathode
The 14 side is positively polarized and functions as a three-dimensional electrode having a huge surface area. The raw water is sterilized in the same manner as in the electrolytic cell shown in FIGS. 1 and 3, and then supplied to an ion exchange tower to remove high-purity water. Ionized water is produced.

FIG. 5 exemplifies a monopolar fixed-bed electrolytic cell that can be used in the present invention. A mesh-shaped power supply anode 23 and a power supply cathode 24 are provided near an upper end and a lower end of a cylindrical electrolytic cell body 22 having upper and lower flanges 21, respectively.
Is provided. The electrolytic cell main body 22 is preferably formed of an electrically insulating material that can withstand long-term use or re-use, especially a synthetic resin. A pair of fixed floors 25 made of a conductive material such as carbon fiber in a felt shape with a diaphragm 26 interposed therebetween is filled in the anode chamber and the cathode chamber between the power feeding electrodes 23 and 24, and the anode chamber and the cathode chamber are filled. The felt-like carbon fibers in the room are electrically connected to the power supply anode 23 and the power supply cathode 24, respectively, and the fixed floor in the anode room is positively charged and the fixed floor in the cathode room is negatively charged. When electricity is supplied to this electrolytic cell while supplying raw water from below as shown by arrows, FIG.
3 and 4, the fixed bed 25 functions as a three-dimensional electrode having an enormous surface area to sterilize microorganisms such as fungi and bacteria in raw water.

[0020]

EXAMPLES Hereinafter, examples of the production of high-purity deionized water from tap water according to the method of the present invention will be described, but the examples do not limit the method of the present invention.

EXAMPLE 1 High-purity treated water was produced from tap water by using the electrolytic cell shown in FIG. 1 together with an ion exchange tower as shown in FIG. The electrolytic cell is made of vinyl chloride resin and has a height of 100.
mm, an inner diameter of 50 mm, and three fixed beds made of carbon fiber having a porosity of 60% and having a diameter of 50 mm and a thickness of 10 mm are provided inside the cylindrical body. It was sandwiched between four polyethylene resin diaphragms having a thickness of 1.5 mm, and the upper and lower diaphragms were placed in contact with a mesh anode terminal and a cathode terminal each having a diameter of 48 mm and a thickness of 1.0 mm made of titanium each having platinum plated on the surface thereof. . The ion exchange tower is made of vinyl chloride and has a height of 500 m.
m, a cylinder having an inner diameter of 50 mm, and a particle size in the ion exchange tower.
A sodium-type ion-exchange resin Amberlite IR-120B (trade name) of 0.45 to 0.60 mm (800 g) was accommodated therein.

Tap water having a number of microorganisms of 25 / ml and a calcium ion concentration of 21.6 ppm and a magnesium concentration of 9.7 ppm was supplied as raw water to the electrolytic cell at a rate of 1.2 liter / min. The tap water taken out of the electrolytic cell was led to the ion exchange tower as it was, and brought into contact with an ion exchange resin, and then taken out of the ion exchange tower as high-purity treated water. The number of microorganisms in the high-purity treated water removed from the ion exchange tower was 1 / ml, the calcium ion concentration was 0.2 ppm, and the magnesium ion concentration was 0.
ppm. After supplying tap water to the electrolytic cell and the ion exchange tower (the ion exchange tower was regenerated once a day by the usual method) for 14 days, the number of microorganisms and calcium ion concentration of the treated water taken out of the ion exchange tower And the magnesium ion concentration were measured again to be 0-1 / ml, 0.2-0.3 ppm and 0-0.1 ppm, respectively.
And the purity of the obtained treated water was almost the same as the purity of the initial treated water. The measured values of calcium and magnesium are shown in terms of calcium carbonate.

[0022]

Comparative Example 1 The same tap water as in Example 1 was used, and the tap water was directly supplied as raw water to the ion exchange tower of Example 1 to produce treated water by ion exchange. When the number, calcium ion concentration and magnesium ion concentration were measured, they were 18 / ml and 0.1, respectively.
They were 2 ppm and 0.1 ppm. After the supply of tap water to the ion exchange tower (the ion exchange tower was regenerated once a day by the ordinary method) was continued for 14 days, the number of microorganisms, calcium ion concentration and magnesium ion concentration were measured again. Parts / ml, 0.5-0.7 ppm and 0.2-0.4 ppm, the purity of the resulting treated water was much lower than the purity of the initial deionized water.

[0023]

Example 2 Treated water was produced from tap water using the electrolytic cell and ion exchange tower used in Example 1. Calcium chloride and magnesium chloride were dissolved in the tap water of Example 1, and tap water having a calcium ion concentration of 20.0 ppm and a magnesium ion concentration of 10.0 ppm was used as raw water. This raw water was subjected to an electrochemical treatment and an ion exchange treatment under the same conditions as in Example 1, and the calcium ion concentration and the magnesium ion concentration in the high-purity treated water taken out of the ion exchange tower were measured to be 0.17 pp.
m and 0.05 ppm. After continuing the supply of tap water to the electrolytic cell and the ion exchange tower for 14 days, when the calcium ion concentration and the magnesium ion concentration of the treated water were measured again, they were 0.21 ppm and 0.06 ppm, respectively.
The purity of the obtained treated water was almost the same as that of the initial deionized water.

[0024]

Comparative Example 2 The same tap water as in Example 2 was used, and the tap water was directly supplied as raw water to the ion exchange tower of Example 1 to produce treated water by ion exchange. When the ion concentration and the magnesium ion concentration were measured, they were 0.35 ppm and 0.20 ppm, respectively. After continuing the supply of tap water to the ion exchange tower for 14 days, when the calcium ion concentration and the magnesium ion concentration were measured again, they were 1.72 ppm and 1.15, respectively.
ppm, and the purity of the obtained treated water was significantly lower than the purity of the initial treated water.

[0025]

Example 3 Treated water was produced from tap water using the electrolytic cell and ion exchange tower used in Example 1. E. coli was added to the tap water of Example 1 to make the number of E. coli 1200 / ml, and tap water was used as raw water. This raw water was subjected to an electrochemical treatment and an ion exchange treatment under the same conditions as in Example 1, and the number of E. coli in the high-purity treated water taken out from the ion exchange tower was measured to be 98 / ml. After the supply of raw water to the electrolytic cell and the ion exchange tower was continued for 7 days, the number of Escherichia coli in the treated water was measured again. As a result, the number of E. coli was 95 / ml. The purity was almost the same.

[0026]

Comparative Example 3 The same tap water as in Example 3 was used as raw water, and the raw water was directly supplied to the ion exchange tower of Example 1 to produce treated water by ion exchange. Was 685 particles / ml. After continuing the supply of raw water to the ion exchange tower for 7 days,
When the number of microorganisms was measured again, it was 980 / ml, and the purity of the obtained treated water was much lower than the purity of the initial treated water.

[0027]

Example 4 In an ion exchange column having a height of 1500 mm and an inner diameter of 120 mm, 2400 g of hydrogen type cation exchange resin Amberlite IR-120B (trade name) having a particle size of 0.45 to 0.60 mm and a hydroxyl group type anion exchange resin IRA-410 (product name) 4800
g. 21.6 ppm of calcium ion and 9.7 pp of magnesium at 25 microorganisms / milliliter
The raw water (electrical conductivity is 282 μS / cm ² ) containing humic substances obtained by immersing peat in tap water having a total organic carbon (TOC) of 2.8 ppm was added to Example 1. The same electrolytic cell was supplied at a rate of 1.2 liter / min. The raw water taken out of the electrolytic cell was led to the ion exchange tower as it was, and brought into contact with the ion exchange resin, and then taken out of the ion exchange tower as high-purity treated water.

The number of microorganisms in the high-purity treated water taken out of the ion exchange tower is 1 / ml, and the TOC is
At 0.7 ppm, the electrical conductivity was 0.22 μS / cm ² .
After the supply of tap water to the electrolytic cell and the ion exchange tower (the ion exchange tower was regenerated by a standard method every time about 1000 liters of raw water was treated) for 6 months, the treated water extracted from the ion exchange tower When the number of microorganisms was measured again, the number of microorganisms was 0-1 / ml, and TOC was 0.8 pp.
m, the electric conductivity was 0.1 to 0.3 μS / cm ² , and the purity of the obtained treated water was almost the same as the purity of the initial treated water.

[0029]

Comparative Example 4 The same tap water as in Example 3 was used as raw water, and the raw water was directly supplied to the ion exchange tower of Example 3 to produce treated water by ion exchange. After continuing the supply of raw water to the ion exchange tower (the ion exchange tower was regenerated by a standard method every time about 1000 liters of raw water was treated),
When the number of microorganisms in the treated water taken out from the ion exchange tower was measured again, the number of microorganisms was 3 to 7 / ml, TOC was 1.4 ppm, and electric conductivity was 0.2 to 0.7 μS.
/ Cm ² , each of which is larger than that of Example 4.

In the method of the present invention, when deionizing raw water containing impurities with an ion-exchange resin to produce high-purity deionized water, the raw water is actually contacted with the ion-exchange resin before the raw water is brought into contact with the ion-exchange resin.
Electrochemical treatment without qualitative gas generation removes microorganisms in the raw water without causing a chemical change in the raw water, thereby preventing contamination of the ion-exchange resin. This is a method in which the frequency of resin exchange and the frequency of regenerative treatment are reduced so that high-purity deionized water can be stably produced (claim 1). The method of the present invention is directed to raw water containing microorganisms and hardness components such as tap water, and connects the electrolytic tank to an ion exchange tower or the like filled with an ion exchange resin without performing pretreatment or post treatment of the raw water. Only by allowing the ion-exchange resin to flow through, it is possible to effectively prevent contamination of the ion exchange resin and to constantly obtain high-purity deionized water.

That is, when the raw water is supplied to the fixed-bed type three-dimensional electrode electrolytic cell, the microorganisms in the raw water come into contact with a potential-applied anode or cathode, a dielectric substance, particles for forming a fixed bed, etc. Undergoes an oxidation-reduction reaction or contacts a high-potential electric current, and its activity is weakened or it is killed and sterilized, and calcium ions and magnesium ions contained in the raw water are converted from the raw water as hydroxides. It is removed and the load on the ion exchange resin can be reduced.
Therefore, the processing capacity of the ion exchange resin can be increased. Further , a filter is installed after the electrolytic cell ,
The raw water electrochemically treated in the tank is filtered by the filter
After passing through, make contact with the ion exchange resin
Then, (claim 2), sedimentation in the electrolytic cell and death of microorganisms
The debris and the like are removed, so that contamination of the ion exchange resin can be more effectively prevented. As the ion exchange resin, a weakly acidic cation exchange resin, a strongly acidic cation exchange resin, a weakly basic anion exchange resin, a strongly basic anion exchange resin, or the like can be used (claim 3), and each resin has a hardness component removed. Desired high-purity water can be produced by selecting a resin to be used in accordance with the application, having a unique effect on sterilization.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing an example of a fixed bed type bipolar electrolytic cell that can be used as an electrolytic cell in the method of the present invention.

FIG. 2 is a flowchart of a system for producing high-purity deionized water from raw water using the electrolytic cell and the ion exchange tower of FIG. 1;

FIG. 3 is a schematic longitudinal sectional view showing another example of a bipolar fixed-bed electrolytic cell that can be used in the present invention.

FIG. 4 is a schematic longitudinal sectional view showing another example of a bipolar fixed bed electrolytic cell that can be used in the method of the present invention.

FIG. 5 is a schematic longitudinal sectional view illustrating a monopolar fixed bed electrolytic cell that can be used in the present invention.

[Description of Signs] 1 ... Flange 2 ... Electrolyzer main body 3,4 ...
Electrode terminal for power supply 5 ・ ・ ・ Fixed bed 6 ・ ・ ・ Spacer 7 ・ ・ ・ Insoluble metal material 8 ・ ・ ・ Ion exchange resin 9 ・ ・ ・ Ion exchange tower 11 ・ ・ ・ Flange 12 ・ ・ ・ Electrolyzer main body 13, 14 ・ ・ ・ Power supply electrode terminal 15 ・ ・ ・ Fixed bed forming particles 18 ・ ・ ・ Insulating particles 21 ・ ・ ・ Flange 22 ・
..Electrolyzer main bodies 23, 24 ... Electrode terminals for power supply
25 ... fixed bed 26 ... diaphragm

Continued on the front page (72) Inventor Mina Sato 1 Konica Corporation, Sakura-cho, Hino-shi, Tokyo (72) Inventor Takeshi Nakazawa 5-5-16-1 Hongo, Bunkyo-ku, Tokyo Organo Corporation (72) Invention Person Sadaji Kuzumaki 1-4-9 Kawagishi, Toda City, Saitama Prefecture Inside the Research Laboratory of Organo Co., Ltd. (56) References JP-A-60-71098 (JP, A) JP-A-53-385 (JP, B2) 53-14861 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C02F 1/42 C02F 1/46-1/48 B01J 47/00-47/14

Claims (3)

(57) [Claims] 1. A method for producing high-purity water by contacting raw water containing impurities with an ion-exchange resin, wherein the raw water has a fixed bed type three-dimensional electrode having an anode potential of +0.2 to +1.2 V.
(Vs. SCE), the cathode potential becomes 0 to -1.0 V (vs. SCE)
A method for producing high-purity water, comprising supplying the raw water to the fixed-bed type three-dimensional electrode electrolytic cell to which the voltage is applied, electrochemically treating the raw water, and then contacting the raw water with the ion-exchange resin for treatment. 2. The method according to claim 1, wherein the fixed bed type three-dimensional electrode electrolytic cell is electrified.
After passing the chemically treated raw water through a filter
2. The method according to claim 1 , further comprising contacting the ion exchange resin with the ion exchange resin . 3. The method according to claim 1, wherein the ion exchange resin is at least one of a weakly acidic cation exchange resin, a strongly acidic cation exchange resin, a weakly basic anion exchange resin and a strongly basic anion exchange resin. .