JPH08252579A - Porous ion exchanger and production of deionized water - Google Patents

Abstract

PURPOSE: To produce a highly pure deionized water stably and continuously over a long period of time. CONSTITUTION: A porous ion exchanger having a porous structure in which a mixture of a cation exchange resin and an anion exchange resin are bound by using a binder polymer and having >=30kg.cm<-1> .h<-1> water permeability at 0.35kg/cm<2> is disposed in a desalting chamber of an electrodialyzer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a liquid-permeable porous ion exchanger, and more particularly to a porous ion exchanger for producing deionized water by electrodialysis.

[0002]

2. Description of the Related Art As a method for producing deionized water, a method is generally used in which water to be treated is flowed through a packed bed of ion exchange resin so that impurity ions are adsorbed by the ion exchange resin and removed to obtain deionized water. . Here, the ion exchange resin having a reduced adsorption capacity is regenerated by using an acid or an alkali. However, this method has a problem that the waste liquid of the acid or alkali used for the regeneration is discharged, and therefore a deionized water production method that does not require regeneration is desired.

From such a point of view, a self-regenerating type electrodialysis deionized water production method in which an ion exchange resin and an ion exchange membrane are combined has attracted attention in recent years. In this method, a mixture of an anion exchanger and a cation exchanger is placed in a desalting chamber of an electrodialysis device in which an anion exchange membrane and a cation exchange membrane are alternately arranged, and water to be treated is placed in the desalting chamber. It is a method of producing deionized water by applying voltage while flowing and performing electrodialysis.

Regarding this method, a method of limiting the width and thickness of the desalting chamber (Japanese Patent Laid-Open No. 61-107906) or a method of using an ion exchange resin having a uniform diameter in the desalting chamber (special Kaihei 3-207487), a method in which the ion exchange resin filled in the portion through which the water to be treated first passes is anion exchange resin (Japanese Patent Laid-Open No. 4-71624), and the ion exchanger filled in the desalting chamber is the ion exchange resin. A method of using a mixture of ion exchange fibers (Japanese Patent Laid-Open No. 5-277344) and the like have been studied.

However, since the cross-linked ion exchange resin is not fixed as the ion exchanger to be put in the desalting chamber, the ion exchange resin having the same sign is agglomerated during use or particles or fibers of the ion exchange resin are generated due to the water flow. There was a problem in the stability of the purity of the water obtained by crushing and preventing efficient desalination and regeneration.

As a method for compensating for these drawbacks, a method of introducing a ion-exchange group by performing radiation grafting on a nonwoven fabric such as polyethylene or polypropylene (Japanese Patent Laid-Open No. 5-6472).
6, JP-A-5-131120), and an ion-exchange polymer and a reinforcing polymer in the form of a composite fiber having a sea-island structure, which is then molded into a sheet (JP-A-6-79268).

[0007] In these methods, the ion exchanger is immobilized, but there are drawbacks such as the need to use radiation, the process for producing the composite fiber is complicated, and the mechanical strength is not always sufficient. It was

[0008]

DISCLOSURE OF THE INVENTION The present invention is a method for producing a self-regenerating electrodialysis deionized water in which an ion exchanger and an ion exchange membrane are combined, and is immobilized regardless of complicated steps such as the use of radiation. The purpose of the present invention is to produce an ion exchanger and stably produce highly pure deionized water.

[0009]

The present invention provides a porous ion exchanger in which cation-exchange resin particles, anion-exchange resin particles or a mixture thereof are bonded using a binder polymer, and the pressure is 0.35 kg / cm. There is provided a liquid-permeable ion exchanger having a water permeability in ² of 30 kg · cm ⁻¹ · h ⁻¹ or more.

For water permeability, a sample of a columnar body (for example, a prism or a cylinder) having two bottom surfaces parallel to each other was prepared, and water was prevented from leaking from the side surface, and 0.35 kg / cm from one bottom surface. Water is introduced at a pressure, and the mass of water flowing out from the other bottom surface is measured and obtained. At this time, the area of the bottom surface is A (cm ² ), the height of the columnar body, that is, the distance between the bottom surfaces is L (cm), and the water permeation amount per hour is W (k
g / h), the water permeability is WL / A (kgcm)
⁻¹ · h ⁻¹ ). Although A and L can be arbitrarily determined, A is about 1 to 1000 cm ² and L is 1 to 100 cm.
It is preferable to measure the degree.

The water permeability of the porous ion exchanger is 30 kg · cm ⁻¹ · h ^{−1 at} a pressure of 0.35 kg / cm ² .
It is preferable that it is above. If it is less than 30 kg · cm ⁻¹ · h ⁻¹ , the flow path resistance when the present porous ion exchanger is placed in the flow path becomes large and the amount of treated water decreases, or a high pressure is required for operation. It is not desirable because it is necessary. It is particularly preferable that the water permeability is 100 kg · cm ⁻¹ · h ⁻¹ or more. The higher the water permeability, the better,
In order to make a material with high water permeability, it is necessary to make a material with large voids, which may reduce the ion exchange capacity and mechanical strength, so the practical upper limit is 10,000 kg · cm ^−1.
・ It is about h ^-1 .

When the porous ion exchanger has anisotropy,
Water permeability is measured in the direction corresponding to the water flow when the ion exchanger is placed in the channel. Materials that swell in water are water permeable in the environment in which they will be used. Measure the temperature under the same conditions used.

The present invention also provides a porous ion exchanger prepared by mixing a mixture of cation-exchange resin particles and anion-exchange resin particles with a binder polymer or a binder polymer solution, followed by heat molding or solvent drying. Provided is a method for producing a liquid-permeable ion exchanger to be obtained.

The present invention further provides a deionized water production method in which an ion exchanger is housed in a desalting chamber of an electrodialysis apparatus in which a cation exchange membrane and an anion exchange membrane are alternately arranged between a cathode and an anode. A method for producing deionized water by energizing while flowing water to be treated in a deionization chamber of an apparatus, wherein a method for producing deionized water using the porous ion exchanger as the ion exchanger is provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The material of the ion exchange resin particles is not particularly limited, and various ion exchange resins can be used. Specifically, a styrene-divinylbenzene copolymer having an ion exchange group introduced therein is preferable. As the ion exchange group, the cation exchange group is a sulfonic acid type which is a strong acid,
The anion exchange group is preferably a quaternary ammonium salt type or a pyridinium salt type, which is a strong base, from the viewpoint of ion exchangeability and chemical stability.

The ion exchange capacity of the ion exchange resin particles is
0.5-7 meq / g dry resin is preferred. If the ion exchange capacity is smaller than 0.5 meq / g dry resin, the ion exchange performance will be insufficient, and when a porous ion exchanger is placed in the desalting chamber of the electrodialysis device, adsorption and desorption of ions will occur. It is not preferable because the salt is not sufficiently added and the purity of the treated water may decrease. If the ion exchange capacity is larger than 7 meq / g dry resin, the stability of the ion exchange resin itself may be impaired, which is not preferable. When the ion exchange capacity is 1 to 5 meq / g dry resin, a resin having a high ion exchange capacity can be obtained, and the performance stability is also excellent, which is particularly preferable.

The particle size of the ion exchange resin particles is 50 to 10
It is preferably in the range of 00 μm. Particle size is 50 μm
When it is smaller than the above range, the pore diameter of the porous ion exchanger may be small and the water permeability may be lowered, which is not preferable. When the particle size is larger than 1000 μm, the surface area of the ion exchanger is insufficient, and the treatment efficiency of ion exchange may be reduced, which is not preferable. More preferably, the particle size of the ion exchange resin particles is 300 to 600 μm. The ion exchange resin may be synthesized so as to have the above particle size range, or may be pulverized so as to have the above particle size range.

The shape of the ion exchange resin particles is not particularly limited, and a spherical shape is preferable because it has excellent water permeability.

With respect to the porosity of the porous ion exchanger, it is preferable that the porosity of the open pores involved in the passage of the liquid is 5 to 50% by volume. When the porosity is less than 5% by volume, the flow rate of the liquid decreases and the pressure loss increases, which is not preferable. When the porosity is larger than 50% by volume, the mechanical strength of the porous ion exchanger is lowered and the handling may be difficult, which is not preferable. When the porosity is 10 to 40% by volume, water permeability is good, desalination performance is excellent, and highly purified treated water is obtained, which is particularly preferable. With this porosity, the voids that do not actually contact the liquid when the porous ion exchanger is placed in the liquid flow path are:
It is not regarded as an open space to the outside.

In the porous ion exchanger of the present invention, by binding with the binder polymer, contact between the ion-exchange resin particles is improved, and the binder polymer is present between the ion-exchange resin particles. There are aspects where contact is impaired. For the purpose of arranging in the desalting chamber of the electrodialysis device, the porous ion exchanger preferably has low electric resistance.

The specific resistance when the porous ion exchanger is placed in the desalting chamber of the electrodialysis device is such that the ion exchange resin particles contained in the porous ion exchanger are desalted in the same device without a binder. It is preferable that the value is not more than twice the specific resistance measured by filling the chamber. If the specific resistance is more than twice, the voltage during operation increases and the running cost increases, which is not preferable. It is more preferable if the specific resistance thus measured is lower than that for the resin particles.

The porous ion exchanger may be either one containing only cation exchange resin particles, one containing only anion exchange resin particles, or one containing a mixture of cation exchange resin particles and anion exchange resin particles. In the case of those containing cation exchange resin particles and anion exchange resin particles, not only are they uniformly mixed, but the part containing only cation exchange resin particles and the part containing only anion exchange resin particles have a sea-island structure. Alternatively, the layered structure may have a phase separation structure.

When used by being placed in the desalting chamber of the electrodialysis device, it is preferable that the dialysis chamber contains cation exchange resin particles and anion exchange resin particles. The ratio of the anion exchange resin particles is preferably such that the total ion exchange capacity ratio is cation exchange resin / anion exchange resin = 30/70 to 60/40. If the total ion exchange capacity ratio is out of this range, the purity of the treated water may decrease, which is not preferable.

The weight fraction of binder polymer is preferably 0.5 to 20%, based on the weight of the porous ion exchanger. If the weight fraction is less than 0.5%, the mechanical strength of the porous ion exchanger is reduced and handling becomes difficult, which is not preferable. If the weight fraction is more than 20%, the surface of the ion-exchange resin particles is coated with the binder polymer to lower the adsorptivity, and the porosity is lowered to lower the water permeability, which is not preferable. The more preferable weight fraction of the binder polymer is 1 to 5%.

The binder polymer is preferably a thermoplastic polymer or a solvent-soluble polymer from the viewpoint of the method for producing a porous ion exchanger. Furthermore, a polymer having an ion exchange group is more preferable because it can improve the ion exchange performance.

The ion-exchange capacity of the binder polymer having ion-exchange groups is preferably 0.5 to 5 meq / g dry resin. When the ion exchange capacity is smaller than 0.5 meq / g dry resin, the ion exchange performance is insufficient,
When a porous ion exchanger is arranged in the desalting chamber of the electrodialysis device, adsorption of ions and desalting are not sufficiently performed, and the purity of treated water may be deteriorated, which is not preferable. If the ion exchange capacity is larger than 5 meq / g dry resin, the stability of the ion exchange resin itself may be impaired, which is not preferable. When the ion exchange capacity is 0.8 to 3 meq / g dry resin, a resin having a high ion exchange capacity can be obtained, and the performance stability is particularly excellent, which is particularly preferable.

As the binder polymer, specifically, the followings can be preferably used. First, as the thermoplastic polymer, low density polyethylene, linear low density polyethylene, ultra high molecular weight high density polyethylene, polypropylene,
Examples thereof include polyisobutylene, vinyl acetate, ethylene-vinyl acetate copolymer and the like. As a solvent-soluble polymer, natural rubber, butyl rubber, polyisoprene, polychloroprene, styrene-butadiene rubber, nitrile rubber,
Examples thereof include vinyl chloride-fatty acid vinyl ester copolymers.

Further, as a polymer having an ion exchange group, polystyrene sulfonic acid, polyvinyl sulfonic acid, poly (2-acrylamido-2-methylpropane sulfonic acid), polyacrylic acid, polymethacrylic acid, perfluorosulfonic acid are contained. Mention may be made of polymers or polymers containing salts thereof. Further, a polymer containing polyvinylbenzyltrimethylammonium chloride can be mentioned. Furthermore, poly (4-vinylpyridine), poly (2-vinylpyridine), poly (dimethylaminoethyl acrylate), poly (1-vinylimidazole), poly (2-vinylpyrazine), poly (4-butenylpyridine), poly Examples include polymers containing (N, N-dimethylacrylamide), poly (N, N-dimethylaminopropylacrylamide) and polymers containing quaternary products thereof. Further, a polymer containing polyethyleneimine may be mentioned.

When using a water-soluble polymer among these polymers, it is preferable to add a cross-linking agent to the binder polymer solution and carry out the cross-linking treatment before use.

As the method for producing the porous ion exchanger of the present invention, the following method is preferable. That is, a method of heat-kneading the ion-exchange resin particles and the binder polymer to form a sheet by thermoforming such as a flat plate press, a method of applying a binder polymer solution to the ion-exchange resin particle surfaces and evaporating and curing the solvent, A method of extracting the pore-forming agent after heat-mixing and molding the binder polymer and the pore-forming agent and the ion-exchange resin particles, and applying a binder polymer solution in which the pore-forming agent is dispersed to the surface of the ion-exchange resin particles and curing it. For example, a method of extracting a pore forming agent.

Of these, a method of heat-kneading the ion-exchange resin particles and the binder polymer and then thermoforming such as a flat plate press, or a method of heating and mixing the binder polymer and the pore-forming agent and the ion-exchange resin particles to form the pore-forming agent The extraction method is preferable from the viewpoint of moldability and specific resistance of the resulting porous ion exchanger. In this case, it is preferable that the binder polymer is mixed in the form of particles having the same or smaller particle size than the ion exchange resin particles. The thermoforming temperature of the binder polymer is not particularly limited, and is preferably 120 to 180 ° C. from the viewpoint of heat resistance of the ion exchange resin particles.

When a pore-forming agent is used, it is preferable to add the pore-forming agent in an amount of 5 to 40% by weight based on the weight of the binder polymer. The type of pore-forming agent is not particularly limited, and any agent that can be extracted with a solvent later can be used, and polymer powders such as polyvinyl alcohol and polyester are preferable.

When a binder polymer solution is used,
The concentration is not particularly limited, and preferably 5 to 50% by weight. Usual organic solvents such as water, alcohols, ketones and esters are used as the solvent. In the method of coating the binder polymer solution on the surface of the ion-exchange resin particles and evaporating the solvent to cure, the ion-exchange resin particles are arranged on a mesh or a porous body as a support, and then the binder polymer solution is applied and dried. Alternatively, the ion-exchange resin particles may be dipped in the binder polymer solution, dried and then heated and pressed.

In the case of producing the above-mentioned porous ion exchanger having a layered structure or a sea-island structure, cation exchange resin particles and anion exchange resin particles are separately solidified by using a binder polymer to form a plate. For example, you can make small pieces by arranging them alternately, or punch holes of various shapes from the plate-shaped molded product, and then mold the plate-shaped product containing the other ion-exchange resin into it and fit it into it. The method can be adopted.

The porous ion exchanger of the present invention can be used in various devices for ion exchange when placed in a liquid flow path.
In particular, it can be preferably used in a method for continuously producing deionized water by filling a desalting chamber of an electrodialysis device in which cation exchange membranes and anion exchange membranes are alternately arranged.

As the method for producing deionized water, the following is specifically preferred. That is, a plurality of cation exchange membranes and anion exchange membranes are alternately arranged between an anode chamber having an anode and a cathode chamber having a cathode, and the anode side is partitioned by the anion exchange membrane and the cathode side is positive. Alternately, a desalting chamber partitioned by an ion-exchange membrane and a concentrating chamber partitioned by a cation-exchange membrane on the cathode side and an anion-exchange membrane on the anode side are alternately arranged.
About 30 sets are arranged in series. Desalination can be performed by flowing an electric current while flowing water to be treated in the desalting chamber and flowing water for discharging concentrated salts in the concentration chamber. It is preferable to apply a voltage of about 4 V, which causes water dissociation in the desalting chamber, to each unit cell.

When the porous ion exchanger of the present invention is arranged in the desalting chamber, deionized water can be produced by a so-called self-regenerating electrodialysis method. By forming the porous ion exchanger according to the size of the desalting chamber, it is possible to easily assemble the device in which the ion exchanger is filled in the desalting chamber. In the case of a usual electrodialysis device, the incorporated porous ion exchanger is plate-shaped. In the case of an electrodialyzer, the direction of current flow is perpendicular to the membrane surface, that is, in the thickness direction of the plate-shaped ion exchanger, and the water flow is perpendicular to it.

The thickness of the porous ion exchanger is the distance between the membranes in the desalting chamber, and is preferably 1 to 30 mm. 1mm thick
If it is smaller than the above range, the water in the desalting chamber may not flow easily and the amount of treated water may decrease, which is not preferable. If the thickness is larger than 30 mm, the electric resistance of the device may increase, which is not preferable. The thickness of the porous ion exchanger is 3-1
More preferably, it is 2 mm.

Since the ion-exchange resin particles sometimes swell when immersed in water, it is necessary to shape the porous ion-exchanger in consideration of the amount of swelling when incorporating it into an electrodialysis device or the like. On the contrary, the swelling can be used to bring the porous ion exchanger into close contact with the flow channel to prevent generation of unnecessary side flow. The same material as the binder polymer can be used to tightly bond the porous ion exchanger to the inside of the channel.

The porous ion exchanger of the present invention can also be used by arranging it in a flow path so that no current is passed when exchanging ions, and when desorbing adsorbed ions, an electric current is passed to regenerate it. At the time of regeneration, a porous ion exchanger is arranged between the anode and the cathode, and a diaphragm is arranged between the porous ion exchanger and the anode and the cathode to pass an electric current. The diaphragm does not have to be an ion exchange membrane, but for efficient regeneration, an anion exchange membrane is placed on the anode side and a cation exchange membrane is placed on the cathode side of the porous ion exchanger. Is preferred.

[0041]

【Example】

Example 1 Sulfonic acid type cation exchange resin having a particle size of 400 to 550 μm and an ion exchange capacity of 4.2 meq / g dry resin (Rohm and Haas Co., trade name Amberlite 20)
1CT), and a quaternary ammonium salt type anion exchange resin having a particle size of 400 to 530 μm and an ion exchange capacity of 3.7 meq / g dry resin (Rohm and Haas Co., product name Amberlite IRA400) after drying. , Cation exchange resin / anion exchange resin = 50/50 (volume ratio in the dry state) to obtain a mixture having an ion exchange volume ratio of 60/40.

A linear low-density polyethylene pellet (trade name: Affinity SM, manufactured by Dow Chemical Co., Ltd.) was added to this mixture.
-1300) was mixed at 3% by weight and kneaded at 120 to 130 ° C. The obtained kneaded product was thermoformed at 130 ° C. by a flat plate press and cut into a rectangular parallelepiped of 0.8 cm × 13 cm × 40 cm to obtain a porous ion exchanger.

0.8 cm × 1 of this porous ion exchanger
Water permeability between 3 cm surface is 0.35 kg / cm ² pressure.
At 150 kg · cm ⁻¹ · h ⁻¹ , the porosity of the voids opened to the outside was 23% by volume. In addition, this porous ion exchanger was placed in a cell partitioned by two sheets of ion-exchange resin, and filled with water having an electric conductivity of 10 μS / cm, and an electric current was passed. When the current density was 0.005 A / cm ^2, the specific resistance was 390 Ω · cm, and a value lower than 680 Ω · cm when the same measurement was performed by filling the same cell with the ion exchange resin having the same mixing ratio was obtained.

This porous ion exchanger was incorporated into a desalting chamber of an electrodialyzer and a water treatment test was conducted. As the electrodialysis device, a cation exchange membrane (made by Asahi Glass Co., Ltd., trade name Selemion CMT) and an anion exchange membrane (made by Asahi Glass Co., Ltd., trade name Selemion AMP) having an effective area of 500 cm ² × 5 pairs were used. When water having an electric conductivity of 5 μS / cm was used as raw water and desalting was performed by applying a voltage of 4 V per unit cell, treated water having an electric conductivity of 0.07 μS / cm was stably obtained.

Example 2 After drying the same cation exchange resin and anion exchange resin as in Example 1, cation exchange resin / anion exchange resin = 50 /
The mixture was mixed at 50 (volume ratio in a dry state) to obtain a mixture having an ion exchange volume ratio of 60/40. The ion-exchange resin mixture was placed on a 100-mesh polyester cloth, a toluene solution of 50% nitrile rubber was applied as a binder polymer solution, and then dried at 60 ° C. for 2 hours. 0.8 for this
It was cut into a rectangular parallelepiped having a size of cm × 13 cm × 40 cm to obtain a porous ion exchanger. The weight ratio of the binder polymer to the ion exchange resin used was 5/95, which was determined from the weight increase.

The water permeability of the obtained porous ion exchanger is 130 kg · cm ^{−1 at a} pressure of 0.35 kg / cm ² .
-H ^-1 , the porosity of the voids opened to the outside was 25% by volume. The specific resistance measured in the same manner as in Example 1 is 620.
In Ω · cm, a value lower than 680 Ω · cm when the ion exchange resin having the same mixing ratio was put into the cell and measured.

This porous ion exchanger was incorporated into a desalting chamber of an electrodialyzer to carry out a water treatment test. As the electrodialysis device, a cation exchange membrane (made by Asahi Glass Co., Ltd., trade name Selemion CMT) and an anion exchange membrane (made by Asahi Glass Co., Ltd., trade name Selemion AMP) having an effective area of 500 cm ² × 5 pairs were used. When water having an electric conductivity of 5 μS / cm was used as raw water to apply desalting by applying a voltage of 4 V per unit cell, treated water having an electric conductivity of 0.09 μS / cm was stably obtained.

Example 3 After drying the same cation exchange resin and anion exchange resin as in Example 1, cation exchange resin / anion exchange resin = 35 /
The mixture was mixed at a ratio of 65 (volume ratio in a dry state) to give a mixture having an ion exchange volume ratio of 45/55. This mixture was placed on a 100-mesh polyester cloth, and a 5% acrylic acid aqueous solution containing 0.2% of blocked isocyanate (Takeda Pharmaceutical Co., Ltd., trade name Prominate XC) was applied as a binder polymer solution. The drying for 30 minutes was repeated 3 times. Finally, thermal crosslinking treatment was carried out at 150 ° C. for 10 minutes, and this was cut into a rectangular parallelepiped of 0.3 cm × 13 cm × 40 cm to obtain a porous ion exchanger. The weight ratio of the binder polymer to the ion exchange resin used was 15/85, which was determined from the weight increase.

The water permeability of this porous ion exchanger is 180 kg · cm ⁻¹ · h at a pressure of 0.35 kg / cm ² .
^-1 , The porosity of the continuous voids was 45% by volume. The specific resistance measured in the same manner as in Example 1 is 650 Ω · cm.
Then, a value lower than 680 Ω · cm when the ion exchange resin having the same mixing ratio was put into the cell for measurement was obtained.

This porous ion exchanger was incorporated into a desalting chamber of an electrodialyzer for water treatment test. As the electrodialysis device, a cation exchange membrane (made by Asahi Glass Co., Ltd., trade name Selemion CMT) and an anion exchange membrane (made by Asahi Glass Co., Ltd., trade name Selemion AMP) having an effective area of 500 cm ² × 5 pairs were used. When water having an electric conductivity of 5 μS / cm was used as raw water to apply desalting by applying a voltage of 4 V per unit cell, treated water having an electric conductivity of 0.12 μS / cm was stably obtained.

Example 4 0.2 mol tetrafluoroethylene and 0.045 mol CF ₂ = starting with azobisisobutyronitrile
CFOCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ SO ₂ F was copolymerized under the conditions of a polymerization temperature of 70 ° C. and a polymerization time of 5 hours to obtain a copolymer having an ion exchange capacity of 1.1 meq / g. Got This was hydrolyzed in a 20% KOH aqueous solution at 90 ° C. for 16 hours, immersed in 1N hydrochloric acid at room temperature for 16 hours to be converted into an acid form, and dissolved in ethanol to dissolve perfluorosulfone having a concentration of 8%. An acid polymer solution was obtained.

A mixture of ion-exchange resin particles obtained in the same manner as in Example 1 was arranged on a 100-mesh polyester cloth,
The above 8% perfluorosulfonic acid polymer solution was applied as a binder polymer solution and then dried at 50 ° C. for 30 minutes, which was repeated 3 times. 0.3 cm x 13 cm x
It was cut into a 40 cm rectangular parallelepiped to obtain a porous ion exchanger. The weight ratio of the binder polymer and the ion exchange resin used, which was determined from the weight increase, was 20/80.

The water permeability of the obtained porous sheet material is 160 kg · cm ⁻¹ · at a pressure of 0.35 kg / cm ² .
The porosity of h ⁻¹ and continuous voids was 40% by volume. Further, when the value of the specific resistance in water of 10 μS / cm was put in the cell and measured, it was 580 Ω · cm at a current density of 0.005 A / cm ² , and the ion exchange resin having the same mixing ratio was put in the cell for measurement. A value lower than 680 Ω · cm was obtained.

This porous ion exchanger was placed in a desalting chamber,
A water treatment test was conducted in the same manner as in Example 1. Conductivity 5 as raw water
When desalting was performed by applying a voltage of 4 V per unit cell using water of μS / cm, the conductivity was 0.07 μS / cm.
cm of treated water was stably obtained. This performance has been stable for one month.

[0055]

INDUSTRIAL APPLICABILITY The porous ion exchanger of the present invention has high mechanical strength of the ion exchanger and excellent ion exchange performance, so that treated water with stable purity can be obtained. Since the ion exchanger obtained by this method is in the form of a sheet, it is easy to handle, and since complicated steps are not required for the production, it is possible to easily obtain stable performance.

The method for producing deionized water of the present invention can continuously produce high-purity deionized water stably for a long period of time. In addition, since the porous ion exchanger is used, the electrodialysis device can be easily assembled.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C02F 1/469 C02F 1/46 103 (72) Inventor Ken Komatsu 1150 Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Address Asahi Glass Co., Ltd. Central Research Institute (72) Inventor Kazuo Umemura 1150 Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Company Central Research Institute

Claims (10)

[Claims] 1. A porous structure in which ion-exchange resin particles are bonded using a binder polymer, and the pressure is 0.35 kg / c.
A porous ion exchanger having a water permeability of 30 kg · cm ⁻¹ · h ⁻¹ or more at m ² . 2. The porous ion exchanger according to claim 1, wherein the voids open to the outside have a porosity of 5 to 50% by volume. 3. The porous ion exchanger according to claim 1, wherein the ion exchange resin particles are cation exchange resin particles or anion exchange resin particles or a mixture of cation exchange resin particles and anion exchange resin particles. . 4. The specific resistance when the porous ion exchanger is placed in the desalting chamber of the electrodialysis device is the same as the specific resistance when only the ion exchange resin particles contained therein are filled in the same desalting chamber. The porous ion exchanger according to any one of claims 1 to 3, which has a value of 2 times or less. 5. The porous ion exchanger according to claim 1, wherein the binder polymer is a polymer containing an ion exchange group or a group convertible to an ion exchange group. 6. The porous ion exchanger according to claim 1, wherein the binder polymer is a thermoplastic polymer or a solvent-soluble polymer. 7. A method for producing a porous ion exchanger according to any one of claims 1 to 5 by mixing the ion exchange resin particles with a binder polymer and then heat-molding the mixture. 8. The method according to claim 1, wherein the ion exchange resin particles are mixed with the binder polymer solution and then the solvent is removed.
A method for producing any one of the porous ion exchangers. 9. A deionized water producing apparatus comprising a deionized water production apparatus having an ion exchanger housed in a desalting chamber of an electrodialysis apparatus in which cation exchange membranes and anion exchange membranes are alternately arranged between a cathode and an anode. A method for producing deionized water by energizing while flowing water to be treated into a salt chamber, wherein the porous ion exchanger according to claim 1 is used as the ion exchanger. . 10. A porous ion exchanger according to any one of claims 1 to 6 is disposed between a cathode and an anode, and a diaphragm is disposed between each of the ion exchanger and the cathode and the anode to conduct electricity. A method for regenerating an ion exchanger in which the ions adsorbed on the ion exchanger are desorbed.