JPH11300364A - Electric deionized water producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrically deionized water producing device a nonwaven mat to which innumerable fine grains of ion-exchange resin are adhered as a component member, with the deionization module easily assembled, with the entire device made compact and capable of being produced at a low cost. SOLUTION: An electric deionized water producing device 10 is obtained by alternately arranging a cation-exchange membrane 11 and an anion-exchange membrane 12 between an anode 20 and a cathode 19 and alternately forming a desalting chamber 14 and a concentration chamber 15 between both membranes. In this case, a nonwaven mat 13 to which innumerable ion-exchange resin fine grains are adhered is inserted in a desalting chamber 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric deionized water producing apparatus used in various industries, such as a semiconductor manufacturing industry, a pharmaceutical industry, a food industry, etc., or a power plant, a research laboratory, etc. using deionized water. It is.

[0002]

2. Description of the Related Art Conventionally, an electric deionized water producing apparatus which has been put to practical use basically has a particle diameter of 0.5 to 3 mm as an ion exchanger in a gap formed by a cation exchange membrane and an anion exchange membrane. A granular ion-exchange resin or ion-exchange fiber to form a desalination chamber, pass the water to be treated through the ion-exchanger, and apply a direct current through the both ion-exchange membranes; The deionized water is produced while electrically removing ions in the water to be treated from the concentrated water flowing outside the container.

FIG. 3 is a schematic sectional view of a typical conventional electric deionized water producing apparatus. As shown in FIG. 3, the cation exchange membrane 101 and the anion exchange membrane 102 are alternately arranged at a distance from each other, and the cation exchange resin and the anion exchange membrane are alternately arranged in a space formed by the cation exchange membrane 101 and the anion exchange membrane 102. A deionization chamber 104 is formed by filling a mixed ion exchange resin 103 of the exchange resin. Further, a portion not adjacent to each of the desalting chambers 104 filled with the mixed ion exchange resin 103 formed by the anion exchange membrane 102 and the cation exchange membrane 101 is a concentration chamber 105 for flowing concentrated water.
And

As shown in FIG. 4, a deionization module 10 is composed of a cation exchange membrane 101, an anion exchange membrane 102, and a granular mixed ion exchange resin filled therein.
6 is formed. That is, the assembly of the deionization module 106 is performed in a wet state in order to avoid cracks and deformation of the mixed ion exchange resin. Specifically, the cation exchange membrane 101 is provided on one side of the frame 107 whose inside is hollowed out. After sealing, the hollow portion of the frame 107 is filled with a mixed ion exchange resin, and then the other portion of the frame 107 is sealed with an anion exchange membrane 102 using an adhesive or the like to form a so-called sandwich. It is performed by forming. In the drawing, reference numeral 108 denotes a rib.

The particle size of the granular mixed ion exchange resin is usually in the range of about 0.5 to 3 mm. This is because if the fine particle size is small, the pressure difference in water passage is high and it cannot withstand practical use, and if the large particle size is used, the space between the particles is widened when filled and the ion removal efficiency is deteriorated. .

FIG. 3 shows a state in which a plurality of such deionization modules 106 are arranged side by side with a spacer (not shown) interposed therebetween. And an anode 110 is provided on the other end side. The enrichment chamber 105 is located between the above-described spacers, and a partition membrane 111 such as a cation exchange membrane, an anion exchange membrane, or a simple membrane having no ion exchange properties is provided on both outer sides of the enrichment chamber 105 at both ends as necessary. And the partition membrane 111
The portions where the two electrodes 109 and 110 contact each other are referred to as a cathode chamber 112 and an anode chamber 113, respectively. When the water to be treated is passed through such an electric deionized water producing apparatus, impurity ions in the water to be treated are electrically removed, so that the filled ion exchange resin is not regenerated by a chemical solution at all. Deionized water can be obtained continuously.

[0007]

However, the conventional electric deionized water producing apparatus has a complicated structure and requires considerable time and labor for production. In particular, when assembling a deionization module that forms a desalination chamber, it is necessary to uniformly fill the wet ion-exchange resin while laminating and bonding a plurality of sandwich-shaped ends using an adhesive. Requires considerable skill and is difficult to automate. Even when an adhesive is not used, it is difficult to handle a wet ion exchange resin. In order to solve these problems, there is an ion-exchange fiber which is used in the form of a sheet or mat and is inserted into a desalting chamber. However, in this case, there is a problem that the fiber must always be handled in a wet state.

An ion exchanger such as a granular ion exchange resin or an ion exchange fiber may be charged not only in a desalting chamber but also in a concentration chamber and an electrode chamber. In this case, the ion exchanger used in the concentration chamber and the electrode chamber is different from the ion exchanger used in the desalination chamber where the filling rate of the ion exchanger is high, and reduces the voltage between the electrodes, and a hardness component accumulated by passing water, In order to avoid an increase in the differential pressure due to silica or the like, a low filling rate, that is, a high porosity is required. Therefore, in order to provide an ion exchanger having an optimum exchange capacity and a filling rate for the desalting chamber, the concentrating chamber, and the electrode chamber having different required performances, it is desired to develop an ion exchanger in which the porosity can be easily controlled. I was

Accordingly, an object of the present invention is to provide an ion exchanger in which the porosity can be easily controlled, to easily assemble a deionization module using the ion exchanger as a constituent member, and to make the entire apparatus compact. An object of the present invention is to provide an electric deionized water producing apparatus which can be produced at low cost.

[0010]

Under such circumstances, the present inventors have conducted intensive studies and as a result, have found that a granular ion-exchange resin or an ion-exchange resin used in a desalination chamber or the like of a conventional electric deionized water producing apparatus. If, instead of the exchange fibers, a countless number of fine particle ion exchange resins attached to a nonwoven fabric mat that does not have ion exchange capability by itself is used, (1) an increase in particle surface area increases the ion exchange rate, The whole device can be made compact. (2) The deionization module is extremely easy to assemble because the assembly is in a dry state and the components can be handled as solids. (3) The porosity can be easily controlled because a nonwoven fabric mat is used. (4) The fine particle ion exchange resin can be manufactured by physically crushing the conventionally used granular ion exchange resin, and the nonwoven fabric mat can be manufactured at a low cost because an inexpensive commercial product can be used. As a result, the present invention has been completed.

That is, the present invention provides an electric deionized water production system in which a cation exchange membrane and an anion exchange membrane are alternately arranged between an anode and a cathode, and a desalination chamber and a concentration chamber are alternately formed between both membranes. It is an object of the present invention to provide an electric deionized water producing apparatus in which a nonwoven fabric mat having a myriad of particulate ion exchange resins attached thereto is inserted into at least a desalting chamber.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The electric deionized water producing apparatus according to the present invention is a nonwoven fabric in which a myriad of particulate ion-exchange resins are adhered to at least a desalination chamber, preferably a desalination chamber, a concentration chamber and an electrode chamber. A mat is inserted. As the particulate ion exchange resin, a conventional particle size of about 0.5 to 3
Fine particle ion exchange resin obtained by physically crushing a granular ion exchange resin of mm, after manufacturing a resin matrix of fine particles, and those into which ion exchange groups are introduced, and the like.
Among them, the particulate ion exchange resin obtained by physical crushing is preferable because it can be obtained at low cost.

The fine particle means fine particles, powder, etc.
Although the particle diameter is not particularly limited, it is about several hundred μm or less, preferably several tens μm or less, as a single particle diameter.

The particulate ion exchange resin is not particularly limited, but is preferably a mixed resin of a particulate anion exchange resin and a particulate cation exchange resin.

As the nonwoven fabric mat to which the particulate ion exchange resin is adhered, a web is formed by using fibers,
The web is subjected to a heat bonding method using a hot roll, a hot air passing device, a mechanical bonding method using a needle punch, a water jet punch or the like, or a chemical bonding method using a solvent resistant resin such as PVA or epoxy resin. After being subjected to a primary bonding treatment, it is obtained by performing a drying treatment, and is formed by bonding and fixing between the constituent fibers of the web. On the surface and inside, there are countless voids (porosity) between the entangled fibers. It has.

The method for forming the web is not particularly limited, and a web obtained by a dry method using a card, a land webber, or the like; a web obtained by direct spinning such as melt blown or spun bond; short fibers in water And a web obtained by a wet method of dispersing and making paper. Examples of the fibers forming the web include organic fibers, and among them, olefin fibers are preferably used for part or all.
Examples of the olefin-based fiber include polyethylene fiber and polypropylene fiber, among which split fibers composed of polypropylene and polyethylene; core-sheath type fiber whose core is polypropylene and sheath is polyethylene; porous type polyethylene or polypropylene Fibers and the like can be used. These fibers themselves do not have an ion exchange ability, but those having corrosion resistance are particularly preferred.

The size of the internal voids (openings) is much larger than the particle size of the fine particle ion exchange resin.
It is about 5 to 2 mm, its shape is not specified, and it is indefinite. In the case where the nonwoven fabric mat is used in a desalting chamber, the aperture is appropriately determined in view of securing a flow path for the water to be treated and deionization efficiency. In addition, when used in the concentration chamber and the electrode chamber, it is appropriately determined from the viewpoint of suppressing the increase in the differential pressure due to the hardness component and silica or the like accumulated by passing water and reducing the voltage between the electrodes. The size of the voids is adjusted during the production of the nonwoven fabric mat at the stage of forming a web using constituent fibers having a required fiber diameter, by adjusting the amount of spun fibers to adjust the basis weight, and by adjusting the amount of resin and / or By adjusting the number of punches, the number of punches can be easily adjusted, and a desired porosity can be easily obtained.

The porosity of the nonwoven fabric mat can be easily adjusted by appropriately changing the type of fiber, the basis weight and the thickness of the nonwoven fabric mat, and can be calculated from the following equations (1) and (2). . Apparent specific gravity of the mat G (g / cm ³ ) = W / 1000 × t (1) Porosity P% = (SG) / S × 100 (2) In the formula (1), W is the mass (g) of the mat. / m ² ), and t indicates the thickness (mm) of the product. In the formula (2), S indicates the specific gravity of the constituent fiber. In the above formula, the apparent specific gravity of the mat can be replaced by the apparent density of the mat (g / cm ³ ), and the mass of the mat can be replaced by the basis weight of the mat (g / m ² ).

When the particulate ion exchange resin adheres to the nonwoven fabric fiber mat, the cation exchange membrane and the anion exchange membrane are electrically connected via the particulate ion exchange resin so that the ions can be removed by energization. In other words, a particulate ion exchange resin is adhered to the surface and inside of the nonwoven fabric mat so that a good conductor can be formed. The adhesion is not particularly limited, and a physical adhesion method, a chemical adhesion method using an adhesive, or the like can be used.

As a method for adhering the particulate ion exchange resin to the nonwoven fabric fiber mat using an adhesive, a secondary bonding treatment appropriately selected from a spray method, a dipping method, a coating method and the like can be applied. For example, a particulate ion exchange resin is dispersed in a solution in which a thermoplastic elastomer adhesive (binder resin) is dissolved in an organic solvent to form a slurry, and the slurry and the nonwoven fabric mat are secondarily bonded by a dipping method. After the treatment, a drying treatment is performed. Thereby, on the constituent fiber surface and fiber entangled part of the nonwoven fabric mat,
A composition in which fibers are firmly fixed together by coating with a predetermined amount of adhesive is obtained. In this composition, fine narrow grooves (or voids) are formed by an organic solvent on the surface of the olefin-based fiber which is a constituent fiber of the nonwoven fabric mat, and the adhesive infiltrates into the narrow grooves to firmly adhere to the fine particles. The ion exchange resin is also firmly fixed with this adhesive in a state that at least a part of the fiber surface part and the fiber entangled part has an exposed part, and most of the particulate ion exchange resin is attached to a part of the surface. It is firmly fixed with the exposed portion.

Examples of the adhesive include a styrene-based thermoplastic copolymer; an olefin-based adhesive such as a polypropylene resin or a polyethylene resin; and a halogenated polyolefin-based adhesive such as a polytetrafluoroethylene resin. Alternatively, two or more kinds can be used in combination. In particular, when a styrene-butadiene-styrene (SBS) -based or styrene-ethylene-butylene-styrene (SEBS) -based styrene-based copolymer is partially or entirely used, olefin-based fibers and particulate ion exchange It is preferable because of excellent adhesiveness with the resin. Examples of the organic solvent include xylene, toluene, methylcyclohexane, and tetrahydronaphthalene, and these can be used alone or in combination of two or more. Further, when a fine-particle ion exchange resin having a shape having fine pores (voids) on its surface is used, the resin is fixed with an adhesive and has an anchor effect, and is covered with an increase in surface area. It is preferable because the ion exchange ability can be sufficiently exhibited in the treated water. Further, the amount of adhesion can be adjusted by appropriately selecting the mixing weight ratio with the adhesive.

In the present invention, as shown in FIG. 1, for example, the deionization module forming the desalting chamber includes a cation exchange membrane 11 and an anion exchange membrane 12, and a myriad of fine particle ion exchange resins inserted therein. It is formed with the nonwoven fabric mat 13 attached. In FIG. 1, nonwoven fabric fiber mat 1
Although the surface of No. 3 has fine particles attached thereto, it is shown in a mesh pattern for convenience. Further, the deionization module may be assembled in a dry state, and each component may be handled as a solid. Further, as the form of the deionization module, since the nonwoven fabric mat is flexible, various forms can be adopted. For example, a spiral form can be adopted.

FIG. 2 is a schematic sectional view of an electric deionized water producing apparatus according to an embodiment of the present invention, in which a nonwoven fabric mat 13 is inserted only in a desalting chamber. FIG.
As shown in (1), the cation exchange membranes 11 and the anion exchange membranes 12 are alternately arranged at a distance from each other, and the ion exchange resin in the form of fine particles is alternately placed in the space formed by the cation exchange membranes 11 and the anion exchange membranes 12. The attached nonwoven fabric mat 13 is inserted into the desalting chamber 14. Further, the anion exchange membrane 12 and the cation exchange membrane 1 located next to the desalting chamber 14 respectively.
The portion where the nonwoven fabric mat 13 formed in 1 is not inserted is a concentration chamber 15 for flowing concentrated water.

FIG. 2 shows a state in which a plurality of deionization modules 16 are arranged side by side with a spacer (not shown) interposed therebetween, and a cathode 19 is disposed at one end of the side-by-side deionization modules 16. And an anode 2 on the other end.
0 is arranged. The enrichment chamber 15 is located at the position sandwiching the above-mentioned spacers, and a partition membrane 21 such as a cation exchange membrane, an anion exchange membrane, or a mere diaphragm having no ion exchange properties is provided on both outer sides of the enrichment chambers 15 at both ends as necessary. The portions where the two electrodes 19 and 20 are separated from each other by the partition film 21 are referred to as a cathode chamber 22 and an anode chamber 23, respectively.

When producing deionized water by such an electric deionized water producing apparatus, the following operation is performed. That is, a direct current flows between the cathode 19 and the anode 20, and the water to be treated flows in from the water inlet A, the concentrated water flows in from the concentrated water inlet B, and the electrode water flows from the electrode water inlets C and D, respectively. Flows in. The water to be treated flowing from the treated water inlet A flows into each desalting chamber 14 as shown by the solid line arrow,
The impurity ions are removed when flowing down the void portion and passing through the attachment portion of the particulate ion exchange resin, and deionized water is obtained from the deionized water outlet a. The concentrated water flowing from the concentrated water inlet B flows down each concentration chamber 15 as shown by the dotted arrow, receives impurity ions moving through both ion exchange membranes, and concentrates the impurity ions. The electrode water flowing out from the concentrated water outlet b and flowing from the electrode water inlets C and D is further discharged from the electrode water outlets c and d.
Spilled out of.

According to the electric deionized water producing apparatus in the above embodiment, impurity ions in the water to be treated are electrically removed by the above-described operation. Deionized water can be continuously obtained at the same deionization rate, and the apparatus can be made compact.

Further, in the electric deionized water producing apparatus of the present invention, a nonwoven fabric mat to which the fine particle ion exchange resin is adhered can be inserted into the concentration chamber and the electrode chamber. In this case, the nonwoven fabric mat to be inserted preferably has a larger opening than that inserted into the desalting chamber. As a result, it is possible to avoid an increase in the differential pressure due to the hardness component, silica, turbidity, etc. accumulated by the flow of water, and to reduce the voltage between the electrodes. Can be.

[0028]

Next, the present invention will be described in more detail with reference to examples, but this is merely an example and does not limit the present invention. Example 1 (Manufacture of nonwoven fabric mat to which particulate ion exchange resin was attached) Using the following nonwoven fabric mat, adhesive and particulate ion exchange resin, an ion exchanger was produced according to the above-mentioned bonding method.・ Nonwoven fabric mat; length 400mm, width 120mm, thickness 6mm,
Porosity 94% (polypropylene fiber 15d, 100%,
・ Kanai Important Industry Co., Ltd.) ・ Particulate ion exchange resin; commercial product Amberlite IR-1
20B and IRA-402BL (manufactured by Rohm and Haas) are crushed and classified and have an average particle diameter of 45 μm. Ion exchange resin ・ Adhesive; SEBS resin (manufactured by Shell)

When the nonwoven fabric mat obtained above was charged into a desalting chamber as shown in FIG. 2 and operated, good deionized water was obtained.

[0030]

According to the present invention, a myriad of ion-exchange resins in the form of fine particles are replaced with non-woven fabrics in place of the granular ion-exchange resin or the ion-exchange fiber used in the desalination chamber of the conventional electric deionized water production apparatus. In order to use what is attached to the mat,
(1) Since the ion exchange rate is increased by increasing the particle surface area,
The whole device can be made compact. (2) The deionization module is extremely easy to assemble because the assembly is in a dry state and the components can be handled as solids. (3) The use of a non-woven mat makes it easy to control the porosity,
It can be manufactured according to applications such as those having a high exchange capacity or those capable of suppressing an increase in differential pressure. (4) The particulate ion exchange resin can be produced by physically crushing the conventionally used granular ion exchange resin, and the nonwoven fabric mat can be manufactured at low cost because an inexpensive commercial product can be used. (5) Make the deionization module a spiral form,
If this is loaded into a cylindrical pressure-resistant container and the periphery of the pressure-resistant container and the center of the spiral are used as electrodes, an electric deionized water production device with improved pressure-resistant performance can be obtained. The degree of freedom of the configuration is significantly increased as compared with the ion water production apparatus.

[Brief description of the drawings]

FIG. 1 is an assembly view of a deionization module used in the electric deionized water production apparatus of the present invention.

FIG. 2 is a schematic cross-sectional view of an electric deionized water producing apparatus according to an embodiment of the present invention.

FIG. 3 shows a schematic cross-sectional view of a conventional electric deionized water producing apparatus.

FIG. 4 is an assembly view of a deionization module used in a conventional electric deionized water producing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Electric deionized water production apparatus 11, 101 Cation exchange membrane 12, 102 Anion exchange membrane 13 Nonwoven fabric mat to which particulate ion exchange resin was attached 14, 104 Deionization chamber 15, 105 Concentration chamber 16, 106 Deionization module 19, 109 Cathode 20, 120 Anode 21, 111 Partition membrane 22, 112 Cathode chamber 23, 113 Anode chamber 103 Granular mixed ion exchange resin 107 Frame 108 Rib A Water inlet for treated water B Concentrated water inlet C, D Electrode water inlet a Desorption Ion water outlet b Concentrated water outlet c, d Electrode water outlet

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Masahiko Miyoshi 5-2-1 Karigaoka, Hirakata-shi, Osaka C16-108

Claims (3)

[Claims] 1. An electric deionized water producing apparatus comprising a cation exchange membrane and an anion exchange membrane alternately arranged between an anode and a cathode, and a desalination chamber and a concentration chamber alternately formed between both membranes. An electric deionized water production apparatus in which a nonwoven fabric mat having a myriad of fine particle ion exchange resins attached thereto is inserted into a deionization chamber. 2. A method in which a fine ion exchange resin is attached to the surface and inside of a nonwoven fabric mat so that a cation exchange membrane and an anion exchange membrane can form a good conductor through a fine ion exchange resin. The electric deionized water producing apparatus according to claim 1. 3. The apparatus for producing deionized water according to claim 1, wherein the particulate ion exchange resin is a mixed resin of a particulate cation exchange resin and a particulate anion exchange resin.