JP5282860B2 - Electrodeionization equipment - Google Patents

Abstract

Provided is an electric deionization apparatus using a filler material having a function and strength equal to or higher than those of an ion-exchange resin that is conventionally filled in the demineralization chambers and/or the concentration chambers of the electric deionization apparatus and also having ion conductivity. The electric deionization apparatus (1) is constituted by arranging anion-exchange membranes (5) and cation-exchange membranes (4) between a cathode (6) and an anode (7) to form the demineralization chambers (2) and the concentration chambers (3). The demineralization chambers (2) and/or the concentration chambers (3) are filled with a foam body (8) of a continuous bubble structure for holding a fine ion-exchange body.

Description

  The present invention relates to an electrodeionization apparatus in which a plurality of anion exchange membranes and cation exchange membranes are alternately arranged between a cathode and an anode to alternately form a concentration chamber and a desalting chamber.

  Conventionally, for the production of deionized water used in various industries such as semiconductor manufacturing factory, liquid crystal manufacturing factory, pharmaceutical industry, food industry, electric power industry, etc. A plurality of anion exchange membranes and cation exchange membranes are arranged to form a concentrating chamber and a desalting chamber, and the anion exchanger and cation exchanger comprising an ion exchange resin, ion exchange fiber or graft exchanger in the desalting chamber Electrodeionization devices that are mixed or filled in a multilayer are often used.

Electrodeionization equipment enables efficient desalination by generating H ⁺ ions and OH ⁻ ions by water dissociation and continuously regenerating the ion exchanger filled in the desalting chamber. Unlike conventional ion exchange resin devices that have been widely used, there is no need for regeneration treatment using chemicals, and complete continuous water collection is possible, resulting in high-purity water. It is effective.

  Conventionally, materials such as ion exchange resins have been proposed as ion exchangers filled in the demineralization chamber and / or the concentration chamber of such an electrodeionization apparatus (see Patent Document 1).

  When an ion exchange resin is used as the ion exchanger filled in the desalting chamber and / or the concentration chamber, the density of the ion exchange groups can be increased, and the cation exchange resin and the anion exchange resin can be mixed at an arbitrary ratio. At present, ion exchange resins are generally used as fillers. However, the work of closely filling the ion-exchange resin into the desalting chamber in order to prevent a short circuit of the water to be treated in the desalting chamber is very complicated, and the water-flowing is performed because the ion-exchange resin is closely packed. There was a problem that the differential pressure was high and the ion exchange resin was easily crushed due to deterioration or the like.

In order to solve such problems, conventionally, as an ion exchanger that replaces an ion exchange resin, an ion exchange fiber, a graft exchanger, a porous material synthesized through w / o emulsion formation and stationary polymerization are used. A filler in which an ion exchange group is introduced into a porous resin has been proposed (see Patent Documents 2 to 6).
Japanese Patent No. 1782943 Japanese Patent No. 2751090 Japanese Patent No. 2699256 Japanese Patent No. 3773190 Japanese Patent No. 3781361 Japanese Patent No. 3856387

  However, when the ion exchange fiber described in Patent Document 2 is used as an ion exchanger of an electrodeionization apparatus, although an improvement in ion movement speed is expected compared with an ion exchange resin, There is a problem that ions are likely to leak into the treated water due to a short circuit of the treated water, and it is difficult to obtain high-purity treated water.

  Moreover, the filler which introduce | transduced the ion exchange group into the porous resin described in the said patent documents 4-6 has a problem that manufacturing cost is high and is unsuitable for the synthesis | combination and mass production of the magnitude | size of a practical use level. There is.

  In view of such a situation, the present invention has functions and strengths equal to or higher than those of ion exchange resins that have been conventionally filled in a demineralization chamber and / or a concentration chamber of an electrodeionization apparatus, and an ion An object of the present invention is to provide an electrodeionization apparatus using a conductive filler.

In order to solve the above-described problems, the present invention provides an electrodeionization apparatus in which a plurality of anion exchange membranes and cation exchange membranes are arranged between a cathode and an anode to form a desalting chamber and a concentration chamber. An electrodeionization apparatus is provided, wherein the demineralization chamber and / or the concentration chamber is filled with a foam having an open cell structure for holding a fine ion exchanger ( invention). 1).

According to the above invention ( Invention 1), the demineralization chamber and / or the concentration chamber of the electrodeionization apparatus is filled with the foam having an open cell structure in which the fine ion exchanger is held. The treated water supplied to the chamber can pass through the pores of the foam, preventing a short circuit of the treated water in the desalting chamber and reducing the water flow differential pressure in the desalting chamber. it can. In addition, since the water to be treated and the fine ion exchanger held in the foam can be effectively contacted, ion leakage to the treated water can be prevented, and high-purity treated water can be obtained. Can be obtained.

In the said invention ( invention 1), it is preferable that the said ion exchanger is an anion exchanger and a cation exchanger ( invention 2), and in this invention ( invention 2), the said anion hold | maintained at the said foam The volume ratio of the exchanger to the cation exchanger may be 1: 9 to 9: 1 ( Invention 3).

According to the above inventions ( Inventions 2 and 3), the desalting chamber and / or the concentrating chamber is filled with the foam holding the anion exchanger and the cation exchanger, so that the covering in the desalting chamber can be performed. The movement of the anion and cation in the treated water can be promoted, and a treated water with higher purity can be obtained.

In the said invention ( invention 1-3), the ion exchange group density in the contact surface of the said foam which contacts the said anion exchange membrane or the said cation exchange membrane is more than the ion exchange group density in the other site | part of the said foam. Preferably, it is high ( Invention 4). In the invention ( Invention 4), a plurality of irregularities are formed on the contact surface of the foam, and the foam has the ion exchanger on the contact surface. Is preferably further fixed ( Invention 5).

According to the said invention ( invention 4), the ion-exchange group density in the contact surface of the foam which contacts an anion exchange membrane and a cation exchange membrane is high, and can accelerate | stimulate the movement of the anion and cation in to-be-processed water more. It is possible to obtain treated water with higher purity. In particular, as in the above invention ( Invention 5), by forming a plurality of uneven portions on the contact surface of the foam, the surface area of the contact surface can be increased, and the ion exchanger is further fixed to the uneven portion. By making it, the ion exchange group density in a contact surface can be made higher density.

In the said invention ( invention 1-5), the said ion exchanger contains an ion exchange resin at least, The average particle diameter of the said ion exchange resin is 100 micrometers or less, and the ion exchange resin whose particle diameter is 200 micrometers or less is 90. preferably contains by mass% or more (invention 6), also the ion exchanger comprises at least ion-exchange fibers, the average fiber length of the ion-exchange fibers, and at 2.5mm or less, a fiber length of 5.0mm It is preferable that 90% or more of the following ion exchange fibers are contained ( Invention 7).

According to the above inventions ( Inventions 6 and 7), the particle diameter of the ion exchange resin is within the above range, or the fiber length of the ion exchange fiber is within the above range, so that the water to be treated is more effectively treated. An ion exchange resin or an ion exchange fiber can be contacted.

In the said invention ( invention 1-7), it is preferable that the said foam is formed by adding the said ion exchanger of 20-80 mass% with respect to a foaming agent to the said foaming agent ( invention 8). In this invention ( Invention 8), the foam is formed by adding 20 to 80% by mass of the ion exchanger to the matrix resin with respect to the matrix resin constituting the foam. Preferred ( Invention 9). In the invention ( Invention 9), an ion exchange group may be introduced into the molecular chain of the matrix resin ( Invention 10).

In the above inventions ( Inventions 9 and 10), the matrix resin is at least one of acrylate resin, acrylate rubber, natural rubber, butyl rubber, polyisoprene, polychloroprene, styrene-butadiene rubber, and nitrile rubber. It is preferable to contain 5-50 mass% ( Invention 11).

According to the said invention ( invention 11), since a foam can be given a softness | flexibility and elasticity by mix | blending the said substance with a matrix resin, when filling a foam into a desalination chamber and / or a concentration chamber, The foam is appropriately deformed along the shape of the chamber in the desalting chamber and / or the concentration chamber, whereby a short circuit of the water to be treated can be prevented and high-purity treated water can be obtained. In addition, since the ion exchanger and the ion exchange membrane can be more closely attached, the movement of ions can be promoted.

In the said invention ( invention 1-11), it is preferable that the pore total area of the cross section of the said water flow direction of the said foam is larger than the total pore area of the cross section of the direction orthogonal to the said water flow direction ( invention 12). ).

According to the said invention ( invention 12), while ensuring the fine pore total area of a water flow direction cross section, while being able to suppress a raise of water flow differential pressure, it is orthogonal to the water flow direction which is an ion movement direction. By reducing the total pore area of the cross section in the direction, the total cross-sectional area of the ion exchanger serving as the ion movement path can be increased, and ion movement can be promoted.

Moreover, this invention provides the pure water manufacturing system characterized by including the electrodeionization apparatus which concerns on the said invention ( invention 1-12) ( invention 13).

  ADVANTAGE OF THE INVENTION According to this invention, the electrodeionization apparatus using the filler which has a function and intensity | strength equivalent to or higher than an ion exchange resin, and has ion conductivity can be provided.

Hereinafter, an electrodeionization apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.
1 and 2 are schematic configuration diagrams of the electrodeionization apparatus according to the present embodiment, and FIG. 3 is a schematic flowchart showing a pure water production system using the electrodeionization apparatus according to the present embodiment. .

  As shown in FIG. 1, the electrodeionization apparatus 1 according to this embodiment includes a plurality of cation exchange membranes 4 and anion exchange membranes 5 disposed between a cathode 6 and an anode 7, and the cation exchange membrane 4. A plurality of desalting chambers 2 and concentration chambers 3 formed between the anion exchange membrane 5 and the anion exchange membrane 5, respectively.

  In the electrodeionization apparatus 1 according to this embodiment, the demineralization chamber 2 and the concentration chamber 3 are filled with a foam 8 having an open cell structure that holds a fine ion exchanger. Since the foam 8 has an open cell structure, the water to be treated W1 passed through the desalting chamber 2 passes through the open cells (pores) of the foam 8, and thus the desalting chamber 2. The water differential pressure can be reduced. At that time, the ion exchanger held in the foam 8 and the water to be treated are effectively in contact with each other, so that the movement of ion components in the water to be treated is promoted, and the high-purity desorption from the desalting chamber 2 is promoted. Ionized water is obtained.

  The foam 8 may hold an ion exchange resin fine powder, may hold an ion exchange short fiber, or may hold both an ion exchange resin fine powder and an ion exchange short fiber. Also good.

  The fine ion exchanger held in the foam 8 may be only an ion exchanger having an anion exchange group (anion exchanger), or an ion exchanger having a cation exchange group (cation exchanger). Only an anion exchanger and a cation exchanger. When the ion exchanger is an anion exchanger and a cation exchanger, the anion exchanger and the cation exchanger are preferably held in the foam 8 at a volume ratio of 1: 9 to 9: 1. It is more preferable that the foam 8 is held at a ratio of 3: 7 to 7: 3.

  The average particle diameter of the ion-exchange resin fine powder is preferably 100 μm or less, particularly preferably 50 μm or less, and 90% by mass or more of the ion-exchange resin fine powder held in the foam 8 is It is preferable that the particle diameter is 200 μm or less. When the particle diameter of the ion-exchange resin fine powder is within the above range, the ion-exchange resin fine powder can be uniformly dispersed and held in the entire foam 8, and the water to be treated, the ion-exchange resin fine powder, Can be more effectively brought into contact with each other, so that higher-purity deionized water W2 can be obtained.

  Further, the average fiber length of the ion exchange short fibers is preferably 2.5 mm or less, particularly preferably 1.0 mm or less, and 90 mass of the ion exchange short fibers held in the foam 8. % Or more of the fiber length is preferably 5.0 mm or less. When the fiber length of the ion-exchange short fiber is within the above range, the ion-exchange short fiber can be uniformly dispersed and held in the entire foam 8, and the treated water and the ion-exchange short fiber are more effective. Therefore, higher-purity deionized water W2 can be obtained.

  The open cell ratio of the foam 8 is preferably 30% or more, and particularly preferably 50% or more. Thereby, while being able to reduce the water flow differential pressure of the desalting chamber 2, since the foam 8 has a softness | flexibility, the foam 8 is easily filled into the desalination chamber 2 and the concentration chamber 3. be able to.

  Moreover, it is preferable that the average bubble diameter of the bubble of the foam 8 is 1-1000 micrometers, and it is especially preferable that it is 10-500 micrometers. If the average bubble diameter is less than 1 μm, the water flow differential pressure becomes too high, which may be unrealistic. If it exceeds 1000 μm, the contact between the water to be treated and the ion exchanger becomes insufficient, There is a risk that high-purity treated water cannot be obtained. Further, the expansion ratio of the foam 8 is preferably 5 to 50 times.

  As the matrix resin constituting the foam 8, a synthetic resin generally used for the production of the foam may be used. Examples of such synthetic resins include polystyrene (including impact resistance), AS resin, ABS resin, polyethylene (including modification), polypropylene, poly-1,2-butadiene, polyvinyl chloride, insolubilized polyvinyl alcohol, Thermoplastic resin such as polyamide; Thermosetting resin such as polyurethane, phenol resin, urea resin, epoxy resin, acrylic resin, silicone, pyranyl resin, polyisocyanurate, polyimide; Cellulosic resin such as acetylcellulose, viscose; ethylene An olefin copolymer such as a propylene copolymer, an ethylene-butene copolymer, an ethylene-vinyl acetate copolymer, a mixture of two or more of these olefin copolymers, an olefin copolymer and an atactic structure, Isotactic structure or gindiota Mixtures of polypropylene with tic structure including but not limited to.

  In addition, as a matrix resin which comprises the foam 8, you may use the copolymer (monomer) which has ion exchange groups, such as a sulfonic acid group or a carboxyl group, and ethylene. By using these materials, an ion exchange group can be introduced into the molecular chain of the matrix resin constituting the foam 8.

  Examples of the monomer (monomer) having a sulfonic acid group include vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and 3-allyloxy-2-hydroxypropane sulfonic acid. However, it is not limited to these. Examples of the monomer (monomer) having a carboxyl group include, but are not limited to, acrylic acid, maleic acid, itaconic acid, methacrylic acid and the like.

  The foam 8 further contains 5 to 50% by mass of at least one of acrylate resin, acrylate rubber, natural rubber, butyl rubber, polyisoprene, polychloroprene, styrene-butadiene rubber, and nitrile rubber. Also good. By containing these substances, the foam can be made flexible and elastic. Therefore, when the foam 8 is filled in the desalting chamber 2 and / or the concentration chamber 3, the foam 8 is desalted. The chamber 2 and / or the concentrating chamber 3 is appropriately deformed along the chamber shape, thereby preventing a short circuit of the water to be treated W1 and obtaining high-purity deionized water W2. In addition, the ion exchanger and the ion exchange membrane (cation exchange membrane 4, anion exchange membrane 5) can be more closely attached, and the movement of ions can be promoted.

  In order to produce the foam 8, first, ion exchange resin fine powder and / or ion exchange short fibers (anion exchange short fibers and cation exchange short fibers) obtained by crushing an anion exchange resin and a cation exchange resin with a ball mill or the like. Fiber) is added to the matrix resin constituting the foam 8.

  The addition amount of ion-exchange resin fine powder and / or ion-exchange short fibers to the matrix resin constituting the foam 8 is preferably 20 to 80% by mass, particularly 50 to 80% by mass, based on the matrix resin. Is preferred.

  Next, an extruder containing a matrix resin to which ion-exchange resin fine powder and / or ion-exchange short fibers are added, a foaming agent, and additives such as an anti-shrinkage agent, an antioxidant, and an antistatic agent as necessary And melt mixed under pressure.

  Examples of the blowing agent include lower aliphatic hydrocarbons such as propane, butane, isobutane and pentane; 1,1,1,3,3-pentafluoropropane, 1,1-dichloro-1-fluoroethane, 1-chloro Use a fluorocarbon foaming agent such as -1,1-difluoroethane, 2-chloro-1,1,1,2-tetrafluoroethane, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane, etc. Can do. These foaming agents may be used alone or in combination of two or more. When two or more kinds are mixed and used, their mixing ratio may be set as appropriate.

  The compounding quantity of a foaming agent should just be 3-50 mass% with respect to the matrix resin which comprises the foam 8, and it is preferable that it is 5-20 mass%. If the blending amount of the foaming agent is less than 3% by mass with respect to the matrix resin constituting the foam 8, the foaming ratio of the foam 8 may be reduced, and if it exceeds 50% by mass, There is a risk of bubbles breaking.

  The extruder is not particularly limited as long as it is generally used for extrusion foaming. For example, a single-screw extruder, a twin-screw extruder, and a plurality of extruders are connected in series. And a tandem type extruder.

  By extruding the mixture thus obtained with an extruder, a foam having a closed cell structure can be formed, and further, the foam having the closed cell structure can be compressed by being sandwiched between flat plates or the like. By applying a mechanical external force to the foam having the closed cell structure such as compression through a biaxial roll, the closed cells of the foam can be broken. Thereby, the foam 8 having an open cell structure in which a fine ion exchanger is held can be obtained.

When the foam 8 thus obtained is filled in the demineralization chamber 2 and the concentration chamber 3 of the electrodeionization device 1, the cation exchange membrane 4 and the anion of the electrodeionization device 1 are obtained. It is preferable that a plurality of concavo-convex portions are formed on the contact surface that contacts each of the exchange membranes 5. Thereby, the surface area of the said contact surface can be enlarged, the ion exchange group density in a contact surface can be made high-density, the cation component and anion component in to-be-processed water, and the inside of the electrodeionization apparatus 1 Migration of acid (H ⁺ ) and alkali (OH ⁻ ) generated by water dissociation can be promoted.

  Furthermore, it is preferable that a fine ion exchanger is fixed to the contact surface. Thereby, the ion exchange group density on the contact surface can be further increased.

  The foam 8 filled in the desalting chamber 2 and the concentration chamber 3 has a total pore area in the cross section in the water passage direction of the foam 8 that is larger than a total pore area in the cross section in the direction perpendicular to the water flow direction. Larger is preferred. As a result, by ensuring the total pore area of the cross section in the water passage direction, it is possible to suppress an increase in the water flow differential pressure and to reduce the total pore area in the cross section in the direction orthogonal to the water passage direction that is the ion movement direction By reducing the area, it is possible to increase the total cross-sectional area of the ion exchanger serving as the ion movement path, and promote the movement of ions.

  Since the foam 8 obtained in this way has an appropriate flexibility, when filling the desalting chamber 2 and the concentrating chamber 3 of the electrodeionization apparatus 1, the foam 8 is contained in the desalting chamber 2 and the concentrating chamber 3. It is easy to fill closely, and the production efficiency of the electrodeionization apparatus 1 can be improved.

  In the electrodeionization apparatus 1 having such a configuration, when the water to be treated W1 is supplied to the demineralization chamber 2, the cations in the water to be treated W1 permeate the cation exchange membrane 4 and the concentration chamber 3 on the anode side. The anion passes through the anion exchange membrane 5 and moves to the concentration chamber 3 on the cathode side.

  At this time, since the desalting chamber 2 is filled with the foam 8 holding the ion exchanger, the water to be treated W1 supplied to the desalting chamber 2 passes through the pores of the foam 8. In effective contact with the ion exchanger. Thereby, while the movement of the ion component in the to-be-processed water W1 is accelerated | stimulated, the water flow differential pressure | voltage of the desalination chamber 2 reduces. Moreover, when the ion exchanger is fixed to the contact surface of the foam 8 that contacts the cation exchange membrane 4 and the anion exchange membrane 5 in the desalting chamber 2, and the ion exchange group density is high. Further, the movement of cations toward the cation exchange membrane 4 is further promoted, and the movement of anions toward the anion exchange membrane 5 is further promoted. Thereby, deionized water W2 of higher purity can be obtained.

  A part of the deionized water W2 thus obtained can be introduced into the concentration chamber 3, and the circulating water in the concentration chamber 3 is diluted with the deionized water W2 to reduce the calcium concentration. Then, the concentrated water W3 is discharged.

The electrodeionization apparatus 1 having the above configuration can be applied to the pure water production system 10 shown in FIG.
As shown in FIG. 4, the pure water production system 10 includes an activated carbon device 11 to which treated water W1 serving as city water is supplied, a reverse osmosis membrane (RO membrane) device 12 that processes permeated water of the activated carbon device 11, In this embodiment, the deaeration membrane 13 for treating the RO treated water that has passed through the RO membrane device 12 and the deaerated water obtained by the deaeration membrane 13 are treated in the demineralization chamber 2 to produce deionized water W2. The electrodeionization apparatus 1 which concerns is provided.

  In such a pure water production system 10, city water (treated water W1) is supplied to the activated carbon device 11 to adsorb and remove fine particles and the treated water of the activated carbon device 11 is supplied to the RO membrane device 12 to be treated. Remove calcium, silica, etc. contained in water. And after supplying the RO treatment water processed with the RO membrane apparatus 12 to the deaeration membrane 13 and removing the carbonate ion etc. which are contained in the RO treatment water as carbon dioxide, the obtained deaeration water is electrodeionized. It supplies to the desalination chamber 2 of the apparatus 1.

  In the electrodeionization apparatus 1, the degassed water supplied to the desalting chamber 2 passes through the pores of the foam 8 filled in the desalting chamber 2 and is taken out from the outlet of the desalting chamber 2. At this time, the anion component in the deaerated water supplied to the desalting chamber 2 permeates the anion exchange membrane 4 and moves from the desalting chamber 2 to the concentration chamber 3 on the cathode side, and the cation component passes through the cation exchange membrane 5. It passes through and moves from the desalting chamber 2 to the concentration chamber 3 on the anode side. Thereby, the deionized water W2 from which the ionic component has been removed is supplied from the outlet of the desalting chamber 2 to the subsystem or the like.

  According to the electrodeionization apparatus 1 which concerns on this embodiment demonstrated above, the demineralization chamber 2 is filled with the foam 8, and the demineralization chamber is because the said foam 8 has an open-cell structure. The treated water W <b> 1 supplied to 2 passes through the pores of the foam 8, and the water flow differential pressure in the desalting chamber 2 is reduced as compared to the case where the ion-exchange resin is filled in the desalting chamber 2. can do. Further, since the ion exchanger held in the foam 8 is fine, the ion exchange group density in the desalting chamber 2 can be increased, and the water to be treated W1 in the desalting chamber 2 can be increased. Can be prevented, and high-purity deionized water W2 can be obtained. In addition, since the foam 8 has moderate flexibility, it can be easily filled into the demineralization chamber 2 and the concentration chamber 3, and the production efficiency of the electrodeionization apparatus 1 can be improved.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  In the above embodiment, the foam 8 is filled in the demineralization chamber 2 and the concentration chamber 3 of the electrodeionization apparatus 1, but only one of the demineralization chamber 2 and the concentration chamber 3 is filled with the foam 8. The foam 8 may be filled in at least the desalting chamber 2. For example, when the desalination chamber 2 is filled with the foam 8, the concentration chamber 3 may be filled with an ion exchanger such as a granular (bead-shaped) anion exchange resin and / or a cation exchange resin.

  In the above embodiment, the foam 8 holds the anion exchange resin and the cation exchange resin, but only one of the anion exchange resin and the cation exchange resin may be held by the foam 8.

  Furthermore, in the said embodiment, when manufacturing the foam 8, an ion exchanger (ion exchange resin fine powder and / or ion-exchange short fiber) is added to the matrix resin which comprises the foam 8, and a foaming agent etc. However, the present invention is not limited to this, and an ion exchanger may be added to the foaming agent and melt-mixed with a matrix resin or the like constituting the foam.

  Furthermore, in the said embodiment, as shown in FIG. 4 and FIG. 5, the electrodeionization apparatus 1 is the structure which made the water flow direction to the concentration chamber 3 the same direction as the water flow direction of the to-be-processed water W1. The pure water production system 10 may have a configuration in which the recovery RO 12A is provided in the two-stage RO 12 as shown in FIG.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
In the following Examples and Comparative Examples, an electrodeionization apparatus (manufactured by Kurita Kogyo Co., Ltd., product name: Critenon SH type, amount of treated water: 420 L / hr) was used as a test apparatus.

Moreover, the following water quality | types which processed the city water with the activated carbon apparatus and the reverse osmosis membrane apparatus (Nitto Denko Co., Ltd. product name: ES-20) were prepared as to-be-processed water for a test.
<Water quality of treated water>
Electrical conductivity: 9μS / cm
CO ₂ concentration: 3.8 ppm
SiO ₂ concentration: 0.8 ppm
Water temperature: 15 ° C

[Example 1]
The following are used as the ion exchange membrane of the electrodeionization apparatus, the ion exchanger A filled in the demineralization chamber and the ion exchanger B filled in the concentration chamber, and the configuration shown in FIGS. 3 is used to conduct the water to be treated in the pure water production system configured as shown in FIG. 3, and the time-dependent changes in the inlet conductivity of the electrodeionization apparatus, the specific resistance value of the treated water, and the applied voltage are examined. It was. The results are shown in Table 1.
Anion exchange membrane: "Aciplex A501SB" manufactured by Asahi Kasei Kogyo Co., Ltd.
Cation exchange membrane: "Aciplex K501SB" manufactured by Asahi Kasei Corporation
Ion exchanger A: Foam produced as follows Anion exchange resin (Mitsubishi Chemical Co., product name: SA10A) and cation exchange resin (Mitsubishi Chemical Co., product name: SK1B) volume mixing ratio 6: The mixture mixed in 4 was crushed with a ball mill to obtain ion-exchange resin fine powder (average particle size: 7 μm). The obtained ion-exchange resin fine powder was applied to a matrix resin (ethylene-propylene-vinyl vinyl sulfonate copolymer) and a foaming agent (a mixture of butane and 1,1,1,3,3-pentafluoropropane). Added to each of the above. A matrix resin (85% by mass), a foaming agent (14% by mass) and an anti-shrinkage agent (stearic monoglyceride, 1% by mass) obtained in this manner were added to an extruder (manufactured by Moriyama Co., Ltd., twin-screw single-screw extruder). ) And melt-mixing under pressure to form a foam having a closed cell structure, and then compressing the foam having a closed cell structure to apply a mechanical external force to break the cell wall and continuously A foam having a cell structure was obtained.
The ion-exchange resin fine powder was mixed with 75% by mass with respect to the matrix resin and 35% by mass with respect to the foaming agent. In the obtained foam, the contact surfaces that come into contact with the cation exchange membrane and the anion exchange membrane are subjected to embossing, the ion exchange resin fine powder is applied to the contact surface, and the ion exchange resin fine powder is heated and pressed. Fused.
Ion exchanger B: Anion exchange resin (Mitsubishi Chemical Corporation, product name: SA10A) and cation exchange resin (Mitsubishi Chemical Corporation, product name: SK1B) mixed at a volume mixing ratio of 6.4.

[Comparative Example 1]
The water to be treated was passed in the same manner as in Example 1 except that the desalting chamber was filled with the following ion exchanger C. The results are shown in Table 1.
Ion exchanger C: anion exchange fiber (Nichibi, product name: IEF-SC, fiber length: 2.0 mm) and cation exchange fiber (Nichibi, product name: IEF-SA, fiber length: 2.0 mm) After the cut yarn is mixed at a volume mixing ratio of 6: 4, it is made into a nonwoven fabric.

[Comparative Example 2]
The treated water was passed in the same manner as in Example 1 except that the desalting chamber was filled with the ion exchanger B. The results are shown in Table 1.

  As shown in Table 1, in Comparative Example 1, the specific resistance value of the treated water reached only 14 MΩ · cm. In Comparative Example 2, the specific resistance value of the treated water reached 18 MΩ · cm and sufficient treated water quality was obtained, but the water flow differential pressure in the desalting chamber was the highest at 88 kPa. On the other hand, in Example 1, the specific resistance value of the treated water reached 18 MΩ · cm, and the water flow differential pressure in the desalting chamber was about half that of Comparative Example 2 filled with the ion exchange resin. In addition, it was confirmed that the electrodeionization apparatus according to Example 1 can significantly reduce the assembly time of the apparatus as compared with the electrodeionization apparatuses according to Comparative Examples 1 and 2.

It is an enlarged view which shows the demineralization chamber and the concentration chamber of the electrodeionization apparatus which concerns on one Embodiment of this invention. It is the schematic which shows the flow of the water to the demineralization chamber and concentration chamber of the electrodeionization apparatus which concerns on one Embodiment of this invention. It is the schematic which shows the pure water manufacturing system using the electrodeionization apparatus which concerns on one Embodiment of this invention. It is an enlarged view which shows the demineralization chamber and the concentration chamber of the electrodeionization apparatus which concerns on other embodiment of this invention. It is the schematic which shows the flow of the water to the demineralization chamber and the concentration chamber of the electrodeionization apparatus which concerns on other embodiment of this invention. It is the schematic which shows the pure water manufacturing system using the electrodeionization apparatus which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electrodeionization apparatus 2 ... Desalination chamber 3 ... Concentration chamber 4 ... Cation exchange membrane 5 ... Anion exchange membrane 6 ... Cathode 7 ... Anode 8 ... Foam 10 ... Pure water manufacturing system

Claims (12)

An electrodeionization apparatus in which a plurality of anion exchange membranes and cation exchange membranes are arranged between a cathode and an anode to form a demineralization chamber and a concentration chamber,
The desalting chamber and / or the concentration chamber is filled with a foam having an open-cell structure that holds a fine ion exchanger ,
The electrodeionization apparatus according to claim 1, wherein the foam is formed by adding 20 to 80% by mass of the ion exchanger to the foaming agent .   The electrodeionization apparatus according to claim 1, wherein the ion exchanger is an anion exchanger or a cation exchanger.   The electrodeionization apparatus according to claim 2, wherein a volume ratio of the anion exchanger and the cation exchanger held in the foam is 1: 9 to 9: 1.   The ion exchange group density in the contact surface of the foam in contact with the anion exchange membrane or the cation exchange membrane is higher than the ion exchange group density in other parts of the foam. The electrodeionization apparatus according to any one of the above. A plurality of irregularities are formed on the contact surface of the foam,
The electrodeionization apparatus according to claim 4, wherein the foam is formed by further fixing the ion exchanger to the contact surface. The ion exchanger includes at least an ion exchange resin;
6. The electrodeionization apparatus according to claim 1, wherein the ion-exchange resin has an average particle size of 100 μm or less and 90% by mass or more of an ion-exchange resin having a particle size of 200 μm or less. . The ion exchanger includes at least ion exchange fibers,
The average fiber length of the ion-exchange fiber is 2.5 mm or less, and 90% by mass or more of ion-exchange fibers having a fiber length of 5.0 mm or less are included. Electrodeionizer. The foam, the said ion exchanger from 20 to 80 wt% with respect to the matrix resin constituting the foam of claim 1 to 7, characterized in that formed by formed by adding to said matrix resin The electrodeionization apparatus in any one. The electrodeionization apparatus according to claim 8 , wherein an ion exchange group is introduced into a molecular chain of the matrix resin. The matrix resin contains 5 to 50% by mass of at least one of acrylate resin, acrylate rubber, natural rubber, butyl rubber, polyisoprene, polychloroprene, styrene-butadiene rubber, and nitrile rubber. The electrodeionization apparatus according to claim 8 or 9 . The electricity according to any one of claims 1 to 10 , wherein a total pore area of a cross section in the water flow direction of the foam is larger than a total pore area of a cross section in a direction orthogonal to the water flow direction. Deionizer. Water purification system characterized in that it comprises an electrodeionization apparatus according to any one of claims 1 to 11.

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