JPWO2018117035A1 - Deionized water production system, electric deionized water production apparatus, and deionized water production method - Google Patents

Abstract

A deionized water production system for producing deionized water by being supplied with raw water is divided by a reverse osmosis membrane device (RO device) to which raw water is supplied and an ion exchange membrane, and is supplied with permeated water of the reverse osmosis membrane device. An electric deionized water production apparatus (EDI apparatus) having a demineralization chamber. In an EDI apparatus, the inside of a desalting chamber is filled with an ion exchanger, and particles containing a polyvalent metal are adsorbed on at least one surface of at least a part of the ion exchange membrane and at least a part of the ion exchanger. Has been.

Description

  The present invention relates to the production of deionized water, and more particularly to a deionized water production system, an electric deionized water production apparatus, and a deionized water production method.

2. Description of the Related Art A deionized water production system is known in which water to be treated is passed through an ion exchanger such as an ion exchange resin and deionized by an ion exchange reaction. Such a system generally includes an apparatus having an ion exchanger and generates deionized water using an ion exchange reaction by the ion exchanger. However, in an apparatus having an ion exchanger, when the ion exchange group of the ion exchanger is saturated and the desalting performance is reduced, it is necessary to regenerate the ion exchanger with a chemical such as acid or alkali, that is, to perform a regeneration process. There is. In the regeneration treatment, cations (cations) and anions (anions) adsorbed on the ion exchanger are replaced with hydrogen ions (H ⁺ ) and hydroxide ions (OH ⁻ ) derived from acids or alkalis. This process restores the desalination performance of the exchanger. Therefore, a deionized water production apparatus using an ion exchanger has a problem that continuous operation cannot be performed and it takes time to replenish a drug for regeneration treatment. In order to solve this problem, in recent years, an electric deionized water production apparatus (also referred to as an EDI (ElectroDeIonization) apparatus) that does not require regeneration by a drug has been developed and put into practical use.

  The EDI device is a combination of electrophoresis and electrodialysis. A desalination chamber is formed by filling an ion exchanger between an anion exchange membrane that allows only anions to pass through and a cation exchange membrane that allows only cations to pass through. The concentration chamber is disposed outside the anion exchange membrane and the cation exchange membrane as viewed from the desalting chamber, and further, the anode chamber including the anode and the cathode chamber including the cathode are disposed outside them. . The ion exchanger filled in the desalting chamber is at least one of an anion exchanger and a cation exchanger. In the desalting chamber, an anion exchange membrane is disposed on the side facing the anode, and a cation exchange membrane is disposed on the side facing the cathode. The concentration chamber may be filled with an ion exchanger, the anode chamber may be filled with a cation exchanger, and the cathode chamber may be filled with an anion exchanger.

  In order to produce deionized water from the water to be treated by the EDI apparatus, the water to be treated is passed through the desalting chamber with a DC voltage applied between the anode and the cathode. Then, the ion component in to-be-processed water will be adsorb | sucked by the ion exchanger in a desalination chamber, and a deionization process, ie, a desalination process, will be performed. As a result, deionized water flows out of the desalting chamber. At this time, in the desalting chamber, an interface between different types of ion exchange materials, that is, an interface between an anion exchanger and a cation exchanger, an interface between an anion exchanger and a cation exchange membrane, an anion exchange membrane and a cation exchanger, At the interface and at the interface between the anion exchange membrane and the cation exchange membrane, a dissociation reaction of water occurs as shown in the following formula by the applied voltage, and hydrogen ions and hydroxide ions are generated.

H ₂ O → H ⁺ + OH ⁻
By the hydrogen ions and hydroxide ions generated by this dissociation reaction, the ion component previously adsorbed on the ion exchanger in the desalting chamber is ion-exchanged and released from the ion exchanger. Of the released ionic components, the anion is electrophoresed to the anion exchange membrane, electrodialyzed on the anion exchange membrane, and discharged to the concentrated water flowing through the concentration chamber closer to the anode as viewed from the desalting chamber. Similarly, cations out of the released ionic components are electrophoresed to the cation exchange membrane, electrodialyzed by the cation exchange membrane, and discharged to the concentrated water flowing through the concentration chamber closer to the cathode as viewed from the desalting chamber. Eventually, the ion component in the for-treatment water supplied to the desalting chamber is transferred to the concentration chamber and discharged, and at the same time, the ion exchanger in the desalting chamber is also regenerated.

  In this way, in the EDI apparatus, hydrogen ions and hydroxide ions generated by applying a DC voltage continuously act as acid and alkali regenerants for regenerating the ion exchanger. For this reason, in the EDI apparatus, it is basically unnecessary to perform the regeneration process with the medicine supplied from the outside, and the continuous operation can be performed without regenerating the ion exchanger with the medicine.

  In the above, the basic configuration of [concentration chamber (C) | anion exchange membrane (AEM) | desalting chamber (D) | cation exchange membrane (CEM) | concentration chamber (C)] is arranged between the anode and the cathode. It was supposed to be. This basic configuration is called a cell set. Actually, a plurality of such cell sets are juxtaposed between the electrodes, and the plurality of cell sets are electrically connected in series with one end serving as an anode and the other end serving as a cathode, thereby increasing the processing capability. It is common. In this case, since adjacent concentrating chambers can be shared between adjacent cell sets, the configuration of the EDI apparatus is [anode chamber | C | AEM | D | CEM | C | AEM | D | CEM | C | AEM | D | CEM | ... | C | cathode chamber]. In many cases, a cation exchange membrane is provided between the anode chamber and the concentrating chamber adjacent thereto, and an anion exchange membrane is provided between the cathode chamber and the concentrating chamber adjacent thereto. Further, in such a series structure, the desalination chamber closest to the anode chamber can function as the concentration chamber without interposing an independent concentration chamber between the anode chamber and the anode chamber. Similarly, for the desalting chamber closest to the cathode chamber, the cathode chamber itself can function as a concentration chamber without interposing a concentration chamber between the cathode chamber and the cathode chamber. In order to suppress the power consumed by the application of the DC voltage, it is preferable to fill each of the concentration chamber, the anode chamber, and the cathode chamber with an ion exchanger to lower the electric resistance.

  In order to obtain deionized water having a remarkably low impurity concentration in a deionized water production system equipped with an EDI device, it is preferable to use water in which impurities have been reduced to some extent as the water to be treated supplied to the EDI device. For this reason, for example, a reverse osmosis (RO) membrane device is provided upstream of the EDI device to constitute a deionized water production system, and water that has passed through the reverse osmosis membrane device is supplied as treated water to the EDI device. ing. However, when the conductivity of the water to be treated is reduced, for example, 5 μS / cm or less, the voltage that must be applied to the EDI apparatus to cause the water dissociation reaction is increased. If treated water with lower conductivity is used in order to obtain deionized water having a lower impurity concentration, if the current flowing between the anode and the cathode is constant, the voltage that must be applied to the EDI device, that is, The operating voltage is higher. As the operating voltage increases, the power consumption increases accordingly.

  As described above, it is the water dissociation reaction in the demineralization chamber that plays an important role in the continuous production of deionized water by the EDI apparatus. If the water dissociation reaction is carried out efficiently, the applied voltage to the EDI apparatus can be kept low even when the conductivity of the water to be treated is small, so that high purity deionized water can be consumed with low power consumption. It becomes possible to manufacture.

  Several techniques have been proposed to facilitate the water dissociation reaction in the desalination chamber of EDI devices. Patent Document 1 discloses that, in an EDI apparatus, a metal hydroxide such as magnesium hydroxide is supported on a membrane surface on the desalting chamber side of a cation exchange membrane or an ion exchange resin filled in the desalting chamber. Yes. Patent Document 2 discloses that in an EDI apparatus, a metal oxide or metal hydroxide acting as an amphoteric ion exchanger is mixed in an ion exchanger in a desalting chamber at a volume ratio of 1 to 50%. ing.

JP 2000-350991 A JP 2001-340865 A

  However, in the apparatus described in Patent Document 1, since the metal hydroxide supported in the desalting chamber is dissolved by hydrogen ions generated by the dissociation of water, the performance can be stably maintained over a long period of time. difficult. In the apparatus described in Patent Document 2, since the metal oxide or metal hydroxide mixed in the ion exchanger does not surely exist at the interface of different types of ion exchangers, the effect of promoting water dissociation is maximized. It cannot be demonstrated to the limit.

  In view of the problems of the conventional deionized water production system as described above, the object of the present invention is more stable and even when treated water having a low electrical conductivity is supplied to an electric deionized water production apparatus. Suitable for deionized water production system, deionized water production method, and deionized water production system capable of efficiently promoting dissociation of water and producing high purity deionized water with low power consumption An object of the present invention is to provide an electric deionized water production apparatus to be used.

  Another object of the present invention is to provide at least one of an ion exchange membrane and an ion exchanger used in an electric deionized water production apparatus.

  According to one aspect of the present invention, a deionized water production system for producing deionized water by supplying raw water includes a reverse osmosis membrane device to which raw water is supplied, and a permeation of the reverse osmosis membrane device partitioned by an ion exchange membrane. An electric deionized water production apparatus having a demineralization chamber to which water is supplied, and the inside of the demineralization chamber is filled with an ion exchanger, at least a part of the ion exchange membrane, and at least the ion exchanger Part of at least one surface is adsorbed with particles containing a polyvalent metal.

  According to another aspect of the present invention, an electrical deionized water production apparatus (EDI apparatus) includes at least one demineralization chamber between an anode chamber having an anode and a cathode chamber having a cathode. The salt chamber is partitioned by an anion exchange membrane located on the side facing the anode and a cation exchange membrane located on the side facing the cathode, and at least one of the anion exchanger and the cation exchanger is filled in the desalting chamber. In the EDI apparatus, particles containing a polyvalent metal are adsorbed on at least one surface of an anion exchange membrane, a cation exchange membrane, an anion exchanger, and a cation exchanger.

  A polyvalent metal, that is, a metal element having an ionic value of 2 or more when it becomes a cation acts as a catalyst for water dissociation reaction. In the present invention, particles containing a polyvalent metal are adsorbed on at least one surface of an anion exchanger, a cation exchanger, an anion exchange membrane, and a cation exchange membrane in the desalting chamber, so A polyvalent metal acting as a catalyst for the water dissociation reaction can surely be present at the interface between the ion exchange materials. For this reason, in this invention, the promotion effect of the water dissociation reaction by a polyvalent metal can be acquired to the maximum. In addition, since the particles containing polyvalent metal have the shape of particles, there is no possibility of covering their surfaces when adsorbed to the ion exchanger or ion exchange membrane in the demineralization chamber. The loss of ion exchange reactivity and ion permeability associated with the can be minimized.

According to still another aspect of the present invention, the method for producing deionized water is the method for producing deionized water using the EDI apparatus of the present invention described above, wherein the current density in the demineralization chamber is 0.3 A / dm ² or more. Deionized water is obtained by flowing water to be treated into the desalting chamber while applying a DC voltage between the anode and the cathode so that the current is 10 A / dm ² or less.

  According to still another aspect of the present invention, a method for producing deionized water includes at least one demineralization chamber between an anode chamber having an anode and a cathode chamber having a cathode, the demineralization chamber serving as an anode. An EDI apparatus was used which was partitioned by an anion exchange membrane located on the facing side and a cation exchange membrane located on the side facing the cathode, and in which at least one of an anion exchanger and a cation exchanger was filled in the desalting chamber. In the method for producing deionized water, an anion exchange membrane, a cation exchange membrane, an anion exchanger, a step of adsorbing particles containing a polyvalent metal on at least one surface of the cation exchanger, And a step of flowing treated water into the desalting chamber while applying a DC voltage between the cathode and the cathode to obtain deionized water.

  According to still another aspect of the present invention, an ion exchange membrane for an EDI apparatus comprises an anode chamber having an anode and a cathode having at least one desalting chamber filled with at least one of an anion exchanger and a cation exchanger. An anion exchange membrane which is used in an EDI apparatus provided between the cathode chamber and is provided on the side facing the anode in the desalting chamber, and is located on the side facing the cathode in the desalting chamber. In an ion exchange membrane that is at least one of a cation exchange membrane that partitions the desalting chamber and an intermediate ion exchange membrane that further partitions the desalting chamber into smaller desalting chambers, a polyvalent metal is formed on the surface of the ion exchange membrane. It is characterized by adsorbing contained particles.

  According to still another aspect of the present invention, an ion exchanger for an EDI apparatus includes at least one desalting chamber between an anode chamber having an anode and a cathode chamber having a cathode, and the desalting chamber is an anode. Used in an EDI apparatus partitioned by an anion exchange membrane located on the side facing the cathode and a cation exchange membrane located on the side facing the cathode, and includes at least one of the anion exchanger and the cation exchanger. The ion exchanger to be filled is characterized in that particles containing a polyvalent metal are adsorbed on the surface of the ion exchanger.

  According to the present invention, the particles containing the polyvalent metal are adsorbed on the ion exchanger or ion exchange membrane in the demineralization chamber of the EDI apparatus, so that the polyvalent metal is Compared to an EDI apparatus that does not use the particles that contain it, the dissociation reaction of water can be more stably and efficiently promoted, whereby high-purity deionized water can be produced with low power.

It is a figure which shows the structure of the deionized water manufacturing system based on this invention. It is a figure which shows another example of a structure of a deionized water manufacturing system. It is a figure which shows another example of a structure of a deionized water manufacturing system. It is a schematic cross section which shows the basic form of an electrical deionized water manufacturing apparatus (EDI apparatus). It is a figure explaining promotion of water dissociation by the particle containing a polyvalent metal. It is a figure explaining promotion of water dissociation by the particle containing a polyvalent metal. It is a schematic cross section which shows another form of the EDI apparatus based on this invention. It is a schematic cross section which shows another form of the EDI apparatus based on this invention. It is a schematic cross section which shows another form of the EDI apparatus based on this invention. It is a schematic cross section which shows another form of the EDI apparatus based on this invention. It is a schematic cross section which shows another form of the EDI apparatus based on this invention. It is a figure explaining promotion of water dissociation by the particle containing a polyvalent metal. It is a schematic cross section which shows another form of the EDI apparatus based on this invention. It is a schematic cross section which shows another form of the EDI apparatus based on this invention.

  Next, a preferred embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows the configuration of a deionized water production system according to the present invention. This deionized water production system is provided with the EDI device 10, but in order to obtain deionized water with a sufficiently reduced impurity concentration, reverse osmosis (two-stage reverse osmosis) provided in front of the EDI device 10 ( RO) membrane devices 51 and 52 are provided. The reverse osmosis membrane devices 51 and 52 are provided with reverse osmosis membranes 53 and 54, respectively. The raw water is supplied to the first-stage reverse osmosis membrane device 51 via the pump 55, and the water that has passed through the reverse osmosis membrane 53 in the reverse osmosis membrane device 51, that is, the permeated water, is the second-stage reverse osmosis membrane device. 52. The permeated water of the second-stage reverse osmosis membrane device 52 is supplied to the EDI device 10 as treated water. The configuration in which the two reverse osmosis membrane devices 51 and 52 are connected in series is a configuration in which devices each including the reverse osmosis membranes 53 and 54 are connected in series in two stages. The reverse osmosis membrane devices 51 and 52 used in the deionized water production system of the present embodiment are general ones used for pure water production and the like. In addition, between the illustrated pump 55, reverse osmosis membrane devices 51 and 52, and EDI device 10, tanks and pumps, ion exchange resin devices for softening and desalting purposes, and decarboxylation purposes are used as necessary. A decarboxylation tower, a membrane degassing device, and a chemical injection facility may be added as appropriate.

  As raw water, tap water, well water, river water, industrial water, etc. are used. In addition to the water to be treated, supply water is supplied to the EDI apparatus 10 as will be described later. The feed water may be, for example, permeate obtained from a reverse osmosis membrane device, or water treated with an EDI device, that is, deionized water. Although the two-stage reverse osmosis membrane devices 51 and 52 are provided here, only the first-stage reverse osmosis membrane device 52 may be provided in the front stage of the EDI device 10 as shown in FIG.

  In order to obtain deionized water with a further reduced impurity concentration than the system shown in FIG. 1, two stages of EDI devices may be connected in series. FIG. 3 shows an additional EDI device 15 arranged between the reverse osmosis membrane device 52 and the EDI device 10 in the deionized water production system shown in FIG. As the EDI device 15, one having the same configuration as the EDI device 10 can be used, or one having a different configuration can be used. The permeated water of the reverse osmosis membrane device 52 is supplied to the desalting chamber 23 of the EDI device 15, and the water flowing from the desalting chamber 23 of the EDI device 15 is supplied to the desalting chamber of the EDI device 10 as treated water. In addition, between the illustrated pump 55, reverse osmosis membrane devices 51 and 52, and EDI devices 10 and 15, tanks and pumps, ion exchange resin devices for softening and desalting purposes, and decarboxylation as necessary. A target decarboxylation tower, a membrane deaeration device, and a chemical injection facility may be appropriately added and arranged.

  In the case of the configuration shown in FIG. 3, the conductivity of the water to be treated supplied to the EDI apparatus 10 at the second stage has already been extremely small, for example, 1 μS / cm or less. When deionized water is produced using an EDI apparatus, the operating voltage of the EDI apparatus tends to be high when the conductivity of the water to be treated is small. By using this, the operating voltage of the EDI device 10 can be kept low. Since the conductivity of the water to be treated supplied to the additional EDI device 15 in the first stage is relatively large, a general EDI device can be used as the additional EDI device 15 instead of the EDI device described later. .

  In each of the deionized water production systems shown in FIGS. 1, 2 and 3, the conductivity of the water to be treated to the EDI apparatus 10 is, for example, 10 μS / cm or less, and preferably 5 μS / cm or less, It is more preferably 3 μS / cm or less, and further preferably 1 μS / cm or less.

  Next, the EDI apparatus 10 based on this invention used in the deionized water manufacturing system mentioned above is demonstrated. In the EDI apparatus 10, a concentrating chamber 22, a desalting chamber 23, and a concentrating chamber 24 are provided in this order from the anode chamber 21 side between an anode chamber 21 including the anode 11 and a cathode chamber 25 including the cathode 12. It has been. The anode chamber 21 and the concentration chamber 22 are adjacent to each other with a cation exchange membrane 31 therebetween, the concentration chamber 22 and the desalting chamber 23 are adjacent to each other with an anion exchange membrane 32 therebetween, and the desalting chamber 23 and the concentration chamber 24 are cation exchange membranes. The concentrating chamber 24 and the cathode chamber 25 are adjacent to each other with an anion exchange membrane 34 therebetween. Therefore, the desalting chamber 23 is partitioned by the anion exchange membrane 32 located on the side facing the anode 11 and the cation exchange membrane 33 located on the side facing the cathode 12. The desalting chamber 23 is filled with at least one of an anion exchanger and a cation exchanger. In the example shown here, the anion exchanger and the cation exchanger are mixed in the desalting chamber 23, that is, filled in a mixed bed configuration. Further, in the EDI apparatus 10, the cation exchanger is filled in the anode chamber 21, and the anion exchanger is filled in the concentration chambers 22 and 24 and the cathode chamber 25. Here, for example, an anion exchange resin is used as the anion exchanger, and for example, a cation exchange resin is used as the cation exchanger. The anode chamber 21, the concentration chambers 22 and 24, and the cathode chamber 25 are not necessarily filled with an anion exchanger or a cation exchanger. FIG. 4 schematically shows a cross-sectional configuration of the EDI apparatus 10 used in the deionized water production system shown in FIG. In FIG. 4, small circles drawn in the electrode chambers 21 and 25, the concentration chambers 22 and 24, and the desalting chamber 23 indicate anion exchangers and cation exchangers filled in those chambers. In FIG. 4, the anion exchanger and the anion exchange membrane have the same hatching, and the cation exchanger and the cation exchange membrane have the same hatching. The body is drawn with different hatching. The distinction between an anion exchanger and a cation exchanger by hatching, and the distinction between an anion exchange membrane and a cation exchange membrane are common in the drawings attached to this specification.

  In the following description, anion exchangers and cation exchangers are collectively referred to as ion exchangers, and anion exchange membranes and cation exchange membranes are collectively referred to as ion exchange membranes. Accordingly, the ion exchanger is at least one of an anion exchanger and a cation exchanger, and the ion exchange membrane is at least one of an anion exchange membrane and a cation exchange membrane.

  Furthermore, in this EDI apparatus 10, in the desalting chamber 23, at least a part of the ion exchanger provided in the desalting chamber 23 and at least a part of the ion exchange membranes (anion exchange membrane 32 and cation exchange membrane 33), Particles containing a polyvalent metal are adsorbed on at least one surface. The particle containing a polyvalent metal herein includes a polyvalent metal, that is, a metal element having an ionic value of 2 or more when it becomes a cation, and is an anion exchanger, a cation exchanger, an anion exchange membrane or a cation exchange membrane. It is a particle that adsorbs to and does not easily desorb mechanically after adsorption. The polyvalent metal used here is not particularly limited as long as it acts as a water dissociation catalyst, and even if it is one type of metal or a plurality of types of metals are included. Good. Examples of the metal element used as the polyvalent metal include magnesium, calcium, aluminum, chromium, manganese, iron, and nickel. As described above, the “particles containing a polyvalent metal” are considered to act as a catalyst for water dissociation. Therefore, unless otherwise specified, the “particles containing a polyvalent metal” are simply referred to as “catalyst particles”. Call.

  The catalyst particles are not particularly limited as long as they are easily adsorbed on the surface of the anion exchanger, cation exchanger, anion exchange membrane or cation exchange membrane. When the catalyst particles are an inorganic substance, the catalyst particles are preferably an inorganic ion exchange material from the viewpoint of easy adsorption. An inorganic ion exchange material is an inorganic substance having the ability to exchange ionic species by taking in ions in the electrolyte solution that is in contact with it and releasing the ions that it has instead, that is, ion exchange ability. . The catalyst particles that are inorganic ion exchange materials are easily adsorbed on the surface of an anion exchanger, cation exchanger, anion exchange membrane or cation exchange membrane. The catalyst particles are anion exchanger, cation exchanger, anion exchange membrane. Or it is estimated that it is because it adsorb | sucks through the ion exchange group which exists in these surfaces with respect to the surface of a cation exchange membrane.

As examples of catalyst particles that are inorganic ion exchange materials, silicates containing polyvalent metals can be preferably used. Examples of such silicates include aluminum silicate, magnesium silicate, calcium silicate, Examples include calcium magnesium silicate, various aluminosilicates, and various silicate minerals. One or more of these can be used alone or in combination. Among these, silicate minerals are excellent in chemical stability, and are particularly strongly adsorbed on anion exchangers and anion exchange membranes, so that more stable performance can be expected. In addition, since silicate minerals are contained in natural ores, there are many choices, which is advantageous in terms of cost. Examples of such silicate minerals include zeolite, talc, kaolinite, zeolite, and the like. Among them, sepiolite (CAS number (Chemical Abstract Service registry number): 63800-37-3, composition formula: Mg ₈ Si ₁₂ O ₃₀ (OH) ₄ (OH ₂ ) ₄ · 8H ₂ O), wollastonite (CAS number: 13983-17-0, composition formula: CaSiO ₃ ), attapulgite (CAS number: 12174-11-7, composition formula) : (Mg, Al) ₅ Si ₈ O ₂₀ · 4H ₂ O) and the like are highly suitable because of their high adsorptivity. More preferably, the catalyst particles are made of at least one of attapulgite, sepiolite, and wollastonite. Note that attapulgite, sepiolite, and wollastonite are known to be in the form of acicular particles. Silicate minerals are easily adsorbed by anion exchangers such as amino groups and quaternary ammonium groups contained in anion exchangers, for example, for hydroxy groups or oxygen atoms present on the surface of silicate minerals. It is presumed that the anion exchange groups are attracted electrostatically.

  The adsorption of the catalyst particles to the ion exchanger or the ion exchange membrane can be easily performed by, for example, immersing the ion exchanger or the ion exchange membrane in water in which the catalyst particles are dispersed. Further, by supplying water in which catalyst particles are dispersed to a desalting chamber of an existing EDI apparatus, the catalyst particles can be adsorbed to an ion exchanger or an ion exchange membrane in the desalting chamber. Therefore, it is easy to convert an existing EDI apparatus into an EDI apparatus based on the present invention, and it is also within the scope of the present invention to produce deionized water after converting an existing EDI apparatus into an EDI apparatus based on the present invention. It is included.

  The particle diameter of the catalyst particles is not particularly limited. The particle diameter of each catalyst particle can be determined by, for example, observing the catalyst particle at a magnification of about 1000 to 20000 times with a scanning electron microscope (SEM) and measuring the obtained image. When the shape of the catalyst particles is not a true sphere, the maximum diameter is the particle diameter. For example, when the catalyst particles are acicular particles, the length of the major axis is taken as the particle diameter. The range of the particle diameter of the catalyst particle is a range from the minimum value to the maximum value of the measured particle diameter by measuring the particle diameter of the catalyst particle in 10 SEM images having different observation fields of view. In the present invention, it is preferable to use catalyst particles having a particle size range of, for example, 0.01 μm or more and 100 μm or less, and more preferably 0.02 μm or more and 10 μm or less.

  If the particle size of the catalyst particles is too large, they will not be adequately adsorbed and fixed on the surface of the ion exchanger or ion exchange membrane, and the distance between the interfaces of different types of ion exchange materials will be too wide. May not be able to promote. On the other hand, if the particle size of the catalyst particles is too small, the catalyst particles cover the surface of the ion exchanger or ion exchange membrane tightly and hinder the ion exchange reaction or ion transfer in the ion exchanger or ion exchange membrane. May cause.

  Here, the ion exchanger filled in the desalting chamber 23 will be described. The type of ion exchanger that can be filled in the desalting chamber 23 is not limited to a specific one, but an ion exchange resin is preferable as exemplified above. The ion exchange resin here is a synthetic resin obtained by introducing a functional group having ion exchange ability, that is, an ion exchange group, into a polymer matrix having a three-dimensional network structure. Commonly used ion exchange resins are spherical particles having a particle size of about 0.4 to 0.8 mm. Examples of the polymer matrix of the ion exchange resin include a styrene-divinylbenzene copolymer called “styrene” and an acrylic acid-divinylbenzene copolymer called “acrylic”.

  Ion exchange resins are roughly classified into cation exchange resins whose ion exchange groups are acidic and anion exchange resins showing basicity. Furthermore, depending on the type of ion exchange groups introduced, strongly acidic cation exchange resins, weakly acidic resins are used. There are cation exchange resins, strong basic anion exchange resins, weak basic anion exchange resins and the like. Examples of strong basic anion exchange resins include those having a quaternary ammonium group as an ion exchange group, and examples of weak basic anion exchange resins include primary amines, secondary amines or tertiary amines. Some have amines as ion exchange groups. Examples of the strong acid cation exchange resin include those having a sulfonic acid group as an ion exchange group, and examples of the weak acid cation exchange resin include those having a carboxyl group as an ion exchange group. Any of these types can be used as the ion exchange resin filled in the desalting chamber, but the ion exchange resin and the catalyst particles are such that the catalyst particles are adsorbed to the ion exchange groups of the ion exchange resin. It is preferable to select a combination.

  The adsorption amount of the catalyst particles with respect to the ion exchanger in the desalting chamber 23 is 0.0001% by volume or more and less than 1% by volume in terms of a volume ratio in which the volume of the ion exchanger is 100%. Is preferable, and it is more preferable to set it as 0.0125 volume% or less. If the amount of adsorption of the catalyst particles is too large, the catalyst particles may possibly inhibit the ion exchange reaction or ion movement in the EDI apparatus 10.

  Next, the production of deionized water by the EDI apparatus 10 shown in FIG. 4 will be described.

  As in the case of the conventional EDI apparatus, desalting is performed in a state in which supply water is passed through the anode chamber 21, the concentration chambers 22 and 24, and the cathode chamber 25 and a DC voltage is applied between the anode 11 and the cathode 12. Water to be treated is passed through the chamber 23. When the water to be treated is passed through the desalting chamber 23, the ionic components in the water to be treated are adsorbed by the ion exchanger in the desalting chamber 23 and subjected to deionization treatment. As a result, deionized water flows out. At this time, in the desalting chamber 23, a dissociation reaction of water occurs at the interface between different kinds of ion-exchange materials by the applied voltage, and hydrogen ions and hydroxide ions are generated. The ion component adsorbed on the ion exchanger in the desalting chamber 23 is ion-exchanged and released from the ion exchanger. Of the released ionic components, the anion moves to the concentration chamber 22 closer to the anode through the anion exchange membrane 32 and is discharged from the concentration chamber 22 as concentrated water, and the cation passes through the cation exchange membrane 33 to the cathode. It moves to the near concentration chamber 24 and is discharged from this concentration chamber 24 as concentrated water. Eventually, ion components in the for-treatment water supplied to the desalting chamber 23 are transferred to the concentration chambers 22 and 24 and discharged, and at the same time, the ion exchanger in the desalting chamber 23 is also regenerated. Electrode water is discharged from the anode chamber 21 and the cathode chamber 25.

In the EDI apparatus 10 shown in FIG. 4, as described above, particles containing a polyvalent metal on at least one surface of the ion exchanger, the anion exchange membrane 32, and the cation exchange membrane 33 provided in the desalting chamber 23, Catalyst particles are adsorbed. The catalyst particles are present at the interface between different kinds of ion-exchange materials in the desalting chamber 23. However, since the polyvalent metal contained in the catalyst particles acts as a catalyst for promoting the water dissociation reaction, In the EDI apparatus 10, the water dissociation reaction can be performed efficiently. Therefore, the regeneration of the ion exchanger in the desalting chamber 23 can be efficiently performed, and high-purity deionized water can be produced with low power while suppressing the voltage applied to the EDI apparatus 10. . Further, since the applied voltage can be lowered, the apparatus can be operated at a high current density in the desalting chamber 23, for example, a current density of 0.3 A / dm ² or more and 10 A / dm ² or less.

  5A and 5B schematically show the dissociation reaction of water by the catalyst particles. Here, it is assumed that the catalyst particles 43 are adsorbed on the anion exchanger 42. When the cation exchanger 41 and the anion exchanger 42 constitute an interface of a different ion exchange material, as shown in FIG. 5A, dissociation of water at the interface is promoted, and the anion exchanger 42 Hydroxide ions are efficiently generated on the side and hydrogen ions are efficiently generated on the cation exchanger 41 side. Similarly, at the interface between the anion exchanger 42 and the cation exchange membrane 33, as shown in FIG. 5B, hydroxide ions are efficiently generated on the anion exchanger 42 side and hydrogen ions are efficiently generated on the cation exchange membrane 33 side. According to this EDI apparatus 10, dissociation of water at the interface between the ion exchange membrane and the ion exchanger can be promoted.

  The basic configuration of the EDI apparatus 10 according to the present invention has been described above, but the present invention can be widely applied to EDI apparatuses having various configurations. Hereinafter, a configuration example of an EDI apparatus to which the present invention can be applied will be described. In any case, particles containing polyvalent metals, that is, catalyst particles are adsorbed on at least the ion exchanger or ion exchange membrane in the desalting chamber 23. The EDI apparatus described below can be used as the EDI apparatus 10 in the deionized water production system shown in any of FIG. 1, FIG. 2, and FIG.

  FIG. 6 shows another embodiment of an EDI device according to the present invention. As described above, in the EDI apparatus, a basic configuration (that is, a cell set) consisting of [concentration chamber | anion exchange membrane (AEM) | desalination chamber | cation exchange membrane (CEM) | concentration chamber] is arranged between the anode and the cathode. A plurality can be juxtaposed. At this time, adjacent concentrating chambers can be shared between adjacent cell sets. The EDI apparatus shown in FIG. 6 is an apparatus shown in FIG. 4 in which a plurality of cell sets are arranged in this manner. The anion exchange membrane 32, the desalting chamber 23, the cation exchange membrane 33, and the concentrating chamber 24 are each 1 As one cell set, N cell sets are arranged between the enrichment chamber 22 and the cathode chamber 25 closest to the anode chamber 21. Here, N is an integer of 1 or more. The anode chamber 21 is filled with a cation exchange resin (CER), the concentration chambers 22, 24 and the cathode chamber 25 are filled with an anion exchange resin (AER), and the desalting chamber 23 is filled with an anion exchange resin and a cation exchange resin. Is filled with mixed bed (MB). Instead of supplying water to the anode chamber 21 from the outside, the outlet water of the cathode chamber 25 is supplied to the anode chamber 21. Moreover, unlike what was shown in FIG. 4, the flow direction of the water in the desalination chamber 23 is a countercurrent with respect to the flow direction of the water in the concentration chambers 22 and 24 of the both sides.

  FIG. 7 shows yet another form of an EDI device according to the present invention. This EDI apparatus is the same as that shown in FIG. 4 except that an anion exchange resin is disposed in a region near the inlet of water to be treated in the desalting chamber 23 and an anion exchange resin is disposed in a region near the outlet. A cation exchange resin is provided in a mixed bed. As a matter of course, the anion exchange membrane 32, the desalting chamber 23, the cation exchange membrane 33, and the concentration chamber 24 constitute one cell set, and this cell set is composed of the concentration chamber 22 and the cathode closest to the anode chamber 21. N pieces can be arranged between the chambers 25. Here, N is an integer of 1 or more.

  The EDI apparatus shown in FIG. 8 is the same as that shown in FIG. 7, but the desalting chamber 23 is divided into four regions according to the flow direction of the water therein, and In order from the position, the ion exchange resin is arranged in each region so as to line up with the cation exchange resin, the anion exchange resin, the cation exchange resin, and the anion exchange resin. That is, the EDI apparatus shown in FIG. 8 is provided with an ion exchanger having a multi-layer bed structure in which the cation exchange resin layers and the anion exchange resin layers are alternately arranged in the water flow direction in the desalting chamber 23. is there. Further, in the EDI apparatus shown in FIG. 8, the flow direction of water in the desalting chamber 23 is different from that shown in FIG. 7 with respect to the flow direction of water in the concentration chambers 22 and 24 on both sides thereof. It is countercurrent.

  The EDI apparatus shown in FIG. 9 is the same as that shown in FIG. 7, but the desalting chamber 23 is divided into three regions according to the flow direction of water therein, In order from the position, the ion exchange resin is arranged in each region so as to line up with the anion exchange resin, the cation exchange resin, and the anion exchange resin. In the EDI apparatus shown in FIG. 9 as well, the ion exchanger in the desalting chamber 23 has a multilayer bed configuration.

  In the EDI apparatus according to the present invention, an intermediate ion exchange membrane (IIEM) is provided between the anion exchange membrane facing the anode and the cation exchange membrane facing the cathode in each desalting chamber, The desalination chamber is divided into a first small desalination chamber and a second small desalination chamber, and water to be treated is placed in one of the first small desalination chamber and the second small desalination chamber. The first and second small desalting chambers can be communicated so that the water supplied and flowing out from one small desalting chamber flows into the other small desalting chamber. As the intermediate ion exchange membrane, both an anion exchange membrane and a cation exchange membrane can be used. At this time, if the small desalting chamber closer to the anode is the first small desalting chamber and the small desalting chamber closer to the cathode is the second small desalting chamber, the first small desalting chamber has at least an anion. The exchanger is filled, and the second small desalting chamber is filled with at least a cation exchanger. The catalyst particles are directed to the ion exchanger in each small desalting chamber, the intermediate ion exchange membrane, the anion exchange membrane provided on the side facing the anode of the first small desalting chamber, and the cathode of the second small desalting chamber. It is adsorbed on at least one of the cation exchange membranes provided on the opposite side.

  FIG. 10 shows an example of an EDI apparatus in which a desalting chamber is partitioned into two small desalting chambers by an intermediate ion exchange membrane. This EDI apparatus has a configuration in which each desalting chamber 23 in the EDI apparatus shown in FIG. 6 is divided into a first small desalting chamber 26 and a second small desalting chamber 27 by an intermediate ion exchange membrane 36. In this example, an anion exchange membrane is used as the intermediate ion exchange membrane 36. The first small desalting chamber 26 closer to the anode 11 is filled with an anion exchange resin, and the second small desalting chamber 27 closer to the cathode 12 is filled with a cation exchange resin. First, the water to be treated is supplied to the second small desalination chamber 27, and the outlet water from the second small desalination chamber 27 is in parallel with the flow of water in the second small desalination chamber 27. 1 small desalting chamber 26 is supplied, and deionized water is obtained from the first small desalting chamber 26 as treated water. The flow of water in the anode chamber 21, the concentration chambers 22, 24, and the cathode chamber 25 is countercurrent to the flow of water in the first and second small desalting chambers 26, 27.

  FIG. 11 schematically shows a water dissociation reaction by catalyst particles in the EDI apparatus shown in FIG. Here, it is assumed that the catalyst particles 43 are adsorbed on the intermediate ion exchange membrane 36 which is an anion exchange membrane. When the cation exchanger 41 and the intermediate ion exchange membrane 36 form an interface of a different ion exchange material, as shown in the figure, the dissociation of water at the interface is promoted, and the intermediate ion exchange membrane 36 Hydroxide ions are efficiently generated on the side and hydrogen ions are efficiently generated on the cation exchanger 41 side.

  FIG. 12 shows another example of the EDI apparatus in which the desalting chamber is partitioned into two small desalting chambers by the intermediate ion exchange membrane. In this EDI apparatus, each desalination chamber 23 in the EDI apparatus shown in FIG. 7 is divided into a first small desalination chamber 26 closer to the anode 11 and a second small desalination closer to the cathode 12 by the intermediate ion exchange membrane 36. The first small desalting chamber 26 is filled with an anion exchange resin, and the second small desalting chamber 27 is filled with an anion exchange resin and a cation exchange resin in a mixed bed. It is. The water to be treated is supplied to the first small desalting chamber 26, the outlet water of the first small desalting chamber 26 is sent to the second small desalting chamber 27, and deionized water is obtained from the second small desalting chamber 27. It is done. For example, an anion exchange membrane is used as the intermediate ion exchange membrane 36.

  The EDI apparatus shown in FIG. 13 does not provide an anion exchange resin and a cation exchange resin in a mixed bed in the second small desalination chamber 27 of the EDI apparatus shown in FIG. The cation exchange resin is disposed in a region close to the region, and the anion exchange resin is disposed in a region close to the outlet.

  Hereinafter, the present invention will be described in more detail based on examples and comparative examples. In the examples and comparative examples, the deionized water production system or EDI apparatus having the above-described configuration was assembled, and the deionized water production system or EDI apparatus was actually operated. In these Examples and Comparative Examples, the effect of the present invention depending on whether or not catalyst particles are used was confirmed by selecting whether or not to use catalyst particles during assembly.

[Example 1 and Comparative Example 1]
The EDI apparatus used in Example 1 and Comparative Example 1 is the same as the EDI apparatus shown in FIG. 6 except that the anion exchange membrane (AEM) 32, the desalting chamber 23, the cation exchange membrane ( The number of repetitions N of the basic configuration (cell set) including the CEM) 33 and the concentration chamber 24 is 3. The anode chamber 21 is filled with a cation exchange resin (CER), the concentration chambers 22, 24 and the cathode chamber 25 are filled with an anion exchange resin (AER), and the desalting chamber 23 is filled with a cation exchange resin and an anion exchange resin. Were mixed in a mixed bed (MB). As the cation exchange resin, Amberlite (registered trademark) IR120B (made by Dow Chemical Co., Ltd.), which is a styrene-based strongly acidic cation exchange resin having a sulfonic acid group as an ion exchange group, an apparent density reference value: about 840 g / L. ) And an anion exchange resin, Amberlite (registered trademark) IRA402BL (made by Dow Chemical Co., Ltd., apparent density) which is a styrenic strong base anion exchange resin having a quaternary ammonium group as an ion exchange group. (Reference value: about 715 g / L) was used. For the cation exchange membrane, Selemion (registered trademark) CME (manufactured by AGC Engineering) was used, and for the anion exchange membrane, Selemion (registered trademark) AME (manufactured by AGC Engineering) was used. The cation exchange membrane and the anion exchange membrane used here are both heterogeneous ion exchange membranes. Heterogeneous ion exchange membranes are granular ion exchange resins made into fine powders, which are molded into a membrane by hardening with a thermoplastic or thermosetting binder. The mechanical strength is higher than that of homogeneous ion exchange membranes. And generally better. On the other hand, the homogeneous ion exchange membrane is obtained by molding the ion exchange resin itself into a film shape.

  In Comparative Example 1, an anion exchange resin not adsorbing catalyst particles was used in the desalting chamber 23. However, in Example 1, the anion exchange resin was previously treated with catalyst particles by the following treatment method, and the treatment was performed. The latter anion exchange resin was mixed with the cation exchange resin and filled in the desalting chamber 23. In Example 1, as the particles used for the treatment of the anion exchange resin, the anion exchange resin was treated using the particles adsorbed on the anion exchange resin, and as a result, the particles were adsorbed on the surface of the anion exchange resin. In any case, as the ion exchange resin filled in the anode chamber 21, the concentration chambers 22 and 24, and the cathode chamber 25, those not adsorbing particles were used.

  Next, the particles used in Example 1 will be specifically described.

In Example 1, attapulgite, which is a silicate mineral containing magnesium and aluminum, which are polyvalent metals, was used as catalyst particles. When observed with an SEM at a magnification of 20000 times, the particle size range of the attapulgite used in Example 1 was 0.02 to 10 μm. Since attapulgite is a needle-like particle, its major axis was taken as the particle size. When measured with the same SEM image, the range of the minor axis of the used apatalite was 0.01 to 1 μm. The minor axis is the length in the direction perpendicular to the major axis at the center of the major axis. The attapulgite (CAS number: 12174-11-7) used in Example 1 has a general composition formula described as (Mg, Al) ₅ Si ₈ O ₂₀ .4H ₂ O, When the ratio of magnesium to aluminum is converted to the mass ratio of silicon dioxide (SiO ₂ ) magnesium oxide (MgO) and aluminum oxide (Al ₂ O ₃ ), SiO ₂ : MgO: Al ₂ O ₃ = 65: 13: Twelve.

(Method of treating anion exchange resin)
The particles were dispersed in pure water, the anion exchange resin was immersed therein, and then the particles were adsorbed on the surface of the anion exchange resin while stirring. The amount of particles used at this time was 300 mg with respect to 1 L of anion exchange resin. The treated anion exchange resin was thoroughly washed with pure water and drained before use.

The amount of attapulgite adsorbed on the anion exchange resin was 190 mg with respect to 1 L of the anion exchange resin when the amount of attapulgite was quantified using inductively coupled plasma (ICP) emission spectrometry for the treated anion exchange resin. there were. Since the specific gravity of attapulgite is 2.4 g / cm ³ , the ratio of the volume of adsorbed attapulgite to the volume of the anion exchange resin is 0.0079%. The density of the anion exchange resin can vary depending on the water content, but when using the above-mentioned apparent density of 715 g / L, the mass ratio of attapulgite to the anion exchange resin is 0.027% by mass.

  The specifications of the EDI apparatus in Example 1 and Comparative Example 1, and the operating conditions such as the water flow rate, the applied voltage, and the quality of the supplied water are as follows. In the following description, the flow rate of water to be treated is the total amount of water to be treated supplied to the plurality of desalting chambers 23 in the EDI apparatus, and the flow rates of the electrode chambers are supplied to the anode chamber 21 and the cathode chamber 25. The concentration water flow rate is the sum of the flow rates of the supply water supplied to the plurality of concentration chambers 22, 24.

Desalination chamber: Dimensions 300 × 100 × 10 mm Mixed bed (MB) filling (volume ratio: cation exchange resin / anion exchange resin = 1/1)
・ Concentration chamber: Dimensions 300 × 100 × 5 mm Anion exchange resin (AER) filling ・ Anode chamber: Dimensions 300 × 100 × 4 mm Cation exchange resin (CER) filling ・ Cathode chamber: Dimensions 300 × 100 × 4 mm Anion exchange resin (AER) Filling ・ Processed water flow rate: 180L / h
・ Concentrated water flow: 30 L / h
-Electrode water flow rate: 10L / h
・ Supply water and treated water: Reverse osmosis membrane (RO) permeate, conductivity 5 ± 1 μS / cm
-Applied current value: 0.9A
Applied current density: 0.3 A / dm ²
About the apparatus of Example 1 and Comparative Example 1, the operation | movement of 1000 hours on the said conditions was performed, and the operating voltage and the specific resistance of the obtained deionized water were compared. The results are shown in Table 1.

  Comparing Example 1 with Comparative Example 1 that does not use catalyst particles, Example 1 clearly has better operating voltage and water quality, so the basic effect of the present invention was confirmed.

  In Example 1, the catalyst particles were adsorbed to the anion exchange resin used in the desalting chamber, but the catalyst was further added to all or part of the ion exchange resin used in each electrode chamber and concentration chamber constituting the EDI apparatus. Particles may be adsorbed.

[Examples 2-1 and 2-2 and Comparative Example 2]
The EDI apparatus used in Examples 2-1 and 2-2 and Comparative Example 2 is the same as the EDI apparatus shown in FIG. 10 except that the anion exchange membrane 32 and the first demineralization chamber 26 between the anode chamber 21 and the cathode chamber 25 are used. The number of repetitions N of the basic configuration (cell set) including the intermediate ion exchange membrane (IIEM) 36, the second small desalting chamber 27, the cation exchange membrane 33 and the concentration chamber 24 is set to 3. The anode chamber 21 and the second small desalting chamber were filled with a cation exchange resin, and the concentration chambers 22, 24, the first small desalting chamber 26 and the cathode chamber 25 were filled with an anion exchange resin. An anion exchange membrane was used as the intermediate ion exchange membrane 36 that partitions the first small desalting chamber 26 and the second small desalting chamber 27. The same anion exchange resin, cation exchange resin, anion exchange membrane and cation exchange membrane as those used in Example 1 were used. However, catalyst particles are not adsorbed to the anion exchange resin. In particular, in Examples 2-1 and 2-2, the catalyst particles referred to in the present invention were previously adsorbed on the anion exchange membrane by the following treatment method, and the anion exchange membrane on which the catalyst particles were adsorbed was used as the intermediate ion exchange membrane 36. It was. The anion exchange membranes 32 and 34 and the cation exchange membranes 31 and 33 are not adsorbed with catalyst particles. As the catalyst particles, attapulgite having the same standard as that used in Example 1 was used. In Comparative Example 2, the catalyst particles are not adsorbed on the anion exchange membrane.

(Treatment method of anion exchange membrane)
0.2 g of catalyst particles were dispersed in 1 L of pure water, and the anion exchange membrane was immersed therein, and then the catalyst particles were adsorbed on the surface of the anion exchange membrane while stirring. The treated anion exchange membrane was thoroughly washed with pure water and drained before use.

  The specifications of the EDI devices in Examples 2-1 and 2-2 and Comparative Example 2, and the operating conditions such as the water flow rate, the applied voltage, and the quality of the supplied water are as follows.

・ First small desalination chamber: dimension 300 × 100 × 10 mm filled with anion exchange resin (AER) ・ Second small desalination chamber: dimension 300 × 100 × 10 mm filled with cation exchange resin (CER) ・ Applied current value: 0.9 A (Example 2-1 and Comparative Example 2), 30A (Example 2-2)
Applied current density: 0.3 A / dm ² (Example 2-1 and Comparative Example 2), 10 A / dm ² (Example 2-2)
The concentration chamber, anode chamber, cathode chamber, treated water flow rate, concentrated water flow rate, electrode water flow rate, supply water, and treated water were the same as in Example 1.

  About the apparatus of Examples 2-1 and 2-2 and the comparative example 2, the driving | running for 1000 hours was performed on the said conditions, and the operating voltage and the specific resistance of the obtained deionized water were compared. The results are shown in Table 2.

When Example 2-1 and Comparative Example 2 were compared, since Example 2-1 had better operating voltage and water quality, the desalination chamber was partitioned into two small desalination chambers by an intermediate ion exchange membrane. It was confirmed that even with the configuration of the EDI apparatus, the effect of the present invention can be obtained as in the case where the desalting chamber is not partitioned. Furthermore, it was confirmed that the same effect can be obtained by adsorbing the catalyst particles not only to the ion exchanger filled in the desalting chamber but also to an ion exchange membrane that partitions the desalting chamber. Comparing Example 2-2 and Comparative Example 2, since the operation voltage and water quality were better in Example 2-2 despite the high current density of 10 A / dm ² , the current density was at least 0. It can be seen that the remarkable effects of the present invention can be obtained in the range of ^{3 to} 10 A / dm2.

  In the above-mentioned Examples 1, 2-1, 2-2, the results when the catalyst particles are adsorbed on the anion exchange resin or the anion exchange membrane are shown as an example, but the catalyst adsorbed on the cation exchange resin or the cation exchange membrane is shown. It goes without saying that the same effect can be obtained even when particles are selected. In addition, the ion exchange membranes used in the above-described examples are all heterogeneous ion exchange membranes, but it goes without saying that the same effect can be obtained even when a homogeneous ion exchange membrane is used. Further, in the above-described embodiment, the ion exchange membrane subjected to the treatment for adsorbing the catalyst particles is used. However, even if an ion exchange membrane formed using an ion exchange resin in which the catalyst particles are adsorbed in advance is used, the above-described ion exchange membrane is used. Needless to say, the same effects as those shown in the examples can be obtained. The case of using an ion exchange membrane formed by using an ion exchange resin in which catalyst particles are previously adsorbed is also included in the scope of the present invention.

  Similarly, in Examples 2-1 and 2-2 described above, among the anion exchange membranes used in the EDI apparatus, a catalyst is formed on the entire surface of the intermediate ion exchange membrane that further partitions the desalination chamber into small desalting chambers. Although the particles are adsorbed, the catalyst particles may be adsorbed to other ion exchange membranes by the EDI apparatus, and the catalyst particles are adsorbed only on one side of the ion exchange membrane or a specific portion of the ion exchange membrane. May be. In particular, in Examples 2-1 and 2-2, an anion exchange membrane was selected as an intermediate ion exchange membrane for partitioning a desalination chamber into small desalting chambers, but the present invention is also applicable when a cation exchange membrane is used as an intermediate ion exchange membrane. Needless to say, the effects of the invention can be obtained. In that case, it is possible to appropriately select whether the catalyst particles are adsorbed on the cation exchange membrane or whether the catalyst particles are adsorbed on the anion exchange resin filled in any of the small desalting chambers.

[Example 3 and Comparative Example 3]
Example 3 and Comparative Example 3 have the same configuration as the EDI apparatus of Example 1 and Comparative Example 1, and the dimensions of the desalination chamber, the concentration chamber, the anode chamber, and the cathode chamber and the ion exchange resin filled in them are also implemented. The same EDI apparatus as in Example 1 but with the cell set repetition count N set to 1 was used. In the apparatus of Example 3, the catalyst particles used were of the same standard as those used in Example 1, and the treatment method of the anion exchange resin was also the same as in Example 1.

  Pure water having a conductivity of 1 μS / cm or less was used as the water to be treated and the supply water, the water flow to be treated was set to 60 L / h, the flow rate of concentrated water was set to 10 L / h, and the flow rate of electrode water was set to 10 L / h. . And the voltage was applied to the EDI apparatus so that it might become the applied current density shown in the column of the applied current density of Table 3, and the operating voltage when 1 hour passed was calculated | required. The results are shown in Table 3. In Table 3, the arrow indicates the behavior of the voltage at the time of measurement, the right arrow (→) indicates a stable tendency, and the upward arrow (↑) indicates an upward tendency. The behavior of the voltage indicated by the arrow is the same in the following tables.

  From the results of Example 3 and Comparative Example 3, if the conductivity of the water to be treated is small, a tendency to increase the operating voltage appears in Comparative Example 3, and if the treatment with the catalyst particles is not performed, the operating voltage increases remarkably. It has been found that operation at a practical applied current density cannot be performed.

[Example 4 and Comparative Example 4]
Amber, which is the same EDI apparatus as in Example 3 and Comparative Example 3, but is a styrenic strong basic anion exchange resin having a quaternary ammonium group as an ion exchange group as an ion exchanger filled in a desalting chamber Only Light (registered trademark) IRA402BL (manufactured by Dow Chemical Co., Ltd., apparent density reference value: about 715 g / L) was used, and the desalting chamber was configured as a single bed. About the anion exchange resin used in Example 4, the same process as the method demonstrated in Example 1 was performed previously, and the apatalite was made to adsorb | suck to the surface. The same water as in Example 3 is used as the water to be treated and the supply water, the flow rate of water to each chamber is the same as in Example 3, and the EDI is set to the applied current density shown in the column of applied current density in Table 4. A voltage was applied to the apparatus, and the operating voltage at the time when 1 hour had elapsed was determined.

  From the results of Example 4 and Comparative Example 4, compared with the case where the mixed bed ion exchange resin is filled in the desalting chamber as in Examples 1 and 3, the catalyst particles are more charged when the single bed ion exchange resin is filled. It has been found that the effect of adsorbing is particularly increased.

[Example 5]
The deionized water production system shown in FIG. 1 was assembled. As the EDI apparatus provided in the deionized water production system, the EDI apparatus used in Example 2-1 with a cell set repetition number N of 5 was used. The ion exchange resin and ion exchange membrane used, the dimensions of each chamber, etc. were the same as in Example 2-1, but no catalyst particles were adsorbed on the ion exchange membrane. Instead, attapulgite is adsorbed in advance to the anion exchange resin used in the EDI apparatus by the same method as shown in Example 1, and an intermediate ion exchange membrane that was an anion exchange membrane in Example 2-1 was used. Changed to a cation exchange membrane. With this configuration, the water dissociation reaction can be promoted between the anion exchange resin adsorbing the attapulgite in the first small desalting chamber and the intermediate ion exchange membrane. In Example 5, the permeated water that passed through the two-stage reverse osmosis membrane device is used as the water to be treated in the EDI device, the conductivity is 2 ± 1 μS / cm, and the sodium concentration is 100 μg / L. The silica concentration was 50 μg / L. As the feed water, reverse osmosis membrane permeated water was used.

The water quality and operating voltage of deionized water flowing out from the EDI device with the treated water flow rate of 800 L / h, the concentrated water flow rate of 80 L / h, the electrode water flow rate of 20 L / h, and the applied current density of 0.5 A / dm ^2. And asked. The results are shown in Table 5.

  From the results of Example 5, the current density in the EDI apparatus is increased even when treated water with low residual ion concentration and low conductivity is used, such as permeated water that has passed through the two-stage reverse osmosis membrane apparatus. It has become possible to increase the flow rate of the water to be treated. When compared with the flow rate of water to be treated per cell set in the EDI apparatus, the flow rate in Example 5 is 2.67 times the flow rate in Example 2.

[Example 6]
The deionized water production system shown in FIG. 3 was assembled. In this deionized water production system, two EDI apparatuses 10 and 15 connected in series are used, and the same EDI apparatus as that described in Example 5 was used for both EDI apparatuses 10 and 15. By providing the membrane permeation devices 51 and 52 connected in two stages and using the two-stage EDI apparatuses 10 and 15, the water to be treated supplied to the second-stage EDI apparatus 10 has a specific resistance. Was 16 ± 2 MΩ · cm (that is, the conductivity was 0.0635 ± 0.008 μS / cm), and the conductivity was extremely small, and the boron concentration was 1 ± 0.2 μg / L. Reverse osmosis membrane permeated water is used as the supply water for the first-stage EDI apparatus 15, and the treated water of the first-stage EDI apparatus 15 is used as the supply water for the second-stage EDI apparatus 10, that is, the first-stage EDI apparatus 15. Deionized water from the EDI unit 15 was used.

The treated water flow rate in the first stage EDI device 15 is 570 L / h, the concentrated water flow rate is 50 L / h, the electrode water flow rate is 20 L / h, and the treated water flow rate in the second stage EDI device 10 is 500 L / h. The concentrated water flow rate was 50 L / h, and the electrode water flow rate was 20 L / h. The applied current density in the EDI apparatuses 10 and 15 was both 0.8 A / dm ² , and the water quality and boron concentration of the deionized water flowing out from the second-stage EDI apparatus 10 and the operating voltage were determined. The results are shown in Table 6.

  When two stages of EDI apparatuses are connected to obtain deionized water having an extremely low impurity concentration, the conductivity of the water to be treated supplied to the second stage EDI apparatus is low, so the second stage EDI apparatus Although it is feared that the operating voltage increases, the results of Example 6 show that the increase in the operating voltage can be suppressed by using the EDI device according to the present invention. Based on the present invention, higher-purity deionized water can be easily obtained. Boron is known as an element that is difficult to remove by ordinary desalting treatment, but according to Example 6, it was found that boron can be removed to the order of ng / L.

[Example 7]
The deionized water production system shown in FIG. 1 was assembled. As the EDI apparatus provided in the deionized water production system, the EDI apparatus shown in FIG. The desalting chamber was configured as a multilayer bed so that the cation exchange resin layer, the anion exchange resin layer, the cation exchange resin layer, and the anion exchange resin layer were arranged in this order from the upstream side along the flow of the water to be treated. The ion exchange membrane and ion exchange resin used were the same as those in Example 1. Apatalite was adsorbed in advance on the anion exchange resin by the same treatment method as in Example 1. The dimensions of the desalting chamber, the concentration chamber, the anode chamber, and the cathode chamber are the same as those in the first embodiment. In Example 7, the permeated water that passed through the two-stage reverse osmosis membrane device was used as the water to be treated in the EDI device, and its conductivity was 1.5 ± 0.2 μS / cm. As the feed water, reverse osmosis membrane permeated water was used.

When the treated water flow rate was 1000 L / h, the concentrated water flow rate was 100 L / h, the electrode water flow rate was 20 L / h, the applied current density was 0.6 A / dm ² , and the operating voltage after 1000 hours of operation was measured. 18V.

  When Example 1 was compared with Example 7, the operating voltage per cell set was 4.0 V in Example 1 and 3.6 V in Example 7. Although the current density in Example 7 is twice the current density in Example 1, and the conductivity of the water to be treated is lower in Example 7, the operating voltage per cell set is in Example. 7 is lower than that of Example 1 because the ion exchanger in the desalting chamber has a multi-layered structure rather than a mixed-bed structure to adsorb the apatalite to the anion exchange resin. It is shown that a remarkable effect can be obtained. Further, when compared with the flow rate of water to be treated per cell set of the EDI apparatus, the flow rate in Example 7 is 3.33 times the flow rate in Example 1.

10,15 Electric deionized water production equipment (EDI equipment)
DESCRIPTION OF SYMBOLS 11 Anode 12 Cathode 51,52 Reverse osmosis membrane apparatus 21 Anode chamber 22,24 Concentration chamber 26 First small desalination chamber 27 Second small desalination chamber 23 Desalination chamber 25 Cathode chamber 31, 33 Cation exchange membrane (CEM)
32, 34 Anion exchange membrane (AEM)
36 Intermediate ion exchange membrane (IIEM)
41 Cation exchanger 42 Anion exchanger 43 Catalyst particles

Claims (26)

A deionized water production system in which raw water is supplied to produce deionized water,
A reverse osmosis membrane device to which raw water is supplied;
An electric deionized water production apparatus having a demineralization chamber partitioned by an ion exchange membrane and supplied with permeate of the reverse osmosis membrane device;
With
The inside of the desalting chamber is filled with an ion exchanger,
A deionized water production system in which particles containing a polyvalent metal are adsorbed on at least one surface of at least part of the ion exchange membrane and at least part of the ion exchanger.   The deionized water production system according to claim 1, wherein the ion exchanger filled in the demineralization chamber is one of an anion exchanger and a cation exchanger.   The deionized water production system according to claim 1, wherein in the desalting chamber, cation exchangers and anion exchangers are alternately arranged along the direction of water flow in the desalting chamber.   The deionized water production system according to any one of claims 1 to 3, wherein each of the reverse osmosis membrane devices has a configuration in which devices each having a reverse osmosis membrane are connected in two stages in series.   The sodium concentration in the permeate supplied to the demineralization chamber of the electric deionized water production apparatus is 100 μg / L or less, and the silica concentration is 50 μg / L or less. Deionized water production system according to item.   The deionized water production system according to any one of claims 1 to 5, wherein a conductivity of the permeated water supplied to the demineralization chamber of the electric deionized water production apparatus is 3 µS / cm or less. An additional electrical deionized water production device is provided between the reverse osmosis membrane device and the electrical deionized water production device,
The permeated water of the reverse osmosis membrane device is supplied to the demineralization chamber of the electric deionized water production device via the demineralization chamber of the additional electric deionized water production device. The deionized water production system according to any one of 6.   8. The deionization apparatus according to claim 7, wherein the electric deionization production apparatus is operated so that a boron concentration in deionized water discharged from the demineralization chamber of the electric deionization production apparatus is 10 ng / L or less. Ionized water production system.   The deionized water production system according to any one of claims 1 to 8, wherein the particles are made of silicate.   The deionized water production system according to claim 9, wherein the particles are made of at least one of aluminum silicate, magnesium silicate, calcium silicate, calcium magnesium silicate, aluminosilicate, and silicate mineral.   The deionized water production system according to claim 10, wherein the particles are made of at least one of attapulgite, sepiolite, and wollastonite. At least one demineralization chamber is provided between an anode chamber having an anode and a cathode chamber having a cathode, and the demineralization chamber is located on the side facing the anode and the side facing the cathode In the electric deionized water production apparatus, the deionization chamber is filled with at least one of an anion exchanger and a cation exchanger.
An apparatus for producing electrical deionized water, wherein particles containing a polyvalent metal are adsorbed on at least one surface of the anion exchange membrane, the cation exchange membrane, the anion exchanger, and the cation exchanger.   The electric deionized water production apparatus according to claim 12, wherein the particles are made of silicate.   The electric deionized water production apparatus according to claim 13, wherein the particles are made of at least one of aluminum silicate, magnesium silicate, calcium silicate, calcium magnesium silicate, aluminosilicate, and silicate mineral. .   The electric deionized water production apparatus according to claim 14, wherein the particles are made of at least one of attapulgite, sepiolite, and wollastonite.   The electric deionized water production apparatus according to any one of claims 12 to 15, wherein the particles are adsorbed on a surface of at least one of the anion exchange membrane and the anion exchanger.   The electric deionized water production apparatus according to any one of claims 12 to 16, wherein at least one of the anion exchange membrane and the cation exchange membrane is a heterogeneous ion exchange membrane.   The electric deionized water production apparatus according to any one of claims 12 to 17, wherein the volume of the particles with respect to the volume of the anion exchanger and the cation exchanger is less than 1% by volume.   The electric deionized water production apparatus according to any one of claims 12 to 18, wherein the demineralization chamber is filled with one of the anion exchanger and the cation exchanger.   In the said desalting chamber, the said anion exchanger and the said cation exchanger are arrange | positioned alternately along the direction of the flow of the water in the said desalting chamber. Electric deionized water production equipment.   The desalting chamber includes an intermediate ion exchange membrane positioned between the anion exchange membrane and the cation exchange membrane, and is partitioned into a first small desalting chamber and a second small desalting chamber by the intermediate ion exchange membrane. The first small desalting chamber defined by the anion exchange membrane and the intermediate ion exchange membrane is filled with at least the anion exchanger, and the second is defined by the cation exchange membrane and the intermediate ion exchange membrane. The small desalting chamber is filled with at least the cation exchanger, and the treated water is supplied to one of the first small desalting chamber and the second small desalting chamber. The first small desalting chamber and the second small desalting chamber communicate with each other so that water flowing out from the small desalting chamber flows into the other small desalting chamber. The electric deionized water production apparatus according to claim 1.   The electric deionized water production apparatus according to claim 21, wherein the particles are adsorbed on the surface of the intermediate ion exchange membrane. In the manufacturing method of the deionized water which uses an electric deionized water manufacturing apparatus in any one of Claims 12 thru | or 22,
Water to be treated is allowed to flow into the desalting chamber while applying the DC voltage between the anode and the cathode so that the current density in the desalting chamber is 0.3 A / dm ² or more and 10 A / dm ² or less. To obtain deionized water. At least one demineralization chamber is provided between an anode chamber having an anode and a cathode chamber having a cathode, and the demineralization chamber is located on the side facing the anode and the side facing the cathode In the method for producing deionized water using an electric deionized water production apparatus, which is partitioned by a cation exchange membrane located in the deionization chamber and at least one of an anion exchanger and a cation exchanger is filled in the demineralization chamber,
Adsorbing particles containing a polyvalent metal on at least one surface of the anion exchange membrane, the cation exchange membrane, the anion exchanger, and the cation exchanger;
After the adsorbing step, deionized water is obtained by flowing water to be treated into the desalting chamber while applying a DC voltage between the anode and the cathode;
A process for producing deionized water, comprising: Used in an electric deionized water production apparatus comprising at least one demineralization chamber filled with at least one of an anion exchanger and a cation exchanger between an anode chamber having an anode and a cathode chamber having a cathode. An anion-exchange membrane that is positioned on the side facing the anode in the desalting chamber and partitions the desalting chamber; a cation that is positioned on the side facing the cathode in the desalting chamber and partitions the desalting chamber In an ion exchange membrane that is at least one of an exchange membrane and an intermediate ion exchange membrane that further partitions the desalting chamber into small desalting chambers,
An ion exchange membrane for an electrical deionized water production apparatus, wherein particles containing a polyvalent metal are adsorbed on the surface of the ion exchange membrane. At least one demineralization chamber is provided between an anode chamber having an anode and a cathode chamber having a cathode, and the demineralization chamber is located on the side facing the anode and the side facing the cathode An ion exchanger that is used in an electric deionized water production apparatus partitioned by a cation exchange membrane located at a position and includes at least one of an anion exchanger and a cation exchanger, and is filled in the demineralization chamber.
An ion exchanger for an electrical deionized water production apparatus, wherein particles containing a polyvalent metal are adsorbed on the surface of the ion exchanger.

Images