JP2013052365A - Electric deionized water making apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of scale in both an ion exchanging membrane and a To prevent generation of scale in both ion exchanging membranes and a negative electrode.SOLUTION: An electric deionized water making apparatus has an negative electrode chamber E1 where the negative electrode 2 is arranged, a positive electrode chamber E2 where a positive electrode 3 is arranged, a plurality of condensing chambers C arranged between the negative electrode chamber E1 and the positive electrode chamber E2, and at least one desalinating chamber D1, the negative electrode chamber E1 is formed between the negative electrode 2 and an anion exchanging membrane a1 facing the negative electrode 2, the condensing chamber C1 are formed between the anion exchanging membrane a1 and a cation exchanging membrane c1 facing the anion exchanging membrane a1, the condensing chamber C2 serving also as the positive electrode chamber E2 is formed between the positive electrode 3 and the anion exchanging membrane a2 facing the positive electrode 3, the desalinating chamber D1 is next to the condensing chamber C2 via the anion exchanging membrane a2, the deionized chamber D1 is filled with an anion exchanging body, water from which cation components are removed in advance is fed to the condensing chamber C2, and water having passed through the condensing chamber C2 is fed to the negative electrode chamber E1 as electrode water.

Description

  The present invention relates to an electric deionized water production apparatus.

Conventionally, a deionized water production apparatus that performs deionization by passing water to be treated through an ion exchanger is known. In such a deionized water production apparatus, when the ion exchange group of the ion exchanger is saturated and the desalting performance is lowered, it is necessary to regenerate the ion exchange group with a chemical (acid or alkali). Specifically, H ⁺ and OH of adsorbed derived anion and cation an acid or an alkali to an ion exchange group ^- has to be replaced with. In recent years, in order to eliminate the disadvantages in operation as described above, an electric deionized water production apparatus that does not require regeneration with a drug has been developed and put into practical use. Hereinafter, the electric deionized water production apparatus may be abbreviated as “EDI”.

  EDI is a device that combines electrophoresis and electrodialysis. The basic configuration of general EDI is as follows. That is, EDI has a pair of concentrating chambers disposed between the opposing cathode chamber and the anode chamber, and a desalting chamber disposed between the pair of concentrating chambers. Furthermore, the desalting chamber has an anion exchange membrane and a cation exchange membrane arranged opposite to each other, and an ion exchanger (anion exchanger and cation exchanger) filled between the exchange membranes.

In order to produce deionized water with EDI having the above-described configuration, water to be treated is passed through the desalting chamber in a state where a DC voltage is applied between the electrodes provided in the anode chamber and the cathode chamber, respectively. . In the desalting chamber, anion components (Cl ⁻ , CO ₃ ²⁻ , HCO ₃ ⁻ , SiO _2, etc.) are obtained by the anion exchanger, and cation components (Na ⁺ , Ca ²⁺ , Mg ^2+, etc.) are obtained by the cation exchanger. Each is adsorbed (captured). At the same time, a water dissociation reaction occurs at the interface between the anion exchanger and cation exchanger in the desalting chamber, and hydrogen ions and hydroxide ions are generated (H ₂ O → H ⁺ + OH ⁻ ). The ion component trapped in the ion exchanger is exchanged with these hydrogen ions or hydroxide ions and released from the ion exchanger. The liberated ion component travels through the ion exchanger to the ion exchange membrane (anion exchange membrane or cation exchange membrane), is electrodialyzed on the ion exchange membrane, and moves to the concentration chamber. The ion component that has moved to the concentration chamber is discharged out of the system together with the concentrated water flowing through the concentration chamber.

  As described above, in EDI, hydrogen ions and hydroxide ions continuously act as an acid or alkali regenerator for regenerating the ion exchanger. For this reason, regeneration by a medicine is basically unnecessary, and continuous operation is possible.

  An example of the configuration of conventional EDI is shown in FIG. The EDI shown in FIG. 6 includes two desalting chambers D1 and D2. The desalting chamber D1 is disposed between the pair of concentration chambers C1 and C2. The desalting chamber D2 is disposed between the pair of concentration chambers C2 and C3. In the EDI shown in FIG. 6, the concentration chamber C1 also serves as the cathode chamber E1, and the concentration chamber C3 also serves as the anode chamber E2.

  The concentrating chamber C1 (cathode chamber E1) and the desalting chamber D1 are partitioned by the first cation exchange membrane c1, and the desalting chamber D1 and the concentrating chamber C2 are partitioned by the first anion exchange membrane a1. ing. The concentration chamber C2 and the desalting chamber D2 are partitioned by the second cation exchange membrane c2, and the desalting chamber D2 and the concentration chamber C3 (anode chamber E2) are separated by the second anion exchange membrane a2. It is partitioned.

  Further, the desalting chambers D1 and D2 are filled with an anion exchanger A and a cation exchanger K, and the concentration chamber C1 (cathode chamber E1) and the concentration chamber C2 are filled with an anion exchanger. The concentration chamber C3 (anode chamber E2) is filled with a cation exchanger.

  In the EDI shown in FIG. 6, a part of water (hereinafter sometimes referred to as “raw water”) that has passed through an RO (Reverse Osmosis) membrane is supplied to the desalting chambers D1 and D2 as treated water. Moreover, the other part of raw | natural water is each supplied to concentration chamber C1, C2, C3 as concentrated water. Of course, the raw water supplied to the concentrating chambers C1 and C3 is also used as electrode water.

Here, when a DC voltage is applied between the cathode 2 in the cathode chamber E1 and the anode 3 in the anode chamber E2, hydroxide ions are generated in the cathode chamber E1 by electrolysis of water (electrode reaction). Since it is generated (2H ₂ O + 2e ⁻ → H ₂ + 2OH ⁻ ), the liquidity of the water (electrode water / concentrated water) flowing through the cathode chamber E1 tends to be alkaline. Then, the hardness component attracted to the cathode 2 reacts with hydroxide ions, and a scale (mainly magnesium hydroxide) is generated on the surface of the cathode 2.

  In addition, the hydroxide ions generated in the cathode chamber E1 are attracted to the anode side and gather on the surface of the cation exchange membrane c1. On the other hand, the cation component moves from the adjacent desalting chamber D1 to the cathode chamber E1, which also functions as a concentration chamber. As a result, a scale is also generated on the cathode side surface of the cation exchange membrane c1.

  That is, in the EDI configured as shown in FIG. 6, scales are generated in both the cathode and the cation exchange membrane closest to the cathode. When the scale is generated, not only the electric resistance at the generation point increases and the power consumption increases, but also the current distribution becomes non-uniform and the quality of the treated water decreases.

  For the purpose of solving the above problems, an EDI configured as shown in FIG. 7 has been proposed (Patent Document 1). In the EDI shown in FIG. 7, water that has passed through the anode chamber E2 is supplied to the cathode chamber E1 as electrode water and concentrated water. An anion component flows from the adjacent desalting chamber D2 into the anode chamber E2, which also functions as a concentration chamber, and is concentrated. Therefore, the liquidity of the water that has passed through the anode chamber E2 tends to be acidic. That is, by supplying acidic water to the cathode chamber E1 which has an alkaline tendency, the liquidity is neutralized and the generation of the scale is suppressed.

JP 2001-058186 A

  However, in the cathode chamber of EDI, a large amount of hydroxide ions is always generated by electrolysis of water. The same applies to the cathode chamber E1 shown in FIG. Therefore, even if the liquidity of the water supplied to the cathode chamber E1 is acidic, there is a high possibility that the surface of the cathode 2 is locally alkaline. Although scale on the ion exchange membrane can be avoided by supplying acidic electrode water, it is insufficient to neutralize the alkalinity of the cathode surface. In addition, in the cathode chamber E1 which also functions as a concentration chamber, hardness components (magnesium ions and calcium ions trapped in the adjacent desalting chamber D1 are concentrated to a high concentration. Therefore, they are attracted to the cathode 2. There is a possibility that a part of the hardness component reacts with hydroxide ions and a scale is generated on the surface of the cathode 2.

  An object of the present invention is to reliably prevent scale generation not only on an ion exchange membrane but also on an electrode.

  The electric deionized water production apparatus of the present invention includes a cathode chamber provided with a cathode, an anode chamber provided with an anode, a plurality of concentration chambers provided between the cathode chamber and the anode chamber, and at least one And a desalination chamber. The space between the cathode and the anode is partitioned into a plurality of spaces by a plurality of ion exchange membranes. A cathode chamber is formed by a space between the cathode and the first anion exchange membrane facing the cathode. A first concentration chamber adjacent to the cathode chamber is formed by a space between the first anion exchange membrane and the first cation exchange membrane facing the first anion exchange membrane. A second concentrating chamber that also serves as the anode chamber is formed by a space between the anode and the second anion exchange membrane facing the anode. The desalting chamber is adjacent to the second concentration chamber that also serves as the anode chamber via the second anion exchange membrane. Furthermore, the desalting chamber is filled with at least an anion exchanger. Further, water from which the cation component has been removed in advance is supplied to the second concentration chamber that also serves as the anode chamber. And the water which passed through the 2nd concentration chamber which serves as an anode chamber is supplied to a cathode chamber as electrode water. The water supplied to the second concentrating chamber that also serves as the anode chamber takes in the anion component that has moved from the desalting chamber in the process of passing through the chamber. Therefore, acidic water containing a large amount of anionic components is supplied to the cathode chamber.

  According to the present invention, scale generation in both the ion exchange membrane and the electrode is prevented.

It is a schematic block diagram which shows an example of embodiment of EDI of this invention. It is a schematic block diagram which shows the other example of embodiment of EDI of this invention. 1 is a schematic configuration diagram of EDI according to Embodiment 1. FIG. 2 is a schematic configuration diagram of EDI according to Example 2 and Comparative Example 2. FIG. It is a schematic block diagram of EDI which concerns on the comparative example 1. It is a schematic block diagram which shows an example of the conventional EDI. It is a schematic block diagram of EDI described in Patent Document 1.

(Embodiment 1)
Hereinafter, an example of an EDI embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of EDI according to the present embodiment. In the EDI according to the present embodiment, a desalination treatment unit including a pair of concentration chambers C1 and C2 and a desalination chamber D1 disposed between the concentration chambers C1 and C2 between the cathode 2 and the anode 3 facing each other. Is provided.

  Here, the anode 3 is provided in the concentration chamber C2. That is, the concentration chamber C2 also serves as the anode chamber E2. On the other hand, the cathode 2 is provided in a cathode chamber E1 which is independent from the concentration chamber C1.

  Each of the above rooms is formed by dividing the inside of the frame 1 into a large number of spaces by a plurality of ion exchange membranes, and is adjacent to each other through the ion exchange membranes. The arrangement of the rooms will be described in order from the cathode chamber E1 side as follows. That is, the cathode chamber E1 is adjacent to the concentration chamber C1 via the first anion exchange membrane a1, and the concentration chamber C1 is adjacent to the desalting chamber D1 via the cation exchange membrane c1. The desalting chamber D1 is adjacent to the concentration chamber C2 (anode chamber E2) via the second anion exchange membrane a2.

  The cathode 2 provided in the cathode chamber E1 is a metal net or plate, for example, a stainless steel net or plate.

The anode 3 provided in the anode chamber E2 is a metal net or plate. The water to be treated Cl ^- if it contains chlorine is generated at the anode. For this reason, it is desirable to use a material having chlorine resistance for the anode, and examples thereof include metals such as platinum, palladium and iridium, or materials obtained by coating titanium with these metals.

  The cathode chamber E1 is filled with the anion exchanger A in a single bed form. On the other hand, the anode chamber E2 (concentration chamber C2) is filled with the cation exchanger K in a single bed form. That is, the cathode chamber E1 is provided with a layer of anion exchanger A (hereinafter “anion layer A”). On the other hand, the anode chamber E2 is provided with a layer of a cation exchanger K (hereinafter “cation layer K”).

  Desalination chamber D1 is filled with anion exchanger A and cation exchanger K in a mixed bed form.

  In addition, in FIG. 1, the frame 1 is shown integrally. However, actually, each room is provided with a separate frame (cell), and these frames are in close contact with each other. The material of the frame 1 is not particularly limited as long as it has insulating properties and does not leak liquid. For example, polyethylene, polypropylene, polyvinyl chloride, ABS, polycarbonate, m-PPE (modified polyphenylene ether), etc. Resins can be mentioned.

  Next, the main flow of the treated water, treated water, concentrated water, and electrode water in the EDI shown in FIG. 1 will be outlined. In addition, also in EDI which concerns on this embodiment, the water which permeate | transmitted RO membrane, ie, raw water, is used.

  A part of the raw water is supplied to the desalting chamber D1 as treated water, and the other part of the raw water is supplied to the concentrating chamber C1 as concentrated water. Part of the water that has passed through the desalting chamber D1 is discharged out of the system as treated water, and the other part is supplied to the anode chamber E2 as electrode water and concentrated water.

  The water supplied to the anode chamber E2 passes through the anode chamber E2, and is then supplied to the cathode chamber E1 as electrode water. The water supplied to the cathode chamber E1 passes through the cathode chamber E2, and is then discharged out of the system together with the concentrated water that has passed through the concentration chamber C1.

  In addition, the water flow direction of the to-be-processed water in the desalting chamber D1 is opposite to the water flow direction of the concentrated water in the concentration chambers C1 and C2.

  As described above, several flow paths are provided for flowing the water to be treated, treated water, concentrated water, and electrode water. 1 has one end connected to the raw water supply port and the other end connected to the inlet of the desalination chamber D1. One end of the channel 11 is connected to the outlet of the desalting chamber D1, and the other end is connected to the outlet of the treated water.

  One end of the channel 12 is connected to the channel 11 and the other end is connected to the inlet of the anode chamber E2 (concentration chamber C2). One end of the flow path 13 is connected to the outlet of the anode chamber E2, and the other end is connected to the inlet of the cathode chamber E. One end of the channel 14 is connected to the outlet of the cathode chamber E1, and the other end is connected to the outlet of the concentrated water.

  One end of the flow path 15 is connected to the raw water inlet, and the other end is connected to the inlet of the concentrating chamber C1. One end of the channel 16 is connected to the outlet of the concentration chamber C <b> 1 and the other end is connected to the channel 14.

  As described above, in the EDI according to the present embodiment, part of the treated water is supplied to the anode chamber E2 (concentration chamber C2) as electrode water and concentrated water. Furthermore, the water that has passed through the anode chamber E2 (concentration chamber C2) is supplied to the cathode chamber E1 as electrode water. In other words, the water supplied to the anode chamber E2 as electrode water / concentrated water is water from which ionic components have been removed and contains almost no hardness component. The water supplied to the anode chamber E2 takes in the anion component that has moved from the desalting chamber D1 to the anode chamber E2 in the process of passing through the anode chamber E2 that also functions as a concentration chamber. Accordingly, the cathode chamber E1 is supplied with water containing a large amount of anionic components and not containing hardness components. In other words, the electrode water supplied to the cathode chamber E1 is acidic water that does not contain a hardness component. In addition, a concentration chamber C1 is adjacent to the cathode chamber E1. The concentration chamber C1 functions to discharge the hardness component moving from the desalting chamber D1 to the outside of the system together with the concentrated water. Therefore, the cathode chamber E1 is not affected by the hardness component moving from the desalting chamber, and the concentration of the hardness component in the cathode chamber E1 is kept low.

  Therefore, even if the surface of the cathode 2 is locally alkaline, scale generation on the surface of the cathode 2 is prevented or reduced.

The anion component in the electrode water supplied to the cathode chamber E1 is captured by the anion exchanger A in the cathode chamber E1 in the process of passing the electrode water through the cathode chamber E1. Therefore, the liquidity of the water that has passed through the cathode chamber E1 is almost neutral.
(Embodiment 2)
Hereinafter, another example of the EDI embodiment of the present invention will be described with reference to the drawings. However, the EDI according to the present embodiment has the same configuration as the EDI according to Embodiment 1 except that the desalination chamber is divided into two small desalination chambers. Therefore, only the configuration different from the EDI according to the first embodiment will be described below, and the description of the common configuration will be omitted as appropriate.

  FIG. 2 is a schematic configuration diagram of EDI according to the present embodiment. As shown in FIG. 2, the EDI desalination chamber D1 according to this embodiment is divided into two small desalination chambers by an ion exchange membrane. Specifically, the desalting chamber D1 is adjacent to the small desalting chamber D1-1 adjacent to the concentrating chamber C1 and the concentrating chamber C2 (anode chamber E2) by the second cation exchange membrane c2. It is divided into a small desalination chamber D1-2. However, the ion exchange membrane that divides the desalting chamber D1 into two small desalting chambers is not limited to a cation exchange membrane, and may be an anion exchange membrane or a bipolar membrane.

  The small desalting chamber D1-1 is filled with a cation exchanger K in a single bed form, and the small desalting chamber D1-2 is filled with an anion exchanger in a single bed form.

  In the EDI according to the present embodiment, a part of raw water is supplied to the small desalination chamber D1-1 as treated water. The water supplied to the small desalting chamber D1-1 is supplied to the small desalting chamber D1-2 as intermediate water after passing through the small desalting chamber D1-1. After the water supplied to the small desalting chamber D1-2 passes through the small desalting chamber D1-2, a part of the water is discharged out of the system as treated water, and the other part as electrode water and concentrated water. It is supplied to the anode chamber E2 (concentration chamber C2). Furthermore, the water that has passed through the anode chamber E2 (concentration chamber C2) is supplied to the cathode chamber E1 as electrode water.

  As described above, also in the EDI according to the present embodiment, water containing a large amount of anionic components and not containing hardness components is supplied to the cathode chamber E1 as electrode water, and further the hardness components heading from the desalting chamber to the cathode. Is prevented by the concentration chamber C1. Therefore, even if the surface of the cathode 2 is locally alkaline, scale generation on the surface of the cathode 2 is prevented or reduced.

From the explanation so far, it is said that acidic water containing no hardness component is supplied to the cathode chamber as electrode water, and the concentration chamber is provided between the cathode chamber and the desalting chamber so that the hardness component does not move from the desalting chamber to the cathode chamber. It should be understood that it is a feature of the present invention. Therefore, a configuration necessary for supplying water having the above liquid property to the cathode chamber and preventing the hardness component from moving from the desalting chamber to the cathode chamber is an essential configuration of the present invention, and other configurations. Can be appropriately changed. For example, the flow path can be changed so that a part of the water (intermediate water) that has passed through the small desalting chamber D1-1 shown in FIG. 2 is supplied to the anode chamber E2. Further, the water to be treated may be passed through the small desalting chamber D1-2 and the small desalting chamber D1-1 in this order. In this case, water that has passed through both the small desalting chamber D1-2 and the small desalting chamber D1-1 may be supplied to the anode chamber E2. Moreover, there is no restriction | limiting in particular in the number of desalination process parts, Two or more desalination process parts can also be provided. Furthermore, the type and filling form of the ion exchanger filled in each room can be changed as appropriate. With the change of the ion exchanger filling mode, for example, when the small desalting chamber D1-2 is filled with a cation exchanger, a part of the water (intermediate water) that has passed through the small desalting chamber D1-2 is treated as an anode. You may supply to the chamber E2.
(Comparative test)
In order to confirm the effect of the present invention, the following comparative test was conducted. In this comparative test, four EDIs having any of the configurations shown in FIGS. 3 to 5 were prepared as Examples 1 and 2 and Comparative Examples 1 and 2. In each figure, illustration of some flow paths is omitted.

  The EDI according to Example 1 has the configuration shown in FIG. 3, and the EDI according to Example 2 and Comparative Example 2 has the configuration shown in FIG. Further, the EDI according to Comparative Example 1 has the configuration shown in FIG.

  The EDIs according to Examples 1 and 2 and Comparative Examples 1 and 2 have the same basic configuration as the EDI shown in FIG. 2, but differ from the EDI shown in FIG. 2 in that it includes three desalting units. However, each of the desalting chambers D1 to D3 shown in FIGS. 3 to 5 has the same configuration as the desalting chamber D1 shown in FIG. Each of the concentration chambers C1 to C3 shown in FIGS. 3 and 4 has the same configuration as the concentration chamber C1 shown in FIG. Further, the enrichment chamber C4 (anode chamber E2) shown in FIGS. 3 to 5 has the same configuration as the anode chamber E2 (enrichment chamber C2) shown in FIG. However, the concentration chamber C1 shown in FIG. 5 also serves as the cathode chamber E1, and is different from the concentration chamber C1 shown in FIGS.

  In the EDI according to Example 1 and Comparative Example 1, part of the treated water is supplied to the anode chamber E2 (concentration chamber C4) as electrode water / concentrated water. On the other hand, in the EDI according to the second embodiment, two-stage RO permeated water is supplied to the anode chamber E2 (concentration chamber C4) as electrode water / concentrated water from a supply source (not shown). In EDI according to Comparative Example 2, one-stage RO permeated water is supplied to the anode chamber E2 (concentration chamber C4) as electrode water / concentrated water from a supply source (not shown). In all EDIs, water that has passed through the anode chamber E2 (concentration chamber C4) is supplied to the cathode chamber E1 as electrode water.

The conditions (specifications, flow rate, supply water, etc.) in this comparative test are summarized as follows. CER is an abbreviation for a cation exchanger (cation exchange resin) and AER is an anion exchanger (anion exchange resin).
・ Cathode chamber E1: Dimension 300 × 80 × 4 mm AER filling ・ Anode chamber E2 (concentration chamber C4): Dimension 300 × 80 × 4 mm CER filling ・ Small desalination chamber D1-1: Dimension 300 × 80 × 8 mm CER filling ・ Small Desalination chamber D1-2: Dimensions 300 × 80 × 10 mm AER filling / concentration chambers C1 to C3: Dimensions 300 × 80 × 5 mm AER filling / treatment water flow rate: 150 L / h
・ Concentrated water flow: 15L / h (per room)
・ Electrode water flow rate: 10L / h
・ Desalination chamber supply water: One-stage RO permeated water (11 ± 1 μS / cm)
・ Desalination chamber water hardness: 1 ± 0.1mgCaCO ₃ / L
・ Concentration chamber supply water: One-stage RO permeated water (11 ± 1 μS / cm)
Anode chamber supply water (Example 1, Comparative Example 1): treated water (hardness: <0.001 mg CaCO ₃ / L)
Anode chamber supply water (Example 2): Two-stage RO permeated water (Hardness: 0.2 ± 0.1 mg CaCO ₃ / L)
・ Anode chamber supply water (Comparative Example 2): One-stage RO permeated water (Hardness: 1 ± 0.1 mg CaCO ₃ / L)
-Applied current value: 1.1A
Applied current density: 0.46 A / dm ²
Under the above conditions, Examples 1 and 2 and Comparative Examples 1 and 2 were continuously operated for 2000 hours, and the operating voltage and treated water quality (specific resistance) were measured. The measurement results are shown in Table 1. Moreover, after completion | finish of operation, each apparatus was disassembled and the production | generation state of the scale was confirmed visually. The confirmation results are shown in Table 2.

DESCRIPTION OF SYMBOLS 1 Frame 2 Cathode 3 Anode 10-16 Flow path A Anion exchanger (anion layer)
K cation exchanger (cation layer)
E1 Cathode chamber E2 Anode chamber C1-C4 Concentration chamber D1-D3 Desalination chamber D1-1, D1-2 Small desalination chamber

Claims (7)

An electric desorption having a cathode chamber provided with a cathode, an anode chamber provided with an anode, a plurality of concentration chambers and at least one demineralization chamber provided between the cathode chamber and the anode chamber. An ion water production device,
The space between the cathode and the anode is partitioned into a plurality of spaces by a plurality of ion exchange membranes arranged between the cathode and the anode,
The cathode chamber is formed by a space between the cathode and the first anion exchange membrane facing the cathode,
A space between the first anion exchange membrane and the first cation exchange membrane facing the first anion exchange membrane forms a first concentration chamber adjacent to the cathode chamber,
A second concentration chamber also serving as the anode chamber is formed by a space between the anode and the second anion exchange membrane facing the anode;
The desalting chamber is adjacent to the second concentration chamber serving also as the anode chamber through the second anion exchange membrane,
The desalting chamber is filled with at least an anion exchanger,
The second concentration chamber also serving as the anode chamber is supplied with water from which the cation component has been previously removed,
An electrical deionized water production apparatus in which water that has passed through the second concentration chamber also serving as the anode chamber is supplied to the cathode chamber as electrode water. The electric deionized water production apparatus according to claim 1, wherein a hardness component concentration in the electrode water supplied to the cathode chamber is 0.3 mg CaCO ₃ / L or less.   The electric deionized water production apparatus according to claim 1 or 2, wherein at least a part of the water that has passed through the demineralization chamber is supplied to the second concentration chamber that also serves as the anode chamber. The electric deionized water production apparatus according to any one of claims 1 to 3, wherein the demineralization chamber is filled with both an anion exchanger and a cation exchanger. The desalting chamber is partitioned into two small desalting chambers by an ion exchange membrane;
The first small desalting chamber is filled with at least a cation exchanger,
The second small desalting chamber is filled with at least an anion exchanger,
The second small desalting chamber is adjacent to the second concentration chamber serving also as the anode chamber via the second anion exchange membrane,
The electric deionized water production apparatus according to claim 4, wherein at least a part of the water that has passed through the first small demineralization chamber is supplied to the second concentrating chamber that also serves as the anode chamber.   The at least part of the water that has passed through the second small desalting chamber after passing through the first small desalting chamber is supplied to the second concentrating chamber that also serves as the anode chamber. Electric deionized water production equipment.   The electric deionized water production apparatus according to any one of claims 1 to 6, wherein the cathode chamber is filled with an anion exchanger.

Images