JP7672247B2 - Water treatment method and water treatment device - Google Patents

Description

The present invention relates to a water treatment device and a water treatment method that can remove dissolved oxygen from water.

A membrane degassing method using a degassing membrane is well known as a method for removing dissolved oxygen from water to be treated when the water is treated to produce pure water or the like. However, in the membrane degassing method, it is necessary to maintain a vacuum on the gas phase side, which is the opposite side of the water to be treated, across the degassing membrane, and therefore a vacuum pump or the like is required. Therefore, a method has been put into practical use in which a reducing agent such as hydrogen or hydrazine is added to the water to be treated, and the water is brought into contact with a deoxygenation catalyst carrying palladium or the like, and a reaction is caused to proceed to produce water from the dissolved oxygen and hydrogen (or hydrazine) to remove the dissolved oxygen. Patent Document 1 discloses an example of removing dissolved oxygen by contacting the water with a deoxygenation catalyst in the presence of hydrogen. Patent Document 2 discloses a method using an electrolytic cell in which a cathode chamber and an anode chamber are partitioned by a solid polymer electrode membrane, in which the water to be treated is supplied to the cathode chamber while electrolysis of the water proceeds, and the dissolved oxygen is reduced and removed by a cathode reaction in the cathode chamber, and the dissolved oxygen that could not be removed is brought into contact with a deoxygenation catalyst together with the hydrogen produced by electrolysis to remove the dissolved oxygen.

One of the devices that produces desalted water from treated water is the electrodeionization water production device (EDI (Electrodeionization) device). The EDI device is a device that combines electrophoresis and electrodialysis, and at least the desalting chamber is filled with ion exchange resin. The EDI device has the advantage of eliminating the need for a process to regenerate the ion exchange resin with chemicals. Patent Document 3 discloses that the desalting chamber of the EDI device is filled with a mixture of anion exchange resin and cation exchange resin, and part of the anion exchange resin is made of catalytic resin carrying copper or palladium, and hydrogen is added to the treated water supplied to the desalting chamber, thereby desalting the treated water in the desalting chamber and removing dissolved oxygen from the treated water. Since the cathode water discharged from the cathode chamber of the EDI device contains hydrogen, Patent Document 3 also discloses that the cathode water can be added to the treated water as a hydrogen source. Patent Document 4 discloses that hydrogen peroxide in the water being treated can be decomposed and removed by contacting it with an anion exchange resin carrying platinum, palladium, or the like.

Japanese Patent Application Publication No. 5-96283 Japanese Patent Application Publication No. 7-241569 Japanese Patent Application Publication No. 10-272474 JP 2007-185587 A

The method disclosed in Patent Document 3 is a method that can remove dissolved oxygen from the water being treated while also desalination without requiring a vacuum pump or the like, but it requires a separate mechanism for adding hydrogen to the water being treated. Even if cathode water is added to the water being treated, a pump is required to pressurize the cathode water, since the pressure at the outlet of the cathode chamber is generally lower than the pressure at the inlet of the desalination chamber.

The object of the present invention is to provide a water treatment method and water treatment device that can remove dissolved oxygen and other substances from the water to be treated with a simple configuration.

The inventors of the present invention focused on the cathode chamber, which was not effectively used for desalination treatment in conventional EDI devices (electrodeionized water production devices), and discovered that dissolved oxygen in the water to be treated can be removed by reacting hydrogen generated by a cathode reaction in the cathode chamber with dissolved oxygen in the cathode chamber, thus completing the present invention. In this case, since the purpose is to remove dissolved oxygen, the desalination chamber of the EDI device is not necessarily provided. Therefore, the water treatment method of the present invention is a water treatment method for removing at least dissolved oxygen contained in the water to be treated, and includes a step of applying a direct current between an anode provided in the anode chamber and a cathode provided in a cathode chamber filled with an ion exchanger, and a step of passing the water to be treated through the cathode chamber, and at least a part of the ion exchanger filled in the cathode chamber is an ion exchanger carrying a metal catalyst. In this water treatment method, the step of applying a direct current between the anode and the cathode and the step of passing the water to be treated through the cathode chamber may be performed simultaneously or separately.

The water treatment device of the present invention has an anode chamber equipped with an anode, and a cathode chamber equipped with a cathode and filled with an ion exchanger to which the water to be treated is supplied, and at least a portion of the ion exchanger filled in the cathode chamber is an ion exchanger carrying a metal catalyst, and a direct current is applied between the anode and the cathode.

In the present invention, any metal catalyst can be used as long as it promotes the reaction of producing water from hydrogen and oxygen as the metal catalyst supported on the ion exchanger filled in the cathode chamber. Examples of such metal catalysts include iron, copper, manganese, palladium, platinum, etc. Among them, platinum group metal catalysts not only promote the reduction reaction of oxygen, but also have high catalytic activity for decomposing hydrogen peroxide, so they can be used preferably when hydrogen peroxide is contained in the water to be treated. A platinum group metal catalyst is a catalyst containing one or more metals selected from ruthenium, rhodium, palladium, osmium, iridium, and platinum. The platinum group metal catalyst may contain any of these metal elements alone, or may be a combination of two or more of these. Among these, platinum, palladium, and platinum/palladium alloys have high catalytic activity and are preferably used as platinum group metal catalysts.

In the present invention, it is preferable that the cathode chamber is partitioned by an ion exchange membrane on the anode chamber side. If it is partitioned by an ion exchange membrane, it becomes possible to move ions captured by the ion exchanger in the cathode chamber to the outside of the cathode chamber through the ion exchange membrane, and the ion exchanger in the cathode chamber is regenerated, so that the dissolved oxygen removal performance can be maintained for a long period of time. More specifically, it is preferable that the ion exchanger filled in the cathode chamber is an anion exchanger such as an anion exchange resin, and the ion exchange membrane partitioning the cathode chamber is an anion exchange membrane. By configuring it in this way, anions in the water to be treated, such as carbonate ions and bicarbonate ions, are adsorbed to the anion exchanger, and then the anion exchanger is regenerated with hydroxide ions generated by the electrolysis reaction of water proceeding at the cathode, and the liberated anions move to the outside of the cathode chamber through the anion exchange membrane. As a result, the water to be treated is desalination-treated with respect to anions such as carbonate ions and bicarbonate ions in the cathode chamber. That is, in the cathode chamber, not only the removal of dissolved oxygen but also the decarbonation treatment is performed on the water to be treated.

When the above-mentioned dissolved oxygen removal process is performed in the cathode chamber of a typical EDI device, this removal process proceeds independently of the desalination process in the desalination chamber of the EDI device. Therefore, the water treatment device of the present invention can be easily realized by using an existing EDI device and using an ion exchanger carrying a metal catalyst as the ion exchanger filled in the cathode chamber. In this case, water to be treated other than the water to be treated from which dissolved oxygen is to be removed can be passed through the desalination chamber of the EDI device. Alternatively, the water to be treated after the dissolved oxygen has been removed by passing through the cathode chamber can be passed through the desalination chamber to desalinate the water to be treated.

According to the present invention, by utilizing the cathode chamber in the EDI device, it is possible to remove dissolved oxygen and other substances from the water being treated with a simple configuration.

1 is a diagram showing a water treatment device according to an embodiment of the present invention; FIG. 13 is a diagram showing another example of a water treatment device. FIG. 1 illustrates a water treatment device configured as an EDI device. FIG. 13 is a diagram showing another example of a water treatment device configured as an EDI device. FIG. 13 is a diagram showing another example of a water treatment device configured as an EDI device. 1 is a flow chart showing an example of a water treatment system including a water treatment device. 1 is a flow chart showing another example of a water treatment system including a water treatment device. 1 is a flow chart showing another example of a water treatment system including a water treatment device. 1 is a graph showing the results of Example 1.

Next, a preferred embodiment of the present invention will be described with reference to the drawings. Figure 1 shows the basic configuration of a water treatment device based on the present invention.

This water treatment device includes an anode chamber 21 in which an anode 11 is provided, a concentration chamber 24 separated from the anode chamber 21 by a cation exchange membrane 31, and a cathode chamber 25 in which a cathode 12 is provided and separated from the concentration chamber 24 by an anion exchange membrane 34. The anode chamber 21 is filled with a cation exchange resin (CER) which is a cation exchanger, and the concentration chamber 24 is filled with an anion exchange resin (AER) which is an anion exchanger. The cathode chamber 25 is filled with an ion exchanger carrying a metal catalyst on its surface. In this embodiment, the cathode chamber 25 is filled with a single bed of an anion exchange resin carrying palladium (Pd) on its surface. Water to be treated containing dissolved oxygen is supplied to the cathode chamber 25, and this water to be treated passes through the cathode chamber 25. Supply water is supplied to the concentration chamber 24, and the supply water that has passed through the concentration chamber 24 is supplied directly to the anode chamber 21. The feed water that has passed through the anode chamber 21 is discharged from the anode chamber 21 as wastewater. The feed water is not particularly limited, and may be, for example, water obtained by removing turbidity and oxidizing substances from city water, industrial water, groundwater, etc., and then treating the water with a reverse osmosis membrane device. In the following description, an anion exchange resin with palladium (Pd) supported on its surface is called a Pd-supported anion exchange resin (Pd AER).

In the water treatment device shown in FIG. 1, a direct current is applied between the anode 11 and the cathode 12, and the water to be treated is supplied to the cathode chamber 25 while the feed water is supplied to the concentration chamber 24. In the cathode chamber 25, the direct current causes a cathode reaction on the surface of the cathode 12 to generate hydrogen. This hydrogen reacts with the dissolved oxygen in the water to be treated on the surface of the Pd-supported anion exchange resin (Pd AER), resulting in the generation of water. The amount of dissolved oxygen in the water to be treated decreases by the amount of hydrogen that reacts with it. Since the reaction rate of hydrogen and oxygen is high in the presence of palladium, which is a metal catalyst, if a sufficient amount of hydrogen is generated, treated water from which dissolved oxygen has been sufficiently removed is discharged from the cathode chamber 25. If hydrogen is present in the cathode chamber 25, dissolved oxygen is removed, so the application of a direct current between the anode 11 and the cathode 12 can be performed intermittently, taking into account the residence time of the water to be treated in the cathode chamber 25. Furthermore, the water to be treated may be passed intermittently through the cathode chamber 25 while the direct current is applied continuously or intermittently.

Since the Pd-supported anion exchange resin is an anion exchanger, anions such as carbonate ions (CO ₃ ²⁻ ) and hydrogen carbonate ions (HCO ₃ ⁻ ) in the water to be treated are captured by the Pd-supported anion exchange resin. Since hydroxide ions (OH ⁻ ) are also generated by the cathode reaction at the cathode 12, the anions captured by the Pd-supported anion exchange resin (Pd AER) are ion-exchanged by the hydroxide ions and liberated, and move by the electric field between the anode 11 and the cathode 12, and move through the anion exchange membrane 34 to the concentration chamber 24. The anions that have moved to the concentration chamber 24 are carried by the flow of the supply water in the concentration chamber 24 and are discharged to the outside of the device through the anode chamber 21. That is, the Pd-supported anion exchange resin as an anion exchanger is constantly regenerated in the same way as the ion exchanger in the desalting chamber of a general EDI device, and in the water treatment device of this embodiment, the cathode chamber 25 also performs desalination treatment on the anions.

Since the Pd-loaded anion exchange resin can also decompose hydrogen peroxide, the water treatment device of this embodiment can also remove hydrogen peroxide from the water to be treated. When the Pd-loaded anion exchange resin decomposes hydrogen peroxide, the decomposition products are hydrogen and oxygen. The generated oxygen reacts with hydrogen in the presence of the Pd-loaded anion exchange resin to become water, so the decomposition and removal of hydrogen peroxide does not increase the dissolved oxygen concentration. In addition, in the water treatment device shown in FIG. 1, the anode chamber 21 may also function as the concentration chamber 24. In that case, the cation exchange membrane 31 may be removed, and the anode chamber 21 and the concentration chamber 24 may be integrated into one structure.

Figure 2 shows a water treatment device of another embodiment. The water treatment device shown in Figure 2 is similar to the water treatment device shown in Figure 1, but differs from that shown in Figure 1 in that the cathode chamber 25 has a double-bed configuration and the Pd-loaded anion exchange resin is provided only on the downstream side of the flow in the cathode chamber 25. The upstream side of the flow in the cathode chamber 25 is filled with anion exchange resin (AER) that does not support a metal catalyst. The cathode reaction in the cathode chamber 25 proceeds over the entire surface of the cathode 12, and the reaction rate between hydrogen and oxygen in the presence of the Pd-loaded anion exchange resin is sufficiently high, so that even if the Pd-loaded anion exchange resin is placed only on the outlet side of the cathode chamber 25, dissolved oxygen in the water to be treated can be sufficiently removed. In the configuration shown in Figure 2, the amount of expensive palladium catalyst used can be reduced, thereby reducing costs. In order to reduce the amount of Pd-loaded anion exchange resin used, it is possible to fill the cathode chamber 25 with a mixture (mixed bed) of Pd-loaded anion exchange resin with other anion exchange resins or cation exchange resins, but in order to improve the efficiency of hydrogen utilization, it is preferable that at least a portion of the cathode chamber 25 is filled with Pd-loaded anion exchange resin in a single bed form. In other words, when filling the cathode chamber 25 with Pd-loaded anion exchange resin, it is preferable to fill it in a single bed form or a multiple bed form.

The water treatment device shown in Figures 1 and 2 is a general EDI device without the desalination chamber, but the water treatment device based on the present invention has the same configuration as a general EDI device by providing a desalination chamber, and it is possible to perform desalination processing in the desalination chamber and removal processing of dissolved oxygen in the cathode chamber. Figure 3 shows a water treatment device based on the present invention configured as an EDI device. The water treatment device shown in Figure 3 is the water treatment device shown in Figure 1, in which a concentration chamber 22 and a desalination chamber 23 are provided in this order from the anode chamber 21 side between the anode chamber 21 and the concentration chamber 24. The anode chamber 21 and the concentration chamber 22 are separated by a cation exchange membrane 31, the concentration chamber 22 and the desalination chamber 23 are separated by an anion exchange membrane 32, and the desalination chamber 23 and the concentration chamber 24 are separated by a cation exchange membrane 33. The concentration chamber 22 is filled with anion exchange resin (AER), and the deionization chamber 23 is filled with a mixed bed (MB) of cation exchange resin and anion exchange resin. The deionization chamber 23 is supplied with water to be treated that is separate from the water to be treated from which dissolved oxygen is to be removed. Feed water is supplied to the anode chamber 21 and the concentration chambers 22 and 24, and electrode water is discharged from the anode chamber 21, and concentrated water is discharged from the concentration chambers 22 and 24.

In the water treatment device shown in FIG. 3, by applying a direct current between the anode 11 and the cathode 12, the desalting process is performed on the water to be treated in the desalting chamber 23, similar to the desalting chamber in a typical EDI device, and the desalted water is discharged from the desalting chamber 23. Meanwhile, in the cathode chamber 25, a process is performed to remove dissolved oxygen contained in the water to be treated, similar to the case of the water treatment device shown in FIG. 1, and the treated water from which the dissolved oxygen has been removed is discharged from the cathode chamber 25. At this time, as described above, the hydrogen peroxide contained in the water to be treated is also removed.

Figure 4 shows another example of a water treatment device configured as an EDI device. The water treatment device shown in Figure 4 is designed to supply treated water discharged from the cathode chamber 25 of the water treatment device shown in Figure 3 directly to the desalting chamber 23. Therefore, with the water treatment device shown in Figure 4, desalted water from which dissolved oxygen has been removed and hydrogen peroxide has also been removed can be obtained.

In general, in an EDI device, multiple desalting compartments can be arranged between the anode and the cathode. In the water treatment device shown in Figures 3 and 4, which is configured as an EDI device, a repeating unit consisting of an anion exchange membrane 32, a desalting compartment 23, a cation exchange membrane 33, and a concentration compartment 24 is arranged between the anion exchange membrane 34 that divides the concentration compartment 22 adjacent to the anode chamber 21 and the cathode chamber 25, and multiple desalting compartments 23 can be arranged between the anode 11 and the cathode 12. The water treatment device shown in Figure 5 is the water treatment device shown in Figure 4, in which multiple desalting compartments 23 are arranged, and the treated water discharged from the cathode chamber 25 is distributed in parallel to the multiple desalting compartments 23 and passed through them. Desalted water from which dissolved oxygen has been removed and which has been desalted is discharged from each desalting compartment 23.

The water treatment device according to the present invention has been described above, but this water treatment device can be incorporated into a water treatment system that produces pure water or ultrapure water. The water treatment system that produces pure water or ultrapure water is composed of, for example, an activated carbon device (AC), a reverse osmosis membrane device (RO), an ultraviolet irradiation device (UV), an ion exchange resin device (IER), a membrane degassing device (MD), an EDI device, a non-regenerative ion exchange device (CP), various filters, etc. The water treatment device according to the present invention can remove dissolved oxygen, remove hydrogen peroxide, and perform desalination treatment, so it can be used to replace one or more of the membrane degassing device, the ion exchange resin device, the EDI device, and the non-regenerative ion exchange device, or can be installed in the front or rear of the membrane degassing device, the ion exchange resin device, the EDI device, and the non-regenerative ion exchange device to improve the performance of removing impurity components. Figure 6 shows an example of a water treatment system incorporating a water treatment device according to the present invention.

The water treatment system shown in FIG. 6 is a system for producing ultrapure water from raw water such as city water, and is composed of a primary pure water system for producing primary pure water from raw water, and a subsystem for producing ultrapure water from primary pure water. In the figure, the reference numeral 100 denotes any of the water treatment devices described with reference to FIGS. 1 to 5. In the primary pure water system, a raw water tank 41, a first reverse osmosis membrane device 51, a second reverse osmosis membrane device 52, a reverse osmosis membrane treated water tank 42, an ultraviolet irradiation device (UV) 55, and a water treatment device 100 are arranged in this order, and the raw water is treated in this order, resulting in the production of primary pure water. If the water treatment device 100 based on the present invention is not used, an ion exchange resin device, an EDI device, a non-regenerative ion exchange device, and a membrane degassing device will be provided instead of the water treatment device 100. In the primary pure water system, when the downstream equipment to which the pure water is supplied becomes full, the produced primary pure water is circulated to the reverse osmosis membrane treated water tank 42.

In the subsystem, a pure water tank 45 is provided to store the primary pure water from the primary pure water system, and an ultraviolet ray irradiation device (UV) 61, a non-regenerative ion exchange device (CP) 63, a membrane degassing device (MD) 65, and an ultrafiltration membrane (UF) 67 are arranged in this order at the outlet of the pure water tank 45, and the primary pure water is treated in this order to produce ultrapure water. A part of the produced ultrapure water is circulated to the pure water tank 45. A microfiltration membrane may be used instead of the ultrafiltration membrane (UF) 67. In addition, in the subsystem, instead of the non-regenerative ion exchange device 63 and the membrane degassing device 65, a water treatment device based on the present invention may be provided, or may be provided before or after the non-regenerative ion exchange device 63 and the membrane degassing device 65. When a membrane degasser is installed in both the primary pure water system and the subsystem, the overall dissolved oxygen removal rate may be increased by installing multiple membrane degassers in series. When installing multiple membrane degassers in series in this way, some of the membrane degassers can be replaced with water treatment equipment based on the present invention.

7 shows another example of a water treatment system incorporating a water treatment device according to the present invention. In the water treatment system shown in FIG. 7, the water treatment device 100 is positioned in front of the ultraviolet irradiation device 55 of the primary pure water system in the water treatment system shown in FIG. 6, and a treatment device (IER/EDI) 56, which is an ion exchange resin device or an EDI device, is arranged in the rear of the ultraviolet irradiation device 55. The water in the reverse osmosis membrane treated water tank 42 passes through the water treatment device 100 based on the present invention, the ultraviolet irradiation device 55, and the treatment device 56 in that order, and primary pure water is discharged from the treatment device 56, which is an ion exchange resin device or an EDI device. When the ultraviolet irradiation device 55 irradiates ultraviolet rays to the water to be treated to decompose and remove total organic carbon (TOC) components, it is known that the removal rate of TOC decreases when the dissolved oxygen concentration in the water to be treated is high. Therefore, in the water treatment system shown in FIG. 6, the dissolved oxygen concentration in the inlet water of the ultraviolet irradiation device 55 can be lowered, and the TOC removal rate in the ultraviolet irradiation device can be increased when the dissolved oxygen concentration in the raw water is high.

Figure 8 shows yet another example of a water treatment system incorporating a water treatment device according to the present invention. The water treatment system shown in Figure 8 is the water treatment system shown in Figure 6, in which a water treatment device 100 based on the present invention is also placed between the outlet of the ultraviolet irradiation device 61 and the inlet of the non-regenerative ion exchange device 63 of the subsystem. When organic matter in water is decomposed and removed by ultraviolet irradiation, carbonate ions and bicarbonate ions are generated, but the water treatment device 100 can also remove carbonate ions and bicarbonate ions. Therefore, by placing the water treatment device 100 in the subsystem as shown in Figure 8, the processing load on the subsequent non-regenerative ion exchange device 63 can be reduced and the impurity removal performance can be improved.

Next, the present invention will be explained in more detail using examples.

[Example 1]
The water treatment device shown in FIG. 1 was assembled. The dimensions of the anode chamber 21, the concentration chamber 24, and the cathode chamber 25 were all 105 mm×105 mm×9.5 mm. Water with a dissolved oxygen concentration of 8.2 mg/L was prepared, and this water was passed through the cathode chamber 25 at 50 L/h as the water to be treated, and through the concentration chamber 24 at 5 L/h as the feed water. The water treatment device was operated by changing the value of the current flowing between the anode 11 and the cathode 12 in the range of 0.5 A to 2.5 A, and the dissolved oxygen concentration of the treated water discharged from the cathode chamber 25 was measured to obtain the dissolved oxygen removal rate. The results are shown in FIG. 9. From FIG. 9, it was found that there was a correlation between the current value and the dissolved oxygen removal rate, and that the dissolved oxygen removal rate could be improved by increasing the current density. This means that the dissolved oxygen could be removed by effectively utilizing the hydrogen generated in the cathode chamber 25.

[Example 2]
The same experiment as in Example 1 was carried out using the same apparatus as in Example 1, except that hydrogen peroxide was added to the water to be treated and the current setting during operation was 1.5 A. The hydrogen peroxide concentration in the treated water was measured and the removal rate of hydrogen peroxide was calculated. The results are shown in Table 1.

The results in Table 2 show that hydrogen peroxide can also be removed when the cathode chamber 25 is filled with Pd-loaded anion exchange resin. The dissolved oxygen removal rate was measured to be about 27%, which was similar to the dissolved oxygen removal rate in Example 1.

11 Anode 12 Cathode 21 Anode chamber 22, 24 Concentration chamber 23 Deionization chamber 25 Cathode chamber 31, 33 Cation exchange membrane 32, 34 Anion exchange membrane 100 Water treatment device

Claims (6)

A water treatment method for removing at least dissolved oxygen and hydrogen peroxide contained in water to be treated, comprising the steps of:
applying a direct current between an anode provided in the anode chamber and a cathode provided in a cathode chamber filled with an ion exchanger;
a step of passing the water to be treated through the cathode chamber to obtain treated water from the cathode chamber from which dissolved oxygen and hydrogen peroxide have been removed ;
having
the cathode chamber is partitioned by an ion exchange membrane on the anode chamber side, the anode chamber is partitioned by an ion exchange membrane on the cathode chamber side, and at least one of a concentration chamber and a deionization chamber is disposed between the anode chamber and the cathode chamber;
A water treatment method, wherein at least a part of the ion exchanger packed in the cathode chamber is an ion exchanger carrying a platinum group metal catalyst. 2. The water treatment method according to claim 1 , wherein the ion exchange membrane that partitions the cathode chamber is an anion exchange membrane, and the ion exchanger filled in the cathode chamber is an anion exchanger. 3. The water treatment method according to claim 1, further comprising a step of passing the treated water discharged from the cathode chamber through the desalting chamber, the desalting chamber being partitioned by an ion exchange membrane and filled with an ion exchanger, between the anode chamber and the cathode chamber, to desalt the treated water. an anode chamber including an anode;
a cathode chamber which is provided with a cathode, is filled with an ion exchanger, and is supplied with the water to be treated;
having
the cathode chamber is partitioned by an ion exchange membrane on the anode chamber side, the anode chamber is partitioned by an ion exchange membrane on the cathode chamber side, and at least one of a concentration chamber and a deionization chamber is disposed between the anode chamber and the cathode chamber;
At least a part of the ion exchanger packed in the cathode chamber is an ion exchanger carrying a platinum group metal catalyst,
A water treatment device in which a direct current is applied between the anode and the cathode, and treated water from which dissolved oxygen and hydrogen peroxide have been removed and which is obtained from the cathode chamber . 5. The water treatment device according to claim 4 , wherein the ion exchange membrane that partitions the cathode chamber is an anion exchange membrane, and the ion exchanger filled in the cathode chamber is an anion exchanger. the deionization chamber, which is partitioned by an ion exchange membrane and filled with an ion exchanger, is provided between the anode chamber and the cathode chamber ;
The concentration chamber is provided between the anode chamber and the cathode chamber,
The water treatment device according to claim 4 or 5 , wherein the treated water discharged from the cathode chamber is supplied to the deionization chamber.

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