KR102075598B1 - Water treatment device and water treatment method - Google Patents

Abstract

Provided are a water treatment apparatus and a water treatment method capable of reducing the concentration of boron in treated water. The plurality of electric deionized water production apparatuses are provided with a desalination chamber filled with an ion exchanger, partitioned by an anion exchange membrane located on the anode side and a cation exchange membrane located on the cathode side, between the anode and the cathode, to prepare a plurality of electric deionized water. Each desalination chamber of the apparatus is connected in series, and the plurality of desalination chambers connected in series pass through the water to be treated to allow the treated water to flow out, and the uppermost portion of the first stage desalination chamber through which the water to be treated passes first, and the treatment. Anion exchanger is filled in the lowest part of the desalination chamber of the last stage which outflows water, and it is located between the uppermost part of the desalination chamber of 1st stage and the most downstream part of the desalination chamber of a final stage as a part of some desalination chamber. At least part is filled with a cation exchanger.

Description

Water treatment device and water treatment method

The present invention relates to a water treatment apparatus and a water treatment method, and more particularly, to a water treatment apparatus and a water treatment method using an electric deionized water production apparatus.

BACKGROUND ART A deionized water production apparatus 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. In such an apparatus, when the ion exchanger of the ion exchanger is saturated and the desalination performance is lowered, it is necessary to perform a treatment (regeneration treatment) for regenerating the ion exchanger with a drug such as an acid or an alkali. The regeneration treatment is a treatment in which a cation or anion adsorbed on an ion exchanger is replaced with hydrogen ions (H +) and hydroxide ions (OH-) derived from an acid or an alkali, thereby revitalizing the desalting performance of the ion exchanger. to be. The deionized water production apparatus which requires a regeneration treatment with a chemical agent has a problem that it is not possible to perform continuous operation, and the labor of refilling the chemical for regeneration treatment is also required.

In order to solve these problems, electric deionized water production apparatus (also called EDI (Electro DeIonization) apparatus) which does not need regeneration by a chemical | medical agent has been developed and put into practical use in recent years.

An EDI apparatus is a combination of electrophoresis and electrodialysis. The EDI apparatus includes a desalting chamber filled with an ion exchanger (anion exchanger and / or cation exchanger) between an anion exchange membrane that transmits only anions and a cation exchange membrane that transmits only cations. In the EDI apparatus, the concentration chamber is disposed outside each of the anion exchange membrane and the cation exchange membrane from the desalination chamber. And a desalination chamber and each concentration chamber are arrange | positioned between the anode chamber provided with an anode, and the cathode chamber provided with a cathode. In the desalting chamber, an anion exchange membrane is arranged on the side near the anode, and a cation exchange membrane is disposed on the side near the cathode. The enrichment chamber adjacent through the desalting chamber and the anion exchange membrane is adjacent to the anode chamber via the cation exchange membrane. The enrichment chamber adjacent via the desalting chamber and the cation exchange membrane is adjacent to the cathode chamber via the anion exchange membrane.

In order to produce deionized water (treated water) from the water to be treated by the EDI apparatus, the water to be treated is passed through the desalination chamber while a direct current voltage is applied between the anode and the cathode. Then, the ionic component in the water to be treated is adsorbed to the ion exchanger in the desalting chamber, deionization (desalting) treatment is performed, and deionized water flows out of the desalting chamber. At this time, in the desalting chamber, depending on the applied voltage, an interface between heterogeneous ion exchange materials, for example, an interface between an anion exchanger and a cation exchanger, an interface between an anion exchanger and a cation exchange membrane, or an anion exchange membrane and a cation exchanger At the interface, as shown in the following equation, the dissociation reaction of water occurs, producing hydrogen ions and hydroxide ions.

^{_{H 2 O → H + + OH}} -

By this hydrogen ion and hydroxide ion, the ion component adsorbed to the ion exchanger in a desalting chamber is ion-exchanged and is liberated from an ion exchanger. Among the advantageous ionic components, the anions are electrophoresed to the anion exchange membrane and electrodialyzed by the anion exchange membrane, and are discharged into the concentrated water flowing from the desalination chamber through the concentration chamber on the anode side. Similarly, cations in the advantageous ionic components are electrophoresed to the cation exchange membrane and electrodialyzed by the cation exchange membrane, and discharged into the concentrated water flowing through the concentration chamber on the cathode side from the desalination chamber. As a result, the ionic component in the water to be treated 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 the application of a direct current voltage continuously act as regenerants of acids and alkalis for regenerating ion exchangers. For this reason, in the EDI apparatus, the regeneration process by the chemical | medical agent supplied from the outside becomes fundamentally unnecessary, and continuous operation can be performed without regenerating the ion exchanger by a chemical | medical agent.

Japanese Patent Laid-Open No. 2001-191080 discloses an electric deionization device in which each desalting chamber of two EDI devices is connected in series. In the electric deionization apparatus described in this patent document, the anion exchanger alone or a mixture of anion exchanger and cation exchanger is filled in the desalting chamber of the first stage, and the anion exchanger and the cation exchange of the desorption chamber of the second stage. The mixture of sieves is filled.

At present, there is a demand for low concentration of boron in treated water (deionized water), and a water treatment technology capable of meeting this demand is desired.

An object of the present invention is to provide a water treatment apparatus and a water treatment method capable of reducing the concentration of boron in treated water.

The water treatment device according to the present invention is a water treatment device having a plurality of electric deionized water production devices, wherein each of the plurality of electric deionized water production devices includes an anion exchange membrane located on the anode side between the positive electrode and the negative electrode; A desalting chamber which is partitioned by a cation exchange membrane located on the cathode side and filled with an ion exchanger, and each of said desalting chambers of said plurality of electric deionized water production apparatuses is in series communication with each other; In fact, an anion is supplied to the uppermost part of the desalination chamber at the first stage through which the treated water is passed through, and the treated water is first passed through at the end of the desalting chamber at the final stage through which the treated water is discharged. The exchanger is filled alone, and as a part of the plurality of desalting chambers, the most upstream portion of the desalting chamber of the first stage and the desalting chamber of the final stage The portion between ryubu, is charged at least a cation exchange body.

The water treatment method according to the present invention comprises a plurality of electric deionized water production apparatuses having a desalting chamber filled with an ion exchanger between an anode and a cathode, the anion exchange membrane located on the anode side and the cation exchange membrane located on the cathode side. And each of the desalination chambers of the plurality of electric deionized water production apparatuses is connected in series, and the plurality of desalination chambers connected in series passes through the water to be treated and outflows the treated water. The anion exchanger is filled in the uppermost part of the desalination chamber of the first stage and the lowest downstream of the desalting chamber of the final stage through which the treated water flows out first, and the first stage is a part of the plurality of desalination chambers. The water treatment apparatus in which at least the cation exchanger is filled in the portion between the most upstream part of the desalination chamber and the most downstream part of the desalting chamber of the final stage. In the water treatment method used, the treated water is passed through a plurality of desalination chambers connected in series while applying a DC voltage between the anode and the cathode to treat the treated water and to flow out the treated water.

According to the present invention, each of the desalination chambers of the plurality of electric deionized water production apparatuses is connected in series, and among the plurality of desalination chambers connected in series, the most upstream portion of the desalination chamber at the first stage and the most downstream portion of the desalination chamber at the final stage Is filled with an anion exchanger alone, and a portion therebetween is filled with at least a cation exchanger. For this reason, as will be apparent from the examples described later, the water treatment apparatus in which a mixture of an anion exchanger and a cation exchanger is filled in the desalination chamber of the first stage, or an anion exchanger Compared to the water treatment apparatus filled with the mixture of the cation exchanger, it is possible to reduce the concentration of boron in the treated water.

1 is a diagram illustrating an EDI apparatus 101 of the first aspect.
2 shows an EDI apparatus 102 of the second aspect.
3 shows an EDI apparatus 103 of the third aspect.
4 shows an EDI device 104 of a fourth aspect.
5 shows an EDI device 105 of a fifth aspect.
6 shows an EDI device 106 of the sixth aspect.
7 is a diagram illustrating the water treatment device 201 of the first embodiment of the present invention.
8 is a diagram showing the water treatment device 202 of the second embodiment of the present invention.
9 is a diagram showing the water treatment device 203 of the third embodiment of the present invention.
10 is a diagram showing the water treatment device 204 of the fourth embodiment of the present invention.
11 is a view showing the water treatment device 205 of the fifth embodiment of the present invention.
12 is a diagram showing the water treatment device 206 of the sixth embodiment of the present invention.
It is a figure which shows the water treatment apparatus 207 of 7th Embodiment of this invention.
14 is a diagram showing the water treatment device 208 of the eighth embodiment of the present invention.
15 is a diagram illustrating an EDI device 301.
16 is a view showing a water treatment apparatus of Comparative Example 1. FIG.
17 is a view showing a water treatment apparatus of Comparative Example 2. FIG.
18 is a view showing a water treatment apparatus of Comparative Example 3. FIG.
19 is a view showing a water treatment apparatus of Comparative Example 4. FIG.
It is a figure which shows the measurement result of the boron concentration of the treated water in Examples 1-8 and Comparative Examples 1-4.
FIG. 21 is a diagram showing a measurement result of boron concentration of treated water in Examples 9 to 10. FIG.
FIG. 22 is a graph showing measurement results of boron concentration in treated water in Examples 11 to 13. FIG.
FIG. 23 is a view showing a measurement result of boron concentration of treated water in Example 14; FIG.
[Description of the code]
11: anode
12: cathode
21: anode chamber
22, 24: concentration chamber
23a, 23b, 23c, 23d, 23e, 23f: desalination chamber
23d-1, 23e-1, 23f-1: first desalination chamber
23d-2, 23e-2, 23f-2: second desalination chamber
25: cathode chamber
31, 33: cation exchange membrane
32, 34: anion exchange membrane
36: intermediate ion exchange membrane
CER, K: cation exchanger
AER, A: Anion Exchanger
101 to 106: EDI device
201 to 208: water treatment apparatus

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to drawings. The water treatment apparatus of embodiment of this invention is equipped with several EDI apparatus (electric deionized water manufacturing apparatus). In the EDI apparatus, an ion exchanger is filled in the desalting chamber, and ions captured by the ion exchange reaction move to the ion exchange membrane via the ion exchanger. For this reason, ion can be removed efficiently. In the EDI apparatus, the current flows at a current density at which the decomposition reaction of water occurs. The minimum current at which the decomposition reaction of water occurs is called the limit current. In an EDI device, a current above the limit current flows. Therefore, even when the ion concentration in the water to be treated is low, the hydrogen ions and the hydroxide ions generated by the decomposition reaction of water migrate through the ion exchanger to the ion exchange membrane, and are responsible for the transfer of charges. In this way, in the EDI apparatus, since electricity flows in the pure water, the pure water can be produced. On the other hand, in the electrodialysis apparatus ED, since the ion exchanger is not filled in the desalination chamber and a current smaller than the limit current flows, the decomposition reaction of water cannot be used.

First, six types of EDI apparatuses 101 to 106 used in the embodiment of the present invention will be described. These six types of EDI devices differ from each other in the desalination chamber.

<EDI Device 101>

1 is a diagram illustrating an EDI apparatus 101.

In the EDI apparatus 101, the concentration chamber 22 is sequentially disposed from the anode chamber 21 side between the anode chamber 21 having the anode 11 and the cathode chamber 25 having the cathode 12. The desalination chamber 23a and the concentration chamber 24 are provided.

The anode chamber 21 and the concentration chamber 22 are adjacent with the cation exchange membrane 31 interposed therebetween, and the concentration chamber 22 and the desalination chamber 23a are adjacent with the anion exchange membrane 32 interposed therebetween. 23a and the concentration chamber 24 are adjacent with the cation exchange membrane 33 interposed, and the concentration chamber 24 and the cathode chamber 25 are adjacent with the anion exchange membrane 34 interposed therebetween. The enrichment chamber 24 is an example of a 1st enrichment chamber, and the enrichment chamber 22 is an example of a 2nd enrichment chamber.

The desalting chamber 23a is partitioned by the anion exchange membrane 32 and the cation exchange membrane 33. In the desalting chamber 23a, an anion exchanger (AER) is filled in the form of a single phase. As an anion exchanger (AER), an anion exchange resin is used, for example. The water to be treated is passed through the desalination chamber 23a.

Supply water passes through the concentration chambers 22 and 24, the anode chamber 21, and the cathode chamber 25, respectively. Pure water, untreated water, etc. are used as supply water.

The water flow direction of the supply water to the concentration chambers 22 and 24 has a relationship with the water flow direction of the water to be treated to the desalination chamber 23a and countercurrent. The water flow direction of the supply water to the anode chamber 21 and the cathode chamber 25 has a relationship with the water flow direction of the water to be treated to the desalination chamber 23a and countercurrent. Moreover, the relationship of these water flow directions can be changed suitably. In addition, the number of electrodes discharged from the cathode chamber 25 is caused to flow in the anode chamber 21 as supply water. The number of electrodes discharged from the anode chamber 21 may flow in the cathode chamber 25 as supply water.

<EDI Device 102>

2 shows an EDI device 102. The EDI apparatus 102 differs from the ion exchanger charged in the desalination chamber compared with the EDI apparatus 101 shown in FIG. In the desalting chamber 23b of the EDI apparatus 102, the anion exchanger AER is filled alone in the region on the inlet side 23b1 of the water to be treated, and the cation exchanger CER in the region on the outlet side 23b2. ) Is charged alone. As the cation exchanger (CER), for example, a cation exchange resin is used.

<EDI device 103>

3 is a diagram illustrating the EDI apparatus 103. In the EDI apparatus 103, compared with the EDI apparatus 102 shown in FIG. 2, the position of the anion exchanger (AER) and cation exchanger (CER) which are filled in the desalting chamber is reversed. In other words, in the desalting chamber 23c of the EDI apparatus 103, the cation exchanger CER is filled alone in the region on the inlet side 23c1 of the water to be treated, and the anion exchanger in the region on the outlet side 23c2. (AER) is charged alone.

<EDI Device 104>

4 shows an EDI device 104. In the desalting chamber 23d of the EDI apparatus 104, the intermediate ion exchange membrane 36 is provided between the anion exchange membrane 32 and the cation exchange membrane 33, and the desalting chamber 23d is formed by the intermediate ion exchange membrane 36. It is divided into the desalination chamber 23d-1 and the desalination chamber 23d-2. As the intermediate ion exchange membrane 36, any of a composite membrane such as an anion exchange membrane, a cation exchange membrane, and a bipolar membrane can be used. In the EDI apparatus 104, an anion exchange membrane is used as the intermediate ion exchange membrane 36. The desalination chamber 23d-1 on the anode side is an example of the first desalination chamber, and the desalination chamber 23d-2 on the cathode side is an example of the second desalination chamber.

The anion exchanger (AER) is filled in a single phase form in the desalination chamber 23d-1, and a cation exchanger (CER) is filled in a single phase in the desalination chamber 23d-2. The water to be treated passes through the desalination chamber 23d-1 so that water flowing out of the desalination chamber 23d-1 flows into the desalination chamber 23d-2 (arrow 104a, arrow 104b) (104c)), the desalination chamber 23d-1 and the desalination chamber 23d-2 are connected in series.

The water flow direction of the supply water to the concentration chambers 22 and 24 has a relationship between the water flow direction of the water to be treated to the desalination chambers 23d-1 and 23d-2 and countercurrent. The water flow direction of the supply water to the anode chamber 21 and the cathode chamber 25 has a relationship with the water flow direction of the water to be treated to the desalination chambers 23d-1 and 23d-2 and countercurrent. Moreover, the relationship of these water flow directions can be changed suitably. The number of electrodes discharged from the cathode chamber 25 flows to the anode chamber 21 as supply water. The number of electrodes discharged from the anode chamber 21 may flow in the cathode chamber 25 as supply water.

<EDI Device 105>

5 shows the EDI apparatus 105. Compared to the EDI apparatus 104 shown in FIG. 4, the EDI apparatus 105 has reversed the order of the number of water flow of the to-be-processed water in a 1st desorption chamber and a 2nd desorption chamber. In the EDI apparatus 105, the water to be treated is supplied to the desalination chamber 23e-2 so that water flowing out from the desalination chamber 23e-2 flows into the desalination chamber 23e-1 (arrow 105a). Arrow 105b, arrow 105c), the desalination chamber 23e-1 and the desalination chamber 23e-2 are connected in series.

The water flow direction of the supply water to the concentration chambers 22 and 24 has a relationship between the water flow direction of the water to be treated to the desalination chambers 23e-1 and 23e-2 and countercurrent. The water flow direction of the supply water to the anode chamber 21 and the cathode chamber 25 has a relationship with the water flow direction of the water to be treated to the desalination chambers 23e-1 and 23e-2 and countercurrent. Moreover, the relationship of these water flow directions can be changed suitably. The number of electrodes discharged from the cathode chamber 25 flows to the anode chamber 21 as supply water. The number of electrodes discharged from the anode chamber 21 may flow in the cathode chamber 25 as supply water.

<EDI Device 106>

6 shows an EDI device 106. The EDI device 106 differs from the EDI device 104 shown in FIG. 4 in the ion exchanger filled in the desalination chamber on the cathode side. In the desalination chamber 23f-2, the cation exchanger CER is filled alone in the region of the inlet side 23f-21 of the water flowing out of the desalting chamber 23f-1, and the outlet side 23f-22. The anion exchanger (AER) is filled alone in the region of). In the EDI apparatus 106, the water to be treated is supplied to the desalination chamber 23f-1 so that water flowing out from the desalination chamber 23f-1 flows into the desalination chamber 23f-2 (arrows 106a, Arrow 106b, arrow 106c), the desalination chamber 23f-1, and the desalination chamber 23f-2 are connected in series.The desalination chamber 23f-1 and the desalination chamber 23f. The flow direction of the water to be treated in -2) is in the countercurrent direction, and an anion exchange membrane is used as the intermediate ion exchange membrane 36.

The water flow direction of the supply water to the concentration chambers 22 and 24 has a relationship between the water flow direction of the water to be treated and the countercurrent flow to the desalination chamber 23f-2. The water flow direction of the supply water to the anode chamber 21 and the cathode chamber 25 has a relationship with the water flow direction of the to-be-processed water to the desalination chamber 23f-2. Moreover, the relationship of these water flow directions can be changed suitably. The number of electrodes discharged from the cathode chamber 25 flows to the anode chamber 21 as supply water. The number of electrodes discharged from the anode chamber 21 may flow in the cathode chamber 25 as supply water.

First Embodiment

7 is a diagram illustrating the water treatment device 201 of the first embodiment of the present invention. The water treatment device 201 has an EDI device 102 and an EDI device 103. The desalting chamber 23b of the EDI apparatus 102 and the desalting chamber 23c of the EDI apparatus 103 are connected in series in this order. Water flowing out from the outlet side 23b2 of the desalination chamber 23b flows into the desalination chamber 23c from the inlet side 23c1. Between the EDI apparatus 102 and the EDI apparatus 103, the enrichment chamber is not connected in series and supply water (pure water) is supplied separately. Supply water (pure water) is separately supplied to the electrode chamber (cathode chamber and anode chamber) of the EDI apparatus 102 and the electrode chamber (cathode chamber and anode chamber) of the EDI apparatus 103 separately. In addition, the concentration chamber may be connected in series between the EDI apparatus 102 and the EDI apparatus 103. In addition, a common supply water may be supplied to the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 102 and the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 103.

Moreover, in the water treatment apparatus of this embodiment and each embodiment described below, the upstream side in the direction in which the to-be-processed water of the EDI apparatus of a front flows, ie, the desalination chamber of the 1st stage through which to-be-processed water passes for the first time, It is preferable that the reverse osmosis membrane device 111 is provided on the upstream side in the direction in which the water to be treated flows. The reverse osmosis membrane device 111 can lower the silica concentration of the water to be treated, for example, 100 μg SiO ₂ / L or less, and the boron concentration of the water to be treated, for example, 100 μg B / L or less. . Although not shown, two reverse osmosis membrane devices 111 are more preferably provided in series. Further, the decarbonation film device 112 is located upstream in the direction in which the water to be processed in the EDI apparatus in the front flows, that is, in the upstream side in the direction in which the water to be treated flows in the first stage desalination chamber through which the water is first passed. Is preferably installed. The decarbonation membrane device 112 may lower the carbonic acid concentration of the water to be treated, for example, 5 mg CO ₂ / L or less. The reverse osmosis membrane apparatus 111 and the decarboxylation membrane apparatus 112 may be either upstream in the direction in which the water to be treated flows.

Next, the water treatment performed in the desalination chambers 23b and 23c of the water treatment apparatus 201 will be described.

In the EDI apparatuses 102 and 103, water is supplied to 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. In one state, the water to be treated is passed from the inlet side 23b1 of the desalination chamber 23b of the EDI apparatus 102.

In the EDI apparatus 102, it is estimated that the following processing is performed with respect to the to-be-processed water.

Boron in the water to be treated is dissociated as an anion and adsorbed to the anion exchanger AER when it comes into contact with the anion exchanger AER filled in the region on the inlet side 23b1 of the desalting chamber 23b. In addition, a part of boron in the water to be treated remains in the water to be treated without being adsorbed by the anion exchanger (AER). The to-be-processed water in which boron remained flows in the part (region) in which the cation exchanger (CER) was filled in the desalination chamber 23b.

At this time, in the desalting chamber 23b, the dissociation reaction of water occurs due to the applied voltage between the anode 11 and the cathode 12 to generate hydrogen ions and hydroxide ions. Then, the anion (boron) adsorbed to the anion exchanger (AER) in the desalting chamber 23b is ion-exchanged by this hydroxide ion, and is liberated from the anion exchanger (AER). The released anions move to the concentration chamber 22 via the anion exchange membrane 32 and are discharged from the concentration chamber 22 as concentrated water.

When the water to be processed that has passed through the portion filled with the anion exchanger (AER) in the desalting chamber (23b) enters the portion filled with the cation exchanger (CER) in the desalting chamber (23b), the cation included in the water to be treated. It is adsorbed by this cation exchanger (CER). The cations adsorbed on the cation exchanger (CER) are ion-exchanged and released from the cation exchanger (CER) by the hydrogen ions generated by the dissociation reaction of water. The free cations move to the concentration chamber 24 via the cation exchange membrane 33 and are discharged from the concentration chamber 24 as concentrated water.

The hydroxide ions in the water to be treated move to the concentration chamber 22 via the anion exchange membrane 32 and are discharged from the concentration chamber 22 as concentrated water.

In addition, the hydroxide ions in the water to be treated react with the hydrogen ions generated by ion dissociation and water dissociation from the cation exchanger (CER) to form water (H ₂ O). For this reason, the concentration of hydroxide ion in the to-be-processed water which flows out from the desalination chamber 23b becomes lower than when the cation exchanger CER does not exist in the desalination chamber 23b. Moreover, the hydroxide ion in the to-be-processed water may adsorb | suck to an anion exchanger (AER) instead of boron (anion). For this reason, when the density | concentration of hydroxide ion in to-be-processed water becomes high too much, the adsorption efficiency of boron (anion) by the anion exchanger (AER) of a later stage may fall. Accordingly, the hydroxide ions in the water to be treated react with the hydrogen ions adsorbed on the cation exchanger (CER) to become water (H ₂ O), thereby reducing the concentration of the hydroxide ions in the later-described anion exchanger (AER) in the EDI apparatus 103. Adsorption efficiency of boron (anion) is improved.

The to-be-processed water which flowed out from the desalination chamber 23b of the EDI apparatus 102 flows in into the desalination chamber 23c of the EDI apparatus 103 from the inlet side 23c1.

In the EDI apparatus 103, it is assumed that the following processing is performed.

When the water to be discharged from the desalting chamber 23b flows into the region filled with the cation exchanger CER of the desalting chamber 23c, the cation exchanger CER of the desalting chamber 23b is supplied to the treated water. The same processing as that performed in the filled region is performed. For this reason, the concentration of hydroxide ions in the water to be treated which flows out from the region filled with the cation exchanger CER of the desalting chamber 23c is such that when no cation exchanger CER is present in the desalting chamber 23c. Lower than

The water to be processed passing through the region filled with the cation exchanger CER of the desalting chamber 23c flows into the region filled with the anion exchanger AER of the desalting chamber 23c.

Boron in the water to be treated is dissociated as an anion and adsorbed to the anion exchanger (AER) when it comes into contact with the anion exchanger (AER) filled in the region of the outlet side 23c2 of the desalting chamber 23c. At this time, since the water to be treated has passed through the cation exchanger (CER), the concentration of hydroxide ions in the water to be treated is lower than before passing through the cation exchanger (CER). Therefore, the adsorption efficiency of boron (anion) by the anion exchanger (AER) filled in the region of the outlet side 23c2 of the desalting chamber 23c is improved. Therefore, the concentration of boron in the treated water flowing out of the desalting chamber 23c can be reduced.

In addition, by using a plurality of EDI devices, the concentration of boron in the treated water is reduced. For this reason, the following effects are exhibited compared with the case where the ion exchanger was charged in the order of "anion exchanger → cation exchanger → anion exchanger" in the desalination chamber of one EDI apparatus, for example.

(1) Drift of current in the EDI apparatus can be suppressed.

For example, when the ion exchangers are charged in the order of "anion exchanger → cation exchanger → anion exchanger" in the desalting chamber of one EDI apparatus, the electrical resistance between the anion exchanger and the cation exchanger is different. The current flows due to the difference in the electrical resistance.

On the other hand, in the case of using a plurality of EDI devices, compared with the case of using one EDI device, the type can be reduced by the ion exchanger charged in one desalting chamber, and the current according to the difference in the electrical resistance of the ion exchanger. The drift of can be reduced.

(2) Since the electrode plate can be divided, control of the current value becomes easy.

As the current density increases, the electrode plate tends to deteriorate. In addition, when the ion exchange membrane or the ion exchange resin constituting the EDI device is operated at a high current value with a low ion load, deterioration such as electrical burnout tends to occur. For example, it is considered that it is also possible to perform a more stable operation by lowering the current value of the EDI device in the subsequent stage where the ion load is reduced.

(3) It becomes possible to reduce the load on the EDI apparatus of the next stage.

Since the latter EDI apparatus processes the treated water processed by the EDI apparatus at the front end thereof, the processing load is lower than that of the treated water which has not been processed at all. Therefore, it is assumed that the rear end EDI apparatus has less progression of deterioration than the front end EDI apparatus and can be used for a longer period of time. It is considered that the rear end EDI device can be exchanged less frequently than the front end EDI device.

Second Embodiment

8 is a diagram showing the water treatment device 202 of the second embodiment of the present invention. The water treatment device 202 has an EDI device 101 and an EDI device 103. The desalting chamber 23a of the EDI apparatus 101 and the desalting chamber 23c of the EDI apparatus 103 are connected in series in this order. The water to be treated flows into the desalination chamber 23a. And the water which flowed out from the desalination chamber 23a flows into the desalination chamber 23c from the inlet side 23c1. Between the EDI apparatus 101 and the EDI apparatus 103, the enrichment chamber is not connected in series and supply water is supplied separately. Supply water is supplied separately to the electrode chamber (cathode chamber and anode chamber) of the EDI apparatus 101 and the electrode chamber (cathode chamber and anode chamber) of the EDI apparatus 103.

Next, the water treatment performed in the desalination chambers 23a and 23c of the water treatment apparatus 202 will be described.

In the EDI apparatuses 101 and 103, water is supplied to 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. In this state, the water to be treated is passed through the desalination chamber 23a of the EDI apparatus 101.

In the EDI apparatus 101, it is assumed that the same processing as that performed using the anion exchanger AER filled in the region on the inlet side 23b1 of the desalting chamber 23b in the first embodiment is performed. do. The to-be-processed water which flowed out from the desalination chamber 23a of the EDI apparatus 101 flows into the desalination chamber 23c of the EDI apparatus 103 from the inlet side 23c1. In the EDI apparatus 103, it is estimated that the same processing as that performed in the EDI apparatus 103 shown in the first embodiment is performed.

For this reason, similarly to the first embodiment, the adsorption efficiency of boron (anion) by the anion exchanger (AER) filled in the region of the outlet side 23c2 of the desalination chamber 23c is improved. Therefore, the concentration of boron in the treated water flowing out of the desalting chamber 23c can be reduced.

Third Embodiment

9 is a diagram showing the water treatment device 203 of the third embodiment of the present invention. The water treatment device 203 has an EDI device 102 and an EDI device 101. The desalting chamber 23b of the EDI apparatus 102 and the desalting chamber 23a of the EDI apparatus 101 are connected in series in this order. The water to be treated flows into the desalination chamber 23b from the inlet side 23b1. Water flowing out from the desalting chamber 23b flows into the desalting chamber 23a. Between the EDI apparatus 102 and the EDI apparatus 101, the enrichment chamber is not connected in series and supply water is supplied separately. Supply water is supplied separately to the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 102 and the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 101 separately.

Next, the water treatment performed in the desalination chambers 23b and 23a of the water treatment apparatus 203 will be described. In the EDI apparatuses 102 and 101, water is supplied to 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. In one state, the water to be treated is passed from the inlet side 23b1 of the desalination chamber 23b of the EDI apparatus 102. In the EDI apparatus 102, it is estimated that the same processing as that performed in the EDI apparatus 102 shown in the first embodiment is performed. The water to be discharged from the outlet side 23b2 of the desalting chamber 23b of the EDI apparatus 102 flows into the desalting chamber 23a of the EDI apparatus 101. In the EDI apparatus 101, it is estimated that the same processing as that performed using the anion exchanger AER filled in the region on the outlet side 23c2 of the desalting chamber 23c in the first embodiment is performed. do.

Therefore, similarly to the first embodiment, the adsorption efficiency of boron (anion) by the anion exchanger (AER) filled in the desalting chamber 23a is improved, and boron in the treated water flowing out of the desalting chamber 23a is improved. It is possible to achieve a low concentration.

Fourth Embodiment

10 is a diagram showing the water treatment device 204 of the fourth embodiment of the present invention.

The water treatment device 204 has an EDI device 104 and an EDI device 101. The desalting chamber 23d-1 of the EDI apparatus 104, the desalting chamber 23d-2 of the EDI apparatus 104, and the desalting chamber 23a of the EDI apparatus 101 are connected in series in this order. have. The water to be treated flows in from the desalination chamber 23d-1. Between the EDI apparatus 104 and the EDI apparatus 101, the enrichment chamber is not connected in series and supply water is supplied separately. Supply water is supplied separately to the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 104, and the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 101 separately.

Next, the water treatment performed in the desalination chambers 23d-1 and 23d-2 and the desalting chamber 23a of the water treatment apparatus 204 will be described.

In the EDI apparatuses 104 and 101, water is supplied to 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. In one state, the water to be treated is passed through the desalination chamber 23d-1 of the EDI apparatus 104.

In the desalination chamber 23d-1 of the EDI apparatus 104, the anion exchanger AER filled in the region of the inlet side 23b1 of the desalting chamber 23b in the first embodiment is performed. It is assumed that the same processing as the processing is performed. The to-be-processed water which flowed out from the desalination chamber 23d-1 flows into the desalination chamber 23d-2. In the desalination chamber 23d-2, the same treatment as that performed using the cation exchanger CER filled in the region on the outlet side 23b2 of the desalting chamber 23b in the first embodiment is performed. It is assumed to be done. The to-be-processed water which flowed out from the desalination chamber 23d-2 flows into the desalination chamber 23a of the EDI apparatus 101. FIG. In the EDI apparatus 101, it is estimated that the same processing as that performed using the anion exchanger AER filled in the region on the outlet side 23c2 of the desalting chamber 23c in the first embodiment is performed. do.

Therefore, similarly to the first embodiment, the adsorption efficiency of boron (anion) by the anion exchanger (AER) filled in the desalting chamber 23a is improved, and boron in the treated water flowing out of the desalting chamber 23a is improved. It is possible to achieve a low concentration.

Fifth Embodiment

11 is a view showing the water treatment device 205 of the fifth embodiment of the present invention.

The water treatment device 205 has an EDI device 101 and an EDI device 105. The desalination chamber 23a of the EDI apparatus 101, the desalination chamber 23e-2 of the EDI apparatus 105, and the desalination chamber 23e-1 of the EDI apparatus 105 are arranged in this order in series. In communication. The water to be treated flows in from the desalination chamber 23a. Between the EDI apparatus 101 and the EDI apparatus 105, the enrichment chamber is not connected in series and supply water is supplied separately. Supply water is supplied separately to the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 101 and the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 105 separately.

Next, the water treatment performed in the desalination chamber 23a and the desalination chambers 23e-2 and 23e-1 of the water treatment apparatus 205 will be described.

In the EDI apparatuses 101 and 105, water is supplied to 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. In this state, the water to be treated is passed through the desalination chamber 23a of the EDI apparatus 101.

In the desalting chamber 23a of the EDI apparatus 101, it is similar to the process performed using the anion exchanger AER filled in the area | region of the inlet side 23b1 of the desalting chamber 23b in 1st Embodiment. It is assumed that the processing of is performed. The water to be discharged from the desalination chamber 23a flows into the desalination chamber 23e-2 of the EDI apparatus 105.

In the desalination chamber 23e-2, the same treatment as that performed using the cation exchanger CER filled in the region on the inlet side 23c1 of the desalting chamber 23c in the first embodiment is performed. It is assumed to be done. The to-be-processed water which flowed out from the desalination chamber 23e-2 flows into the desalination chamber 23e-1. In the desalination chamber 23e-1, the same treatment as that performed using the anion exchanger AER filled in the region on the outlet side 23c2 of the desalting chamber 23c in the first embodiment is performed. It is assumed to be done.

Therefore, similarly to the first embodiment, the adsorption efficiency of boron (anion) by the anion exchanger (AER) filled in the desalination chamber 23e-1 is improved. Therefore, the concentration of boron in the treated water flowing out of the desalination chamber 23e-1 can be reduced.

Sixth Embodiment

12 is a diagram showing the water treatment device 206 of the sixth embodiment of the present invention.

The water treatment device 206 has an EDI device 106 and an EDI device 101. The desalination chamber 23f-1 of the EDI apparatus 106, the desalination chamber 23f-2 of the EDI apparatus 106, and the desalination chamber 23a of the EDI apparatus 101 communicate in series in this order. It is. The water to be treated flows in from the desalination chamber 23f-1. Between the EDI apparatus 106 and the EDI apparatus 101, the enrichment chamber is not connected in series and supply water is supplied separately. Supply water is supplied separately to the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 106 and the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 101 separately.

Next, the water treatment performed in the desalination chambers 23f-1 and 23f-2 and the desalting chamber 23a of the water treatment apparatus 206 will be described.

In the EDI devices 106 and 101, water is supplied to 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. In one state, the water to be treated is passed through the desalination chamber 23f-1 of the EDI apparatus 106.

In the desalination chamber 23f-1 of the EDI apparatus 106, it is performed using an anion exchanger (AER) filled in the region of the inlet side 23b1 of the desalting chamber 23b in the first embodiment. It is assumed that the same processing as the processing is performed. The to-be-processed water which flowed out from the desalination chamber 23f-1 is the desalination chamber 23f from the inlet side 23f-21 (part in which the cation exchanger CER was filled) of the desalination chamber 23f-2. -2) is passed through. In the region filled with the cation exchanger CER of the inlet side 23f-21 of the desalination chamber 23f-2, the region of the outlet side 23b2 of the desalting chamber 23b of the first embodiment is filled. It is assumed that the same treatment as that performed using the filled cation exchanger (CER) is performed. The water to be treated having passed through the region filled with the cation exchanger CER of the desalination chamber 23f-2 is passed through to the portion filled with the anion exchanger AER of the desalination chamber 23f-2. In the part filled with the anion exchanger AER of the desalination chamber 23f-2, the anion exchanger AER filled in the area | region of the exit side 23c2 of the desalination chamber 23c in 1st Embodiment It is estimated that the same processing as that performed using the above is performed.

The water to be treated that has passed through the region filled with the anion exchanger AER in the desalination chamber 23f-2 is passed through the desalting chamber 23a of the EDI apparatus 101. In the desalting chamber 23a, it is estimated that the same processing as that performed using the anion exchanger AER filled in the region on the outlet side 23c2 of the desalting chamber 23c in the first embodiment is performed. do.

Therefore, similarly to the first embodiment, the adsorption efficiency of boron (anion) by the anion exchanger (AER) filled in the desalting chamber 23a is improved. Therefore, the concentration of boron in the treated water flowing out of the desalting chamber 23a can be reduced.

Seventh Embodiment

It is a figure which shows the water treatment apparatus 207 of 7th Embodiment of this invention.

The water treatment device 207 has two EDI devices 106. Hereinafter, the EDI apparatus 106 through which the water to be treated first passes through is referred to as the "first stage EDI apparatus 106-1," and the EDI apparatus 106 through which the treated water passes through the last "end EDI apparatus 106-2. ) ".

The desalination chamber 23f-1 of the first stage EDI apparatus 106-1, the desalination chamber 23f-2 of the first stage EDI apparatus 106-1, and the final stage EDI apparatus 106-2, The desalination chamber 23f-1 and the desalination chamber 23f-2 of the final stage EDI apparatus 106-2 are connected in series in this order. The water to be treated flows in from the desalination chamber 23f-1 of the first stage EDI apparatus 106-1. Between the 1st stage EDI apparatus 106-1 and the last stage EDI apparatus 106-2, a concentration chamber is not connected in series and supply water is supplied separately. Supply water is supplied separately to the electrode chamber (cathode chamber and anode chamber) of the 1st stage EDI apparatus 106-1, and the electrode chamber (cathode chamber, anode chamber) of the last stage EDI apparatus 106-2.

Next, the water treatment performed in each desalting chamber of the water treatment apparatus 207 will be described. In the first stage EDI apparatus 106-1 and the final stage EDI apparatus 106-2, the supply water is passed through the anode chamber 21, the concentration chambers 22 and 24, and the cathode chamber 25, and the anode 11 ) And the treated water are passed through the desalination chamber 23f-1 of the first-stage EDI apparatus 106-1 while a direct current voltage is applied between

In the first stage EDI apparatus 106-1, it is estimated that the same processing as that in the EDI apparatus 106 (see FIG. 12) of the sixth embodiment is performed. The to-be-processed water which flowed out from the 1st stage EDI apparatus 106-1 passes through the desalination chamber 23f-1 of the last stage EDI apparatus 106-2. In the final stage EDI apparatus 106-2, the processing target water flowing out of the first stage EDI apparatus 106-1 is the same as the processing in the EDI apparatus 106 (see FIG. 12) of the sixth embodiment. It is assumed that the process is performed.

Therefore, the adsorption efficiency of boron (anion) by the anion exchanger (AER) filled in the region of the outlet side 23f-22 of the desalination chamber 23f-2 of the final stage EDI apparatus 106-2 is improved. This makes it possible to reduce the concentration of boron in the treated water flowing out of the desalination chamber 23f-2 of the final stage EDI apparatus 106-2.

Eighth Embodiment

14 is a diagram showing the water treatment device 208 of the eighth embodiment of the present invention.

The water treatment device 208 has an EDI device 106 and an EDI device 105. The desalination chamber 23f-1 of the EDI apparatus 106, the desalination chamber 23f-2 of the EDI apparatus 106, the desalination chamber 23e-2 of the EDI apparatus 105, and the EDI apparatus The desalination chamber 23e-1 of 105 is connected in series in this order. The water to be treated flows in from the desalination chamber 23f-1. Between the EDI apparatus 106 and the EDI apparatus 105, the enrichment chamber is not connected in series and supply water is supplied separately. Supply water is supplied separately to the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 106, and the electrode chamber (cathode chamber, anode chamber) of the EDI apparatus 105 separately.

Next, the water treatment performed in each desalting chamber of the water treatment apparatus 208 will be described. In the EDI devices 106 and 105, the 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. In one state, the water to be treated is passed through the desalination chamber 23f-1 of the EDI apparatus 106.

In the EDI device 106, it is estimated that the same processing as that in the EDI device 106 (see Fig. 12) of the sixth embodiment is performed. The to-be-processed water which flowed out from the EDI apparatus 106 passes through the desalination chamber 23e-2 of the EDI apparatus 105. FIG. In the EDI apparatus 105, it is estimated that the same processing as that in the EDI apparatus 105 (see FIG. 11) of the fifth embodiment is performed.

Therefore, the adsorption efficiency of boron (anion) by the anion exchanger (AER) filled in the desalination chamber 23e-1 of the EDI apparatus 105 is improved, and the treated water flowing out of the desalting chamber 23e-1 is improved. It is possible to reduce the concentration of boron in.

In each embodiment described above, the structure shown is an example only, and this invention is not limited to the structure.

For example, in each embodiment mentioned above, the water treatment apparatus using two EDI apparatuses is used. However, among the plurality of desalination chambers, the anion exchanger is filled in the uppermost portion of the desalting chamber at the first stage through which the water to be treated first passes and at the lowermost portion of the desalting chamber at the final stage at which the treated water is discharged, and is connected in series. If at least a cation exchanger is filled in the portion between the most upstream portion of the first stage desalination chamber and the most downstream portion of the final stage desalination chamber as part of a plurality of desalting chambers, the number of EDI apparatuses is not limited to two but three The above may be sufficient.

In each embodiment, the basic configuration (cell set) consisting of [concentration chamber (C) | anion exchange membrane (AEM) | desalting chamber (D) | cationic exchange membrane (CEM) | concentration chamber (C)] is provided between the positive electrode and the negative electrode. Is placed on. However, a plurality of such cell sets may be juxtaposed between the electrodes, and the plurality of cell sets may be electrically connected in series with one end as an anode and the other as a cathode in order to increase processing capacity.

In this case, neighboring enrichment chambers can be shared between adjacent cell sets. Therefore, as the configuration of the EDI device, the positive electrode chamber | C | AEM | D | CEM | C | AEM | D | CEM | C | AEM | D | CEM |. | C | cathode chamber] may be used. The number of demineralization chambers in such a serial EDI apparatus is also called "the number of demineralization chamber cell pairs."

In this series structure, in the desalination chamber closest to the anode chamber, the anode chamber itself can also function as a concentration chamber without interposing an independent concentration chamber between the anode chamber and the desalination chamber closest to the cathode chamber. With respect to, the cathode chamber itself can also function as an enrichment chamber without interposing the enrichment chamber between the cathode chambers. In order to suppress the power consumed by the application of the DC voltage, at least one of the concentration chamber, the anode chamber and the cathode chamber may be charged with an ion exchanger to lower the electrical resistance of the EDI apparatus.

In each embodiment, pure water was used as the supply water flowing from the cathode chamber to the anode chamber, but the supply water supplied to the cathode chamber or anode chamber may not be pure water, for example, may be treated water. In addition, the cathode chamber and anode chamber in the same EDI apparatus may not be connected or may be connected in parallel.

In each embodiment, although pure water was supplied to each concentration chamber, you may supply the process water which the EDI apparatus of a 2nd stage outputs instead of pure water. Further, the treated water output from the second stage EDI apparatus is supplied to each concentration chamber of the second stage EDI apparatus, and the water discharged from each concentration chamber of the second stage EDI apparatus is concentrated in each of the first stage EDI apparatuses. You may supply to a thread. Moreover, the to-be-processed water may be supplied to each concentration chamber of the 1st stage EDI apparatus.

[ Example ]

Next, Examples and Comparative Examples of the present invention will be described.

As an Example and a comparative example, the water treatment apparatus provided with two EDI apparatuses, and the desalination chamber of each EDI apparatus was connected in series was used. Hereinafter, of the two EDI devices, the EDI device through which the water to be treated first flows is referred to as a "first-stage EDI device", and the EDI device (final-end EDI device) through which the water to flow out from the first-stage EDI device is passed "second stage". EDI device ”.

<Examples 1 to 8>

As the water treatment apparatuses of Examples 1 to 8, the water treatment apparatuses 201 to 208 (see Fig. 20) of the first to eighth embodiments shown in Figs.

Next, the EDI apparatus 301 used by the comparative example is demonstrated.

15 is a diagram illustrating an EDI device 301. As the EDI apparatus 301, the EDI apparatus which filled the deionization chamber 23g with the anion exchanger A and the cation exchanger K in the mixed phase form was used.

Next, the water treatment apparatus of Comparative Examples 1-4 is demonstrated.

16 to 19 are diagrams showing the water treatment apparatuses of Comparative Examples 1 to 4, respectively.

In the comparative example 1, as shown in FIG. 16, the EDI apparatus 301 was used as a 1st stage EDI apparatus and a 2nd stage EDI apparatus. In the comparative example 2, as shown in FIG. 17, the EDI apparatus 301 was used as the 1st stage EDI apparatus, and the EDI apparatus 103 was used as the 2nd stage EDI apparatus. In the comparative example 3, as shown in FIG. 18, the EDI apparatus 301 was used as the 1st stage EDI apparatus, and the EDI apparatus 102 was used as the 2nd stage EDI apparatus. In the comparative example 4, as shown in FIG. 19, the EDI apparatus 101 was used as the 1st stage EDI apparatus, and the EDI apparatus 301 was used as the 2nd stage EDI apparatus.

The operating conditions such as the specifications of the EDI apparatus, the flow rate of the water flow, the applied current, and the quality of the water to be treated in Examples 1 to 8 and Comparative Examples 1 to 4 are as follows.

Cation exchange resin [Product Name: AMBERJET® 4002 (strongly basic anion exchange resin 4002), manufactured by Dow Chemical Company) as an anion exchanger, as a cation exchanger. : Amberjet (registered trademark) 1020 (strongly acidic cation exchange resin 1020) and the Dow Chemical company] were used.

In the desalting chambers 23b and 23c, the desalting chamber 23f-2, and the desalting chamber 23g filled with both of the anion exchange resin and the cation exchange resin, the ratio of the volume of the anion exchange resin and the cation exchange resin is determined. 1: 1.

The volume of the cell (desalting chamber, concentration chamber, anode chamber, cathode chamber) was set to 100 mm x 100 mm x 10 mm.

The number of desalination chamber cell pairs was 1 cell pair.

As the water to be treated to the first stage EDI apparatus, two stage RO (reverse osmosis membrane) treated water (conductivity: 3 to 4 µS / cm, boron concentration: 90 to 100 µg B / L) was used.

The water flow rate to be treated was set to 20 L / h.

The value of the current flowing between the positive electrode and the negative electrode was 0.4 A.

Pure water from a separate system was used as the feed water to be supplied to the concentration chamber.

-The flow volume of the supplied water to the concentration chamber was 5 L / h.

Pure water from a separate system was used as the supply water supplied to the anode chamber and the supply water supplied to the cathode chamber.

-The flow volume of the water to be supplied to the anode chamber and the flow rate of the water to the cathode chamber were 5 L / h.

It is a figure which shows the measurement result of the boron concentration (unit: ng B / L) of the treated water in Examples 1-8 and Comparative Examples 1-4. In FIG. 20, the state (deformation form of anion exchange resin and cation exchange resin) of the desalination chamber of each EDI apparatus is shown typically. In FIG. 20, the anion exchange resin layer is shown by "A", the cation exchange resin layer is shown by "K", and the mixed layer of anion exchange resin and cation exchange resin is shown by "MB".

As can be seen from the boron concentrations of the treated waters of Examples 1 to 8 and Comparative Examples 1 to 4, the boron concentration was 50 ng B / L or less only by connecting the desalination chambers of the two EDI apparatuses in series. I could not. Moreover, it is considered that boron concentration is 50 ng B / L or less is preferable in the pure water used by a semiconductor process, for example.

On the other hand, as in Examples 1 to 8, the anion exchange resin is filled solely in the region of the upstream portion of the desalination chamber of the first stage EDI apparatus, and the anion is formed in the region of the most downstream portion of the desalination chamber of the second stage EDI apparatus. By filling the exchange resin alone, and filling the cation exchange resin in the portion therebetween, the boron concentration could be 50 ng B / L or less.

As can be seen from the comparison between Example 1 and Examples 2 and 3, the comparison of Comparative Examples 1 to 3 and Comparative Example 4, the desalting chamber of the first stage EDI apparatus was filled with an anion exchange resin in the form of a single phase, or the second stage. By filling the desalination chamber of the EDI apparatus in the form of a single phase, the boron concentration of the treated water can be further reduced.

As can be seen from the comparison between Examples 2 to 3 and Examples 4 to 5, at least one of the desalting chambers connected in series has a desalting chamber having an intermediate ion exchange membrane, a first desalting chamber and a second desalting chamber ( It is hereinafter referred to as "D2 desalting chamber" to further reduce the boron concentration of the treated water. However, when the D2 desalination chambers are connected in series, there is a fear that the water pressure difference will increase. Therefore, as in Examples 4 to 6, if the boron concentration of the treated water can be lower than the target value (for example, 50 ng B / L) without increasing the number of D2 desalination chambers more than necessary, the surface of the water passage differential pressure There is an advantage in that.

As can be seen from the comparison between Example 7 and Example 8, the boron concentration of the treated water is further reduced by filling anion exchange resin in a single phase form in the desalination chamber at the downstream end of the final stage (second stage) EDI apparatus. I could make it.

<Examples 9 to 10>

Next, the water treatment apparatus of Examples 9 to 10 will be described with reference to FIG.

In Example 1, in Example 1, in the state which made the volume ratio of the cation exchange resin and anion exchange resin in the desalination chamber of a 2nd-stage EDI apparatus constant (cationic exchange resin: anion exchange resin = 9: 1), The volume ratio of the anion exchange resin and the cation exchange resin in the desalination chamber of the first stage EDI apparatus is changed (the volume ratio of the anion exchange resin is changed between 5% and 100%).

In Example 1, in Example 1, in the state which made the volume ratio of anion exchange resin and cation exchange resin in the desalination chamber of a 1st-stage EDI apparatus constant (anion exchange resin: cationic exchange resin = 1: 9), This is an example in which the volume ratio of the cation exchange resin and the anion exchange resin in the desalting chamber of the second stage EDI apparatus is changed (the volume ratio of the anion exchange resin is changed between 5% and 100%).

FIG. 21 is a diagram illustrating a measurement result of boron concentration of treated water in Examples 9 to 10. FIG. In addition, in FIG. 21, the state (filled form of anion exchange resin or cation exchange resin) of the desalination chamber of each EDI apparatus is shown typically, Anion exchange resin is shown by "A" and "AER", and cation exchange resin Is represented by "K".

21, in the measurement result of Example 9, when the boron concentration of the treated water when the ratio of the anion exchange resin of a 1st stage EDI apparatus is 5% is set to "1", and the ratio of anion exchange resin is increased. The degree of reduction of the boron concentration in the treated water is plotted as the removal rate. On the other hand, in the measurement result of Example 10, the process when the boron concentration of the treated water when the ratio of the anion exchange resin of a 2nd EDI apparatus is 5% is made "1", and the ratio of anion exchange resin is increased. The degree of reduction in the boron concentration of the water is plotted as the removal rate. In Examples 9 and 10, a water passage test was conducted under the same water supply load conditions as in Examples 1 to 8 and Comparative Examples 1 to 4 (for example, using two-stage RO permeated water as treated water, The boron concentration of the water to be treated passed through the desalination chamber of the first stage EDI apparatus was 90 to 100 µg B / L).

From Examples 9 and 10, it was found that the boron concentration of the treated water decreases as the ratio of the anion exchange resin increases. In addition, when comparing 5% and 10% in the ratio of anion exchange resin, it was confirmed that the degree of reduction of the boron concentration of treated water becomes remarkably larger when it is 10% than when it is less than 10%. This is the ratio of the volume of the anion exchanger charged solely to the uppermost part of the desalting chamber of the first stage to the volume of the desalting chamber of the first stage, and the lowest downstream of the desalting chamber of the final stage relative to the volume of the desalting chamber of the final stage. When the volume ratio of the anion exchanger charged solely to is 10% or more, it means that the degree of reduction in the boron concentration of the treated water is significantly increased.

In addition, when the ratio of the anion exchange resin was 50% or more, it was confirmed that the effect of the reduction in the boron concentration of the treated water was greater than in the case of the ratio of less than 10 to 50%. This is the ratio of the volume of the anion exchanger charged solely to the uppermost part of the desalting chamber of the first stage to the volume of the desalting chamber of the first stage, and the lowest downstream of the desalting chamber of the final stage relative to the volume of the desalting chamber of the final stage. When the volume ratio of the anion exchanger charged solely to is 50% or more, it means that the degree of reduction in the boron concentration of the treated water becomes more markedly.

<Examples 11 to 13>

Next, the water treatment apparatus of Examples 11 to 13 will be described with reference to FIG.

In Example 1, in Example 1, the concentration of silica and boron was constant at about 100 micrograms / liter with respect to the water to be passed through the desalination chamber of the first stage EDI apparatus (silica: 98 µg SiO ₂ / L, Boron: 97 µg B / L) is an example in which the concentration of carbonic acid (mg CO ₂ / L) was changed.

In Example 1, in Example 1, the concentrations of boron and carbonic acid were constant (boron: 97 µg B / L, carbonic acid: 5 mg CO ₂ /) with respect to the water to be treated passing through the desalination chamber of the first stage EDI apparatus. L) is an example in which the concentration (μg SiO ₂ / L) of silica is changed in the state.

In Example 1, in Example 1, the concentration of silica and carbonic acid was constant (silica: 98 µg SiO ₂ / L, carbonic acid: 5 mg CO ₂₎ with respect to the water to be treated passing through the desalination chamber of the first stage EDI apparatus. / L) is an example in which the concentration of boron (µg B / L) was changed.

FIG. 22 is a graph showing measurement results of boron concentration in treated water in Examples 11 to 13. FIG. In FIG. 22, anion exchange resin is shown by "A" and cation exchange resin is shown by "K".

From Examples 11 to 13, in the water to be treated passed through the desalination chamber of the first stage EDI apparatus, the carbonic acid concentration was 5 mg CO ₂ / L or less, the silica concentration was 100 μg SiO ₂ / L or less, and the boron concentration was 100 μg. When it is B / L or less, it can be confirmed that the boron concentration of the treated water can be set to 50 ng B / L or less.

Further, in Example 13, when the boron concentration of the water to be treated passing through the desalination chamber of the first stage EDI apparatus was approximately 200 (198) µg B / L, the current flowing between the anode and the cathode was tested at 0.8 A. As a result, the boron concentration of the treated water could not be lower than 50 ng B / L. For this reason, it was confirmed that the boron concentration of the treated water cannot be 50 ng B / L or less simply by simply increasing the current value.

<Example 14>

Next, the water treatment apparatus of Example 14 will be described with reference to FIG.

In Example 8, in Example 8, the concentrations of silica and carbonic acid were constant (silica: 101 µg SiO ₂ / L, with respect to the water to be treated passing through the desalination chamber 23f-1 of the first stage EDI apparatus). Carbonic acid: 5 mg CO ₂ / L) is an example in which the concentration of boron (µg B / L) was changed.

FIG. 23 is a view showing a measurement result of boron concentration of treated water in Example 14; FIG. In FIG. 23, anion exchange resin is shown by "A" and cation exchange resin is shown by "K".

In Examples 11 to 13, when the desalting chamber (hereinafter referred to as "D1 desalting chamber") not separated by the intermediate ion exchange membrane was connected in series, in order to make the boron concentration of the treated water be 50 ng B / L or less, 1 It turned out that the boron concentration of the to-be-processed water passed to the EDI apparatus of 1 step should be made into about 100 microgram B / L or less.

However, as shown in Examples 4 to 8, it is possible to reduce the boron concentration of the treated water by increasing the EDI apparatus having the D2 desalting chamber in the water treatment apparatus. On the other hand, in Example 14, even if the boron concentration of the to-be-processed water passed to the EDI apparatus of 1st stage is nearly 300 (298) microgram B / L higher than the boron concentration of the to-be-processed water in Example 13, It was confirmed that the boron concentration of the water could be 50ng B / L or less.

Here, the reason why the anion exchange resin is filled solely in the uppermost part of the desalting chamber connected in series will be described. When boron in the water to be treated comes into contact with the anion exchange resin as a solid base, dissociation as an anion is promoted, and as a result, the adsorption removal efficiency by the anion exchange resin is improved.

Next, the reason why anion exchange resin is filled solely in the lowermost part of the desalination chamber connected in series and at least the cation exchange resin is filled between the most upstream part and the most downstream part will be described. After removing the cation component in the water to be treated using the cation exchange resin, and passing the treated water to the anion exchange resin at the downstreammost portion, the anion exchange at the downstreammost portion without removing the cation component using the cation exchange resin. Compared with the case where the water to be treated is passed through the resin, the concentration of hydroxide ions present in the water to be treated which is passed through the anion exchange resin at the lowermost portion can be reduced, and the boron removal efficiency using the anion exchange resin is improved.

In addition, since the ion exchange resin is in the form of a phase (the form in which both the anion exchange resin and the cation exchange resin are separately filled) in the second end desalting chamber at the final stage as in Example 7, etc., the second desorption salt Drift occurs in the current flowing through the yarn. Since this drift is caused by the difference in the electrical resistance between the anion exchange resin and the cation exchange resin, a large amount of current flows to the lower electric resistance among the anion exchange resin and the cation exchange resin. On the other hand, since the anion exchange resin is filled in the single phase form in the second denitration chamber of the last stage of Example 8, compared with Example 7, it is hard to produce a drift and the removal efficiency of boron improves.

Next, the advantages of using the D2 desalting chamber will be described. As described above, the current flows in the desalting chamber in the form of a phase. Therefore, the anion exchange resin and the cation exchange resin are separately filled in two demineralization chambers of the D2 desalting chamber in a single phase rather than the anion exchange resin and the cation exchange resin in the form of a double phase. Since an electric current can be sent to this anion exchange resin efficiently, desalination efficiency improves. However, in the D2 desalting chamber, since the flow path length is about twice as large as in the D1 desalting chamber, there is a fear that the water passage differential pressure will increase. Therefore, by reducing the number of EDI apparatuses employing the D2 desalting chamber in the range in which the target boron concentration can be achieved in the treated water, it is possible to reduce the increase in the water passage differential pressure.

Here, the "upstream part of the desalination chamber" refers to the portion (constant) that first passes when the water to be treated flows into the desalination chamber, and the "downstream part of the desalination chamber" refers to when the treated water flows out of the desalination chamber to the outside. Point to the last (constant) part that passes. The uppermost part of the desalting chamber and the lowermost part of the desalting chamber do not necessarily indicate a physical up-down relationship. For example, the water to be treated flows in from the upper side of the desalting chamber and flows out from the lower side of the desalting chamber. Also included are cases.

Claims (14)

In the water treatment apparatus having a plurality of electric deionized water production apparatus,
Each of the plurality of electric deionized water production apparatuses includes a desalting chamber filled with an ion exchanger, partitioned between an anode and a cathode by an anion exchange membrane located on the anode side and a cation exchange membrane located on the cathode side,
Each of the desalination chambers of the plurality of electric deionized water production apparatuses is in series communication,
The plurality of desalination chambers communicated in series pass through the water to be treated containing boron, and outflow of the water to be treated.
The anion exchanger is filled in the uppermost part of the desalination chamber of the first stage through which the water to be treated first passes, and the most downstream part of the desalting chamber of the final stage from which the treated water flows out.
As a part of the plurality of desalting chambers, at least a cation exchanger is filled in a portion between the most upstream portion of the desalting chamber at the first stage and the most downstream portion of the desalting chamber at the final stage,
The ratio of the volume of the anion exchanger charged solely to the uppermost part of the desalting chamber of the first stage to the volume of the desalting chamber of the first stage, and the desalting chamber of the final stage relative to the volume of the desalting chamber of the final stage. The water treatment apparatus in which the ratio of the volume of the anion exchanger packed solely in the downstreammost portion is 10% or more. The water treatment apparatus according to claim 1, wherein an anion exchanger is filled in a single phase in the desalting chamber of the first stage or the desalting chamber of the final stage. The method of claim 1, wherein at least one of the plurality of desalination chambers is
An intermediate ion exchange membrane positioned between the anion exchange membrane and the cation exchange membrane,
A first desalination chamber partitioned by the anion exchange membrane and the intermediate ion exchange membrane,
A second desalination chamber partitioned by the cation exchange membrane and the intermediate ion exchange membrane;
The water treatment apparatus in which the first desalination chamber and the second desalination chamber are connected in series. The method of claim 3,
The first stage desalination chamber includes the intermediate ion exchange membrane, the first desalination chamber, and the second desalination chamber,
In the first stage desalination chamber, the first denitration chamber is located upstream from the second desalination chamber, and the first deoxidation chamber is filled with an anion exchanger in the form of a single phase. The desalting chamber of the final stage comprises the intermediate ion exchange membrane, the first desalting chamber and the second desalting chamber,
In the desalting chamber of the last stage, the first desalination chamber is located downstream from the second desalination chamber, and the first deoxidation chamber is filled with an anion exchanger in the form of a single phase. The apparatus according to claim 3, wherein at least two electric deionized water production devices are installed,
The desalting chambers of the first stage and the final stage each include the intermediate ion exchange membrane, the first deoxidation chamber and the second desalination chamber,
In the desalting chambers of the first stage and the final stage, the first deoxidation chamber is located upstream from the second desalination chamber, and the first deoxidation chamber is filled in an anion exchanger in a single phase form, and the second The water treatment apparatus in which the cation exchanger is filled by the uppermost part in the desalination chamber alone, and the anion exchanger is filled by the parts other than the uppermost part in the second desalination chamber alone. The method according to any one of claims 3 to 5,
Two or more electric deionized water production devices are installed,
The desalting chambers of the first stage and the final stage each include the intermediate ion exchange membrane, the first deoxidation chamber and the second desalination chamber,
In the first stage desalination chamber, the first deoxidation chamber is located upstream from the second desalination chamber, and the first deoxidation chamber is filled with an anion exchanger in the form of a single phase, The cation exchanger is filled solely in the uppermost part of the cell, and the anion exchanger is filled in the part other than the uppermost part in the second desalination chamber alone.
In the desalting chamber of the final stage, the first desalination chamber is located downstream from the second desalination chamber, and the first deoxidation chamber is filled with an anion exchanger in the form of a single phase, A water treatment device in which a cation exchanger is filled in a single phase form. The water treatment apparatus according to claim 1, wherein a reverse osmosis membrane device is provided upstream of said first stage desalination chamber. The water treatment apparatus according to claim 1, wherein a decarbonate film forming apparatus is provided on an upstream side of the first stage desalination chamber. And a plurality of electric deionized water production apparatuses having a desalting chamber filled with an ion exchanger between an anode and a cathode, the anion exchange membrane located on the anode side and the cation exchange membrane located on the cathode side, the ion exchanger being filled. Each of the desalination chambers of the electric deionized water production apparatus is connected in series, and the plurality of desalination chambers connected in series pass through the water to be treated containing boron to drain the treated water, and the water to be treated first passes through. The anion exchanger is filled in the uppermost part of the first desalting chamber of the first stage and the most downstream part of the desalting chamber of the final stage of distilling the treated water. At least the cation exchanger is filled in the portion between the most upstream part of the yarn and the most downstream part of the desalting chamber of the final stage, and the desalting of the first stage The ratio of the volume of the anion exchanger alone charged to the uppermost portion of the desalting chamber at the first stage to the volume of, and the lowest downstream of the desalting chamber at the final stage relative to the volume of the desalting chamber at the final stage. The ratio of the volume of the purified anion exchanger is a water treatment method using a water treatment apparatus that is 10% or more,
A water treatment method for flowing out the treated water by passing the treated water through a plurality of desalination chambers connected in series while applying a DC voltage between the anode and the cathode. 11. The method of claim 10, wherein the silica concentration of the water to be treated to the water flow electric deionized water producing apparatus of the first-stage 100㎍ SiO ₂ / L or less, the water treatment method. The water treatment method of Claim 10 whose boron concentration of the to-be-processed water passed to the said 1st stage electric deionized water manufacturing apparatus is 100 micrograms B / L or less. The water treatment method according to any one of claims 10 to 12, wherein the carbonic acid concentration of the water to be treated passed to the first stage electric deionized water production apparatus is 5 mg CO ₂ / L or less. The apparatus of claim 10, wherein at least two electric deionized water production apparatus is installed,
The desalination chambers of the first stage and the final stage each include an intermediate ion exchange membrane, a first desalination chamber and a second desalination chamber,
In the desalting chambers of the first stage and the final stage, the first deoxidation chamber is located upstream from the second desalination chamber, and the first deoxidation chamber is filled in an anion exchanger in a single phase form, and the second The water treatment method in which the cation exchanger is filled by the uppermost part in the desalination chamber alone, and the anion exchanger is filled by the parts other than the uppermost part in the second desalination chamber alone.

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