JP2001327971A - Electro-deionizing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electro-deionizing apparatus capable of markedly reducing the concentrations of silica and boron in desalted water. SOLUTION: In the electro-deionizing apparatus wherein a plurality of anion exchange membranes 13 and a plurality of cation exchange membranes 14 are alternately arranged between a cathode 12 and an anode 11 to alternately form concentration chambers 15 and desalting chambers, each of the desalting chambers are demarcated into a first chamber 1 on the side of the anode 11 and a second chamber 2 on the side of the cathode 12 by an anion exchange membrane 3 and water to be treated flows through the second chamber 2 from the first chamber 1 through a flow channel 4. The first chamber is filled with an anion exchanger and the second chamber is filled with a cation exchanger.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric device comprising a plurality of anion exchange membranes and a plurality of cation exchange membranes arranged alternately between a cathode and an anode to alternately form a concentration chamber and a desalination chamber. The present invention relates to a deionization apparatus, and more particularly to an electrodeionization apparatus capable of sufficiently reducing the concentration of a silica component or a boron component by improving the configuration of a deionization chamber.

[0002]

2. Description of the Related Art FIG. 2 (a) shows the production of deionized water used in various industries such as a semiconductor manufacturing plant, a liquid crystal manufacturing plant, a pharmaceutical industry, a food industry, an electric power industry, or a consumer or research facility. As shown in the figure, the electrodes (anode 11, cathode 1
During 2), a plurality of anion exchange membranes 13 and cation exchange membranes 14 are alternately arranged to form a concentration chamber 15 and a desalination chamber 16 alternately. An electrodeionization apparatus is used in which an anion exchanger and a cation exchanger, such as a graft exchanger, are mixed or filled in a multi-layer form (Japanese Patent No. 178294).
No. 3, Patent No. 2,751,090, Patent No. 2,699,256
issue). In this electrodeionization apparatus, the water to be treated is supplied to and passes through both the desalting chamber 16 and the concentrating chamber 15, while the water being treated in the desalting chamber 16 during this time as shown in FIG. The cation component moves toward the anode 11, passes through the cation exchange membrane, and moves to the concentration chamber on the anode side. Also,
The anion component in the desalting chamber 16 moves toward the cathode 12, passes through the anion exchange membrane, and moves to the concentration chamber on the cathode side. As a result, the effluent from the desalination chamber becomes deionized water and the effluent from the concentration chamber becomes concentrated water. In FIG. 2A,
Reference numeral 17 denotes an anode chamber, and 18 denotes a cathode chamber.

[0003] The electrodeionization apparatus uses water to dissociate H ⁺
Ions and OH ^- to produce ions, by continuously reproducing ion exchanger filled in the desalting compartment,
Efficient desalination treatment is possible, and complete continuous water sampling is possible without the need for regeneration treatment using chemicals such as ion exchange resin equipment that has been widely used in the past. It has an excellent effect of being obtained.

[0004]

As a result of various studies, it has been found that, in the conventional electrodeionization apparatus, silica ions (eg, HSiO ₃ ⁻ ) and borate ions (eg, HBO ₃ ⁻ ) are used.
Was found to be slightly inadequate.

[0005] An object of the present invention is to provide an electrodeionization apparatus capable of obtaining treated water (desalinated water) having a sufficiently low silica concentration and low boron concentration.

[0006]

According to the electrodeionization apparatus of the present invention, a plurality of anion exchange membranes and cation exchange membranes are alternately arranged between a cathode and an anode to form a concentration chamber and a desalination chamber. In an electrodeionization apparatus formed alternately and filled with an ion exchanger in the desalting chamber, the desalting chamber is divided into a first chamber on the anode side and a second chamber on the cathode side by an anion exchange membrane. The first chamber is filled with an anion exchanger and the second
The chamber is filled with a cation exchanger, and the outlet of the first chamber is communicated with the inlet of the second chamber so that the effluent of the first chamber flows to the second chamber. is there.

In the electrodeionization apparatus of the present invention as well, the water to be treated is introduced into both the desalting chamber and the concentrating chamber, and the water passes through these chambers. From the deionization chamber, the deionized water is taken out from the deionization chamber, and the concentrated water is taken out from the concentration chamber.

In the present invention, the desalting chamber is divided by the anion exchange membrane into a first chamber on the anode side and a second chamber on the cathode side, and in the vicinity of the anion exchange membrane (on the anode side) in the second chamber. As OH ^- is generated, OH ^- ions are supplied from the second chamber to the first chamber (through the anion exchange membrane between the two chambers). As a result, transfer of anions from the first chamber to the concentration chamber on the anode side is promoted. As a result, the concentrations of silica and boric acid in the demineralized water become significantly lower than in the past.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electrodeionization apparatus according to an embodiment will be described with reference to FIG.

Also in this embodiment, a plurality of anion exchange membranes 13 and cation exchange membranes 14 are alternately arranged between the anode 11 and the cathode 12, so that the concentration chamber 15 and the desalination chamber are formed alternately. .

In this embodiment, the desalting chamber 1
The inside of the first chamber 1 on the side of the anode 11 is formed by the anion exchange membrane 3.
The first chamber 1 is filled with an anion exchanger, and the second chamber 2 is filled with a cation exchanger. The outlet of the first chamber 1 and the inlet of the second chamber 2 are connected by a flow path 4. The concentration chamber 15 is filled with an anion exchanger and a cation exchanger (in FIG. 1, it is indicated as a MIX exchanger). Reference numeral 17 denotes an anode chamber, 1
8 denotes a cathode chamber.

In the electrodeionization apparatus thus configured, the water to be treated is introduced into both the desalting chamber 16 (first chamber 1) and the enrichment chamber 15, and the water to be treated is introduced into these chambers 15, 15.
In the meantime, ions move from the desalting chamber 16 to the concentrating chamber 15 side, deionized water is taken out from the desalting chamber 16 (second chamber 2), and concentrated water is taken out from the concentrating chamber. It is.

Further, the OH flows from the second chamber 2 to the first chamber 1.
^- ions is supplied through the anion exchange membrane 3 between the chambers 1 and 2, the silica ions and borate ions concentrating chamber 15
The demineralized water that efficiently moves to the side and has a low silica concentration and a low boron concentration is taken out of the desalting chamber (second chamber 2) 16.

In the first chamber 1, anions such as silica and boron components efficiently move to the concentration chamber 15 on the anode 11 side via the anion exchanger. Therefore, the first room 1
It is most efficient that only the anion exchanger is filled with the ion exchanger.

The treated water passes through the second chamber 2 after leaving the first chamber 1. Here, trace amounts of silica and boron components are removed, but the amounts are very small. The action of the second chamber 2, OH generated by the dissociation of water ^- ions of the first chamber 1
To improve the removability of silica and boron in the first chamber 1. Research has shown that water dissociation occurring in the anion exchange membrane 3 on the anode side of the second chamber 2 is most likely to proceed when a cation exchanger is present in the second chamber and an anion exchanger is present in the first chamber. Was. Therefore, the second chamber 2 is filled with a cation exchanger. The reason why water dissociation is likely to occur in this manner is not clear, but the action of attracting OH ⁻ ions to the anode 11 is provided by the anion exchanger 1 and the action of attracting H ⁺ ions to the cathode 12 is the action of the cation exchanger. It is presumed that this would be caused by 2.

In the concentration chamber 15 on the anode 11 side of the first chamber 1, silica ions and borate ions are concentrated.
Since the raw water has a high specific resistance and contains few ions, it is filled with an ion exchanger to reduce the electric resistance. The ion exchanger here may be a mixture of an anion exchanger and a cation exchanger, or may be a layer in which an anion exchanger and a cation exchanger are alternately packed in a multilayer, and there is no particular limitation. .

However, when the two were compared, the electric resistance tended to be smaller when the anion exchanger and the cation exchanger were alternately packed in multiple layers. It is preferable to alternately fill multiple layers.

With the apparatus of the present invention, the silica removal rate is 99%.
% Or more, and the boron removal rate can be 98% or more. Such an electrodeionization apparatus for the purpose of polishing silica and boron can be used, for example, in the final stage of a primary pure water facility.

Further, when a secondary pure water facility is provided after the primary pure water facility, the apparatus of the present invention can be installed after the UV oxidation device of the secondary pure water facility. In this case, the TOC component (organic carbon) generated by UV oxidation can be sufficiently removed by the apparatus of the present invention.

By incorporating the apparatus of the present invention into such an ultrapure water facility, the load of silica and boron on the deminer (non-regenerative ion exchange apparatus) of the secondary pure water in the secondary pure water facility is almost eliminated. In addition, the service life of the deminer is several years or more, or the deminer is not required, and the maintenance of the ultrapure water apparatus is significantly reduced.

[0021]

As described above, according to the electrodeionization apparatus of the present invention, it is possible to efficiently produce demineralized water having extremely low silica and boron concentrations.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an electrodeionization apparatus according to an embodiment.

FIG. 2 is a schematic sectional view showing a conventional electrodeionization apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st chamber 2 2nd chamber 3 Anion exchange membrane 4 Flow path 10 Ion exchanger 11 Anode 12 Cathode 13 Anion exchange membrane 14 Cation exchange membrane 15 Concentration room 16 Demineralization room 17 Anode room 18 Cathode room

Continued on the front page F-term (reference) 4D006 GA17 HA47 JA30A JA41A JA43A JA44A KA31 KA64 KB11 MA03 MA13 MA14 MB07 PA01 PB02 PB07 PB23 PB28 PC01 PC03 PC04 PC11 PC42 4D061 DA02 DB13 EA09 EB01 EB04 EB13 EB17 EB19 FA

Claims (1)

[Claims] An anion exchange membrane and a cation exchange membrane are alternately arranged between a cathode and an anode to form a concentration chamber and a desalination chamber alternately. The deionization chamber is partitioned by an anion exchange membrane into a first chamber on the anode side and a second chamber on the cathode side, and the first chamber is filled with an anion exchanger. The second chamber is filled with a cation exchanger, and the outlet of the first chamber is communicated with the inlet of the second chamber so that the effluent of the first chamber flows to the second chamber. Characteristic electrodeionization device.