WO2011093296A1

WO2011093296A1 - Ion exchange film, ion exchange body, ion exchange unit, ion exchange device, and water treatment device using ion exchange device

Info

Publication number: WO2011093296A1
Application number: PCT/JP2011/051397
Authority: WO
Inventors: 利明平井
Original assignee: パナソニック電工株式会社
Priority date: 2010-01-26
Filing date: 2011-01-26
Publication date: 2011-08-04
Also published as: JP2011152489A

Abstract

Ion exchange fibers (23a, 24a) which have an ion exchange group on at least the surface are layered like a non-woven fabric, thus forming ion exchange films (23, 24) which have an ion exchange functionality and are resistant to swelling in water.

Description

Ion exchange membrane, ion exchanger, ion exchange unit, ion exchange device, and water treatment device using the ion exchange device

The present invention relates to an ion exchange membrane, an ion exchanger, an ion exchange unit, an ion exchange device, and a water treatment device using the ion exchange device.

Conventionally, a strongly acidic cation exchange fiber, a strongly basic anion exchange fiber, and a desalting chamber of an electrodialysis apparatus in which an anion exchange membrane and a cation exchange membrane are alternately arranged between an anode chamber and a cathode chamber There is known a pure water production apparatus containing a filler made of a mixture of inert synthetic fibers (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 7-236889

In the above-mentioned prior art, although an anion exchange membrane and a cation exchange membrane are used, these ion exchange membranes have a high water-swelling property. As described above, when the ion exchange membrane having a high water-swelling property is assembled in a dry state, there is a problem that the ion exchange membrane is deformed when it is filled with water.

Therefore, in the case of using an ion exchange membrane having high water-swelling property, it is necessary to assemble the ion exchange membrane in a state of being impregnated with water in the apparatus, which takes time and effort.

Then, an object of the present invention is to obtain an ion exchange membrane, an ion exchanger, an ion exchange unit, an ion exchange device, and a water treatment device using the ion exchange device, which can be assembled more easily.

The main feature of the present invention is to use an ion exchange membrane which has an ion exchange function and is hardly swellable to water.

According to the present invention, since the ion exchange membrane is hardly swellable in water, even if the ion exchange membrane is assembled in a dry state and then the water is impregnated in the ion exchange membrane, the ion exchange is performed. It is possible to prevent the membrane from being deformed. Therefore, it is not necessary to impregnate the ion exchange membrane with water, and the ion exchange membrane can be more easily assembled into the apparatus.

FIG. 1 is an explanatory view schematically showing a water treatment apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an ion exchange apparatus according to an embodiment of the present invention. FIG. 3 is a view schematically showing an ion exchange membrane, a cathode and an anode according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing a modification of the ion exchange apparatus according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The water treatment apparatus 10 according to the present embodiment includes a water passage 11. As shown in FIG. 1, the water passage 11 is connected to a water pipe (not shown) or the like via a water supply valve 12. In this embodiment, the pre-filter 13, the secondary filter 15, the adsorption filter 16, the ion exchange device 18 and the post filter 19 are arranged in the water flow passage 11 sequentially from the upstream side (arrangement side of the water supply valve 12) to the downstream side. It is arranged in series. And while the pressure rising pump 14 is arrange | positioned between the pre filter 13 and the secondary filter 15, the non-return valve 17 is arrange | positioned between the adsorption filter 16 and the ion exchange apparatus 18. FIG.

The water introduced into the water treatment apparatus 10 through the water supply valve 12 is first introduced into the prefilter 13.

The pre-filter 13 is, for example, a sponge-like filter (not shown) or the like for capturing and removing relatively large foreign matter mixed in water.

Although this pre-filter 13 is for preventing the decrease of the pump capacity due to the mixing of the fine particles into the inside of the pressure rising pump 14, it is not necessary to provide it in particular.

The water that has passed through the pre-filter 13 and reached the pressure rising pump 14 is pressure-increased by the pressure rising pump 14 and introduced into the secondary filter 15 and the adsorption filter 16.

For example, a hollow fiber membrane (not shown) or the like is used as the secondary filter 15, and when water passes through the hollow fiber membrane, fine particle components (turbidity components) which are foreign substances mixed in water are Capture and filter. The secondary filter 15 can also be configured using a reverse osmosis membrane such as an NF membrane or an RO membrane, or a filtration membrane such as a UF membrane, an MF membrane, etc. When a membrane filter unit of a reverse osmosis membrane is used And a discharge pipe for discharging the concentrated water.

In addition, it is also possible to arrange the prefilter 13 and the secondary filter 15 in multiple places, respectively. In that case, it is preferable to dispose the filter so that the pore size decreases from the upstream toward the downstream.

The adsorption filter 16 contains, for example, activated carbon, and removes components dissolved in water, particularly off-flavors and off-flavors, or halogenated carbon such as trihalomethane. In addition, by mixing a heavy metal removing agent for removing heavy metals into the inside of the adsorption filter 16, harmful heavy metals such as lead may be adsorbed and removed. Further, since the residual chlorine in the water is decomposed and removed by the adsorption filter 16, bacteria are easily propagated downstream. Therefore, it is preferable to mix an antibacterial agent containing an antibacterial metal such as silver in the adsorption filter 16.

Then, the water that has passed through the adsorption filter 16 is introduced into the ion exchange device 18 via the check valve 17.

Then, cations and anions in the water are removed by the ion exchange device 18, and water with little salt content is introduced into the post filter 19. Further, the concentrated water in which the cation and the anion are concentrated is discharged to the outside of the apparatus through the

drains

32a and 32b.

The details of the ion exchange device 18 will be described later.

Then, the water introduced into the post filter 19 is discharged to the outside from the downstream end of the water passage 11 in a state where the taste and odor component in the water are finally removed by the post filter 19 and the taste is adjusted. Be done. The downstream end of the water passage 11 is connected to a faucet or the like, and treated water is supplied via the faucet or the like.

The post filter 19 also has a function of suppressing the mixing of the filter material or the like into the supplied treated water even if the filter material or the like leaks.

The non-return valve 17 remains from the downstream side including the ion exchange device 18 when the pressure rising pump 14 is stopped, or when the water supply valve 12 is closed or when the water pressure of the water pipe drops to a predetermined pressure or less. The pressure prevents the backflow of water, and the foreign substances accumulated and accumulated in the filter such as the prefilter 13 are prevented from flowing back to the water pipe.

With such a configuration, it is possible to miniaturize the water treatment apparatus capable of supplying the drinking water desalted even from the raw water of high hardness.

In addition, a water treatment apparatus is not limited to the said structure.

For example, a pressure sensor is provided, and when the water passage 11 is pressurized to a predetermined pressure or more, the pressure sensor sends a signal to a control unit (not shown) that controls the pressure pump 14 and the water supply valve 12 to stop the pressure pump 14 In addition, the water supply valve 12 may be configured to be closed. In this way, it is possible to prevent water leakage and damage due to abnormal pressure increase inside the water passage 11.

Furthermore, it is also possible to provide a water quality sensor in the water passage 11 or the like and to stop the water supply when the water quality is abnormal.

In addition, the convenience of the user may be improved by storing and fixing the water treatment device 10 in a housing so that the housing can be installed in the vicinity of the treated water use location.

In the water treatment apparatus 10, the pre-filter 13 is disposed upstream of the pressure pump 14, but the pre-filter 13 does not have to be disposed upstream of the pressure pump 14, and the downstream of the pressure pump 14 is not required. It may be arranged on the side. Furthermore, if there is a possibility that particles that may interfere with the operation of the water supply valve 12 may be mixed, the pre-filter 13 may be disposed upstream of the water supply valve 12.

In addition, the mounting position of the check valve 17 is not limited, and if there is a case where the operation of the pressure pump 14 and the water supply valve 12 may be disturbed by the back pressure generated at the time of water stop, a place necessary for the avoidance. It should be placed in

Next, the ion exchange device 18 will be described.

As shown in FIG. 2, the ion exchange device 18 according to the present embodiment is formed by arranging the ion exchange unit 20 having an ion exchange function in the casing 30, and can be detachably attached to the water treatment device 10. It can be worn.

The casing 30 has a substantially cylindrical shape, and a suction port 31 a for introducing water into the casing 30 is formed in a substantially central portion of the bottom wall portion 31. The top wall portion 32 is provided with a concentrated water discharge port 32b substantially at the center and a concentrated water discharge port 32a at the outer peripheral portion. An outlet 32c is provided.

In addition, although the casing 30 attaches the top wall part 32 grade | etc., So that attachment or detachment is possible, the ion exchange unit 20 can be arrange | positioned inside, but such a structure is abbreviate | omitted in FIG.

In the present embodiment, the ion exchange unit 20 includes the substantially cylindrical ion exchanger 21, and the anode 27 is provided radially inward (in one direction) on the radially inner side of the ion exchanger 21 (in one direction). The cathode 28 is disposed on the outer peripheral side. As described above, in the present embodiment, the ion exchange unit 20 is formed by arranging the anode 27 and the cathode 28 at both ends in the radial direction (one direction) of the ion exchanger 21 so as to sandwich the ion exchanger 21. ing.

The ion exchanger 21 includes an ion exchange layer (ion exchange portion having an ion exchange function) 22 obtained by forming at least a mixture of cation exchange fibers and anion exchange fibers in a substantially cylindrical shape. . Then, the anion exchange thin layer (ion exchange membrane) 23 is laminated on the radially inner peripheral side of the ion exchange layer 22 and the cation exchange thin layer (ion exchange membrane) 24 is laminated on the radial outer peripheral side. ing.

That is, the ion exchanger 21 comprises an ion exchange layer (ion exchange portion having an ion exchange function) 22, an anion exchange thin layer (ion exchange membrane) 23 and a cation exchange thin layer (ion exchange membrane) 24. It is formed by sandwiching from the radially inner and outer peripheral side.

Furthermore, in the present embodiment, the permeable reinforcing material 25 for maintaining the shape of the anion exchange thin layer (ion exchange membrane) 23 is provided on the radially inner peripheral side of the anion exchange thin layer (ion exchange membrane) 23. It is stacked. A permeable reinforcing material 26 for maintaining the shape of the cation exchange thin layer (ion exchange membrane) 24 is laminated on the radially outer peripheral side of the cation exchange thin layer (ion exchange membrane) 24.

In the present embodiment, the anode 27 and the cathode 28 described above are respectively laminated on the radially inner peripheral side of the reinforcing material 25 and the radial outer peripheral side of the reinforcing material 26.

And both ends in the axial direction (vertical direction in FIG. 2) of the ion exchange unit 20 are covered with

end caps

40 and 41.

In the bottom wall 40 a of the end cap 40, a plurality of suction ports 40 b for introducing water into the ion exchange unit 20 are formed in the circumferential direction.

A groove 41b is formed along the circumferential direction on the lower surface side of the top wall 41a of the end cap 41, and a part of the groove 41b penetrates to communicate with the deionized water discharge port 32c. 41c is formed.

In the present embodiment, the diameter and axial length of the casing 30 are made longer than the diameter and axial length of the ion exchange unit 20. Then, the central hollow portion of the ion exchange unit 20 communicates with the concentrated water discharge port 32b of the top wall 32 of the casing 30, and the communication port 41c communicates with the deionized water discharge port 32c. The wall 41 a is attached to the top wall 32 of the casing 30. At this time, the concentrated water passage 30 a is formed on the outer peripheral side than the ion exchange unit 20 of the casing 30, and the concentrated water passage 30 b is formed on the inner peripheral side of the ion exchange unit 20 of the casing 30. The

concentrated water passages

30a and 30b respectively communicate with the concentrated

water discharge ports

32a and 32b.

At this time, it is preferable that the communication port 41 c and the deionized water discharge port 32 c be in fluid tight communication.

Here, in the present embodiment, an ion exchange membrane having an ion exchange function and being hardly swellable with water, an anion exchange thin layer (ion exchange membrane) 23 and a cation exchange thin layer (ion exchange membrane) ) Is used.

Specifically, a very fine fiber (a fiber having an ion exchange function on at least the surface) coated with a polymer having a functional group having an ion exchange function branched from the main chain on the outer surface of a water-swellable polymer. The anion exchange thin layer (ion exchange membrane) 23 and the cation exchange thin layer (ion exchange membrane) 24 are formed by laminating 23a and 24a in a non-woven fabric state (see FIG. 3).

When the anion exchange thin layer (ion exchange membrane) 23 is formed, a polymer having a basic functional group such as dimethylaminoethyl group is used. Moreover, when forming the cation exchange thin layer (ion exchange membrane) 24, the polymer which has acidic functional groups, such as a carboxyl group, is used.

In the present embodiment, fibers having an average fiber diameter of less than 1 μm, more preferably 100 nm or less, are used as the

fibers

23a and 24a. Then, by laminating the fibers so that the fiber density is 10 mg / cm 2 or more, the anion exchange thin layer (ion exchange membrane) 23 and the cation exchange thin layer (ion exchange membrane) 24 are formed in a non-woven fabric shape doing.

As described above, since the anion exchange thin layer (ion exchange membrane) 23 and the cation exchange thin layer (ion exchange membrane) 24 according to the present embodiment are formed of fibers with an extremely small fiber diameter, the fiber gap is also formed. It is a porous membrane provided with a large number of fine pores having a fiber diameter or less.

In addition, since this fibrous film has an extremely thin diameter, it has flexibility, and the fiber layer can be easily formed on the surface of another material serving as a base material. Therefore, when the fiber membrane is laminated on the surface of the porous filter medium, it is possible to capture the fine particles having the opposite charge and prevent the surface of the filter medium from being contaminated by the fine particles. Moreover, if the metal film (for example, Ag etc.) which has antimicrobial property is carry | supported by a fiber membrane, the contamination by the microorganisms of the filter material surface can be suppressed.

Furthermore, in the present embodiment, an anion exchange thin layer (ion exchange membrane) 23 and a cation exchange thin layer (ion exchange membrane) are laminated in a non-woven fabric state in which fibrous polymers of poorly swellable polymers with respect to water are made. And 24). Therefore, the deformation of the fiber itself is extremely small in the dry state and in the state of being impregnated with water, and the ion exchange membrane itself becomes hardly swellable with water.

Further, since the non-woven fabric is laminated, even if the fibers swell, it is possible to suppress the swelling of the film itself only by changing the free end position of the fibers.

In addition, since the surface is coated with a polymer having a functional group having an ion exchange function, the poor swelling property to water can be further enhanced.

The material of the polymer hardly swellable to water can be arbitrarily selected from those which can be processed into fibers such as polyesters, amides, vinyls and acrylics.

In addition, the material of the polymer having a functional group having an ion exchange function can be arbitrarily selected from those having an ion exchange function, such as a cellulose type and a styrene type.

The

fibers

23a and 24a, for example, apply static electricity to the core material using a polymer that does not easily swell in water as the core material, and apply a reverse potential to the core material with a polymer having an ion exchange function from a fine diameter nozzle It is formed by spouting in the state.

At this time, it is preferable that the nozzle having a double tube structure is used to eject the hardly swellable polymer with respect to water from the center side and eject the polymer having an ion exchange function from the outer peripheral side.

Further, in the present embodiment, the anode 27 and the cathode 28 (at least one of the anode and the cathode) are formed of the

conductive fibers

27a and 28a.

Like the anion exchange thin layer (ion exchange membrane) 23 and the cation exchange thin layer (ion exchange membrane) 24, the anode 27 and the cathode 28 are formed by laminating

conductive fibers

27a and 28a in a non-woven cloth state. (See Figure 3). In addition, in FIG. 3, what abbreviate | omitted the reinforcing

materials

25 and 26 is illustrated for convenience.

The material of the

conductive fibers

27a and 28a is metal fibers having corrosion resistance such as platinum and gold, various types of polymers containing carbon fibers and carbon as a filler, for example, polyamide based such as nylon, acrylic such as polymethyl methacrylic acid It can be widely selected from materials having conductivity, such as olefins such as polyesters, polyesters, vinyls and polyethylenes.

Thus, forming the anode 27 and the cathode 28 with the

conductive fibers

27a and 28a improves the degree of freedom in processing and shape as compared with the case of using a rod-like metal lump or a plate-like electrode. The shape freedom of the ion exchange unit 20 can also be improved.

Further, by forming the

conductive fibers

27a and 28a, it becomes possible to coat the surface of the base material, and there is no need to fix the electrode itself, so that the configuration of the ion exchange unit 20 can be simplified.

As usual, a metal plate of stainless steel, titanium, platinum, iridium or the like provided with a hole may be used as an electrode (anode and cathode).

Next, the operation of the ion exchange device 18 will be described.

First, the water introduced into the casing 30 (ion exchange device 18) from the suction port 31a flows through the outer peripheral portion (concentrated water passage 30a) of the casing 30 and the inner peripheral portion of the casing 30 (concentrated water passage 30b) And water introduced into the inside of the ion exchange layer 22 from the suction port 40 b provided on the bottom wall 40 a of the end cap 40.

At this time, a plate or the like for dispersing the water introduced from the suction port 31a may be arranged to divert the water more evenly.

Then, when a voltage (DC) is applied to the anode 27 and the cathode 28, ions having opposite charges are electrically attracted to the respective electrodes (the anode 27 and the cathode 28).

At this time, cations such as calcium, magnesium, sodium and potassium are adsorbed by ion exchange on the cation exchange fiber mixed in the ion exchange layer 22. Here, since the cation adsorbed to the cation exchange fiber by ion exchange is electrically attracted to the cathode 28, it moves to the outer peripheral side of the ion exchange layer 22 while repeatedly attaching and detaching to the cation exchange fiber. .

On the outer periphery of the ion exchange layer 22, a cation exchange thin layer (ion exchange membrane) 24 composed of fibers 24a is present. As described above, this cation exchange thin layer (ion exchange membrane) 24 is composed of microfibers 24a at least the surface of which has a diameter of less than a micron having anion exchange ability, and the gaps between the fibers are further reduced It has a water-permeable structure.

Since this cation exchange thin layer (ion exchange membrane) 24 is formed using the nano-sized fibers 24a, its specific surface area is remarkably wider than that of the same weight and the same material, and the reactivity is low. It is very expensive.

Therefore, this cation exchange thin layer (ion exchange membrane) 24 also adsorbs cations quickly. Then, the cations adsorbed on the cation exchange thin layer (ion exchange membrane) 24 are attracted to the cathode 28 present on the outer periphery and move toward the cathode 28 through the relatively large through holes of the reinforcing material 26. Then, it is discharged as concentrated water from the concentrated water discharge port 32 b to the outside of the ion exchange device 18.

Further, anions such as sulfate ion, chloride ion, nitrate ion, phosphate ion and the like which flow into the ion exchange layer 22 are also anion exchange fiber and anion exchange thin layer (ion exchange membrane) 23 inside the ion exchange layer 22. Move while repeatedly removing and attaching. That is, the anions move to the side of the anode 27 which is in the opposite direction (radial direction inner circumferential side) to the above-mentioned cations, and are discharged as concentrated water from the concentrated water discharge port 32 b to the outside of the ion exchange device 18.

Thus, the deionized water from which the ion component in the water has been removed is discharged from the deionized water discharge port 32c through the communication port 41c formed in the groove 41b.

In addition, since the anion exchange thin layer (ion exchange membrane) 23 and the cation exchange thin layer (ion exchange membrane) 24 form a layer of

nano size fibers

23a and 24a, the pore diameter of the hole communicated on both sides Can also be very small holes of nano size. Therefore, the water flowing through the outer peripheral portion of the casing 30 and the water flowing through the inner peripheral portion of the casing 30 can be prevented from moving into the ion exchange layer 22.

In addition, as shown in FIG. 4, it is also possible to use what was equipped with multiple ion exchange units 20 as the ion exchange apparatus 18. In FIG.

In FIG. 4, what arrange | positioned three ion exchange units 20 concentrically is shown.

Then, the cation exchange thin layer 24 and the cathode 28 are provided on the radially outer peripheral side of each ion exchange layer 22, and the anion exchange thin layer 23 and the anode 27 are provided on the radially inner peripheral side of each ion exchange layer 22. Is provided. In addition, a deionized water collecting channel 50 is provided to further connect the deionized water discharge ports 32c provided on the end cap 41 to which the ion exchange units 20 are integrally fixed.

Then, deionized water generated through each of the ion exchange units 20 is discharged through the deionized water collecting channel 50. In addition, the concentrated water generated at this time is also discharged to the outside of the ion exchange device 18 through the concentrated water collection channel 51.

With such a configuration, the highly efficient ion exchange device 18 can be made more compact.

As described above, in the present embodiment, the anion exchange thin layer (ion exchange membrane) 23 and the cation exchange thin layer (ion exchange membrane) have ion exchange function and are hardly swellable in water. It used as an ion exchange membrane) 24. Therefore, the anion exchange thin layer (ion exchange membrane) 23 and the cation exchange thin layer (ion exchange membrane) 24 assembled in a dry state can be prevented from being deformed when impregnated with water. . Thus, according to the present embodiment, the ion exchange membrane can be more easily assembled into the apparatus.

Moreover, the ion exchanger 21, the ion exchange unit 20, the ion exchange apparatus 18, and the water treatment apparatus 10 which can be assembled more easily can be obtained by using such an ion exchange membrane.

As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible.

For example, the water treatment device may include at least an ion exchange device.

According to the present invention, it is possible to obtain an ion exchange membrane, an ion exchanger, an ion exchange unit, an ion exchange device, and a water treatment device using the ion exchange device, which can be assembled more easily.

Claims

An ion exchange membrane characterized by having an ion exchange function and being hardly swellable in water.
The ion exchange membrane according to claim 1, wherein the ion exchange membrane is formed by laminating fibers having an ion exchange group at least on the surface in a non-woven fabric state.
The ion exchange membrane according to claim 2, wherein the ion exchange membrane has flexibility.
The ion exchange membrane according to any one of claims 1 to 3 is disposed at both ends in one direction of the ion exchange portion so as to sandwich an ion exchange portion having an ion exchange function. Ion exchanger.
An ion exchange unit, wherein an anode and a cathode are disposed on both sides of the ion exchanger according to claim 4 so as to sandwich the ion exchanger.
The ion exchange unit according to claim 5, wherein at least one of the anode and the cathode is formed of a conductive fiber.
An ion exchange apparatus comprising at least one ion exchange unit according to claim 5.
A water treatment device comprising the ion exchange device according to claim 7.