JP5573259B2 - Liquid filtration filter and liquid filtration method - Google Patents

Description

  The present invention relates to a liquid filtration filter for adsorbing and separating a small amount of metal, fine particles, etc. contained in a liquid to be treated in the treatment of a liquid such as water, an aqueous solution, an organic solvent, and the like. The present invention relates to the liquid filtration method used.

  The demand for high-purity ultrapure water used in semiconductor manufacturing processes is becoming stricter year by year. According to ITRS 2005, a roadmap for reducing the metal ion concentration in ultrapure water to 0.5 ng / L or less was presented in 2008. However, each semiconductor manufacturer has decided to use ultrapure water with a lower metal concentration. Looking for. Water treatment manufacturers have reduced the metal ion concentration ahead of schedule, and some of the latest ultrapure water production facilities can produce ultrapure water with most metals reduced to 0.5 ng / L or less. .

  As a method of reducing the metal concentration in ultrapure water, there is a method of installing an ion exchange filter immediately before a use point.

  As a conventional ion exchange filter, there is a pleat type flat membrane such as a nonwoven fabric or a porous membrane (for example, Patent Document 1).

  As an ion exchange membrane, an ion exchange resin is dissolved or dispersed in a solvent to form a cast stock solution. The cast stock solution is cast on a base film, dried, and then peeled off from the base film. Are known (for example, Patent Documents 2 and 3). Patent Document 3 describes a porous ion exchange membrane manufactured by using a phase separation method.

  An electrospinning method (electrostatic spinning method) is known as a method for producing ultrafine nanofibers having a fiber diameter of nanometer order (Patent Documents 4 and 5 below). In this electrospinning method, an electric field is formed between a nozzle and a target, and spinning is performed by discharging a liquid raw material from the nozzle in the form of fine fibers. The fine fibers are accumulated on the target to form a fibrous body. In addition, this inventor has proposed the ion exchange filter using the ultrafine fiber (nanofiber) which has an ion exchange group (patent document 6).

JP 9-206509 A JP 2000-327809 JP 2006-193709 A JP2007-92237 JP 2006-144138 A JP2009-219952

  In the pleated ion exchange filter, the flow tends to be biased in the folded portion of the pleat, and a sufficient removal rate cannot be obtained in an extremely low concentration region such as the above-described ultrapure water. Further, since the film thickness is thin, breakthrough is quick and the life is short. Further, in order to improve the ion removal rate, if the film thickness is increased or the pores of the film are reduced, the water permeability is sacrificed.

  An ion exchange filter using nanofibers having ion exchange groups is excellent in ion removal performance, but has a large pressure loss.

  The present invention provides a liquid filtration filter and a liquid filtration method that have the ability to remove ultra-low concentration ions, and have high water permeability and long life, satisfying the demand for high purity of ultrapure water in the semiconductor industry and the like. It is intended.

The liquid filtration filter of the present invention (Claim 1) accommodates an ion exchange filter in which a laminated sheet of an ion exchange sheet and a flow path material sheet is spirally wound around the outer periphery of the core material, and the core material. A filter for filtering a liquid to be treated from one end surface to the other end surface of the ion exchange filter , wherein the ion exchange sheet includes ion exchange fiber cloths made of ion exchange fibers. An ion-exchange cast membrane is interposed between the two.

Liquid filtration filter according to claim 2 is characterized in that Oite to claim 1, a plurality of the ion exchange filter into the housing is arranged to be passed through in series.

According to a third aspect of the present invention, the liquid filtration filter according to the second aspect is characterized in that a porous plate and / or a separation membrane is provided on at least one of the upstream side and the downstream side of the ion exchange filter.

The liquid filtration method of the present invention (Claim 4 ) is to pass the liquid to be treated through the liquid filtration filter according to any one of Claims 1 to 3 .

  The ion exchange filter used in the liquid filtration filter of the present invention is obtained by winding a laminated sheet of a flow path material sheet and an ion exchange sheet around the outer periphery of a core material in a spiral shape. The liquid to be treated is passed from the end face toward the other end face. In this way, the laminated sheet has the flow path material sheet, and the liquid to be treated flows spirally from the one end surface to the other end surface in the ion exchange filter, so that the pressure loss is small. In addition, since the entire ion exchange sheet from one end surface to the other end surface becomes an adsorption band and the adsorption band length is large, the time until breakthrough of ions becomes long and the life of ion exchange becomes long.

  When at least a part of the ion exchange sheet is composed of an ion exchange fiber cloth, the contact area between the liquid to be treated and the ion exchange fiber cloth is large, so that the ion exchange sheet is sufficiently deionized.

  When at least a part of the ion exchange sheet is formed of an ion exchange cast membrane, the ion exchange capacity is increased.

  When the ion exchange sheet is composed of an ion exchange fiber cloth and an ion exchange cast film in contact with the ion exchange fiber cloth, ions adsorbed by the ion exchange fiber cloth can be moved to the ion exchange cast film and held.

  By providing a porous plate or a porous film on the upstream side or downstream side of the ion exchange filter, liquid drift and short path are prevented or suppressed.

It is a block diagram which shows the ion exchange filter which concerns on embodiment. It is a block diagram of the filter for liquid filtration which concerns on embodiment. It is a block diagram of the filter for liquid filtration which concerns on another embodiment. It is a block diagram of the filter for liquid filtration which concerns on different embodiment.

  Hereinafter, embodiments will be described with reference to the drawings. In the following description, water is passed as the liquid to be treated, but a liquid other than water may be used.

  FIG. 1A is a cross-sectional view showing a method of manufacturing an ion exchange filter according to an embodiment, FIG. 1B is a cross-sectional view of a laminated sheet, and FIG. 1C is a perspective view of the ion exchange filter.

  The ion exchange filter 1 includes a core material 2 and a laminated sheet 3 wound around the outer periphery of the core material 2. The laminated sheet 3 is obtained by laminating a flow path material sheet 4 and an ion exchange sheet 5. The core material 2 may be a solid rod shape, but may be a hollow pipe shape for weight reduction. However, the end of the pipe is closed so that water does not flow in the longitudinal direction in the pipe. Moreover, no hole is provided in the outer peripheral surface of the pipe. The diameter of the core material is preferably about 1 to 50 mm, particularly about 3 to 20 mm. The core material is preferably a polyolefin resin such as polyethylene or polypropylene, or a fluororesin such as polytetrafluoroethylene, but is not limited thereto.

  The flow path material sheet 4 is preferably a non-woven fabric, woven fabric, grid-like net or the like made of polyolefin (polyethylene, polypropylene), polyester, polysulfone or the like. The thickness of the flow path material sheet is preferably 0.1 mm to 5 mm, particularly about 0.5 to 2 mm, and the pore diameter is preferably about 100 μm or more (opening: 50% to 90%).

  The ion exchange sheet 5 is made of a woven or nonwoven fabric of ion exchange fibers, an ion exchange cast membrane, or the like, but preferably has a three-layer structure in which an ion exchange cast membrane 7 is interposed between the nonwoven fabrics 6 and 6 of ion exchange fibers. Is. A suitable example of the ion exchange sheet 5 will be described in detail later.

  The laminated sheet 3 is wound around the outer periphery of the core material 2 in a spiral shape (spiral shape) to form an ion exchange filter 1. The number of layers by the winding (when the core material 2 is rotated, the total number of rotations) is preferably about 10 to 200, particularly about 30 to 100. When the laminated sheet 3 is wound, a roll-shaped wound body is obtained. The water to be treated is passed from one end surface of the ion exchange filter 1 made of this roll-shaped winding body toward the other end surface.

  FIG. 2 is a plan view showing an example of a liquid filtration filter incorporating the ion exchange filter 1 of FIG.

  This filter 10 for liquid filtration arranges the several ion exchange filter 1 coaxially in the cylindrical housing 13 which has the inflow port 11 of the to-be-processed water, and the outflow port 12 of filtrate water. . Supports 14 are disposed on the upstream side and the downstream side of the ion exchange filter 1. The support 14 desirably has a function of dispersing water flowing out from the upstream ion exchange filter 1 and allowing the water to flow into the downstream ion exchange filter 1. The support 14 may be composed of a separation membrane (microfiltration membrane, ultrafiltration membrane, etc.) and / or a porous disk, and is configured as a support 21 in FIG. 4 described later. May be.

  As shown in FIG. 3, the liquid filtration filter 10 is disposed in the pressure vessel 15, and water to be treated is supplied into the pressure vessel 15 from the supply port 16 and flows into the liquid filtration filter 10. Good. In this case, the end plate on the inlet side of the housing 13 may be omitted.

  FIG. 4 (a) is a sectional view of a liquid filtration filter 20 in which a plurality of (in this case, two) ion exchange filters 1 are disposed coaxially with a support 21 in a cylindrical housing 13. (B) is an exploded sectional view of the support 21, and (c) is an exploded plan view of the support 21. In FIG. 4, two ion exchange filters 1 are provided, but three or more may be used, and usually about 1 to 5 are suitable.

  The support 21 has a large number of holes 22a, a perforated plate 22 having an O-ring 22b attached to the outer peripheral surface, a mesh 23 that overlaps the perforated plate 22, a microfiltration membrane 24 that overlaps the mesh 23, An O-ring 25 that overlaps the filtration membrane 24 is included. The microfiltration membrane 24 preferably has a pore diameter of 0.02 to 0.45 μm. The position of the support 21 is fixed by the O-rings 22b and 25, and water leakage from between the inner peripheral surface of the housing 13 and the outer peripheral surface of the support 21 is prevented. Fine particles are removed by the microfiltration membrane 24, and the flow rate of water passing through the ion exchange filter 1 on the upstream side of the support 21 is controlled to prevent or suppress short paths and drift.

  Since a plurality of ion exchange filters 1 are installed in series in the housing 13, one ion exchange filter 1 has a portion that is easy to flow and a portion that is difficult to flow. Since water merges before flowing into the ion exchange filter on the side, the short path / uneven flow does not reach the entire length of the liquid filtration filter.

  Moreover, by installing the support body 21 before and after the ion exchange filter 1, water can be mixed and rectified, and the flow rate of water can be controlled by the resistance of water flow through the support body 21. Thereby, a short path and drift can be further reduced.

  Examples of the material of the porous plate 22 include polyolefin (polyethylene, polypropylene), polytetrafluoroethylene, and the like.

  As the mesh 23, polyolefin (polyethylene, polypropylene), polyester or the like is suitable, and the thickness is 0.05 mm to 3 mm, particularly 0.1 to 2 mm, and the pore diameter is 10 μm or more (opening: 30% to 90%). It is desirable to be in the range.

  Examples of the material for the microfiltration membrane 24 include polyvinylidene fluoride, polytetrafluoroethylene, polysulfone, polyamide, and cellulose. The thickness of the microfiltration membrane 24 is 0.05 mm to 0.5 mm, preferably 0.1 to 0.3 mm, and the pore diameter is 0.02 to 1 μm, particularly 0.02 to 0.45 μm.

The support 21 may have a woven or non-woven fabric of ion exchange fibers. The material of this ion exchange fiber can use the same thing as the below-mentioned ion exchange fiber sheet. As this woven fabric or non-woven fabric, the fiber diameter obtained by electrospinning and melt spinning a polymer solution is 0.01 to 5 μm, the thickness is 0.01 to 1 mm, and the pores are 0.02 to 10 μm (by the air flow method). Measurement), those having an ion exchange capacity of 0.05 to ³ meq / g, 0.03 to 1.5 meq / cm ³ are suitable. As this ion exchange fiber, a functional group that removes ions having a sign opposite to that of the ion exchange group of the ion exchange filter may be used. With this configuration, the ion removal effect may be improved.

  In order to carry the ion exchange fiber, a nonwoven fabric made of polyolefin, polystyrene, polysulfone, polyester, polyvinylidene fluoride, or the like may be used.

  You may introduce | transduce into the ion exchange fiber of the several ion exchange filter 1 and 1 the functional group which removes a different function, for example, the ion from which a code | symbol differs. In this case, the ion removal performance may be improved and the filter life may be extended, as in the case where a mixed bed resin tower is used.

[Detailed description of the ion exchange sheet and the ion exchange filter around which the ion exchange sheet is wound]
As described above, a cast membrane, a woven fabric or a non-woven fabric of ion exchange fibers, or the like is used for the ion exchange sheet. These will be described in detail below.

[1] Kind of ion exchange sheet (1) Ion exchange fiber sheet As the ion exchange fiber, a material obtained by spinning the following materials (a) to (d) by an electrospinning method or a melt spinning method is preferable. The ion exchange fiber sheet is a nonwoven fabric or a woven fabric using these alone or in combination.

(A) Perfluorocarbon sulfonic acid polymer (Nafion (registered trademark), Fumion (manufactured by FuMA-Tech)) as a charged polymer fiber
(B) An ion exchange group chemically attached to a base material made of uncharged polymer fiber (c) Perfluorocarbon sulfonic acid polymer (Nafion (registered trademark), Fumion) as a charged polymer fiber Integrated with skeletal material by supporting on skeletal material (d) Integrated with skeletal material with ion exchange group chemically added to base material made of uncharged polymer fiber High mechanical strength The above (c) or (d) is preferred to obtain

The thickness of the ion exchange fiber sheet is preferably about 0.01 to 0.5 mm (10 to 500 μm), and the pore diameter is preferably about 0.1 to 10 μm (measured by air flow method, the same applies hereinafter), The ion exchange capacity is preferably about 0.05 to 2 meq / g, about 0.03 to 1.5 meq / cm ³ . After producing a fiber sheet by spinning a fiber having no ion exchange group, an ion exchange group can be imparted to the fiber sheet by a graft polymerization method or other chemical reaction methods (electrophilic substitution reaction, addition reaction, etc.).

  Examples of the uncharged polymer include polyolefin, polystyrene, polysulfone, polyester, and polyvinylidene fluoride.

  As the ion exchange group, various cation exchange groups or anion exchange groups can be used. For example, as the cation exchange group, a strong acid cation exchange group such as a sulfone group, a neutral acid cation exchange group such as a phosphate group, a weak acid cation exchange group such as a carboxyl group, and an anion exchange group include primary to first-order cation exchange groups. A weakly basic anion exchange group such as a tertiary amino group and a strongly basic anion exchange group such as a quaternary ammonium group can be used, or an ion exchanger having both the cation exchange group and the anion exchange group Can also be used.

  Examples of the skeletal material include nonwoven fabrics and woven fabrics made of polyolefin, polystyrene, polysulfone, polyester, polyvinylidene fluoride, and the like.

  As the ion exchange fiber, an extremely thin fiber having an equivalent diameter of 1 to 1000 nm, particularly about 10 to 700 nm is preferable. Here, “equivalent diameter” is calculated by (equivalent diameter) = 4 × (cross-sectional area) / (peripheral length of cross-section) from the cross-sectional area of one fiber (fiber) and the outer peripheral length of the cross-sectional area. Value.

  The length of the ion exchange fiber is preferably 1 μm or more. When produced by electrospinning, the length can be several centimeters and can be continuously spun, so that the length can be further increased several times.

  When spinning an ion exchange fiber, it may be difficult to spin the charged polymer alone, and even if it can be spun, the bulk (bulk) becomes higher due to the charge repulsion between the fibers, and the fit becomes worse. (That is, the bulk density is low) and may not be suitable for filtering. On the other hand, as the non-electrolytic polymer, it is possible to select a polymer that can be easily spun by itself, and since there is no repulsion between fibers after spinning, it is easy to filter. Therefore, by mixing and spinning an electrolyte polymer and a non-electrolyte polymer, fibers having excellent characteristics of both can be obtained. In electrospinning, the spinnability during spinning is also improved.

(2) Ion Exchange Cast Membrane As the ion exchange cast membrane, a porous membrane produced by a phase separation method using one or more of the following (e) to (h) is suitable.

(E) A film-like product obtained by applying a perfluorocarbon sulfonic acid polymer (Nafion (registered trademark), Fumion) on a substrate such as glass and then removing the substrate. (F) Ions on a substrate made of an uncharged polymer (G) Perfluorocarbon sulfonic acid polymer (Nafion (registered trademark), Fumion) is used as a skeletal material. Coated and integrated with skeletal material (h) Coated with base material made of uncharged polymer and chemically exchanged ion exchange groups applied to skeletal material and integrated with skeletal material High machinery In order to obtain the desired strength, the method (g) or (h) is preferred.

The thickness of the cast membrane is preferably about 0.01 to 0.5 mm (10 to 500 μm), the pore diameter is preferably 1 μm or less, and the ion exchange capacity is 0.2 to 4 meq / g, 0.1 About 3.5 meq / cm ³ is preferable. After forming a cast film by forming an uncharged polymer film, an ion exchange group can be added to the cast film by graft polymerization or other chemical reaction methods (electrophilic substitution reaction, addition reaction, etc.). .

  As the non-chargeable polymer, ion exchange group, and skeleton material, the same ones as described above can be used.

[2] Ion removal performance By using the fiber surface of the ion exchange fiber sheet as an ion exchange field, the contact efficiency of the fluid around the fiber is improved, so that the ion adsorption rate is increased. However, only the ion exchange fiber sheet has a limit in the retention capacity of the adsorbed ions.

  On the other hand, in the case of an ion exchange cast membrane, functional groups for removing ions can be held at a high density, and an ion removal capacity can be ensured. Therefore, by bringing the ion-exchange fiber sheet into contact with the ion-exchange fiber sheet, the ions adsorbed on the ion-exchange fiber can be moved to the ion-exchange cast film and held at a high density. In addition, when water is passed from one end surface to the other end surface of an ion exchange filter in which the ion exchange sheet is wound in a roll shape, the length in the winding axis direction of the ion exchange filter becomes the length of the adsorption band. The adsorption band length increases. This increases the breakthrough time and the filter life.

[3] Suppression of pressure loss In the case of an ion exchange fiber sheet, the ion exchange capacity can be increased by thinning the ion exchange fiber to increase the specific surface area. On the other hand, the ion exchange cast membrane is denser than the ion exchange fiber sheet, and the permeation resistance is high.

  Accordingly, the ion exchange sheet obtained by laminating the ion exchange fiber sheet and the ion exchange cast membrane and the flow path material sheet are laminated, and water is passed from the one end surface to the other end surface with respect to the roll ion exchange filter. By doing so, that is, by passing water parallel to the core material, the pressure loss is reduced.

  In addition, the filter for liquid filtration and the liquid filtration method of the present invention can be suitably used to remove ionic substances, colloids, and particles dissolved in water. Water, lake water, industrial water, biological treatment, coagulation treatment, precipitation treatment, pressurized flotation treatment, filtration, activated carbon treatment, ion exchange resin treatment, microfiltration, ultrafiltration, reverse osmosis treatment, electric regenerative deionization treatment Water subjected to any treatment such as decarboxylation treatment or UV treatment is exemplified.

  When the ion concentration of the water to be treated is high, the filter life is shortened and the frequency of replacement is increased. Therefore, it is more efficient to perform pretreatment such as ion exchange resin treatment, reverse osmosis treatment, and electric regenerative deionization treatment. become. The filter of the present invention is effective when further removing ions from water having a low ion concentration or water from which ions have been removed to some extent. For example, it may be used for further removing ions from ultrapure water having a specific resistance of 1 MΩ · cm or more.

[Examples 1 to 6, Comparative Examples 1 and 2] (Filter for liquid filtration provided with only one stage of ion exchange filter)
In Examples 1 to 6 and Comparative Examples 1 and 2 below, an ion exchange filter wound in a spiral shape as shown in FIGS. 1A and 1B is manufactured. In Examples 1 to 6, the ion exchange filter is parallel to the core material. Water was passed in the direction, and in Comparative Examples 1 and 2, water was passed in the spiral direction.

  The ion exchange sheet used for the ion exchange filter is the ion exchange fiber sheets F1 and F2 shown in Table 1 or the ion exchange cast membrane M1 or M2. The used flow path material sheet is a polyester lattice net S1 or S2 shown in Table 2.

  The core material 2 used in Examples 1 to 6 is made of a polypropylene pipe having an outer diameter of 10 mm and an inner diameter of 6 mm, and both end surfaces are closed. In Comparative Examples 1 and 2, a large number of small holes having a diameter of 2 mm were formed on the peripheral surface of the pipe with a hole interval of 2 mm.

  In each of Examples 1 to 6 and Comparative Examples 1 and 2, the ion exchange fiber sheet, the ion exchange cast membrane, and the flow path material sheet shown in Tables 1 and 2 are stacked as specified in Table 3 so that the outer diameter becomes 80 mm. The core was wound into a roll and cut to a length of 200 mm. In Comparative Examples 1 and 2, both the cut end faces of the roll sheet were sealed with an adhesive so that water did not escape.

3) Water flow test conditions The filter was set in a filter cartridge, and pure water containing 1 ng / L of Na ions was passed at 20 L / min. As described above, in Examples 1 to 6, water was passed from one end surface to the other end surface in a direction parallel to the core material. In Comparative Examples 1 and 2, water was passed in a spiral direction from the outer peripheral surface of the roll-shaped wound body, and water was passed by a pressure permeation method in which treated water was taken out from the core material. The results are shown in Table 3.

4) Results and Discussion Regarding Comparative Example 1 and Examples 1 and 2 using only ion exchange fibers, compared with Comparative Example 1 which is a pressure transmission system, in Examples 1 and 2, the pressure loss is kept low, Although a high ion removal rate could be obtained, the ion removal rate gradually decreased.
Since the ion exchange fiber has a high adsorption rate, a high ion removal rate was obtained in the initial stage. However, the ion exchange capacity of the ion exchange fiber is small, and thus the ion removal rate seems to have decreased over time.
In Example 2, since the spacer is thinner than Example 1, the number of windings is increased and the pressure loss is increased, but the contact area is increased and the ion removal rate is increased.
In Comparative Example 2 and Examples 3 and 4 using only the ion exchange membrane, in Examples 3 and 4, the pressure loss is kept low while the pressure loss is kept low compared to Comparative Example 2 in which water cannot be passed due to the pressure permeation method. However, the ion removal rate was lower than that of Examples 1 and 2.
Since the ion exchange membrane has a low adsorption rate, a high ion removal rate could not be obtained. However, since the ion exchange membrane has a large ion exchange capacity, it seems that the performance could be maintained for a long time.
In Example 3, since the ion exchange membrane was thinner than in Example 4, the ratio of spacers was increased, the pressure loss was slightly reduced, the contact area was increased, and the ion removal rate was increased.
Examples 5 and 6 in which ion exchange fibers and ion exchange membranes are laminated are compared with Examples 1 and 2 using only ion exchange fibers and Examples 3 and 4 using only ion exchange membranes. Thus, it was possible to obtain a higher ion removal rate while keeping the pressure loss low, and to maintain the performance for a long time.
It seems to be a synergistic effect of the high adsorption rate of the ion exchange fiber and the large ion exchange capacity of the ion exchange membrane.
Further, the ion removal rate of Example 6 was higher than that of Example 5. This seems to be because the contact area is larger in Example 6 in which ion exchange fibers are laminated on both sides of the ion exchange membrane than in Example 5 in which ion exchange fibers are laminated on one side of the ion exchange membrane.

[Examples 7 to 9, Comparative 1 to 3] (Contrast between the case where the ion exchange filter is made in a single stage and the case where the ion exchange filter is made in multiple stages)
An ion exchange filter was manufactured using the following sheet A, flow path material B, and core material C, accommodated in a cylindrical container, and allowed to pass water.

<Material>
・ Sheet A
A solution containing 14% by weight of Nafion, 8% by weight of PVDF (polyvinylidene fluoride) and 78% by weight of DMAc (dimethylacetamide) as a solution containing a non-electrolyte polymer and an electrolyte polymer is placed in a syringe with a syringe diameter of 30G. A cation exchange fiber is spun by applying a negative 35 kV voltage (4 kV / cm potential gradient) to the target side for collecting the fiber, and the cation exchange fiber is laminated to form a cation having a thickness of 50 μm composed of a fiber having a diameter of 200 nm. A non-woven fabric of exchange fibers was produced.
・ Channel material B
A polyester mesh, a thickness of 0.7 mm, a fiber thickness of 0.35 mm, and an opening of 70% were used.
・ Core C
Made of polypropylene, 5mm in diameter

<Comparison 1>
An ion exchange filter having an adsorbing band length of 5 cm was manufactured by aligning the width to 5 cm and winding the sheet A around the core material C together with the channel material B. This was press-fitted into the center of a cylindrical container having an inner diameter of 2 cm and a length of 9 cm.

<Comparison 2>
An ion exchange filter having an adsorbing band length of 5 cm was manufactured by winding only the sheet A around the core material C and having a width of 5 cm, and this was press-fitted into the center of a cylindrical container having an inner diameter of 2 cm and a length of 9 cm.

<Example 7>
The sheet A was wound around the core material C together with the flow path material B with a width of 2.5 cm, and two ion exchange filters having an adsorption band length of 2.5 cm were produced. These were press-fitted into a cylindrical container having an inner diameter of 2 cm and a length of 9 cm. A space of 1 cm was left between the ion exchange filters.

<Example 8>
Four ion exchange filters having an adsorption band length of 1.25 cm were prepared by aligning the width to 1.25 cm and winding the sheet A around the core material C together with the flow path material B. These were press-fitted into a cylindrical container having an inner diameter of 2 cm and a length of 9 cm. A space of 1 cm was left between the ion exchange filters.

<Example 9>
Four ion exchange filters having an adsorption band length of 1.25 cm were prepared by aligning the width to 1.25 cm and winding the sheet A around the core material C together with the flow path material B. These were press-fitted into a cylindrical container having an inner diameter of 2 cm and a length of 9 cm. A space of 1 cm was left between the ion exchange filters.

  In Example 9, polypropylene having a thickness of 180 μm is used as the microfiltration membrane 24 of the support 21 shown in FIGS. 4B and 4C between the ion exchange filters and on the outer end surfaces of the rolls at both ends. A support using a membrane formed by mixing a quaternary ammonium polysulfone and polyvinylidene fluoride in a weight ratio of 1: 1 on a non-woven fabric and electrospinning to form a non-woven fabric having a thickness of 5 μm was inserted. The O-ring 25 is made of P16, silicon rubber, the mesh 23 is a polyolefin mesh (thickness 0.55 mm, fiber thickness 0.28 mm, opening 80%), and the porous plate 22 is made of polytetrafluoroethylene porous. The plate (2 mmφ × 21 hole, thickness 4 mm) and the O-ring 22 b are made of P16, silicon rubber.

<Evaluation test>
Ultrapure water to which 1 ppb Na was added as NaCl was treated water, which was passed at a flow rate of 0.3 L / min, and pressure loss and treated water Na concentration were measured. The Na removal rate was calculated by the following formula. The results are shown in Table 4.

    Na removal rate [%] = (1- [treated water Na concentration] / [treated water Na concentration]) × 100

<Discussion>
From the comparison between Comparative Example 1 and Examples 7 and 8, even though the total length of the filter is the same, short paths and drift are reduced by disposing the filter, Na removal rate is increased, fine particles are reduced, and the quality of the treated water It is recognized that is improved.

  In contrast 2, since the pressure loss was 300 kPa or more, water could not be passed.

  As shown in Example 9, by adding a perforated plate and a microfiltration membrane, the pressure loss increased as compared with Example 8, but the quality of treated water, particularly the particulate removal performance, is significantly improved.

DESCRIPTION OF SYMBOLS 1 Ion exchange filter 2 Core material 3 Laminated sheet 4 Channel material sheet 5 Ion exchange sheet 6 Non-woven fabric of ion exchange fiber 7 Ion exchange cast membrane 21 Support body 22 Perforated plate 23 Mesh 24 Precision filtration membrane 25 O-ring

Claims (4)

An ion exchange filter in which a laminated sheet of an ion exchange sheet and a flow path material sheet is spirally wound around the outer periphery of a core material, and a housing that contains the core material, and the other from one end surface of the ion exchange filter A liquid filtration filter through which a liquid to be treated is passed toward an end surface ;
A filter for liquid filtration, wherein the ion exchange sheet is obtained by interposing an ion exchange cast membrane between ion exchange fiber cloths made of ion exchange fibers. Oite to claim 1, liquid filtration filter having a plurality of the ion exchange filter in the housing is characterized in that it is arranged to be passed through in series. 3. The liquid filtration filter according to claim 2 , wherein a porous plate and / or a separation membrane is provided on at least one of the upstream side and the downstream side of the ion exchange filter. Liquid filtration method for liquid permeability of the liquid to be treated in the liquid filtration filter according to claim 1 to any one of the three.

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