WO2021085601A1

WO2021085601A1 - Filter for liquid filtration

Info

Publication number: WO2021085601A1
Application number: PCT/JP2020/040811
Authority: WO
Inventors: 宮本竜馬; 水野耀介; 花田茂久; 山村剛平
Original assignee: 東レ株式会社
Priority date: 2019-10-31
Filing date: 2020-10-30
Publication date: 2021-05-06
Also published as: JP7021719B2; JPWO2021085601A1; CN114630702A

Abstract

The present invention is a filter for liquid filtration, said filter being provided with a perforated core material and a woven fabric that is wound around the outer periphery of the perforated core material. This filter for liquid filtration satisfies conditions such that: a warp of the woven fabric contains a multifilament that contains from 7 to 700 single yarns having a diameter from 1 μm to 100 μm; a portion where three or more single yarns contained in a warp are stacked in the thickness direction is present in a cross-section of the warp, said cross-section being perpendicular to the longitudinal direction; the aspect ratio of a cross-section of a warp is from 1.5 to 10; and the like.

Description

Liquid filtration filter

Regarding filters that can adsorb inorganic ion components dissolved in liquid.

As a means for adsorbing and removing a component dissolved in a liquid, a filter in which a woven fabric made of a fibrous adsorbent on which a metal hydroxide capable of adsorbing the component is immobilized is laminated has been proposed.

The larger the amount of the metal hydroxide immobilized on the fiber, the larger the amount of the component dissolved in the liquid that can be removed, which is preferable. In order to increase the amount of metal hydroxide supported, a method of supporting it not only on the surface of the fiber base material but also on the inside has been proposed.

In Patent Document 1, a cation exchange group is graft-polymerized on an organic polymer fiber to form a polymer compound layer having a cation exchange group on the outer periphery of the organic polymer fiber, and the polymer compound layer having the cation exchange group is formed. Disclosed is a woven fabric or a non-woven fabric made of anion-adsorbing fibers carrying a metal hydroxide.

Further, Patent Document 2 discloses a woven fabric made of deodorant fibers in which a resin layer containing a metal oxide is formed around the base fibers.

Further, Patent Document 3 describes a fibrous adsorbent having a resin layer containing metal particles capable of removing arsenic contained in groundwater, phosphorus contained in wastewater, fluorine, boron contained in seawater, and the like. Is a filter made of woven fabric or knitted fabric and surrounded by a perforated core material, which defines and discloses variations in fiber diameter, porosity, and porosity.

Japanese Patent Application Laid-Open No. 2018-158327 Japanese Patent Application Laid-Open No. 2017-666568 WO / 2019/065092

An object of the present invention is to provide a fibrous adsorbent that has a large amount of metal oxide capable of adsorbing components dissolved in water and that the supported metal oxide can effectively contribute to adsorption. It is an object of the present invention to provide a filter which can obtain a high removal rate and a long filtration life by adopting a woven structure.

In order to achieve the above object, the filter of the present invention
A liquid filtration filter including a perforated core material and a woven fabric surrounded by the outer circumference of the perforated core material.
A filter in which the woven fabric satisfies the following conditions (a) to (d).
(A) The warp and the weft include a multifilament containing 7 to 700 single yarns having a diameter of 1 μm to 100 μm, and the single yarns contained in the warp and the weft are thick in each cross section perpendicular to the longitudinal direction of the warp and the weft. There are three or more laminated parts in the direction, and the aspect ratio of the cross section of the warp and weft is 1.5 to 10.
(B) The total cover factor of the warp and weft is 1200 or more and 2200 or less.
(C) At least one of the warp or weft contains, as the single yarn, a fibrous adsorbent having a layer of a polymeric compound having an ion exchange group; metal particles supported on at least the surface of the layer (c). d) The amount of the metal particles supported is 5 to 60% by mass with respect to the mass of the woven fabric.

When the woven fabric is viewed from the upper surface or the lower surface, the gaps between the fiber bundles constituting the woven or knitted fabric are not formed, the gaps between the single yarns are secured, and the raw water is prioritized on the surface of each single yarn. Because the contact area with the raw water is large and the adsorption rate is high, the removal rate is high as a result, and the metal oxide supported inside the single yarn can also effectively contribute to the adsorption. In addition, the filtration life is extended.

In addition, the flow of raw water between the single yarns, not between the fiber bundles, causes an appropriate water flow resistance in the adsorption layer when the raw water is wound around the effective core material and used as a filter, and the effective core of the filter. Since the flow rate is less likely to be uneven in the axial direction of the material and the adsorbent in the filter is used uniformly, the filtration life is improved.

It is a schematic diagram of a filter. It is a top view of a woven fabric. It is sectional drawing of the woven fabric. It is sectional drawing of the deformed fibrous adsorbent which is a single yarn. It is sectional drawing of the fibrous adsorbent which is a single yarn. It is sectional drawing of the water purifier which has a filter and a hollow fiber type separation membrane.

1. 1. Filter Hereinafter, embodiments of the liquid filtration filter of the present invention will be described. The filter in the present embodiment includes a perforated core material and a woven fabric wound around the perforated core material.

The perforated core material (hereinafter, simply referred to as "core material") is a hollow cylinder, at least one end thereof is open, and a plurality of holes are provided on the side surface thereof. As the material of the core material, for example, a synthetic resin is applied, and specifically, polyolefins such as polyethylene and polypropylene, or fluororesins such as PTFE and PFA are suitable.

The diameter (outer diameter) of the core material is preferably 5 mm or more or 8 mm or more, and preferably 50 mm or less or 30 mm or less. The length of the core material is not particularly limited, but is, for example, 80 mm or more and 500 mm or less.

The woven fabric that is wrapped is called a wrapping body. It is preferable that the end in the winding direction of the woven fabric is fixed to the outer peripheral surface of the surrounding body by welding, adhesion, or the like.

The filter has a circular plate or the like on the end face, or has an end face for the purpose of preventing a short path of raw water from the end face of the winding body (the end face in the height direction of the surrounding body if the surrounding body is columnar). It is preferably sealed with an adhesive. The adhesive is not particularly limited, and examples thereof include an epoxy resin adhesive, a silicone resin adhesive, and a urethane resin adhesive.

The filter will be explained more specifically. The filter 16 of FIG. 1 has a core material 13 and a woven fabric 11. The core material 13 is a hollow member having an open top and a closed bottom. A plurality of holes 14 are provided on the side surface of the core material 13. The wrapping body 10 is formed by wrapping the woven fabric 11 around the core material 13.

In the form of FIG. 1, the filter 16 is housed in the casing 17. The casing 17 is configured so that the supply water enters the inside of the core material 13 through the opening at the upper part of the core material 13 by providing a water supply port (not shown) which is an opening at the upper portion thereof. There is. An intake port (not shown), which is an opening, is also provided at the bottom of the casing 17, so that permeated water flows out of the filter from the water intake port.

Although the flow of water is drawn so as to go from the inside to the outside of the surrounding body 10 in FIG. 1, the flow of water may be reversed. That is, it is also possible to supply water to the side surface of the winding body and collect the permeated water from the core material. In this case, for example, as the casing 17 in FIG. 1, a supply port capable of supplying water between the surrounding body 10 and the inner wall of the casing 17 is provided at the lower part, and the permeated water is permeated through the opening at the upper part of the core material 13. A casing may be used that has an intake port at the top so that the water can be taken out.

2. Wrap body A wrapping body is a woven fabric that is wrapped around a core material.

The outer shape of the winding body corresponds to the outer shape of the core material in many cases, but it can be adjusted by the shape of the woven fabric, the number of times of winding, etc. As the outer shape of the surrounding body, various shapes such as a cylinder; a prism such as a triangular prism or a quadrangular prism; a cone; a pyramid such as a triangular pyramid or a quadrangular pyramid; or a sphere or an elliptical sphere can be adopted.

3. 3. Woven fabrics Woven fabrics are fabrics having warp threads and weft threads that intersect each other, and examples thereof include three original structures such as plain weave, twill weave, and satin weave, and their modified structures. Examples of the changing structure include the ridge weave and the satin weave, which are the changing structures of the plain weave, and the twill twill, the French twill weave, the bent twill weave, the torn twill weave, and the steep twill weave. In addition to the gentle twill weave, irregular twill weave, layered satin weave, wide twill weave, mikage satin weave, blurred satin weave, and day and night satin weave are examples. In addition, there are vertical pile weaves such as vertical velvet, towels and velor, entwined weaves and imitation weaves. The woven fabric having these weaving structures can be woven by a normal method using a normal loom such as a rapier loom or an air jet loom. In terms of removal rate and filtration life, a twill weave or a twill weave with few intersections is preferable, and a satin weave or a satin weave change structure is more preferable.

The woven fabric has multifilaments as warp and weft. The multifilament contains 7 to 700 single yarns with a diameter of 1 μm to 100 μm. In each cross section perpendicular to the longitudinal direction of the warp and the weft, there is a place where three or more single yarns contained in the warp and the weft are laminated in the thickness direction of the woven fabric (vertical direction in FIG. 3), and the warp is The aspect ratio of the cross section of the weft is 1.5 to 10, preferably 1.7 to 5, and more preferably 1.7 to 4.

A more specific explanation will be given with reference to FIGS. 2 and 3. The woven fabric 11 of FIG. 2 has a warp 31 and a weft 32, and each of the warp 31 and the weft 32 is a multifilament. However, the warp and weft in the woven fabric 11 do not have to be all multifilaments, and some of them may be monofilaments. Further, the warp 31 or the weft 32 which is a multifilament does not have to have the same structure and composition, and the woven fabric 11 may contain a plurality of types of multifilaments having different structures or compositions. Further, the single yarns constituting one multifilament do not have to have the same structure and composition, and the multifilament may include a plurality of single yarns having different structures or compositions.

The shapes in the AA cross section perpendicular to the warp 31 and the BB cross section perpendicular to the weft 32 will be described. Since the description of both cross sections is common, FIG. 3 shows the AA cross section, and the illustration and description of the BB cross section are omitted. The warp 31 includes a plurality of single yarns 4. The aspect ratio of the warp 31 is represented by its thickness H and width L to L / H. The same applies to the weft thread 32.

When the aspect ratio of the cross section of the warp and weft is 1.5 or more, the raw water permeates uniformly between the single yarns, and the removal rate and the filtration life are improved. When the aspect ratio of the cross section of the warp and the weft is 10 or less, the misalignment of the woven fabric is suppressed, and the voids are evenly distributed in the winding body, so that the removal rate and the filtration life are improved.

When the diameter of the single yarn 4 constituting the warp and weft is 1 μm or more, a gap having an appropriate width is generated between the single yarns. Due to the presence of this gap, raw water can be preferentially passed between the single yarns rather than between the multifilaments. Since the metal oxide supported inside the single yarn near the center of the fiber bundle can efficiently contribute to the adsorption of the target substance, a high removal rate of the target substance and a long filtration life are realized. it can. The diameter d of the single yarn is preferably 5 μm or more, more preferably 10 μm or more.

The single yarn diameter d is 100 μm or less, preferably 60 μm or less, and more preferably 45 μm or less. When the single yarn diameter d is 100 μm or less, the area where the single yarn comes into contact with the raw water can be increased, and the adsorption rate can be increased. Further, since the metal oxide supported on the inside of the single yarn can efficiently contribute to the adsorption of the target substance, the life of the filter can be extended.

The number of single yarns constituting the warp and weft is 7 or more, preferably 12 or more, and more preferably 24 or more. By having 7 or more yarns, it is possible to reduce the number of warp yarns and weft yarns per inch required for uniform permeation of raw water between single yarns, and as a result, the number of intersections of warp yarns and weft yarns is reduced. Since the contact area with raw water can be increased and the metal oxide supported inside the single yarn near the center of the fiber bundle can efficiently contribute to the adsorption of the target substance, the removal rate and the filtration life are improved. To do.

Further, the number of single yarns constituting the warp and weft is 700 or less, preferably 400 or less, and more preferably 150 or less. When the number of yarns is 700 or less, the raw water easily flows between the single yarns instead of between the fiber bundles, and an excessive increase in pressure loss when the raw water flows between the single yarns can be reduced.

The warp and weft that make up the woven fabric have twists of 0 T / m or more and 100 T / m or less, more preferably 50 T / m or less, and even more preferably 10 T / m or less, respectively. When it is 100 T / m or less, a gap between single yarns can be secured, and when raw water is passed, water can be preferentially passed between single yarns instead of between multifilaments, and a fiber bundle can be passed. Since the metal oxide supported inside the single yarn near the center of the yarn can efficiently contribute to the adsorption of the target substance, a high removal rate of the target substance to be removed and a long filtration life can be realized.

Further, as a value indicating the density of the warp or weft of the woven fabric, there is a cover factor CF shown in the following equation.

CF = N × (D) ^1/2
N (book / inch): the number of meshes of the warp or weft that constitutes the woven fabric per inch, D: the multifilament diameter (dtex) of the warp or weft that constitutes the woven fabric.
The total value of each cover factor in the warp and weft is 1200 or more, more preferably 1300 or more, and further preferably 1800 or more. Further, it is preferably 2200 or less, more preferably 2100 or less, and further preferably 2000 or less.

When the total value of CF is 1200 or more, the gap between the adjacent warp yarns and the gap between the adjacent weft yarns can be reduced, the raw water flows preferentially between the single yarns, and the effective core material is the same. Since it is possible to surround the woven fabric and impart an appropriate water flow resistance even when water is passed through it, non-uniformity of the flow rate is unlikely to occur, and the removal rate and the filtration life can be increased. When the total value of CF is 2200 or less, it is possible to secure a gap between single yarns and maintain an appropriate water flow resistance.

In a general filter, raw water flows preferentially in the gaps inside the multifilament, that is, in the gaps between the fiber bundles rather than the gaps between the single yarns. Therefore, the contact area of the single yarn with the raw water is much smaller than the total surface area of the single yarn. That is, even if each single yarn has an adsorptive capacity, the single yarn existing near the center of the fiber bundle cannot sufficiently contribute to the removal of components in the raw water. In addition, since the components in the raw water adhere to the single yarn on the outside of the fiber bundle, the life of the filter expires before the adsorbent of the entire filter exerts its function.

On the other hand, since the woven fabric has the above structure, raw water easily passes through the inside of the multifilament, and a filter having a high adsorption rate, a large adsorption capacity, and a long life is realized.

4. Fibrous Adsorbent At least one of the warp or weft in a woven fabric that is a multifilament contains a fibrous adsorbent as a single yarn. The fibrous adsorbent adsorbs ions in the liquid. It is preferable that both the warp and the weft contain a fibrous adsorbent. In the woven fabric, the multifilament containing the fibrous adsorbent may be a part or all of the warp and weft. Further, the fibrous adsorbent may be a part or all of the single yarn contained in the multifilament. In order to increase the adsorption capacity and the adsorption rate, it is preferable that the single yarns constituting all the warp and weft yarns contained in the woven fabric are fibrous adsorbents, but in order to improve the strength or other performance, the woven fabric is used. It may contain a multifilament or a single yarn having no adsorptive capacity.

The cross-sectional shape of the fibrous adsorbent or a single yarn having no adsorption performance (referred to simply as "single yarn" unless otherwise specified) is not limited to a specific example, and may be circular or irregular. May be good. A variant is a shape other than a circle. The irregular shape is, for example, polygonal hexagon (preferably 3 to hexagonal); flat shape; lens type; the same number as a plurality of (preferably 3 to 8) convex parts called multilobes such as three leaves and hexagons. A shape in which recesses are alternately arranged can be adopted.

A single yarn with a modified cross section has a large specific surface area. Further, in a filter including a single yarn having a modified cross section, a wide gap can be secured between the single yarns, so that the flow resistance becomes small. Further, since the contact area with the raw water is increased, high adsorption performance can be obtained.

The degree of deformation of the cross section is preferably 1.2 or more and 6.0 or less. The degree of deformation is a value (R1 / R2) obtained by dividing the diameter R1 of the smallest circle including the cross section of the single yarn 4 by the diameter R2 of the largest circle that fits within the cross section of the single yarn 4 (FIG. 4). When the degree of deformation is 1.2 or more, the specific surface area of the single yarn becomes large, so that the contact area with raw water can be increased. Further, when the degree of deformation is 6.0 or less, thread breakage is unlikely to occur.

Fibrous adsorbents include, for example, ion exchange fibers capable of removing ions and metal particle-supporting fibers that can be removed by adsorbing inorganic ions such as boron, arsenic, phosphorus, and fluoride ions.

The ion exchange fiber contains a polymer compound having an ion exchange group.

A polymer compound having an ion exchange group has a cation exchange group such as a sulfonic acid group, a carboxy group, a phosphoric acid group or a hydroxyl group, or an anion exchange group such as a quaternary ammonium base or a tertiary amino group in the molecule. Including. In order to suppress the swelling of the polymer compound, the molecular chains may be cross-linked by covalent bonds at multiple points.

The cross-linking agent is copolymerized with a monomer having a carboxy group to suppress swelling, increase the density of cation exchange groups in the ion exchange fiber, and improve the ion exchange capacity.

As the cross-linking agent, paraformaldehyde, bifunctional acrylamide, bifunctional acrylate, bifunctional methacrylate and divinylbenzene are preferably used. Examples of bifunctional acrylamide include N, N'-methylenebisacrylamide. Examples of the bifunctional acrylate include 2-hydroxy-3-acryloyloxypropyl methacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, and the like. Examples of the bifunctional methacrylate include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and polyethylene glycol dimethacrylate.

Regarding ion-exchange fibers, a polymer compound having an ion-exchange group is formed, for example, by graft-polymerizing a vinyl monomer having a carboxy group with a substrate. A polymer compound having a carboxy group is a compound having a plurality of carboxy groups in the molecule, and is composed of a homopolymer of acrylic acid and methacrylic acid, a copolymer, an acrylic acid ester, a methacrylic acid ester, and maleic anhydride. A polymer obtained by hydrolyzing a copolymer can be mentioned.

The ion exchange capacity of the ion exchange fiber is preferably 1.0 meq / g or more, and more preferably 1.5 meq / g or more. When it is 1.0 meq / g or more, a life that can be practically used as an ion exchange fiber can be realized. The ion exchange capacity is preferably 8.0 meq / g or less, and more preferably 6.0 meq / g or less. When the ion exchange capacity is 8.0 meq / g or less, excessive swelling of the polymer compound having an ion exchange group is suppressed, so that clogging during water flow is less likely to occur.

As shown in FIG. 5, the metal particle-supporting fiber 2 contains a layer 21 of a polymer compound having an ion exchange group and metal particles 23 supported on at least the surface of the layer 21.

As shown in FIG. 5, the metal particle-supporting fiber 2 may have a central base material 24. By having the central base material 24, the strength of the metal particle-supporting fiber 2 can be maintained high and breakage can be suppressed. The central base material 24 does not contain the metal particles 23. The base material and the central base material 24 described in the description of the ion exchange fiber may be of the same type or different types, and may be, for example, a polyolefin such as polyethylene or polypropylene, a polyester such as polyethylene terephthalate or polycarbonate, or the like. Synthetic fibers such as polyamide, aromatic polyamide, acrylic, polyacrylonitrile, polyvinyl chloride, PTFE, halogenated polyolefin such as polyvinylidene fluoride, and natural fibers such as wool, silk and cotton, or blended yarns or blended fibers thereof. Threads can be used. Among these fibers, polyamide and polyester are particularly preferable as the fiber structure, nylon is particularly preferable for polyamide, and polyethylene terephthalate (PET) is particularly preferable for polyester.

The metal particles 23 are supported on at least at least the surface of the layer 21 of the polymer compound having an ion exchange group. Further, the metal particles 23 may also be supported inside the layer 21 of the polymer compound having an ion exchange group. Since the metal particles 23 are present inside the layer 21, the mass of the metal particles 23 per unit mass of the metal particle-supporting fibers 2 is larger than that of being supported only on the surface, and the metal particles 23 are ion-exchange groups. It becomes difficult to separate from the layer 21 of the polymer compound having.

The metal particles 23 or their precursors are bonded to the ion exchange group so that the metal particles are efficiently supported on the layer 21. The type of bond between the ion exchange group and the metal particle 23 is not particularly limited, and examples thereof include an ionic bond, a coordination bond, a metal bond, a hydrogen bond, and a van der Waals force bond.

From the viewpoint of supporting the metal particles of cerium hydroxide, the polymer compound having an ion exchange group is preferably a polymer compound having an anionic ion exchange group such as a carboxyl group, a sulfo group, or a phosphate group, and polystyrene sulfone is preferable. Examples thereof include acids, polyacrylic acid, polymethacrylic acid, and copolymers containing the above-mentioned polymer compound having an anionic ion exchange group. As will be described later, the metal particles of cerium hydroxide are particularly preferable metal particles from the viewpoint of ion removal performance.

The functional group density C (meq / g) of the ion exchange group is preferably 0.5 (meq / g) or more, and more preferably 1.0 (meq / g) or more in the woven fabric described later. .. When it is 0.5 (meq / g) or more, the supported metal is less likely to be peeled off even when water is passed. C (meq / g) is preferably 8.0 (meq / g), more preferably 5 (meq / g) or less. When it is 8.0 (meq / g) or less, excessive swelling is suppressed, so that clogging during water flow is less likely to occur.

C (meq / g) is measured as follows. The woven fabric is immersed in a strongly acidic aqueous solution to dissolve the metal particles, the residue (fibrous structure) is washed with water, vacuum dried at 50 ° C. for 3 hours, and the absolute dry mass W (g) is measured. Then, the ion exchange capacity based on the absolute dry mass W (g) is measured with respect to the residue by a conventional method using neutralization titration, and the value is C (meq / g).

The metal constituting the metal particles 23 can be arbitrarily selected depending on the adsorption target. For example, the metal particles include at least one metal selected from the group consisting of silver, copper, iron, titanium, zirconium and cerium. For example, when the adsorption target is boron, arsenic, phosphorus, or fluoride ion, metal oxides, metal hydroxides, and hydrates thereof can be mentioned.

From the viewpoint of adsorption capacity, the metal particles preferably contain at least one of a metal hydroxide and a metal hydroxide. Examples of the metal hydroxide and the metal hydroxide include a rare earth element hydroxide, a rare earth element hydroxide, a zirconium hydroxide, a zirconium hydroxide, an iron hydroxide, and an iron hydroxide. Examples of rare earth elements include scandium Sc with atomic number 21 and ytterbium Y with atomic number 39, and lanthanoid elements with atomic numbers 57 to 71, that is, lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, and promethium Pm. , Samarium Sm, Europium Eu, Cadrinium Gd, Terbium Tb, Dysprosium Dy, Holmium Ho, Elbium Er, Thurium Tm, Ytterbium Yb, Lutetium Lu. Among them, cerium is preferable from the viewpoint of ion removal performance, and tetravalent cerium is more preferable. A mixture of these hydroxides and / or hydroxides is also useful.

The water content of the metal particles is preferably 1% by mass or more, and more preferably 5% by mass or more. When the water content is 1% by mass or more, adsorption sites can be imparted to the inside of the particles, and the particles have sufficient adsorption ability. The water content is preferably 30% by mass or less, and more preferably 20% by mass or less. When the water content is 30% by mass or less, the density of the adsorption sites inside the particles can be increased, and the particles have sufficient adsorption ability.

The particle size of the metal particles is preferably 1 nm or more and 1000 nm or less. The particle size means the particle size of the dispersed state (primary particles) if each particle is dispersed, and the agglomerated state (2) if the particles are agglomerated. The particle size of the subatomic particle). The particle size of the metal particles is preferably 500 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less. When the particle size exceeds 1000 nm, the number of adsorption sites existing on the outer surface of the particles is reduced, and sufficient adsorption ability cannot be exhibited. The particle size of the metal particles is preferably 5 nm or more, more preferably 10 nm or more, and even more preferably 15 nm or more. Considering the aggregation of particles during the production of the adsorbent, the lower limit of the particle size is 1 nm.

The amount of metal particles supported in the woven fabric is 5% by mass or more, preferably 8% by mass or more, and more preferably 15% by mass or more. When the amount of metal particles supported is 5% by mass or more, a life that can be practically used as an adsorption fiber can be realized. On the other hand, the amount of metal particles supported is 60% by mass or less, preferably 50% by mass or less, and more preferably 40% by mass or less. When the amount of the metal particles carried is 60% by mass or less, it is possible to suppress the peeling of the metal particles during water flow or the clogging of the filter due to the peeling of the metal particles.

The method for measuring the amount of metal particles supported is shown below. First, the mass W1 of the metal particle-supporting fiber is weighed. Next, the metal particles are taken out by dissolving the adsorbent in a good solvent such as a strong alkali / strong acid aqueous solution or by combining a method of heating at 800 ° C. or higher with an electric furnace, and the mass W2 of the metal particles is weighed. The amount of the metal particles supported, that is, the mass ratio of the metal particles to the entire metal-supported fibers is (W2 / W1) × 100 (parts by mass).

In the filter of the present invention, in addition to the requirements of single yarn diameter, number of single yarns of multifilament, aspect ratio of cross section, and cover factor for the warp and weft of the woven fabric, at least one of the warp or weft of the woven fabric is ionized as a single yarn. By including a layer of a polymer compound having an exchange group, the water flow resistance is greatly reduced and the filtration performance is improved. The mechanism is not clear, but it is considered that the adjacent site between the single yarns is not a base material having no ion exchange group but a layer of a polymer compound having an ion exchange group.

5. Water purifier The above filters can be applied to water purifiers. A water purifier is a structure that can remove target components contained in raw water. By including the above-mentioned filter, the component to be removed in the raw water can be suitably removed, and a sufficient amount of permeated liquid until it breaks can be obtained.

The shape of the water purifier is not limited, such as a pot type or other gravity type or faucet type. As described above, it can also be used for gravity type water purifiers and the like that require low water flow resistance.

Further, the above-mentioned filter can be used alone as a water purifier or in combination with another filter or a separation membrane, such as the filter 16 shown in FIG. 1 and the casing 17 accommodating the filter 16.

FIG. 6 illustrates a water purifier provided with a hollow fiber membrane and a filter. The water purifier 6 shown in FIG. 6 includes a filter 16, a hollow fiber membrane 62, a casing 61, and a sealing material 63.

The filter 16 includes a core material 13 and a winding body 10 as described above. The upper part of the core material 13 is open at the upper part of the casing 61 (water supply port 611). Further, the bottom of the core material 13 and the surrounding body 10, that is, the bottom of the filter 16 is sealed by the sealing material 63. The upper part of the filter 16 is sealed by the upper lid of the casing 61.

The hollow fiber membrane 62 is arranged below the filter 16 in the casing 61. Both ends of the hollow fiber membrane 62 are open at the bottom of the casing 61 (water intake 612).

The casing 61 is a hollow columnar member as a whole, and houses the filter 16 and the hollow fiber membrane 62 inside. The casing 61 has openings at the upper part and the lower part thereof, which are connected to the core material 13 and the hollow fiber membrane 62, respectively.

6. Water purification method The above-mentioned filter is suitable for water purification. The water purification method may include passing raw water through the filter. Water is preferable as the raw water, and tap water and groundwater are exemplified. In particular, the above-mentioned filter is suitably used for removing inorganic ions in water. Examples of inorganic ions include hardness components and heavy metal ions. Specific examples of the hardness component include calcium ions and magnesium ions. Heavy metal ions are metal elements having a specific gravity of 4 or more, and specifically, lead, mercury, arsenic, copper, cadmium, etc. Examples include chromium, nickel, manganese, cobalt and zinc.

In the surrounding body of FIG. 1, raw water enters the perforated core material 13 from the water supply port (not shown) at the upper part of the casing 17 and moves to the surrounding body 10 through the holes 14 on the side surface of the perforated core material 13. The solute contained in the raw water is removed while the raw water passes between the fabrics 11 of the surrounding body 10. The permeated water flows from the side surface of the surrounding body to the space between the surrounding body and the casing 17, and flows out of the casing 17 from an outlet (not shown) at the lower part of the casing 17. As shown in FIG. 1, in the winding body 10, the radial direction coincides with the filtration direction.

In the form shown in FIG. 6, the raw water enters the core material 13 from the upper part of the casing 61 and passes through the surrounding body 10. The components in the raw water are adsorbed in the winding body 10, and the obtained permeated water is further filtered by the hollow fiber membrane 62. The water that has passed through the hollow fiber membrane 62 passes through the inside of the hollow fiber membrane 62 and is discharged from the lower part of the casing 61.

7. Method for producing fibrous adsorbent First, a method for producing an ion exchange fiber will be described.

The fiber that is the base material can be produced by melt spinning, electric field spinning, or wet spinning. In order to obtain a structure in which a plurality of ultrafine fibers are bundled, the sea-island melt spinning method is used, the base material is an island component, a component that is more soluble in an alkaline aqueous solution than an island component is a sea component, and a post-spinning alkaline aqueous solution is used. There is a method of dissolving only the sea component in, but it is not limited to this.

The method for producing a polymer compound having an ion exchange group is as follows.

By imparting an ion exchange group or a chelate group to the fiber as the base material, the fiber becomes capable of ion exchange. Examples of the ion exchange group imparted to the fiber include a strongly acidic cation exchange group such as a sulfonic acid group and a weakly acidic cation exchange group such as a carboxy group and a phosphoric acid group. Examples of the monomer having a sulfonic acid group include styrene sulfonic acid, vinyl sulfonic acid, 2-acrylamide-2 methyl propane sulfonic acid, and sodium salts and ammonium salts thereof. Examples of the monomer having a carboxyl group include acrylic monomers such as acrylic acid and methacrylic acid. In addition, although the monomer itself does not have an ion exchange group and / or a chelate group, examples of the monomer having a functional group that can be converted into an ion exchange group and / or a chelate group include acrylic acid ester, methacrylic acid ester, and methacrylic acid. Examples thereof include glycidyl, styrene, acrylonitrile, achlorine, and chloromethylstyrene. From the viewpoint of ion exchange capacity, it is particularly preferable to use an acrylic monomer.

As a method for imparting such a functional group to the fiber, it is preferable to graft-copolymerize the monomer having the above functional group to the fiber using an initiator, but an ion exchange group is irradiated with a gamma ray or an electron beam or the like. The monomer having the above may be copolymerized with the fiber. By graft-copolymerizing a monomer having an ion-exchange group onto a fiber, a layer of a polymer compound having an ion-exchange group is formed inside the fiber. Examples of the initiator include ammonium persulfate (APS), azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO) and the like. At the time of graft polymerization, a cross-linking agent may be added together with the monomer.

In particular, when a peroxide such as ammonium persulfate (APS) or benzoyl peroxide (BPO) is used as an initiator, an iron (II) salt, a sulfite, a sulfinate, a hydroxylamine or the like is simultaneously used as a reducing agent. By using it, the reaction can be further promoted.

In addition, tetramethylethylenediamine (TEMED), ethylenediaminetetraacetic acid (EDTA) and the like may be added as substances that promote radical polymerization.

By copolymerizing a monomer having an ion exchange group together with a cross-linking agent, the density of the ion exchange group is increased and the ion exchange capacity is improved.

Next, a method for producing the metal particle-supporting fiber will be described. The metal particle-supporting fiber is produced by supporting the metal particles on the above-mentioned ion exchange fiber, and specifically, the metal particle-supporting fiber is produced.
i) A solution of metal particles ii) A solution of a metal salt is prepared and brought into contact with an ion exchange fiber.

In i) above, it is preferable that the metal particles form nanocolloids. After immersing the ion exchange fiber in the nanocolloidal solution of the metal particles, the excess adhered particles are washed with water to obtain the metal particle-supporting fiber.

In ii) above, the type of metal salt forming the metal salt solution is not particularly limited, but nitrates, sulfates, chlorides, fluorides, bromides having metal ions exemplified in "4. Fibrous adsorbent" above. , Iodide, acetate, carbonate, chromate, or salt having a metal oxide ion of the metal exemplified in the above "4. Fibrous adsorbent".

By bringing the ion-exchange fiber into contact with the metal salt solution, the metal ion of the metal salt is adsorbed on the ion-exchange group, and if necessary, the metal ion of the metal salt is oxidized or reduced to form the ion-exchange fiber. Fine particles of metal oxide, metal hydroxide, or a single metal can be precipitated on the surface or inside. The method of oxidation / reduction is not particularly limited, and in addition to the conventional method using a chemical oxidizing agent or a reducing agent, a catalyst, light irradiation, or the like can be used in combination. Further, by contacting the metal salt solution with the ion exchange fiber and then adding an alkali to the solution, it is also possible to precipitate metal oxide or metal hydrous oxide particles on the surface or inside of the fiber.

The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these Examples. Further, all the "single yarns" in the examples are "fibrous adsorbents".

<Making a filter>
The woven fabric produced by the following method was wound around a perforated core material having an outer diameter of 10 mm and a length of 230 mm so as to have a thickness of 20 mm. An epoxy resin adhesive was applied to the woven fabric surrounding portions on both end faces of the surrounding body. The bottom of one end surface was sealed with a disk plate, and the enclosure was loaded into a case having an inner diameter of 54 mm to prepare a filter. In the case, the target raw water is passed from the inside of the effective core material at one end of the surrounding body toward the outside of the woven fabric surrounding layer, and the raw water that has passed through the woven fabric surrounding layer is collected, and the opposite end is collected. It has a structure that can be discharged from the side.

<Single yarn diameter d>
The woven fabric was immersed in RO water (reverse osmosis filtered water) for 24 hours, and then the diameter of 10 single yarns when observed with a microscope was measured, and the average value was taken as the single yarn diameter.

<Aspect ratio of cross section of warp or weft>
The woven fabric is immersed in RO water (back-penetration filtered water) for 24 hours, and the cross section perpendicular to the weft or warp is observed with a microscope, and the maximum in the thickness direction in the cross section of the warp or the fiber bundle constituting the weft. The ratio of the maximum length in the direction perpendicular to the thickness direction to the length was defined as the aspect ratio, and 10 fibers were measured for each of the warp and weft fiber bundles, and the average value of each was defined as the aspect ratio.

<Cover Factor CF>
The warp and weft were extracted from the woven fabric, and the weight (g) per 100,000 m was measured by 10 each, and the average diameter of each was taken as the warp or the multifilament diameter D (dtex) of the weft. The woven fabric was observed from the upper surface with a microscope, the number of warp threads and weft threads per inch was measured at 10 points each, and the average value of each was taken as N (thread / inch), and CF was calculated from the above formula. The total CF is twice that of CF.

<Initial removal rate, filtration life>
As raw water, in the case of ion-exchanged fibers, an aqueous solution having a calcium chloride concentration of 0.2 mmol / L and a sodium hydrogen carbonate concentration of 0.2 mmol / L was used, and the removal rate of calcium ions was measured. Used an aqueous solution of 1.0 × 10 ^-3 mmol / L boric acid as raw water, and the removal rate of boron was measured. Raw water was passed through the filter so that the space velocity SV value was 100 (hr ^-1).

Raw water filters the filter 10bed vol. 10 mL was sampled for each permeation, and the calcium ion concentration or boron concentration in the permeated solution was measured by ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrum) to calculate the calcium ion removal rate or boron removal rate. .. bed vol. Is the value obtained by dividing the volume of the permeate by the volume of the packed bed.

10bed vol. The removal rate after permeation is defined as the "initial removal rate", and the bed vol. Was defined as "filtration life".

<Water flow resistance>
Pure water was passed through the filter so that the space velocity SV value was 100 (hr ^-1 ), and the pressure loss, which is the difference between the pressure between the filter and the filter, was measured.

<Amount of metal particles supported>
A part of the woven fabric was cut out and its mass W1 was weighed. Next, the metal particles were taken out by dissolving the woven fabric in a good solvent such as a strong alkali or a strong acid aqueous solution, or heating at 800 ° C. or higher by an electric furnace, or a combination of these methods, and the mass W2 of the metal particles was weighed. .. The amount of the metal particles supported, that is, the mass ratio of the metal particles to the entire metal-supported fibers was calculated by (W2 / W1) × 100 (parts by mass).

(Reference example 1)
A woven fabric was produced from 125 decitex, 34 filament nylon 6 fibers using a plain weave machine with a twist of 0 T / m for both warp and weft and 60 meshes (pieces / inch).

0.9 parts by weight of methacrylic acid, an aqueous solution containing 0.3 parts by weight of acrylic acid, Na0.03 parts by hydroxy sulfinic acid, EDTA · _2Na · 2H 2 O0.01 parts by mass of ammonium persulfate 0.01 parts by weight 1 part by mass of the above woven fabric was immersed in 4 parts by mass and allowed to stand at 70 ° C. for 1 hour. After standing, it was taken out from the aqueous solution and washed with RO water.

In this way, a woven fabric made of ion exchange fibers was produced. A filter was prepared from the obtained woven fabric by the above-mentioned method.

(Reference example 2)
A filter was produced in the same manner as in Example 1 except that the twist degree of the warp and weft was 80 T / m.

(Example 1)
A woven fabric made of fibers carrying cerium hydroxide nanoparticles was produced by the following operation.

A woven fabric was produced using 170 decitex, 34 filament nylon 6 fibers, a twist of 0 T / m, and a plain weave machine with a number of meshes of warp and weft of 60 (pieces / inch).

The fabric about 1 part by weight, 0.375 parts by mass of methacrylic acid, 0.125 parts by weight of acrylic acid, Na0.15 parts by hydroxy sulfinic acid, EDTA · _2Na · 2H 2 O0.05 parts by mass of ammonium persulfate It was immersed in 100 parts by mass of an aqueous solution containing 0.05 parts by mass and allowed to stand at 70 ° C. for 1 hour. After standing, it was taken out and washed with RO water to obtain a woven fabric made of ion-exchange fibers. The ion-exchange fiber was immersed in a 1 mol / L NaOH aqueous solution at room temperature for 3 hours to convert the carboxyl group, which is a functional group of the ion-exchange fiber, from H-type to Na-type. Subsequently, the woven fabric was immersed in a 0.2 mol / L ₃ _{aqueous solution of Ce (NO 3} ) at room temperature for 3 hours to convert the functional group from Na type to Ce type. Then, cerium hydroxide was precipitated near the surface of the woven fabric by immersing it in a 0.2 mol / L NaOH aqueous solution at room temperature for 3 hours. This was washed with RO water.
A filter was prepared from the obtained woven fabric by the above-mentioned method. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Example 2)
A woven fabric was prepared using 115 decitex, 34 filament nylon 6 fibers, a twist of 0 T / m, and a plain weave machine with a mesh number of warp and weft of 60 (pieces / inch).

Cerium hydroxide was supported on this woven fabric by the same method as in Example 1. However, methacrylic acid was 0.9 parts by mass and acrylic acid was 0.3 parts by mass. A filter was prepared from the obtained woven fabric by the above-mentioned method. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Example 3)
A woven fabric was prepared using 80 decitex, 34 filament nylon 6 fibers, a twist of 0 T / m, and a plain weave machine with a mesh number of 60 (pieces / inch) of warp and weft. Cerium hydroxide was supported on this woven fabric by the method described in Example 1. However, methacrylic acid was 3.75 parts by mass and acrylic acid was 1.25 parts by mass.
A filter was prepared from the obtained woven fabric by the above-mentioned method. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Example 4)
A filter was produced in the same manner as in Example 2 except that the twist degree of the warp and weft was 80 T / m. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Example 5)
A filter was produced by the same method as described in Example 2 except that the number of meshes of the warp and weft was 42 (pieces / inch). Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Example 6)
A filter was prepared in the same manner as in Example 2 except that 115 decitex and 376 filament nylon 6 fibers were used. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Example 7)
A filter was prepared in the same manner as in Example 2 except that 115 decitex and 122 filaments of nylon 6 fibers were used. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Example 8)
A filter was prepared in the same manner as in Example 2 except that 115 decitex, 7 filament nylon 6 fibers were used. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Example 9)
A filter was prepared by the same method as described in Example 2 except that the twill structure was twill weave. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Example 10)
A filter was produced by the same method as described in Example 2 except that the weave structure was satin weave. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Example 11)
A filter was produced in the same manner as in Example 2 except that 115 decitex, 34 filaments, and three-leaf nylon 6 fibers having a single yarn shape having a degree of deformation of 3.0 were used. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Comparative Example 1)
A woven fabric was prepared using 235 decitex, 34 filaments of polyethylene terephthalate fiber, a twist of 0 T / m, and a plain weave machine with a mesh number of 60 (pieces / inch) of warp and weft.

Both sides of this woven fabric were subjected to corona discharge treatment under a nitrogen atmosphere at a surface treatment strength of 30 W / min / m ^2. The treated woven fabric was immersed in a nanocolloidal solution of cerium oxide (solvent: water, concentration: 5% by mass) at room temperature for 1 day. Then, washing with water was performed to remove excess cerium oxide nanocolloidal solution.

Thus, a woven adsorbent having polyethylene terephthalate fiber and cerium oxide bonded to the functional group thereof was obtained.

A filter was prepared from the obtained woven fabric by the above method.

(Comparative Example 2)
A filter was produced in the same manner as in Comparative Example 1 except that the twist of the warp and weft was 80 T / m.

(Comparative Example 3)
A filter was produced by the same method as that described in Comparative Example 1 except that the number of meshes of the warp and weft was 50 (pieces / inch).

(Comparative Example 4)
A filter was prepared by the same method as that described in Comparative Example 1 except that the twill weave was used instead of the plain weave.

(Comparative Example 5)
A filter was prepared by the same method as that described in Comparative Example 1 except that the satin weave was used instead of the plain weave.

(Comparative Example 6)
A filter was produced in the same manner as in Comparative Example 1 except that the twist of the warp and weft was 750 T / m.

(Comparative Example 7)
A filter was produced by the same method as that described in Comparative Example 1 except that the number of meshes of the warp and weft was 80 (pieces / inch).

(Comparative Example 8)
Using one filament PET fiber having a fiber diameter of 25 μm, a woven fabric was produced with a plain weave machine having 220 (pieces / inch) meshes of warp and weft threads. For this woven fabric, a woven fabric made of fibers carrying cerium oxide nanoparticles was produced by the method described in Comparative Example 1. The obtained woven fabric was used to prepare a filter by the method described above.

(Comparative Example 9)
A filter was produced by the same method as that described in Comparative Example 1 except that the number of meshes of the warp and weft was 30 (pieces / inch).

(Comparative Example 10)
A filter was produced in the same manner as in Example 2 except that the twist degree of the warp and weft was 750 T / m. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Comparative Example 11)
A filter was produced by the same method as described in Example 2 except that the number of meshes of the warp and weft was 30 (pieces / inch). Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Comparative Example 12)
A filter was prepared in the same manner as in Example 2 except that 115 decitex and 1 filament nylon 6 fibers were used. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Comparative Example 13)
A filter was produced by the same method as in Example 2 except that nylon 6 fibers having a fiber diameter of 0.4 μm and 900 filaments were used and the number of meshes of warp and weft was 220 (pieces / inch). did. Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Comparative Example 14)
A filter was produced by the same method as described in Example 2 except that the number of meshes of the warp and weft was 80 (pieces / inch). Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

(Comparative Example 15)
A filter was produced in the same manner as in Example 2 except that the fiber diameter was 16 μm and one filament of nylon 6 fibers was used and the number of meshes of the warp and weft was 220 (pieces / inch). Further, when the cross section of the single yarn was observed using SEM-EDX and Na was mapped, Na was distributed near the surface of the single yarn, and the presence of a polymer compound layer containing a carboxy group which is an ion exchange group was found. It was suggested.

Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and modifications can be made without departing from the intent and scope of the present invention.

The filter of the present invention is suitably used for removing inorganic components dissolved in water.

10 Volume 11 Woven fabric 13 Core material 14 Holes 16 Filter 17 Casing 31 Warp (multifilament)
32 Weft (multifilament)
4 Single thread H Multifilament thickness L Multifilament width R1 Minimum circle diameter including the cross section of the single thread 4 R2 Maximum circle diameter that fits within the cross section of the single thread 4 Metal particle carrying fiber 21 Polymer compound Layer 22
23 Metal particles 24 Central base material 6 Water purifier 61 Casing 62 Hollow fiber membrane 63 Encapsulant 611 Water supply port 612 Water intake port

Claims

A liquid filtration filter including a perforated core material and a woven fabric surrounded by the outer circumference of the perforated core material.
A filter in which the woven fabric satisfies the following conditions (a) to (d).
(A) The warp and the weft include a multifilament containing 7 to 700 single yarns having a diameter of 1 μm to 100 μm, and the single yarns contained in the warp and the weft are thick in each cross section perpendicular to the longitudinal direction of the warp and the weft. There are three or more laminated parts in the direction, and the aspect ratio of the cross section of the warp and weft is 1.5 to 10.
(B) The total cover factor of the warp and weft is 1200 or more and 2200 or less.
(C) At least one of the warp or weft contains, as the single yarn, a fibrous adsorbent having a layer of a polymeric compound having an ion exchange group; metal particles supported on at least the surface of the layer (c). d) The amount of the metal particles supported is 5 to 60% by mass with respect to the mass of the woven fabric.
The filter according to claim 1, wherein at least one of the warp or weft contains a multifilament having a twist of 0 T / m to 100 T / m.
The woven fabric has a satin weave or a modified structure thereof.
The filter according to any one of claims 1 and 2.
The ion exchange group is at least one anionic ion exchange group selected from a carboxy group, a sulfo group and a phosphate group.
The filter according to any one of claims 1 to 3.
The metal particles contain at least one metal atom selected from the group consisting of silver, copper, iron, titanium, zirconium and cerium.
The filter according to any one of claims 1 to 4.
A step of supplying water to the filter according to any one of claims 1 to 5.
A method for producing purified water, which comprises a step of recovering water that has passed through the filter.
A housing with a water supply port and an intake port,
The filter according to any one of claims 1 to 5, which is housed in the housing.
Water purifier with.