Water purification filter

Abstract

The purpose of the present invention is to provide a water purification filter that is capable of removing an organic chlorine compound and that has excellent capacity to filter soluble lead. This water purification filter includes a cylindrical molded body. The molded body has, in the radial direction, a body part including a first layer and a second layer, and a cavity inside the body part. The first layer contains a lead removal material, the second layer contains activated carbon and the lead removal material, the first layer is provided on the side of the second layer in the radial direction where purified water flows out, and the first layer has a higher content ratio of the lead removal material than the second layer.

Description

Water purification filter

[0001] The present invention relates to a water purification filter.

[0002] (a) A cylindrical container, (b) a water passage forming member disposed along the inner peripheral surface of the container, extending in the axial direction and circumferential direction of the container, and forming a water passage for raw water, (c) a granular ion exchange resin layer disposed along the inner peripheral surface of the water passage forming member for removing hardness components in the raw water by ion exchange, and (d) an activated carbon layer disposed on the center side of the container along the inner peripheral surface of the ion exchange resin layer. There is known a water softening and purification device that allows raw water flowing in from an inlet and reaching the water passage formed by the water passage forming member to pass through the ion exchange resin layer and the activated carbon layer in this order from the outer peripheral side to the center side in a direction perpendicular to the axis, thereby softening and purifying the raw water (see, for example, Patent Document 1). According to this water softening and purification device, the passing distance (water passing distance) of the raw water through the ion exchange resin layer and the activated carbon layer can be shortened, and the water passing area can be increased, and it is said that the water passing resistance can be suppressed to a small value and the raw water can be flowed at a large flow rate.

[0003] Japanese Unexamined Patent Application Publication No. 2014-100633

[0004] In recent years, water purification filters are required to remove dissolved lead contained in tap water in trace amounts in addition to organic chlorine compounds. Here, to remove organic chlorine compounds, it is conceivable to use activated carbon. On the other hand, to remove dissolved lead, it is conceivable to use lead removal materials such as ion exchange resins, ion exchange fibers, metal silicates such as titanium silicate and aluminum silicate, hydroxyapatite, titanium oxide, and bone charcoal. And since the water softening and purification device of Patent Document 1 includes an activated carbon layer and an ion exchange resin layer, it has a certain degree of performance in removing organic chlorine compounds and dissolved lead. However, the water softening and purification device of Patent Document 1 did not have sufficient filtration ability for dissolved lead.

[0005] The present invention solves the above problems, and the main object is to provide a water purification filter that can remove organic chlorine compounds and has excellent filtration ability for dissolved lead.

[0006] In order to solve the above problems, the inventors of the present invention have investigated and found that a water purification filter comprising a cylindrical molded body, wherein the molded body has a main body portion comprising a first layer and a second layer in the radial direction, and a cavity portion located inside the main body portion, wherein the first layer contains a lead removal material, the second layer contains activated carbon and a lead removal material, the first layer is provided on the side from which purified water flows out relative to the second layer in the radial direction, and the first layer has a higher lead removal material content than the second layer, can effectively remove organochlorine compounds and has excellent filtration capacity for dissolved lead. The present invention was completed by further diligent investigation based on these findings.

[0007] In other words, the present invention provides the invention in the following embodiments: <1> A water purification filter comprising a cylindrical molded body, wherein the molded body has, in the radial direction, a main body portion comprising a first layer and a second layer, and a cavity portion located inside the main body portion, the first layer containing a lead removal material, the second layer containing activated carbon and a lead removal material, the first layer being provided in the radial direction on the side from which purified water flows out of the second layer, and the first layer having a higher lead removal material content than the second layer, a water purification filter. <2> The water purification filter according to <1>, wherein the first layer further contains activated carbon. <3> The second layer contains activated carbon and a lead removal material, and has a specific surface area of ​​500 to 800 cm². 3 The C layer has a density of 1 / g and a mesopore volume ratio of 20-29.9%, and contains activated carbon and lead removal material, with a specific surface area of ​​800-1200 cm². 3 A water purification filter according to <1> or <2>, comprising an F layer having a density of / g and a mesopore volume ratio of 30 to 40%. <4> A filtration method for obtaining filtered water by passing raw water through a water purification filter according to any one of <1> to <3>.

[0008] The water purification filter of the present invention can effectively remove organochlorine compounds (e.g., chloroform, dichloroethylene, trichloroethylene, tetrachloroethylene, and total trihalomethanes) and has excellent filtration capacity for dissolved lead. Furthermore, the water purification filter of the present invention can also effectively remove fluorine-containing organic compounds.

[0009] It is a schematic diagram showing an embodiment of a molded body constituting the water purification filter of the present invention. It is a schematic diagram showing another embodiment of a molded body constituting the water purification filter of the present invention. It is a schematic diagram showing another embodiment of a molded body constituting the water purification filter of the present invention. It is a schematic diagram showing another embodiment of a molded body constituting the water purification filter of the present invention. It is a schematic diagram showing another embodiment of a molded body constituting the water purification filter of the present invention. It is a schematic diagram showing another embodiment of a molded body constituting the water purification filter of the present invention. It is a schematic diagram showing an embodiment of a manufacturing method of a molded body constituting the water purification filter of the present invention.

[0010] 1. Water purification filter The water purification filter of the present invention includes a cylindrical molded body, and the molded body has a main body portion including a first layer and a second layer in the radial direction, and a hollow portion inside the main body portion. The first layer contains a lead removal material, the second layer contains activated carbon and a lead removal material, the first layer is arranged on the side where purified water flows out with respect to the second layer in the radial direction, and the first layer has a higher content ratio of the lead removal material than the second layer.

[0011] Hereinafter, an embodiment of a molded body constituting the water purification filter of the present invention will be described with reference to the drawings. However, the form of the water purification filter of the present invention is not limited to this embodiment. Note that the drawings are only schematic diagrams, and the actual shape and the like may be different.

[0012] FIGS. 1 to 6 are schematic diagrams showing an embodiment of a molded body constituting the water purification filter of the present invention. As shown in FIGS. 1 to 6, a molded body 1 constituting the water purification filter of the present invention is cylindrical, and in the radial direction, it has a main body portion 4 including a first layer 2 and a second layer 3 (3A and 3B), and a hollow portion 5 inside the main body portion 4.

[0013] Figures 1 to 3 show an in-out type water filter in which the raw water to be filtered is introduced into the cavity 5, the raw water permeates radially outward through the molded body 1, and the filtered purified water flows out from the outer circumference of the molded body 1. On the other hand, Figures 4 to 6 show an out-in type water filter in which the raw water to be filtered is introduced to the outer circumference of the molded body 1, the raw water permeates radially inward through the molded body 1, and the filtered purified water flows out into the cavity 5.

[0014] As shown in Figures 2 and 5, the second layer 3 may contain activated carbon and lead removal material and be composed of multiple layers with different specific surface areas and mesopore volume ratios. Figures 2 and 5 show the second layer 3 being composed of two layers, layer 3A and layer 3B.

[0015] As shown in Figures 1 to 6, the first layer 2 is provided radially on the side from which purified water flows out to the second layer 3. Furthermore, the first layer 2 must have a higher lead removal agent content than the second layer 3.

[0016] As shown in Figures 3 and 6, the main body 4 may include another layer 6 in addition to the first layer 2 and the second layer 3. The other layer 6 contains activated carbon and lead removal material and is provided radially on the side from which purified water flows out to the first layer 2. For example, the other layer 6 has a lower lead removal material content than the first layer.

[0017] The configuration of the water purification filter of the present invention will be described in detail below.

[0018] <Molded body> The molded body 1 constituting the water purification filter of the present invention has, in the radial direction, a main body portion 4 including a first layer 2 and a second layer 3, and a cavity portion 5 located inside the main body portion 4.

[0019] <First Layer> The first layer 2 contains a lead removal agent. Examples of lead removal agents include ion exchange resin, titanium silicate, aluminum silicate, hydroxyapatite, titanium oxide, and bone char. One of these may be used, or two or more may be used in combination. Of these, ion exchange resin is preferred.

[0020] Examples of ion exchange resins include weakly acidic cation exchange resins, strongly acidic cation exchange resins, weakly basic anion exchange resins, and strongly basic anion exchange resins. These may be used individually or in combination of two or more. By using ion exchange resins, the removal performance of dissolved lead can be further enhanced. Of these, weakly acidic cation exchange resins are preferred, more preferably weakly acidic cation exchange resins having carboxyl groups, even more preferably weakly acidic cation exchange resins in which the hydrogen atoms of the carboxyl groups are substituted with alkali metals and / or alkaline earth metals, and particularly preferably weakly acidic cation exchange resins in which the hydrogen atoms of the carboxyl groups are substituted with sodium and / or calcium. Furthermore, weakly acidic cation exchange resins having carboxyl groups are preferably polyacrylate or polymethacrylate-based weakly acidic cation exchange resins.

[0021] Examples of ion exchange resin forms include powdered ion exchange resin, granular ion exchange resin, and fibrous ion exchange resin (also called ion exchange fiber). These may be used individually or in combination of two or more. From the viewpoint of increasing the flow rate of the water purification filter, fibrous ion exchange resin (ion exchange fiber) is preferred.

[0022] In the first layer 2, the content of the lead removal agent is not particularly limited, but for example, it is 60 to 100% by mass, and preferably 60 to 80% by mass from the viewpoint of improving the moldability of the first layer 2. The first layer 2 has a higher content of lead removal agent than the second layer 3, for example, 10% or more by mass, preferably 20 to 99% by mass, more preferably 30 to 90% by mass, and even more preferably 50 to 80% by mass. Also, among the multiple layers contained in the molded body 1, the first layer 2 may be the layer with the highest content of lead removal agent.

[0023] The first layer 2 may contain materials other than lead remover.

[0024] Other materials include, for example, binder components. Examples of binder components include heat-fusible resins and fibrillated fibers. These may be used individually or in combination of two or more. The heat-fusible resin and fibrillated fibers play a role in further enhancing the moldability of the first layer 2. In this invention, "heat-fusible resin" means a resin that exhibits fusion properties when heated. In this invention, "fibrillated fiber" means a fiber in which fibrils (small fibers) present inside the fiber are exposed on the fiber surface by friction or the like, resulting in a fuzzy and frayed fiber surface.

[0025] Examples of the form of the heat-fusible resin include powdered heat-fusible resin, powdered heat-fusible resin, and heat-fusible fibers. These may be used individually or in combination of two or more. In this invention, "heat-fusible fiber" means a fiber that exhibits fusion properties when heated.

[0026] Examples of heat-sealable resins include olefin resins (e.g., polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, etc.), vinyl acetate resins (e.g., polyvinyl acetate, vinyl acetate-vinyl chloride copolymer, etc.), polyvinyl alcohol resins (e.g., polyvinyl alcohol, ethylene-vinyl alcohol copolymer, etc.), acrylic resins, styrene resins, low-melting-point polyester resins, polyamide resins, and thermoplastic polyurethane resins. These may be used individually or in combination of two or more.

[0027] When the first layer 2 contains a heat-fusible resin, the melting point of the heat-fusible resin (or softening point if no melting point exists; the same applies hereinafter) is preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 130°C or lower. In this invention, the melting point is the temperature that gives the extreme value of the melting absorption curve measured using a differential scanning calorimeter (for example, PerkinElmer DSC7) at a heating rate of 20°C / min.

[0028] From the viewpoint of ease of heat treatment, the heat-fusible fiber is preferably a heat-fusible fiber formed from two or more polymer components with different melting points or softening points, and more preferably a core-sheath type heat-fusible fiber having a core-sheath structure in which a high-melting-point polymer is the core and a low-melting-point polymer (heat-fusible resin) is the sheath. Examples of core-sheath type heat-fusible fibers include polyolefin fibers in which the core is polypropylene and the sheath is modified polyethylene, fibers in which the core is polyethylene terephthalate and the sheath is polyolefin, and polyester fibers in which the core is polyethylene terephthalate and the sheath is a low-melting-point (low-softening-point) polyester. Examples of the low-melting-point polyester include copolymerized polyethylene terephthalate obtained by copolymerizing copolymer components such as isophthalic acid. One of these may be used, or two or more may be used in combination. The melting point of the polymer in the core is preferably 20°C or more higher than the melting point of the polymer in the sheath, and more preferably 30°C or more higher. The melting point of the polymer in the core is specifically 150 to 300°C, preferably 200 to 300°C, which is 20°C or more higher than the melting point of the polymer in the sheath, preferably 30°C or more, more preferably 50°C or more, and even more preferably 100°C or more.

[0029] Examples of fibrillated fibers include acrylic fibers, polyethylene fibers, cellulose fibers, and aramid fibers. The water filtration rate of fibrillated fibers, measured according to JIS P 8121-2:2012, is, for example, 1 to 300, preferably 10 to 200.

[0030] The first layer 2 preferably contains a heat-fusible resin as a binder component, more preferably a heat-fusible fiber, and even more preferably a core-sheath type heat-fusible fiber.

[0031] If the first layer 2 contains a binder component, the proportion of the binder component in the first layer 2 is not particularly limited, but is, for example, 20 to 40% by mass, and preferably 20 to 30% by mass from the viewpoint of further improving the moldability of the first layer 2.

[0032] Furthermore, the first layer 2 may include activated carbon as another material. Including activated carbon in the first layer 2 can improve the removal performance of organochlorine compounds. Examples of activated carbon include powdered activated carbon, granular activated carbon, and fibrous activated carbon. These may be used individually or in combination of two or more. Of these, fibrous activated carbon is preferred from the viewpoint of further increasing the strength of the first layer 2 as an aggregate. The specific surface area of ​​the activated carbon contained in the first layer 2 is preferably 600 to 900 m². 2 / g, more preferably 700-900m 2 / g, more preferably 800-900m 2 The value is / g. In this invention, the specific surface area of ​​the activated carbon is calculated from the point where the relative pressure is 0.1 using the BET method, with the nitrogen adsorption isotherm at 77K obtained using a specific surface area measuring device.

[0033] When the first layer 2 contains activated carbon, the proportion of activated carbon in the first layer 2 is not particularly limited, but is, for example, 1 to 10% by mass, and more preferably 3 to 10% by mass, and more preferably 5 to 10% by mass, from the viewpoint of further improving the removal performance of organochlorine compounds.

[0034] The form of the first layer 2 is not particularly limited as long as it is cylindrical, and for example, a form in which a nonwoven fabric containing at least a lead removal agent is wound around the cavity 5 is included. Examples of the nonwoven fabric include dry nonwoven fabrics and wet nonwoven fabrics. Examples of dry nonwoven fabrics include nonwoven fabrics made of short fiber structures obtained by airlaid or carding (card web method), and needle-punched nonwoven fabrics which are laminated and integrated by needle punching the nonwoven fabric. Examples of wet nonwoven fabrics include nonwoven fabrics obtained by wet papermaking, in which a solution containing a lead removal agent is mixed and sheared using equipment such as a pulper, beater, and refiner to produce a uniformly dispersed slurry, and the obtained slurry is flowed onto a wire, dewatered, and dried.

[0035] The thickness of the nonwoven fabric forming the first layer 2 is not particularly limited, but is, for example, 0.1 to 1.0 mm, and preferably 0.2 to 0.5 mm. In this invention, the thickness of the nonwoven fabric forming the first layer 2 and the second layer 3 is determined by measuring the thickness at three arbitrary points using a thickness gauge and adopting the average value of the thicknesses at those three points.

[0036] The basis weight of the nonwoven fabric forming the first layer 2 is not particularly limited, but for example, 40 to 100 g / m² 2 Preferably 50 to 90 g / m² 2 In this invention, the basis weight of the nonwoven fabrics forming the first layer 2 and the second layer 3 is a value measured in accordance with Method A (JIS method) of 8.3.2 "Mass per unit area under standard conditions" of JIS L 1096:2010 (Test methods for woven and knitted fabrics).

[0037] In the molded body 1, the thickness of the first layer 2 is not particularly limited, but for example, it is 2 mm or more, and preferably 4 to 10 mm. In this invention, the thickness of the first layer 2 and the second layer 3 is determined by measuring the thickness of any two points using a caliper and adopting the average value of the thicknesses of those two points.

[0038] In the molded body 1, the mass ratio of the first layer 2 to the total mass of the first layer 2 and the second layer 3 (= (mass of the first layer 2) / (mass of the first layer 2 + mass of the second layer 3) × 100) is not particularly limited, but for example it is 5 to 30 mass%, preferably 10 to 25 mass%, and more preferably 15 to 25 mass%.

[0039] <Second Layer> The second layer 3 contains activated carbon and lead removal material. The second layer 3 is located radially on the side where raw water flows into the first layer 2, and has a lower lead removal material content than the first layer 2.

[0040] Like the water purification filter of the present invention, first, raw water is passed through the second layer 3 having a lower content ratio of the lead removal material than the first layer 2, and then the permeated water is passed through the first layer 2 having a higher content ratio of the lead removal material than the second layer 3, whereby organic chlorine compounds (for example, chloroform, dichloroethylene, trichloroethylene, tetrachloroethylene, and total trihalomethane, etc.) can be effectively removed, and the filtering ability of dissolved lead can be improved.

[0041] Examples of the activated carbon include powdered activated carbon, granular activated carbon, and fibrous activated carbon. These may be used alone or in combination of two or more. Among these, from the viewpoint of further enhancing the strength of the second layer 3 as an aggregate, fibrous activated carbon is preferably used. Further, the specific surface area of the activated carbon contained in the second layer 3 is preferably 1000 to 3000 m 2 / g, more preferably 1000 to 2500 m 2 / g, still more preferably 1000 to 2000 m 2 / g.

[0042] In the second layer 3, the content ratio of the activated carbon is not particularly limited, but for example, it is 60 to 90% by mass, and from the viewpoint of further improving the effects of the present invention, it is preferably 70 to 85% by mass.

[0043] Examples of the lead removal material include ion exchange resin, titanium silicate, aluminum silicate, hydroxyapatite, titanium oxide, and bone charcoal. These may be used alone or in combination of two or more. Among these, ion exchange resin is preferably used.

[0044] Since the ion exchange resin is as described in the column of <First Layer> including preferred embodiments, it will be omitted.

[0045] In the second layer 3, the content ratio of the lead removal material is not particularly limited, but for example, it is 1 to 20% by mass, and from the viewpoint of further improving the effects of the present invention, it is preferably 5 to 20% by mass, more preferably 5 to 15% by mass.

[0046] The second layer 3 can contain other materials other than the activated carbon and the lead removal material.

[0047] Other materials include, for example, binder components. Examples of binder components include heat-fusible resins and fibrillated fibers. These may be used individually or in combination of two or more. The heat-fusible resins and fibrillated fibers play a role in further enhancing the moldability of the second layer 3.

[0048] The heat-fusible resin and fibrillated fibers are described in the section on <First Layer> above, including preferred embodiments, and are therefore omitted here.

[0049] The second layer 3 preferably contains, as a binder component, a heat-fusible resin and fibrillated fibers, more preferably heat-fusible fibers and fibrillated fibers, and even more preferably core-sheath type heat-fusible fibers and fibrillated fibers.

[0050] If the second layer 3 contains a binder component, the proportion of the binder component in the second layer 3 is not particularly limited, but for example, it is 5 to 30% by mass, and from the viewpoint of further improving the moldability of the second layer 3, it is preferably 8 to 20% by mass, and more preferably 10 to 15% by mass.

[0051] As shown in Figures 2 and 5, the second layer 3 may be composed of multiple layers with different specific surface areas and mesopore volume ratios (pore volume with a pore diameter of 2 to 50 nm). Figures 2 and 5 show a case where the second layer 3 is composed of two layers, layer 3A and layer 3B.

[0052] The second layer 3 contains activated carbon and lead removal material, and has a specific surface area of ​​500 to 800 cm². 3 A C layer (3A) with a density of 1 / g and a mesopore volume ratio of 20-29.9%, along with activated carbon and lead removal material, and a specific surface area of ​​800-1200 cm². 3It is preferable to include an F layer (3B) having a concentration of / g and a mesopore volume ratio of 30-40%. In Figure 2, the C layer (3A) is shown as being radially outward and the F layer (3B) as being radially inward, but it may also be the case that the C layer (3A) is radially inward and the F layer (3B) is radially outward. Also, in Figure 5, the C layer (3A) is shown as being radially inward and the F layer (3B) as being radially outward, but it may also be the case that the C layer (3A) is radially outward and the F layer (3B) is radially inward. From the viewpoint of further improving the filtration flow rate, it is preferable that the C layer (3A) is provided radially on the side from which purified water flows out of the F layer (3B). The components contained in the C layer (3A) and the F layer (3B), and their respective content ratios are as described above.

[0053] Specific surface area of ​​500-800 cm² 3 By providing a C layer (3A) with a density of 20% / g and a mesopore volume ratio of 20-29.9%, the filtration capacity of organochlorine compounds can be improved. From the viewpoint of further improving the filtration capacity of organochlorine compounds, the specific surface area of ​​the C layer (3A) is more preferably 600-750 cm². 3 / g, more preferably 600-700 cm 3 The concentration is / g. Furthermore, the mesopore volume ratio of layer C (3A) is more preferably 23 to 29.9%, and even more preferably 25 to 29.9%, from the viewpoint of further improving the filtration capacity of organochlorine compounds. Furthermore, the micropore volume ratio (pore volume with a pore diameter of 2 nm or less) of layer C (3A) is more preferably 70.1 to 80%, more preferably 70.1 to 77%, and even more preferably 70.1 to 75%, from the viewpoint of further improving the filtration capacity of organochlorine compounds. Furthermore, the total pore volume of layer C (3A) is more preferably 0.2 to 0.6 cm³ from the viewpoint of further improving the filtration capacity of organochlorine compounds. 3 / g, more preferably 0.3 to 0.5 cm 3 It is / g.

[0054] The specific surface area of ​​the activated carbon contained in layer C (3A) is not particularly limited as long as layer C (3A) satisfies the above specific surface area, but for example, 1000 to 3000 m 2 The amount is / g, preferably 1000 to 2500m 2 / g, more preferably 1000 to 2000m2 The value is / g. Furthermore, in order to make the mesopore volume ratio of the C layer (3A) within the above range, it is preferable to use activated carbon with a relatively small mesopore volume, and examples of such activated carbon include fibrous activated carbon W-10 manufactured by Adore Co., Ltd.

[0055] Specific surface area of ​​800-1200 cm² 3 By providing an F layer (3B) with a density of fluorine / g and a mesopore volume ratio of 30-40%, the filtration capacity of fluorine-containing organic compounds (perfluoroalkyl compounds and polyfluoroalkyl compounds, hereinafter also referred to as "PFAS") can be improved. From the viewpoint of further improving the filtration capacity of PFAS, the specific surface area of ​​the F layer (3B) is more preferably 900-1100 cm². 3 / g, more preferably 1000-1100 cm 3 The value is / g. Furthermore, the mesopore volume ratio of layer F (3B) is more preferably 32-38%, and even more preferably 33-37%, from the viewpoint of further improving the filtration capacity of PFAS. Furthermore, the micropore volume ratio of layer F (3B) is more preferably 60-70%, and more preferably 62-68%, from the viewpoint of further improving the filtration capacity of PFAS. Furthermore, the total pore volume of layer F (3B) is more preferably 0.5-1.0 cm³ from the viewpoint of further improving the filtration capacity of PFAS. 3 / g, more preferably 0.6 to 0.8 cm 3 It is / g.

[0056] The specific surface area of ​​the activated carbon contained in layer F (3B) is not particularly limited as long as layer F (3B) satisfies the above specific surface area, but for example, 1000 to 3000 m 2 The amount is / g, preferably 1000 to 2500m 2 / g, more preferably 1000 to 2000m 2 The value is / g. Furthermore, in order to make the mesopore volume ratio of the F layer (3B) within the above range, it is preferable to use activated carbon with a relatively large mesopore volume, and examples of such activated carbon include fibrous activated carbon W-15 manufactured by Adore Co., Ltd.

[0057] In the present invention, the specific surface area of ​​the C layer (3A) and the F layer (3B) is a value calculated based on the nitrogen adsorption isotherm at 77K. Specifically, the nitrogen adsorption isotherm is created as follows: The sample to be measured is cooled to 77K (the boiling point of nitrogen), nitrogen gas is introduced, and the amount of nitrogen gas adsorbed V [cc / g] is measured by the volumetric method. At this time, the pressure P [hPa] of the introduced nitrogen gas is gradually increased, and the value obtained by dividing by the saturated vapor pressure P0 [hPa] of the nitrogen gas is taken as the relative pressure P / P0, and the amount of adsorption for each relative pressure is plotted to create a nitrogen adsorption isotherm. The amount of nitrogen gas adsorbed can be measured using a commercially available automatic gas adsorption amount measuring device (for example, product name "AUTOSORB-6" (manufactured by QUANTCHROME), etc.). In the present invention, the specific surface area is determined according to the BET method based on the nitrogen adsorption isotherm. This analysis can be performed using known means such as the analysis program attached to the above device. The specific surface area of ​​layer C (3A) and layer F (3B) can be adjusted to the above range by appropriately adjusting the specific surface area and content ratio of activated carbon, or by appropriately controlling the thickness and basis weight of the nonwoven fabric when manufacturing the nonwoven fabric.

[0058] In this invention, the pore volumes of the C layer (3A) and F layer (3B) are values ​​calculated by the QSDFT method. The QSDFT method (Quickly Cooled Solid Density Functional Theory) is an analytical technique that can calculate the pore size distribution from approximately 0.5 nm to approximately 40 nm for the analysis of geometrically and chemically irregular microporous and mesoporous carbon pore sizes. The QSDFT method clearly takes into account the effects of roughness and heterogeneity of the pore surface, thus significantly improving the accuracy of pore size distribution analysis. In this invention, nitrogen adsorption isotherms are measured and pore size distribution analysis is performed by the QSDFT method using Quantachrome's "AUTOSORB6". By applying the Calculation model N2 at 77K on carbon [slit pore, QSDFT equilibrium model] to the nitrogen desorption isotherm measured at a temperature of 77K, the pore size distribution can be calculated, thereby allowing the calculation of pore volume within a specific pore size range. For example, the mesopore volume ratio is calculated by determining the total pore volume and the mesopore volume for pores with a diameter of 2 to 50 nm, and then calculating the mesopore volume ratio (%) = (mesopore volume / total pore volume) × 100. The mesopore volume ratio and micropore volume of layer C (3A) and layer F (3B) correlate with the specific surface area described above, and can be adjusted to the aforementioned range by appropriately adjusting the specific surface area and content ratio of activated carbon, or by appropriately controlling the thickness and basis weight of the nonwoven fabric when manufacturing the nonwoven fabric.

[0059] In the second layer 3, the mass ratio of layer C (3A) to layer F (3B) (mass of layer C / mass of layer F) is not particularly limited, but is, for example, 2 to 7, and is preferably 3 to 7, more preferably 3 to 6, from the viewpoint of improving the balance between the filtration capacity of chloroform and the filtration capacity of PFAS and extending the life of the water purification filter.

[0060] The shape of the second layer 3 is not particularly limited as long as it is cylindrical, and for example, a form in which a nonwoven fabric containing at least activated carbon and lead removal agent is wound around the cavity 5 is included. Examples of the nonwoven fabric include dry nonwoven fabrics and wet nonwoven fabrics. Examples of dry nonwoven fabrics include nonwoven fabrics made of short fiber structures obtained by airlaid or carding (card web) methods, and needle-punched nonwoven fabrics which are laminated and integrated by needle punching the nonwoven fabric. Examples of wet nonwoven fabrics include nonwoven fabrics obtained by wet papermaking, in which a solution containing activated carbon and lead removal agent is mixed and sheared using equipment such as a pulper, beater, and refiner to produce a uniformly dispersed slurry, and the obtained slurry is flowed onto a wire, dewatered, and dried.

[0061] The thickness of the nonwoven fabric forming the second layer 3 (or, if the second layer 3 is composed of multiple layers, the thickness of the nonwoven fabric forming each layer) is not particularly limited, but is, for example, 0.1 to 1.0 mm, and preferably 0.2 to 0.5 mm.

[0062] The basis weight of the nonwoven fabric forming the second layer 3 (or the basis weight of the nonwoven fabric forming each layer if the second layer 3 consists of multiple layers) is not particularly limited, but for example, 40 to 100 g / m² is acceptable. 2 Preferably 50 to 90 g / m² 2 That is the case.

[0063] In the molded body 1, the thickness of the second layer 3 (or the total thickness of each layer if the second layer 3 is composed of multiple layers) is not particularly limited, but for example, it is 4 mm or more, preferably 8 to 30 mm, and more preferably 8 to 25 mm.

[0064] <Other Layers> In addition to the first layer 2 and the second layer 3, the main body 4 may also include other layers 6. Examples of other layers 6 include those containing activated carbon and lead removal material, and that are provided radially on the side from which purified water flows out to the first layer 2. The content ratio of each component such as activated carbon and lead removal material in the other layers 6 is not particularly limited. Examples of other layers 6 include those with a lower content ratio of lead removal material than the first layer 2, and specifically, those with the same configuration as the second layer 3.

[0065] <Structure and Manufacturing Method of Molded Body> In the water purification filter of the present invention, the molded body 1 is cylindrical in shape and has a main body portion 4 including a first layer 2 and a second layer 3 in the radial direction, and a cavity portion 5 located inside the main body portion 4.

[0066] The molded body 1 constituting the water purification filter of the present invention can be manufactured by a method that includes, for example, the steps of: preparing a nonwoven fabric containing a lead removal agent, which is a forming member for the first layer 2, and a nonwoven fabric containing activated carbon and a lead removal agent, which is a forming member for the second layer 3; and winding and molding the nonwoven fabrics such that the first layer 2 is provided on the side of the water purification filter from which purified water flows out in the radial direction relative to the second layer 3.

[0067] Figure 7 is a schematic diagram showing one embodiment of a method for manufacturing a molded body constituting the water purification filter of the present invention, and more specifically, a schematic diagram showing a method for manufacturing the molded body 1 shown in Figure 1. First, a nonwoven fabric 7 containing a lead removal agent, which is the forming member of the first layer 2, and a nonwoven fabric 8 containing activated carbon and a lead removal agent, which is the forming member of the second layer 3, are prepared. The manufacturing methods for these nonwoven fabrics are as described above. Next, the nonwoven fabric 8, which is the forming member of the second layer 3, is wound onto a winding core (for example, a metal or resin winding core) 9 until it reaches a predetermined thickness. Then, the nonwoven fabric 7, which is the forming member of the first layer 2, is wound onto the nonwoven fabric 8 wound on the winding core until it reaches a predetermined thickness. Finally, the nonwoven fabrics 7 and 8 are placed in a furnace and heat-treated to obtain a cylindrical intermediate molded body in which the second layer 3 and the first layer 2 are integrated with each other. The density of the intermediate molded body can be adjusted by adjusting the tension when winding the nonwoven fabric. Subsequently, the core 9 is removed from the intermediate molded body and cut to a predetermined length as needed to obtain the molded body 1 that constitutes the water purification filter of the present invention. Molded bodies 1 of the form shown in Figures 2 to 6 can also be manufactured by the same method as described above.

[0068] The dimensions and mass of the molded body constituting the water purification filter of the present invention are not particularly limited. The outer diameter of the molded body is, for example, 10 to 200 mm, preferably 30 to 150 mm. The inner diameter of the molded body is, for example, 5 to 190 mm, preferably 20 to 120 mm. The height (length in the axial direction of the cylinder) of the molded body is, for example, 10 to 300 mm, preferably 10 to 100 mm. The apparent density of the molded body is, for example, 0.1 to 0.4 g / cm³. 3 The concentration is preferably 0.2 to 0.3 g / cm³. 3 The apparent density is calculated by dividing the mass of the molded body by its volume.

[0069] <Other components that the water purification filter of the present invention may include as needed> The water purification filter of the present invention may include other components other than the molded body 1 as needed. Examples of other components include a cap to be joined to the upper and / or lower surface of the molded body 1, a cylindrical core provided on the inner surface of the molded body 1, and a cover layer provided on the outer surface of the molded body 1.

[0070] Regarding the cap, any known type can be used, such as those made of stainless steel, rubber, or resin, which can withstand long-term water flow and possess chemical and heat resistance.

[0071] As the core, known materials can be used, including cylindrical cores formed by winding fabrics such as nonwoven fabrics, woven fabrics, knitted fabrics, and felt into a roll, or cylindrical cores formed from resin, metal, or ceramic with through holes in the radial direction. Of these, cores formed by winding nonwoven fabric into a roll are preferred. The nonwoven fabric is not particularly limited, but examples include nonwoven fabrics containing heat-fusible fibers, and nonwoven fabrics containing heat-fusible short fibers are preferred. In particular, nonwoven fabrics in which heat-fusible short fibers are arranged randomly in three dimensions and the fibers intertwine and heat-fuse with each other are preferred. Examples of such nonwoven fabrics include dry-laid nonwoven fabrics, and needle-punched nonwoven fabrics are preferred. As the heat-fusible resin that forms the heat-fusible short fibers, those with a melting point of 80 to 140°C are preferred. Examples of heat-fusible resins include polyester resins such as polyethylene resin and copolymerized polyethylene terephthalate obtained by copolymerizing copolymer components such as isophthalic acid. Of these, polyester resins are preferred as heat-fusible resins from the viewpoint of relatively high hydrophilicity and better water compatibility, and polyethylene terephthalate copolymerized with isophthalic acid is more preferred. Examples of heat-fusible staple fibers include a fully melted type composed of only a single heat-fusible resin, or a core-sheath type heat-fusible staple fiber in which a heat-fusible resin is arranged in the sheath part and a synthetic resin component whose melting point is preferably 20°C or more, more preferably 30°C or more, higher than the melting point of the sheath part in the core part. Of these, core-sheath type heat-fusible staple fibers are preferred from the viewpoint of further increasing the strength of the water purification filter. The core component of the core-sheath type heat-fusible staple fiber is not particularly limited, but examples include a synthetic resin component whose melting point is 150 to 300°C, more preferably 200 to 300°C, and whose melting point is 20°C or more higher than the melting point of the sheath part. A specific example of the above-mentioned synthetic resin component is polyethylene terephthalate.

[0072] The cover layer is not particularly limited, but examples include fabrics such as woven fabrics, knitted fabrics, and nonwoven fabrics, with nonwoven fabrics being preferred. Nonwoven fabrics include those containing the aforementioned heat-fusible resin, and those containing the aforementioned heat-fusible fibers are preferred. Examples of nonwoven fabric forms include spunbond nonwoven fabrics. Examples of long fibers or continuous fibers constituting the spunbond nonwoven fabric include core-sheath type heat-fusible fibers in which a heat-fusible component is arranged in the sheath portion and a synthetic resin component in the core portion whose melting point is preferably 20°C or more, more preferably 30°C or more, higher than the melting point of the heat-fusible component in the sheath portion. Examples of the core component of the core-sheath type heat-fusible fiber include a synthetic resin component with a melting point of 150 to 300°C, more preferably 200 to 300°C, and whose melting point is 20°C or more higher than the melting point of the heat-fusible component in the sheath portion, and more specifically, polyethylene terephthalate. The heat-fusible component of the sheath portion of the core-sheath type heat-fusible fiber preferably has a melting point of 80 to 170°C, more preferably 80 to 140°C. More specifically, examples include olefin resins such as polypropylene and polyethylene, and polyester resins such as copolymerized polyethylene terephthalate obtained by copolymerizing copolymer components such as isophthalic acid. Of these, polyolefin resins are preferred, and polyethylene is more preferred, from the viewpoint of superior flexibility and heat-fusibility to molded articles, as well as superior handling and processability.

[0073] <Physical Properties of the Water Purification Filter> (Soluble Lead Filtration Capacity) In the water purification filter of the present invention, the dissolved lead filtration capacity per unit volume of the water purification filter, as measured by the following method, is preferably 3 to 20 L / cm³. 3 More preferably 3.5 to 15 L / cm³ 3 More preferably 3.5 to 10 L / cm³ 3 That is the case.

[0074] (Measurement Method) Tap water, to which the total organic carbon (TOC) has been reduced to 0.5 ppm or less using a commercially available activated carbon filter and hollow fiber membrane, is prepared by adding sodium hydroxide and calcium carbonate to adjust the pH to 6.5 ± 0.25, the temperature to 20 ± 2.5°C, and the hardness to 10-30 ppm. Lead nitrate (Pb(NO3)2) is then added to obtain raw water with a lead concentration of 150 ± 15 ppb. Here, TOC is measured using a TOC meter (organic matter concentration converted to carbon (C)), pH is measured using a pH meter, hardness is measured using a hardness meter, and lead concentration is measured using a lead sensor. After sealing both ends of the water purification filter with silicone sealant, the water purification filter is packed into a stainless steel housing, and raw water is passed through at an empty tower velocity of 78.5 / h, allowing the filtered water to pass radially. The total volume of filtered water until the lead concentration of the filtered water reaches 5 ppb is determined, and this is defined as the dissolved lead filtration capacity (L) of the water purification filter. Then, the obtained dissolved lead filtration capacity (L) is measured by the volume (cm³) of the molded body. 3 The value obtained by dividing by ) is the dissolved lead filtration capacity per unit volume of the water filter (L / cm³). 3 )

[0075] (Chloroform filtration capacity) In the water purification filter of the present invention, the chloroform filtration capacity per unit volume of the water purification filter, as measured by the following method, is preferably 1.5 to 10 L / cm³. 3 More preferably 2 to 5 L / cm³ 3 More preferably 2 to 3 L / cm² 3 More preferably 2 to 2.5 L / cm³ 3 That is the case.

[0076] (Measurement Method) Tap water, to which the total organic carbon (TOC) has been reduced to 0.5 ppm or less using a commercially available activated carbon filter and hollow fiber membrane, is prepared by adding sodium hydroxide and tannic acid to adjust the pH to 7.5 ± 0.5, the temperature to 20 ± 2.5°C, and the total organic carbon (TOC) to 1.0 to 2.0 ppm. Chloroform is then added to obtain raw water at a chloroform concentration of 300 ± 30 ppb. Here, TOC is measured using a TOC meter (organic matter concentration converted to carbon (C)), and pH is measured using a pH meter. The chloroform concentration is measured by gas chromatography under the following conditions. Measurement device: 7890B GC System (manufactured by Agilent Technologies) Column: GC capillary column SPB-Octyl Column temperature: 150°C Carrier gas: He (flow rate 5.2 ml / min) Detector: ECD Then, after sealing both ends of the water purification filter with silicone sealant, the water purification filter was packed into a stainless steel housing and raw water was tested at an empty column velocity of 67.3 h -1 Water is passed through the filter, allowing the filtered water to pass radially. The total volume of filtered water until the chloroform concentration in the filtered water reaches 15 ppb is determined, and this is defined as the chloroform filtration capacity (L) of the water purification filter. The obtained chloroform filtration capacity (L) is then measured against the volume (cm³) of the molded body. 3 The value obtained by dividing by ) is the chloroform filtration capacity per unit volume of the water filter (L / cm³). 3 )

[0077] (PFAS filtration capacity) In the water purification filter of the present invention, the PFAS filtration capacity per unit volume of the water purification filter, as measured by the following method, is preferably 1.5 to 10 L / cm³. 3 More preferably 2.1 to 5 L / cm³ 3 More preferably 2.1 to 3 L / cm² 3 More preferably 2.1 to 2.5 L / cm³ 3 That is the case.

[0078] (Measurement Method) Measurements will be performed in accordance with NSF / ANSI 53-2022 (DRINKING WATER TREATMENT UNITS - HEALTH EFFECTS, a standard by NSF International, based in Michigan, USA). Tap water, to which the total organic carbon (TOC) (organic matter concentration converted to carbon (C) as measured by a TOC meter) has been reduced to 0.5 mg / L or less using a commercially available activated carbon filter and hollow fiber membrane, is to be supplemented with perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) so that the concentration of PFOA is 0.0005 ± 0.00005 mg / L and the concentration of PFOS is 0.001 ± 0.00010 mg / L to obtain adjusted raw water (pH = 7.5 ± 0.5, temperature 20 ± 2.5°C, sulfate ions 200 ± 40 mg / L, chloride ions 100 ± 20 mg / L, alkalinity 200 ± 40 mg / L, turbidity less than 1 NTU). After sealing both ends of the water filter with silicone sealant, the water filter is packed into a stainless steel housing, and the raw water is filtered at a flow rate of 0.2 L / min (empty tower velocity 67.3 h). -1 The water is passed through the water purification filter radially, and the concentrations of PFOS and PFOA before and after passing through the filter are quantitatively measured by solid-phase extraction liquid chromatography-mass spectrometry (measured in accordance with the Ministry of Health, Labour and Welfare's "Inspection Methods for Water Quality Management Target Setting Items (Health Water Notification No. 1010001, dated October 10, 2003), Target 31: Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA)"). The breakthrough point is defined as the point at which the total water concentration of PFOS and PFOA in the effluent (water that has passed through the filter) becomes 0.00002 mg / L, and the total amount of filtered water (L) up to the breakthrough point is determined and defined as the PFAS filtration capacity (L) of the water purification filter. The obtained PFAS filtration capacity (L) is then measured by the volume (cm³) of the molded body. 3 The value obtained by dividing by ) is the PFAS filtration capacity per unit volume of the water filter (L / cm³). 3 )

[0079] <Applications of the Water Purification Filter> The water purification filter of the present invention can be used, for example, as a water purification filter for removing dissolved lead contained in water to be treated, or as a water purification filter for removing dissolved lead, organochlorine compounds (e.g., chloroform, dichloroethylene, trichloroethylene, tetrachloroethylene, and total trihalomethanes), and PFAS (e.g., PFOA, PFOS, perfluorohexanesulfonic acid (PFHxS), perfluorocarboxylic acids (PFCAs), perfluorohexanoic acid (PFHxA), and perfluorobutanesulfonic acid (PFBS)) contained in water to be treated. Examples of water to be treated include tap water, factory wastewater, and domestic wastewater, with tap water being preferred.

[0080] The present invention will be described in detail below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

[0081] [Experimental Example 1: Test of Filtration Capacity for Dissolved Lead] <Example 1> 1. Nonwoven fabric X forming the first layer 1-1. Raw materials for nonwoven fabric X The following raw materials were prepared to manufacture nonwoven fabric X. ・Activated carbon A: Fibrous activated carbon (manufactured by Adore Co., Ltd., product name "A-7", specific surface area 850 m²) 2 / g, total pore volume 0.35 cm³ 3 / g, micropore volume ratio 96%, mesopore volume ratio 4% • Lead removal material: Ion exchange fiber (manufactured by Unitika Ltd., product name: A-02CA, polyacrylate-based weakly acidic cation exchange fiber (Ca-substituted polyacrylate-based ion exchange fiber)) • Core-sheath type heat-sealable fiber (product name: Melty® 4080, core-sheath type heat-sealable fiber with PET core and low-melting-point polyester sheath with a melting point of 110°C)

[0082] 1-2. Manufacturing of Nonwoven Fabric X 5% by mass of activated carbon A, 70% by mass of lead removal agent, and 25% by mass of core-sheath type heat-fusible fiber were mixed, and the resulting mixture was carded to form a thin web. The resulting web was subjected to needle punching, heat-treated at an ambient temperature of 90°C, and cooled to obtain nonwoven fabric X, which is a needle-punched nonwoven fabric. The thickness of nonwoven fabric X is 0.4 mm, and the basis weight is 70 g / m². 2 That was the case.

[0083] 2. Nonwoven fabric YC forming the second layer 2-1. Raw materials for nonwoven fabric YC The following raw materials were prepared to manufacture nonwoven fabric YC. ・Activated carbon B: Fibrous activated carbon (manufactured by Adore Co., Ltd., product name "W-10W", specific surface area 1100 m²) 2 / g, total pore volume 0.65 cm³ 3 / g, micropore volume ratio 72%, mesopore volume ratio 28% • Activated carbon C: Silver-containing fibrous activated carbon (manufactured by Adore Co., Ltd., product name "J-15", specific surface area 1717 m²) 2 / g, total pore volume 0.80 cm³ 3 / g, micropore volume ratio 89%, mesopore volume ratio 11%, silver concentration 0.2% by mass) ・Lead removal material: Ion exchange fiber (manufactured by Unitika Ltd., product name: A-02CA, polyacrylate-based weakly acidic cation exchange fiber (Ca-substituted polyacrylate-based ion exchange fiber)) ・Core-sheath type heat-fusible fiber (product name: Melty® 4080, core-sheath type heat-fusible fiber with PET core and low-melting-point polyester sheath with melting point of 110°C) ・Fibrillated fiber (manufactured by Nippon Exlan Industries Co., Ltd., product name "Bipal"®, fibrillated fiber made of acrylic fiber)

[0084] 2-2. Manufacturing of Nonwoven Fabric YC A slurry was obtained by uniformly mixing 75% by mass of activated carbon B, 3% by mass of activated carbon C, 10% by mass of lead removal agent, 6% by mass of core-sheath type heat-fusible fiber, and 6% by mass of fibrillated fiber using a pulper. The obtained slurry was flowed onto a wire at a predetermined flow rate to produce a sheet, and its basis weight was adjusted by dewatering. The sheet was then dried in the dryer section after passing through the press section, and the sheet surface was smoothed in the calender section before being wound onto a reel. The sheet was then hot-pressed at 110°C with a hot press roller to obtain nonwoven fabric YC, which is a wet-process papermaking nonwoven fabric. The thickness of nonwoven fabric YC is 0.38 mm and its basis weight is 90 g / m². 2 That was the case.

[0085] 3. Manufacturing of the water purification filter A cylindrical iron pipe with an outer diameter of 47.5 mm and an axial length of 1200 mm was used as the core. Then, the nonwoven fabric YC, which will form the second layer, was wound onto the cylindrical pipe under tension to achieve a predetermined thickness and mass. After that, the nonwoven fabric X, which will form the first layer, was wound over the wound nonwoven fabric YC under tension to achieve a predetermined thickness and mass so that it overlapped tightly with the nonwoven fabric YC, thereby obtaining a wound body. The obtained wound body was placed in a furnace and heat-treated at an ambient temperature of 150°C for 1 hour, and then cooled. After that, the cylindrical pipe was removed from the wound body and cut with a cutting machine to a height of 30 mm in the height direction to obtain an in-out type water purification filter with the laminated structure shown in Figure 1. The physical properties of the obtained water purification filter are shown in Table 1.

[0086] <Comparative Example 1> 1. Nonwoven fabric X and nonwoven fabric YC Nonwoven fabric X and nonwoven fabric YC prepared in Example 1 were used.

[0087] 2. Manufacturing of the water purification filter A cylindrical iron pipe with an outer diameter of 47.5 mm and an axial length of 1200 mm was used as the core. Nonwoven fabric X was then wound onto the cylindrical pipe under tension to achieve a predetermined thickness and mass. Subsequently, nonwoven fabric YC was wound over the wound nonwoven fabric X under tension to achieve a predetermined thickness and mass, so as to closely overlap with nonwoven fabric X, to obtain a wound body. The obtained wound body was placed in a furnace and heat-treated at an ambient temperature of 150°C for 1 hour, and then cooled. After that, the cylindrical pipe was removed from the wound body and cut with a cutting machine to a height of 30 mm in the height direction to obtain an in-out type water purification filter. The physical properties of the obtained water purification filter are shown in Table 1.

[0088]

[0089] In the water purification filter of Example 1, the first layer is provided radially on the side from which purified water flows out to the second layer, and the first layer has a higher lead removal material content than the second layer, thus exhibiting superior dissolved lead filtration capacity.

[0090] On the other hand, the water purification filter of Comparative Example 1 had a first layer located on the side where raw water flows into the second layer in the radial direction, and therefore had inferior dissolved lead filtration capacity compared to Example 1.

[0091] [Experimental Example 2: Tests of chloroform filtration capacity, PFAS filtration capacity, and filtration flow rate] <Example 2> 1. Nonwoven fabric X forming the first layer The nonwoven fabric X prepared in Example 1 was used.

[0092] 2. Nonwoven fabrics YC and YF forming the second layer (C layer + F layer) 2-1. Nonwoven fabric YC forming the C layer Nonwoven fabric YC prepared in Example 1 was used.

[0093] 2-2. Nonwoven fabric YF that forms the F layer 2-2-1. Raw materials for nonwoven fabric YF The following raw materials were prepared to manufacture nonwoven fabric YF. ・Activated carbon D: Fibrous activated carbon (manufactured by Adore Co., Ltd., product name "W-15W", specific surface area 1300 m²) 2 / g, total pore volume 1.10 cm³ 3 / g, micropore volume ratio 52%, mesopore volume ratio 48% • Activated carbon E: Fibrous activated carbon (manufactured by Adore Co., Ltd., product name "H-15", specific surface area 1811 m²) 2 / g, total pore volume 0.88 cm³ 3 / g, micropore volume ratio 88%, mesopore volume ratio 12% • Activated carbon F: Fibrous activated carbon (manufactured by Adore Co., Ltd., product name "A-20", specific surface area 2000 m²) 2 / g, total pore volume 1.10 cm³ 3 / g, micropore volume ratio 78%, mesopore volume ratio 22% • Activated carbon C: Silver-containing fibrous activated carbon (manufactured by Adore Co., Ltd., product name "J-15", specific surface area 1717 m²) 2 / g, total pore volume 0.80 cm³ 3 / g, micropore volume ratio 89%, mesopore volume ratio 11%, silver concentration 0.2% by mass) ・Lead removal material: Ion exchange fiber (manufactured by Unitika Ltd., product name: A-02CA, polyacrylate-based weakly acidic cation exchange fiber (Ca-substituted polyacrylate-based ion exchange fiber)) ・Core-sheath type heat-fusible fiber (product name: Melty® 4080, core-sheath type heat-fusible fiber with PET core and low-melting-point polyester sheath with melting point of 110°C) ・Fibrillated fiber (manufactured by Nippon Exlan Industries Co., Ltd., product name "Bipal"®, fibrillated fiber made of acrylic fiber)

[0094] 2-2-2. Manufacturing of Nonwoven Fabric YF A slurry was obtained by uniformly mixing 42% by mass of activated carbon D, 21% by mass of activated carbon E, 10% by mass of activated carbon F, 3% by mass of activated carbon C, 10% by mass of lead removal agent, 7% by mass of core-sheath type heat-fusible fiber, and 7% by mass of fibrillated fiber using a pulper. The obtained slurry was flowed onto a wire at a predetermined flow rate to produce a sheet, and its basis weight was adjusted by dewatering. After that, the sheet was dried in the dryer section after passing through the press section, the sheet surface was smoothed in the calender section, and then wound onto a reel. After that, the sheet was hot-pressed at 110°C with a hot press roller to obtain nonwoven fabric YF, which is a wet-process papermaking nonwoven fabric. The thickness of nonwoven fabric YF is 0.50 mm and the basis weight is 90 g / m². 2 That was the case.

[0095] 3. Manufacturing of the water purification filter A cylindrical iron pipe with an outer diameter of 34.3 mm and an axial length of 1200 mm was used as the core. Nonwoven fabric YF, which will form part of the second layer, was wound onto the cylindrical pipe under tension to achieve a predetermined thickness and mass. Then, nonwoven fabric YC, which will form part of the second layer, was wound over the wound nonwoven fabric YF under tension to achieve a predetermined thickness and mass, so as to fit snugly with nonwoven fabric YF. Then, nonwoven fabric X, which will form the first layer, was wound over the wound nonwoven fabric YC under tension to achieve a predetermined thickness and mass, so as to fit snugly with nonwoven fabric YC, to obtain a wound body. The obtained wound body was placed in a furnace and heat-treated at an ambient temperature of 150°C for 1 hour, and then cooled. After that, the cylindrical pipe was removed from the wound body and cut with a cutting machine to a height of 30 mm in the height direction to obtain an in-out type water purification filter with the laminated structure shown in Figure 2. Table 2 shows the physical properties of the obtained water purification filter.

[0096] <Examples 3 and 4> An in-out type water purification filter with a laminated structure as shown in Figure 2 was obtained using the same method as in Example 2, except that nonwoven fabrics YF, YC, and X were wound to the thickness and mass shown in Table 2. The physical properties of the obtained water purification filters are shown in Table 2.

[0097] <Example 5> A cylindrical iron pipe with an outer diameter of 34.3 mm and an axial length of 1200 mm was used as the core. Nonwoven fabric YC, which will form part of the second layer, was wound onto the cylindrical pipe under tension to achieve a predetermined thickness and mass. Then, nonwoven fabric YF, which will form part of the second layer, was wound over the wound nonwoven fabric YC under tension to achieve a predetermined thickness and mass, so as to fit snugly with nonwoven fabric YC. Then, nonwoven fabric X, which will form the first layer, was wound over the wound nonwoven fabric YF under tension to achieve a predetermined thickness and mass, so as to fit snugly with nonwoven fabric YF, to obtain a wound body. The obtained wound body was placed in a furnace and heat-treated at an ambient temperature of 150°C for 1 hour, and then cooled. After that, the cylindrical pipe was removed from the wound body and cut with a cutting machine to a height of 30 mm in the height direction to obtain an in-out type water purification filter with the laminated structure shown in Figure 2. Table 2 shows the physical properties of the obtained water purification filter.

[0098] <Measurement and Evaluation Method> 1. Specific surface area (m²) of activated carbon 2 ( / g), total pore volume (m 3 The pore properties of activated carbon were measured using a nitrogen adsorption isotherm at 77K with a Quantachrome "AUTOSORB-1-MP". The specific surface area of ​​the activated carbon was calculated from a measurement point with a relative pressure of 0.1 using the BET method. The total pore volume, micropore volume, and mesopore volume of the activated carbon were analyzed by applying the calculation model N2 at 77K on carbon [slit pore, QSDFT equilibrium model] to the measured nitrogen desorption isotherm to calculate the pore size distribution. From the obtained total pore volume, micropore volume, and mesopore volume, the micropore volume ratio and mesopore volume ratio were calculated.

[0099] 2. Thickness of the nonwoven fabric (μm) The thickness of the nonwoven fabric was measured at three arbitrary points using a thickness gauge, and the average of the thicknesses of these three points was taken as the thickness of the nonwoven fabric.

[0100] 3. Basis weight of nonwoven fabric (g / m²) 2 The basis weight of the nonwoven fabric was measured in accordance with Method A (JIS method) of 8.3.2 "Mass per unit area under standard conditions" of JIS L 1096:2010 (Test methods for woven and knitted fabrics).

[0101] 4. Thickness of each layer (μm) The thickness of each layer was measured at any two points using calipers, and the average of the thicknesses of these two points was taken as the thickness of each layer.

[0102] 5. Mass of each layer (g) The mass of each nonwoven fabric layer was measured using an electronic balance after it was wound up.

[0103] 6. Dissolved Lead Filtration Capacity: Tap water, to which the total organic carbon (TOC) was reduced to 0.5 ppm or less using a commercially available activated carbon filter and hollow fiber membrane, was prepared by adding sodium hydroxide and calcium carbonate to achieve a pH of 6.5 ± 0.25, a temperature of 20 ± 2.5°C, and a hardness of 10 to 30 ppm. Lead nitrate (Pb(NO3)2, manufactured by Kanto Chemical Co., Ltd.) was then added to obtain raw water with a lead concentration of 150 ± 15 ppb. Here, TOC was measured using a TOC meter (Shimadzu Corporation, TOC-5000, organic matter concentration converted to carbon (C)), pH was measured using a pH meter (YOKOGAWA Corporation, pH meter PH71), hardness was measured using a hardness tester (HANNA Corporation, HI96735), and lead concentration was measured using a lead sensor (Kemio Corporation, portable lead analyzer). The lead concentration of the raw water was 150 ppb. Then, after sealing both ends of the water filter with silicone sealant, the water filter was packed into a stainless steel housing. Raw water was then passed through the water filter at a rate of 0.2 L / min (empty tower velocity 78.5 / h) radially outward from the cavity, and filtered water was discharged from the outer circumference of the cylinder. The total volume of filtered water until the lead concentration reached 5 ppb was determined, and this was defined as the dissolved lead filtration capacity (L) of the water filter. The obtained dissolved lead filtration capacity (L) was then measured against the volume (cm³) of the water filter. 3 The value obtained by dividing by ) is the dissolved lead filtration capacity per unit volume of the water filter (L / cm³). 3 )

[0104] 7. Specific surface area, total pore volume, micropore volume fraction, and mesopore volume fraction of layers C and F constituting the second layer. 0.1 g of each layer was cut from the obtained water purification filter and used as a measurement sample. The collected measurement samples were measured using a Quantachrome "AUTOSORB-6" to obtain a nitrogen adsorption isotherm at 77 K. The specific surface area was calculated from the measurement point with a relative pressure of 0.1 using the BET method. The total pore volume, micropore volume, and mesopore volume were analyzed by applying the calculation model N2 at 77K on carbon [slit pore, QSDFT equilibrium model] to the measured nitrogen desorption isotherm to calculate the pore size distribution. Specifically, the pore volume in each pore size range listed in Table 2 is a value obtained by reading the graph showing the pore size distribution or by calculating it from the reading.

[0105] 8. Chloroform Filtration Capacity: Tap water, to which the total organic carbon (TOC) was reduced to 0.5 ppm or less using a commercially available activated carbon filter and hollow fiber membrane, was prepared by adding sodium hydroxide and tannic acid to adjust the pH to 7.5 ± 0.5, the temperature to 20 ± 2.5°C, and the total organic carbon (TOC) to 1.0 to 2.0 ppm. Chloroform (manufactured by Nacalai Tesque) was then added to obtain raw water at a chloroform concentration of 300 ± 30 ppb. Here, TOC was measured using a TOC meter (Shimadzu Corporation, TOC-5000, organic matter concentration converted to carbon (C)), and pH was measured using a pH meter (YOKOGAWA Corporation, pH meter PH71). The chloroform concentration was measured by gas chromatography under the following conditions. The chloroform concentration of the raw water was 323 ppb. Measurement device: 7890B GC System (manufactured by Agilent Technologies) Column: GC capillary column SPB-Octyl Column temperature: 150°C Carrier gas: He (flow rate 5.2 ml / min) Detector: ECD Then, after sealing both ends of the water purification filter with silicone sealant, the water purification filter was packed into a stainless steel housing, and raw water was added at 0.2 L / min (empty column velocity 67.3 h) -1Water was passed through the cavity of the water filter radially outward, and the filtered water was discharged from the outer circumference of the cylinder. The total volume of filtered water until the chloroform concentration of the filtered water reached 15 ppb was determined, and this was defined as the chloroform filtration capacity (L) of the water filter. The obtained chloroform filtration capacity (L) was then measured against the volume (cm³) of the water filter. 3 The value obtained by dividing by ) is the chloroform filtration capacity per unit volume of the water filter (L / cm³). 3 )

[0106] 9. PFAS filtration capacity was measured in accordance with NSF / ANSI 53-2022 (DRINKING WATER TEATMENT UNITS-HEALTH EFFECTS, a standard established by NSF International, based in Michigan, USA). Tap water, to which the total organic carbon (TOC) (organic matter concentration converted to carbon (C), measured with a TOC meter (Shimadzu Corporation, TOC-5000)) was reduced to 0.5 mg / L or less using a commercially available activated carbon filter and hollow fiber membrane, was to be treated with perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) so that the concentration of PFOA was 0.0005 ± 0.00005 mg / L and the concentration of PFOS was 0.001 ± 0.00010 mg / L to obtain adjusted raw water (pH = 7.5 ± 0.5, temperature 20 ± 2.5°C, sulfate ions 200 ± 40 mg / L, chloride ions 100 ± 20 mg / L, alkalinity 200 ± 40 mg / L, turbidity less than 1 NTU). After sealing both ends of the water filter with silicone sealant, the water filter is packed into a stainless steel housing, and the raw water is filtered at a flow rate of 0.2 L / min (empty tower velocity 67.3 h). -1Water was passed radially outward from the cavity of the water purification filter, and the filtered water was discharged from the outer circumference of the cylinder. The concentrations of PFOS and PFOA before and after passing through the filter were quantitatively measured by solid-phase extraction liquid chromatography-mass spectrometry (measured in accordance with the Ministry of Health, Labour and Welfare's "Inspection Methods for Water Quality Management Target Setting Items (Health Water Notification No. 1010001, dated October 10, 2003), Target 31 Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA)"). The breakthrough point was defined as the point at which the total water concentration of PFOS and PFOA in the discharged water (water that has passed through the filter) reached 0.00002 mg / L, and the total amount of filtered water (L) up to the breakthrough point was calculated and defined as the PFAS filtration capacity (L) of the water purification filter. The obtained PFAS filtration capacity (L) was then measured against the volume (cm³) of the water purification filter. 3 The value obtained by dividing by ) is the PFAS filtration capacity per unit volume of the water filter (L / cm³). 3 )

[0107] 10. The end cap was attached to the water purification filter using hot melt adhesive and installed in the reservoir tank. Then, the reservoir tank was filled to capacity with water and all the water was passed through the water purification filter. The reservoir tank was filled to capacity again and the water flow operation was repeated two more times. After that, 1 liter of water was added to the reservoir tank again and passed through, and the time (min) until 1 liter of water was gone was measured and the filtration flow rate (L / min) per minute was calculated.

[0108]

[0109] The water purification filters of Examples 2 to 5 demonstrated excellent filtration capabilities for chloroform and PFAS.

[0110] 1. Molded body 2. First layer 3. Second layer 3A C layer 3B F layer 4. Main body 5. Cavity 6. Other layers 7. Nonwoven fabric forming the first layer 8. Nonwoven fabric forming the second layer 9. Core

Claims

1. A water purification filter comprising a cylindrical molded body, wherein the molded body has, in the radial direction, a main body portion comprising a first layer and a second layer, and a cavity portion located inside the main body portion, the first layer containing a lead removal material, the second layer containing activated carbon and a lead removal material, the first layer being provided on the side from which purified water flows out relative to the second layer in the radial direction, and the first layer having a higher lead removal material content than the second layer.

2. The water filter according to claim 1, wherein the first layer further contains activated carbon.

3. The second layer contains activated carbon and lead removal material, and has a specific surface area of ​​500 to 800 cm². 3 The C layer has a density of 1 / g and a mesopore volume ratio of 20-29.9%, and contains activated carbon and lead removal material, with a specific surface area of ​​800-1200 cm². 3 A water purification filter according to claim 1 or 2, comprising an F layer having a density of / g and a mesopore volume ratio of 30 to 40%.

4. A filtration method for obtaining filtered water by passing raw water through a water purification filter according to any one of claims 1 to 3.

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