JP2018167223A - Filter cartridge and filter - Google Patents

Abstract

To provide a filter cartridge and a filter having a high efficiency of adsorbing and removing metals.SOLUTION: A filter cartridge is formed by laminating plural kinds of ground fabrics for filtration or winding them around a hollow inner cylinder. The ground fabrics for filtration are a nonwoven fabric obtained by chemically bonding metal adsorbing groups to polyolefin fibers, and includes a nonwoven fabric layer (A) 17a positioned on the downstream side and a nonwoven fabric layer (B) 17b positioned on the upstream side. The nonwoven fabric layer A is composed of polyolefin fibers chemically bonded with sulfonic acid groups as the metal adsorbing groups, The nonwoven fabric layer B is composed of polyolefin fibers chemically bonded with at least one selected as the metal adsorbing groups from amino groups, N-methyl-D-glucamine groups, iminodiacetic acid groups, iminodiethanol groups, amidoxime groups, phosphoric acid groups, carboxylic acid groups, and ethylenediamine triacetate groups.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a filter cartridge and a filter in which a nonwoven fabric is laminated or wound.

  In recent years, with the progress of semiconductor manufacturing technology in the electronic industry, the design dimensions of the wiring pitch of integrated circuits have been reduced to a few tens of nanometers. With the miniaturization of integrated circuits, the operating speed tends to increase and the power consumption decreases. In the manufacturing process of an integrated circuit, metal impurities contained in a chemical solution cause a short circuit of a wiring or a decrease in current value, resulting in a decrease in yield, so that the chemical solution needs to be highly purified. Distillation and ion exchange resins are used as means for removing such metal impurities. However, distillation is expensive, and ion exchange resins have problems such as slow processing speed and contamination by eluate. doing. Conventionally, a depth type cartridge filter for adsorbing and removing a metal in a solution is known. Patent Document 1 proposes to use a melt blown nonwoven fabric wrapped around a hollow pipe having a hole. A part of the present applicants proposed a cartridge filter in which a nonwoven fabric composed of fibers grafted with ion exchange groups and a nonwoven fabric composed of fibers grafted non-grafted in Patent Document 2 were proposed. Yes.

Japanese National Patent Publication No. 11-504853 JP 2009-090259 A

  However, the conventional filter does not have a high metal adsorption removal efficiency, and this improvement is required.

  The present invention provides a filter cartridge and a filter having a high metal adsorption removal efficiency in order to solve the conventional problems.

  The filter cartridge of the present invention is a filter cartridge in which a plurality of types of filtering base fabrics are laminated or wound around a hollow inner cylinder, and the filtering base fabric is a nonwoven fabric in which metal adsorption groups are chemically bonded to polyolefin fibers. The filtration base fabric includes a non-woven fabric layer A located on the downstream side and a non-woven fabric layer B located on the upstream side, and the non-woven fabric layer A is composed of polyolefin fibers chemically bonded with sulfonic acid groups as metal adsorption groups. The non-woven fabric layer B has amino groups, N-methyl-D-glucamine groups, iminodiacetic acid groups (iminodiacetic acid groups), iminodiethanol groups, amidoxime groups, phosphoric acid groups, carboxylic acid groups, and ethylenediamine as metal adsorbing groups. It is composed of a polyolefin fiber chemically bonded with at least one selected from acetic acid groups.

  The filter of the present invention is a filter having a filtration part in which a plurality of types of filtration base fabrics are laminated or wound around a hollow inner cylinder, and the filtration base fabric is a nonwoven fabric in which metal adsorption groups are chemically bonded to polyolefin fibers. The filtration base fabric includes a non-woven fabric layer A located on the downstream side and a non-woven fabric layer B located on the upstream side, and the non-woven fabric layer A is a polyolefin fiber chemically bonded with a sulfonic acid group as a metal adsorbing group. The nonwoven fabric layer B is composed of an amino group, N-methyl-D-glucamine group, iminodiacetic acid group (iminodiacetic acid group), iminodiethanol group, amidoxime group, phosphoric acid group, carboxylic acid group and It is characterized by comprising polyolefin fibers chemically bonded with at least one selected from ethylenediaminetriacetic acid groups.

  According to the present invention, the filter cartridge is a laminated or wound type, and includes a nonwoven fabric layer A located on the downstream side and a nonwoven fabric layer B located on the upstream side, and the nonwoven fabric layer A includes a sulfone group as a metal adsorption group. The nonwoven fabric layer B is composed of chemically bonded polyolefin fibers, and the nonwoven fabric layer B has amino groups, N-methyl-D-glucamine groups, iminodiacetic acid groups (iminodiacetic acid groups), iminodiethanol groups, amidoxime groups, phosphoric acid as metal adsorbing groups. By comprising a polyolefin fiber in which at least one selected from a group, a carboxylic acid group and an ethylenediaminetriacetic acid group is chemically bonded, a base fabric for filtration with high metal adsorption removal efficiency can be obtained.

FIG. 1 is a schematic partial cutaway view of a filter cartridge according to an embodiment of the present invention. FIG. 2 is a schematic explanatory view of a processing apparatus incorporating a depth type cartridge filter. FIG. 3 is a schematic explanatory view of a liquid passing test apparatus according to an embodiment of the present invention. FIG. 4 is a graph showing the removal performance with respect to K of the filters of Example 1 and Comparative Example 1. FIG. 5 is a graph showing the removal performance of the filters of Comparative Examples 2 and 3 with respect to K. FIG. 6 is a graph showing the removal performance of the filters of Example 2 and Comparative Example 4 with respect to Cu. FIG. 7 is a graph showing the removal performance of the filters of Comparative Examples 5 and 6 with respect to Cu. FIG. 8 is a graph showing the removal performance of the filters of Example 3 and Comparative Example 7 with respect to Na. FIG. 9 is a graph showing the removal performance of the filters of Comparative Examples 8 and 9 with respect to Na.

  The present invention is a filter cartridge in which a plurality of types of filtration base fabrics are laminated or wound around a hollow inner cylinder, wherein the filtration base fabric is a nonwoven fabric in which metal adsorption groups are chemically bonded to polyolefin fibers, and the filtration The base fabric includes a nonwoven fabric layer A located on the downstream side and a nonwoven fabric layer B located on the upstream side. If it winds in this order, it is arbitrary to wind other types of nonwoven fabrics further. The nonwoven fabric layer A is composed of polyolefin fibers chemically bonded with sulfone groups as metal adsorption groups, and the nonwoven fabric layer B is composed of amino groups, N-methyl-D-glucamine groups, iminodiacetic acid groups as metal adsorption groups. (Iminodiacetic acid group), iminodiethanol group, amidoxime group, phosphoric acid group, carboxylic acid group and at least one selected from ethylenediaminetriacetic acid groups are used to form polyolefin fibers. Thereby, a metal can be removed efficiently. In addition, what combined the different types of base fabric for filtration into the single base fabric for filtration is also contained in the multiple types of base fabric for filtration.

  In the present invention, the nonwoven fabric layer B is particularly preferably composed of polyolefin fibers chemically bonded with iminodiethanol groups. This is because the metal removal efficiency is high. As for metals that can be adsorbed, sulfonic acid groups mainly adsorb Na, Cu, and K, and iminodiethanol groups mainly adsorb Cr, Al, and Fe.

The polyolefin fibers constituting the nonwoven fabrics A and B are preferably long fibers. This is because the long-fiber non-woven fabric hardly generates fiber waste and has high filter performance. Among them, a melt blown long fiber nonwoven fabric having a high mass per unit area (weight per unit area) of 10 to 100 g / m ² is preferable.

  It is preferable that the single fiber average diameter of the polyolefin fiber which comprises the said nonwoven fabrics A and B is 0.2-10 micrometers. If it is the said range, filter performance is high. In addition, since the surface area (specific surface area) can be increased and the surface of the base material for the graft polymerization reaction can be increased, the graft ratio can be increased.

  The polyolefin fiber is preferably one selected from polypropylene, a copolymer of propylene and ethylene, polyethylene, or a copolymer of ethylene and another α-olefin having 4 or more carbon atoms, and high-density polyethylene is particularly preferable. These polymers are inert, stable against chemicals, and can be grafted.

  The filter cartridge is a filter cartridge including a hollow inner cylinder and a filtering base fabric, and the filtering base fabric is a nonwoven fabric in which metal adsorption groups are chemically bonded to polyolefin fibers, and the filtering base fabric is: A filter cartridge that forms a laminated structure by being wound around the hollow inner cylinder is preferable.

  The filter of the present invention is a filter incorporating the filter cartridge. The filter cartridge is housed in a container around a base fabric for filtration wrapped around an inner cylinder. When the filter cartridge is incorporated into the filter container, the filter cartridge is incorporated into the filter in a state where the filter cartridge is accommodated in the container. In the case of a cartridge type filter, the filter function can be regenerated by exchanging only the filter cartridge. Is included. In the case of a capsule type filter, the part corresponding to the filter cartridge is a filtration part.

  Next, a method for chemically bonding various functional groups to the polyolefin fiber will be described. After irradiating the polyolefin fiber with radiation such as electron beam or gamma ray, the polyolefin fiber is brought into contact with an emulsion liquid containing a reactive monomer such as GMA, or after contacting the polyolefin fiber with an emulsion liquid containing a reactive monomer, an electron beam. The reactive monomer is graft polymerized to the polyolefin fiber by irradiation with radiation such as γ-ray. In the case of irradiation with an electron beam, an irradiation dose of 1 to 200 kGy, preferably 5 to 100 kGy, more preferably 10 to 50 kGy may be achieved. Irradiation is preferably performed under a nitrogen atmosphere. A commercially available electron beam irradiation apparatus can be used. For example, as an area beam type electron beam irradiation apparatus, EC250 / 15 / 180L (manufactured by Iwasaki Electric Co., Ltd.), EC300 / 165/800 (Iwasaki Electric Co., Ltd.) And EPS300 (manufactured by NHV Corporation) can be used.

  Specific examples of the graft polymerization method include a liquid phase graft polymerization method. After the nonwoven fabric is activated by irradiation with radiation such as γ rays or electron beams, water, a surfactant and a reactive monomer are used. In the non-woven fabric substrate, the graft polymerization is completed, and then the graft chain formed on the substrate has sulfonic acid groups, amino groups, N-methyl-D-glucamine groups, Functional functional groups such as an iminodiacetic acid group (iminodiacetic acid group), iminodiethanol group, amidoxime group, phosphoric acid group, carboxylic acid group, and ethylenediaminetriacetic acid group, that is, ion exchange groups and / or chelate groups are introduced. In the present invention, the method is not particularly limited to the liquid phase graft polymerization method. The gas phase graft polymerization method in which the substrate is brought into contact with the vapor of the monomer to perform polymerization, the substrate is immersed in the monomer solution, and then taken out from the monomer solution. An impregnation gas phase graft polymerization method in which the reaction is performed in a gas phase can also be used. As chemical formulas of typical functional functional groups, (Chemical Formula 1) is a sulfonic acid group (SC group), (Chemical Formula 2) is an iminodiethanol group (IDE group), (Chemical Formula 3) is an iminodiacetic acid group (IDA group), ( An N-methyl-D-glucamine group (NMDG group) is shown in Chemical formula 4).

  However, R in (Chemical Formula 1) to (Chemical Formula 4) is polyethylene (PE) + GMA (Chemical Formula 5) or polypropylene (PP) + GMA (Chemical Formula 6).

  However, n and m in the above (Chemical Formula 5) to (Chemical Formula 6) are integers of 1 or more.

  Table 1 summarizes the characteristics of the functional functional groups of (Chemical Formula 1) to (Chemical Formula 4) of the present invention.

  This will be described below with reference to the drawings. In the following drawings, the same symbols indicate the same items. FIG. 1 is a schematic partial cutaway view of a filter cartridge in a depth type cartridge filter according to an embodiment of the present invention. The filter cartridge 1 is used by winding at least two layers of a filter base fabric around a hollow inner cylinder (hollow pipe with a hole). The nonwoven fabric layer (A) 3 located on the downstream side and the nonwoven fabric layer (B) 4 located on the upstream side are laminated.

  FIG. 2 is a schematic explanatory view of the depth type cartridge filter. The depth type cartridge filter 5 has end caps 9 a and 9 b attached to the depth type filter cartridge 10, incorporated into the filter container 6, supplied with water to be treated from the supply port 7, and from the outside to the inside of the filter cartridge 10. To-be-treated water passes, during which the metal is removed and taken out from the treated water outlet 8.

  FIG. 3 is a schematic explanatory view of a liquid passing test apparatus according to an embodiment of the present invention. This liquid flow test apparatus 11 supplies treated water 13 contained in a container 12 from a fluororesin (PFA) tube 14 and a tube pump 15 to a laminated filter 17 through a column 16, adsorbs and removes metal, and treats water. 19 is placed in a container 18. The multilayer filter 17 includes a nonwoven fabric layer (A) 17a located on the downstream side and a nonwoven fabric layer (B) 17b located on the upstream side. 3 is a column-type laminated filter, but the basic structure is the same as that of a wound filter. Therefore, the test result of the winding filter can be regarded as the same as that of the column-type stacked type.

  The present invention will be specifically described below with reference to examples. In addition, this invention is not limited to the following Example.

<Graft ratio>
The graft ratio was calculated from the mass of the nonwoven fabric before and after grafting according to the following formula.
Graft rate (%) = 100 × (BA) / A
(In the formula, A represents the mass of the nonwoven fabric substrate before grafting, and B represents the mass of the nonwoven fabric substrate after grafting.)
<Elemental analysis>
The metal concentration in the sampled sample was measured using atomic absorption spectrometry, which can quantify trace elements. From the obtained metal concentration, the metal removal rate (%) was determined by the following formula (Equation 1). Blank solution in the formula indicates the metal concentration in the prepared metal solution.

(Equation 1)
Metal removal rate (%) = [(Blank liquid metal concentration-Metal concentration in liquid after passing through filter) / Blank liquid metal concentration] x 100

<Sulfonic acid group introduction method>
(Electron beam irradiation process and graft chain introduction process)
An electron beam is irradiated with an acceleration voltage of 200 kV in a nitrogen atmosphere on one side of a melt blown nonwoven fabric (weight per unit of mass 81 g / m ² , thickness 0.38 mm, fiber filling rate 24%) of a high-density polyethylene material having an average fiber diameter of 6 μm. Irradiation was performed at a dose of 50 kGy. Next, the melt-blown nonwoven fabric after irradiation was preliminarily prepared and immersed in a monomer solution in an emulsion state in which nitrogen substitution (nitrogen bubbling) was performed, and emulsion graft polymerization was performed for 4 hours while maintaining at 55 ° C.
The monomer solution used was a pure water emulsion solution containing 1.6% by mass of glycidyl methacrylate (GMA) and 0.2% by mass of Tween 20 (manufactured by Nacalai Tesque) as a surfactant, based on the total weight of the solution.
When the graft ratio was evaluated, the GMA graft ratio was 50%.
(Sulphonic acid group introduction step)
The GMA graft-polymerized non-woven fabric obtained above was immersed in a sodium sulfite solution having a concentration of 10% by mass prepared by dissolving sodium sulfite in isopropanol: 15% by mass / pure water: 85% by mass, and heated at 80 ° C. for 9 hours. Then, sulfonic acid groups were introduced. The nonwoven fabric was taken out, washed with pure water, and dried to obtain a sulfonic acid type nonwoven fabric.
The sulfonic acid type non-woven fabric obtained above was immersed in 1N sulfuric acid and heated at 80 ° C. for 2 hours to open the remaining epoxy groups and replace sodium ions with hydrogen ions. The nonwoven fabric was taken out, washed with pure water, and dried to obtain a sulfonic acid type ion exchange nonwoven fabric having an ion exchange capacity of 2 meq / g. The nonwoven fabric had a thickness of 0.82 mm.

<Iminodiethanol group introduction process>
(Electron beam irradiation process and graft chain introduction process)
An electron beam irradiation step and a graft chain introduction step were performed in the same manner as for the sulfonic acid group. When the graft ratio was evaluated, the GMA graft ratio was 50%.
(Iminodiethanol group introduction process)
The GMA graft-polymerized non-woven fabric obtained above was immersed in an iminodiethanol solution having a concentration of 20% by mass prepared by dissolving iminodiethanol in pure water, and heated at 80 ° C. for 4 hours to introduce iminodiethanol groups. . The nonwoven fabric was taken out, washed with pure water, and dried to obtain an iminodiethanol type nonwoven fabric having an ion exchange capacity of 2.0 meq / g. The nonwoven fabric had a thickness of 0.75 mm.

<Iminodiacetic acid group introduction step>
(Electron beam irradiation process and graft chain introduction process)
An electron beam irradiation step and a graft chain introduction step were performed in the same manner as for the sulfonic acid group. When the graft ratio was evaluated, the GMA graft ratio was 50%.
(Iminodiacetic acid group introduction step)
The GMA graft-polymerized nonwoven fabric obtained above was prepared by dissolving iminodiacetic acid disodium hydrate in Levelan LV-8: 17% by mass / pure water: 71% by mass. The GMA graft-polymerized nonwoven fabric obtained above was immersed in the product solution and heated at 80 ° C. for 9 hours to introduce iminodiacetic acid groups.
The iminodiacetic acid-type nonwoven fabric obtained above was immersed in hydrochloric acid having a concentration of 6N, and sodium ions were replaced with hydrogen ions. The nonwoven fabric was taken out, washed with pure water, and dried to obtain an iminodic acid type ion exchange nonwoven fabric having an ion exchange capacity of 0.8 meq / g. The nonwoven fabric had a thickness of 0.68 mm.
<Production of metal removal filter>
The multilayer filter 17 shown in FIG. 3 was used. That is, it is comprised by the nonwoven fabric layer (A) 17a located in the downstream, and the nonwoven fabric layer (B) 17b located in the upstream. Cut the two types of non-woven fabric substrates into a diameter of 7mmΦ, and stack 10 layers in total in a 7mmΦ column made of PFA (copolymer of tetrafluoroethylene and perfluoroalkyl vinyl ether). Two types of functional group composite type filters 17 were produced.
A sulfonic Sanmotozai (hereinafter, described as SC _K) as nonwoven layer A and, iminodiethanol substrate as the non-woven fabric layer B (hereinafter referred to as IDE _Cr) was used. SC _K adsorbs potassium (K), IDE _Cr is chromic acid (hereinafter, chromium (Cr) and described) to adsorb. The substrate weight (g / sheet) is as follows.
SC substrate = 0.0059 (g / sheet)
IDE base material = 0.0053 (g / sheet)
IDA base material = 0.0055 (g / sheet)

(Example 1, Comparative Example 1)
<Preparation of metal solution>
A potassium nichromate standard solution (1000 ppm), a special reagent manufactured by Nacalai Tesque, was diluted with ultrapure water to prepare a 1000 ppb metal solution (Cr = 1000 ppb, K = 2000 ppb).
<Liquid passing and sampling>
As shown in FIG. 3, using a tube pump, a metal solution (potassium dichromate) was passed through the filter at 3.1 mL / min, and the solution after passing through the substrate was sampled into a 100 mL PFA bottle.
In this example and comparative example, the metal removal performance for K was examined.
FIG. 4 shows the metal removal rate of the functional group composite filter of (SC _K → IDE _Cr ) and (IDE _Cr → SC _K ). From this result, when removing K in a solution system in which K and Cr coexist, rather than removing K with an SC alone group, Cr is removed beforehand with an IDE group, and then K is removed with SC (IDE). _Cr → SC _K ) was found to show a higher removal rate.

(Comparative Examples 2-3)
Experiments were conducted in the same manner as in Example 1 except that a sulfonic acid base material (SC _K ) was used as the nonwoven fabric layer and an iminodiethanol base material (IDE _Cr ) was used as the nonwoven fabric layer. This metal removal rate is shown in FIG. SC _K is able to remove the K but, IDE _Cr not be removed. These single filter value of the combined functional group composite filter plus the metal removal rate (hereinafter, described as the theoretical value), showed comparable values and SC _K.

(Example 2, Comparative Example 4)
In this example and comparative example, metal removal performance for Cu was examined. The filter structure was the same as in Example 1.
<Preparation of metal solution>
A sodium (Na) standard solution (1000 ppm) and a copper (Cu) standard solution (1000 ppm), which are special reagents manufactured by Nacalai Tesque, diluted with ultrapure water, and a 1000 ppb metal solution (Na = 1000 ppb, Cu = 1000 ppb) Was prepared.
<Liquid passing and sampling>
A metal solution (Na, Cu) was passed at the same flow rate as in Example 1 and sampled.
<Results of metal removal rate>
FIG. 6 shows the metal removal rate of the functional group composite filter of (SC _{Na, Cu} → IDA _Cu ) and (IDA _Cu → SC _{Na, Cu} ). From this result, when removing Cu in a solution system in which Na and Cu are mixed, it was found that combining IDA and SC shows a higher removal rate than removing Cu with IDA and SC single groups. . In addition, regarding the order of IDA and SC, it was found that the order of IDA _Cu → SC _{Na, Cu} shows a higher removal rate.

(Comparative Examples 5-6)
FIG. 7 shows the metal removal rates of two types of single filters (SC _{Na, Cu} ) and (IDA _Cu ). _Cu can be removed by IDA _Cu and SC _{Na, Cu} . Further, the value of the functional group composite filter (hereinafter referred to as the theoretical value) obtained by adding the metal removal rates of these single filters is SC _{Na, Cu} + IDA _Cu .

(Example 3, Comparative Example 7)
In this example, metal removal performance for Na was examined.
FIG. 8 shows the metal removal rate of the functional group composite filter of (SC _{Na, Cu} → IDA _Cu ) and (IDA _Cu → SC _{Na, Cu} ). From this result, when removing Na in a solution system in which Na and Cu are mixed, rather than removing Na with an SC single group, Cu is removed beforehand with an IDA group, and then Na is removed with SC (IDA). _Cu → SC _{Na, Cu} ) showed a higher removal rate than the theoretical value.

(Comparative Example 8, Comparative Example 9)
FIG. 9 shows the metal removal rates of two types of single filters (SC _{Na, Cu} ) and (IDA _Cu ). SC _{Na and Cu} can remove _Na, but IDA _Cu cannot. The reason why the SC _{Na, Cu} metal removal rate shows a negative value from the middle is that Na is released by the adsorption of Cu, which has higher adsorption power, by the functional group that adsorbed Na. is there. In addition, the value of the functional group composite filter (hereinafter referred to as the theoretical value) obtained by adding the metal removal rates of these single filters was equivalent to SC _{Na, Cu} .

  Considering the above examples and comparative examples, as a result of investigating the influence of the stacking order of the base material in the functional group composite filter, the metal that is not the target of adsorption of the functional group is reduced and then the metal that is the target of adsorption is adsorbed. It was found that the metal removal performance is improved when the stacking order is set. One presumption is that the contact probability between the functional group and the target metal increases as the number of metals that are not the target of adsorption decreases with respect to the metal that is the target of functional group adsorption.

  The filter cartridge of the present invention is useful for a depth type cartridge filter in which a nonwoven fabric is wound in a cylindrical shape.

1,10 Depth type filter cartridge 2 Hollow inner cylinder (hollow pipe with holes)
3, 17a Non-woven fabric layer located on the downstream side (A)
4, 17b Non-woven fabric layer (B) located upstream
5 Depth Type Cartridge Filter 6 Filter Container 7 Supply Port 8 Treated Water Extraction Ports 9a, 9b End Cap 11 Liquid Flow Test Equipment 12, 18 Container 13 Water to be Treated 14 Fluororesin (PFA) Tube 15 Tube Pump 16 Column 17 Multilayer Filter 19 Treated water

Claims (6)

A filter cartridge in which a plurality of types of filter base fabrics are laminated or wound around a hollow inner cylinder,
The base fabric for filtration is a nonwoven fabric in which metal adsorption groups are chemically bonded to polyolefin fibers,
The base fabric for filtration includes a nonwoven fabric layer A located on the downstream side and a nonwoven fabric layer B located on the upstream side,
The nonwoven fabric layer A is composed of polyolefin fibers chemically bonded with sulfonic acid groups as metal adsorption groups,
The non-woven fabric layer B has amino groups, N-methyl-D-glucamine groups, iminodiacetic acid groups (iminodiacetic acid groups), iminodiethanol groups, amidoxime groups, phosphoric acid groups, carboxylic acid groups, and ethylenediaminetriacetic acid as metal adsorbing groups. A filter cartridge comprising a polyolefin fiber chemically bonded with at least one selected from a group.   2. The filter cartridge according to claim 1, wherein the nonwoven fabric layer B is composed of polyolefin fibers chemically bonded to iminodiethanol groups.   The filter cartridge according to claim 1 or 2, wherein the polyolefin fibers constituting the nonwoven fabrics A and B are long fibers.   The filter cartridge according to any one of claims 1 to 3, wherein a single fiber average diameter of the polyolefin fibers constituting the nonwoven fabrics A and B is 0.2 to 10 µm.   A filter incorporating the filter cartridge according to claim 1. A filter having a filtration part in which a plurality of types of filtration base fabrics are laminated or wound around a hollow inner cylinder,
The base fabric for filtration is a nonwoven fabric in which metal adsorption groups are chemically bonded to polyolefin fibers,
The base fabric for filtration includes a nonwoven fabric layer A located on the downstream side and a nonwoven fabric layer B located on the upstream side,
The nonwoven fabric layer A is composed of polyolefin fibers chemically bonded with sulfonic acid groups as metal adsorption groups,
The non-woven fabric layer B has amino groups, N-methyl-D-glucamine groups, iminodiacetic acid groups (iminodiacetic acid groups), iminodiethanol groups, amidoxime groups, phosphoric acid groups, carboxylic acid groups, and ethylenediaminetriacetic acid as metal adsorbing groups. A filter comprising a polyolefin fiber chemically bonded with at least one selected from a group.

Images