Method for changing ionic form of anion exchanger, and method for producing anion exchanger

Abstract

This invention provides a method for easily and quickly changing the ionic form of an anion exchanger at a high rate while suppressing the residue of various metals. A method for changing the ionic form of an anion exchanger is characterized in that, in order to change the ionic form of the anion exchanger, the anion exchanger is contacted with an aqueous solution of quaternary ammonium hydroxide. Preferably, the quaternary ammonium hydroxide is selected from one or more compounds represented by the general formula [R1R2R3R4N+]OH-(I) (where R1 to R4 may also be hydrocarbon groups with 1 to 4 carbon atoms having a hydroxyl group, and these groups may be the same or different).

Description

Technical Field

[0001] This invention relates to a method for changing the ionic form of anion exchangers and a method for manufacturing anion exchangers. Prior Technology

[0002] In the past, anion exchangers were used to remove metal ions mixed in ultrapure water or in various alcohol or ether solutions.

[0003] For example, ultrapure water used in semiconductor manufacturing processes is purified to a high purity in a purification device called a subsystem (see, for example, Patent Document 1 (Japanese Patent Application Publication No. 2010-234356)). However, during the delivery of the solution from the subsystem to the various points of use (wet stations) where semiconductor manufacturing processes are carried out, impurities such as metallic components sometimes dissolve from the piping or valves. Furthermore, various alcohols or ethers used in cleaning agents and dissolving solvents sometimes also leach impurities such as metallic components from the solution storage tank or delivery piping.

[0004] Therefore, when the impurities mentioned above are anionic, it is considered to place a refining column containing anion exchangers near each point of use to remove the impurities.

[0005] Furthermore, the ultrapure water supplied to the point of use for cleaning in the aforementioned semiconductor manufacturing process can be recycled and reused again as part of the raw water for ultrapure water production.

[0006] However, in the aforementioned semiconductor manufacturing process, considering the possibility that ionic impurities or particles such as element B and element As may leach from the constituent materials (semiconductor materials) of the processed material into the ultrapure water, it is believed that the recovered ultrapure water system contains a large amount of ionic impurities or particles. Therefore, in reusing recycled ultrapure water, it is required to remove ionic impurities or particulates mixed in with the ultrapure water beforehand.

[0007] Regarding the method of removing ionic impurities or particles from the aforementioned recovered ultrapure water, the applicant has previously proposed a method for purifying ultrapure water using an ion exchanger filling module filled with monolithic organic porous anion exchangers (see Patent Document 1 (WO2019 / 221187)).

[0008] As mentioned above, some have proposed using anion exchangers to remove ionic impurities or particles from ultrapure water or pharmaceutical solutions, and have requested the preparation of anion exchangers suitable for the purification of ultrapure water, or the regeneration of anion exchangers used for the purification of ultrapure water for reuse after use.

[0009] On the other hand, in the production of ultrapure water used in semiconductor manufacturing processes or pharmaceutical manufacturing processes, it is also important to control the content of trace ionic impurities in the final ultrapure water or the process water in the ultrapure water production steps.

[0010] As mentioned above, the ultrapure water used in semiconductor manufacturing processes is purified to a high purity in a purification system known as a subsystem. During the delivery of this solution from the subsystem to the various points of use (wet processing equipment) in semiconductor manufacturing, impurities such as metallic components sometimes leach out from piping or valves. Furthermore, impurities such as metallic components sometimes also leach out from chemical storage tanks or delivery piping for various alcohols or ethers. The aforementioned metallic components are not fixed in terms of type or form. It is believed that, in addition to ions, they also exist in the form of particles in a condensed or dispersed state.

[0011] Regarding methods for determining the concentration of ionic impurities in water, some have proposed using the aforementioned monolithic organic porous anion exchanger to capture metallic impurities in ultrapure water, and then dissolving and recovering the captured metallic impurities to determine the metallic impurities (see Patent Document 1 (WO2019 / 221187)).

[0012] Furthermore, as a method for determining the concentration of ionic impurities in water, there is a method that involves passing the analyte water through an ion exchanger such as a porous membrane or ion exchange resin with ion exchange function, and then dissolving the captured ionic impurities in a dissolution solution and measuring the concentration of ionic impurities in the recovered dissolution solution (concentration method). For example, Patent Document 2 (Japanese Patent Application Publication No. 5-45351) discloses an analytical method using a concentration method with a porous membrane having ion exchange function.

[0013] As mentioned above, in order to analyze the content of ionic impurities in ultrapure water or pharmaceutical solutions, some people have proposed using anion exchangers, requiring the preparation of anion exchangers suitable for the above analysis, or the regeneration of anion exchangers used for the above analysis after use for reuse. [Previous Technical Documents] [Patent Literature]

[0014] Patent Document 1: Specification No. WO2019 / 221187 Patent Document 2: Japanese Patent Application Publication No. 5-45351 Summary of the Invention

[0015] [The problem that the invention aims to solve]

[0016] In anion exchangers with quaternary ammonium or amine groups as anion exchange groups, the ionic form (the relative ionic form of the anion exchange group) is preferably OH-form in order to improve the capture performance of impurity elements. Therefore, it is required that the ionic form be OH-formed during the preparation of anion exchangers or that the ionic form be regenerated to OH-form during the regeneration of the ionic form of anion exchangers. In order to change the ionic form of anion exchanger to OH form, the treatment is usually carried out in the following order: (1) acid treatment, (2) water treatment, (3) hydrochloric acid treatment, (4) water treatment, (5) carbonate or bicarbonate treatment, (6) water treatment and (7) sodium hydroxide treatment. That is, after acid cleaning of the anion exchanger, the relative ions of the anion exchanger are sequentially converted into chloride ions and carbonate ions, and then treated to become hydroxide ions. By performing the treatment in this order, the ionic form can be changed to the OH form at a high ratio.

[0017] However, the above-mentioned methods for changing the ionic form involve many steps, long processing time, or are labor-intensive. There is a need for a simpler and faster method to change the ionic form to the OH form. Furthermore, the above-mentioned methods of changing the ionic form may result in various metals that are impurities in carbonates or bicarbonates being mixed in during the above-mentioned "(5) carbonate or bicarbonate treatment" remaining in the anion exchanger, or sodium remaining in the anion exchanger during the above-mentioned "(7) sodium hydroxide treatment". Therefore, after the above-mentioned "(7) sodium hydroxide" treatment, a longer water treatment is required, or a cation exchanger needs to be configured downstream of the anion exchanger to remove metal leaching (metal ions) during use.

[0018] Under such circumstances, the object of the present invention is to provide a method for easily and quickly changing the ionic form of anion exchanger at a high rate while suppressing the residue of various metals, and a method for manufacturing anion exchangers.

[0019] As a result of in-depth research in order to achieve the above-mentioned objective, the inventors discovered that by contacting the anion exchanger with an aqueous solution of quaternary ammonium hydroxide, the above-mentioned technical problem could be solved in order to change the ionic form of the anion exchanger. Based on this discovery, the present invention was completed.

[0020] That is, the present invention provides: (1) A method for changing the ionic form of an anion exchanger, characterized in that, in order to change the ionic form of the anion exchanger, the anion exchanger is brought into contact with an aqueous solution of quaternary ammonium hydroxide. (2) The method for changing the ionic form of anion exchanger as in (1), wherein the quaternary ammonium hydroxide is selected from one or more compounds represented by the following general formula (I): [Chemistry 1] (In the formula, R1 to R4 can each have a hydrocarbon group with 1 to 4 carbon atoms of the hydroxyl group, and they can be the same or different from each other.) (3) The method for changing the ionic form of anion exchanger as described in (1), wherein the concentration of the quaternary ammonium hydroxide in the aqueous solution of the quaternary ammonium hydroxide is 0.1~2.0N. (4) The method for changing the ionic form of anion exchanger as in (1), wherein the anion exchanger is contacted with an inorganic acid, then washed with water, and then contacted with an aqueous solution of the quaternary ammonium hydroxide. (5) The method for changing the ionic form of anion exchanger as in (1), wherein the anion exchanger is contacted with an inorganic acid, then washed with water, then contacted with hydrochloric acid, then washed with water, and then contacted with an aqueous solution of the quaternary ammonium hydroxide. (6) The method for changing the ionic form of anion exchanger as in (1), wherein the anion exchange system is a monolithic organic porous anion exchanger. (7) The method for changing the ionic form of anion exchanger as described in (6), wherein the monolithic organic porous anion exchange system comprises a continuous structure, the continuous structure being composed of: a three-dimensionally continuous framework with an average fineness of 1-60 μm in the dry state, consisting of an aromatic vinyl polymer containing 0.1-5.0 mol% of cross-linked structural units in all constituent units, and three-dimensionally continuous pores with an average diameter of 10-200 μm in the dry state between the frameworks, the total pore volume in the dry state being 0.5-10 mL / g, having anion exchange groups, and an anion exchange capacity per unit volume in the water-wet state being 0.2-1.0 mg equivalents / mL (water-wet state), and the anion exchange groups being uniformly distributed in the organic porous anion exchanger. (8) The method for changing the ionic form of anion exchanger as described in (6), wherein, for the anion exchanger, an aqueous solution of quaternary ammonium hydroxide is passed through the solution at a liquid space velocity (SV) of 20,000 h⁻¹ or less. (9) The method for changing the ionic form of anion exchanger as in (1), wherein, in order to change the ionic form of anion exchanger used in the purification of ultrapure water or the purification of pharmaceutical solutions, or in order to change the ionic form of anion exchanger used in the analysis of anionic impurities in ultrapure water or pharmaceutical solutions, the anion exchanger is brought into contact with an aqueous solution of quaternary ammonium hydroxide. (10) A method for manufacturing an anion exchanger, characterized in that, in order to change the ionic form of the anion exchanger, the anion exchanger is contacted with an aqueous solution of quaternary ammonium hydroxide, and... (11) In the manufacturing method of the anion exchanger as in (10), in order to change the ionic form of the anion exchanger used in the purification of ultrapure water or the purification of pharmaceutical solutions, or in order to change the ionic form of the anion exchanger used in the analysis of anionic impurities in ultrapure water or pharmaceutical solutions, the anion exchanger is brought into contact with an aqueous solution of quaternary ammonium hydroxide. [Effects of the Invention]

[0021] According to the present invention, a method for easily and quickly changing the ionic form of anion exchanger at a high rate while suppressing the residue of various metals, and a method for manufacturing anion exchangers are provided. Simple Explanation of the Diagram

[0022] [Figure 1] SEM image of a morphological example of a monolithic organic porous anion exchanger. [Figure 2] Schematic diagram of the co-continuous structure of a monolithic organic porous anion exchanger. [Figure 3] SEM image of a morphological example of a monolithic organic porous intermediate. [Figure 4] is a diagram illustrating an example of the contact morphology between the anion exchanger and an aqueous solution of quaternary ammonium hydroxide in this invention. [Figure 5](a) and (b) show a purification apparatus U having a container A containing anion exchangers and a container C containing cation exchangers. [Figure 6] is a graph showing the results of embodiments and comparative examples of the present invention. Implementation

[0023] First, the method for changing the ionic form of the anion exchanger in this invention will be described. The method for changing the ionic form of anion exchanger in this invention is characterized in that, in order to change the ionic form of the anion exchanger, the anion exchanger is brought into contact with an aqueous solution of quaternary ammonium hydroxide.

[0024] <Anion Exchanger> In this invention, the anion exchange system refers to an ion exchanger with anion exchange capability. As an anion exchanger, it can be selected from monolithic organic porous anion exchangers, anion exchange resins, etc., and is preferably a monolithic organic porous anion exchanger.

[0025] <Monolithic Porous Organic Anion Exchanger> In this invention, the anion exchanger is a monolithic organic porous anion exchanger, and there is no particular limitation on the case of monolithic organic porous anion exchangers.

[0026] A monolithic organic porous anion exchange system is a porous body in which anion exchange groups are introduced into a monolithic organic porous body. The monolithic organic porous body of the monolithic organic porous anion exchange system is a porous body with a framework formed by an organic polymer and multiple interconnecting pores within the framework that serve as flow channels for the reaction liquid. The monolithic organic porous anion exchange system is a porous body in which anion exchange groups are introduced into the framework of the monolithic organic porous body and uniformly distributed therein. Furthermore, in this specification, "monolithic organic porous material" is also referred to as "monolithic", "monolithic organic porous anion exchanger" is also referred to as "monolithic anion exchanger", "monolithic organic porous cation exchanger" is also referred to as "monolithic cation exchanger", and "monolithic organic porous intermediate" which is an intermediate (precursor to monolithic material) in the manufacture of monolithic material is also referred to as "monolithic intermediate".

[0027] In this invention, the monolithic anion exchange system obtained by introducing anion exchange groups in a monolithic form should preferably be an organic porous body composed of a continuous framework phase and a continuous porous phase, with the thickness of the continuous framework being 1~100μm, the average diameter of the continuous pores being 1~1000μm, and the total micropore volume being 0.5~50mL / g.

[0028] If the thickness of the continuous skeleton of a single anion exchanger is less than 1 μm, in addition to the disadvantages such as reduced anion exchange capacity per unit volume, the mechanical strength is also reduced. Especially when the liquid is passed through at a high flow rate, the single anion exchanger is prone to large deformation, or the contact efficiency between the reaction liquid and the single anion exchanger is reduced, and the catalyst activity is easily reduced, so it is less than ideal. On the other hand, if the thickness of the continuous framework of a single anion exchanger exceeds 100 μm, the framework becomes too thick and bulky, the diffusion of the matrix becomes time-consuming, and the catalytic activity is easily reduced, which is less than ideal. Furthermore, the thickness of the aforementioned continuous skeleton was determined by SEM observation.

[0029] If the average diameter of the continuous pores in a single anion exchanger is less than 1 μm, the pressure loss during water flow is likely to be high. If the average diameter of the continuous pores in a single anion exchanger exceeds 1000 μm, the contact between the treated liquid and the single anion exchanger becomes insufficient, and the removal performance is likely to decrease. Furthermore, the average diameter of the continuous pores of a single anion exchanger in the dry state refers to the maximum value of the pore distribution curve obtained by mercury infiltration method.

[0030] If the total pore volume of a single anion exchanger is less than 0.5 mL / g, the contact efficiency of the treated liquid is likely to be low, the permeate volume per unit cross-sectional area will be small, and the throughput will be low. If the total pore volume of a single anion exchanger exceeds 50 mL / g, the anion exchange capacity per unit volume will decrease, the removal performance will likely be low, and the mechanical strength will be reduced. In particular, when the liquid is passed through at high speed, the single anion exchanger is prone to large deformation, and the pressure loss during liquid passage will likely increase rapidly. In addition, the total fine pore volume is determined by mercury injection method.

[0031] Examples of such monolithic anion exchanger structures include the continuous bubble structure disclosed in Japanese Patent Application Publication No. 2002-306976 and No. 2009-62512, the co-continuous structure disclosed in Japanese Patent Application Publication No. 2009-67982, the particle condensation structure disclosed in Japanese Patent Application Publication No. 2009-7550, and the particle composite structure disclosed in Japanese Patent Application Publication No. 2009-108294.

[0032] The anion exchange capacity per unit volume of a single anion exchanger in a water-wet state should preferably be 0.1~1.0 mg equivalents / mL (water-wet state). If the anion exchange capacity of a single anion exchanger in the dry state is less than 0.1 mg equivalent / mL, the amount of water treated until breakthrough will be smaller, and the replacement frequency of the module filled with the single anion exchanger will be more likely to increase. In addition, if the anion exchange capacity of the aforementioned single anion exchanger in the dry state exceeds 1.0 mg equivalent / mL, the pressure loss during water flow will be more likely to increase. Furthermore, the anion exchange capacity of porous materials on the surface of the framework, which are only introduced with anion exchange groups, cannot be determined uniformly, depending on the type of porous material or anion exchange group, and is at most 500 μg equivalents / g.

[0033] The anion exchange groups introduced into the monolithic anion exchanger are uniformly distributed not only on the surface of the monolith but also within its framework. "Uniformly distributed anion exchange groups" here refers to a distribution of anion exchange groups at least on the μm scale across the surface and within the framework. The distribution of anion exchange groups can be easily confirmed using EPMA. Furthermore, if the anion exchange groups are uniformly distributed not only on the surface of the monolith but also within its framework, the physical and chemical properties of the surface and interior become uniform, thus facilitating improvements in resistance to swelling and shrinkage.

[0034] Regarding the anion exchange groups introduced into a single anion exchanger, examples include quaternary ammonium groups such as trimethylammonium, triethylammonium, tributylammonium, dimethylhydroxyethylammonium, dimethylhydroxypropylammonium, and methyldihydroxyethylammonium, as well as tertiary ammonium groups, strontium groups, and phosphonium groups.

[0035] In a monolithic anion exchanger, the material constituting the continuous framework is usually an organic polymer material with a cross-linked structure. There is no particular limitation on the crosslinking density of polymer materials. However, relative to all the constituent units of the polymer material, it is advisable to contain 0.1 to 30 mol% of crosslinked structural units, preferably 0.1 to 20 mol%. If the crosslinking structural unit percentage is less than 0.1 mol%, the mechanical strength is insufficient and therefore less than ideal. On the other hand, if the crosslinking structural unit percentage exceeds 30 mol%, the introduction of anion exchange groups may become difficult, which is also less than ideal. There are no particular restrictions on the type of polymer material. Examples include aromatic vinyl polymers such as polystyrene, poly(α-methylstyrene), polyvinyl toluene, polyvinyl benzyl chloride, polyvinyl biphenyl, and polyvinyl naphthalene; polyolefins such as polyethylene and polypropylene; poly(halogenated polyolefins) such as polyvinyl chloride and polytetrafluoroethylene; nitrile polymers such as polyacrylonitrile; and crosslinked polymers such as (meth)acrylic polymers such as polymethyl methacrylate, polyoxypropylene methacrylate, and polyethyl acrylate. The above polymers can be obtained by copolymerizing a single vinyl monomer with a crosslinking agent, or by polymerizing multiple vinyl monomers with a crosslinking agent. Furthermore, they can also be obtained by blending two or more polymers. Among these organic polymer materials, considering the ease of forming a continuous structure, the ease of introducing anion exchange groups, the high degree of mechanical strength, and the high degree of stability to acids or alkalis, cross-linked polymers of aromatic vinyl polymers are preferable, especially styrene-divinylbenzene copolymers and vinylbenzyl chloride-divinylbenzene copolymers as ideal materials.

[0036] <Examples of the morphology of monolithic organic porous anion exchangers> Regarding the morphology of a monolithic organic porous anion exchanger (hereinafter appropriately referred to as monolithic anion exchanger a), it is preferable that the monolithic organic porous anion exchange system comprises: a three-dimensionally continuous framework with an average fineness of 1 to 60 μm in the dry state, consisting of an aromatic vinyl polymer containing 0.1 to 5.0 mol% of cross-linked structural units in all its constituent units, and three-dimensionally continuous pores with an average diameter of 10 to 200 μm in the dry state between the frameworks; a co-continuous structure having a total micropore volume of 0.5 to 10 mL / g in the dry state, having anion exchange groups, and an anion exchange capacity per unit volume of 0.2 to 1.0 mg equivalents / mL (in the water-wet state), and the anion exchange groups being uniformly distributed in the organic porous anion exchanger. Furthermore, the monolith (hereinafter appropriately referred to as monolith a) constituting monolithic anion exchanger a (before the introduction of the anion exchanger group) is an organic porous body, which is preferably a co-continuous structure consisting of: a three-dimensional continuous skeleton with an average fineness of 1 to 60 μm in the dry state composed of aromatic vinyl polymers containing 0.1 to 5.0 mol% of cross-linked structural units in all constituent units, and three-dimensional continuous pores with an average diameter of 10 to 200 μm in the dry state between the skeletons; and a total pore volume of 0.5 to 10 mL / g in the dry state.

[0037] The monolithic anion exchanger a is a co-continuous structure consisting of a three-dimensional continuous framework with an average diameter of 1~60μm, preferably 3~58μm in the dry state, and three-dimensional continuous pores between the framework with an average diameter of 10~200μm, preferably 15~180μm, especially preferably 20~150μm in the dry state. Figure 1 shows a SEM image of a morphological example of a monolithic anion exchanger a, and Figure 2 shows a schematic diagram of the co-continuous structure of monolithic anion exchanger a. As shown in the schematic diagram of Figure 2, the co-continuous structure consists of a continuous framework phase 1 and a continuous porous phase 2 interwoven to form a three-dimensionally continuous structure 10. Compared to previous continuous bubble-type and particle-condensed monolithic structures, this continuous porous structure 2 exhibits higher continuity and no dimensional deviation. Furthermore, the framework is thicker and thus has higher mechanical strength.

[0038] If the average diameter of the three-dimensionally continuous pores is less than 10 μm in the dry state, the treated liquid becomes difficult to diffuse, which is less than ideal. If it exceeds 200 μm, the contact between the treated liquid and the individual anion exchanger a becomes insufficient, resulting in inadequate removal performance, which is also less than ideal. Furthermore, if the average size of the framework is less than 1 μm in the dry state, the anion exchange capacity and mechanical strength become lower, which is also less than ideal. Additionally, the contact efficiency between the reaction liquid and the individual anion exchanger a decreases, leading to reduced removal performance, which is also less than ideal. On the other hand, if the size of the framework exceeds 60 μm, the framework becomes too coarse, resulting in uneven diffusion of the treated liquid, which is also less than ideal.

[0039] The average diameter of the opening of the dried monolith a, the average diameter of the opening of the dried monolith anion exchanger a, and the average diameter of the opening of the dried intermediate monolith (hereinafter appropriately referred to as monolith intermediate a) obtained in step I of the manufacturing of monolith a as described below refer to the maximum value of the pore distribution curve obtained by mercury infiltration. Furthermore, the average thickness of the skeleton of the monolith anion exchanger a in the dried state can be obtained by SEM observation of the dried monolith anion exchanger a. Specifically, at least three SEM observations of the dried monolith anion exchanger a are performed, and the thickness of the skeleton in the obtained images is measured; the average value of these is taken as the average thickness. Furthermore, the skeleton can be rod-shaped with a circular cross-section, or it can include cross-sections with different diameters, such as elliptical cross-sections. In this case, the thickness is the average of the minor axis and the major axis.

[0040] Furthermore, the total pore volume per unit weight of a single anion exchanger a in the dry state is 0.5~10 mL / g. If the total pore volume is less than 0.5 mL / g, the contact efficiency between the matrix or solvent becomes lower, which is less than ideal. Furthermore, the permeation per unit cross-sectional area decreases, and the throughput is reduced, which is also less than ideal. On the other hand, if the total pore volume exceeds 10 mL / g, the contact efficiency between the treated liquid and the single anion exchanger decreases, resulting in reduced removal performance, which is also less than ideal. If the size of the three-dimensionally continuous pores and the total pore volume are within the above range, the contact with the treated liquid is extremely uniform, and the contact area is also larger.

[0041] In a monolithic anion exchanger a, the backbone material is an aromatic vinyl polymer containing 0.1–5.0 mol%, preferably 0.5–3.0 mol%, of cross-linked structural units in all constituent units, and is hydrophobic. If the cross-linked structural units are less than 0.1 mol%, the mechanical strength is insufficient and therefore less than ideal. On the other hand, if the cross-linked structural units exceed 5 mol%, the structure of the porous body becomes prone to deviating from a cocontinuous structure. There are no particular restrictions on the types of aromatic vinyl polymers, such as polystyrene, poly(α-methylstyrene), polyvinyltoluene, polyvinylbenzyl chloride, polyvinyl biphenyl, and polyvinylnaphthalene. The above polymers can be obtained by copolymerizing one vinyl monomer with a cross-linking agent, or by polymerizing multiple vinyl monomers with a cross-linking agent. In addition, they can be obtained by blending two or more polymers. Among these organic polymer materials, considering the ease of forming a co-continuous structure, the ease of introducing anion exchange groups, the high degree of mechanical strength, and the high degree of stability to acids or bases, styrene-divinylbenzene copolymer or vinylbenzylchloro-divinylbenzene copolymer is preferable.

[0042] Regarding the anion exchange group (anion exchange group) introduced into the monolithic anion exchanger a, it can be selected from one or more of the following: trimethylammonium, triethylammonium, tributylammonium, dimethylhydroxyethylammonium, dimethylhydroxypropylammonium, methyldihydroxyethylammonium, etc., quaternary ammonium groups, or tertiary strontium, phosphonium, etc.

[0043] The anion exchange groups introduced into the monolithic anion exchanger a are not only uniformly distributed on the surface of the porous material, but also within the framework of the porous material.

[0044] Monolithic anion exchanger a has an anion exchange capacity of 0.2~1.0 mg equivalents / mL (water-wetted state) per unit volume. Monolithic anion exchanger a features highly continuous and uniform pores in three dimensions, allowing for uniform diffusion of the matrix or solvent system. Therefore, the reaction proceeds rapidly. With anion exchange capacity within the aforementioned range, high removal performance and long lifetime are achieved.

[0045] <Manufacturing Methods of Monolithic A and Monolithic Anion Exchanger A> Single block 'a' is obtained by performing the following steps: Step I involves preparing an oil-in-water droplet emulsion by stirring a mixture of oil-soluble monomers, surfactants, and water (without ion exchange groups). The oil-in-water droplet emulsion is then polymerized to obtain a monolithic organic porous intermediate (monolithic intermediate a) with a total micropore volume exceeding 16 mL / g and below 30 mL / g. Step II involves preparing a mixture comprising: an aromatic vinyl monomer, 0.3–5 moles of a crosslinking agent (containing at least two vinyl groups per molecule), an organic solvent that dissolves the aromatic vinyl monomer, an organic solvent that does not dissolve the polymer formed by the polymerization of the crosslinking agent, and a polymerization initiator. Step III involves polymerizing the mixture obtained in Step II under static conditions in the presence of the monolithic intermediate a obtained in Step I, to obtain monolith a of an organic porous material with a co-continuous structure.

[0046] In the above-mentioned method for manufacturing single block a, step I, which obtains the single block intermediate a, can be carried out in accordance with the method described in Japanese Patent Application Publication No. 2002-306976.

[0047] In other words, in step I of the manufacturing method of block a, oil-soluble monomers that do not contain ion exchange groups can be cited as examples of monomers that do not contain ion exchange groups such as carboxylic acid groups, sulfonic acid groups, tertiary amine groups, and quaternary ammonium groups, which have low water solubility and are lipophilic. Specific examples of such monomers include aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, vinylbenzyl chloride, vinyl biphenyl, and vinylnaphthalene; α-olefins such as ethylene, propylene, 1-butene, and isobutene; diene monomers such as butadiene, isoprene, and chloropentadiene; halogenated olefins such as vinyl chloride, vinyl bromide, vinylidene chloride, and tetrafluoroethylene; nitrile monomers such as acrylonitrile and methacrylonitrile; vinyl esters such as vinyl acetate and vinyl propionate; and (meth)acrylic monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, and glycidyl methacrylate. Among these monomers, aromatic vinyl monomers are particularly suitable, such as styrene, α-methylstyrene, vinyltoluene, vinylbenzyl chloride, and divinylbenzene. These monomers can be used alone or in combination of two or more. However, it is more ideal to select cross-linking monomers such as divinylbenzene and ethylene glycol dimethacrylate as one of the oil-soluble monomers, and set their content in the total oil-soluble monomers at 0.3~5 mol%, preferably 0.3~3 mol%, which is beneficial to the formation of the co-continuous structure.

[0048] Regarding the surfactants used in step I of the manufacturing method for monolithic a, there are no particular restrictions as long as they can form an oil-in-water (W / O) emulsion when mixed with water, provided they are oil-soluble monomers without anion exchange groups. Nonionic surfactants such as sorbitol monooleate, sorbitol monolaurate, sorbitol monopalmitate, sorbitol monostearate, sorbitol trioleate, polyoxyethylene nonylphenyl ether, polyoxyethylene ethyl stearyl ether, and polyoxyethylene ethyl sorbitol monooleate can be used; anionic surfactants such as potassium oleate, sodium dodecylbenzenesulfonate, and dioctyl sodium sulfosuccinate can be used; cationic surfactants such as distearate dimethyl ammonium chloride can be used; and amphoteric surfactants such as lauryl dimethyl betaine can be used. These surfactants can be used alone or in combination of two or more. Furthermore, an oil-in-water emulsion refers to an emulsion in which the oil phase is a continuous phase, with water droplets dispersed within it. Regarding the amount of surfactant added, it varies depending on the type of oil-soluble monomer and the size of the intended emulsion particles (macropores), so it cannot be generalized. It can be selected within the range of approximately 2% to 70% relative to the total amount of oil-soluble monomer and surfactant.

[0049] Furthermore, in step I of the manufacturing method for monolithic a, a polymerization initiator may be used as needed when forming an oil-water droplet emulsion. The polymerization initiator may appropriately be a compound that generates free radicals upon exposure to heat or light. Polymerization initiators can be water-soluble or oil-soluble, and examples include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), 2,2'-azobis(2-methylisobutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylpentanonitrile), dimethyl 2,2'-azobisisobutyrate, 4,4'-azobis(4-cyanopentanoic acid), 1,1'-azobis(cyclohexane-1-carboxynitrile), benzoyl peroxide, lauryl peroxide, potassium persulfate, ammonium persulfate, tetramethylthiuram disulfide, hydrogen peroxide-ferric chloride(II), sodium persulfate-sodium acid sulfite, etc.

[0050] Regarding step I of the manufacturing method for block a, there are no particular restrictions on the mixing method used to form an oil-water droplet emulsion by mixing an oil-soluble monomer without ion exchange groups, a surfactant, water, and a polymerization initiator. Methods such as mixing all components together at once, or dissolving the oil-soluble monomer, surfactant, and the oil-soluble component of the oil-soluble polymerization initiator separately and uniformly with the water-soluble component of the water-soluble polymerization initiator, and then mixing the individual components are acceptable. There are also no particular restrictions on the mixing apparatus used to form the emulsion; a conventional mixer, homogenizer, or high-pressure homogenizer can be used, as long as the apparatus is appropriate for obtaining the desired emulsion particle size. Furthermore, there are no particular restrictions on the mixing conditions; the stirring speed and stirring time can be arbitrarily set to obtain the desired emulsion particle size.

[0051] Regarding the method for manufacturing monolithic a, the monolithic intermediate a obtained in step I is an organic polymer material with a cross-linked structure, preferably an aromatic vinyl polymer. The cross-linking density of this polymer material is not particularly limited, but it is ideal to contain 0.1–5 mol% of cross-linked structural units, preferably 0.3–3 mol%, relative to all the constituent units of the polymer material. If the cross-linked structural units are less than 0.3 mol%, the mechanical strength is insufficient, which is less desirable. On the other hand, if the cross-linked structural units exceed 5 mol%, the structure of the obtained monolith is prone to deviating from a co-continuous structure, which is also less desirable. In particular, when the total pore volume is 16–20 ml / g, in order to form a co-continuous structure, the number of cross-linked structural units should preferably be less than 3 mol.

[0052] In step I of the manufacturing method for monolithic a, there are no particular restrictions on the type of polymer material of the monolithic intermediate a. Various organic polymers can be used, such as aromatic vinyl polymers like polystyrene, poly(α-methylstyrene), polyvinyl toluene, polyvinyl benzyl chloride, polyvinyl biphenyl, and polyvinyl naphthalene; polyolefins like polyethylene and polypropylene; poly(halogenated polyolefins) like polyvinyl chloride and polytetrafluoroethylene; nitrile polymers like polyacrylonitrile; and crosslinked polymers like (meth)acrylic polymers such as polymethyl methacrylate, polyoxypropylene methacrylate, and ethyl methacrylate. The aforementioned organic polymers can be polymers obtained by copolymerizing one type of vinyl monomer with a crosslinking agent, or polymers obtained by polymerizing multiple types of vinyl monomers with a crosslinking agent. Furthermore, they can be obtained by blending two or more polymers. Among these organic polymer materials, considering the ease of forming a continuous macroporous structure, the ease of introducing anion exchange groups, the high degree of mechanical strength, and the high degree of stability against acids or alkalis, crosslinked polymers of aromatic vinyl polymers are preferable. Styrene-divinylbenzene copolymers and vinylbenzyl chloride-divinylbenzene copolymers are particularly ideal materials.

[0053] In the manufacturing method of monolithic intermediate a, the total micropore volume per unit weight of the monolithic intermediate a in the dry state is greater than 16 mL / g and less than 30 mL / g, preferably greater than 16 mL / g and less than 25 mL / g. That is, the monolithic intermediate a is basically a continuous macroporous structure, but the part where the macropores overlap, i.e., the opening (mesopore), is particularly large. Therefore, the framework constituting the monolithic structure has a structure that is as close as possible to a one-dimensional rod-shaped framework from the two-dimensional wall surface. Figure 3 shows a SEM image of a morphological example of monolithic intermediate a, which has a near-rod-shaped framework. If it coexists with a polymerization system, a porous body with a co-continuous structure using the structure of monolithic intermediate a as a template is formed. If the total micropore volume is too small, the structure of the monolith obtained after the polymerization of vinyl monomers will change from a cocontinuous structure to a continuous macroporous structure, which is less than ideal. On the other hand, if the total micropore volume is too large, the mechanical strength of the monolith obtained after the polymerization of vinyl monomers will decrease, or the anion exchange capacity per unit volume will decrease when anion exchange groups are introduced, which is also less than ideal. To achieve the total micropore volume of the monolith intermediate a within the above-mentioned range, the monomer to water ratio should be approximately 1:20 to 1:40.

[0054] Furthermore, in the monolith intermediate a obtained in step I of the manufacturing method of monolith a, the average diameter of the overlapping portion of the macropores, i.e., the opening (mesopore), is 5~100 μm in the dry state. If the average diameter of the opening is less than 5 μm in the dry state, the opening diameter of the monolith obtained after the polymerization of vinyl monomers becomes smaller, and the pressure loss during fluid permeation increases, which is less than ideal. On the other hand, if it exceeds 100 μm, the opening diameter of the monolith obtained after the polymerization of vinyl monomers becomes too large, and the contact between the treated liquid and the monolith anion exchanger becomes insufficient. As a result, the removal performance will decrease, which is also less than ideal. Monolith intermediate a is preferably a uniform structure with uniform macropore size and opening diameter, but it is not limited to this structure. It can also be a uniform structure interspersed with non-uniform macropores that are larger than the uniform macropore size.

[0055] Step II of the manufacturing method for monolith a is a step of preparing a mixture as follows, which consists of an aromatic vinyl monomer, 0.3 to 5 moles of a crosslinking agent in a fully oil-soluble monomer having at least two vinyl groups in one molecule, an organic solvent that dissolves the aromatic vinyl monomer, a crosslinking agent that does not dissolve the aromatic vinyl monomer, and a polymerization initiator. Furthermore, there is no order between steps I and II; step II can be performed after step I, or step I can be performed after step II.

[0056] Regarding the aromatic vinyl monomers used in step II of the method for manufacturing monomer a, there are no particular restrictions as long as the molecule contains a polymerizable vinyl group and is a lipophilic aromatic vinyl monomer with high solubility in organic solvents. It is preferable to choose vinyl monomers that will generate polymer materials of the same type or similar to monomer intermediate a coexisting in the aforementioned polymerization system. Specific examples of such vinyl monomers include styrene, α-methylstyrene, vinyltoluene, vinylbenzyl chloride, vinyl biphenyl, and vinylnaphthalene. These monomers can be used alone or in combination of two or more. Suitable aromatic vinyl monomer systems include styrene and vinylbenzyl chloride.

[0057] The amount of aromatic vinyl monomer added in step II of the method for manufacturing monolithic intermediate a should be 5 to 50 times, preferably 5 to 40 times, by weight, relative to the monolithic intermediate a coexisting during polymerization. If the amount of aromatic vinyl monomer added is less than 5 times that of monolithic intermediate a, a thick rod-shaped framework cannot be formed. Furthermore, in the case of introducing anion exchange groups, the anion exchange capacity per unit volume decreases after the introduction of anion exchange groups, which is less than ideal. On the other hand, if the amount of aromatic vinyl monomer added exceeds 50 times, the diameter of the continuous pores becomes smaller, and the pressure loss during liquid flow increases, which is also less than ideal.

[0058] The crosslinking agent used in step II of the manufacturing method for monolith a is preferably one containing at least two polymerizable vinyl groups and having high solubility in organic solvents. Specific examples of crosslinking agents include divinylbenzene, divinylnaphthalene, divinylbiphenyl, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, and butanediol diacrylate. These crosslinking agents can be used alone or in combination of two or more. Ideally, considering both high mechanical strength and stability against hydrolysis, crosslinking agents are aromatic polyvinyl compounds such as divinylbenzene, divinylnaphthalene, and divinylbiphenyl. The amount of crosslinking agent used, relative to the total amount of vinyl monomer and crosslinking agent (fully oil-soluble monomer), is 0.3–5 mol%, especially 0.3–3 mol%. If the amount of crosslinking agent used is less than 0.3 mol%, the mechanical strength of the monolith is insufficient, which is less than ideal. On the other hand, if the amount is too high, it may be difficult to quantitatively introduce anion exchange groups, which is also less than ideal. Furthermore, it is ideal to use the aforementioned crosslinking agent in such a way that the crosslinking density of the monolithic intermediate a coexisting during the polymerization of the vinyl monomer / crosslinking agent is almost equal. If the difference in the amounts used is too large, a deviation in the crosslinking density distribution will occur in the resulting monolith. In addition, in the case of introducing anion exchange groups, the reaction of introducing anion exchange groups becomes more prone to cracking.

[0059] The organic solvent used in step II of the manufacturing method of monolith a is an organic solvent that dissolves aromatic vinyl monomers and crosslinking agents but does not dissolve the polymer formed by the polymerization of aromatic vinyl monomers. In other words, it is a poor solvent for the polymer formed by the polymerization of aromatic vinyl monomers. The organic solvent varies greatly depending on the type of aromatic vinyl monomer, so it is difficult to list general examples. For example, when the aromatic vinyl monomer is styrene, examples of organic solvents include alcohols such as methanol, ethanol, propanol, butanol, hexanol, cyclohexanol, octanol, 2-ethylhexanol, decanol, dodecyl alcohol, propylene glycol, and tetramethylene glycol; chain (poly)ethers such as diethyl ether, butyl ceroxythrene, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; chain saturated hydrocarbons such as hexane, heptane, octane, isooctane, decane, and dodecane; and esters such as ethyl acetate, isopropyl acetate, ceroxythrene acetate, and ethyl propionate. Furthermore, even when the aromatic vinyl monomer is styrene... Good solvents for polystyrene, such as alkanes, THF, and toluene, can also be used as organic solvents when used in combination with the aforementioned unsuitable solvents in small quantities. The amount of these organic solvents used should ideally be 30-80% by weight of the aromatic vinyl monomer concentration. If the amount of organic solvent used falls outside this range and the aromatic vinyl monomer concentration is less than 30% by weight, the polymerization rate will decrease, or the resulting monolithic structure may fall outside the range of monolith a, which is less desirable. On the other hand, if the aromatic vinyl monomer concentration exceeds 80% by weight, there is a risk of uncontrolled polymerization, which is also less desirable.

[0060] The polymerization initiator used in step II of the method for manufacturing monomer a can be a compound that generates free radicals upon exposure to heat or light. The polymerization initiator should preferably be oil-soluble. Specific examples of polymerization initiators include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, 4,4'-azobis(4-cyanopentanoic acid), 1,1'-azobis(cyclohexane-1-carboxynitrile), benzoyl peroxide, lauryl peroxide, potassium persulfate, ammonium persulfate, sulfide, etc. The amount of polymerization initiator used varies greatly depending on the type of monomer and the polymerization temperature; relative to the total amount of vinyl monomer and crosslinking agent, it can be used in the range of approximately 0.01% to 5%.

[0061] Step III of the method for manufacturing monolith a involves polymerizing the mixture obtained in step II under static conditions in the presence of the monolith intermediate a obtained in step I, thereby changing the continuous macroporous structure of the monolith intermediate a into a co-continuous structure, and obtaining monolith a as a monolith with a co-continuous structure. The monolith intermediate a used in step III plays a crucial role in creating monoliths with the structure of this invention. As disclosed in Japanese Patent Application Publication No. 7-501140, if vinyl monomers and crosslinking agents are polymerized in a specific organic solvent without the presence of the monolith intermediate a, a particle-aggregated monolithic organic porous body is obtained. In contrast, if a monolith intermediate a with a specific continuous macroporous structure, as in monolith a, exists in the above-mentioned polymerization system, the structure of the polymerized monolith changes drastically, particle aggregation disappears, and a monolith a with the aforementioned co-continuous structure can be obtained. While the details of the reasoning are not yet clear, it is believed that in the absence of a monolithic intermediate a, the cross-linked polymer produced by polymerization will precipitate and form particles, thus creating a particle aggregate structure. Conversely, if a porous body (intermediate) with a large total pore volume exists in the polymerization system, the vinyl monomer and cross-linking agent will be adsorbed or distributed from the liquid phase to the framework of the porous body, and polymerization will take place in the porous body. The framework of the monolithic structure will change from two-dimensional walls to one-dimensional rod-shaped framework, thus forming a monolith a with a co-continuous structure.

[0062] In the manufacturing method of monolith 'a', there is no particular limitation on the internal volume of the reaction vessel, as long as it is large enough to contain the monolith intermediate 'a'. Either the monolith intermediate 'a' has gaps around it when viewed from above, or it is filled into the reaction vessel without gaps, are acceptable. Among these, a more efficient method results in a solid monolith that enters the reaction vessel without being squeezed by the inner wall, preventing strain and waste of reaction materials. Furthermore, even if the internal volume of the reaction vessel is large and gaps exist around the polymerized monolith, the vinyl monomer and crosslinking agent are adsorbed and distributed within the monolith intermediate 'a', thus preventing the formation of particle agglomerates in the gaps within the reaction vessel.

[0063] In step III of the method for manufacturing monolithic intermediate a, monolithic intermediate a is placed in a reaction vessel while impregnated in the mixture (solution). The blending ratio of the mixture obtained in step II to monolithic intermediate a, as described above, is preferably 3 to 50 times the weight of the vinyl monomer relative to monolithic intermediate a, and more preferably 4 to 40 times. This yields monolithic a with an appropriate aperture and a robust skeleton. In the reaction vessel, the vinyl monomer and crosslinking agent in the mixture are adsorbed and distributed within the skeleton of the stationary monolithic intermediate a, and polymerization occurs within the skeleton of monolithic intermediate a.

[0064] In step III of the method for manufacturing monolithic intermediate a, monolithic intermediate a is placed in a reaction vessel in a state of being impregnated in the mixture (solution). The blending ratio of the mixture obtained in step II to monolithic intermediate a, as described above, is preferably 5 to 50 times by weight of the aromatic vinyl monomer relative to monolithic intermediate a, and more preferably 5 to 40 times. This yields monolithic a with a co-continuous structure of appropriately sized pores in three dimensions and a coarse, continuous framework in three dimensions. In the reaction vessel, the aromatic vinyl monomer and crosslinking agent in the mixture are adsorbed and distributed onto the framework of the stationary monolithic intermediate a, and polymerization occurs within the framework of the monolithic intermediate a.

[0065] The polymerization conditions in step III of the method for manufacturing monolith a depend on the type of monomer and the type of initiator. For example, when using 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylpentanonitrile), benzoyl peroxide, lauryl peroxide, potassium persulfate, etc., as initiators, polymerization can be carried out at 30-100°C for 1-48 hours in a sealed container under inert conditions. Through heating polymerization, the vinyl monomers and crosslinking agents adsorbed and distributed in the backbone of monolith intermediate a polymerize within the backbone, making the backbone coarser. After polymerization, the contents are removed, and monolith a is obtained by extraction with solvents such as acetone to remove unreacted vinyl monomers and organic solvents.

[0066] Monolithic anion exchanger a can be obtained by performing step IV, which introduces anion exchange groups into the monolithic a obtained in step III. There are no particular limitations on the method of introducing anion exchange groups into the aforementioned monomer a, and known methods such as polymer reactions or graft polymerization can be used. For example, methods for introducing quaternary ammonium groups include: if the monolith is a styrene-divinylbenzene copolymer, a method is to introduce chloromethyl groups using chloromethyl methyl ethers, etc., and then react it with a tertiary amine; a method is to manufacture a monolith by copolymerizing chloromethyl styrene with divinylbenzene and then reacting it with a tertiary amine; for the monolith, a method is to uniformly introduce free radical initiators and chain transfer groups into the surface and interior of the backbone, and then perform graft polymerization of N,N,N-trimethylammonium ethyl acrylate or N,N,N-trimethylammonium propyl acrylate; similarly, a method is to introduce quaternary ammonium groups by graft polymerization of glycidyl methacrylate and then by functional group conversion, etc. Among these methods, regarding the introduction of quaternary ammonium groups, the method of introducing chloromethyl groups into styrene-divinylbenzene copolymers via chloromethyl methyl ethers and then reacting them with tertiary amines, or the method of manufacturing monoliths by copolymerizing chloromethylstyrene with divinylbenzene and then reacting them with tertiary amines, is more ideal in terms of uniformly and quantitatively introducing ion exchange groups. Furthermore, examples of quaternary ammonium groups such as trimethylammonium, triethylammonium, tributylammonium, dimethylhydroxyethylammonium, dimethylhydroxypropylammonium, and methyldihydroxyethylammonium, or tert-silyl and phosphonium groups, can be listed as ion exchange groups to be introduced.

[0067] Although the size of the continuous pores in the three dimensions of the monolithic a and monolithic anion exchanger a is particularly large, it has high mechanical strength due to its robust framework. In addition, the robust framework of the monolithic anion exchanger a allows for a large cation exchange capacity per unit volume in a water-wetted state, further enabling the treated liquid to be passed through at low pressure and high flow rate for a long time.

[0068] <Anion exchange resin> In this invention, when the anion exchanger is an anion exchange resin, there are no particular limitations on the type of anion exchange resin. It is preferable to use an organic polymer system with an organic polymer as the parent material. Examples of organic polymers that serve as the parent material include styrene-based resins and acrylic resins.

[0069] In this specification, styrene-based resin refers to a resin formed by homopolymerization or copolymerization of styrene or styrene derivatives, containing 50% by mass or more of the constituent units derived from styrene or styrene derivatives.

[0070] Examples of styrene derivatives include α-methylstyrene, vinyltoluene, chlorostyrene, ethylstyrene, isopropylstyrene, dimethylstyrene, and bromostyrene.

[0071] As for styrene-based resins, any homopolymer or copolymer of styrene or styrene derivatives as the main component is acceptable, or it can be a copolymer of other copolymerizable vinyl monomers. Examples of such vinyl monomers include, for instance, divinylbenzene such as o-divinylbenzene, m-divinylbenzene, p-divinylbenzene, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, alkyl glycol di(meth)acrylate, or other multifunctional monomers, or (meth)acrylonitrile, (meth)acrylate, methyl methacrylate, etc.

[0072] Of the other vinyl monomers that can be copolymerized as described above, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate with an ethyl copolymer number of 4 to 16, and divinylbenzene are more preferred, and divinylbenzene and ethylene glycol di(meth)acrylate are even more preferred.

[0073] In this specification, acrylic resin refers to a resin obtained by homopolymerization or copolymerization of one or more selected from acrylic acid, methacrylic acid, acrylate and methacrylate, containing 50% or more of the constituent units selected from acrylic acid, methacrylic acid, acrylate and methacrylate.

[0074] More specifically, the acrylic resins mentioned above may be selected from one or more of the following: homopolymers of acrylic acid, homopolymers of methacrylic acid, homopolymers of acrylates, homopolymers of methacrylates, copolymers of acrylic acid with other monomers (e.g., acrylates, methacrylic acid, methacrylates, α-olefins (e.g., ethylene, divinylbenzene, etc.)), copolymers of methacrylic acid with other monomers (e.g., acrylic acid, acrylates, methacrylates, α-olefins (e.g., ethylene, divinylbenzene, etc.)), copolymers of acrylates with other monomers (e.g., acrylic acid, methacrylic acid, methacrylates, α-olefins (e.g., ethylene, divinylbenzene, etc.)), and copolymers of methacrylates with other monomers (e.g., acrylic acid, acrylates, methacrylic acid, α-olefins (e.g., ethylene, divinylbenzene, etc.)). Among these, divinylbenzene methacrylate copolymers or divinylbenzene acrylate copolymers are preferred.

[0075] As an acrylate, it is preferable to be an alkyl acrylate, more preferably a straight-chain alkyl acrylate or a branched-chain alkyl acrylate, and even more preferably a straight-chain alkyl acrylate. As an acrylate, it is more preferable to be an alkyl acrylate in which the alkyl group of the alkyl group has 1 to 4 carbon atoms, and even more preferably to be methyl acrylate or ethyl acrylate, especially methyl acrylate.

[0076] As a methacrylate, it is preferable to be an alkyl methacrylate, more preferably a straight-chain alkyl methacrylate or a branched-chain alkyl methacrylate, and even more preferably a straight-chain alkyl methacrylate. As a methacrylate, it is more preferable to be an alkyl methacrylate in which the alkyl group contains 1 to 4 carbon atoms, and even more preferably to be methyl methacrylate or ethyl methacrylate, especially methyl methacrylate.

[0077] Regarding the aforementioned anion exchange resins, examples include those with strong basicity and quaternary ammonium groups as anion exchange groups, and those with weak basicity and amine groups as anion exchange groups. In the ion exchange resin pretreatment apparatus of the present invention, the ion exchange resin containing the non-aqueous solvent in the ion exchange resin container is preferably a weakly basic ion exchange resin.

[0078] Regarding the weakly basic ion exchange groups that constitute weakly basic ion exchange resins, primary to tertiary amine groups are preferred.

[0079] Such anion exchange resins can be commercially available, and for example, can be selected from one or more of the following: DIAION WA30 manufactured by Mitsubishi Chemical Co., Ltd., ORLITEDS-6 manufactured by Orlucan Co., Ltd.

[0080] The aforementioned anion exchange resins may have a gel-type structure, a macroreticular (MR) type structure, a macroporous (MP) type structure, or a porous (porous) type structure.

[0081] There are no particular limitations on the size of the above-mentioned anion exchange resin, but its average diameter should preferably be 300~1000μm, more preferably 400~800μm, and even more preferably 500~700μm.

[0082] Furthermore, for the aforementioned anion exchange resin, its total ion exchange capacity in the wet state is preferably 0.1 to 3.0 (eq / LR), more preferably 0.5 to 2.5 (eq / LR), and even more preferably 1.0 to 2.0 (eq / LR).

[0083] In this invention, there are no particular restrictions on the form in which the anion exchanger can be contained, as long as it can come into contact with the aqueous solution of the quaternary ammonium hydroxide described later. For example, the container of anion exchangers can also be a column or tank filled with an aqueous solution of quaternary ammonium hydroxide. The aforementioned tubing or tank may also be equipped with a pump for circulating an aqueous solution of grade IV ammonium hydroxide.

[0084] <Ion Morphological Changes of Anion Exchangers> In this invention, the above-mentioned anion exchanger is contacted with an aqueous solution of quaternary ammonium hydroxide. In this invention, the following states (a) to (c) can be listed as states for contacting an anion exchanger with an aqueous solution of quaternary ammonium hydroxide. (State(a)) By contacting the anion exchanger with an aqueous solution of quaternary ammonium hydroxide, the ionic form of the anion exchanger is changed. (Style(b)) The anion exchanger is brought into contact with an inorganic acid, then washed with water, and then brought into contact with an aqueous solution of quaternary ammonium hydroxide to change the ionic state of the anion exchanger. (State(c)) The anion exchanger is contacted with an inorganic acid, then washed with water, then contacted with hydrochloric acid, then washed with water, and finally contacted with an aqueous solution of the aforementioned quaternary ammonium hydroxide. By using any of the states (a) to (c) mentioned above, the ionic form of the anion exchanger can be effectively changed to the OH form. In this invention, it is preferable to change the ionic form of the anion exchanger by state (b) or state (c), and it is even more preferable to change the ionic form of the anion exchanger by state (c). Unless otherwise specified, the following descriptions are common to states (a) through (c).

[0085] As illustrated in the above examples (a) to (c), in this invention, the anion exchanger is contacted with an aqueous solution of quaternary ammonium hydroxide. Quaternary ammonium hydroxide For quaternary ammonium hydroxides, it is preferable to select one or more compounds represented by the following general formula (I). [Chemistry 2] (In the formula, R1 to R4 may each have a hydrocarbon group with 1 to 4 carbon atoms of a hydroxyl group, and they may be the same or different.)

[0086] In addition to hydrogen atoms, R1 to R4 can also include straight-chain or branched-chain hydrocarbon groups that may have hydroxyl groups, such as methyl, ethyl, n-propyl, isopropyl, and butyl. R1 to R4 can be the same or different from each other.

[0087] Specifically, compounds represented by the following general formula (I) may be selected from one or more of the following: trimethylhydroxyammonium, tetramethylammonium hydroxide (TMAH), trimethylhydroxyethylammonium hydroxide (choline), methyltrihydroxyethylammonium hydroxide, dimethyldihydroxyethylammonium hydroxide, tetraethylammonium hydroxide, trimethylethylammonium hydroxide, tetrabutylammonium hydroxide (TBAH).

[0088] In this invention, the concentration of quaternary ammonium hydroxide in the aqueous solution of quaternary ammonium hydroxide is preferably 0.1~2.0N, more preferably 0.5~2.0N, and even more preferably 0.5~1.0N. Furthermore, in this invention, the concentration of metal impurities in the aqueous solution of the aforementioned grade IV ammonium hydroxide is preferably below 1000 ng / L, and more preferably below 100 ng / L. Furthermore, the concentration of metallic impurities in this specification refers to the value measured using inductively coupled plasma mass analysis (ICP-MS, Agilent Technologies, Ltd., Agilent 7500cs).

[0089] In this invention, the flow rate (liquid space velocity) of the aqueous solution of quaternary ammonium hydroxide through the anion exchanger is not particularly limited as long as it is high enough to change the relative ions of the anion exchanger groups constituting the anion exchanger into the OH form.

[0090] In this invention, for the above-mentioned anion exchanger, it is ideal to pass an aqueous solution of quaternary ammonium hydroxide through a liquid space velocity (SV, flow rate / anion exchanger volume ratio) of less than 20,000 h⁻¹, more preferably 10 to 4,000 h⁻¹, and even more preferably 300 to 1,000 h⁻¹.

[0091] In this invention, the volumetric flow rate of the aqueous solution of the quaternary ammonium hydroxide of the above-mentioned anion exchanger is preferably 5 to 100 times, more preferably 10 to 100 times, and even more preferably 15 to 75 times, based on volume.

[0092] In this invention, for the anion exchanger contained in the container, it is more ideal to pass the liquid through an aqueous solution of quaternary ammonium hydroxide in an upward or downward flow to ensure contact between the two. More preferably, for the anion exchanger contained in the container, it is more ideal to pass the liquid through an aqueous solution of quaternary ammonium hydroxide in an upward flow to ensure contact between the two.

[0093] For example, as shown in Figure 4, the following liquid flow treatment is performed: the aqueous solution S of quaternary ammonium hydroxide stored in tank 4 is pumped upward from the bottom to the top of the container 3 containing the above-mentioned anion exchanger using pump P, and the outflowing liquid W is stored in storage tank 5.

[0094] By passing an aqueous solution of quaternary ammonium hydroxide into the anion exchanger contained in container 3 in an upward flow, even if air bubbles are mixed in the anion exchanger contained in container 3, the air bubbles in the anion exchanger can be de-bubbled and removed as the aqueous solution of quaternary ammonium hydroxide flows upward through the anion exchanger. Therefore, even if there are air bubbles mixed in the anion exchanger, the ionic form of the anion exchanger can be easily and quickly changed to the OH form at a high ratio while maintaining proper contact between the aqueous solution of quaternary ammonium hydroxide and the anion exchanger.

[0095] In this invention, as illustrated in states (b) and (c) above, the anion exchanger is preferably contacted with an inorganic acid before being contacted with an aqueous solution of quaternary ammonium hydroxide. As an inorganic acid, it can be selected from one or more of nitric acid, hydrochloric acid, sulfuric acid, etc., preferably from one or more of nitric acid and hydrochloric acid, and more preferably nitric acid.

[0096] In this invention, the concentration of the inorganic acid is preferably 0.1~2.0N, more preferably 0.5~2.0N, and even more preferably 1.0~2.0N. Furthermore, in this invention, the concentration of metallic impurities in the aforementioned inorganic acid is preferably below 100 ng / L, and more preferably below 10 ng / L.

[0097] In this invention, for the above-mentioned anion exchanger, it is ideal to pass inorganic acid through the liquid space velocity (SV, flow rate / anion exchanger volume ratio) at a rate of 20,000 h⁻¹ or less, more preferably 10 to 4,000 h⁻¹, and even more preferably 300 to 1,000 h⁻¹.

[0098] In this invention, the volumetric flow rate of the inorganic acid to the above-mentioned anion exchanger is preferably 5 to 100 times, more preferably 10 to 100 times, and even more preferably 15 to 75 times.

[0099] In this invention, it is ideal to pass the inorganic acid through the anion exchanger contained in the container in an upward or downward flow to bring the two into contact. More preferably, the inorganic acid is passed through the anion exchanger contained in the container in an upward flow to bring the two into contact. Specifically, this situation can be illustrated by a contact state in which inorganic acid stored in the tank is pumped upward from the bottom to the top of the container containing the anion exchanger using a pump P, similar to the state shown in Figure 4 above.

[0100] Then, the anion exchanger that has been in contact with the inorganic acid is washed with water. The above-mentioned water-based cleaning treatment does not have any particular limitations on the flow rate or time, as long as it allows the remaining nitric acid in the anion exchanger to flow out.

[0101] In the above-mentioned sample (b), the anion exchanger, after being contacted with an inorganic acid by the above method and then washed with water, is contacted with an aqueous solution of quaternary ammonium hydroxide. The details of the method for contacting the anion exchanger with an aqueous solution of quaternary ammonium hydroxide are the same as those described above.

[0102] In embodiment (b) of the present invention, by contacting the anion exchanger with an inorganic acid, at least a portion of the anions constituting the anion exchanger can be replaced with the corresponding ionic form. Then, by contacting it with an aqueous solution of quaternary ammonium hydroxide, it can be easily and quickly converted into the OH form (hydroxide ions) at a high ratio. For example, in embodiment (b) of the present invention, by contacting the anion exchanger with nitric acid or hydrochloric acid, at least a portion of the anions constituting the anion exchanger can be replaced with nitrate ions or chloride ions. Then, by contacting it with an aqueous solution of quaternary ammonium hydroxide, it is possible to easily and quickly change from the nitrate form (nitrate ions) or hydrochloric acid form (chloride ions) to the OH form (hydroxide ions) at a high ratio.

[0103] In this invention, as illustrated in state (c) above, it is more ideal to contact the anion exchanger with an inorganic acid, then wash it with water, then contact it with hydrochloric acid, then wash it with water, and finally contact it with an aqueous solution of the above-mentioned quaternary ammonium hydroxide.

[0104] The details of the method of contacting the anion exchanger with an inorganic acid and then washing it with water are the same as those described above.

[0105] The anion exchanger obtained by contacting the above with an inorganic acid and then washing with water is further contacted with hydrochloric acid and then washed with water.

[0106] In this invention, the concentration of the hydrochloric acid (after contact with inorganic acid and washing with water) is preferably 0.1~2.0N, more preferably 0.5~2.0N, and even more preferably 1.0~2.0N. Furthermore, in this invention, the content of metallic impurities in the hydrochloric acid is preferably below 100 ng / L, more preferably below 10 ng / L.

[0107] In this invention, for the above-mentioned anion exchanger, it is ideal to pass hydrochloric acid through the liquid space velocity (SV, the ratio of hydrochloric acid flow rate to anion exchanger volume) at a rate of 20,000 h⁻¹ or less, more preferably 10 to 4,000 h⁻¹, and even more preferably 300 to 1,000 h⁻¹.

[0108] In this invention, the volumetric flow rate of hydrochloric acid through the anion exchanger is preferably 5 to 100 times, more preferably 10 to 100 times, and even more preferably 15 to 75 times.

[0109] In this invention, it is more ideal to pass hydrochloric acid through the anion exchanger contained in the container in an upward or downward flow to bring the two into contact. More preferably, hydrochloric acid is passed through the anion exchanger contained in the container in an upward flow to bring the two into contact. Specifically, this situation can be illustrated by a similar scenario to the one shown in Figure 4 above, in which hydrochloric acid stored in the tank is pumped from the bottom to the top of the container holding the anion exchanger in an upward flow manner.

[0110] Then, the anion exchanger that has been in contact with the hydrochloric acid is washed with water. The washing process with water is sufficient to allow any remaining hydrochloric acid in the anion exchanger to flow out; there are no particular restrictions on the flow rate or the flow time.

[0111] In the above-mentioned sample (c), the anion exchanger obtained by contacting an inorganic acid with the above method, then washing with water, then contacting hydrochloric acid, and then washing with water, is then contacted with an aqueous solution of quaternary ammonium hydroxide. The details of the method for contacting the anion exchanger with an aqueous solution of quaternary ammonium hydroxide are the same as those described above.

[0112] In embodiment (c) of the present invention, by initially cleaning the anion exchanger with an inorganic acid and then contacting it with hydrochloric acid to reduce the metal content of the anion exchanger, at least a portion of the anions constituting the anion exchanger can be replaced with chloride ions. After that, it is contacted with an aqueous solution of quaternary ammonium hydroxide, thereby easily and quickly changing from the hydrochloric acid form (chloride ions) to the OH form (hydroxide ions) at a high ratio.

[0113] The method for changing the ionic form of anion exchanger of the present invention, in order to change the ionic form of anion exchanger used in the purification of ultrapure water or pharmaceutical solution, or in order to change the ionic form of anion exchanger used in the analysis of anionic impurities in ultrapure water or pharmaceutical solution, preferably involves contacting the aforementioned anion exchanger with an aqueous solution of quaternary ammonium hydroxide.

[0114] In implementing the method for changing the ionic form of anion exchanger according to the present invention to change the ionic form of the anion exchanger used in the purification of pharmaceutical solutions, there are no particular limitations on the pharmaceutical solutions mentioned above, and one or more of the following can be selected: hydrogen peroxide, hydrochloric acid, hydrofluoric acid, phosphoric acid, acetic acid, tetramethylammonium hydroxide, ammonium fluoride, acetone, 2-butanone, n-butyl acetate, ethanol, methanol, 2-propanol, toluene, xylene, propylene glycol methyl ether acetate, N-methyl-2-pyrrolidone, ethyl lactate, phenolic compounds, dimethyl sulfoxide, tetrahydrofuran, γ-butyl lactone, and polyethylene glycol monomethyl ether (PGMEA).

[0115] In implementing the anion exchanger ion form modification method of the present invention to change the ion form of the anion exchanger used in the analysis of anionic impurities in a pharmaceutical solution, there are no particular limitations on the pharmaceutical solution mentioned above, and examples can be selected from one or more of the following: tetramethylammonium hydroxide, ammonium fluoride, acetone, 2-butanone, n-butyl acetate, ethanol, methanol, 2-propanol, toluene, xylene, propylene glycol methyl ether acetate, N-methyl-2-pyrrolidone, ethyl lactate, phenolic compounds, dimethyl sulfoxide, tetrahydrofuran, γ-butyl lactone, and polyethylene glycol monomethyl ether (PGMEA).

[0116] In the case of changing the ionic form of anion exchanger used in the purification of ultrapure water by implementing the method of changing the ionic form of anion exchanger of the present invention, the anion exchanger may be an assembly in the same manufacturing step for purifying ultrapure water used in various manufacturing steps, or it may be a user for recycling and purifying used ultrapure water.

[0117] In the case of changing the ion form of anion exchanger used in the refining of a pharmaceutical solution by implementing the method of changing the ion form of anion exchanger of the present invention, the anion exchanger may be used to assemble in the manufacturing step of the pharmaceutical solution for refining, or it may be used to further refine the manufactured pharmaceutical solution.

[0118] Next, the usage of the anion exchanger regenerated by means of the present invention will be described. Figure 5(a) shows a purification apparatus U, assembled downstream of any point of use where ultrapure water is supplied, in various manufacturing processes. A container A containing anion exchangers and a container C containing cation exchangers are connected in a water-flow-enabled state. In the configuration shown in Figure 5(a), ultrapure water flows in from one end of container A, circulates through containers A and C, and then flows out from the other end of container C. By loading the anion exchanger regenerated according to the present invention into the container A, even if there are metal components remaining in the anion exchanger during regeneration and these metal components flow out, they can be easily removed by the cation exchanger disposed downstream of the anion exchanger. On the other hand, Figure 5(b) illustrates a purification apparatus U, assembled downstream of any point of use where ultrapure water is supplied, in various manufacturing processes. The apparatus consists of a container C containing a cation exchanger and a container A containing an anion exchanger, connected in a water-flow-through state. In the configuration shown in Figure 5(b), ultrapure water flows in from one end of container C, circulates through both containers C and A, and then flows out from the other end of container A. The anion exchanger regenerated by this invention significantly reduces the residual metal content during regeneration. Therefore, even when a container A containing the anion exchanger regenerated by this invention is placed downstream of a container C containing a cation exchanger, the outflow of various metals from the anion exchanger can be effectively suppressed. Furthermore, even if negatively charged particles or other impurities flow out of the cation exchanger in container C, they can be easily removed by the anion exchanger in container A located downstream.

[0119] According to the present invention, a method is provided for easily and quickly changing the ionic form of anion exchanger to the OH form at a high rate while suppressing the residue of various metals.

[0120] Next, the method for manufacturing the anion exchanger of the present invention will be described. The method for manufacturing anion exchangers of the present invention is characterized in that, in order to change the ionic form of the anion exchanger, the anion exchanger is brought into contact with an aqueous solution of quaternary ammonium hydroxide.

[0121] The details of the method for changing the ionic form of the anion exchanger to be manufactured in the manufacturing method of the present invention are as described in the description of the method for changing the ionic form of the anion exchanger of the present invention.

[0122] Regarding the manufacturing method of the anion exchanger of the present invention, in order to change the ionic form of the anion exchanger used in the purification of ultrapure water or the purification of pharmaceutical solutions, or in order to change the ionic form of the anion exchanger used in the analysis of anionic impurities in ultrapure water or pharmaceutical solutions, it is possible to contact the above-mentioned anion exchanger with an aqueous solution of quaternary ammonium hydroxide, thereby changing the ionic form of the anion exchanger while suppressing the residue of various metals.

[0123] More specifically, as a method for manufacturing anion exchangers according to the present invention, examples can be given of methods for changing the ionic form of anion exchangers used in the manufacturing of anion exchangers used in the purification of ultrapure water or pharmaceutical solutions, that is, in the preparation or regeneration of anion exchangers used in the removal of anionic impurities in ultrapure water or pharmaceutical solutions, in order to change their ionic form.

[0124] Furthermore, as a method for manufacturing the anion exchanger of the present invention, examples can be given of manufacturing anion exchangers used in the analysis of anionic impurities in ultrapure water or pharmaceutical solutions, that is, during the preparation or regeneration of anion exchangers used in the analysis of anionic impurities in ultrapure water or pharmaceutical solutions, in order to change their ionic form using the ion form changing method of the anion exchanger of the present invention.

[0125] According to the present invention, a method for manufacturing an anion exchanger is provided that can easily and quickly change the ionic form of the anion exchanger to the OH form at a high rate while suppressing the residue of various metals. Example

[0126] The invention will then be illustrated more specifically by way of examples, which are merely illustrative and do not limit the invention.

[0127] A monolithic anion exchanger and a monolithic cation exchanger were manufactured using the same method as in Example 17 of the embodiment described in Japanese Patent Application Publication No. 2010-234357. (Refer to Example 1) <Manufacturing of Monolithic Anion Exchangers and Monolithic Cation Exchangers> (Step I; Manufacturing of a single intermediate block) 5.4 g of styrene, 0.17 g of divinylbenzene, 1.4 g of sorbitan monooleate (SMO), and 0.26 g of 2,2'-azobis(isobutyronitrile) were mixed and dissolved uniformly. Then, this styrene / divinylbenzene / SMO / 2,2'-azobis(isobutyronitrile) mixture was added to 180 g of pure water, and stirred under reduced pressure using a vacuum-stirred defoaming mixer (manufactured by EME Corporation) with a planetary stirrer within a temperature range of 5–20 °C to obtain an oil-water droplet emulsion. This emulsion was rapidly transferred to a reaction vessel, sealed, and allowed to polymerize at 60 °C for 24 hours under static conditions. After polymerization, the contents were removed, extracted with methanol, and dried under reduced pressure to produce a monolithic intermediate with a continuous macroporous structure. The internal structure of the single intermediate (dried body) obtained in this way was observed by SEM images. The walls of two adjacent macropores were extremely fine rod-shaped, but had a continuous bubble structure. The average diameter of the opening (mesopore) of the overlapping part of the macropores, measured by mercury infiltration method, was 70 μm, and the total micropore volume was 21.0 ml / g.

[0128] (Manufacturing of a continuous structural monolith) Then, 76.0 g of styrene, 4.0 g of divinylbenzene, 120 g of 1-decyl alcohol, and 0.8 g of 2,2'-azobis(2,4-dimethylpentanonitrile) were mixed and dissolved uniformly (Step II). Then, 4.1 g of the above monolithic intermediate was cut into discs with a diameter of 70 mm and a thickness of approximately 40 mm. The collected monolithic intermediate was added to a reaction vessel with an inner diameter of 110 mm and immersed in the styrene / divinylbenzene / 1-decyl alcohol / 2,2'-azobis(2,4-dimethylpentanonitrile) mixture. After defoaming in a vacuum chamber, the reaction vessel was sealed and polymerized at 60 °C for 24 hours under static conditions. After polymerization, the contents of a monolithic sample with a thickness of approximately 60 mm were removed, extracted with acetone using a Soxhlet extract, and then dried under reduced pressure overnight at 85 °C (Step III).

[0129] The internal structure of the monolith (dried body) containing 3.2 moles of crosslinking component, composed of styrene / divinylbenzene copolymer, obtained in this manner, was observed using SEM. The results showed that the monolith exhibited a co-continuous structure where the framework and pores were each continuous in three dimensions and interwoven. Furthermore, the framework thickness, as determined by SEM images, was 17 μm. Additionally, the size of the three-dimensionally continuous pores in the monolith, determined by mercury infiltration, was 41 μm, and the total pore volume was 2.9 ml / g.

[0130] (Manufacturing of a continuous structure monolithic anion exchanger) The monolith obtained by the above method was cut into discs with a diameter of 70 mm and a thickness of approximately 50 mm. 4700 ml of dimethoxymethane and 67 ml of tin tetrachloride were added, followed by the dropwise addition of 1870 ml of chlorosulfonic acid under ice-cold conditions. After the addition was complete, the mixture was heated to 35°C and reacted for 5 hours, introducing chloromethyl groups. After the reaction, the mother liquor was siphoned off, washed with a 2 / 1 mixture of THF and water, and then washed again with THF. 3400 ml of THF and 2000 ml of a 30% aqueous solution of trimethylamine were added to the chloromethylated monolithic organic porous plasmid, and the mixture was reacted at 60°C for 6 hours. After the reaction, the product was washed with a methanol / water mixture, then washed with pure water and separated to obtain a monolithic anion exchanger a with a co-continuous structure.

[0131] (Manufacturing of a continuous monolithic cation exchanger) The monolithic cation exchanger obtained by the above method was cut into discs with a diameter of 75 mm and a thickness of approximately 15 mm. 1500 ml of dichloromethane was added, and the mixture was heated at 35°C for 1 hour. After cooling to below 10°C, 99 g of chlorosulfonic acid was slowly added, and the mixture was heated to 35°C for 24 hours. Then, methanol was added to quench the reaction with residual chlorosulfonic acid. The mixture was then washed with methanol to remove dichloromethane, and further washed with pure water to obtain a monolithic cation exchanger c with a co-continuous structure.

[0132] (Analysis of a single anion exchanger a) A portion of the obtained monolithic anion exchanger a was cut off, dried, and its internal structure was observed using SEM, confirming the maintenance of a co-continuous structure. Furthermore, the swelling rate of the monolithic anion exchanger a before and after the reaction was 1.4 times, and the anion exchange capacity per unit volume in the water-wetted state was 0.72 mg equivalents / ml. The size of the continuous pores in the water-wetted monolith, estimated from the monolithic values ​​and the swelling rate of the water-wetted cation exchanger, was 70 μm, the framework diameter was 23 μm, and the total micropore volume was 2.9 ml / g.

[0133] Furthermore, the differential pressure coefficient, an indicator of pressure loss during water permeation, is 0.005 MPa / m·LV. Additionally, the ion exchange band length of chloride ions in this single anion exchanger a was measured, and it was 16 mm at LV = 20 m / h.

[0134] Then, to confirm the distribution of quaternary ammonium groups in the monolithic anion exchanger a, anion exchanger a was treated with hydrochloric acid aqueous solution to become the chloride form, and the distribution of chlorine atoms was observed by EPMA. As a result, it was observed that the quaternary ammonium groups were individually and uniformly introduced into the surface and interior (cross-sectional direction) of the anion exchanger framework.

[0135] (Analysis of a single cation exchanger) Furthermore, a portion of the obtained monolithic cation exchanger c was cut off and dried. Its internal structure was observed using SEM, confirming that the monolithic cation exchanger c maintained a co-continuous structure. Additionally, the swelling rate of the monolithic cation exchanger c before and after the reaction was 1.4 times, and the cation exchange capacity per unit volume in the water-wetted state was 0.72 mg equivalents / ml. The size of the continuous pores in the water-wetted state, estimated from the values ​​of the monolithic piece and the swelling rate of the cation exchanger in the water-wetted state, was 70 μm, the framework diameter (average coarseness) was 23 μm, and the total micropore volume was 2.9 ml / g.

[0136] Furthermore, the differential pressure coefficient, an indicator of pressure loss during water permeation, is 0.005 MPa / m·LV. Additionally, the ion exchange band length of sodium ions in this monolithic cation exchanger c was measured, and at LV=20 m / h, the ion exchange band length was 16 mm. This is not only overwhelmingly shorter than the value (320 mm) of Amberlite I R120B (manufactured by Dow Chemical Company), a commercially available strongly acidic cation exchange resin, but also shorter than the value of previous monolithic porous cation exchangers with continuous bubble structures.

[0137] Then, to confirm the distribution of sulfonic acid groups in monolithic cation exchanger c, the distribution of sulfur atoms was observed using EPMA. The results showed that the sulfonic acid groups were uniformly introduced into both the surface and interior (cross-sectional direction) of the cation exchanger framework.

[0138] <Methods for the Analysis of Metallic Elements> In the following examples and comparative examples, the amount of metal elements in the aqueous solvent (mass ppb) refers to the value determined using inductively coupled plasma mass analysis (ICP-MS, Agilent Technologies, Ltd., Agilent 7500cs).

[0139] (Example 1) A portion of the synthesized monolithic anion exchanger a was filled into a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) column with an inner diameter of 10 mm and a height of 50 mm, to prepare an anion exchanger packed column A. The ion form is changed by performing the following (1) to (3) processes on the anion exchanger-filled column A. (1) Inorganic acid treatment and water washing treatment For the above-mentioned anion exchanger packed column A, 300 mL of 1.0N nitric acid aqueous solution (TAMAPURE-AA-100 manufactured by Tama Chemical Industry Co., Ltd.) was passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), and then ultrapure water was washed for 10 minutes at SV (flow rate / volume ratio of single anion exchanger) = 750 (50 ml / min). (2) Hydrochloric acid treatment and water washing treatment For the anion exchanger packed column A that has undergone the above treatment (1), 300 mL of 1.0 N hydrochloric acid aqueous solution (TAMAPURE-AA-100 manufactured by Tama Chemical Industry Co., Ltd.) was passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), and then ultrapure water was washed for 10 minutes at SV (flow rate / volume ratio of single anion exchanger) = 750 (50 ml / min). (3) Treatment with aqueous solution of quaternary ammonium hydroxide For the anion exchanger packed column A that has undergone the treatment described in (2) above, 300 mL of a 1.0N concentration of trimethylolpropanediol (TMAH) aqueous solution (TAMAPURE-AA TMAH manufactured by Tama Chemical Industry Co., Ltd.) was passed through at SV (flow rate / volume ratio of a single anion exchanger) = 1500 (100 ml / min), and then ultrapure water was washed for 10 minutes at SV (flow rate / volume ratio of a single anion exchanger) = 750 (50 ml / min). The total time required for the above (1) to (3) processes is approximately 40 minutes. After the liquid treatment in (3) above, ultrapure water was circulated, and the amount of metal elements in the effluent taken from the outlet at the end of the anion exchanger packed column A was measured. The results are shown in Table 1.

[0140] (Comparative Example 1) An anion exchanger a, identical to the single anion exchanger a used for ion form modification in Example 1, was filled in 3.9 mL into a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) column with an inner diameter of 10 mm and a height of 50 mm to prepare an anion exchanger packed column. The anion exchanger packed column was then subjected to the following treatments (1) to (4). (1) Inorganic acid treatment and water washing treatment For the above-mentioned anion exchanger packed column, 300 mL of 1.0N nitric acid aqueous solution was passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), followed by a 10-minute water washing treatment with ultrapure water at SV (flow rate / volume ratio of single anion exchanger) = 750 (50 ml / min). (2) Hydrochloric acid treatment and water washing treatment For the anion exchanger packed column that has undergone the above treatment (1), 300 mL of 1.0 N hydrochloric acid aqueous solution is passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), and then ultrapure water is washed for 10 minutes at SV (flow rate / volume ratio of single anion exchanger) = 750 (50 ml / min). (3) Bicarbonate treatment and water washing treatment For the anion exchanger packed column that has undergone the above treatment (2), 300 mL of 2.0% ammonium bicarbonate aqueous solution (Kanto Chemical Co., Ltd., Rokute Grade) was passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), and then ultrapure water was washed for 10 minutes at SV (flow rate / volume ratio of single anion exchanger) = 750 (50 ml / min). (4) Sodium hydroxide treatment For the anion exchanger packed column that has undergone the above treatment (3), 300 mL of 1.0 N sodium hydroxide aqueous solution (Kanto Chemical Co., Ltd., premium grade) is passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), and then ultrapure water is washed for 10 minutes at SV (flow rate / volume ratio of single anion exchanger) = 750 (50 ml / min). The total time required for the above (1) to (4) processes is approximately 60 minutes. After the liquid treatment in (4) above, ultrapure water was circulated, and the amount of metal elements in the effluent taken from the outlet of the anion exchanger column was measured. The results are shown in Table 1.

[0141] [Table 1] (Unit: ng / L) B Na Al K Ca Cr Co Ni As Cd Sn Ba Example 1 <DL <DL <DL <DL <DL <DL <DL <DL <DL <DL <DL <DL [[ID=ID=14]] Comparative Example 1 5 526 1 1 1 1 1 1 1 1 1 1 · In the table, <DL means less than the detection limit.

[0142] (Example 2) In the same manner as in Example 1, after performing (1) inorganic acid treatment and water washing treatment, (2) hydrochloric acid treatment and water washing treatment, and (3) treatment with an aqueous solution of quaternary ammonium hydroxide, for the anion exchange resin-packed column after the liquid passing treatment of (3) above, 100 ml of 1.0 N nitric acid was passed through, and the amount of metal elements in the nitric acid solution collected at the column outlet was measured. The results are shown in Table 2.

[0143] (Comparative Example 2) In the same manner as in Comparative Example 1, after performing (1) inorganic acid treatment and water washing treatment, (2) hydrochloric acid treatment and water washing treatment, (3) bicarbonate treatment and water washing treatment, and (4) sodium hydroxide treatment, for the anion exchange resin-packed column after the liquid passing treatment of (4) above, 100 ml of 1.0 N nitric acid was passed through, and the amount of metal elements in the nitric acid solution collected at the column outlet was measured. The results are shown in Table 2.

[0144] [Table 2] (Unit: ng / L) B Na Mg Al Tl V Cr Fe Cu Zn Ga As Pd Cd Ba Pb Example 2 <DL <DL <DL <DL <DL <DL <DL <DL <DL <DL <DL <DL <DL <DL <DL <DL Comparative Example 2 333 276 135 743 88 4 2440 2046 295 120 6 3 180 0 26 18 ·In the table, means less than the detection limit.

[0145] From the above results, it can be seen that in Example 1 and Example 2, when preparing the monolithic anion exchanger by contacting it with an aqueous solution of quaternary ammonium hydroxide, the anion exchanger can be prepared simply and in a short time while suppressing the residue of various metals. On the other hand, it can be seen that in Comparative Example 1 and Comparative Example 2, since the monolithic anion exchanger is contacted with an aqueous solution of sodium hydroxide during its preparation, the preparation steps are numerous and require a long time. In addition, a certain amount of various metal elements such as Na element remains in the monolithic anion exchanger. In particular, it can be seen that in Comparative Example 2, various metal elements contained in the aqueous ammonium bicarbonate solution or the aqueous sodium hydroxide solution used during the preparation of the monolithic anion exchanger are adsorbed and remain in the monolithic anion exchanger, and a large amount of them will flow out from the monolithic anion exchanger when nitric acid flows through.

[0146] (Example 3) As shown in Figure 5(a), for the anion exchanger filled column A prepared in the same manner as in Example 1, the cation exchanger filled column C, which is made by filling 3.9 mL of the above-mentioned single cation exchanger c into a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) column with an inner diameter of 10 mm and a height of 50 mm, is connected in a liquid-passing manner to obtain the purification device U. As shown in Figure 5(a), a Na ion aqueous solution with a concentration of 1000 ng / L is passed through the inlet at the end of the anion exchanger filling column A of the above-mentioned purification device U at a flow rate of SV (flow rate / anion exchanger volume ratio) = 1500 (100 ml / min). The Na ion concentration in the effluent flowing out from the outlet at the end of the cation exchanger filling column C of the above-mentioned purification device U is measured at regular intervals. The results are shown in Figure 6. In Figure 6, the removal performance of the purification device U is evaluated based on the change over time of the ratio of the Na ion concentration at the outlet of the cation exchanger-filled column to the Na ion concentration at the inlet of the anion exchanger-filled column (Na ion concentration at the outlet of the cation exchanger-filled column / Na ion concentration at the inlet of the anion exchanger-filled column).

[0147] (Comparative Example 3) A purification apparatus was prepared by connecting a cation exchanger-filled column, which was prepared in the same manner as in Comparative Example 1, to a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) column with 3.9 mL of the above-mentioned single cation exchanger c filled to an inner diameter of 10 mm and a height of 50 mm, in a liquid-passing manner. A Na ion aqueous solution with a concentration of 1000 ng / L is passed through the inlet at the end of the anion exchanger filling column of the above-mentioned purification device at a flow rate of SV (flow rate / anion exchanger volume ratio) = 1500 (100 ml / min). The Na ion concentration in the effluent flowing out from the outlet at the end of the cation exchanger filling column of the above-mentioned purification device is measured at regular intervals. The results are shown in Figure 6.

[0148] From the above results, it can be seen that in Example 3, because the regeneration of the single anion exchanger is in contact with the aqueous solution of quaternary ammonium hydroxide, the residual metal ions can be suppressed. Therefore, even if the aqueous solution of Na ions is flowing, the single cation exchanger can effectively remove Na ions and suppress their outflow. On the other hand, it can be seen that in Comparative Example 3, because the regeneration of the single anion exchanger is in contact with the aqueous solution of sodium hydroxide, the Na element remains in the single anion exchanger. Therefore, when the Na ion aqueous solution flows, the Na ions flow out from the single anion exchanger, thus increasing the Na ion loading of the subsequent single cation exchanger and reducing the removal performance.

[0149] (Example 4) A portion of the synthesized monolithic anion exchanger a was filled into a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) column with an inner diameter of 10 mm and a height of 50 mm, thus preparing an anion exchanger packed column. The above-mentioned anion exchanger packed column is regenerated by performing the following (1) to (3) processes. (1) Inorganic acid treatment and water washing treatment For the above-mentioned anion exchanger packed column, 300 mL of 1.0N nitric acid aqueous solution was passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), followed by a 10-minute water washing treatment with ultrapure water at SV (flow rate / volume ratio of single anion exchanger) = 750 (50 ml / min). (2) Hydrochloric acid treatment and water washing treatment For the above-mentioned anion exchanger packed column, 300 mL of 1.0N nitric acid aqueous solution was passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), followed by a 10-minute water washing treatment with ultrapure water at SV (flow rate / volume ratio of single anion exchanger) = 750 (50 ml / min). (3) Treatment with aqueous solution of quaternary ammonium hydroxide For the anion exchanger packed column described above, 80 mL of a 1.0N trimethylolpropane (TMAH) aqueous solution was passed through at an SV (flow rate / volume ratio of a single anion exchanger) of 800 (53 mL / min). The total time required for the above treatments (1) to (3) was approximately 35 minutes. The regeneration rate of the anion exchanger packed column obtained by performing the above treatments (1) to (3) can be calculated using the following method.

[0150] <Methods for Calculating Regeneration Rate> Regeneration rate (%) = {R-OH (meq / g) / Total ion exchange capacity (meq / g)} × 100

[0151] In this specification, R-OH refers to the amount of OH ions present as relative ions in the quaternary ammonium group (R) of the anion exchanger. Furthermore, in this specification, R-OH refers to the value obtained by titrating the recovered liquid with sulfuric acid after passing a sodium nitrate solution through an anion exchanger that has been regenerated using a prescribed method. Furthermore, in this specification, the total ion exchange capacity is the value obtained by passing hydrochloric acid through the above-mentioned anion exchanger to form Cl, then passing sodium nitrate through it, and finally measuring the recovered liquid by silver nitrate titration (Mohr Method). The results are shown in Table 3.

[0152] (Example 5) In Example 4, "(3) Treatment with aqueous solution of quaternary ammonium hydroxide", the flow rate of the 1.0N trimethylammonium hydroxide (TMAH) aqueous solution was changed to SV (flow rate / volume ratio of single anion exchanger) = 400 (25 ml / min). Otherwise, the anion exchanger packed column was regenerated in the same manner as in Example 4. The total time required for the above regeneration process is approximately 40 minutes. The regeneration rate of the anion exchanger-filled column obtained by performing the above regeneration treatment was calculated using the same method as in Example 4. The results are shown in Table 3.

[0153] (Example 6) After using the synthesized monolithic anion exchanger a in an ultrapure water production apparatus for one month, the column filled with anion exchanger was regenerated by processing it in the same manner as in Example 5. The total time required for the above regeneration process is approximately 40 minutes. The regeneration rate of the anion exchanger-filled column obtained by performing the above regeneration treatment was calculated using the same method as in Example 4. The results are shown in Table 3.

[0154] (Example 7) An anion exchanger packed column was prepared by filling 3.9 mL of the following anion exchange resin into a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) column with an inner diameter of 10 mm and a height of 50 mm. <Anion Exchange Resins> Cl-type strong base anion exchange resin (Dow Chemical Company Amberjet 4002, details below). Base material (resin material): styrene-based Ion exchange group: Quaternary ammonium group Ion exchange equivalent: 1.2 mg equivalent of anion exchange group / ml of moistened resin or higher Moisture content at saturated equilibrium: 40% by mass Ionic form in saturated water-wetted state: Cl form The anion exchange resin described above is used to replace the single anion exchanger a. Otherwise, the anion exchanger filling column is regenerated using the same treatment as in Example 3. The total time required for the above regeneration process is 35 minutes. The regeneration rate of the anion exchanger-filled column obtained by performing the above regeneration treatment was calculated using the same method as in Example 4. The results are shown in Table 3.

[0155] (Example 8) In Example 7, the flow rate of the 1.0N trimethylhydroxyammonium (TMAH) aqueous solution was changed to SV (flow rate / volume ratio of a single anion exchanger) = 400. Otherwise, the anion exchanger-filled column was regenerated in the same manner as in Example 5. The total time required for the above regeneration process is 40 minutes. The regeneration rate of the anion exchanger-filled column obtained by performing the above regeneration treatment was calculated using the same method as in Example 4. The results are shown in Table 3.

[0156] (Comparative Example 4) An anion exchanger packed column was prepared by filling 3.9 mL of the same anion exchange resin as the anion exchange resin used for regeneration in Example 7 into a PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) column with an inner diameter of 10 mm and a height of 50 mm. The above-mentioned anion exchanger packed column is regenerated by performing the following (1) to (4) processes. (1) Inorganic acid treatment and water washing treatment For the above-mentioned anion exchanger packed column, 300 mL of 1.0N nitric acid aqueous solution was passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), followed by a 10-minute water washing treatment with ultrapure water at SV (flow rate / volume ratio of anion exchange resin) = 750 (50 ml / min). (2) Hydrochloric acid treatment and water washing treatment For the above-mentioned anion exchanger packed column, 300 mL of 1.0N nitric acid aqueous solution was passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), followed by a 10-minute water washing treatment with ultrapure water at SV (flow rate / volume ratio of anion exchange resin) = 750 (50 ml / min). (3) Bicarbonate treatment and water washing treatment For the above-mentioned anion exchanger packed column, 300 mL of 2.0% ammonium bicarbonate aqueous solution (Kanto Chemical, Rotte Grade) was passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), followed by a 10-minute water washing treatment with ultrapure water at SV (flow rate / volume ratio of anion exchange resin) = 750 (50 ml / min). (4) Sodium hydroxide treatment For the above-mentioned anion exchanger packed column, 300 mL of 1.0 N sodium hydroxide aqueous solution was passed through at SV (flow rate / volume ratio of a single anion exchanger) = 800 (53 mL / min). The total time required for the regeneration process described in (1) to (4) above is approximately 60 minutes. The regeneration rate of the anion exchanger-filled column obtained by performing the above regeneration treatment was calculated using the same method as in Example 4. The results are shown in Table 3.

[0157] [Table 3] Anion exchangers Regenerative reagents Fluid permeation rate (SV, hr⁻¹) for regenerative reagent Regeneration rate (R-OH / cap%) Example 4 Monolithic anion exchanger Trimethylhydroxyammonium aqueous solution 800 87 Example 5 Monolithic anion exchanger Trimethylhydroxyammonium aqueous solution 400 87 Example 6 Monolithic anion exchanger Trimethylhydroxyammonium aqueous solution 400 88 Example 7 Anion exchange resin Trimethylhydroxyammonium aqueous solution 800 61 Example 8 Anion exchange resin Trimethylhydroxyammonium aqueous solution 400 59 Comparative Example 4 Anion exchange resin NaOH aqueous solution 800 50

[0158] From the above results, it can be seen that in Examples 4 to 8, because the ionic form of the anion exchanger is changed and regenerated by contacting an aqueous solution of quaternary ammonium hydroxide, the ionic form of the anion exchanger can be easily and quickly changed to the OH form at a high rate while suppressing the residue of various metals. On the other hand, it can be seen that in Comparative Example 4, because the anion exchanger is in contact with an aqueous solution of sodium hydroxide during regeneration, the regeneration process is multi-step and takes a long time, resulting in a poor regeneration rate.

[0159] (Example 9) After using a single piece of anion exchanger A for a certain period of time in the determination of metal impurities in ultrapure water, a portion of it was filled into a 3.9 mL PFA (tetrafluoroethylene-perfluoroethylene alkyl vinyl ether copolymer) column with an inner diameter of 10 mm and a height of 50 mm to prepare an anion exchanger packed column. The above-mentioned anion exchanger-filled column is regenerated by performing the following (1) to (3) processes to change the ionic form. (1) Inorganic acid treatment and water washing treatment For the above-mentioned anion exchanger packed column, 300 mL of 1.0N nitric acid was passed through at SV (flow rate / volume ratio of a single anion exchanger) = 1500 (100 ml / min) for liquid treatment, and then ultrapure water was passed through at SV (flow rate / volume ratio of a single anion exchanger) = 750 (50 ml / min) for 10 minutes for water washing treatment. (2) Hydrochloric acid treatment and water washing treatment For the anion exchanger packed column that has undergone the above treatment (1), 300 mL of 1.0 N hydrochloric acid aqueous solution is passed through at SV (flow rate / volume ratio of single anion exchanger) = 1500 (100 ml / min), and then ultrapure water is washed for 10 minutes at SV (flow rate / volume ratio of single anion exchanger) = 750 (50 ml / min). (3) Treatment with aqueous solution of quaternary ammonium hydroxide For the above-mentioned anion exchanger packed column, 300 mL of a 1.0N trimethylolpropionic acid (TMAH) aqueous solution was passed through at an SV (flow rate / volume ratio of a single anion exchanger) of 1500 (100 mL / min). The total time required for the above (1) to (3) processes is approximately 40 minutes. The regeneration rate of the anion exchanger-filled column obtained by performing the above (1) to (3) treatments was calculated using the same method as in Example 4 above. The results are shown in Table 4.

[0160] (Example 10) For the same anion exchange column as that obtained in Example 9, regeneration is performed by performing the following (1) to (3) process to change the ionic form. (1) Inorganic acid treatment and water washing treatment For the above-mentioned anion exchanger packed column, 300 mL of 1.0N nitric acid was passed through at SV (flow rate / volume ratio of a single anion exchanger) = 1500 (100 ml / min) for liquid treatment, and then ultrapure water was passed through at SV (flow rate / volume ratio of a single anion exchanger) = 750 (50 ml / min) for 10 minutes for water washing treatment. (2) Treatment with aqueous solution of quaternary ammonium hydroxide For the anion exchanger packed column that has undergone the treatment described in (1) above, 300 mL of a 1.0 N concentration trimethylolpropionic acid (TMAH) aqueous solution is passed through at SV (flow rate / volume ratio of a single anion exchanger) = 1500 (100 mL / min). The total time required for processing (1) and (2) above is approximately 25 minutes. The regeneration rate of the anion exchanger packed column obtained by performing the treatments (1) and (2) described above was calculated using the same method as in Example 4. The results are shown in Table 4.

[0161] (Example 11) After a certain period of time, the following anion exchange resin was used to determine the metal impurities in ultrapure water. A portion of the resin was then packed into a 3.9 mL PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) column with an inner diameter of 10 mm and a height of 50 mm to prepare an anion exchange packed column. <Anion Exchange Resins> Cl-type strong base anion exchange resin (Dow Chemical Company Amberjet 4002, details below). Base material (resin material): styrene-based Ion exchange group: Quaternary ammonium group Ion exchange equivalent: 1.2 mg equivalent of anion exchange group / ml of moistened resin or higher Moisture content at saturated equilibrium: 40% by mass Ionic form in saturated water-wetted state: Cl form The anion exchange resin described above is used to replace the single anion exchanger A. Otherwise, the anion exchanger-filled column is regenerated by processing in the same manner as in Example 2. The total time required for the above regeneration process is approximately 40 minutes. The regeneration rate of the anion exchanger-filled column obtained after performing the above regeneration treatment was calculated using the same method as in Example 4. The results are shown in Table 4.

[0162] (Example 12) An anion exchanger-filled column was fabricated using the same anion exchange resin as in Example 11, instead of the single anion exchanger A, and was regenerated by processing in the same manner as in Example 10. The total time required for the above regeneration process is approximately 25 minutes. The regeneration rate of the anion exchanger-filled column obtained after performing the above regeneration treatment was calculated using the same method as in Example 4. The results are shown in Table 4.

[0163] [Table 4] Anion exchangers Regeneration rate Example 9 Monolithic anion exchanger >90%* Example 10 Monolithic anion exchanger >90%* Example 11 Anion exchange resin 65% Example 12 Anion exchange resin 55% *: In the table, ">90%" means 90% or more.

[0164] As can be seen from Table 4, in Examples 9 to 12, by contacting an aqueous solution of quaternary ammonium hydroxide while changing the ionic form of the anion exchanger, the ionic form of the anion exchanger can be easily and quickly changed to the OH form at a high rate while suppressing the residue of various metals. [Industrial applicability]

[0165] According to the present invention, a method for easily and quickly changing the ionic form of anion exchanger to the OH form at a high rate while suppressing the residue of various metals, and a method for manufacturing anion exchangers are provided.

[0166] 1: Skeletal phase 2: Porous phase 3: Container 4: slot 5: Storage slot 10: Structure P: Pump S: Aqueous solution of quaternary ammonium hydroxide W: Discharge fluid A: Anion exchanger C: Cation exchanger

Claims

1. A method for changing the ionic form of an anion exchanger, characterized in that: in order to change the ionic form of the anion exchanger, the anion exchanger is brought into contact with an aqueous solution of quaternary ammonium hydroxide by passing the aqueous solution of quaternary ammonium hydroxide through a liquid space velocity (SV) of 300-4000 h⁻¹ to the anion exchanger, wherein the anion exchange system is a monolithic organic porous anion exchanger.

2. The method for changing the ionic form of the anion exchanger as described in claim 1, wherein, The quaternary ammonium hydroxide is selected from one or more compounds represented by the following general formula (I): In the formula, R1 to R4 may each be a hydrocarbon group with 1 to 4 carbon atoms having a hydroxyl group, and they may be the same or different from each other.

3. The method for changing the ionic form of the anion exchanger as described in claim 1, wherein, The concentration of the quaternary ammonium hydroxide in the aqueous solution is 0.1–2.0 N.

4. The method for changing the ionic form of the anion exchanger as described in claim 1 involves contacting the anion exchanger with an inorganic acid, then washing it with water, and finally contacting it with an aqueous solution of the quaternary ammonium hydroxide.

5. The method for changing the ionic form of the anion exchanger as described in claim 1 involves contacting the anion exchanger with an inorganic acid, then washing it with water, then contacting it with hydrochloric acid, then washing it with water again, and finally contacting it with an aqueous solution of the quaternary ammonium hydroxide.

6. A method for changing the ionic form of anion exchanger as described in claim 1, wherein, This monolithic organic porous anion exchange system has a continuous structure, which consists of: a three-dimensional continuous framework with an average particle size of 1-60 μm in the dry state, composed of aromatic vinyl polymers containing 0.1-5.0 mol% of cross-linked structural units in all constituent units; and three-dimensional continuous pores with an average diameter of 10-200 μm in the dry state between the frameworks. The total pore volume in the dry state is 0.5-10 mL / g, it has anion exchange groups, and the anion exchange capacity per unit volume in the water-wet state is 0.2-1.0 mg equivalents / mL (water-wet state), and the anion exchange groups are uniformly distributed in the organic porous anion exchanger.

7. A method for changing the ionic form of anion exchanger as described in claim 1, wherein, In order to change the ionic form of an anion exchanger used in the purification of ultrapure water or pharmaceutical solutions, or to change the ionic form of an anion exchanger used in the analysis of anionic impurities in ultrapure water or pharmaceutical solutions, the anion exchanger is brought into contact with an aqueous solution of quaternary ammonium hydroxide.

8. A method for manufacturing an anion exchanger, characterized in that: in order to change the ionic form of the anion exchanger, the anion exchanger is brought into contact with an aqueous solution of quaternary ammonium hydroxide by passing the aqueous solution of quaternary ammonium hydroxide through a liquid space velocity (SV) of 300 to 4000 h⁻¹ relative to the anion exchanger, wherein the anion exchange system is a monolithic organic porous anion exchanger.

Images