WO2015016103A1 - Adsorbent material and method for producing same - Google Patents

Abstract

Provided are: an adsorbent material able to efficiently adsorb an adsorption subject such as a metal ion; and a method for producing such an adsorbent material. The adsorbent material is such that an ethylene-vinyl alcohol copolymer is the substrate, a (meth)acrylate ester skeleton is a structural unit as a graft chain to the substrate, and a polymer component (P₁) having an adsorbent functional group is introduced and the polymer component (P₁) is cross-linked. Also, such an adsorbent material for example may have a degree of swelling indicated by the belowmentioned formula (I) on the order of 50-200%: degree of swelling = {(mass of adsorbent material after shaking for 10 minutes in hot water at 70°C, causing hydration) - (absolute dry mass of hydrated adsorbent material)}/(absolute dry mass of hydrated adsorbent material)×100% …(I).

Description

Adsorbent and method for producing the same

The present invention relates to an adsorbent capable of efficiently adsorbing an object to be adsorbed such as metal ions and a method for producing the same.

In recent years, an adsorption method in which separation and recovery using a chelate resin or the like is known when collecting noble metals, removing harmful metal ions, or separating and purifying high-molecular substances such as proteins.

In the case of a chelate resin, affinity with water can be improved and a metal can be adsorbed effectively by using a polymer having a highly polar structure as a base material.

For example, Patent Document 1 discloses a noble metal ion scavenger that introduces a chelating functional group in a polymer having a crosslink between chitosan molecules. In this scavenger, since the molecular skeleton has a cross-linked structure, it is not dissolved in an acidic solution suitable for adsorption of noble metal ions, and a functional group having a chelating ability is bonded.

Furthermore, Patent Document 2 discloses a chelate ion-adsorbing membrane produced by introducing a chelate-forming group into a graft copolymer membrane obtained by graft copolymerizing glycidyl methacrylate and a crosslinking agent on a porous membrane. ing. Such chelate-type ion-adsorbing films are used for removing metal ions and are described as having excellent performance in elution resistance, chemical durability, and throughput.

Patent Document 3 discloses a cation adsorbent in which ion exchange groups are introduced by graft polymerization of styrene sulfonate in one step on a sheet-like, film-like, or fiber-like organic polymer substrate. Has been. This document also describes that a graft-crosslinked structure can be obtained by coexisting a polyfunctional monomer during graft polymerization.

Furthermore, Patent Document 4 discloses a crosslinked copolymer particle which is based on a copolymer of glycidyl methacrylate and a crosslinking agent and swells significantly in water. This document describes that the crosslinked copolymer particles are useful for separating high molecular substances such as proteins.

Japanese Patent No. 3236363 Japanese Patent No. 3312634 JP 2008-296155 A Japanese Patent No. 3096097

However, the adsorbent based on a polymer having a structure with high polarity described in Patent Documents 1, 2, and 4 has remarkable resin swelling when it contains water because of its high hydrophilicity.
In Patent Document 3, since the styrene skeleton is present in the graft chain, the matrix is hydrophobic, and once dried, the original adsorption performance is not exhibited.

In addition, when the adsorbent is packed in a column or the like, a particle shape having a high bulk density is preferable. However, in the case of the particle shape, the change in the bulk density due to swelling is remarkable, and the adsorption capacity per unit volume is increased. A high degree of swelling control is required to keep it high.
Furthermore, since a highly hydrophilic adsorbent has a large volume fluctuation due to an external factor such as an exposed temperature, there is a concern that the resin swells in a use environment and a problem such as column breakage occurs.

The present invention has been made to solve the above problems, and provides an adsorbent having a hydrophilic skeleton and having a controlled swelling property derived from a crosslinked structure, and such an adsorbent. It aims at providing the manufacturing method of.

The inventors of the present invention have intensively studied to achieve the above object, and as a result, (i) in the prior art, when efficiently recovering an object to be adsorbed such as metal ions, attention is paid to the recovery efficiency as a single adsorbent. However, research is focused on improving hydrophilicity to increase the adsorption efficiency and increasing the amount of adsorbed functional groups introduced. However, when actually using the adsorbent, the adsorbent itself swells. It has been noticed that, in conjunction with the increase in the property, the packing efficiency of the adsorbent itself when packed in a closed space such as a column is lowered. Furthermore, (ii) when recovering an adsorbed material such as metal ions, a high-temperature operation may be required, but it has been found that the swellability of the adsorbent increases at a high temperature, leading to breakage of the column and the like.

As a result of further research, (iii) the base material is an ethylene-vinyl alcohol copolymer that is a hydrophilic polymer, and a hydrophilic (meth) acrylic acid ester skeleton is formed on the base material. Introducing a polymer component having an adsorptive functional group as a structural unit as a graft chain, and further crosslinking the polymer component makes it possible to suppress the swelling while maintaining the adsorptivity, and (iv) increase the packing efficiency In addition to improving the recovery efficiency of the adsorbent as a whole, (v) the final form of the polymer is crosslinked so that the adsorbent can be used even when a heating solvent is applied. (Vi) By efficiently managing the swellability of the adsorbent under such high-temperature conditions, the work of recovering the adsorbent such as metal ions can be performed efficiently. It found that it has led to the present invention.

That is, the first embodiment of the present invention is a polymer having an ethylene-vinyl alcohol copolymer as a base material, a polymer having an adsorption functional group having a (meth) acrylate skeleton as a structural unit as a graft chain on the base material. An adsorbent in which component P ₁ is introduced and the polymer component P ₁ is crosslinked.
Such an adsorbent may have a swelling degree represented by the following formula (I) of 50 to 200%, for example.
Swelling degree = {(mass after the adsorbent is shaken in hot water at 70 ° C. for 10 minutes to contain water) − (absolute dry mass of the adsorbed adsorbent)} / (absorption of the adsorbed adsorbent) (Dry mass) x 100 (%) (I)

The cross-linking component may have, for example, any one or more functional groups selected from the group consisting of amino groups, isocyanate groups, epoxy groups, carbodiimide groups, and azetidinium groups.

In the adsorbent, the adsorbing functional group is a glucamine group, a diol group, a polyol group, a group composed of a polyol and a nitrogen atom, an iminodiacetic acid group, an amino group, an ammonium group, an amidoxime group, a dithiocarbamic acid group, a thiourea group, It may be any one or more functional groups selected from the group consisting of an isothiourea group, a phosphoric acid group, and a phosphonic acid group.

The adsorbent may be a porous body. In the case of a porous body, the average value of the long diameters of the pores formed on the surface of the porous body may be in the range of 0.01 μm to 20 μm.

The adsorbent may be in the form of particles, for example, in which case the particle diameter range of the adsorbent may be about 10 to 2000 μm.

A second embodiment of the present invention is a method for producing the adsorbent,
Preparing an ethylene-vinyl alcohol copolymer as a base component;
A polymer component introduction step of introducing a polymer component P ₀ having a reactive (meth) acrylate skeleton as a structural unit into the base material component as a graft chain;
An adsorption functional group introduction step of introducing an adsorption functional group to the polymer component P ₀ , having a (meth) acrylate skeleton as a structural unit, and obtaining a polymer component P ₁ having an adsorption functional group;
A crosslinking step of crosslinking the polymer component P ₀ or P ₁ ;
Is a method for producing an adsorbent comprising at least

In the above manufacturing method, the polymeric component P ₀ may be provided with a graft chain introduction step is introduced as a graft chain to the substrate component. In this case, ionizing radiation may act on the substrate component to introduce a graft chain.

In the polymer component introduction step, the graft ratio of the graft chain introduced may be, for example, 30 to 900% by mass from the viewpoint of improving the adsorptivity to the adsorbed material.
In adsorptive functional group introduction step, adsorptive functional group concentration in the complex of the polymeric component P ₁ and the substrate component is preferably in the range from 1.5 mmol / g or more.

In the adsorbent of the present invention, since the swelling property of the resin is controlled by the crosslinking treatment while using a highly hydrophilic skeleton as a base material, the swelling property is low while maintaining high adsorption performance, and the metal ions and the like are efficiently covered. The adsorbate can be recovered. Moreover, in the manufacturing method of the adsorbent of this invention, the adsorbent which has the above outstanding performances can be manufactured efficiently.

Hereinafter, embodiments of the present invention will be described in detail. Note that the embodiments described below do not limit the present invention.

In the first embodiment of the present invention, a polymer component P having an ethylene-vinyl alcohol copolymer as a base material, a (meth) acrylate skeleton as a structural unit as a graft unit on the base material, and an adsorptive functional group. ₁ is an adsorbent in which ₁ is introduced and the polymer component P ₁ is crosslinked.
A second embodiment of the present invention is a method for producing the adsorbent,
Preparing an ethylene-vinyl alcohol copolymer as a base component;
A polymer component introduction step of introducing a polymer component P ₀ having a reactive (meth) acrylate skeleton as a structural unit into the base material component as a graft chain;
The introducing adsorptive functional group on the polymer component P _0, and (meth) which has an acrylic acid ester skeleton as a structural unit, the functional group introduced to obtain a polymer component P ₁ having an adsorbing functional group,
A crosslinking step of crosslinking the polymer component P ₀ or P ₁ ;
At least.
While maintaining the hydrophilicity of the adsorbent, it suppresses the swellability of the adsorbent while maintaining the adsorptivity to the adsorbent by suppressing the mobility of the polymer chain that will be the final form by crosslinking. be able to.

(Base material component)
The adsorbent of the present invention contains an ethylene-vinyl alcohol copolymer as a base component. An ethylene-vinyl alcohol copolymer is suitable as a base material for an adsorbent because it has high hydrophilicity, excellent moldability, and excellent acid resistance.

For example, the ethylene content of the ethylene-vinyl alcohol copolymer may be about 10 to 60 mol%, preferably about 20 to 50 mol%. If the ethylene content is too low, the water resistance of the resulting graft copolymer may be reduced. On the other hand, when there is too much ethylene content, manufacture is difficult and acquisition is difficult.

The saponification degree of the ethylene-vinyl alcohol copolymer is preferably 90 mol% or more, more preferably 95 mol% or more, and particularly preferably 99 mol% or more. When the degree of saponification is too low, moldability may be deteriorated or the water resistance of the obtained graft copolymer may be lowered.

Further, the melt flow rate (MFR) (210 ° C., load 2160 g) of the ethylene-vinyl alcohol copolymer is not particularly limited, but is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more. preferable. If the melt flow rate is too small, water resistance and strength may be reduced. In addition, the upper limit of a melt flow rate should just be the range normally used, for example, may be 25 g / 10min or less.

The ethylene-vinyl alcohol copolymer of the present invention may contain other unsaturated monomer units as long as the effects of the present invention are not impaired. The content of the unsaturated monomer unit is preferably 10 mol% or less, more preferably 5% mol or less.
Such ethylene-vinyl alcohol copolymers can be used alone or in combination of two or more.

The surface shape of the base material component is not particularly limited as long as graft polymerization is possible. From the viewpoint of improving the reactivity during graft polymerization, it is preferably a porous body that has been previously made porous. The porous body only needs to have a plurality of holes formed on at least the surface thereof, and does not need to have holes formed therein. Preferably, the porous body has a structure including at least 10, preferably 100 or more, more preferably 1,000 or more pores having a major axis of 0.01 μm to 20 μm per 1 cm ^{2 of} area. May be.

The porous base material component may physically form pores with respect to the base material component, or may be prepared by melting and mixing with a pore forming agent such as a foaming agent and the base material, or a solvent. The polymer may be extracted by mixing by melt kneading or the like, and then the solvent extractable polymer may be extracted.

The pores formed on the surface of the porous body may have an average length of about 0.01 μm to 20 μm, preferably about 0.05 μm to 10 μm, more preferably about 0.1 μm to 5 μm. May be. The average value of the major axis of these pores is a value measured by the method described in the examples described later.

In particular, a porous base material component made porous using a solvent-soluble polymer component is preferable in that the pore size can be easily controlled. For example, when preparing a porous substrate component using a solvent-soluble polymer component, from the viewpoint of controlling the size of the pores, the substrate component and the solvent-soluble polymer component are mixed by melt-kneading, etc. It is preferably formed by a step of obtaining a composite obtained by cooling and solidifying a melt and a step of extracting a solvent-soluble polymer component from the composite with a solvent.
In the present invention, “cooling and solidifying a melt” means cooling and solidifying the melt without using a solidification bath or the like.

The solvent-soluble polymer used in the present invention is not particularly limited as long as it can be melt-mixed with the ethylene-vinyl alcohol copolymer, and is an organic solvent-soluble polymer (for example, polystyrene) or an alkali-soluble polymer (for example, polyester). Or the like, and is preferably a water-soluble polymer. The water-soluble polymer is not particularly limited as long as it can be melt-mixed with the ethylene-vinyl alcohol copolymer, and generally known water-soluble polymers can be used. Examples of the water-soluble polymer include starch; gelatin; cellulose derivatives; water-soluble amine-based polymers such as polyvinylamine and polyallylamine; polyacrylic acid; polyacrylamide such as polyisopropylacrylamide; polyvinylpyrrolidone; Among these, polyvinyl alcohol is particularly preferably used because it is excellent in melt kneading with an ethylene-vinyl alcohol copolymer and easily controls the voids.

The ratio (mass ratio) between the base material component and the solvent-soluble polymer component can be appropriately determined according to the required degree of porosity. For example, the base material component: solvent-soluble polymer component is 100 : About 0 to 20:80, and preferably about 100: 0 to 30:70.

For example, polyvinyl alcohol used as a water-soluble polymer can have structural units other than vinyl alcohol units and structural units derived from vinyl ester monomers as long as the effects of the present invention are obtained. The structural unit includes, for example, α-olefins such as ethylene, propylene, n-butene, isobutylene and 1-hexene; acrylic acid and salts thereof; methyl acrylate, ethyl acrylate, N-propyl acrylate, acrylic acid i Unsaturated monomers having an acrylate group such as -propyl, N-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate; methacrylic acid And salts thereof; methyl methacrylate, ethyl methacrylate, N-propyl methacrylate, i-propyl methacrylate, N-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, methacrylic acid Dodecyl, octadecyl methacrylate, etc. Unsaturated monomer having a methacrylic acid ester group; acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid and its salt, acrylamidopropyldimethylamine and its salt (For example, quaternary salt); methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and its salt, methacrylamidepropyldimethylamine and its salt (for example, quaternary salt); methyl vinyl ether, ethyl Vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether Vinyl ethers such as ether, stearyl vinyl ether and 2,3-diacetoxy-1-vinyloxypropane; vinyl cyanides such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride and vinyl fluoride; vinylidene chloride, fluorine Vinylidene halides such as vinylidene halide; allyl compounds such as allyl acetate, 2,3-diacetoxy-1-allyloxypropane, allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid, fumaric acid, and salts or esters thereof A vinylsilyl compound such as vinyltrimethoxysilane and isopropenyl acetate. The content of the structural unit is less than 10 mol%.

The viscosity average polymerization degree (measured in accordance with JIS K6726) of the polyvinyl alcohol used in the present invention is not particularly limited, but is preferably 100 to 10,000, more preferably 200 to 7,000, still more preferably. Is 300 to 5,000. If the viscosity average degree of polymerization deviates from the above range, the surface area of the resulting porous body may be reduced.

The saponification degree of the polyvinyl alcohol used in the present invention is not particularly limited, but is preferably 50 mol% or more, more preferably 60 to 98 mol%, and particularly preferably 70 to 95 mol%. If the degree of saponification is too low, the water solubility is lowered and the extractability after molding becomes worse. Polyvinyl alcohol having a too high degree of saponification is difficult to melt and mix.

As described above, the porous ethylene-vinyl alcohol copolymer used in the present invention is, for example, mixed by melt-kneading an ethylene-vinyl alcohol copolymer and a solvent-soluble polymer (preferably a water-soluble polymer). Then, after obtaining a composite (compound) in which the melt is cooled and solidified, a solvent-soluble polymer (preferably a water-soluble polymer) is extracted from the composite. The method of melt kneading is not particularly limited, and a known kneader such as a single screw extruder, a twin screw extruder, a Brabender, or a kneader can be used. In order to obtain a target shape, pulverization or the like may be performed at each stage as necessary.

Further, as long as the solvent-soluble polymer can be extracted without dissolving the ethylene-vinyl alcohol copolymer, the solvent used for the extraction is not particularly limited, and water, various organic solvents, water and organic solvents A mixture or the like can be used, but when a water-soluble polymer is used, it is preferable to use water, particularly hot water, as the solvent. The temperature of hot water is preferably 40 ° C to 120 ° C, more preferably 50 ° C to 100 ° C.

(Graft chain forming step)
Prior to the functional group-introducing step, the base material component, by performing a graft chain formation step of introducing a polymer component P ₀ as a graft chain, it is possible to obtain a graft copolymer.

(Graft chain introduction treatment)
As a method for introducing the polymer component P ₀ as a graft chain into the base material component described above, various known methods are possible. For example, the graft chain can be obtained by utilizing radical polymerization using a polymerization initiator. And a method of generating a radical with respect to a base material component using ionizing radiation and introducing a graft chain. Among these, from the viewpoint of high graft chain introduction efficiency, a method of introducing the polymer component P ₀ as a graft chain using ionizing radiation is preferably used.

(Polymer component P ₀ production process)
The polymer component P ₀ is a radical addition polymerization of a reactive (meth) acrylate skeleton (hereinafter sometimes referred to as a reactive (meth) acrylate skeleton) monomer from a radical generated in the base component. Can be obtained.

Examples of the reactive (meth) acrylic acid ester skeleton include a skeleton in which a functional group (that is, a functional group having reactivity with an adsorbing functional group) is introduced into the alkoxy group in the (meth) acrylic acid ester. Examples of such a skeleton include glycidyl (meth) acrylate, glyceryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, chloroethyl (meth) acrylate, and 3-chloro-2-hydroxypropyl (meth) acrylate. Can be mentioned. These reactive (meth) acrylic acid ester skeletons may be used alone or in combination of two or more.

In addition to the reactive (meth) acrylate skeleton, the polymer component P ₀ requires other vinyl polymerizable monomers (for example, (meth) acrylate monomers in which no reactive group is introduced). It may be included accordingly. Further, as described later, when a cross-linked structure is introduced in the formation process of the polymer component P ₀ , a structure derived from the cross-linked component may be included.

The polymer component P ₀ is preferably composed of a (meth) acrylic acid ester skeleton having a highly reactive functional group at its terminal. In this case, the reactive functional group present in the skeleton is described later. The adsorbing functional group can be easily introduced.

Examples of the ionizing radiation include α rays, β rays, γ rays, accelerated electron rays, ultraviolet rays, and the like. Practically, accelerated electron rays or γ rays are preferable.

As a method of graft polymerization of unsaturated monomer to the base material component using ionizing radiation, simultaneous irradiation method in which the base material component and unsaturated monomer coexist and irradiate with radiation, only the base material component is used. Although any of the pre-irradiation methods in which the unsaturated monomer and the substrate component are brought into contact with each other after irradiation with radiation in advance is possible, the pre-irradiation method has a feature that it is difficult to generate side reactions other than graft polymerization.

The unsaturated monomer used here includes, in addition to the monomer forming the reactive (meth) acrylate skeleton described above, other vinyl polymerizable monomers ((meth) acrylate esters as necessary). As such) and multifunctional monomers. Polyfunctional monomers may be used in the case of introducing a crosslinked structure in the formation process of the polymer components P _0. As the polyfunctional monomer, for example, divinylbenzene, methylenebisacrylamide, polyethylene glycol dimethacrylate and the like are preferably used.

In the structural unit forming the polymer component P ₀ , the other vinyl polymerizable monomer may be contained in an amount of, for example, 50 mol% or less, preferably 30 mol% or less, and the polyfunctional monomer is, for example, It may be contained in an amount of 50 mol% or less, preferably 30 mol% or less.

In the graft polymerization, the base component and the unsaturated monomer may be brought into contact with each other as a liquid phase graft polymerization method in which a liquid unsaturated monomer or an unsaturated monomer solution is brought into direct contact with the unsaturated monomer solution. There are vapor-phase graft polymerization methods in which the monomer vapor or vaporized contact is made, but it can be selected according to the purpose. In the liquid phase graft polymerization method and the gas phase graft polymerization method, the reaction conditions such as the concentration of the unsaturated monomer to be contacted and the polymerization treatment time can be appropriately set by those skilled in the art depending on the required graft rate and the like. it can.

The dose of ionizing radiation is not particularly limited, but is preferably 5 to 230 kGy, more preferably 10 to 190 kGy, still more preferably 15 to 140 kGy, and most preferably 20 to 120 kGy. If the dose is too small, the graft rate may decrease and the desired adsorption capacity may not be obtained. When the dose is too high, there is a concern that the treatment process is costly and the resin deteriorates during irradiation.

The amount of the unsaturated monomer introduced by graft polymerization (graft ratio) is not particularly limited, but is preferably, for example, 30 to 900 parts by mass (30 to 900%) with respect to 100 parts by mass of the base material. It is more preferably 60 to 800 parts by mass (60 to 800%), further preferably 120 to 700 parts by mass (120 to 700%), and 150 to 700 parts by mass (150 to 700%). Is more preferably 200 to 600 parts by mass (200 to 600%). If the graft rate is too small, the adsorption performance to the adsorbed material such as metal ions is often insufficient. When the graft rate is too high, synthesis is generally difficult. In addition, a graft rate shows the value measured by the method described in the Example mentioned later.

[Functional group introduction step]
First, in the functional group introduction step, an adsorptive functional group is introduced into the polymer component P ₀ having at least a reactive (meth) acrylate skeleton as a structural unit.

(Polymer component P ₁ production process)
The polymer component P ₁ can be obtained by introducing an adsorptive functional group to the polymer component P ₀ obtained as described above. A compound having an adsorptive functional group may be dissolved in a good solvent of this compound and brought into contact with the polymer component P ₀ and reacted, and the reaction conditions such as the compound concentration and reaction time are the types of the polymer component P ₀ . Depending on the amount of adsorbed functional group introduced, it can be appropriately selected by those skilled in the art.

The polymer component P ₁ has a (meth) acrylic acid ester skeleton as a structural unit, and has an adsorptive functional group having an adsorptivity to an adsorbent, and thus has a highly polar structure, It becomes a polymer with excellent affinity.

The adsorptive functional group to be introduced into the polymer component P ₁ can be selected according to the type of the target adsorbate, and is, for example, a chelate-forming group because of its high adsorptivity to metal ions. Glucamine group, diol group, polyol group, group composed of polyol and nitrogen atom, iminodiacetic acid group, amino group, ammonium group, amidoxime group, dithiocarbamic acid group, thiourea group, isothiourea group, phosphoric acid group, phosphonic acid Groups and the like are preferred. These adsorbing functional groups may be used alone or in combination of two or more. The adsorbing functional group may be a functional group introduced by, for example, hydrolysis of a reactive functional group.

From the viewpoint of satisfying both low swelling improvements and resin adsorption capacity, the complex of polymeric components P ₁ and the substrate the above components, for example, there adsorptive functional group is 1.5 mmol / g or more It may be. Preferably, 2.0 mmol / g or more, more preferably 3.0 mmol / g or more may be introduced.
The upper limit can be set as appropriate, but may be about 30 mmol / g from the viewpoint of suppressing swelling. The amount of the adsorbing functional group indicates a value measured by the method described in Examples described later.

[Crosslinking process]
In the crosslinking step, the polymer component P ₀ or P ₁ can be crosslinked.
For example, a monomer case, as described above, to form in the step of forming the polymeric component P _0, with a reactive (meth) acrylic ester backbone of performing crosslinking treatment (I) relative to the polymer component P ₀ By using both of the polyfunctional monomers, a crosslinked structure can be introduced into the polymer component P ₀ .

On the other hand, when performed on the polymer component P ₁ crosslinking processes (II), relative to the polymer component P ₁ of adsorptive functional group is introduced by applying a crosslinking agent, a polymer component P _{1 (e.g.,} A part of the adsorptive functional group) can be crosslinked by a crosslinking component.
The cross-linking component may cross-link a part of the adsorptive functional group and cross-link groups other than the other adsorptive functional group in the graft copolymer.

By carrying out the cross-linking treatment, while maintaining the hydrophilicity of the adsorbent, it suppresses the mobility of the polymer chain that will be the final form, so that the adsorbent swells while adsorbing to the adsorbent. Can be kept low.

As in the case of the crosslinking treatment (I), in the technique in which a divinyl compound is present as a copolymerization component at the time of radical polymerization of the vinyl compound and the crosslinking treatment is performed simultaneously with the polymerization, the polymerization control is difficult depending on the polymerization method and the shape of the adsorbent to be obtained. Since there is a possibility of inducing problems such as gelation, the method of crosslinking the adsorption functional group of the polymer component P ₁ by the crosslinking treatment (II) is more preferable. Hereinafter, the crosslinking treatment (II) will be described in detail.

In the crosslinking treatment (II), the polymer component P ₁ is preferably treated by being immersed and stirred in a treatment solution in which a crosslinking agent is dissolved or dispersed.
From the viewpoint of maintaining the swellability of the entire adsorbent while maintaining the adsorptive properties by the adsorptive reactive groups, the concentration, temperature, liquid volume and treatment time of the crosslinking treatment liquid having a crosslinking agent are determined based on the polymer component P ₁ (and necessary Depending on the kind of the base material component to be added according to the above, it can be appropriately set. The solvent is not particularly limited, and a solvent in which the crosslinking agent is easily dissolved or dispersed can be selected as appropriate. However, an aqueous solvent (particularly water) is preferably used because post-treatment is easy.

Depending on the type of the crosslinking agent, the reaction temperature can be appropriately set.For example, from the viewpoint of improving the reaction rate and allowing the swelling property of the polymer after the addition reaction to be in an appropriate range, for example, The temperature for performing the crosslinking treatment may be, for example, about 30 to 100 ° C., preferably about 35 to 90 ° C.

Various cross-linking agents can be used as long as they have cross-linkability to the adsorptive functional group. For example, cross-linking agents having any one or more of amino group, isocyanate group, epoxy group, carbodiimide group, and azetidinium group ( Or a crosslinking component). Among these, azetidinium group, isocyanate group, amino group, epoxy group and the like are particularly preferably used because of excellent reactivity with general adsorption functional groups. A crosslinking agent may be used individually by 1 type, and may use 2 or more types together.

Examples of the crosslinking agent having an amino group include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, isophoronediamine, 1,3-bisaminomethylcyclohexane. Diamine compounds such as diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, dicyandiamide; diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, polyvinylamine, polyallylamine, polyethyleneimine, polyamidoamine Polyamine compounds such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, 1,3 Bis (hydrazinocarboethyl) -5-isopropyl hydantoin, polyacrylic acid hydrazide, and hydrazine compounds such as hydrazine carbonate is.

As a crosslinking agent having an isocyanate group, “Duranate” manufactured by Asahi Kasei Chemicals Corporation (WB40-100, WB40-80D, WE50-100, WT30-100, WT20-100, etc.); Tolylene diisocyanate (TDI); Hydrogenated TDI Trimethylolpropane-TDI adduct (for example, “DesmodurL” manufactured by Bayer); triphenylmethane triisocyanate; methylenebisdiphenyl isocyanate (MDI); hydrogenated MDI; polymerized MDI; hexamethylene diisocyanate; xylylene diisocyanate; -Dicyclohexylmethane diisocyanate; isophorone diisocyanate and the like. Isocyanates dispersed in water using an emulsifier can also be used.

Examples of the crosslinking agent having an epoxy group include “Denacol” (EX-611, EX-612, EX-614, EX-614B, EX-622, EX-512, EX-521, EX-411, manufactured by Nagase ChemteX Corporation. , EX-421, EX-313, EX-314, EX-321, EX-201, EX-211, EX-212, EX-252, EX-810, EX-811, EX-850, EX-851, EX -821, EX-830, EX-832, EX-841, EX-861, EX-911, EX-941, EX-920, EX-931, EX-721, EX-203, EX-711, EX-221 Etc.), bisphenol A diglycidyl ether, bisphenol A diβ methyl glycidyl ether, bisphenol F diglycidyl ether , Tetrahydroxyphenylmethane tetraglycidyl ether, resorcinol diglycidyl ether, brominated bisphenol A diglycidyl ether, chlorinated bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, diglycidyl ether of bisphenol A alkylene oxide adduct, novolak Glycidyl ether type such as glycidyl ether, polyalkylene glycol diglycidyl ether, glycerin triglycidyl ether, pentaerythritol diglycidyl ether, epoxy urethane resin; glycidyl ether ester type such as p-oxybenzoic acid glycidyl ether; ester; diphthalic acid Glycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydro Glycidyl ester types such as phthalic acid diglycidyl ester, acrylic acid diglycidyl ester, dimer acid diglycidyl ester; glycidyl amine types such as glycidyl aniline, tetraglycidyl diaminodiphenylmethane, triglycidyl isocyanurate, triglycidyl aminophenol; epoxidized polybutadiene, Linear aliphatic epoxy resins such as epoxidized soybean oil; 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl (3,4 Epoxycyclohexane) carboxylate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, vinylcyclohexene diepoxide, dicyclopentadiene oxide , Bis (2,3-epoxy cyclopentyl) ether, alicyclic epoxy resins such as limonene oxide.

Examples of the crosslinking agent having a carbodiimide group include “Carbodilite” (SV-02, V-02, V-02-L2, V-04, E-01, E-02) manufactured by Nisshinbo Chemical Co., Ltd.

Examples of the crosslinking agent having an azetidinium group include polyamide / epichlorohydrin resin, polyamine / epichlorohydrin resin, and the like, for example, manufactured by Seiko PMC Co., Ltd. (WS4002, WS4020, WS4024, WS4030, WS4046, WS4010, CP8970). ) And the like.

(Adsorbent)
The adsorbent of the present invention has an ethylene-vinyl alcohol copolymer as a base material, and a polymer component P ₁ having a (meth) acrylate skeleton as a structural unit as a graft unit and having an adsorptive functional group is introduced into the base material. are, the polymer component P ₁ is crosslinked by a crosslinking component.

Preferably, the degree of swelling represented by the following formula (I) may be, for example, 50 to 200% from the viewpoint of controlling swelling under hot water while maintaining affinity with water.
Swelling degree = {(mass after the adsorbent is shaken in hot water at 70 ° C. for 10 minutes to contain water) − (absolute dry mass of the adsorbed adsorbent)} / (absorption of the adsorbed adsorbent) (Dry mass) x 100 (%) (I)
Preferably, the degree of swelling is 150% or less, more preferably 130% or less. The degree of swelling is preferably 60% or more, and more preferably 70% or more. In addition, this swelling degree shows the value measured by the method described in the Example mentioned later.

In the formula (I), the reason for swelling the adsorbent with hot water of about 70 ° C. is as follows. That is, in the adsorption and recovery operation, it may be brought into contact with a high-temperature medium such as hot water, and the resin is most easily swollen during the operation. For this reason, it is important to control the swelling characteristics at high temperatures from the viewpoint of improving the adsorption and recovery efficiency.

(Adsorbent shape)
The shape of the adsorbent of the present invention is not particularly limited, depending on the application location, from various shapes such as fibers and aggregates of woven and knitted fabrics and nonwoven fabrics, particles, sheets, hollow fibers, and films or processed products thereof. You can choose. Among these, the particles are preferably in the form of particles from the viewpoint of improving the adsorptivity with an object to be adsorbed such as metal ions and being easily packed in a closed space such as a column. When it is particulate, the adsorbent may be spherical or non-spherical (for example, irregularly shaped particles).

When the adsorbent is in the form of particles, it may be appropriately adjusted to the desired particle size by pulverization or the like, but the particle size is preferably 10 μm to 2000 μm, more preferably 30 μm to 1500 μm, and most preferably 40 μm to 1000 μm. When the particle diameter is 10 μm or less, it is difficult to handle because the fine powder is likely to fly. When the particle size is 2000 μm or more, sufficient adsorption performance may not be obtained. In addition, a particle diameter shows the value classified by sieving.

The adsorbent may be a porous body. In this case, the pores formed on the surface may have an average value of the major axis of about 0.01 μm to 20 μm, preferably 0.05 μm to It may be about 10 μm, more preferably about 0.1 μm to 5 μm, still more preferably about 0.2 μm to 5 μm. The average value of the major axis of these pores is a value measured by the method described in the examples described later.

The adsorbent of the present invention may contain various additives such as inorganic fine particles, light stabilizers, antioxidants and the like within a range not impairing the effects of the present invention.

The adsorbent of the present invention can adsorb various objects to be adsorbed according to the type of adsorbing functional group, and can then efficiently elute and recover the objects to be adsorbed. Preferred adsorbents include, for example, various metals (for example, platinum group metals, gold, silver, copper, nickel, chromium, vanadium, cobalt, lead, zinc, etc.) or valuable metals from solutions containing these metal compounds. It can be used for recovery and removal of harmful metals (for example, mercury, cadmium, etc.) contained in factory wastewater, mine wastewater, hot spring water, and the like.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[Swelling degree]
0.3 g of dried particles was added to 20 g of hot water at 70 ° C. and shaken at 100 rpm for 10 minutes. The particles were collected by filtration and the water adhering to the surface was wiped off, and then the mass of the water-containing particles was measured. Thereafter, the particles were dried in a vacuum dryer at 40 ° C. for 24 hours, and the mass of the absolutely dry particles was measured. Calculation was performed according to the following formula.
Swelling degree [%] = {(hydrous particle mass [g]) − (absolute dry particle mass [g])} / (absolute dry particle mass [g]) × 100

[Calculation method of adsorption functional group]
Let W be the mass change before and after the reaction for introducing the adsorptive functional group. Calculation was performed according to the following formula.
Adsorption functional group amount [mmol / g] = {(Number of adsorption functional groups possessed by reaction substrate) × (W [g] / reaction substrate molecular weight [g / mol]) × 1000} / resin particle mass after reaction [g]

[Graft ratio]
Calculation was performed according to the following formula.
Graft ratio [%] = 100 × {(weight of graft body after reaction) − (base resin weight before reaction)} / (base resin weight before reaction)

[Pure resin]
Calculation was performed according to the following formula.
Resin purity [g] = hydrous resin weight [g] × solid content concentration [mass%] / 100
In addition, solid content concentration is the value calculated | required from the dry weight after weighing | cleaning water-containing resin 0.2g and making it dry with a 100 degreeC hot air dryer for 6 hours.

[Calculation of average value of major axis of pores]
The dry particle surface was observed using a scanning electron microscope. Arbitrary 50 pores were selected from the pores formed on the surface, and the major axis of each pore was measured. The 50 major axes were averaged to derive an average value. However, in the case of 1 nm or less, since it cannot be distinguished from scratches, deposits, etc., it was excluded from the selection. The dried particles were prepared by drying at 100 ° C. for 3 hours with a hot air dryer.

[Cu adsorption test]
The adsorbent was immersed in ion-exchanged water and shaken at room temperature for 1 hour to prepare an aqueous dispersion of the adsorbent. The dispersion was added to a graduated cylinder and filled to 0.2 ml (= fill volume). Next, the filled dispersion was filtered and then subjected to centrifugal dehydration at 3000 rpm for 5 minutes to obtain water-containing particles of the adsorbent. The entire amount of the water-containing particles was put into 100 mL of 0.001N sulfuric acid having a Cu concentration of 30 ppm and stirred at 23 ° C. for 1 hour. Thereafter, 1 mL of the supernatant was sampled, diluted 50 times, and then measured with an ICP emission analyzer (IRIS-AP manufactured by Nippon Jarrell Ash). The measured metal concentration was C (ppm), and the metal adsorption rate was determined from the following formula.
Metal adsorption rate = [1− (C × 50/100)] × 100 (%)

[Pt adsorption test]
The adsorbent was immersed in 3N hydrochloric acid and shaken at room temperature for 1 hour to prepare a hydrochloric acid dispersion of the adsorbent. The dispersion was added to a graduated cylinder and filled to 3 ml (= fill volume). Next, the filled dispersion was filtered, washed with water, and then subjected to centrifugal dehydration at 3000 rpm for 5 minutes to obtain water-containing particles of the adsorbent. The entire amount of the water-containing particles was put into 100 mL of 3N hydrochloric acid having a Pt concentration of 100 ppm and stirred at 23 ° C. for 1 hour. Thereafter, 1 mL of the supernatant was sampled, diluted 50 times, and then measured with an ICP emission analyzer (IRIS-AP manufactured by Nippon Jarrell Ash). The measured metal concentration was C (ppm), and the metal adsorption rate was determined from the following formula.
Metal adsorption rate = [1− (C × 50/100)] × 100 (%)

[Example 1]
90 parts by mass of a commercially available ethylene-vinyl alcohol copolymer (Kuraray Co., Ltd., F101) and 10 parts by mass of vinyl alcohol polymer (Kuraray Co., Ltd., PVA205) at a temperature of 210 ° C. using a lab plast mill. Then, the compound obtained by cooling and solidifying the melt was pulverized and classified into particles having a particle diameter of 106 μm to 212 μm using a sieve. Further, the obtained particles were stirred in hot water at 100 ° C. for 2 hours to extract only the vinyl alcohol polymer, thereby obtaining porous ethylene-vinyl alcohol copolymer particles. The average value of the major axis of the pores of the porous particles was 0.27 μm. The porous particles were irradiated with 100 kGy of γ rays, immersed in an isopropanol solution of glycidyl methacrylate substituted with nitrogen at 80 ° C., and stirred for 150 minutes for graft polymerization. Thereafter, the obtained particles were washed with methanol and dried, and the graft ratio was evaluated to be 351%. Further, the particles were immersed in an aqueous disodium iminodiacetate adjusted to 100 ° C. and reacted for 9 hours. After the reaction, the particles were washed with water and dried to obtain an adsorbent complex (polymer complex P1 and substrate component complex) having an iminodiacetic acid group. The amount of functional groups introduced into the adsorptive complex was 4.6 mmol / g, and the degree of swelling before the crosslinking treatment was 445%. The obtained adsorptive complex was immersed in an aqueous solution of polyamide / epichlorohydrin resin (cross-linking agent “WS4020” manufactured by Seiko PMC Co., Ltd.) adjusted to 60 ° C. and reacted for 1 hour. After the reaction, the particles were washed with water and dried to obtain the target adsorbent. The average value of the long diameter of the pores of the adsorbent was 0.21 μm. The obtained adsorbent was classified into particles having a particle diameter of 106 μm to 425 μm using a sieve, and the degree of swelling was evaluated. In addition, a Cu adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

[Example 2]
A commercially available ethylene-vinyl alcohol copolymer (Kuraray Co., Ltd., L104) 80 parts by mass and a vinyl alcohol polymer (Kuraray Co., Ltd., PVA205) 20 parts by mass were tested at a temperature of 210 ° C. using a lab plast mill. Then, the compound obtained by cooling and solidifying the melt was pulverized, and particles having a particle diameter of 212 μm to 425 μm were classified using a sieve. Further, the obtained particles were stirred in hot water at 100 ° C. for 2 hours to extract only the vinyl alcohol polymer, thereby obtaining porous ethylene-vinyl alcohol copolymer particles. The average value of the major axis of the pores of the porous particles was 0.41 μm. The porous particles were irradiated with 30 kGy of γ rays, immersed in an isopropanol solution of glycidyl methacrylate substituted with nitrogen at 80 ° C., and stirred for 90 minutes to carry out graft polymerization. Thereafter, the obtained particles were washed with methanol and dried, and then the graft ratio was evaluated and found to be 258%. Further, the particles were immersed in an aqueous disodium iminodiacetate adjusted to 100 ° C. and reacted for 9 hours. After the reaction, the particles were washed with water and dried to obtain an adsorbent complex having an iminodiacetic acid group. The amount of functional groups introduced into the adsorptive complex was 3.8 mmol / g, and the degree of swelling before the crosslinking treatment was 290%. The obtained adsorptive complex was immersed in an aqueous solution of polyamide / epichlorohydrin resin (cross-linking agent “WS4020” manufactured by Seiko PMC Co., Ltd.) adjusted to 60 ° C. and reacted for 1 hour. After the reaction, the particles were washed with water and dried to obtain the target adsorbent. The average value of the long diameters of the pores of the adsorbent was 0.39 μm. The obtained adsorbent was classified into particles having a particle diameter of 300 μm to 500 μm using a sieve, and the degree of swelling was evaluated. In addition, a Cu adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

[Example 3]
90 parts by mass of a commercially available ethylene-vinyl alcohol copolymer (Kuraray Co., Ltd., F101) and 10 parts by mass of a vinyl alcohol polymer (Kuraray Co., Ltd., PVA403) were heated at 210 ° C. using a lab plast mill. After melt-kneading for 3 minutes at a temperature, the compound obtained by cooling and solidifying the melt was pulverized, and particles having a particle diameter of 212 μm to 425 μm were classified using a sieve. Further, the obtained particles were stirred in hot water at 100 ° C. for 2 hours to extract only the vinyl alcohol polymer, thereby obtaining porous ethylene-vinyl alcohol copolymer particles. The average value of the major axis of the pores of the porous particles was 0.23 μm. The porous particles were irradiated with 60 kGy of γ-rays, immersed in an isopropanol solution of glycidyl methacrylate substituted with nitrogen at 80 ° C., and stirred for 140 minutes for graft polymerization. Thereafter, the obtained particles were washed with methanol and dried, and then the graft ratio was evaluated and found to be 310%. Further, the particles were immersed in an isopropanol solution of ethylenediamine adjusted to 80 ° C. and reacted for 1 hour. After the reaction, the particles were washed with water and dried to obtain an adsorptive complex having an amino group. The amount of functional groups introduced into the adsorbent complex was 6.0 mmol / g, and the degree of swelling before the crosslinking treatment was 258%. The obtained adsorptive complex was immersed in an aqueous ethylene glycol diglycidyl ether solution adjusted to 40 ° C. and allowed to react for 1 hour. After the reaction, the particles were washed with water and dried to obtain the target adsorbent. The average value of the long diameter of the pores of the adsorbent was 0.14 μm. The obtained adsorbent was classified into particles having a particle diameter of 300 μm to 500 μm using a sieve, and the degree of swelling was evaluated. In addition, a Pt adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

[Example 4]
70 parts by mass of a commercially available ethylene-vinyl alcohol copolymer (Kuraray Co., Ltd., E105) and 30 parts by mass of vinyl alcohol polymer (Kuraray Co., Ltd., PVA217) were heated at 210 ° C. using a lab plast mill. After melt-kneading for 3 minutes at a temperature, the compound obtained by cooling and solidifying the melt was pulverized, and particles having a particle size of 106 μm to 212 μm were classified using a sieve. Further, the obtained particles were stirred in hot water at 100 ° C. for 2 hours to extract only the vinyl alcohol polymer, thereby obtaining porous ethylene-vinyl alcohol copolymer particles. The average value of the major axis of the pores of the porous particles was 0.89 μm. The porous particles were irradiated with 60 kGy of γ rays, immersed in an isopropanol solution of glycidyl methacrylate substituted with nitrogen at 80 ° C., and stirred for 90 minutes to carry out graft polymerization. Thereafter, the obtained particles were washed with methanol and dried, and then the graft ratio was evaluated to be 323%. Further, the particles were immersed in an isopropanol solution of N- (2-aminoethyl) piperazine adjusted to 80 ° C. and reacted for 1 hour. After the reaction, the particles were washed with water and dried to obtain an adsorptive complex having an amino group. The amount of the functional group introduced into the adsorptive complex was 7.9 mmol / g, and the degree of swelling before the crosslinking treatment was 321%. The obtained adsorptive complex was immersed in an aqueous ethylene glycol diglycidyl ether solution adjusted to 40 ° C. and allowed to react for 1 hour. After the reaction, the particles were washed with water and dried to obtain the target adsorbent. The average value of the long diameter of the pores of the adsorbent was 0.71 μm. The obtained adsorbent was classified into particles having a particle diameter of 425 μm to 710 μm using a sieve, and the degree of swelling was evaluated. In addition, a Pt adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

[Example 5]
90 parts by mass of a commercially available ethylene-vinyl alcohol copolymer (Kuraray Co., Ltd., F101) and 10 parts by mass of a vinyl alcohol polymer (Kuraray Co., Ltd., PVA205) were heated at 210 ° C. using a lab plast mill. After melt-kneading for 3 minutes at a temperature, the compound obtained by cooling and solidifying the melt was pulverized, and particles having a particle size of 106 μm to 212 μm were classified using a sieve. Further, the obtained particles were stirred in hot water at 100 ° C. for 2 hours to extract only the vinyl alcohol polymer, thereby obtaining porous ethylene-vinyl alcohol copolymer particles. The average value of the major axis of the pores of the porous particles was 0.27 μm. The porous particles were irradiated with 100 kGy of γ rays, immersed in an isopropanol solution of glycidyl methacrylate substituted with nitrogen at 80 ° C., and stirred for 150 minutes for graft polymerization. Thereafter, the obtained particles were washed with methanol and dried, and then the graft ratio was evaluated and found to be 374%. Further, the particles were immersed in an isopropanol solution of diethylenetriamine adjusted to 80 ° C. and reacted for 1 hour. After the reaction, the particles were washed with water and dried to obtain an adsorptive complex having an amino group. The amount of functional groups introduced into the adsorptive complex was 8.7 mmol / g, and the degree of swelling before the crosslinking treatment was 389%. The obtained adsorptive complex was immersed in an aqueous ethylene glycol diglycidyl ether solution adjusted to 40 ° C. and allowed to react for 1 hour. After the reaction, the particles were washed with water and dried to obtain the target adsorbent. The average long diameter of the adsorbent pores was 0.20 μm. The obtained adsorbent was classified into particles having a particle diameter of 106 μm to 425 μm using a sieve, and the degree of swelling was evaluated. In addition, a Pt adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

[Example 6]
50 parts by mass of a commercially available ethylene-vinyl alcohol copolymer (Kuraray Co., Ltd., E105) and 50 parts by mass of vinyl alcohol polymer (Kuraray Co., Ltd., PVA205) were mixed at 210 ° C. with a lab plast mill. After melt-kneading for 3 minutes at a temperature, the compound obtained by cooling and solidifying the melt was pulverized, and particles having a particle diameter of 1180 μm to 1400 μm were prepared using a sieve. Further, the obtained particles were stirred in hot water at 100 ° C. for 2 hours to extract only the vinyl alcohol polymer, thereby obtaining porous ethylene-vinyl alcohol copolymer particles. The average pore diameter of the pores of the porous particles was 1.56 μm. The porous particles were irradiated with 60 kGy of γ rays, immersed in an isopropanol solution of glycidyl methacrylate substituted with nitrogen at 80 ° C., and stirred for 150 minutes for graft polymerization. Thereafter, the obtained particles were washed with methanol and dried, and then the graft ratio was evaluated and found to be 340%. Further, the particles were immersed in an isopropanol solution of diethylenetriamine adjusted to 80 ° C. and reacted for 4 hours. After the reaction, the particles were washed with water and dried to obtain an adsorptive complex having an amino group. The functional group introduction amount of the adsorptive complex was 6.9 mmol / g, and the degree of swelling before the crosslinking treatment was 356%. The obtained adsorptive complex was immersed in an aqueous ethylene glycol diglycidyl ether solution adjusted to 40 ° C. and allowed to react for 1 hour. After the reaction, the particles were washed with water and dried to obtain the target adsorbent. The average value of the major axis of the pores of the adsorbent was 1.42 μm. The obtained adsorbent was classified into particles having a particle diameter of 2100 μm to 2400 μm using a sieve, and the degree of swelling was evaluated. In addition, a Pt adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

[Example 7]
The adsorptive complex having iminodiacetic acid groups obtained in the same manner as in Example 1 was immersed in an aqueous solution of polyamide / epichlorohydrin resin (cross-linking agent “WS4020” manufactured by Seiko PMC Co., Ltd.) adjusted to 60 ° C., The reaction was carried out for 1 hour. After the reaction, the particles were washed with water and dried to obtain the target adsorbent. The average long diameter of the adsorbent pores was 0.20 μm. The obtained adsorbent was classified into particles having a particle diameter of 106 μm to 425 μm using a sieve, and the degree of swelling was evaluated. In addition, a Cu adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

[Example 8]
The adsorptive complex having an amino group obtained in the same manner as in Example 4 was immersed in an aqueous ethylene glycol diglycidyl ether solution adjusted to 40 ° C. and allowed to react for 1 hour. After the reaction, the particles were washed with water and dried to obtain the target adsorbent. The average value of the long diameters of the pores of the adsorbent was 0.69 μm. The obtained adsorbent was classified into particles having a particle diameter of 425 μm to 710 μm using a sieve, and the degree of swelling was evaluated. In addition, a Pt adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

[Comparative Example 1]
The target adsorbent was obtained in the same manner as in Example 1 except that the crosslinking treatment was not performed (functional group introduction amount: 5.04.6 mmol / g). The average long diameter of the adsorbent pores was 0.20 μm. The obtained adsorbent was classified into particles having a particle diameter of 106 μm to 425 μm using a sieve, and the degree of swelling was evaluated. In addition, a Cu adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

[Comparative Example 2]
The target adsorbent was obtained in the same manner as in Example 5 except that the crosslinking treatment was not performed (functional group introduction amount: 10.18.7 mmol / g). The average long diameter of the adsorbent pores was 0.19 μm. The obtained adsorbent was classified into particles having a particle diameter of 106 μm to 425 μm using a sieve, and the degree of swelling was evaluated. In addition, a Pt adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

[Comparative Example 3]
A commercially available ethylene-vinyl alcohol copolymer (E105, manufactured by Kuraray Co., Ltd.) was pulverized, and particles having a particle diameter of 425 μm to 710 μm were prepared using a sieve. The particles were irradiated with 10 kGy of γ rays, immersed in an isopropanol solution of glycidyl methacrylate substituted with nitrogen at 80 ° C., and stirred for 90 minutes for graft polymerization. Thereafter, the obtained particles were washed with methanol and dried, and the graft ratio was evaluated to be 11%. Further, the particles were immersed in an isopropanol solution of ethylenediamine adjusted to 80 ° C. and reacted for 1 hour. After the reaction, the particles were washed with water and dried to obtain the target adsorbent. The amount of functional group introduced into the adsorbent was 1.2 mmol / g. The obtained adsorbent was classified into particles having a particle diameter of 500 to 710 μm using a sieve, and the degree of swelling was evaluated. In addition, a Pt adsorption test was performed to evaluate metal adsorption performance. Table 1 shows the particle composition and performance evaluation results.

As shown in Examples 1 to 8, the adsorbent of the present invention exhibits good adsorptivity to metal ions. In particular, in Examples 1 to 5, since the swelling property is highly controlled while increasing the amount of the adsorptive functional group, particularly good adsorptivity to metal ions is shown. From the results of these examples, the adsorbent of the present invention is very effective when separating and recovering an adsorbed material such as metal ions.

As in Comparative Examples 1 and 2, the adsorbent that has not been subjected to the crosslinking treatment is swelled by water absorption, and the amount of adsorbent that can be filled is reduced, so that the adsorption performance per unit volume is significantly reduced. When the amount of the adsorbing functional group is reduced as in Comparative Example 3, it is easy to control the swelling, but the adsorption performance is remarkably lowered.

According to the present invention, it is possible to provide a new adsorbent that can be used industrially and has high adsorbability while highly controlling resin swelling due to water absorption. The adsorbent can efficiently recover various objects to be adsorbed, such as ions of platinum group metals, gold, silver, copper, nickel, chromium, vanadium, cobalt, lead, zinc, mercury, cadmium and the like.

As described above, the preferred embodiments of the present invention have been described. However, various additions, modifications, or deletions are possible without departing from the spirit of the present invention, and such modifications are also included in the scope of the present invention. It is.

Claims (12)

1. An ethylene-vinyl alcohol copolymer is used as a base material, and a polymer component P ₁ having a (meth) acrylic acid ester skeleton as a structural unit and having an adsorptive functional group as a graft chain is introduced into the base material. component P ₁ is crosslinked by a crosslinking component, adsorbent.
2. The adsorbent according to claim 1, wherein the degree of swelling represented by the following formula (I) is 50 to 200%.
   Swelling degree = {(mass after the adsorbent is shaken in hot water at 70 ° C. for 10 minutes to contain water) − (absolute dry mass of the adsorbed adsorbent)} / (absorption of the adsorbed adsorbent) (Dry mass) x 100 (%) (I)
3. The adsorbent according to claim 1 or 2, wherein the crosslinking component has any one or more functional groups selected from the group consisting of an amino group, an isocyanate group, an epoxy group, a carbodiimide group, and an azetidinium group.
4. The adsorbent according to any one of claims 1 to 3, wherein the adsorptive functional group is a glucamine group, a diol group, a polyol group, a group composed of a polyol and a nitrogen atom, an iminodiacetic acid group, an amino group, an ammonium group, An adsorbent that is at least one functional group selected from the group consisting of an amidoxime group, a dithiocarbamic acid group, a thiourea group, an isothiourea group, a phosphoric acid group, and a phosphonic acid group.
5. The adsorbent according to any one of claims 1 to 4, wherein the adsorbent is a porous body, and an average value of major diameters of pores formed on the surface of the porous body is within a range of 0.01 µm to 20 µm. Some adsorbent.
6. The adsorbent according to any one of claims 1 to 5, wherein the adsorbent is in the form of particles and the particle diameter ranges from 10 to 2000 µm.
7. The adsorbent according to any one of claims 1 to 6, which adsorbs metal ions.
8. A method for producing an adsorbent according to any one of claims 1 to 7,
   Preparing an ethylene-vinyl alcohol copolymer as a base component;
   A polymer component introduction step of introducing a polymer component P ₀ having a reactive (meth) acrylate skeleton as a structural unit into the base material component as a graft chain;
   An adsorption functional group introduction step of introducing an adsorption functional group to the polymer component P ₀ , having a (meth) acrylate skeleton as a structural unit, and obtaining a polymer component P ₁ having an adsorption functional group;
   A crosslinking step of crosslinking the polymer component P ₀ or P ₁ ;
   A method for producing an adsorbent comprising at least
9. The manufacturing method of claim 8, in the crosslinking step, the manufacturing method of adsorbent for performing crosslinking treatment on the polymer component P _1.
10. 10. The production method according to claim 8 or 9, wherein ionizing radiation is allowed to act on the substrate component to introduce a graft chain.
11. The manufacturing method of any one of claims 8-10, a manufacturing method is adsorptive functional group concentration in the complex of the polymeric component P ₁ and the substrate component is 1.5 mmol / g or more.
12. 11. The production method according to claim 8, wherein the graft ratio of the graft chain introduced in the polymer component introduction step is 30 to 900% by mass.