JP2016209836A - Adsorbent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adsorbent having excellent liquid passability and flowability when charged into a column, and a method for producing such an adsorbent.SOLUTION: The adsorbent is a particulate adsorbent composed of at least two polymer components, where the at least one of the polymer components is a vinyl alcoholic polymer, and an average roundness of the adsorbent is 0.80-1.00.SELECTED DRAWING: None

Description

  The present invention relates to an adsorbent excellent in liquid permeability and fluidity when packed in a column and a method for producing the same.

In recent years, the demand for metal resources such as precious metals and rare metals has been coupled with supply restrictions due to resource nationalism, leading to supply instability and rising prices, and the market is unstable.
Under such circumstances, the development of technologies and mechanisms for recycling used products, and the development of technologies to minimize losses as much as possible in the recovery and smelting processes are being carried out vigorously.

  Conventionally, for recovery of precious metals, removal of harmful metal ions, etc., there are known solvent extraction methods that extract metals using organic solvents such as dibutyl carbitol and adsorption methods that use chelating resins to separate and recover metals. In particular, the latter is suitable for dilute solution processing.

  In the case of a chelate resin, by using a polymer having a structure with high polarity as a base material, affinity with water can be improved and a metal can be effectively adsorbed. Patent Documents 1 and 2 disclose an adsorbent based on a highly hydrophilic vinyl alcohol polymer.

JP 2014-111732 A JP 2014-159547 A

  However, the adsorbents based on the vinyl alcohol polymers described in Patent Documents 1 and 2 have irregular shapes because they are granulated by pulverization. Therefore, when the adsorbent is packed in a column or the like, the adsorbent is likely to become dense and dense in the column, and there is a risk that the liquid will be poor in long-term operation. In addition, when liquid flow is performed by upflow or when regular backwashing is performed by downflow, the shape of the adsorbent is poor and the resin layer rises in accordance with the upward flow. There was also a problem that required column design.

  The present invention has been made in order to solve the above-mentioned problems, and is an adsorbent based on a vinyl alcohol polymer having high hydrophilicity and excellent adsorption characteristics, and an adsorbent having a shape control close to a spherical shape. And to provide a method for producing such an adsorbent.

  The inventors of the present invention have intensively studied to achieve the above object, and as a result, found that the fluidity of the adsorbent in the column can be greatly improved by applying shape control close to a spherical shape as expected, and the present invention. It came to.

  That is, the first embodiment of the present invention is a particulate adsorbent composed of at least two types of polymer components, and at least one of the polymer components is a vinyl alcohol polymer, The adsorbent has an average area circularity of 0.80 to 1.00.

For example, the adsorbent may have a minimum area circularity of 0.55 or more, and a swelling degree represented by the following formula (I) may be 50 to 300%.
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)} / (absolute amount of adsorbed adsorbent) (Dry mass) x 100 (%) (I)

  The adsorbent may have a water-containing average particle size of about 20 to 2000 μm.

  In the adsorbent, the vinyl alcohol polymer is preferably an ethylene-vinyl alcohol copolymer.

  Since the adsorbent of the present invention has a shape control close to a sphere while using a highly hydrophilic skeleton as a base material, the adsorbent has excellent adsorption performance, excellent fluidity in the column, and is compact. Column design is possible.

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

  The first embodiment of the present invention is a particulate adsorbent composed of at least two types of polymer components, and at least one of the polymer components is a vinyl alcohol polymer, and the area of the adsorbent is circular. It is an adsorbent having an average value of 0.80 to 1.00.

[Area circularity]
The adsorbent of the present invention is excellent in fluidity at the time of upflow because the particle shape is controlled to have an average value of the area circularity of 0.80 to 1.00. More preferably, it is 0.82-1.00, More preferably, it is 0.84-1.00. When the average value of the area circularity is less than 0.80, the fluidity is remarkably deteriorated. The numerical value is 1.00, that is, the fluidity improves as it approaches a perfect circle. The area circularity is a numerical value represented by the following formula (II), and can be calculated, for example, by image analysis described in the examples.
Area circularity = 4 × π × area / (peripheral length) ² (II)

  In addition, the minimum value of the area circularity of the adsorbent of the present invention is preferably 0.55 or more, more preferably 0.58 or more, and preferably 0.60 or more from the viewpoint of fluidity. Further preferred. When the minimum value of the area circularity is less than 0.55, the fluidity may be deteriorated.

[Components of adsorbent]
Although the form of the at least 2 or more types of polymer component contained in the adsorbent of this invention is not specifically limited, The state in which polymer components were mixed and the state in which polymer components have a chemical bond are mentioned. A method for forming such a composite state of polymer components is not particularly limited. For example, (1) a method in which a polymer component is mixed in a solution or mixed in a molten state, and (2) another polymer using a specific polymer component as a backbone polymer. Examples include a method of modifying or graft polymerizing components, and (3) a method of crosslinking polymer components combined by the methods (1) and (2) with a crosslinking agent. The important point in the present invention is that a means for processing the polymer into spherical particles in the range of the above-mentioned area circularity in the process of forming the composite state of the polymer components or in any stage of preparing the trunk polymer of (2). It is to apply.

  In particular, when the method (2) is used, the target polymer is maintained while maintaining the spherical shape by using a trunk polymer that has been processed into spherical particles in the range of the above-mentioned area circularity and modifying or graft polymerizing by a solid-liquid reaction. Can be obtained.

[Particle shape control method]
The spherical particle processing means is not particularly limited as long as it can be processed into a shape satisfying the above-mentioned area circularity range, for example, a method such as dissolution / precipitation method, spray drying, surface modification by heat treatment, underwater cut, etc. Is mentioned. Among these, since the structure control of the vinyl alcohol polymer is easy, a dissolution / precipitation method and an underwater cut are particularly preferably used.

[Polymer component]
One or more polymer components contained in the adsorbent of the present invention are vinyl alcohol polymers, so that they have high hydrophilicity and excellent adsorption characteristics. Vinyl alcohol polymers include, for example, vinyl acetate derivative polymers such as polyvinyl alcohol, ethylene-vinyl alcohol copolymers, polyvinyl acetals (for example, polyvinyl alcohol acetals formed by various aldehydes such as formaldehyde, acetaldehyde, butyraldehyde). Is mentioned. Among these, an ethylene-vinyl alcohol copolymer having an excellent balance between water resistance and hydrophilicity is preferably used.

  The ethylene-vinyl alcohol copolymer is not particularly limited as long as it exhibits the desired adsorption performance. For example, the ethylene content may be about 10 to 60 mol%, or about 20 to 50 mol%. preferable. When ethylene content is less than 10 mol%, there exists a possibility that the water resistance of an adsorbent may fall. On the other hand, when the ethylene content exceeds 60 mol%, it is difficult to produce and difficult to obtain.

  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 less than 90 mol%, the moldability may be deteriorated or the water resistance of the resulting adsorbent may be lowered.

  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 / min or more, and more preferably 0.5 g / min or more. If it is less than 0.1 g / min, 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, 25 g / min or less may be sufficient.

The ethylene-vinyl alcohol copolymer of the present invention may contain another unsaturated monomer unit 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 polymer component other than the vinyl alcohol polymer is not particularly limited, and a polymer having a functional group suitable for an adsorption target can be selected. For example, polyvinyl alkyl alcohol, polyalkylene glycol, polyvinyl alkyl ether, polyalkylene oxide, poly (meth) acrylamide, polyacrylonitrile, polyvinyl pyrrolidone, cationic polymer (for example, polyethyleneimine, polyallylamine, polyvinylamine, polyamidoamine dendrimer, polypyridine , Polyvinylpyridine, polyamino acid, polydiallyldimethylammonium halide, polyvinylbenzyltrimethylammonium halide, polydiacryldimethylammonium halide, polydimethylaminoethyl methacrylate hydrochloride, polynucleotide, etc.), anionic polymer (eg, polystyrene sulfonic acid, polyvinyl sulfate) , Poly (meth) acrylic acid, polymaleic acid, poly Amic acid), phenol resin, polyamide, polyvinyl pyrrolidone, cellulose derivative, dextrin, chitin, chitosan, graft polymer composed of various trunk polymers [for example, the above-mentioned vinyl alcohol polymer, amide resin (for example, nylon) 6; Nylon 6,6; Nylon 6,10; Nylon 6,12; Nylon 11; Nylon 12; Nylon 4,6), cellulosic resins (for example, cellulose (pulp, cotton linter, regenerated cellulose, etc.), cellulose triacetate, Cellulose acylates such as cellulose diacetate, cellulose acetate butyrate and cellulose acetate propionate), (meth) acrylic acid ester resins (for example, poly (meth) methyl acrylate, poly (meth) acrylic) Ethyl, poly (meth) acrylic acid propyl, (meth) acrylic acid ester and various copolymers such as (meth) acrylic acid and styrene), chitosan tree (for example, (1 → 4) -2-acetamido-2 -Partially fully deacetylated structure of chitin having deoxy-β-D-glucan structure, and part of deacetylated amino group of the structure, or part of hydroxyl group in the same molecule is acylated Reaction, etherification reaction, esterification reaction, chitosan derivatives chemically modified by other reactions, etc.)].

  As a method for obtaining a graft polymer composed of various trunk polymers, various known methods can be used. For example, a method of introducing a graft chain using radical polymerization using a polymerization initiator, using ionizing radiation Examples thereof include a method of generating a radical and introducing a graft chain. Among these, from the viewpoint of high graft chain introduction efficiency, a method of introducing a graft chain using ionizing radiation is preferably used.

  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 the unsaturated monomer to the above-mentioned trunk polymer using ionizing radiation, a mixed irradiation method of irradiating radiation in the presence of the trunk polymer and the unsaturated monomer, or only the trunk polymer in advance. After irradiation, any of the pre-irradiation methods where the unsaturated monomer and the trunk polymer are brought into contact with each other is possible, but the latter method is characterized in that it does not easily generate side reactions other than graft polymerization. Have.

  In the graft polymerization, as a method of bringing the trunk polymer and the unsaturated monomer into contact with each other, a liquid phase polymerization method in which a liquid unsaturated monomer or an unsaturated monomer solution is brought into direct contact with the unsaturated monomer, There is a gas phase graft polymerization method in which the body is contacted in a vapor or vaporized state, but it can be selected according to the purpose.

  Although it does not specifically limit as a dose irradiated with ionizing radiation, 5-230 kGy is preferable, 10-190 kGy is more preferable, 15-140 kGy is further more preferable. 20-100 kGy is most preferred. If the dose is less than 5 kGy, the dose is too small and the graft rate may decrease, and the desired adsorption performance may not be obtained. When it exceeds 230 kGy, there are concerns that the treatment process is costly and the trunk polymer is deteriorated during irradiation.

  When introducing a graft chain having an adsorptive functional group, an unsaturated monomer having an adsorptive functional group may be grafted, or an unsaturated monomer having a reactive group may be grafted using ionizing radiation. It may be converted into an adsorptive functional group after the formation.

[Swelling degree]
The adsorbent of the present invention has a degree of swelling represented by the following formula (I) of, for example, 50 to 300% from the viewpoint of preventing column blockage and fluidity deterioration due to water absorption swelling while maintaining affinity with water. There may be.
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)} / (absolute amount of adsorbed adsorbent) (Dry mass) x 100 (%) (I)
Preferably, the degree of swelling is 250% or less, more preferably 200% 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 why the adsorbent is swollen 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.

[Crosslinking method]
A method for controlling the degree of swelling to the above-mentioned range is not particularly limited, but a method of cross-linking polymer components with a cross-linking agent like the above-described method (3) is preferably used. 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.

  The reaction temperature can be appropriately set according to the type of the crosslinking agent. For example, the reaction rate can be improved, the swelling property of the polymer after the addition reaction can be within an appropriate range, and the spherical shape of the particles For example, the temperature for performing the crosslinking treatment may be, for example, about 20 to 100 ° C, preferably about 30 to 90 ° C.

  Various crosslinking agents can be used as long as they have crosslinkability, such as ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, Diamine compounds such as isophoronediamine, 1,3-bisaminomethylcyclohexane, diaminodiphenylmethane, m-phenylenediamine, diaminodiphenylsulfone, dicyandiamide; diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, Polyamine compounds such as polyvinylamine, polyallylamine, polyethyleneimine, polyamidoamine, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide Hydrazine compounds such as adipic acid dihydrazide, 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin, polyacrylic acid hydrazide, hydrazine carbonate, “Duranate” (WB40-100, WB40-80D, manufactured by Asahi Kasei Chemicals Corporation) WE50-100, WT30-100, WT20-100, etc.); tolylene diisocyanate (TDI); hydrogenated TDI; trimethylolpropane-TDI adduct (for example, “DesmodurL” manufactured by Bayer); triphenylmethane triisocyanate; Hydrogenated MDI; Polymerized MDI; Hexamethylene diisocyanate; Xylylene diisocyanate; 4,4-Dicyclohexylmethane diisocyanate; Isophorone dii Cyanate and its aqueous dispersion, “Denacol” manufactured by Nagase ChemteX Corporation (EX-611, EX-612, EX-614, EX-614B, EX-622, EX-512, EX-521, EX-411, 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, tet Hydroxyphenylmethane 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, novolac glycidyl ether Glycidyl ether type such as 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; phthalic acid diglycidyl ester , Tetrahydrophthalic acid diglycidyl ester, hexahydrophthalate Glycidyl ester types such as 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, epoxidized Linear aliphatic epoxy resins such as 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 Aliphatic epoxy resins such as (2,3-epoxycyclopentyl) ether and limonene dioxide, “Carbodilite” (SV-02, V-02, V-02-L2, V-04, E-made by Nisshinbo Chemical Co., Ltd.) 01, E-02), manufactured by Seiko PMC Co., Ltd. (WS4002, WS4020, WS4024, WS4030, WS4046, WS4010, CP8970), and the like.

[Particle size]
Although the average particle diameter in the water-containing state of the adsorbent of the present invention is not particularly limited, for example, 20 μm to 2000 μm is preferable, 30 μm to 1800 μm is more preferable, and 40 μm to 1500 μm is most preferable. When the particle diameter is less than 20 μm, the fluidity tends to deteriorate even if the area circularity of the particles is controlled within the above range. When the particle diameter exceeds 2000 μm, sufficient adsorption performance may not be obtained. In addition, the average particle diameter in a hydrous state shows the value measured in the state which adsorbent disperse | distributed to water like the method described in the Example mentioned 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 the 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. Recovery, removal of hazardous metals (such as mercury, cadmium, etc.) contained in factory wastewater, mine wastewater, hot spring water, etc., or general river water, lake water, seawater, soil elution water, water for use, biological treatment water, etc. From treated water after pre-treatment (for example, sand filtration treatment, rough filtration treatment using water treatment membrane, coagulation sedimentation treatment, ozone treatment, adsorption treatment using existing adsorbent or activated carbon, biological treatment) It can be used for removal of substances that cause membrane fouling (for example, dissolved organic components such as biopolymers and humic substances).

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited at all by these Examples.

[Water-containing average particle diameter]
The diameter of the adsorbent particles during water dispersion was measured using a laser diffraction / scattering particle size distribution analyzer “LA-920” manufactured by HORIBA, Ltd.

[Swelling degree]
Adsorbent particles (corresponding to 0.3 g as a dry pure content) were 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

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

[Area circularity measurement]
Using a particle image analyzer “Morphology G3S” manufactured by Malvern, the adsorbent particles in a water-containing state were subjected to image analysis, and the area circularity (minimum value, maximum value, average value) was measured. The average value is a value calculated by (total of area circularity of each particle) / (number of particles in image analysis (parameter)). The number of parameters was 50 or more.

[Fluidity evaluation]
An adsorbent was packed in a chromatographic column having a diameter of 30 mm so that the layer height was 60 mm (L / D = 2). Deionized water was passed through the column by upflow using a diaphragm pump. The flow state of the resin was visually evaluated while varying the linear velocity of liquid flow. In addition, the point in time when the state in which all of the filled resin was completely convected and mixed was recognized as “completely flowing”. Also, measure the distance (A [mm]) from the bottom of the column tower to the highest point of the resin fluidized bed at the time of “complete flow”, and calculate the packed bed height elevation (column radius magnification) according to the following formula did.
Increase in packed bed height = (A-60) / 15

[Example 1]
A commercially available ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., C109) was dissolved in dimethyl sulfoxide to prepare a polymer solution having a concentration of 16% by mass. This solution was heated to 80 ° C., and discharged from a nozzle having an opening diameter of 300 μm at a pressure of 600 mbar and dropped into a water bath (room temperature) stirred with a stirrer to prepare ethylene-vinyl alcohol copolymer particles. The particles were stirred and washed with water three times, then dried with hot air at 100 ° C. for 3 hours, and the resulting dried particles were irradiated with 150 kGy of γ rays. Next, the γ-irradiated particles were immersed in a methanol solution of glycidyl methacrylate substituted with nitrogen at 60 ° C. and stirred for 150 minutes to carry out graft polymerization. The obtained particles were washed with methanol and dried, and the graft ratio was evaluated to be 383%. The particles were added to d-DMSO and stirred at 70 ° C. for 1 hour, and then the extract was analyzed by ¹ H-NMR. As a result, it was found that an unreacted ethylene-vinyl alcohol copolymer remained. confirmed. Further, the particles were immersed in a methanol solution of diethylenetriamine adjusted to 60 ° C. and reacted for 2 hours. After the reaction, the particles were washed with water and vacuum dried at 40 ° C. for 12 hours to obtain an adsorbent having an amino group. The adsorbent 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 centrifuged at 3000 rpm for 5 minutes to obtain the target adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Example 2]
A commercially available ethylene-vinyl alcohol copolymer (F101, manufactured by Kuraray Co., Ltd.) was dissolved in dimethyl sulfoxide to prepare a polymer solution having a concentration of 16% by mass. This solution was heated to 80 ° C., and discharged from a nozzle having an opening diameter of 300 μm at a pressure of 600 mbar and dropped into a water bath (room temperature) stirred with a stirrer to prepare ethylene-vinyl alcohol copolymer particles. The particles were stirred and washed with water three times, then dried with hot air at 100 ° C. for 3 hours, and the resulting dried particles were irradiated with 150 kGy of γ rays. Next, the γ-irradiated particles were immersed in a methanol solution of glycidyl methacrylate substituted with nitrogen at 60 ° C. and stirred for 150 minutes to carry out graft polymerization. The obtained particles were washed with methanol and dried, and the graft ratio was evaluated to be 350%. The particles were added to d-DMSO and stirred at 70 ° C. for 1 hour, and then the extract was analyzed by ¹ H-NMR. As a result, it was found that an unreacted ethylene-vinyl alcohol copolymer remained. confirmed. Further, the particles were immersed in an isopropanol solution of ethylenediamine adjusted to 80 ° C. and reacted for 2 hours. After the reaction, the particles were washed with water and vacuum dried at 40 ° C. for 12 hours to obtain an adsorbent having an amino group. The adsorbent 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 centrifuged at 3000 rpm for 5 minutes to obtain the target adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Example 3]
A commercially available ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., G130) was dissolved in dimethyl sulfoxide to prepare a polymer solution having a concentration of 18% by mass. This solution was heated to 80 ° C., and discharged from a nozzle having an opening diameter of 300 μm at a pressure of 450 mbar, and dropped into a water bath (room temperature) stirred with a stirrer to prepare ethylene-vinyl alcohol copolymer particles. The particles were stirred and washed with water three times, then dried with hot air at 100 ° C. for 3 hours, and the resulting dried particles were irradiated with 150 kGy of γ rays. Next, the γ-irradiated particles were immersed in a methanol solution of glycidyl methacrylate substituted with nitrogen at 60 ° C. and stirred for 150 minutes to carry out graft polymerization. The obtained particles were washed with methanol and dried, and the graft ratio was evaluated and found to be 251%. The particles were added to d-DMSO and stirred at 70 ° C. for 1 hour, and then the extract was analyzed by ¹ H-NMR. As a result, it was found that an unreacted ethylene-vinyl alcohol copolymer remained. confirmed. Further, the particles were immersed in a methanol solution of diethylenetriamine adjusted to 60 ° C. and reacted for 2 hours. After the reaction, the particles were washed with water and vacuum dried at 40 ° C. for 12 hours to obtain an adsorbent having an amino group. The adsorbent 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 centrifuged at 3000 rpm for 5 minutes to obtain the target adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Example 4]
A commercially available ethylene-vinyl alcohol copolymer (Kuraray Co., Ltd., G130) is melted with a biaxial kneader (resin temperature 218 ° C.) and discharged from a die having a hole diameter of 360 μm (die temperature 315 ° C.), underwater pelletizer To obtain ethylene-vinyl alcohol copolymer particles (granulation rate: 560 kg / hour). The particles were dried with hot air at 100 ° C. for 3 hours, and the resulting dried particles were irradiated with 150 kGy of γ rays. Next, the γ-irradiated particles were immersed in a methanol solution of glycidyl methacrylate substituted with nitrogen at 60 ° C. and stirred for 150 minutes to carry out graft polymerization. The obtained particles were washed with methanol and dried, and the graft ratio was evaluated to be 119%. The particles were added to d-DMSO and stirred at 70 ° C. for 1 hour, and then the extract was analyzed by ¹ H-NMR. As a result, it was found that an unreacted ethylene-vinyl alcohol copolymer remained. confirmed. Further, the particles were immersed in a methanol solution of diethylenetriamine adjusted to 60 ° C. and reacted for 2 hours. After the reaction, the particles were washed with water and vacuum dried at 40 ° C. for 12 hours to obtain an adsorbent having an amino group. The adsorbent 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 centrifuged at 3000 rpm for 5 minutes to obtain the target adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Example 5]
The graft polymer particles of Example 4 (graft rate 119%) were immersed in an iminodiacetic acid aqueous solution adjusted to 80 ° C. and reacted for 2 hours. After the reaction, the particles were washed with water and vacuum dried at 40 ° C. for 12 hours to obtain an adsorbent having a carboxyl group. The adsorbent was immersed in an aqueous calcium chloride solution at room temperature and allowed to react for 1 hour. After the reaction, the particles were washed with water and centrifuged at 3000 rpm for 5 minutes to obtain the target adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Example 6]
A commercially available ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., G130) was dissolved in dimethyl sulfoxide to prepare a polymer solution having a concentration of 18% by mass. This solution was heated to 80 ° C., and discharged from a nozzle having an opening diameter of 300 μm at a pressure of 450 mbar, and dropped into a water bath (room temperature) stirred with a stirrer to prepare ethylene-vinyl alcohol copolymer particles. The particles were stirred and washed with water three times, then dried with hot air at 100 ° C. for 3 hours, and the resulting dried particles were irradiated with 30 kGy γ rays. Next, the γ-irradiated particles were immersed in a methanol solution of glycidyl methacrylate substituted with nitrogen at 60 ° C. and stirred for 150 minutes to carry out graft polymerization. The obtained particles were washed with methanol and dried, and the graft ratio was evaluated to be 71%. The particles were added to d-DMSO and stirred at 70 ° C. for 1 hour, and then the extract was analyzed by ¹ H-NMR. As a result, it was found that an unreacted ethylene-vinyl alcohol copolymer remained. confirmed. Furthermore, this particle | grain was immersed in the methanol solution of ethylenediamine adjusted to 60 degreeC, and was made to react for 2 hours. After the reaction, the particles were washed with water and vacuum dried at 40 ° C. for 12 hours to obtain an adsorbent having an amino group. The particles were washed with water and centrifuged at 3000 rpm for 5 minutes to obtain the intended adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Example 7]
A commercially available ethylene-vinyl alcohol copolymer (C109, manufactured by Kuraray Co., Ltd.) is melted with a twin-screw kneader (resin temperature 222 ° C.) and discharged from a die having a hole diameter of 500 μm (die temperature 315 ° C.), underwater pelletizer To obtain ethylene-vinyl alcohol copolymer particles (granulation rate: 55 kg / hour). The particles were dried with hot air at 100 ° C. for 3 hours, and the resulting dried particles were irradiated with 150 kGy of γ rays. Next, the γ-irradiated particles were immersed in a methanol solution of glycidyl methacrylate substituted with nitrogen at 60 ° C. and stirred for 150 minutes to carry out graft polymerization. The obtained particles were washed with methanol and dried, and the graft rate was evaluated to be 301%. The particles were added to d-DMSO and stirred at 70 ° C. for 1 hour, and then the extract was analyzed by ¹ H-NMR. As a result, it was found that an unreacted ethylene-vinyl alcohol copolymer remained. confirmed. Further, the particles were immersed in a methanol solution of diethylenetriamine adjusted to 60 ° C. and reacted for 2 hours. After the reaction, the particles were washed with water and vacuum dried at 40 ° C. for 12 hours to obtain an adsorbent having an amino group. The adsorbent 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 centrifuged at 3000 rpm for 5 minutes to obtain the target adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Example 8]
75 parts by mass of a commercially available ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., C109) and 25 parts by mass of polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., SP-200) were melted with a biaxial kneader (resin temperature 217). C.) and discharged from a die having a hole diameter of 500 .mu.m (die temperature 315.degree. C.) and granulated with an underwater pelletizer (granulation rate 55 kg / hour) to prepare ethylene-vinyl alcohol copolymer / polyethyleneimine composite particles. The particles were dried with hot air at 100 ° C. for 3 hours, then immersed in an aqueous solution of ethylene glycol diglycidyl ether at room temperature and allowed to react for 1 hour. After the reaction, the particles were washed with water and centrifuged at 3000 rpm for 5 minutes to obtain the target adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Example 9]
70 parts by mass of a commercially available ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., G130) and 30 parts by mass of polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., SP-200) were melted with a biaxial kneader (resin temperature 215). C.) and discharged from a die having an opening diameter of 500 .mu.m (die temperature 315.degree. C.) and granulated with an underwater pelletizer (granulation rate 60 kg / hr) to prepare ethylene-vinyl alcohol copolymer / polyethyleneimine composite particles. The particles were dried with hot air at 100 ° C. for 3 hours, then immersed in an aqueous solution of ethylene glycol diglycidyl ether at room temperature and allowed to react for 1 hour. After the reaction, the particles were washed with water and centrifuged at 3000 rpm for 5 minutes to obtain the target adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Example 10]
In the adsorbent of Example 1, the crosslinking treatment with ethylene glycol diglycidyl ether was not performed. Table 1 shows the physical property evaluation results and fluidity evaluation results of the adsorbent.

[Comparative Example 1]
A commercially available ethylene-vinyl alcohol copolymer (F101, manufactured by Kuraray Co., Ltd.) was pulverized, and particles having a particle diameter of 150 μm to 300 μm were prepared using a sieve. The particles were irradiated with 150 kGy of gamma rays. Next, the γ-irradiated particles were immersed in a methanol solution of glycidyl methacrylate substituted with nitrogen at 60 ° C. and stirred for 150 minutes to carry out graft polymerization. The obtained particles were washed with methanol and dried, and then the graft ratio was evaluated and found to be 378%. The particles were added to d-DMSO and stirred at 70 ° C. for 1 hour, and then the extract was analyzed by ¹ H-NMR. As a result, it was found that an unreacted ethylene-vinyl alcohol copolymer remained. confirmed. Further, the particles were immersed in a methanol solution of diethylenetriamine adjusted to 60 ° C. and reacted for 2 hours. After the reaction, the particles were washed with water and vacuum dried at 40 ° C. for 12 hours to obtain an adsorbent having an amino group. The adsorbent 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 centrifuged at 3000 rpm for 5 minutes to obtain the target adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Comparative Example 2]
75 parts by mass of a commercially available ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., C109) and 25 parts by mass of polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., SP-200) were melt-kneaded at 210 ° C with a lab plast mill. After pulverization, ethylene-vinyl alcohol copolymer / polyethyleneimine composite particles having a particle diameter of 425 μm to 710 μm were prepared using a sieve. The particles were immersed in a room temperature aqueous ethylene glycol diglycidyl ether solution and allowed to react for 1 hour. After the reaction, the particles were washed with water and centrifuged at 3000 rpm for 5 minutes to obtain the target adsorbent. Table 1 shows the physical property evaluation results and fluidity evaluation results of the obtained adsorbent.

[Reference Example 1]
Metal ion adsorption performance was evaluated using the adsorbent of Example 1. 50 mg of adsorbent (as dry weight) was added to 200 mL of 0.1N hydrochloric acid solution having a metal ion concentration of 100 mg / L, and stirred at 25 ° C. for 60 minutes. Thereafter, 1 mL of the solution was sampled and made up to 50 mL, and then the metal concentration measured with an ICP emission spectrometer (manufactured by Niger Jarrel Ash, IRIS-AP) was defined as C1 (mg / L). The metal adsorption rate was determined from the following equation. The results are shown in Table 2.
Metal adsorption rate (%) = (100−C1) × 100
[Reference Example 2]
Using the adsorbent of Example 5, the metal ion adsorption performance was evaluated. 50 mg of adsorbent (as dry weight) was added to 150 mL of 0.001 N sulfuric acid solution having a metal ion concentration of 30 mg / L and stirred at 23 ° C. for 60 minutes. Thereafter, 1 mL of the solution was sampled and made up to 50 mL, and then the metal concentration measured with an ICP emission analyzer (manufactured by Nippon Jarrell Ash, IRIS-AP) was defined as C2 (mg / L). The metal adsorption rate was determined from the following equation. The results are shown in Table 2.
Metal adsorption rate (%) = (30−C2) × 100
[Reference Example 3]
Biopolymer adsorption performance was evaluated using the adsorbent of Example 8. Add 1.0 g of adsorbent (as dry weight) to 200 mL aqueous solution of sodium alginate with concentration of 4.3 mg-C / L (manufactured by Wako Pure Chemical Industries, Ltd., model number: 199-09961, model material of biopolymer). And stirred at 25 ° C. for 18 hours. Thereafter, 40 ml of the supernatant was sampled and evaluated by measuring the sodium alginate concentration (mg-C / L) using a total organic carbon analyzer “TOC-300V” manufactured by Mitsubishi Chemical Analytech. The adsorption rate of the biopolymer by the adsorbent was evaluated as follows. The results are shown in Table 2.
Biopolymer adsorption rate = (sodium alginate concentration before adsorption evaluation−sodium alginate concentration after adsorption evaluation) / sodium alginate concentration before adsorption evaluation × 100 (%)

  As shown in Examples 1 to 10, the adsorbent of the present invention is excellent in fluidity at the time of column packing because the shape of the adsorbent is controlled in a shape close to a sphere.

  As in Comparative Examples 1 and 2, in the adsorbent that has not been shape-controlled, the density of the resin occurs in the column, not only the liquid flow speed required until the whole is completely mixed, The rise in packed bed height until convection is also large.

  ADVANTAGE OF THE INVENTION According to this invention, the novel adsorbent which can be used industrially which has the high fluidity | liquidity at the time of column packing, and has the outstanding adsorption | suction performance can be provided. Since the fluidity is high, for example, when the column tower is backwashed, the rise in the resin layer height is small, so that the column design can be made compact. In addition, the adsorbent, for example, collects metal ions such as platinum group metals, gold, silver, copper, nickel, chromium, vanadium, cobalt, or dissolved organic components (for example, biopolymers) contained in river water. Can be efficiently removed.

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 (5)

  It is a particulate adsorbent composed of at least two kinds of polymer components, and at least one of the polymer components is a vinyl alcohol polymer, and the average value of the area circularity of the adsorbent is 0.80 to 1. Adsorbent that is 0.00.   The adsorbent according to claim 1, wherein the minimum value of the area circularity is 0.55 or more. The adsorbent according to claim 1 or 2, wherein the degree of swelling represented by the following formula (I) is 50 to 300%.
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)} / (absolute amount of adsorbed adsorbent) (Dry mass) x 100 (%) (I)   The adsorbent according to any one of claims 1 to 3, wherein the water-containing average particle diameter is 20 to 2000 µm.   The adsorbent according to any one of claims 1 to 4, wherein the vinyl alcohol polymer is an ethylene-vinyl alcohol copolymer.