JP6156832B2 - Method for producing radioactive material collection material - Google Patents

Description

  The present invention relates to a radionuclide trapping material. The present invention relates to a material for removing radioactive nuclides from waste liquids and waste gases containing radioactive substances generated from nuclear facilities such as nuclear power plants and radioisotope handling establishments, and a manufacturing method thereof. In particular, the present invention relates to a material that can efficiently separate and remove radioactive substances from waste liquids and waste gases containing radioactive substances generated in the event of a nuclear facility, and to minimize the exposure of workers, and a method for manufacturing the same. It is.

Conventionally, a coagulation sedimentation method, an ion exchange method, or a combination of these methods is used to separate and remove radionuclides in a radioactive liquid waste.
For example, as described in Patent Document 1, the coagulation sedimentation method is a method in which a coagulant is added to a waste liquid, mixed and stirred to form an aggregation floc, and then subjected to sedimentation separation. Radionuclides are taken into the floc during the floc formation process. As the flocculant, sulfate band, polyaluminum chloride (PAC), iron salt or the like is used. Here, when the polymer flocculant is used in combination, the polymer chain entangles the fine flocs, so that flocs having a large floc diameter and a large sedimentation speed are formed. Since it is an inexpensive and simple method, it is suitable for treating a large amount of dilute waste liquid. However, when a large amount of a flocculant is injected for the purpose of increasing the decontamination factor, there is a problem that a large amount of agglomerated sedimentation sludge is generated. Moreover, since relatively large facilities such as a coagulation tank, a sedimentation tank, and a chemical injection facility are required, it was difficult to respond to an accident at a nuclear facility.

  An ion exchange method using a bead-shaped ion exchange resin used for general water treatment has also been proposed. In the ion exchange method, since the shape of the ion exchange resin to be used is a spherical shape of about 0.5 mm, it is generally used by filling a column. This method is often performed after coagulation sedimentation or filtration, and the entire plant equipment including the apparatus for performing the ion exchange method can be relatively large. In the case of a serious accident, there is a possibility that each component of the plant facility may be damaged or the supply of electric power may be interrupted, and the ion exchange device may not function normally.

  Patent Document 2 proposes that a particulate inorganic ion exchanger such as zeolite can be used in the ion exchange method. Inorganic ion exchangers are difficult to handle because of their high specific gravity and poor fluidity. In addition, when the column is filled with an inorganic ion exchanger, there is a problem that may occur when the above-described ion exchange resin is used. In addition, there is a method of packing the inorganic ion exchanger into a bag and stacking it as a sandbag at the place where the radioactive material is discharged, but since the sandbag of the inorganic ion exchanger is heavy, it is necessary to install heavy machinery to install it. The operation by is necessary.

  On the other hand, it has been known since the 1960s that metal ferrocyanate adsorbs cesium well. For example, Non-Patent Document 1 discloses a description of a cesium adsorbent in which a ferrocyanic acid metal salt is supported on an anion exchange resin. However, since the ferrocyanate metal salt is in the form of particles, there are problems such as poor operability during use and low cesium adsorption rate, especially in facilities handling radioactive isotopes such as nuclear power plants. It cannot be said that it can function effectively against disasters.

There exists patent document 3 as an example which carry | supported the ferrocyanic acid metal salt to the fiber. Patent Document 3 discloses that high collection performance for radionuclides such as cesium was obtained by supporting a ferrocyanate metal salt compound on an acrylic fiber. According to Patent Document 3, the acrylic fiber is dipped in a potassium ferrocyanate solution and dried, and then dipped in an aqueous nitrate solution of cobalt, nickel, etc. and then dried several times, and K2M ^II [ Fe (CN) 6] (M ^II is a divalent metal) is supported and immobilized on a ferrocyanate metal salt with a chemical structure.

  However, the ferrocyanate metal salt-supported fiber by this production method has a small interaction between the base fiber and the ferrocyanate metal salt, and the ferrocyanate metal salt is supported only on the surface of the fiber, The ferrocyanic acid metal salt may peel off depending on the environment such as the composition and temperature of the liquid used. In order to increase the amount of ferrocyanic acid metal salt supported on the fiber, it is necessary to repeat the steps of immersing and drying the two kinds of liquids many times, and the operation is complicated. And this ferrocyanic acid metal salt carrying | support fiber can collect various radionuclides, However, The collection rate of strontium is very low.

JP 61-239196 JP2000-84418 Shoko 63-24415 Journal of Nuclear Science & Technology, 6 [6], p309-312 (June 1968)

  In view of such prior art, the present invention is a relatively lightweight and easy-to-handle radioactive material trap that can cope with a large-scale disaster at a radioactive isotope handling facility where many kinds of radioactive materials can be discharged. The purpose is to provide materials. Furthermore, the present invention provides a method for producing and using a radioactive material collecting material, and a protective article from radiation using the radioactive material collecting material.

Aspects of the present invention are as follows:
1. Radioactive substance trapping, characterized in that a ferrocyanate metal salt is held between graft chains of an organic polymer molded article into which graft chains having ion exchange groups and / or chelate groups have been introduced by radiation graft polymerization. Collecting material.
2. In the above 1, the metal of the ferrocyanate metal salt is selected from the group consisting of Co, Zn, Zr, Ni, Ti, Al, Fe, Mn, and Cu and / or an alkali metal of Li, Na, K The radioactive material collection material of description.
3. The ion exchange group is selected from the group consisting of a sulfonic acid group, a carboxyl group, a phosphoric acid group, a quaternary ammonium group, an amino group, and the chelating group contains one or more iminodiacetic acid groups and primary to tertiary amino groups The radioactive material collection material of said 1 or 2 selected from the group which consists of an amino-type functional group, amidoxime group, and a hydroxamic acid group.
4). The radioactive substance according to any one of 1 to 3 above, wherein the organic polymer molded body is selected from the group consisting of fibers, nonwoven fabrics, woven fabrics, twisted yarns, membranes, porous membranes, powders or processed products thereof. Collection material.
5. A first step of irradiating the organic polymer molded body with ionizing radiation;
A second step in which a monomer having a cation exchange group and / or a chelate group is graft-polymerized on an organic polymer molded article;
Ion of metal selected from the group consisting of Co, Zn, Zr, Ni, Ti, Al, Fe, Mn and Cu and / or alkali metals of Li, Na, K to the graft polymerized organic polymer molded body A third step of contacting a solution containing the metal ion and adsorbing metal ions; and bringing the ferrocyanate solution into contact with the organic polymer molded body on which the metal ions are adsorbed to form an organic polymer molded body of the ferrocyanic acid metal salt. The manufacturing method of the radioactive substance collection material including the 4th process made to form on the surface and inside.
6). A first step of irradiating the organic polymer molded body with ionizing radiation;
A second step in which a monomer having an anion exchange group and / or a chelate group is graft-polymerized on an organic polymer molded article;
The third step of bringing the ferrocyanate solution into contact with the graft polymerized organic polymer molded article to adsorb ferrocyanide ions, and the organic polymer molded article adsorbing ferrocyanide ions to Co, Zn, Contacting a solution containing a metal ion selected from the group consisting of Zr, Ni, Ti, Al, Fe, Mn and Cu and / or an alkali metal of Li, Na and K, ferrocyanate metal salt is an organic polymer The manufacturing method of the radioactive substance collection material including the 4th process formed in the surface and inside of a molded object.
7). A first step of irradiating the organic polymer molded body with ionizing radiation;
A second step in which a monomer having a functional group convertible to a cation exchange group and / or a chelate group is graft-polymerized on an organic polymer molded body;
A third step of converting a functional group convertible to a cation exchange group and / or a chelate group into a cation exchange group and / or a chelate group;
Ion of metal selected from the group consisting of Co, Zn, Zr, Ni, Ti, Al, Fe, Mn and Cu and / or alkali metals of Li, Na, K to the graft polymerized organic polymer molded body A fourth step of contacting the solution containing the metal ions to adsorb metal ions, and contacting the ferrocyanate solution to the organic polymer molded body on which the metal ions are adsorbed to form the organic polymer molded body of the ferrocyanic acid metal salt. The manufacturing method of the radioactive substance collection material including the 5th process formed in the surface and inside of this.
8). A first step of irradiating the organic polymer molded body with ionizing radiation;
A second step in which a monomer having a functional group convertible to an anion exchange group and / or a chelate group is graft-polymerized on an organic polymer molded article;
A third step of converting a functional group convertible to an anion exchange group and / or a chelate group into an anion exchange group and / or a chelate group;
The fourth step of bringing the ferrocyanate solution into contact with the graft polymerized organic polymer molded article to adsorb ferrocyanide ions, and the organic polymer molded article adsorbed with ferrocyanide ions to Co, Zn, Contacting a solution containing a metal ion selected from the group consisting of Zr, Ni, Ti, Al, Fe, Mn and Cu and / or an alkali metal of Li, Na and K, ferrocyanate metal salt The manufacturing method of the radioactive substance collection material including the 5th process formed in the surface and the inside.
9. 9. The production method according to any one of 5 to 8, wherein the ferrocyanate solution is an aqueous solution of potassium ferrocyanate, sodium ferrocyanate or lithium ferrocyanate.
10. 10. The production method according to any one of 5 to 9 above, wherein the solution containing metal ions is an aqueous solution of metal hydrochloride, metal nitrate, metal phosphate, or metal sulfate.
11. The manufacturing method according to any one of 5 to 10 above, wherein the organic polymer molded body is selected from the group consisting of fibers, nonwoven fabrics, woven fabrics, twisted yarns, membranes, porous membranes, powders, or processed products thereof. .
12 The radioactive substance contained in the liquid, solid and / or gas by bringing the liquid, solid and / or gas containing the radioactive substance into contact with the radioactive substance collecting material according to any one of the above 1 to 3 A method for removing a radioactive substance, wherein the radioactive substance collecting material is adsorbed on the radioactive substance collecting material.
13. 5. A radiation protection article comprising the radioactive substance collecting material according to 4 above.

Hereinafter, the present invention will be described in detail.
The present invention is characterized in that a ferrocyanic acid metal salt is held between graft chains of an organic polymer molded article into which a graft chain having an ion exchange group and / or a chelate group is introduced by a radiation graft polymerization method. Related to radioactive material collection materials.

  In the present invention, the radiation graft polymerization method, which is a method of introducing a graft chain having an ion exchange group and / or a chelate group, irradiates a substrate with ionizing radiation such as γ rays or electron beams, This is a method of growing a graft chain from a base material by polymerizing a polymerizable monomer (hereinafter referred to as “monomer”) using radicals generated inside the base material. A characteristic of the radiation graft polymerization method is that radicals can be easily generated not only on the surface of the substrate but also inside the substrate by irradiation with radiation. Therefore, since the monomer can be polymerized not only on the substrate surface but also inside the substrate, the number of graft chains introduced into the substrate increases, and thus the number of functional groups introduced into the substrate also increases. .

  The term “graft” means “grafting” and represents a state in which one end of the graft chain is fixed to the base material and the other end is a free end that is not fixed. Since the graft chains have such morphological characteristics, small ions to large molecules can easily enter between the graft chains. This is a feature that is greatly different from that of an ion exchange resin having a crosslinked structure. In particular, when a fixed charge such as an ion exchange group or a chelate group is present in the graft chain, the fixed charges repel each other electrostatically, so that the graft chain extends and the graft chains repel each other. For this reason, a wide space is formed between the graft chains. Metal ions and ferrocyanide ions for forming a ferrocyanic acid metal salt, which will be described later, can easily enter the space between the graft chains thus formed. Adsorption onto the metal and formation of ferrocyanic acid metal salt fine particles occur.

  The organic polymer molding used as the base material used in the present invention is a commercially available product. For example, fibers, nonwoven fabrics, woven fabrics, twisted yarns, membranes, porous membranes, powders, and the like can be freely selected according to the application. Among these, since the fiber has a large surface area, a high adsorption rate can be expected when used as a radioactive material collection material. In addition to the twisted yarn that is a fiber assembly, the fiber can be easily formed into a sheet shape such as a nonwoven fabric or a woven fabric, and thus is suitable for the use of the present invention. In particular, if the type, location, abundance, usage environment, etc. of the radioactive material are significantly different from those in the normal state, such as the removal of radioactive material at the time of an accident at a radioisotope handling facility, change the usage method and mode of use. It is very advantageous that it can be freely selected or changed. Examples of the fiber material useful as a base material for the radioactive material collection material of the present invention include synthetic fibers, cellulose fibers such as cotton, animal fibers, mineral fibers, regenerated fibers, or mixed fibers thereof. . Synthetic fibers include polyester, polyamide, acrylic, polyvinyl chloride, polyvinylidene chloride, polyethylene, polypropylene, polyurethane, polyvinyl alcohol, fluorine, and the like. Cellulosic fibers include natural cellulose fibers such as cotton and hemp, viscose rayon, copper ammonia rayon, regenerated cellulose fibers such as polynosic, purified cellulose fibers such as tencel, and semi-synthetic fibers such as acetate and diacetate. It is. Mineral fibers include asbestos and basalt fibers. Animal fibers include animal hair fibers such as wool, silk and the like. The recycled fiber includes chitin / chitosan fiber, collagen fiber and the like. It is also possible to use blends of these fiber materials.

  The ion exchange group or chelate group present in the graft chain of the present invention is a functional group having a function of adsorbing ions contained in a liquid, solid or gas. It is an “ion exchange group” that adsorbs ions contained in a liquid, solid or gas, and desorbs other ions of the same sign that existed in the graft chain instead of the adsorbed ions, There are cation exchange groups and anion exchange groups. The “chelate group” simply adsorbs ions contained in a liquid, solid or gas. In the present invention, the ion exchange group or chelate group can directly adsorb radioactive substances that are ions. When the ion exchange group used is a cation exchange group, the cation exchange group plays a role of adsorbing the metal ion of the ferrocyanic acid metal salt to be adsorbed on the polymer molded body. And when the ion exchange group to be used is an anion exchange group, it plays the role which adsorb | sucks the ferrocyanide ion of the ferrocyanate metal salt which should be adsorb | sucked to a polymer molded object. The chelate group can adsorb metal ions or ferrocyanide ions depending on the type of chelate group used. Here, ferrocyanic acid metal salt is ferrocyanide ion:

Is an insolubilized metal salt formed with metal ions. When the ion exchange group to be used is a cation exchange group, the structure of the radioactive substance collection material of the present invention is schematically shown below:

It is expressed as And when the ion exchange group to be used is an anion exchange group, the structure of the radioactive substance collection material of this invention is typically the following:

It is expressed as
In the above formulas (I) and (II),

Part of, and

This part actually forms an insolubilized metal ferrocyanate and is held in the vicinity of the ion exchange group in the form of fine particles.
When a chelating group is used, there can be patterns of the above formulas (I) and (II) depending on the type of chelating group.

  As described above, it has been conventionally known that metal ferrocyanate has a property of adsorbing cesium. Therefore, the radioactive substance trapping material of the present invention retaining the ferrocyanic acid metal salt can adsorb cesium well.

  In the present invention, examples of the ion exchange group include a sulfonic acid group, a carboxyl group, a phosphate group, a quaternary ammonium group, and an amino group. Examples of the chelate group include an iminodiacetic acid group and a primary to tertiary amino group. Examples include one or more amino-based functional groups, amidoxime groups, and hydroxamic acid groups.

  Moreover, as a metal for forming a ferrocyanic acid metal salt, cobalt (Co), zinc (Zn), zirconium (Zr), nickel (Ni), titanium (Ti), aluminum (Al), iron (Fe), Manganese (Mn) and copper (Cu) and / or alkali metals of Li, Na and K are preferably used.

  Another aspect of the present invention relates to a method for producing a radioactive substance collection material of the present invention. The manufacturing method of the radioactive substance collection material of this invention changes with the kind of monomer graft-polymerized by the radiation graft polymerization method, and the kind of ion exchange group or chelate group.

  The first production method of the present invention includes a first step of irradiating ionizing radiation to an organic polymer molded body, a second step of graft-polymerizing a monomer having a cation exchange group and / or a chelate group to the organic polymer molded body, Ion of metal selected from the group consisting of Co, Zn, Zr, Ni, Ti, Al, Fe, Mn and Cu and / or alkali metals of Li, Na, K to the graft polymerized organic polymer molded body A third step of contacting a solution containing the metal ion and adsorbing metal ions; and bringing the ferrocyanate solution into contact with the organic polymer molded body on which the metal ions are adsorbed to form an organic polymer molded body of the ferrocyanic acid metal salt. It is a manufacturing method of the radioactive substance collection material including the 4th process formed in the surface and inside of this. This production method is carried out when a monomer having a cation exchange group and / or a chelate group is used as the monomer.

  In the first production method, the ionizing radiation applied to the organic polymer molded body includes α rays, β rays, γ rays, electron beams, neutron rays, etc. It is preferable to use γ rays and electron beams having the ability to transmit from the surface to a deep portion. The irradiation condition of radiation is not particularly limited, but in order to obtain sufficient graft efficiency in the next step, it is preferable to set it to 5 to 200 kGy, particularly 30 to 100 kGy in a deoxygenated state. At this time, the oxygen concentration may be a concentration at which graft polymerization can be achieved at a required polymerization rate, and is preferably 1% or less, more preferably 100 ppm or less.

  When the organic polymer molded body is irradiated with ionizing radiation, radicals are generated on the surface and inside of the organic polymer molded body. When a monomer having a cation exchange group and / or a chelate group is brought into contact therewith, the monomer having a cation exchange group and / or a chelate group is polymerized from the generated radical as a base point. The graft polymerization in the second step is divided into a pre-irradiation graft polymerization method and a simultaneous irradiation graft polymerization method depending on the timing of radiation irradiation. The present invention can employ either irradiation method. The pre-irradiation graft polymerization method is a polymerization method in which a base material is irradiated with radiation and then brought into contact with a monomer, and is generally suitable for a method for producing a separation material because the amount of homopolymer is small. . The simultaneous irradiation graft polymerization method is a graft polymerization method in which radiation is irradiated in the presence of a substrate and a monomer. In the present invention, it is more preferable to use a pre-irradiation graft polymerization method that produces a small amount of homopolymer (homopolymer).

  Here, the liquid phase graft polymerization method is used when the monomer to be contacted is a liquid, and the gas phase graft polymerization method is used when the monomer is a gas. In the present invention, any of the graft polymerization methods of liquid phase or gas phase graft polymerization can be used. That is, a liquid monomer can be brought into contact with the organic polymer molded body irradiated with radiation, or a gaseous monomer can be brought into contact therewith. It is also possible to perform an impregnation polymerization method. This method is a graft polymerization method in which a monomer amount is calculated in advance so that a predetermined graft ratio is obtained, and a necessary amount of monomer is immersed in an organic polymer molded body in advance.

  Examples of the monomer having a cation exchange group used in the first production method include acrylic acid, methacrylic acid, styrene sulfonic acid, vinyl sulfonic acid, methacryl sulfonic acid, allyl sulfonic acid, and alkali metal salts thereof. Examples of the monomer having a chelate group include maleic acid and vinylimidazole. In this specification, the term “monomer having a cation exchange group and / or a chelate group” means “a monomer having a cation exchange group or a monomer having a chelate group”, “a monomer having a cation exchange group and a chelate group” "And" a monomer having a cation exchange group and a monomer having a chelate group ".

  In order to carry out the graft polymerization efficiently, it is possible to use a crosslinking agent monomer such as divinylbenzene in combination. In addition, crosslinking agents such as triallyl isocyanate and ethylene glycol dimethacrylate can be used.

By graft polymerization, a graft chain having a cation exchange group and / or a chelate group is formed with the organic polymer molded body as a base point and the other end being a free end. Here, a solution containing a group of Co, Zn, Zr, Ni, Ti, Al, Fe, Mn and Cu and / or a metal ion (cation) selected from Li, Na and K alkali metals is brought into contact. Then, the metal ions on the cation exchange group and / or chelate group present in the graft chain are adsorbed. As a solution containing ions of a metal selected from the group consisting of Co, Zn, Zr, Ni, Ti, Al, Fe, Mn and Cu and / or an alkali metal of Li, Na, K, a metal hydrochloride of these metals, It is preferable to use an aqueous solution of metal nitrate, metal phosphate or metal sulfate. Finally, when the ferrocyanate solution is brought into contact with the organic polymer molded article on which the metal ions are adsorbed, the metal ions adsorbed first react with the ferrocyanide ions (anions), and the ferrocyanide ions (anions) react. A metal salt of Russian acid is generated and deposited on the surface and inside of the organic polymer molded body. It is preferable to use an aqueous solution of potassium ferrocyanate, sodium ferrocyanate or lithium ferrocyanate as the ferrocyanate solution to be brought into contact with the organic polymer molded article on which metal ions are adsorbed. Radioactive cesium is said to be trapped by the exchange of alkali metal in the ferrocyanide metal salt with cesium. Therefore, it is important to use an alkali metal (especially potassium). The insolubilized metal ferrocyanide is presumed to have a chemical form such as K ₂ Co [Fe (CN) ₆ ].
In addition, it is possible to incorporate a washing | cleaning process and a drying process suitably between each of said process 1-4.

  The second production method of the present invention includes a first step of irradiating an organic polymer molded article with ionizing radiation, and a second step of graft-polymerizing a monomer having an anion exchange group and / or a chelate group to the organic polymer molded article. The third step of bringing the ferrocyanate solution into contact with the graft polymerized organic polymer molded article to adsorb ferrocyanide ions, and the organic polymer molded article adsorbing ferrocyanide ions with Co, Zn Contacting a solution containing metal ions selected from the group consisting of Zr, Ni, Ti, Al, Fe, Mn and Cu and / or an alkali metal of Li, Na, K, and the metal ferrocyanate It is a manufacturing method of the radioactive substance collection material including the 4th process formed in the surface and inside of a molecular molded object. This production method is carried out when a monomer having an anion exchange group and / or a chelate group is used as the monomer.

  In the second production method, the step of irradiating the ionizing radiation to the organic polymer molded body is performed in the same manner as in the first production method. When the organic polymer molded body is irradiated with ionizing radiation, radicals are generated on the surface and inside of the organic polymer molded body. When a monomer having an anion exchange group and / or a chelate group is brought into contact therewith, the monomer having an anion exchange group and / or a chelate group is polymerized from the generated radical as a base point. As a result, a graft chain having an anion exchange group and / or a chelate group with the organic polymer molded body as the base point and the other end at the free end is formed. When a ferrocyanate solution is brought into contact therewith, ferrocyanide ions (anions) are adsorbed to anion exchange groups and / or chelate groups present in the graft chain. Finally, the organic polymer molded body on which ferrocyanide ions are adsorbed is selected from the group consisting of Co, Zn, Zr, Ni, Ti, Al, Fe, Mn and Cu and / or alkali metals of Li, Na and K When a solution containing metal ions (cations) is brought into contact, the ferrocyanide ions previously adsorbed react with metal ions to produce metal ferrocyanate, which is an organic polymer. It is deposited on the surface and inside of the compact.

  Here, in the formation of insolubilized metal ferrocyanide salt, in addition to the group consisting of Co, Zn, Zr, Ni, Ti, Al, Fe, Mn and Cu, particularly selected from alkali metals of Li, Na, K It is important to use metal ions together. For example, when an aqueous solution of potassium ferrocyanide or the like is brought into contact with the anion exchange group, ferrocyanate ions are ion-exchanged and adsorbed, but potassium ions important for improving the adsorption performance flow out. This is because the number of exchange sites for Cs in the insolubilized material is reduced even if the insoluble material is produced by bringing the cobalt into contact with each other to produce an insolubilized material of cobalt ferrocyanide or zinc ferrocyanide. Therefore, when a graft material having an anion exchange group and / or a chelate group is used, it is particularly important to use an alkali metal in combination with a polyvalent metal such as Co after adsorbing ferrocyanate ions.

In addition, as a monomer having an anion exchange group used in the second production method, vinylbenzyltrimethylammonium chloride, arylamine, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl Examples include methacrylate, N, N-dimethylacrylamide, and N, N-dimethylaminopropylacrylamide. Examples of the monomer having a chelate group include maleic acid and vinylimidazole. In the present specification, the term “monomer having an anion exchange group and / or a chelate group” means “a monomer having an anion exchange group or a monomer having a chelate group”, “a monomer having an anion exchange group and a chelate group” "And" monomers having an anion exchange group and a chelate group "are to be understood as representing all meanings.
In addition, it is possible to incorporate a washing | cleaning process and a drying process suitably between each of said process 1-4.

  In the third production method of the present invention, a first step of irradiating an organic polymer molded body with ionizing radiation, a monomer having a functional group that can be converted into a cation exchange group and / or a chelate group is used as the organic polymer molded body. Second step of graft polymerization, third step of converting a functional group that can be converted into a cation exchange group and / or a chelate group into a cation exchange group and / or a chelate group; First, a metal ion selected from the group consisting of Zn, Zr, Ni, Ti, Al, Fe, Mn, and Cu and / or a metal ion selected from Li, Na, and K alkali metals is contacted to adsorb the metal ions. 4 steps, and a fifth step in which the ferrocyanate solution is brought into contact with the organic polymer molded body on which metal ions are adsorbed to form a ferrocyanic acid metal salt on the surface and inside of the organic polymer molded body. This is a method for producing a radioactive substance collection material. This production method is carried out when a monomer having a functional group that can be converted into a cation exchange group and / or a chelate group is used as the monomer.

  In the third manufacturing method, the step of irradiating the organic polymer molded body with ionizing radiation is performed in the same manner as in the first manufacturing method. When the organic polymer molded body is irradiated with ionizing radiation, radicals are generated on the surface and inside of the organic polymer molded body. When a monomer having a functional group that can be converted to a cation exchange group and / or a chelate group is brought into contact therewith, a monomer having a functional group that can be converted to a cation exchange group and / or a chelate group is polymerized from the generated radical as a base point. . As a result, a graft chain having a functional group that can be converted into a cation exchange group and / or a chelate group with the organic polymer molded body as a base point and the other end at a free end is formed. Subsequently, the functional group which can be converted into a cation exchange group and / or a chelate group present in the graft chain is converted into a cation exchange group and / or a chelate group. Here, a solution containing a group of Co, Zn, Zr, Ni, Ti, Al, Fe, Mn and Cu and / or a metal ion (cation) selected from Li, Na and K alkali metals is brought into contact. Then, the metal ions on the cation exchange group and / or chelate group present in the graft chain are adsorbed. Finally, when the ferrocyanate solution is brought into contact with the organic polymer molded article on which the metal ions are adsorbed, the metal ions adsorbed first react with the ferrocyanide ions (anions), and the ferrocyanide ions (anions) react. An insolubilized product of a metal salt of Russian acid is formed and is deposited on the surface and inside of the organic polymer molded body.

In addition, as a monomer having a functional group that can be converted into a cation exchange group and / or a chelate group used in the third production method, acrylonitrile, acrolein, vinylpyridine, styrene, chloromethylstyrene, glycidyl methacrylate, glycidyl acrylate, glycidyl Examples include sorbate, glycidyl metaitaconate, glycidyl vinyl sulfonate, ethyl glycidyl maleate, 2-vinyl pyrrolidone, divinyl benzene, 1-vinyl-2-piperidone, N-vinyl-N-methylacetamide and derivatives thereof. Glycidyl methacrylate is particularly suitable because it can easily introduce various functional groups such as a sulfonic acid group, an amino group, and a chelate group. Styrene and chloromethylstyrene can also be suitably used because ion exchange groups and chelate groups can be easily introduced. For example, when glycidyl methacrylate is graft-polymerized on an organic polymer molded body and then sodium sulfite is reacted, the glycidyl group present in the graft chain is converted into a sulfone group (cation exchange group). In the present specification, the term “monomer having a functional group convertible to a cation exchange group and / or chelate group” means “a monomer having a functional group convertible to a cation exchange group or a chelate group” "Monomer having functional group", "Monomer having functional group convertible to cation exchange group and functional group convertible to chelate group" and "Monomer having functional group convertible to cation exchange group and chelate group" It should be understood as representing all the meanings of “monomers with possible functional groups”.
In addition, it is possible to incorporate a washing | cleaning process and a drying process suitably between each of said process 1-5.

  In the fourth production method of the present invention, a first step of irradiating an organic polymer molded body with ionizing radiation, a monomer having a functional group that can be converted into an anion exchange group and / or a chelate group is used as the organic polymer molded body. 2nd step of graft polymerization, 3rd step of converting functional group convertible to anion exchange group and / or chelate group into anion exchange group and / or chelate group, to graft polymerized organic polymer molded body, ferrocyan The fourth step in which an acid salt solution is contacted to adsorb ferrocyanide ions, and the organic polymer molded body on which ferrocyanide ions are adsorbed are coated with Co, Zn, Zr, Ni, Ti, Al, Fe, Mn and Cu. And a fifth step of forming a ferrocyanic acid metal salt on the surface and inside of the molded body by contacting with a solution containing a metal ion selected from the group consisting of and / or an alkali metal of Li, Na, K. A method for producing a morphism substance trapping material. This production method is carried out when a monomer having a functional group that can be converted into an anion exchange group and / or a chelate group is used as the monomer.

  In the fourth manufacturing method, the step of irradiating the organic polymer molded body with ionizing radiation is performed in the same manner as in the first manufacturing method. When the organic polymer molded body is irradiated with ionizing radiation, radicals are generated on the surface and inside of the organic polymer molded body. When a monomer having a functional group that can be converted to an anion exchange group and / or a chelate group is brought into contact therewith, a monomer having a functional group that can be converted to an anion exchange group and / or a chelate group is polymerized from the generated radical as a base point. . As a result, a graft chain having a functional group that can be converted into an anion exchange group and / or a chelate group with the organic polymer molded body as a base point and the other end at a free end is formed. Subsequently, the functional group which can be converted into a chelate group present in the graft chain is converted into an anion exchange group and / or a chelate group. When a ferrocyanate solution is brought into contact therewith, ferrocyanide ions (anions) are adsorbed to anion exchange groups and / or chelate groups present in the graft chain. Finally, the organic polymer molded body on which ferrocyanide ions are adsorbed is selected from the group consisting of Co, Zn, Zr, Ni, Ti, Al, Fe, Mn and Cu and / or alkali metals of Li, Na and K When a solution containing metal ions (cations) is brought into contact, the ferrocyanide ions previously adsorbed react with the metal ions to produce insolubilized metal ferrocyanate, which is It is deposited on the surface and inside of the organic polymer molded body. The importance of using an alkali metal is as described in the second production method.

In addition, as a monomer having a functional group that can be converted into an anion exchange group and / or a chelate group used in the fourth production method, acrylonitrile, acrolein, vinylpyridine, styrene, chloromethylstyrene, glycidyl methacrylate, glycidyl acrylate, glycidyl Examples include sorbate, glycidyl metaitaconate, glycidyl vinyl sulfonate, ethyl glycidyl maleate, 2-vinyl pyrrolidone, divinyl benzene, 1-vinyl-2-piperidone, N-vinyl-N-methylacetamide and derivatives thereof. Glycidyl methacrylate is particularly suitable because it can easily introduce various functional groups such as a sulfonic acid group, an amino group, and a chelate group. Styrene and chloromethylstyrene can also be suitably used because ion exchange groups and chelate groups can be easily introduced. For example, when chloromethylstyrene is graft-polymerized on an organic polymer molded body and then reacted with trimethylamine, the chloromethyl group present in the graft chain is converted to a quaternary ammonium group (anion exchange group). In the present specification, the term “monomer having a functional group convertible to an anion exchange group and / or chelate group” means “a monomer having a functional group convertible to an anion exchange group or a chelate group” "Monomer having functional group", "Monomer having functional group convertible to anion exchange group and functional group convertible to chelate group" and "Monomer having functional group convertible to anion exchange group and chelate group" It should be understood as representing all the meanings of “monomers with possible functional groups”.
In addition, it is possible to incorporate a washing | cleaning process and a drying process suitably between each of said process 1-5.

  The radioactive material collection material of the present invention thus produced adsorbs insolubilized metal ferrocyanate, while ion exchange groups and / or chelate groups are present, so that insolubilized metal ferrocyanate is insolubilized. In addition to radioactive cesium adsorbed by substances, many radioactive substances such as radioactive strontium and radioactive iodine can be collected. Therefore, by bringing the radioactive substance-collecting material of the present invention into contact with a liquid, solid, and / or gas containing the radioactive substance, the radioactive substance contained in the liquid, solid, and / or gas is used as the radioactive substance-collecting material. It can be removed by adsorption. A radiation protection article can be manufactured using such a characteristic of the radioactive substance collection material of the present invention. Examples of radiation protection products include bags and containers for storing articles that can be affected by radioactive substances, as well as items to be worn such as radiation protection clothes, masks, shoes, or bags. It is also possible to create a curtain for collecting radioactive substances diffused in the air or a fence for collecting radioactive substances diffused in seawater by using the substance collecting material.

Next, a typical example of the radioactive substance collection material of the present invention will be described below.
For example, a radioactive material trapping material in which an insolubilized ferrocyanic acid metal salt is deposited on a part of an organic polymer molded article having a graft chain in which a sulfonic acid group is present as a typical ion exchange group can be mentioned. A commercially available polyethylene fiber material or nylon fiber material can be used as the organic polymer molded body. The polyethylene fiber material or nylon fiber material is irradiated with 200 kGy of γ rays to generate radicals on the surface and inside of the fiber, and then glycidyl methacrylate is graft-polymerized as a monomer that can be converted into an ion exchange group. Thereby, the graft ratio of 100% or more can usually be achieved. Next, when the glycidyl group present in the graft chain is sulfonated with a sodium sulfite solution, a cation exchange fiber material having an ion exchange capacity of 2.0 meq / g or more can be easily obtained. Since the graft chain is introduced using the radiation graft polymerization method, the sulfonic acid group which is a cation exchange group is introduced not only into the surface layer of the fiber but also into the inside. When this material is brought into contact with, for example, a 1% aqueous solution of cobalt chloride containing cobalt ions as metal ions, some of the sulfonic acid groups are sodium ion type (Na ⁺ type) and the rest are cobalt ion type (Co ²⁺ type). The resulting fiber material is obtained. When a 2% potassium ferrocyanate aqueous solution is brought into contact with this fiber material, cobalt ions and ferrocyanide ions existing in the fiber material react with each other, and cobalt ferrocyanate or a part of cobalt ferrocyanate is Na. And insolubilized substances replaced by K ions are deposited. At this time, as described above, cobalt ions are present not only in the surface layer of the fiber material but also in the interior, so the insolubilized material in which a part of cobalt ferrocyanate or cobalt ferrocyanate is replaced with Na or K ions, Not only the surface layer of the fiber material but also the inside is firmly held. The insolubilized material present in the fiber material has an ability to adsorb cesium ions. On the other hand, the partially present Na ⁺ type and potassium ion type (K ⁺ type) sulfonic acid groups can simultaneously adsorb other radioactive substances such as strontium. The K ⁺ -type sulfonic acid group is obtained by exchange adsorption of K + ions supplied from potassium chloride coexisting with potassium ferrocyanide and cobalt chloride.

  The amount of sulfonic acid groups to be introduced and the amount of insolubilized material in which cobalt ferrocyanate or a part of cobalt ferrocyanate is replaced by Na or K ions are the type of radioactive material to be collected, the location of the radioactive material The amount can be determined as appropriate according to the abundance and the environment in which the radioactive material collection material is used. For example, when a lot of radioactive cesium should be removed, by adjusting the amount of cobalt ions, potassium ferrocyanate or sodium ferrocyanate aqueous solution, a part of cobalt ferrocyanate or cobalt ferrocyanate may be Na or What is necessary is just to enlarge the holding | maintenance amount of the insolubilized substance replaced with K ion. If the concentration of radioactive cesium is not so high, by reducing the amount of cobalt ion, potassium ferrocyanate or sodium ferrocyanate aqueous solution, cobalt ferrocyanate or cobalt ferrocyanate may be partially Na or K ion. The retention amount of the insolubilized material replaced with may be reduced. Since this insolubilized material is retained as very fine particles between the graft chains, it can be used as a fine particle fixing material for adsorbent use. Conventional coagulation-precipitation treatment is unnecessary, and other radioactive substances such as radioactive strontium can be removed using ion exchange groups.

  As described above, the case where the sulfonic acid group is used as the cation exchange group has been described. In addition, a carboxyl group, a phosphoric acid group, an amidoxime group, a hydroxamic acid group, an iminodiacetic acid group, and the like can also be suitably used. It is also possible to combine a plurality of these functional groups.

Next, a radioactive substance trapping material in which ferrocyanic acid metal salt particles are deposited on a part of an organic polymer molded body having a graft chain in which a quaternary ammonium group is present as a typical anion exchange group will be described. A commercially available polyethylene fiber material or nylon fiber material can be used as the organic polymer molded body. A polyethylene fiber material or nylon fiber material is irradiated with 10 to 200 kGy of γ rays to generate radicals on the surface and inside of the fiber, and then chloromethylstyrene is graft-polymerized as a monomer that can be converted into an ion exchange group. Thereby, the graft ratio of 60% or more can usually be achieved. Next, when the chloromethyl group present in the graft chain is quaternized with a trimethylamine aqueous solution, an anion exchange fiber material having an ion exchange capacity of 1.5 meq / g or more can be easily obtained. When this material is brought into contact with a 1% potassium ferrocyanate aqueous solution, an anion exchange fiber material in which ferrocyanide ions are adsorbed on a part of the quaternary ammonium group is obtained. Next, when this material is brought into contact with an aqueous solution containing 2% copper chloride and 3.5% potassium chloride, the ferrocyanide ions and copper ions present in the fibers react to produce copper ferrocyanate and ferrocyanide. A ferrocyanic acid metal salt insolubilized product in which a part of copper oxide is replaced by K + ions is deposited. As explained above, this fiber material is composed of copper ferrocyanate and insoluble matter of ferrocyanate metal salt in which a part of copper ferrocyanate is replaced with K + ions in the form of ultrafine particles only on the surface layer of the fiber material. It will also be held firmly inside. Some of the quaternary ammonium groups in the fiber material are present in Cl ⁻ form. The copper ferrocyanate present in this fiber material has the ability to adsorb cesium ions, while the Cl ⁻ type quaternary ammonium group can collect iodine ions.

  The amount of quaternary ammonium group to be introduced and the amount of ferrocyanate metal salt insolubilized material in which copper ferrocyanate and part of copper ferrocyanate are replaced with K + ions are the type of radioactive material to be collected, radioactive material It can be determined as appropriate according to the location and amount of occurrence of the material and the use environment of the radioactive material collection material. For example, if much radioactive cesium is to be removed, increase the amount of potassium ferrocyanate or sodium ferrocyanate aqueous solution and increase the amount of copper chloride and potassium chloride aqueous solution to increase the amount of copper ferrocyanate and ferrocyanic acid. What is necessary is just to enlarge the holding | maintenance amount of the fine particle of the insoluble matter of the ferrocyanic acid metal salt in which a part of copper was replaced by K + ion. If the concentration of radioactive cesium is not so high, reduce the amount of potassium ferrocyanate or sodium ferrocyanate aqueous solution and reduce the amount of copper chloride and potassium chloride mixed aqueous solution to reduce the amount of copper ferrocyanate and ferrocyanic acid. What is necessary is just to make small the holding | maintenance amount of the insolubilization thing of the ferrocyanic acid metal salt which a part of copper replaced by K + ion. As mentioned above, the insolubilized material is retained between the graft chains as very fine particles.

  In the above, the case where a quaternary ammonium group is used as an anion exchange group has been particularly described. In addition, amino functional groups containing single or plural amino acid groups and primary to tertiary amino groups, for example, functional groups such as polyethyleneimine. Can also be suitably used. It is also possible to combine a plurality of these functional groups.

  In the above example of the production method using the cation exchange group, the metal supported on the ion exchange group and / or chelate group for the formation of the ferrocyanate metal salt insolubilized material is cobalt, copper, Zn, Zr, Ni , Ti, Al, Fe, Mn and / or Li, Na, K alkali metals. In order to adsorb these metals to ion exchange groups and / or chelate groups, hydrochlorides, nitrates, phosphates or sulfates of these metals can be preferably used.

  In the above production method example, when the ferrocyanate solution (potassium ferrocyanate or sodium ferrocyanate aqueous solution) is brought into contact with the metal ions adsorbed on the graft chain, the metal ions are separated from the ion exchange groups, It produces ferrocyanic acid metal salts in situ. That is, the metal ions present in the graft chain come into contact with the ferrocyanide ions that have diffused into the graft chain, forming a slightly soluble salt on the spot to form fine particles, and at the same time, converting the cation exchange group to an alkali metal salt. Change the type, and change the anion exchange group to Cl type, nitric acid type or sulfuric acid type. As a result, the ferrocyanic acid metal salt is held between the graft chains in the form of ultrafine particles without aggregating with each other. When the graft chain of the radioactive material collection material of the present invention is a cation exchange group, the graft chain is negatively charged, and when the anion exchange group is positively charged, the graft chains repel each other, Intertwining between graft chains is suppressed. Therefore, when a radioactive substance-containing material produced by these production methods is brought into contact with a liquid, solid and / or gas containing a radioactive substance, the contained radioactive substance (for example, radioactive cesium etc.) Can be quickly diffused and is adsorbed by the organic polymer molded body.

  As described above, an aqueous solution of an alkali metal salt such as potassium ferrocyanate or sodium ferrocyanate, and in some cases lithium ferrocyanate can be suitably used as the ferrocyanate solution. These alkali metal salts are easily soluble in water and easy to use.

  In this way, the radioactive material collection material of the present invention in which the ferrocyanate metal salt fine particles are confined in the fiber is more ferrocyanate than the material in which the ferrocyanate metal salt is supported on a carrier such as activated carbon or silica gel. The amount of metal salt supported increases. In addition, since the ferrocyanic acid metal salt is firmly held in the graft chain in the form of fine particles, it hardly falls off from the radioactive material collection material. The radioactive substance collection material of the present invention includes a radioactive cesium adsorption function by the retained ferrocyanic acid metal salt, and ion exchange groups and / or chelate groups of radioactive strontium and radioactive iodine remaining in the radioactive substance collection material. It can be used as a composite material having both the adsorption function and the collection function of various radionuclides.

  Thus, the radioactive substance in the contaminated area can be removed by taking out the radioactive substance-collecting material of the present invention adsorbed with the radioactive substance such as radioactive cesium, strontium, and iodine from the contaminated area. Since the radioactive material collection material of the present invention is in the form of fibers or fiber aggregates, operations for solid-liquid separation that are essential in the conventional methods such as coagulation sedimentation and filtration are not required. . The material of the present invention can be easily recovered by throwing the radioactive material collecting material of the fiber or the fiber assembly of the present invention as it is into a place contaminated with the radioactive material and adsorbing the radioactive material as the contamination source. Therefore, it is possible to quickly respond to radioactive material contamination accidents.

  The organic polymer molded body used in the production method of the present invention is preferably a twisted yarn, a woven fabric or a non-woven fabric, which is an aggregate of fibers or fibers, and has a surface area per unit weight that is overwhelmingly larger than that of a resin, The adsorption rate can be increased, which is extremely advantageous. This is because the fiber has many voids, so that the pressure loss is small, and the liquid, solid and / or gas containing the radioactive substance can be passed at high speed. Even when the radioactive substance trapping material of the present invention is used in a manner of filling a column, a liquid, solid and / or gas containing the radioactive substance can be passed at a high flow rate. Moreover, the radioactive substance collection material of this invention can be processed also in the form of textiles, such as a film, a porous membrane, a net | network, powder, or a molding. The ion exchange capacity per unit volume of the radioactive substance collection material of the present invention cannot be said to be large compared with that of commercially available ion exchange resins. However, since the radioactive substance is extremely small in concentration, it is considered that the amount of the functional group is sufficient for removing the radioactive substance in the liquid, solid and / or gas containing such a trace amount of radioactive substance. It is done. On the other hand, the collection material using the radiation graft polymerization method is not only a surface modification, but an ion exchange group is introduced into the material and the ferrocyanic acid metal salt is retained. It can be said that this is advantageous.

Examples of the present invention will be described below, but the embodiments of the present invention are not limited to the following examples.
[Example 1]
(1) Production of strongly acidic cation exchange fiber 1 kg of 6-nylon fiber twisted yarn having a diameter of about 25 μm was put in a polyethylene bag, and the nitrogen substitution operation of evacuation and introduction of nitrogen gas was repeated three times. This bag was placed in a foamed polystyrene box together with 5 kg of dry ice, and the foamed polystyrene box was irradiated with γ rays of 200 kGy under cooling. After irradiation, the nylon fiber twisted yarn in the polyethylene bag was taken out and placed in a glass ampoule for graft polymerization. A 10% aqueous solution of sodium styrenesulfonate (Nacalai Tesque) that had been deoxygenated beforehand by bubbling with nitrogen gas was introduced into a glass ampoule. Then, graft polymerization was performed in a constant temperature water bath at 40 ° C. for 5 hours. The twisted yarn after the polymerization was immersed in pure water at 50 ° C. and washed for 1 hour. This washing operation was repeated twice. When the twisted yarn after washing was vacuum-dried and the weight was measured, it was found that the graft ratio was 61%.

A portion of 0.5 g of this twisted yarn was sampled and dipped in 100 ml of 1N hydrochloric acid to regenerate. The twisted yarn was washed with pure water until the PH test paper showed no acidity. This twisted yarn was immersed in 100 ml of a 3% sodium chloride aqueous solution for 30 minutes and stirred. A portion of the acidified solution was titrated with a 1N aqueous sodium hydroxide solution to determine the neutral salt decomposition capacity. Thus, a twisted yarn composed of a strongly acidic cation exchange fiber having an ion exchange capacity of 1.76 meq / g was obtained.
(2) Manufacture of cobalt ferrocyanate-carrying nylon fiber twisted yarn 2g of cobalt (II) chloride hexahydrate was dissolved in water to make 100ml of 2% cobalt chloride aqueous solution, and 1g of the twisted yarn obtained in (1) Soaked. After 30 minutes, the twisted yarn was taken out from the cobalt chloride aqueous solution and thoroughly washed with pure water. The twisted yarn after drying was pink, and it was found that cobalt ions were adsorbed on the twisted yarn. Next, 100 ml of a 1% potassium ferrocyanate aqueous solution was prepared in a beaker, and a twisted yarn adsorbed with cobalt ions was immersed therein. While stirring at room temperature for 1 hour, cobalt ferrocyanate was supported on the twisted yarn. Finally, the twisted yarn was washed 5 times with 100 ml of pure water, and it was confirmed that the washing liquid became transparent. The twisted yarn was vacuum dried at 60 ° C. to obtain a nylon fiber twisted yarn carrying cobalt ferrocyanate.

[Example 2]
Manufacture of iron (III) ferrocyanate salt-supported nylon fiber twisted yarn In the process of Example 1 (2), 2 g of iron (III) chloride hexahydrate was used instead of 2 g of cobalt chloride (II) hexahydrate. A nylon fiber twisted yarn adsorbed with a metal salt was prepared and immersed in a 1% aqueous solution of potassium ferrocyanate described in Example 1 (2), and the same operation as in Example 1 was performed. In this manner, a nylon fiber twisted yarn carrying iron (III) ferrocyanate was obtained.

[Example 3]
Manufacture of manganese (II) ferrocyanate salt-supported nylon fiber twisted yarn In the process of Example 1 (2), 2 g of manganese chloride tetrahydrate was used instead of 2 g of cobalt chloride (II) hexahydrate, After producing a nylon fiber twisted yarn adsorbed with a metal salt, it was immersed in a 1% potassium ferrocyanate aqueous solution described in Example 1 (2), and the same operation as in Example 1 was performed. In this way, a nylon fiber twisted yarn carrying manganese (II) ferrocyanate was obtained.

[Example 4]
Production of Ferrocyanic Acid Copper Salt-Supported Nylon Fiber Twist Yarn In the process of Example 1 (2), instead of 2 g of cobalt chloride (II) hexahydrate, 2 g of copper chloride (II) dihydrate was used. After producing a nylon fiber twisted yarn adsorbed with a metal salt, it was immersed in a 1% potassium ferrocyanate aqueous solution described in Example 1 (2), and the same operation as in Example 1 was performed. In this way, a nylon fiber twisted yarn carrying a ferrocyanic acid copper salt was obtained.

[Example 5]
Preparation of nylon ferrocyanate-supported nylon fiber twisted yarn In the process of Example 1 (2), instead of 2 g of cobalt chloride (II) hexahydrate, 2 g of nickel chloride hexahydrate was used. After producing the adsorbed nylon fiber twisted yarn, it was immersed in a 1% potassium ferrocyanate aqueous solution described in Example 1 (2), and the same operation as in Example 1 was performed. In this way, a nylon fiber twisted yarn carrying a ferrocyanic acid nickel salt was obtained.

[Example 6]
Manufacture of zinc ferrocyanate-carrying nylon fiber twisted yarn In the process of Example 1 (2), 2 g of anhydrous zinc chloride was used instead of 2 g of cobalt (II) chloride hexahydrate, and the nylon fiber twisted yarn adsorbed with metal salt Then, the sample was immersed in a 1% aqueous solution of potassium ferrocyanate described in Example 1 (2), and the same operation as in Example 1 was performed. In this way, a nylon fiber twisted yarn carrying a ferrocyanic acid zinc salt was obtained.

[Example 7]
Manufacture of ferrocyanic acid titanium salt-carrying nylon fiber twisted yarn In the process of Example 1 (2), instead of 2 g of cobalt (II) chloride hexahydrate, 10 ml of 20% aqueous solution of titanium chloride was used to absorb the metal salt. After producing the fiber twisted yarn, it was immersed in a 1% potassium ferrocyanate aqueous solution described in Example 1 (2), and the same operation as in Example 1 was performed. In this way, a nylon fiber twisted yarn carrying a ferrocyanic acid titanium salt was obtained.

[Example 8]
Manufacture of nylon ferrocyanate salt-supported nylon fiber yarn Adsorption of metal salt in the process of Example 1 (2) using 10 g of aluminum sulfate 18 hydrate instead of 2 g of cobalt (II) chloride hexahydrate After the produced nylon fiber twisted yarn was produced, it was immersed in a 1% aqueous solution of potassium ferrocyanate described in Example 1 (2), and the same operation as in Example 1 was performed. In this way, a nylon fiber twisted yarn carrying an aluminum ferrocyanate was obtained.

[Example 9]
Manufacture of ferrocyanic acid zirconium salt-supported nylon fiber twisted yarn In the process of Example 1 (2), 10 g of zirconium oxychloride octahydrate was used in place of 2 g of cobalt (II) chloride hexahydrate to adsorb the metal salt. After the produced nylon fiber twisted yarn was produced, it was immersed in a 1% aqueous solution of potassium ferrocyanate described in Example 1 (2), and the same operation as in Example 1 was performed. In this way, a nylon fiber twisted yarn carrying a ferrocyanic acid zirconium salt was obtained.

[Adsorption test]
(1) Cesium adsorption test in aqueous sodium chloride solution Sodium chloride was dissolved in pure water to prepare 0.5 mol / L artificial seawater. To this solution, cesium chloride was added so as to have a cesium concentration of 10 mg / L, and a test solution for evaluating each nylon fiber twisted yarn was obtained. To 30 ml of this sodium chloride aqueous solution, 0.3 g of each ferrocyanic acid metal salt-carrying nylon fiber twisted yarn prepared in Examples 1 to 9 was added and stirred for 24 hours to adsorb cesium. Then, the cesium collection performance of each nylon fiber twisted yarn was investigated by measuring the cesium density | concentration in sodium chloride aqueous solution. These results are shown in Table 1. Cesium removal performance of all nylon fiber twisted yarns was recognized. In particular, a twisted yarn carrying a metal salt of cobalt ferrocyanate, manganese ferrocyanate, nickel ferrocyanate, and zinc ferrocyanate has a cesium content of 0.1 mg / L or less and a high cesium removal rate of 99%. showed that.

(2) Cesium and strontium adsorption test in sodium chloride aqueous solution In the above cesium adsorption test, except that strontium chloride aqueous solution was added to cesium (10 mg / L) to a strontium concentration of 10 mg / L. The same collection test as in (1) was performed. The results are shown in Table 2.

  From Tables 1 and 2, it can be seen that the radioactive substance collection material of the present invention has the ability to effectively collect strontium in addition to cesium. And each nylon fiber twisted yarn after collecting cesium and strontium was removed with tweezers, and the radioactive substance could be easily removed from the aqueous solution containing the radioactive substance.

[Examples 10 to 18]
(1) Production of Strongly Basic Anion Exchange Fiber 50 g of a woven fabric made of polyethylene fiber having a fiber diameter of 17 μm was put in a polyethylene bag, and a nitrogen substitution operation of evacuation-nitrogen gas introduction was repeated three times. This bag was irradiated with a 4 MeV electron beam of 200 kGy. After the irradiation, the irradiated polyethylene fiber woven fabric was put in a foamed polystyrene box as a bag, and dry ice was also put therein and stored at a low temperature. On the other hand, 1 L of chloromethylstyrene (manufactured by AGC Seimi Chemical Co., Ltd.) was passed through 500 ml of an activated alumina-filled column to remove the polymerization inhibitor contained in chloromethylstyrene. Nitrogen was bubbled through the chloromethylstyrene to deoxygenate. The irradiated polyethylene fiber woven fabric was put into a glass ampule and sucked with a vacuum pump for 10 minutes to evacuate the glass ampule. The decarbonized chloromethylstyrene solution was charged into the ampoule using a vacuum. Graft polymerization was performed in a constant temperature water bath at 45 ° C. for 6 hours. After the polymerization, the polyethylene fiber woven fabric was taken out, washed with acetone and methanol, and then weighed. From the weight increase rate, it was found that the graft ratio of chloromethylstyrene was 116%. The polyethylene fiber woven fabric after the graft polymerization was immersed in a 5% trimethylamine aqueous solution and placed in a constant temperature water bath at 40 ° C. for 3 hours to perform a quaternary ammonium reaction. The obtained polyethylene fiber woven fabric was strongly basic anion exchange having a neutral salt decomposition capacity of 2.4 meq / g.

(2) Production of ferrocyanic acid metal salt-supported polyethylene fiber woven fabric The woven fabric obtained in (1) was immersed in a 2% aqueous potassium ferrocyanate solution for 1 hour to adsorb ferrocyanide ions to the woven fabric. This polyethylene fiber woven fabric adsorbed with ferrocyanide ions was immersed in a hydrochloride aqueous solution of each metal salt of cobalt, iron, manganese, copper, nickel, zinc, titanium, aluminum and zirconium described in Examples 1 to 9 for 1 hour. Then, the insolubilized metal ferrocyanate was held in the polyethylene fiber woven fabric.

  The cesium and iodine ion adsorption test using each polyethylene fiber woven fabric thus obtained was performed in accordance with the cesium and strontium adsorption test in the above sodium chloride aqueous solution. The results are shown in Table 3. Each polyethylene fiber woven fabric effectively collected cesium and iodine ions.

[Examples 19 to 21]
(1) Production of chelate fiber The nylon fiber twisted yarn used in Example 1 was used and irradiated with radiation in the same manner as in Example 1. This was brought into contact with glycidyl methacrylate / methanol as a monomer solution, and graft polymerization was carried out for 7 hours. The graft rate was 129%. Next, the nylon fiber twisted yarn after the graft polymerization was immersed in a solution of sodium iminodiacetate / isopropyl alcohol / water = 1/1/8 and reacted at 80 ° C. for 10 hours. From the weight increase rate of the twisted yarn, it was found that a chelate fiber having 2.7 mmol / g iminodiacetic acid group could be prepared.

  The nylon fiber twisted yarn was brought into contact with an aqueous solution of cobalt chloride, an aqueous solution of manganese chloride and an aqueous solution of nickel chloride in the same manner as in Example 1, Example 3, and Example 5 to adsorb ions of each metal. Furthermore, the ferrocyanic acid metal salt carrying | support nylon fiber twisted yarn was obtained by making it contact with potassium ferrocyanate aqueous solution similarly to each of these Examples.

[Adsorption test]
Cesium and strontium adsorption test The nylon fiber twisted yarns obtained in Examples 19 to 21 were subjected to a cesium and strontium adsorption test in the same manner as the cesium and strontium adsorption test in the above sodium chloride aqueous solution. The results are shown in Table 4.

[Example 22]
(1) Production of Weakly Basic Anion Exchange Fiber The nylon fiber twisted yarn used in Example 1 was used and irradiated in the same manner as in Example 1. A 20% aqueous solution of N, N-dimethylaminoethyl methacrylate was brought into contact therewith as a monomer solution, and graft polymerization was carried out for 4 hours. The graft ratio was 46%. Next, the nylon fiber twisted yarn after the graft polymerization was treated with a 0.5N hydrochloric acid aqueous solution. Next, it was immersed in a 2% aqueous potassium ferrocyanate solution for 1 hour to adsorb ferrocyanide ions on the woven fabric. The anion exchange fiber twisted yarn adsorbing the ferrocyanide ions was immersed in a 3% aqueous solution of cobalt chloride to produce and hold crystals containing cobalt ferrocyanate as a main component. At this time, three types of fibers were prepared with 0%, 1.9%, and 3.3% potassium chloride in the cobalt chloride solution.
The cesium ion adsorption test using the fiber thus obtained was carried out in the same manner as in Example 1. However, cesium ions were dissolved in pure water without adding sodium chloride. The results are shown in Table 5.

In the fiber production process, it can be seen that the sample without adding the KCl solution has a bad cesium removal rate of about 60%, and when the KCl solution is added, the cesium removal effect improves as the amount of addition increases.
[Examples 23 to 31]

  In Examples 10 to 18, in addition to the hydrochloride aqueous solution of each metal salt of cobalt, iron, manganese, copper, nickel, zinc, titanium, aluminum, and zirconium, a solution adjusted to 1.5% potassium chloride was used. The same cesium ion adsorption test was conducted. The results are shown in Table 6.

  Ion exchange groups and chelates were introduced into organic polymer moldings of various shapes and materials, particularly fiber materials or fiber aggregates having a large surface area and easy to mold using a radiation graft polymerization method. And using ferrocyanate and various metals such as cobalt, iron, manganese, nickel, it was found that metal ferrocyanate can be deposited on the fiber, and cesium, strontium, iodine, etc. can be easily removed. . By using the trapping material of the present invention in a nuclear facility, it is possible to prevent the diffusion of radioactive substances while minimizing exposure. In addition, the radioactive material collection material of the present invention in the form of fibers or fiber aggregates can be used not only for polluted water in nuclear power plants, but also when removing radioactive materials already released into the environment. There is an advantage that it can be easily processed into various product forms in consideration of the type, concentration, existence form, and the like. Since the radioactive substance collection material of the present invention is light in weight, it can be easily transferred and transported, and further subjected to final disposal such as volume reduction and solidification.

Claims (5)

A first step of irradiating the organic polymer molded body with ionizing radiation;
A second step in which a monomer having an anion exchange group is graft-polymerized to the organic polymer molded article;
A third step in which a ferrocyanate solution is brought into contact with the graft polymerized organic polymer molded article to adsorb ferrocyanide ions; and the organic polymer molded article adsorbed with the ferrocyanide ions is coated with Co, A metal ion selected from the group consisting of Zn, Zr, Ni, Ti, Al, Fe and Mn, and a solution containing K ions are brought into contact with each other, and a ferrocyanic acid metal salt is added to the surface of the organic polymer molded body and A method for producing a radioactive substance collection material, comprising a fourth step formed inside. A first step of irradiating the organic polymer molded body with ionizing radiation;
A second step of graft-polymerizing a monomer having a functional group convertible to an anion exchange group onto an organic polymer molded body;
A third step of converting the functional group convertible to the anion exchange group into an anion exchange group;
A fourth step in which a ferrocyanate solution is brought into contact with the graft polymerized organic polymer molded body to adsorb ferrocyanide ions, and the organic polymer molded body on which the ferrocyanide ions are adsorbed is coated with Co. A metal ion selected from the group consisting of Zn, Zr, Ni, Ti, Al, Fe and Mn, and a solution containing K ions are contacted, and the ferrocyanic acid metal salt is applied to the surface of the organic polymer molded body . And a fifth step of forming the radioactive material trapping material inside. The production method according to claim 1 or 2 , wherein the ferrocyanate solution is an aqueous solution of potassium ferrocyanate, sodium ferrocyanate, or lithium ferrocyanate. The method according to any one of claims 1 to 3 , wherein the solution containing metal ions is an aqueous solution of metal hydrochloride, metal nitrate, metal phosphate, or metal sulfate. The said organic polymer molded object is selected from the group which consists of a fiber, a nonwoven fabric, a woven fabric, a twisted thread, a film | membrane, a porous membrane, a powder, or those processed goods, The any one of Claims 1 thru | or 4 Production method.