JP5675583B2 - Method for removing radioactive iodine and radioactive cesium and hydrophilic resin composition for removing radioactive iodine and radioactive cesium - Google Patents

Description

  The present invention relates to a method capable of removing both radioactive iodine and radioactive cesium present in radioactive liquid waste and / or radioactive solids generated from nuclear power plants and spent nuclear fuel facilities, and radioiodine and radioactive cesium suitable for the method. It is related with the hydrophilic resin composition which shows the function to fix all.

Currently, widely used nuclear power plants involve the production of significant amounts of radioactive by-products due to nuclear fission in the reactor. The main ones of these radioactive materials are fission products and active elements containing extremely dangerous radioactive isotopes such as radioactive iodine, radioactive cesium, radioactive strontium and radioactive cerium. Among these, since radioactive iodine becomes a gas at 184 ° C, it is very likely to be released when inspecting and replacing nuclear fuel, and for other reasons such as accidents when handling nuclear fuel and accidents such as reactor runaway accidents. There is a danger. The main radioactive iodines are long-lived iodine 129 (half-life: 1.57 years × 10 ⁷ ) and short half-life iodine 131 (half-life: 8.05 days). Here, normal iodine that does not exhibit radioactivity is a trace element essential for the human body, and is collected in the thyroid gland near the throat and becomes a component of growth hormone. For this reason, if radioactive iodine is taken in through breathing, water, or food, it is collected in the thyroid gland just like normal iodine and increases internal radiation exposure. Don't be.

  In addition, radioactive cesium is one of metals that have a melting point of 28.4 ° C. and is in a liquid state at around room temperature, and is very easily released like radioactive iodine. The target radioactive cesium is mainly cesium 134 having a relatively short half-life (half-life: 2 years) and cesium 137 having a long half-life (half-life: 30 years). In particular, cesium 137 not only has a long half-life, but also emits high-energy radiation and has a property of being highly soluble in water because it is an alkali metal. Furthermore, since radioactive cesium is easily absorbed by the human body through breathing and skin, and is dispersed almost uniformly throughout the body, human health damage is serious.

  For this reason, when radioactive cesium is accidentally released from reactors operating around the world due to unforeseen reasons, not only radioactive contamination to workers working in the reactor and neighboring residents, but also due to air There is concern that a wider range of radioactive contamination will be caused to humans and animals through food and water contaminated by the radioactive cesium being carried. The danger in this regard has been clearly demonstrated by the Chernobyl nuclear power plant accident.

  For such a situation, as a treatment method of the generated radioactive iodine, a washing treatment method, a physical / chemical treatment method by filling a solid adsorbent using fibrous activated carbon or the like (see Patent Documents 1 and 2), ions Treatment with an exchange agent (see Patent Document 3) and the like have been studied.

  However, any of the above-described methods has problems, and development of a method for removing radioactive iodine in which these problems are solved is desired. First, there are alkali cleaning methods and the like that are put to practical use in the cleaning treatment method, but in order to store this as a liquid for a long period of time by processing with a cleaning method using a liquid adsorbent, quantitatively, There are also many safety issues. In addition, in the physical / chemical treatment method using solid adsorbent filling, the trapped iodine is always exposed to the possibility of exchange with other gases, and the adsorbate is easily released when the temperature rises. There are difficulties. Furthermore, in the treatment system using an ion exchanger, the heat resistant temperature of the ion exchanger is up to about 100 ° C., and there is a problem that sufficient performance cannot be exhibited at a temperature higher than this.

  On the other hand, as a method for treating radioactive cesium generated by nuclear fission in a nuclear reactor, an adsorption method using an inorganic ion exchanger or a selective ion exchange resin, a coprecipitation method using a heavy metal and a soluble ferrocyanide or a ferrocyanide salt in combination, A chemical treatment method using a cesium precipitation reagent is known (see Patent Document 4).

  However, all of the above-described processing methods require large-scale equipment such as a circulation pump, a septic tank, and a filling tank containing each adsorbent, and further, a large amount of energy is required to operate them. In addition, as the Fukushima Daiichi nuclear power plant accident in Japan on March 11, 2011, when the power supply was cut off, these facilities would not be able to operate, so contamination with radioactive iodine, radioactive cesium, etc. The risk level of increases. And especially when the power supply is cut off, the removal method for radioactive iodine and radioactive cesium diffused in the surrounding area due to the runaway accident of the reactor falls into a very difficult situation, and the radioactive contamination may be expanded. There is a concern that the situation will not be. Accordingly, there is an urgent need to develop a technique for removing radioactive iodine and radioactive cesium that can cope with such a situation. In addition, it would be extremely useful if an effective removal technique capable of treating radioactive iodine and radioactive cesium together was developed.

Japanese Patent Publication No.62-44239 JP 2008-116280 A JP 2005-37133 A JP-A-4-118596

  Accordingly, an object of the present invention is to solve the problems of the prior art in providing an effective removal technique capable of treating radioactive iodine and radioactive cesium together, and to reduce energy consumption such as electric power easily and at low cost. A new radioactive iodine / radioactive material that is not required, and that can be stably fixed by taking the removed radioactive iodine and radioactive cesium into the solid, and reducing the volume of radioactive waste as required. It is to provide a cesium removal technology. The object of the present invention is a novel hydrophilic resin having a function capable of immobilizing both radioactive iodine and radioactive cesium, which is particularly useful for the above-described technology, and capable of removing these together. It is to provide a composition.

  The above object is achieved by the present invention described below. That is, the present invention provides a treatment for removing both radioactive iodine and radioactive cesium present in the radioactive liquid waste and / or radioactive solids using a hydrophilic resin composition comprising a hydrophilic resin and a ferrocyanide metal compound. A method for removing radioactive iodine and radioactive cesium, wherein the hydrophilic resin has a hydrophilic segment and has a tertiary amino group in the main chain and / or side chain in the structure And at least one selected from the group consisting of a resin, a hydrophilic polyurea resin, and a hydrophilic polyurethane-polyurea resin, and the hydrophilic resin composition contains at least ferrocyan with respect to 100 parts by mass of the hydrophilic resin. Provided is a method for removing radioactive iodine and radioactive cesium, characterized in that the metal halide compound is dispersed at a ratio of 1 to 200 parts by mass.

The following are mentioned as a preferable form of this invention. The hydrophilic segment is a polyethylene oxide segment. The hydrophilic resin is a resin formed by using a polyol having at least one tertiary amino group or a polyamine having at least one tertiary amino group as a raw material. The ferrocyanide metal compound is a compound represented by the following general formula (1).
_{A x M y [Fe (CN} ) 6] (1)
[Wherein, A is any one selected from K, Na, and NH ₄ , M is any one selected from Ca, Mn, Fe, Co, Ni, Cu, and Zn, and x, y Satisfies the formula x + ny = 4 (x is a number from 0 to 3), and n represents the valence of M. ]

  In another aspect of the present invention, there is provided a hydrophilic resin composition having a function capable of fixing both radioactive iodine and radioactive cesium in a liquid and / or a solid material, the hydrophilic resin and a ferrocyanide metal. A hydrophilic segment, wherein the hydrophilic resin is formed using a polyol having at least one tertiary amino group or a polyamine having at least one tertiary amino group as a part of a raw material, , A resin having a tertiary amino group in the molecular chain and insoluble in water and warm water, and at least 1 ferrocyanide compound with respect to 100 parts by mass of the hydrophilic resin. Disclosed is a hydrophilic resin composition for removing radioactive iodine and radioactive cesium, which is dispersed at a ratio of ˜200 parts by mass.

  Furthermore, in another aspect of the present invention, as another embodiment, a hydrophilic resin composition having a function capable of fixing both radioactive iodine and radioactive cesium in a liquid and / or a solid substance, the hydrophilic resin and ferrocyanated And a hydrophilic compound comprising an organic polyisocyanate, a high molecular weight hydrophilic polyol and / or polyamine which is a hydrophilic component, at least one active hydrogen-containing group and at least one tertiary. A hydrophilic polyurethane obtained by reacting a compound having an amino group in the same molecule and having a hydrophilic segment and a tertiary amino group in the main chain and / or side chain in the structure And at least one selected from the group consisting of a resin, a hydrophilic polyurea resin, and a hydrophilic polyurethane-polyurea resin, and less than 100 parts by mass of the hydrophilic resin. Kutomo, ferrocyanide metal compound to provide a hydrophilic resin composition for removing radioactive iodine, radioactive cesium, characterized in that it is dispersed at a ratio of 1 to 200 parts by weight.

The following is mentioned as a preferable form of one of the above-described hydrophilic resin compositions of the present invention. The hydrophilic segment of the hydrophilic resin is a polyethylene oxide segment. The ferrocyanide metal compound is a compound represented by the following general formula (1).
_{A x M y [Fe (CN} ) 6] (1)
[Wherein, A is any one selected from K, Na, and NH ₄ , M is any one selected from Ca, Mn, Fe, Co, Ni, Cu, and Zn, and x, y Satisfies the formula x + ny = 4 (x is a number from 0 to 3), and n represents the valence of M. ]

  According to the present invention, radioactive iodine and radioactive cesium present in waste liquid and solid matter are removed easily and at a low cost, and without the need for an energy source such as electric power. Can be fixed stably by working inside the solid, and the volume of radioactive waste can be reduced if necessary. In addition, a new technology that can remove radioactive iodine and radioactive cesium together is provided. Is done. According to the present invention, in particular, it has a function capable of immobilizing both radioactive iodine and radioactive cesium, and it is feasible to remove them together, and the main component is a resin composition. Accordingly, a novel hydrophilic resin composition capable of reducing the volume of radioactive waste as required is provided. These significant effects of the present invention include organic polyisocyanates, high molecular weight hydrophilic polyols and / or polyamines (hereinafter referred to as “hydrophilic components”), at least one active hydrogen-containing group and at least one third. At least one hydrophilic resin selected from the group consisting of a hydrophilic polyurethane resin obtained by reacting a compound having a secondary amino group in the same molecule, a hydrophilic polyurea resin, and a hydrophilic polyurethane-polyurea resin; This is achieved by a very simple method of utilizing a hydrophilic resin composition obtained by dispersing the slag.

The figure which shows the relationship between the iodine ion density | concentration in aqueous solution, and the immersion time of the film produced with the hydrophilic resin composition of Examples 1-3. The figure which shows the relationship between the cesium ion density | concentration in aqueous solution, and the immersion time of the film produced with the hydrophilic resin composition of Examples 1-3. The figure which shows the relationship between the iodine ion density | concentration in aqueous solution, and the immersion time of the film produced with the non-hydrophilic resin composition of Comparative Examples 1-2. The figure which shows the relationship between the cesium ion density | concentration in aqueous solution, and the immersion time of the film produced with the non-hydrophilic resin composition of Comparative Examples 1-2.

Next, the present invention will be described in more detail with reference to preferred embodiments.
The hydrophilic resin composition of the present invention, which characterizes the removal method of the present invention, comprises a composition obtained by dispersing a ferrocyanide compound typified by bitumen in a hydrophilic resin. It has the hydrophilic segment which makes a structural component a structural unit, and the tertiary amino group containing segment which makes a structural unit the component which has at least 1 tertiary amino group, It is characterized by the above-mentioned. That is, the hydrophilic resin used in the present invention is a tertiary resin having a hydrophilic segment as a structural unit and a component having at least one tertiary amino group as a structural unit in the structure. Any material having an amino group-containing segment may be used. When a chain extender is not used during the synthesis of the hydrophilic resin, these segments are bonded at random by a urethane bond, a urea bond, a urethane-urea bond, or the like. When a chain extender is used during the synthesis of the hydrophilic resin, a short chain that is a residue of the chain extender is present between these bonds in addition to the above bonds.

  “Hydrophilic resin” in the present invention means a resin having a hydrophilic group in its molecule but insoluble in water, hot water, etc., and includes polyvinyl alcohol, polyvinyl pyrrolidone, and polyacrylic. It is distinguished from water-soluble resins such as acids and cellulose derivatives.

  The hydrophilic resin composition of the present invention comprises a hydrophilic resin and a ferrocyanide compound represented by bitumen, and by using this composition, radioactive iodine and radioactive cesium are removed together. The present inventors consider the reason why this is possible as follows. First, the hydrophilic resin used in the present invention exhibits excellent water absorption by the hydrophilic segment, and further, by introducing a tertiary amino group into the main chain and / or side chain in the structure, It is considered that an ionic bond is formed between the ionized radioactive iodine and, as a result, is fixed in the hydrophilic resin.

  However, since the ionic bond as described above is easily dissociated in the presence of moisture, it is considered that radioactive iodine is released from the resin again after a certain period of time. It was expected that it would be difficult to remove the fixed state in a fixed state. However, according to the study by the present inventors, it has been found that in practice, the ion-bound radioactive iodine remains fixed in the resin even after a long time. The reason for this is not clear, but the present inventors consider as follows. That is, in the specific hydrophilic resin used in the present invention, a hydrophobic portion is also present in the molecule, and after an ionic bond is formed between the tertiary amino group in the resin and radioactive iodine, It is speculated that this hydrophobic part may surround the hydrophilic part (hydrophilic segment) and the ion binding part. For these reasons, in the present invention, the use of the hydrophilic resin composition of the present invention including a hydrophilic resin having a specific structure enables radioactive iodine to be immobilized on the resin and to be removed. it is conceivable that.

Furthermore, in the present invention, by using the hydrophilic resin composition of the present invention containing a ferrocyanide metal compound typified by bitumen, it is possible to remove radioactive cesium in addition to the above-described removal of radioactive iodine. This achieved the treatment of radioactive iodine and radioactive cesium together. The ferrocyanide compound used in the present invention is a compound represented by the following general formula (1). Some of these are called bitumen and are widely used as coloring materials, and any of them can be suitably used in the present invention.
_{A x M y [Fe (CN} ) 6] (1)
[Wherein, A is any one selected from K, Na, and NH ₄ , M is any one selected from Ca, Mn, Fe, Co, Ni, Cu, and Zn, and x, y Satisfies the formula x + ny = 4 (x is a number from 0 to 3), and n represents the valence of M. ]

More specific examples of the ferrocyanide compound include compounds represented by the following general formulas (A) and (B) called bitumen, which have been produced for a long time. There are many common names such as Prussian blue, Milori blue and Berlin blue.
MFe [Fe (CN) ₆ ] (A) [However, M = NH ₄ , K, Fe]
MK ₂ [Fe (CN) ₆ ] (B) [However, M = Ni, Co]

  It is already known that the above bitumen can be used to remove radioactive cesium, and is actually used in the event of the Chernobyl nuclear power plant accident. The mechanism of bitumen's removal of radioactive cesium has not yet been fully elucidated, but the following two concepts of “ion exchange” and “adsorption” have been proposed.

  The idea of “ion exchange” is that when ammonium bitumen, which is a kind of bitumen, contacts with cesium ions, the cation and cesium ions in the bitumen are replaced by ion exchange, and radioactive cesium is fixed and can be removed. . On the other hand, “adsorption” is an idea that cesium ions are selectively adsorbed in vacancies of about 0.5 nm intervals possessed by the bitumen crystal and are consequently removed. At present, it is not clear which is correct, but in any case, the removal effect of cesium by bitumen has been demonstrated. The metal ferrocyanide compound represented by bitumen capable of removing such radioactive cesium is dispersed in a hydrophilic resin having a unique structure capable of removing the above-mentioned radioactive iodine. By using the hydrophilic resin composition, the present invention provides a technique capable of removing radioactive iodine and radioactive cesium together.

  The hydrophilic resin composition characterizing the present invention comprises a hydrophilic resin, and the hydrophilic resin comprises a hydrophilic segment having a hydrophilic component as a constituent unit, and at least one tertiary amino group. It has the tertiary amino group containing segment which has the component which has as a structural unit, It is characterized by the above-mentioned. Specific examples include hydrophilic polyurethane resins, hydrophilic polyurea resins, and hydrophilic polyurethanes having a hydrophilic segment and a tertiary amino group in the main chain and / or side chain in the structure. -At least 1 sort (s) chosen from the group which consists of polyurea resin is mentioned.

  Such an organic polyisocyanate, a high molecular weight hydrophilic polyol and / or polyamine which is a hydrophilic component, at least one active hydrogen-containing group and at least one tertiary amino group are the same molecule. It is obtained by reacting with the compound contained therein. That is, the compound used for introducing the hydrophilic segment and the tertiary amino group into the structure of the hydrophilic resin used in the present invention includes at least one active hydrogen-containing group (reactive group) in the molecule. ) And having a tertiary amino group in the molecular chain. Examples of the compound having at least one active hydrogen-containing group include compounds having a reactive group such as an amino group, an epoxy group, a hydroxyl group, a mercapto group, an acid halide group, a carboxyester group, and an acid anhydride group. .

［式（２）中の、Ｒ₁は炭素数２０以下のアルキル基、脂環族基、又は芳香族基（ハロゲン、アルキル基で置換されていてもよい）であり、Ｒ₂及びＲ₃はそれぞれ、−Ｏ−、−ＣＯ−、−ＣＯＯ−、−ＮＨＣＯ−、−Ｓ−、−ＳＯ−、−ＳＯ₂−等で連結されていてもよい低級アルキレン基であり、Ｘ及びＹは、−ＯＨ、−ＣＯＯＨ、−ＮＨ₂、−ＮＨＲ₁（Ｒ₁は上記と同じ定義である）、−ＳＨ等の反応性基であり、Ｘ及びＹは、同一でも異なってもよい。又、Ｘ及びＹは、上記の反応性基に誘導できるエポキシ基、アルコキシ基、酸ハライド基、酸無水物基、又はカルボキシルエステル基でもよい。］ Preferable examples of the tertiary amino group-containing compound having a reactive group as described above include compounds represented by the following general formulas (2) to (4).

[In Formula (2), R ₁ is an alkyl group having 20 or less carbon atoms, an alicyclic group, or an aromatic group (which may be substituted with a halogen or an alkyl group), and R ₂ and R ₃ are each, -O -, - CO -, - COO -, - NHCO -, - S -, - SO -, - SO 2 - is a substituted lower alkylene group which may be coupled with such, X and Y, - OH, —COOH, —NH ₂ , —NHR ₁ (R ₁ has the same definition as above), —SH and the like, and X and Y may be the same or different. X and Y may be an epoxy group, an alkoxy group, an acid halide group, an acid anhydride group, or a carboxyl ester group that can be derived from the above reactive group. ]

［式（３）中の、Ｒ₁、Ｒ₂、Ｒ₃、Ｘ及びＹは、前記式（２）におけるものと同じ定義であるが、但し、２つのＲ₁同士は環状構造を形成するものであってもよい。Ｒ₄は−(ＣＨ₂)_n−、（ｎは０〜２０の整数）である。］

[In formula (3), R ₁ , R ₂ , R ₃ , X and Y have the same definition as in formula (2), provided that two R ₁ form a cyclic structure. It may be. R ₄ is — (CH ₂ ) _n —, where n is an integer of 0-20. ]

（式（４）中の、Ｘ及びＹは、前記式（２）におけるものの定義と同じであり、Ｗは、窒素含有複素環、窒素と酸素含有複素環、又は窒素と硫黄含有複素環を表す。）

(X and Y in the formula (4) are the same as defined in the formula (2), and W represents a nitrogen-containing heterocyclic ring, a nitrogen and oxygen-containing heterocyclic ring, or a nitrogen and sulfur-containing heterocyclic ring. .)

  Specific examples of the compounds represented by the above general formulas (2), (3) and (4) include the following. For example, N, N-dihydroxyethyl-methylamine, N, N-dihydroxyethyl-ethylamine, N, N-dihydroxyethyl-isopropylamine, N, N-dihydroxyethyl-n-butylamine, N, N-dihydroxyethyl-t -Butylamine, methyliminobispropylamine, N, N-dihydroxyethylaniline, N, N-dihydroxyethyl-m-toluidine, N, N-dihydroxyethyl-p-toluidine, N, N-dihydroxyethyl-m-chloroaniline N, N-dihydroxyethylbenzylamine, N, N-dimethyl-N ′, N′-dihydroxyethyl-1,3-diaminopropane, N, N-diethyl-N ′, N′-dihydroxyethyl-1,3 -Diaminopropane, N-hydroxyethyl-piperazine, N N-dihydroxyethyl-piperazine, N-hydroxyethoxyethyl-piperazine, 1,4-bisaminopropyl-piperazine, N-aminopropyl-piperazine, dipicolinic acid, 2,3-diaminopyridine, 2,5-diaminopyridine, 2 , 6-diamino-4-methylpyridine, 2,6-dihydroxypyridine, 2,6-pyridine-dimethanol, 2- (4-pyridyl) -4,6-dihydroxypyrimidine, 2,6-diaminotriazine, 2, 5-diaminotriazole, 2,5-diaminooxazole and the like can be mentioned.

  Also, ethylene oxide adducts and propylene oxide adducts of these tertiary amino compounds can be used in the present invention. Examples of the adduct include compounds represented by the following structural formula. In the following formula, m represents an integer of 1 to 60, and n represents an integer of 1 to 6.

  As the organic polyisocyanate used for synthesizing the hydrophilic resin characterizing the present invention, any known ones in the synthesis of conventional polyurethane resins can be used and are not particularly limited. Preferable examples include 4,4′-diphenylmethane diisocyanate (MDI), hydrogenated MDI, isophorone diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 2,4-tolylene diisocyanate, m It is also possible to use -phenylene diisocyanate, p-phenylene diisocyanate, or the like, or a polyurethane prepolymer obtained by reacting these organic polyisocyanates with a low molecular weight polyol or polyamine so as to be a terminal isocyanate.

  As the hydrophilic component used in the synthesis of the hydrophilic resin characterizing the present invention together with the organic polyisocyanate described above, the hydrophilic component having a hydroxyl group, amino group, carboxyl group and the like having a weight average molecular weight in the range of 400 to 8,000. A compound having is preferred. Examples of the polyol having a hydroxyl group at the end and hydrophilicity include polyethylene glycol, polyethylene glycol / polytetramethylene glycol copolymer polyol, polyethylene glycol / polypropylene glycol copolymer polyol, polyethylene glycol adipate polyol, polyethylene glycol succinate polyol, polyethylene Examples include glycol / polyε-lactone copolymer polyol, polyethylene glycol / polyvalerolactone copolymer polyol, and the like.

  Examples of the polyamine having a terminal amino group and hydrophilicity include polyethylene oxide diamine, polyethylene oxide propylene oxide diamine, polyethylene oxide triamine, and polyethylene oxide propylene oxide triamine. Other examples include ethylene oxide adducts having a carboxyl group or a vinyl group.

  In the present invention, in order to impart water resistance to the hydrophilic resin, it is also possible to use other polyols, polyamines, polycarboxylic acids and the like that do not have a hydrophilic chain together with the hydrophilic component.

  As the chain extender used as necessary in the synthesis of the hydrophilic resin characterizing the present invention, for example, any conventionally known chain extender such as a low-molecular diol or a diamine can be used. Not. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, ethylenediamine, hexamethylenediamine and the like can be mentioned.

  The hydrophilic segment obtained using the above raw material components and the hydrophilic resin having a tertiary amino group in the molecular chain have a weight average molecular weight (in terms of standard polystyrene measured by GPC) of 3,000 to 800, It is preferably in the range of 000. A more preferred weight average molecular weight is in the range of 5,000 to 500,000.

  The content of the tertiary amino group in the hydrophilic resin particularly suitable for use in the method for removing radioactive iodine and radioactive cesium of the present invention is preferably in the range of 0.1 to 50 eq (equivalent) / kg, more preferably 0.5 to 20 eq / kg. If the content of the tertiary amino group is less than 0.1 eq / kg, that is, not more than 1 per 10,000 molecular weight, the desired release of radioactive iodine, which is the intended purpose of the present invention, becomes insufficient. If the content of tertiary amino groups is 50 eq / kg or more, that is, 500 or more per 10,000 molecular weight, the hydrophobicity increases due to the reduction of the hydrophilic portion in the resin, and the water absorption performance becomes inferior. .

  Further, the content of the hydrophilic segment of the hydrophilic resin particularly suitable for the method for removing radioactive iodine and radioactive cesium of the present invention is preferably in the range of 20 to 80% by mass, more preferably in the range of 30 to 70% by mass. is there. If the content of the hydrophilic segment is less than 20% by mass, the water absorption performance is inferior and the removal property of radioactive iodine is lowered, which is not preferable. On the other hand, if it exceeds 80% by mass, the water resistance becomes inferior.

  The hydrophilic resin composition of the present invention suitable for the method for removing radioactive iodine and radioactive cesium of the present invention comprises a ferrocyanide compound represented by bitumen (hereinafter referred to as bitumen) in the hydrophilic resin described above. It is obtained by dispersing. Specifically, it can be produced by putting a bitumen and a dispersion solvent in the above-described hydrophilic resin and performing a dispersion operation with a predetermined disperser. As the disperser used for the dispersion, any disperser that is usually used for pigment dispersion can be used without any problem. For example, paint conditioner (manufactured by Red Devil), ball mill, pearl mill (manufactured by Eirich), sand mill, visco mill, attritor mill, basket mill, wet jet mill (manufactured by Genus), etc. It is preferable to set in view of the above. Further, as the media, glass beads, zirconia beads, alumina beads, magnetic beads, stainless beads, etc. can be used.

  As a dispersion ratio of the hydrophilic resin and the bitumen in the hydrophilic resin composition of the present invention, a blending ratio of 1 to 200 parts by weight of bitumen with respect to 100 parts by weight of the hydrophilic resin is used. If the bitumen is less than 1 part by mass, the removal of radioactive cesium is insufficient, and if it exceeds 200 parts by mass, the mechanical properties of the composition become weak and the water resistance becomes inferior, and the shape can be maintained in radioactively contaminated water. It is not preferable because it disappears.

  In the method for removing radioactive iodine and radioactive cesium of the present invention, it is preferable to use the hydrophilic resin composition of the present invention having the above-described configuration in the following form. That is, a film obtained by applying a solution of the hydrophilic resin composition to a release paper, a release film or the like so that the thickness after drying is 5 to 100 μm, preferably 10 to 50 μm, and drying in a drying furnace. The thing of the shape is mentioned. In this case, it is peeled off from the release paper / film at the time of use, and used as a film for removing radioactive iodine / radiocesium. In addition, a resin solution obtained from the raw materials described above may be applied or impregnated on various base materials. As the base material in this case, metal, glass, wood, fiber, various plastics and the like can be used.

  The hydrophilic resin composition film characterized by the present invention obtained as described above or a sheet coated on various substrates is immersed in a radioactive waste liquid or a waste liquid obtained by decontaminating radioactive solids with water in advance. By doing so, both radioactive iodine and radioactive cesium can be selectively removed. In addition, solid iodine contaminated by radioactivity can be prevented from diffusing radioactive iodine and radioactive cesium by covering with a film or sheet made of the hydrophilic resin composition of the present invention.

  Since the film or sheet made of the hydrophilic resin composition of the present invention does not dissolve in water, it can be easily taken out from the waste liquid after decontamination. In this way, decontamination can be performed easily and at low cost without requiring special equipment or electric power to remove both radioactive iodine and radioactive cesium. Furthermore, if the absorbed water is dried and heated to 100 to 170 ° C., the resin is softened, the volume shrinks, and the effect of reducing the volume of radioactive waste can be expected.

  Next, the present invention will be described in more detail with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples. In the following examples, “part” and “%” are based on mass unless otherwise specified.

[Production Example 1] (Synthesis of tertiary amino group-containing hydrophilic polyurethane resin)
A reaction vessel equipped with a stirrer, thermometer, gas introduction tube and reflux condenser was replaced with nitrogen, 150 parts of polyethylene glycol (molecular weight 2,040), 20 parts of N-methyldiethanolamine, 5 parts of diethylene glycol, 200 parts of methyl ethyl ketone ( Hereinafter, it was dissolved in a mixed solvent of 150 parts of dimethylformamide (hereinafter abbreviated as DMF) and stirred at 60 ° C. well. While stirring, a solution of 74 parts of hydrogenated MDI (4,4′-diphenylmethane diisocyanate; hereinafter abbreviated as hydrogenated MDI) in 112 parts of MEK was gradually added dropwise. After completion of the dropwise addition, the mixture was reacted at 80 ° C. for 6 hours to obtain a hydrophilic resin solution defined in the present invention. This resin solution had a solid content of 35% and a viscosity of 530 dPa · s (25 ° C.). Moreover, the hydrophilic resin film formed from this solution had a breaking strength of 24.5 MPa, a breaking elongation of 450%, and a thermal softening temperature of 115 ° C.

[Production Example 2] (Tertiary amino group-containing hydrophilic polyurea resin synthesis)
In a reaction vessel similar to that used in Production Example 1, 150 parts of polyethylene oxide diamine (“Jeffamine ED” (trade name) manufactured by Huntsman; molecular weight 2,000), 30 parts of methyliminobispropylamine and 1,4- 4 parts of diaminobutane was dissolved in 200 parts of DMF and stirred well at an internal temperature of 20-30 ° C. Then, with stirring, a solution obtained by dissolving 83 parts of hydrogenated MDI in 100 parts of DMF was gradually added dropwise to react. After completion of the dropping, the internal temperature was gradually raised, and when the temperature reached 50 ° C., the mixture was further reacted for 6 hours, and 195 parts of DMF was added to obtain a hydrophilic resin solution defined in the present invention. This resin solution had a solid content of 35% and a viscosity of 230 dPa · s (25 ° C.). Moreover, the hydrophilic resin film formed from this resin solution had a breaking strength of 27.6 MPa, a breaking elongation of 310%, and a thermal softening temperature of 145 ° C.

[Production Example 3] (Synthesis of tertiary amino group-containing hydrophilic polyurethane-polyurea resin)
In the same reaction vessel as used in Production Example 1, 150 parts of polyethylene oxide diamine (“Jeffamine ED” (trade name); molecular weight 2,000, manufactured by Huntsman), N, N-dimethyl-N ′, N ′ -30 parts of dihydroxyethyl-1,3-diaminopropane and 6 parts of triethylene glycol were dissolved in 140 parts of DMF. And the solution which melt | dissolved 70 parts hydrogenation MDI in 200 parts MEK was dripped gradually, stirring well with internal temperature 20-30 degreeC. After completion of the dropwise addition, the mixture was reacted at 80 ° C. for 6 hours, and 135 parts of MEK was added to obtain a hydrophilic resin solution defined in the present invention. This resin solution had a solid content of 35% and a viscosity of 280 dPa · s (25 ° C.). Further, the hydrophilic resin film formed from this resin solution had a breaking strength of 14.7 MPa, a breaking elongation of 450%, and a thermal softening temperature of 107 ° C.

[Production Example 4] (Synthesis of tertiary amino group-free non-hydrophilic polyurethane resin used in Comparative Example)
The same reaction vessel as that used in Production Example 1 was purged with nitrogen, and 150 parts of polybutylene adipate having an average molecular weight of about 2,000 and 15 parts of 1,4-butanediol were dissolved in 250 parts of DMF. And what melt | dissolved 62 parts hydrogenation MDI in 171 parts DMF was dripped gradually, stirring well at 60 degreeC. After completion of the dropwise addition, the mixture was reacted at 80 ° C. for 6 hours to obtain a resin solution used in the comparative example. This resin solution had a solid content of 35% and a viscosity of 3.2 MPa · s (25 ° C.). The non-hydrophilic resin film obtained from this resin solution had a breaking strength of 45 MPa, a breaking elongation of 480%, and a thermal softening temperature of 110 ° C.

[Production Example 5] (Tertiary amino group-containing non-hydrophilic polyurethane resin used in Comparative Example)
A reaction vessel similar to that used in Production Example 1 was replaced with nitrogen, 150 parts of polybutylene adipate having an average molecular weight of about 2,000, 20 parts of N-methyldiethanolamine, 5 parts of diethylene glycol, 200 parts of MEK and 150 parts of Dissolved in a mixed solvent with DMF. And the solution which melt | dissolved 74 parts hydrogenation MDI in 112 parts MEK was dripped gradually, stirring well at 60 degreeC. After completion of the dropwise addition, the mixture was reacted at 80 ° C. for 6 hours to obtain a resin solution used in the comparative example. This resin solution had a solid content of 35% and a viscosity of 510 dPa · s (25 ° C.). The non-hydrophilic resin film formed from this resin solution had a breaking strength of 23.5 MPa, a breaking elongation of 470%, and a thermal softening temperature of 110 ° C.

  The characteristics of the resins obtained in Production Examples 1 to 5 are shown in Table 1. Specifically, the hydrophilicity was evaluated, the weight average molecular weight, and the tertiary amino group content (equivalent) per 1,000 molecular weights.

<Examples 1-3, Comparative Examples 1-2>
Each resin solution obtained in Production Examples 1 to 5 and bitumen (Miroli Blue (color name); manufactured by Dainichi Seika Kogyo Co., Ltd.) were mixed with the high density alumina balls (3.5 g) shown in Table 2. / Ml) for 24 hours with a ball mill. And the content after dispersion | distribution was taken out through the 100-mesh sieve made from a polyester resin, and each liquid resin composition containing a resin solution and a bitumen was obtained.

[Evaluation]
(Production of resin film)
Using the liquid resin compositions of Examples 1 to 3 and Comparative Examples 1 and 2, the resin films were prepared as follows. Specifically, after each of the above resin compositions was applied onto a release paper, the solvent was evaporated by heating and drying at 110 ° C. for 3 minutes to prepare each resin film having a thickness of about 20 μm. Next, each resin film thus obtained was used to evaluate the effect on the removal of iodine ions and cesium ions by the following method.

(Production of iodine solution and cesium solution for evaluation test)
The iodine solution for the evaluation test was prepared by dissolving potassium iodide in ion-exchanged pure water so that the iodine ion concentration was 200 mg / L (200 ppm). Moreover, the cesium solution for an evaluation test was prepared by dissolving cesium chloride in ion-exchanged pure water so that the cesium ion concentration was 200 mg / L (200 ppm). If iodine ions and cesium ions can be removed, naturally, radioactive iodine and radioactive cesium can be removed.

<The evaluation result about the resin composition of Example 1>
20 g of the resin film produced using the hydrophilic resin composition of Example 1 was immersed in a mixed solution of 50 ml of iodine solution and 50 ml of cesium solution prepared for the evaluation test previously (25 ° C.), and every elapsed time. The iodine ion concentration and the cesium ion concentration in the solution were measured by an ion chromatograph (manufactured by Tosoh; IC2001). The measurement results are shown in Table 3. As shown in Table 3, it was confirmed that both the iodine ion concentration and the cesium ion concentration in the solution decreased with each elapsed time. In Table 3, the removal rates of these ions in the solution for each elapsed time are also shown. The results are shown in FIG. 1 and FIG.

<The evaluation result about the resin composition of Example 2>
Except for using 20 g of the resin film prepared with the hydrophilic resin composition of Example 2, as in the case of using the resin film prepared with the hydrophilic resin composition of Example 1, in the solution for each elapsed time. The iodine ion concentration and the cesium ion concentration were measured. The obtained results are shown in Table 4 and FIGS. 1 and 2 as in the case of Example 1 described above.

<The evaluation result about the resin composition of Example 3>
Except for using 20 g of the resin film prepared with the hydrophilic resin composition of Example 3, as in the case of using the resin film prepared with the hydrophilic resin composition of Example 1, in the solution every elapsed time. The iodine ion concentration and the cesium ion concentration were measured. The obtained results are shown in Table 5 and FIGS. 1 and 2 as in the case of Example 1 described above.

<Evaluation result about the resin composition of Comparative Example 1>
Except for using 20 g of the resin film prepared with the non-hydrophilic resin composition of Comparative Example 1, a solution was prepared for each elapsed time in the same manner as with the resin film prepared using the hydrophilic resin composition of Example 1. The iodine ion concentration and the cesium ion concentration were measured. The obtained results are shown in Table 6 and FIGS. 3 and 4 as in the case of Example 1 described above.

<Evaluation result about the resin composition of Comparative Example 2>
Except for using 20 g of the resin film prepared with the non-hydrophilic resin composition of Comparative Example 2, a solution was prepared for each elapsed time in the same manner as with the resin film prepared with the hydrophilic resin composition of Example 1. The iodine ion concentration and the cesium ion concentration were measured. The obtained results are shown in Table 7 and FIGS. 3 and 4 as in the case of Example 1 described above.

  As an application example of the present invention, radioactive iodine and radioactive cesium in radioactive liquid waste and / or radioactive solids can be removed easily and at low cost, and without the need for an energy source such as electric power. By implementing the simultaneous removal method of radioactive iodine and radioactive cesium, it has become possible to easily and economically remove radioactive substances that have recently become a problem in waste liquids and solids. Therefore, its practical value is extremely high. Furthermore, in the technique of the present invention, the removed radioactive iodine and radioactive cesium can be taken in and stably fixed to the hydrophilic resin composition comprising a hydrophilic resin having a specific structure and bitumen, Furthermore, since the main component is a resin composition, it is possible to reduce the volume of radioactive waste as necessary, which can reduce problems with large amounts of radioactive waste generated after the removal of radioactive materials. , Its use is expected.

Claims (8)

Radioactive iodine / radioactive cesium removed by using a hydrophilic resin composition comprising a hydrophilic resin and a metal ferrocyanide together with radioactive iodine and radioactive cesium present in radioactive liquid waste and / or radioactive solids A method for removing
The hydrophilic resin has a hydrophilic segment and a hydrophilic group in the molecule, but is insoluble in water and warm water, and has a main chain and / or side in the structure. Including at least one selected from the group consisting of a hydrophilic polyurethane resin, a hydrophilic polyurea resin, a hydrophilic polyurethane-polyurea resin having a tertiary amino group in the chain; and
Radioiodine / radioactive cesium characterized in that the hydrophilic resin composition comprises at least a metal ferrocyanide compound dispersed in an amount of 1 to 200 parts by mass with respect to 100 parts by mass of the hydrophilic resin. Removal method.   The method for removing radioactive iodine / radioactive cesium according to claim 1, wherein the hydrophilic segment is a polyethylene oxide segment.   3. The resin according to claim 1, wherein the hydrophilic resin is a resin formed using a polyol having at least one tertiary amino group or a polyamine having at least one tertiary amino group as a part of a raw material. To remove radioactive iodine and radioactive cesium. The method for removing radioactive iodine and radioactive cesium according to any one of claims 1 to 3, wherein the metal ferrocyanide compound is a compound represented by the following general formula (1).
_{A x M y [Fe (CN} ) 6] (1)
[Wherein, A is any one selected from K, Na, and NH ₄ , M is any one selected from Ca, Mn, Fe, Co, Ni, Cu, and Zn, and x, y Satisfies the formula x + ny = 4 (x is a number from 0 to 3), and n represents the valence of M. ] A hydrophilic resin composition showing a function capable of fixing both radioactive iodine and radioactive cesium in a liquid and / or solid matter,
A hydrophilic resin and a ferrocyanide metal compound,
In the molecular chain, the hydrophilic resin is formed by using a polyol having at least one tertiary amino group or a polyamine having at least one tertiary amino group as a part of a raw material, A resin having a tertiary amino group, insoluble in water and warm water, and
A hydrophilic resin composition for removing radioactive iodine and radioactive cesium, wherein at least a metal ferrocyanide compound is dispersed in an amount of 1 to 200 parts by mass with respect to 100 parts by mass of the hydrophilic resin. . A hydrophilic resin composition showing a function capable of fixing both radioactive iodine and radioactive cesium in a liquid and / or solid matter,
A hydrophilic resin and a ferrocyanide metal compound,
The hydrophilic resin is an organic polyisocyanate, a high molecular weight hydrophilic polyol and / or polyamine which is a hydrophilic component, at least one active hydrogen-containing group and at least one tertiary amino group in the same molecule. It has a hydrophilic segment obtained by reacting with a compound contained therein, and has a hydrophilic group in its molecule, but is insoluble in water and warm water, and in the structure And having a tertiary amino group in the main chain and / or side chain thereof, at least one selected from the group consisting of a hydrophilic polyurethane resin, a hydrophilic polyurea resin, and a hydrophilic polyurethane-polyurea resin, and
A hydrophilic resin composition for removing radioactive iodine and radioactive cesium, wherein at least a metal ferrocyanide compound is dispersed in an amount of 1 to 200 parts by mass with respect to 100 parts by mass of the hydrophilic resin. .   The hydrophilic resin composition for removing radioactive iodine and radioactive cesium according to claim 5 or 6, wherein the hydrophilic segment of the hydrophilic resin is a polyethylene oxide segment. The hydrophilic resin composition for removing radioactive iodine / radiocesium according to any one of claims 5 to 7, wherein the metal ferrocyanide compound is a compound represented by the following general formula (1).
_{A x M y [Fe (CN} ) 6] (1)
[Wherein, A is any one selected from K, Na, and NH ₄ , M is any one selected from Ca, Mn, Fe, Co, Ni, Cu, and Zn, and x, y Satisfies the formula x + ny = 4 (x is a number from 0 to 3), and n represents the valence of M. ]

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