KR20200064526A - Self-assembled radioactive cesium removal complex, method for producing the same, and method for removing radioactive cesium using the same - Google Patents

Abstract

Disclosed in the present specification are a self-assembled radioactive cesium removal complex, a method for producing the same, and a method for removing radioactive cesium using the same. The self-assembled radioactive cesium removal complex includes a self-assembled chalcogen compound and an ammonium group bound to the chalcogen compound surface.

Description

Self-assembled radioactive cesium removal complex, manufacturing method thereof and radioactive cesium removal method using same {SELF-ASSEMBLED RADIOACTIVE CESIUM REMOVAL COMPLEX, METHOD FOR PRODUCING THE SAME, AND METHOD FOR REMOVING RADIOACTIVE CESIUM USING THE SAME}

The present invention relates to a self-assembled radioactive cesium removal complex, a method for manufacturing the same, and a radioactive cesium removal method using the same. More specifically, the present invention is a self-assembled chalcogenide compound; And an ammonium group bound to the surface of the chalcogen compound. It relates to a self-assembled radioactive cesium removal complex, a method of manufacturing the same, and a radioactive cesium removal method using the same.

Cs-137, one of the radioactive polluted nuclides, has a half-life of 30 years, and is a major effluent in the event of a nuclear accident, and requires adsorption technology to decontaminate quickly and efficiently.

Cs-137 and other radioactive wastes were present in the contaminated water from the Fukushima nuclear power plant accident in the northeastern region of Japan in 2011. At the time, the existing zeolite decontamination technology was used, but secondary contamination due to low removal efficiency and high concentration treatment Since additional problems such as water generation have occurred, the need for new technology development is emerging.

WO2017-200358 A1 KR 10-1429560 B1 US 9455054 B2 US 2015/0343436A1

Journal of Materials Chemistry 2008, 18, 3628-3632 Bioresource Tehcnology, 2016, 218, 391-398 Bioresource Technology, 2016, 218, 294-300 Dalton Transaction, 2013, 42, 16049-16055 Sheha, R. R.; Metwally, E., Equilibrium Isotherm Modeling of Cesium Adsorption onto Magnetic Materials. J Hazard Mater 2007, 143, 354-361.

An object of the present invention is a self-assembled chalcogen compound; And an ammonium group bound to the surface of the chalcogen compound; to provide a self-assembled radioactive cesium removal complex capable of efficiently removing cesium even at a low initial concentration, a method for manufacturing the same, and a method for removing radioactive cesium using the same .

In an exemplary embodiment of the present invention, a self-assembled chalcogen compound; And an ammonium group attached to the surface of the chalcogen compound.

In an exemplary embodiment of the present invention, in the method for preparing the self-assembled radioactive cesium removal complex described above, synthesizing a single precursor comprising chalcogen ions and ammonium ions; Dispersing the single precursor in an organic solvent to produce a gel by self-assembly reaction; And drying the gel with supercritical carbon dioxide (CO ₂ ); provides a method for producing a self-assembled radioactive cesium removal complex comprising a.

In an exemplary embodiment of the present invention, using the above-described self-assembled radioactive cesium removal complex, removing radioactive cesium ions; provides a method for removing radioactive cesium.

The self-assembled radioactive cesium removal complex according to the present invention includes a self-assembled chalcogen compound and an ammonium group bound thereto, where radioactive cesium ions are substituted for the ammonium group or physically adsorbed in the complex, effectively removing cesium ions can do.

In addition, the method of manufacturing a self-assembled radioactive cesium removal complex according to the present invention uses a ammonium ion which is a general-purpose material rather than an expensive transition metal, and solidifies the chalcogen compound through self-assembly, thereby making it simple and economical A radioactive cesium removal complex can be prepared.

1 is a schematic diagram showing a method for preparing a self-assembled radioactive cesium removal complex according to the present invention, thiostannate (Thiostannates) ([Sn ₂ S ₆ ] ^4- ) and each organic ligand (Ligand) ammonium salt ( It shows the preparation method of forming the TAC (Tin Ammonium Chalcogel) materials through the Sol-Gel reaction with Ammonium Salts.
Figure 2 is XRD data showing the amorphous characteristics of the TAC materials as a whole, the black graph is a supercritical dried Aerogel material according to an embodiment, and the red graph is a Xerogel material with a porous structure minimized by drying at normal atmospheric pressure.
Figure 3 is a surface SEM analysis of the TAC-1, TAC-2, TAC-3, and TAC-4 prepared in the present invention (supercritical carbon treated).
4 is a nitrogen volume isotherm analysis data of TAC-3 according to an embodiment of the present invention.
5 is XPS analysis data of a supercritical carbon-treated TAC-3 material after a sol-gel process reaction in an embodiment of the present invention.
6 is a comparative example of the present invention, without going through a supercritical carbon dioxide drying process, is a photograph of TAC samples dried by a general reduced pressure filter treatment.
7 is a graph showing the amount of cesium removal according to the size and chemical hardness of ammonium groups, for TAC-1, TAC-2, TAC-3, and TAC-4 prepared in Examples of the present invention. .

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention disclosed in the text are exemplified for illustrative purposes only, and the embodiments of the present invention may be implemented in various forms and should not be interpreted as being limited to the embodiments described in the text. .

The present invention can be variously modified and can have various forms, and the embodiments are not intended to limit the present invention to a specific disclosed form, and all modifications, equivalents, or substitutes included in the spirit and scope of the present invention It should be understood to include.

In the present specification, when a part “includes” a certain component, it means that the component may further include other components, rather than excluding other components, unless otherwise specified.

Self-assembled radioactive cesium removal complex

In exemplary embodiments of the present invention, a self-assembled chalcogen compound; And an ammonium group attached to the surface of the chalcogen compound.

[Sn ₂ S ₆ ] Some chalcogenide structures (ions), including ^4- , are materials of various porous structures with unique properties and functionality due to the property of maintaining their own three-dimensional or two-dimensional local structure in the organic solution state (Fig. 1, [Sn ₂ S ₆ ] ^4- structure). The chalcogen structures, when dissolved in solution, can form various porous structures of a combination of chalcogen-transition metals when combined with cation-type transition metal ions, due to their anionic form. However, in order to be connected with practical applications, it is necessary to develop a technology capable of synthesizing a chalcogen porous structure with a versatile material, rather than transition metals that are difficult to obtain or expensive.

Accordingly, the present inventors did not perform the metathesis method using the conventional positive-anion binding reaction, but instead of [Sn ₂ S ₆ ] ^4- thiolysis reaction of a single sample (single precursor) with a local structure. A self-assembled radioactive cesium removal composite was developed.

In addition, while being economical and highly versatile, it is possible to modify the ammonium functional group having a high Cs ⁺ ion-substitution function to the surface, thereby reducing the concentration of contaminants, especially radioactive cesium, with high efficiency and speed. Specifically, based on the Hard Soft Acid Base Theory, it is expected that ammonium groups having similar chemical hardness in aqueous solution can adsorb (or replace, exchange) Cs ions very efficiently.

In exemplary embodiments, the self-assembled radioactive cesium removal composite may be a porous airgel.

In exemplary embodiments, the self-assembled radioactive cesium removal complex may be a three-dimensional tetrahedral coordination structure. The self-assembled radioactive cesium removal complex according to the present invention retains the three-dimensional tetrahedral coordination structure even after chalcogen ions are bonded. Specifically, this provides stability to the binding power to sulfur and tin, which are the skeletons necessary for maintaining the functionality and the ammonia having cesium ion adsorption function, so that when the cesium ion is controlled, the basic skeletal structure collapses to prevent secondary contamination of polluted water. do

In example embodiments, the self-assembled radioactive cesium removal complex may be an amorphous structure. Since the amorphous structure has a porous structure of various sizes compared to the crystalline structure, the dispersion degree in the aqueous solution is better, and the surface tension generated when the aqueous solution adheres to the surface of the porous structure is small, so that the adsorbents in the center of the general crystalline micropore suffer The problem of destruction of the porous structure by back pressure is much less.

In exemplary embodiments, the self-assembled radioactive cesium removal composite may have a BET (Brunauer-Emmett-Teller) surface area of 30 to 300 m ² /g, for example, the BET surface area of 50 m ² / g or more, 100 m ² /g or more, or 150 m ² /g or more, and 280 m ² /g or less, 260 m ² /g or less, or 240 m ² /g or less, preferably 223 to 239 m ² /g.

The standard specific surface area is usually expressed in terms of area per weight, which is a value under which TAC materials are underestimated than those made of relatively light atoms such as carbon, polymer, or oxide. Specifically, since the specific surface area value that positively affects the reactivity of the adsorbent is usually expressed as the surface area possessed per weight of the material, even the same 100 m ² /g of the composite according to the present invention compared to activated carbon or polymer materials The specific surface area can be much more responsive.

When the BET surface area is less than 30 m ² /g, it may be difficult to efficiently remove cesium, and to prepare a composite having a surface area of more than 300 m ² /g due to the heavy properties of chalcogen materials constituting the main axis of the porous structure Is difficult.

In exemplary embodiments, the self-assembled radioactive cesium removal composite may have a pore volume of 0.5 to 3 cm ³ /g, for example, the pore volume of 1.1 cm ³ /g or more, 1.15 cm ³ /g It may be greater than or equal to, 2.7 cm ³ /g or less, 2.5 cm ³ /g or less, or 2.3 cm ³ /g or less, and preferably 1.29 to 1.03 cm ³ /g. When the porous volume has the above range, there is sufficient space for the cesium ions to actively move in the complex, which is preferable for cesium ion removal. When the pore volume is less than 0.5 cm ³ /g, the space for actively moving cesium ions in the composite is reduced, so the efficiency of cesium ion removal may be reduced.

In exemplary embodiments, the self-assembled radioactive cesium removal composite may include a pore size of 50 nm or more and a macropore of 30% or more compared to the total surface area, for example, 35% or more, 40 % Or more, 43% or more, and preferably 46% or more. Accordingly, there is sufficient space for cesium ions to be physically adsorbed.

In exemplary embodiments, the self-assembled chalcogen compound is [Sn ₂ S ₆ ] ^4- , [SnS ₄ ] ^4- , [Sn ₄ S ₁₀ ] ^4- , [GeS ₄ ] ^4- , [Ge ₂ S ₆ ] ^4- , and one or more chalcogen ions selected from the group consisting of [Ge ₄ S ₁₀ ] ^4- may be self-assembled.

In exemplary embodiments, the ammonium group may be at least one selected from the group consisting of tetramethylammonium group, dimethylammonium group, methylammonium group, and ammonium group, preferably It may be a methylammonium (methylammonium) group.

Manufacturing method of self-assembled radioactive cesium removal complex

In exemplary embodiments of the present invention, a method for preparing a self-assembled radioactive cesium removal complex described above, comprising: synthesizing a single precursor comprising chalcogen ions and ammonium ions; Dispersing the single precursor in an organic solvent to produce a gel by self-assembly reaction; And drying the gel with supercritical carbon dioxide (CO ₂ ); provides a method for producing a self-assembled radioactive cesium removal complex comprising a.

Referring to Figure 1, the self-assembly method for producing a self-assembled radioactive cesium removal complex according to the present invention is not a metathesis method using a conventional positive-anion binding reaction [Sn ₂ S ₆ ] ^4- local It has a structure, and relates to a method for synthesizing the first organic-inorganic hybrid chalcogen porous structure material by a self-assembly method through a thiolysis reaction of a single sample (single precursor) containing an ammonium group.

In addition, unlike oxide-based materials that have excellent stability but little possibility of surface modification, the surface can be modified with an ammonium group by a simple substitution process in a solution in an amorphous structure, and a single sample without a complex process ( Complex formation is possible with a single precursor).

In addition, the manufacturing method can maintain the porous structure of the gel and maximize the surface area by drying the self-assembled chalcogen compound containing ammonium groups synthesized in a gel form using carbon dioxide in a supercritical state.

In example embodiments, synthesizing the single precursor comprises: synthesizing a first precursor comprising a chalcogen ion; And reacting an ammonium salt with the first precursor, thereby synthesizing a second precursor comprising a chalcogen ion and an ammonium group. The first precursor synthesis and the second precursor synthesis may each be performed on an aqueous solution. .

In one embodiment, in the step of synthesizing the second precursor, the ammonium salt is tetramethylammonium chloride (TMACl) (97%, Alfa Aesar), trimethylammonium chloride (TriMACl) (98%, Sigma -Aldrich), dimethylammonium chloride (DMACl) (98+%, Alfa Aesar), methylammonium chloride (MACl) (EMD Millipore), and ammonium chloride (ACl) (Extra Pure GRADE, DUKSAN) may be one or more selected from the group consisting of.

In one embodiment, in the step of dispersing the single precursor in an organic solvent to generate a gel by a self-assembly reaction, the organic solvent may be N-methylformamide (NMF), but is not limited thereto.

In exemplary embodiments, after the step of obtaining the gel, performing a solvent substitution on the gel to remove impurities; may further include, the solvent may be alcohol, such as ethanol, but is not limited thereto. Does not. The solvent replacement may be a preparation step for maximizing the porous structure during supercritical drying by substituting with ethanol (Ethanol) in water having a high surface tension.

How to remove radioactive cesium

In exemplary embodiments of the present invention, using the aforementioned self-assembled radioactive cesium removal complex, removing radioactive cesium ions; provides a method for removing radioactive cesium.

In exemplary embodiments, the step of removing the radioactive cesium ion may be performed in an aqueous solution.

In exemplary embodiments, the radioactive cesium removal method may exhibit a removal efficiency of 50% or more when the initial concentration is 100 ppm or less.

The present invention is explained in more detail through the following implementation. However, the examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

Example

Preparation of self-assembled radioactive cesium removal complex

< Calcogen Synthesis of first precursor containing ions>

A Na ₄ Sn ₂ S _{6 ·} 14H ₂ O precursor that provides a [Sn ₂ S ₆ ] ^4- structure on the aqueous solution was used. The Na ₄ Sn ₂ S _{6 ·} 14H ₂ O precursor production method is as follows. The aqueous solution in which Na ₂ S9H ₂ O was dissolved was stirred and reacted with SnCl ₄ 5H ₂ O. Both solutions were stirred at a rate of 5 ml/min or less to prevent rapid pH changes. The resulting powdered solid was reacted through an additional heat treatment at 65° C. along with the aqueous solution state. Thereafter, the first precursor material Na ₄ Sn ₂ S _6· 14H ₂ O was synthesized through pressure filtration and drying.

< Calcogen Ionic and Ammonium group Synthesis of Second Precursor Including>

_{Na 4 Sn 2 S 6 · 14H} 2 O precursor and tetramethylammonium chloride (tetramethylammonium Chloride (TMACl) (97 %, Alfa Aesar), ammonium chloride (dimethylammonium Chloride) (DMACl) ( 98 +%, Alfa Aesar), methyl Ammonium-chalcogenide second precursor for making organic-inorganic hybrid gels by reacting ammonium chloride (MACl) (EMD Millipore), and ammonium chloride (ACl) (Extra Pure GRADE, DUKSAN) The Na ₄ Sn ₂ S _{6 ·} 14H ₂ O precursor and the ammonium substances were stirred in an aqueous solution at room temperature, and methanol was then washed in a large amount using a solution and a centrifuge at 8000 RPM. The separated ammonium-Na ₄ Sn ₂ S _6· 14H ₂ O secondary precursor material was dried.

< Gelation And solvent replacement>

The second precursor material, ammonium-Na ₄ Sn ₂ S _{6 ·} 14H ₂ O, was ultrasonically dispersed in an N-methylformamide (NMF) solution and solidified through a gelation reaction naturally at room temperature. After the solidification reaction was completed over 5-7 days, impurities were removed through substitution for 7 days with an ethanol solvent.

< Supercritical Dry with carbon>

The alcohol-containing gel was dried through a supercritical dryer. Porous structure aerogel combined with tin-sulfur-ammonium that maximizes the surface area through drying process while minimizing surface tension through supercritical carbon dioxide (over 75 atm, over 45 degrees) (Tin Ammonium Chalcogel, TAC) Was synthesized. TAC-1 to TAC-4 were named according to the type of ammonium attached to the surface. (1 = tetramethylammonium, 2 = dimethylammonium, 3 = methylammonium, 4 = ammonium)

In addition, as a comparative example, without drying the supercritical carbon, and prepared in the same manner as in Example, instead of supercritical carbon treatment, a dried Xerogel composite was prepared under general reduced pressure filter conditions.

Test example

<Self-assembled radioactive cesium removal complex observation>

Referring to FIG. 1, TAC-n materials have sulfur (S ^2- ) as a linkage to each coordination site, centered on Sn ^{4 +} having tetrahedral coordination, and are connected to other annotations. It has the structure of a chain. In the case of TAC-4, which has the lowest acidity in ammonium modified on the surface, a partial variation of the structure of [Sn ₂ S ₆ ] ^4- , which has low stability under low pH conditions, was found. Through this, the present invention is expected to be the first case of the chalcogen porous structure that can control the coordination and oxidation state of tin, which is the center of the inorganic sulfur structure through binding with an organic material.

2 and 3, XRD analysis and electron microscopy analysis of the TAC-1, TAC-2, TAC-3, and TAC-4 prepared in the above Examples were performed, and through this, the amorphous structure had a porous structure. I confirmed the fact.

Figure 3 is a surface SEM analysis of the TAC-1, TAC-2, TAC-3, and TAC-4 prepared in Examples of the present invention, referring to this, TAC-1, TAC- prepared in the above Example It can be seen that 2, TAC-3, and TAC-4 have an advanced porous structure with a high surface area (BET surface area 223-239 m ² /g). In addition, it can be seen that cesium ions have a wide pore volume (1.29-2.03 cm ³ /g) that can be actively moved in a solid material.

By calculating the Pore size distribution calculation value through the nitrogen volume isotherm analysis result of FIG. 4, it was confirmed that it contained a large amount of large pores (Macropore) of 50 nm or more in a distribution of about 46%. Specifically, it shows that most adsorption and desorption occurs at 0.8-1.0 relative pressure, and through this, the pore size constituting the porous structure of the TAC-3 material is composed of macropores of 50 nm or more. It can be seen that it is. In addition, since there was little hysteresis between the adsorption and desorption curves, dispersion of the aqueous solution and cesium ions proceeded smoothly without percolation within the porous structure.

FIG. 5 is XPS analysis data of a TAC-3 material after a sol-gel process reaction and supercritical carbon treatment in an embodiment of the present invention. Referring to this, the local structure of the chalcogen structure included in the precursor It can be confirmed that the Tetrarahedral Coordination is maintained.

6 is a comparative example of the present invention, without going through a supercritical carbon dioxide drying process, separated from the solution by a general pressure-reducing filter treatment, and naturally dried for 30 minutes, and vacuum dried for 8 hours to obtain a TAC-1 Xerogel sample. This is a photograph taken, and referring to this, it can be confirmed that the samples that have undergone vacuum or normal pressure drying rather than supercritical drying have a broken porous structure and have a low surface area.

<Radioactivity Cesium ion removal Experiment>

ppm unit test result

The synthesized TAC materials were subjected to a cesium ion performance reaction through agitation on 250 rpm while exposed to an aqueous solution of a radioactive isotope in the aqueous solution. After the reaction, the TAC materials were separated from the aqueous solution and the stirred solution was analyzed for the Cs ion concentration remaining through ICP. Ion adsorption performance was analyzed by changing the initial ion concentration and the stirred ion concentration, and the results are shown in Table 1 below.

Referring to Table 1 below, it can be seen that TAC-n (n = 1-4) materials have the ability to efficiently control cesium ions in an aqueous solution state through cesium ion adsorption experiments. Specifically, Table 1 below is a table briefly comparing cesium adsorption performance of representative comparative materials and TAC materials showing excellent cesium adsorption performance.

In particular, it was confirmed that TAC-3 has an adsorption concentration at 158.7 mg/g based on an initial concentration of 100 ppm or less, and has the ability to efficiently adsorb target Cs ions within a short time of 20 minutes. Previously, Prussian Blue-based adsorption materials showed high efficiency only at high initial concentrations (Iron ferrite, PSMGPB, PB NP), while TAC substances were found at concentrations closer to the actual Cs radioactive contaminant standards. (Less than 100 ppm).

Qe Kd Ci t mg/g mmol/g mL/g ppm H (hour) GO-membrane @ CaF ₂ ^a 148 - - 87 32 PB NP ^b 127.7 - 1.00*10 ¹ 13300 6 PAN-KNiCl ^c 110.3 - 1.46*10 ⁵ 20-240 24 Iron ferrite ^d 111.7 - 8.15*10 ² 133-13300 24 PSMGPB ^e 213.9 - 5.0*10 ⁴ 177300 24 TAC-1 24.1 0.18 2.59*10 ² 100 0.3 TAC-2 104.1 0.78 1.12*10 ³ 100 0.3 TAC-3 158.7 1.19 2.10X10 ³ 100 0.3 TAC-4 119.8 0.90 1.43*10 ³ 100 0.3 Q _e : Cesium removal capacity at equilibrium state. K _d : distribution coefficient. C _i : Initial concentration
^a CaF ₂ supported by graphene oxide membrane ( Colloids and Surfaces A: Physicochemical and Engineering Aspects 2018, 539 , 416-423). ^b Prussian blue nanoparticles ( Dalt . Trans. 2013, 42 , 16049-16055). ^c PAN-based potassium nickel hexacyanoferrate (II) composite spheres ( Radioanal. Nucl . Ch . 2013, 298 , 167-177). ^d Magnetic iron ferrite material ( J. Hazard. Mater. 2007, 143 , 354-361). ^e Pectin-stablized magnetic graphene oxide Prussian blue nanocomposites ( Bioresource Technol . 2016, 216 , 391-398).

Referring to Table 1 and FIG. 7, the TAC samples through the bath adsorption experiment have a smaller ammonium size, and a chemical hardness on the surface is a material having an intermediate property in softness and hardness. Cesium ion adsorption performance was excellent. Methylammonium (MA) belongs to a smaller size and has intermediate chemical hardness, so the ion exchange reaction with cesium ions is very efficient on the TAC-3 surface with MA. I guess it happens.

Claims (15)

Self-assembled chalcogen compounds; And an ammonium group bound to the surface of the chalcogen compound. According to claim 1,
The self-assembled radioactive cesium removal complex, characterized in that the porous airgel, self-assembled radioactive cesium removal complex. According to claim 1,
The self-assembled radioactive cesium removal complex is characterized in that it has a three-dimensional tetrahedral coordination structure, a self-assembled radioactive cesium removal complex. According to claim 1,
The self-assembled radioactive cesium removal complex, characterized in that the amorphous structure, self-assembled radioactive cesium removal complex. According to claim 1,
The self-assembled radioactive cesium removal complex is characterized in that it has a BET (Brunauer-Emmett-Teller) surface area of 30 to 300 m ² /g, a self-assembled radioactive cesium removal complex. According to claim 1,
The self-assembled radioactive cesium removal complex is characterized in that it has a porous volume of 0.5 to 3 cm ³ /g, self-assembled radioactive cesium removal complex. According to claim 1,
The self-assembled radioactive cesium removal complex is characterized in that it comprises a pore size (pore size) of 50 nm or more macropores (macropore) 30% or more based on the total surface area, self-assembled radioactive cesium removal complex. According to claim 1,
The self-assembled chalcogen compound [Sn ₂ S ₆ ] ^4- , [SnS ₄ ] ^4- , [Sn ₄ S ₁₀ ] ^4- , [GeS ₄ ] ^4- , [Ge ₂ S ₆ ] ^4- , and [Ge ₄ S ₁₀ ] Self-assembled radioactive cesium removal complex, characterized in that one or more chalcogen ions selected from the group consisting of ^4- are self-assembled. According to claim 1,
The ammonium group is characterized in that at least one selected from the group consisting of tetramethylammonium (tetramethylammonium), dimethylammonium (dimethylammonium) group, methylammonium (methylammonium) group, and ammonium (ammonium) group, for self-assembling radioactive cesium removal Complex. A method for producing a self-assembled radioactive cesium removal complex according to any one of claims 1 to 9,
Synthesizing a single precursor comprising chalcogen ions and ammonium ions;
Dispersing the single precursor in an organic solvent to produce a gel by self-assembly reaction; And
Drying the gel with supercritical carbon dioxide (CO ₂ ); A method for producing a self-assembled radioactive cesium removal complex comprising a. The method of claim 10,
Synthesizing the single precursor,
Synthesizing a first precursor comprising a chalcogen ion; And
Reacting an ammonium salt to the first precursor, the step of synthesizing a second precursor comprising a chalcogenide ion and an ammonium group; characterized in that it comprises, self-assembly method for producing a radioactive cesium removal complex. The method of claim 10,
After the step of obtaining the gel,
And removing impurities by performing solvent substitution on the gel, further comprising a method for preparing a self-assembled radioactive cesium removal complex. A method for removing radioactive cesium, comprising the step of removing radioactive cesium ions using the self-assembled radioactive cesium removal complex according to any one of claims 1 to 9. The method of claim 13,
The step of removing the radioactive cesium ions is characterized in that made in an aqueous solution, the radioactive cesium removal method. The method of claim 13,
The radioactive cesium removal method is characterized in that it exhibits a removal efficiency of 50% or more when the initial concentration is 100 ppm or less, the radioactive cesium removal method.

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