KR101716570B1 - Preparation method of carbon nanotube adsorbent with metal ferrocyanide having a selective adsorption property to cesium or strontium, adsorbent prepared by the method, and seperation method of cesium or strontium using the adsorbent - Google Patents

Abstract

The present invention relates to a method for producing a carbon nanotube in which ferrocyanide metal is immobilized and a ferrocyanide metal is immobilized with a magnetite, and a cesium or strontium adsorbent.
More specifically, carbon nanotubes are reacted with an acid solution to oxidize the surface, reacted with EDA and DCC to introduce an amine group on the surface, react with a divalent metal-containing compound, and react with a ferrocene-containing compound, The present invention also relates to a method for producing the fixed carbon nanotube. Also, the present invention relates to a method for producing carbon nanotubes by reacting carbon nanotubes with an acid solution to oxidize the surface, reacting the carbon nanotubes with divalent and trivalent iron ions to fix the magnetite on the surface, And a method for producing a carbon nanotube into which a ferrocyanide metal is introduced by reacting it with a divalent metal-containing compound.
The adsorbent containing carbon nanotubes to which the ferrocyanide metal is immobilized and the magnetite is immobilized and the ferrocyanide metal is introduced exhibits a selective adsorption ability to cesium or strontium in the radionuclide.

Description

A method of preparing a carbon nanotube adsorbent having a ferrocyanide metal fixed thereon with selective adsorption to cesium or strontium, an adsorbent prepared therefrom, and a method of separating cesium or strontium using the adsorbent. [0002] The preparation method of carbon nanotube adsorbent with metal ferrocyanide adsorbent prepared by the method, and seperation method of cesium or strontium using the adsorbent}

The present invention relates to a process for producing a carbon nanotube adsorbent having a ferrocyanation metal fixed thereon with selective adsorption to cesium or strontium, an adsorbent prepared therefrom and a method for separating cesium or strontium using the adsorbent.

A fission product is a nuclide produced by fission and is abbreviated FP (Fission Products). The most problematic nuclear power or nuclear fission products, etc. that road accidents are the half-life of cesium-137 (half-life of 30.2 years) and strontium-90 (half-life 29 years), and the cesium ions in the liquid phase, respectively +1 (Cs ⁺⁾ and +2 Is present as a strontium ion (Sr ²⁺ ).

Wastes contaminated with radionuclides have been generated by nuclear accidents in Fukushima recently. In particular, the main nuclides of radionuclides contaminated with cooling water and soil are known as cesium and strontium, and cooling water wastes containing such radioactive materials are in the sea water. The concentration of sodium chloride (NaCl) ions in seawater is higher than that of cesium or strontium ion by several thousands to several tens of thousand times. Therefore, a special technique capable of selectively separating cesium or strontium present in conjunction with a high concentration salt is required. In general, separation techniques such as an evaporation method, a membrane filtration method, and an ion exchange method are used. However, since this separation technique is difficult to selectively separate cesium or strontium, many adsorbents such as silico-titanate and ferrocyanic copper, which have a very high selective separation factor of cesium and strontium, are used .

The ferrocyanide metal adsorbent, which has been mainly researched until now, is fixed to a support such as zeolite, silica, etc. and used as a particle in an adsorption tower. For use in a column, the size of the adsorbent should be at least several tens of micrometers due to the liquid permeability. In general, it is known that when the size of the adsorbent is small, the resistance of the pore diffusional mass transfer is reduced, the adsorption reaction rate is accelerated, and the adsorption capacity is increased due to the increase of the adsorption reaction area. On the other hand, if the size of the adsorbent is small, solid-liquid separation is difficult, and water can not be permeated, making it difficult to use as an adsorption tower. Accordingly, the present inventors have completed the present invention by developing an adsorbent which is easy to carry out solid-liquid separation while keeping the size of the adsorbent small and maintaining the excellent characteristics of reaction speed and adsorption capacity.

It is an object of the present invention to provide a method for producing carbon nanotubes to which ferrocyanide metal is immobilized with improved cesium or strontium adsorption ability.

Another object of the present invention is to provide a cesium or strontium adsorbent containing carbon nanotubes to which ferrocyanide metal is immobilized, the cesium or strontium adsorption ability being improved.

It is still another object of the present invention to provide a method for producing carbon nanotubes in which magnetite is fixed and ferrocyanide metal is introduced, which exhibits enhanced cesium or strontium adsorption ability and exhibits magnetism.

Another object of the present invention is to provide a cesium or strontium adsorbent containing carbon nanotubes to which a magnetite is fixed and a ferrocyanide metal is introduced, which exhibits enhanced cesium or strontium adsorption ability and exhibits magnetism.

Still another object of the present invention is to provide a filter for removing cesium or strontium having the cesium or strontium adsorbent, and a method for treating a radioactive solution using the filter.

It is still another object of the present invention to provide a method for separating cesium or strontium using a cesium or strontium adsorbent containing carbon nanotubes to which the magnetite is fixed and a ferrocyanide metal is introduced.

According to a first aspect of the present invention, there is provided a process for producing a carbon nanotube, comprising the steps of: (1) obtaining carbon nanotubes surface-oxidized by reacting carbon nanotubes with an acid solution; Reacting the surface-oxidized carbon nanotube with ethylenediamine (EDA) and n, n-dicyclohexylcarbodiimide (DCC) to obtain an amine group-introduced carbon nanotube (Step 2); The carbon nanotubes into which amine groups have been introduced on the surface are reacted with a divalent metal-containing compound selected from the group consisting of Cu ²⁺ , Ni ²⁺ , Zn ²⁺ , Fe ²⁺ and Co ²⁺ at a concentration of 0.1 to 1 M To obtain a carbon nanotube into which a divalent metal is introduced (step 3); And reacting the bivalent metal-introduced carbon nanotube with a 0.1-1 M concentration ferrocyanide-containing compound to obtain a carbon nanotube fixed with ferrocyanide metal (Step 4). A method for producing carbon nanotubes is provided.

A second aspect of the present invention provides a cesium or strontium adsorbent produced by the method according to the first aspect, wherein the cerium or strontium adsorbent contains carbon nanotubes whose surface is fixed with metal ferrocyanide.

A third aspect of the present invention is a method for producing carbon nanotubes, comprising the steps of: (1) obtaining carbon nanotubes surface-oxidized by reacting carbon nanotubes with an acid solution; Reacting the surface-oxidized carbon nanotube with Fe ²⁺ and a Fe ³⁺ metal-containing compound under an alkaline condition to obtain a carbon nanotube having a magnetite (Fe ₃ O ₄ ) fixed on its surface (Step 2); And a carbon nanotube on which the magnetite is immobilized on the surface is composed of a ferrocyan-containing compound having a concentration of 0.05 to 0.5 M and a ferrocyanide-containing compound having a concentration of 0.05 to 0.5 M of Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Fe ²⁺ and Co ²⁺ And a step (3) of reacting the ferrocyanide metal with the bivalent metal-containing compound selected from the group consisting of the ferrocyanide metal and the ferrocyanide metal to obtain the carbon nanotube into which the ferrocyanide metal is introduced And a manufacturing method thereof.

A fourth aspect of the present invention provides a cesium or strontium adsorbent produced by the method according to the third aspect and containing carbon nanotubes to which a magnetite is fixed and a ferrocyanation metal is introduced.

A fifth aspect of the present invention provides a cesium or strontium removal filter having a cesium or strontium adsorbent according to the second or fourth aspect.

A sixth aspect of the present invention provides a method for producing purified water comprising passing contaminated water through a cesium or strontium removal filter according to the fifth aspect.

A seventh aspect of the present invention provides a radioactive solution treatment method comprising the step of passing a solution containing a radioactive waste liquid or a radionuclide through a cesium or strontium removal filter according to the fifth aspect to remove radioactive cesium or strontium .

An eighth aspect of the present invention provides a method for producing a cesium or strontium-containing adsorbent comprising the steps of: (1) obtaining a cesium or strontium adsorbent by contacting a cesium or strontium adsorbent of the fourth aspect with a cesium or strontium containing solution; And a step of passing the solution containing the cesium or strontium adsorbed adsorbent through a channel to which a magnetic field is applied to perform solid-liquid separation (step 2).

Hereinafter, the present invention will be described in detail.

The insoluble ferrocyanide metal having the property of selectively adsorbing only radioactive nuclear species is difficult to treat as a fine particle, and there is a limit in application to a fixed layer such as a column due to its weak mechanical strength. Accordingly, methods for fixing ferrocyanide metal on a support such as zeolite, silica, etc. have been proposed. However, these methods have a relatively low specific surface area and adsorption efficiency of the adsorbent, and development of new supports is required.

Carbon nanotubes (CNTs) can be applied as supports and have a large specific surface area and pore volume. By introducing various functional groups on the surface of CNTs by chemical methods, the reactivity between CNTs and molecules can be increased .

The present inventors have found a method for fixing ferrocyanide metal on carbon nanotubes in order to provide a ferrocyanide metal-containing adsorbent having improved mechanical strength. Carbon nanotubes were surface-oxidized by reacting them with an acid solution, and then reacted with EDA and DCC to introduce amine groups on the surface. Reaction with the divalent metal-containing compound and reaction with the ferrocian-containing compound resulted in the formation of a ferrocyanide- Carbon nanotubes can be obtained. In addition, it has been found that the adsorbent containing the carbon nanotubes fixed with the ferrocyanide metal increases the adsorption capacity for the radionuclide such as cesium as compared with the adsorbent using silica as the conventional support. The present invention is based on this.

On the other hand, when the adsorbent is used in a batch rather than a column type, a separate separation process such as centrifugation is required to separate the radioactive waste in the turbid liquid. Therefore, there is a limitation in disposing of the radionuclide in the field promptly. Accordingly, the ability of the adsorbent of the radionuclide to be separated from the turbid solution in a simpler manner, together with the adsorption ability to the radionuclide, can be a favorable characteristic for the rapid disposal of the radionuclide in the industrial field.

The present inventors have found a method capable of providing an adsorbent having magnetism as a property capable of being separated from an turbid liquid in a simple manner with excellent adsorption ability to a radionuclide. The surface of the carbon nanotube is reacted with an acid solution to oxidize the surface of the carbon nanotube, and then reacted with Fe ²⁺ and Fe ³⁺ metal-containing compound under alkaline conditions to fix the magnetite to the carbon nanotube. It has been found that carbon nanotubes in which a magnetite is fixed on a surface thereof and a ferrocyanide metal is introduced into the magnetite can be obtained. Further, it has been found that the adsorbent containing the carbon nanotubes in which the magnetite is fixed and the ferrocyanide metal is introduced has an adsorption capacity for radionuclides such as cesium as compared with the adsorbent using silica as a conventional support.

As used herein, the term "Carbon Nanotube (CNT)" is a carbon isotope consisting of carbon, which is formed by combining one carbon with another carbon atom in a hexagonal honeycomb pattern, This means a very small area of material at the nanometer level. In carbon nanotubes, one carbon atom forms a hexagonal honeycomb pattern of sp2 bonds with three different atoms. This tube is called a nanotube because the diameter of the tube is very small, about several nanometers. Single-Walled Carbon Nanotubes (SWNTs) have a diameter of about 1 nanometer (nm), and have multi-walled carbon nanotubes (MWNTs) ) Has a total diameter of about 5 to 100 nm. Examples of the synthesis method of carbon nanotubes include an arc-discharge method, a laser vaporization method, a plasma enhanced chemical vapor deposition method, a thermal chemical vapor deposition method, a vapor phase synthesis method growth, electrolysis, and flame synthesis.

In the present invention, a multi-walled carbon nanotube or a single-walled carbon nanotube may be used as the carbon nanotube, and more preferably, the multi-walled carbon nanotube has a larger specific surface area and a pore volume.

According to the present invention, there is provided a carbon nanotube to which a ferrocyanide metal is fixed,

Reacting the carbon nanotubes with an acid solution to obtain surface-oxidized carbon nanotubes (step 1); Reacting the surface-oxidized carbon nanotubes with EDA and DCC to obtain a carbon nanotube having an amine group introduced on the surface thereof (Step 2); The carbon nanotubes into which amine groups have been introduced on the surface are reacted with a divalent metal-containing compound selected from the group consisting of Cu ²⁺ , Ni ²⁺ , Zn ²⁺ , Fe ²⁺ and Co ²⁺ at a concentration of 0.1 to 1 M To obtain a carbon nanotube into which a divalent metal is introduced (step 3); And a step (step 4) of reacting the carbon nanotubes into which the bivalent metal has been introduced with a 0.1 to 1 M concentration ferrocyan-containing compound to obtain a carbon nanotube fixed with ferrocyanide metal .

The step (1) is a step of reacting carbon nanotubes with an acid solution to obtain surface-oxidized carbon nanotubes having a carboxyl group introduced into the surface of the carbon nanotubes.

In the present invention, the acid solution of step 1) may preferably be nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid or a mixture thereof, more preferably nitric acid or a mixture of nitric acid and sulfuric acid. When a mixture of nitric acid and sulfuric acid is used as the acid solution, there is an advantage that the oxidation reaction efficiency on the surface of the carbon nanotubes is high. The mixture of nitric acid and sulfuric acid may have a mixing ratio of nitric acid and sulfuric acid of preferably 1 to 5: 1 (v / v). Specifically, in one embodiment of the present invention, a mixture of nitric acid and sulfuric acid (3: 1, v / v) was used.

In the present invention, the concentration of the acid solution in step 1) may preferably be 5 N to 15 N, more preferably 8 N to 12 N, and most preferably 10 N.

In the present invention, the reaction of step 1) above can be preferably carried out under ultrasonic treatment. The surface of the carbon nanotubes is uniformly dispersed in the acid solution through the ultrasonic treatment to increase the reaction area, thereby efficiently performing the surface oxidation reaction.

In the present invention, the reaction temperature in the step 1) may be preferably 150 to 200 占 폚, more preferably 170 to 180 占 폚, and most preferably 175 占 폚.

In the present invention, the reaction time of the step 1) may be preferably 6 to 24 hours, more preferably 10 to 14 hours, and most preferably 12 hours.

In the present invention, after completion of the reaction of step 1), filtration and ultra-pure water washing may be performed with 0.1 to 0.3 탆 membrane until pH 7 is reached.

Step 2) is a step of reacting the surface-oxidized carbon nanotube with EDA and DCC to replace the OH group of the carboxyl group present on the surface of the carbon nanotube with ethylenediamine to obtain an amine group-introduced carbon nanotube .

In the present invention, the step 2) may be performed by first mixing the surface-oxidized carbon nanotube with EDA, and then adding DCC to the carbon nanotube.

In the present invention, the reaction temperature of step 2) may preferably be 50 to 100 占 폚, more preferably 70 to 90 占 폚, and most preferably 78 占 폚.

In the present invention, the reaction time of the step 2) is preferably 24 hours to 60 hours, more preferably 36 hours to 54 hours, and most preferably 48 hours.

In the present invention, after the reaction of step 2) is completed, the reaction product may be washed with C _1-4 alcohol several times, filtered through 0.1 to 0.3 탆 membrane, and then dried.

Step 3) is a step of reacting a carbon nanotube having an amine group introduced on its surface with a divalent metal-containing compound selected from the group consisting of Cu ²⁺ , Ni ²⁺ , Zn ²⁺ , Fe ²⁺ and Co ²⁺ The amine group and the bivalent metal form a chelate to thereby obtain a carbon nanotube having a bivalent metal introduced on the surface thereof.

In step 3), metal complex ions are formed on the surface of the carbon nanotube by forming a chelate with the ethylenediamine group present on the surface and the bivalent metal.

Containing compound a divalent metal according to the present invention, the step 3) of copper chloride (CuCl _2), copper nitrate (Cu (NO _{3) 2),} copper sulfate (CuSO _4), nickel chloride (NiCl _2), nickel nitrate (Ni (NO ₃ ) ₂ ), nickel sulfate (NiSO ₄ ), zinc chloride (ZnCl ₂ ), zinc nitrate (Zn (NO ₃ ) ₂ ), zinc sulfate (ZnSO ₄ ), ferrous chloride (FeCl ₂ ) (NO ₃ ) ₂ ), ferric sulfate (FeSO ₄ ), cobalt chloride (CoCl ₂ ), cobalt nitrate (Co (NO ₃ ) ₂ ) and cobalt sulfate (CoSO ₄ ) It is not.

In the present invention, the concentration of the divalent copper-containing compound in step 3) may preferably be 0.1 to 1 M, more preferably 0.3 to 0.7 M, and most preferably 0.5 M. If the concentration of the divalent metal-containing compound is less than 0.1 M, the chelating reaction with the amine group present on the surface of the carbon nanotube can not be completely performed. If the concentration exceeds 1 M, unreacted divalent metal ions may remain have.

In the present invention, the reaction solvent in the step 3) may be water or a mixture of water and a C _1-6 alcohol.

In the present invention, the reaction temperature in step 3) may preferably be 10 to 40 ° C.

In the present invention, the reaction time of step 3) may be preferably from 30 minutes to 6 hours.

In the present invention, after completion of the reaction of step 3), the reaction product may be washed with C _1-4 alcohol several times and dried.

In the step 4), the carbon nanotubes into which the divalent metal is introduced are reacted with the ferrocyan-containing compound to bond the ferrocene group to a part of the chelate bond between the divalent metal and the amine group to form the carbon nanotube .

In the present invention, the ferrocyan-containing compound of step 4) may be selected from the group consisting of sodium ferrocyanide and potassium ferrocyanide.

In the present invention, the concentration of the ferrocyan-containing compound in the step 4) may preferably be 0.1 to 1 M, more preferably 0.3 to 0.7 M, and most preferably 0.5 M. If the concentration of the divalent metal-containing compound is less than 0.1 M, the binding reaction of the ferricyanide to the carbon nanotubes can not be completely performed. If the concentration exceeds 1 M, the unreacted compound may remain.

In the present invention, the reaction solvent in the step 4) may be water or a mixture of water and a C _1-6 alcohol for a day.

In the present invention, the reaction temperature in step 4) may be 10 to 40 ° C.

In the present invention, the reaction time of step 4) may be 30 minutes to 6 hours.

In the present invention, after completion of the reaction of step 4), the substrate may be washed with ultrapure water several times and dried.

The method of preparing carbon nanotubes fixed with ferrocyanide according to an embodiment of the present invention is shown in the following reaction formula 1.

[Reaction Scheme 1]

In one embodiment of the present invention, a carbon nanotube having a metal ferrocyanide fixed on the surface thereof is prepared through the production method according to the reaction formula 1, and the adsorbent containing the carbon nanotube with the ferrocyanide- (Example 1 and Experimental Example 2). The adsorbent of the present invention has excellent adsorption ability to the radionuclide such as cesium.

In addition, the carbon nanotube in which the magnetite according to the present invention is immobilized and the ferrocyanide metal is introduced,

Reacting the carbon nanotubes with an acid solution to obtain surface-oxidized carbon nanotubes (step 1); Reacting the surface-oxidized carbon nanotube with Fe ²⁺ and a Fe ³⁺ metal-containing compound under an alkaline condition to obtain a carbon nanotube having a magnetite (Fe ₃ O ₄ ) fixed on its surface (Step 2); And a carbon nanotube on which the magnetite is immobilized on the surface is composed of a ferrocyan-containing compound having a concentration of 0.05 to 0.5 M and a ferrocyanide-containing compound having a concentration of 0.05 to 0.5 M of Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Fe ²⁺ and Co ²⁺ And a step (step 3) of reacting the carbon nanotube with a divalent metal-containing compound selected from the group consisting of iron and cobalt to obtain a carbon nanotube into which ferrocyanide metal is introduced into the magnetite.

The step 1 may be carried out in the same manner as in the step 1 of the method for producing a carbon nanotube in which the ferrocyanide metal is immobilized.

Step 2 is a step of reacting the surface-oxidized carbon nanotubes with Fe ²⁺ and Fe ³⁺ metal-containing compounds under alkaline conditions to obtain carbon nanotubes having magnetic properties with magnetite fixed on their surfaces.

The term "magnetite (Fe ₃ O ₄ )" as used in the present invention means an oxidized mineral composed of iron oxide, which means crystals, lumps, pellets, strata, etc., and can be black glossy. Magnetite is the strongest magnet in the minerals, and it is used as the main raw material for the steel industry.

In the present invention, step 2 can be carried out by in situ chemical coprecipitation. Mixing the surface-oxidized carbon nanotubes with the Fe ²⁺ and Fe ³⁺ metal-containing compounds at a molar ratio of 1: 1.5 to 3, adding an alkali solution, and reacting them.

The in situ chemical coprecipitation used in the present invention is one of methods for producing nano-sized metal oxide particles by simultaneously precipitating various ions in an aqueous solution or a non-aqueous solution. As a method for obtaining a precipitate produced by mixing an alkali solution and a divalent and trivalent metal ions at a predetermined molar ratio and stirring them, it is possible to prevent the initial oxidation of metal ions to obtain uniform and fine nano-sized particles. In addition, since the co-precipitation method produces nanoparticles with low firing temperature, it is easy to manufacture and can be mass-produced in a simple manner.

In the present invention, the magnetite is precipitated on the surface of the carbon nanotubes surface-oxidized through the in situ chemical co-precipitation method as described above to form magnetite particles, and pores may be generated in the magnetite particles during the precipitation. The pore size in the magnetite particles may vary depending on the size of the formed magnetite particles. In the present invention, the magnetite particle size can be nanometric, for example 10 nm to 30 nm. In the present invention, the pore size analysis of the magnetite particles was impossible because the magnetite was fixed to the carbon nanotubes. However, when the pore size of the magnetite particles produced in the absence of the carbon nanotubes was analyzed, Respectively.

In the step 2, the surface-oxidized carbon nanotubes can be dispersed and mixed in a solvent together with Fe ²⁺ and Fe ³⁺ metal-containing compounds. The surface-oxidized carbon nanotubes are dispersed in a solvent together with Fe ²⁺ and Fe ³⁺ metal-containing compounds, preferably in an inert gas atmosphere such as a nitrogen (N ₂ ) gas atmosphere at a temperature of 40 to 60 ° C It can be carried out under ultrasonic treatment.

Then, an alkaline solution is added to the dispersion of the surface-oxidized carbon nanotubes and Fe ²⁺ and Fe ³⁺ metal-containing compounds to induce a coprecipitation reaction to form magnetite fixed on the surface of the surface-oxidized carbon nanotubes. At this time, as described above, the magnetite is formed into a particle shape by coprecipitation, and pores can be formed in the magnetite particles during the coprecipitation process.

In the present invention, the pH of step 2 may be 9 to 12, preferably 11 to 12.

In one embodiment of the present invention, the step 2 is a step of oxidizing the surface-oxidized carbon nanotube with ammonium iron (II) sulfate hexahydrate ((NH ₄ ) ₂ Fe (SO ₄ ) ₂ .6H ₂ O) (NH ₄ OH) to adjust the pH to 11 to 12 by mixing the resulting solution with (III) .12 hydrate (NH ₄ Fe (SO ₄ ) ₂ .12H ₂ O).

In the present invention, the reaction of step 2 can be carried out under ultrasonic treatment. The surface reaction is efficiently performed by increasing the reaction area by uniformly dispersing the carbon nanotubes in the alkali solution through the ultrasonic treatment.

In the present invention, the reaction temperature of step 2 may be 20 to 80 ° C, preferably 40 to 60 ° C.

In the present invention, the reaction time of step 2 may be 20 to 120 minutes.

In the present invention, it is preferable to perform physical stirring after completion of the reaction of step 2 above. Physical agitation can be used to ensure that the carbon nanoparticle crystals are completely formed. The physical stirring may be carried out at a temperature of 40 to 60 DEG C for 10 minutes to 1 hour.

In the present invention, after the physical stirring of step 2 is completed, the carbon nanotube having the magnetite fixed on the surface thereof as a permanent magnet is separated by solid-liquid separation, washed with ultrapure water and C _1-4 alcohol several times, and then dried.

In the step 3, the carbon nanotubes to which the magnetite is fixed on the surface are mixed with a ferrocyan-containing compound and a mixed solution of Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Fe ²⁺ and Co ²⁺ Selected from the group Is reacted with a divalent metal-containing compound to obtain a carbon nanotube having a ferrocyanide metal introduced into the surface and / or pores of the magnetite.

In the present invention, the step 3 may be performed by mixing the magnetite-fixed carbon nanotube with a ferrocyan-containing compound and then adding and adding a divalent metal-containing compound. At this time, the ferrocyan-containing compound is coated on the surface and / or pores of the magnetite by mixing the magnetite-fixed carbon nanotube with the ferrocyan-containing compound, and then the divalent metal-containing compound to be added and the ferrocyan- The ferrocyanide metal is formed on the surface and / or pores of the magnetite. As a result, the carbon nanotube having the ferrocyanide metal introduced into the magnetite can be obtained.

In the present invention, the ferrocyan-containing compound of step 3 may be selected from the group consisting of sodium ferrocyanide and potassium ferrocyanide.

In the present invention, the concentration of the ferrocyan-containing compound in step 3 may be 0.05 to 0.5 M, preferably 0.07 to 0.3 M, as described above.

In the present invention, the divalent metal-containing compound in step 3 is at least one selected from the group consisting of copper chloride (CuCl ₂ ), copper nitrate (Cu (NO ₃ ) ₂ ), copper sulfate (CuSO ₄ ), nickel chloride (NiCl ₂ ) NO ₃ ) ₂ ), nickel sulfate (NiSO ₄ ), zinc chloride (ZnCl ₂ ), zinc nitrate (Zn (NO ₃ ) ₂ ), zinc sulfate (ZnSO ₄ ), ferrous chloride (FeCl ₂ ), ferric nitrate NO ₃ ) ₂ ), ferric sulfate (FeSO ₄ ), cobalt chloride (CoCl ₂ ), cobalt nitrate (Co (NO ₃ ) ₂ ) and cobalt sulfate (CoSO ₄ ) It is not.

In the present invention, the concentration of the divalent metal-containing compound in Step 3 may be 0.05 to 0.5 M, preferably 0.07 to 0.3 M, as described above.

In the present invention, the step 3 is carried out under an inert gas, for example nitrogen (N ₂ ) gas, to prevent side reactions such as peptization in which the solid particles produced by step 3 are redispersed in the solution .

In the present invention, the reaction time in the third step may be 4 to 10 hours.

In the present invention, after the reaction of Step 3 is completed, the carbon nanotubes having the magnetite fixed on the surface and the ferrocyanide metal introduced therein are recovered as a magnet, recrystallized with a 3: 2 ratio of isopropyl alcohol: acetone solution, To perform drying several times.

In one embodiment of the present invention, carbon nanotubes (FIG. 5) in which magnetite is fixed on the surface and zinc ferrocyanide is introduced as a ferrocyanide metal is manufactured through the above manufacturing method. The magnetite is fixed and a metal ferrocyanide It has been confirmed that the adsorbent containing the introduced carbon nanotubes has a better adsorption ability to the radionuclide such as cesium than the adsorbent using silica as the conventional support and can be easily separated from the turbid liquid by the magnet 2 and Experimental Example 6).

Meanwhile, the cesium or strontium adsorbent according to the present invention is characterized in that carbon nanotubes having metal ferrocyanide are fixed on the surface, or carbon nanotubes having magnetite fixed on the surface and ferrocyanide metal is introduced.

The cesium or strontium adsorbent according to the present invention can be used for column or batch cesium or strontium adsorption applications. In particular, when the cesium or strontium adsorbent according to the present invention contains carbon nanotubes fixed with copper ferrocyanide on the surface, the adsorbent is filled in the column to allow the radioactive waste solution to pass through the column to adsorb and remove the radionuclide . In addition, when the cesium or strontium adsorbent according to the present invention contains carbon nanotubes in which magnetite is fixed on the surface and ferrocyanide metal is introduced, it can be used for batch adsorption. In this case, because of the magnetic magnetite, The adsorbent adsorbed with the radioactive nuclei can be easily separated from the turbid solution containing the adsorbent adsorbed by the radioactive nuclei.

According to the present invention, a cesium or strontium adsorbent containing carbon nanotubes to which a metal ferrocyanide is fixed on a surface thereof or a carbon nanotube to which a magnetite is fixed and a ferrocyanide metal is introduced on the surface thereof may be used in combination with a water purification filter or an air purification filter It can be used for the same cesium or strontium removal filter.

The average diameter of the carbon nanotubes to which copper ferrocyanide is fixed on the surface or the carbon nanotubes to which the magnetite is fixed and the ferrocyanide metal is introduced may be 1 to 300 micrometers, A carbon nanotube on which copper ferrocyanide is immobilized on the surface or a filter film having an impermeable mesh size on carbon nanotubes to which ferrocyanide metal is introduced and on which the magnet is fixed. An ultrafiltration membrane (UF) is a non-limiting example of the filter membrane.

Further, purified water can be produced by treating the contaminated water using the cesium or strontium removing filter according to the present invention. At this time, it is possible to remove the radioactive cesium or strontium mainly, and to exert the advantage that ions beneficial to the body are not removed.

Further, the filter for removing cesium or strontium according to the present invention can be used to remove radioactive cesium or strontium from a solution containing a radioactive waste liquid or a radionuclide.

Further, the separation of cesium or strontium according to the present invention can be carried out,

Contacting a cesium or strontium adsorbent with a cesium or strontium containing solution to obtain a cesium or strontium adsorbed adsorbent (step 1); And a step of separating the solution containing the cesium or strontium-adsorbed adsorbent through a channel to which a magnetic field is applied by solid-liquid separation (step 2).

That is, the separation of cesium or strontium according to the present invention can be performed through a solid-liquid separation process of an adsorbent-containing dispersion by an electromagnetic separation method.

In one embodiment, the separation of cesium or strontium according to the present invention can be performed by a solid-liquid separation process as shown in Fig. First, the cesium and / or strontium-containing solution to be separated is put into the adsorption reactor 1, the magnetic adsorbent 2 according to the present invention is added thereto, and then stirred with the agitator 3 to adsorb cesium and / And recovering the magnetic adsorbent adsorbed with cesium and / or strontium by passing the magnetic adsorbent having the cesium and / or strontium adsorbed thereon through the channel (5) equipped with the magnet (4) Then, the filtrate from which the cesium and / or strontium is separated from the cesium and / or strontium-containing solution to be separated by filtration through the membrane filter 6 to remove impurities from the remaining solid phase is introduced into the effluent tank 7, .

The magnetic field may be applied using a permanent magnet or an electromagnet.

The adsorbent adsorbed with cesium or strontium can be easily separated from the slurry containing the adsorbent containing cesium or strontium adsorbed by the solid-liquid separation process according to the present invention, whereby cesium or strontium Cesium or strontium can be separated from the solution by a simple process.

The ferrocyanide metal-immobilized carbon nanotube according to the present invention has an improved mechanical strength and can be used as an adsorbent for a column, and the metal ferrocyanide is fixed through chemical bonding, so that the adsorption ability can be maintained even for a long period of use have. In addition, the carbon nanotube having the magnetite fixed on the surface according to the present invention and the ferrocyanide metal introduced therein is advantageous in that it can be easily separated by the magnetic field during the adsorption process of the batch type by the introduction of the magnetic magnetite.

Fig. 1 (a) shows FT-IR analysis results of MWCNTs and o-MWCNTs.
1 (b) shows the FT-IR analysis results of CuFC-MWCNTs.
Figure 2 shows the results of isothermal adsorption experiments of CuFC-MWCNTs on cesium.
3 shows the results of the specific surface area measurement of the CuFC-MWCNTs of the present invention.
4 is a graph showing a specific surface area measurement result of CuFC-AAHMS of Comparative Example 1. Fig.
5 is a schematic diagram of mag-MWCNTs-ZnFC.
6 is an FE-SEM image of mag-MWCNTs-ZnFC.
7 (a) is an FE-TEM image of mag-MWCNTs-ZnFC.
Fig. 7 (b) shows the elemental analysis results for FE-TEM images of mag-MWCNTs-ZnFC.
Fig. 8 shows the results of the magneto-optic resolution test of mag-MWCNTs-ZnFC. (i) is mag-MWCNTs-ZnFC dispersed in ultrapure water, and (ii) represents mag-MWCNTs-ZnFC separated by permanent magnets.
9 shows the results of magnetic evaluation of mag-MWCNTs-ZnFC.
10 is a result of isothermal adsorption experiments of mag-MWCNTs-ZnFC on cesium.
11 is a schematic view showing a solid-liquid separation process of an adsorbent adsorbing cesium or strontium by an electromagnetic separation method.

Hereinafter, the present invention will be described in more detail with reference to Examples. These embodiments are only for describing the present invention more specifically, and the scope of the present invention is not limited by these examples.

Example 1: Preparation of Carbon Nanotubes Fixed with Ferrocyanide Metal

2.5 g of Pristine MWCNTs (p-MWCNTs) were dispersed in 200 mL of an acid solution mixed with 10 N of HNO ₃ and H ₂ SO ₄ in a volume ratio of 3: 1 by ultrasonication, refluxed at 175 ° C. for 12 hours, (O-MWCNTs) were prepared by filtration through 0.2 ㎛ membrane and washing with ultrapure water.

4 g of the o-MWCNTs were mixed with 150 mL of ethylenediamine (EDA), stirred at 100 rpm for 30 minutes at room temperature, and then refluxed at 78 ° C. for 48 hours at 5 ° C. with DCC (n, n-dicyclohexylcarbodiimide). After refluxing, the solution was washed several times with ethanol, filtered through a 0.2 μm membrane, and dried at 60 ° C. for 12 hours to synthesize amine-introduced MWCNTs (e-MWCNTs).

The e-MWCNTs were mixed with 100 mL of 0.5 M CuCl ₂ / water solution, stirred at room temperature for 2 hours, washed with 2-propanol more than 3 times and dried at 60 ° C for 12 hours to obtain copper- (Cu-MWCNTs) were synthesized.

The Cu-MWCNTs were mixed with 100 mL of 0.5 M Na ₄ Fe (CN) ₆ / water solution, stirred for 2 hours at room temperature, washed with ultrapure water three times or more, and dried at 60 ° C. for 12 hours to obtain ferrocian fixed MWCNTs (FC-MWCNTs) were synthesized.

Example 2: Preparation of carbon nanotubes to which a ferrocyanide metal is immobilized with magnetite fixed

Prepared in Example 1 o-MWCNTs 1 g and _{(NH 4) 2 Fe (SO} 4) 2 · 6H 2 0 1.7 g (4.33 mmol) and _{NH 4 Fe (SO 4) 2} · 12H 2 0 2.51 g ( 8.66 mmol) was ultrasonically dispersed in nitrogen gas (N ₂ ) at 50 ° C for 10 minutes, 10 mL of 8 M NH ₄ OH solution was added, and the mixture was stirred at 50 ° C for 30 minutes. At this time, the pH of the mixed solution was 11. After stirring, the precipitates were separated by solid-liquid separation, and then washed with 150 ml of ethanol and twice as much precipitate as the precipitate, and then dried in a vacuum oven to synthesize magnetite fixed MWCNTs (mag-MWCNTs).

The above mag-MWCNTs in the form of a slurry and 0.1 MK ₄ Fe (CN) ₆ .3H ₂ O were mixed and stirred for 3 hours under a nitrogen gas. Then, 0.1 M ZnCl ₂ was slowly added thereto under agitation and stirred for 3 hours . MWCNTs (mag-MWCNTs-ZnFCs) with metal ferrocyanide introduced into the magnetite were washed and washed several times with ultra-pure water after performing recrystallization reaction with a 3: 2 ratio of isopropyl alcohol: acetone solution, ) Was synthesized (Fig. 5).

COMPARATIVE EXAMPLE 1 Preparation of Organic Silica Fixed with Ferrocyanide Metal

0.55 g of a nonionic surfactant, dodecylamine, was added to 100 mL of a water / ethanol (75 mL: 25 mL) solution and stirred for 12 hours. To the solution were added 17 wt%, 30 wt% (AAPTMS / (TEOS + AAPTMS), TEOS, and AAPTMS with a total weight of 2.75 g) of TEOS and AAPTMS having an organic amino group were stirred for 24 hours at 25 ° C. The synthesized material was filtered, washed with water and ethanol, and dried at 60 ° C to prepare an organic silica (AAHMS). To remove the surfactant in AAHMS, the dried AAHMS was added to 0.003 N HCl / ethanol solution and stirred for 24 hours.

The AAHMS synthesized above was placed in a 0.25 M copper chloride solution, stirred for 2 hours, washed several times with propanol, and dried at 60 ° C to prepare copper-introduced organic silica (Cu-AAHMS) . The prepared Cu-AAHMS was added to a 0.25 M sodium ferrocyanide (Na ₄ Fe (CN) ₆ ) solution, stirred for 2 hours, washed several times with water, and dried at 60 ° C. to obtain an organosilica CuFC-AAHMS).

Experimental Example 1: Confirmation of the Structure of Carbon Nanotubes Fixed with Ferrocyanide Metal of the Present Invention

MWCNTs, o-MWCNTs, and CuFC-MWCNTs were analyzed by Fourier transform infrared spectroscopy (Fourier transform infrared spectroscopy) in order to examine the molecular structure and molecular bonding of the ferrocyanide metal- Spectrophotometer, FT-IR, Spectrum GX and AutoImage, Perkin-Elmer, USA) was performed in the range of 4000-650 cm ^-1 .

The results are shown in Fig. 1 (a) and Fig. 1 (b).

1 (a) shows the results of analysis of MWCNTs and o-MWCNTs. In the case of o-MWCNTs, 3221 cm ^-1 , 1636 cm ^-1 , 1400 cm ^-1 , Stretching vibration of OH, -COO ^- , -COOH, CO was observed at 1097 cm ^-1 . Figure 1 (b) has had a stretching vibration by the NH ₂ of the amine group from a result of the analysis of CuFC-MWCNTs, 3300-3600 cm ^-1, a stretching vibration of CN appeared in the 2080-2200 cm ^-1, o- MWCNTs showed no peaks at 1400 cm ^-1 and peaks at 2080-2200 cm ^-1 , indicating that ferrocyanide metal was introduced into the surface oxidized multi-walled carbon nanotubes.

Experimental Example 2: Investigation of Adsorption Capacity of Carbon Nanotubes Fixed with Ferrocyanide Metal of the Present Invention

The maximum adsorption amounts of CuFC-MWCNTs and CuFC-AAHMS on cesium were evaluated by batch adsorption experiments. As a test method, the amount of the adsorbent was adjusted to 0.1 g, and a cesium simulated waste solution of 1 to 20 mM was prepared with CsNO ₃ (99%, Aldrich Chemical), and the solution was centrifuged at 50 ° C. in a 50 mL conical tube And stirred at 200 rpm for 24 hours. After stirring and centrifuging, the supernatant was filtered through a 0.2 μm syringe filter (Whatman, cellulose nitrate membrane filter, ¢ = 25 mm) and analyzed by inductively coupled plasma emission spectroscopy (ICP-OES, PerkinElmer, Optima 2100 DV). On the other hand, the adsorption rate experiment was performed by adsorption of CuFC-MWCNTs with cesium solution of 2 mM for 10 minutes to 24 hours with different agitation times. The experimental procedure was the same as the above batch adsorption experiment.

The results of isothermal adsorption of CuFC-MWCNTs on cesium are shown in Table 1 and FIG. The maximum adsorption amount of CuFC-MWCNTs for cesium at Cs 20 mM was 1.086 mmol / g when the results were fitted to Langmuir model.

Langmuir q _m
(mmol / g) b
(L / mmol) R ² SSE 1.086 + 0.038 4.167 ± 0.987 0.873 0.097 Freundlich K _F
[(mmol / g) / (mmol / L) ^N ] N
(L / mmol) R ² SSE 0.730 0.030 0.166 + 0.018 0.920 0.077

On the other hand, when the results of isothermal adsorption of CuFC-AAHMS on cesium were fitted to a Langmuir model, the maximum adsorption amount of CuFC-AAHMS on cesium at Cs 20 mM was 0.649 mmol / g.

From the above results, it can be seen that the CuFC-MWCNTs of the present invention show a better adsorption amount of cesium compared to the conventional CuFC-AAHMS.

Experimental Example 3: Measurement of specific surface area of carbon nanotubes fixed with ferrocyanide of the present invention

The specific surface areas of the CuFC-MWCNTs prepared in Example 1 and the CuFC-AAHMS prepared in Comparative Example 1 were measured by a nitrogen adsorption-desorption method using a BET (Brunauer-Emmett-Teller) model.

The specific surface area of the CuFC-MWCNTs of the present invention was found to be 185.9 m 2 / g (FIG. 3), and the specific surface area of CuFC-AAHMS of Comparative Example 1 was found to be 10.5 m 2 / g (FIG. 4) .

From the above results, it can be seen that the CuFC-MWCNTs of the present invention have a larger specific surface area than the conventional CuFC-AAHMS.

Experimental Example 4: Analysis of the shape of carbon nanotubes to which the ferrocyanide metal was immobilized with the magnetite of the present invention

In order to examine the shape of the carbon nanotubes to which the magnetite of the present invention prepared in Example 2 was immobilized and the ferrocyanide metal was introduced, a field emission scanning electron microscope (FE-SEM, SU8220, Hitachi, Japan) (FE-TEM, Titan G2 ChemiSTEM Cs Probe, FEI Company, Netherlands). The image was confirmed. FE-SEM was analyzed with a scale of 15.0 kV, 300 nm, and FE-TEM with a scale of 200.0 kV, 10 nm. In addition, the elemental analysis of the TEM image was performed using the element analyzer included in the FE-TEM analysis equipment.

The results are shown in Figs. 6, 7 (a) and 7 (b).

FIG. 6 is an image of SEM for mag-MWCNTs-ZnFC showing that a magnetite (spherical) was introduced on the MWCNTs (linear) surface.

Fig. 7 (a) is a graph showing the relationship between the mag-MWCNTs-ZnFC FIG. 7 (b) shows that the Zinc hexacyanoferrate containing Zn and N elements was introduced at the position where the Fe and O atoms constituting the magnetite existed as a result of the elemental analysis of the TEM image, It can be seen that zinc cyanide was also partially incorporated into the surface of MWCNTs without magnetite.

Experimental Example 5: Evaluation of magnetic properties of carbon nanotubes in which the magnetite of the present invention is immobilized and ferrocyanide metal is introduced

Magnetic properties of the mag-MWCNTs-ZnFC prepared in Example 2 were analyzed using a vibration sample magnetometer (VSM, Model 7404, Lake Shore, USA) under the conditions of 300K and -15000 to 15000 Field (Oe) .

As a result of the magnetic evaluation of the mag-MWCNTs-ZnFC of the present invention, it was confirmed that the mag-MWCNTs-ZnFC dispersed in the ultra pure water was immediately separated by the permanent magnet (FIG. 8). The magnetization of mag-MWCNTs-ZnFC was found to be 31.01 emu / g (FIG. 9). In FIG. 9, (a) is a magnetite alone, (b) is a mag-MWCNTs in which a magnetite is introduced on the surface of MWCNTs, and (c) is a mag-MWCNTs-ZnFC in which a magnetite is fixed and a ferrocyanide metal is introduced according to the present invention MWCNTs-ZnFC of the present invention does not greatly decrease magnetism as compared with magnetite alone.

Experimental Example 6: A carbon nanotube in which the magnetite of the present invention is immobilized and a ferrocyanide metal is introduced Adsorption capacity investigation

The amount of cesium adsorbed on the mag-MWCNTs-ZnFC prepared in Example 2 was measured in the same manner as in Experimental Example 2 above.

As a result, the maximum cesium adsorption amount of mag-MWCNTs-ZnFC was 0.678 mmol / g (FIG. 10).

From the above results, it can be seen that the carbon nanotube in which the magnetite of the present invention is immobilized and the ferrocyanide metal is introduced exhibits magnetism and shows a cesium adsorption amount superior to the conventional CuFC-AAHMS.

Experimental Example 7: Solid-liquid separation process of adsorbent adsorbing cesium or strontium by electromagnetic separation

As shown in FIG. 11, a solid-liquid separation process using a magnetic field was performed to separate cesium or strontium.

That is, the cesium and / or strontium-containing solution to be separated is put into the adsorption reactor 1, the magnetic adsorbent 2 according to the present invention is added thereto, and then stirred with the agitator 3 to adsorb cesium and / And recovering the magnetic adsorbent adsorbed with cesium and / or strontium by passing the magnetic adsorbent having the cesium and / or strontium adsorbed thereon through the channel (5) equipped with the magnet (4) Then, the filtrate from which the cesium and / or strontium is separated from the cesium and / or strontium-containing solution to be separated by filtration through the membrane filter 6 to remove impurities from the remaining solid phase is introduced into the effluent tank 7, .

Claims (21)

A method for producing a ferrocyanide metal-fixed carbon nanotube comprising the steps of:
Reacting the carbon nanotubes with an acid solution to obtain surface-oxidized carbon nanotubes (step 1);
The surface-oxidized carbon nanotubes are reacted with ethylenediamine (EDA) and n, n-dicyclohexylcarbodiimide (DCC) to obtain carbon nanotubes having an ethylenediamine group introduced on the surface thereof Step (step 2);
The carbon nanotubes to which the ethylenediamine group is introduced on the surface are ^mixed with a divalent metal-containing compound selected from the group consisting of Cu ²⁺ , Ni ²⁺ , Zn ²⁺ , Fe ²⁺ and Co ²⁺ at a concentration of 0.1 to 1 M, To obtain a carbon nanotube into which a divalent metal is introduced (step 3); And
Reacting the carbon nanotube into which the bivalent metal is introduced with a 0.1 to 1 M concentration of the ferrocyan-containing compound to obtain the carbon nanotube having the ferrocyanide (Step 4).
The method of claim 1, wherein the carbon nanotubes are multi-wall carbon nanotubes or single-wall carbon nanotubes.
The method of claim 1, wherein the acid solution of step 1) is nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, or a mixture thereof.
According to claim 1, containing a compound a divalent metal in step 3) is of copper chloride (CuCl _2), copper nitrate (Cu (NO _{3) 2),} copper sulfate (CuSO _4), nickel chloride (NiCl _2), nickel nitrate _{(Ni (NO 3) 2)} , nickel sulfate (NiSO _4), zinc chloride (ZnCl _2), zinc nitrate _{(Zn (NO 3) 2)} , zinc sulfate (ZnSO _4), ferrous chloride (FeCl _2), nitric acid, ferric (Fe (NO ₃ ) ₂ ), ferric sulfate (FeSO ₄ ), cobalt chloride (CoCl ₂ ), cobalt nitrate (Co (NO ₃ ) ₂ ) and cobalt sulfate (CoSO ₄ ) .
The process according to claim 1, wherein the ferrocyan containing compound of step 4) is selected from the group consisting of sodium ferrocyanide and potassium ferrocyanide.
A cesium or strontium adsorbent produced by the method according to claim 1, wherein the cesium or strontium adsorbent contains carbon nanotubes whose surfaces are fixed with metal ferrocyanide.
A method for producing carbon nanotubes in which a magnetite is fixed on a surface including the following steps and a ferrocyanide metal is introduced:
Reacting the carbon nanotubes with an acid solution to obtain surface-oxidized carbon nanotubes (step 1);
The surface-oxidized carbon nanotubes were treated with ammonium iron sulfate (II) hexahydrate ((NH ₄ ) ₂ Fe (SO ₄ ) ₂ .6H ₂ O) and ammonium iron sulfate (III) ₄ Fe (SO _{4) 2} · is reacted with Fe ²⁺ and Fe ³⁺ metal-containing compound is selected from the group consisting of 12H ₂ 0) by inducing the co-precipitation, the magnetite (magnetite, Fe ₃ O ₄₎ on the surface of the fixed Obtaining a carbon nanotube (step 2); And
The carbon nanotubes having the magnetite fixed on the surface are classified into a group consisting of a ferrocyan-containing compound with a concentration of 0.05 to 0.5 M and a group consisting of Cu ²⁺ , Zn ²⁺ , Ni ²⁺ , Fe ²⁺ and Co ²⁺ at a concentration of 0.05 to ^0.5M Selected from To obtain a carbon nanotube having a ferrocyanide metal introduced into the magnetite (Step 3).
8. The method of claim 7,
Wherein the multi-walled carbon nanotube or the single-walled carbon nanotube is used as the carbon nanotube.
8. The method of claim 7,
Wherein the acid solution of step 1) is nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid or a mixture thereof.
delete 8. The method of claim 7,
Wherein the ferrocyan containing compound of step 3) is selected from the group consisting of sodium ferrocyanide and potassium ferrocyanide.
8. The method of claim 7,
2-containing compound the metal of the step 3) of copper chloride (CuCl _2), copper nitrate _{(Cu (NO 3) 2)} , copper sulfate (CuSO _4), nickel chloride (NiCl _2), nickel nitrate (Ni (NO _{3) 2),} nickel sulfate (NiSO _4), zinc chloride (ZnCl _2), zinc nitrate _{(Zn (NO 3) 2)} , zinc sulfate (ZnSO _4), ferrous chloride (FeCl _2), nitric acid, ferric (Fe (NO _{3) 2} ), ferric sulfate (FeSO ₄ ), cobalt chloride (CoCl ₂ ), cobalt nitrate (Co (NO ₃ ) ₂ ) and cobalt sulfate (CoSO ₄ ).
A cesium or strontium adsorbent produced by the method of claim 7, comprising carbon nanotubes to which a ferrocyanide metal is introduced with a magnetite fixed on its surface.
A filter for removing cesium or strontium, comprising the cesium or strontium adsorbent of claim 6 or 13.
15. The filter for removing cesium or strontium according to claim 14, characterized in that it is a filter for purification of water or an air filter.
15. The method of claim 14,
A filter for removing cesium or strontium, comprising a carbon nanotube whose surface is fixed with ferrocyanide metal, or a filter membrane having a non-permeable mesh size for carbon nanotubes to which ferrocyanide metal is introduced, with a magnetite fixed on the surface.
15. The method of claim 14,
Wherein the carbon nanotube having the ferrocyanide metal fixed on the surface thereof or the average diameter of the carbon nanotube having the ferrocyanide metal introduced therein and the magnetite fixed on the surface is 1 micrometer to 300 micrometer.
And passing the contaminated water through the cesium or strontium removal filter according to claim 14.
A radioactive waste solution or a radionuclide is passed through a cesium or strontium removing filter and a magnet according to claim 14 to remove radioactive cesium or strontium.
A method of separating cesium or strontium comprising the steps of:
Contacting the cesium or strontium adsorbent of claim 13 with a cesium or strontium containing solution to obtain a cesium or strontium adsorbed adsorbent (step 1); And
Passing the solution containing the cesium- or strontium-adsorbed adsorbent through a channel to which a magnetic field is applied (step 2).
21. The method of claim 20,
Wherein the magnetic field is applied by a permanent magnet or an electromagnet.

Images