JP2005320219A - Refining method of fullerene - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fullerene refining method by which metal components are removed from a fullerene containing metal components. <P>SOLUTION: In a fullerene refining method by which metal components are removed from a fullerene containing metal components, this method comprises a first process in which a feed fullerene solution is prepared by mixing the feed fullerene with a water-insoluble organic solvent, a second process in which an acid or an alkali aqueous solution is added to the feed fullerene solution and mixed, and a mixed solution of an aqueous solution with transferred metal components and a fullerene solution with the metal components removed are obtained, a third process in which a refined fullerene solution is obtained by removing the aqueous solution from the mixed solution, and a forth process in which fullerene is recovered from the fullerene solution. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for purifying fullerene which removes a metal component from fullerene containing a metal component.

In recent years, as shown in Patent Document 1, fullerenes called C60 and C70, which are closed-shell carbon clusters, have been proposed as new carbon materials. Since these materials are expected to exhibit unique physical properties due to their special molecular structure, research on their properties and application development is proceeding, for example, diamond coating, battery materials, paints, heat insulating materials, lubricants, Application to fields such as pharmaceuticals and cosmetics is expected.

As a fullerene production method, for example, as shown in Patent Document 2, a method of producing a fullerene by burning a carbon compound has been proposed, and now an aromatic hydrocarbon such as benzene and an oxygen-containing gas are introduced into a reaction furnace. A method for producing fullerene by incomplete combustion under reduced pressure has been proposed.
Furthermore, a method has also been proposed in which a soot-like substance containing fullerene is mixed with an organic solvent, the fullerene is dissolved in the organic solvent, and the fullerene is obtained from the organic solvent in which the fullerene is dissolved.

Japanese Patent No. 2802324 Japanese National Publication No. 6-507879

However, the fullerene obtained in the above-described method for producing fullerene by the solvent extraction method includes transition metals such as iron, titanium, chromium, nickel, copper, molybdenum, sodium, potassium, etc. Alkali metals such as calcium, alkaline earth metals such as calcium and magnesium, and metal components such as aluminum are mixed, resulting in a problem that the value of fullerene is lowered. In addition, the metal component to be mixed is taken into the fullerene crystal as a simple substance or attached to the fullerene particles as fine particles such as sodium chloride and metal oxide, and is removed from the powdery fullerene by, for example, a magnetic separator. There was also the problem of not being able to do it.

This invention is made | formed in view of this situation, and it aims at providing the purification method of fullerene which removes a metal component from fullerene containing a metal component.

The method for purifying fullerene according to claim 1, which meets the object, comprises mixing a raw material fullerene solution made of a water-insoluble organic solvent in which a raw material fullerene containing a metal component is dissolved, and an acidic or alkaline aqueous solution.

The method for purifying fullerene according to claim 2, which meets the object, comprises a method for purifying fullerene by removing the metal component from a raw material fullerene containing a metal component.
A first step of preparing a raw material fullerene solution by mixing the raw material fullerene with a water-insoluble organic solvent;
A second step of adding an acidic or alkaline aqueous solution in which the metal component is dissolved to the raw material fullerene solution and mixing, and obtaining a mixed solution of the aqueous solution from which the metal component has been transferred and the fullerene solution from which the metal component has been removed;
A third step of obtaining a purified fullerene solution by removing the aqueous solution from the mixed solution;
And a fourth step of recovering fullerene from the fullerene solution.

Fullerene is (1) a method in which an electrode made of a carbonaceous material such as graphite is used as a raw material, and the raw material is evaporated by arc discharge between the electrodes (arc discharge method), and (2) a raw material is evaporated by passing a high current through the carbonaceous raw material. (3) Method of evaporating carbonaceous raw materials by laser irradiation with high energy density (laser evaporation method), (4) Method of incomplete combustion of organic substances such as benzene (combustion method), etc. It is contained in the rod-like substance manufactured by. The rod-like substance containing fullerene contains polycyclic aromatic hydrocarbons and insoluble carbonized substances.

The raw material fullerene can be obtained by separating these soot-like substances by, for example, a solvent extraction method using the solubility of fullerene in an organic solvent, a sublimation method using the sublimation property of fullerene, or the like. The raw material fullerene is contaminated with metal components such as iron, titanium, calcium, magnesium, chromium, nickel, aluminum, molybdenum, copper, sodium, and potassium due to fullerene production facilities and external contamination.

Note that the soot-containing substance containing fullerene includes a case of a fullerene concentrate obtained by partially removing insoluble carbonized substances from the soot-like substance. The fullerene concentrate is obtained by concentrating fullerene from the soot-like substance by various methods. However, the concentration method is not particularly limited. For example, a fullerene-containing residue obtained by evaporating and drying a fullerene sublimate obtained by a sublimation method or a fullerene solution obtained by a solvent extraction method from a rod-like substance. In addition, fullerene-containing solids obtained by column chromatography separation of soot-like substances, mixtures thereof and the like can be mentioned. The production of the raw material fullerene does not depend on the production method described above.

Here, as the raw material fullerene, in addition to a mixture of any two or more of C60, C70, and fullerene having a molecular weight higher than that obtained by the above-described production method, for example, a single isolated by column chromatography or the like. Also includes a fullerene having a molecular weight.

Water-insoluble organic solvents (hereinafter simply referred to as “organic solvents”) include solvents that are insoluble in water and in which fullerenes are soluble, such as aromatic hydrocarbons, aliphatic hydrocarbons, chlorinated hydrocarbons, and the like. These may be either cyclic or acyclic, and these solvents may be used alone or in combination of two or more.

Here, the aromatic hydrocarbon is a hydrocarbon compound having at least one benzene nucleus in the molecule. For example, benzene, toluene, xylene, ethylbenzene, n-propylbenzene, isopropylbenzene, n-butylbenzene, sec -Butylbenzene, tert-butylbenzene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, 1,2,3,4-tetramethylbenzene, 1, There are alkylbenzenes such as 2,3,5-tetramethylbenzene, diethylbenzene, and cymene, alkylnaphthalenes such as 1-methylnaphthalene and 2-methylnaphthalene, and tetralin.

The aliphatic hydrocarbon can be either cyclic or acyclic. Cycloaliphatic hydrocarbons include monocyclic aliphatic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, cyclooctane, and derivatives thereof such as methylcyclopentane, ethylcyclopentane, methylcyclohexane, ethylcyclohexane, 1 , 2-dimethylcyclohexane, 1,3-dimethylcyclohexane, 1,4-dimethylcyclohexane, isopropylcyclohexane, n-propylcyclohexane, tert-butylcyclohexane, n-butylcyclohexane, isobutylcyclohexane, 1,2,4-trimethylcyclohexane, There is 1,3,5-trimethylcyclohexane, and examples of polycyclic aliphatic hydrocarbons include decalin. Examples of the acyclic aliphatic hydrocarbon include n-pentane, n-hexane, n-heptane, n-octane, isooctane, n-nonane, n-decane, n-dodecane, n-tetradecane and the like.

Further, chlorinated hydrocarbons include dichloromethane, chloroform, carbon tetrachloride, trichloroethylene, tetrachloroethylene, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, chlorobenzene, dichlorobenzene, 1-chloronaphthalene and the like. .
As the organic solvent, ketones having 6 or more carbon atoms, esters having 6 or more carbon atoms, ethers having 6 or more carbon atoms, carbon disulfide, or the like may be used.

Here, from an industrial viewpoint, among these organic solvents, those having a normal temperature liquid and a boiling point of 50 to 300 ° C., particularly 80 to 250 ° C. can be suitably used. Specifically, for example, benzene, toluene, xylene, methicylene, 1-methylnaphthalene, alkylbenzene such as 1,2,3,5-tetramethylbenzene, 1,2,4-trimethylbenzene, and / or naphthalene such as tetralin. Aromatic hydrocarbons such as derivatives are preferably used, and can be used alone or as a mixed solvent of two or more.

The organic solvent has a solubility of fullerene (particularly C60) of 1 g / liter or more, preferably 2 g / liter or more, and more preferably 5 g / liter or more. If the solubility of fullerene is too low, the extraction efficiency decreases. Therefore, as the organic solvent, for example, 1,2,4-trimethylbenzene, o-xylene, and toluene are particularly preferable. The concentration of fullerene in the raw material fullerene solution is usually preferably 90% or less of the saturation solubility of the organic solvent, the lower limit is 0.1% by mass or more, preferably 0.5% by mass or more, and the upper limit is 5% by mass. % Or less, preferably 2% by mass or less.

Here, the raw material fullerene solution composed of a water-insoluble organic solvent in which the raw material fullerene containing the metal component according to claim 1 is dissolved may be any material as long as fullerene is dissolved in the organic solvent. Extracted with an organic solvent, waste liquid when an apparatus with fullerene attached is washed with an organic solvent, and the like.

As the acidic aqueous solution in which the metal component is dissolved, a mixture of one or more of inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid, and organic acids such as acetic acid and methanesulfonic acid is used. It can dissolve metal components such as titanium, calcium, magnesium, chromium, nickel, aluminum, molybdenum, etc. Among them, hydrochloric acid is preferable because it has no reactivity with fullerene and organic solvent and has high solubility of metal components. Used for. The concentration of the acid is not particularly limited, but the lower limit is 0.1% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, and the upper limit is 90% by mass or less, preferably 50% by mass or less. More preferably, it is 20 mass% or less. When the acid concentration is less than 0.1% by mass, the removal amount of the metal component decreases, and when it exceeds 90% by mass, the extraction operation becomes difficult.

Moreover, as an alkaline substance of the alkaline aqueous solution in which the metal component is dissolved, one kind or two or more kinds of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate and the like were mixed. Can be used to dissolve metal components such as aluminum, zinc, tin, lead, etc. Among them, there is no reactivity with fullerenes and organic solvents, and sodium hydroxide is used for reasons such as high solubility of metal components. Preferably used.

The concentration of alkali is not particularly limited, but the lower limit is 0.1% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, and the upper limit is 50% by mass or less, preferably 30% by mass or less. More preferably, it is 20 mass% or less. When the alkali concentration is less than 0.1% by mass, the removal amount of the metal component decreases, and when it exceeds 50% by mass, the extraction operation becomes difficult.
The amount of these aqueous solutions used for the organic solvent is such that the lower limit is 0.1 times or more, preferably 0.5 times or more, and the upper limit is 100 times or less, preferably 10 times or less, more preferably Mix up to 5 times less.

For mixing the raw material fullerene solution and the aqueous solution, a homomixer, an ultrasonic disperser, a static mixer, and a normal stirring tank are used. The mixing time, pressure, temperature, etc. are not particularly limited as long as the raw material fullerene solution and the aqueous solution can be mixed. Moreover, after mixing, as a method of separating into an oil layer having an organic solvent and an aqueous layer having an aqueous solution, the aqueous layer formed below is removed by utilizing the specific gravity difference between the organic solvent and the aqueous solution (that is, water). Gravity stationary separation is suitably performed. Further, it may be forcibly separated by centrifugation.

The method for purifying fullerene according to claim 3 is the method for purifying fullerene according to claim 2, wherein the fullerene solution obtained in the third step is added with an acidic or alkaline aqueous solution to remove the aqueous solution to which the metal component has migrated. The processing to be performed is obtained a plurality of times.
The method for purifying fullerene according to claim 4 is the method for purifying fullerene according to claims 2 and 3, wherein the fullerene solution is washed with water.
In the method for purifying fullerene according to claim 4, washing with water is a treatment for adding and mixing water such as ion-exchanged water and ultrapure water to the fullerene solution obtained in the third step, and further separating the water. This process may be repeated once or twice or more.

In the method for purifying fullerene according to claim 5, in the method for purifying fullerene according to claims 2 to 4, in the fourth step, after the fullerene solution is concentrated, a poor solvent is further added to precipitate fullerene, The poor solvent is removed to obtain solid fullerene.

In the method for purifying fullerene according to claim 5, examples of the poor solvent include alcohols, ketones, ethers and the like. Among these, alcohols having 1 to 4 carbon atoms, ketones having 3 to 5 carbon atoms, or ethers having 3 to 5 carbon atoms are preferable, and alcohols having 1 to 4 carbon atoms are more preferable. Among these alcohols, those having a boiling point lower than that of a water-insoluble organic solvent are preferably used, and alcohols having 3 or less carbon atoms are preferably used. Specifically, methanol, ethanol, n-propanol, isopropanol, ethylene glycol, glycerin and the like are preferable. Among them, isopropanol and methanol are preferable, and methanol is particularly preferable. These poor solvents can be used alone or as a mixture of two or more.

By adding a poor solvent under a specific control, the solubility of the water-insoluble organic solvent in fullerenes decreases, C60, C70 and higher fullerenes having low solubility are precipitated, and impurities having a molecular weight smaller than C60 are Remains in solution. The poor solvent is added for 1 minute or longer, preferably 1 hour or longer, more preferably 3 hours or longer.
The poor solvent is preferably a polar solvent having a solubility of C60 of 0.1 g / liter or less, preferably 10 mg / liter or less. When a poor solvent having a solubility of C60 of 0.1 g / liter or less is used, fullerene is used. Tends to precipitate.

The method for purifying fullerene according to claim 6 is the method for purifying fullerene according to claims 1 to 5, wherein the aqueous solution is added after the raw material fullerene solution is filtered in advance.
The method for purifying fullerene according to claim 7 is the method for purifying fullerene according to claims 1 to 6, wherein the aqueous solution is an acid.

The method for purifying fullerenes according to claim 1 and claims 6 and 7 dependent thereon comprises: a raw material fullerene solution comprising a water-insoluble organic solvent in which a raw material fullerene containing a metal component is dissolved; an acidic or alkaline aqueous solution; Therefore, the metal component can be removed from the water-insoluble organic solvent.

The method for purifying fullerenes according to claim 2 and claims 3 to 7 dependent thereon is an acidic solution in which a metal component is dissolved in a raw material fullerene solution prepared by mixing a raw material fullerene containing a metal component with a water-insoluble organic solvent. Alternatively, an alkaline aqueous solution is added and mixed, and the metal component is transferred from the water-insoluble organic solvent to the aqueous solution to produce fullerene from which the metal component has been removed. Therefore, the value of fullerene can be increased.

In particular, in the method for purifying fullerene according to claim 3, since the fullerene solution is obtained by adding an acidic or alkaline aqueous solution and removing the aqueous solution from which the metal component has been transferred a plurality of times, the metal component can be further removed.
In the fullerene purification method according to the fourth aspect, since the fullerene solution is washed with water, the fullerene solution can be neutralized and can be easily treated in a later step.
In the method for purifying fullerene according to claim 5, in the fourth step, after the fullerene solution is concentrated, a poor solvent is further added to precipitate fullerene, and the poor solvent is removed, so that fullerene can be obtained as a solid. it can.

In the method for purifying fullerene according to claim 6, since the aqueous solution is added after the raw material fullerene solution is previously filtered through a filter, metal powder and the like can be removed beforehand.
In the method for purifying fullerene according to claim 7, since the aqueous solution is an acid, the metal component is easily extracted.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is a flowchart of a fullerene purification method according to an embodiment of the present invention.

A fullerene purification method according to an embodiment of the present invention will be described with reference to FIG.
(First step)
First, a raw material fullerene A containing a metal component in a separable flask equipped with a stirring blade and 1,2,4-trimethylbenzene (1,2,4-trimethylbenzene, which is an example of a water-insoluble organic solvent, hereinafter simply referred to as TMB). B) is supplied and stirred and mixed to prepare a raw material fullerene solution C.

(Second step)
Further, an aqueous hydrochloric acid solution D, which is an example of an acidic or alkaline aqueous solution in which the metal component dissolves, is added to the raw material fullerene solution C, and the mixture is stirred and mixed. A mixed solution G with fullerene solution (TMB) F is obtained. In the mixed solution G, the fullerene solution F is disposed as an oil layer at the top, and the hydrochloric acid aqueous solution E is disposed as a water layer at the bottom.

(Third step)
Next, the cock provided in the lower part of the separable flask is opened, and the lower part aqueous hydrochloric acid E is removed from the mixed solution G to obtain a purified fullerene solution F.
Further, 5% hydrochloric acid aqueous solution H, which is an example of an acidic or alkaline aqueous solution, is added to the fullerene solution F and stirred and mixed. After the metal component in the fullerene solution F is transferred to the hydrochloric acid aqueous solution H, the metal component is further added. Is separated from the aqueous hydrochloric acid solution I, to obtain a fullerene solution J from which the metal components remaining in the fullerene solution F are further removed. This operation may not be performed when the metal component does not remain in the fullerene solution F. When the metal component remains, the aqueous hydrochloric acid solution in which the aqueous metal solution is added and mixed to move the metal component is mixed. The operation of separating I may be repeated once or twice or more.

Ion exchange water K, which is an example of water, is added to and mixed with the fullerene solution J, and then the ion exchange water K is washed with water. This operation is repeated once or twice or more until the acidic fullerene solution J becomes substantially neutral fullerene solution L.

(4th process)
Further, the fullerene solution L is concentrated to obtain a fullerene solution (concentrated solution) M in which fullerene is dissolved at a high concentration. The concentrated liquid M is washed with acetone N, which is an example of a poor solvent, and the precipitated fullerene O is separated by filtration or the like and further dried to obtain solid fullerene P.
Further, since the separated acetone Q contains fullerene, the separated acetone Q is preferably used for washing the concentrate M in order to recover the fullerene.

Example 1
Contains iron over 100 ppm, titanium about 100 ppm, calcium and magnesium about 30 ppm, chromium and nickel about 10 ppm, aluminum about 3 ppm, molybdenum about 1 ppm, and 0.3 mass% ash. 5 g of raw material fullerene and 300 g of TMB were supplied to a 1 liter separable flask equipped with a stirring blade, and stirred and mixed with a stirring blade for 17 minutes to prepare a raw material fullerene solution.

250 g of 5% by mass hydrochloric acid aqueous solution is added to the raw material fullerene solution, mixed by stirring for 10 minutes with a stirring blade, the metal component is transferred to the hydrochloric acid aqueous solution, and the aqueous solution of hydrochloric acid and the fullerene solution from which the metal component has been removed And a mixed solution was obtained. Here, the mixed solution is allowed to stand for 5 minutes, and is separated into a fullerene solution (oil layer) from which the metal component has been removed at the top and an aqueous solution (water layer) from which the metal component has been transferred to the bottom.

The aqueous solution is removed from the cock provided at the bottom of the separable flask. In the separable flask, the metal component is removed, and the purified fullerene solution remains. Further, 250 g of a 5 mass% hydrochloric acid aqueous solution is added to the separable flask, and the mixture is stirred for 10 minutes with a stirring blade to mix the metal components remaining in the fullerene solution, and the aqueous solution is further removed. This operation is added twice, that is, a total of three times with the aqueous hydrochloric acid solution. By this operation, a fullerene solution was obtained.

Further, 250 ml of ion-exchanged water is added to the separable flask, and the mixture is stirred and mixed for 10 minutes with a stirring blade, and the ion-exchanged water is further removed. This washing treatment is performed, for example, three times until the pH of the fullerene solution becomes neutral to obtain a neutralized fullerene solution (oil layer).
Further, the fullerene solution is concentrated to obtain a fullerene solution (concentrated liquid) in which fullerene is dissolved at a high concentration. This concentrated liquid is washed with acetone, and the precipitated fullerene is separated by filtration or the like and further dried to obtain solid fullerene. Table 1 shows analytical values of metal components in the fullerene.

As shown in Table 1, this fullerene contained about 10 ppm of iron, about 3 ppm of titanium, and about 1 ppm of chromium. However, calcium, magnesium, nickel, aluminum and molybdenum were not detected, and ash Was less than 0.1% by mass.

(Example 2)
Example 2 is different from Example 1 in that the concentration of the aqueous hydrochloric acid solution was 0.5% by mass. As shown in Table 1, the fullerene purified thereby contained about 100 ppm of iron, about 30 ppm of titanium, about 10 ppm of chromium, about 3 ppm of magnesium and nickel, and about 1 ppm of calcium, aluminum and molybdenum. In Example 2, the metal component contained in the raw material fullerene was separable, but the removal amount was low due to the low concentration of hydrochloric acid.

(Comparative Example 1)
1 g of raw material fullerene, 45 g of methanol as a poor solvent and 5 g of 5 mass% hydrochloric acid aqueous solution were supplied to a separable flask, stirred for 10 minutes with a stirring blade, and then filtered with a 0.5 μm filter. The residue at this time was put into a separable flask, 9 g of methanol and 1 g of a 5 mass% hydrochloric acid aqueous solution were further supplied, stirred for 10 minutes with a stirring blade, and then filtered with a 0.5 μm filter. The residue at this time was dried under reduced pressure to obtain fullerene. As shown in Table 1, this fullerene contains metal components in which iron exceeds 100 ppm, titanium is about 100 ppm, chromium and nickel and magnesium are about 10 ppm, aluminum is about 3 ppm, and calcium and molybdenum are about 1 ppm. It was.

(Comparative Example 2)
1 g of raw material fullerene and 460 g of TMB are supplied to a separable flask, dissolved and mixed by ultrasonic waves, and then 300 g of methanol and 30 g of a 5 mass% hydrochloric acid aqueous solution are added over 1 hour for crystallization. It was. After separating TMB from the hydrochloric acid aqueous solution, 300 ml of methanol was added to TMB for crystallization, followed by filtration with a 0.5 μm filter. The residue at this time was dried under reduced pressure to obtain fullerene. As shown in Table 1, this fullerene contains metal components in which iron exceeds 100 ppm, titanium is about 100 ppm, chromium and nickel are about 10 ppm, aluminum and magnesium are about 3 ppm, and calcium and molybdenum are about 1 ppm. It was.

As described above, in this embodiment, the raw material fullerene containing a metal component is dissolved in a water-insoluble organic solvent, and then a highly concentrated acidic aqueous solution is added to move the metal component to this aqueous solution. The metal component could be removed from the fullerene.

The present invention is not limited to the above-described embodiment, and can be changed without changing the gist of the present invention. For example, a part or all of the above-described embodiment and modification examples are combined. Thus, the case of constituting the fullerene purification method of the present invention is also included in the scope of the present invention.
For example, in the fullerene purification method of the above embodiment, an aqueous solution may be added after the raw material fullerene solution has been filtered through a filter in advance. Further, when the metal component is aluminum, zinc, tin, lead or the like, the aqueous solution may be alkaline. Although a separable flask equipped with a stirring blade was used for stirring and mixing, a separatory funnel or the like may be used, or mixing may be performed by ultrasonic waves.

In the above embodiment, the fullerene solution is concentrated and then a poor solvent is added to obtain fullerene. However, the fullerene solution may be concentrated to dryness, or only the poor solvent may be added to the fullerene solution. . However, when the fullerene solution is concentrated to dryness, the fullerene hardens on the side wall of the reaction vessel and is sometimes difficult to take out. Further, simply adding a poor solvent to the fullerene solution increases the amount of the poor solvent and takes time. Therefore, it is preferable to add the poor solvent after concentrating the fullerene solution.

Also, a raw material fullerene solution consisting of a water-insoluble organic solvent in which a raw material fullerene containing a metal component is dissolved, for example, an extract obtained by extracting a soot-like substance with an organic solvent, and a device to which fullerene is adhered when the organic solvent is washed It is also possible to mix a waste liquid or the like with an acidic or alkaline aqueous solution and dissolve the metal component in the aqueous solution.

It is a flowchart of the purification method of fullerene which concerns on one embodiment of this invention.

Claims (7)

A method for purifying fullerene, comprising mixing a raw material fullerene solution comprising a water-insoluble organic solvent in which a raw material fullerene containing a metal component is dissolved, and an acidic or alkaline aqueous solution. In the method for purifying fullerene, which removes the metal component from the raw material fullerene containing the metal component,
A first step of preparing a raw material fullerene solution by mixing the raw material fullerene with a water-insoluble organic solvent;
A second step of adding an acidic or alkaline aqueous solution in which the metal component is dissolved to the raw material fullerene solution and mixing to obtain a mixed solution of the aqueous solution from which the metal component has migrated and the fullerene solution from which the metal component has been removed;
A third step of obtaining a purified fullerene solution by removing the aqueous solution from the mixed solution;
And a fourth step of recovering fullerene from the fullerene solution. The fullerene purification method according to claim 2, wherein the fullerene solution obtained in the third step is obtained by adding an acidic or alkaline aqueous solution and removing the aqueous solution to which the metal component has been transferred by performing the treatment a plurality of times. A method for purifying fullerenes, characterized in that 4. The method for purifying fullerene according to claim 2, wherein the fullerene solution is washed with water. 5. 5. The method for purifying fullerene according to claim 2, wherein in the fourth step, after the fullerene solution is concentrated, a poor solvent is further added to precipitate fullerene, and the poor solvent is removed. To obtain a fullerene in solid form. The fullerene purification method according to any one of claims 1 to 5, wherein the raw material fullerene solution is filtered through a filter in advance, and then the aqueous solution is added. The method for purifying fullerene according to any one of claims 1 to 6, wherein the aqueous solution is an acid.

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