JP2023024708A - Method for producing activated carbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing activated carbon having an increased proportion of extremely small-sized micropores of 1 nm or less in diameter, even among micropores of 2 nm or less in diameter.

SOLUTION: This method for producing activated carbon includes an activation step that activates an activated carbon precursor containing a metal component with a carbon dioxide gas as an introduction gas and obtains activated carbon having a ratio (pore volume B/total pore volume A) of the pore volume B of 1.0 nm or less in diameter to the total pore volume A of 0.5 or higher, and a metal element that constitutes the metal component is selected from the group consisting of group 2 elements, group 3 elements, group 4 elements, group 5 elements, group 6 elements, group 7 elements, group 9 elements, and rare earth elements.

SELECTED DRAWING: None

COPYRIGHT: (C)2023,JPO&INPIT

Description

TECHNICAL FIELD The present invention relates to a method for producing activated carbon, and more particularly to a method for producing activated carbon that efficiently produces activated carbon having a high proportion of micropores.

Conventionally, a gas activation method and a chemical activation method are known as activation methods for producing activated carbon. Among these methods, the steam activation method, the carbon dioxide gas activation method, and the oxygen activation method are known as the gas activation method.

From an industrial point of view, the steam activation method, which has a high rate of activation reaction and is advantageous in terms of productivity, is generally used as the gas activation method. In the steam activation method, the activation reaction proceeds through an endothermic reaction between steam and carbon. For example, there is known a method of activating phenolic novolak fibers with steam at 950° C. to obtain activated carbon in an activation time of 120 minutes (see Patent Document 1).
Furthermore, in the steam activation, by including at least one metal component of Mg, Mn, Fe, Y, Pt and Gd in pitch as an activated carbon precursor, the obtained activated carbon has a mesopore mode of 30 to 45 Å. A method for opening mesopores having a diameter is known (see Patent Document 2).

On the other hand, the carbon dioxide activation method is known to have a very low rate of activation reaction. For example, there is known a method of obtaining activated carbon in 24 hours by activating a carbonized coconut shell product with carbon dioxide at 1050° C. (see Patent Document 3). Therefore, the carbon dioxide activation method was not suitable for industrial production.

Patent No. 5781164 JP 2004-182511 A Japanese Patent Application Laid-Open No. 2007-221108

The present inventors industrially produce activated carbon in which, among micropores with a diameter of 2 nm or less, the ratio of extremely small micropores with a diameter of 1 nm or less, which is suitable for adsorption of dichloromethane in the gas phase, is increased. I focused on that. Here, when trying to produce activated carbon with a high proportion of extremely small micropores with a diameter of 1 nm or less, a method of lowering the activation temperature is usually conceivable. However, if the activation temperature is lowered, the activation reaction takes a long time, making it impossible to efficiently produce the product, which is not suitable for industrial production. That is, conventionally, there has been a problem that it is difficult to industrially produce activated carbon with a high proportion of extremely small micropores having a diameter of 1 nm or less. Specifically, for example, in Patent Document 1, Examples 1 to 18 describe activated carbon in which the ratio of micropores with a diameter of 2 nm or less is 0.44 to 0.67. No investigation has been made on activated carbon with an increased proportion of sized micropores and a method for efficiently producing the activated carbon. Further, in Patent Document 2, a method for controlling the distribution of mesopores (2 to 50 nm in diameter), which is much larger than the pore size focused on by the present inventors, to a desired range, specifically the type of a specific metal component It is described to control the mesopore mode diameter of the resulting activated carbon by varying . However, neither activated carbon with an increased proportion of micropores having a diameter of 1 nm or less, which the inventors of the present invention focused on, nor a method for efficiently producing the activated carbon has been studied. In Patent Document 2, the steam activation method is the only example that can be specifically implemented from the viewpoint of controlling the distribution of mesopores within a desired range. In addition, the method of activating a carbonized coconut shell product with carbon dioxide at 1050° C. disclosed in Patent Document 3 has a problem that the activation time is too long and industrial production is difficult. Therefore, Patent Documents 1 to 3 do not disclose or suggest industrial production of activated carbon with an increased proportion of extremely small micropores having a diameter of 1 nm or less.

SUMMARY OF THE INVENTION Accordingly, the main object of the present invention is to provide a method for efficiently producing activated carbon in which, among micropores with a diameter of 2 nm or less, the proportion of extremely small micropores with a diameter of 1 nm or less is increased.

As a result of intensive studies, the present inventors dared to use an activated carbon precursor that has been used to control mesopores, which are pores with a size much larger than the size of the pores that the present inventors have focused on. We paid attention to the technical element of containing metal components and the carbon dioxide activation method, which is known for its extremely low rate of activation reaction. As a result of further intensive studies, by selecting a specific metal and including it in the activated carbon precursor in the carbon dioxide activation method, an activated carbon with an increased ratio of extremely small micropores with a diameter of 1 nm or less was unexpectedly produced. It was found that it can be obtained with a short activation time.
The present invention is an invention completed by further studies based on these findings.

That is, the present invention provides inventions in the following aspects.
Section 1. An activated carbon precursor containing a metal component was activated with carbon dioxide gas as an introduced gas, and the ratio of the pore volume B having a diameter of 1.0 nm or less to the total pore volume A (pore volume B/total pore volume A) was 0.00. 5 or more, wherein the metal elements constituting the metal component are Group 2 elements, Group 3 elements, Group 4 elements, Group 5 elements, Group 7 elements, and rare earth elements. A method for producing activated carbon, which is selected from the group consisting of
Section 2. Item 2. The method for producing activated carbon according to item 1, wherein the metal element is selected from the group consisting of Y, Mg, Mn, La, V, Zr, Ti and Ce.
Item 3. Item 3. The method for producing activated carbon according to Item 1 or 2, wherein the metal element is selected from the group consisting of Y, Mg, Ce, Ti and V.
Section 4. An activated carbon precursor containing a metal component was activated with carbon dioxide gas as an introduced gas, and the ratio of the pore volume B having a diameter of 1.0 nm or less to the total pore volume A (pore volume B/total pore volume A) was 0.00. A method for producing activated carbon, comprising an activation step of obtaining activated carbon of 5 or more, wherein the metal element constituting the metal component is selected from the group consisting of Group 6 elements and Group 9 elements.
Item 5. Item 5. The method for producing activated carbon according to Item 4, wherein the metal element is selected from the group consisting of Mo and Co.
Item 6. Item 6. The method for producing activated carbon according to any one of Items 1 to 5, wherein the activated carbon has a specific surface area of 600 m ² /g or more.
Item 7. Item 7. The method for producing activated carbon according to any one of Items 1 to 6, wherein the composition of the introduced gas is not changed in the activation step.
Item 8. Item 8. The method for producing activated carbon according to any one of Items 1 to 7, wherein the flow rate of the introduced gas is 1.5 L/min or more at 0°C and 1 atmospheric pressure per 1 g of the activated carbon precursor.
Item 9. Item 9. The method for producing activated carbon according to any one of Items 1 to 8, wherein the activation temperature in the activation step is 800 to 1000°C.
Item 10. Item 10. The method for producing activated carbon according to any one of Items 1 to 9, wherein the content of the metal component in the activated carbon precursor is 0.05 to 1.0% by mass.
Item 11. Item 11. The method for producing activated carbon according to any one of Items 1 to 10, wherein the activated carbon precursor is infusible pitch.
Item 12. 12. Any one of items 1 to 11, wherein the activated carbon has a ratio of pore volume C having a diameter of 2.0 nm or less to total pore volume A ({pore volume C/pore volume A}×100) of 85% or more. 1. A method for producing activated carbon according to claim 1.
Item 13. Item 13. The method for producing activated carbon according to any one of Items 1 to 12, wherein the activated carbon has a pore volume B of 0.25 cc/g or more with a diameter of 1.0 nm or less.

INDUSTRIAL APPLICABILITY According to the method for producing activated carbon of the present invention, there is provided a method for efficiently producing activated carbon with an increased proportion of micropores having a diameter of 1 nm or less. Therefore, the time required for activation to a predetermined degree of activation can be greatly shortened, which makes it possible to industrialize activated carbon with high adsorption performance.

1 is a graph showing, by linear approximation, the increasing tendency of specific surface area versus activation time in the production methods of Examples 1-8 and Comparative Examples 1-3. 1 is a graph showing, by linear approximation, the increasing tendency of specific surface area versus activation time in the production methods of Examples 9-15 and Comparative Examples 1-3. 2 is a graph showing, by linear approximation, the increasing tendency of specific surface area versus activation time in the production methods of Examples 16-20 and Comparative Examples 1-3. 10 is a graph showing, by linear approximation, the increasing tendency of the specific surface area with respect to the activation time in the production methods of Examples 21-27 and Comparative Examples 1-3. 10 is a graph showing, by linear approximation, the increasing tendency of the specific surface area with respect to the activation time in the production methods of Comparative Examples 1 to 10. FIG.

Hereinafter, the method for producing activated carbon of the present invention will be described in detail.

[1. Production target (activated carbon)]
[1-1. Surface structure of activated carbon]
Hereinafter, the pore volume refers to the pore volume calculated by the QSDFT method (quenched solid density functional theory). The QSDFT method is an analysis method that can calculate the pore size distribution from about 0.5 nm to about 40 nm for the pore size analysis of geometrically and chemically irregular microporous and mesoporous carbon. . The QSDFT method clearly takes into account the effects of pore surface roughness and non-uniformity, and is therefore a technique that greatly improves the accuracy of pore size distribution analysis. In the present invention, "AUTOSORB-1-MP" manufactured by Quantachrome is used to measure the nitrogen adsorption isotherm and analyze the pore size distribution by the QSDFT method. By applying N2 at 77K on carbon [slit pore, QSDFT equilibrium model] as a calculation model to the desorption isotherm of nitrogen measured at a temperature of 77 K to calculate the pore size distribution, the fineness of a specific pore size range can be obtained. Pore volume can be calculated.

The activated carbon produced by the production method of the present invention has a ratio of the pore volume B (cc/g) having a diameter of 1.0 nm or less to the total pore volume A (cc/g), that is, (pore volume B/total pores Volume A) ratio is 0.5 or more. Generally, pores with a diameter of 2.0 nm or less are referred to as micropores. Good adsorption performance can be obtained. From the viewpoint of obtaining better adsorption performance per unit specific surface area, the (pore volume B/total pore volume A) ratio is preferably 0.53 or more, more preferably 0.60 or more, and still more preferably 0.7. It may be 0.8 or more, particularly preferably 0.8 or more. In the present invention, the adsorption performance can be evaluated by, for example, the adsorption performance of dichloromethane. The upper limit of the (pore volume B/total pore volume A) ratio is not particularly limited, but for example, it may be 1.00 or less, and may be 0.95 or less.

The total pore volume A (cc/g) may be, for example, 0.45 cc/g or more, preferably 0.50 cc/g or more, from the viewpoint of ensuring sufficient pore volume for adsorption.
Further, the total pore volume A (cc/g) is, for example, 1.50 cc/g or less, preferably 0, from the viewpoint of satisfactorily obtaining micropores with a diameter of 2 nm or less, preferably micropores with a diameter of 1 nm or less. .8 cc/g or less.

From the viewpoint of obtaining good adsorption performance, the specific surface area is, for example, 600 m ² /g or more, preferably 1000 m ² /g or more, more preferably 1300 m ² /g or more, still more preferably 1400 m 2 /g or more, particularly preferably 1600 m ² /g or more. ² /g or more.
Although the upper limit of the specific surface area is not particularly limited, for example, it may be 3000 m ² /g or less, 2500 m ² /g or less, or 2000 m ² /g or less.
In the present invention, the specific surface area is a value measured by the BET method (single-point method) using nitrogen as the substance to be adsorbed.

The pore volume B (cc/g) with a diameter of 1.0 nm or less is, for example, 0.25 cc/g or more, preferably 0.35 cc/g or more, from the viewpoint of obtaining good adsorption performance per unit specific surface area. good.
Also, the upper limit of the pore volume B with a diameter of 1.0 nm or less is not particularly limited, but for example, it is 0.60 cc/g or less, preferably 0.50 cc/g or less.

In the activated carbon produced by the production method of the present invention, the pore volume (cc/g) having a diameter of 1.5 nm or less is, for example, 0.45 cc/g or more from the viewpoint of obtaining good adsorption performance per unit specific surface area. Preferably, it may be 0.5 cc/g or more.
Also, the upper limit of the pore volume (cc/g) with a diameter of 1.5 nm or less is not particularly limited, but for example, it is 0.7 cc/g or less.

In the activated carbon produced by the production method of the present invention, the pore volume C (cc/g) having a diameter of 2.0 nm or less is, for example, 0.35 cc/g or more from the viewpoint of obtaining good adsorption performance per unit specific surface area. , preferably 0.45 cc/g or more.
Also, the upper limit of the pore volume C (cc/g) having a diameter of 2.0 nm or less is not particularly limited, but for example, it is 0.8 cc/g or less.

The ratio of pore volume C with a diameter of 2.0 nm or less to total pore volume A ({pore volume C / total pore volume A} × 100, that is, micropore volume ratio (%)) is per unit specific surface area From the viewpoint of obtaining good adsorption performance, it may be, for example, 80% or more, preferably 85% or more, and more preferably 90% or more. In addition, when assuming applications in water purifiers, etc., micropores with a diameter of 1.0 nm or less that effectively contribute to adsorption and moderate mesopores that assist the diffusion of adsorbates in the pores are present. A pore structure may be preferable, and from that point of view, the micropore volume ratio (%) is preferably 80 to 95%, more preferably 90 to 95%. Also, the micropore volume (%) can be greater than 95%, or greater than or equal to 96%.

In the activated carbon produced by the production method of the present invention, the ratio of the pore volume with a diameter of more than 2.0 nm to 50 nm or less to the total pore volume A, that is, the mesopore volume ratio (%) is not particularly limited. In the case of assuming applications such as in, etc., the pore structure has micropores with a diameter of 1.0 nm or less that effectively contribute to adsorption and moderate mesopores that assist the diffusion of the adsorbate in the pores. From that point of view, the mesopore volume ratio is preferably 5 to 20%, more preferably 5 to 10%. Also, the mesopore volume ratio can be less than 5% or 4% or less. In addition, the ratio (%) of the total of the micropore volume and the mesopore volume to the total pore volume A is 98% to 100% (when 100%, the macropore volume ratio (%) is 0%) can be

[1-2. Metal content in activated carbon]
Since the production method of the present invention uses a metal component as described later, the metal component remains in the obtained activated carbon. The ratio of the metal component contained in the activated carbon (in terms of metal element) to the total mass of the activated carbon may be, for example, 0.15 to 0.60% by mass, preferably 0.15 to 0.45% by mass. and more preferably 0.20 to 0.40% by mass. The above ratio in activated carbon is a ratio in terms of metal elements measured by an ICP emission spectrometer (model 715-ES manufactured by Varian).

[1-3. Form of activated carbon]
The form of activated carbon produced by the production method of the present invention is not particularly limited, but examples thereof include granular activated carbon, powdered activated carbon, and fibrous activated carbon. It is more preferable to use a fibrous activated carbon that is fibrous from the viewpoint of workability when it is used after filter processing or the like, or adsorption speed when it is used in a water purifier or the like. In the present invention, the adsorption rate can be evaluated by, for example, a water-flow adsorption test for trihalomethane. The average fiber diameter of fibrous activated carbon is preferably 30 μm or less, more preferably about 5 to 20 μm. In addition, the average fiber diameter in the present invention is a value measured by an image processing fiber diameter measuring device (based on JIS K 1477). Further, as the particle size of granular activated carbon and powdered activated carbon, an integrated volume percentage D ₅₀ measured by a laser diffraction/scattering method is 0.01 to 5 mm.

[1-4. Adsorption performance of activated carbon]
The activated carbon produced by the production method of the present invention can be used either in the gas phase or the liquid phase, and is particularly suitable for adsorbing dichloromethane in the gas phase.

The dichloromethane adsorption performance (equilibrium adsorption amount (% by mass)) that the activated carbon produced by the production method of the present invention can have is, for example, 60% by mass or more, preferably 65% by mass or more, and more preferably 75% by mass. % or more, particularly preferably 80 mass % or more. Incidentally, the dichloromethane adsorption performance is measured as follows. That is, the activated carbon sample is dried in a drier at 110° C. for 12 hours, cooled in a desiccator, and then 0.5 g is quickly weighed and filled in a U-shaped tube. Next, dry air is blown into dichloromethane (special reagent grade, containing 0.5% methanol as a stabilizer) at a flow rate of 500 ml/min in a constant temperature bath at 28°C, and the mixture is introduced into a U-tube for adsorption operation. . The time when the mass of activated carbon stops increasing is regarded as the equilibrium state, and the equilibrium adsorption amount is calculated by the following formula.
Equilibrium adsorption amount (% by mass) = increased mass/mass of activated carbon x 100

The dichloromethane adsorption performance per unit specific surface area that the activated carbon produced by the production method of the present invention can have is 0.045 mass%·g/m ² or more, and 0.046 mass%·g/m 2 or more. ² or more is preferable, specifically 0.046 to 0.055% by mass·g/m ² . The dichloromethane equilibrium adsorption amount per unit specific surface area of activated carbon is calculated by dividing the dichloromethane adsorption performance obtained as described above by the specific surface area (m ² /g) of the activated carbon.

[2. activated carbon precursor]
In the production method of the present invention, the activated carbon precursor, which is the raw material of activated carbon, contains a specific metal component.

[2-1. Raw Material Species of Activated Carbon Precursor]
Carbon dioxide activation is the generation of pores by the reaction between carbon in the activated carbon precursor and carbon dioxide (C _x +CO ₂ →2CO+C _x−1 ). Further, the reaction between carbon and carbon dioxide gas is accelerated by the catalytic action of the metal component, which will be described later. The reaction between carbon and carbon dioxide gas and its promoting effect are common regardless of the raw material species and form of the activated carbon precursor. Therefore, the raw material species and form of the activated carbon precursor are not particularly limited.

Examples of raw materials for activated carbon precursors include infusibilized or carbonized organic materials, curable resins such as phenolic resins, etc. Examples of the organic materials include polyacrylonitrile, pitch, polyvinyl alcohol, cellulose, and the like. is mentioned. Also sawdust, wood chips, wood, peat, charcoal, coconut shells, coal, oil, carbonaceous materials (such as petroleum coke, coal coke, petroleum pitch, coal pitch, coal tar pitch, and combinations thereof), synthetic Examples include resins (phenolic resin, polyacrylonitrile (PAN), polyimide, furan resin, etc.), cellulosic fibers (paper, cotton fiber, etc.), composites thereof (paper-phenolic resin laminates, etc.), and fullerenes. Among these, pitch is preferable, and coal pitch is more preferable, from the viewpoint of the theoretical carbonization yield during carbonization. Examples of forms of activated carbon precursors include granular activated carbon, powdered activated carbon, fibrous activated carbon, and the like.

The softening point (° C.) of the activated carbon precursor is not particularly limited, but is preferably 275° C. to 288° C., more preferably 277° C. to 283° C., from the viewpoint of handleability during infusibilization. In the present invention, the softening point (° C.) is measured by Mettler's method (measured according to ASTM-D3461).

[2-2. Metal component]
The metal component accelerates the reaction between carbon and carbon dioxide in carbon dioxide activation by catalytic action. The metal elements constituting the metal component are group 2 elements, group 3 elements, group 4 elements, group 5 elements, group 6 elements, group 7 elements and group 9 elements, and the group consisting of rare earth elements. One or more species are selected from

One or more of the metal elements constituting the metal component are selected from the group consisting of Group 2 elements, Group 3 elements, Group 4 elements, Group 5 elements, Group 7 elements, and rare earth elements. good. Group 2 elements include Be, Mg, Ca, Sr, Ba and Ra. Sc and Y are mentioned as a group 3 element. Group 4 elements include Ti, Zr, and Hf. Group 5 elements include V, Nb, and Ta. Group 7 elements include Mn, Tc, and Re. Rare earth elements include La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among these, Mg is preferable as the Group 2 element, Y is preferable as the Group 3 element, Zr and Ti are preferable as the Group 4 element, and the 5th V is preferred as the group element, Mn is preferred as the group 7 element, and La and Ce are preferred as the rare earth elements. Furthermore, when assuming applications in water purifiers, etc., micropores with a diameter of 1.0 nm or less that effectively contribute to adsorption and moderate mesopores that assist the diffusion of adsorbates in the pores exist. A pore structure is preferable, and from that point of view, Y, Mg, Ce and Ti are preferable as the metal elements. In addition, when gas adsorption is assumed, it is preferable to increase the specific surface area by maintaining a high ratio of pores with a diameter of 1.0 nm or less. From this point of view, V is preferable as the metal element.
On the other hand, from the viewpoint of controlling the effect of promoting carbon dioxide activation, among the group 2 elements, group 3 elements, group 4 elements, group 5 elements, group 7 elements, and rare earth elements, the above-mentioned Mg, Y, Elements other than Zr, V, Mn, La and Ce can also be selected.

Among the metal elements described above, Mg, Y, La, Zr, Ce, and Ti can be used from the viewpoint of generating mesopores (pores with a diameter of more than 2.0 nm). Moreover, among the metal elements described above, Mg and V can be used from the viewpoint of suppressing the formation of mesopores. Note that when water vapor is contained in the introduced gas, V among the above metal elements can be used from the viewpoint of suppressing the formation of mesopores despite the fact that water vapor is originally a condition that facilitates the formation of mesopores. . Thus, different pore structures of activated carbon can be obtained depending on the metal species. Therefore, the metal element can be appropriately selected according to the pore structure suitable for the application of the activated carbon to be produced.

One or more of the metal elements constituting the metal component may be selected from the group consisting of Group 6 elements and Group 9 elements. Cr, Mo, and W are mentioned as a group 6 element. Group 9 elements include Co, Rh, and Ir. Among these, Mo is preferable as the Group 6 element, and Co is preferable as the Group 9 element, from the viewpoint of obtaining a large effect of promoting carbon dioxide gas activation. Furthermore, when assuming applications in water purifiers, etc., micropores with a diameter of 1.0 nm or less that effectively contribute to adsorption and moderate mesopores that assist the diffusion of adsorbates in the pores exist. A pore structure is preferable, and from that point of view, Co is preferable as the metal element. On the other hand, from the viewpoint of controlling the effect of promoting carbon dioxide gas activation, elements other than Mo and Co described above can be selected from the Group 6 elements and Group 9 elements.

Among the metal elements described above, Mo and Co can be used from the viewpoint of generating mesopores (pores with a diameter of more than 2.0 nm). Among the metal elements described above, Mo can be used from the viewpoint of suppressing the generation of mesopores. When water vapor is contained in the introduced gas, among the metal elements described above, Mo can be used from the viewpoint of suppressing the formation of mesopores despite the fact that water vapor is inherently a condition that facilitates the formation of mesopores. can. Thus, different pore structures of activated carbon can be obtained depending on the metal species. Therefore, the metal element can be appropriately selected according to the pore structure suitable for the application of the activated carbon to be produced.

In the production method of the present invention, the method for adding a metal component to the activated carbon precursor is not particularly limited. For example, the activated carbon precursor may be impregnated with a metal component or kneaded.

The form of the metal component may be a metal simple substance or a metal compound. Examples of metal compounds include inorganic metal compounds such as metal oxides, metal hydroxides, metal halides and metal sulfates, salts of organic acids such as acetic acid and benzoic acid and metals, and organic metal compounds. Examples of organometallic compounds include metal complexes such as metal acetylacetonates and aromatic metal compounds (for example, metallocenes). Metal complexes are preferred because they melt or disperse well in the activated carbon precursor.

The content of the metal component (in terms of metal element) in the activated carbon precursor may be, for example, 0.01 to 1.0% by mass, preferably 0.05 to 0.5% by mass. Furthermore, the content of the metal component in the activated carbon precursor is more preferably 0.05 to 0.4% by mass, more preferably 0.1 to 0.4% by mass, for example when the metal element constituting the metal component is Mg. When the metal element is Mn, it may be more preferably 0.1 to 0.4 mass %, more preferably 0.15 to 0.3 mass %; is Y, more preferably 0.05 to 0.4% by mass, more preferably 0.05 to 0.3% by mass; when the metal element is La, more preferably 0 .1 to 0.4 mass %, more preferably 0.15 to 0.3 mass %; when the metal element is V, more preferably 0.05 to 0.4 mass %, more preferably may be 0.05 to 0.3% by mass; when the metal element is Zr, it is more preferably 0.05 to 0.4% by mass, more preferably 0.1 to 0.3% by mass. when the metal element is Ce, more preferably 0.05 to 0.4% by mass, more preferably 0.1 to 0.3% by mass; when the metal element is Ti may be more preferably 0.1 to 0.4% by mass, still more preferably 0.15 to 0.3% by mass. When the metal element constituting the metal component is Mo, it is more preferably 0.1 to 0.4% by mass, more preferably 0.15 to 0.3% by mass; the metal element is Co. In some cases, it may be more preferably 0.1 to 0.4% by mass, still more preferably 0.15 to 0.3% by mass.

The content of the metal component in the activated carbon precursor is a ratio in terms of metal element measured by an ICP emission spectrometer (Model 715-ES manufactured by Varian).

[2-3. Introduced gas]
Carbon dioxide gas (carbon dioxide) is used as the introduced gas (gas to be introduced into the activation furnace), and nitrogen, carbon monoxide, noble gases, and the like may be contained within a range that does not impair the effects of the present application.

In the present invention, from the viewpoint of efficiently producing activated carbon, it is preferable to carry out the activation process in one step without changing the composition of the introduced gas during the activation process.

The composition of the introduced gas is a value measured according to JIS K 0301 5.1 Orsat analysis method.

From the viewpoint of obtaining good activation efficiency, the flow rate of the introduced gas may be 1.5 L/min or more per 1 g of the activated carbon precursor at 0°C and 1 atm, avoiding excessive introduction and activating efficiently. From a viewpoint, it may be 5.0 L/min or less. This flow rate may be, for example, an amount per about 0.044 m ³ of activation furnace volume.

[2-4. Activation temperature and activation time]
The ambient temperature (activation temperature) in the activation furnace in the activation step may be, for example, 800-1000°C, preferably 900-1000°C.

The activation time may be adjusted according to the main component of the activated carbon precursor, the added metal species, the content of the metal component, the concentration of carbon dioxide in the introduced gas, etc., so as to obtain a predetermined pore distribution. For example, the activation time may be 10-80 minutes, preferably 10-70 minutes. Alternatively, the activation time may be more preferably 15 to 50 minutes, more preferably 25 to 45 minutes, for example, when the metal element constituting the metal component is Mg; when the metal element is Mn, more preferably 15 to 60 minutes, more preferably 20 to 50 minutes; when the metal element is Y, more preferably 15 to 70 minutes, even more preferably 20 to 65 minutes; When the element is La, more preferably 15 to 40 minutes, more preferably 20 to 35 minutes; when the metal element is V, more preferably 10 to 60 minutes, more preferably 15 to 50 minutes; when the metal element is Zr, more preferably 15 to 60 minutes, more preferably 20 to 50 minutes; when the metal element is Ce, more preferably 15 to It may be 55 minutes, more preferably 20 to 50 minutes; when the metal element is Ti, it may be more preferably 15 to 60 minutes, still more preferably 20 to 50 minutes. Alternatively, the activation time may be more preferably 15 to 60 minutes, still more preferably 20 to 50 minutes, for example, when the metal element constituting the metal component is Mo; It may be more preferably 15 to 60 minutes, still more preferably 20 to 50 minutes.

[2-5. Development speed of specific surface area]
According to the production method of the present invention, an activated carbon precursor containing a metal component is activated with carbon dioxide as an introduced gas, and the ratio of the pore volume B having a diameter of 1.0 nm or less to the total pore volume A (pore volume B/ including an activation step of obtaining an activated carbon having a total pore volume A) of 0.5 or more, wherein the metal elements constituting the metal component are Group 2 elements, Group 3 elements, Group 4 elements, and Group 5 elements; , Group 7 elements, and rare earth elements, a method for efficiently producing activated carbon with an increased proportion of micropores with a diameter of 1.0 nm or less is provided. In the present invention, the growth rate of the specific surface area is preferably 25 m ² /g/min or more, more preferably 30 m ² /g/min or more, until the specific surface area reaches 800 m ² /g, for example. 40 m ² /g/min or more is preferable, and 50 m ² /g/min or more is particularly preferable. In addition, the growth rate until the specific surface area reaches 1100 m ² /g is preferably 25 m ² /g/min or more, more preferably 30 m ² /g/min or more, preferably 40 m ² /g/min or more, and 50 m ² /g. g/min or more is particularly preferred.

When the metal element is Y, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 871 m ² /g, the growth rate until the specific surface area reaches 1237 m ² /g, and/or the specific surface area ^The growth rate until reaching 1603 m ² /g is 25 ^{m 2} /g/min or more. and/or the growth rate until reaching a specific surface area of 1338 m ² /g is 30 m ² /g/min or more. When the metal element is Mg, the growth rate of the specific surface area is preferably ³⁰ m ² /g to reach a specific surface area of 981 m 2 /g and/or to reach a specific surface area of 1461 m ² /g. g/min or more. When the metal element is Mn, the growth rate of the specific surface area is preferably ²⁸ m 2 /g to reach a specific surface area of 953 m ² /g and/or to reach a specific surface area of 1214 m ² /g. g/min or more. When the metal element is La, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 675 m ² /g, the growth rate until the specific surface area reaches 758 m ² /g, and/or the specific surface area The growth rate to reach 916 m ² /g is 28 m ² /g/min or more. When the metal element is V, the growth rate of the specific surface area is preferably ⁵⁰ m 2 /g to reach a specific surface area of 863 m ² /g and/or to reach a specific surface area of 1426 m ² /g. g/min or more. When the metal element is Zr, the growth rate of the specific surface area is preferably 25 m 2 ^/ g to reach the specific surface area of 790 m ² /g and/or to reach the specific surface area of 1052 m ² /g. g/min or more. When the metal element is Ce, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 821 m ² /g, the growth rate until the specific surface area reaches 1078 m ² /g, and/or the specific surface area The growth rate to reach 1249 m ² /g is 25 m ² /g/min or more. When the metal element is Ti, the growth rate of the specific surface area is preferably 28 m ² /g to reach a specific surface area of 781 m 2 /g and/or to reach a specific surface area of 1170 m ^{2 /} g. g/min or more.

When the metal element is Y, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 871 m ² /g, the growth rate until the specific surface area reaches 1237 m ² /g, and the specific surface area 1603 m ^{2 .} /g is linearly approximated by the method of least squares (i.e., the growth rate of the specific surface area per minute) is 25 m ² /g/min or more. The least-squares method was applied to the growth rate to reach a specific surface area of 917 m ² /g, the growth rate to reach a specific surface area of 1,168 m ² /g, and the growth rate to reach a specific surface area of 1,338 m ² /g. is 25 m ² /g/min or more when linearly approximated by . When the metal element is Mg, the growth rate of the specific surface area is preferably the least square method of the growth rate until the specific surface area reaches 981 m ² /g and the growth rate until the specific surface area reaches 1461 m ² /g. The value of the slope when linearly approximated with is 30 m ² /g/min or more. When the metal element is Mn, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 953 m ² /g and the growth rate until the specific surface area reaches 1214 m ² /g, respectively, using the least squares method. The value of the slope when linearly approximated with is 15 m ² /g/min or more. When the metal element is La, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 675 m ² /g, the growth rate until the specific surface area reaches 758 m ² /g, and the specific surface area 916 m ^{2 .} 20 m ² /g/min. When the metal element is V, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 863 m ² /g and the growth rate until the specific surface area reaches 1426 m ² /g, respectively, obtained by the method of least squares. The value of the slope when linearly approximated by is 50 m ² /g/min or more. When the metal element is Zr, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 790 m ² /g and the growth rate until the specific surface area reaches 1052 m ² /g, respectively, using the least squares method. The value of the slope when linearly approximated with is 15 m ² /g/min or more. When the metal element is Ce, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 821 m ² /g, the growth rate until the specific surface area reaches 1078 m ² /g, and the specific surface area 1249 m ² . /g is linearly approximated by the method of least squares, and the slope value is 18 m ² /g/min or more. When the metal element is Ti, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 781 m ² /g and the growth rate until the specific surface area reaches 1170 m ² /g, respectively, by the method of least squares. 20 m ² /g/min or more when linearly approximated by .

According to the production method of the present invention, an activated carbon precursor containing a metal component is activated with carbon dioxide as an introduced gas, and the ratio of the pore volume B having a diameter of 1.0 nm or less to the total pore volume A (pore volume B/ It includes an activation step for obtaining an activated carbon having a total pore volume A) of 0.5 or more, and the metal element constituting the metal component is selected from the group consisting of Group 6 elements and Group 9 elements. Provided is a method for efficiently producing activated carbon with an increased proportion of micropores with a very small size of 1.0 nm or less. In the present invention, the growth rate of the specific surface area is preferably 25 m ² /g/min or more, more preferably 30 m ² /g/min or more, until the specific surface area reaches 800 m ² /g, for example. 40 m ² /g/min or more is preferable, and 50 m ² /g/min or more is particularly preferable. In addition, the growth rate until the specific surface area reaches 1100 m ² /g is preferably 25 m ² /g/min or more, more preferably 30 m ² /g/min or more, preferably 40 m ² /g/min or more, and 50 m ² /g. g/min or more is particularly preferred.

When the metal element is Mo, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 784 m ² /g, the growth rate until the specific surface area reaches 1171 m ² /g, and/or the specific surface area The growth rate to reach 1684 m ² /g is 25 m ² /g/min or more. When the metal element is Co, the growth rate of the specific surface area is preferably 30 ^m 2 /g to reach a specific surface area of 844 m ² /g and/or to reach a specific surface area of 1447 m ² /g. g/min or more.

When the metal element is Mo, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 784 m ² /g, the growth rate until the specific surface area reaches 1171 m ² /g, and the specific surface area 1684 m ² . /g is linearly approximated by the method of least squares (i.e., the growth rate of the specific surface area per minute) is 20 m ² /g/min or more. be done. When the metal element is Co, the growth rate of the specific surface area is preferably the growth rate until the specific surface area reaches 844 m ² /g and the growth rate until the specific surface area reaches 1447 m ² /g, respectively, using the method of least squares. The value of the slope when linearly approximated with is 35 m ² /g/min or more.

[2-6. Other processes]
The production method of the present invention may include other steps in addition to the activation step described above. Other steps include known steps in the method of manufacturing activated carbon, for example, a forming step of forming an organic material into a predetermined shape before the activation step (including a spinning step in the case of fibrous activated carbon); Including an infusibilization step is mentioned. Moreover, when the obtained activated carbon is used for water purifiers, a washing step for washing metal components adhering to the surface of the obtained activated carbon can be included after the activation step.

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples. However, the invention is not limited to the examples.

Each example and comparative example was evaluated by the following methods.
(1) Metal content (% by mass) of infusible pitch fiber (activated carbon precursor)
The pitch fiber was subjected to ashing treatment, the ash was dissolved in acid, and the ratio of metal element conversion measured by an ICP emission spectrometer (model 715-ES manufactured by Varian) was used as the metal content.

(2) Composition of Introduced Gas The composition of the introduced gas was measured according to JIS K 0301 5.1 Orsat's analysis method.

(3) Metal Content in Activated Carbon Fibrous activated carbon was dissolved in acid, and the ratio of metal element conversion measured by an ICP emission spectrometer (model 715-ES manufactured by Varian) was used as the metal content.

(4) Specific surface area (m ² /g) and pore volume (cc/g)
The specific surface area was calculated from the measurement point at a relative pressure of 0.1 by the BET method.
The pore physical properties were measured from the nitrogen adsorption isotherm at 77K using "AUTOSORB-1-MP" manufactured by Quantachrome. The total pore volume and the pore volume in each pore size range described in each table below are obtained by applying N _at 77K on carbon [slit pore, QSDFT equilibrium model] as a calculation model to the measured nitrogen desorption isotherm. was analyzed by calculating the pore size distribution. Specifically, the pore volume at each pore size described in each table below is the read value of the pore size distribution diagram obtained from the nitrogen adsorption/desorption isotherm. More specifically, the pore volume B with a pore diameter of 1.0 nm or less is the read value of Cumulative Pore Volume (cc/g) when the horizontal axis Pore Width of the pore diameter distribution diagram is 1.0 nm. Similarly, a pore volume with a pore diameter of 1.5 nm or less and a pore (that is, micropore) volume C with a pore diameter of 2.0 nm or less were obtained.
The pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was calculated by dividing the pore volume B with a pore diameter of 1.0 nm or less by the total pore volume A obtained by QSDFT analysis. The micropore volume ratio ({C/A}×100) was expressed as a percentage by dividing the pore volume C with a pore diameter of 2.0 nm or less by the total pore volume A given by QSDFT analysis. The mesopore volume ratio (%) was calculated by subtracting the micropore volume ratio (%) from 100%.

(5) Growth Rate of Pores of 1.0 nm or Less and Growth Rate of Specific Surface Area The growth rate of pores of 1.0 nm or less was calculated by dividing the pore volume B of 1.0 nm or less by the activation time. The development rate of the specific surface area was calculated by dividing the BET specific surface area by the activation time.

(6) Fiber diameter of fibrous activated carbon (μm)
Measured with an image processing fiber diameter measuring device (according to JIS K 1477).

(Example 1)
As an organic material, 0.5 parts by mass of trisacetylacetonatoitrium (CAS number: 15554-47-9) as a metal component is added to 100 parts by mass of granular coal pitch having a softening point of 280° C. and mixed. The mixture was supplied to a melt extruder, melt-mixed at a melting temperature of 320° C., and spun at a discharge rate of 16 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The yttrium content in the activated carbon precursor was 0.10% by mass.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment in an activation furnace at an atmospheric temperature of 950° C. for 32 minutes, and activated carbon of Example 1 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 871 m ² /g, a total pore volume A of 0.336 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.305 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.907.

(Example 2)
Activated carbon of Example 2 was obtained in the same manner as in Example 1, except that the activation time was changed to 44 minutes. The obtained activated carbon has a specific surface area of 1237 m ² /g, a total pore volume A of 0.491 cc/g, a micropore volume ratio ({C/A}×100) of 99%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.383 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.779.

(Example 3)
Activated carbon of Example 3 was obtained in the same manner as in Example 1, except that the activation time was 58 minutes. The obtained activated carbon has a specific surface area of 1603 m ² /g, a total pore volume A of 0.654 cc/g, a micropore volume ratio ({C/A}×100) of 97%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.434 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.663.

(Example 4)
Same as Example 1, except that the added amount of the metal component (trisacetylacetonatoitrium) was 1.0 parts by mass (the metal content in the activated carbon precursor was 0.16 mass%) and the activation time was 25 minutes. and activated carbon of Example 4 was obtained. The obtained activated carbon has a specific surface area of 917 m ² /g, a total pore volume A of 0.381 cc/g, a micropore volume ratio ({C/A}×100) of 95%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.278 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.730.

(Example 5)
Activated carbon of Example 5 was obtained in the same manner as in Example 4, except that the activation time was 32 minutes. The obtained activated carbon has a specific surface area of 1168 m ² /g, a total pore volume A of 0.502 cc/g, a micropore volume ratio ({C/A}×100) of 92%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.302 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.602.

(Example 6)
Activated carbon of Example 6 was obtained in the same manner as in Example 4, except that the activation time was changed to 40 minutes. The obtained activated carbon has a specific surface area of 1338 m ² /g, a total pore volume A of 0.592 cc/g, a micropore volume ratio ({C/A}×100) of 90%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.352 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.595.

(Example 7)
As an organic material, a mixture of 2.3 parts by mass of acetylacetone magnesium (II) (CAS number: 14024-56-7) and 100 parts by mass of granular coal pitch having a softening point of 280°C is supplied to the melt extruder. Then, they were melt-blended at a melting temperature of 320° C. and spun at a discharge rate of 16 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The content of magnesium in the activated carbon precursor was 0.18% by mass.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment at an atmospheric temperature of 950° C. for 25 minutes in an activation furnace, and activated carbon of Example 7 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 981 m ² /g, a total pore volume A of 0.395 cc/g, a micropore volume ratio ({C/A}×100) of 95%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.331 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.838.

(Example 8)
Activated carbon of Example 8 was obtained in the same manner as in Example 7, except that the activation time was changed to 40 minutes. The obtained activated carbon has a specific surface area of 1461 m ² /g, a total pore volume A of 0.635 cc/g, a micropore volume ratio ({C/A}×100) of 87%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.417 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.656.

(Example 9)
As an organic material, a mixture of 100 parts by mass of granular coal pitch having a softening point of 280 ° C. and 1.7 parts by mass of manganese benzoate (CAS number: 636-13-5) is supplied to a melt extruder, Pitch fibers were obtained by melt mixing at a melting temperature of 320° C. and spinning at a discharge rate of 16 g/min. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The content of manganese in the activated carbon precursor was 0.20% by mass.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment at an atmospheric temperature of 950° C. for 25 minutes in an activation furnace, and activated carbon of Example 9 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 953 m ² /g, a total pore volume A of 0.367 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.345 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.941.

(Example 10)
Activated carbon of Example 10 was obtained in the same manner as in Example 9, except that the activation time was changed to 40 minutes. The obtained activated carbon has a specific surface area of 1214 m ² /g, a total pore volume A of 0.484 cc/g, a micropore volume ratio ({C/A}×100) of 98%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.348 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.720.

(Example 11)
As an organic material, a mixture of 100 parts by mass of granular coal pitch having a softening point of 280° C. and 1.3 parts by mass of acetylacetonatolanthane (CAS number: 64424-12-0) was supplied to the melt extruder. , melt-mixed at a melting temperature of 320°C, and spun at a discharge rate of 16 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The lanthanum content in the activated carbon precursor was 0.21% by mass.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was carried out by heat treatment in an activation furnace at an atmospheric temperature of 950° C. for 20 minutes, and activated carbon of Example 11 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 675 m ² /g, a total pore volume A of 0.267 cc/g, a micropore volume ratio ({C/A}×100) of 99%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.234 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.875.

(Example 12)
Activated carbon of Example 12 was obtained in the same manner as in Example 11, except that the activation time was changed to 25 minutes. The obtained activated carbon has a specific surface area of 758 m ² /g, a total pore volume A of 0.304 cc/g, a micropore volume ratio ({C/A}×100) of 97%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.256 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.841.

(Example 13)
Activated carbon of Example 13 was obtained in the same manner as in Example 11, except that the activation time was changed to 30 minutes. The obtained activated carbon has a specific surface area of 916 m ² /g, a total pore volume A of 0.368 cc/g, a micropore volume ratio ({C/A}×100) of 96%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.283 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.770.

(Example 14)
As an organic material, 1.3 parts by mass of bis(2,4-pentanedionato) vanadium (IV) oxide (CAS number: 3153-26-2) is added to 100 parts by mass of granular coal pitch having a softening point of 280°C. The mixed material was supplied to a melt extruder, melt-mixed at a melting temperature of 320° C., and spun at a discharge rate of 16 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The vanadium content in the activated carbon precursor was 0.18 mass %.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment in an activation furnace at an atmospheric temperature of 950° C. for 15 minutes, and activated carbon of Example 14 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 863 m ² /g, a total pore volume A of 0.332 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.305 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.918.

(Example 15)
Activated carbon of Example 15 was obtained in the same manner as in Example 14, except that the activation time was changed to 25 minutes. The obtained activated carbon has a specific surface area of 1426 m ² /g, a total pore volume A of 0.569 cc/g, a micropore volume ratio ({C/A}×100) of 97%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.437 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.767.

(Example 16)
As an organic material, a mixture of 100 parts by mass of granular coal pitch having a softening point of 280° C. and 0.8 parts by mass of acetylacetonatozirconium (CAS number: 17501-44-9) was supplied to the melt extruder. , melt-mixed at a melting temperature of 320°C, and spun at a discharge rate of 16 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The zirconium content in the activated carbon precursor was 0.19 mass %.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment at an atmospheric temperature of 950° C. for 25 minutes in an activation furnace, and activated carbon of Example 16 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 790 m ² /g, a total pore volume A of 0.317 cc/g, a micropore volume ratio ({C/A}×100) of 97%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.259 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.817.

(Example 17)
Activated carbon of Example 17 was obtained in the same manner as in Example 16, except that the activation time was changed to 40 minutes. The obtained activated carbon has a specific surface area of 1052 m ² /g, a total pore volume A of 0.445 cc/g, a micropore volume ratio ({C/A}×100) of 91%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.315 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.707.

(Example 18)
As an organic material, a mixture of 100 parts by mass of granular pitch having a softening point of 280° C. and 0.8 parts by mass of cerium acetylacetonate (CAS number: 15653-01-7) is supplied to a melt extruder, Pitch fibers were obtained by melt mixing at a melting temperature of 320° C. and spinning at a discharge rate of 16 g/min. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The content of cerium in the activated carbon precursor was 0.14 mass %.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was carried out by heat treatment in an activation furnace at an atmospheric temperature of 950° C. for 25 minutes, and activated carbon of Example 18 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 821 m ² /g, a total pore volume A of 0.341 cc/g, a micropore volume ratio ({C/A}×100) of 92%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.276 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.808.

(Example 19)
Activated carbon of Example 19 was obtained in the same manner as in Example 18, except that the activation time was changed to 35 minutes. The obtained activated carbon has a specific surface area of 1078 m ² /g, a total pore volume A of 0.464 cc/g, a micropore volume ratio ({C/A}×100) of 89%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.337 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.726.

(Example 20)
Activated carbon of Example 20 was obtained in the same manner as in Example 18, except that the activation time was changed to 45 minutes. The obtained activated carbon has a specific surface area of 1249 m ² /g, a total pore volume A of 0.550 cc/g, a micropore volume ratio ({C/A}×100) of 88%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.352 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.641.

(Example 21)
As an organic material, 0.8 parts by mass of (2,4-pentanedionato) molybdenum (VI) dioxide (CAS number: 17524-05-9) was mixed with 100 parts by mass of granular pitch having a softening point of 280°C. The mixture was supplied to a melt extruder, melt-mixed at a melting temperature of 320° C., and spun at a discharge rate of 16 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The content of molybdenum in the activated carbon precursor was 0.23% by mass.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment in an activation furnace at an atmospheric temperature of 950° C. for 25 minutes, and activated carbon of Example 21 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 784 m ² /g, a total pore volume A of 0.313 cc/g, a micropore volume ratio ({C/A}×100) of 98%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.269 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.861.

(Example 22)
Activated carbon of Example 22 was obtained in the same manner as in Example 21, except that the activation time was changed to 40 minutes. The obtained activated carbon has a specific surface area of 1171 m ² /g, a total pore volume A of 0.479 cc/g, a micropore volume ratio ({C/A}×100) of 95%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.365 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.761.

(Example 23)
Activated carbon of Example 23 was obtained in the same manner as in Example 21, except that the activation time was changed to 60 minutes. The obtained activated carbon has a specific surface area of 1684 m ² /g, a total pore volume A of 0.714 cc/g, a micropore volume ratio ({C/A}×100) of 92%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.427 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.598.

(Example 24)
As an organic material, a mixture of 100 parts by mass of granular pitch having a softening point of 280° C. and 1.5 parts by mass of cobalt acetylacetonatocobalt (CAS number: 21679-46-9) is supplied to a melt extruder, Pitch fibers were obtained by melt mixing at a melting temperature of 320° C. and spinning at a discharge rate of 16 g/min. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The content of cobalt in the activated carbon precursor was 0.21% by mass.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment at an atmospheric temperature of 950° C. for 25 minutes in an activation furnace, and activated carbon of Example 25 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 844 m ² /g, a total pore volume A of 0.357 cc/g, a micropore volume ratio ({C/A}×100) of 89%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.315 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.882.

(Example 25)
Activated carbon of Example 25 was obtained in the same manner as in Example 24, except that the activation time was changed to 40 minutes. The obtained activated carbon has a specific surface area of 1447 m ² /g, a total pore volume A of 0.616 cc/g, a micropore volume ratio ({C/A}×100) of 89%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.431 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.700.

(Example 26)
As an organic material, 1.4 parts by mass of bis(2,4-pentanedionato)titanium (IV) oxide (CAS number: 14024-64-7) is mixed with 100 parts by mass of granular pitch having a softening point of 280°C. The mixture was supplied to a melt extruder, melt-mixed at a melting temperature of 320° C., and spun at a discharge rate of 16 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The content of titanium in the activated carbon precursor was 0.25% by mass.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment at an atmospheric temperature of 950° C. for 25 minutes in an activation furnace, and activated carbon of Example 26 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 781 m ² /g, a total pore volume A of 0.335 cc/g, a micropore volume ratio ({C/A}×100) of 89%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.240 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.717.

(Example 27)
Activated carbon of Example 27 was obtained in the same manner as in Example 26, except that the activation time was changed to 40 minutes. The obtained activated carbon has a specific surface area of 1170 m ² /g, a total pore volume A of 0.557 cc/g, a micropore volume ratio ({C/A}×100) of 80%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.320 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.575.

(Comparative example 1)
As an organic material, granular coal pitch having a softening point of 280° C. was supplied to a melt extruder, melt-mixed at a melting temperature of 320° C., and spun at a discharge rate of 20 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. Since no metal component was added, the metal content of the activated carbon precursor was 0% by mass.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment at an atmospheric temperature of 950° C. for 60 minutes in an activation furnace, and activated carbon of Comparative Example 1 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 814 m ² /g, a total pore volume A of 0.315 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.311 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.988.

(Comparative example 2)
Activated carbon of Comparative Example 2 was obtained in the same manner as in Comparative Example 1, except that the activation time was changed to 90 minutes. The obtained activated carbon has a specific surface area of 1304 m ² /g, a total pore volume A of 0.497 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.428 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.862.

(Comparative Example 3)
Activated carbon of Comparative Example 3 was obtained in the same manner as in Comparative Example 1 except that the activation time was set to 125 minutes. The obtained activated carbon has a specific surface area of 1741 m ² /g, a total pore volume A of 0.692 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.462 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.667.

(Comparative Example 4)
As an organic material, a mixture of 100 parts by mass of granular coal pitch having a softening point of 280° C. and 1.3 parts by mass of zinc caprylate (CAS number: 557-09-5) as a metal component is melt-extruded. The mixture was supplied to a machine, melt-mixed at a melting temperature of 320° C., and spun at a discharge rate of 16 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The content of zinc in the activated carbon precursor was 0.19% by mass.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment in an activation furnace at an atmospheric temperature of 950° C. for 60 minutes, and activated carbon of Comparative Example 4 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 1021 m ² /g, a total pore volume A of 0.387 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.383 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.991.

(Comparative Example 5)
Activated carbon of Comparative Example 5 was obtained in the same manner as in Comparative Example 4 except that the activation time was set to 100 minutes. The obtained activated carbon has a specific surface area of 1484 m ² /g, a total pore volume A of 0.577 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.467 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.809.

(Comparative Example 6)
As an organic material, 100 parts by mass of granular coal pitch having a softening point of 280° C. and 1.0 parts by mass of copper acetylacetonato (CAS number: 13395-16-9) as a metal component are added and mixed. The mixture was supplied to an extruder, melt-mixed at a melting temperature of 320° C., and spun at a discharge rate of 16 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The content of copper in the activated carbon precursor was 0.18 mass %.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment in an activation furnace at an atmospheric temperature of 950° C. for 60 minutes, and activated carbon of Comparative Example 6 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 1125 m ² /g, a total pore volume A of 0.427 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.416 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.974.

(Comparative Example 7)
Activated carbon of Comparative Example 7 was obtained in the same manner as in Comparative Example 6 except that the activation time was set to 130 minutes. The obtained activated carbon has a specific surface area of 1690 m ² /g, a total pore volume A of 0.681 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.415 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.610.

(Comparative Example 8)
As an organic material, 0.7 parts by mass of silver sebacate as a metal component was added to 100 parts by mass of granular coal pitch having a softening point of 280°C, and the mixture was supplied to a melt extruder and melted at a melting temperature of 320°C. Pitch fibers were obtained by melt mixing and spinning at a discharge rate of 16 g/min. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The silver content in the activated carbon precursor was 0.27 mass %.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume 0.044 m ³ ), and an introduced gas having a CO ₂ concentration of 100% by volume and a temperature of about 20°C was introduced at a flow rate of about 15 L/min (converted at 0°C and 1 atm). It was introduced into the activation furnace. Activation was performed by heat treatment at an atmospheric temperature of 950° C. for 25 minutes in an activation furnace, and activated carbon of Comparative Example 8 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 389 m ² /g, a total pore volume A of 0.156 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.156 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.999.

(Comparative Example 9)
Activated carbon of Comparative Example 9 was obtained in the same manner as in Comparative Example 8, except that the activation time was changed to 100 minutes. The obtained activated carbon has a specific surface area of 1280 m ² /g, a total pore volume A of 0.495 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.397 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.802.

(Comparative Example 10)
Activated carbon of Comparative Example 10 was obtained in the same manner as in Comparative Example 8 except that the activation time was set to 130 minutes. The obtained activated carbon has a specific surface area of 1730 m ² /g, a total pore volume A of 0.700 cc/g, a micropore volume ratio ({C/A}×100) of 100%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.420 cc/g, and the pore volume ratio (B/A) of pore diameters of 1.0 nm or less was 0.600.

(Comparative Example 11)
As an organic material, 100 parts by mass of granular coal pitch having a softening point of 280° C. and 1.3 parts by mass of trisacetylacetonatoitrium (CAS number: 15554-47-9) as a metal component are added and mixed. The mixture was supplied to a melt extruder, melt-mixed at a melting temperature of 320° C., and spun at a discharge rate of 16 g/min to obtain pitch fibers. The obtained pitch fibers were heated in the air from room temperature to 354° C. at a rate of 1 to 30° C./min for 54 minutes to perform an infusibilization treatment, thereby obtaining an activated carbon precursor as infusible pitch fibers. The yttrium content in the activated carbon precursor was 0.25 mass %.

10 g of the obtained activated carbon precursor was charged into an activation furnace (volume: 0.044 m ³ ), and an introduction gas having an H ₂ O concentration of 100% by volume was introduced into the activation furnace at a flow rate of about 1.0 kg/hr. Activation was performed by heat treatment at an atmospheric temperature of 900° C. for 20 minutes in an activation furnace, and activated carbon of Comparative Example 11 was obtained. The composition of the introduced gas was not changed during the activation process. The obtained activated carbon has a specific surface area of 1078 m ² /g, a total pore volume A of 0.572 cc/g, a micropore volume ratio ({C/A}×100) of 72%, and a pore diameter of 1.0 nm or less. The pore volume B was 0.241 cc/g, and the pore volume ratio (B/A) with a pore diameter of 1.0 nm or less was 0.421.

Tables 1 to 5 show the production conditions and physical properties of the activated carbons obtained by the production methods of Examples 1 to 27 and Comparative Examples 1 to 11. 1 to 5 are graphs showing linear approximation of the increasing tendency of the specific surface area with respect to the activation time in the production methods of Examples 1 to 27 and Comparative Examples 1 to 10.

As shown in Tables 1 to 3, in the production methods of Examples 1 to 27, a specific metal component was included in the activated carbon precursor and carbon dioxide gas activation was performed to obtain a diameter of 1.5% with respect to the total pore volume A. An activated carbon having a pore volume B ratio of 0 nm or less (pore volume B/total pore volume A) of 0.5 or more was obtained. Furthermore, as shown in FIGS. 1 to 4, in the production methods of Examples 1 to 27, the development rate of the specific surface area is higher than in Comparative Examples 1 to 10 (see FIG. 5), and the introduced gas is dioxide It was shown that activated carbon can be produced efficiently even with carbon dioxide gas activation of 100% carbon. In other words, the activation time required for activation to a predetermined specific surface area was greatly shortened. In particular, Examples 14 and 15 using metal components containing vanadium have a remarkably high growth rate of the specific surface area.

On the other hand, as shown in Tables 4 and 5 and FIG. 5, in Comparative Examples 1 to 10, the growth rate of the specific surface area is small, and activated carbon cannot be produced efficiently. In addition, as shown in Comparative Examples 4 to 10, even when a metal component is included in the activated carbon precursor and carbon dioxide gas activation is performed, if the metal component does not contain the specific metal element in the present invention, The development speed of the specific surface area cannot be increased. Further, as shown in Table 5, in Comparative Example 11, although a specific metal component was included in the activated carbon precursor, activation was performed by the steam activation method. The following pore volume B ratio (pore volume B/total pore volume A) was less than 0.5.

Claims (13)

An activated carbon precursor containing a metal component was activated with carbon dioxide as an introduced gas, and the ratio of the pore volume B having a diameter of 1.0 nm or less to the total pore volume A (pore volume B/total pore volume A) was 0.00. including an activation step to obtain activated carbon of 5 or more,
A method for producing activated carbon, wherein the metal element constituting the metal component is selected from the group consisting of Group 2 elements, Group 3 elements, Group 4 elements, Group 5 elements, Group 7 elements, and rare earth elements. . 2. The method for producing activated carbon according to claim 1, wherein said metal element is selected from the group consisting of Y, Mg, Mn, La, V, Zr, Ti and Ce. 3. The method for producing activated carbon according to claim 1, wherein said metal element is selected from the group consisting of Y, Mg, Ce, Ti and V. An activated carbon precursor containing a metal component was activated with carbon dioxide gas as an introduced gas, and the ratio of the pore volume B having a diameter of 1.0 nm or less to the total pore volume A (pore volume B/total pore volume A) was 0.00. including an activation step to obtain activated carbon of 5 or more,
A method for producing activated carbon, wherein the metal element constituting the metal component is selected from the group consisting of Group 6 elements and Group 9 elements. 5. The method for producing activated carbon according to claim 4, wherein said metal element is selected from the group consisting of Mo and Co. The method for producing activated carbon according to any one of claims 1 to 5, wherein the activated carbon has a specific surface area of 600 ^m2 /g or more. The method for producing activated carbon according to any one of claims 1 to 6, wherein the composition of the introduced gas is not changed in the activation step. The method for producing activated carbon according to any one of claims 1 to 7, wherein the introduced gas has a flow rate of 1.5 L/min or more at 0°C and 1 atm per 1 g of the activated carbon precursor. The method for producing activated carbon according to any one of claims 1 to 8, wherein the activation temperature in the activation step is 800 to 1000°C. The method for producing activated carbon according to any one of claims 1 to 9, wherein the content of the metal component in the activated carbon precursor is 0.05 to 1.0% by mass. The method for producing activated carbon according to any one of claims 1 to 10, wherein the activated carbon precursor is infusible pitch. The activated carbon according to any one of claims 1 to 11, wherein the ratio of the pore volume C having a diameter of 2.0 nm or less to the total pore volume A ({pore volume C/pore volume A} × 100) is 85% or more. The method for producing activated carbon according to any one of items 1 to 3. The method for producing activated carbon according to any one of claims 1 to 12, wherein the activated carbon has a pore volume B of 0.25 cc/g or more with a diameter of 1.0 nm or less.

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