Activated carbon

Abstract

A problem of the present invention is to provide activated carbon with high mechanical strength and outstanding trihalomethane filtration ability.　Activated carbon in which a pore volume A of pore widths in the range of 1.0 nm or less, from among pore volumes calculated using the QSDFT method from a nitrogen desorption isotherm, is 0.23 cc / g or more and 0.25 cc / g or less, a pore volume B of pore widths in the range of 1.5 nm or more and 2.5 nm or less, from among pore volumes calculated using the QSDFT method from the nitrogen desorption isotherm, is more than 0.12 cc / g and 0.19 cc / g or less, and the specific surface area is ​​1000 m2 / g or more and 1200 m2 / g or less.

Description

[Technical Field]

[0001] This invention relates to activated carbon having high mechanical strength and excellent trihalomethane filtration capacity. [Background technology]

[0002] Traditionally, chlorine has been added to tap water and other drinking water for sterilization purposes. However, chlorine in tap water reacts with organic matter to produce organic halogen compounds. For example, it is known that when humic substances, which are natural organic matter, react with chlorine in tap water, they produce trihalomethanes such as chloroform, which are carcinogenic substances. Therefore, in recent years, activated carbon with excellent filtration capabilities for trihalomethanes contained in tap water has been proposed.

[0003] For example, Patent Document 1 reports activated carbon with excellent trihalomethane filtration capacity, wherein the pore volume of pores with a diameter of 1.0 nm or less, calculated by the QSDFT method, is 0.3 cc / g or more, and the pore volume of pores with a diameter of 3.0 nm or more and 3.5 nm or less, calculated by the QSDFT method, is 0.009 cc / g or more. The activated carbon described in Patent Document 1 can exhibit excellent trihalomethane filtration capacity even in water treatment at high empty column velocity (SV), and has high utility. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2019 / 244903 Pamphlet [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In order to further improve the functionality of activated carbon, the present inventors conducted studies and found that the activated carbon described in Patent Document 1 has room for further improvement in terms of mechanical strength.

[0006] Therefore, the main object of the present invention is to provide an activated carbon having high mechanical strength and excellent trichloromethane filtration ability.

Means for Solving the Problems

[0007] The present inventors considered that in order to further improve the mechanical strength of the activated carbon described in Patent Document 1, it is necessary to reduce the pore volume A of pores having a pore diameter in the range of 1.0 nm or less. That is, it was considered that the activated carbon described in Patent Document 1, in which the pore volume A of pores having a pore diameter in the range of 1.0 nm or less is 0.3 cc / g or more, is an obstacle to further improving the mechanical strength. However, trichloromethane is considered to be easily adsorbed into pores having a pore diameter in the range of 1.0 nm or less. Simply reducing the pore volume A of such pores would lead to a decrease in the trichloromethane filtration ability, and it would be impossible to achieve both high mechanical strength and excellent trichloromethane filtration ability.

[0008] Therefore, the present inventors conducted further studies and found that by controlling the pore diameter, pore volume, and specific surface area of the activated carbon, it is possible to achieve both high mechanical strength and excellent trichloromethane filtration ability. Specifically, the present inventors found that (1) among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume A of pores having a pore diameter in the range of 1.0 nm or less is 0.230 cc / g or more and 0.250 cc / g or less, (2) among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume B of pores having a pore diameter in the range of 1.5 nm or more and 2.5 nm or less exceeds 0.12 cc / g and is 0.19 cc / g or less, and (3) the specific surface area is 1000 m 2 / g or more and 1200 m 2 / g or less, the activated carbon can have high mechanical strength and excellent trichloromethane filtration ability. The present invention was completed by conducting further studies based on such findings.

[0009] That is, the present invention provides an invention in the following aspects. Item 1. Among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume A of pores with a pore diameter in the range of 1.0 nm or less is 0.230 cc / g or more and 0.250 cc / g or less, Among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, the pore volume B of pores with a pore diameter in the range of 1.5 nm or more and 2.5 nm or less exceeds 0.120 cc / g and is 0.190 cc / g or less, The specific surface area is 1000 m 2 / g or more and 1200 m 2 / g or less, activated carbon. Item 2. The activated carbon according to Item 1, which is fibrous activated carbon. Item 3. The activated carbon according to Item 1 or 2, having a chloroform filtration capacity of 40 L / g or more in the water passing treatment at an empty tower velocity of 3000 h -1 . <Measurement method of chloroform filtration capacity in water passing treatment at an empty tower velocity of 3000 h -1 > Pulverize 3.0 g of dried activated carbon and fill it into a glass column (diameter 25 mm) to prepare an activated carbon column (the filling height of the activated carbon is 41 mm). Prepare test raw water with a chloroform concentration of 60 ± 12 ppb, control the water temperature at 20°C ± 1°C, and pass water through the activated carbon column at an empty tower velocity of 3000 h -1 . Measure the chloroform concentrations of the test raw water and the filtered water by the headspace method using a non-radiation source type electron capture detector, and obtain the water flow rate (L / g) at the time when the chloroform removal rate reaches 80% as the chloroform filtration capacity. Item 4. The activated carbon according to Item 2, having a tensile strength of 0.15 GPa or more measured in accordance with "7.3.2 Tensile Strength" of "Test Methods for Fibrous Activated Carbon" of JIS K 1477:2007. Item 5. A method for producing the activated carbon according to any one of Items 1 to 4, including a step of activating an activated carbon precursor containing 0.1 to 1.0% by mass of yttrium in an atmosphere with a CO2 concentration of 90% by volume or more at a temperature of 925 to 940°C. Item 6. A water filter containing activated carbon as described in any of Items 1-4. Item 7. A method for filtering water using activated carbon as described in any of Items 1 to 4. [Effects of the Invention]

[0010] According to the activated carbon of the present invention, by satisfying predetermined ranges for pore diameter, pore volume, and specific surface area, the activated carbon can possess high mechanical strength and excellent trihalomethane filtration capacity. In particular, the activated carbon of the present invention can exhibit excellent trihalomethane filtration capacity even in water treatment at high empty-stack velocities, making it suitable for applications such as removing trihalomethanes from tap water. [Brief explanation of the drawing]

[0011] [Figure 1] This graph shows the pore size distribution calculated by the QSDFT method from the nitrogen desorption isotherm of the activated carbon in Example 1. [Figure 2] This graph shows the pore size distribution calculated by the QSDFT method from the nitrogen desorption isotherm of the activated carbon in Example 2. [Figure 3] This graph shows the pore size distribution calculated by the QSDFT method from the nitrogen desorption isotherm of the activated carbon in Example 3. [Figure 4] This graph shows the pore size distribution calculated by the QSDFT method from the nitrogen desorption isotherm of the activated carbon of Comparative Example 1. [Figure 5] This graph shows the pore size distribution calculated by the QSDFT method from the nitrogen desorption isotherm of the activated carbon in Comparative Example 2. [Figure 6] This graph shows the pore size distribution calculated by the QSDFT method from the nitrogen desorption isotherm of the activated carbon in Comparative Example 3. [Modes for carrying out the invention]

[0012] The activated carbon of the present invention has a pore volume A with a pore diameter in the range of 1.0 nm or less of 0.230 cc / g or more and 0.250 cc / g or less, and a pore volume B with a pore diameter in the range of 1.5 nm or more and 2.5 nm or less, exceeding 0.12 cc / g and 0.19 cc / g or less, among the pore volumes calculated by the QSDFT method from the nitrogen desorption isotherm, and a specific surface area of 1000 m 2 / g or more and 1200 m 2 / g or less. Hereinafter, the activated carbon of the present invention will be described in detail.

[0013] [Pore diameter and pore volume] In the present invention, the pore diameter and pore volume of the activated carbon are values calculated by the QSDFT method (quenched solid density functional theory method) from the nitrogen desorption isotherm (relative pressure 0.02 to 0.995) measured at a temperature of 77K. The QSDFT method is an analysis method for pore diameter analysis of geometrically and chemically irregular microporous and mesoporous carbons, capable of calculating the pore diameter distribution from about 0.5 nm to about 40 nm. In the QSDFT method, the influence due to the roughness and non-uniformity of the pore surface is clearly considered, so it is a method with significantly improved accuracy in pore diameter distribution analysis. In the present invention, for the measurement of the nitrogen desorption isotherm, a gas adsorption amount measuring device such as "AUTOSORB-1-MP" manufactured by Quantachrome may be used, and for the pore diameter distribution analysis by the QSDFT method, N2at 77K on carbon[slit pore,QSDFT equilibrium model] may be applied as a calculation model.

[0014] The activated carbon of the present invention has a pore volume A in the range of pore diameters of 1.0 nm or less, calculated from nitrogen desorption isotherms by the QSDFT method, which is between 0.230 cc / g and 0.250 cc / g. By setting the pore volume A to 0.250 cc / g or less, the activated carbon can be given high mechanical strength. Furthermore, by setting the pore volume A to 0.230 cc / g or more, the activated carbon can be given excellent trihalomethane filtration capacity, especially excellent trihalomethane filtration capacity even under high tower velocity. From the viewpoint of making it easier to achieve both high mechanical strength and excellent trihalomethane filtration capacity, the pore volume A is preferably between 0.230 cc / g and 0.245 cc / g, more preferably between 0.230 cc / g and 0.240 cc / g, and even more preferably between 0.235 cc / g and 0.240 cc / g.

[0015] The activated carbon of the present invention has a pore volume B in the range of pore diameters between 1.5 nm and 2.5 nm, calculated by the QSDFT method from nitrogen desorption isotherms, which is greater than 0.120 cc / g and less than or equal to 0.190 cc / g. By making the pore volume B greater than 0.120 cc / g, it is possible to provide excellent trihalomethane filtration capacity, especially excellent trihalomethane filtration capacity even under high tower velocity. Furthermore, by making the pore volume B 0.19 cc / g or less, it is possible to easily satisfy the aforementioned pore volume A in the range of 0.230 cc / g or more. According to the inventors' findings, pores with a pore diameter in the range of 1.5 nm to 2.5 nm are thought to have the function of diffusing trihalomethanes into the pores, while being more adsorbent of trihalomethanes compared to pores with a pore diameter in the range of 3.0 nm to 3.5 nm. Therefore, it is believed that the activated carbon of the present invention can exhibit excellent trihalomethane adsorption performance even when the pore volume A of pores with a diameter of 1.0 nm or less, which is responsible for trihalomethane adsorption performance, is reduced to 0.250 cc / g or less.

[0016] In the activated carbon of the present invention, from the viewpoint of providing excellent trihalomethane filtration capacity, particularly excellent trihalomethane filtration capacity even under high tower velocity, the pore volume B is preferably 0.121 cc / g or more and 0.180 cc / g or less, more preferably 0.145 cc / g or more and 0.175 cc / g or less, even more preferably 0.150 cc / g or more and 0.170 cc / g or less, and particularly preferably 0.153 cc / g or more and 0.169 cc / g or less.

[0017] In the activated carbon of the present invention, the pore volume of pores with a diameter of 0.65 nm or less, among the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, is not particularly limited as long as the pore volumes A and B satisfy the range described above. For example, it can be 0.060 cc / g or more and 0.090 cc / g or less, preferably 0.060 cc / g or more and 0.077 cc / g or less, and more preferably 0.069 cc / g or more and 0.077 cc / g or less. By satisfying such a range, it becomes easier to achieve a more favorable balance between high mechanical strength and excellent trihalomethane filtration capacity.

[0018] In the activated carbon of the present invention, the pore volume of pores with a diameter of 0.8 nm or less, among the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, is not particularly limited as long as the pore volumes A and B satisfy the range described above. For example, it can be 0.140 cc / g or more and 0.150 cc / g or less, preferably 0.144 cc / g or more and 0.150 cc / g or less. By satisfying such a range, it becomes easier to achieve a more favorable balance between high mechanical strength and excellent trihalomethane filtration capacity.

[0019] In the activated carbon of the present invention, the pore volume of pores with a diameter of 1.5 nm or less, among the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, is not particularly limited as long as the pore volumes A and B satisfy the range described above. For example, it can be 0.300 cc / g or more and 0.400 cc / g or less, preferably 0.300 cc / g or more and 0.350 cc / g or less. By satisfying such a range, it becomes easier to achieve a more favorable balance between high mechanical strength and excellent trihalomethane filtration capacity.

[0020] In the activated carbon of the present invention, the pore volume of pores with a diameter of 2.0 nm or less, among the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, is not particularly limited as long as the pore volumes A and B satisfy the range described above. For example, it can be 0.350 cc / g or more and 0.450 cc / g or less, preferably 0.350 cc / g or more and 0.425 cc / g or less, and more preferably 0.380 cc / g or more and 0.425 cc / g or less. By satisfying such a range, it becomes easier to achieve a more favorable balance between high mechanical strength and excellent trihalomethane filtration capacity.

[0021] In the activated carbon of the present invention, the pore volume of pores with a diameter of 2.5 nm or more, among the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, is not particularly limited as long as the pore volumes A and B satisfy the range described above, but for example, it can be 0.200 cc / g or less, preferably 0.030 cc / g or more and 0.180 cc / g or less, and more preferably 0.055 cc / g or more and 0.160 cc / g or less.

[0022] In the activated carbon of the present invention, the pore volume of pores with a diameter of 3.5 nm or more, among the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, is not particularly limited as long as the pore volumes A and B satisfy the range described above, but for example, it can be 0.010 cc / g or less, preferably 0.005 cc / g or less. By satisfying such a range, the filtration capacity of trihalomethanes can be further improved.

[0023] In the activated carbon of the present invention, the total pore volume calculated by the QSDFT method from the nitrogen desorption isotherm is not particularly limited, as long as the pore volumes A and B satisfy the range described above. For example, it can be 0.400 cc / g or more and 0.800 cc / g or less, preferably 0.450 cc / g or more and 0.700 cc / g or less, and more preferably 0.500 cc / g or more and 0.670 cc / g or less. By satisfying such a range, it becomes easier to achieve a more favorable balance between high mechanical strength and excellent trihalomethane filtration capacity.

[0024] [Specific surface area] In the activated carbon of the present invention, the specific surface area is 1000 m². 2 / g or more 1200m 2 It is less than / g. Specific surface area of ​​1000m² 2 By setting the specific surface area to 1200 m² or higher, it is possible to achieve excellent trihalomethane filtration capacity, especially under high tower velocity conditions. 2 By setting it to less than / g, it becomes easier to satisfy the aforementioned pore volume A within the range of 0.230 cc / g or more. From the viewpoint of further improving the trihalomethane filtration capacity, especially the trihalomethane filtration capacity under high tower velocity, the specific surface area of ​​the activated carbon of the present invention is preferably 1000 m 2 / g or more 1180m 2 / g or less, more preferably 1050m 2 / g or more 1180m 2 / g or less, more preferably 1080m 2 / g or more 1160m 2 Examples include values ​​of less than or equal to / g. In this invention, the specific surface area of ​​the activated carbon is a value obtained by the BET method (single-point method with a relative pressure of 0.1 as the measurement point) using nitrogen as the adsorbed substance.

[0025] [Derived ingredients] The raw materials from which the activated carbon of the present invention is derived (main raw materials for the activated carbon precursor) are not particularly limited, but examples include plant-based carbonaceous precursors (e.g., plant-derived materials such as bamboo, wood, sawdust, charcoal, fruit shells such as coconut shells and walnut shells, and fruit seeds), mineral-based carbonaceous precursors (e.g., mineral-derived materials such as peat, lignite, brown coal, bituminous coal, anthracite, coke, and coal tar), infusible or carbonized organic materials, and infusible resins such as phenolic resins. Specifically, examples of the organic materials include polyacrylonitrile, pitch, polyvinyl alcohol, and cellulose. Among these, the activated carbon of the present invention is preferably derived from pitch, and more preferably from coal pitch.

[0026] [Contained metal species] In one embodiment of the activated carbon of the present invention, yttrium is contained in the activated carbon. As described later, a preferred method for producing the activated carbon of the present invention includes a step of activating an activated carbon precursor containing a yttrium compound, and the activated carbon obtained by this method contains yttrium derived from the yttrium compound in the activated carbon precursor. The yttrium contained in one embodiment of the activated carbon of the present invention may be in the form of elemental yttrium, a yttrium compound, or a mixture thereof. In one embodiment of the activated carbon of the present invention, the yttrium content may be, for example, 0.001 to 1.0% by mass, preferably 0.01 to 0.8% by mass, and more preferably 0.4 to 0.6% by mass. The yttrium content in the activated carbon can be determined by measuring the yttrium element content using an energy-dispersive X-ray fluorescence analyzer. Furthermore, if the activated carbon of the present invention contains yttrium, the yttrium content can be reduced by washing. Reducing the yttrium content by washing does not affect the mechanical strength and trihalomethane filtration capacity of the activated carbon of the present invention.

[0027] Furthermore, in one embodiment of the activated carbon of the present invention, the activated carbon is substantially free of iron (elemental iron and / or iron compounds). Here, "substantially free of iron" means that when the activated carbon is ashed, the ash is dissolved in acid, and the iron content measured by an ICP emission spectrometer is below the detection limit.

[0028] [form] The form of the activated carbon of the present invention is not particularly limited, but examples include fibrous, granular, and powder forms. From the viewpoint of processability when processed into a filter and the adsorption rate of trihalomethanes when used in a water purifier, fibrous activated carbon is preferred.

[0029] When the activated carbon of the present invention is fibrous, the average fiber diameter can be, for example, 30 μm or less, preferably about 5 to 20 μm, more preferably about 10 to 20 μm, and even more preferably about 12 to 16 μm. In this invention, the average fiber diameter of fibrous activated carbon is determined by observing a side view of a single fibrous activated carbon test piece with an optical microscope and capturing the image using a microscope camera system attached to the microscope. The captured image is imported into image analysis software, and the width at any position along the length of the test piece is measured. This is done for 50 fibrous activated carbons, and the average value of the widths of these 50 is taken as the average fiber diameter.

[0030] When the activated carbon of the present invention is in granular or powder form, the particle size can be, for example, 0.01 to 5 mm in terms of the cumulative volume percentage D50 measured by the laser diffraction / scattering method.

[0031] [Trihalomethane filtration capacity] The activated carbon of the present invention can have excellent trihalomethane filtration capacity, particularly excellent trihalomethane filtration capacity even at high tower speeds, by satisfying predetermined ranges for pore volume A, pore volume B, and specific surface area as described above.

[0032] As an example of the trihalomethane filtration capacity that the activated carbon of the present invention may possess, the following is shown for an empty tower velocity of 3000 h. -1The chloroform filtration capacity during the water treatment is 40 L / g or more, preferably 40 to 90 L / g, more preferably 40 to 60 L / g, and even more preferably 42 to 45 L / g. <Sky tower speed 3000h -1 Method for measuring chloroform filtration capacity in water treatment > 3.0 g of dried activated carbon was beaten and packed into a glass column (25 mm in diameter) to prepare an activated carbon column (with a packing height of 41 mm). Test raw water with a chloroform concentration of 60 ± 12 ppb was prepared, the water temperature was maintained at 20 °C ± 1 °C, and the empty column velocity was 3000 h. -1 Water is then passed through the activated carbon column. The chloroform concentrations of the test raw water and filtered water are measured using the headspace method with a non-radiation source electron capture detector, and the water flow rate (L / g) at which the chloroform removal rate reaches 80% is determined as the chloroform filtration capacity. The chloroform removal rate (%) is calculated according to the following formula. The water flow rate at which the chloroform removal rate reaches 80% is the total amount of filtrate that has flowed out of the activated carbon column and been recovered by the time the chloroform removal rate drops to 80%. Details of the method for measuring the chloroform filtration capacity are described in the Examples section.

number

[0033] [Mechanical strength] The activated carbon of the present invention can possess high mechanical strength by satisfying predetermined ranges for pore volume A, pore volume B, and specific surface area as described above.

[0034] As an example of the mechanical strength that the activated carbon of the present invention may possess when it is fibrous activated carbon, a tensile strength of 0.15 GPa or higher, preferably 0.15 to 0.40 GPa, and more preferably 0.16 to 0.25 GPa can be mentioned. In the present invention, the tensile strength of the fibrous activated carbon is a value measured in accordance with "7.3.2 Tensile Strength" of the Japanese Industrial Standard JIS K 1477:2007 "Test Method for Fibrous Activated Carbon". The specific measurement conditions are as described in the Examples section.

[0035] [Application] The uses of the activated carbon of the present invention are not particularly limited, but it is preferably used for water purification. In particular, since the activated carbon of the present invention has excellent trihalomethane filtering ability, it is suitably used as a water purification filter for removing trihalomethanes from liquids containing trihalomethanes or liquids that may contain trihalomethanes.

[0036] When the activated carbon of the present invention is used as a water filter, it may be molded into a desired shape as needed. For example, when used as a water filter for a water purifier, it is preferably cylindrical, and a cap may be attached to the top of the cylindrical part as needed, and the surface may be covered with nonwoven fabric. Alternatively, when the activated carbon of the present invention is used as a water filter, it can be provided as a cartridge by filling a housing with the activated carbon, either as is or molded into a desired shape.

[0037] The trihalomethane to be removed by the activated carbon of the present invention may be at least one of chloroform, bromodichloromethane, dibromochloromethane, and bromoform, but chloroform is preferred.

[0038] Furthermore, the liquid to be treated by the activated carbon of the present invention may be any liquid containing trihalomethanes or a liquid that may contain trihalomethanes, but examples include tap water, industrial water, and preferably tap water.

[0039] Furthermore, since the activated carbon of the present invention possesses excellent trihalomethane filtration capacity even at high tower speeds, it can be suitably used as a water purification filter for water treatment (filtration) at high tower speeds. Needless to say, it can also be used as a water purification filter for water treatment at low tower speeds, not just high tower speeds. An example of the tower speed during water treatment applicable to the activated carbon of the present invention is 500 h. -1 Preferably 1000 to 4000 hours -1Examples include: When the activated carbon of the present invention is used for water treatment at high tower speeds, the applicable high tower speed is preferably 2000 to 4000 h. -1 , more 2000~3500h -1 These are some examples.

[0040] [Manufacturing method] The method for producing activated carbon of the present invention is not particularly limited, as long as it yields activated carbon that satisfies the aforementioned pore volume A, pore volume B, and specific surface area within predetermined ranges. However, a preferred example is a production method that includes a step of activating an activated carbon precursor containing 0.1 to 1.0 mass% of yttrium in an atmosphere with a CO2 concentration of 90 volume% or higher at a temperature of 925 to 940°C. Hereinafter, this production method will be referred to as "the method for producing activated carbon of the present invention" and will be described in detail.

[0041] In the method for producing activated carbon of the present invention, an activated carbon precursor containing 0.1 to 1.0% by mass of yttrium is activated at 925 to 940°C using an activation gas containing 90% or more by volume of CO2, which reacts more slowly than water vapor, thereby making it possible to obtain activated carbon that satisfies the aforementioned pore volume A, pore volume B, and specific surface area within a predetermined range.

[0042] In the method for producing activated carbon of the present invention, the main raw material for the activated carbon precursor is not particularly limited, but examples include infusible or carbonized organic materials, infusible resins such as phenolic resins, etc. Examples of the organic material include polyacrylonitrile, pitch, polyvinyl alcohol, cellulose, etc. Among these main raw materials, pitch is preferred in terms of the theoretical carbonization yield during carbonization, and coal pitch is particularly preferred among pitches.

[0043] The yttrium contained in the activated carbon precursor may be pure yttrium, a yttrium compound, or a mixture thereof, but a yttrium compound is preferred.

[0044] Examples of yttrium compounds include inorganic yttrium compounds such as yttrium oxides, yttrium hydroxides, yttrium halides, and yttrium sulfates; organic acid salts of yttrium such as yttrium acetates; and organic yttrium compounds. Among these yttrium compounds, organic yttrium compounds are preferred from the viewpoint of improving the dispersibility of the yttrium compound in the activated carbon precursor and making it easier to satisfy the aforementioned pore volume A, pore volume B, and specific surface area within a suitable range for the resulting activated carbon. A preferred example of an organic yttrium compound is a yttrium complex having a β-diketone type compound as a ligand. Examples of β-diketone type compounds include those having the structures shown in the following formulas (1) to (3).

[0045] [ka]

[0046] In the above equation (1), R 12 and R 13 R is the same or different alkyl group having 1 to 22 carbon atoms or an alkenyl group having 1 to 22 carbon atoms, preferably an alkyl group having 1 to 11 carbon atoms or an alkenyl group having 1 to 11 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and even more preferably a methyl group. In formula (1), R 11 This represents a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or an alkenyl group having 1 to 22 carbon atoms, preferably a hydrogen atom, an alkyl group having 1 to 11 carbon atoms, or an alkenyl group having 1 to 11 carbon atoms, more preferably a hydrogen atom.

[0047] In equation (2) above, R 21 R represents a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or an alkenyl group having 1 to 22 carbon atoms, preferably a hydrogen atom, an alkyl group having 1 to 11 carbon atoms, or an alkenyl group having 1 to 11 carbon atoms, more preferably a hydrogen atom. In formula (2), R 22R represents a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or an alkenyl group having 1 to 22 carbon atoms, preferably a hydrogen atom, an alkyl group having 1 to 11 carbon atoms, or an alkenyl group having 1 to 11 carbon atoms, more preferably a hydrogen atom. In formula (2), R 23 This represents an alkyl group having 1 to 22 carbon atoms or an alkenyl group having 1 to 22 carbon atoms, preferably an alkyl group having 1 to 11 carbon atoms or an alkenyl group having 1 to 11 carbon atoms, more preferably an alkyl group having 1 to 8 carbon atoms, and even more preferably a methyl group.

[0048] In equation (3) above, R 31 and R 33 R represents, either the same or different, a hydrogen atom, a C1-C22 alkyl group, or a C1-C22 alkenyl group, preferably a hydrogen atom, a C1-C11 alkyl group, or a C1-C11 alkenyl group, more preferably a hydrogen atom. In formula (3), R 32 This represents a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or an alkenyl group having 1 to 22 carbon atoms, preferably a hydrogen atom, an alkyl group having 1 to 11 carbon atoms, or an alkenyl group having 1 to 11 carbon atoms, more preferably a hydrogen atom.

[0049] Among yttrium complexes having a β-diketone compound as a ligand, preferably a yttrium complex having a β-diketone compound as shown in formula (1), more preferably trisacetylacetonatoyttrium[acetylacetone(R in formula (1)] 11 and R 13 is a methyl group, R 12 Examples include yttrium complexes in which three molecules (compounds in which hydrogen atoms are present) are coordinated.

[0050] In the method for producing activated carbon of the present invention, the yttrium content in the activated carbon precursor may be 0.1 to 1.0% by mass, but is preferably 0.15 to 1.0% by mass, more preferably 0.15 to 0.5% by mass, and even more preferably 0.20 to 0.25% by mass. The yttrium content in the activated carbon precursor is the amount of yttrium elemental equivalent measured by an energy-dispersive X-ray fluorescence spectrometer.

[0051] In the manufacturing method of the present invention, the CO2 concentration of the activation atmosphere may be 90% by volume or higher, but preferably 95% by volume or higher, and more preferably 99% by volume or higher. As mentioned above, when CO2 is used as the activation gas, the reaction proceeds slowly, so the higher the CO2 concentration, the easier it becomes to adjust the pore size distribution, and the easier it becomes to obtain the activated carbon of the present invention.

[0052] In the activation atmosphere, other components besides CO2 include N2, O2, H2, H2O, and CO.

[0053] In the method for producing activated carbon of the present invention, the activation atmosphere temperature may be 925 to 940°C, but preferably 928 to 938°C, and more preferably 930 to 935°C. By using an activated carbon precursor containing 0.1 to 1.0 mass% of yttrium, and setting the activation temperature within the above range while maintaining an atmosphere with a CO2 concentration of 90 volume% or higher, it becomes possible to obtain activated carbon that satisfies the predetermined ranges for pore volume A, pore volume B, and specific surface area.

[0054] Furthermore, the activation time can be adjusted according to the main raw material of the activated carbon precursor, the content of the yttrium compound, the CO2 concentration in the activation gas, etc., to achieve a predetermined pore size distribution and specific surface area. For example, if pitch with a softening point of 275°C to 288°C is used as the main raw material of the activated carbon precursor, and the yttrium compound content of the activated carbon precursor is 0.1 to 1.0 parts by mass, and the CO2 concentration is 100% by volume, the activation atmosphere temperature can be set to 925 to 940°C and the activation time to 30 to 50 minutes.

[0055] The activated carbon obtained after activation may be subjected to washing treatment using an acid such as sulfuric acid, if necessary. Washing treatment can reduce the yttrium content in the activated carbon without adversely affecting its mechanical strength or trihalomethane filtration capacity. [Examples]

[0056] The present invention will be described in detail below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

[0057] 1. Test Method (1) Yttrium content (mass%) of activated carbon precursor (infusible pitch fibers) The pitch fibers were crushed, and the yttrium content was determined by measuring the proportion of yttrium elements using an energy-dispersive X-ray fluorescence analyzer (NEX DE, manufactured by Rigaku Corporation).

[0058] (2) Iron content (mass%) of activated carbon precursor (infusible pitch fibers) Pitch fibers were subjected to ashing treatment, the ash was dissolved in acid, and the iron content was determined by measuring the iron equivalent percentage using an ICP emission spectrometer (Varian Model 715-ES).

[0059] (3) Yttrium content of activated carbon (mass %) Fibrous activated carbon was pulverized, and the yttrium content was determined by measuring the proportion of yttrium elements using an energy-dispersive X-ray fluorescence analyzer (NEX DE, manufactured by Rigaku Corporation).

[0060] (4) Iron content of activated carbon (mass %) Fibrous activated carbon was subjected to ashing treatment, the ash was dissolved in acid, and the iron content was determined by measuring the percentage of iron elemental equivalent using an ICP emission spectrometer (Varian, model 715-ES).

[0061] (5) Pore volume (cc / g) and specific surface area (m²) 2 / g) Pore ​​properties were measured using Quantachrome's "AUTOSORB-1-MP" from nitrogen adsorption isotherms at 77K (relative pressure 0.02~0.995). Specific surface area was calculated from the measurement point at relative pressure 0.1 using the BET method. The total pore volume and the pore volume in each pore diameter range listed in Table 1 were analyzed by applying the N2at 77K on carbon [slit pore, QSDFT equilibrium model] as a calculation model to the measured nitrogen desorption isotherms to calculate the pore diameter distribution. Specifically, the pore volume in each pore diameter range listed in Table 1 is the reading from the graph showing the pore diameter distribution shown in Figures 1 to 6, or the value calculated from that reading. More specifically, the pore volume for pores with a diameter of 0.65 nm or less is the reading of Cumulative Pore Volume (cc / g) at a pore width of 0.65 nm on the horizontal axis of the pore diameter distribution diagram. Similarly, pore volumes for pore diameters of 0.8 nm or less, pore volume A for pore diameters of 1.0 nm or less, pore volume for pore diameters of 1.5 nm or less, pore volume for pore diameters of 2.0 nm or less, pore volume for pore diameters of 2.5 nm or less, pore volume for pore diameters of 3.0 nm or less, and pore volume for pore diameters of 3.5 nm or less were obtained. Pore volume B for pore diameters between 1.5 nm and 2.5 nm was calculated by subtracting the pore volume for pore diameters of 1.5 nm or less from the pore volume for pore diameters of 2.5 nm or less. The total pore volume was obtained using the total pore volume obtained by the QSDFT method. The pore volume for pore diameters of 2.0 nm or more was calculated by subtracting the pore volume for pore diameters of 2.0 nm or less from the total pore volume obtained by the QSDFT method. The pore volume for pores with a diameter of 2.5 nm or larger was calculated by subtracting the pore volume for pores with a diameter of 2.5 nm or less from the total pore volume obtained by the QSDFT method. The pore volume for pores with a diameter of 3.5 nm or larger was calculated by subtracting the pore volume for pores with a diameter of 3.5 nm or less from the total pore volume obtained by the QSDFT method. The pore volume for pores with a diameter in the range of 1.0 nm to 1.5 nm was calculated by subtracting the pore volume A for pores with a diameter of 1.0 nm or less from the pore volume for pores with a diameter of 1.5 nm or less. The pore volume for pores with a diameter in the range of 1.0 nm to 2.0 nm was calculated by subtracting the pore volume A for pores with a diameter of 1.0 nm or less from the pore volume for pores with a diameter of 2.0 nm or less.The pore volume for pore diameters between 0.65 nm and 0.8 nm was calculated by subtracting the pore volume for pore diameters of 0.65 nm and below from the pore volume for pore diameters of 0.8 nm and below. The pore volume for pore diameters between 0.65 nm and 1.0 nm was calculated by subtracting the pore volume for pore diameters of 0.65 nm and below from the pore volume A for pore diameters of 1.0 nm and below. The pore volume for pore diameters between 0.8 nm and 1.5 nm was calculated by subtracting the pore volume for pore diameters of 0.8 nm and below from the pore volume for pore diameters of 1.5 nm and below. The pore volume for pore diameters between 2.0 nm and 3.0 nm was calculated by subtracting the pore volume for pore diameters of 2.0 nm and below from the pore volume for pore diameters of 3.0 nm and below.

[0062] (6) Fiber diameter of fibrous activated carbon (μm) A side view of a single fibrous activated carbon specimen was observed using an optical microscope (Nikon ECLIPSE E600) at 40x magnification, and the image was captured using a microscope camera system (Moticam Pro 252A, Motic) (512×384) attached to the microscope. The captured images were imported into image analysis software (Image-Pro Plus), and the width at any point along the length of the specimen was measured. This was done for 50 fibrous activated carbon specimens, and the average width of these 50 specimens was defined as the average fiber diameter.

[0063] (7) Chloroform filtration capacity (L / g) After drying fibrous activated carbon in a 105°C dryer for more than 2 hours, 3.0 g was taken, beaten in a mixer, and then packed into a glass column (25 mm in diameter) to prepare an activated carbon column (with a packing height of 41 mm). Based on the method specified in "6.4.4.1 Individual Tests" of JIS S 3201:2019 "Test Methods for Household Water Purifiers," test raw water with a chloroform concentration of 60 ± 12 ppb was prepared, the water temperature was controlled to 20°C ± 1°C, and the empty column velocity was 3000 h. -1Water was passed through an activated carbon column. The chloroform concentrations of the test raw water and filtered water were measured using the headspace method with a non-radiation source electron capture detector (GC7000EN, manufactured by J-Science Lab Co., Ltd.). The test raw water was continuously passed through the column until the chloroform removal rate of the filtered water fell below 80%, and the flow rate (L / g) at the point when the chloroform removal rate reached 80% was defined as the chloroform filtration capacity of the activated carbon. If the flow rate at the point when the chloroform removal rate reached 80% was 40 L / g or more, it can be evaluated as having excellent chloroform filtration capacity. The chloroform removal rate (%) was calculated according to the following formula. Furthermore, the flow rate at the point when the chloroform removal rate reached 80% refers to the total amount of filtrate that flowed out of the activated carbon column and was recovered up to the point when the chloroform removal rate decreased to 80%.

number

[0064] (8) Tensile strength (GPa) of fibrous activated carbon The tensile strength was measured in accordance with JIS K 1477:2007 "Test Method for Fibrous Activated Carbon," section 7.3.2, using a tensile testing machine (product name SIMADZU EZ-SX) manufactured by Shimadzu Corporation. Specifically, a test specimen was prepared by fixing both ends of a single fibrous activated carbon to a test base. The test specimen was mounted on the tensile testing machine, and the test base of the specimen was cut to perform a tensile test on the fibrous activated carbon. The tensile test was performed with a specimen length of 10.0 ± 0.2 mm and a tensile speed of 1 mm / min. The force (N) applied when the fibrous activated carbon was cut was calculated based on the average fiber diameter and the fiber cross-sectional area (mm²) as described above. 2 Divide by ( ) and convert to GPa (1 GPa = 1000 N / mm²) 2 The tensile strength was calculated by ( ). If the tensile strength of the fibrous activated carbon is 0.15 GPa or higher, it can be evaluated as having high mechanical strength.

[0065] 2. Manufacturing and evaluation results of fibrous activated carbon Example 1 As an organic material, 1.0 part by mass of trisacetylacetonatoyttrium (CAS number: 15554-47-9) was mixed with 100 parts by mass of granular coal pitch with a softening point of 280°C. This mixture was supplied to a melt extruder, melted and mixed at a melting temperature of 325°C, and spun to obtain pitch fibers. The obtained pitch fibers were subjected to an infusibility treatment by raising the temperature from room temperature in air to 360°C at a rate of 1 to 30°C / min for 70 minutes to obtain an activated carbon precursor, which is an infusible pitch fiber. In this activated carbon precursor, the yttrium content was 0.228% by mass, and the iron content was 0% by mass.

[0066] The obtained activated carbon precursor was activated by continuously introducing a CO2 gas with a concentration of 100% by volume into an activation furnace and heat-treating it at an ambient temperature of 935°C for 40 minutes to obtain fibrous activated carbon.

[0067] Table 1 shows the results of measuring the metal content, pore volume, specific surface area, fiber diameter of fibrous activated carbon, chloroform filtration capacity, and tensile strength of the obtained activated carbon. The obtained activated carbon had a pore volume A of 0.238 cc / g for pore diameters in the range of 1.0 nm or less, a pore volume B of 0.169 cc / g for pore diameters in the range of 1.5 nm to 2.5 nm, and a specific surface area of ​​1151 m². 2 The activated carbon contained 0.57% yttrium per gram, 0% iron per gram, and had an average fiber diameter of 14.0 μm. Furthermore, the obtained activated carbon was washed with sulfuric acid. The yttrium content of the activated carbon after washing was 0.038% per gram. In addition, the pore volume, specific surface area, fiber diameter of the fibrous activated carbon, chloroform filtration capacity, and tensile strength of the activated carbon after washing remained unchanged from before washing.

[0068] Example 2 As an organic material, 1.0 part by mass of trisacetylacetonatoyttrium (CAS number: 15554-47-9) was mixed with 100 parts by mass of granular coal pitch with a softening point of 280°C. This mixture was supplied to a melt extruder, melted and mixed at a melting temperature of 325°C, and spun to obtain pitch fibers. The obtained pitch fibers were subjected to an infusibility treatment by raising the temperature from room temperature in air to 360°C at a rate of 1 to 30°C / min for 70 minutes to obtain an activated carbon precursor, which is an infusible pitch fiber. In this activated carbon precursor, the yttrium content was 0.228% by mass. The iron content was 0% by mass.

[0069] The obtained activated carbon precursor was activated by continuously introducing a CO2 gas with a concentration of 100% by volume into an activation furnace and heat-treating it at an ambient temperature of 930°C for 40 minutes to obtain fibrous activated carbon.

[0070] Table 1 shows the results of measuring the metal content, pore volume, specific surface area, fiber diameter of fibrous activated carbon, chloroform filtration capacity, and tensile strength of the obtained activated carbon. The obtained activated carbon had a pore volume A of 0.240 cc / g for pore diameters in the range of 1.0 nm or less, a pore volume B of 0.153 cc / g for pore diameters in the range of 1.5 nm to 2.5 nm, and a specific surface area of ​​1097 m². 2 The activated carbon contained 0.53% yttrium per gram, 0% iron per gram, and had an average fiber diameter of 14.0 μm. Furthermore, the obtained activated carbon was washed with sulfuric acid. The yttrium content of the activated carbon after washing was 0.038% per gram. In addition, the pore volume, specific surface area, fiber diameter of the fibrous activated carbon, chloroform filtration capacity, and tensile strength of the activated carbon after washing remained unchanged from before washing.

[0071] Example 3 As an organic material, 1.0 part by mass of trisacetylacetonatoyttrium (CAS number: 15554-47-9) was mixed with 100 parts by mass of granular coal pitch with a softening point of 280°C. This mixture was supplied to a melt extruder, melted and mixed at a melting temperature of 325°C, and spun to obtain pitch fibers. The obtained pitch fibers were subjected to an infusibility treatment by raising the temperature from room temperature in air to 360°C at a rate of 1 to 30°C / min for 70 minutes to obtain an activated carbon precursor, which is an infusible pitch fiber. In this activated carbon precursor, the yttrium content was 0.232% by mass. The iron content was 0% by mass.

[0072] The obtained activated carbon precursor was activated by continuously introducing a CO2 gas with a concentration of 100% by volume into an activation furnace and heat-treating it at an ambient temperature of 930°C for 40 minutes to obtain fibrous activated carbon.

[0073] Table 1 shows the results of measuring the metal content, pore volume, specific surface area, fiber diameter of fibrous activated carbon, chloroform filtration capacity, and tensile strength of the obtained activated carbon. The obtained activated carbon had a pore volume A of 0.239 cc / g for pore diameters in the range of 1.0 nm or less, a pore volume B of 0.122 cc / g for pore diameters in the range of 1.5 nm to 2.5 nm, and a specific surface area of ​​1005 m². 2 The activated carbon contained 0.44% by mass of yttrium, 0% by mass of iron, and had an average fiber diameter of 14.6 μm. Furthermore, the obtained activated carbon was washed with sulfuric acid. The yttrium content of the activated carbon after washing was 0.038% by mass. In addition, the pore volume, specific surface area, fiber diameter of the fibrous activated carbon, chloroform filtration capacity, and tensile strength of the activated carbon after washing remained unchanged from before washing.

[0074] Comparative Example 1 As an organic material, 1.3 parts by mass of trisacetylacetonatoyttrium (CAS number: 15554-47-9) was mixed with 100 parts by mass of granular coal pitch with a softening point of 280°C. This mixture was supplied to a melt extruder, melted and mixed at a melting temperature of 325°C, and spun to obtain pitch fibers. The obtained pitch fibers were subjected to an infusibility treatment by raising the temperature from room temperature in air to 370°C at a rate of 1 to 30°C / min for 60 minutes to obtain an activated carbon precursor, which is an infusible pitch fiber. In this activated carbon precursor, the yttrium content was 0.285% by mass. The iron content was 0% by mass.

[0075] The obtained activated carbon precursor was activated by continuously introducing a gas with an H2O concentration of 100% by volume into an activation furnace and heat-treating it at an ambient temperature of 896°C for 32 minutes to obtain fibrous activated carbon.

[0076] Table 1 shows the results of measuring the metal content, pore volume, specific surface area, fiber diameter of fibrous activated carbon, chloroform filtration capacity, and tensile strength of the obtained activated carbon. The obtained activated carbon had a pore volume A of 0.212 cc / g for pore diameters in the range of 1.0 nm or less, a pore volume B of 0.124 cc / g for pore diameters in the range of 1.5 nm to 2.5 nm, and a specific surface area of ​​993 m². 2 The activated carbon contained 0.59% yttrium per gram, 0% iron per gram, and had an average fiber diameter of 17.4 μm. Furthermore, the obtained activated carbon was washed with sulfuric acid. The yttrium content of the activated carbon after washing was 0.038% per gram. In addition, the pore volume, specific surface area, fiber diameter of the fibrous activated carbon, chloroform filtration capacity, and tensile strength of the activated carbon after washing remained unchanged from before washing.

[0077] Comparative Example 2 As an organic material, 1.0 part by mass of trisacetylacetonatoyttrium (CAS number: 15554-47-9) was mixed with 100 parts by mass of granular coal pitch with a softening point of 280°C. This mixture was supplied to a melt extruder, melted and mixed at a melting temperature of 325°C, and spun to obtain pitch fibers. The obtained pitch fibers were subjected to an infusibility treatment by raising the temperature from room temperature in air to 360°C at a rate of 1 to 30°C / min for 70 minutes to obtain an activated carbon precursor, which is an infusible pitch fiber. In this activated carbon precursor, the yttrium content was 0.234% by mass. The iron content was 0% by mass.

[0078] The obtained activated carbon precursor was activated by continuously introducing a CO2 gas with a concentration of 100% by volume into an activation furnace and heat-treating it at an ambient temperature of 915°C for 40 minutes to obtain fibrous activated carbon.

[0079] Table 1 shows the results of measuring the metal content, pore volume, specific surface area, fiber diameter of fibrous activated carbon, chloroform filtration capacity, and tensile strength of the obtained activated carbon. The obtained activated carbon had a pore volume A of 0.239 cc / g for pore diameters in the range of 1.0 nm or less, a pore volume B of 0.112 cc / g for pore diameters in the range of 1.5 nm to 2.5 nm, and a specific surface area of ​​960 m². 2 The activated carbon was found to contain 0.45% by mass of yttrium, 0% by mass of iron, and had an average fiber diameter of 14.0 μm. Furthermore, the obtained activated carbon was washed with sulfuric acid. The yttrium content of the activated carbon after washing was 0.038% by mass. In addition, the pore volume, specific surface area, fiber diameter of the fibrous activated carbon, chloroform filtration capacity, and tensile strength of the activated carbon after washing remained unchanged from before washing.

[0080] Comparative Example 3 As an organic material, 100 parts by mass of granular coal pitch with a softening point of 280°C was mixed with 0.9 parts by mass of tris(2,4-pentanedionato) iron(III) (metal species Fe), and this mixture was supplied to a melting extruder. Pitch fibers were obtained by melting and mixing at a melting temperature of 320°C and spinning. The obtained pitch fibers were subjected to an infusibility treatment by raising the temperature from room temperature in air to 354°C at a rate of 1 to 30°C / min for 54 minutes to obtain an activated carbon precursor, which is an infusible pitch fiber. The iron (Fe) content in this activated carbon precursor was 0.110% by mass.

[0081] The obtained activated carbon precursor was activated by continuously introducing a CO2 gas with a concentration of 100% by volume into an activation furnace and heat-treating it at an ambient temperature of 950°C for 25 minutes to obtain fibrous activated carbon.

[0082] Table 1 shows the results of measuring the metal content, pore volume, specific surface area, fiber diameter of fibrous activated carbon, chloroform filtration capacity, and tensile strength of the obtained activated carbon. The obtained activated carbon had a pore volume A of 0.350 cc / g for pore diameters in the range of 1.0 nm or less, a pore volume B of 0.002 cc / g for pore diameters in the range of 1.5 nm to 2.5 nm, and a specific surface area of ​​988 m². 2 The activated carbon contained 0% yttrium by mass, 0.18% iron by mass, and had an average fiber diameter of 13.9 μm. Furthermore, the obtained activated carbon was washed with sulfuric acid. The iron content of the activated carbon after washing was 0.038% by mass. In addition, the pore volume, specific surface area, fiber diameter of the fibrous activated carbon, chloroform filtration capacity, and tensile strength of the activated carbon after washing remained unchanged from before washing.

[0083] 3. Summary of Evaluation Results Table 1 shows the physical properties of each fibrous activated carbon obtained. Figures 1-6 show the pore size distribution diagrams of each activated carbon calculated by the QSDFT method.

[0084] [Table 1]

[0085] The activated carbons of Examples 1-3 have a tensile strength of 0.15 GPa or higher, possessing high mechanical strength, and furthermore, with an empty tower velocity of 3000 h. -1 The chloroform filtration capacity (water flow rate when the chloroform removal rate reaches 80%) was 40 L / g or more, indicating excellent chloroform filtration capacity under high tower velocity. From the physical properties, tensile strength, and chloroform filtration capacity of the activated carbon in Examples 1-3, it was determined that (1) the pore volume A for pore diameters in the range of 1.0 nm or less, calculated by the SDFT method, was 0.23 cc / g or more and 0.25 cc / g or less, (2) the pore volume B for pore diameters in the range of 1.5 nm or more and 2.5 nm or less, calculated by the QSDFT method, was greater than 0.12 cc / g and 0.19 cc / g or less, and (3) the specific surface area was 1000 m². 2 / g or more 1200m 2 It was found that by satisfying the requirement of less than / g, it is possible to achieve both high mechanical strength and excellent chloroform filtration capacity.

[0086] On the other hand, the activated carbon of Comparative Example 1 had a pore volume A of less than 0.23 cc / g for pore diameters in the range of 1.0 nm or less, and a specific surface area of ​​1000 m². 2 The chloroform filtration capacity at high tower velocities was poor due to the concentration being less than / g.

[0087] The activated carbon of Comparative Example 2 has a pore volume B of less than 0.12 cc / g for pore diameters in the range of 1.5 nm to 2.5 nm, and furthermore, a specific surface area of ​​1000 m². 2 The chloroform filtration capacity at high tower velocities was poor due to the concentration being less than / g.

[0088] The activated carbon in Comparative Example 3 exhibited inferior mechanical strength due to the pore volume A in the pore diameter range of 1.0 nm or less exceeding 0.25 cc / g.

Claims

1. Of the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, the pore volume A for pores with a diameter of 1.0 nm or less is between 0.230 cc / g and 0.245 cc / g. Of the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, the pore volume B for pores with a diameter in the range of 1.5 nm to 2.5 nm is greater than 0.120 cc / g and less than or equal to 0.190 cc / g. Specific surface area of ​​1000 m 2 / g or more 1200m 2 Activated carbon with a weight of less than / g.

2. Among the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, the pore volume A for pore diameters in the range of 1.0 nm or less is 0.230 cc / g or more and 0.250 cc / g or less. Of the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, the pore volume B for pores with a diameter in the range of 1.5 nm to 2.5 nm is greater than 0.120 cc / g and less than or equal to 0.190 cc / g. Of the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, the pore volume for pores with a diameter of 1.5 nm or less is between 0.300 cc / g and 0.340 cc / g. Activated carbon having a specific surface area of ​​1000 m² / g or more and 1200 m² / g or less.

3. The activated carbon according to claim 1 or 2, wherein it is a fibrous activated carbon.

4. The following shows the tower speed of 3000h. -1 The activated carbon according to claim 1 or 2, wherein the chloroform filtration capacity in the water treatment is 40 L / g or more. <Sky tower speed 3000h -1 Method for measuring chloroform filtration capacity in water treatment > 3.0 g of dried activated carbon is beaten and packed into a glass column (25 mm in diameter) to prepare an activated carbon column (with a packing height of 41 mm). Test raw water with a chloroform concentration of 60 ± 12 ppb is prepared, the water temperature is controlled to 20 °C ± 1 °C, and the empty column velocity is 3000 h. -1 Water is then passed through the activated carbon column. The chloroform concentrations of the test raw water and filtered water are measured using the headspace method with a non-radiation source electron capture detector, and the water flow rate (L / g) at which the chloroform removal rate reaches 80% is determined as the chloroform filtration capacity.

5. The activated carbon according to claim 3, wherein the tensile strength measured in accordance with "7.3.2 Tensile Strength" of JIS K 1477:2007 "Test Method for Fibrous Activated Carbon" is 0.15 GPa or more.

6. Among the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, the pore volume A for pore diameters in the range of 1.0 nm or less is 0.230 cc / g or more and 0.250 cc / g or less. Of the pore volumes calculated from nitrogen desorption isotherms by the QSDFT method, the pore volume B for pores with a diameter in the range of 1.5 nm to 2.5 nm is greater than 0.120 cc / g and less than or equal to 0.190 cc / g. A method for producing activated carbon having a specific surface area of ​​1000 m² / g or more and 1200 m² / g or less, An activated carbon precursor containing 0.1 to 1.0% by mass of yttrium is used in CO 2 A method for producing activated carbon, comprising the step of activating it at a temperature of 925 to 940°C in an atmosphere with a concentration of 90% by volume or higher.

7. A water filter comprising activated carbon according to claim 1 or 2.

8. A method for filtering water using activated carbon according to claim 1 or 2.

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