JP6542968B1 - Activated carbon and method for producing the same - Google Patents

Abstract

An object of the present invention is to provide activated carbon having excellent adsorption performance. The activated carbon of the present invention has a BET specific surface area of 650 m 2 / g or more and 1250 m 2 / g or less, a total pore volume of 0.25 cm 3 / g or more, and an average pore diameter of 1.8 nm or more and 4.0 nm or less The chloroform flow rate in the water flow test method is 71 L / g or more. [Selected figure] Figure 3

Description

  The present invention relates to activated carbon and a method for producing the activated carbon.

  Activated carbon is used in a wide range of fields as an adsorbent, an electrode material for capacitors, a catalyst and the like. Moreover, as raw materials of activated carbon, plant materials such as sawdust, wood chips, coconut shells; polymer materials such as phenol resin, polyacrylonitrile, polyimide, and composites thereof (such as paper phenol resin); coal, petroleum, coke And mineral-based materials such as various pitches are used.

  The present inventors have noted that paper phenolic resin can control mesopores and micropores formed by controlling activation conditions, and propose activated carbon having a pore structure suitable for the substance to be adsorbed ( Patent Document 1). Specifically, as an activated carbon that exhibits not only the equilibrium adsorption amount to organic halogen compounds but also excellent adsorption performance even under water flow conditions, the pore volume ratio of pore diameter 2 nm or less and the pore volume ratio of more than 2 nm and 10 nm or less Is disclosed activated carbon.

International Publication No. 2015/152391 pamphlet

  The inventors of the present invention conducted research for the purpose of further improving the adsorption performance of activated carbon even after developing the activated carbon disclosed in Patent Document 1 above.

  The present invention has been made focusing on the above circumstances, and an object thereof is to provide activated carbon having excellent adsorption performance and a method for producing the activated carbon.

[1] The activated carbon of the present invention which has solved the above problems is:
BET specific surface area is 650 m ² / g or more and 1250 m ² / g or less,
Total pore volume is 0.25 cm ³ / g or more,
An average pore diameter of 1.8 nm or more and 4.0 nm or less,
The chloroform water flow rate in the following water flow test method is 71 L / g or more.
Water passing test method: Test water is passed through a column packed with 2.0 g of activated carbon having a particle diameter of 53 to 180 μm, chloroform concentration before and after passing through the column is measured, and total filtered water amount up to the breakthrough point (L) The chloroform water flow rate (L / g) per 1 g is determined to obtain a chloroform water flow rate.
Test water: Distilled water with a chloroform concentration of 0.06 mg / L Space velocity (SV): 500 h ^-1
Chloroform concentration measurement method: Head space gas chromatograph Breakthrough point: When the concentration of chloroform in the column effluent to the column inlet water exceeds 20%

[2] The activated carbon of the present invention is also preferably the activated carbon described in [1], which has a chloroform equilibrium adsorption amount of 4.5 mg / g or more in the following equilibrium test method.
Equilibrium test method: Fill a chloroform solution in a 100 mL Erlenmeyer flask containing a predetermined amount of activated carbon and a stirrer in full water, seal the plug, and stir at 20 ° C for 14 hours, filter out the contents of the Erlenmeyer flask, and filter Determine the equilibrium concentration (mg / L) of chloroform and the chloroform equilibrium adsorption amount (mg / g) per 1 g of activated carbon by the above-mentioned method for measuring the concentration of chloroform and create an adsorption isotherm, and at an equilibrium concentration of 0.06 mg / L The equilibrium adsorption amount (mg / g).
Test solution: Chloroform solution with a concentration of 0.06 mg / L Mass of Erlenmeyer: Measure the mass of Erlenmeyer before and after filling with chloroform solution Particle size of activated carbon: Particle size of 180 μm or less Amount of activated carbon in each test: 0.013 g, 0.026 g , 0.065 g, 0.130 g, 0.260 g
Adsorption isotherm: The equilibrium concentration and the equilibrium adsorption amount are measured for each predetermined amount of the activated carbon, and the adsorption isotherm is created based on the results.

[3] The activated carbon according to the above [1] or [2], which is obtained by subjecting a paper phenol resin laminate having a density of 1.3 g / cm ³ or less to carbonization treatment and then subjecting it to gas activation treatment. .

[4] A preferred method for producing the activated carbon of the present invention is characterized in that the paper phenol resin laminate having a density of 1.3 g / cm ³ or less is carbonized and then subjected to gas activation treatment.

  [5] The method for producing activated carbon according to the above [4], wherein at least one selected from the group consisting of cleaning treatment, drying treatment, pulverization treatment, and heat treatment is performed after the gas activation treatment.

[6] The pore volume of the pore diameter of 1 to 10 μm of the carbide of the paper phenol resin laminate obtained by the carbonization treatment is 0.15 cm ³ / g or more according to the above [4] or [5] Method of producing activated carbon.

  [7] Activated carbon for water purifier obtained by the method according to any one of the above [4] to [6].

  ADVANTAGE OF THE INVENTION According to this invention, the activated carbon which has the characteristic more excellent in adsorption performance than the prior art activated carbon, and the manufacturing method of this activated carbon can be provided.

FIG. 1 is a graph showing the relationship between the mercury intrusion amount of carbide and the pore diameter. FIG. 2 is a graph showing the relationship between the macro pore volume of 1 to 10 μm and the density of the paper phenol resin laminate. FIG. 3 is a graph showing the relationship between the specific surface area of activated carbon and the amount of chloroform water flow in the water flow test. FIG. 4 is a graph showing the relationship between the specific surface area of activated carbon and the chloroform equilibrium adsorption amount in the equilibrium test. FIG. 5 is an electron microscope (SEM) photograph of the activated carbon of the example. FIG. 6 is a graph showing the pore size distribution analyzed by the BJH method from the N ₂ adsorption isotherm of the activated carbon of the example.

  As a result of repeating studies to improve adsorption performance compared to conventional activated carbon, the present inventors have found that the above problems can be solved by improving a paper phenol resin laminate used as a carbon material. Conventionally, an end of a paper phenol resin laminate widely used as a printed circuit board in electronic parts and the like is used as a carbon source of activated carbon. Paper phenolic resin laminates for printed circuit boards are densified to improve various properties such as durability, but surprisingly, paper phenolic resin laminates whose density has been controlled to be lower than conventional are used as carbon raw materials It has been found that the adsorption performance can be improved by activated carbon, and the present invention has been made. Hereinafter, the present invention will be described.

  The activated carbon of the present invention has various substances to be adsorbed in the same manner as known activated carbons, but is preferably chloroform, trifluoromethane, chlorodifluoromethane, bromodichloromethane, trihalomethanes such as dibromochloromethane, tribromomethane, etc., trichloroethane, It has excellent adsorption performance to organic halogen compounds such as trichloroethylene, more preferably trihalomethanes, still more preferably chloroform. In the present invention, the adsorption performance is to have an excellent adsorption performance (hereinafter sometimes referred to as water adsorption performance) to the substance to be adsorbed under preferably water passing conditions, and more preferably, it is more equilibrated. The adsorption amount is also excellent (hereinafter, sometimes referred to as equilibrium adsorption performance). Hereinafter, the adsorption performance refers to the water adsorption performance, but preferably also includes the equilibrium adsorption performance.

The activated carbon of the present invention has a BET specific surface area of 650 m ² / g or more and 1250 m ² / g or less, a pore volume of 0.25 cm ³ / g or more, an average pore diameter of 1.8 nm or more and 4.0 nm or less, Examples The chloroform water flow rate in the water flow test method described has 71 L / g or more.

Water Flow Adsorption Performance The activated carbon of the present invention has superior water flow adsorption performance compared to conventional activated carbon. As described later, the excellent water-flowing adsorption performance of the present invention is derived from a novel carbon source different from the conventional one, but it is possible to identify the physical structure derived from the carbon source even by examining the produced activated carbon Have difficulty. However, since the water adsorption performance is superior to that of conventional activated carbon, there is also a difference in physical structure, and it is clear that it is novel as activated carbon. It regulated by the amount of water. Specifically, the activated carbon of the present invention is 71 L / g or more, preferably 75 L / g or more, more preferably 78 L / g or more as a water flow amount capable of maintaining a removal rate of 80% or more of chloroform based on the water flow test in Examples described later. More preferably, it is 80 L / g or more, still more preferably 85 L / g or more, and most preferably 95 L / g or more.

Equilibrium adsorption performance The activated carbon of the present invention also has superior equilibrium adsorption performance as compared to conventional activated carbon. The excellent equilibrium adsorption performance of the present invention is also derived from a novel carbon raw material, as is the water adsorption performance, but is defined by the chloroform equilibrium adsorption amount as another index indicating a physical structure that is difficult to elucidate. Specifically, the activated carbon of the present invention preferably has a chloroform adsorption amount of 4.5 mg / g or more, more preferably 5.0 mg / g or more, further preferably 5. It is 5 mg / g or more, more preferably 6.0 mg / g or more. The activated carbon of the present invention may satisfy only the above water adsorption performance, but preferably it satisfies both the water adsorption performance and the equilibrium adsorption performance.

BET specific surface area of activated carbon The BET specific surface area of activated carbon is 650 m ² / g or more, preferably 700 m ² / g or more, more preferably 750 m ² / g or more, still more preferably 800 m ² / g to ensure sufficient adsorption amount The above, still more preferably 850 m ² / g or more, most preferably 900 m ² / g or more. On the other hand, the BET specific surface area is 1250 m ² / g or less, more preferably 1200 m, in consideration of the balance between the micropore volume ratio contributing to the improvement of the adsorption amount and the mesopore volume ratio contributing to the diffusion rate improvement. ^{It is 2} or less, more preferably 1150 m ² / g or less, still more preferably 1100 m ² / g or less, and most preferably 1050 m ² / g or less.

Total Pore Volume of Activated Carbon The total pore volume of the activated carbon of the present invention is a pore volume with a pore diameter of 30 nm or less. Sufficient total pore volume in order to ensure the adsorption of 0.25 cm ³ / g or more, preferably 0.30 cm ³ / g or more, more preferably 0.35 cm ³ / g or more, more preferably 0.40 cm ³ / G or more, more preferably 0.45 cm ³ / g or more. The upper limit of the total pore volume is preferably not more than 0.80 cm ³ / g, more preferably 0.75 cm ³ / g or less, more preferably 0.70 cm ³ / g or less, even more preferably 0.60 cm ³ / g or less It is.

Average pore diameter of activated carbon The average pore diameter of activated carbon is 1.80 nm or more, more preferably 1.82 nm or more, still more preferably 1.85 nm or more, from the viewpoint of improving the introduction efficiency of the adsorbate to the inside of activated carbon. Preferably, it is 1.87 nm or more, most preferably 1.90 nm or more. On the other hand, if the average pore size is too large, the packing density may be reduced, so that it is 4.0 nm or less, preferably 3.5 nm or less, more preferably 3.0 nm or less.

Average Particle Size of Activated Carbon The activated carbon of the present invention can be shaped and sized according to the application. When using activated carbon for a water purifier application etc., powdery, granular, or these granulated materials are preferable in consideration of the contact efficiency. The average particle size of the activated carbon (ie, the average particle size of the powdery, granular or granulated product thereof) is preferably 10 μm or more, more preferably 20 μm or more, still more preferably 30 μm or more in consideration of the contact efficiency. Preferably it is 500 micrometers or less, More preferably, it is 300 micrometers or less, More preferably, it is 200 micrometers or less.

  The excellent water flow adsorption performance and equilibrium adsorption performance of the present invention are derived from the predetermined carbon raw material of the present invention. Therefore, even when the BET specific surface area, the total pore volume, and the average pore diameter are within the above ranges, when different carbon raw materials are used, the physical structure is different from that of the activated carbon derived from the predetermined carbon raw material of the present invention. Therefore, the water adsorption performance and equilibrium adsorption performance of the present invention can not be achieved.

The activated carbon of the present invention uses a paper phenol resin laminate having a density of 1.3 g / cm ³ or less (hereinafter sometimes referred to as a low density paper phenol resin laminate) as a carbon material. Specifically, the above-mentioned activated carbon of the present invention is preferably one obtained by subjecting a low density paper phenol resin laminate to carbonization treatment and then performing gas activation treatment. The activated carbon derived from the low density paper phenolic resin laminate is superior to the activated carbon derived from the conventional paper phenolic resin laminate having a density of more than 1.3 g / cm ³ (hereinafter sometimes referred to as high density paper phenolic resin laminated) It has adsorption performance. Therefore, the activated carbon derived from the low density paper phenol resin laminate is considered to have a unique physical structure different from the activated carbon derived from the high density paper phenolic resin laminate. For example, Example 4 and Comparative Example 2 shown in FIG. It is difficult to identify the characteristic of the physical structure of the activated carbon of the invention example to the extent that it can be distinguished from the comparative example from the electron microscope (SEM) picture of the present invention. It is difficult. Further, it is difficult to distinguish the activated carbons of the invention example and the comparative example as shown in FIG. 6 with regard to the pore size distribution of the activated carbon, and it is difficult to identify the characteristics of the activated carbon according to the present invention It is. Therefore, one of the features of the activated carbon of the present invention is that it is preferably activated carbon derived from a specific carbon source. Further, since the activated carbon derived from the conventional high density paper phenol resin laminate can not obtain the excellent adsorption performance of the present invention, it can be distinguished from the conventional activated carbon by defining the degree of the obtained effect.

Paper Phenolic Resin Laminate In the present invention, a low density paper phenolic resin laminate is used as a carbon material. A paper phenol resin laminate is a composite of a paper base (hereinafter referred to as mesopore-forming raw material) in which relatively large pores are easily formed and a phenol resin (hereinafter, micropore-forming raw material) in which relatively small pores are easily formed. It is a body. When the carbides of the low density paper phenol resin laminate are subjected to gas activation treatment, activated carbon having a pore structure contributing to the improvement of the water flow adsorption performance and the equilibrium adsorption performance can be obtained. The density of the paper phenol resin laminate specified in the present invention is lower than the density of the known paper phenol resin laminate, which is a novel material. Then, when the carbide of such a novel paper phenol resin laminate is activated, an activated carbon having a physical structure different from that of the conventional high density paper phenol resin laminate can be obtained.

In the present invention, the low density paper phenol resin laminate is carbonized, but the carbide derived from the low density paper phenol resin laminate has a pore diameter of 1 as shown in FIG. 1 as compared to the carbide derived from the high density paper phenol resin laminate. A pore volume of ̃10 μm is significantly developed. And the carbide derived from the low density paper phenol resin laminate having such a unique pore structure is different from the carbide derived from the high density paper phenol resin laminate from the gas diffusion mode in the carbide at the time of gas activation processing. It is considered to be different. That is, since the carbide derived from the low density paper phenol resin laminate has a low density, it is considered that the gas diffusivity in the inside is high when the gas activation treatment is performed, which affects the formed pores and the pore structure. The activated carbon derived from the low density paper phenol resin laminate is derived from the high density paper phenol resin laminate activated carbonized and activated under the same conditions due to the difference in the formation process of such pores and pore structures. It is considered that the physical structure is different, and the difference appears as a difference in adsorption performance. Such density of paper phenol resin laminate of the present invention expressing a difference 1.30 g / cm ³ or less, preferably 1.25 g / cm ³ or less, more preferably 1.20 g / cm ³ or less, more preferably It is 1.15 g / cm ³ or less. The lower limit of the density of the paper phenol resin laminate is preferably 0.70 g / cm ³ or more, more preferably 0.80 g / cm ³ or more, still more preferably 0.90 g / cm ³ or more, and most preferably 1.00 g / cm ³ or more.

  As the raw material constituting the low density paper phenol resin laminate of the present invention, the same paper as the paper phenol resin laminate used for conventional printed circuit boards and the like, and phenol resin can be used, and other additives and compositions Nor is it limited. Moreover, although the manufacturing method of a low density paper phenol resin laminated body can be manufactured based on the conventional manufacturing method, it is necessary to adjust manufacturing conditions so that it may become the said density. For example, the density of the paper phenol resin laminate can be adjusted to a desired low density by adjusting the pressing pressure when molding and pressing a laminate of paper phenol resin (prepreg) obtained by impregnating a paper substrate with a phenol resin. . In addition, in order to provide the intensity | strength and durability suitable for the printed circuit board etc. for electronic components, the paper phenol resin laminated body is shape | molded by the high press pressure. Therefore, the known paper phenolic resin molded articles are densified, and all exceed the predetermined density of the present invention. On the other hand, the low density paper phenol resin laminate of the present invention can be obtained by reducing the pressing pressure, but the density is low, so the strength and durability are low and it is not suitable for printed circuit board applications. It has the required strength and durability.

Pulverization process 1
In the present invention, the low density paper phenol resin laminate may be ground before carbonization. For example, by refining the low density paper phenol resin laminate, it becomes possible to carry out uniform carbonization treatment and activation treatment in a short time, and therefore, it may be appropriately crushed according to the size of the carbonization furnace. For example, preferably 70% or more, more preferably 75% or more, still more preferably 80% or more of the low density paper phenol resin laminate after grinding, preferably the particle size is 5.0 mm or less, more preferably 4.0 mm or less, More preferably, it is 3.35 mm or less. The lower limit may be appropriately determined in consideration of handling and the like.

Carbonization Treatment Step The carbonization treatment step is a step of carbonizing the low density paper phenol resin laminate to obtain carbides. The carbide obtained by carbonizing the low density paper phenol resin laminate (hereinafter sometimes referred to as low density carbide) has a pore volume of 1 to 10 μm in pore diameter (hereinafter sometimes referred to as macropore volume) Develop significantly. When the low density carbide in which the macro pore volume is developed is subjected to gas activation treatment, the gas diffusion property at the time of gas activation is improved, and the obtained activated carbon has a pore structure which contributes to the improvement of the adsorption performance. Macropore volume of low density carbide exert such an effect, preferably 0.13 cm ³ / g or more, more preferably 0.15 cm ³ / g or more, further preferably 0.20 cm ³ / g or more.

  The ratio of the macro pore volume of 1 to 10 μm to the total macro pore volume of low density carbide is preferably 40% or more, more preferably 45% or more, still more preferably 50% or more, still more preferably 55% or more . The higher the macro pore volume ratio, the better the gas diffusibility during activation processing, and the pore structure contributing to the improvement of the adsorption performance of the obtained activated carbon is obtained, which is preferable.

  It is desirable that carbonization treatment conditions be appropriately adjusted so as to obtain low density carbide having the above-mentioned macro pore volume. The atmosphere at the time of carbonization is preferably an inert gas atmosphere such as nitrogen gas, helium, argon gas and the like. The heat treatment is preferably performed at a temperature and a time at which the low density paper phenol resin laminate does not burn, and the temperature of the carbonization (in-furnace temperature) is preferably 500 ° C. or more, more preferably 550 ° C. or more. Is 1000 ° C. or less, more preferably 950 ° C. or less. The holding time at the carbonization temperature is preferably 1 minute or more, more preferably 5 minutes or more, still more preferably 10 minutes or more, preferably 10 hours or less, more preferably 8 hours or less, more preferably 6 It is less than time.

Gas Activation Treatment Step The gas activation treatment step is a step of gas activation treatment of low density carbide to obtain activated carbon. Activated carbon obtained by gas activation treatment of low density carbide has a unique pore structure excellent in water adsorption performance and equilibrium adsorption performance, although the specific pore structure is unknown.

  The conditions of the gas activation process may be appropriately adjusted so as to obtain the activated carbon. The gas activation treatment is a method of performing activation treatment by heating the carbide to a predetermined temperature and supplying an activation gas. The temperature at which the gas activation treatment is carried out (temperature in the furnace) is preferably 400 ° C. or more, more preferably 500 ° C. or more, still more preferably 600 ° C. or more, preferably 1500 ° C. or less, more preferably 1300 ° C. or less More preferably, it is 1100 ° C. or less. The temperature rising rate at this time is preferably 1 ° C./minute or more, more preferably 2 ° C./minute or more, still more preferably 6 ° C./minute or more, preferably 100 ° C./minute or less, more preferably 50 ° C./minute. Or less, more preferably 25 ° C./minute or less. The heating and holding time is preferably 0.1 hours or more, more preferably 0.25 hours or more, and preferably 10 hours or less, more preferably 7.5 hours or less.

  As the activating gas, water vapor, air, carbon dioxide gas, oxygen, combustion gas, and mixed gas thereof can be used. Hereinafter, although steam is illustrated and described, it is applicable similarly to other activation gas, such as carbon dioxide gas. When steam is supplied, the steam concentration supplied during activation treatment is preferably 40 Vol% or more, more preferably 50 Vol% or more, still more preferably 60 Vol% or more, preferably 100 Vol% or less, more preferably 90 Vol% The content is more preferably 85 vol% or less. When the water vapor concentration to be supplied is in the above range, the formation of pores by the activation reaction becomes better, the activation reaction can proceed more efficiently, and the productivity can be improved.

  As an aspect of supplying water vapor, either an embodiment of supplying water vapor without dilution or an embodiment of supplying water vapor diluted with an inert gas is possible, but in order to allow the activation reaction to proceed efficiently, it is inert The aspect which dilutes and supplies with gas is preferable. When steam is diluted with an inert gas and supplied, the partial pressure of steam in the mixed gas (total pressure 101.3 kPa) is preferably 40 kPa or more, more preferably 50 kPa or more, and still more preferably 70 kPa or more.

Treatment after gas activation treatment Activated carbon after steam activation is subjected to at least one treatment selected from the group consisting of (a) washing treatment, (b) drying treatment, (c) grinding treatment 2 and (d) heat treatment May be (A) The cleaning treatment is performed using activated carbon after steam activation using a known solvent such as water, an acid solution or an alkali solution. By washing the activated carbon, impurities such as ash can be removed. (B) The drying treatment is a step of removing water and the like contained in activated carbon after steam activation or washing. The drying process may be performed by exposing the activated carbon under normal temperature or under heating for a predetermined time. (C) The grinding process 2 is a step of adjusting the particle size of the activated carbon to a size according to the application. The pulverization treatment 2 can be performed using a disk mill, a ball mill, a bead mill or the like, and may be adjusted to a predetermined particle size by classification or the like, if necessary. (D) The heat treatment is a step of subjecting the activated carbon to a high temperature heat treatment under an inert atmosphere. The heat treatment can reduce or remove the amount of acidic functional groups of the activated carbon. The activated carbon derived from the low density paper phenol resin laminate of the present invention can improve its adsorption performance when the amount of acidic functional groups is reduced, so that (d) heat treatment is preferably performed. The inert atmosphere at the time of heat treatment is the same as in the carbonization treatment step. The heat treatment may be performed at any temperature and time that can reduce the acidic functional group, and is preferably 400 ° C. or more, more preferably 600 ° C. or more, and preferably 1300 ° C. or less, more preferably 1200 ° C. or less. The heating and holding time is preferably 0.5 hours or more, more preferably 1 hour or more, still more preferably 1.5 hours or more, preferably 10 hours or less, more preferably 8 hours or less.

  The process after the gas activation process may be performed alone or in combination of two or more processes. When the washing treatment and other treatments are combined, the washing treatment may be performed before or after the grinding treatment, but the washing treatment is preferably performed before the drying treatment or the heat treatment. A preferred combination of multiple treatments is (i) grinding treatment-washing treatment, (ii) washing treatment-grinding treatment, and a more preferred combination is (iii) grinding treatment-washing treatment-drying treatment, (iv) washing treatment-grinding Treatment-drying treatment, and a further preferable combination is (v) grinding treatment-washing treatment-heat treatment, (vi) washing treatment-grinding treatment-heat treatment. Although the heat treatment may be performed after the drying treatment, since the activated carbon can be dried by the heat treatment, the drying treatment may be omitted in consideration of the treatment efficiency. Further, the pulverizing process may be omitted as long as the particle size adjustment and the like are unnecessary in the preferable combinations (iii) to (vi). Moreover, in order to adjust a particle size, classification processing with a sieve etc. may be performed as needed, and classification processing may be performed as a final process after the said processing.

The activated carbon of the present invention can be used as an adsorbent of a substance to be adsorbed which is present in the air or water. In particular, it is suitable for the removal of the following adsorptive substances contained in tap water and industrial wastewater, and is more preferably used as an activated carbon for water purifiers. The form of the water purifier using the activated carbon of the present invention is not particularly limited, and can be applied to various known water purifiers.

  EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples. However, the present invention is of course not limited by the following examples, and appropriate modifications may be made as long as the present invention can be applied to the purpose. Of course, implementation is also possible, and all of them are included in the technical scope of the present invention.

Example 1
Carbon raw material: A press pressure at the time of molding and pressing a laminate of paper phenol resin (prepreg) was adjusted, and a paper phenol resin laminate having a density of 1.1 g / cm ³ was used as a carbon material.
Grinding step 1: The carbon raw material was charged into a grinder (DAS-20 manufactured by Daiko Seiki Co., Ltd.) to grind the carbon raw material. At that time, the carbon raw material was ground so that the ratio of 3.35 mm or less was 80% or more, assuming that the screen in the grinder was 8 mm in diameter.
Carbonization treatment step: 200 g of pulverized carbon raw material is put into a muffle furnace (manufactured by Koyo Thermo Co., Ltd.), and the temperature in the furnace is raised to 700 ° C. under nitrogen flow (2 L / min) (heating rate: 10 ° C./min) After holding, it was held for 2 hours to obtain a carbide of carbon material.
Activation treatment step: After 50 g of the above carbide is charged into a rotary kiln furnace (manufactured by TANAKA TEC Co., Ltd.) and heated up to a furnace temperature of 910 ° C. (10 ° C./min), steam is held under nitrogen (1 L / min) ) And was allowed to flow through the furnace (water vapor concentration 70 vol%), steam activation was performed for 20 minutes, and activated carbon was obtained.
Grinding step 2: The obtained activated carbon was ground in a mortar until the particle size of the obtained activated carbon became 180 μm or less.
Washing step: The pulverized activated carbon was washed with 5.0% hydrochloric acid (60 ° C.) and then washed with warm water (60 ° C.) to produce activated carbon 1.

Example 2
The activated carbon obtained in the same manner as in Example 1 except that the steam activation time was changed to 9 minutes was subjected to the following treatment to produce an activated carbon 2.
Heat treatment process: The activated carbon after washing is put into a muffle furnace (manufactured by Koyo Thermo Co., Ltd.), heated to 900 ° C. (heating rate: 10 ° C./min) under nitrogen flow (2 L / min), and then for 2 hours The activated carbon 2 was produced by holding.

Example 3
Activated carbon 3 was produced in the same manner as in Example 2 except that the steam activation time was changed to 15 minutes.

Example 4
The activated carbon 1 of Example 1 was subjected to the following treatment to produce an activated carbon 4.
Heat treatment process: The activated carbon after washing is put into a muffle furnace, heated to 900 ° C. (temperature rising rate: 10 ° C./min) under nitrogen flow (2 L / min), and then held for 2 hours to hold the activated carbon 4 Manufactured.

Example 5
Activated carbon 5 was produced in the same manner as in Example 2 except that the steam activation time was changed to 30 minutes.

Example 6
After charging 50 g of carbonized carbon raw material of Example 1 into a rotary kiln furnace and raising the temperature in the furnace to 910 ° C. (heating rate: 10 ° C./min) under nitrogen gas flow (1 L / min), the temperature Carbon dioxide gas (2.3 L / min) was circulated in the furnace together with nitrogen gas (1.0 L / min) (carbon dioxide gas concentration of 70 vol%), and carbon dioxide gas activation was performed for 32 minutes to obtain activated carbon.
Pulverization step 2: The activated carbon was pulverized in a mortar until the particle diameter of the obtained activated carbon became 180 μm or less, to obtain an activated carbon.
The crushed activated carbon was subjected to the washing step and the heat treatment step under the same conditions as in Example 2 to produce activated carbon 6.

Comparative Example 1
Carbon raw material: Activated carbon No. 1 used in the example of Patent Document 1 The same carbon source as 1 was used. Specifically, the press pressure at the time of molding and pressing a laminate of paper phenol resin (prepreg) was adjusted, and a paper phenol resin laminate having a density of 1.44 g / cm ³ was used as a carbon material. In the same manner as in Example 1, the pulverizing step 1, the carbonization treatment step, the activation treatment step, and the pulverizing step 2 were performed to obtain an activated carbon. The obtained activated carbon was subjected to the washing step and the heat treatment step in the same manner as in Example 2 to produce activated carbon 7. Comparative Examples 1 to 3 are activated carbon simulating the invention example of Patent Document 1.

Comparative example 2
Activated carbon 8 was produced in the same manner as in Comparative Example 1 except that the steam activation time was changed to 30 minutes.

Comparative example 3
Activated carbon 9 was produced in the same manner as in Comparative Example 1 except that the steam activation time was changed to 45 minutes.

Comparative example 4
Water vapor was changed to carbon dioxide gas (2.3 L / min), it was circulated in the furnace with nitrogen (1 L / min) (carbon dioxide concentration 70 vol%), and it was the same as comparative example 1 except carbon dioxide gas activation was performed for 60 minutes The activated carbon 10 was manufactured.

  The measurement conditions of various characteristics in this example are as follows. The measurement results are shown in Table 1.

[Density of paper phenolic resin laminate]
The density of the paper phenol resin laminate was calculated based on the following equation.
Density of paper phenol resin laminate (g / cm ³ ) = mass of paper phenol resin laminate (g) / volume of paper phenol resin laminate (long cm × horizontal cm × thickness cm)

[Macro pore volume of carbide]
A sample (carbide) having a particle diameter of 0.5 mm or more in a mercury injection pressure range of 0.152 to 414 MPa was measured using a mercury porosimeter (Auto Pore IV 9520 manufactured by Micrometrics). For the analysis of the macro pore volume, the macro pore volume was determined using the integrated value of the mercury intrusion amount at pore diameters of 0.05 μm to 107 μm.
Moreover, the macro pore volume to 1 to 10 micrometers of pore diameters was calculated | required using the integration value of the mercury intrusion amount in 1 to 10 micrometers of pore diameters of a sample.
The pore size distribution based on the measurement results is shown in FIG.

[Pore distribution of activated carbon]
Each of the obtained activated carbon was vacuum dried at 200 ° C. from 0.2 g of activated carbon and then analyzed by the BJH method from the adsorption isotherm by the N ₂ gas adsorption method using ASAP 2400 (manufactured by Shimadzu Corporation) I asked for. The results are shown in FIG.

[Specific surface area of activated carbon]
After vacuum heating of 0.2 g of the sample (activated carbon) at 250 ° C., an adsorption isotherm is determined using a nitrogen adsorption device (ASAP-2400 manufactured by Micromeritics), and the specific surface area (m ² / m is determined by the BET method. g) was calculated.

[Total pore volume of activated carbon]
From the nitrogen adsorption isotherm, the nitrogen adsorption amount at relative pressure (p / p0) = 0.93 was taken as the total pore volume (cm ³ / g).

[Average pore size of activated carbon]
The average pore diameter was calculated based on the following equation, assuming that the shape of the pores formed in the activated carbon is cylindrical.
Average pore size (nm) = (4 × total pore volume (cm ³ / g)) / specific surface area (m ² / g) × 1000

[Water flow test]
In order to reduce the pressure loss due to fine powder, 2.0 g of activated carbon prepared by adjusting the particle size of activated carbon in the range of 53 to 180 μm is packed in a column (diameter 15 mm), JIS S 3201 (2010: household water purifier test method) The water flow test was performed according to. Specifically, raw water adjusted to have a chloroform concentration of 0.06 mg / L was passed through the column at a space velocity (SV) of 500 h ⁻¹ . The concentration of chloroform before and after passage through the column was quantitatively measured by head space gas chromatography. Assuming that the breakthrough point is 20% of the trichloromethane concentration of the effluent water to the column inflow water, the amount of trichloromethane water flow when the breakthrough point is reached (= [total filtered water amount to breakthrough point (L) / mass of activated carbon (g) ] Was calculated and it was set as filtration performance. The head space used was TurboMatrixHS manufactured by Perkin Elmer, and the gas chromatogram mass spectrometer used was QP2010 manufactured by Shimadzu Corporation.

[Equilibrium test]
After 0.5 g of chloroform (CHCl ₃ ) was diluted with 50 mL of methanol, it was further diluted 10 times with methanol to prepare a test stock solution. 2 mL of the test stock solution was diluted with pure water to prepare a 2 mg / L chloroform solution. A predetermined amount of activated carbon with a particle size adjusted to 180 μm or less for each test in a 100 mL brown Erlenmeyer flask (a quantity of activated carbon in each test is 0.013 g: 0.026 g: 0.065 g: 0.130 g: 0) After adding .260 g), the solution was filled with chloroform solution, sealed with a Teflon grease-coated glass stopper, and fixed with a clip. In addition, the mass of the flask before and after water injection was measured to calculate the mass of the chloroform solution in the flask. Thereafter, the Erlenmeyer flask was placed in a constant temperature bath maintained at 20 ° C., and stirred using a magnetic stirrer for 14 hours. After stirring, the activated carbon and the solution in the Erlenmeyer flask were filtered off with a syringe filter, and the obtained filtrate was used for the equilibrium concentration (mg / L) of chloroform in the same head space gas chromatogram method as the water passing test above. An adsorption isotherm was prepared by determining the equilibrium adsorption amount (mg / g) per 1 g of activated carbon divided by the activated carbon mass, and the equilibrium adsorption amount at an equilibrium concentration of 0.06 mg / L was calculated and used as the adsorption amount to chloroform. The results are shown in the "Equilibrium adsorption amount (mg / g)" column of the table. In addition, the adsorption isotherm measured the equilibrium concentration and equilibrium adsorption amount in the said predetermined quantity of activated carbon, and after creating an adsorption isotherm based on the result, the equilibrium adsorption amount in the said equilibrium concentration was computed.

  As shown in FIGS. 1 and 2, the macro pore volume of the low density carbide derived from the low density paper phenol resin laminate (Examples 1 to 6) is 1 to 10 .mu.m. 4) It can be seen that it is significantly increased over the high density carbide derived from. Furthermore, as shown in Table 1, when the activated carbons of Examples 1 to 6 and Comparative Examples 1 to 4 are compared between each group, no clear difference can be found in physical structure such as specific surface area, pore volume and average pore diameter A remarkable effect is obtained in the water flow test results shown in FIG. 3 and the equilibrium test results shown in FIG. Therefore, also from this result, the physical structure of the activated carbon is different due to the density of the paper phenol resin laminate, which is a carbon material, and it is effective to improve the water adsorption performance and the equilibrium adsorption performance. I understand.

  Moreover, Example 1 and Example 4 are activated carbons which the presence or absence of the heat processing after activation processing differs. Both have almost the same specific surface area, pore volume and average pore size of activated carbon, and no difference can be found in the physical structure based on them. However, the activated carbon of Example 4 subjected to the heat treatment shows superior water passing adsorption performance and equilibrium adsorption performance, and that the reduction of the amount of acidic functional groups by the heat treatment contributes to the improvement of the adsorption performance. I understand.

  Example 4 and Comparative Example 1 and Example 5 and Comparative Example 2 have the same activation conditions, but the activated carbon derived from the low density paper phenol resin laminate (Examples 4 and 5) is a high density paper phenol resin laminate ( The specific surface area, the pore volume, and the average pore diameter tend to increase as compared with the activated carbon derived from Comparative Examples 1 and 2), and the water adsorption performance and the equilibrium adsorption performance are also significantly improved. From this result as well, it is understood that the activated carbon derived from the low density paper phenol resin laminate has a physical structure effective for the improvement of the adsorption performance even if activation treatment is performed under the same conditions.

Claims (7)

BET specific surface area is 650 m ² / g or more and 1250 m ² / g or less,
Total pore volume is 0.25 cm ³ / g or more,
An average pore diameter of 1.8 nm or more and 4.0 nm or less,
Activated carbon whose chloroform water flow rate is 71 L / g or more in the following water flow test method.
Water passing test method: Test water is passed through a column packed with 2.0 g of activated carbon having a particle diameter of 53 to 180 μm, chloroform concentration before and after passing through the column is measured, and total filtered water amount up to the breakthrough point (L) The chloroform water flow rate (L / g) per 1 g is determined to obtain a chloroform water flow rate.
Test water: Distilled water with a chloroform concentration of 0.06 mg / L Space velocity (SV): 500 h ^-1
Chloroform concentration measurement method: Head space gas chromatograph Breakthrough point: When the concentration of chloroform in the column effluent to the column inlet water exceeds 20% The activated carbon according to claim 1, wherein the chloroform equilibrium adsorption amount in the following equilibrium test method is 4.5 mg / g or more.
Equilibrium test method: Fill a chloroform solution in a 100 mL Erlenmeyer flask containing a predetermined amount of activated carbon and a stirrer in full water, seal the plug, and stir at 20 ° C for 14 hours, filter out the contents of the Erlenmeyer flask, and filter Determine the equilibrium concentration (mg / L) of chloroform and the chloroform equilibrium adsorption amount (mg / g) per 1 g of activated carbon by the above-mentioned method for measuring the concentration of chloroform and create an adsorption isotherm, and at an equilibrium concentration of 0.06 mg / L The equilibrium adsorption amount (mg / g).
Test solution: Chloroform solution with a concentration of 0.06 mg / L Mass of Erlenmeyer: Measure the mass of Erlenmeyer before and after filling with chloroform solution Particle size of activated carbon: Particle size of 180 μm or less Amount of activated carbon in each test: 0.013 g, 0.026 g , 0.065 g, 0.130 g, 0.260 g
Adsorption isotherm: The equilibrium concentration and the equilibrium adsorption amount are measured for each predetermined amount of the activated carbon, and the adsorption isotherm is created based on the results. The activated carbon according to claim 1 or 2, wherein the activated carbon is obtained by subjecting a paper phenol resin laminate having a density of 1.3 g / cm ³ or less to carbonization treatment and then performing gas activation treatment. A method for producing an activated carbon, which comprises subjecting a paper phenol resin laminate having a density of 1.3 g / cm ³ or less to carbonization treatment and then performing gas activation treatment.   The method for producing activated carbon according to claim 4, wherein after the gas activation treatment, at least one selected from the group consisting of cleaning treatment, drying treatment, pulverizing treatment, and heat treatment is performed. 6. The method for producing activated carbon according to claim 4, wherein a pore volume of a pore diameter of 1 to 10 μm of carbide of the paper phenol resin laminate obtained by the carbonization treatment is 0.15 cm ³ / g or more.   The activated carbon for water purifiers obtained by the manufacturing method in any one of Claims 4-6.