WO2020065930A1

WO2020065930A1 - Activated carbon and method for producing said activated carbon

Info

Publication number: WO2020065930A1
Application number: PCT/JP2018/036346
Authority: WO
Inventors: 天能　浩次郎; 孝規塚▲崎▼
Original assignee: 関西熱化学株式会社; 株式会社Ｍｃエバテック
Priority date: 2018-09-28
Filing date: 2018-09-28
Publication date: 2020-04-02
Also published as: KR102576958B1; CN111247097A; CN111247097B; KR20210058742A

Abstract

Provided is an activated carbon having excellent adsorption performance. The activated carbon according to the present invention has a BET specific surface area of 650-1250 m²/g, a total pore volume of 0.25 cm³/g or more, an average pore diameter of 1.8-4.0 nm, and a chloroform flow rate of 71 L/g or more, as measured by the water-flow test method.

Description

Activated carbon and method for producing the activated carbon

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 adsorbents, electrode materials for capacitors, and catalysts. Raw materials for activated carbon include plant materials such as sawdust, wood chips and coconut shells; polymer materials such as phenolic resin, polyacrylonitrile, polyimide, and composites thereof (such as paper phenolic resin); coal, petroleum, and coke Mineral materials such as various pitches are used.

The present inventors have paid attention to the fact that paper phenolic resin can control mesopores and micropores formed by controlling activation conditions, and have proposed activated carbon having a pore structure suitable for an object to be adsorbed ( Patent Document 1). More specifically, as an activated carbon exhibiting not only an equilibrium adsorption amount for an organic halogen compound, but also excellent adsorption performance even under water-passing conditions, a pore volume ratio of pore diameters of 2 nm or less and a pore volume ratio of more than 2 nm and 10 nm or less Activated carbon with controlled carbon content is disclosed.

WO 2015/152391 pamphlet

After the present inventors developed the activated carbon disclosed in Patent Literature 1, the present inventors continued research for the purpose of further improving the adsorption performance of activated carbon.

The present invention has been made in view of the above situation, and an object of the present invention is to provide an activated carbon having excellent adsorption performance and a method for producing the activated carbon.

[1] The activated carbon of the present invention that can solve the above-mentioned problem is:
BET specific surface area of 650 m ² / g or more, 1250 m ² / g or less,
Total pore volume of 0.25 cm ³ / g or more,
Average pore diameter of 1.8 nm or more and 4.0 nm or less,
The water flow rate of chloroform in the following water flow test method is 71 L / g or more.
Passage test method: Test water was passed through a column filled with 2.0 g of activated carbon having a particle diameter of 53 to 180 μm, the chloroform concentration before and after passing through the column was measured, and the total amount of filtered water (L) up to the breakthrough point was used to determine the activated carbon. The chloroform water flow rate (L / g) per 1 g is determined to be the 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: Headspace gas chromatograph Breakthrough point: When the concentration of chloroform in the column effluent with respect to the column inflow exceeds 20% in water

[2] The activated carbon of the present invention is also preferably the activated carbon according to [1], which has a chloroform equilibrium adsorption amount of 4.5 mg / g or more in the following equilibrium test method.
Equilibrium test method: A 100 mL Erlenmeyer flask containing a predetermined amount of activated carbon and a stirrer was filled with a chloroform solution and filled with water, sealed, stirred at 20 ° C. for 14 hours, and the contents of the Erlenmeyer flask were filtered off and filtered. The chloroform was used to determine the equilibrium concentration of chloroform (mg / L) and the equilibrium adsorption amount of chloroform per 1 g of activated carbon (mg / g), and an adsorption isotherm was prepared. The equilibrium adsorption amount (mg / g) is used.
Test solution: chloroform solution having a concentration of 0.06 mg / L Mass of Erlenmeyer flask: Measure mass of Erlenmeyer flask before and after filling with chloroform solution Activated carbon particle size: Particle size of 180 μm or less Activated carbon amount 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], wherein the activated carbon is obtained by carbonizing a paper phenolic resin laminate having a density of 1.3 g / cm ³ or less and then performing a gas activation treatment. .

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

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

[6] The above-mentioned [4] or [5], wherein the carbonized material of the paper phenolic resin laminate obtained by the carbonizing treatment has a pore volume of 1 to 10 μm in pore diameter of 0.15 cm ³ / g or more. Method for producing activated carbon.

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

According to the present invention, it is possible to provide an activated carbon having characteristics that are more excellent in adsorption performance than the activated carbon of the prior art, and a method for producing the activated carbon.

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 macropore 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 flow rate of chloroform in a flow test. FIG. 4 is a graph showing the relationship between the specific surface area of activated carbon and the equilibrium adsorption amount of chloroform 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 of the activated carbon of the example analyzed by the BJH method from the N ₂ adsorption isotherm.

(4) The present inventors have repeatedly studied to improve the adsorption performance over conventional activated carbon, and as a result, have found that the above-mentioned problems can be solved by improving a paper-phenol resin laminate used as a carbon raw material. Conventionally, as a carbon raw material of activated carbon, a scrap material of a paper phenol resin laminate generally used as a printed circuit board for electronic parts and the like has been used. The paper phenolic resin laminate for printed circuit boards has been densified to improve various properties such as durability, but surprisingly the paper phenolic resin laminate whose density was controlled lower than before was used as a carbon raw material. The present inventors have found that activated carbon can improve the adsorption performance, and have reached the present invention. Hereinafter, the present invention will be described.

The activated carbon of the present invention targets various substances to be adsorbed in the same manner as known activated carbons. It has excellent adsorption performance for organic halogen compounds such as trichloroethylene, more preferably trihalomethanes, and further preferably chloroform. In the present invention, the adsorption performance means that the substance to be adsorbed preferably has excellent adsorption performance under water-passing conditions (hereinafter, sometimes referred to as water-permeation adsorption performance), and more preferably equilibrium. It is also excellent in the amount of adsorption (hereinafter sometimes referred to as equilibrium adsorption performance). Hereinafter, the term “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, 1250 m ² / g or less, a 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 flow rate of chloroform in the described flow test method is 71 L / g or more.

Activated carbon of the present invention has superior permeable adsorption performance compared to conventional activated carbon. Although the excellent water permeation adsorption performance of the present invention is derived from a new carbon material different from the conventional one as described later, it is not possible to specify the physical structure derived from the carbon material even by examining the produced activated carbon. Have difficulty. However, since the water absorption capacity is superior to that of conventional activated carbon, there is a difference in the physical structure, and it is clear that the activated carbon is also new. Specified by the amount of water. Specifically, the activated carbon of the present invention has a water flow rate of 71 L / g or more, preferably 75 L / g or more, more preferably 78 L / g or more as a water flow rate capable of maintaining a chloroform removal rate of 80% or more based on the water flow test in Examples described later. , More preferably at least 80 L / g, even more preferably at least 85 L / g, most preferably at least 95 L / g.

Equilibrium adsorption performance The activated carbon of the present invention has excellent equilibrium adsorption performance as compared with conventional activated carbon. The excellent equilibrium adsorption performance of the present invention is also derived from a novel carbon raw material, as is the case with the water permeation adsorption performance, but is defined as 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 has a chloroform adsorption amount of preferably 4.5 mg / g or more, more preferably 5.0 mg / g or more, and still more preferably 5.0 mg / g of activated carbon based on the equilibrium test in Examples described later. It is at least 5 mg / g, more preferably at least 6.0 mg / g. The activated carbon of the present invention may satisfy only the water permeation adsorption performance, but preferably satisfy both the water permeation 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, and still more preferably 800 m ² / g in order to secure a sufficient amount of adsorption. It is more preferably at least 850 m ² / g, most preferably at least 900 m ² / g. On the other hand, the BET specific surface area is 1250 m ² / g or less, more preferably 1200 m ² 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 improvement of the diffusion rate and considering the packing density of the activated carbon. ² / g 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 having 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 0.80 cm ³ / g or less, more preferably 0.75 cm ³ / g or less, further preferably 0.70 cm ³ / g or less, and still 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 efficiency of introducing an adsorbate into the activated carbon. It is preferably at least 1.87 nm, most preferably at least 1.90 nm. On the other hand, if the average pore diameter is too large, the packing density may decrease, so that the average pore diameter is 4.0 nm or less, preferably 3.5 nm or less, and more preferably 3.0 nm or less.

Average Particle Size of Activated Carbon The activated carbon of the present invention can be formed into a shape and size according to the application. When activated carbon is used for water purifiers or the like, powder, granules, or granules thereof are preferable in consideration of contact efficiency. The average particle size of the activated carbon (that is, powdery, granular, or the average particle size of these granules) is preferably 10 μm or more, more preferably 20 μm or more, further preferably 30 μm or more in consideration of the above contact efficiency. , Preferably 500 μm or less, more preferably 300 μm or less, and still more preferably 200 μm or less.

優れ The excellent water permeation adsorption performance and equilibrium adsorption performance of the present invention are derived from the predetermined carbon raw material of the present invention. Therefore, when a different carbon material is used even when the BET specific surface area, the total pore volume, and the average pore diameter are within the above ranges, a physical structure different from the activated carbon derived from the predetermined carbon material of the present invention is obtained. Therefore, the water permeation adsorption performance and the equilibrium adsorption performance of the present invention cannot 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 raw material. Specifically, the activated carbon of the present invention is preferably obtained by subjecting a low-density paper phenolic resin laminate to a carbonization treatment and then performing a 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 a high-density paper phenolic resin laminate). Has adsorption performance. Therefore, the activated carbon derived from the low-density paper phenolic 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 specify the characteristics of the physical structure of the activated carbon of the invention from the electron microscope (SEM) photograph to the extent that it can be distinguished from the comparative example. It is difficult. As for the pore size distribution of the activated carbon, as shown in FIG. 6, it is difficult to distinguish the activated carbon of the invention from the activated carbon of the comparative example, and it is difficult to identify the characteristics of the activated carbon according to the invention even by examining with other various analyzers. It is. Therefore, one of the characteristics of the activated carbon of the present invention is that the activated carbon is preferably derived from a specific carbon material. In addition, the activated carbon derived from the conventional high-density paper phenol resin laminate does not provide the excellent adsorption performance of the present invention, and therefore can be distinguished from the conventional activated carbon by defining the degree of the effect obtained.

Paper phenol resin laminate In the present invention, a low-density paper phenol resin laminate is used as a carbon raw material. The paper phenolic resin laminate is a composite of a paper substrate on which relatively large pores are easily formed (hereinafter referred to as a raw material for forming mesopores) and a phenol resin on which relatively small pores are easily formed (hereinafter referred to as a raw material for forming micropores). Body. Then, when the carbide of the low-density paper phenolic resin laminate is subjected to a gas activation treatment, activated carbon having a pore structure that contributes to improving the water permeation adsorption performance and the equilibrium adsorption performance is obtained. The density of the paper phenol resin laminate specified in the present invention is lower than that of the known paper phenol resin laminate, and is a novel material. Activating the charcoal of such a novel paper phenolic resin laminate provides activated carbon having a physical structure different from that of the conventional high-density paper phenolic resin laminate.

In the present invention, the low-density paper phenolic resin laminate is carbonized, and the carbide derived from the low-density paper phenolic resin laminate has a pore size of 1 as shown in FIG. A pore volume of １０10 μm is significantly developed. And the carbide derived from the low-density paper phenolic resin laminate having such a unique pore structure is different from the carbide derived from the high-density paper phenolic resin laminate in the manner of gas diffusion in the carbide during the gas activation treatment. Considered different. That is, it is considered that the carbide derived from the low-density paper phenolic resin laminate has a low density, so that the gas activation treatment has a high gas diffusivity inside, and affects the formed pores and pore structure. Activated carbon derived from low-density paper phenolic resin laminate due to the difference in the formation process of such pores and pore structure is activated carbon derived from high-density paper phenolic resin laminate that has been carbonized and activated under the same conditions. Are considered to have different physical structures, and this 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 1.15 g / cm ³ or less. The lower limit of the density of the paper phenol resin laminate is preferably at least 0.70 g / cm ³ , more preferably at least 0.80 g / cm ³ , still more preferably at least 0.90 g / cm ³ , and most preferably 1.00 g / cm 3. ³ or more.

The raw material constituting the low-density paper phenolic resin laminate of the present invention can be the same paper as the paper phenolic resin laminate used in conventional printed circuit boards and the like, and phenolic resin, and other additives, and compositions Is not limited. Further, the method for producing the low-density paper phenolic resin laminate can be produced according to a conventional production method, but it is necessary to adjust the production conditions so as to obtain the above density. For example, the density of the paper phenolic resin laminate can be adjusted to a desired low density by adjusting the pressing pressure when forming and pressing a laminate of the paper phenolic resin (prepreg) obtained by impregnating the paper base material with the phenolic resin. . The paper phenolic resin laminate is formed under high press pressure in order to provide strength and durability suitable for a printed circuit board for electronic components and the like. For this reason, known paper phenolic resin molded articles are densified, and all of them exceed the predetermined density of the present invention. On the other hand, the low-density paper phenolic resin laminate of the present invention can be obtained by reducing the pressing pressure, but the strength and durability are low due to the low density, which is not suitable for printed circuit boards. It has the required strength and durability.

Crushing process 1
In the present invention, the low-density paper phenolic resin laminate may be pulverized before the carbonization. For example, by making the low-density paper phenolic resin laminate finer, uniform carbonization and activation treatment can be performed in a short time. Therefore, it may be appropriately pulverized according to the size of the carbonization furnace. For example, preferably 70% or more, more preferably 75% or more, even more preferably 80% or more of the low-density paper phenolic resin laminate after pulverization, preferably has a particle size of 5.0 mm or less, more preferably 4.0 mm or less, More preferably, it is desirable to be 3.35 mm or less. The lower limit may be appropriately determined in consideration of handleability and the like.

Carbonization Step The carbonization step is a step of carbonizing the low-density paper phenolic resin laminate to obtain a carbide. A carbide obtained by carbonizing a low-density paper phenolic 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). Remarkably develops. When a low-density carbide having a developed macropore volume is subjected to a gas activation treatment, gas diffusivity at the time of gas activation is improved, and the obtained activated carbon has a pore structure that contributes to an improvement in 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 macropore volume of 1 to 10 μm to the total macropore volume of the low-density carbide is preferably 40% or more, more preferably 45% or more, still more preferably 50% or more, and still more preferably 55% or more. . The higher the macropore volume ratio, the better the gas diffusibility at the time of the activation treatment is improved, and a pore structure that contributes to the improvement of the adsorption performance of the obtained activated carbon is obtained, which is preferable.

Carbonization conditions are preferably adjusted appropriately so as to obtain a low-density carbide having the above macropore volume. The atmosphere during the carbonization treatment is preferably an inert gas atmosphere such as nitrogen gas, helium, argon gas, or the like. Further, it is desirable that the heat treatment is performed at a temperature and for a time at which the low-density paper phenol resin laminate does not burn, and the temperature of the carbonization treatment (furnace temperature) is preferably 500 ° C. or more, more preferably 550 ° C. or more, and is preferably 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, even more preferably 10 minutes or more, preferably 10 hours or less, more preferably 8 hours or less, and even more preferably 6 hours or less. Less than an hour.

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

条件 The conditions of the gas activation treatment step may be appropriately adjusted so as to obtain the above activated carbon. The gas activation treatment is a method of heating the carbide to a predetermined temperature and then supplying the activation gas to perform the activation treatment. The temperature (furnace temperature) at the time of performing the gas activation treatment is preferably 400 ° C. or higher, more preferably 500 ° C. or higher, further preferably 600 ° C. or higher, preferably 1500 ° C. or lower, more preferably 1300 ° C. or lower, More preferably, it is 1100 ° C or lower. The heating rate at this time is preferably 1 ° C./min or more, more preferably 2 ° C./min or more, even more preferably 6 ° C./min or more, preferably 100 ° C./min or less, more preferably 50 ° C./min. Minutes or less, more preferably 25 ° C./minute or less. The heating holding time is preferably at least 0.1 hour, more preferably at least 0.25 hour, preferably at most 10 hours, more preferably at most 7.5 hours.

水蒸気 As the activation gas, steam, air, carbon dioxide, oxygen, combustion gas, and a mixed gas thereof can be used. Hereinafter, steam will be described as an example, but the present invention can be similarly applied to other activation gases such as carbon dioxide gas. When supplying steam, the concentration of steam supplied during the activation treatment is preferably at least 40 Vol%, more preferably at least 50 Vol%, still more preferably at least 60 Vol%, preferably at most 100 Vol%, more preferably at least 90 Vol%. Or less, more preferably 85% by volume or less. When the supplied water vapor concentration is within the above range, the pore formation by the activation reaction becomes better, and the activation reaction proceeds more efficiently, and the productivity can be improved.

As a mode of supplying steam, any of a mode of supplying steam without diluting and a mode of supplying steam diluted with an inert gas is possible, but in order to allow the activation reaction to proceed efficiently, A mode in which the solution is supplied after being diluted with a 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 further preferably 70 kPa or more.

Treatment after gas activation treatment The 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) crushing treatment 2, and (d) heating treatment. You may. (A) The washing treatment is performed on the 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 the activated carbon after activation of steam or after washing. The drying treatment may be performed by exposing the activated carbon to room temperature or under heating for a predetermined time to dry. (C) The pulverization process 2 is a step of adjusting the particle size of the activated carbon to a size according to the application. The pulverization process 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 as necessary. (D) The heat treatment is a step of heating the activated carbon at a high temperature under an inert atmosphere. By performing the heat treatment, the amount of acidic functional groups of the activated carbon can be reduced or removed. The activated carbon derived from the low-density paper phenolic resin laminate of the present invention can improve the adsorption performance by reducing the amount of the acidic functional group, and thus it is preferable to perform (d) heat treatment. The inert atmosphere during the heat treatment is the same as in the carbonization step. The heat treatment may be carried out at a temperature and for a time capable of reducing the number of acidic functional groups, and is preferably 400 ° C. or higher, more preferably 600 ° C. or higher, preferably 1300 ° C. or lower, more preferably 1200 ° C. or lower. The heating holding time is preferably 0.5 hours or more, more preferably 1 hour or more, further preferably 1.5 hours or more, preferably 10 hours or less, more preferably 8 hours or less.

処理 The treatment after the above-mentioned gas activation treatment may be performed alone or in an arbitrary combination of two or more treatments. When the cleaning treatment is combined with another treatment, the cleaning treatment may be performed before or after the pulverization treatment. However, it is desirable that the cleaning treatment be performed before the drying treatment or the heat treatment. Preferred combinations of the plurality of treatments are (i) grinding treatment-washing treatment, (ii) washing treatment-crushing treatment, and more preferred combinations are (iii) grinding treatment-washing treatment-drying treatment, and (iv) washing treatment-crushing. A treatment-drying treatment is more preferable, and a more preferred combination is (v) a crushing treatment-washing treatment-heating treatment, and (vi) a washing treatment-crushing treatment-heating treatment. Note that heat treatment may be performed after the drying treatment, but since the activated carbon can be dried by the heat treatment, the drying treatment may be omitted in consideration of treatment efficiency. In the above preferred combinations (iii) to (vi), the pulverization treatment may be omitted if no particle size adjustment or the like is required. In addition, a classification process using a sieve or the like may be performed as necessary in order to adjust the particle size, or a classification process may be performed as a final step after the above process.

The activated carbon of the present invention can be used as an adsorbent for an object to be adsorbed existing in the air or water. In particular, it is suitable for removing the following adsorbed substances contained in tap water and industrial wastewater, and is more preferably used as 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.

Hereinafter, the present invention will be described more specifically with reference to Examples. However, the present invention is not limited to the following Examples, and may be appropriately modified within a range that can conform to the purpose of the preceding and the following. It is, of course, possible to implement them, and all of them are included in the technical scope of the present invention.

Example 1
Carbon raw material: The paper phenolic resin laminate having a density of 1.1 g / cm ³ was used as the carbon raw material by adjusting the pressing pressure when forming and pressing the laminate of the paper phenolic resin (prepreg).
Pulverization Step 1: The carbon raw material was charged into a pulverizer (DAS-20 manufactured by Daiko Seiki Co., Ltd.) to pulverize the carbon raw material. At that time, the carbon material was pulverized so that the ratio of 3.35 mm or less was 80% or more with the screen in the pulverizer having a diameter of 8 mm.
Carbonization process: 200 g of the pulverized carbon material is put into a muffle furnace (manufactured by Koyo Thermo Co., Ltd.), and the temperature inside the furnace is raised to 700 ° C. under a nitrogen flow (2 L / min) (heating rate: 10 ° C./min). After that, the mixture was kept for 2 hours to obtain a carbide as a carbon raw material.
Activation treatment step: 50 g of the above-mentioned carbide was put into a rotary kiln furnace (manufactured by Tanaka Tech Co., Ltd.) and heated to a furnace temperature of 910 ° C. (10 ° C./min). ) Together with the mixture (steam concentration: 70% by volume), and activated by steam for 20 minutes to obtain activated carbon.
Pulverization step 2: The obtained activated carbon was pulverized in a mortar until the particle diameter 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
Activated carbon 2 was produced by performing the following treatment on the activated carbon obtained in the same manner as in Example 1 except that the steam activation time was changed to 9 minutes.
Heat treatment step: The activated carbon after washing is put into a muffle furnace (manufactured by Koyo Thermo Co., Ltd.), and heated to 900 ° C. under a nitrogen flow (2 L / min) (heating rate: 10 ° C./min), and then for 2 hours Activated carbon 2 was produced while maintaining the temperature.

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
Activated carbon 1 of Example 1 was subjected to the following treatment to produce activated carbon 4.
Heat treatment step: 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 maintained for 2 hours to remove 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
50 g of the carbonized carbon raw material of Example 1 was charged into a rotary kiln furnace, and the temperature in the furnace was raised to 910 ° C. (heating rate: 10 ° C./min) under a nitrogen gas flow (1 L / min). While maintaining the above, carbon dioxide gas (2.3 L / min) was passed through the furnace together with nitrogen gas (1.0 L / min) (carbon dioxide gas concentration: 70 Vol%), and carbon dioxide gas activation was performed for 32 minutes to obtain activated carbon.
Pulverizing step 2: The obtained activated carbon was pulverized in a mortar until the particle diameter became 180 μm or less, to obtain activated carbon.
A washing step and a heat treatment step were performed on the pulverized activated carbon under the same conditions as in Example 2 to produce activated carbon 6.

Comparative Example 1
Carbon raw material: Activated carbon No. used in Examples of Patent Document 1 The same carbon material as in Example 1 was used. Specifically, the press pressure at the time of forming and pressing the laminate of paper phenolic resin (prepreg) was adjusted, and a paper phenolic resin laminate having a density of 1.44 g / cm ³ was used as a carbon raw material. Activated carbon was obtained by performing the pulverizing step 1, the carbonizing step, the activation processing step, and the pulverizing step 2 in the same manner as in Example 1. The activated carbon thus obtained was subjected to a washing step and a heat treatment step in the same manner as in Example 2 to produce an activated carbon 7. Note that Comparative Examples 1 to 3 are activated carbons simulating the invention examples 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
The same as Comparative Example 1 except that the steam was changed to carbon dioxide (2.3 L / min) and passed through a furnace together with nitrogen (1 L / min) (carbon dioxide concentration: 70 Vol%), and carbon dioxide activation was performed for 60 minutes. Activated carbon 10 was produced.

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

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

[Macropore volume of carbide]
Using a mercury porosimeter (Auto Pore IV 9520 manufactured by Micrometrics), a sample (carbide) having a particle size of 0.5 mm or more in a mercury intrusion pressure range of 0.152 to 414 MPa was measured. In the analysis of the macropore volume, the macropore volume was determined using the integrated value of the mercury intrusion amount in the pore diameter of 0.05 μm to 107 μm.
The macropore volume of the sample having a pore diameter of 1 to 10 μm was determined using the integrated value of the mercury intrusion amount at the pore diameter of 1 to 10 μm of the sample.
FIG. 1 shows the pore size distribution based on the measurement results.

[Pore distribution of activated carbon]
Each activated carbon obtained was dried by vacuum drying 0.2 g of activated carbon at 200 ° C., and analyzed by AJ2400 (manufactured by Shimadzu Corporation) from the adsorption isotherm by the N ₂ gas adsorption method by the BJH method to determine the pore size distribution. I asked. FIG. 6 shows the results.

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

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

[Average pore size of activated carbon]
The average pore diameter was calculated based on the following formula, assuming that the shape of the pores formed in the activated carbon was cylindrical.
Average pore diameter (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 in which the particle diameter of activated carbon was adjusted within the range of 53 to 180 μm was packed in a column (15 mm in diameter), and JIS S 3201 (2010: Test method for household water purifier) ) Was conducted according to the test. 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 chloroform concentration before and after passing through the column was quantitatively measured by a head space gas chromatogram method. The breakthrough point is assumed to be 20% of the concentration of trichloromethane in the effluent with respect to the column inflow water, and the flow rate of trichloromethane at the time of reaching the breakthrough point (= [total amount of filtered water up to the breakthrough point (L) / mass of activated carbon (g)) ]) Was calculated and defined as filtration performance. The head space used was TurboMatrix HS manufactured by PerkinElmer, and the gas chromatogram mass spectrometer used was QP2010 manufactured by Shimadzu Corporation.

[Equilibrium test]
After diluting 0.5 g of chloroform (CHCl ₃ ) with 50 mL of methanol, it was further diluted 10 times with methanol to obtain a test stock solution. 2 mL of the test stock solution was diluted with pure water to prepare a chloroform solution having a concentration of 2 mg / L. A stirrer and a predetermined amount of activated carbon having a particle size adjusted to 180 μm or less for each test were placed in a brown Erlenmeyer flask having a capacity of 100 mL (the amount of activated carbon in each test was 0.013 g: 0.026 g: 0.065 g: 0.130 g: 0). .260 g), filled with chloroform solution, filled with a glass stopper coated with Teflon (registered trademark) grease, and fixed with a clip. The mass of the flask solution 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 thermostat maintained at 20 ° C., and stirred for 14 hours using a magnetic stirrer. After stirring, the activated carbon and the solution in the Erlenmeyer flask were filtered off with a syringe filter, and the obtained filtrate was subjected to the same headspace gas chromatogram method as in the above water-passing test, and the equilibrium concentration of chloroform (mg / L) and used. An adsorption isotherm was created by obtaining the equilibrium adsorption amount (mg / g) per 1 g of activated carbon divided by the mass of the activated carbon, and the equilibrium adsorption amount at an equilibrium concentration of 0.06 mg / L was calculated to be the adsorption amount to chloroform. The results are shown in the "Equilibrium adsorption amount (mg / g)" column in the table. The adsorption isotherm was obtained by measuring the equilibrium concentration and the equilibrium adsorption amount of the activated carbon at the above-mentioned predetermined amount, creating an adsorption isotherm based on the results, and then calculating the equilibrium adsorption amount at the above-mentioned equilibrium concentration.

As shown in FIGS. 1 and 2, the low-density carbide derived from the low-density paper phenol resin laminate (Examples 1 to 6) has a macropore volume of 1 to 10 μm which is high-density paper phenol resin laminate (Comparative Examples 1 to 6). 4) It is found that the density is remarkably increased as compared with that of the high-density carbide derived from 4). Further, as shown in Table 1, when the activated carbons of Examples 1 to 6 and Comparative Examples 1 to 4 are compared with each other in each group, no clear difference can be found in the physical structure such as specific surface area, pore volume and average pore diameter. A remarkable effect is obtained in the results of the water flow test shown in FIG. 3 and the results of the equilibrium test shown in FIG. Therefore, the results also show that the physical structure of the activated carbon differs due to the density of the paper phenolic resin laminate, which is the carbon raw material, and that this has effectively acted to improve the water adsorption performance and the equilibrium adsorption performance. I understand.

Examples 1 and 4 are activated carbons having different heat treatments after the activation treatment. Both have substantially the same specific surface area, pore volume, and average pore diameter of activated carbon, and no difference can be found in the physical structure based on these. However, the activated carbon of Example 4 which had been subjected to the heat treatment exhibited better water permeation adsorption performance and equilibrium adsorption performance, and that reducing the amount of acidic functional groups by heat treatment contributed to the improvement of the adsorption performance. I understand.

Example 4 and Comparative Example 1 and Example 5 and Comparative Example 2 are under the same activation conditions, but activated carbon (Examples 4 and 5) derived from a low-density paper phenolic resin laminate (Examples 4 and 5) is used. The specific surface area, the pore volume, and the average pore diameter tend to be higher than those of the activated carbons derived from Comparative Examples 1 and 2), and the water permeation adsorption performance and the equilibrium adsorption performance are remarkably improved. This result also indicates that the activated carbon derived from the low-density paper phenolic resin laminate has a physical structure effective for improving the adsorption performance even when the activation treatment is performed under the same conditions.

Claims

BET specific surface area of 650 m 2 / g or more, 1250 m 2 / g or less,
Total pore volume of 0.25 cm 3 / g or more,
Average pore diameter of 1.8 nm or more and 4.0 nm or less,
Activated carbon having a chloroform flow rate of 71 L / g or more in the water flow test method described below.
Passage test method: Test water was passed through a column filled with 2.0 g of activated carbon having a particle diameter of 53 to 180 μm, the chloroform concentration before and after passing through the column was measured, and the total amount of filtered water (L) up to the breakthrough point was used to determine the activated carbon. The chloroform water flow rate (L / g) per 1 g is determined to be the 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: Headspace gas chromatograph Breakthrough point: When the concentration of chloroform in the column effluent with respect to the column inflow exceeds 20% in water
The activated carbon according to claim 1, wherein the equilibrium adsorption amount of chloroform in the following equilibrium test method is 4.5 mg / g or more.
Equilibrium test method: A 100 mL Erlenmeyer flask containing a predetermined amount of activated carbon and a stirrer was filled with a chloroform solution and filled with water, sealed, stirred at 20 ° C. for 14 hours, and the contents of the Erlenmeyer flask were filtered off and filtered. The chloroform was used to determine the equilibrium concentration of chloroform (mg / L) and the equilibrium adsorption amount of chloroform per 1 g of activated carbon (mg / g), and an adsorption isotherm was prepared. The equilibrium adsorption amount (mg / g) is used.
Test solution: chloroform solution having a concentration of 0.06 mg / L Mass of Erlenmeyer flask: Measure mass of Erlenmeyer flask before and after filling with chloroform solution Activated carbon particle size: Particle size of 180 μm or less Activated carbon amount 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 claim 1, 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 a carbonization treatment and then performing a gas activation treatment.
A method for producing activated carbon, comprising subjecting a paper phenolic resin laminate having a density of 1.3 g / cm 3 or less to a carbonizing treatment and then performing a 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 a washing treatment, a drying treatment, a crushing treatment, and a heat treatment is performed.
6. The method for producing activated carbon according to claim 4, wherein a pore volume of pores having a pore diameter of 1 to 10 μm of the carbide of the paper phenolic resin laminate obtained by the carbonization treatment is 0.15 cm 3 / g or more.
活性 Activated carbon for a water purifier obtained by the production method according to any one of claims 4 to 6.