JP2006247527A - Adsorbent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adsorbent having an excellent adsorption property even in the case of dynamic adsorption such as water passing through treatment. <P>SOLUTION: The adsorbent of the present invention comprises porous carbon in which the ratio of the volume of pores having a pore size of 20 Å to 100 Å to the volume of pores having a pore size of 100 Å or smaller is 5 to 50% and the ratio of the volume of pores having a pore size of 10 Å or smaller to the volume of pores having a pore size of 100 Å or smaller is 45% or more. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an adsorbent, and more particularly to an adsorbent for water purification.

  Chlorine is added to tap water for drinking water for sterilization. Residual chlorine has an oxidative decomposition action of organic substances in addition to the sterilization action, and is a carcinogen such as trihalomethanes or other organic substances. Generates chlorinated compounds. Trihalomethanes have a small molecular weight, a relatively low boiling point, and a very low concentration in tap water. For this reason, since it is difficult for conventional activated carbon to sufficiently remove these harmful substances, activated carbon having a high specific surface area has generally been used to increase the adsorption capacity. As the activation method, the gas activation is overwhelmingly the most, but in recent years chemical activation activated with alkali hydroxide has also been performed, and in order to obtain the adsorption characteristics of specific components, the pore diameter Control of distribution and surface properties have been studied.

  For example, Patent Document 1 discloses activated carbon in which the ratio of pores having diameters of 6 to 8 mm to pore volumes of 100 mm or less is 65 vol% or more, and the amount of equilibrium adsorption that is a static adsorption force is increased. It is shown. Patent Document 2 discloses activated carbon having a surface acidic functional group of 0.1 meq / g or less. If the amount of acidic functional groups on the surface is large and the hydrophilicity is too high, the adsorption of water molecules is given priority in the adsorption in an aqueous solution, and the adsorption ability of the organic chlorine compound is reduced.

By the way, in recent years, new carbon materials such as fullerenes, soots containing fullerenes and residues obtained by extracting fullerenes have attracted attention. (For example, Non-Patent Document 1)
JP-A-9-110409 JP-A-8-289999 Minato Egashira et al, “Carbon framework structure produced in the Fullerene related material (carbon skeleton structure produced in fullerene related materials)” “Carbon” 38 (2000) 615-62

  In the original water flow treatment, since it is dynamic adsorption, the adsorption capacity is considerably lower than the equilibrium adsorption amount. That is, the adsorption rate is an important factor in the water treatment. For example, when a small pore having a diameter of 6 to 8 mm is formed as in Patent Document 1, although the equilibrium adsorption amount is increased, the diffusion rate in the pore becomes very slow. There is a problem that it cannot be adsorbed. Moreover, if the surface acidic functional group is reduced as in Patent Document 2, the diffusion rate of water molecules in the pores becomes extremely slow in the conventional adsorbent in the pore range, so In the treatment, there is a problem that the adsorption rate of trihalomethanes in water becomes extremely slow.

  This invention is made | formed in view of the said situation, and it aims at providing the adsorption agent which is excellent in adsorption | suction performance also in a dynamic adsorption aspect like a water flow process.

  The adsorbent of the present invention capable of solving the above problems has a pore volume ratio of 5 to 50% of a pore diameter of 20 to 100% with respect to a pore volume of 100 or less. It contains porous carbon having the following pore volume ratio of 45% or more.

In the present invention, with respect to the pore volume having a pore diameter of 100 mm or less, setting the pore volume ratio of the pore diameter of 20-100 mm to 5-50% increases the proportion of relatively large pores, This is to increase the adsorption power. On the other hand, since it is necessary to increase the equilibrium adsorption amount, which is a static adsorption force, the pore volume ratio with a pore diameter of 10 mm or less effective for the static equilibrium adsorption amount is set to 45% or more. By setting it as the above structures, static adsorption force and dynamic adsorption force can be made compatible. The upper limit of the pore volume ratio of the pore diameter of 10 mm or less is preferably 85%. Furthermore, it is also a preferable aspect that the pore volume ratio of the pore diameter of 20 to 100% is 5 to 30%. This is because the balance between the static adsorption force and the dynamic adsorption force is improved by making the pore volume of 10 mm or less and the pore volume of 20 mm to 100 mm constant. The BET specific surface area of the porous carbon is preferably 350 to 1450 m ² / g.

  The porous carbon used in the present invention is a new porous carbon obtained by activating a specific carbonaceous material. Fullerene, fullerene-containing soot, and at least a part of fullerene from the fullerene-containing soot are substantially contained. It is preferably obtained by activating at least one carbonaceous material selected from the group consisting of extraction residues obtained by extraction.

  The adsorbent of the present invention is excellent in both dynamic adsorption force and static adsorption force. In particular, it is suitable as an adsorbent for water purification in water flow treatment, and is excellent in adsorbing trihalomethanes or other organochlorine compounds.

  The adsorbent of the present invention has a pore volume ratio of 5% to 50% of a pore diameter of 20% (2 nm) to 100% (10 nm) with respect to a pore volume having a pore size of 100% (10 nm) or less, and a pore size of 10%. It contains porous carbon having a pore volume ratio of (1 nm) or less of 45% or more. The pores having a pore diameter of 20 to 100 mm are considered to be effective for increasing the dynamic adsorption force by increasing the diffusion rate of the adsorbed substance into the porous carbon. A pore volume ratio of 20 to 100% with respect to a pore volume having a pore size of 100 or less is set to 5% or more. If the pore volume ratio of the pore diameters of 20 to 100 is too low, the diffusion rate of the adsorbed substance into the porous carbon is lowered, and the dynamic adsorption force is reduced. On the other hand, if the pore volume ratio of pore sizes 20 to 100 is too high, on the other hand, relatively small pores effective for increasing the static adsorption force (equilibrium adsorption amount) (for example, pore sizes of 10 mm or less). The pore volume ratio may decrease and the amount of adsorption may decrease. Therefore, in the present invention, the pore volume ratio of 20 to 100% with respect to the pore volume having a pore size of 100 or less is 50% or less, more preferably 40% or less, and further preferably 30% or less.

  In addition, pores having a pore diameter of 10 mm or less in porous carbon are pores that are considered to be effective in increasing the static adsorption force (equilibrium adsorption amount). In the present invention, the pore diameter is 100 mm or less. The ratio of the pore volume of 10 mm or less to the pore volume is 45% or more, more preferably 50% or more. This is because if the volume ratio of the pores having a pore diameter of 10 mm or less is less than 45%, the static adsorption force (equilibrium adsorption amount) is too low. On the other hand, the ratio of the pore volume of 10 Å or less to the pore volume of 100 細孔 or less is 85% or less, more preferably 80% or less. On the other hand, if the pore volume ratio of 10 mm or less is too high, the pore volume ratio of pore diameters of 20 mm to 100 mm, which has an effect on the dynamic adsorption force, becomes too small, and the amount of adsorption as the entire porous carbon is reduced. It is because it falls.

  The ratio of the pore volume having a pore diameter of 100 mm or less to the total pore volume of the porous carbon used in the present invention is preferably 55% or more, more preferably 60% or more. The pores having a pore diameter of 100 mm or less have a function of increasing the static or dynamic adsorption force, and the porous carbon has a certain ratio so that the adsorption amount as a whole of the porous carbon can be increased. Because it becomes high.

Further, the ratio of the pore volume with a pore diameter of 100 mm or less to the total pore volume of the porous carbon used in the present invention tends not to be so high as compared with the conventional activated carbon, and the upper limit is not particularly limited. However, it is about 96%, more preferably about 90%.
The pore volume of the porous carbon can be measured using a nitrogen adsorption device of ASAP-2400 manufactured by Micromeritics, and the pore volume within a certain pore range can be obtained from the nitrogen relative pressure and the adsorption amount. it can.

  In general, the pores of porous carbon are roughly classified into micropores having a pore diameter of less than 20 mm, mesopores having a pore diameter of 20 to less than 500 mm, and macropores having a pore diameter of 500 mm or more. The porous carbon of the present invention is considered to have a structure in which the micropores and the macropores communicate efficiently in the mesopore region, and effective use of the entire pores from the micropores to the macropores. The rate is estimated to be much higher. As a result, it is considered that the adsorption performance is excellent.

That is, the porous carbon of the present invention preferably has a pore distribution measured by a nitrogen adsorption method, and the vertical axis indicates dV / dlog (D) (dV / dlog (D) is the frequency of pores (or finer). In the pore distribution diagram in which the horizontal axis is the pore diameter D (Å), the pore diameter D is 10 mm, 30 mm, 40 mm, and When the values of dV / dlog (D) at 100 と し た are V ₁₀ , V ₃₀ , V ₄₀ , and V ₁₀₀ respectively, V ₁₀₀ / V ₁₀ , V ₁₀₀ / V ₃₀ , and V ₁₀₀ / V ₄₀ satisfies the following conditions. Here, V ₁₀₀ / V ₁₀ , V ₁₀₀ / V ₃₀ , and V ₁₀₀ / V ₄₀ are pores having a pore diameter of 100 mm with respect to the amount of pores of 10 mm, 30 mm, and 40 mm in the porous carbon, respectively. It shows the ratio of the quantity. The V ₁₀₀ / V ₃₀ is 0.5 or more, more preferably 0.7 or more. V ₁₀₀ / V ₄₀ is preferably 0.6 or more, 0.8 or more, and more preferably 0.9 or more. By setting V ₁₀₀ / V ₃₀ and V ₁₀₀ / V ₄₀ to a certain value or more, the micropores and macropores communicate efficiently in the mesopore region. It is considered that the diffusion rate of the object into the porous carbon increases, and as a result, the amount of adsorption of the entire porous carbon increases. On the other hand, if V ₁₀₀ / V ₃₀ and V ₁₀₀ / V ₄₀ become too small, the pores in the mesopore region (particularly the pore size is 100 Å) that can be a passage to micropores having a pore size of less than 20 Å. Since the ratio of the amount is small, there is a possibility that the micropores cannot be effectively used. Also, V ₁₀₀ / V ₃₀ and, the upper limit of V ₁₀₀ / V ₄₀ is not particularly limited, preferably 2.0, more preferably about 1.5.

In addition, as described above, it is also a preferable aspect to make the amount of pores having a pore diameter of about 10 mm affecting static adsorption force within a certain range, and in the present invention, V ₁₀₀ / V _{10 is set} to 0.08 or more. Preferably it is 0.13 or more and 0.35 or less, more preferably 0.3 or less. It is also a preferable aspect that V _{100 is set} to 0.05 or more, more preferably 0.06 or more, and the absolute amount of pores near 100 mm is set to a certain value or more.

  The pore distribution of the porous carbon can be measured using an ASAP-2400 nitrogen adsorption device manufactured by Micromeritics, and analyzed by the BARRETT-JOYNER-HALENDA method (BJH method) in Shimadzu Corporation analysis software.

  The amount of the surface acidic functional group of the porous carbon used in the present invention is not particularly limited, but is 0.5 meq / g or less, more preferably 0.3 meq / g or less, and still more preferably 0.2 meq / g. The following is preferable.

  As described above, when the surface acidic functional group amount is high in adsorption in an aqueous solution, water molecules are preferentially adsorbed, so that the adsorption amount of adsorbed substances such as trihalomethanes or other organochlorine compounds decreases. Because there is. The surface acidic functional group amount of porous carbon is obtained by adsorbing a predetermined amount of strong alkali NaOEt (Natrimethethoxide), separating the supernatant, titrating with hydrochloric acid, and calculating the amount of alkali adsorption. Can be sought. Examples of the surface acidic functional group include a carboxyl group, an ester group, a hydroxyl group, and a keto group.

BET specific surface area of the porous carbon used in the present invention, but are not particularly limited, 350 meters ² / g or more, more preferably be at 400 meters ² / g or more, 1450 m ² / g or less, more preferably It is desirable that it is 1300 m ² / g or less, more preferably 900 m ² / g or less. The BET specific surface area of 350m less than ² / g, sometimes pores development is insufficient, the 1450 m ² / g greater, there is a case where density is too lowered.

  The pore volume of the porous carbon used in the present invention is not particularly limited, but is desirably 0.3 cc / g or more, more preferably 0.4 cc / g or more. This is because if the pore volume is too small, the amount of adsorption decreases. The upper limit of the pore volume is not particularly limited, but is desirably 1.0 cc / g, more preferably 0.7 cc / g.

  Next, the manufacturing method of the porous carbon used by this invention is demonstrated.

  The porous carbon used in the present invention is selected from the group consisting of fullerene, fullerene-containing soot, and an extraction residue obtained by substantially extracting at least a part of fullerene from the fullerene-containing soot using a solvent. It can be obtained by activating at least one carbonaceous material.

As is well known, fullerene is a carbon molecule having a hollow shell-like structure closed by a network of five-membered rings and six-membered rings. For example, C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₀ , C ₈₂ , C ₈₄ , C ₈₆ , C ₈₈ , C ₉₀ , C ₉₂ , C ₉₄ , C ₉₆ , C ₁₈₀ , C ₂₄₀ , C ₃₂₀ , C ₅₄₀ , or mixtures thereof may be mentioned. The fullerene-containing soot is not particularly limited as long as it is a soot that can be produced when producing fullerene. As a method for producing fullerene, for example, a method of evaporating a raw material by arc discharge using a graphite electrode (arc discharge method), a method of evaporating a raw material by passing a high current through a carbonaceous material (resistance heating method), an ultraviolet There are a method of irradiating a graphite with a laser (laser evaporation method), a method of incompletely burning a carbon-containing compound such as benzene (combustion method), etc., and any method can obtain soot containing fullerene. The fullerene-containing soot includes, in addition to the fullerenes described above, for example, fullerene precursors that did not reach a closed ring structure such as fullerene, graphite or carbon having a graphite structure, amorphous carbon, amorphous carbon, carbon black And polycyclic aromatic hydrocarbons (Non-Patent Document 1).

Examples of the fullerene-containing soot, be mentioned fullerene-containing soot containing fullerene-containing soot and the toluene soluble fullerenes containing C ₆₀ obtained by an arc discharge method or laser evaporation method at least 10% less than 5% by mass it can.

In the present invention, an extraction residue obtained by substantially extracting at least a part of fullerene from the fullerene-containing soot using a solvent can be used. An extraction residue obtained by substantially extracting at least a part of fullerene from a fullerene-containing soot using a solvent is a residue obtained by substantially extracting a fullerene component soluble in a solvent from the fullerene components contained in the fullerene-containing soot. Means a thing. For example, fullerene having a carbon number of C _{60 to} C ₇₀ is soluble in a solvent described later, and is extracted from the fullerene-containing soot with a solvent. An extraction residue obtained by substantially extracting at least a part of the fullerene from the fullerene-containing soot using a solvent includes a precursor of the fullerene, carbon having a graphite or a graphite structure, and amorphous carbon. , amorphous carbon, is believed to contain a carbon black or a C ₇₀ or higher order fullerenes.

According to Non-Patent Document 1, the toluene soluble content in the fullerene-containing soot produced by an arc discharge method using a graphite electrode is 10%, C ₆₀ : 70%, C ₇₀ : 22%, and a small amount of C _76. consists higher fullerenes of -C _120, the toluene-insoluble matter is clusters of C _60, C ₇₀ and analogous structures C ₄₀₀ from C _70. Further, when acetone is added to the toluene insoluble matter, the graphite-like substance is separated, but the amount is 15% of the fullerene-containing soot.

Examples of the solvent used when substantially extracting at least a part of fullerene from the fullerene-containing soot using a solvent include organic solvents such as aromatic hydrocarbons, aliphatic hydrocarbons, and chlorinated hydrocarbons. Examples thereof include aromatic organic solvents such as benzene, toluene, xylene, 1-methylnaphthalene, 1,2,4-trimethylbenzene, and tetralin, and among these, toluene is preferable. Using toluene, can be extracted C ₆₀ -C ₁₂₀ about fullerene.

  Examples of a method for obtaining an extraction residue by substantially extracting at least a part of fullerene from a fullerene-containing soot using a solvent include the following methods. First, a solvent having a mass of about 60 times is added to fullerene-containing soot to prepare a dispersion of fullerene-containing soot, and this dispersion is treated with ultrasonic waves at room temperature for 1 hour to be soluble in the solvent of fullerene-containing soot. The fullerene component and other solvent-soluble components are dissolved in the solvent. Next, the dispersion of the fullerene-containing soot is filtered, and the fullerene-containing soot is washed with a solvent until the filtrate is no longer colored, so that at least a part of the solvent-soluble fullerene and other solvent-soluble components are substantially removed. And the obtained extraction residue is vacuum-dried at about 60 ° C.

  Next, a method for activating the carbonaceous material in the present invention will be described.

  The “activation treatment” in the present invention is a treatment for making the above-described carbonaceous material porous, and it is a treatment that increases at least one of the specific surface area of the carbonaceous material or the pore volume. There is no particular limitation, and for example, chemical activation treatment, gas activation treatment, and the like can be employed. The chemical activation treatment is, for example, a method of activating the above-described carbonaceous material with an alkali metal compound, and can be performed by mixing and heat-treating the carbonaceous material and the alkali metal compound. Examples of the alkali metal compound include alkali metal hydroxides such as potassium hydroxide and sodium hydroxide; alkali metal carbonates such as potassium carbonate and sodium carbonate; alkali metal sulfates such as potassium sulfate and sodium sulfate; And aqueous solutions and hydrates thereof. Preferred as the activator is a hydrate or concentrated aqueous solution of an alkali metal hydroxide such as potassium hydroxide or sodium hydroxide. The amount of the alkali metal compound used with respect to the carbonaceous material is not particularly limited. For example, when potassium hydroxide is used as the alkali metal compound, potassium hydroxide / carbonaceous material (mass ratio) = 0. It is preferable that it is 3 or more and 4.0 or less. In the present invention, the mass ratio of the alkali metal compound / carbonaceous material can be further reduced. For example, when potassium hydroxide is used as the alkali metal compound, the mass ratio of potassium hydroxide / carbonaceous material is determined based on anhydrous standards. Therefore, it can be 2.5 or less, more preferably 1.5 or less. According to the present invention, the amount of alkali metal compound used can be reduced, which is economical.

  The heat treatment for the chemical activation is not particularly limited. For example, the heat treatment can be performed at 500 ° C. or more and 900 ° C. or less, and the heat treatment is also preferably performed in an inert gas atmosphere such as argon or nitrogen. It is an aspect.

  In this invention, you may perform a gas activation process, and it is a preferable aspect that a gas activation process is performed by contacting the carbonaceous substance mentioned above with oxidizing gas at 750 degreeC or more, for example. The temperature of the gas activation treatment is 800 ° C. or higher, more preferably 850 ° C. or higher, 1100 ° C. or lower, more preferably 1050 ° C. or lower. Moreover, as said oxidizing gas, a carbon dioxide gas, water vapor | steam, oxygen, combustion exhaust gas, a mixture thereof, etc. can be used, for example.

In the present invention, the carbonaceous material described above can also be activated simply by heat treatment. The porous carbon having a BET specific surface area of 350 m ² / g or more, more preferably 400 m ² / g or more and having a practical amount of adsorption can be obtained by simply heat-treating the above-mentioned carbonaceous material. Can do. The heat treatment temperature in this embodiment is not particularly limited, but is 750 ° C. or higher, more preferably 800 ° C. or higher, 1400 ° C. or lower, more preferably 1300 ° C. or lower, more preferably 1050 ° C. or lower. It is desirable. This is because if the heat treatment temperature is too low, the degree of pore development is too low, and if the heat treatment temperature is too high, the amount of porous carbon obtained may be reduced. The heat treatment of the carbonaceous material is preferably performed in an inert atmosphere. For example, the carbonaceous material is substantially inert in a crucible made of carbon that is easily oxidized in an inert gas atmosphere such as nitrogen or argon. It is preferable to carry out in an atmosphere. Moreover, the said heat processing can also be performed under pressure reduction, for example.

  In the heat treatment in this aspect, if the above-described oxidizing gas is used in combination, the above heat treatment and the above-described oxidizing gas activation treatment are performed in a superimposed manner. Moreover, it can also activate by combining suitably the activation process by heat processing, and the gas activation process using oxidizing gas, for example, continuing the gas activation process using oxidizing gas following the activation process by heat processing. Performing is also a preferred embodiment.

  In the present invention, it is also preferable to use porous carbon obtained by activating the carbonaceous material and then washing it with at least one selected from the group consisting of an acid, water, and an organic solvent. is there. In particular, when chemical activation is performed with an alkali metal hydroxide or the like, an unreacted activator present in the porous carbon or an alkali metal compound (for example, potassium) generated by the reaction by washing with acid and / or water. Compound) and the like are preferably removed. It is also a preferred embodiment to remove the acid and / or water contained in the porous carbon by drying the porous carbon obtained by washing.

  The porous carbon after the activation treatment may contain an organic solvent-soluble component. When porous carbon is used as an adsorbent for water purification, it is also a preferred aspect to remove this organic solvent soluble component beforehand. As the organic solvent for removing the organic solvent-soluble component from the porous carbon, it is preferable to use toluene, benzene or the like. It is also a preferred embodiment to remove the organic solvent contained in the porous carbon by vacuum drying the porous carbon extracted or washed with the organic solvent.

  In the present invention, it is also a preferable aspect to use porous carbon obtained by heat treatment in an inert gas atmosphere after the washing or activation treatment. This is because the amount of acidic functional groups on the surface of the porous carbon can be adjusted. As the heat treatment after the cleaning or the activation treatment, an embodiment in which the porous carbon immediately after the activation is heat-treated in an inert gas atmosphere; after the porous carbon immediately after the activation is washed with an acid and / or water, the inert gas is used. An embodiment in which heat treatment is performed in an atmosphere; an embodiment in which porous carbon immediately after activation is washed with an organic solvent and then heat treatment is performed in an inert gas atmosphere; a porous carbon immediately after activation is washed in an acid and / or water to be inert. Examples include an embodiment in which after the heat treatment is performed in a gas atmosphere, the substrate is further washed with an organic solvent and the heat treatment is performed in an inert gas atmosphere. As said inert gas, argon, nitrogen, helium etc. can be used, for example. The heat treatment temperature is not particularly limited, but is preferably 400 ° C. or higher and 1000 ° C. or lower.

  The pore volume ratio, pore volume, BET specific surface area, and the like of the porous carbon used in the present invention may be set to a desired range by appropriately changing the activation conditions. The adsorbent of the present invention may further contain conventional activated carbon or the like as long as the desired performance is not deteriorated in addition to the porous carbon described above.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments within the scope not departing from the gist of the present invention are described in the present invention. Included within the scope of the invention.

[Measurement method of pore volume of porous carbon]
The adsorption isotherm is determined by a nitrogen adsorption device of ASAP-2400 manufactured by Micromeritics. The total pore volume indicates the amount of adsorbed gas at a pressure close to the saturated vapor pressure as a value converted to a liquid. A pore volume of 10 liters or less than the adsorption amount at a relative pressure of 0.016, a pore volume of 20 liters or less from the adsorption amount at a relative pressure of 0.168, and a pore volume of 30 liters from the adsorption amount at a relative pressure of 0.350. The following pore volume was determined from the amount of adsorption at a relative pressure of 0.484 to a pore volume of 40 mm or less, and from the amount of adsorption at a relative pressure of 0.787, a pore volume of 100 mm or less was determined.

[Method for measuring BET specific surface area]
The BET specific surface area of the carbonaceous material and porous carbon was measured using an ASAP-2400 nitrogen adsorption device manufactured by Micromeritics.

[Adsorption test (water flow test)]
The water flow test was conducted by selecting chloroform, which is the most difficult to remove among the trihalomethanes. The obtained adsorbent was packed into a column with a diameter of 15 mmφ at a bed height of 10 mm, and test water adjusted to a chloroform concentration of 50 ppb was passed through this column at a space velocity of 1000 h ⁻¹ , and the discharged water was subjected to gas chromatography mass spectrometry. Analyzed by instrument. The point at which the chloroform concentration of the discharged water relative to the test water was 20% or more was regarded as the breakthrough point and the amount allowed to pass.

[X-ray diffraction measurement]
X-ray diffraction measurement was performed under the following conditions.
X-ray diffraction measurement apparatus: X-Pert PRO type X-ray source manufactured by Spectris: Cu-Kα ray (wavelength 1.54 mm), output: 40 KV 40 mA, operation axis: θ / 2θ, measurement mode: Continuous, measurement range: 2θ = 5 to 80 °, capture width: 0.01 °, scanning speed: 5.0 ° / min.

[Example 1]
MTR mixed fullerene (C ₆₀ : 50%, C ₇₀ : 40%, polymer fullerene: 10%) purchased from Tokyo Progress System was put in a small rotary kiln and heated to 950 ° C in a nitrogen atmosphere. At this temperature, the activation treatment was performed by holding for 10 minutes in an atmosphere of water vapor / nitrogen = 50/50 (volume ratio). Then, it was left to cool in a nitrogen atmosphere to produce porous carbon. The yield with respect to the carbonaceous material immediately before the activation of the obtained porous carbon was determined to be 83% by mass. The characteristics of the obtained porous carbon and the results of the adsorption test are shown in Table 1. The yield is defined by the following formula.
Yield (%) = 100 × (mass of porous carbon immediately after activation / mass of carbonaceous material immediately before activation)

[Example 2]
Fullerene-containing soot (C ₆₀ : 10% or more) purchased from Tokyo Progress System was put into a small rotary kiln to produce porous carbon in the same manner as in Example 1. The yield with respect to the carbonaceous material immediately before activation of the obtained porous carbon was determined and found to be 79% by mass. The characteristics of the obtained porous carbon and the results of the adsorption test are shown in Table 1.

FIG. 3 shows the results of X-ray diffraction measurement of fullerene-containing soot (C ₆₀ : product containing 10% or more) manufactured by Tokyo Progress Co., Ltd. Peaks derived from graphite are observed in the vicinity of 27 °, 44 °, and 55 °, peaks considered to be derived from fullerene C ₆₀ in the vicinity of 11 °, 17 °, and 21 °, and further, amorphous and amorphous. An increase in plateau-like baseline, which is thought to be derived from carbon, was observed.

[Example 3]
The fullerene-containing soot used in Example 2 was put in a box-type baking furnace, heated to 1400 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere, held at that temperature for 4 hours, and then allowed to cool. Porous carbon was produced. The yield of porous carbon after the heat treatment relative to the carbonaceous material before the heat treatment was 84% by mass. The characteristics of the obtained porous carbon and the results of the adsorption test are shown in Table 1.

[Example 4]
60 times the mass of toluene was added to the fullerene-containing soot used in Example 2, and after applying ultrasonic waves for 1 hour, the mixture was filtered. Further, the filtrate was washed with toluene until the color of the filtrate disappeared, and an extraction residue was obtained in which at least part of the fullerene was substantially extracted from the fullerene-containing soot with toluene at a yield of 90%. This was put into a small rotary kiln, heated to 950 ° C. under a nitrogen atmosphere, and then subjected to an activation treatment by holding at that temperature for 10 minutes in an atmosphere of water vapor / nitrogen = 50/50 (volume ratio). Then, it was left to cool in a nitrogen atmosphere to produce porous carbon. When the yield with respect to the carbonaceous material just before activation of the obtained porous carbon was calculated | required, it was 84 mass%. The characteristics of the obtained porous carbon and the results of the adsorption test are shown in Table 1.

FIG. 4 shows the result of X-ray diffraction measurement of the extraction residue obtained by substantially extracting at least a part of fullerene from the fullerene-containing soot using a solvent. From FIG. 4, it is recognized that the peak heights near 11 °, 17 °, and 21 ° considered to be derived from fullerene C ₆₀ are relatively lower than those of FIG. 3 compared with the peaks derived from graphite. It is done. From the results, obtained extracted residue, it is understood C ₆₀ as at least a part of fullerene from the fullerene-containing soot is one that is substantially extracted.

[Comparative Example 1]
Commercially available coconut shell steam activated activated carbon (Diasorb, carbon tech, BET specific surface area: 1150 m ² / g, average diameter 150 μm) was used as the adsorbent. Table 1 shows the characteristics of the activated carbon and the results of an adsorption test using the activated carbon.

[Comparative Example 2]
In order to reduce the amount of acidic functional groups on the surface in the same manner as in Example 7, alkali-activated material obtained by carbonizing a spherical phenol resin manufactured by Kanebo Co., Ltd. having an average diameter of 110 μm at 700 ° C. was used as an activation raw material. Heat treatment was performed at 900 ° C. for 2 hours. Table 1 shows the characteristics of the obtained activated carbon and the results of the adsorption test using the activated carbon.

From Table 1, the adsorbents of Examples 1 to 4 have a pore diameter of 100 μm or less, with respect to the total pore volume.
The pore volume ratio with a pore diameter of 20 to 100% was in the range of 5 to 50%, and the pore volume ratio with a pore diameter of 10 or less was 45% or more. From this result, it can be seen that the adsorbents of Examples 1 to 4 have specific pore volume characteristics as compared with conventional adsorbents such as Comparative Examples 1 and 2. In addition, the adsorbents of Examples 1 to 4 each had an excellent water flow rate of 48 (l / g) or more, and the water purification performance was extremely high.

  On the other hand, in the comparative example, the pore volume ratio of 10 mm or less effective for static adsorption force is as high as more than 80%, but the pore volume ratio of 20 mm to 100 mm effective for dynamic adsorption force is less than 10%. In addition, the amount of water that can be passed is considered to have decreased.

  The pore distribution of the porous carbon used in Example 1, Example 4, and Comparative Example 2 is shown in FIG. 1, and the cumulative pore volume is shown in FIG. 1 and 2, the porous carbon used in the present invention has a relatively small proportion of pores having a pore diameter of less than 20 mm compared with the conventional porous carbon, while the dynamic adsorption force It can be seen that the proportion of pores having an effective pore diameter of 20 to 100 mm increases.

  The adsorbent of the present invention is suitable for removing trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane, bromoform) or other organic chlorine compounds (trichloroethylene, trichloroethane, tetrachloroethylene, methylene chloride, etc.) in water, It is suitable for purification of drinking water such as tap water and well water, and is also considered to be applicable to purification of sewage and industrial wastewater. Moreover, the adsorbent of this invention can be used conveniently for a household faucet direct connection type water purifier cartridge, a commercial large column, etc., for example.

The graph which illustrates the pore distribution of porous carbon. The graph which shows the accumulation pore volume of porous carbon. 2 is an X-ray diffraction pattern of fullerene-containing soot used in the present invention. It is an X-ray diffraction pattern of an extraction residue obtained by substantially extracting at least a part of fullerene from a fullerene-containing soot used in the present invention using a solvent.

Claims (9)

For a pore volume with a pore diameter of 100 mm or less,
The pore volume ratio of the pore diameter of 20-100cm is 5-50%,
An adsorbent comprising porous carbon having a pore volume ratio of 45% or more with a pore diameter of 10 mm or less.   The adsorbent according to claim 1, wherein the pore volume ratio of the pore diameter of 10 mm or less is 85% or less.   The adsorbent according to claim 1 or 2, wherein a pore volume ratio of the pore diameter of 20 to 100% is 5 to 30%.   The adsorbent according to any one of claims 1 to 3, wherein a ratio of a pore volume having a pore diameter of 100 mm or less to a total pore volume of the porous carbon is 55 to 96%. The adsorbent according to claim 1, wherein the porous carbon has a BET specific surface area of 350 to 1450 m ² / g.   The porous carbon comprises at least one carbonaceous material selected from the group consisting of fullerene, fullerene-containing soot, and an extraction residue obtained by substantially extracting at least a part of fullerene from the fullerene-containing soot. The adsorbent according to any one of claims 1 to 5, which is obtained by activation.   The adsorbent according to claim 6, wherein the activation treatment is performed by bringing the carbonaceous material into contact with an oxidizing gas at 750 ° C or higher.   The adsorbent according to claim 6, wherein the activation treatment is performed by heat-treating the carbonaceous material to 750 ° C. or higher in an inert atmosphere. The adsorbent for water purification according to any one of claims 1 to 8.

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