WO2018116858A1

WO2018116858A1 - Active carbon and production method thereof

Info

Publication number: WO2018116858A1
Application number: PCT/JP2017/044096
Authority: WO
Inventors: 中野　智康; 弘和清水; 啓二堺
Original assignee: 株式会社アドール; ユニチカ株式会社; 大阪ガスケミカル株式会社
Priority date: 2016-12-19
Filing date: 2017-12-07
Publication date: 2018-06-28
Also published as: TW201831401A; JPWO2018116858A1; JP6379324B1

Abstract

Active carbon that has excellent dichloromethane absorption performance per unit of specific surface area is provided. Of the pore volume calculated by the QSDFT method, the pore volume A (cc/g) in this active carbon of pores less than or equal to 1.0 nm is greater than or equal to 0.35 cc/g, and, of the pore volume calculated by the QSDFT method, the pore volume B of pores with a pore diameter in the range 1.0-3.0 nm is 0.15-0.35 cc/g.

Description

Activated carbon and manufacturing method thereof

The present invention relates to activated carbon and a method for producing the same, and more particularly to activated carbon suitable for adsorbing dichloromethane in the gas phase and a method for producing the activated carbon.

Conventionally, there is known an adsorption removal technique in which components existing in a gas phase or a liquid phase are adsorbed by activated carbon and these components are removed. Conventionally, the adsorption removal technique using activated carbon is also used for solvent recovery from a gas containing an organic solvent.

Examples of activated carbon fibers having particularly excellent adsorption performance for organic compounds such as dichloromethane include a BET specific surface area of 700 to 1500 m ² / g, a total pore volume of 0.3 to 0.7 cc / g, and a pore diameter of 1 nm. An activated carbon fiber having a micropore pore volume (micropore) below of 95% or more of the total micropore pore volume and a moisture adsorption rate of 15% or less at a temperature of 25 ° C. and a relative humidity of 52% is known. (For example, refer to Patent Document 1). According to the document, when the BET specific surface area is less than 700 m ² / g, the adsorption area is too small and an organic compound such as dichloromethane having a boiling point in the range of −30 to 70 ° C. is not sufficiently adsorbed. There is a problem that if it exceeds 1500 m ² / g, the pores become large, so that there is a problem that organic compounds such as dichloromethane having a boiling point in the range of −30 to 70 ° C. are not sufficiently adsorbed. Yes. In addition, in this document, when the micropore volume having a pore diameter of 1 nm or less is less than 95% of the total micropore volume, the pores are too large and the boiling point is within the range of −30 to 70 ° C. For example, it is described that there is a problem that an organic compound such as dichloromethane is not sufficiently adsorbed. Furthermore, in this document, when the moisture adsorption rate at a temperature of 25 ° C. and a relative humidity of 52% exceeds 15%, water molecules are adsorbed first around the pores, and therefore, the pores contain organic compounds. It is described that there is a problem that the amount of adsorption is not adsorbed and decreases accordingly.

JP 2011-106051 A

The present inventors examined the equilibrium adsorption amount of activated carbon with dichloromethane, and it was found that the adsorption amount depends on the specific surface area, and the higher the specific surface area, the higher the adsorption amount. However, it is not necessary to simply set the surface area to a high specific surface area. For example, when the equilibrium equilibrium adsorption amount per unit specific surface area was evaluated, it was found that there was a difference in adsorption efficiency due to the difference in pore structure. That is, when the specific surface area is simply increased, the amount of adsorbed dichloromethane increases as the amount of pores increases, but the adsorption efficiency is considered to deteriorate due to the overall increase in pores.

The main object of the present invention is to solve the above problems and provide an activated carbon excellent in dichloromethane adsorption performance per unit specific surface area and a method for producing the same.

In order to solve the above problems, the present inventors examined the realization of a pore structure suitable for adsorption of low-boiling organic compounds such as dichloromethane. Specifically, it is necessary to maintain or increase the micropore volume with a pore diameter of 1 nm or less, which is considered suitable for adsorption of low-boiling organic compounds such as dichloromethane, and to prevent the influence of coexisting moisture. It was considered effective to provide an appropriate amount of holes.

In addition, it is thought that moderately developing such relatively large pores plays a role in assisting diffusion of dichloromethane molecules in the pores, and is effective not only in equilibrium adsorption but also in aeration treatment. It was.

However, it has been very difficult to control the pores so that another pore having a relatively large pore diameter is provided while maintaining the pore volume of 1 nm or less. That is, for example, in the activated carbon fiber of Patent Document 1, when the activation is further advanced, the activation proceeds so that the pores expand as a whole, so that there is a problem that small micropores of 1 nm or less effective for adsorption cannot be maintained. occured.

Therefore, as a result of further intensive studies by the present inventors, it was assumed that a specific amount of an yttrium compound was contained as an activated carbon precursor, and activation was performed using carbon dioxide as an activation gas. While maintaining, it succeeded in providing an appropriate amount of another pore having a relatively large pore diameter exceeding 1 nm. Furthermore, it discovered that the activated carbon obtained in this way was excellent in the dichloromethane adsorption | suction performance per unit specific surface area.

The present invention is an invention that has been completed through further studies based on these findings.

That is, this invention provides the invention of the aspect hung up below.
Item 1. Of the pore volumes calculated by the QSDFT method, the pore volume A (cc / g) of 1.0 nm or less is 0.35 cc / g or more,
And the activated carbon whose pore volume B of the pore diameter of the range of 1.0 nm or more and 3.0 nm or less is 0.15 cc / g or more and 0.35 cc / g or less among the pore volumes calculated by the QSDFT method.
Item 2. Item 2. The activated carbon according to Item 1, wherein the pore volume (cc / g) of 3.0 nm or more is 0.01 cc / g or less among the pore volumes calculated by the QSDFT method.
Item 3. Item 3. The activated carbon according to

Item

1 or 2, wherein the ratio of the pore volume B to the pore volume A (pore volume B / pore volume A) is 0.3 to 0.8.
Item 4. Item 1. The specific surface area is 1300 m ² / g or more and 2000 m ² / g or less, and among the pore volumes calculated by the QSDFT method, the total pore volume is 0.5 cc / g or more and 0.8 cc / g or less. The activated carbon according to any one of items 1 to 3.
Item 5. Item 5. The activated carbon according to any one of Items 1 to 4, wherein the dichloromethane equilibrium adsorption amount per unit specific surface area is 0.045 mass% · g / m ² or more.
Item 6. Item 6. The activated carbon according to any one of Items 1 to 5, wherein the activated carbon is fibrous activated carbon.
Item 7. Item 7. The activated carbon according to any one of Items 1 to 6, which is used for adsorbing dichloromethane in a gas phase.
Item 8. Item 7. The method for producing activated carbon according to Item 1 to 6, comprising a step of activating an activated carbon precursor containing an yttrium compound at a temperature of 600 to 1200 ° C. in an atmosphere having a CO ₂ concentration of 90% by volume or more. Production method.
Item 9. Item 8. A dichloromethane adsorbent comprising the activated carbon according to any one of Items 1 to 7.
Item 10. Item 8. A method for adsorbing and removing dichloromethane using the activated carbon according to any one of Items 1 to 7.

According to the activated carbon of the present invention, among the pore volumes calculated by the QSDFT method, the pore volume A (cc / g) of 1.0 nm or less is 0.35 cc / g or more, and calculated by the QSDFT method. Since the pore volume B having a pore diameter in the range of 1.0 nm to 3.0 nm is 0.15 cc / g to 0.35 cc / g, dichloromethane per unit specific surface area Excellent adsorption performance. Moreover, according to the method for producing activated carbon of the present invention, activated carbon excellent in dichloromethane adsorption performance per unit specific surface area can be produced. Therefore, the activated carbon of the present invention can be suitably used for solvent recovery.

2 is a graph showing the pore size distribution calculated by the QSDFT method for activated carbon of Example 1. FIG. It is a graph which shows the pore size distribution calculated by the QSDFT method of the activated carbon of Example 2. It is a graph which shows the pore diameter distribution calculated by the QSDFT method of the activated carbon of Example 3. It is a graph which shows the pore diameter distribution calculated by the QSDFT method of the activated carbon of Example 4. 6 is a graph showing a pore size distribution calculated by the QSDFT method of activated carbon of Comparative Example 1. It is a graph which shows the pore size distribution calculated by the QSDFT method of the activated carbon of the comparative example 2. It is a graph which shows the pore size distribution computed by the QSDFT method of the activated carbon of the comparative example 3. It is a graph which shows the pore size distribution calculated by the QSDFT method of the activated carbon of the comparative example 4.

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

The activated carbon of the present invention has a pore volume A (cc / g) of 1.0 nm or less of the pore volume calculated by the QSDFT method of 0.35 cc / g or more, and is calculated by the QSDFT method. Among the pore volumes, the pore volume B having a pore diameter in the range of 1.0 nm to 3.0 nm is 0.15 cc / g to 0.35 cc / g.

In the present invention, the QSDFT method (quenched solid density functional method) refers to a pore size analysis of geometrically and chemically irregular microporous and mesoporous carbon, from about 0.5 nm to about 40 nm. This is an analysis method that can calculate the pore size distribution of the. In the QSDFT method, the influence of the roughness and nonuniformity of the pore surface is clearly taken into account, so that the accuracy of the pore diameter distribution analysis is greatly improved. In the present invention, measurement of nitrogen adsorption isotherm and pore size distribution analysis by QSDFT method are performed using “AUTOSORB-1-MP” manufactured by Quantachrome. By applying the N2 at 77K on carbon [slit pore, QSDFT equilibium model] as the calibration model to the nitrogen desorption isotherm measured at a temperature of 77 K, the pore size distribution is calculated to obtain a fine pore size range. The pore volume can be calculated.

The activated carbon of the present invention has a pore volume A having a pore diameter in the range of 1.0 nm or less of the pore volume calculated by the QSDFT method of 0.35 cc / g or more, and dichloromethane adsorption performance per unit specific surface area. Is more preferably 0.35 cc / g or more and 0.60 cc / g or less, and more preferably 0.40 cc / g or more and 0.50 cc / g or less.

In the activated carbon of the present invention, the pore volume B having a pore diameter in the range of 1.0 nm to 3.0 nm is 0.15 cc / g to 0.35 cc / g in the pore volume calculated by the QSDFT method. From the viewpoint of further improving the dichloromethane adsorption performance per unit specific surface area, it is preferably 0.20 cc / g or more and 0.35 cc / g or less, more preferably 0.30 cc / g or more and 0.35 cc / g or less. .

The activated carbon of the present invention has a pore volume D having a pore diameter in the range of 3.0 nm or more among the pore volumes calculated by the QSDFT method from the viewpoint of further improving the dichloromethane adsorption performance per unit specific surface area. Is preferably 0.1 cc / g or less, and more preferably 0.01 cc / g or less.

From the same viewpoint, the activated carbon of the present invention has a pore volume C having a pore diameter in the range of 1.0 nm or more and 2.0 nm or less, among pore volumes calculated by the QSDFT method, of 0.10 cc / g or more and 0.0. 30 cc / g or less is preferable, and 0.20 cc / g or more and 0.30 cc / g or less is more preferable. Moreover, the pore volume of the pore diameter in the range of 2.0 nm or more and 3.0 nm or less is preferably 0.01 cc / g or more and 0.05 cc / g or less. Moreover, the pore volume of the pore diameter in the range of 1.5 nm or less is preferably 0.5 cc / g or more and 0.7 cc / g or less. Further, the pore volume of the pore diameter in the range of 1.5 nm to 2.5 nm is preferably 0.03 cc / g or more and 0.15 cc / g or less, more preferably 0.07 cc / g or more and 0.15 cc / g or less. . Further, the pore volume having a pore diameter in the range of 2.5 nm or more is preferably 0.03 cc / g or less.

The activated carbon of the present invention has a ratio of the pore volume B to the pore volume A (pore volume B / pore volume A) from the viewpoint of further improving the dichloromethane adsorption performance per unit specific surface area. It is preferably 0.3 to 0.8, and more preferably 0.6 to 0.8.

From the same viewpoint, the activated carbon of the present invention is 1.0 nm or less with respect to the pore volume E (that is, micropore volume) having a pore diameter in the range of 2.0 nm or less among the pore volumes calculated by the QSDFT method. The ratio (A / E) of the pore volume A having a pore diameter in the range is preferably 0.94 or less, more preferably 0.5 to 0.8, and more preferably 0.55 to 0.7. It is particularly preferred.

Activated carbon of the present invention, the specific surface area of the activated carbon (value measured by the BET method using nitrogen as the adsorbed substance (1-point ^{method)), 1000 ~ 2000m 2 /} g , preferably about 1300 ~ 2000 m ² / g, more preferably about 1400 to 1800 m ² / g, particularly preferably about 1600 to 1800 m ² / g. Further, the total pore volume of the activated carbon calculated by the QSDFT method is about 0.45 to 1.50 cc / g, more preferably about 0.50 to 0.8 cc / g.

Further, from the viewpoint of making the dichloromethane adsorption performance per unit specific surface area more excellent, in the activated carbon of the present invention, the ratio of the pore volume A in the total pore volume (100%) is preferably 50. About 75%, more preferably about 53-60%. From the same viewpoint, the proportion of the pore volume B in the total pore volume (100%) is preferably about 25 to 50%, more preferably about 40 to 47%.

As will be described later, in the production method of the present invention, the main raw material of the activated carbon precursor (that is, the raw material from which the activated carbon of the present invention is derived) is not particularly limited. For example, an infusible or carbonized organic material, phenol Examples of the organic material include polyacrylonitrile, pitch, polyvinyl alcohol, and cellulose. Among these, the activated carbon of the present invention is preferably derived from pitch, and more preferably derived from coal pitch.

For the activated carbon of the present invention, one containing an yttrium compound as an activated carbon precursor is used in order to obtain the specific pore size distribution. And the activated carbon of this invention may contain the yttrium single-piece | unit and / or yttrium compound originating in the yttrium compound contained in an activated carbon precursor. The ratio (total) of the mass of the yttrium simple substance and the yttrium compound contained in the activated carbon in the total mass of the activated carbon of the present invention is, for example, 0.01 to 5.0% by mass, and 0.05 to 3 0.0% by mass is preferable, and 0.05 to 0.3% by mass is particularly preferable. The above ratio is a ratio in terms of yttrium element (that is, yttrium content) measured by an ICP emission spectroscopic analyzer (model 715-ES manufactured by Varian).

The activated carbon of the present invention has a pore volume A (cc / g) of 1.0 nm or less of the pore volume calculated by the QSDFT method of 0.35 cc / g or more, and is calculated by the QSDFT method. Since the pore volume B of the pore diameter in the range of 1.0 nm to 3.0 nm is 0.15 cc / g to 0.35 cc / g, the dichloromethane adsorption performance per unit specific surface area Excellent. Specifically, the dichloromethane adsorption performance (equilibrium adsorption amount (% by mass)) provided by the activated carbon of the present invention includes, for example, 60% by mass or more, preferably 65% by mass or more, more preferably 75% by mass or more, Especially preferably, 80 mass% or more is mentioned. In the present invention, the dichloromethane adsorption performance is measured as follows. That is, the activated carbon sample is dried with a dryer at 110 ° C. for 12 hours, cooled with a desiccator, and 0.5 g is quickly measured and filled into a U-shaped tube. Next, the adsorption operation is performed by blowing dry air at a flow rate of 500 ml / min into dichloromethane (special grade reagent, containing 0.5% of methanol in the stabilizer) in a constant temperature bath at 28 ° C. and introducing it into the U-shaped tube. . The equilibrium point is calculated when the mass increase of the activated carbon stops, and the equilibrium adsorption amount is calculated by the following equation.
Equilibrium adsorption amount (% by mass) = mass increase / active carbon mass x 100

Then, as the dichloromethane adsorption performance per unit specific surface area activated carbon of the present invention comprises, it includes 0.045 wt% · g / m ^2, 0.046 wt% · g / m ² are preferably exemplified, 0. More preferred is 046 to 0.055 mass% · g / m ² . In the present invention, the dichloromethane equilibrium adsorption amount per unit specific surface area of activated carbon is calculated by dividing the dichloromethane adsorption performance determined as described above by the specific surface area (m ² / g) of the activated carbon.

Although the form of the activated carbon of this invention is not specifically limited, For example, granular activated carbon, powdered activated carbon, fibrous activated carbon, etc. are mentioned. From the viewpoint of further improving the adsorption rate of dichloromethane, it is more preferable to use fibrous activated carbon that is fibrous. The average fiber diameter of the fibrous activated carbon is preferably 30 μm or less, more preferably about 5 to 20 μm. In addition, the average fiber diameter in this invention is the value measured with the image processing fiber diameter measuring apparatus (based on JISK1477). Examples of the particle sizes of the granular activated carbon and the powdered activated carbon include an integrated volume percentage D ₅₀ measured by a laser diffraction / scattering method of 0.01 to 5 mm.

The activated carbon of the present invention can be used either in the gas phase or in the liquid phase. In particular, the activated carbon of the present invention is suitably used for adsorbing dichloromethane in the gas phase.

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

The method for producing activated carbon of the present invention includes a step of activating an activated carbon precursor containing an yttrium compound at a temperature of 600 to 1200 ° C. in an atmosphere having a CO ₂ concentration of 90% by volume or more. Thereby, for the first time, while maintaining the volume of pores of 1 nm or less, an appropriate amount of pores having a relatively large pore diameter of 1.0 to 3.0 nm can be provided, and the activated carbon of the present invention can be obtained. . On the other hand, when the activation gas is water vapor widely used in the past, it is difficult to maintain pores of 1 nm or less. Further, when the activated carbon precursor does not contain an yttrium compound, it is difficult to set the volume of pores having a relatively large pore diameter of 1.0 to 3.0 nm to a specific amount.

In the production method of the present invention, the main raw material for the activated carbon precursor is not particularly limited. For example, an infusible or carbonized organic material, an infusible resin such as a phenol resin, and the like can be cited. Examples of the organic material include polyacrylonitrile, pitch, polyvinyl alcohol, and cellulose. From the viewpoint of theoretical carbonization yield at the time of carbonization, pitch is preferable, and coal pitch is particularly preferable among pitches.

In the production method of the present invention, the yttrium content of the activated carbon precursor is preferably 0.01 to 5.0% by mass, more preferably 0.05 to 1.0% by mass, and still more preferably 0.05 to 0.5 mass% is mentioned. Yttrium can be contained by mixing yttrium alone or an yttrium compound with a raw material. Examples of the yttrium compound include yttrium as a constituent metal element, metal oxide, metal hydroxide, metal halide, inorganic metal compound such as metal sulfate, salt of organic acid and metal such as acetic acid, organometallic compound, etc. Is mentioned. Examples of the organometallic compound include metal acetylacetonate and aromatic metal compounds.

In the production method of the present invention, the activation atmosphere has a CO ₂ concentration of 90% by volume or more, preferably 95% by volume or more, more preferably 99% by volume or more.

In the activation atmosphere, other components other than CO ₂ include N ₂ , O ₂ , H ₂ , H ₂ O, and CO.

In the production method of the present invention, the activation ambient temperature is usually about 600 to 1200 ° C., preferably about 800 to 1000 ° C., more preferably about 900 to 1000 ° C. Moreover, what is necessary is just to adjust activation time so that it may become predetermined | prescribed pore diameter distribution according to the main raw material of an activated carbon precursor. For example, when a pitch having a softening point of 275 ° C. to 288 ° C. is used as the main raw material of the activated carbon precursor, the activation ambient temperature is 900 to 1000 ° C., the activation time is 10 to 80 minutes, and more preferably 60 to 80 The activation can be mentioned as a part.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples.

Each Example and Comparative Example were evaluated by the following methods.
(1) Yttrium content (mass%) of infusible pitch fiber (activated carbon precursor)
The pitch fiber was incinerated, the ash was dissolved in an acid, and the ratio in terms of yttrium element measured by an ICP emission spectroscopic analyzer (model 715-ES manufactured by Varian) was defined as the yttrium content.

(2) Metal content of active carbon (mass%)
The yttrium content was defined as the ratio of yttrium element measured by dissolving fibrous activated carbon in an acid and measuring with an ICP emission spectroscopic analyzer (model 715-ES manufactured by Varian).

(3) Pore volume (cc / g), specific surface area (m ² / g), fiber diameter of fibrous activated carbon (μm)
The pore physical properties were measured by nitrogen adsorption isotherm at 77K using “AUTOSORB-1-MP” manufactured by Quantachrome. The specific surface area was calculated from the measurement point of relative pressure 0.1 by the BET method. Pore volume in the pore diameter range described total pore volume and Table 1, compared the measured nitrogen desorption isotherm, by applying _{N 2 at 77K on carbon [slit} pore, QSDFT equilibrium model] as Calculation model Analysis was performed by calculating the pore size distribution. Specifically, the pore volume in each pore diameter range described in Table 1 is a reading value of a graph showing the pore diameter distribution shown in FIGS. 1 to 8, or a value calculated from the reading value. More specifically, the pore volume having a pore diameter of 0.65 nm or less is a reading value of Cumulative Pore Volume (cc / g) when the horizontal axis of the graph indicating the pore diameter distribution is Por Width 0.65 nm. Similarly, a pore volume having a pore diameter of 0.8 nm or less, a pore volume A having a pore diameter of 1.0 nm or less, a pore volume having a pore diameter of 1.5 nm or less, a pore volume E having a pore diameter of 2.0 nm or less, A pore volume having a pore diameter of 2.5 nm or less and a pore volume having a pore diameter of 3.0 nm or less were obtained. The pore volume with a pore diameter of 2.5 nm or more was calculated by subtracting the pore volume with a pore diameter of 2.5 nm or less from the total pore volume T obtained by the QSDFT method. Similarly, the pore volume D having a pore diameter of 3.0 nm or more was calculated by subtracting the pore volume having a pore diameter of 3.0 nm or less from the total pore volume T obtained by the QSDFT method. The pore volume in the pore diameter range of 0.65 to 0.8 nm was calculated by subtracting the pore volume having the pore diameter of 0.65 nm or less from the pore volume having the pore diameter of 0.8 nm or less. The pore volume within the pore diameter range of 1.0 nm to 1.5 nm was calculated by subtracting the pore volume A having a pore diameter of 1.0 nm or less from the pore volume having a pore diameter of 1.5 nm or less. The pore volume C in the pore diameter range of 1.0 nm to 2.0 nm was calculated by subtracting the pore volume A having a pore diameter of 1.0 nm or less from the pore volume E having a pore diameter of 2.0 nm or less. The pore volume B in the pore diameter range of 1.0 nm to 3.0 nm was calculated by subtracting the pore volume A having a pore diameter of 1.0 nm or less from the pore volume having a pore diameter of 3.0 nm or less. The pore volume in the range of the pore diameter of 1.5 nm to 2.0 nm was calculated by subtracting the pore volume having the pore diameter of 1.5 nm or less from the pore volume E having the pore diameter of 2.0 nm or less. The pore volume in the range of the pore diameter of 1.5 nm to 2.5 nm was calculated by subtracting the pore volume of the pore diameter of 1.5 nm or less from the pore volume of the pore diameter of 2.5 nm or less. The pore volume within the pore diameter range of 2.0 nm to 2.5 nm was calculated by subtracting the pore volume E having a pore diameter of 2.0 nm or less from the pore volume having a pore diameter of 2.5 nm or less. The pore volume in the pore diameter range of 2.0 nm to 3.0 nm was calculated by subtracting the pore volume E having a pore diameter of 2.0 nm or less from the pore volume having a pore diameter of 3.0 nm or less. The pore volume in the range of 2.5 nm to 3.0 nm was calculated by subtracting the pore volume having a pore diameter of 2.5 nm or less from the pore volume having a pore diameter of 3.0 nm or less.

(4) Fiber diameter of fibrous activated carbon (μm)
It measured with the image processing fiber diameter measuring apparatus (based on JISK1477).

(5) Dichloromethane equilibrium adsorption performance (mass%)
The activated carbon sample was dried overnight with a dryer at 110 ° C., cooled with a desiccator, and 0.5 g was quickly weighed and filled into a U-shaped tube. Next, adsorption operation is performed by blowing dry air into dichloromethane (special grade reagent, containing 0.5% methanol in the stabilizer) at a flow rate of 500 ml / min in a constant temperature bath at 28 ° C. and introducing it into a U-tube. It was. Equilibrium adsorption amount was calculated by taking the time when the mass increase of the activated carbon stopped as an equilibrium state.
Equilibrium adsorption amount (%) = mass increase / activated carbon mass × 100

Example 1
As an organic material, a mixture of 0.3 parts by mass of trisacetylacetonatoyttrium with 100 parts by mass of a granular coal pitch having a softening point of 280 ° C is supplied to a melt extruder and melt-mixed at a melting temperature of 320 ° C. Then, pitch fibers were obtained by spinning at a discharge rate of 20 g / min. The obtained pitch fiber was heated from normal temperature to 354 ° C. in air at a rate of 1 to 30 ° C./min for 54 minutes to effect infusibilization to obtain an activated carbon precursor as an infusible pitch fiber. In the activated carbon precursor, the content of yttrium and the yttrium compound (in terms of yttrium element) was 0.06% by mass.

The activated carbon precursor obtained was activated by continuously introducing a gas having a CO ₂ concentration of 100% by volume into an activation furnace and heat-treating it at an ambient temperature of 950 ° C. for 67 minutes to obtain activated carbon of Example 1. It was. The obtained activated carbon has a pore volume A having a pore diameter in the range of 1.0 nm or less of 0.42 cc / g, and a pore volume B having a pore diameter in the range of 1.0 to 3.0 nm of 0.31 cc / g. g, The content of yttrium was 0.17% by mass, and the average fiber diameter was 16.8 μm.

(Example 2)
As an organic material, a mixture of 0.3 parts by mass of trisacetylacetonatoyttrium with 100 parts by mass of a granular coal pitch having a softening point of 280 ° C is supplied to a melt extruder and melt-mixed at a melting temperature of 320 ° C. Then, pitch fibers were obtained by spinning at a discharge rate of 20 g / min. The obtained pitch fiber was heated from normal temperature to 354 ° C. in air at a rate of 1 to 30 ° C./min for 54 minutes to effect infusibilization to obtain an activated carbon precursor as an infusible pitch fiber. In the activated carbon precursor, the yttrium and yttrium compound content (in terms of yttrium element) was 0.06 parts by mass.

The activated carbon precursor obtained was activated by continuously introducing a gas having a CO ₂ concentration of 100% by volume into an activation furnace and heat treating it at an atmospheric temperature of 950 ° C. for 70 minutes to obtain activated carbon of Example 2. It was. The obtained activated carbon has a pore volume A having a pore diameter in the range of 1.0 nm or less of 0.43 cc / g, and a pore volume B having a pore diameter in the range of 1.0 to 3.0 nm of 0.34 cc / g. g, The content of yttrium was 0.18% by mass, and the average fiber diameter was 16.8 μm.

(Example 3)
As an organic material, a mixture of 0.3 parts by mass of trisacetylacetonatoyttrium with 100 parts by mass of a granular coal pitch having a softening point of 280 ° C is supplied to a melt extruder and melt-mixed at a melting temperature of 320 ° C. Then, pitch fibers were obtained by spinning at a discharge rate of 20 g / min. The obtained pitch fiber was heated from normal temperature to 354 ° C. in air at a rate of 1 to 30 ° C./min for 54 minutes to effect infusibilization to obtain an activated carbon precursor as an infusible pitch fiber. In the activated carbon precursor, the content of yttrium and the yttrium compound (in terms of yttrium element) was 0.06% by mass.

The activated carbon precursor obtained was activated by continuously introducing a gas having a CO ₂ concentration of 100% by volume into an activation furnace and heat-treating it at an atmospheric temperature of 950 ° C. for 65 minutes to obtain activated carbon of Example 3. It was. The obtained activated carbon has a pore volume A having a pore diameter in the range of 1.0 nm or less of 0.41 cc / g, and a pore volume B having a pore diameter in the range of 1.0 to 3.0 nm of 0.27 cc / g. g, The content of yttrium was 0.15% by mass, and the average fiber diameter was 18.2 μm.

Example 4
As an organic material, a mixture of 0.3 parts by mass of trisacetylacetonatoyttrium with 100 parts by mass of a granular coal pitch having a softening point of 280 ° C is supplied to a melt extruder and melt-mixed at a melting temperature of 320 ° C. Then, pitch fibers were obtained by spinning at a discharge rate of 20 g / min. The obtained pitch fiber was heated from normal temperature to 354 ° C. in air at a rate of 1 to 30 ° C./min for 54 minutes to effect infusibilization to obtain an activated carbon precursor as an infusible pitch fiber. In the activated carbon precursor, the yttrium and yttrium compound content (in terms of yttrium element) was 0.06 parts by mass.

Give the resulting activated carbon precursor, CO ₂ concentration is continuously introduced into the activation reactor 100 volume% of a gas, subjected to activation by heat treatment for 55 minutes at ambient temperature 950 ° C., activated carbon of Example 4 It was. The obtained activated carbon has a pore volume A having a pore diameter in the range of 1.0 nm or less of 0.41 cc / g, and a pore volume B having a pore diameter in the range of 1.0 to 3.0 nm of 0.27 cc / g. g, The content of yttrium was 0.14% by mass, and the average fiber diameter was 18.4 μm.

(Comparative Example 1)
As an organic material, granular coal pitch having a softening point of 280 ° C. was supplied to a melt extruder, melted and mixed at a melting temperature of 320 ° C., and spun at a discharge rate of 20 g / min to obtain pitch fibers. The obtained pitch fiber was heated from normal temperature to 354 ° C. in air at a rate of 1 to 30 ° C./min for 54 minutes to effect infusibilization to obtain an activated carbon precursor as an infusible pitch fiber. In the activated carbon precursor, the yttrium content was 0% by mass.

The activated carbon precursor obtained was activated by continuously introducing a gas having an H ₂ O concentration of 100% by volume into an activation furnace and heat treating it at an ambient temperature of 875 ° C. for 25 minutes. Obtained. The obtained activated carbon has a pore volume A having a pore diameter in the range of 1.0 nm or less of 0.31 cc / g, and a pore volume B having a pore diameter in the range of 1.0 to 3.0 nm of 0.00 cc / g. g, The content of yttrium was 0% by mass, and the average fiber diameter was 16.8 μm.

(Comparative Example 2)
As an organic material, granular coal pitch having a softening point of 280 ° C. was supplied to a melt extruder, melted and mixed at a melting temperature of 320 ° C., and spun at a discharge rate of 20 g / min to obtain pitch fibers. The obtained pitch fiber was heated from normal temperature to 354 ° C. in air at a rate of 1 to 30 ° C./min for 54 minutes to effect infusibilization to obtain an activated carbon precursor as an infusible pitch fiber. In the activated carbon precursor, the yttrium content was 0% by mass.

The activated carbon precursor obtained was activated by continuously introducing a gas having an H ₂ O concentration of 100% by volume into an activation furnace and heat treating it at an ambient temperature of 875 ° C. for 40 minutes. Obtained. The obtained activated carbon has a pore volume A having a pore diameter in the range of 1.0 nm or less of 0.40 cc / g, and a pore volume B having a pore diameter in the range of 1.0 to 3.0 nm of 0.08 cc / g. g, The content of yttrium was 0% by mass, and the average fiber diameter was 16.7 μm.

(Comparative Example 3)
As an organic material, a mixture of 1.3 parts by mass of trisacetylacetonatoyttrium with 100 parts by mass of a granular coal pitch having a softening point of 280 ° C. is supplied to a melt extruder and melt-mixed at a melting temperature of 320 ° C. Then, pitch fibers were obtained by spinning at a discharge rate of 20 g / min. The obtained pitch fiber was heated from normal temperature to 354 ° C. in air at a rate of 1 to 30 ° C./min for 54 minutes to effect infusibilization to obtain an activated carbon precursor as an infusible pitch fiber. In the activated carbon precursor, the content of yttrium and the yttrium compound (in terms of yttrium element) was 0.25 parts by mass.

The activated carbon precursor obtained was activated by continuously introducing a gas having an H ₂ O concentration of 100% by volume into an activation furnace and heat-treating it at an ambient temperature of 900 ° C. for 20 minutes. Obtained. The obtained activated carbon has a pore volume A having a pore diameter in the range of 1.0 nm or less of 0.24 cc / g, and a pore volume B having a pore diameter in the range of 1.0 to 3.0 nm of 0.28 cc / g. g, The content of yttrium was 0.66% by mass, and the average fiber diameter was 16.5 μm.

(Comparative Example 4)
As an organic material, a mixture of 1.3 parts by mass of trisacetylacetonatoyttrium with 100 parts by mass of a granular coal pitch having a softening point of 280 ° C. is supplied to a melt extruder and melt-mixed at a melting temperature of 320 ° C. Then, pitch fibers were obtained by spinning at a discharge rate of 20 g / min. The obtained pitch fiber was heated from normal temperature to 354 ° C. in air at a rate of 1 to 30 ° C./min for 54 minutes to effect infusibilization to obtain an activated carbon precursor as an infusible pitch fiber. In the activated carbon precursor, the content of yttrium and the yttrium compound (in terms of yttrium element) was 0.25 parts by mass.

The activated carbon precursor obtained was activated by continuously introducing a gas having an H ₂ O concentration of 100% by volume into an activation furnace and heat treating it at an ambient temperature of 900 ° C. for 25 minutes. Obtained. The obtained activated carbon has a pore volume A having a pore diameter in the range of 1.0 nm or less of 0.20 cc / g, and a pore volume B having a pore diameter in the range of 1.0 to 3.0 nm of 0.39 cc / g. g, The content of yttrium was 0.83% by mass, and the average fiber diameter was 15.8 μm.

The physical properties of the obtained activated carbon are shown in Table 1. 1 to 8 show pore size distribution diagrams calculated by the QSDFT method for the activated carbons of Examples 1 to 4 and Comparative Examples 1 to 4. FIG.

As is apparent from Table 1, the activated carbons of Examples 1 to 4 have a pore volume A (cc / g) of 1.05 nm or less of the pore volume calculated by the QSDFT method of 0.35 cc / g or more. In addition, among the pore volumes calculated by the QSDFT method, the pore volume B having a pore diameter in the range of 1.0 nm to 3.0 nm is 0.15 cc / g to 0.35 cc / g. Therefore, the dichloromethane adsorption performance per unit specific surface area was excellent.

In particular, the activated carbons of Examples 1 to 3 have a pore volume A (cc / g) of 1.0 nm or less among the pore volumes calculated by the QSDFT method of 0.40 cc / g or more and 0.50 cc / g or less. In addition, among the pore volumes calculated by the QSDFT method, the pore volume B having a pore diameter in the range of 1.0 nm to 3.0 nm is 0.20 cc / g to 0.35 cc / g. Since the ratio of the pore volume B to the pore volume A (pore volume B / pore volume A) is 0.6 to 0.8, the dichloromethane adsorption performance per unit specific surface area is particularly good. It was excellent.

On the other hand, the activated carbon of Comparative Example 1 has a pore volume A (cc / g) of 1.0 nm or less, less than 0.35 cc / g, and a pore diameter in the range of 1.0 nm or more and 3.0 nm or less. Since the volume B was less than 0.20 cc / g, the dichloromethane adsorption performance per unit specific surface area was inferior.

The activated carbon of Comparative Example 2 was inferior in dichloromethane adsorption performance per unit specific surface area because the pore volume B of pore diameters in the range of 1.0 nm to 3.0 nm was less than 0.20 cc / g. there were.

The activated carbon of Comparative Example 3 was inferior in dichloromethane adsorption performance per unit specific surface area because the pore volume A (cc / g) of 1.0 nm or less was less than 0.35 cc / g.

In the activated carbon of Comparative Example 4, the pore volume A (cc / g) of 1.0 nm or less is less than 0.35 cc / g, and the pore volume B has a pore diameter in the range of 1.0 nm or more and 3.0 nm or less. Was over 0.35 cc / g, the dichloromethane adsorption performance per unit specific surface area was poor.

Claims

Of the pore volumes calculated by the QSDFT method, the pore volume A (cc / g) of 1.0 nm or less is 0.35 cc / g or more,
And the activated carbon whose pore volume B of the pore diameter of the range of 1.0 nm or more and 3.0 nm or less is 0.15 cc / g or more and 0.35 cc / g or less among the pore volumes calculated by the QSDFT method.
The activated carbon according to claim 1, wherein the pore volume (cc / g) of 3.0 nm or more among the pore volumes calculated by the QSDFT method is 0.01 cc / g or less.
The activated carbon according to claim 1 or 2, wherein a ratio of the pore volume B to the pore volume A (pore volume B / pore volume A) is 0.3 to 0.8.
The specific surface area is 1300 m 2 / g or more and 2000 m 2 / g or less, and among the pore volumes calculated by the QSDFT method, the total pore volume is 0.5 cc / g or more and 0.8 cc / g or less. The activated carbon according to any one of 1 to 3.
The activated carbon according to any one of claims 1 to 4, wherein the dichloromethane equilibrium adsorption amount per unit specific surface area is 0.045 mass% · g / m 2 or more.
The activated carbon according to any one of claims 1 to 5, wherein the activated carbon is a fibrous activated carbon.
The activated carbon according to any one of claims 1 to 6, which is used for adsorbing dichloromethane in a gas phase.
The method for producing activated carbon according to any one of claims 1 to 6, comprising a step of activating the activated carbon precursor containing an yttrium compound at a temperature of 600 to 1200 ° C in an atmosphere having a CO 2 concentration of 90% by volume or more. Manufacturing method.
An adsorbent for dichloromethane comprising the activated carbon according to any one of claims 1 to 7.
A method for adsorbing and removing dichloromethane using the activated carbon according to any one of claims 1 to 7.