JPH044040A - Molded adsorbent and its production - Google Patents

Abstract

PURPOSE:To obtain a molded adsorbent having high bulk density and high specified surface area by molding a compounded material of fibrous activated carbon and a specified binder and heating the molded body under pressure. CONSTITUTION:Fibrous activated carbon obtained from the source material such as coal pitch, oil pitch, or the like, by 100 pts.wt. and a binder such as infusibilized hot-melt fiber, infusibilized carbon fiber, thermosetting type fiber, etc., by 2-40 pts.wt. are compounded and molded. Then, this molded body is heated under pressure of 30-1000kg/cm<2>.G at 500-1500 deg.C. The obtd. molded adsorbent has the bulk density as high as >=0.4g/cc and large specified surface area. Thus, the adsorbent is suitable for electrodes of electric two-layer capacitor, cartridges of water purifier, etc.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a shaped adsorbent and a method for manufacturing the same.

In this specification, "parts" means "parts by weight."

In recent years, fibrous activated carbon has been used as a new type of adsorbent. Since it is difficult to handle fibrous activated carbon as an adsorbent as raw cotton, it is used after being processed into forms such as felt, paper, nicum, and paper-like structures.

However, products having such a shape have a low bulk density, so although the specific surface area per product weight is large, the product has the disadvantage that the specific surface area per volume is low. For example, the bulk density of various products according to the prior art is as follows.

*Felt-like...about 0.05g/cc.

*Paper-like...about 0.1g/cc.

*Honeycomb shape...O/15g/cc approx.

*Molded article with papermaking structure...approximately 0.2 g/cc.

On the other hand, although granular activated carbon has a small specific surface area per weight, it has a high bulk density of about 0.5 g/cc, and therefore has a high specific surface area per volume compared to fibrous activated carbon.

Means for Solving the Problems In view of the current state of the technology as described above, the present inventor has conducted repeated research to obtain a shaped adsorbent with high bulk density and high specific surface area made of fibrous activated carbon. It has been found that this objective can be achieved if a blend of activated carbon and certain binders is shaped and heated under pressure.

That is, the present invention provides the following shaped adsorbent and its manufacturing method: ■ Composed of fibrous activated carbon and a binder, 0.4 g /
c A shaped adsorbent having a bulk density of c or more.

■100 parts of fibrous activated carbon and 2 to 40 parts of at least one of infusible thermofusible fiber, infusible carbon fiber, and thermosetting fiber
After molding the mixture consisting of 30 parts, the resulting molded body was
500-1500 under pressure of ~1000kg/cJ-G
A method for producing a shaped adsorbent characterized by heating at °C.

The fibrous activated carbon used in the present invention may be derived from any raw material such as coal pitch, petroleum pitch, phenol resin, PAN, and cellulose. Fibrous activated carbon usually has a fiber diameter of about 2 to 30 μm,
It is preferable that the fiber length is about 0.1 to 5 degrees, the pore radius is about 8 to 20 degrees, and the specific surface area is about 500 to 250 Or+f/g.

As the binding material, at least one of an infusible thermofusible resin, an infusible carbon fiber (more specifically, an unfired carbon fiber spun from raw material pitch and infusible treated), and a thermosetting resin are used. use.

Specific examples of the infusible thermofusible resin include infusible acrylic fibers (for example, commercially available under the trademark "Raftan", manufactured by Asahi Kasei Kogyo Co., Ltd.), infusible polyvinyl alcohol fibers, and the like. The term "infusible carbon fiber" refers to unfired carbon fiber obtained by spinning raw material pitch and subjecting it to infusibility treatment. Specific examples of the thermosetting resin include aramid fibers and phenol resins. The shape of these resins or fibers used as a binder is not particularly limited, but it is more preferable to use filamentous ones because they are less likely to block the pores of the fibrous activated carbon. As thread-like resin or fiber, the thread diameter is 5 to 100 μm.
It is preferable to use one with a length of about 0.1 to 5 mm.

The blending ratio of fibrous activated carbon and binder is usually 100% of the former.
2 to 40 parts of the latter, more preferably 10 parts of the former.
The latter is about 5 to 10 parts compared to 0 parts. Fibrous activated carbon 1
If the blending amount of the binder is less than 2 parts per 00 parts,
While the strength of the shaped adsorbent becomes insufficient, if the amount exceeds 40 parts, the pores of the fibrous activated carbon are blocked and the performance as an adsorbent deteriorates.

The blend of fibrous activated carbon and binder may optionally include:
Up to about 80 parts of reinforcing material may be further added to 100 parts of fibrous activated carbon. As such reinforcement material,
Examples include natural fibers such as hemp and paper pulp, and heat-meltable fibers such as polyethylene thread and polypropylene thread.

The method of the present invention is usually carried out as follows.

First, a compound consisting of fibrous activated carbon and a binder is molded. The molding method is not particularly limited, but a preferable example is
Examples include methods similar to papermaking methods. In this case, fibrous activated carbon, a binder, and if necessary a reinforcing material are dispersed in water at a predetermined ratio, beaten to prepare a uniform aqueous slurry, and then placed in a mold with a suction port at the bottom. Add slurry and suction from the bottom to obtain a molded material.

Next, after drying the obtained molded material, 30 to 1000
kg/c♂・G (more preferably 50-200
500 to 1500 under pressure (approximately kg/c♂・G)
Heating is carried out at a temperature of about 0.degree. C. (more preferably about 900 to 1500.degree. C.). When the pressurizing pressure is less than 30 kg/cm2・G, it is difficult to obtain a product with high bulk density;
If it exceeds 000 kg/crB-G, there is a possibility that the pores of the fibrous activated carbon will be destroyed. If the heating temperature is less than 500°C, it is difficult to obtain a product with sufficiently high bulk density, whereas if it exceeds 1500°C, the pores of the fibrous activated carbon may be blocked by the binder. be. This heating under pressure is also preferably carried out with the molded material housed in a mold in order to prevent deformation of the molded material.The heating treatment time under pressure depends on the type and properties of each material used, It may be selected as appropriate depending on the blending ratio of the adsorption molding material, the pressure and heating conditions, the dimensions of the molding material, and the performance required of the adsorption molding material depending on the application, but it is usually within the range of about 30 to 60 minutes. It is in.

Due to its high bulk density and high specific surface area properties, the adsorption molding material according to the invention is particularly useful as, for example, electrodes in electric double layer capacitors, cartridges for water purifiers, and the like.

Effect of the invention According to the present invention, the following remarkable effects are achieved.

(1) The bulk density of the obtained adsorption molding material is 0.4 g/cc
This is extremely high.

(2) Furthermore, the specific surface area of the adsorption molding material also exhibits a high value almost close to that of the fibrous activated carbon used.

EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention.

Example 1 250 parts of pitch-based fibrous activated carbon (trademark "A-10" manufactured by Adole Co., Ltd.) with a specific surface area of 1000 rri'/g and infusible acrylic fiber yarn (trademark "Raftan", manufactured by Asahi Kasei Industries, Ltd.) as a binder. ) was dispersed in 25 times the total weight of water, and each fiber length was 0.
．． The mixture was beaten to a thickness of 1 to 5 mm to obtain a uniform aqueous slurry.

Next, the above aqueous slurry was sucked using a mold having a number of suction ports at the bottom, and the upper part was pressed with a flat plate to flatten it, and then the molded body was taken out and heated at 140 ° C. for 120 minutes. Dry for a while.

The dimensions of the obtained dry molded body are 80 mm x 80 mm x 8
111 m, and its bulk density was 0.1 g/cc.

Next, the above dry molded body was 80 mm x 80 mm x 50 m.
50 kg/cJ-
The temperature was raised to 900°C at a rate of 30°C/min under pressure of G and held at the same temperature for 30 minutes to obtain a shaped adsorbent.

The dimensions of the molded adsorbent thus obtained are 80mm x 80mm.
The size was mm×1.5 mm, and the bulk density was 0.6 g/cc.

Example 2 Infusible carbon fiber (trademark “Donna Carbo S”) as a binder
A molded adsorbent was obtained in the same manner as in Example 1 except that a molded adsorbent (manufactured by DONAKU Co., Ltd.) was used.

The dimensions of the obtained molded adsorbent are 80 mm x 80 m x 1
．． At 5 mm, the bulk density was 0.6 g/cc.

Example 3 Thermosetting resin fiber yarn (trademark "Toweron",
A shaped adsorbent was obtained in the same manner as in Example 1 except that a molded adsorbent (manufactured by Nippon Aramid Co., Ltd.) was used.

The dimensions of the obtained molded adsorbent are 80mm x 80mm x 1
．． At 5 mm, the bulk density was 0.6 g/cc.

Example 4 A shaped adsorbent was obtained in the same manner as in Example 1, except that pitch-based fibrous activated carbon (trademark "A-20" manufactured by Adole Co., Ltd.) with a specific surface area of 2000 rrr/g was used as the fibrous activated carbon.

The dimensions of the obtained molded adsorbent are 80 mm x 80 + 5 m x
At 1.5 mm, the bulk density was 0.4 g/cc.

Example 5 Specific surface area 1500rr as fibrous activated carbon? A shaped adsorbent was obtained in the same manner as in Example 1, except that cellulose-based fibrous activated carbon (trademark "KF1500", manufactured by Toyobo Co., Ltd.) with a weight of 1.2 g was used.

The dimensions of the obtained molded adsorbent are 80mm x 80mm x 1
．． At 5u+, the bulk density was 0.55 g/cc.

Comparative Example 1 A molded adsorbent was produced in the same manner as in Example 1 except that no binder was used. However, the molded material after being pressurized and heated collapsed immediately upon being taken out from the crucible.

Test Example 1 A shaped adsorbent was obtained in the same manner as in Example 1 except that the pressure during pressurization and heating was varied.

FIG. 1 shows a graph showing the relationship between pressurizing pressure and bulk density of a molded product.

From the results shown in FIG. 1, the following points are clear.

If the pressing pressure during heating is less than 30 kg/cd·0, only a molded material having a bulk density of less than 0.4 g/CC can be obtained.

Pressure pressure is 30kg/cJ ・200kg/cJ from G
- The bulk density increases linearly with increasing up to G.

However, when the applied pressure exceeds 200 kg/cm2·G, no increase in bulk density is observed.

Test Example 2 A shaped adsorbent was obtained in the same manner as in Example 1, except that the heating temperature during pressurization and heating was varied.

FIG. 2 shows a graph showing the relationship between heating temperature and bulk density of the molded product.

From the results shown in Figure 2, if the heating temperature is too low,
It is clear that only products with low bulk densities are obtained.

It has been found that when the heating temperature exceeds 1500°C, the pores of the fibrous activated carbon are blocked by the adhesive component (tar component) from the binder, resulting in a significant decrease in the specific surface area of the molded product. It was done.

Test Example 3 Dry molded material obtained in the same manner as Example 1 (weight 20 m g
) was heated to 900°C at a rate of 30°C/min, and the weight change of the molded material was investigated.

FIG. 3 shows a graph showing the relationship between the heating temperature and the weight of the molded product.

From this graph, it can be seen that it is around 600°C that gas components noticeably flow out from the raw material and the weight decreases, so the decomposition of the tar component progresses around this temperature, and due to the tar component that flows out and decomposes, It is presumed that the fibrous activated carbon is bonded.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the pressurizing pressure during production of a molded product and the bulk density of the molded product. FIG. 2 is a graph showing the relationship between the heating temperature during molded product production and the bulk density of the molded product. FIG. 3 is a graph showing the relationship between the heating temperature during molded product production and the weight of the molded product. (That's all) Diagram: (kll!, /Cm2) Diagram: Quenching temperature (°C)

Claims (2)

[Claims] (1) Composed of fibrous activated carbon and binding material, 0.4g
A shaped adsorbent having a bulk density of /cc or more. (2) 100 parts of fibrous activated carbon and at least 2 or more of infusible thermofusible fibers, infusible carbon fibers, and thermosetting fibers;
After molding a compound consisting of 40 parts, the resulting molded body was heated at 500 to 1000 kg/cm^2・G under a pressure of 30 to 1000 kg/cm^2・G.
A method for producing a shaped adsorbent, the method comprising heating at 1500°C.