JPH0761875A - Production of molded hollow active carbon - Google Patents

Abstract

PURPOSE:To improve heat resistance, chemical resistance and lightness by embedding a granular thermoplastic resin in active carbon powder, melting and carbonizing at a specific temperature while vibrating. CONSTITUTION:A granular thermoplastic resin is embedded in active carbon powder, heat-treated at 250-350 deg.C in an oxidizing atmosphere and infusibilized. Then the infusibilized material is heat-treated in a temperature range from about the melting point of the granular thermoplastic resin to the melting point +10 deg.C while intermittently vibrating the infusibilized material.

Description

Detailed Description of the Invention

[0001]

[Field of Industrial Application] Among the hollow carbon body moldings that are currently expected to be used as a material having excellent properties such as heat resistance, chemical resistance, and light weight, the present invention is The present invention relates to a method for producing an activated carbon, that is, a hollow activated carbon molded product.

[0002]

2. Description of the Related Art As a method for producing a hollow carbon body molded article, a bituminous material such as a thermoplastic organic polymer material or petroleum pitch is uniformly mixed with an expander such as a low boiling point solvent, and then an appropriate particle size is obtained. To obtain a hollow carbon body by heating and carbonizing it (for example, Japanese Patent Publication No. 49-3025).
No. 3, Japanese Patent Publication No. 61-14110, Japanese Patent Laid-Open No. 61
No. 83,239) or a core material such as a thermoplastic resin is coated with a substance having a high melting point to form spheres having a multi-layered structure, and then the spheres are heated and carbonized (for example, Japanese Patent Publication No. 50-29837).
(See Japanese Patent Publication) and the like are known.

[0003]

In these production methods, the method of using a swelling agent includes selection of a swelling agent suitable for each raw material, handling of organic solvents, adjustment of particles containing a swelling agent, and Has a drawback in that it is difficult to set conditions and handle during heat treatment, and the method involving a multilayer structure has a drawback that only a molded product having a relatively large particle size can be obtained. In addition, in any of these methods, in order to obtain a product in which the carbon body is activated carbon, that is, a hollow activated carbon molded product, it is necessary to add a technique to achieve the activated carbon function. .

Therefore, the present inventor has previously proposed one method for producing hollow activated carbon moldings having various particle diameters by a very simple process (Japanese Patent Application No. 4-1).
No. 02097). Using a particulate thermoplastic resin and activated carbon powder, embedding the particulate thermoplastic resin in the activated carbon powder, and then subjecting this particulate thermoplastic resin to heat treatment to melt and carbonize, produce a hollow activated carbon molded product Is to do. Here, a hollow molded article is not a mere aggregated particle of activated carbon powder, but activated carbon powder does not enter the molten particulate thermoplastic resin,
It is presumed that this is because the molten particulate thermoplastic resin penetrates into the interstices between the activated carbon powders (aggregates).

The present invention further develops the above-mentioned proposal, and makes the molten particulate thermoplastic resin more uniformly adhere the activated carbon powder particles, and further enhances the function of the obtained hollow activated carbon molded article. Is.

[0006]

According to the present invention, a hollow activated carbon molded article is produced by embedding a particulate thermoplastic resin in activated carbon powder and then subjecting the particulate thermoplastic resin to heat treatment for melting and carbonizing. In doing so, in the heat treatment, in the melting temperature range of the particulate thermoplastic resin, the production of a hollow activated carbon molded article characterized by being performed by vibrating the particulate thermoplastic resin or activated carbon powder to shake. The method is the gist.

The details will be described below. As the particulate thermoplastic resin used in the present invention, for example, polyethylene, polypropylene, polystyrene, nylon, polyvinyl chloride,
Various materials such as polyvinyl acetate and mixtures thereof can be used. When trying to obtain a hollow activated carbon molded product having a relatively small diameter, the carbon yield by heat treatment is also made relatively small,
When a hollow activated carbon molded product having a relatively large diameter is to be obtained, it is preferable that the carbon yield by the heat treatment is also relatively large. That is, the particle size of the particulate thermoplastic resin is preferably 5 times or more as large as the particle size of the activated carbon powder, but the activated carbon powder itself can be selected to be very small, so that a sufficiently small one can be selected and obtained. Hollow activated carbon moldings can also be very small. However, at this time, it is preferable that the carbon yield is not so high in order to secure the hollow portion as hollow as possible. Moreover, a large hollow activated carbon molded product can be obtained by using a large particulate thermoplastic resin. However, at this time, if the carbon yield is too small, it becomes difficult to stabilize the shape of the obtained hollow activated carbon molded product. The carbon yield is generally 1
It is good to set it to about 10%. For example, polyethylene, polypropylene, polystyrene, nylon, etc. are subjected to infusibilizing treatment in an oxidizing atmosphere and then carbonization treatment in a non-oxidizing atmosphere, and polyvinyl chloride, polyvinyl acetate, etc. are treated in an oxidizing atmosphere. By performing the heat treatment in the non-oxidizing atmosphere without performing the fusion treatment, the carbon yield can be easily set to about 1 to 10%. In addition, polyethylene is available as commercially available spherical or granular products having various particle diameters of several μm to more than 1000 μm, and it is easy to set the size of the hollow activated carbon molded product to be obtained.

As the activated carbon powder, regardless of the raw materials and the manufacturing method, etc., the properties and the particle size may be appropriately selected in consideration of the intended use of the hollow activated carbon molded product to be obtained and the particle size of the particulate thermoplastic resin. Good. It is also suitable in terms of the shape such as a completely amorphous shape or a fibrous shape. Chemically activated carbon may have a higher content of impurities than gas-activated carbon, and if this amount of impurities is too high, it may hinder the formation of hollow activated carbon moldings. It is also possible to remove impurities by washing with the above inorganic acid. Further, the particulate thermoplastic resin is embedded in the activated carbon powder, but it is sufficient that the activated carbon powder exists in a thickness equal to or greater than the wall thickness of the hollow activated carbon molded product to be obtained around the particulate thermoplastic resin. . Furthermore, other materials such as gold, silver, copper, titanium oxide, zinc oxide, and zeolite can be appropriately used together with the activated carbon or together with the particulate thermoplastic resin.

The heat treatment may be appropriately performed depending on the kind of the particulate thermoplastic resin as described above. For example, air,
After infusibilizing by heating from room temperature to 250 to 350 ° C. in an oxidizing atmosphere such as oxygen, the particulate thermoplastic resin is treated in a non-oxidizing atmosphere such as in an inert gas such as nitrogen or argon or in a vacuum. The treatment is performed up to the carbonization temperature, or the treatment is performed directly in the non-oxidizing atmosphere without performing the infusibilizing treatment in the oxidizing atmosphere.

However, in this heat treatment, in the melting temperature range of the particulate thermoplastic resin, vibration is applied so as to shake the particulate thermoplastic resin and the activated carbon powder. For example, from around the melting point of the particulate thermoplastic resin to exceeding the melting point of several tens of degrees Celsius
Temperature range, for example, from a very low temperature to a high temperature above the melting point, in brief, the activated carbon powder in which the particulate thermoplastic resin is embedded is housed in a container, and the container, vibrator type or mallet is used. The heat treatment is performed while continuously or intermittently vibrating by an appropriate vibration adding means such as a hitting method. Of course, it is not necessary to apply too much vibration. Shake,
That is, the contact surface between the particulate thermoplastic resin and the activated carbon powder particles is changed, rather, the dispersion state of the particulate thermoplastic resin embedded in the activated carbon powder is changed so that the particulate thermoplastic resin is mutually Avoid being integrated into.

By applying the vibration in this way, the activated carbon powder particles can be more uniformly adhered to the molten particulate thermoplastic resin as compared with the case where the vibration is not applied. The present inventors presume the reason for this as follows.

As described above, although the mechanism by which the hollow activated carbon molded product is formed is not always clear, the particulate thermoplastic resin embedded in the activated carbon powder is once melted by heat treatment and becomes fluid, This penetrates into the interstices between the activated carbon powders (aggregates), in other words, the activated carbon powder particles are stuck one after another, and then the particulate thermoplastic resin remains as a carbide to serve as a binder, and the hollow activated carbon It is considered that a molded product is formed. At this time, in the melting temperature region of the particulate thermoplastic resin, when heat treatment is performed by adding vibration to shake the particulate thermoplastic resin or activated carbon powder, activated carbon powder particles are formed on the surface of the molten particulate thermoplastic resin. The gaps between the particulate thermoplastic resin and the activated carbon powder particles produced by sticking are successively filled with the adjacent activated carbon powder particles. As a result, the activated carbon powder particles are more uniformly and evenly adhered to the surface of the melted particulate thermoplastic resin. In addition, if the particulate thermoplastic resin does not remain inside, the hollowness of the hollow portion will be high, such as utilizing all of the molten particulate thermoplastic resin for sticking the activated carbon powder particles. If a part of the resin remains inside without being used for sticking the activated carbon powder, the hollow part becomes relatively hollow, such as a mesh space.

It is sufficient that the maximum temperature of the heat treatment is about several hundred degrees Celsius. Further, the particulate thermoplastic resin may be partially carbonized. In addition, activation treatment may be performed as necessary. The hollow activated carbon molded product obtained by removing excess activated carbon powder by sieving after the heat treatment as described above may have an excellent activated carbon function as it is and may be easy to handle. However, by further filling the hollow portion with another substance or immobilizing microorganisms or the like, the performance can be improved or another function can be added. For example, if pesticides and insecticides are filled, they are once adsorbed by activated carbon on the outside and then gradually released, so that they can be sustained-release pesticides and sustained-release insecticides that can maintain their long-term effects. If a volatile substance such as an aromatic is filled, the volatility can be maintained for a long period of time. Further, for example, by providing a hole of about several μm that allows microorganisms to easily enter into the hollow portion in the outer shell portion made of the carbide of the molten particulate thermoplastic resin and the activated carbon powder, the hollow portion serves as a growth space for the microorganism. It is also possible to use it, that is, to use it as a microorganism culture substrate. Moreover, if a microorganism to be immobilized is selected in consideration of the combination with activated carbon, it can be used as a microorganism-supporting activated carbon having both functions of physicochemical treatment and biological treatment of wastewater and the like. The filling of the substance into the hollow portion and the immobilization of the microorganisms may be performed by immersing the hollow activated carbon molded product in a solution containing the filling substance or a culture solution containing the microorganisms.

[0014]

【Example】

<Example 1> Flow beads CL-12007 (spherical low-density polyethylene manufactured by Sumitomo Seika Chemicals Ltd .: particle size range: 60)
0-1200 μm, melting point; 107 ° C.)
100 (powdered activated carbon manufactured by Mitsubishi Kasei Co., Ltd .: particle size; 1
It is buried in the air (00 mesh or less) and the temperature is from room temperature to 30
Raise the temperature to 0 ° C at a rate of 2 ° C / min, and increase to 1 at 300 ° C.
An infusibilizing treatment for holding the time was performed. Here, 105 ℃ ~
Up to 150 [deg.] C., a container containing a flow bead and a diazobe was subjected to heat treatment while being continuously vibrated by a vibrator (50 Hz). Then, in a nitrogen atmosphere, 60
The treatment was performed at 0 ° C. for 1 hour, and after the heat treatment was completed, excess activated carbon powder was removed by sieving to obtain a true spherical hollow activated carbon molded product.

<Example 2> In Example 1, the flow beads CL-12007 used were flow beads HE-5.
023 (a true spherical high-density polyethylene manufactured by Sumitomo Seika Chemicals Ltd .: particle size range: 6 to 50 μm, melting point: 132 ° C.), and a temperature range to which vibration is applied is 130 to 180 ° C.
A spherical hollow activated carbon molded product was obtained in the same manner as in Example 1 except that the above was changed to.

<Example 3> The flow beads CL-12007 used in Example 1 were replaced with Toray AQ-Nylon P.
-70 (a rectangular parallelepiped water-soluble nylon pellet manufactured by Toray Industries, Inc .: length, width: about 4 mm, height: about 3 mm, melting point: 118
C.), the temperature rising rate was changed to about 1 ° C./min, and the method of applying vibration was changed to repeat vibration and vibration stop every 1 minute from 115 ° C. to 160 ° C. In the same manner as in Example 1, a substantially rectangular parallelepiped hollow activated carbon molded product was obtained.

Example 4 Cylindrical polyvinyl chloride resin pellets (diameter: about 3 mm, height: about 4) for molding the flow beads CL-12007 used in Example 1
mm, melting point; 255 ° C.) and heat treatment in a nitrogen atmosphere from room temperature to 300 ° C. at a rate of about 1 ° C./min, and from 300 to 600 ° C. at a rate of about 2 ° C./min. Change the temperature to 600 ° C and hold for 1 hour.
Cylindrical hollow activated carbon moldings were obtained in the same manner as in Example 1 except that the method of applying vibration was changed from 250 ° C. to 300 ° C. such that vibration and vibration stop were repeated every 1 minute.

<Example 5> In Example 1, except that the used diasorb F100 was replaced with Kuraray Coal PK30 (powdered activated carbon manufactured by Kuraray Chemical Co., Ltd .: particle size; 30 mesh or less). In the same manner as in No. 1, a spherical hollow activated carbon molded product was obtained.

In each of the above examples, the one obtained without applying vibration during the heat treatment was the same as the one obtained in each of the above examples in terms of the shape of the true sphere, but when observed by breaking, The one obtained in the example has a thicker outer shell,
The activated carbon function was also effectively exhibited.

[0020]

EFFECTS OF THE INVENTION According to the present invention, hollow activated carbon moldings of various particle diameters and shapes capable of effectively adhering a large number of activated carbon powder particles uniformly and exhibiting the activated carbon function require complicated manufacturing steps. Can be easily obtained without.

Claims (1)

[Claims] 1. A method for producing a hollow activated carbon molded article by embedding a particulate thermoplastic resin in activated carbon powder, and then subjecting the particulate thermoplastic resin to heat treatment for melting and carbonizing A method for producing a hollow activated carbon molded article, which comprises performing vibration so as to shake the particulate thermoplastic resin or activated carbon powder in a melting temperature range of the particulate thermoplastic resin.