JPH08295506A - Hollow activated carbon-titanium dioxide composite and its production - Google Patents

Abstract

PURPOSE: To obtain a hollow activated carbon-titanium dioxide composite having the adsorptivity for harmful materials particular to activated carbon and the decomposability for harmful materials particular to titanium dioxide by mixing an melting a granular thermoplastic resin with a powdery activated carbon to produce a molding, sticking powdery titanium oxide alone or a composite or mixture with other materials directly or indirectly to the surface of the molding, and after that, carbonizing by heating to make the activated carbon molding hollow and to directly or indirectly fix the powdery titanium dioxide. CONSTITUTION: The powdery activated carbon >=3 times more than the particulate thermoplastic resin in volume ratio is preferably used. Gold, silver, titanium dioxide, zinc oxide, zeolite or the like can be properly used jointly with activated carbon. The granular thermoplastic resin such as polyethylene, polypropylene is used. As the titanium dioxide, the anatase type and rutile type can bee used and the particle diameter is controlled to 0.1-1.0μm. The heating condition for obtaining the molding is 250-350 deg.C. The size of the molding is preferably 100μm to 5mm.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an environmental pollutant or the like by irradiating light onto at least the outer surface of a hollow activated carbon molded article which is currently expected to be used as a material having excellent properties such as adsorptivity and light weight. The present invention relates to a hollow activated carbon / titanium dioxide composite to which titanium dioxide powder, which has been attracting attention in recent years because of its ability to decompose and render harmless, and a method for producing the same.

[0002]

2. Description of the Related Art Hollow carbon molded articles are manufactured by uniformly mixing a thermoplastic organic polymer material, a bituminous material such as petroleum pitch with a swelling agent such as a low boiling point solvent, and then preparing an appropriate particle size. A method of forming powders and then carbonizing by heating (for example, JP-B-49-30253, JP-B-61-14110, JP-A-61-83239), or a core material such as a thermoplastic resin having a high boiling point A sphere having a multi-layered structure by coating with the above substance, followed by heating and carbonization (for example, Japanese Patent Publication No. 50-2
No. 9837) is known.

[0003]

SUMMARY OF THE INVENTION In these methods,
In the method of using the expander, selection of expander suitable for each raw material, handling of organic solvents, adjusting method of expander-containing particles, further, there are many difficult points such as condition setting and handling during heat treatment, In addition, the method using a multilayer structure has a drawback that only hollow bodies 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 for merely exhibiting the activated carbon function. One of them is to have sufficient communicating holes from the hollow portion to the outside.

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 Laid-Open No. 5-30).
1784). 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. According to this production method, it is possible to easily obtain a hollow activated carbon molded product having a sufficient activated carbon function such as having a sufficient number of ventilation holes from the hollow portion to the outside. Here, the hollow molded article is not a mere aggregated particle of activated carbon powder, but the activated carbon powder does not enter the molten particulate thermoplastic resin, but the molten particulate thermoplastic resin is activated carbon. It is presumed that this is because the powder (aggregate) permeates into the gaps between the powders (aggregates).

On the other hand, titanium dioxide has been particularly attracting attention in recent years because it generates active oxygen when irradiated with light, and the active oxygen decomposes and detoxifies environmental pollutants.
Applications in a wide range of fields such as water treatment, air treatment, and soil treatment are expected. According to the present invention, by fixing this titanium dioxide powder to at least the outer surface of the above-mentioned hollow activated carbon molded article, a hollow activated carbon / dioxide that shares the ability of the activated carbon to adsorb harmful substances and the ability of titanium dioxide to decompose harmful substances. It is intended to provide a titanium composite and a method for producing the same.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to titanium dioxide powder alone or titanium dioxide powder and other substances on at least the outer surface of a hollow activated carbon molded article composed of activated carbon powder and a carbonized material of a particulate thermoplastic resin. The first gist is a hollow activated carbon / titanium dioxide composite in which the particulate thermoplastic resin and the activated carbon powder are used, and the particulate thermoplastic resin and the activated carbon powder are mixed, A hollow activated carbon molded product is produced by melting and carbonizing a plastic resin, and further, at least the outer surface of the hollow activated carbon molded product contains titanium dioxide powder alone or a composite of titanium dioxide powder and another substance. Alternatively, a mixture of titanium dioxide powder and another substance may be directly or indirectly attached and then heat treated to fix the titanium dioxide powder directly or indirectly. The second aspect is a method for producing a hollow activated carbon / titanium dioxide composite, wherein a particulate thermoplastic resin and an activated carbon powder are used, and the particulate thermoplastic resin and the activated carbon powder are mixed, An activated carbon molded product is produced by melting a thermoplastic resin, and at least the outer surface of the activated carbon molded product contains titanium dioxide powder alone, or a composite of titanium dioxide powder and another substance, or dioxide. It is characterized in that a mixture of titanium powder and another substance is directly or indirectly adhered, and then a carbonization heat treatment is applied to make the activated carbon molded product hollow, and the titanium dioxide powder is directly or indirectly fixed. Third method for producing hollow activated carbon / titanium dioxide composites
The summary of the

The present invention will be described in detail below. The properties and size of the activated carbon powder used in the present invention may be appropriately selected in consideration of the application of the hollow activated carbon / titanium dioxide composite, regardless of the raw materials and the manufacturing method. Further, it is also appropriate in terms of a shape such as a completely amorphous shape or a fibrous shape. The larger the specific surface area of the activated carbon powder used, the larger the specific surface area of the hollow activated carbon molded product obtained. Incidentally, the chemical activated carbon may have a large amount of impurities as compared with the gas activated carbon, and if this amount of impurities is too large, it may hinder the formation of a hollow activated carbon molded product.
If necessary, the activated carbon may be washed in advance with an inorganic acid such as hydrochloric acid to remove impurities. In addition, the particulate thermoplastic resin and the activated carbon are so arranged that the activated carbon powder exists in a thickness equal to or greater than the wall thickness of the hollow activated carbon molded article to be obtained around the particulate thermoplastic resin or the activated carbon forming the activated carbon molded article. The powder and the powder are dispersed and mixed. At this time, it is preferable to use at least three times the volume of the particulate thermoplastic resin as the activated carbon powder. Furthermore, with activated carbon, gold,
Other materials such as silver, copper, titanium dioxide, zinc oxide, and zeolite can also be appropriately used in combination.

Examples of the particulate thermoplastic resin include various materials such as polyethylene, polypropylene, polystyrene, nylon, polyvinyl chloride, polyvinyl acetate, and mixtures thereof. When trying to obtain a relatively small hollow activated carbon / titanium dioxide complex, the carbon yield from the heat treatment is also relatively small, and when trying to obtain a relatively large hollow activated carbon / titanium dioxide complex, the carbon yield from the heat treatment. Is also preferably relatively large. That is, the size of the particulate thermoplastic resin is preferably 5 times or more the particle size of the activated carbon powder, but the activated carbon powder itself can be selected to be very small, so the particulate thermoplastic resin is also sufficiently small. The hollow activated carbon / titanium dioxide composite obtained can 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. Also, a large hollow activated carbon / titanium dioxide composite can be obtained by using a large particulate thermoplastic resin. However, at this time, if the carbon yield is too low, it becomes difficult to stabilize the shape of the obtained hollow activated carbon / titanium dioxide composite. In general, the carbon yield is preferably about 1-10%. For example,
For polyethylene, polypropylene, polystyrene, nylon, etc., by infusibilizing treatment in an oxidizing atmosphere and then carbonizing treatment in a non-oxidizing atmosphere,
For polyvinyl chloride, polyvinyl acetate, etc., the carbon yield can be easily reduced to 1 to 3 by performing heat treatment in a non-oxidizing atmosphere without performing infusibilizing treatment in an oxidizing atmosphere.
It can be about 10%. Also, polyethylene is several μm to 1
True spherical and granular materials with various particle sizes exceeding 000 μm
Alternatively, various pellets of about several mm are available as commercial products, and it is easy to set the size of the hollow activated carbon / titanium dioxide composite to be obtained.

As the titanium dioxide, either anatase type or rutile type crystal form can be used, and further, ultrafine particle form or amorphous form which has been developed in recent years, or hydrophobic form. Various types such as those having a surface state can be selected according to the situation of use. In general, the particle size of titanium dioxide is about 0.1 to 1.0 μm, but the particle size of ultrafine particles is about 2 to 50 nm, and the photoactivity is higher than that of general one. In addition, titanium dioxide / PMMA composite fine particles, which are aggregates of titanium dioxide surface-treated with PMMA (commercial products include "Techpolymer-MBTP" and "Techpolymer-MBT" manufactured by Sekisui Plastics Co., Ltd.) It is particularly preferable because the strength of fixation of the hollow activated carbon molded product or the activated carbon molded product to the outer surface is improved.

The heat treatment until the hollow activated carbon molded product is obtained may be appropriately performed depending on the kind of the particulate thermoplastic resin as described above. For example, the temperature is raised from room temperature to 250 to 350 ° C. in an oxidizing atmosphere such as air or oxygen, and the activated carbon powder is fixed to the outer surface of the particulate thermoplastic resin, and after infusibilizing treatment, nitrogen, argon, etc. In a non-oxidizing atmosphere such as in an inert gas or in vacuum, heat treatment is performed to the temperature at which the particulate thermoplastic resin is carbonized, or without performing heat treatment in an oxidizing atmosphere Heat treatment is performed to a temperature at which the thermoplastic resin is carbonized.
In order to obtain an activated carbon molded product, 2
The heat treatment may be performed at 50 to 350 ° C., and after the heat treatment, excess activated carbon powder is removed by sieving. Depending on the processing temperature and processing time conditions, a hollow activated carbon molded product may already be formed at this stage. Among these heat treatments, it is preferable to perform the heat treatment while rotating the particulate thermoplastic resin and the activated carbon powder in the melting temperature range of the particulate thermoplastic resin.
Simply, it is sufficient that the container itself containing the material can rotate and be heated. For example, activated carbon powder mixed with a particulate thermoplastic resin is placed in a rotary kiln such as a rotary kiln and heat-treated while rotating. The number of revolutions of the rotary furnace, the treatment temperature, the treatment time, etc. are appropriately set, but first, if the number of revolutions is too small, the material only moves in parallel in the rotary furnace, so at least 1 revolution / minute or more is preferable, and vice versa. If it is too large, the activated carbon powder particles that adhere may come off, so 1
It is better to keep it below 0 rpm. The treatment temperature is in the melting temperature range of the particulate thermoplastic resin, but if the wall thickness of the activated carbon is to be increased, a melting temperature range as high as possible within the range below the decomposition temperature of the particulate thermoplastic resin is adopted. Is good. For example, if polyethylene is used as the particulate thermoplastic resin, the temperature is preferably about 250 to 350 ° C. The treatment time is preferably set in relation to the treatment temperature and may be short when the treatment temperature is high, but needs to be long when the treatment temperature is relatively low. If the particulate thermoplastic resin is sufficiently infusibilized by contact with air in the rotary furnace, then it can be immediately carbonized in a non-oxidizing atmosphere. If the contact with air is insufficient and the infusibilization process is incomplete,
It is necessary to perform the infusibilizing treatment in an oxidizing atmosphere again before performing the carbonization treatment. At this time, the material does not need to be rotated and may remain stationary. After the infusibilizing treatment, a carbonizing treatment in a non-oxidizing atmosphere is performed, but a maximum temperature of about several hundred degrees Celsius is sufficient. Moreover, you may give an activation process as needed. After the heat treatment, the excess activated carbon powder is removed with a sieve or the like to obtain a hollow activated carbon molded product. The size of the hollow activated carbon molded product can be freely obtained in the range of several μm to several mm, but if it is too small, there is no difference from the powdered activated carbon, and conversely, if it is too large, the effective area per unit weight becomes small. 100, because the practical strength is insufficient.
It is preferable to suppress the thickness to about 5 μm to 5 mm. However, if the strength is not so required, it may be increased. Since the hollow portion of the hollow activated carbon molded article communicates with the outside world, gas and the like enter this hollow portion, and the activated carbon in a wide range of inside and outside exerts its function. Furthermore, although it is lightweight, it is not in powder form, so handling is very good.

Next, as a method for fixing the titanium dioxide powder to at least the outer surface of the obtained hollow activated carbon molded product or activated carbon molded product (hereinafter referred to as "base material"),
After the titanium dioxide powder is sprinkled on the outer surface of the base material or the base material is agitated in the titanium dioxide powder, the base material and titanium dioxide are sufficiently contacted and adhered to each other, and then heat treatment is applied to the outside of the base material. A simple method is to fix the titanium dioxide powder on the surface. When a solid activated carbon molded product is used as the base material, the residual portion of the particulate thermoplastic resin is transferred to the outer surface of the activated carbon molded product by the carbonization heat treatment, whereby the titanium dioxide powder is firmly fixed. On the other hand, when the hollow activated carbon molded product is used as the base material, the carbonization of the particulate thermoplastic resin has already been completed, so that the titanium dioxide powder is not firmly fixed. Therefore, it is preferable to use a mixture of titanium dioxide powder with a small amount of a binder as needed, or to coat a solution of a binder on the outer surface of the base material. Examples of the binder include a thermoplastic resin and a colloidal aqueous solution of silicic acid anhydride. Among the thermoplastic resins, polyvinylidene chloride resin is preferable because it is activated carbonized without activation treatment when heated in an inert atmosphere or in a vacuum. Further, if the ultrafine particles of silicic acid anhydride are interposed between the base material and the titanium dioxide powder, a porous structure is formed after the surface fusion between the silica particles by the high temperature heat treatment, whereby the titanium dioxide powder on the base material is dispersed. Increases the bond strength and secures the activated carbon function. Furthermore, as described above, when titanium dioxide / PMMA composite fine particles are used, PMMA melted by heat treatment plays a role of an adhesive, and the adhesion strength of titanium dioxide powder to the outer surface of the base material is improved without using a binder. Therefore, it is particularly preferable. However, in this case, titanium dioxide / PM should be used to prevent individual molded products from sticking to each other.
It is necessary to heat-treat the untreated titanium dioxide powder again on the surface of the base material to which the MA composite particles have been attached. The heat treatment temperature may be up to several hundred degrees Celsius,
When a solid activated carbon molded product is used as the base material, it is subjected to an infusibilizing treatment, if necessary, as in the case of obtaining the hollow activated carbon molded product, and then subjected to a carbonization treatment in a non-oxidizing atmosphere.
The infusibilizing treatment and the subsequent carbonization treatment may be performed with the base material embedded in the titanium dioxide powder, or only the carbonization treatment may be performed in that manner.

Hollow activated carbon obtained by the above treatment
The titanium dioxide composite is classified into the following six types depending on the form of titanium dioxide powder and its adhesion to the outer surface of the substrate, but the present invention is not limited thereto. (1) Titanium dioxide powder alone and directly adhered to the outer surface of the substrate. (Examples 1 and 4 described below) (2) A composite of titanium dioxide powder and another substance is directly adhered to the outer surface of the base material. (Examples 2, 3 and 5 described later) (3) A mixture of titanium dioxide powder and another substance is directly adhered to the outer surface of the base material. (Examples 6 and 11 described later) (4) Titanium dioxide powder was adhered to the outer surface of the base material independently through another substance. (Examples 7 and 8 described later) (5) A composite of titanium dioxide powder and another substance is fixed to the outer surface of the base material through another substance. (Example 9 described later) (6) A mixture of titanium dioxide powder and another substance is fixed to the outer surface of the base material through another substance. (Example 1 described later
0)

The hollow activated carbon / titanium dioxide composite thus obtained is used to decompose and detoxify environmental pollutants by irradiating light on the outer surface of a hollow activated carbon molded article having excellent properties such as adsorption and light weight. Titanium dioxide powder with the ability to make it adhere is fixed, and it shares the ability of activated carbon to adsorb harmful substances and the ability of titanium dioxide to decompose harmful substances.
Use in environmental fields such as water treatment, air treatment, soil treatment,
Alternatively, it can be expected to be effective in various applications such as removal of odors and dirt of pets and toilets in the home, removal of algae in the aquarium, etc.

[0014]

The present invention will be described below in detail with reference to examples. <Example 1> Flow beads CL-12007 (spherical polyethylene made by Sumitomo Seika Chemicals Ltd .: particle size range: 600 to 1)
200 μm, melting point; 107 ° C.) and 3 times the amount of Diasorb F100 (powdered activated carbon manufactured by Mitsubishi Kasei Co., Ltd .: particle size;
100 mesh or less), and mix it with a treatment temperature of 30
It was placed in a rotary kiln under the conditions of 0 ° C. and a rotation speed of 2 rotations / minute, and heat treatment was performed for 10 minutes. Next, the material taken out from the rotary kiln is transferred to a container and heated in air from room temperature to 250 ° C. at a rate of about 2 ° C./minute to 250 ° C.
The infusibilizing treatment of holding for 1 hour was performed. Then, carbonization treatment was carried out at 600 ° C. for 1 hour in a nitrogen atmosphere, and after the heat treatment was completed, excess activated carbon powder was removed by sieving to obtain a hollow activated carbon molded product. Next, this hollow activated carbon molded product was embedded in TITONO.R-7E (titanium dioxide powder manufactured by Sakai Chemical Industry Co., Ltd .: average particle size: 0.2 μm), and then 250 ° C. in air for 1 hour. Heat treatment to hold,
After the heat treatment was completed, excess TITONO.R-7E was removed by sieving to obtain a spherical hollow activated carbon / titanium dioxide composite having an outer diameter of 1200 to 2000 μm.

Example 2 On the outer surface of the hollow activated carbon molded article obtained in Example 1, techpolymer-MBTP (titanium dioxide / PMMA composite fine particles manufactured by Sekisui Plastics Co., Ltd .: average particle size: 5 μm) Was thoroughly sprinkled and adhered, then embedded in TITONO.R-7E and subjected to heat treatment, in the same manner as in Example 1 except that the adhesion strength of the titanium dioxide powder to the outer surface of the hollow activated carbon molded article was fixed. Was obtained, and a spherical hollow activated carbon / titanium dioxide composite having an outer diameter of 1200 to 2000 μm was obtained.

<Embodiment 3> Flow beads CL-5007
(True spherical polyethylene manufactured by Sumitomo Seika Chemicals, Ltd .: particle size range;
200-500 μm, melting point; 107 ° C.) and 3 times the amount of diasorb F100 were mixed, and then heat-treated in a rotary kiln under the same conditions as in Example 1, and after the heat treatment was completed, excess activated carbon powder was removed. It was removed by a sieve to obtain an activated carbon molded product.
Next, techpolymer-MBT was applied to the outer surface of the activated carbon molded product.
Thoroughly sprinkle P on it and attach it
-Embedded in R-7E, infusible treatment was carried out by holding in air at 250 ° C for 1 hour. Then, in a nitrogen atmosphere, 6
After the carbonization treatment of holding at 00 ° C for 1 hour, and after the heat treatment,
Excessive TITONO.R-7E was removed by sieving to obtain a spherical hollow activated carbon / titanium dioxide composite having an outer diameter of 400 to 900 μm and having a high fixing strength of titanium dioxide powder as in Example 2.

<Embodiment 4> Flow beads CL-5007
And a three-fold amount of Diasoab F100 were mixed, and the mixture was rotary-treated under the conditions of a processing temperature of 250 ° C. and a rotation speed of 2 rotations / minute.
After being placed in a kiln and subjected to a heat treatment for 20 minutes, after the heat treatment was completed, excess activated carbon powder was removed by sieving to obtain an activated carbon molded product. Next, this activated carbon molded product was treated with Titania IT-PC.
(Ultrafine particulate titanium dioxide powder manufactured by Idemitsu Petrochemical Co., Ltd .: average particle size; 60 nm), embedded in a nitrogen atmosphere at 600 ° C. for 1 hour for carbonization, and after the heat treatment, excess The titania IT-PC was removed by sieving to obtain a spherical hollow activated carbon / titanium dioxide composite having an outer diameter of 400 to 900 μm.

<Example 5> UBE: L519 (cylindrical polyethylene pellets manufactured by Ube Industries, Ltd .: diameter of about 3.
5 mm, height about 2 mm, melting point 104 ° C.) and 5 times amount of diasorb F100 are mixed and treated at a processing temperature of 300
It was placed in a rotary kiln under the conditions of a temperature of 3 ° C. and a rotational speed of 3 revolutions / minute, and heat treatment was performed for 15 minutes. Next, the material taken out from the rotary kiln was transferred to a container, and the temperature was raised from room temperature to 2
Increase the temperature to 50 ° C at a rate of 2 ° C / min to 250 ° C.
The infusibilizing treatment of holding for 1 hour was performed. Then, carbonization treatment was carried out at 600 ° C. for 1 hour in a nitrogen atmosphere, and after the heat treatment was completed, excess activated carbon powder was removed by sieving to obtain a hollow activated carbon molded product. Next, techpolymer-MBTP was thoroughly sprinkled and adhered to this hollow activated carbon molded product, which was then embedded in TITONO.R-7E and subjected to a heat treatment of 250 ° C. for 1 hour in air, After completion of the heat treatment, the excess TITONO.R-7E was removed by sieving, and as in Example 2, the titanium dioxide powder had a high fixing strength, and a hollow cylindrical activated carbon having a diameter of about 5 mm and a height of about 3 mm was formed into a substantially columnar shape. -A titanium dioxide composite was obtained.

Example 6 The hollow activated carbon molding obtained in Example 1 was dipped in methyl ethyl ketone to be sufficiently impregnated with methyl ethyl ketone, and then the polyvinylidene chloride resin powder (manufactured by Dow Chemical Co.) ) And TITON
Powdered by mixing O.R-7E with 1: 5 (weight ratio) was thoroughly sprinkled and adhered.
It is embedded in -7E, heat-treated at 700 ° C for 1 hour in a nitrogen atmosphere, and after the heat-treatment is completed, excess TITON
O.R-7E was removed by sieving to increase the adhesion strength of the titanium dioxide powder to the outer surface of the hollow activated carbon molded product and activated carbonization of the polyvinylidene chloride resin powder.
A 2000 μm spherical hollow activated carbon / titanium dioxide composite was obtained.

<Example 7> M-141 (Showa Denko KK)
Made polyethylene pellets: diameter about 2.5m
m, height about 3.5 mm) and 5 times the amount of diamond solvent F10
0 was mixed, and the mixture was placed in a rotary kiln under the conditions of a treatment temperature of 350 ° C. and a rotation speed of 4 rotations / minute, and heat treatment was performed for 10 minutes. Next, the material taken out from the rotary kiln was transferred to a container, and the temperature was raised from room temperature to 250 ° C at 2 ° C.
The temperature was raised at a rate of about 1 / min, and the infusibilizing treatment was carried out at 250 ° C. for 1 hour. After that, 600 in nitrogen atmosphere
A carbonization treatment was carried out at 1 ° C. for 1 hour, and after the heat treatment was completed, excess activated carbon powder was removed by sieving to obtain a hollow activated carbon molded product. Next, this hollow activated carbon molded product was immersed in a 10% solution of polyvinylidene chloride resin in methyl ethyl ketone to sufficiently impregnate the solution, and then titania I was applied to the outer surface of the molded product.
Thoroughly sprinkle T-PC and attach it, then embed it in Titania IT-PC as it is, and 700 in a nitrogen atmosphere.
Heat treatment is carried out at 1 ° C for 1 hour, and after the heat treatment is completed, excess titania IT-PC is removed by sieving to increase the adhesion strength of the titanium dioxide powder to the outer surface of the hollow activated carbon molded product and to increase the polyvinylidene chloride resin powder. Activated carbonized, outer diameter approx. 5
An approximately spherical hollow activated carbon / titanium dioxide composite of mm was obtained.

Example 8 The hollow activated carbon molding obtained in Example 1 was treated with SNO-TEX 20 (a colloidal aqueous solution of silicic acid anhydride manufactured by Nissan Chemical Industries, Ltd .: silicic acid content of about 20).
%) And sufficiently impregnated with SNO-TEX 20. Then, sprinkle TITONO.R-7E on this outer surface sufficiently to make it adhere to it, and then directly use TITONO.R-7E.
It is buried inside and heat-treated at 800 ° C for 1 hour in a nitrogen atmosphere. After the heat-treatment, excess TITONO.
R-7E was removed by sieving to give titanium dioxide powder having a high fixing strength as in Example 2, and an outer diameter of 1200 to 2000.
A spherical hollow activated carbon / titanium dioxide composite having a diameter of μm was obtained.

Example 9 The hollow activated carbon molded article obtained in Example 1 was dipped in a 10% methyl ethyl ketone solution of polyvinylidene chloride resin to be sufficiently impregnated with the solution, and then techpolymer-MBTP was applied to the outer surface thereof. Is thoroughly sprinkled and adhered, embedded in TITONO.R-7E, and subjected to heat treatment at 700 ° C. for 1 hour in a nitrogen atmosphere,
After completion of the heat treatment, the excess TITONO.R-7E was removed by sieving to obtain a spherical hollow activated carbon / titanium dioxide composite having an outer diameter of 1200 to 2000 [mu] m with a high fixing strength of titanium dioxide powder as in Example 2. Obtained.

Example 10 The hollow activated carbon molding obtained in Example 1 was dipped in Sno-Tex 20 to sufficiently impregnate it with Sno-Tex 20, and then the polyvinylidene chloride resin was formed on the outer surface of the product. The powder and TITONO.R-7E were dispersed and mixed at a ratio of 1: 5 (weight ratio), and the powder was thoroughly sprinkled and adhered. The powder was embedded in TITONO.R-7E, 800 ° C. in a nitrogen atmosphere, Heat treatment is carried out for 1 hour, and after the heat treatment is completed, excess TITONO.R-7E is removed by sieving to increase the adhesion strength of the titanium dioxide powder to the outer surface of the hollow activated carbon molded product, and to add polyvinylidene chloride resin powder to the activated carbon. A spherical hollow activated carbon / titanium dioxide composite having an outer diameter of 1200 to 2000 μm was obtained.

<Example 11> The activated carbon molded product obtained in Example 4 was immersed in methyl ethyl ketone to sufficiently impregnate it with methyl ethyl ketone, and then polyvinylidene chloride resin powder and TITONO.R-7E were formed on the outer surface of the product. To 1: 5
The powder mixed and dispersed in (weight ratio) is thoroughly sprinkled and adhered, embedded in TITONO.R-7E, subjected to heat treatment at 700 ° C. for 1 hour in a nitrogen atmosphere, and after the heat treatment, Excessive TITONO.R-7E was removed by sieving to increase the adhesion strength of titanium dioxide powder to the outer surface of the activated carbon molded product and activated carbonization of polyvinylidene chloride resin powder, spherical hollow with an outer diameter of 400 to 900 μm. An activated carbon / titanium dioxide composite was obtained.

A constant amount of each of the products obtained in the above examples was measured with an electromagnetic sieving shaker at a frequency of 300 per minute.
A shaking test was carried out under conditions of 0, amplitude 2 mm, time 5 minutes, use of 50 mesh standard sieve, and by comparing the amount of titanium dioxide powder that had fallen off, the adhesion strength of the titanium dioxide powder to the hollow activated carbon molded product was determined. Evaluated. The evaluation is the ratio of the amount of titanium dioxide powder dropped after the shaking test to the amount of titanium dioxide powder fixed on the outer surface of the hollow activated carbon molded article before the shaking test, and ◎: the falling rate is less than 10%,
◯: Dropout rate is 10% or more and less than 30%, Δ: Dropout rate is 30%
Or more to less than 50%, x: the drop rate is 50% or more. Table 1 shows the results.

[0026]

[Table 1]

[0027]

EFFECT OF THE INVENTION The hollow activated carbon / titanium dioxide composite of the present invention is used to decompose environmental pollutants and the like on the outer surface of a hollow activated carbon molded article having excellent properties such as adsorptivity and lightness by irradiation with light. Titanium dioxide powder having a detoxifying property is fixed, and it may be a functional complex that shares the ability of activated carbon to adsorb harmful substances and the ability of titanium dioxide to decompose harmful substances. Further, according to the production method of the present invention, this hollow activated carbon / titanium dioxide composite can be easily produced without complicated steps.

Claims (3)

[Claims] 1. A hollow activated carbon formed by arranging titanium dioxide powder alone or titanium dioxide powder and another substance on at least the outer surface of a hollow activated carbon molded product comprising activated carbon powder and a carbonized material of a particulate thermoplastic resin. Titanium dioxide complex. 2. A hollow activated carbon molded product obtained by using a particulate thermoplastic resin and an activated carbon powder, mixing the particulate thermoplastic resin and the activated carbon powder, and then melting and carbonizing the particulate thermoplastic resin. Furthermore, a titanium dioxide powder alone is provided on at least the outer surface of the hollow activated carbon molded article,
Alternatively, a composite of titanium dioxide powder and another substance, or a mixture of titanium dioxide powder and another substance is directly or indirectly attached and then heat-treated to fix the titanium dioxide powder directly or indirectly. A method for producing a hollow activated carbon / titanium dioxide composite, which is characterized in that 3. A particulate thermoplastic resin and an activated carbon powder are used, the particulate thermoplastic resin and the activated carbon powder are mixed, and then the particulate thermoplastic resin is melted to produce an activated carbon molded article, Further, a titanium dioxide powder alone, or a composite of titanium dioxide powder and another substance, or a mixture of titanium dioxide powder and another substance is directly or indirectly attached to at least the outer surface of the activated carbon molded product. After that, a method for producing a hollow activated carbon / titanium dioxide composite is characterized in that the activated carbon molded product is hollowed by carbonization heat treatment and the titanium dioxide powder is directly or indirectly fixed.