JPS5921513A - Manufacture of activated carbon having network structure - Google Patents

Abstract

PURPOSE:To obtain activated carbon having a network structure, continuous pores and superior adsorbing power by carbonizing and activating a porous body consisting of synthetic polyvinyl acetal resin, a resin convertible into glassy carbon and fine ceramic powder. CONSTITUTION:PVA, phenolic resin and fine ceramic powder are mixed with a pore forming material and reacted with a cross-linking agent such as formaldehyde to obtain a porous body consisting of synthetic polyvinyl acetal resin and fine ceramic powder, and the porous body is combined with a resin convertible into glassy carbon by thermal decomposition such as phenolic resin. The resulting composite porous body is optionally carbonized by calcination in a nonoxidizing atmosphere, and it is simultaneously carbonized and activated by heating to 500-1,200 deg.C in an atmosphere of steam or gaseous CO2 to obtain activated carbon having a network structure, continuous pores, a uniform pore size distribution, high shape retentivity, large specific surface area and superior adsorbing power. The carbon causes a small pressure loss when a fluid is passed.

Description

DETAILED DESCRIPTION OF THE INVENTION Conventionally, activated carbon has been used in powder or granular form as an adsorbent for various substances, a catalyst carrier, and the like.

Powdered activated carbon has excellent adsorption ability, but has the disadvantages of large pressure loss during fluid permeation, poor regeneration efficiency, and difficult handling. On the other hand, although granular activated carbon is superior to powdered activated carbon in terms of fluid permeability, regeneration efficiency, and ease of handling, it has the disadvantage of inferior adsorption ability, and is also susceptible to vibration and turbulence during use. Due to movement, etc., the filling state of activated carbon becomes uneven in density, and gaps are formed in some parts through which fluid can easily pass, and the activated carbon cannot be used uniformly and effectively over the entire area.

As a means to improve these drawbacks, fibrous activated carbon obtained by carbonizing and activating insoluble fibers or fibers or fiber structures that have been subjected to insolubilization treatment has been proposed. These materials can be in the form of woven or non-woven fabrics and are therefore somewhat easier to handle, but they have drawbacks such as low strength and significantly large pressure loss.

In addition, activated carbon obtained by carbonizing and activating organic polymer foams has been proposed as another method to improve the above-mentioned drawbacks, but in many of these, the foams do not have continuous pores or have a uniform pore size distribution. It has disadvantages such as low porosity, poor morphology, large deformation during carbonization activation, and large weight loss.

The present inventors have developed a new method for producing activated carbon that overcomes the above-mentioned drawbacks by carbonizing and activating a synthetic resin composite porous body with continuous pores made of a polyvinyl acetal-based synthetic resin and a resin that can be converted into glassy carbon by thermal decomposition. We proposed a method for producing network-structured activated carbon. The network activated carbon has excellent adsorption ability, has continuous pores with a uniform pore size distribution, has low pressure loss, does not become denser due to vibration or rocking, and is easy to regenerate. It has characteristics. However, in order to increase the specific surface area of the network activated carbon, if the activation conditions are made stricter and the yield upon activation is lowered,
It has the disadvantage that the specific surface area cannot be increased beyond a certain level because cracks occur in the activated carbon structure.
This tendency was more pronounced as the size of the activated carbon structure became larger.

As a result of intensive research to improve the above-mentioned drawbacks of network activated carbon, the present inventors have discovered a composite porous material with continuous pores made of a polyvinyl acetal synthetic resin, a resin that can be converted into glassy carbon by thermal decomposition, and a fine ceramic powder. The present invention was completed based on the discovery that network-structured activated carbon with excellent properties can be obtained by carbonizing and activating the activated carbon.

The object of the present invention is to have continuous pores with uniform pore size distribution, low pressure loss during fluid permeation, and good shape retention.
Another object of the present invention is to provide a method for producing network activated carbon having a large specific surface area and excellent adsorption ability.

The above purpose is achieved by carbonizing and activating a composite porous body with continuous pores made of a polyvinyl acetal synthetic resin, a resin that can be converted into glassy carbon by thermal decomposition, or a resin containing these as its main component, and a fine ceramic powder. achieved.

The manufacturing method of the composite porous body having continuous pores of the present invention can be roughly divided into two. The first method is to first create a polyvinyl acetal synthetic resin porous body with continuous pores containing fine ceramic powder, impregnate the porous body with a resin that can be converted into glassy carbon by thermal decomposition, and then harden it. It's a method.

The second method is to mix a phenolic resin, which is one of the resins that can be converted into glassy carbon, with polyvinyl alcohol, fine ceramic powder, and a pore-forming material, and then react and cure the mixture in the presence of a crosslinking agent.

In order to produce a porous polyvinyl acetal synthetic resin containing fine ceramic powder in the first method, polyvinyl alcohol and fine ceramic powder are mixed with aldehydes as a crosslinking agent, starch as a pore forming material, water-soluble salts, etc. and a catalyst such as sulfuric acid, cross-linked and molded, and after solidification, water-soluble substances are eluted with water to provide continuous pores.

The polyvinyl alcohol used in the production of the polyvinyl acetal synthetic resin porous body containing the above-mentioned ceramic fine powder has a degree of polymerization of 100 to 5000 and a degree of saponification of 70% or more, and may also be partially modified with carboxyl groups, etc. Suitably used.

Ceramic fine powders include oxides such as silica, alumina, aluminum silicate, magnesia, zirconium oxide, zirconium silicate, and titanium oxide, Kibushi clay,
Clays such as frog's eye clay and clay chamotte, kaolin, diatomaceous earth, montmorinite, bentonite, silicon carbide, silicon nitride, aluminum phosphate and the like are suitable, but are not limited to these.

These ceramic fine powders may be used alone, or two or more types of fine powders may be used in combination.

Among them, fine powders containing acid-soluble alkaline components such as montmolinite and bentonite react with the acid added as a catalyst during the production of the composite porous body, and the ceramic fine powder and synthetic resin are uniformly mixed. This is particularly preferred since it forms a strong composite porous body.

Examples of the aldehydes used as crosslinking agents include formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, octylaldehyde, 2-ethylhexylaldehyde, glyoxal, acrolein, and benzaldehyde.

As the powder or granule for providing continuous pores, starch or other organic fine powder, water-soluble metal salt, or the like is used, and the powder or granule is appropriately selected so as to provide the desired pore size.

A more specific description of the method for producing a ceramic-containing polyvinyl acetal synthetic resin porous body using the above-mentioned polyvinyl alcohol, ceramic fine powder, and pore-forming phase is as follows. That is, a predetermined amount of polyvinyl alcohol aqueous solution is heated while stirring, and fine ceramic powder previously dispersed in water is added thereto and stirred.
Next, an aqueous solution or aqueous dispersion of a pore-forming material such as wheat flour starch is added, thoroughly stirred, and after cooling to about 40°C, aldehydes as a crosslinking agent and sulfuric acid as a catalyst are added and mixed uniformly. Cast into a mold of the desired shape. This is further heated to cause a reaction, and after the reaction is completed, the molded product taken out from the mold is washed with water to wash away aldehydes and acids that have not reacted with the pore-forming material.

The shape of the porous body can be freely selected from plate-like, cylindrical, cylindrical, etc. depending on the purpose, use, and required performance.

Among the polyvinyl acetal synthetic resin porous bodies containing ceramic fine powder obtained in this way, polyvinyl formal synthetic resin porous bodies having a specific network structure,
Or polyvinylbenzal synthetic resin porous material is particularly suitable.

Examples of resins that can be converted into glassy carbon that can be impregnated into the polyvinyl acetal synthetic resin porous body containing shellac fine powder produced as described above include phenolic resins such as resol resins and novolac resins, and furan resins. Although these may be used alone or in combination, resol resins are most preferred, and novolac resins are second most preferred, considering workability such as resin curing operations.

Resole resin is an initial product produced by reacting phenols with aldehydes in the presence of a basic catalyst, and is usually a self-thermal crosslinking resol with a molecular weight of up to about 600 and rich in methylol groups. be. In particular, when manufacturing resol resin, for 1 mole of phenol,
A water-soluble resol is obtained by reacting 1.5 to 3.5 moles of aldehydes in the presence of a slightly excess alkali catalyst.

Phenols used in the production of resol resins most commonly include phenol and cresol. However, other phenols can also be used, such as phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,5-xylenol, 2,4- xylenol, 2,6-xylenol, 3
, 4-xylenol, 3,5-xylenol, o-ethylphenol, m-ethylphenol, p-ethylphenol, p-phenylphenol, p-tert-butylphenol, p-tert-aminophenol, bisphenol A, resorcinol and these Examples include mixtures of phenols.

Formaldehyde is the most common aldehyde used for polycondensation with this phenol. However, monoaldehydes and dialdehydes such as paraformaldehyde, hexamethylenetetramine, furfural and cultaraldehyde, azibaldehyde and cryoxal may also be used.

Basic catalysts used in the resol resin synthesis reaction include caustic alkali, alkali carbonate, barium hydroxide, calcium hydroxide, ammonia, quaternary ammonium compounds,
Known amines may be used, and caustic soda or ammonia is most commonly used.

The novolak resin is prepared by combining the same phenols used in the production of the resol resin and the same aldehydes used in the production of the resol resin with oxalic acid,
Produced by reaction with heating in the presence of an acidic catalyst such as organic acids such as formic acid, acetic acid, halogenated acid, and para-toluenesulfonic acid, and inorganic acids such as hydrochloric acid, sulfuric acid, perchloric acid, and phosphoric acid. It is an uncured and meltable thermoplastic resin with a molecular weight of about 300 to 2,000.

Examples of the furan resin include furfuryl alcohol resin, furfuryl alcohol phenol resin, furfural resin, furfural phenol resin, and furfural ketone resin. As a curing agent for these resins, for example, organic acids such as aniline hydrochloride and para-toluenesulfonic acid can be used.

To produce a composite porous body by applying a resin that can be converted into glassy carbon to the polyvinyl acetal synthetic resin porous body having continuous pores containing the aforementioned ceramic fine powder,
Various methods can be applied, but most commonly, a polyvinyl acetal synthetic resin porous body containing ceramic fine powder having a predetermined shape, size, pore diameter, and porosity is mixed with a phenolic resin solution, furan resin, etc. It may be immersed in a solution or the like.

A phenol resin solution such as a resol resin or a novolak resin can be dissolved in an appropriate amount in a solvent such as methanol or acetone to prepare a phenol resin solution with a predetermined concentration. Moreover, a water-soluble resol can also be used as the resol resin.

In the case of a resol resin, if necessary, a small amount of an organic acid such as paratoluenesulfonic acid or phthalic acid may be added in advance to the solution as an acid catalyst for curing.

In the case of a novolak resin, a novolak resin solution prepared by dissolving an appropriate amount of a crosslinking agent in a solvent such as methanol or acetone may be used.

As a crosslinking agent, hexamethylenetetramine can be used most commonly, but aldehydes such as paraformaldehyde, glutaraldehyde, azibaldehyde, and glyoxal, and acids or alkalis may also be used in combination. .

Alternatively, after a porous body is impregnated with a novolak resin in advance, it may be cured by heating in an aqueous solution containing hexamethylenetetramine, an acid or an alkali, and an aldehyde.

In the case of furan resin, use a solution in which the furan resin is dissolved in a solvent such as acetone or benzene, and a curing agent such as aniline hydrochloride or paratoluenesulfonic acid is mixed in at about 0.2 to 1% of the resin solid content. good.

After adjusting the resin adhesion amount by centrifugation on a polyvinyl acetal synthetic resin porous body impregnated with a resin that can be converted into glassy carbon by thermal decomposition such as phenol resin or furan resin by this method, it is heated at room temperature or under heating. It is dried and further cured at a high temperature of 120 to 180°C. Through this drying and curing process, the impregnated resin that has permeated into the porous body of polyvinyl acetal synthetic resin containing ceramic is integrated with the porous body to form a composite porous body having continuous pores, and through carbonization and activation described below, the impregnated resin is This results in activated carbon with a network structure that retains the network structure of the synthetic resin porous body.

A second method for producing the composite porous body having continuous pores of the present invention includes a method in which polyvinyl alcohol, phenol resin, and fine ceramic powder are mixed together with a pore-forming material and reacted in the presence of a crosslinking agent. The polyvinyl alcohol, fine ceramic powder, crosslinking agent, pore-forming material, etc. used in this method may be the same as those used in the production of the polyvinyl acetal synthetic resin porous body containing fine ceramic powder according to the first method described above. As the phenol resin, water-soluble resols and phenol resin powders that have good miscibility with polyvinyl alcohol, crosslinking agents, and pore-forming materials are suitable. As the phenol resin powder, cured phenol resin powder, phenol resin short fibers, pulverized phenol resin fiber fine powder, etc. can be used, but particularly reactive granular or powdered phenol resin is preferable.

The reactive granular or powdered phenolic resin of the present invention is a granular or powdered resin made of a condensate of phenols and formaldehyde, and the KBr of the resin is
1600c in infrared absorption spectrum by tablet method
m-1 (absorption peak attributed to benzene) is D1600, and the highest absorption intensity in the range of 990 to 1015 cm-1 (absorption peak attributed to methylol group) is D990 to 1015, 890 cm-1 (benzene nucleus). Absorption peak of isolated hydrogen atom) When expressed as absorption intensity D800, D990~1015/D1600=0.2~9.0, D
890/D1600 = 0.09 to 1.0 is a granular or powdered phenol/formaldehyde resin,
Preferably D990-1015/D1600=0.3-7.0D8
90/D1600=0.1-0.9, particularly preferably D990-1015/D1600=0.4-5.0D8
It is a granular or powdery phenol-formaldehyde resin having a ratio of 90/D1600 of 0.12 to 0.8.

In the infrared absorption spectrum, the D160O peak shows absorption attributed to the benzene nucleus, and D990 to 1015
It is already widely known regarding phenol-formaldehyde resins that the peak D890 shows an absorption attributed to a methylol group, and the peak D890 shows an absorption attributed to an isolated benzene nucleus and a hydrogen atom.

The reactive granular or powdered phenol resin used in the present invention has D990~1015/D1600=0.2~
The characteristic value of 9.0 indicates that the resin contains at least some amount of methylol groups, and that the methylol group content can be adjusted within a fairly wide range. Especially D990-1015=0.3-7.0, particularly 0.4-5
．． The preferred resin for use in the present invention, 0, contains a moderate concentration of methylol groups and is more stable.

Furthermore, the resin has D89 in the infrared absorption spectrum.
0/D1600=0.09-1.0, more preferred resin is D890/D1600=0.1-0.9, especially 0.12
The fact that the resin exhibits a characteristic of ˜0.8 indicates that the reactive sites (ortho and para positions) of the phenol molecules involved in the reaction are appropriately blocked by methylene bonds or methylol groups.

To produce a composite porous material by the second method, first, a predetermined amount of polyvinyl alcohol aqueous solution is heated while stirring, a water-soluble phenol resin is added and mixed, and if necessary, reactive granules or Add powdered phenolic resin or other phenolic resin powder and mix thoroughly. To this are added pore-forming materials such as fine ceramic powder dispersed in water and wheat flour starch as an aqueous solution or dispersion, and the mixture is stirred and cooled to about 40°C. Add sulfuric acid, mix uniformly, transfer to a mold, and react. After the reaction is completed, the molded product taken out from the mold is washed to wash away pore formation and unreacted aldehydes and acid.

As mentioned above, the composite porous body of the present invention can be produced by two methods, but the continuous porosity of the composite porous body is usually 50 to 9.
2%, preferably 70-92%, most preferably 80-92%
It is 92%.

Furthermore, the content of resin that can be converted into glassy carbon in the composite porous body produced by the above two methods is usually 25 to 25%.
85% by weight, preferably 40-82%, most preferably 55-80%. The content of the ceramic fine powder in the composite porous body is usually 3 to 10% by weight, preferably 4 to 9% by weight, and most preferably 4 to 8% by weight.

If the content of the resin that can be converted into glassy carbon in the composite porous material is extremely low, the weight loss and size reduction during the carbonization and activation processes become large, resulting in non-uniform deformation. Since the strength of the network activated carbon is significantly reduced, it cannot be put to practical use. If the content of the resin that can be converted into glassy carbon is excessive, exceeding 85% by weight, the porosity of the composite porous body will decrease, and the porosity of the network-structured activated carbon obtained by carbonization activation will also decrease, causing the fluid to deteriorate. The pressure loss during permeation increases and the properties of activated carbon having continuous pores are lost. When the content of the resin that can be converted into glassy carbon in the composite porous body is 25 to 85% by weight, dimensional changes during carbonization activation are small and yield is high, and the continuous porosity is large and pressure loss is reduced. Activated carbon with a low network structure can be obtained.

The effect of mixing fine ceramic powder into the composite porous body of the present invention is to suppress the occurrence of cracks due to stress generated during carbonization activation of the composite porous body. In a synthetic resin porous body that does not contain fine ceramic powder, cracks are more likely to occur as the activation conditions become more severe and the specific surface area increases, and as the sample shape becomes larger and more complex, but it is important to mix an appropriate amount of fine ceramic powder. This makes it possible to suppress the occurrence of cracks. When the content of the fine ceramic powder in the composite porous body is less than 3%, the effect of suppressing cracks by the fine ceramic powder is hardly recognized. Furthermore, if the content of the ceramic fine powder exceeds 10%, the proportion of the ceramic fine powder in the network structure activated carbon after carbonization activation becomes too large, the specific surface area of the activated carbon structure decreases, and the adsorptivity decreases. Problems arise, such as the strength being significantly lowered. When the content of the ceramic fine powder in the composite porous body is 3 to 10% by weight, the strength and specific surface area can be maintained without cracking during carbonization activation even in samples with complex shapes and large dimensions. Activated carbon with a large network structure is obtained.

Furthermore, other synthetic resins such as melamine resins, epoxy resins, mixtures of vinyl polymers and divinyl compounds, urea resins, unsaturated polyester resins, pitch, tar, etc. are applied to the above composite porous body. You may. These resins can be easily applied, for example, by impregnating the composite porous body with a resin solution or a mixture of these resins and a resin that can be converted into glassy carbon by thermal decomposition.

After producing the composite porous body as described above, the composite porous body is subjected to an activation treatment. The activation treatment may be performed by either a gas activation method or a chemical activation method. In the gas activation method, carbonization and activation can be performed in two steps, or carbonization and activation can be performed in one step.
They can also be performed simultaneously as a process. When carbonization and activation are performed separately in the gas activation method, the combined The porous body is usually carbonized and fired at a temperature of 600°C or higher. Next, activation treatment is performed at a predetermined temperature in an atmosphere containing steam, carbon dioxide, air, or a mixture thereof. The temperature and time of the activation treatment are appropriately determined depending on the porosity, pore diameter, shape, desired specific surface area, atmosphere, etc. of the composite porous body.

For example, in the case of water vapor or carbon dioxide atmosphere, it is usually 50
Activation treatment is performed at 0 to 1200°C, preferably 700 to 1000°C, for several minutes to several hours.

When carbonization and activation are performed simultaneously using a gas activation method, the temperature of the composite porous body is generally raised in a steam or carbon dioxide atmosphere, and the process is carried out at a predetermined temperature of 500 to 1200° C. for a predetermined period of time.

In the case of the chemical activation method, carbonization and activation are performed simultaneously by firing a composite porous body with continuous pores containing zinc chloride, phosphoric acid, potassium sulfide, etc. at 400 to 1000°C in a non-oxidizing atmosphere. be able to.

To impart a chemical to the composite porous material, for example, the composite porous material may be impregnated with an aqueous solution of Zncl2 and then dried, or a Zncl2 aqueous solution may be applied to a polyvinyl acetal-based synthetic resin porous material containing ceramic fine powder having continuous pores. After impregnation and drying, a resin that can be converted into glassy carbon may be applied.

Since the composite porous body of the present invention contains fine ceramic powder, activation progresses uniformly throughout the sample even in large-sized samples with complex shapes, and the specific surface area is reduced without causing cracks in the sample. It is possible to obtain activated carbon with a network structure that is large and strong.

In addition, the network activated carbon is an activated carbon with a high continuous porosity consisting of uniformly distributed pores, and has both the adsorption function and filter function of ordinary activated carbon.

Such network activated carbon is effective as various adsorbents and can also remove fine particles in liquids and dust in the air, so it is significantly simpler than the conventional method of using an activated carbon layer and other filters. be. Furthermore, the activated carbon does not have problems such as pulverization or uneven density during use or transportation, unlike granular or fibrous activated carbon, and
It has the advantage of significantly lowering pressure loss. Further, depending on the use, the network activated carbon may be used after its surface is coated with a hydrophilic acrylic polymer, collodion, gelatin, or the like.

The activated carbon having a network structure having continuous pores of the present invention takes advantage of the above-mentioned advantages and can be used extremely effectively for adsorption of various harmful gases and various compounds, purification of contaminated air, treatment of sewage, and the like. Furthermore, it is highly useful as an easy-to-handle activated carbon in decolorizing, deodorizing, and colloid removal in pharmaceutical manufacturing processes, and in the production of industrial ultrapure water. Furthermore, the activated carbon is
It forms a network skeleton and does not shed carbon powder, making it ideal as activated carbon for artificial organs.

In addition to the above, if the network-structured activated carbon supports an acid such as sulfuric acid, it will be possible to obtain a carbon with excellent ability to remove basic compounds such as ammonia and various amines from the air. By supporting hydroxides, carbonates, or manganese oxides of alkali metals such as hydroxides, carbonates, or manganese oxides, products with better ability to remove sulfur dioxide gas, nitrogen oxides, etc. can be obtained, and can be used for air purification. In addition, palladium is added to the activated carbon.
When a noble metal such as platinum is supported, a catalyst filter capable of oxidizing carbon monoxide, hydrocarbons, etc. at low temperatures can be obtained. Furthermore, the activated carbon is also effective as activated carbon for canisters to suppress evaporation loss of fuel for automobiles.

The present invention will be specifically explained below using Examples.

Example 1 Polyvinyl alcohol (PVA) with a degree of polymerization of 1700 and a degree of saponification of 99%, fine silica sand powder (average particle size 30 μm)
, reactive granular phenolic resin (average particle size 40μ
m), water-soluble resol resin (Sumitomo Turez Co., Ltd. product,
PR961A (solid content: 65% by weight) was calculated so that the solid content ratio was as shown in Table 1 and the total solid content ratio was 2 kg.

First, PVA is dispersed in water, heated and dissolved, and then a reactive granular phenol resin that has been previously dispersed in water is mixed.
A water-soluble resol resin and fine silica sand powder were added and thoroughly stirred and mixed while heating. When the temperature reached 60°C, an aqueous dispersion of 340 g of wheat flour starch having a predetermined particle size was further added and heated with stirring until the temperature reached 70 to 80°C. After cooling this mixture to 40°C, 900 ml of 37% formalin and 5
600 ml of 0% sulfuric acid was added and mixed, and a small amount of water was added to adjust the volume of the mixed solution to 10 liters. The mixed solution was poured into a cylindrical mold, heated at 60°C for 18 hours, taken out from the mold, washed with a shower for 24 hours, and made into a mold with an outer diameter of 200 mm.
A composite porous body having continuous pores containing fine silica sand powder and having an inner diameter of 100 mm and a length of 400 mm was obtained. The average pore diameter of the composite porous body was 15 μm.

This composite porous body was placed in an electric furnace and heated to 100°C in a nitrogen atmosphere.
The temperature was raised to 850°C at a heating rate of /m for carbonization, and then the nitrogen gas containing water vapor obtained by flowing nitrogen gas into 80°C hot water at a flow rate of 10 l/min was introduced into the electric furnace. The activated carbon shown in Table 1 was obtained by activating it at 850° C. for a predetermined time.

As can be seen from Table 1, even in relatively large samples such as those of this example, network-structured activated carbon with a large specific surface area and good shape retention was obtained by mixing an appropriate amount of semilac fine powder. If the silica sand content is too low, cracks will occur, and if the silica sand content is too high, the carbon content in the network activated carbon will be too low, resulting in a decrease in strength and a tendency to collapse.

Table 1 ○ Yield = (activated carbon weight) / (composite pore weight before activation)
×100(%)○Specific surface area was measured by BET method.

Example 2 Polyvinyl alcohol with a degree of polymerization of 1000 and a degree of saponification of 99% was dispersed in water, then heated and dissolved, and bentonite fine powder (manufactured by Toyojun Yoko Co., Ltd., trade name Bengel), which had been previously dispersed in water, was prepared. The mixture was added and mixed by stirring. When the temperature of the mixture reached 60°C, an aqueous dispersion of potato starch was added and heated to 70 to 80°C with stirring. After cooling this liquid mixture to 40°C, a 30% aqueous benzaldehyde solution and a 50% aqueous sulfuric acid solution were added and mixed uniformly. The blended amounts of each raw material are a total of 600 g of polyvinyl alcohol and fine bendonite powder, 260 g of potato starch, 300 ml of 30% benzaldehyde, and 440 ml of 50% sulfuric acid.Finally, a small amount of water is added to the mixed solution to make a liquid volume of 5 liters. I adjusted it so that The solution was poured into a mold with an outer diameter of 100 mmφ and a length of 500 mm, heated at 60°C for 20 hours, and then demolded.
Starch and unreacted substances were washed away to obtain a polyvinylbenzal porous body containing fine bentonite powder. The average pore diameter of the porous body was 30 to 50 μm.

The polyvinylbenzal porous body containing the above bentonite fine powder is immersed in a furan resin with a solid concentration of 40% (manufactured by Hitachi Chemical Co., Ltd., Hitafuran 302, containing 0.2% curing agent) diluted with acetone. After squeezing to a resin adhesion amount of
It was cured at ℃ for 30 minutes to obtain a composite porous body.

The composite porous body containing a predetermined amount of furan resin thus obtained was placed in an electric furnace, heated to 650°C at a rate of 150°C/hr in a nitrogen atmosphere, and then heated for a predetermined time in a steam atmosphere. Activation was carried out while raising the temperature to 900°C. A steam atmosphere was created by introducing nitrogen gas, which was flowed into hot water at 80° C. at a flow rate of 10 l/min, into an electric furnace. Table 2 shows the physical properties of the obtained network activated carbon.

Table 2 As can be seen from Table 2, in Sample 1, in which the furan resin content was too low, the sample deformed unevenly during activation, and good network structure activated carbon could not be obtained. In addition, in sample 6, which had too much furan resin content, the continuous porosity was low, making it difficult for uniform activation to proceed to the inside of the sample, resulting in large variations in surface area depending on location. In addition, the surface area of the obtained activated carbon was small and the continuous porosity was low, so the pressure loss of the fluid was large and it could not be put to practical use.

Samples 2 to 5 containing an appropriate amount of furan resin gave activated carbon with a good network structure.

Example 3 In the same manner as in Example 1, Kibushi clay (average particle size 20 μm) was used as the ceramic fine powder and n-butyraldehyde was used as the crosslinking agent to produce 42% by weight of polyvinyl butyral and 8% by weight of Kibushi clay. %, 40×400×30 consisting of 50% by weight of reactive granular phenolic resin
A 0 mm flat plate-like composite porous body (average pore diameter 20 μm) was prepared.

Furthermore, the composite porous body was mixed with a resol resin methanol solution (Gun-ei Chemical Industry Co., Ltd. product PL-32) with a solid content concentration of 35% by weight.
06), centrifuged, and dried and hardened at 130° C. for 2 hours. The obtained composite porous body was made of polyvinyl butyral 2
5% by weight, 5% by weight of Honbushi clay, and 70% by weight of total phenolic resin.

This composite porous body was immersed in a 50% by weight aqueous solution of Zncl, dried, and placed in an electric furnace at 700°C for 45 minutes in a nitrogen atmosphere.
The specific surface area was increased to 131 by holding for a minute and washing with water after cooling.
A good network activated carbon having a continuous porosity of 88% was obtained.

Claims (12)

[Claims] (1) It is characterized by carbonizing and activating a composite porous body having continuous pores made of a polyvinyl acetal-based synthetic resin, a resin that can be converted into glassy carbon by thermal decomposition, or a resin whose main component is a ceramic powder. A method for producing network activated carbon with continuous pores. (2) The composite porous body having continuous pores is a polyvinyl acetal synthetic resin porous body containing semilac fine powder, and a resin that can be converted into glassy carbon by thermal decomposition is applied to the polyvinyl acetal synthetic resin porous body containing semilac fine powder. A method for producing network activated carbon as described in (1). (3) The method for producing network activated carbon according to claim (2), wherein the polyvinyl acecool-based synthetic resin is polyvinyl formal or polyvinyl benzal. (4) The composite porous body having continuous pores is a porous body obtained by mixing polyvinyl alcohol, phenol resin, and ceramic fine powder method with a pore-forming material, and reacting the mixture with a crosslinking agent. A method for producing network activated carbon according to any of paragraph (3). (5) A porous body with continuous pores is obtained by mixing polyvinyl alcohol, phenol resin, and fine ceramic powder with a pore-forming material and reacting with a crosslinking agent, which is then converted into glassy carbon by thermal decomposition. Claims (1) to (1) to (1) are coated with a resin that can
3) A method for producing network activated carbon according to any one of paragraphs 3) to 3). (6) The method for producing network activated carbon according to claim (2) or (5), wherein the resin that can be converted into glassy carbon by thermal decomposition is a phenolic resin or a furan resin. (7) The method for producing network activated carbon according to claim (4) or (5), wherein the crosslinking agent is formaldehyde or benzaldehyde. (8) Production of network activated carbon according to claim (1), wherein the content of the resin that can be converted into glassy carbon by thermal decomposition in the composite porous body having continuous pores is 25 to 35% by weight. Law. (9) The content of the fine ceramic powder in the composite porous body having continuous pores is 3 to 10% by weight.
1) A method for producing network activated carbon as described in section 1). (10) Carbonization and activation are carried out by carbonizing and firing the composite porous body in a non-oxidizing atmosphere, and then heating and activating it at 500 to 1200°C in a steam or carbon dioxide atmosphere. 2. Method for producing network activated carbon as described in Section 1. (11) Carbonization and activation are carried out by heating the composite porous body at 500 to 1200°C in a steam or carbon dioxide atmosphere, and carbonization and activation are carried out in Claim No. 1
2. Method for producing network activated carbon as described in Section 1. (12) After applying zinc chloride, phosphoric acid, or potassium sulfide to the composite porous material, carbonize and activate it in a non-oxidizing atmosphere.
A method for producing network activated carbon according to claim (1), which is carried out by heating to 00 to 1000°C and carbonizing and activating.