JPH07155609A - Production of high capacity carbon material - Google Patents

Abstract

PURPOSE:To produce a carbon material having a high specific surface area and showing high decomposition activity to an inorg. or org. substance by adding a magnesium or silver compd. to a carbonaceous material having pores and a predetermined specific surface area or more and heat-treating this carbonaceous material in an oxidizable gas atmosphere. CONSTITUTION:A high capadity carbon material is produced by adding a magnesium or silver compd. to a carbonaceous material having pores and a specific surface area of 100m<2>/g or more and heat-treating this carbonaceous material in an oxidizable gas atmosphere. As the carbonaceous material becoming a raw material, one with a specific surface area of at least 100m<2>/g or more is used. When a metal compd. is added, an aq. soln. of a magnesium or silver compd. is added to the sufficiently degassed raw carbonaceous material to be mixed therewith and the resulting mixture is allowed to stand to cool to uniformly infiltrate the metal compd. throughout the pores of caboneceous material. In a heat treatment process, the carbonaceous material to be treated is uniformly heated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high-performance carbon material having a high resolving power for a COD source material and a high specific surface area. The carbon material of the present invention has a high decomposing ability for COD source substances, and has extremely excellent decomposing activity for inorganic substances such as hydrogen peroxide and human lazine and organic substances. It is useful as a catalyst.

[0002]

In general, activated carbon is used for separating hydrocarbons, refining industrial gas, liquid phase refining in food industry, chemical industry, water treatment agent, etc., as well as air molecule sieving material, precious metal recovery from precious metal salt solution, etc. In addition to adsorption, as a catalyst carrier and CO
It is widely used as a catalyst for decomposing D source materials.

Generally, activated carbon is a gas activation method in which coconut husk, wood, coal, coal and petroleum cocos, organic resin, etc. are used as raw materials, carbonized, and then reacted with an oxidizing gas to form fine pores, Alternatively, chemical activation by impregnating a carbonaceous material from the above raw materials with a chemical such as zinc chloride, acid or alkali vapor and heating in an inert gas to form fine pores by dehydration and oxidation reaction of the chemical The law is widely known. (For example, Japanese Patent Publication No. 62-61529, U.S. Pat. No. 3,624,004, U.S. Pat. No. 3,642,657.
No. 3,833,514, Japanese Patent Laid-Open No. 1-2304.
No. 14, JP-A-2-97414)

Further, a method of activating a carbon catalyst by adhering a metal catalyst to the carbon particles to obtain a carbon material having a high adsorptivity in a short time has been reported in JP-A-1-141814 and JP-A-1-141815. However, the adsorption capacity of the carbon material obtained by such a method is not so different from that of the known carbon material for adsorption, and it is not sufficient to be a high performance carbon material.

Further, the highly active hydrogen peroxide decomposition catalyst disclosed in Japanese Patent Application Laid-Open No. 5-811 has a considerably high ability to decompose peroxide water, which uses a protein-containing sludge or waste material as a raw material. Therefore, there is a problem that odor is generated during manufacturing.

For example, not only is COD increased when a waste liquid containing an inorganic substance or an organic substance such as hydrogen peroxide or human lazine is discharged as it is, but also when the waste liquid is mixed with a biological activated sludge treatment device during treatment of the waste water, hydrogen peroxide In the case of contained wastewater, oxygen gas generated by decomposition causes suspension to float, causing various troubles such as deterioration of water quality of treated water. Therefore, it is necessary to decompose and discharge these waste liquids in advance, and there is a method of utilizing activated carbon as the decomposition method.

Currently, as a commercially available activated carbon having a hydrogen peroxide decomposing ability, an activated carbon having a specific surface area of about 1000 m ² / g is known. However, such commercially available activated carbon does not always have sufficient hydrogen peroxide decomposition activity, has a short catalyst life, and is not sufficient for industrial use.

[0008]

However, the production of high specific surface area activated carbon by the above-mentioned alkali vapor activation method is
Since it is necessary to add an alkali metal compound such as potassium hydroxide to the carbonaceous material, preferably in a large excess of 2 times or more, corrosion of the device in the firing step is caused, and the carbonaceous material and the alkali metal compound are added. It is difficult to handle because there is a problem that the mixture with the compound sticks during firing and the flowability is poor and the device is clogged. In addition, since a large excess of alkali is used, it is necessary to recover and reuse the residual alkali from the economical aspect, which has a drawback that the manufacturing process becomes complicated. Further, although this activated carbon has a high specific surface area, it has almost no decomposition performance for the COD source substance. Under these circumstances, there has been a demand for a high-performance carbon material which is a manufacturing method that is easy to carry out industrially and has a high decomposition performance for the COD source substance.

The present invention solves various problems recognized in such conventional methods, and has a high specific surface area and a carbon material having a high decomposition activity for an inorganic substance or an organic substance such as hydrogen peroxide or hydrazine. To provide a method of manufacturing.

[0010]

In view of the current state of the art as described above, the present inventor has conducted earnest research on a method for producing a high-performance carbon material having a high decomposition performance for COD substances, and as a result, has pores. It was found that a high-performance carbon material can be obtained by adding a certain kind of metal compound to a carbonaceous material and then heat-treating it, and made the present invention.

That is, the present invention is a method for producing a high-performance carbon material, which comprises adding a magnesium compound or a silver compound to a carbonaceous material having pores and then heat-treating it in an oxidizing gas atmosphere.

The present invention will be described in detail below. First, as the raw material carbonaceous material in the present invention, a specific surface area of 100
It is necessary to have pores of m ² / g or more. If a carbonaceous material having a specific surface area of less than 100 m ² / g is used, a high performance carbon material cannot be obtained.

The carbonaceous material used as a raw material in the present invention is
A material having pores having a specific surface area of at least 100 m ² / g is used. Such carbonaceous material is coconut husk,
Plant-based carbonaceous materials such as barley, chaff, sawdust, wood, and pulp effluent, and heavy bituminous carbonaceous materials such as coal, petroleum, cokes thereof, and pitch are available. The shape of the raw carbonaceous material is not particularly limited, and any of powdery, crushed, granular, and cylindrical shapes can be used.

As the particle size, either coarse particles or fine particles can be used within a size range of 1 to 300 mesh, but the smaller the particle size, the shorter the activation time for heat treatment in an oxidizing gas atmosphere. It is possible to do so, which is preferable. However, even if the particle size is large, a high performance carbon material can be obtained if the heat treatment time is sufficiently long. Further, the method of the present invention does not necessarily need to be molded because a high-performance carbon material can be produced while maintaining the shape of the raw material, and there is no problem of reduction of specific surface area due to molding with a binder or the like, which is industrially advantageous. It is a manufacturing method.

In the method of adding a metal compound in the present invention, first, the raw material carbonaceous material is sufficiently degassed, and then an aqueous solution of a magnesium compound or a silver compound is added to the degassed raw material carbonaceous material and dissolved and mixed. It is allowed to cool and the metal compound is uniformly impregnated and supported in the entire pores. As the above-mentioned degassing method, generally, a predetermined amount of water is added to the raw carbonaceous material and the mixture is boiled for 10 minutes to 3 hours, preferably 20 minutes to 2 hours with stirring. The quality material may be degassed under vacuum.

As the magnesium compound or silver compound in the present invention, magnesium or silver oxide,
Inorganic acid salts such as sulfides, halides, sulfates, nitrates, phosphates and carbonates, organic acid salts such as formates, acetates, oxalates, tartrates and lactates, and alcoholates. .

Typical examples of the magnesium compound include magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium carbonate, magnesium phosphate, magnesium acetate, magnesium oxalate, magnesium tartrate, magnesium lactate, and magnesium orthosilicate.

Further, as typical compounds of silver compounds,
Silver fluoride, silver chlorate, silver perchlorate, silver iodide, silver sulfate,
Examples thereof include silver nitrate, silver carbonate, silver acetate, silver tartrate, silver cyanide, diammine silver salt, and 1,10 phenanthroline silver. The insoluble compound is preferably dissolved in an acid before use so that it can be uniformly supported.

In the present invention, the magnesium is used in a weight ratio of 1: 0.001 to 1: 0.5 with respect to the carbonaceous material,
Preferably it is added in the range of 1: 0.01 to 1: 0.3.

The weight ratio of the silver compound to the carbonaceous material is 1: 0.001 to 1: 0.1, preferably 1: 0.
It is added in the range of 01 to 1: 0.09.

If the amount of the metal compound added is less than the above range, sufficient activation cannot be performed and the desired high specific surface area cannot be obtained. When the amount exceeds the above range, the above range is practical because the formation of pores having a specific surface area of 2800 m ² / g or more is not promoted and the yield is reduced. In the case of a silver compound, it is not preferable to use the silver compound in an amount exceeding the above range, for example, when it is used as an antibacterial agent for waterworks, the amount of silver deposited increases.

Further, the impregnation time of the magnesium compound and the silver compound into the carbonaceous material depends on the kind of the compound used, the state of the solution, the mixing ratio of the carbonaceous material and water, or the addition amount and concentration of the metal compound. , Generally 10 minutes ~
It is in the range of 30 hours, preferably 30 minutes to 25 hours.

The mixture thus prepared is filtered,
It is washed with water and dried under reduced pressure to obtain a carbonaceous material impregnated with and supported by a metal compound. The excess metal compound that is not impregnated in or supported by the carbonaceous material can be reused by circulating the filtrate. If desired, it is not always necessary to carry out washing with water and drying after impregnation and supporting, and it may be subjected to the next step as it is after filtration.

Next, the product is heated and activated in an oxidizing gas atmosphere. Water vapor, carbon dioxide, oxygen, ozone, nitrogen dioxide and the like can be used as the oxidizing gas atmosphere. Further, these gases may be mixed with a combustion gas or an inert gas and used. In particular, it is preferable to use water vapor, carbon dioxide, and a mixture of these gases with a combustion gas or an inert gas. In addition,
In an atmosphere of an inert gas such as nitrogen or argon, a high performance carbon material having a high specific surface area and a high decomposition performance for a COD source substance cannot be obtained, which is not preferable.

The temperature of the heat treatment in the activation step in the present invention is generally 600 ° C to 1200 ° C, preferably 700 ° C to 1100 ° C. The holding time at the heat treatment temperature is usually 30 minutes to 5 hours, preferably 1 to 4 hours. The higher the treatment temperature and the longer the holding time, the higher the performance carbon material can be obtained, but the yield tends to decrease, and the above range is preferable.

In the method of the present invention, the heat treatment step may be carried out by any method, but it is preferable that the carbonaceous material to be treated is uniformly heated, such as a mobile type, a rotary type and a flow type. Therefore, it is preferable that the heating method be an internal heating type or an external heating type. Further, the heat treatment step can be carried out by either a batch system or a continuous system, but particularly when the carbonaceous material to be treated is rich in fluidity, it is practical to carry out it in a continuous system because the operation is easy. Target.

After completion of the heat treatment, the product is taken out from the reaction tube and dried to obtain the target high-performance carbon material.
The obtained carbon material can be granulated into a product, but in the method of the present invention, since the shape of the raw material is maintained, in many cases, the shape of the raw material to be used can be selected so that the shape of the product is arbitrary. It has the advantage that it can be manufactured.

The high performance carbon material of the present invention thus obtained has a specific surface area of 1800 to 2800 m ² / g, a total pore volume of 1.3 to 2.0 ml / g, and an average pore radius of 11 to 15Å.
It has a very high decomposition performance for COD source materials.

The high-performance carbon material of the present invention can be produced by adding a magnesium compound or a silver compound to a carbonaceous material having pores and subjecting it to heat treatment in an oxidizing gas atmosphere. For example, even if a potassium compound is added and the same operation is performed, a high performance carbon material cannot be obtained. From this, the mechanism of formation of the high specific surface area and the ability to decompose the COD source material in the present invention is not clear, but the catalytic performance peculiar to the impregnated metal causes an oxidation reaction between carbon and an oxidizing gas to cause selective gasification. It is presumed that micropores are accelerated to form a high specific surface area, and at the same time, active sites for decomposing the COD source substance are generated.

COD using the high performance carbon material of the present invention
The decomposition of the source material is, for example, decomposition of hydrogen peroxide in waste water. Decomposition of hydrogen peroxide is generally carried out by bringing an aqueous solution containing hydrogen peroxide, an organic solvent containing hydrogen peroxide or an acid and base solution containing hydrogen peroxide into contact with the carbon material of the present invention. The method is not limited to such a method, and it can be decomposed even in the state of mist or vapor of hydrogen peroxide.

When decomposing hydrogen peroxide in the liquid to be treated using the high performance carbon material of the present invention, the pH of the liquid to be treated is
The concentration of hydrogen peroxide in the liquid to be treated is not particularly limited, and it can be used in a wide range of liquid properties. Decomposition of hydrogen peroxide using the high performance carbon material of the present invention is carried out in a batch system,
It can be carried out by any of the continuous methods, and the treatment temperature, treatment time and the like can be appropriately selected depending on the type of the liquid to be treated.

The high-performance carbon material of the present invention shows high activity for decomposing other pollutants such as hydrazine, and has a decomposing performance several tens of times that of commercially available activated carbon. Decomposition of other organic substances also shows high decomposition activity in the presence of an oxygen generator, and is effective in reducing COD in wastewater. Also, a coloring component, C
Adsorption and removal of OD source components, decomposition of ozone and NO _x ,
Use for adsorption and removal of harmful substances such as SO ₂ , CO and CO ₂ , adsorption and recovery of dissolved metals, occlusion of methane, canister for adsorbing gasoline, electric double layer type capacitor, electrode of battery, and medicine You can

[0033]

EXAMPLES Next, the method of the present invention will be described more specifically by way of examples. For the physical properties of each carbon material, the adsorption isotherm obtained by the N ₂ gas adsorption method was determined, and the BET specific surface area was P / P _O
= BET plot in the range of 0.02-0.3 (multipoint method)
Sought by. (Otoso manufactured by Yuasa Ionics
Micropores are pores having a diameter of 20 Å or less, and mesopores are pores having a diameter of 20 to 500 Å. C
As a test example of the OD source substance decomposition performance, the resolution of hydrogen peroxide was measured.

Example 1 A beaker having a volume of 500 ml was charged with 10 g of commercially available activated carbon having a size of 12 to 32 mesh and ion-exchanged water 250.
After adding ml, the mixture was boiled for 30 minutes with stirring. To this, 0.8 g of magnesium chloride powder (0.08 by weight ratio to the raw carbonaceous material) was added, mixed and dissolved, then allowed to cool and left to stand for 24 hours. Then, the mixture is filtered,
Filter the activated carbonaceous material with 200 ml of deionized water to
After washing twice, it was dried in a vacuum dryer at 110 ° C. for 2 hours. 2 g of this product was charged into a reaction tube, heated in a carbon dioxide stream from room temperature to 1000 ° C. at a temperature rising rate of 25 ° C./min, and held at the same temperature for 90 minutes for activation to obtain a high-performance carbon material. . Using the obtained high-performance carbon material of 555 ppm, a hydrogen peroxide decomposition test was carried out by stirring a 4000 ppm hydrogen peroxide solution (pH 2) at room temperature for 15 minutes. Table 1 shows the results of measurement of various physical properties and decomposition rate of hydrogen peroxide.

Example 2 A high performance carbon material was obtained in the same manner as in Example 1 except that magnesium carbonate was added instead of magnesium chloride. Table 1 shows the results of the physical properties of the obtained high performance carbon material and the decomposition rate of hydrogen peroxide.

Example 3 A high performance carbon material was obtained in the same manner as in Example 1 except that magnesium sulfate was added instead of magnesium chloride. Table 1 shows the results of the physical properties of the obtained high performance carbon material and the decomposition rate of hydrogen peroxide.

Example 4 A high performance carbon material was obtained in the same manner as in Example 1 except that magnesium nitrate hexahydrate was added instead of magnesium chloride. Table 1 shows the results of the physical properties of the obtained high performance carbon material and the decomposition rate of hydrogen peroxide.

Example 5 A high performance carbon material was obtained in the same manner as in Example 1 except that magnesium acetate was added instead of magnesium chloride. Table 1 shows the results of the physical properties of the obtained high performance carbon material and the decomposition rate of hydrogen peroxide.

[Table 1]

From Table 1, addition of each magnesium compound is effective in increasing the specific surface area and COD.
It is clear that the source material has high decomposition activity and excellent performance.

Example 6 0.01 g of magnesium nitrate hexahydrate,
A high performance carbon material was obtained in the same manner as in Example 1 except that 0.1 g, 2.5 g and 5.0 g were added. Table 2 shows the results of the physical properties of the obtained high-performance carbon material and the decomposition rate of hydrogen peroxide.

[0041]

[Table 2]

Example 7 A high performance carbon material was obtained in the same manner as in Example 1 except that 0.01, 0.1, 0.5 and 1.0 of silver nitrate were added. The results of the physical properties of the obtained high performance carbon material and the decomposition rate of hydrogen peroxide are shown in Table-3.

Example 8 A high performance carbon material was obtained in the same manner as in Example 1 except that 0.5 g of silver acetate was added. The results of the physical properties of the obtained high performance carbon material and the decomposition rate of hydrogen peroxide are shown in Table-3.

[0044]

[Table 3]

Comparative Example 1 Using coconut husk charcoal (specific surface area 84 m ² / g) as a carbonaceous material, a heat treatment was carried out in the same manner as in Example 1 to obtain a carbon material. The results of the physical properties of the obtained carbon material and the decomposition rate of hydrogen peroxide are shown below.

[0046]

[Table 4]

Comparative Example 2 A carbon material was obtained in the same manner as in Example 1 except that no metal compound was added and 500 ppm of magnesium nitrate hexahydrate was added. The results of the physical properties of the obtained carbon material and the decomposition rate of hydrogen peroxide are shown.

[0048]

[Table 5]

Comparative Example 3 A carbon material was obtained in the same manner as in Example 1 except that 3 g of potassium nitrate was added instead of magnesium chloride. The results of the physical properties of the obtained carbon material and the decomposition rate of hydrogen peroxide are shown.

[0050]

[Table 6]

[0051]

The method of the present invention has a high specific surface area,
Moreover, a high-performance carbon material having a high activity of decomposing a COD source substance can be obtained. In addition, the amount of metal compounds such as magnesium and silver compounds used is extremely small, there is no corrosiveness of the equipment and there is no clogging due to the mixture, the manufacturing operation is simple, the continuation is easy, and the manufacturing is economical and industrially advantageous. .

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[Procedure amendment]

[Submission date] August 16, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high-performance carbon material having a high resolving power for a COD source material and a high specific surface area. Carbon material of the present invention has a high resolution for COD source material, such as hydrogen peroxide, arsenic
Since it has extremely excellent decomposition activity against inorganic substances such as dorazine and organic substances, it is useful as a decomposition catalyst for these COD source substances.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

For example, when a waste liquid containing an inorganic substance such as hydrogen peroxide or hydrazine or an organic substance is discharged as it is, not only the COD is increased but also when the waste liquid is mixed with a biological activated sludge treatment device, hydrogen peroxide In the case of contained wastewater, oxygen gas generated by decomposition causes suspension to float, causing various troubles such as deterioration of water quality of treated water. Therefore, it is necessary to decompose and discharge these waste liquids in advance, and there is a method of utilizing activated carbon as the decomposition method.

Claims (3)

[Claims] 1. A high-performance carbon material characterized by adding a magnesium compound or a silver compound to a carbonaceous material having pores and having a specific surface area of 100 m ² / g or more and then heat-treating it in an oxidizing gas atmosphere. Manufacturing method. 2. The method for producing a high performance carbon material according to claim 1, wherein the magnesium compound is added to the carbonaceous material in a weight ratio of 1: 0.001 to 1: 0.5. 3. The method for producing a high performance carbon material according to claim 1, wherein the silver compound is added to the carbonaceous material in a weight ratio of 1: 0.001 to 1: 0.1.