JPH05253478A - Adsorptive body and its production - Google Patents

Abstract

PURPOSE:To decrease pressure drop, to enhance adsorption power and to give sterilization action in an adsorbent. CONSTITUTION:Adsorptive bodies 1a, 1b consist of sheet absorbents 2a, 2b made of a sintered body of active carbon and carbonaceous electrodes 3a, 3b integrated with the adsorbents. A flow passage is formed by a spacer 5 and a groove 6 between the absorbents 2a, 2b. The adsorptive bodies 1a, 1b are obtained by molding and sintering the carbonaceous electrode such as carbon fiber yarn with a mixed material in a process to thermal-press mold the mixed material of active carbon such as an active carbon fiber with a sinterable binder in fibrous state or the like. The adsorbent constituted of the sintered sheet has 0.4-1.0g/cm<2> density and 0.05-5mm thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorbent which can be sterilized electrochemically and has a high adsorbability, and a method for producing the adsorbent.

[0002]

As a water purifier having an electrochemical sterilization effect, the applicant of the present application has disclosed in Japanese Utility Model Laid-Open No. 26394/1990 that an electrode is a water-permeable adsorbent containing activated carbon fibers. The formed electrochemical sterilizer was proposed. In this device, by applying a voltage, in the process of passing clean water through the water-permeable adsorbent, it is possible to sterilize microorganisms such as Escherichia coli in clean water, and by the water-permeable adsorbent,
Can absorb chlorine components and remove them.

However, as the adsorbent, other fiber materials and binders such as heat-melting resins are used, for example, 2
Contains 5% or more, the packing density of activated carbon fiber is 0.1g
/ Cm ³ or less, low. In addition, the heat-meltable binder closes the pores of the activated carbon and reduces the amount of pores effective for adsorption. Therefore, the amount of adsorption per unit volume is small. In addition, since it contains other fiber materials and binders, the electric resistance is increased. Furthermore, the water flow resistance of clean water passing through the adsorbent is large. Therefore, the pressure loss increases and smooth processing is impaired.

It is also possible to attach a metal electrode to a water-permeable adsorbent containing activated carbon fibers or activated carbon. However, in this case, a potential difference is generated between the carbon and the metal, and the metal electrode is corroded. Therefore, the bactericidal effect cannot be maintained for a long period of time.

Therefore, an object of the present invention is to provide an adsorbent which has not only a small pressure loss but also a large adsorption amount per unit volume and a bactericidal action.

Another object of the present invention is to provide a method for producing an adsorbent having the above-mentioned excellent properties.

[0007]

As a result of earnest studies, the present inventors have found that an adsorbent obtained by compression-molding and firing at least activated carbon is excellent in electric conductivity and adsorption capacity, and that it is composed of a sintered body. The present invention has been completed by finding that the pressure loss is significantly reduced by forming the flow path between the materials.

That is, the present invention provides an adsorbent composed of an adsorbent made of a sintered body of activated carbon and a carbonaceous electrode integrated with the adsorbent.

The density of the adsorbent is 0.4
˜1.0 g / cm ³ is preferable, and the adsorbent is preferably composed of a sintered sheet having a thickness of 0.05 to 5 mm. Further, the activated carbon includes activated carbon fibers,
The carbonaceous electrode preferably comprises carbon fibers.

The present invention is a method comprising at least a molding step of pressure-molding activated carbon and a sintering step of firing the obtained molded article, wherein in the molding step, a part of the carbonaceous electrode is activated carbon. Provided is a method for manufacturing an adsorbent that is molded together.

In this method, a method including a molding step of molding a slurry containing activated carbon fibers and a binder by a suction molding method or a papermaking method, wherein the suction molding method together with a part of the carbon fiber yarn is carried out in the molding step. Alternatively, it is preferable to perform molding by a papermaking method, pressurize the molded adsorbent, and bake.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings, if necessary.

FIG. 1 is an exploded perspective view showing an adsorbent which is an embodiment of the present invention.

The adsorbents 1a and 1b are sheet-like adsorbents 2a and 2b made of a sintered sheet of activated carbon fiber, and are integrated with these adsorbents, respectively, and extend outward from the end faces of the adsorbents 2a and 2b. It is composed of carbonaceous electrodes 3a and 3b. In this example, a pair of adsorbents 1 facing each other
a and 1b are used.

Since the adsorbents 2a and 2b are made of a sintered sheet of activated carbon fiber, they are substantially carbonaceous adsorbents and have a characteristic that almost no binder is present. The carbonaceous electrodes 3a and 3b are composed of yarns of carbon fibers, and are entangled with activated carbon fibers or the like by being loosened by the carbon filaments 4a and 4b inside the adsorbents 2a and 2b. Therefore, the adsorbents 2a and 2b and the carbonaceous electrode 3
The bonding strength with a and 3b is extremely high.

Further, the lattice-shaped spacers 5 are formed on the surface of the one adsorbent 2a, and the surface of the other adsorbent 2b is formed.
Lattice-shaped grooves 6 are formed at positions different from the spacers 5. Therefore, the spacer 5 can arrange the pair of adsorbents 2a and 2b in a non-contact state, and a labyrinth-like flow path is formed between the adsorbents 2a and 2b.

Such an adsorbent 1 is provided with a supply port to which a fluid to be treated such as gas or liquid is supplied, and the adsorbents 2a, 2a.
It is disposed in a casing (not shown) having a discharge port through which the fluid processed by b is discharged.

When such adsorbents 1a and 1b are used,
The fluid to be processed is sterilized and adsorbed in the process of flowing through the flow path between the adsorbents 2a and 2b. That is, when a voltage is applied to the carbonaceous electrodes 3a and 3b, an electric field is formed between the adsorbents 2a and 2b, so that microorganisms such as Escherichia coli contained in the fluid to be treated and microorganisms adhering to the adsorbents 2a and 2b are included. Can be sterilized. In particular, the adsorbents 2a and 2b
Has high electrical conductivity because it is a sintered carbonaceous material. Further, the carbonaceous electrodes 3a and 3b having excellent chemical resistance and corrosion resistance are formed integrally with the adsorbents 2a and 2b and intertwined with the activated carbon fiber. Therefore, the bonding strength between the adsorbents 2a and 2b and the carbonaceous electrodes 3a and 3b is high, and the sterilization effect can be maintained for a long period of time.

The components to be adsorbed in the fluid to be treated are removed by the adsorbents 2a and 2b. Especially adsorbent 2
Since a and 2b are carbonaceous materials made of a sintered sheet, a high adsorption performance of activated carbon fiber can be secured. Furthermore, since the fluid to be processed mainly flows through the flow path, the pressure loss is small. The adsorbed component in the fluid to be processed permeates and diffuses into the adsorbents 2a and 2b in the process of flowing through the flow path, and is efficiently adsorbed. Therefore, the adsorbents 1a and 1b have both high adsorption capacity and low pressure loss.

Further, since the adsorbents 2a and 2b are made of carbonaceous material, the mechanical strength and shape retention are great, and the operation of exchanging the adsorbents 1a and 1b is easy.

The activated carbon contained in the adsorbent may be in any form such as fiber or powder. In particular, when activated carbon fibers are used, a high-strength sintered body can be obtained with a small amount of binder based on structural characteristics such as entanglement of fibers and high strength in the fiber orientation direction. As the activated carbon fiber, generally, activated carbon having a fiber diameter of about 2 to 30 μm, a fiber length of about 0.1 to 10 mm and fine pores of a pore size of about 8 to 20 Å and a specific surface area of about 500 to 2500 m ² / g is used. Preferably. As the granular activated carbon, fine activated carbon having an average particle diameter of about 10 to 100 μm and a specific surface area of 500 m ² / g or more is preferable from the viewpoint of adsorption and desorption characteristics.

The origin of activated carbon is not particularly limited.
It may be any of coal-based, petroleum-based, phenolic resin-based, polyacrylonitrile-based, cellulose-based, coconut husk-based, wood-based, and the like.

The sintered body of activated carbon is 100 parts by weight of activated carbon and, if necessary, 20 parts by weight or less, preferably 2 to 20 parts by weight.
It is manufactured by adding about 1 part by weight of a binder, mixing, shaping, and sintering. It is not necessary to use a binder if a sintered body having sufficient strength can be obtained even if the activated carbon alone is sintered.

When a binder is used, a sinterable binder which is integrated with activated carbon by a sintering operation is particularly suitable. Examples of the sinterable binder include infusible carbon made of unfired carbon obtained by infusibilizing raw material pitch; thermosetting resin such as aramid resin, phenol resin, epoxy resin, urea resin; infusible acrylic resin, An infusible heat-fusible resin such as a melted polyvinyl alcohol resin is exemplified. Among these sinterable binders, a binder that can be carbonized is preferable. Unlike the heat-meltable binder, these sinterable binders are characterized in that the ratio of blocking the pores of the activated carbon is extremely low. Further, when the sinterable binder is used in a fibrous form (for example, when using unfired carbon fiber which is obtained by spinning raw material pitch and infusibilized), the ratio of plugging pores of activated carbon Will be less. As the fibrous sinterable binder, a yarn diameter of about 5 to 100 μm and a length of 0.1 to 5 mm
It is preferable to use a grade.

The activated carbon or the blend of the activated carbon and the binder may be added, if necessary, to 100 parts by weight of the activated carbon.
Up to about 50 parts by weight of reinforcing material may be further added. Examples of such a reinforcing material include natural fibers such as hemp and paper pulp, and heat-meltable fibers such as polyethylene yarn and polypropylene yarn.

The binder and the reinforcing material are likely to be carbonized and / or gasified in the sintering step described later.

The adsorbent need not have a flat plate shape or a sheet shape as shown in the drawing, but may have a curved shape, a hollow cylindrical shape, a hollow polygonal shape or the like as long as it is a sintered body containing activated carbon. ..

The density of the adsorbent may be within the range that does not impair the characteristics such as adsorption capacity and strength, but at least the density of the portion integrated with the carbonaceous electrode enhances the bonding strength.
0.4 g / cm ³ or more, especially 0.4 to 1.0 g / cm ³
Is preferred. The average density of the adsorbent is, for example,
0.4 g / cm ³ or more, preferably 0.4 to 1.0 g /
It is about cm ³ . Such a high-density adsorbent has not only high strength, but also is excellent in adsorbability because it is mostly composed of activated carbon. The density of the adsorbent on the side in contact with the fluid to be treated is 0.4 g / cm ³ or less, for example, 0.1 to 0.4 in order to promote permeation and diffusion of the fluid to be treated.
It may be about g / cm ³ .

The thickness of the sheet-shaped adsorbent formed of a sintered sheet is, for example, 0.05 to 5 mm, preferably 0.2 to 1
It is about mm. When the thickness of the adsorbent exceeds 5 mm, the adsorbent has a high density, and thus the activated carbon present inside may not be effectively utilized during the fluid adsorption process.

The type of carbonaceous electrode is not particularly limited, and may be, for example, a long piece of graphite film, but it is preferable to include carbon fiber in order to enhance the integrity with the adsorbent. .. Electrodes containing carbon fibers include, for example, carbon fiber yarns, cloths, knits, and the like. Preferred electrodes are those that are flexible and do not break during molding, such as carbon fiber yarns.

In the illustrated example, the carbon fibers are loosened into filaments and entangled with the activated carbon fibers of the adsorbent to be integrated, but in order to enhance the integrity with the adsorbent, an electrode containing carbon fibers is used. May be meandering or curved inside or on the surface of the adsorbent. When the activated carbon of the adsorbent contains activated carbon fibers, the carbonaceous electrode advantageously contains carbon fibers capable of increasing the degree of entanglement of the fibers.
When a sinterable binder is used, since the adsorbent and the electrode are integrated in the sintering step described later, the carbonaceous electrode may be bonded on the surface of the adsorbent.

A flow path for the fluid to be treated may be formed between the pair of adsorbents. The channel can be formed in various ways. For example, a concavo-convex portion may be formed on the opposing surfaces of both adsorbents. Further, the flow path may be formed by disposing the adsorbents at intervals. The adsorbent is not limited to a pair of adsorbents, and may be composed of a plurality of pairs of adsorbents.

The interval between the adsorbents made of a sintered body can be appropriately selected depending on the usage conditions of the adsorbents. Considering the pressure loss and the length of the adsorbent, the space between the adsorbents is
It is preferably about 0.05 to 10 mm. When the distance between the adsorbents is less than 0.05 mm, the pressure loss becomes large, and when it exceeds 10 mm, the substance to be adsorbed easily breaks through.

The adsorbent of the present invention can be produced by at least a forming step of forming activated carbon and a sintering step of firing the obtained formed product.

In the molding step, not only activated carbon alone but also a mixture of activated carbon and a sinterable binder or a mixture further containing a reinforcing material can be used. Preferably a mixture containing activated carbon and a sinterable binder is used.

In the molding step, a part of the carbonaceous electrode is placed in a mold together with the activated carbon and the mixture, and at least pressure-molded. At the time of molding, it is preferable to perform heating and pressure molding. In this molding step, therefore, the activated carbon and the carbonaceous electrode are compressed and integrated in the molded product. In the forming step, if the end portions of the carbon fiber yarn are loosened into filaments or the carbonaceous electrode is meandered or bent to be placed in the forming die as described above, the integrity of the activated carbon and the carbonaceous electrode is further enhanced.

The molding is performed according to the density of the adsorbent, for example,
Pressure of about 5 to 1000 kgf / cm ² , preferably 1
It can be performed at about 00 to 800 kgf / cm ² . If the pressurizing pressure is less than 5 kgf / cm ² , the adsorbent has a low strength and a low density, and is likely to be 1000 kg.
If it exceeds f / cm ² , the pores of the activated carbon may be destroyed and the adsorption performance of the adsorbent may deteriorate.

When fibrous activated carbon is used, a low-density preform may be prepared in advance by a dry method or a wet method and then sintered.

In the case of the wet method, activated carbon alone, a mixture of activated carbon and a sinterable binder, or a mixture containing a reinforcing material is dispersed in water and mechanically stirred to prepare a uniform aqueous slurry. Then, the aqueous slurry is put into a mold having a suction port and sucked to obtain a preform. At the time of this suction molding, a part of the carbonaceous electrode is placed in a mold and suction molded together with activated carbon and the like. The preform can also be obtained by a papermaking method in which paper is made together with a part of the carbonaceous electrode. After drying the obtained preform, it is put into a mold, shaped, and subjected to a sintering step. In the case of the dry method, a preformed body in the form of a non-woven fabric or the like may be put in a mold in advance by the dry method and sintered under the same conditions as above. A part of the carbonaceous electrode may be mechanically entangled and joined with the preform by a dry method and then subjected to the forming step and the sintering step. You may.

When using these preforms,
It is easy to handle and uneven density can be prevented. In particular, when a preformed body produced by a wet method is used, the uneven density of the basis weight is small, and the uneven density of the sintered body is also small.

As is clear from the above, in the molding step, in the step of suction molding a slurry containing activated carbon fibers and a binder using a suction molding die,
It is preferable to dispose the carbon fiber yarn in the suction mold and perform the suction molding. Further, it is also preferable to paper-form the slurry together with a part of the carbon fiber yarn by a paper-making method.

The molded product obtained in the molding step has a temperature of, for example, about 500 to 1500 ° C., preferably 800 to 13
It is subjected to a sintering process in which it is sintered under the condition of about 00 ° C. If the sintering temperature is less than 500 ° C., the sintering will be insufficient, and the strength will be low, and the adsorbent will have a low density. If the sintering temperature exceeds 1500 ° C., the pores of the activated carbon are likely to be clogged with the sinterable binder, and the adsorbability of the adsorbent tends to decrease. By the sintering, the adsorbent and the carbonaceous electrode are firmly integrated. Further, when the molded product contains a sinterable binder, the bonding strength between the adsorbent and the carbonaceous electrode can be further increased. Along with the sintering, the binder and the reinforcing material are carbonized and / or gasified. Therefore, the obtained adsorbent has high density and high mechanical strength,
High content of activated carbon. Further, since the adsorbent is carbonaceous, it has high heat resistance and chemical resistance, and also has excellent electrical conductivity. Furthermore, since the compression molded product is sintered,
The dimensional accuracy of the obtained adsorbent is also high.

Sintering can be carried out in an inert atmosphere such as nitrogen gas, helium gas or argon gas or under vacuum. The sintering time can be appropriately selected depending on the type of activated carbon used, the shape of the molded body, the type and amount of the sinterable binder, and the like, but is usually about 5 seconds to 30 minutes.

[0044]

According to the adsorbent of the present invention, the following effects are produced.

(1) Since the adsorbent is formed of a high density sintered body, it is possible to remarkably prevent the pores of the activated carbon from being blocked, and the electric conductivity is high. Therefore, the adsorbent in which the adsorbent and the carbonaceous electrode are integrated has a high adsorption performance and exhibits a high sterilization effect by applying a voltage to the electrode.

(2) If a flow path is formed between a plurality of adsorbents to form an adsorbent, the fluid to be processed can be processed with a low pressure loss.

(3) Since the bonding strength between the adsorbent and the carbonaceous electrode is large, the adsorption treatment and the sterilization treatment can be smoothly performed for a long period of time.

(4) The adsorbent formed of a sintered body has excellent mechanical strength, heat resistance and chemical resistance. Therefore, the adsorbent has excellent handleability and high adsorbability even under severe conditions.

According to the method of the present invention, since the molding step and the sintering step are included, it is possible to manufacture an adsorbent having the above-mentioned excellent characteristics and high dimensional accuracy.

[0050]

EXAMPLES The present invention will be described in more detail based on the following examples.

EXAMPLE Pitch-based activated carbon fiber having a specific surface area of 1500 m ² / g [98 parts by weight of A-15, manufactured by Adol Co., Ltd.] and 2 parts by weight of an acrylic resin binder as a binder were dispersed in water to prepare a carbon fiber. Beating was performed until the length became almost all 5 mm or less to obtain a uniform slurry.

Next, a part of the carbon fiber yarn was placed in a flat mold having a large number of suction ports at the bottom, the above slurry was put therein, and the mixture was sucked and wet-molded into a flat plate having a basis weight of about 360 g / m ^2. A sheet (100 mm x 100 mm) was obtained. By holding the wet-molded sheet at a pressure of 50 kg / cm ² and a temperature of 930 ° C. for 20 seconds, a flat plate-like adsorbent having a thickness of 0.5 mm and a bulk density of 0.6 g / cm ³ as shown in FIG. Got

In the same manner, a plate-shaped adsorbent having grooves as shown in FIG. 1b was obtained by using a mold having a grid-like projection and a plate-shaped mold. Distance between grooves is 5m
m, and the depth of the groove was about 0.1 mm. A spacer having a thickness of about 0.1 mm was attached to the flat plate-shaped adsorbent as shown in FIG.

A pair of adsorbents was obtained from the adsorbents 1a and 1b. The obtained adsorbent was capable of treating the fluid to be treated with a low pressure loss, had a small contact electric resistance between the carbonaceous electrode and the adsorbent, and had a large bonding strength.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an adsorbent according to an embodiment of the present invention.

[Explanation of symbols]

 1a, 1b ... Adsorbent 2a, 2b ... Adsorbent 3a, 3b ... Carbonaceous electrode 4a, 4b ... Carbon filament 5 ... Spacer 6 ... Groove

Claims (6)

[Claims] 1. An adsorbent comprising an adsorbent made of a sintered body of activated carbon and a carbonaceous electrode integrated with the adsorbent. 2. The density of the adsorbent is 0.4 to 1.0 g / c.
The adsorbent according to claim 1, which is m ³ . 3. The adsorbent according to claim 1, wherein the adsorbent is composed of a sintered sheet having a thickness of 0.05 to 5 mm. 4. The adsorbent according to claim 1, wherein the activated carbon contains activated carbon fibers and the carbonaceous electrode contains carbon fibers. 5. A method comprising at least a molding step of pressure-molding activated carbon and a sintering step of firing the obtained molded article, wherein a part of the carbonaceous electrode is molded together with the activated carbon in the molding step. A method for producing an adsorbent. 6. A method including a molding step of molding a slurry containing activated carbon fibers and a binder by a suction molding method or a papermaking method, wherein in the molding step, a suction molding method or a papermaking method together with a part of the carbon fiber yarn. The method for producing an adsorbent according to claim 5, wherein the adsorbent is molded by a method and the molded adsorbent is pressurized and fired.