JPH07116510A - Adsorbent and porous adsorbing material - Google Patents

Abstract

PURPOSE:To enhance the adsorptivity of a gas to be adsorbed per volume, to facilitate the handling, to improve the workability and to miniaturize a housing body by making an adsorbent by forming a finely pulverized body of an activated carbon fiber into granules. CONSTITUTION:A cotton like activated carbon fiber(ACF) is supplied into a mixer with water so as to be 1:100 in the weight ratio of ACF to water and is wet-pulverized for about 3min. As a result, an ACF short fiber as a coarse particle is obtained and next, the finely pulverized body of ACF is obtained by finely pulverizing the ACF short fiber with, for instance, a ball mill, dehydrating and drying. The finely pulverized body is about 1200m<2>/g in specific surface area and about 0.1mm in length in the fiber direction of the finely pulverized body. Next, a binder and water are added to the finely pulverized body and kneaded with, e.g. mortar to obtain a slurry. Next, the adsorbent is obtained by forming the slurry into the granules having 1-2mm in particle diameter with a granulator and drying at about 120 deg.C for 3 hours.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile air cleaner,
The present invention relates to an adsorbent and a porous adsorbent that are used for various purposes such as an indoor air purifier or a fuel vapor treatment device.

[0002]

2. Description of the Related Art In recent years, the adverse effect of fuel air generated from a fuel tank of an internal combustion engine on the environment and the human body has become a problem. Therefore, there is a move to tighten steam emission regulations. In addition, the need for deodorization is increasing as the desire for indoor comfort increases. In this way, as various environmental improvement intentions increase, an adsorbent that adsorbs fuel vapor, odor, etc. is required. In response to such a demand, conventionally, for example, a method of forming various deodorants such as activated carbon and a catalyst into a sheet shape or a honeycomb shape, or a porous fiber aggregate such as a web or a tow containing activated carbon fibers as a main material is used. There is a method used (Japanese Patent Publication No. 59-24271).

[0003]

[Problems to be Solved] However, the former method using activated carbon has a problem that the adsorption rate is relatively slow and the rapid effect is weak. Further, the latter method using the fiber assembly has a fast effect because the adsorption rate is relatively high. However, since the packing density of activated carbon fiber is low, it is difficult to improve the adsorption effect per volume more than powdered activated carbon.

Further, when porous activated carbon fibers are used, the pressure loss becomes high because the open spaces between the fibers are very small. Also, during repeated use over a long period of time, purging air does not easily flow due to clogging, etc., and it becomes difficult to separate it.
Therefore, there is a problem that the reproduction efficiency is deteriorated. In view of such conventional problems, the present invention aims to provide an adsorbent and a porous adsorbent having excellent adsorption performance and regeneration performance.

[0005]

The present invention is an adsorbent characterized in that a finely pulverized body of activated carbon fibers is formed into a granular shape.

In the present invention, the finely pulverized body of activated carbon fibers has many fine pores. The specific surface area of the finely pulverized body is not particularly limited, but it is preferably 700 to 2000 m ² / g. If it is less than 700 m ² / g, the amount of adsorption may be insufficient. On the other hand, 2000m ² / g
If it exceeds, the pore volume becomes large, the packing density is difficult to increase, and the efficiency is extremely inferior in terms of manufacturing as well, which may make it difficult to obtain. Here, the specific surface area means a surface area including pores per unit weight of the finely pulverized body. The length of the finely pulverized material in the fiber direction is 0.0
It is preferably 5 to 0.5 mm. If it is less than 0.05 mm, it may be too fine and difficult to handle. On the other hand, when it exceeds 0.5 mm, the adsorption performance per volume of the finely pulverized body may be deteriorated.

The activated carbon fiber may have a proper pore size and specific surface area depending on the gas to be adsorbed.
Several kinds of activated carbon fibers having different characteristics may be used in combination for the composite adsorbed gas. Particularly when a gas to be adsorbed having a large molecule is contained, it is effective to combine powdered activated carbon having a large pore size with the finely pulverized body.

An example of a method for producing the above adsorbent will be described. First, the activated carbon fiber is roughly pulverized with a mixer to obtain coarse particles. Next, the coarse particles are pulverized into a granular shape by a ball mill or the like to prepare a finely pulverized body of activated carbon fibers. Then, a binder, water and the like are added to this finely pulverized body and kneaded. Then, this is formed into a granule by a granulator to obtain the adsorbent. As the binder, it is preferable to use a resin having a small film-forming property, such as hydrogenated rosin, corn starch, or methyl cellulose, in order to contribute to the adsorption performance even in the central portion of the granules.

In the adsorbent of the present invention, it is preferable that either one or both of an acidic gas adsorbate and a basic gas adsorbate be attached to the finely pulverized body of activated carbon fibers. As a result, low pressure loss, acidity, basicity,
It has a fast adsorption speed for the neutral gas to be adsorbed and realizes one-pass deodorizing performance that is unmatched, that is, one-pass odorless. The method of impregnation includes, for example, wet-mixing the coarse particles of the activated carbon fiber in a solution of one or both of the acidic gas adsorbate and the basic gas adsorbate, and finely pulverizing the coarse particles. There is a method of simultaneously impregnating the organic substance.

The acidic gas adsorbate is an organic compound having an amino group, and includes 3-aminopropyltrihydrosilane, γ-aminopropylethoxysilane, dimethyltrimethylsilylamine, and N- (2-aminoethyl).
—One or two or more compounds selected from the group of 3-aminopropyltrimethoxysilane. The acid gas adsorbate is capable of adsorbing acid gas such as hydrogen sulfide and acetaldehyde.

The basic gas adsorbate is an organic compound having a carboxyl group and is selected from the group consisting of L-tartaric acid, cobalt oxide, manganese oxide, acetylacetone cobalt, acetylacetone manganese, malic acid, and succinic acid. Two or more compounds and the like. The basic gas adsorbate is capable of adsorbing an alkaline gas such as ammonia. The adsorbent may be formed into a sheet shape or a honeycomb shape before use.

A porous adsorbent can be constructed by supporting the adsorbent on a porous body. The porous body has a three-dimensional network structure, and for example, urethane foam, honeycomb, or the like is used. This porous adsorbent has a higher adsorption rate than conventional activated carbon. The porous adsorbent has a three-dimensional mesh structure. Therefore, when the gas is passed through the inside, there is a low pressure loss and the contact efficiency with the adsorbed gas is good. Therefore, it has an excellent one-pass adsorption effect. In addition, the porous adsorbent has a good adsorption performance for odorous components such as hydrogen sulfide, acetaldehyde, ammonia, etc., and can function as an excellent deodorant.

As a method for supporting the adsorbent on the porous body, there is a general method such as impregnating the porous body in a viscous slurry finely pulverized body and drying the porous body. After impregnation, it is preferable that the porous body is used as a continuous ventilation hole and dried. As a result, an adsorbent having a three-dimensional network structure is obtained. Further, as another effective filling method, there is a method of coating the finely pulverized body on the surface of the granular activated carbon.

Further, when the entire amount of the above-mentioned adsorbent is carried on the porous body, the absorption and desorption speeds are remarkably faster than the conventional granular activated carbon. As a result, almost all of the deodorant is used for adsorption, resulting in the best performance. Further, the adsorbent may be combined with granular activated carbon and supported on the porous body. Even in this case, since the finely pulverized body of activated carbon fibers is present, the adsorption performance is improved.

[0015]

FUNCTION AND EFFECT In the adsorbent of the present invention, a finely pulverized body of activated carbon fiber is granulated and used. Therefore, it is possible to highly densely fill the storage body such as the adsorption tank. Therefore, the adsorption performance of the adsorbed gas per volume is high. In addition, when filling the container, it is not necessary to press the activated carbon fiber as it is. Therefore, it is easy to handle and the workability is improved. Also,
It is possible to reduce the size of the storage body. In addition, since a finely pulverized body of activated carbon fiber is used, the fluid flow is good. Therefore, the adsorbent of the present invention has a low pressure loss during use. Therefore, it can be used repeatedly over a long period of time and has excellent playback performance.

Further, the activated carbon fiber has many fine pores which the granular activated carbon does not have. Therefore, it is possible to sufficiently adsorb the low-concentration, small-molecule adsorbed gas that is difficult to be adsorbed by the granular activated carbon. Therefore, the adsorbent of the present invention can adsorb adsorbed gases such as evaporated fuel, odorous components, and harmful gases.

Furthermore, the adsorbent of the present invention can be expected to have a ripple effect in various applications. For example, the adsorbent can be used in a gasoline internal combustion engine, a diesel internal combustion engine, an evaporated fuel processing device mounted on a fuel tank, an automobile or indoor air purifier, a water purifier, a solvent recovery device, and the like. As described above, according to the present invention, it is possible to provide an adsorbent and a porous adsorbent having excellent adsorption performance and regeneration performance.

[0018]

【Example】

Example 1 An adsorbent according to an example of the present invention will be described with reference to FIGS. The adsorbent of this example is formed by finely pulverizing activated carbon fibers (hereinafter referred to as ACF) into a granular shape, and is filled in the tank 3 of the evaporated fuel processing device 2 shown in FIG. Hereinafter, a method for manufacturing the adsorbent will be described in detail with reference to FIG.

That is, first, cotton-like ACF and water are put into a mixer, and the weight ratio of ACF and water is set to 1: 100.
The ACF was wet milled for 3 minutes. As a result, ACF short fibers (fiber length of 5 mm or less) as coarse particles were obtained. Next, the ACF short fibers are finely pulverized with a ball mill, dehydrated and dried. As a result, a finely pulverized body of ACF was obtained.
The specific surface area of the finely pulverized body is 1200 m ² / g, and the length of the finely pulverized body in the fiber direction is 0.1 mm.

Next, a binder and water were added to the finely pulverized body, and the mixture was kneaded by a smelting machine to obtain a slurry. The binder was added in an amount of 2 parts by weight with respect to 1 part by weight of the finely pulverized body. 5% by weight of water was added to 95% by weight of the binder and the finely pulverized material. Corn starch was used as the binder. Next, this slurry was formed into granules of 1 to 2 mm with a granulator (Erich mixer, pelletizer) and dried at 120 ° C. for 3 hours to obtain an adsorbent.

Next, as shown in FIG. 2, the adsorbent 1 obtained as described above was filled in the tank 3 of the evaporated fuel processing apparatus 2 for the following performance test. In the tank 3,
A fuel tank port 4, an atmosphere port 5, and a purge port 6 are provided. The adsorbent 1 is filled and fixed between the porous rectifying plates 30 and 31 provided in the tank 3. The tank 3 has a volume of 850 cc and a height of 12
cm.

Next, the regeneration performance of this adsorbent was measured. In the measurement, first, from the fuel tank port 4 with the atmosphere port 5 and the purge port 6 closed,
99.9% n-butane as a measuring gas was introduced into the tank 3 containing the adsorbent 1 at a flow rate of 0.5 liter / minute. Then, the measuring gas was adsorbed to the adsorbent 1 up to the 0.3% breakthrough end point (JASOE 501-9).
0 compliant). The weight of the adsorbent at this time was measured and defined as "weight at gas adsorption".

Thereafter, the fuel tank port 4 was closed and the introduction of the measuring gas was stopped. On the other hand, 200 liters of air was introduced from the atmospheric port 5 at a flow rate of 10 liters / minute. At the same time, the purge port 6 was opened, and the atmosphere in the tank 3 and the measurement gas desorbed from the adsorbent 1 were discharged from the purge port 6 for 20 minutes.
The weight of the adsorbent at this time was measured and defined as "weight at the time of gas desorption".

Then, the regeneration performance of the adsorbent 1 was calculated as the working capacity (WC) by the following formula, and the results are shown in Table 1. W. C. = Weight when adsorbing gas (g) -Weight after desorption of gas (g) For comparison, the ACF that has not been subjected to the pulverization treatment
A long fiber (length 1 mm in the fiber direction) was used as Comparative Example 1, and the working capacity of this was also measured in the same manner as above. From the above measurement results, it was confirmed that the working capacity of the adsorbent 1 according to the present invention was improved by about 40% as compared with the granular activated carbon according to the conventional example.

As described above, the packing density can be improved to the same level as that of the granular activated carbon by using the finely pulverized material obtained by granulating ACF as the adsorbent. Therefore, the adsorption performance of the adsorbed gas per volume is high. In addition, the pressure loss during use is low and it can be used repeatedly over a long period of time.

Further, in order to fill the tank with the ACF in the form of cotton, it is necessary to compress it with a press machine or the like, which requires large-scale equipment. However,
In this example, since the finely pulverized body of activated carbon fibers is formed into a granular shape, it is not necessary to press the tank 3 when filling the tank 3. Therefore, it is easy to handle and the workability is improved. Further, the tank can be downsized.

Further, since ACF has many fine pores which are not originally present in granular activated carbon, ACF is excellent in adsorbing an adsorbed gas of low concentration and small molecule. Therefore, it is possible to adsorb many kinds of adsorbed gases. The ACF can maintain the above excellent characteristics even when it is made into a fine powder. Further, by being made into a fine powder, the packing density is improved, and the adsorption / desorption performance is improved correspondingly.

[0028]

[Table 1]

Example 2 In this example, an adsorbent was used as a deodorant. In the above adsorbent, activated carbon fiber (hereinafter referred to as ACF)
Acid gas adsorbate and activated carbon fibers are attached to the finely pulverized product. This adsorbent is filled in a porous body. 3-Aminopropyltrihydrosilane (hereinafter referred to as APTS) is used as the acidic gas adsorbate. L-tartaric acid is used as the basic gas adsorbate. The porous body has a three-dimensional network structure and uses urethane foam.

Next, a method for manufacturing the adsorbent will be described with reference to FIG. That is, first, ACF and water are put into a mixer and wet pulverization of ACF is performed to obtain ACF short fibers (fiber length is 5 mm or less) as coarse particles. At this time, the weight ratio of AFC and water was 1: 100, and the grinding time was 3 minutes. Next, the ACF short fibers were put into a ball mill, and the APTS aqueous solution and the L-tartaric acid aqueous solution were further added. The concentrations of APTS and both aqueous solutions are each 0.1 mol / liter. The weight ratio of ACF short fibers, APTS, and L-tartaric acid was set to 3: 1: 1.

Then, the ball mill is rotated for 10 hours to finely pulverize the ACF short fibers, APTS and L-tartaric acid, and at the same time, APTS and L-tartaric acid are attached to the ACF short fibers respectively, and amino groups and carboxyl groups are added. The group was supported. Next, these were dehydrated and dried at 120 ° C./2 hours. As a result, APTS-impregnated ACF and L-tartaric acid-impregnated ACF were obtained.

Next, the APTS-impregnated ACF and the L-tartaric acid-impregnated ACF were mixed with a binder and water to prepare a slurry for impregnation. As the binder, cornstarch, which has a low coating property, was used. The amount of binder added is
The amount of ACF was adjusted to 5 times the weight of ACF to prepare a 0.5% aqueous solution.

Then, the slurry for impregnation was impregnated with urethane foam having continuous ventilation holes as a porous body. Next, this urethane foam was squeezed to remove excess impregnating slurry and dried at 100 ° C. for 3 hours. Both attachments A
CF had a thickness of about 15 μm and a length of about 25 μm, and was loaded on a urethane foam of 100 g / m ² as a basis weight.

Next, in the adsorbent of the present example, APTS as an acid gas adsorbate and L-tartaric acid as a basic gas adsorbate were impregnated into a finely pulverized body of activated carbon fibers,
APTS-impregnated ACF and L-tartaric acid-impregnated ACF are used. The APTS-impregnated ACF is an adsorbent that chemically adsorbs an acidic gas by a neutralization reaction by the action of an amino group in the component. On the other hand, L-tartaric acid-impregnated ACF is an adsorbent that chemically adsorbs a basic gas by a neutralization reaction by the action of a carboxyl group in the component.

The specific surface area of both impregnated ACFs after the impregnation is about 1000 m ² / g, which is about the same as the specific surface area of the ACF before impregnation is about 1200 m ² / g. Therefore, the neutral gas is trapped in the pores of the porous body and is physically adsorbed. Therefore, by properly combining the APTS-impregnated ACF and the L-tartaric acid-impregnated ACF, it is possible to obtain a multi-deodorant capable of coping with all adsorbed gases of acidic, basic, and neutral. In addition, also in this example, the same effect as that of the first embodiment can be obtained.

Example 3 In this example, the time-dependent change in the gas adsorption rate of the adsorbent of the present invention was measured. For the measurement, the constant temperature and humidity chamber (temperature 25) filled with the initial concentration (R) of the single component gas was used.
The deodorant for measurement was stored at 60 ° C. and 60% humidity for 60 minutes. The grammage of the above deodorant for measurement to be used for measurement is the same (1
00 g / m ² ). During storage, the single component gas in the constant temperature and humidity chamber is constantly circulated. Meanwhile, the residual concentration (Q) of the single component gas remaining in the constant temperature and humidity chamber was measured by a gas chromatograph. A detector tube was used when the single component gas was ammonia.

The removal rate (S) of the single component gas is calculated by the following formula. S (%) = 100 × (R−Q) / R The above-mentioned various single component gases are toluene, hydrogen sulfide, acetaldehyde, and ammonia. The initial concentration (R) of toluene is 1000 ppm. The initial concentration (R) of hydrogen sulfide, acetaldehyde, and ammonia is 100.
It is ppm.

As comparative examples, granular activated carbon (unimpregnated) and ACF sheet (unimpregnated), which are neither impregnated with an acidic gas adsorbate nor a basic gas adsorbate, are used. Example 3 is set. The measurement results are shown in Table 2. From Table 2, it can be seen that the adsorbent of the present invention has significantly superior initial adsorption performance to Comparative Examples 2 and 3, and that the removal rate hardly changes even after 60 minutes.

Next, the pressure loss of the adsorbent of the present invention was measured. As a result, at a wind speed of 30 cm / sec, 3 mmA
It was q (column of water). For comparison, granular activated carbon impregnated with the above APTS and L-tartaric acid was loaded on urethane foam in the same manner as above to obtain a composite sheet. The pressure loss between the adsorbent according to this comparative example and the adsorbent according to the present invention was compared at the same basis weight. As a result, it was confirmed that the product of the present invention had a pressure loss of 1/100 or less compared to the comparative product. Needless to say, the deodorant performance of the present invention is equal to or higher than that of the comparative product.

As described above, since the product of the present invention efficiently contributes to deodorization even inside the layer of the impregnated AFC, it can be used for all adsorbed gases of acidic, basic and neutral even though the pressure loss is low. On the other hand, it has a fast adsorption rate and achieves a unique one-pass deodorizing performance.

[0041]

[Table 2]

Example 4 In the adsorbent of this example, γ-aminopropylethoxysilane, dimethyltrimethylsilylamine and N- (2-aminoethyl) -3- were used instead of the APTS used in the adsorbent of Example 2 above. An acidic gas adsorbate such as aminopropyltrimethoxysilane was used. Further, instead of L-tartaric acid used in the adsorbent of Example 2, basic gas adsorbates such as cobalt oxide, manganese oxide, acetylacetone cobalt, acetylacetone manganese, malic acid, and succinic acid were used.

Others are the same as in the second embodiment. The same measurement as in Example 3 was performed on the adsorbent of this example, and it was confirmed that the same effect as that of the adsorbent according to Example 2 was exhibited.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a method for manufacturing an adsorbent of Example 1.

FIG. 2 is an explanatory view of a tank filled with an adsorbent according to the first embodiment.

FIG. 3 is an explanatory view showing a method for manufacturing an adsorbent of Example 2.

[Explanation of symbols]

 1. ． ． Adsorbent, 2. ． ． Evaporative fuel treatment device, 3. ． ． tank,

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B01D 53/81 ZAB 53/40 53/42 B01J 20/28 ZAB A 7202-4G B01D 53/34 119

Claims (5)

[Claims] 1. An adsorbent characterized by being formed by finely pulverizing activated carbon fibers into a granular shape. 2. An adsorbent characterized in that either one or both of an acidic gas adsorbate and a basic gas adsorbate are attached to a finely pulverized body of activated carbon fibers. 3. The acid gas adsorbate according to claim 2, wherein the acidic gas adsorbate is 3-aminopropyltrihydrosilane, γ-aminopropylethoxysilane, dimethyltrimethylsilylamine, and N- (2-aminoethyl) -3-aminopropyl. An adsorbent, which is one or more compounds selected from the group of trimethoxysilane. 4. The adsorbate for basic gas according to claim 2, wherein 1 or 2 selected from the group consisting of L-tartaric acid, cobalt oxide, manganese oxide, acetylacetone cobalt, acetylacetone manganese, malic acid, and succinic acid.
An adsorbent, which is a compound of one or more kinds. 5. A porous adsorbent, comprising a porous body carrying the adsorbent according to claim 2, 3, or 4.