JPH11333290A - Adsorption molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high water cleaning capacity without deteriorating flow rate for a long period of time while water is made to pass through by constituting active carbons of a fibrous active carbon, a powdery active carbon and a granular active carbon and providing an adsorption molded body with a particular packing density, in the adsorption molded body made by integrally molding the active carbons and a fibril aggregate. SOLUTION: An adsorption molded body is made by integrally molding active carbons and a fibril aggregate and the active carbons comprises a fibrous active carbon, a powdery active carbon and a granular active carbon. The adsorption molded body has a packing density of 0.15-0.30 g/cc and a specific surface area of 850-2000 m<2> /g. The fibrous active carbon has a mean fiber diameter of 5-50 μm and its content is approximately 20-75 wt.%. The granular active carbon has a mean granule diameter of about 150 μm and its content is 2-40 wt.%. The powdery active carbon has a mean particle diameter of about 5-80 μm and its content is about 10-40 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorption molded article formed into a fixed shape, and more specifically, to a liquid phase,
Particularly, the present invention relates to an adsorption molded article which is suitable for water purification use, does not cause a decrease in flow rate for a long time when water is passed, and is capable of decomposing and removing free residual chlorine.

[0002]

2. Description of the Related Art A main use of an adsorption molded article is a water purifier for removing a odor in drinking water. In recent years, the miniaturization of water purifiers, as typified by faucet direct connection type water purifiers, has been progressing, and the performance of activated carbon has been desired to be improved so that it can be filled in a limited space and still have a higher water purification performance than before. .

At present, granular activated carbon having a particle diameter of more than 150 μm is generally used for removing free residual chlorine, which is a substance causing the odor of chalky, and the granular activated carbon is used after being filled in a container such as a plastic case. Often.
However, the granular activated carbon alone cannot provide much improvement in the performance of removing and removing free residual chlorine, that is, the so-called water purification performance.

[0004] The reason is that the efficiency of decomposing and removing free residual chlorine from water is improved as the contact efficiency between activated carbon and water, that is, as the outer surface area of activated carbon is increased, but in the case of granular activated carbon, the outer surface area is reduced due to its particle size. Because we can not get large
This is because there is a limit in improving the performance of decomposing and removing free residual chlorine, that is, the so-called water purification performance. For this reason, fibrous activated carbon and powdered activated carbon have been studied as alternatives to granular activated carbon.

[0005] Fibrous activated carbon has a characteristic that the water purification performance per unit weight is superior to that of granular activated carbon. However, the bulk density is usually about 1/5 to 1/10 that of granular activated carbon, and the water purification capacity per unit volume is high. As a result, there was a problem that the performance was only about the same as the granular activated carbon. Moreover, the price of fibrous activated carbon was about ten times as expensive as granular activated carbon or powdered activated carbon.

[0006] Powdered activated carbon has better water purification performance per unit weight than granular activated carbon, has a higher bulk density than granular activated carbon, and generally has higher water purification performance per unit volume than granular activated carbon and fibrous activated carbon. Has features. However, using only the powdered activated carbon as an integral part
There are problems that the bulk density of the adsorptive molded body is large, the water flow resistance is large, the flow rate is reduced, and dust is generated, resulting in poor operability.

As described above, granular activated carbon, fibrous activated carbon,
Adsorbents combining the above have been developed for the purpose of covering the drawbacks caused when powdered activated carbon is used alone.

For example, JP-A-4-271830 discloses an adsorbent obtained by mixing fibrous activated carbon and granular activated carbon.
No. 24637 discloses an adsorbent in which fibrous activated carbon and powdered activated carbon are mixed. However, in the former, the residual chlorine removal efficiency decreases as the granular activated carbon part ratio increases, and in the latter, the pressure loss increases and the flow rate decreases as the powdered activated carbon part ratio increases. Was. Therefore, in each case, a certain limit is imposed on the mixing ratio of granular activated carbon or powdered activated carbon in order to obtain the desired water purification performance and flow rate.

[0009]

SUMMARY OF THE INVENTION In view of the above points, the present invention provides a method for decomposing and removing free residual chlorine contained in water without causing a decrease in flow rate over a long period of time when passing water and achieving high water purification performance. It is intended to obtain an adsorbent having the same.

The present inventors have conducted various studies on the combination of various forms of activated carbon and the addition of fibril aggregates in order to solve the above-mentioned problems. As a result, fibrous activated carbon, granular activated carbon, powdered activated carbon, etc. It has been found that an adsorbent molded body obtained by mixing a certain amount of fibril aggregates and integrally molding to a constant density has excellent temporal stability of decomposition and removal efficiency of residual chlorine.

In addition, the inventors of the present invention have demonstrated that, in the above, the content of the granular activated carbon is within a certain range, and that the granular activated carbon is uniformly present in the adsorbent molded article, thereby exhibiting more excellent performance. In addition, it has been found that a molded article excellent in handleability can be produced.

The present inventors have made further studies based on the above findings, and have completed the present invention.

[0013]

That is, the present invention relates to an adsorption molded article obtained by integrally molding activated carbon and a fibril aggregate, wherein the activated carbon comprises fibrous activated carbon, powdered activated carbon, granular activated carbon, and An object of the present invention is to provide an adsorption molded article having a packing density of 0.15 to 0.30 g / cc.

[0014] In a preferred embodiment of the adsorption molded article of the present invention, the specific surface area of the adsorption molded article is 850 to 2000 m ^3.
/ G.

In a preferred embodiment of the adsorption molded article of the present invention, the fibrous activated carbon has a fiber diameter of 5 to 50 μm.

In a preferred embodiment of the adsorptive molded article of the present invention, the granular activated carbon is substantially uniformly dispersed in the adsorptive molded article, and 4 to 40% by weight based on the adsorptive molded article.
Be contained.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The adsorptive molded article of the present invention is an adsorptive molded article obtained by integrally molding activated carbon and fibril aggregates, and it is necessary that the activated carbon comprises fibrous activated carbon, powdered activated carbon, and granular activated carbon. is there. The above-mentioned integrally formed adsorbent molded body refers to one in which fibrous activated carbon, granular activated carbon, and powdered activated carbon are three-dimensionally organized into a predetermined shape by a fibril aggregate.

Such a molded article is, for example, a fibrous activated carbon,
Granular activated carbon, powdered activated carbon, and fibril aggregates are dispersed in water to form a uniform slurry, and the slurry is poured into a molding die having a predetermined shape having small holes through which water can pass by suction or pressure to form a molding die. Can be produced by draining water, dehydrating, demolding and drying. Note that a coagulant, an additive, and the like may be appropriately added to the slurry.

The packing density of the adsorption molded article of the present invention is 0.1
It needs to be 5 to 0.30 g / cc. A more preferred range is 0.16 g / cc as a lower limit, and still more preferably 0.17 g / cc. Also,
The upper limit is more preferably 0.28 g / cc,
More preferably, it is 0.27 g / cc. If the packing density is less than 0.15 g / cc, the strength of the molded body is not sufficient, and the molded body may be damaged when mounted on a container or the like.
If it exceeds 0.30 g / cc, the pressure loss during the passage of water through the molded article becomes large, and the water permeability cannot be sufficiently obtained.

The content of the fibril aggregate used in the adsorption molded article of the present invention is preferably 1 to 40% by weight. As a more preferred range, the lower limit is 3 parts by weight, and further preferably 4 parts by weight. On the other hand, the upper limit is more preferably 30 parts by weight, and still more preferably 25 parts by weight. The fibril aggregate is necessary for binding the activated carbons with the fibril aggregate and for the molded body to have practical strength. 1 fibril aggregate
If it is less than 30% by weight, the strength of the molded product is not sufficient,
If the amount is more than 10% by weight, the pressure loss at the time of passing water through the molded product is undesirably increased.

The fibril aggregate used in the adsorption molded article of the present invention is not particularly limited.
Wood pulp, synthetic pulp of polyethylene type, polypropylene type, polystyrene type, polyvinyl alcohol type and the like, and polyacrylonitrile fiber and aramid fiber obtained by beating and fibrillating can be suitably used alone or in combination. In addition, the fibril mentioned above refers to a fine fibrous structure having a thickness of several nm to several μm and branched into many branches.

The specific surface area of the adsorption molded article of the present invention is 850 to
It is preferably 2000 m ² / g. As a more preferred range, the lower limit is 900 m ² / g, and further preferably 9 m ² / g.
It is 50 m ² / g, while the upper limit is more preferably 1900 m ² / g. Specific surface area is 850m ² /
If the amount is less than 20 g, sufficient free chlorine removal performance cannot be obtained,
If it exceeds 00 m ² / g, the molded article is expensive and not practical.

The specific surface area is measured at a partial pressure of 0.05 to 0.20 by a low temperature nitrogen adsorption method and a BET multipoint method. For example, it is measured using a high-speed specific surface area / pore distribution measuring device (ASAP2010 manufactured by Shimadzu Corporation).

The average fiber diameter of the fibrous activated carbon used in the adsorption molded article of the present invention is preferably 5 to 50 μm. As a more preferable range, the lower limit is 7 μm, further preferably 8 μm, and the upper limit is more preferably 40 μm.
m, more preferably 35 μm. If the fiber diameter is less than 5 μm, the appearance of the molded article becomes poor or the pressure loss during water passage becomes large, which is not preferable. If the fiber diameter exceeds 50 μm, the external surface area in contact with the liquid becomes small, and the residual chlorine removal performance is reduced. Is undesirably reduced. The cross-sectional shape of the fiber is not particularly limited, but is preferably a flat plate shape, an elliptical shape, or a gourd-shaped shape capable of providing a large contact area with water. The specific surface area of the fibrous activated carbon used is 1000 m ^{2 in} order to sufficiently remove residual chlorine.
/ G or more is preferably used.

The average fiber diameter of the above-mentioned fibrous activated carbon refers to an average value obtained by randomly extracting 30 fibrous activated carbons as raw materials of a molded product and measuring the same with a microscopic microscope according to JIS R7601.

The content of the fibrous activated carbon used in the adsorption molded article of the present invention is preferably 20 to 75% by weight. As a more preferred range, the lower limit is 30% by weight, more preferably 35% by weight or more. The upper limit is more preferably 72% by weight, and even more preferably 70% by weight or less. 20% by weight of fibrous activated carbon
If it is less than 70%, the hardness of the molded body increases, and when used in a container or the like, a gap is easily formed between the container and the molded body, and the possibility that treated water leaks increases.
If the amount exceeds 10% by weight, the density of the compact cannot be increased and the amount of activated carbon decreases.

The raw material of the fibrous activated carbon used in the adsorptive molded article of the present invention is not particularly limited. For example, cellulose-based, polyacrylonitrile-based, phenolic resin-based, pitch-based, etc. are preferably used.

The average particle size of the granular activated carbon used in the adsorption molded article of the present invention is preferably 150 μm or more. It is more preferably at least 180 μm, even more preferably at least 200 μm. If the average particle diameter of the granular activated carbon is less than 100 μm, it is not preferable because the pressure loss at the time of liquid passage becomes large. The specific surface area of the granular coal used is 800 m ² /
It is preferable to use a substance of g or more.

The content of the granular activated carbon used in the adsorption molded article of the present invention is preferably 2 to 40% by weight. A more preferable range is 3% by weight as a lower limit, and a further preferable range is 4% by weight. On the other hand, a more preferable range as the upper limit is 37% by weight, and further preferably 35% by weight. When the content of the granular coal is less than 4% by weight, it is difficult to increase the packing density of the molded body, and the residual chlorine treatment capacity is reduced. There is a possibility that the pressure loss at the time increases and the water permeation amount decreases.

The raw material of the granular activated carbon used in the adsorptive molded article of the present invention is not particularly limited, and may be any of a plant type, a mineral type, and the like. May be applied.

It is preferable that the granular activated carbon used in the adsorption molded article of the present invention is substantially uniformly dispersed in the adsorption molded article. Granular charcoal has a larger particle size than other activated carbons to be used, so if it is unevenly distributed, practical strength of the adsorptive molded body may not be obtained or granular charcoal may fall off. This is because unevenness in density may occur in the manufactured molded article, and the flow path may be unevenly distributed during water flow, causing a leak.

In the above description, the expression that the granular activated carbon is substantially uniformly dispersed means, for example, that a plurality of samples having a constant weight in the range of about 0.5 to 1 g are collected from the adsorbent molded body, When the content of the granular activated carbon in the sample is obtained, it means that the dispersion of the value of the content of the granular carbon in a plurality of samples is 20% or less.

The average particle diameter of the activated carbon powder used in the adsorption molded article of the present invention is preferably 5 to 80 μm.
A more preferred range is 10 μm, more preferably 12 μm, as the lower limit. On the other hand, a more preferable range as the upper limit is 70 μm, and further preferably 60 μm.
It is. If the average particle size of the powdered charcoal is less than 5 μm, the handleability during the production of a molded article is poor. If it exceeds 80 μm,
Since the outer surface area of the powdered coal is reduced and the contact area with water is reduced, the residual chlorine removal performance is reduced, and the merit of using the powdered coal is less likely to be obtained. Also, the specific surface area of the powdered activated carbon to be used should be sufficient for the residual chlorine treatment capacity to be sufficient.
It is preferably 0 m ² / g or more.

The content of the activated carbon powder used in the adsorption molded article of the present invention is preferably 10 to 40% by weight. As a more preferable range, the lower limit is 12% by weight, and further preferably 15% by weight. On the other hand,
It is 37% by weight, more preferably 35 parts by weight.
When the content of the powdered charcoal is less than 10% by weight, the effect of increasing the contact area with water and improving the residual chlorine removal performance is reduced by using the powdered charcoal. The pressure loss at the time of passing water is large, and the amount of permeated water decreases.

The average particle size of the granular activated carbon and the powdered activated carbon is defined as 50% of the volume-based cumulative particle size distribution measured by a light transmission measurement method based on a natural sedimentation / centrifugal sedimentation method.
The particle size corresponds to, for example, measured using an automatic particle size distribution analyzer (CAPA-500 manufactured by Horiba, Ltd.).

The raw material of the powdered activated carbon used in the adsorptive molded article of the present invention is not particularly limited, and may be any of plant-based, mineral-based, and the like.

In the adsorptive molded article of the present invention, the strength of the molded article is obtained by appropriately adding an adhesive binder such as polyvinyl alcohol or by heat-fusing a heat-fusible fibril aggregate. Can also be increased.

[0038]

EXAMPLES The present invention will be described in detail based on examples, but the present invention is not limited to these examples.

[0039] (Example 1) mean fiber diameter 18 [mu] m, a specific surface area of 1450 m ² / g cellulosic fibrous activated carbon 68 wt% of an average particle diameter of 250 [mu] m, a specific surface area of 1750m ² /
g of coconut shell-based granular activated carbon 4% by weight, average particle diameter 20μ
sawdust-based powdered activated carbon 2 with a specific surface area of 1150 m ² / g
3% by weight, fibrillated acrylic fiber (A-
104) Disperse 5% by weight in water and stir to prepare a uniform slurry.
5. Demold, dry, outer diameter 40 mm, height 25 mm, weight 6.
2g, packing density 0.21g / cc, specific surface area 1320m
^{A 2} / g cylindrical shaped body was produced.

The molded body was loaded into a plastic case having an inner diameter of 40 mm to prepare a water purification cartridge, which was attached to a commercially available water purifier, and the water pressure was applied to the water purifier at 2 kgf / cm.
² Perform a test by passing tap water at a constant rate, and evaluate the residual chlorine removal efficiency of the water purifier (calculated from the residual chlorine concentration at the outlet of the water purifier with respect to the residual chlorine concentration of the raw water) and the flow rate of the water at the water purifier outlet. The change over time was measured. The test results are first
FIG. 2 and FIG.

[0041] (Example 2) mean fiber diameter 18 [mu] m, a specific surface area of 1450 m ² / g cellulosic fibrous activated carbon 47 wt% of an average particle diameter of 250 [mu] m, a specific surface area of 1750M ² /
g of coconut shell granular activated carbon 25% by weight, average particle diameter 20μ
sawdust-based powdered activated carbon 2 with a specific surface area of 1150 m ² / g
3% by weight, fibrillated acrylic fiber (A-
104) Disperse 5% by weight in water and stir to prepare a uniform slurry.
5. Demold, dry, outer diameter 40 mm, height 25 mm, weight 6.
7g, packing density 0.23g / cc, specific surface area 1380m
^{A 2} / g cylindrical shaped body was produced.

A water purification cartridge was prepared from the molded body in the same manner as in Example 1, and the same test as in Example 1 was performed. The change with time of the residual chlorine removal efficiency of the water purifier (calculated from the residual chlorine concentration at the outlet of the water purifier with respect to the residual chlorine concentration of the raw water) and the change with time of the flow rate of the water at the outlet of the water purifier were measured. The test results are shown in FIGS. 1 and 2, respectively.

[0043] (Example 3) Average fiber diameter 18 [mu] m, a specific surface area of 1450 m ² / g cellulosic fibrous activated carbon 36 wt% of an average particle diameter of 250 [mu] m, a specific surface area of 1750m ² /
g of coconut shell type granular activated carbon 26% by weight, average particle diameter 20μ
sawdust activated carbon 3 having a specific surface area of 1150 m ² / g
4% by weight, fibrillated acrylic fiber (A-Asei Kasei A-
104) Disperse 4% by weight in water and stir to prepare a uniform slurry.
Demold, dry, outer diameter 40 mm, height 25 mm, weight 7.
8g, packing density 0.26g / cc, specific surface area 1390m
^{A 2} / g cylindrical shaped body was produced.

A water purification cartridge was prepared from the molded body in the same manner as in Example 1, and the same test as in Example 1 was performed. The change with time of the residual chlorine removal efficiency of the water purifier (calculated from the residual chlorine concentration at the outlet of the water purifier with respect to the residual chlorine concentration of the raw water) and the change with time of the flow rate of the water at the outlet of the water purifier were measured. The test results are shown in FIGS. 1 and 2, respectively.

Comparative Example 1 95% by weight of fibrous activated carbon having an average fiber diameter of 18 μm and a specific surface area of 1450 m ² / g, 5% by weight of fibrillated acrylic fiber (A-104 manufactured by Asahi Kasei)
Is dispersed in water and stirred to prepare a uniform slurry. The slurry is suctioned, dehydrated, demolded and dried by a molding die having an inner diameter of 10 mm, and is dried to obtain an outer diameter of 40 mm, a height of 25 mm, a weight of 5.3 g, and a packing density of 0.18 g. / Cc and a cylindrical shaped body having a specific surface area of 1370 m ² / g were produced.

A water purification cartridge was prepared from the molded body in the same manner as in Example 1, and the same test as in Example 1 was performed. The change with time of the residual chlorine removal efficiency of the water purifier (calculated from the residual chlorine concentration at the outlet of the water purifier with respect to the residual chlorine concentration of the raw water) and the change with time of the flow rate of the water at the outlet of the water purifier were measured. The test results are shown in FIGS. 1 and 2, respectively.

Comparative Example 1 is a molded article composed only of fibrous activated carbon and fibrillated acrylic fiber which is an aggregate of fibrils, and has a low efficiency of removing residual chlorine when passing water.

[0048] (Comparative Example 2) Average fiber diameter 18 [mu] m, a specific surface area of 1450 m ² / g cellulosic fibrous activated carbon 53 wt% of an average particle diameter of 250 [mu] m, a specific surface area of 1750M ² /
g of coconut shell-based granular activated carbon (42% by weight) and fibrillated acrylic fiber (A-104 manufactured by Asahi Kasei Corporation) (5% by weight) are dispersed in water and stirred to prepare a uniform slurry. Demold, dry, outer diameter 40m
m, height 25mm, weight 6.8g, packing density 0.23g
/ Cc and a cylindrical shaped body having a specific surface area of 1500 m ² / g.

A water purification cartridge was prepared from the molded body in the same manner as in Example 1, and the same test as in Example 1 was performed. The change with time of the residual chlorine removal efficiency of the water purifier (calculated from the residual chlorine concentration at the outlet of the water purifier with respect to the residual chlorine concentration of the raw water) and the change with time of the flow rate of the water at the outlet of the water purifier were measured. The test results are shown in FIGS. 1 and 2, respectively.

Comparative Example 2 is a molded article which does not contain powdered activated carbon and is composed only of fibrous activated carbon, granular activated carbon, and fibrillated acrylic fiber which is an aggregate of fibrils, and has a low efficiency of removing residual chlorine when passing water.

[0051] (Comparative Example 3) an average fiber diameter of 18 [mu] m, a specific surface area of 1450 m ² / g cellulosic fibrous activated carbon 21 wt% of an average particle diameter of 250 [mu] m, a specific surface area of 1750m ² /
g of coconut shell-based granular activated carbon (34% by weight), average particle size 20μ
sawdust activated carbon 3 having a specific surface area of 1150 m ² / g
5% by weight, fibrillated acrylic fiber (A-Asei Kasei A-
104) Disperse 10% by weight in water and stir to prepare a uniform slurry, suction, dehydrate, demold, and dry with a mold having an inner diameter of 10 mm to obtain an outer diameter of 40 mm, a height of 25 mm, a weight of 9.8 g, Packing density 0.33 g / cc, specific surface area 130
A cylindrical shaped body of 0 g / cc was produced.

A water purification cartridge was prepared from the molded body in the same manner as in Example 1, and the same test as in Example 1 was performed. However, a predetermined flow rate could not be obtained from the initial stage. Not implemented. FIG. 2 shows the test results for the flow rate during the passage of water.

As described above, the water purification performance of each of the examples was superior to that of the comparative example, and the flow rate did not decrease for a long time during the passage of water.

[0054]

As described above, when applied to a water purifier, the adsorption molded article of the present invention is excellent in handleability due to the high density of the molded article. The capacity is high and, for example, in the removal and removal of free residual chlorine in water, free residual chlorine can be decomposed and removed without causing a decrease in the flow rate over a long period of time when passing water, and the effect of the present invention is large. It is.

[Brief description of the drawings]

FIG. 1 Changes with time of residual chlorine removal efficiency when passing water (3 L / min)

Fig. 2 Time-dependent change of flow rate when passing water (2 kgf / cm ² )

Claims (4)

[Claims] 1. An adsorption molded article obtained by integrally molding activated carbon and a fibril aggregate, wherein said activated carbon is made of fibrous activated carbon, powdered activated carbon, or granular activated carbon, and said adsorption molded article has a packing density of 0%. An adsorption molded article having a weight of 15 to 0.30 g / cc. 2. The specific surface area of the adsorption molded article is 850 to 2
The adsorption molded article according to claim 1, wherein the molded article is 000 m ² / g. 3. The fibrous activated carbon has a fiber diameter of 5 to 50 μm.
3. The adsorption molded article according to claim 1, wherein m is m. 4. The method according to claim 1, wherein the granular activated carbon is substantially uniformly dispersed in the adsorption molded body,
The adsorption molded article according to any one of claims 1 to 3, comprising 40% by weight.