JPH0852347A - Water treating filter material - Google Patents

Abstract

PURPOSE:To provide a water treating filter material excellent in the adsorbing capacity of a malodorous substance, especially, a moldy smell substance dissolved in water. CONSTITUTION:A water treating filter material is constituted of a fixed adsorbing layer 1 based on granular activated carbon with a BET specific surface area of 1500m<2>/g or more and a pore radius of 0.40nm or more and fibrous activated carbon with a BET specific surface area of 500m<2>/g or more and a pore radius of 0.35nm or more on a water inflow side and a fixed adsorbing layer 2 based on fibrous activated carbon with a BET specific surface area of 500m<2>/g or more and a pore radius of 0.35nm or more on a water outflow side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter material for water treatment, which is excellent in the adsorption performance of odorous substances dissolved in water, particularly moldy odorous substances.

[0002]

2. Description of the Related Art Activated carbon is classified into powdery and fibrous forms, each having its own characteristics. Since powdery granular activated carbon has a large surface pore radius, it is suitable for adsorbing substances having a relatively large molecular weight, and since it has a high packing density, it has a large adsorption amount per unit volume. However, since there is no fixed form and the packing density is high, the pressure loss is large. In addition, there is a problem that handleability and workability are poor and a part of activated carbon easily flows out.

On the other hand, fibrous activated carbon has a high adsorption rate,
Excellent adsorption to relatively low molecular weight substances. In addition, it is easy to handle and work, and the pressure loss is not so large. However, since it has smaller pores than powdered granular activated carbon, it is inferior in adsorption of compounds with large molecular weight. Moreover, since the packing density is low, there are problems such as a small amount of adsorption per unit volume.

In order to overcome the drawbacks when using powdered or fibrous activated carbons alone, for example, Jikken Sho 63-2
Japanese Patent No. 7828 proposes a filter adsorption unit for water purification in which a granular adsorption carbon and a fibrous activated carbon are combined to form a filtration adsorption layer. Since the granular activated carbon present on the water inlet side of this unit is a fluidized bed, the pressure loss does not increase, but since the packing density of the granular activated carbon is low, the adsorption amount per unit volume is low. In addition, the particle size of the granular activated carbon on the inflow side of water is 50 to 5000 μm, and if the particle size is smaller than that, the pressure loss increases and it becomes impossible to pass water. Activated carbon dust may flow out. Further, since the granular activated carbon is a fluidized bed, it is necessary to store it in a dedicated container such as plastic.

In addition, since the powdery granular activated carbon having a large particle size as used above has a small contact area with the adsorbent and has a slow adsorption rate, the adsorbing ability of the activated carbon cannot be sufficiently exhibited. . In addition, activated carbon with a large particle size
Generally, the pore radius is smaller than that of activated carbon having a small particle size, and even if it is combined with fibrous activated carbon, it does not compensate for the defects of fibrous activated carbon. Also, if the flow velocity of the water to be treated is increased, the pressure loss increases and the activated carbon existing on the inflow side is
In addition to the possibility of flowing into the outflow side and flowing out into the liquid, there is a problem that the activated carbon on the inflow side decreases and the adsorption performance of the filtration adsorption unit cannot be fully exhibited.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and takes advantage of the advantages of each of fibrous activated carbon and powdered activated carbon, has good adsorption and filtration performance, and has an odorous substance dissolved in water, particularly It is a technical subject to provide a filter material for water treatment which is excellent in the adsorption performance of a moldy odor substance.

[0007]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems. That is, the present invention has the following configurations. (1) On the water inflow side, a BET specific surface area of 1500 m ² / g or more and a granular active carbon with a pore radius of 0.40 nm or more, and a BET specific surface area of 5
It is composed of a fixed adsorption layer consisting mainly of fibrous activated carbon with a pore diameter of 00m ² / g or more and a pore radius of 0.35nm or more, and the water outflow side has a BET specific surface area of 500m ² / g or more and a pore radius of 0.35nm.
A filter material for water treatment, which is composed of a fixed adsorption layer whose main component is fibrous activated carbon of nm or more. (2) A water treatment filtration characterized in that the most outflow side of water of the fixed adsorption layer on the outflow side of water constituting the filter medium for water treatment described in (1) above is covered with a cloth filter. Material.

The present invention will be described in detail below.

In the water treatment filter of the present invention, as shown in FIG. 1, the inflow side of water is the fixed adsorption layer 1 containing powdered granular activated carbon and fibrous activated carbon as main components, and the outflow side of water is It is composed of a fixed adsorption layer 2 whose main component is fibrous activated carbon, and the fixed adsorption layers 1 and 2 are integrally formed. Further, as shown in FIG. 2, the most outflow side of water of the fixed adsorption layer 2 on the outflow side of water may be covered with a cloth-like filter 3, and further, as shown in FIG. The outer side of the adsorption layer 1 may also be covered with the cloth filter 4. The example of FIGS. 1 to 3 is an example in which the filter material for water treatment is formed into a cylindrical shape, but the fixed adsorption layers 1 and 2 and the filters 3 and 4 are laminated in a sheet shape or formed into a cylindrical shape. But it's okay.

The fixed adsorption layer 1 constituting the water inflow side of the water treatment filter material of the present invention is mainly composed of powdered granular activated carbon and fibrous activated carbon. Either powdered activated carbon having a particle size of less than 250 μm or granular activated carbon having a particle size of 250 μm or more may be used alone, or both may be used in combination. Particulate activated carbon, good specific surface adsorption of high molecular weight organic material dissolved in the water 1500 m ² / g or more, preferably has a particularly 2000~3500m ² / g, pore size 0.4nm
Above all, it is particularly preferable that the thickness is 0.4 to 0.5 nm.

Further, in order to increase the difference in the adsorption characteristics between the granular activated carbon and the fibrous activated carbon and to complement the portion of the activated carbon that is inferior in the adsorption characteristic with the granular activated carbon, the particle size of the granular activated carbon is small. It is more preferable that those having a particle size of 200 μm or less account for 90% by weight or more, and those having a particle size of 50 μm or less account for 50% by weight or more. The granular activated carbon may be made of coconut shell, coal, charcoal or the like.

Further, the fibrous activated carbon forming the fixed adsorption layer 1 together with the granular activated carbon has a specific surface area of 500 m ² / g or more and a pore radius of 0.35 nm or more with a good adsorbability of free chlorine dissolved in water. Are preferred.

The fixed adsorption layer 1 is mainly composed of powdered granular activated carbon and fibrous activated carbon, but as components other than activated carbon, thermoplastic synthetic fibers such as polyamide and polyester, acrylic fibers, low melting point binder fibers, etc. And fixed with these.

As described above, the powdered granular activated carbon and the fibrous activated carbon are present in the state of the fixed adsorption layer 1, and the fluidized granular activated carbon is present in the entangled interior of the synthetic fibers, and Since it is fixed to the synthetic fiber by heat fusion and its movement is suppressed, it is difficult to drop from the fixed adsorption layer 1.

The content of the granular active carbon and the fibrous activated carbon in the fixed adsorption layer 1 is preferably 10% by weight or more of the granular active carbon and the fibrous activated carbon, and the content of the granular active carbon is 40% by weight. It is preferably not less than 85% by weight. If the proportion of powdered activated carbon is less than the above, the ability of adsorbing relatively high molecular weight organic substances such as proteins and polysaccharide sugars dissolved in water is reduced, and it becomes difficult to cover the drawbacks of fibrous activated carbon. Absent.
If the proportion of the granular activated carbon is higher than the above, it becomes difficult to process the fixed adsorption layer 1. In addition, the bulk density of the fixed adsorption layer 1 is preferably 0.15 to 0.25 g / cm ^{3 in} order to impart excellent adsorption ability without increasing pressure loss.

Next, the fixed adsorption layer 2 constituting the water outflow side of the water treatment filter of the present invention is mainly composed of fibrous activated carbon, and the fibrous activated carbon has a specific surface area of 500 m ² / g. Above, preferably above 1000 m ² / g. If the specific surface area is less than 500 m ² / g, the ability to adsorb odorous substances dissolved in water, especially mildew odorous substances having a small molecular weight such as 2-methylisoborneol and dieosmin, is reduced.
Further, the above fibrous activated carbon preferably has a pore radius of 0.35 nm or more in order to adsorb a substance having a relatively low molecular weight.

In the fixed adsorption layer 2, fibrous activated carbon is 50
It is preferable to make up more than 50% by weight, and fibrous activated carbon is
If it is less than wt%, the ability to adsorb odorous substances dissolved in water, especially moldy odorous substances, decreases.

As another material for forming the fixed adsorption layer 2 together with the fibrous activated carbon, a heat-sealable synthetic fiber such as polyester, polyamide or polypropylene which improves moldability is preferable. Further, the bulk density of the fixed adsorption layer 2 is preferably 0.1 to 0.2 g / cm ³ in order to improve water permeability.

The type of fibrous activated carbon used in the fixed adsorption layers 1 and 2 may be any of cellulose type, acrylic type, phenol type, petroleum pitch type, coal pitch type and the like.

In the filter material for water treatment of the present invention, the cloth-like filter 3 is provided on the outer side of the fixed adsorption layer 2 constituting the outflow side of water.
Is preferably provided, and the cloth-like filter 4 may be provided outside the fixed adsorption layer 1. The material forming the cloth filters 3 and 4 is not particularly limited,
A woven or non-woven fabric of heat-fusible fibers with good processability is preferable, and a unit weight of 10 to 100 g / m ² is preferable in order to provide some breathability and excellent filterability. .

Next, an example of a method for producing the water treatment filter material of the present invention will be described.

First, fibrous activated carbon and synthetic fibers are supplied to open and mix to form a web, and then needle punching or heat treatment is performed to obtain a fibrous activated carbon sheet having a basis weight of 50 to 300 g / m ^2. . Then, a non-woven fabric having a basis weight of 10 to 100 g / m ² to be the filter 3 is wound around an iron core, and the above-mentioned fibrous activated carbon sheet is rolled into a cylindrical shape and heat-treated, and the adsorption fixing layer 2 is placed outside the filter 3 in a cylindrical shape. Shape. Further, powdered granular activated carbon, fibrous activated carbon, synthetic fibers and the like are fed into a water tank and mixed, and the molded product obtained above is dipped in the bath, sucked, and then dried to form the adsorption fixing layer 2. The adsorption fixing layer 1 is formed on the outside to obtain the water treatment filter material of the present invention.

The filter material for water treatment of the present invention can also be obtained as follows. First, fibrous activated carbon, synthetic fibers, etc. are mixed in a water tank, and a molding die is immersed in the bath and sucked to form a columnar molded body (for adsorption fixing layer 2). Next, powdered granular activated carbon, fibrous activated carbon, synthetic fibers, etc. are fed into another water tank and mixed, and the molding die holding the molded body obtained above is dipped in the bath and sucked and adsorbed. A columnar molded body continuous with the molded body for the fixed layer 2
(For adsorption fixed layer 1) is prepared. Thereafter, the molded body is taken out from the mold and dried to obtain the water treatment filter material of the present invention in which the adsorption fixing layers 1 and 2 are connected in series in a columnar shape.

Since the filter material for water treatment of the present invention uses the powdery granular activated carbon and the fibrous activated carbon which have different adsorption characteristics together, it can efficiently adsorb a wide range of substances from low molecular weight to high molecular weight. In addition, the efficient adsorption capacity of fibrous activated carbon with a high adsorption rate and the increased adsorption amount per unit volume of powdered granular activated carbon with a high packing density make it possible to exert a sufficient adsorption capacity within a fixed volume. In addition, it is possible to prevent an increase in pressure loss.

Further, the powdery granular activated carbon present on the water inflow side adsorbs a substance having a large molecular weight in water, which is difficult to be adsorbed by the fibrous activated carbon, and further, the fibrous activated carbon on the water inflow side slightly contains the above substance. Since it is adsorbed, it is possible to prevent the pores of the fibrous activated carbon existing on the outflow side from being clogged with a substance having a large molecular weight, and efficiently adsorb a low molecular weight substance such as a malodorous substance to the fibrous activated carbon. Therefore, the size of the filter can be reduced.

Further, the powdery granular activated carbon having fluidity is present in the fixed bed and its movement is suppressed, so that it is difficult to fall off.
Therefore, this filter material does not require a dedicated container, and can be easily molded according to the filter container. Since the filter material for water treatment of the present invention uses the powdery granular activated carbon and the fibrous activated carbon in combination, it can be manufactured at a lower cost than the filtration material made only of the fibrous activated carbon.

Further, if the side surface on the outflow side is covered with a cloth-like filter such as a non-woven fabric, even if coal dust is about to flow out, the leakage is prevented and the filtration performance is further improved.

The specific surface area in the present invention is 0.0 to 0. 0 by the BET multipoint method by the low temperature nitrogen adsorption method using "Bellsoap" automatic gas adsorption device manufactured by Bell Japan.
It is measured in the range of 3. The pore radius is measured by the MP method using the above automatic gas adsorption device. Further, the particle size is measured by a particle size distribution measuring device SALD-1100 manufactured by Shimadzu Corporation.

[0029]

EXAMPLES Next, the present invention will be specifically described by way of examples.

Examples 1 and Comparative Examples 1 and 2 As fibrous activated carbon, specific surface area 1600 m ² / g, pore radius 0.39
Using a coal pitch type of nm, 60% by weight of this fibrous activated carbon and 40% by weight of Melty 4080 (Polyester core-sheath composite fiber manufactured by Unitika Ltd.) are opened and mixed by a carding machine, and then needle punched. After that, a sheet having a basis weight of 67 g / m ² and a thickness of 0.5 mm was obtained through a heat roller.

Next, a non-woven fabric having a basis weight of 30 g / m ² composed of a core-sheath composite fiber containing polyethylene terephthalate as a core component and polyethylene as a sheath component was wrapped around an iron core coated with tetrafluoroethylene resin, and One sheet thus obtained was spirally wound and heat-treated at 150 ° C. for 180 minutes to obtain a molded body having an adsorption fixing layer 2 and a filter 3 having an outer diameter of 35 mm, an inner diameter of 18 mm and a length of 125 mm.

Further, the specific surface area is 1500 m ² / g, the pore radius is 0.39
Coal pitch based fibrous activated carbon of 47.5 wt% and specific surface area
Petroleum coke powder activated carbon with 2500m ² / g and pore radius 0.45nm
In a water tank mixed with 47.5% by weight of acrylic fiber and 5% by weight of acrylic fiber, the molded body obtained above was placed in a suction device, sucked, and then dried at 130 ° C. for 15 hours to obtain the adsorption fixing layer 2. A fibrous activated carbon, a powdered activated carbon and an acrylic fiber were contained on the outer side, and the adsorption fixed layer 1 was formed to have an outer diameter of 65 mm to obtain a water treatment filter material as shown in FIG. The powdered activated carbon used above should have a particle size of 200 μm or less.
95% by weight and 60% by weight had a particle size of 50 μm or less. Table 1 shows the evaluation results of the obtained water treatment filter material.

Further, as Comparative Example 1, a filter material for water treatment was formed only by the fibrous activated carbon-containing sheet constituting the adsorption fixed layer 2 of Example 1, and the performance was evaluated. Furthermore, Comparative Example 2
The adsorption fixed bed 1 on the water inlet side has a specific surface area of 980 m ² /
A water treatment filter material was formed in the same manner as in Example 1 except that coconut shell-based granular activated carbon having g, a pore diameter of 0.39 nm and a particle diameter of 300 μm or less was filled to the same size, and the performance was evaluated. did. This coconut shell-based granular activated carbon has a particle size of 200 μm.
The following substances accounted for 30% by weight, and those having a particle size of 50 μm or less accounted for 10% by weight.

[0034]

[Table 1]

In Table 1, the total amount of activated carbon means the total content of powdery granular activated carbon and fibrous activated carbon. In addition, the pressure loss indicates the pressure loss after passing water at 5 liters / minute for 10 minutes. Next, the filtration test was conducted on vitamin B ₁₂ having a molecular weight of 1357.
After the solution prepared by adjusting the concentration to 100 mg / liter with ion-exchanged water was passed at 4 liters / minute for 10 minutes, the case where no coloration was visually observed at the outlet was evaluated as ◯, and the case where it was recognized was evaluated as x.

Further, for the mold odor, 2-methylisoborneol was used as the mold odor substance. The mold odor 1 was ion-exchanged water, and the mold odor 2 was tap water, each of which had a concentration of 100 ng / liter. When the breakthrough point is 10 ng / liter, it is possible to treat 5 m ³ or more as ◎, 1 m ³ or more and less than 5 m ³ as ○, and the treatment amount is less than 1 m ^3. Was evaluated as Δ. In this case, the concentration of mold odor substance in the liquid was measured by gas chromatography. In addition, all the evaluation tests were performed by flowing the liquid from the outside (fixed adsorption layer 1 side) of the cylindrical object toward the inside perpendicularly to the surface of the filter medium.

In Example 1, vitamin B ₁₂ having a large molecular weight was well adsorbed, and there was no difference in the adsorption performance between the ion-exchanged water and the tap water in adsorbing the malodorous substance. Organic substances such as proteins, polysaccharides, and humic acids with relatively large molecular weight contained in water are efficiently removed by powdered activated carbon present on the inflow side of water, and the defects of fibrous activated carbon on the outflow side are eliminated. It was

On the other hand, in Comparative Example 1, there is no problem of pressure loss, and there is no problem in adsorption of mold odor substances in ion-exchanged water. However, when tap water containing a moldy odor substance was passed through, the performance dropped significantly compared to ion-exchanged water. Also, the adsorption performance of vitamin B ₁₂ having a large molecular weight was inferior.

Next, the pressure loss of Comparative Example 2 was the same as that of Example 1, but the adsorption rate was small, and the adsorbing ability of activated carbon could not be sufficiently exhibited under the passing conditions of this test. It was Moreover, since the granular activated carbon has a small pore radius of less than 0.4 nm, the adsorptivity of vitamin B ₁₂ having a large molecular weight was poor. Furthermore, regarding the adsorption of moldy substances, Comparative Example 1
Similarly, when tap water containing a moldy substance was passed through, the performance deteriorated extremely compared to ion-exchanged water. This is because the granular activated carbon present on the inflow side of water cannot remove organic substances having a relatively large molecular weight contained in tap water, and such granular activated carbon cannot compensate for the defects of fibrous activated carbon.

Example ² A non-woven fabric having a basis weight of 50 g / m ² made of a core-sheath type composite fiber containing polyethylene terephthalate as a core component and polyethylene as a sheath component was wound around the outside of the water treatment filter material obtained in Example 1. A filter was formed on the outside of the fixed adsorption layer 1 covering the fixed adsorption layer 1 to obtain a water treatment filter material as shown in FIG. Since the surface of the filter material, which is the water inflow side, is covered with a non-woven filter, the activated carbon did not come into contact with the hand and was easy to handle. A performance test similar to that of Example 1 was conducted using the above water treatment filter material, but substantially the same results as in Example 1 were obtained.

Example 3 95% by weight of coal pitch type fibrous activated carbon having a specific surface area of 1600 m ² / g and a pore radius of 0.39 nm cut into an average length of 3 mm and 5% by weight of acrylic short fiber having an average length of 5 mm Both are mixed in a water tank at a ratio of, and then the inner diameter is 35 mm and the length is 40 mm.
Insert the mm-shaped cylindrical mold set in the suction device, and suck it so that the mixture reaches 25 mm in the length direction.
A molded body having an outer diameter of 35 mm and a length of 25 mm was produced. Next, 45% by weight of coal pitch-based fibrous activated carbon with a specific surface area of 1500 m ² / g and a pore radius of 0.39 nm was cut into an average length of 3 mm, and coal coke with a specific surface area of 2500 m ² / g and a pore radius of 0.45 nm. The powdered activated carbon was mixed in 50% by weight and 5% by weight of acrylic short fibers having an average length of 5 mm in different water tanks. Further, the cylindrical mold holding the molded body obtained above was put into a water tank in a state where it was set in a suction device, and after sucking so that the remaining 15 mm of the mold was laminated, the molded body was removed from the mold. It was taken out and dried at 130 ℃ for 15 hours to obtain a cylindrical water treatment filter with an outer diameter of 35 mm and a length of 40 mm. The powdered activated carbon used above had a particle size of 200 μm or less at 95% by weight.
And particles having a particle size of 50 μm or less accounted for 60% by weight.

When tap water containing 100 ng / liter of 2-methylisoborneol as a malodorous substance was passed through the obtained filter material for water treatment at 1 liter / minute, a breakthrough point of 10 ng / liter was reached. By the time I was able to handle 700 liters.

Comparative Example 3 95% by weight of coal pitch-based fibrous activated carbon having a specific surface area of 1600 m ² / g and a pore radius of 0.39 nm cut into an average length of 3 mm and 5% by weight of acrylic short fiber having an average length of 5 mm A test was performed in the same manner as in Example 3 except that a columnar water-treating filter material having an outer diameter of 35 mm and a length of 40 mm was mixed to form a filter material for water treatment. The obtained water treatment filter material could only process 150 liters before reaching the breakthrough point of 10 ng / liter.

[0044]

EFFECTS OF THE INVENTION The filter material for water treatment of the present invention has good adsorbing and filtering performances by utilizing the respective advantages of fibrous activated carbon and powdered activated carbon, and adsorbs odorous substances, especially malodorous substances, dissolved in water. It has excellent performance and is suitable for household to commercial water purifiers, and it is possible to downsize the water purifier. Further, the filter material for water treatment of the present invention can be used not only for water purification treatment but also for liquid phase treatment in various fields such as decolorization and deodorization.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a water treatment filter material of the present invention.

FIG. 2 is a perspective view showing another embodiment of the water treatment filter material of the present invention.

FIG. 3 is a perspective view showing still another embodiment of the water treatment filter material of the present invention.

[Explanation of symbols] 1 fixed adsorption layer on the inflow side of water 2 fixed adsorption layer on the outflow side of water 3 filter on the outflow side of water 4 filter on the inflow side of water

Claims (3)

[Claims] 1. The BET specific surface area of the water inflow side is 1500 m ² /
g or more, powdered granular activated carbon with a pore radius of 0.40 nm or more, and BET
It is composed of a fixed adsorption layer consisting mainly of fibrous activated carbon with a specific surface area of 500 m ² / g or more and a pore radius of 0.35 nm or more, and the water outflow side has a BET specific surface area of 500 m ² / g or more and a pore radius of A filter material for water treatment, which is composed of a fixed adsorption layer mainly composed of fibrous activated carbon of 0.35 nm or more. 2. A water treatment characterized in that a fixed adsorption layer on the outflow side of water constituting the filter medium for water treatment according to claim 1 is covered with a cloth filter on the most outflow side of water. Filter material. 3. The powdery granular activated carbon used for the fixed adsorption layer on the water inflow side has a particle size of 200 μm or less occupying 90% by weight or more and a particle size of 50 μm or less occupying 50% by weight or more. Alternatively, the water treatment filter material according to claim 2.