JP2020110779A - Molding absorbent and production method of molding absorbent - Google Patents

Abstract

To provide a molding absorbent having a cross-section shape of an elliptical shape or a substantially elliptical shape and a plurality of through holes penetrating in a longitudinal direction.SOLUTION: A molding absorbent is a molding absorbent that contains activated carbon and a fibrous binder, has a shape of the molding absorbent of an elliptical columnar or substantially elliptically columnar shape, and has two or more of through holes penetrating in the longitudinal direction of the inside of the molding absorbent. The molding absorbent has a groove extending in the longer direction on an exterior surface and is preferably located at a center of an interval of the through holes where the most deep parts of the cross sectional shape of the groove of which the most deep parts of the cross sectional shape of the groove are adjacent.SELECTED DRAWING: Figure 4

Description

The present invention relates to a shaped adsorbent containing activated carbon as an adsorbent and a method for producing the shaped adsorbent.

BACKGROUND ART Conventionally, a shaped adsorbent using activated carbon as an adsorbent has been proposed as an adsorbent used in a water purifier. In such a shaped adsorbent, a shaped adsorbent having a circular cross-section has been proposed as being used in a faucet-integrated (water faucet-integrated) water purifier (for example, Patent Documents 1 and 2). reference).

Further, in recent years, faucets having a non-circular cross-sectional shape have been proposed due to diversification of faucet designs, and accordingly, molded adsorbents having a non-circular cross-sectional shape are also required. For example, in Patent Document 3, in a method for manufacturing a filter molded body used in a water purifier, a water purifying material and a bonding material are placed in a first mold having a circular cross section of an internal space, and heating and pressurizing are performed. After that, a molding step of molding a porous substrate having a circular cross section by hardening by cooling is performed, and a cross section of the internal space is a virtual ellipse with the substrate softened by heating after the molding step. Based on the above, the virtual ellipse is placed in a substantially elliptical second mold having protrusions projecting inward of the virtual ellipse at portions other than both ends of the minor axis of the virtual ellipse, pressurized, and then cured by cooling. A deformation step of deforming the cross-section of the base body from a circular shape to a substantially elliptical shape by doing so. reference).

JP, 2015-112518, A JP, 2016-059826, A JP, 2016-036788, A

It is an object of the present invention to provide a molded adsorbent having an elliptical or substantially elliptical cross section and having a plurality of through holes penetrating in the longitudinal direction. An object of the present invention is to provide a method for producing an adsorbent capable of producing a shaped adsorbent having an elliptical or substantially elliptical cross section by wet molding.

The shaped adsorbent of the present invention is a shaped adsorbent containing activated carbon and a fibrous binder, wherein the shape of the shaped adsorbent is an elliptic column or a substantially elliptic column, and inside the shaped adsorbent, the longitudinal direction It is characterized in that it has two or more through-holes penetrating through.

The method for producing a shaped adsorbent according to the present invention is a method for producing a shaped adsorbent which contains activated carbon and a fibrous binder and has two or more through-holes penetrating in the longitudinal direction inside the shaped adsorbent, which comprises activated carbon and fibers. Step of preparing a material slurry by mixing a particulate binder and water, a second step of producing a precursor by wet molding using the material slurry with two or more shaft members, and the precursor It is characterized by comprising a third step of drying the body to obtain a shaped adsorbent.

According to the present invention, a molded adsorbent having an elliptical or substantially elliptical cross section and having a plurality of through holes penetrating in the longitudinal direction can be obtained.

The perspective view which shows an example of a shaping|molding adsorption body. The II sectional view taken on the line of the shaping|molding adsorption body of FIG. The II-II sectional view taken on the line of the shaping|molding adsorption body of FIG. The perspective view which shows the other example of a shaping|molding adsorption body. FIG. 5 is a sectional view taken along line I-I of the shaped adsorbent of FIG. 4. II-II sectional view taken on the line of the shaping|molding adsorption body of FIG. The perspective view which shows an example of a compression type. The III-III sectional view taken on the line of the compression type of FIG. The longitudinal cross-sectional view which shows an example of a water purification cartridge. The side view which shows an example of the water purifier which contained the water purification cartridge. The side view which shows the cutting position of the shaping|molding adsorption body in a density measurement. The side view which shows the cutting position of the shaping|molding adsorption body in a density measurement.

[Molding adsorbent]
The shaped adsorbent of the present invention is a shaped adsorbent containing activated carbon and a fibrous binder, wherein the shape of the shaped adsorbent is an elliptic column or a substantially elliptic column, and inside the shaped adsorbent, the longitudinal direction It is characterized in that it has two or more through-holes penetrating through.

(shape)
The shaped adsorbent has an elliptic cylinder shape or a substantially elliptic cylinder shape. The cross-sectional shape of the shaped adsorbent is elliptical or substantially elliptical. The dimensions of the cross-sectional shape may be appropriately adjusted, but when used as a water purification cartridge, the major axis of the cross-sectional shape is preferably 11 mm to 100 mm, more preferably 20 mm to 50 mm, and the minor axis is preferably 10 mm to 90 mm. It is preferably 15 mm to 30 mm. The ratio of the major axis to the minor axis (major axis/minor axis) is preferably 1.25 or more, more preferably 1.50 or more, and preferably 2 or less, more preferably 1.85 or less. The length of the shaped adsorbent may be appropriately adjusted, but when used as a water purification cartridge, the length is preferably 40 mm to 200 mm. The shape of the shaped adsorbent may be a column having a constant cross-sectional shape, or may be a substantially column shape having a varying cross-sectional shape. The shape of the shaped adsorbent is preferably columnar.

The molded adsorbent has two or more through-holes penetrating in the longitudinal direction inside the molded adsorbent. These through holes serve as flow paths for raw water or purified water when the molded adsorbent is used in a purified water cartridge or the like. The cross-sectional shape of the through hole is not particularly limited, and examples thereof include a circular shape, a substantially circular shape, an elliptical shape, a substantially elliptical shape, a polygonal shape, and a rounded polygonal shape, and a circular shape is preferable.
The number of the through holes may be appropriately adjusted according to the cross-sectional area of the molded adsorbent and the cross-sectional area of the through holes, but is preferably 5 or less, more preferably 3 or less, and further preferably 2.
The two or more through-holes may have different sectional shapes, but it is preferable that the sectional shapes are all the same.

The cross-sectional shape of the through hole preferably has a maximum diameter (a diameter of a circumscribing circle) of 3 mm to 40 mm. The ratio of the maximum diameter of the cross-sectional shape of the through hole to the short diameter of the cross-sectional shape of the molded adsorbent (short diameter of molded adsorbent/maximum diameter of through hole) is preferably 1.25 or more, more preferably 2. It is 0 or more and preferably 4.0 or less, more preferably 3.5 or less, and further preferably 3.0 or less.

The proportion of the total cross-sectional area of the through holes in the cross-sectional area of the molded adsorbent is preferably 10.0 area% or more, more preferably 14.0 area% or more, and preferably 56.0 area% or less. , And more preferably 30.0 area% or less.
In the cross section of the shaped adsorbent, when the shortest distance from each point on the outer surface to the through hole is the filter layer thickness, the filter layer thickness is preferably 3.5 mm or more, more preferably 4.0 mm or more, It is preferably 38.5 mm or less, more preferably 30 mm or less, still more preferably 10 mm or less, and particularly preferably 8.0 mm or less.
The distance between the through holes (shortest distance between adjacent through holes) (di) is preferably 1.0 mm or more, more preferably 2.5 mm or more, further preferably 5.0 mm or more, and preferably 10 mm or less.

The positions of the two or more through-holes are not particularly limited, but they are preferably arranged in the major axis direction of the molded adsorbent. That is, it is preferable that the linear direction connecting the centers of the through holes and the major axis direction of the molded adsorbent are aligned.

The shaped adsorbent preferably has a groove extending in the longitudinal direction on the outer surface. Further, in the groove, when the straight line direction connecting the centers of adjacent through holes is defined as the x direction (direction in which the through holes are arranged), the deepest portion of the cross-sectional shape is the distance between the adjacent through holes in the x direction. It is preferably located in the center. By having such a groove, the distance from the outer surface of the molded adsorbent to the through hole can be made uniform.
The cross-sectional shape of the groove is not particularly limited, but a triangular shape or a substantially triangular shape is preferable. The maximum depth (de) of the groove is preferably 1.0 mm or more, more preferably 2.0 mm or more, preferably 20 mm or less, more preferably 10 mm or less, and further preferably 3.0 mm or less.
The ratio of the maximum depth of the groove to the minor axis of the sectional shape of the shaped adsorbent (groove depth/minor axis of the shaped adsorbent) is preferably 0.05 or more, more preferably 0.10 or more, and 1 It is preferably 0.40 or less, more preferably 1.20 or less, and further preferably 0.50 or less.

In the cross section of the shaped adsorbent, when the shortest distance from each point on the outer surface to the through hole is taken as the filter layer thickness, the maximum filter layer thickness value (T _max ) and the minimum filter layer thickness value (T _min ) The ratio (T _max /T _min ) is preferably 2.0 or less, more preferably 1.4 or less, still more preferably 1.2 or less.
The difference (T _max -T _min ) between the maximum value (T _max ) of the filter layer thickness and the minimum value (T _min ) of the filter layer thickness is preferably 10.0 mm or less, more preferably 7.0 mm or less, It is more preferably 4.0 mm or less, and particularly preferably 2.0 mm or less.

The overall density of the shaped adsorbent is preferably 0.25 g/mL or more, more preferably 035 g/mL or more, and 0.60 g/mL or less, more preferably 0.50 g/mL or less.
Further, when the longitudinal direction of the through hole is the z direction, the direction in which the two or more through holes are arranged in the cross section of the molded adsorbent body is the x direction, and the direction orthogonal to the x direction is the y direction, the molding is performed. When the adsorbent is cut in the yz plane passing through the centers of the respective through holes, the average density (D _out ) of the outer portion of the through holes provided at the outermost side in the x direction and the average of the portions between the through holes. The ratio (D _in /D _out ) to the density (D _in ) is preferably 0.98 or more, more preferably 0.99 or more, and further preferably 1.00 or more.
The difference (D _out −D _in ) between the average density (D _out ) of the portion outside the through hole and the average density (D _in ) of the portion between the through holes is preferably 0.025 g/mL or less, and more preferably It is preferably 0.020 g/mL or less.

When there are two through-holes, the molded adsorbent is divided into three by cutting in the yz plane passing through the center of the through-holes, and the central portion in the x-direction is the portion between the through-holes, and both side portions in the x-direction are outside the through-hole. It becomes the part of one.

When there are three through holes, the molded adsorbent is divided into four when cut along the yz plane passing through the center of the through holes. When the three through holes are a first through hole, a second through hole, and a third through hole in this order from one end in the x direction, a portion between the first through hole and the second through hole, and a second through hole A portion between the third through hole is a portion between the through holes, and an outer portion of the first through hole or the third through hole is an outer portion of the through hole.

An example of a specific shape of the shaped adsorbent will be described with reference to FIGS.
FIG. 1 is a perspective view showing an example of a shaped adsorbent. FIG. 2 is a cross-sectional view of the shaped adsorbent of FIG. 1 taken along the line I-I. FIG. 3 is a sectional view taken along line II-II of the molded adsorbent of FIG. FIG. 4 is a perspective view showing another example of the shaped adsorbent. FIG. 5 is a cross-sectional view of the molded adsorbent body of FIG. 4 taken along the line I-I. FIG. 6 is a sectional view taken along the line II-II of the shaped adsorbent of FIG. In each figure, the X direction represents the major axis direction of the sectional shape, the Y direction represents the minor axis direction of the sectional shape, and the Z direction represents the longitudinal direction of the molded adsorbent.

The molded adsorbent 1 shown in FIG. 1 has a substantially elliptic cylindrical shape, and has two through holes 2 penetrating in the longitudinal direction inside the molded adsorbent. The cross-sectional shape of the molded adsorbent 1 is constant, its major axis is 35.5 mm, its minor axis is 19.5 mm, and the ratio of its major axis to its minor axis (major axis/minor axis) is 1.82.
As shown in FIG. 2, the cross-sectional shape of the through hole 2 is circular, and the diameter is 8.0 mm. The through holes 2 are arranged in the major axis direction X of the sectional shape of the molded adsorbent. That is, the direction x of the straight line connecting the centers of the through holes 2 coincides with the direction X. The distance (di) between the two through holes 2 is 8.0 mm. The ratio (T _max /T _min ) between the maximum value (T _max ) of the filter layer thickness and the minimum value (T _min ) of the filter layer thickness is 1.50.
As shown in FIG. 3, the longitudinal direction z of the through hole 2 coincides with the longitudinal direction Z of the molded adsorbent 1.

The molded adsorbent 1 shown in FIG. 4 has a substantially elliptic cylindrical shape, and has two through holes 2 penetrating in the longitudinal direction inside the molded adsorbent. The cross-sectional shape of the molded adsorbent 1 is constant, its major axis is 35.5 mm, its minor axis is 19.5 mm, and the ratio of its major axis to its minor axis (major axis/minor axis) is 1.82.
As shown in FIG. 5, the cross-sectional shape of the through hole 2 is circular, and the diameter is 8.0 mm. The through holes 2 are arranged in the major axis direction X of the sectional shape of the molded adsorbent. That is, the direction x of the straight line connecting the centers of the through holes 2 coincides with the direction X. The distance (di) between the two through holes 2 is 8.0 mm.
As shown in FIGS. 4 and 5, the molded adsorbent 1 has a groove 3 extending in the longitudinal direction on the outer surface thereof. In the groove 3 in the x direction (the direction in which the through holes are arranged), the deepest part of the cross-sectional shape is located at the center of the interval between the adjacent through holes. The cross-sectional shape of the groove is substantially triangular, and the depth (de) of the groove is 2.4 mm. Filtration layer thickness maximum value (T _max) Toro layer thickness minimum value (T _min) and the ratio of (T _max / T _min) is 1.11.
As shown in FIG. 6, the longitudinal direction z of the through hole 2 coincides with the longitudinal direction Z of the molded adsorbent 1.

(Material)
The shaped adsorbent contains activated carbon and a fibrous binder. The activated carbon is an adsorbent, and the adsorbent has physical adsorption performance and chemical adsorption performance. Activated carbon is a carbon material having a specific surface area of 800 m ² /g or more. The activated carbon preferably contains particulate activated carbon.

The volume-based central particle diameter of the particulate activated carbon (particle diameter corresponding to cumulative 50% in volume cumulative distribution with 0 on the small diameter side) is preferably 20 μm or more, more preferably 30 μm or more, and further preferably 35 μm or more. It is preferably 100 μm or less, more preferably 80 μm or less, still more preferably 60 μm or less. When the central particle diameter is 20 μm or more, an appropriate void is formed between the activated carbon particles when the molded adsorbent is molded, so that the water flow pressure loss can be reduced. When the central particle diameter is 100 μm or less, the adsorption performance per unit mass of activated carbon is high, and the adsorption performance of the shaped adsorbent is further improved. In the present invention, the volume-based central particle size is measured by a laser diffraction/scattering type particle size distribution measuring device (MT3000 manufactured by Microtrac Bell).

The volume-based 10% particle diameter of the particulate activated carbon (particle diameter corresponding to 10% cumulative in the volume cumulative distribution where the small diameter side is 0) is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 15 μm or more. And is preferably 50 μm or less, more preferably 40 μm or less, still more preferably 30 μm or less. In the present invention, the volume-based 10% particle diameter is measured by a laser diffraction/scattering particle diameter distribution measuring device.

The content rate of particles having a particle diameter of 10 μm or less in the particulate activated carbon is preferably 2.0% by volume or less, more preferably 1.5% by volume or less, and further preferably 1.0% by volume or less. If the content of particles having a particle size of 10 μm or less is 2.0% by volume or less, an appropriate void is formed between the activated carbon particles when the molded adsorbent is molded, so that the water pressure loss is further reduced. can do. The lower limit of the content of particles having a particle diameter of 10 μm or less is 0% by volume. The content of particles having a particle size of 10 μm or less can be obtained from the volume cumulative distribution measured by a laser diffraction/scattering particle size distribution measuring device.

The specific surface area (BET method) of the particulate activated carbon is preferably 900 m ² /g or more, more preferably 950 m ² /g or more, further preferably 1000 m ² /g or more, and 1200 m ² /g or less, more preferably It is preferably 1150 m ² /g or less, more preferably 1100 m ² /g or less. When the specific surface area is 900 m ² /g or more, the adsorption performance of the activated carbon itself is high, and the adsorption performance of the obtained shaped adsorbent is further improved. When the specific surface area is 1200 m ² /g or less, the pore size is relatively large and the substance to be removed can be quickly adsorbed, so that the adsorption performance of the obtained molded adsorbent is further improved.

The pore volume (BET method) of the particulate activated carbon is preferably 0.40 ml/g or more, more preferably 0.45 ml/g or more, still more preferably 0.50 ml/g or more, 0.70 ml/g The following is preferable, more preferably 0.65 ml/g or less, still more preferably 0.60 ml/g or less. When the pore volume is 0.40 ml/g or more, the capacity capable of adsorbing a volatile organic compound such as chloroform is large, and the adsorption performance of the obtained molded adsorbent is further improved. When the pore volume is 0.70 ml/g or less, the density of the shaped adsorbent is increased, and the adsorption performance per unit mass of activated carbon is improved.

The average pore diameter (BJH method) of the particulate activated carbon is preferably 1.0 nm or more, more preferably 1.3 nm or more, still more preferably 1.5 nm or more, and preferably 2.5 nm or less, more preferably 2 nm. 0.2 nm or less, more preferably 2.0 nm or less. When the average pore size (BJH method) is 1.0 nm or more, the removal target substance is more likely to diffuse into the pores, and the adsorption rate is further improved. Since the distance to the inner wall becomes shorter and the intermolecular force becomes stronger, the adsorption force becomes higher.

The volume-based central particle diameter of the particulate activated carbon, the 10% particle diameter, and the content rate of particles having a particle diameter of 10 μm or less can be adjusted by pulverization and classification of the activated carbon. The crushing method is not particularly limited, and examples thereof include a jet mill, a ball mill and a stamp mill. The classification method is not particularly limited, and examples thereof include airflow classification and classification with a sieve. The specific surface area, pore volume, and average pore diameter of the particulate activated carbon can be adjusted by the activation conditions at the time of activated carbon production, the particle size distribution, and the like.

The activated carbon may contain fibrous activated carbon in addition to the particulate activated carbon. In this case, the content of the particulate activated carbon in the total activated carbon is preferably 85% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more. It is also preferable that the shaped adsorbent of the present invention contains only the particulate activated carbon as the activated carbon. In the present invention, activated carbon particles having an aspect ratio (major axis/minor axis) of 3 or less are referred to as particulate activated carbon, and those having an aspect ratio of more than 3 are referred to as fibrous activated carbon.

As the activated carbon, silver-impregnated activated carbon having silver impregnated on its surface may be used. By using silver-impregnated activated carbon, it is possible to impart antibacterial performance to the shaped adsorbent. As the silver-impregnated activated carbon, both silver-impregnated particulate activated carbon and silver-impregnated fibrous activated carbon can be used.

The activated carbon is obtained by carbonizing a carbon raw material and then activating steam and alkali. As the carbon raw material, synthetic resin such as phenol resin, coconut shell, wood, rice husk, coal and the like can be used. Among these, synthetic resin, coconut shell, and coal are preferable because they can increase the packing density when molded. In particular, synthetic resins such as phenolic resins and coconut shells are preferable because they have few impurities and have good adsorption performance even after pulverization.

As the particulate activated carbon, commercially available products can be used. Commercially available particulate activated carbon includes Hokuetsu manufactured by Ajinomoto Fine-Techno Inc.; Kuraray Coal (registered trademark) manufactured by Kuraray Chemical Co.; BAC (registered trademark) manufactured by Kureha Co.; MC Avasorb (registered trademark); Evatech Co., Ltd.; UES activated carbon (registered trademark);

The shaped adsorbent of the present invention contains, as an adsorbent, zeolite, titanium silicate, sodium titanate, aluminosilicate, titanium oxide, ion exchange resin, chelate resin, ion exchange fiber, chelate fiber, etc. as an adsorbent. You may. In this case, the content of activated carbon in the adsorbent is preferably 85% by mass or more, more preferably 87% by mass or more, and further preferably 89% by mass or more.

In the adsorbents other than the above-mentioned activated carbon, when a fibrous substance such as an ion exchange fiber or a chelate fiber is mixed, a void can be appropriately formed in the shaped adsorbent, and the fibrous substance is entangled with the particulate activated carbon. As a result, the mechanical strength of the shaped adsorbent can be increased.

The content of the adsorbent in the shaped adsorbent is preferably 90% by mass or more, more preferably 91% by mass or more, further preferably 92% by mass or more, and preferably 97% by mass or less, more preferably 95% by mass. % Or less. If the content of the adsorbent is 90% by mass or more, the adsorption performance of the shaped adsorbent is improved, and if it is 97% by mass or less, the content of the fibrous binder is relatively increased, and the machine of the shaped adsorbent is increased. Strength is improved.

The shaped adsorbent of the present invention contains a fibrous binder. Since the fibrous binder is held by being entangled with an adsorbent such as particulate activated carbon, the fibrous binder can be molded while maintaining the adsorption performance of activated carbon. Examples of the fibrous binder include acrylic fibers, cellulose fibers, polyethylene fibers, polypropylene fibers, polyacrylonitrile fibers, polyamide fibers, and aramid fibers. Among these, acrylic fibers and cellulose fibers are preferable because they easily hold the adsorbent, and acrylic fibers are particularly preferable because they can improve the mechanical strength of the molded adsorbent.

Fibrillated fibers are preferred as the fibrous binder. The fibrillated fiber is a fiber in which fibrils (small fibers) existing inside the fiber are made to appear on the fiber surface by frictional action or the like, and the fiber surface is fluffed. Fibrillation of the fibrous binder can be performed by a refiner treatment or a beating treatment.

The freeness of the fibrous binder is preferably 20 ml or more, more preferably 60 ml or more, further preferably 110 ml or more, particularly preferably 150 ml or more, 250 ml or less, more preferably 240 ml or less, further preferably 230 ml. It is as follows. When the freeness of the fibrous binder is 20 ml or more, the water pressure loss of the molded adsorbent can be reduced. In particular, in the case of the particulate activated carbon having a specific particle size distribution used in the present invention, when a fibrous binder having a freeness of 110 ml or more is used, the water pressure loss of the shaped adsorbent can be further reduced. The freeness of the fibrous binder refers to the freeness of the fibrous binder used for producing the shaped adsorbent. Specifically, it is the freeness of the fibrous binder contained in the slurry used to manufacture the shaped adsorbent.

The content of the fibrous binder is preferably 1 part by mass or more, more preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, and preferably 20 parts by mass or less, with respect to 100 parts by mass of the adsorbent. It is more preferably 15 parts by mass or less, still more preferably 10 parts by mass or less. When the content of the fibrous binder is 1 part by mass or more, the mechanical strength of the molded adsorbent is improved, and when it is 20 parts by mass or less, the water pressure loss of the molded adsorbent is further reduced.

The shaped adsorbent is preferably made by wet molding. By adopting wet molding, a molded adsorbent having a plurality of through holes can be easily manufactured.

[Method of manufacturing molded adsorbent]
The method for producing a shaped adsorbent according to the present invention includes a first step of preparing a material slurry by mixing activated carbon, a fibrous binder and water, and wet molding using two or more shaft members using the material slurry. , A second step of producing a precursor, and a third step of drying the precursor to obtain a shaped adsorbent.

(Slurry adjustment)
In the first step, a mixed material containing activated carbon and a fibrous binder is dispersed in water to prepare a slurry. The method of dispersing the mixed material is not particularly limited, but, for example, a beater can be used. The slurry may be prepared by adding materials such as activated carbon and a fibrous binder separately to water and then mixing them. When preparing the slurry, the amount of water used is preferably 2000 parts by mass or more, more preferably 3000 parts by mass or more, still more preferably 4000 parts by mass or more and 10000 parts by mass or less, relative to 100 parts by mass of the mixed material. Is preferable, more preferably 9000 parts by mass or less, and further preferably 8000 parts by mass or less.

(Suction molding)
In the second step, two or more shaft members as a suction mold are immersed in the slurry, the slurry is sucked by using a pump, and the mixed material is deposited on the surface of the shaft member. The shaft member on which the mixed material is deposited is pulled up to obtain a precursor of the shaped adsorbent. The shaft member has a through hole for suction so that the slurry can be sucked, and a pump is connected to a nozzle communicating with the through hole. The through hole of the shaft member is configured so that the solid content in the material slurry does not pass through.

The spacing between the shaft members (the spacing between the cross-sectional centers of adjacent shaft members) may be appropriately adjusted according to the number of shaft members used and the desired cross-sectional shape of the molded adsorbent. For example, when the number of shaft members is two, the distance between the shaft members is preferably 1.0 mm or more, more preferably 2.5 mm or more, preferably 38.5 mm or less, and more preferably 30.0 mm or less. ..

The time for sucking the slurry (molding time) is not particularly limited, but is preferably 50 seconds or less, more preferably 40 seconds or less, and further preferably 35 seconds or less. The shorter the molding time, the higher the productivity. The lower limit of the molding time is not particularly limited, but is usually about 5 seconds.

The cross-sectional shape of the shaft member may be appropriately selected according to the cross-sectional shape of the through hole of the molded adsorbent. For example, when the through-hole of the molded adsorbent has a circular cross-sectional shape, a shaft member having a circular cross-sectional shape may be used. The shaft member may or may not be removed from the precursor after the second step.

(Groove formation)
In the second step, it is preferable that a groove extending in the axial direction is formed on the surface of the precursor at the center between the axes of the adjacent shaft members. Since the precursor before drying is flexible, the groove can be easily formed. Further, it is preferable that the groove is formed by pressing a mold against the precursor. In wet molding using two or more shaft members, the density of the inter-shaft portion tends to be low. However, if the groove is formed by pressing the mold, the precursor in the inter-shaft portion is compressed and the density in the inter-shaft portion can be increased.

(compression)
In the second step, it is preferable that the entire precursor is compressed. By having the compression step, the density of the molded adsorbent finally obtained can be further increased, and the molded adsorbent having further excellent adsorption performance can be obtained. The compressibility of the precursor may be appropriately adjusted according to the density of the molded adsorbent finally obtained.

It should be noted that the groove formation and the compression may be performed on either one or both. When both the groove formation and the compression are performed, the compression may be performed after the formation of the groove, or the groove may be formed after the compression. Further, the groove formation and the compression may be performed at the same time.

When performing groove formation and compression at the same time, it is preferable to use a compression mold. As the compression mold, for example, the compression mold shown in FIGS. 7 and 8 can be used. FIG. 7 is a perspective view showing an example of a compression mold. FIG. 8 is a cross-sectional view of the compression type III-III line in FIG. 7.

The compression mold 10 shown in FIGS. 7 and 8 is composed of an upper mold 11 and a lower mold 12. The upper mold 11 and the lower mold 12 are provided with recesses 11a and 12a having semi-elliptical cross-sections on the sides facing each other. By combining the upper mold 11 and the lower mold 12, an elliptic cylindrical space is formed by the recesses 11a and 12a. The dimensions of the recesses 11a and 12a may be appropriately adjusted according to the dimensions of the molded adsorbent after drying.

Further, the upper and lower dies 11 and 12 are provided with ridges 11b and 12b extending in the longitudinal direction, respectively, in the widthwise central portions of the recesses. The cross-sectional shape of these ridges 11b and 12b is a rounded triangular shape, and the top is located at the center in the width direction of the precursor. The tops of the ridges 11b and 12b are formed so as to coincide with the central portion between the axes of the two shaft members (portions indicated by two-dot chain lines).

By sandwiching the precursor of the shaped adsorbent between the upper mold 11 and the lower mold 12 of the compression mold 10, compression of the precursor and formation of grooves can be performed simultaneously. The compression rate during compression can be controlled by adjusting the dimensions of the precursor. When forming or compressing a groove, it is possible to connect a tube connected to a pump to both ends of each shaft member and drive the pump to suck (while dehydrating the molded adsorbent). preferable.

(Dry)
In the third step, the precursor is dried to obtain a shaped adsorbent. The drying temperature is preferably 100°C to 120°C, and the drying time is preferably 4 hours to 6 hours. The shaft member may be removed or used as it is. For example, if the shaft member that can be used as a water purification cartridge is used, the water purification cartridge can be obtained by drying the precursor.

The fibrous binder may be melted or deformed in the drying step depending on the kind of the fibrous binder and the drying condition of the deposit. When the degree of deformation of the fibrous binder increases, the volume of voids in the molded adsorbent tends to decrease, resulting in higher water pressure loss in the water purification cartridge and lower dimensional stability. Therefore, it is preferable to select the drying condition of the deposit according to the kind of the fibrous binder, and it is more preferable to set the drying temperature low.

[Water purification cartridge]
The molded adsorbent of the present invention can be suitably used in a water purification cartridge used in a water purifier. Examples of the configuration of the water purification cartridge include a configuration including two or more tubular shaft members and a molded adsorbent laminated on the outer surface of the shaft members. By having the shaft member, the mechanical strength of the molded adsorbent can be increased. As the shaft member, a porous cylindrical member having a through hole is preferable. The shape of the porous tubular member is not particularly limited, and examples thereof include a cylindrical shape and a polygonal column shape. Resin, metal or the like can be used as the material of the porous tubular member. Further, since the activated carbon particles can be prevented from entering the inside of the shaft member, the shaft member is preferably a porous tubular member having a nonwoven fabric wound around the outer surface.

An example of a specific configuration of the water purification cartridge will be described with reference to FIG. The water purification cartridge is not limited to the mode shown in FIG. The water purification cartridge 20 includes a cylindrical shaft member 21, a molded adsorbent 1 laminated on the outer surface of the shaft member 21, a connecting member 22 attached to one end of the shaft member 21, and the shaft. And a cover 23 attached to the other end of the member 21. The shaft member 21 is cylindrical and has a plurality of through holes 21a. A non-woven fabric 24 is wound around the outer surface of the shaft member 21. The connection member 22 is formed to be connectable to the water purifier body. Further, a non-woven fabric 25 that protects the shaped adsorbent 1 is wrapped around the shaped adsorbent 1.

The water purification cartridge 20 shown in FIG. 9 uses the outside of the molded adsorbent 1 as a raw water flow path. Raw water passes through the shaped adsorbent 1 and flows into the shaft member 21. At this time, it is purified by an adsorbent (not shown) contained in the shaped adsorbent 1 to become purified water. The obtained purified water is discharged from the connection part 22.

The water purifier in which the molded adsorbent of the present invention is used is not particularly limited as long as it uses the water purification cartridge. As the water purifier, for example, a faucet direct connection type that is directly attached to the end of a faucet; a stationary type that is installed near a faucet by connecting a faucet or a branch faucet provided on the faucet with a hose or piping; a water purification cartridge for the faucet Built-in faucet (water faucet integrated type); under-sink type installed under the sink.

FIG. 10: is a side view which shows the preferable aspect of a water purifier. The water purifier 30 is a water faucet-integrated water purifier in which the water purification cartridge 20 is replaceably incorporated in the faucet. The water purifier 30 has a separable head 31 and a body 32. The head 31 and the body 32 are separated and the water purification cartridge 1 is mounted inside the water purifier 30.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples and is appropriately modified and implemented within a range compatible with the gist of the above and the following. It is also possible that they are all included in the technical scope of the present invention.

1. Evaluation method [center particle size]
The central particle size of the particulate activated carbon was measured using a laser diffraction/scattering particle size distribution measuring device (Microtrac, model “MT3300” manufactured by Nikkiso Co., Ltd.). Regarding the particle size distribution, the range of the particle size of 0.021 μm to 2000 μm was divided into 132 on a logarithmic scale, and the volume of activated carbon particles having the particle size of each section was measured.

[density]
The overall dimensions of the molded adsorbent (excluding the shaft member) were measured. Next, the molded adsorbent was divided into three in the width direction using a cutter knife, and the shaft member was removed. Specifically, as shown by alternate long and short dash lines A and B in FIGS. 11 and 12, a straight line (YZ plane (Y direction) in the cross section of the molded adsorbent, which extends in the thickness direction and passes through the center of each shaft member. Was cut in the minor axis direction of the cross-sectional shape, and the Z direction was cut in the longitudinal direction of the molded adsorbent body)). The cut parts were the first shaft outer part 1a, the inter-shaft part 1b, and the second shaft outer part 1c, and the mass was measured after drying. In addition, a 3D model of each part was created from the overall dimensions, and the volume of each part was calculated. Finally, the density of the entire molded adsorbent and each part was calculated.

[Initial water turbidity]
A water purification cartridge was produced using the molded adsorbent, and this water purification cartridge was attached to the faucet. The static water pressure was set to 0.75 MPa, and the faucet was fully opened while the water was switched to purified water. The water temperature was 20±15°C. Using a graduated cylinder, 300 mL of initial water flow was sampled, and the turbidity of this initial water flow was measured. The turbidity was measured using a turbidimeter (“Turb 430T” manufactured by WTW).

[Purified water filtration flow rate measurement]
A water purification cartridge was manufactured using the molded adsorbent, and this water purification cartridge was attached to the faucet. Based on JIS S 3201 (2017) "household water purifier test method", the purified water flow rate at a dynamic water pressure of 0.1 MPa was measured.

2. Manufacture of molded adsorbents (density evaluation)
(1) Formed adsorbent No. 1-5
(Slurry adjustment)
89.8% by mass of particulate activated carbon (center particle size: 30.4 μm) as an adsorbent, 5.2% by mass of other adsorbents, acrylic fiber as a fibrous binder (freeness of 120-220 mL by beater) Mixed material containing 5.0% by mass) was prepared. 100 parts by mass of this mixed material was dispersed in 5000 parts by mass of water to prepare a slurry.

(Wet molding)
A precursor of a molded adsorbent was molded by wet molding using the slurry. Specifically, a tube connected to a pump was connected to both ends of each of the two shaft members. The shaft member connected with this tube was immersed in a tank filled with the slurry, and then the pump was driven to suck the slurry to deposit the mixed material on the surface of the shaft member.

As the shaft member, a resin porous cylindrical member having a nonwoven fabric wound around the outer surface (inner diameter: 5.5 mm, outer diameter: 8.0 mm, total length: 87 mm) was used. In addition, the shape of the molded adsorbent formed on the outer surface of the shaft member is an elliptic column having an elliptical cross-sectional shape (long diameter is 35.5 mm or more, short diameter is 19.5 mm or more (apparent volume 43 to 50 mL)). (Two through holes) were adjusted.

The two shaft members were arranged so as to be parallel to each other, and the distance between the shafts (the distance between the center parts of the cross sections of the shaft members) was 16.0 mm. At this time, the driving time of the pump was adjusted so that the amount of the mixed material deposited on the surface of the shaft member was 5.75 mm or more. The amount of the mixed material deposited was measured by measuring the amount deposited on the outer side of each shaft member (the side where the two shaft members do not face each other) in the cross section of the precursor of the molded adsorbent.

(compression)
A compression type was used for compression. The compression mold is a pair of upper mold and lower mold. A recess having a semi-elliptical cross-sectional shape is formed in each mold, and when the upper and lower molds are combined, an elliptic cylindrical space is formed. The elliptic cylindrical space formed when the upper and lower molds are combined has a thickness direction length of 19.3 mm, a width direction length of 35.3 mm, and a longitudinal direction length of 85.0 mm. In the upper and lower molds, a semi-elliptical recess has a ridge extending in the longitudinal direction at the center in the width direction. The ridge has a rounded triangular cross section, a height of 2.6 mm, and a bottom length of 7.2 mm. The ridges are formed so that the tops thereof coincide with the widthwise central portion of the molded adsorbent (the central portion between the axes of the two shaft members).

The compression was performed by pressing a compression mold against the precursor of the shaped adsorbent. The time for pressing the compression mold against the shaped adsorbent was 60 seconds. Also, connect the tubes connected to the pump to both ends of each shaft member, press the compression mold while driving the pump and sucking (while dehydrating the molded adsorbent), and after a predetermined time, compress I removed the mold.

Grooves were formed in the precursor after compression, parallel to the axial direction, throughout the precursor. The groove had a triangular cross section and was formed so that its apex coincided with the middle of the two shaft members. The depth of the tip of the groove was 2.4 mm, and the width of the groove (width of the shallowest part) was 7.0 mm.

[Dry]
The shaped adsorbent No. 1 in which the adsorbent was laminated on the outer surface of the shaft member was obtained by drying the precursor in which the grooves were formed at 120° C. for 4 hours. 1-5 were obtained.

(2) Formed adsorbent No. 6-9
The molded adsorbent No. Molded adsorbent Nos. 1 to 5 except that no compression was performed. In the same manner as in 1 to 5, the molded adsorbent No. 6-9 were produced.

The obtained molded adsorbent No. For 1 to 9, the density of the entire molded adsorbent, and the outside of the first axis, the inter-axis part, and the outside of the second axis were calculated. The results are shown in Table 1.

Forming adsorbent No. Nos. 6 to 9 were dried without compression after wet molding. These molded adsorbents No. In Nos. 6 to 9, the ratio of the average density outside the shaft to the density in the inter-shaft portion (inter-shaft portion/outer shaft average) is 0.97 or less. That is, the difference between the density outside the shaft and the density between the shafts is large. This is considered to be because in wet molding using two shaft members, the adsorbents of both shaft members compete with each other in the shaft-to-shaft portion during slurry suction, so that the density of the shaft-to-shaft portion becomes low.

Forming adsorbent No. Nos. 1 to 5 are subjected to compression using a compression mold after wet molding and before drying, and in particular, the inter-axial portion is largely compressed by the ridges on the inner surface of the compression mold. Therefore, these molded adsorbent No. In Nos. 1 to 5, the ratio between the average density outside the axis and the density between the axes (inter-axis portion/average outside the axis) is 0.99 or more. That is, the difference between the density outside the shaft and the density between the shafts is small.

3. Manufacturing of molded adsorbent (Evaluation of initial flow water turbidity)
(1) Formed adsorbent No. 21, 22
(Slurry adjustment)
89.8% by mass of particulate activated carbon (center particle size: 30.4 μm) as an adsorbent, 5.2% by mass of other adsorbents, acrylic fiber as a fibrous binder (freeness of 120-220 mL by beater) Mixed material containing 5.0% by mass) was prepared. 100 parts by mass of this mixed material was dispersed in 5000 parts by mass of water to prepare a slurry.

(Wet molding)
A precursor of a molded adsorbent was molded by wet molding using the slurry. Specifically, a tube connected to a pump was connected to both ends of each of the two shaft members. The shaft member connected with this tube was immersed in a tank filled with the slurry, and then the pump was driven to suck the slurry to deposit the mixed material on the surface of the shaft member.

As the shaft member, a resin porous cylindrical member having a nonwoven fabric wound around the outer surface (inner diameter: 5.5 mm, outer diameter: 8.0 mm, total length: 87 mm) was used. In addition, the shape of the molded adsorbent formed on the outer surface of the shaft member is an elliptic column having an elliptical cross-sectional shape (long diameter is 35.5 mm or more, short diameter is 19.5 mm or more (apparent volume 43 to 50 mL)). (Two through holes) were adjusted.

The two shaft members were arranged so as to be parallel to each other, and the distance between the shafts (the distance between the center parts of the cross sections of the shaft members) was 16.0 mm. At this time, the driving time of the pump was adjusted so that the amount of the mixed material deposited on the surface of the shaft member was 5.75 mm or more. The amount of the mixed material deposited was measured by measuring the amount deposited on the outer side of each shaft member (the side where the two shaft members do not face each other) in the cross section of the precursor of the molded adsorbent.

(compression)
A compression type was used for compression. The compression mold is a pair of upper mold and lower mold. A recess having a semi-elliptical cross-sectional shape is formed in each mold, and when the upper and lower molds are combined, an elliptic cylindrical space is formed. The elliptic cylindrical space formed when the upper and lower molds are combined has a thickness direction length of 19.3 mm, a width direction length of 35.3 mm, and a longitudinal direction length of 85.0 mm.

The compression was performed by pressing a compression mold against the precursor of the shaped adsorbent. The time for pressing the compression mold against the shaped adsorbent was 60 seconds. Also, connect the tubes connected to the pump to both ends of each shaft member, press the compression mold while driving the pump and sucking (while dehydrating the molded adsorbent), and after a predetermined time, compress I removed the mold.

(Dry)
The compressed precursor is dried at 120° C. for 4 hours, and a molded adsorbent No. 1 in which an adsorbent is laminated on the outer surface of the shaft member. 21 and 22 were obtained.

(2) Formed adsorbent No. 23, 24
The molded adsorbent No. In the manufacturing method of Nos. 21 and 22, except for the fact that compression was not performed, the molded adsorbent No. In the same manner as in Nos. 21 and 22, the molded adsorbent No. 23 and 24 were produced.

The obtained molded adsorbent No. For Nos. 21 to 24, the mass, density, and initial flow water turbidity of the entire shaped adsorbent were evaluated. The results are shown in Table 2.

Forming adsorbent No. Nos. 23 and 24 are dried without compression after wet molding. These molded adsorbents No. At 23 and 24, the turbidity of the initial water is high. When the compression is not applied, the density of the inter-axial portion is low and the voids are large. Therefore, it is considered that the fine particles of the activated carbon in the inter-axis portion are flowing out together with the purified water.

Forming adsorbent No. 21 and 22 are compressed using a compression mold after wet molding and before drying. These molded adsorbents No. 21 and 22, the molded adsorbent No. Compared with 23 and 24, the turbidity of the initial water is lower. It is considered that this is because the voids inside the molded adsorbent could be reduced by applying compression, and the fine particles of activated carbon were suppressed from flowing out together with purified water.

4. Manufacture of molded adsorbent (groove depth evaluation)
(1) Formed adsorbent No. 25-28
(Slurry adjustment)
89.8% by mass of particulate activated carbon (center particle size: 30.4 μm) as an adsorbent, 5.2% by mass of other adsorbents, acrylic fiber as a fibrous binder (freeness of 120-220 mL by beater) Mixed material containing 5.0% by mass) was prepared. 100 parts by mass of this mixed material was dispersed in 5000 parts by mass of water to prepare a slurry.

(Wet molding)
A precursor of a molded adsorbent was molded by wet molding using the slurry. Specifically, a tube connected to a pump was connected to both ends of each of the two shaft members. The shaft member connected with this tube was immersed in a tank filled with the slurry, and then the pump was driven to suck the slurry to deposit the mixed material on the surface of the shaft member.

As the shaft member, a resin porous cylindrical member having a nonwoven fabric wound around the outer surface (inner diameter: 5.5 mm, outer diameter: 8.0 mm, total length: 87 mm) was used. In addition, the shape of the molded adsorbent formed on the outer surface of the shaft member is an elliptic column having an elliptical cross-sectional shape (long diameter is 35.5 mm or more, short diameter is 19.5 mm or more (apparent volume 43 to 50 mL)). (Two through holes) were adjusted.

The two shaft members were arranged so as to be parallel to each other, and the distance between the shafts (the distance between the center parts of the cross sections of the shaft members) was 16.0 mm. At this time, the driving time of the pump was adjusted so that the amount of the mixed material deposited on the surface of the shaft member was 5.75 mm or more. The amount of the mixed material deposited was measured by measuring the amount deposited on the outer side of each shaft member (the side where the two shaft members do not face each other) in the cross section of the precursor of the molded adsorbent.

(compression)
A compression type was used for compression. The compression mold is a pair of upper mold and lower mold. A recess having a semi-elliptical cross-sectional shape is formed in each mold, and when the upper and lower molds are combined, an elliptic cylindrical space is formed. The elliptic cylindrical space formed when the upper and lower molds are combined has a thickness direction length of 19.3 mm, a width direction length of 35.3 mm, and a longitudinal direction length of 85.0 mm.

Forming adsorbent No. For 25-28, different compression types were used.
Forming adsorbent No. In No. 25, the upper and lower molds having no convex stripe were used.
Forming adsorbent No. In the upper and lower molds used in Nos. 26 to 28, a semi-elliptical recess has a ridge extending in the longitudinal direction at the center in the width direction. The cross-sectional shape of the ridge is rounded triangular. The ridges are formed so that the tops thereof coincide with the widthwise central portion of the molded adsorbent (the central portion between the axes of the two shaft members). And, the dimension of the cross-sectional shape of the ridge is the molded adsorbent No. In No. 26, the height was 2.0 mm and the length of the base was 5.6 mm. Forming adsorbent No. In No. 27, the height was 2.6 mm and the base length was 7.2 mm. Forming adsorbent No. In No. 28, the height was 3.2 mm and the length of the base was 11.4 mm.

The compression was performed by pressing a compression mold against the precursor of the shaped adsorbent. The time for pressing the compression mold against the shaped adsorbent was 60 seconds. Also, connect the tubes connected to the pump to both ends of each shaft member, press the compression mold while driving the pump and sucking (while dehydrating the molded adsorbent), and after a predetermined time, compress I removed the mold.

Forming adsorbent No. In 26-28, the precursor after compression had grooves formed throughout the precursor, parallel to the axial direction. The groove had a triangular cross section and was formed so that its apex coincided with the middle of the two shaft members.

(Dry)
The compressed precursor is dried at 120° C. for 4 hours, and a molded adsorbent No. 1 in which an adsorbent is laminated on the outer surface of the shaft member. 25-28 were obtained. The molded adsorbent No. No. 28 cracked along the groove after drying.

The obtained molded adsorbent No. For 25 to 27, the mass, density and purified water filtration flow rate of the entire molded adsorbent were evaluated. The results are shown in Table 3.

As shown in Table 3, by forming the groove so that the apex coincides with the center of the interval between the two shaft members, the purified water filtration flow rate is improved. It is considered that this is because by forming a groove in the center between the two shaft members, the distance (filter layer thickness) from the surface of the molded adsorbent in the inter-shaft portion to the shaft member was shortened. When two shaft members are used, if the shaped adsorbent has an elliptical cross-sectional shape, the filter layer in the inter-axis portion becomes thicker than the filter layer outside the shaft. In this case, the raw water comes to flow outside the shaft, making it difficult to utilize the inter-shaft portion. However, it is considered that by forming the grooves and thinning the filter in the inter-shaft portion, the raw water easily flows in the inter-shaft portion, and the purified water filtration flow rate is improved.

The shaped adsorbent of the present invention can be suitably used as an adsorbent for a water purifier.

1: molded adsorbent, 2: through hole, 3: groove, 10: compression mold, 11: upper mold, 12: lower mold, 20: water purification cartridge, 21: shaft member, 22: connection member, 23: cover, 24 : Nonwoven fabric, 25: Nonwoven fabric, 30: Water purifier, 31: Head, 32: Body

Claims (9)

A shaped adsorbent containing activated carbon and a fibrous binder,
The shape of the shaped adsorbent is an elliptic cylinder or a substantially elliptic cylinder,
A molded adsorbent having two or more through-holes penetrating in the longitudinal direction inside the molded adsorbent. The molded adsorbent according to claim 1, wherein a ratio of a major axis to a minor axis of the molded adsorbent (major axis/minor axis) is 1.25 to 2 in the cross section of the molded adsorbent. The longitudinal direction of the through hole is the z direction,
In the cross section of the molded adsorbent, when the direction in which the two or more through holes are arranged is the x direction and the direction orthogonal to this x direction is the y direction,
When the shaped adsorbent is cut in the yz plane passing through the center of each through hole, the average density (D _out ) of the outer portion of the through hole provided at the outermost side in the x direction and the portion between the through holes. The molded adsorbent according to claim 1 or 2, having a ratio (D _in /D _out ) to the average density (D _in ) of 0.98 or more. The molded adsorbent has a groove extending in the longitudinal direction on the outer surface,
The molded adsorbent according to any one of claims 1 to 3, wherein the deepest part of the cross-sectional shape of the groove is located at the center of the interval between adjacent through holes. In the cross section of the molded adsorbent, when the shortest distance from each point on the outer surface to the through hole is the filter layer thickness,
The ratio (T _max /T _min ) of the maximum value (T _max ) of the filter layer thickness and the minimum value (T _min ) of the filter layer thickness is 2.0 or less. The shaped adsorbent described. The molded adsorbent according to any one of claims 1 to 5, wherein the molded adsorbent is produced by wet molding. A method for producing a molded adsorbent, which contains activated carbon and a fibrous binder, and has two or more through-holes penetrating in the longitudinal direction inside the molded adsorbent,
A first step of preparing a material slurry by mixing activated carbon, a fibrous binder and water,
A second step of preparing a precursor by wet molding using two or more shaft members using the material slurry; and
A method of manufacturing a shaped adsorbent, comprising a third step of drying the precursor to obtain a shaped adsorbent. The method for producing a molded adsorbent according to claim 7, wherein in the second step, a groove extending in the longitudinal direction is formed on the surface of the precursor at the center between the axes of the adjacent shaft members. The method for producing a molded adsorbent according to claim 7 or 8, wherein, in the second step, the entire precursor is compressed.

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