JP7271051B2 - water filter body - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water purification filter body comprising a substrate activated carbon, a powdered adsorbent and a fibrillated fiber binder.

Activated carbon, which has adsorption performance due to its porous structure, is used as a main material in filter bodies attached to water purifiers and the like. For this type of filter body, for example, a water purification filter body is known in which a base material activated carbon composed of fibrous activated carbon and powdered activated carbon is integrated with a fibrillated fiber binder (see, for example, Patent Document 1). Since the fibrillated fiber binder entangles and integrates the fibrous activated carbon and the powdered activated carbon, the water purification filter body is excellent in durability and shape retention. In this type of filter body, as the substrate activated carbon, not only fibrous activated carbon and powdered activated carbon, but also granular activated carbon can be used.

In recent years, there has been a demand for high-performance water purifiers, and in order to more reliably remove foreign substances such as residual components and fine insolubles contained in drinking water such as tap water, various methods have been used to improve water purification filters. is being considered. For example, the adsorption performance can be easily improved by mixing a powdered adsorbent with finer particles in addition to powdered activated carbon or granular activated carbon to form a filter body.

However, in the water-purifying filter body, since the powdery adsorbent is extremely fine particles, fine particles derived from the adsorbent tend to flow out at the initial stage of water passage. Therefore, there is a demand for a water purification filter body that can reduce the outflow of fine powder when water is passed through it when using a fine adsorbent for improving adsorption performance.

JP 2016-22399 A

The present invention has been made in view of the above points, and provides a water purification filter body that can reduce the outflow of fine powder derived from the powdery adsorbent when water is passed through the filter body containing the powdery adsorbent. It is.

That is, a first invention is a filter body comprising a substrate activated carbon, a powdery adsorbent, and a fibrillated fiber binder, wherein the substrate activated carbon has an average particle size of 25 to 160 μm, and the powdery The adsorbent is at least one selected from zeolite having an average particle size of 3 to 8 μm and sodium titanate, and the weight ratio of the filter body is 0.5 to 30 parts by weight. 1 to 20 parts by weight of a paper strength enhancer containing a strength enhancer is added to 100 parts by weight of the powdery adsorbent , and the fine powder reduction rate is 85.1% or more. related to the body.

According to the water purification filter body according to the first invention, the filter body includes a substrate activated carbon, a powdery adsorbent, and a fibrillated fiber binder, and the average particle diameter of the substrate activated carbon is 25 to 160 μm. , the powdery adsorbent is at least one selected from zeolite and sodium titanate having an average particle size of 3 to 8 μm, and the weight ratio of the filter body is 0.5 to 30 parts by weight; 1 to 20 parts by weight of a paper strength enhancer containing a cationic wet paper strength enhancer is added to 100 parts by weight of the powdery adsorbent , and the fine powder reduction rate is 85.1% or more . The force-enhancing agent easily bonds with the powdered adsorbent, which can greatly reduce the outflow of fine powder derived from the powdered adsorbent when water is passed through it, and at the same time, it is possible to ensure moldability and obtain excellent adsorption performance. It becomes possible to appropriately remove the metal ions in the liquid.

It is a perspective view of the water-purifying filter body which concerns on one Embodiment of this invention. It is a schematic process drawing which shows the manufacturing process of a water-purifying filter body.

The water-purifying filter body of the present invention is a filter for purifying liquid such as tap water, which contains a substrate activated carbon, a powdery adsorbent, and a fibrillated fiber binder, and is added with a paper strength agent. Become.

The base material activated carbon is activated carbon obtained by heating and sintering petroleum pitch, resin particles, trees, coconut shells, old tires, etc. at 800 to 1000° C., appropriately activating them to develop pores, and pulverizing them. The base activated carbon has the adsorption performance of general activated carbon required for water purification. Specifically, it satisfies iodine adsorption performance of 1000 to 2000 mg/g in the measurement based on JIS K 1474 (2014).

The base activated carbon is the main raw material that constitutes the filter body, and powdery activated carbon or granular activated carbon is used. By using powdered activated carbon or granular activated carbon as the base material activated carbon, the surface area per unit weight can be increased, and the filtration ability can be enhanced. The base activated carbon, which is powdery activated carbon or granular activated carbon, has an average particle size of 25 to 160 μm by classification or sieving from the viewpoint of adsorption performance and moldability. If the average particle size of the base material activated carbon is less than 25 μm, it becomes difficult to mold the filter body, and problems such as clogging due to an increase in dynamic water pressure during water flow occur. Further, when the average particle size of the substrate activated carbon is larger than 160 μm, as the particle size increases, the fine particle collection efficiency decreases, and the surface area of the activated carbon decreases, resulting in a decrease in adsorption performance. For the measurement of the average particle size, the particle size at an integrated value of 50% in the particle size distribution obtained by the laser diffraction/scattering method using a laser diffraction particle size distribution analyzer (SALD-3000S manufactured by Shimadzu Corporation) is adopted. bottom.

The powdery adsorbent is a powdery material having adsorption performance, and is composed of finer particles than the base material activated carbon, thereby improving the adsorption performance of the filter body. The powdery adsorbent has an average particle size of 3 to 20 μm. When the average particle size of the powdery adsorbent is less than 3 μm, the particle size becomes too small and tends to flow out from the water purification filter body. Further, when the average particle diameter of the powdery adsorbent is larger than 20 μm, the advantages of finer particles than the base activated carbon are lost, making it difficult to sufficiently improve the adsorption performance.

The material used in the powdery adsorbent is at least one selected from activated carbon, zeolite, titanium silicate or sodium titanate. Since activated carbon has excellent physical adsorption performance, it is possible to easily improve the adsorption performance of fine particles, etc. by forming it into a finer particle size than the base material activated carbon, which is the main raw material of the filter body, and adding it. . In addition, zeolite, titanium silicate, and sodium titanate are excellent in chemical adsorption performance, so they can adsorb metal ions in liquid. Therefore, it is possible to appropriately remove metal ions such as soluble lead.

The weight ratio of the powdery adsorbent to the filter body is set to 0.5 to 30 parts by weight from the viewpoint of adsorption performance and moldability. When the weight ratio of the powdery adsorbent is less than 0.5 parts by weight, it becomes difficult to exhibit sufficient adsorption performance by the powdery adsorbent. If the weight ratio of the powdery adsorbent is more than 30 parts by weight, moldability will be poor.

The fibrillated fiber binder is a material obtained by fluffing (fibrillating) synthetic resin fibers such as acrylic fibers, aramid fibers, and polyethylene fibers. In the fibrillated fiber binder, the base material activated carbon and the powdery adsorbent are entwined and integrated by fibrillating the fibers. Since the binder resin is excellent in durability and chemical resistance, it is possible to extend the service life of the filter body.

A paper strength agent is a chemical for retaining the powdered adsorbent. It is believed that the paper strength agent is held by hydrogen bonding with the powdery adsorbent. As paper strength agents, wet paper strength agents such as polyamide polyamine epichlorohydrin resins, melamine formaldehyde resins, and urea formaldehyde resins having water resistance are preferably used. In particular, it is more preferable to contain a cationic wet paper strength enhancer such as polyamide polyamine epichlorohydrin resin. The positively charged cationic wet paper strength agent is more likely to bond with the powdery adsorbent.

The paper strength agent is added in an amount of 1 to 20 parts by weight per 100 parts by weight of the powdery adsorbent from the viewpoint of moldability and difficulty in generating fine powder. If the amount of the paper strength agent added is less than 1 part by weight with respect to 100 parts by weight of the powdery adsorbent, it becomes difficult to sufficiently retain the powdery adsorbent. If the amount of the paper strength agent to be added is more than 20 parts by weight per 100 parts by weight of the powdery adsorbent, the shape retention of the filter body deteriorates, making it difficult to mold.

The shape of this filter body is not particularly limited and is suitable. For example, like the water purification filter body 10 shown in FIG. The hollow cylindrical member 11 is a core material having appropriate permeation holes, and may be left or removed depending on the application. From the viewpoint of shape retention of the filter body 10 , it is preferable that the hollow tubular member 11 remains inside the filter body 10 .

This tubular structure is a form that allows the surface area to be used most effectively when water is passed through and allows the liquid to pass through evenly. The surface of the water purification filter body 10 is covered and protected by a highly permeable cloth-like material 13 such as a non-woven fabric, as shown in FIG. 1(b), when sold or used. In FIG. 1(b), reference numeral 14 denotes a cap that protects the top and bottom of the filter body 10. As shown in FIG.

This water purifying filter body is suitably used, for example, as a filtering material for a water purifier. The water purification filter body loaded as a filter medium in the water purifier is preferably of a cartridge type so as to be easily replaceable. Cartridge-type water purifying filter bodies can be applied not only to domestic water purifiers, but also to stationary types and large-sized devices with enhanced filtering capacity.

Next, the manufacturing process of the water purification filter body will be described with reference to FIG. In this figure, reference numeral 20 is a filter body manufacturing apparatus, 21 is a water tank filled with water W, 22 is a stainless steel mold rod-shaped member in which a large number of pores are formed, and 25 is a dryer.

First, base activated carbon 31, which is powdered activated carbon or granular activated carbon, powdered adsorbent 32, fibrillated fiber binder 33, and paper strength agent 34 are prepared. These are put into the water W filled in the water tank 21 and sufficiently mixed to prepare the mixed slurry 30 .

Next, the mold rod-shaped member 22 is inserted into the hollow cylindrical member 11, and the integrated product 23 of the hollow cylindrical member 11 and the mold rod-shaped member 22 is put into the water tank 21 filled with the mixed slurry 30. be. Then, the mixed slurry-like material 30 is drawn to the side surface of the hollow cylindrical member 11 by vacuum suction through the mold rod-shaped member 22 in the water tank 21 . A non-woven fabric or the like may be wrapped around the hollow tubular member 11 as necessary.

Here, since the permeation holes of the non-woven fabric wrapped around the hollow cylindrical member 11 are smaller than those of the substrate activated carbon, the powdered adsorbent, etc., only the water content of the mixed slurry 30 passes through the hollow cylindrical member 11 and the gold is removed. The component 36 of the filter medium 12 remains on the surface of the hollow cylindrical member 11 because it is sucked out from the mold rod-shaped member 22 and the substrate activated carbon, powdered adsorbent, etc. cannot pass through. In this way, the component 36 of the filter medium 12 is accumulated on the surface of the hollow cylindrical member 11 to a predetermined thickness as the slurry-adhering portion 37, and the suction of the mixed slurry-like material 30 is terminated.

After a predetermined amount of slurry adhered portion 37 is formed, the hollow cylindrical member 11 is lifted out of the water tank 21, and the mold bar member 22 is removed. In this way, the adsorption adherend 35 having the slurry adherence portion 37 on the surface of the hollow cylindrical member 11 is obtained. After that, the adsorbed material 35 is heated and dried in the dryer 25 to complete the water purification filter body.

Next, using multiple types of base material activated carbon and powdered adsorbent, changing the blending ratio of the paper strength agent, etc., and mixing the fibrillated fiber binder, water purification of Prototype Examples 1 to 19 and Comparative Examples 1 to 12 A filter body was produced.

[Materials used]
<Base activated carbon>
The base activated carbon is activated carbon 1 with an average particle size of 20 μm (“CN20MS” manufactured by Futamura Chemical Co., Ltd.), activated carbon 2 with an average particle size of 29 μm (“CN30MS” manufactured by Futamura Chemical Co., Ltd.), and activated carbon 3 with an average particle size of 98 μm (Futamura "CN100MS" manufactured by Kagaku Co., Ltd.), activated carbon 4 with an average particle size of 158 μm ("CN8200S" manufactured by Futamura Chemical Co., Ltd.), or activated carbon 5 with an average particle size of 220 μm ("CN480S" manufactured by Futamura Chemical Co., Ltd.). . The average particle size of each base activated carbon was prepared by sieving.

<Powder Adsorbent>
The powdery adsorbent includes activated carbon with an average particle size of 20 μm (“CB” manufactured by Futamura Chemical Co., Ltd.), sodium trititanate with an average particle size of 3 μm (“Sodium trititanate” manufactured by Futamura Chemical Co., Ltd.), and an average particle size of 8 μm. Zeolite (“Zeolam (registered trademark) F-9 powder 100” manufactured by Tosoh Corporation) or titanium silicate with an average particle size of 12 μm (“ATS” manufactured by BASF Japan Ltd.) was used. The average particle size of each powdery adsorbent was prepared by sieving.

<Fibrillated fiber binder, paper strength agent>
As the fibrillated fiber binder, acrylic fiber (“Vipal (registered trademark)” manufactured by Toyobo Co., Ltd.) was used. The paper strength agent is a cationic wet paper strength agent, polyamide polyamine wet paper strength agent (“Arafix 255LOX” manufactured by Arakawa Chemical Industries, Ltd.), an anionic dry paper strength agent (Arakawa Chemical Industries, Ltd. ("Polystron 145") was used.

[Preparation of water purification filter body]
The substrate activated carbon, the powdered adsorbent, the fibrillated fiber binder, and the paper strength agent are dispersed in water according to the formulation (unit: parts by weight) described below, and thoroughly mixed in water until homogeneous. and mixed slurries corresponding to Comparative Examples 1 to 12 were prepared. The amount of water in the mixed slurry was 50 times the weight of the added solids. A hollow cylindrical member made of polypropylene having an inner diameter of 20 mm, an outer diameter of 24 mm, a total length of 50 mm, and pores with a diameter of 2 mm was prepared. A non-woven fabric was wrapped around the outer surface of the hollow cylindrical member. A porous stainless steel mold rod-shaped member is inserted and fixed in the hollow cylindrical member, and it is put into the mixed slurry, and the mixed slurry is sucked under reduced pressure (suction pressure is about -0.08 MPa). The solid content was drawn from the inside, and about 10.5 mm of the filter medium component was applied to the surface of the hollow cylindrical member (slurry-applied portion). The mold rod-shaped member was removed from the hollow cylindrical member to obtain an adsorbed adherent as an integrated product of the slurry adhered portion and the hollow cylindrical member. Then, using a dryer, the adsorbed adherent was heated and dried at 100° C. for 12 hours to prepare a purification filter body of a prototype example. The size of each filter body is a cylindrical body with a diameter of 45 mm and a total length of 50 mm, including a hollow cylindrical member. The surface of the filter body was covered with a non-woven fabric made of mixed fibers of polyethylene and polypropylene, and caps made of polypropylene were attached to the top and bottom of the filter body.

[Evaluation item]
Regarding the water purification filter bodies of Prototype Examples 1 to 19, the comparison of the content of the paper strength enhancer, the comparison of the types of the strength enhancer, the comparison of the particle size of the base activated carbon, and the type of powdered adsorbent are as follows. and the content of the powdery adsorbent were evaluated according to the fine powder reduction performance test, the free residual salt removal performance test, and the soluble lead removal performance test, respectively, and the quality was examined.

<Fine powder reduction performance test>
In order to evaluate fine powder reduction performance, tests were conducted using filter bodies (Comparative Examples 1 to 12) to which no paper strength agent was added as a reference. In this test, the water flow rate was set to 2.0 L/min, and 200 mL of water was sampled at the initial stage of water flow for measurement. Measurement was performed using a photoelectric spectrophotometer with a measurement wavelength of 660 nm and a 100 mm cell. The fine powder reduction rate of each prototype example 1 to 19 was calculated based on the absorbance value of the filter body (Comparative Examples 1 to 12) to which the paper strength agent was not added (fine powder reduction rate (%) = (1 - of the prototype example absorbance value/absorbance value of comparative example)×100). In calculating the fine powder reduction rate, Prototype Examples 1 to 8 are based on Comparative Example 1, Prototype Example 9 is Comparative Example 2, Prototype Example 10 is Comparative Example 3, Prototype Example 11 is Comparative Example 4, and Prototype Example 12 is Comparative Example. 5, Prototype Example 13 is Comparative Example 6, Prototype Example 14 is Comparative Example 7, Prototype Example 15 is Comparative Example 8, Prototype Example 16 is Comparative Example 9, Prototype Example 17 is Comparative Example 10, Prototype Example 18 is Comparative Example 11, Prototype Example 19 was obtained based on Comparative Example 12, respectively. In the evaluation of the fine powder reduction performance, the fine powder reduction rate of less than 40% was evaluated as "x", which is a defective product. In addition, 40% or more was defined as a passing point, and 50% or more was defined as a more preferable state. Therefore, an absorbance of 40% or more and less than 50% was evaluated as "Δ", and an absorbance of 50% or more was evaluated as "Good".

<Free residual chlorine removal performance test>
In order to evaluate the free residual chlorine removal performance, a test was conducted in accordance with JIS S 3201 (2010), a test method for household water purifiers. In this test, the free residual chlorine concentration was set to 2 mg/L and the water flow rate was set to 2.0 L/min, and the free residual chlorine removal rate was measured after continuous water flow for 10 minutes. In the evaluation, when the removal rate was less than 95%, it was rated as "poor", and when it was 95% or more, it was rated as "good".

<Soluble lead removal performance test>
In order to evaluate the metal ion removal performance, a test was conducted in accordance with JIS S 3201 (2010), a test method for household water purifiers. In this test, the concentration of soluble lead was set to 50 μg/L and the water flow rate was set to 2.0 L/min, and the removal rate of soluble lead after continuous water flow for 10 minutes was measured. In the evaluation, when the removal rate was less than 95%, it was rated as "poor", and when it was 95% or more, it was rated as "good".

[Comparison of paper strength agent content]
A filter body (paper strength enhancer was not added) was used as Comparative Example 1. Then, a paper strength enhancer (polyamide polyamine wet paper strength enhancer, hereinafter the same) was added to the composition of Comparative Example 1 in different amounts to obtain Prototype Examples 1 to 6.

In Tables 1 and 2 below, the amount of the paper strength enhancer added is expressed as a weight ratio with respect to 100 parts by weight of the powdery adsorbent. That is, the added amount of the paper strength agent in Prototype Example 1 is 0.5 parts by weight with respect to 100 parts by weight of the powdery adsorbent (0.05 parts by weight with respect to 10 parts by weight of the powdery adsorbent shown in the table). , The amount of the paper strength agent added in Prototype Example 2 is 1.0 parts by weight with respect to 100 parts by weight of the powdery adsorbent (0.1 parts by weight with respect to 10 parts by weight of the powdery adsorbent shown in the table), The amount of the paper strength agent added in Prototype Example 3 was 2.0 parts by weight with respect to 100 parts by weight of the powdered adsorbent (0.2 parts by weight with respect to 10 parts by weight of the powdered adsorbent shown in the table). The amount of the paper strength enhancer in Example 4 is 10 parts by weight with respect to 100 parts by weight of the powdery adsorbent (1 part by weight with respect to 10 parts by weight of the powdery adsorbent shown in the table), and the paper strength of Prototype Example 5 The amount of the reinforcing agent added is 20 parts by weight with respect to 100 parts by weight of the powdery adsorbent (2 parts by weight with respect to 10 parts by weight of the powdery adsorbent shown in the table), and the amount of the paper strength enhancer of Prototype Example 5. is 30 parts by weight with respect to 100 parts by weight of the powdered adsorbent (3 parts by weight with respect to 10 parts by weight of the powdered adsorbent shown in the table).

[Results and discussion of comparison of paper strength agent content]
As shown in Tables 1 and 2, in Prototype Example 6, the shape could not be properly maintained and could not be molded in the production of the filter body. In the other Prototype Examples 1 to 5, the molding of the filter body was good. In Prototype Example 6, the paper strength enhancer was added in excess (30 parts by weight) compared to other Prototype Examples 1 to 5. Therefore, as a condition for obtaining sufficient moldability of the filter body, the paper strength enhancer is considered to be preferably 20 parts by weight or less. In Prototype Example 6, since the filter body could not be molded, the fine powder reduction performance test, the free residual chlorine removal performance test, and the soluble lead removal performance test were not performed.

Good results were obtained in both the free residual chlorine removal performance test and the soluble lead removal performance test for Prototype Examples 1 to 5. In the fine powder reduction performance test, the fine powder reduction rate (absorbance) was 44.4% in Prototype Example 1, and the fine powder reduction rate was 70% or higher in Prototype Examples 2 to 5. Since a fine powder reduction rate of 50% or more is a good product, as shown in Prototype Examples 2 to 5, it is considered that 1.0 parts by weight or more of the paper strength enhancer is preferable as a condition for obtaining good fine powder reduction performance. Therefore, it was found that the appropriate content of the paper strength agent is 1 to 20 parts by weight based on the conditions for moldability of the filter body and the conditions for fine powder reduction performance.

[Comparison of types of paper strength agents]
In the composition of Comparative Example 1, 1.0 parts by weight of an anionic dry paper strength agent is added to 100 parts by weight of the powdery adsorbent (0.1 parts by weight for 10 parts by weight of the powdery adsorbent shown in the table). ) was added to the filter body in Prototype Example 7, and the cationic wet paper strength agent (polyamide polyamine wet paper strength agent) was 1.0 parts by weight with respect to 100 parts by weight of the powdery adsorbent (powder adsorption shown in the table 0.1 parts by weight for 10 parts by weight of material) and 0.5 parts by weight for 100 parts by weight of powdered adsorbent (10 parts by weight of powdered adsorbent shown in the table) and an anionic dry paper strength agent 0.05 parts by weight) was mixed and added as Prototype Example 8. In Table 3 below, Comparative Example 1 in which no paper strength enhancer is added, 1.0 wt. Parts (0.1 parts by weight for 10 parts by weight of the powdery adsorbent shown in the table) were added in Prototype Example 2, respectively.

[Results and discussion of comparison of types of paper strength agents]
As shown in Table 3, in Prototype Example 7 in which an anionic dry paper strength enhancer was used alone as a paper strength enhancer, the fine powder reduction rate was insufficient. On the other hand, Prototype Example 2 using a cationic wet strength agent alone as a paper strength agent, or a trial example using a mixture of a cationic wet strength agent and an anionic dry strength agent In No. 8, the fine powder reduction rate was good. From this, it was found that by using a cationic wet paper strength agent as the main paper strength agent, a good fine powder reduction performance can be obtained.

[Comparison of particle size of substrate activated carbon]
Comparative Example 2 is a filter body composed of 90 parts by weight of activated carbon 1 having an average particle size of 20 μm as a base activated carbon and the same formulation as in Comparative Example 1 except for this. A filter body to which 1.0 parts by weight of a wet paper strength enhancer (the same applies hereinafter) is added to 100 parts by weight of the powdery adsorbent (0.1 parts by weight for 10 parts by weight of the powdery adsorbent shown in the table) was taken as Prototype Example 9. A filter body composed of 90 parts by weight of activated carbon 2 having an average particle diameter of 29 μm as the base activated carbon and the same composition as in Comparative Example 1 was used as Comparative Example 3. Prototype Example 10 was prepared by adding 1.0 part by weight to 100 parts by weight of the material (0.1 part by weight to 10 parts by weight of the powdery adsorbent shown in the table). A filter body composed of 90 parts by weight of activated carbon 4 having an average particle size of 158 μm as a base activated carbon and the same composition as in Comparative Example 1 was used as Comparative Example 4, and a paper strength agent was added to the composition of Comparative Example 4 to adsorb powder. Prototype Example 11 was a filter body in which 1.0 part by weight was added to 100 parts by weight of the material (0.1 part by weight to 10 parts by weight of the powdery adsorbent shown in the table). 90 parts by weight of activated carbon 5 having an average particle size of 220 μm as the base material activated carbon, and the filter body having the same composition as in Comparative Example 1 except for this is designated as Comparative Example 5, and the composition of Comparative Example 5 is added with a paper strength agent for powder adsorption Prototype Example 12 was prepared by adding 1.0 part by weight to 100 parts by weight of the material (0.1 part by weight to 10 parts by weight of the powdery adsorbent shown in the table). Table 4 below also lists Comparative Example 1 and Prototype Example 2 using activated carbon 3 having an average particle size of 98 μm as the base activated carbon.

[Results and Discussion of Comparison of Particle Size of Base Activated Carbon]
As shown in Tables 4 and 5, in Comparative Example 2 and Prototype Example 9, the shape could not be properly maintained during the production of the filter body, and the molding could not be performed. In other Comparative Examples 1, 3 to 5 and Prototype Examples 2, 10 to 12, the molding of the filter body was good. In Comparative Example 2 and Prototype Example 9, compared with other Comparative Examples 1, 3 to 5 and Prototype Examples 2, 9 to 12, the average particle size of the base material activated carbon is finer (20 μm). As a condition for obtaining good moldability, the average particle size of the substrate activated carbon is considered to be preferably 25 μm or more. In Prototype Example 9, since the filter body could not be molded, the fine powder reduction performance test, free residual chlorine removal performance test, and soluble lead removal performance test were not performed.

Good results were obtained in both the free residual chlorine removal performance test and the soluble lead removal performance test for Prototype Examples 10 to 12. Further, in the fine powder reduction performance test, Prototype Example 12 had a fine powder reduction rate of 43.2%, and Prototype Examples 10 and 11 both had high fine powder reduction rates of 60% or more. Since a fine powder reduction rate of 50% or more is a good product, as shown in Prototype Examples 2, 10, and 11, the average particle size of the base activated carbon is considered to be 160 μm or less as a condition for obtaining good fine powder reduction performance. Therefore, it was found that the appropriate average particle size of the base material activated carbon is 25 to 160 μm, based on the filter body moldability conditions and the fine powder reduction performance conditions.

[Comparison of types of powdery adsorbents]
10 parts by weight of activated carbon having an average particle size of 20 μm as a powdery adsorbent, and a filter body composed of the same formulation as in Comparative Example 1 except for this was used as Comparative Example 6. A filter body to which 1.0 parts by weight of a wet paper strength enhancer (the same applies hereinafter) is added to 100 parts by weight of the powdery adsorbent (0.1 parts by weight for 10 parts by weight of the powdery adsorbent shown in the table) was taken as Prototype Example 13. Comparative Example 7 is a filter body composed of 10 parts by weight of sodium trititanate having an average particle size of 3 μm as a powdery adsorbent and the same composition as in Comparative Example 1 except for this, and a paper strength agent is added to the composition of Comparative Example 7. A filter body in which 1.0 part by weight was added to 100 parts by weight of the powdery adsorbent (0.1 part by weight to 10 parts by weight of the powdered adsorbent shown in the table) was used as Prototype Example 14. A filter body composed of 10 parts by weight of zeolite having an average particle diameter of 8 μm as a powdery adsorbent and the same composition as in Comparative Example 1 except for this was used as Comparative Example 8, and a paper strength agent was added to the composition of Comparative Example 8 for powdery adsorption. Prototype Example 15 was prepared by adding 1.0 part by weight to 100 parts by weight of the material (0.1 part by weight to 10 parts by weight of the powdery adsorbent shown in the table). Table 7 below also lists Comparative Example 1 and Prototype Example 2 using titanium silicate having an average particle size of 12 μm as the powdery adsorbent.

[Results and Discussion of Comparison of Types of Powdery Adsorbents]
As shown in Tables 6 and 7, in Prototype Example 13, the soluble lead removal performance test was not performed, and good results were obtained in both the fine powder reduction performance test and the free residual chlorine removal performance test. Prototype Example 13 can be appropriately used as a water purification filter body because the generation of fine powder is reduced and the adsorption performance is excellent. Moreover, in Prototype Examples 2, 14, and 15, good results were obtained in all of the soluble lead removal performance test, the fine powder reduction performance test, and the free residual chlorine removal performance test. Therefore, it was found that any of activated carbon, sodium trititanate, zeolite, and titanium silicate can be suitably used as the powdery adsorbent.

[Comparison of content of powdery adsorbent]
A filter body ( Comparative Example 9 was prepared without adding a paper strength agent. In the formulation of Comparative Example 9, 1.0 parts by weight of a paper strength agent (polyamide polyamine wet paper strength agent, hereinafter the same) was added to 100 parts by weight of the powdery adsorbent (0.1 part by weight of the powdery adsorbent shown in the table). 0.001 part by weight) was added as Prototype Example 16.

A filter body ( Comparative Example 10 (no paper strength agent added). 1.0 parts by weight of a paper strength agent per 100 parts by weight of the powdery adsorbent (0.005 parts by weight with respect to 0.5 parts by weight of the powdered adsorbent shown in the table) was added to the composition of Comparative Example 10. The resulting filter body was referred to as Prototype Example 17.

A filter body (paper strength enhancer was not added) was used as Comparative Example 11. A filter in which 1.0 parts by weight of a paper strength agent was added to the composition of Comparative Example 11 with respect to 100 parts by weight of the powdered adsorbent (0.3 parts by weight with respect to 30 parts by weight of the powdered adsorbent shown in the table) The body was designated as Prototype Example 18.

A filter body (paper strength enhancer was not added) was used as Comparative Example 12. A filter in which 1.0 parts by weight of a paper strength agent was added to the composition of Comparative Example 12 with respect to 100 parts by weight of the powdered adsorbent (0.4 parts by weight with respect to 40 parts by weight of the powdered adsorbent shown in the table) The body was designated as Prototype Example 19. Table 8 below also lists Comparative Example 1 and Prototype Example 2 in which the substrate activated carbon was 90 parts by weight and the powdery adsorbent was 10 parts by weight.

[Results and Considerations of Comparison of Contents of Powdery Adsorbents]
As shown in Tables 8 and 9, in Comparative Example 12 and Prototype Example 19, the shape could not be properly maintained during the production of the filter body, and molding could not be performed. In other Comparative Examples 1, 9 to 11 and Prototype Examples 2, 16 to 18, the molding of the filter body was good. In Comparative Example 12 and Prototype Example 19, the content of the powdery adsorbent is excessive (40 parts by weight) compared to other Comparative Examples 1, 9 to 11 and Prototype Examples 2, 16 to 18, so the filter As a condition for obtaining sufficient formability of the body, it is considered preferable that the content of the powdery adsorbent is 30 parts by weight or less. In Prototype Example 19, since the filter body could not be molded, the fine powder reduction performance test, free residual chlorine removal performance test, and soluble lead removal performance test were not performed.

Good results were obtained in both the fine powder reduction performance test and the free residual chlorine removal performance test for Prototype Examples 2 and 16 to 18. Regarding the soluble lead removal performance test, the soluble lead removal rate was 92.8% in Prototype Example 16, but did not reach the desired performance. In Prototype Examples 2, 17, and 18, good results were obtained. In Prototype Example 16, the amount of the powdery adsorbent is very small (0.1 parts by weight) compared to other Prototype Examples 2, 17, and 18. It is considered that the content of the adsorbent is preferably 0.5 parts by weight or more. Therefore, it was found that the appropriate content of the powdery adsorbent is 0.5 to 30 parts by weight, based on the conditions of moldability of the filter body and the conditions of soluble lead removal performance.

The water purification filter body of the present invention contains a powdered adsorbent to improve adsorption performance, and the paper strength enhancer reduces the outflow of fine powder derived from the powdered adsorbent. The occurrence of defects is reduced. Therefore, it is promising as a substitute for conventional water purification filter bodies.

REFERENCE SIGNS LIST 10 Water purification filter body 11 Hollow cylinder member 12 Filter medium 13 Cloth material 14 Cap 20 Filter body manufacturing apparatus 21 Water tank 22 Mold rod member 23 Hollow cylinder member and mold rod member integrated 25 Dryer 30 Mixed slurry material 31 Base activated carbon 32 Powdered adsorbent 33 Fibrillated fiber binder 34 Paper strength agent 35 Adsorbed material 36 Components of filter medium part 37 Slurry adhered part W Water

Claims (1)

A filter body comprising a substrate activated carbon, a powdered adsorbent, and a fibrillated fiber binder,
The average particle size of the base material activated carbon is 25 to 160 μm,
The powdery adsorbent is at least one selected from zeolite and sodium titanate having an average particle size of 3 to 8 μm, and the weight ratio of the filter body is 0.5 to 30 parts by weight,
1 to 20 parts by weight of a paper strength enhancer containing a cationic wet paper strength enhancer is added to 100 parts by weight of the powdery adsorbent,
Fine powder reduction rate is 85.1% or more
A water purification filter body characterized by:

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