adsorptive filter

Abstract

The present application relates to an adsorption filter including a molded body containing activated carbon and a binder, and having a pore volume of 0.06 cm 3 / cc or more and 0.30 cm 3 / cc or less of pores having a pore diameter of 15 μm or more and 30 μm or less, as measured by a mercury porosimetry method. The present application relates to an adsorption filter including a molded body containing activated carbon and a binder, and having a pore volume of 0.06 cm 3 / cc or more and 0.30 cm 3 / cc or less of pores having a pore diameter of 15 μm or more and 30 μm or less, as measured by a mercury porosimetry method.

Description

Technical Field

[0001] The present invention relates to an adsorption filter comprising a molded body containing activated carbon and a binder. Background Technology

[0002] In recent years, there has been increasing concern about the safety and hygiene of tap water, with the expectation of removing harmful substances such as free residual chlorine, trihalomethanes and other VOCs (volatile organic compounds), pesticides, and musty odors from tap water.

[0003] To remove this harmful substance, an adsorption filter, which includes an activated carbon mold, is typically used.

[0004] It is desirable that adsorption filters including activated carbon molded bodies also possess the ability to remove turbidity components (particulate matter) contained in tap water. To this end, for example, Patent Document 1 discloses a method for manufacturing a filter body that enables turbidity reduction over a longer period by adjusting the hardness difference between the inflow and outflow filter material portions of the activated carbon molded body. Furthermore, for example, Patent Document 2 discloses a water purification filter cartridge comprising an activated carbon molded body and non-woven fabric, which achieves both high turbidity removal performance and a sufficiently long clogging life. Furthermore, for example, Patent Document 3 discloses an activated carbon molded body formed from a mixture comprising powdered activated carbon (a) with a central particle size of 80 μm to 120 μm and a standard deviation σg of 1.3 to 1.9 in the particle size distribution, and a fibrous binder (b). According to the activated carbon molded body of Patent Document 3, it is described as exhibiting excellent removal capabilities for free residual chlorine, volatile organic compounds, CAT, and 2-MIB, as well as excellent turbidity filtration capabilities.

[0005] Generally, the turbidity removal performance test for activated carbon molded filters is specified in, for example, JIS S 3201:2019. In this test, kaolinite with a particle size of approximately 1 μm to 20 μm is used as the turbidity component (particulate matter), and its removal performance is evaluated. The turbidity removal performance of activated carbon molded filters in Patent Documents 1, 2, and 3 is also evaluated based on this test.

[0006] On the other hand, recently, from a further safety and hygiene perspective, there has been a demand for adsorption filters, including molded activated carbon bodies, to not only remove microparticles (generally with a particle size of 1 μm to 20 μm) but also to remove ultrafine particles with a particle size of 1 μm or less. For example, Patent Document 4 describes a molded adsorbent body that improves microparticle removal performance by specifying the central particle size D50 of the particulate matter and the content of particulate matter with a particle size of 10 μm or less within a specified range.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Publication No. 2015-033680

[0010] Patent Document 2: Japanese Patent Publication No. 2016-140788

[0011] Patent Document 3: International Publication No. 2011 / 016548

[0012] Patent Document 4: Japanese Patent Publication No. 2021-122778 Summary of the Invention

[0013] The purpose of this invention is to provide an adsorption filter that can simultaneously achieve excellent water permeability and ultrafine particle removal performance based on low water flow resistance, and can be used for a long time.

[0014] The inventors conducted dedicated research to solve the above-mentioned problems, and as a result, the present invention was realized.

[0015] The first aspect of the present invention relates to an adsorption filter comprising a molded body containing activated carbon and a binder, wherein,

[0016] The volumetric pore volume of the adsorption filter, determined using mercury porosimetry, is 0.06 cm³, with a pore diameter of 15 μm or more and 30 μm or less. 3 / cc~0.30cm 3 / cc.

[0017] Alternatively, the second aspect of the invention relates to an adsorption filter comprising a molded body containing activated carbon and a binder, wherein,

[0018] In the cumulative particle size distribution of the activated carbon based on volume, D50 is 30 μm or more and 110 μm or less, D90 is 110 μm or more, and...

[0019] The activated carbon has a particle size of less than 10 μm and a particle content of more than 1.2% by volume and less than 8.9% by volume. Attached Figure Description

[0020] Figure 1 A perspective view is shown, illustrating an example of a template used to prepare the adsorption filter of this embodiment.

[0021] Figure 2 It means to use Figure 1 A perspective view of an example of an adsorption filter of this embodiment obtained from the template.

[0022] Figure 3 This is a diagram illustrating the sample cutting method when determining the pore volume of an adsorption filter.

[0023] Figure 4 This is a perspective view showing an example of an automatic grinding machine used to manufacture adsorption filters.

[0024] Figure 5 This is a graph showing the results of water flow tests conducted using test water containing turbid substances in Examples 1-3 and Comparative Example 1.

[0025] Figure 6 This is a graph showing the results of water flow tests using test water containing turbid substances during backwashing operations in Examples 1-3 and Comparative Example 1.

[0026] Figure 7 This is a graph showing the results of water flow tests conducted using test water containing turbid substances in Examples 4-6.

[0027] Figure 8 This is a graph showing the results of a water flow test using test water containing turbid substances during backwashing operations in Examples 4-6.

[0028] Figure 9 This is a graph showing the results of water flow tests conducted using test water containing turbid substances in Comparative Examples 2-5.

[0029] Figure 10 This is a graph showing the results of a water flow test using test water containing turbid substances during backwashing operations in Comparative Examples 2-5. Detailed Implementation

[0030] As described above, the shaped adsorbent described in Patent Document 4 improves particulate removal performance by specifying the central particle size D50 of the particulate matter and the content of particulate matter with a particle size of 10 μm or less within a specified range. However, to improve the particulate removal performance of an adsorption filter, especially the removal performance of ultrafine particles, it is generally necessary to reduce the porosity of the adsorption filter by making the particle size of the raw material activated carbon finer. Therefore, the water flow resistance of the adsorption filter will increase. Therefore, there is a need for an adsorption filter that can simultaneously achieve excellent water flow and ultrafine particle removal performance based on low water flow resistance.

[0031] Furthermore, it is believed that adsorption filters using finely sized activated carbon particles, such as those described in Patent Document 4, are more prone to clogging due to turbid substances of approximately 1 μm to 20 μm. As a result, the removal performance of the adsorption filter is estimated to decrease, and the lifespan of the adsorption filter is shortened.

[0032] To extend the life of an adsorption filter, a method is employed that involves reversing the water flow direction at specified intervals (referred to as "backwashing" in this specification) to eliminate clogging caused by turbid substances. However, even with this backwashing, it is estimated that adsorption filters containing finely sized activated carbon may struggle to release turbid substances.

[0033] According to the present invention, an adsorption filter can be provided that simultaneously achieves excellent flowability and ultrafine particle removal performance based on low water resistance, and can be used for a long period of time. The adsorption filter of the present invention can effectively regenerate the flow rate through backwashing, and can extend the filter's lifespan.

[0034] The embodiments of the present invention will be described in detail below. It should be noted that the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without prejudice to the spirit of the present invention.

[0035] The adsorption filter of this embodiment is an adsorption filter comprising a molded body containing activated carbon and a binder, wherein the pore volume of the adsorption filter, measured using mercury porosimetry as a volume reference, is 0.06 cm³, with a pore diameter of 15 μm or more and 30 μm or less. 3 / cc~0.30cm 3 / cc.

[0036] Alternatively, the adsorption filter of this embodiment is an adsorption filter comprising a molded body containing activated carbon and a binder, wherein, in the cumulative particle size distribution of the activated carbon on a volume basis, D50 is 30 μm or more and 110 μm or less, D90 is 110 μm or more, and the content of activated carbon particles with a particle size of 10 μm or less is 1.2% by volume or more and 8.9% by volume or less.

[0037] It should be noted that, in this specification, "D50" refers to the 50% particle size in the cumulative particle size distribution on a volumetric basis. Furthermore, "D90" refers to the 90% particle size in the cumulative particle size distribution on a volumetric basis. Additionally, "D10," measured in the examples described later, refers to the 10% particle size in the cumulative particle size distribution on a volumetric basis.

[0038] The adsorption filter of this embodiment, by having any of these configurations, can simultaneously achieve excellent water permeability and ultrafine particle removal performance based on low water flow resistance, and can be used for a long time.

[0039] Specifically, in this embodiment, by appropriately selecting and / or adjusting the physical properties and proportions of the raw activated carbon, and appropriately controlling the pore volume in the filter, the pore volume within a specified pore diameter range is adjusted to be within a specific range. Alternatively, in this embodiment, activated carbon used as the raw material is activated carbon whose D50 and D90 in the cumulative particle size distribution based on volume are within a specified range, and whose content of particle size below a specific value is within a specified range. As a result, an adsorption filter that can simultaneously achieve excellent water permeability and ultrafine particle removal performance based on low water flow resistance and can be used for a long time can be obtained.

[0040] [Properties of Adsorption Filters]

[0041] Regarding the adsorption filter of this embodiment, the pore volume (hereinafter also referred to as "pore volume with a pore diameter of 15 μm or more and 30 μm or less"), measured using mercury porosimetry, is 0.06 cm³. 3 / cc~0.30cm 3 / cc. The pore volume is set to 0.06cm³ for pores with a diameter of 15μm or more but less than 30μm. 3 With a flow rate of 100 cc or higher, clogging caused by turbid substances is suppressed, resulting in an adsorption filter with excellent water permeability and long-term reliable operation. Furthermore, backwashing effectively regenerates the flow rate of the adsorption filter and extends its lifespan. Additionally, the pore volume is set to 0.30 cm³, with a pore diameter of 15 μm or more and 30 μm or less. 3 A particle size below / cc enables the adsorption filter to achieve good ultrafine particle removal performance.

[0042] The preferred pore volume is 0.08 cm³, where the pore diameter is 15 μm or more and 30 μm or less. 3 / cc or more, preferably 0.10cm 3 / cc or higher, further preferably 0.12cm 3 / cc or more, with 0.13cm being particularly preferred. 3 / cc or more. Furthermore, the pore volume is preferably 0.27 cm³, with a pore diameter of 15 μm or more and 30 μm or less. 3 / cc or less, preferably 0.25cm 3 Below / cc, 0.23cm is further preferred. 3 Below / cc, 0.21cm is particularly preferred. 3 / cc and below.

[0043] Furthermore, regarding the adsorption filter of this embodiment, the pore volume (hereinafter also simply referred to as "pore volume with a pore diameter of 7 μm or less") based on the volume reference of the adsorption filter determined by mercury porosimetry is preferably 0.10 cm³. 3 / cc or higher. The pore volume is set to 0.10 cm³ for pores with a diameter of 7μm or less. 3 With a particle size of 6cc or higher, adsorption filters can achieve significantly superior ultrafine particle removal performance.

[0044] The pore volume is more preferably 0.12 cm³ for pore diameters of 7 μm or less. 3 / cc or higher, further preferably 0.14cm 3 / cc or more. Furthermore, there is no particular upper limit to the pore volume for pores with a diameter of 7 μm or less; for example, a pore volume of 0.50 cm³ for pores with a diameter of 7 μm or less is preferably 0.50 cm³. 3 / cc or less, preferably 0.45cm 3 Below / cc, 0.40cm is further preferred. 3 / cc and below.

[0045] Furthermore, the adsorption filter of this embodiment preferably has a total pore volume (hereinafter also simply referred to as "total pore volume") based on the volume of the adsorption filter as determined by mercury porosimetry, preferably 0.50 cm³. 3 / cc~0.73cm 3 / cc. By setting the total pore volume to 0.50cm. 3 With a volume of / cc or higher, adsorption filters achieve superior water permeability, making them suitable for applications such as water purification filters. This is achieved by setting the total pore volume to 0.73 cm³. 3 With a capacity of less than / cc, it can maintain a sufficient amount of activated carbon, resulting in good adsorption performance as a general filter.

[0046] The total pore volume is more preferably 0.53 cm³. 3 / cc or higher, further preferably 0.56cm 3 / cc or higher. Furthermore, a total pore volume of 0.70 cm³ is more preferable. 3 Below / cc, 0.67cm is further preferred. 3 / cc and below.

[0047] In this specification, the pore volume with a pore diameter of 15 μm or more but less than 30 μm, the pore volume with a pore diameter of 7 μm or less, and the total pore volume, as described in the examples below, can be measured using a mercury porosimetry pore volume measuring device (MicroActive AutoPore V9620, manufactured by Micromeritics). It should be noted that in the examples below, a test sample of approximately 1 cm square of the filter's molded layer is used; however, it is preferable to appropriately change the size of the test sample according to the filter size. For example, if it is a faucet-mounted filter, a test sample of approximately 5 mm square is preferably used for measurement.

[0048] The pore volume of the adsorption filter of this embodiment, as described above, having a pore diameter of 15 μm or more and 30 μm or less, a pore volume of 7 μm or less, and a total pore volume, can be controlled by various methods. For example, these values ​​can be controlled by appropriately selecting and / or adjusting the physical properties and dosage of the raw activated carbon, the proportion of two or more activated carbons with different physical properties when using them, the type and dosage of the raw material binder, the dosage of any component of the raw material, and the processing conditions (suction pressure, drying time, etc.) during the manufacture of the adsorption filter. In particular, as detailed later, the pore volume with a pore diameter of 15 μm or more and 30 μm or less can be controlled by adjusting the D50 and D90 of the raw activated carbon and the particle content (volume %) of the raw activated carbon with a particle size of 10 μm or less within a specified range.

[0049] The density of the adsorption filter in this embodiment (hereinafter also simply referred to as "filter density") is preferably 0.59 g / cm³. 3 The following is an example of achieving a filter density of 0.59 g / cm³. 3 The following properties allow for better maintenance of water flow resistance, making it suitable for applications such as water purifiers. Furthermore, it helps prevent filter clogging. Additionally, a filter density of 0.35 g / cm³ is preferred. 3 The above. By making the filter density 0.35 g / cm³. 3 The above indicates that the total amount of activated carbon is suitable, which can effectively maintain the removal performance of ultrafine particles and other common harmful substances.

[0050] The filter density is more preferably 0.38 g / cm³. 3 The above is further preferred to be 0.40 g / cm³. 3 The above, especially preferred, is 0.42 g / cm³. 3 That's all. Furthermore, a filter density of 0.57 g / cm³ is more preferable. 3The following is a further preferred value: 0.55 g / cm³ 3 The following is particularly preferred: 0.53 g / cm³ 3 The filter density can be determined using the methods detailed in the examples described below.

[0051] Filter density can be controlled in various ways. For example, it can be controlled by appropriately selecting and / or adjusting the physical properties and dosage of the raw activated carbon, the proportion of two or more activated carbons with different physical properties when using them, the type and dosage of the raw material binder, the dosage of any component of the raw material, and the processing conditions (suction pressure, drying time, etc.) during the manufacture of the adsorption filter.

[0052] The benzene saturation adsorption capacity of the adsorption filter in this embodiment is preferably 18% to 35%. In this specification, the benzene saturation adsorption capacity of the adsorption filter can be determined by passing air containing 1 / 10 of the solvent saturation concentration through the activated carbon test method according to JIS K 1474:2014 at 25°C, and by measuring the weight gain (%) of the sample when the mass reaches a constant value.

[0053] By setting the benzene saturation adsorption capacity to 18% or higher, sufficient removal performance can be obtained, especially for organic matter. By setting the benzene saturation adsorption capacity to 35% or lower, it is possible to prevent the pore diameter from increasing in the overactivated state and to suppress the possibility of a decrease in the adsorption and retention capacity of harmful substances. The benzene saturation adsorption capacity is more preferably 20% or higher, and even more preferably 22% or higher. Furthermore, the benzene saturation adsorption capacity is more preferably 33% or lower, and even more preferably 30% or lower.

[0054] The benzene saturation adsorption capacity of the adsorption filter in this embodiment can be controlled, for example, by appropriately selecting and / or adjusting the physical properties of the raw material activated carbon and its proportion, or by adjusting the proportion of two or more types of activated carbon with different physical properties when using them.

[0055] [Structure of an adsorption filter]

[0056] The adsorption filter of this embodiment includes a molded body containing activated carbon and a binder.

[0057] (Activated carbon)

[0058] The activated carbon used as raw material in the adsorption filter of this embodiment has a cumulative particle size distribution on a volume basis, with a D50 of 30 μm or more and 110 μm or less, and a D90 of 110 μm or more. Furthermore, the content of particles with a particle size of 10 μm or less is 1.2% by volume or more and 8.9% by volume or less.

[0059] By using activated carbon of this particle size as a raw material, it is possible to obtain micropores with a diameter of 15 μm or more and less than 30 μm, and a pore volume of 0.06 cm³. 3 / cc~0.30cm 3 Adsorption filters within the range of / cc.

[0060] Specifically, by using activated carbon with a D50 of 30 μm or more and 110 μm or less, and a D90 of 110 μm or more as the raw material, the pore volume of the adsorption filter, with a pore diameter of 15 μm or more and 30 μm or less, can be increased. As a result, clogging caused by turbidity is suppressed, resulting in an adsorption filter with excellent water permeability and long-term reliable operation. Furthermore, backwashing effectively regenerates the flow rate and extends the lifespan of the adsorption filter.

[0061] In the raw activated carbon, the D50 is preferably 33 μm or more, more preferably 40 μm or more, even more preferably 44 μm or more, and particularly preferably 50 μm or more. Furthermore, in the raw activated carbon, the D50 is preferably 108 μm or less, more preferably 100 μm or less, even more preferably 92 μm or less, and particularly preferably 85 μm or less.

[0062] In the raw activated carbon, D90 is preferably 120 μm or more, more preferably 130 μm or more, even more preferably 140 μm or more, and particularly preferably 150 μm or more. Furthermore, there is no particular upper limit to D90; for example, 300 μm or less is acceptable.

[0063] Furthermore, by making the content of particles with a particle size of 10 μm or less in the raw activated carbon 1.2 vol% or more, an adsorption filter with excellent ultrafine particle removal performance can be obtained. Furthermore, by making the content of particles with a particle size of 10 μm or less in the raw activated carbon 8.9 vol% or less, an adsorption filter with excellent water permeability based on low water resistance can be obtained.

[0064] In the raw activated carbon, the content of particles with a particle size of 10 μm or less is preferably 2.7 vol% or more, more preferably 2.9 vol% or more, even more preferably 3.1 vol% or more, and particularly preferably 3.2 vol% or more. Furthermore, in the raw activated carbon, the content of particles with a particle size of 10 μm or less is preferably 8.0 vol% or less, more preferably 7.4 vol% or less, even more preferably 6.8 vol% or less, and particularly preferably 6.3 vol% or less.

[0065] There are no particular restrictions on the type of activated carbon used as long as it meets the requirements of D50, D90, and the content of particles with a diameter of less than 10 μm. It can be used alone or in combination with two or more activated carbons with different properties. When using two or more activated carbons in combination, the content of particles with a diameter of less than 10 μm varies depending on the properties of each activated carbon and their proportions. Therefore, its value can be controlled by appropriately selecting and / or adjusting it.

[0066] In this specification, the D50, D90, and particle size content of the raw activated carbon can be controlled, for example, by appropriately selecting and / or adjusting the type of carbonaceous material used as the raw material for activated carbon, as well as the activation treatment method and conditions (heating temperature and time, etc.), pulverization conditions, and grading conditions during the manufacture of activated carbon. Furthermore, the D50, D90, and particle size content of the raw activated carbon, as described in the examples below, can be analyzed and determined, for example, by using a wet particle size analyzer (Microtrac MT3300EX-II manufactured by Microtrac BEL) or a laser diffraction and scattering method.

[0067] Commercially available activated carbon can be used as raw material. Alternatively, activated carbon can be obtained by carbonizing the carbonaceous material used as raw material for activated carbon, followed by activation treatment, washing, drying, and pulverizing as needed.

[0068] There are no particular limitations on the carbonaceous materials used as raw materials. Examples include: plant-based carbonaceous materials (such as wood, wood shavings, charcoal, fruit shells such as coconut and walnut shells, fruit seeds, byproducts of pulp production, lignin, and waste molasses); mineral-based carbonaceous materials (such as peat, lignite, brown coal, bituminous coal, anthracite, coke, coal tar, coal pitch, petroleum distillation residues, and petroleum pitch); synthetic resin-based carbonaceous materials (such as phenolic resin, polyvinylidene chloride, and acrylic resins); and natural fiber-based carbonaceous materials (such as natural fibers like cellulose and regenerated fibers like rayon). These carbonaceous materials can be used alone or in combination of two or more.

[0069] Among these carbonaceous materials, coconut shells or phenolic resins are preferred from the viewpoint that they facilitate the development of micron-sized pores, which are related to the volatile organic compound removal performance specified in JIS S 3201:2019.

[0070] When carbonization is required, these carbonaceous materials can typically be carbonized in an oxygen- or air-isolated environment at, for example, around 400–800°C, preferably 500–800°C, and more preferably 550–750°C. The particle size can then be adjusted as needed.

[0071] Next, the carbonaceous material is activated. Activation treatment involves forming micropores on the surface of the carbonaceous material, transforming it into porous activated carbon. Activation treatment can be performed using general methods in this technical field and is not particularly limited; two main methods are gas activation treatment and chemical reagent activation treatment. However, in the case of water purification, gas activation treatment is preferred from the viewpoint of minimizing residual impurities.

[0072] Gas activation treatment involves heating carbonaceous materials in the presence of gases such as water vapor, carbon dioxide, air, oxygen, combustion gases, or mixtures thereof. The heating temperature is not particularly limited, but is typically between 700°C and 1100°C, preferably between 800°C and 980°C, and more preferably around 850°C to 950°C. The activation time and heating rate are not particularly limited and can be adjusted appropriately depending on the type, shape, and size of the selected carbonaceous material. Considering safety and reactivity, it is preferable to use a water vapor gas containing 10% to 40% by volume of water vapor. Chemical activation treatment is performed by mixing activators such as zinc chloride, calcium chloride, phosphoric acid, sulfuric acid, sodium hydroxide, potassium hydroxide, magnesium hydroxide, and calcium hydroxide with the carbonaceous material and heating it in an inert gas atmosphere.

[0073] After activation, the activated carbon is washed and dried as needed. Specifically, when using plant-based or mineral-based carbonaceous materials such as coconut shells containing impurities such as alkali metals, alkaline earth metals, and transition metals as raw materials for activated carbon, washing is necessary to remove ash or chemical reagents. Inorganic acids or water are used for washing; hydrochloric acid, which has high washing efficiency, is preferred.

[0074] After activation, the activated carbon undergoes further pulverization and / or grading as needed. Pulverization can be carried out using pulverizing equipment commonly used for pulverizing activated carbon, such as air-jet mills, rod mills, roller mills, hammer mills, abrasive mills, pin mills, high-speed rotary mills, ball mills, jet mills, etc. Grading methods commonly used for activated carbon include, for example, grading using sieves, wet grading, and dry grading. Wet grading machines include those utilizing principles such as gravity grading, inertial grading, hydraulic grading, and centrifugal grading. Dry grading machines include those utilizing principles such as sedimentation grading, mechanical grading, and centrifugal grading.

[0075] The activated carbon obtained through this process, or commercially available activated carbon, can be in any form, such as powder, granules, or fibers (filaments, woven fabric, felt), and the appropriate shape can be selected according to the application. Among these shapes, powder with high adsorption capacity per unit volume is preferred.

[0076] (Adhesive)

[0077] The binder used in the adsorption filter of this embodiment is not particularly limited, and a powdered or fibrous binder can be used alone or in combination of two or more. From the viewpoint of excellent water permeability when molding the adsorption filter, a fibrous binder is preferred.

[0078] As a fibrous binder, there are no particular limitations as long as it can be wound and shaped around activated carbon; both synthetic and natural products can be widely used. Examples of such binders include: acrylic fibers, polyethylene fibers, polypropylene fibers, polyacrylonitrile fibers, cellulose fibers, nylon fibers, aramid fibers, and pulp. The fiber length of the fibrous binder is preferably 4 mm or less.

[0079] The fibrous binder preferably comprises an acrylic-based fibrous binder. Additionally, the fibrous binder preferably comprises a cellulose-based fibrous binder. Furthermore, two or more of these fibrous binders can be used in combination. For example, it is more preferable to use both an acrylic-based fibrous binder and a cellulose-based fibrous binder in combination. By using the cellulose-based fibrous binder in combination, the amount of fine powder flowing out of the adsorption filter of this embodiment can be reduced. Regarding the mixing ratio of the acrylic-based fibrous binder and the cellulose-based fibrous binder, the cellulose-based fibrous binder is preferably 30 to 70 parts by weight, more preferably 40 to 60 parts by weight, relative to 100 parts by weight of the acrylic-based fibrous binder.

[0080] In this embodiment, the water permeability of the fibrous binder, expressed as a CSF value, is preferably about 1 mL to 200 mL. Furthermore, a CSF value of 10 mL to 150 mL is more preferable. Here, in this specification, the CSF value is the value determined by the Canadian Standard Freeness Method, as specified in JIS P 8121:2012, "Test Method for Filterability of Pulp". Specifically, it is the value evaluated using tap water with a conductivity of approximately 100 μS / cm. It should be noted that the CSF value can be adjusted, for example, by fibrillating the binder.

[0081] By ensuring the CSF value of the fibrous binder is 1 mL or higher, sufficient water permeability can be maintained, suppressing the reduction in strength of the molded body and preventing the possibility of pressure loss. Furthermore, by ensuring the CSF value is 200 mL or lower, the powdered activated carbon can be sufficiently retained, further suppressing the reduction in strength of the molded body and preventing the possibility of decreased adsorption performance. It should be noted that when two or more fibrous binders are used in combination, it is preferable that the CSF value of the mixed state of the two or more fibrous binders meets the above-mentioned range.

[0082] Specifically, when the fibrous binder includes an acrylic-based fibrous binder, the CSF value of the acrylic-based fibrous binder is preferably 20 mL or more, more preferably 50 mL or more. Furthermore, the CSF value of the acrylic-based fibrous binder is preferably 200 mL or less, more preferably 150 mL or less. By setting this range, even when the fibrous binder includes other fibrous binders besides the acrylic-based fibrous binder, the overall CSF value of the fibrous binder including the acrylic-based fibrous binder becomes an appropriate value, which can improve the strength of the molded article, reduce pressure loss, retain powdered activated carbon, and maintain adsorption performance. Furthermore, from the same viewpoint, when the fibrous binder includes both an acrylic-based fibrous binder and a cellulose-based fibrous binder, the cellulose-based fibrous binder preferably has a CSF value of 1 mL or more, more preferably 10 mL or more, in the state where 100 parts by weight of the acrylic-based fibrous binder is mixed with 50 parts by weight of the cellulose-based fibrous binder. Furthermore, the cellulose-based fibrous binder preferably has a CSF value of 50 mL or less, more preferably 40 mL or less, when 100 parts by weight of the acrylic fibrous binder is mixed with 50 parts by weight of the cellulose-based fibrous binder.

[0083] The ratio of activated carbon to binder is not particularly limited, but can be appropriately set such that, after molding the adsorption filter, the pore volume with a pore diameter of 15 μm or more and 30 μm or less (and preferably a pore volume with a pore diameter of 7 μm or less) falls within the specific range specified in this embodiment. For example, considering the adsorption performance of activated carbon and the formability of the adsorption filter, the binder is preferably about 2 to 8 parts by mass relative to 100 parts by mass of activated carbon. By setting the amount of binder to 2 parts by mass or more, an adsorption filter with sufficient strength can be obtained. By setting the amount of binder to 8 parts by mass or less, the decrease in the adsorption performance of activated carbon in the adsorption filter can be suppressed.

[0084] The mixing ratio of the binder to 100 parts by weight of activated carbon is more preferably 3 parts by weight or more, and even more preferably 4 parts by weight or more. Furthermore, the mixing ratio of the binder to 100 parts by weight of activated carbon is more preferably 7 parts by weight or less, and even more preferably 6 parts by weight or less. Additionally, when lead adsorbents or the like described later are included, the mixing ratio of the binder is preferably the above-mentioned mixing ratio relative to the sum of the activated carbon and the lead adsorbent.

[0085] (Any ingredients)

[0086] Furthermore, the adsorption filter of this embodiment may also contain other arbitrary functional components, provided that the effect of the present invention is not impaired. Examples include zeolite-based powders (lead adsorbents), ion exchange resins, or chelating resins capable of adsorbing and removing soluble lead. Additionally, to impart antibacterial properties, various adsorbents containing silver ions or silver compounds may be included alone, or a combination of two or more may be included. As an example of such an adsorbent, silver-loaded activated carbon added in an amount that does not affect the physical properties of the adsorption filter of this embodiment is an example. The amount of these other arbitrary components is not particularly limited, and is appropriately set such that, after molding the adsorption filter, the pore volume with a pore diameter of 15 μm or more and 30 μm or less (and preferably a pore volume with a pore diameter of 7 μm or less) falls within the specific range specified in this embodiment. For example, 1 to 30 parts by mass may be included relative to 100 parts by mass of the entire adsorption filter.

[0087] The adsorption filter of this embodiment, which includes a molded body containing activated carbon and a binder, may also include a central core, or it may be a cylindrical adsorption filter. By making it cylindrical, water flow resistance can be reduced. In addition, when used as a filter cartridge by filling the housing as described later, it has the advantages of being able to easily install the filter cartridge into the water purifier and easily replace it.

[0088] As for the core material, there are no particular limitations as long as it can be inserted into the hollow part of the cylindrical adsorption filter to enhance its performance. Examples include triangular pipes, netron pipes, and ceramic filters. Alternatively, non-woven fabric can be wrapped around the outer periphery of the core material.

[0089] [Manufacturing method of adsorption filter]

[0090] The method for manufacturing the adsorption filter of this embodiment can be carried out by any method known to those skilled in the art, and is not particularly limited. From the viewpoint of manufacturing with high efficiency, the slurry suction method is preferred.

[0091] Hereinafter, an example of a method for manufacturing the cylindrical adsorption filter according to this embodiment will be described in detail, but the method is not limited to this one.

[0092] Specifically, for example, the cylindrical adsorption filter (molded body) of this embodiment can be manufactured by a method including a slurry preparation step, a filtration step, a rotation step performed as needed, a drying step, and a grinding step performed as needed. In the slurry preparation step, powdered activated carbon and fibrous binder are dispersed in water to prepare a slurry. In the filtration step, the prepared slurry is drawn in and filtered to obtain a preformed body. In the rotation step, the preformed body after filtration is compressed on a shaping table, and the shape of the outer surface is adjusted as needed. In the drying step, the shaped preformed body is dried to obtain a dried molded body. In the grinding step, the outer surface of the dried molded body is ground as needed. The individual steps will be described in more detail below.

[0093] (Slurry preparation process)

[0094] In the slurry preparation process, for example, a slurry is prepared by dispersing the powdered activated carbon and the fibrous binder in a solvent, with the fibrous binder comprising 2 to 8 parts by mass relative to 100 parts by mass of powdered activated carbon, and the solid content concentration being 0.1% to 10% by mass, preferably 1% to 5% by mass. The solvent is not particularly limited, but water is preferred. By adjusting the solid content concentration of the slurry to a moderate level, uniform dispersion can be easily achieved, preventing unevenness in the molded body. On the other hand, by adjusting the solid content concentration of the slurry to a moderate level, molding time can be shortened, increasing productivity. Furthermore, it prevents the density of the molded body from becoming excessively high, maintaining good water permeability.

[0095] (Filtering process)

[0096] use Figure 1 Explain the vacuum filtration process. Figure 1 In the accompanying drawings, the reference numerals indicate: template 1, core 2, suction hole 3, flanges 4 and 4', and filtrate outlet 5. In the suction filtration process, for example... Figure 1 The template 1 shown is a cylindrical molding body with multiple suction holes 3 on the surface of the core 2, flanges 4 and 4' installed at both ends, and a filtrate outlet 5. First, the core as described above is installed in the template 1 and placed in the prepared slurry. Filtration is performed while suction is applied from the inside of the template 1 through the filtrate outlet 5, thereby adhering the slurry to the template 1. Conventional methods can be used for suction, such as using a suction pump. This adheres the preform to the template 1.

[0097] (Rotation process)

[0098] If necessary, a rotation process can be performed after the filtration process to adjust the outer diameter of the preform to a specified size, improve roundness, and reduce unevenness on the outer circumference. In the rotation process, the template 1 with the preform attached obtained in the filtration process is placed on the table, and it is moved back and forth while being pressed with a specified force.

[0099] It should be noted that, in order to obtain the required pore volume and the density of the adsorption filter, the filtration process and the rotation process, which need to be performed, can be carried out any number of times.

[0100] (Drying process)

[0101] Next, the flanges 4 and 4' at both ends of the template 1 are removed, and the core 2 is pulled out. This yields a hollow cylindrical preform. In the drying process, the preform removed from the template 1 as described above is dried using a dryer or similar equipment to obtain... Figure 2 The molded body 6 shown is the adsorption filter of this embodiment.

[0102] The drying temperature is, for example, 100℃~150℃, especially around 110℃~130℃. The drying time is, for example, 4~24 hours, especially around 8~16 hours. By setting the drying temperature to a moderate level, it is possible to prevent the filtration performance from decreasing or the strength of the molded body from decreasing due to the deterioration or melting of the fibrous binder. By setting the drying temperature to a moderate level, the drying time can be shortened, and incomplete drying can be prevented.

[0103] (Grinding process)

[0104] If necessary, a grinding process can be performed after the drying process to further adjust the outer diameter of the adsorption filter or reduce the unevenness of the outer circumference. The grinding method is not particularly limited as long as it can grind (or polish) the outer surface of the dried molded body; any grinding method known to those skilled in the art can be used. From the viewpoint of grinding uniformity, a grinding machine that rotates the molded body itself during grinding is preferred.

[0105] It should be noted that the grinding process is not limited to using a grinding machine. For example, a fixed flat grinding stone can be used to grind a shaped body fixed to a rotating shaft. In this method, the resulting grinding chips tend to accumulate on the grinding surface, so grinding while blowing air is effective.

[0106] [Applications of adsorption filters, etc.]

[0107] The adsorption filter of this embodiment can be used as, for example, a water purification filter or a filter for artificial dialysis. When used as a water purification filter or a filter for artificial dialysis, the adsorption filter is manufactured using the manufacturing method described above, shaped and dried, and then cut to the desired size and shape for use as a filter. Furthermore, a cover can be installed on the front end or a non-woven fabric can be installed on the surface as needed.

[0108] The adsorption filter of this embodiment can be filled into the housing and used as a water purification filter element. The water purification filter element is installed in a water purifier for water circulation. The water circulation method can be a total filtration method that filters the entire volume of raw water or a circulating filtration method. For example, the water purification filter (the adsorption filter of this embodiment) can be filled into the housing and used in the water purifier. Alternatively, the water purification filter can be further combined with known non-woven fabric filters, various adsorbents, mineral additives, ceramic filter materials, etc.

[0109] The above provides an overview of the present invention, and the adsorption filter of this embodiment is summarized below.

[0110] The first aspect of the present invention relates to an adsorption filter comprising a molded body containing activated carbon and a binder, wherein,

[0111] The volumetric pore volume of the adsorption filter, determined using mercury porosimetry, is 0.06 cm³, with a pore diameter of 15 μm or more and 30 μm or less. 3 / cc~0.30cm 3 / cc.

[0112] Alternatively, the second aspect of the invention relates to an adsorption filter comprising a molded body containing activated carbon and a binder, wherein,

[0113] In the cumulative particle size distribution of the activated carbon based on volume, D50 is 30 μm or more and 110 μm or less, D90 is 110 μm or more, and...

[0114] The activated carbon has a particle size of less than 10 μm and a particle content of more than 1.2% by volume and less than 8.9% by volume.

[0115] In the adsorption filter described in the first or second aspect, preferably, the pore diameter of the adsorption filter, as determined by mercury porosimetry, is less than 7 μm, and the pore volume is 0.10 cm³. 3 / cc or more.

[0116] In the adsorption filter related to the first aspect, it is preferable that, in the cumulative particle size distribution of the activated carbon on a volume basis, D50 is 30 μm or more and 110 μm or less, D90 is 110 μm or more, and...

[0117] The activated carbon has a particle size of less than 10 μm and a particle content of more than 1.2% by volume and less than 8.9% by volume.

[0118] Example

[0119] The present invention will be further described in detail below through embodiments; however, the present invention is not limited to any of the embodiments.

[0120] First, the raw materials used in each embodiment and comparative example, the methods for measuring the physical properties of the raw material powdered activated carbon, and the methods for measuring and evaluating the physical properties of the manufactured adsorption filters will be described in detail.

[0121] [Raw materials for adsorption filters]

[0122] The following describes a method for manufacturing activated carbon (powdered activated carbon) used as a raw material; however, the manufacturing method is not particularly limited as long as the necessary physical properties are met.

[0123] Powdered activated carbon A

[0124] Coconut shell activated carbon, obtained by carbonizing coconut shells from the Philippines, was activated with steam at 900°C. The resulting activated carbon was washed with dilute hydrochloric acid and desalinated with ion-exchange water to obtain granular activated carbon. The granular activated carbon was then pulverized using a ball mill to obtain powdered activated carbon A with D10 of 15 μm, D50 of 85 μm, and D90 of 159 μm.

[0125] Powdered activated carbon B

[0126] Granular activated carbon was obtained using the same method as powdered activated carbon A. The obtained granular activated carbon was then pulverized using a ball mill to obtain powdered activated carbon B with D10 of 14 μm, D50 of 60 μm, and D90 of 152 μm.

[0127] Powdered activated carbon C

[0128] Granular activated carbon was obtained using the same method as powdered activated carbon A. The obtained granular activated carbon was then pulverized using a ball mill to obtain powdered activated carbon C with D10 of 18 μm, D50 of 55 μm, and D90 of 152 μm.

[0129] Powdered activated carbon D

[0130] Granular activated carbon was obtained using the same method as powdered activated carbon A. The obtained granular activated carbon was pulverized using a ball mill to obtain powdered activated carbon D with D10 of 15 μm, D50 of 86 μm, and D90 of 164 μm.

[0131] Powdered activated carbon E

[0132] Granular activated carbon was obtained using the same method as powdered activated carbon A. The obtained granular activated carbon was then pulverized using a ball mill to obtain powdered activated carbon E with D10 of 18 μm, D50 of 45 μm, and D90 of 130 μm.

[0133] Powdered activated carbon F

[0134] Granular activated carbon was obtained using the same method as powdered activated carbon A. The obtained granular activated carbon was then pulverized using a ball mill to obtain powdered activated carbon F with D10 of 18 μm, D50 of 44 μm, and D90 of 120 μm.

[0135] Powdered activated carbon G

[0136] Granular activated carbon was obtained using the same method as powdered activated carbon A. The obtained granular activated carbon was then pulverized using a ball mill to obtain powdered activated carbon G with D10 of 16 μm, D50 of 32 μm, and D90 of 58 μm.

[0137] Powdered activated carbon H

[0138] Granular activated carbon was obtained using the same method as powdered activated carbon A. The obtained granular activated carbon was then pulverized using a ball mill to obtain powdered activated carbon H with D10 of 13 μm, D50 of 108 μm, and D90 of 194 μm.

[0139] Powdered activated carbon I

[0140] Granular activated carbon was obtained using the same method as powdered activated carbon A. The obtained granular activated carbon was then pulverized using a roller mill to obtain powdered activated carbon I with D10 of 72 μm, D50 of 138 μm, and D90 of 215 μm.

[0141] Powdered activated carbon J

[0142] Granular activated carbon was obtained using the same method as powdered activated carbon A. The obtained granular activated carbon was pulverized using a ball mill and then dry-classified. Finally, powdered activated carbon J with D10 of 24 μm, D50 of 58 μm, and D90 of 149 μm was obtained.

[0143] Powdered activated carbon K

[0144] Granular activated carbon was obtained using the same method as powdered activated carbon A. The obtained granular activated carbon was then pulverized using a ball mill to obtain powdered activated carbon K with D10 of 10 μm, D50 of 32 μm, and D90 of 66 μm.

[0145] The physical properties of powdered activated carbon A to powdered activated carbon K, together with the physical properties and evaluation results of the adsorption filter, are summarized in Tables 3 and 4 below.

[0146] (Adhesive)

[0147] Acrylic fibrous adhesive: Manufactured by Exlan Industries, Ltd., Japan, "Acrylic Fiber Bi-PUL / F", CSF value 83ml

[0148] Cellulose-based fibrous binder (the CSF value is 28 mL when 50 parts by weight of the cellulose-based fibrous binder are mixed with 100 parts by weight of the above-mentioned acrylic fibrous binder (CSF value 83 mL)).

[0149] (other)

[0150] Titanium silicate-based lead adsorbent: manufactured by Solens, "ATS", average particle size 20 μm

[0151] SMIC: Manufactured by Daiwabo Progress Co., Ltd., "PMF-30C-12-14"

[0152] Nonwoven fabric: Manufactured by Shinwa Co., Ltd., "9540-F"

[0153] [Particle size distribution determination of raw activated carbon]

[0154] The D10 (μm), D50 (μm), and D90 (μm) of the raw activated carbon, as well as the content (volume %) of particles with a diameter of less than 10 μm, were determined using laser diffraction and scattering. Specifically, the activated carbon to be measured was added together with a surfactant to ion-exchanged water, and a uniform dispersion was prepared by ultrasonic vibration. The dispersion was then measured using a wet particle size analyzer (Microtrac MT3300EX-II, manufactured by Microtrac). The surfactant used was "polyoxyethylene (10) octylphenyl ether," manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd. The analytical conditions are shown below.

[0155] (Analysis conditions)

[0156] Number of measurements; average of 3 measurements.

[0157] Measurement time: 30 seconds

[0158] Distribution display; volume

[0159] Particle size classification; standards

[0160] Calculation mode; MT3000II

[0161] Solvent name: Water

[0162] Upper limit of detection: 2000 μm; Lower limit of detection: 0.021 μm

[0163] Residual component ratio: 0.00

[0164] By component ratio; 0.00

[0165] Residual component ratio setting; ineffective

[0166] Particle permeability; absorption

[0167] Particle refractive index; Not applicable (N / A)

[0168] Particle shape; Not applicable (N / A)

[0169] Solvent refractive index: 1.333

[0170] DV value: 0.0882

[0171] Transmittance (TR): 0.880–0.900

[0172] Expanded filter; ineffective

[0173] Flow rate: 70%

[0174] Ultrasonic output; 40W

[0175] Ultrasound duration: 180 seconds

[0176] [Density Measurement of Adsorption Filters]

[0177] After drying the obtained adsorption filter at 120℃ for 2 hours, the density of the adsorption filter (g / cm³) was calculated according to the following formula. 3 It should be noted that the density of the adsorption filter refers to the density of the activated carbon forming layer itself.

[0178] Adsorption filter density = (mass of the activated carbon forming layer of the adsorption filter) / (volume of the activated carbon forming layer of the adsorption filter)

[0179] [Measuring the pore volume of the adsorption filter using a mercury porosimeter]

[0180] The pore volume of the adsorption filter was determined using a mercury porosimetry apparatus (MicroActive AutoPore V9620, manufactured by McMurray-Tec). The measurement pressure was set to 0.7 kPa–420 MPa. Figure 3 After cutting the cylindrical adsorption filter containing the activated carbon and binder, the cut slices were further cut into approximately 1 cm square pieces. The pore volume (cm³) of the approximately 1 cm square sample was calculated based on the weight of the adsorption filter sample, with a pore diameter of 15 μm or more and 30 μm or less. 3 / g), pore volume (cm³) with a pore diameter of less than 7μm. 3 / g) and total fine pore volume (cm³) 3 / g). Then, by multiplying these values ​​by the adsorption filter density calculated above, the pore volume (cm³) of the adsorption filter with a pore diameter of 15 μm or more and 30 μm or less was calculated as a volume-based standard. 3 / cc), pore volume (cm³) with a pore diameter of less than 7μm. 3 / cc) and total pore volume (cm³) 3 / cc).

[0181] [Evaluation of filtration capacity for turbid substances]

[0182] The turbidity filtration capacity of the adsorption filter is evaluated by conducting a water flow test using test water containing turbidity and calculating the turbidity removal life (L / cc) and turbidity clogging life (L / cc). These are determined and calculated using the methods described below.

[0183] First, kaolin clay (manufactured by Nacalai Tesque, Inc.) with a particle size of 0.1 μm to 4 μm was used as the turbidity material. Diluted water with a turbidity of 2 degrees was adjusted to a temperature of 20 ± 3 °C and used as the test water. This test water was passed from the outside to the inside of the obtained cylindrical adsorption filter while maintaining a dynamic water pressure of 0.1 MPa, and the flow rate was measured over time. Simultaneously, both the test water and the treated water were extracted as samples. The turbidity of these samples at a wavelength of 660 nm was measured using a spectrophotometer (manufactured by Shimadzu Corporation, "UV-1900") and a cylindrical 50 mm quartz cell. Based on these results, the removal rate (%) of the turbidity contained in the test water was calculated. Furthermore, the cumulative water flow per unit volume of the adsorption filter when the turbidity removal rate was less than 80% was calculated as the turbidity removal lifetime (L / cc). In this test, a turbidity removal rate lifetime (L / cc) of 10.5L / cc or higher was used as the pass standard, and the adsorption filter was evaluated as being able to remove turbidity effectively over a long period of time.

[0184] Furthermore, the cumulative water flow per unit volume of the adsorption filter when the flow rate is less than half of what it was 10 minutes after the start of water flow was calculated as the turbidity clogging life (L / cc). In this test, a turbidity clogging life (L / cc) of 10.5 L / cc or higher was used as the pass standard, indicating that the adsorption filter does not allow turbidity to cause clogging and can maintain excellent water flow performance over a long period of time.

[0185] [Evaluation of filtration capacity for turbid substances during backwashing]

[0186] The turbidity filtration capacity of the adsorption filter under backwashing conditions was evaluated using the following method. A water flow test was conducted using test water containing turbidity while backwashing was performed, and the turbidity removal lifespan (L / cc) and turbidity clogging lifespan (L / cc) under this condition were calculated. These were determined and calculated using the methods described below.

[0187] Backwashing is performed every 5 hours starting from the start of the water flow test. Specifically, the water flow direction is reversed for one minute, meaning the test water flows from the inside to the outside of the cylindrical adsorption filter, maintaining a hydraulic pressure of 0.1 MPa. After one minute, the water flow direction is returned to its original direction, meaning the test water flows from the outside to the inside of the adsorption filter again, maintaining a hydraulic pressure of 0.1 MPa. Other steps, measurement methods, and calculation methods are the same as those for the turbidity removal rate lifetime (L / cc) and turbidity clogging lifetime (L / cc) described above.

[0188] In this test, a turbidity removal lifetime (L / cc) of 15.1 L / cc or higher under backwashing conditions was used as the pass standard, indicating that the adsorption filter can effectively remove turbidity while performing backwashing for a longer period. Furthermore, a turbidity clogging lifetime (L / cc) of 15.1 L / cc or higher under backwashing conditions was also used as the pass standard, indicating that the adsorption filter can maintain superior water permeability over a long period without clogging by turbidity during backwashing.

[0189] [Ultrafine Particle Removal Performance Measurement]

[0190] The ultrafine particle removal performance of the adsorption filter was determined using the following method. First, dilution water with a concentration of over 10,000 particles / ml was prepared using Fluoro-Max (trademark) GreenFluorescent Polymer Microspheres G500 (particle diameter 0.5 μm) manufactured by Thermo Fisher Scientific. The temperature of this dilution water was adjusted to 20 ± 3 °C, and this water was used as the test water. This test water was passed from the outside to the inside of the cylindrical adsorption filter at a flow rate of 1.9 L / min, and both the test water and the treated water were extracted over time to form samples. These samples were filtered using a 0.2 μm membrane filter (ADVANTEC, membrane filter A020B025A, white (cellulose mixed ester, 0.2 μm, 25 mm, with black grid lines) and dried at 60 °C. The number of fluorescent particles in the two samples was calculated by fixing the dried membrane filter on a glass slide and observing it under a fluorescence microscope (Olympus BX51-34-FL). The removal rate (%) of particles treated in the test water was also calculated. Furthermore, the cumulative water flow per unit volume of the adsorption filter when the particle removal rate was below 85% was calculated as the ultrafine particle removal lifetime (L / cc). In this experiment, an ultrafine particle removal lifetime (L / cc) of 10.5 L / cc or higher was used as the acceptance standard, evaluating the adsorption filter as capable of effectively removing ultrafine particles over a long period.

[0191] [Initial water flow resistance measurement]

[0192] Water at 20±3℃ was circulated from the outside to the inside of the cylindrical adsorption filter at a flow rate of 1.9 L / min. The water flow resistance (MPa) was measured 10 minutes after the start of water flow as the initial water flow resistance (MPa). Note that this water flow resistance value does not include the shell resistance.

[0193] [VOC Removal Performance Measurement]

[0194] The VOC removal performance of the adsorption filter was determined using the following method. First, dilution water with a chloroform concentration of 60 ± 12 ppb was prepared and its temperature was adjusted to 20 ± 3°C to serve as test water. This test water was then passed from the outside to the inside of the cylindrical adsorption filter at a flow rate of 1.9 L / min. Both the test water and treated water were extracted over time to form samples. The chloroform concentration in these samples was determined using ECD gas chromatography (“GC-2014”, manufactured by Shimadzu Corporation), and the removal rate (%) was calculated. Furthermore, the cumulative flow rate per unit volume of the adsorption filter when the chloroform removal rate was below 80% was calculated as the VOC removal lifetime (L / cc). In this test, a VOC removal lifetime (L / cc) of 10.5 L / cc or higher was considered acceptable, and the adsorption filter was evaluated as capable of effectively removing VOCs over a long period.

[0195] [Lead Removal Performance Test]

[0196] The lead removal performance of the adsorption filter was determined using the following method. First, dilution water with a lead concentration of 150 ± 15 ppb was prepared. The pH of this dilution water was adjusted to 8.30–8.60 using a sodium hydroxide aqueous solution, and the temperature was adjusted to 20 ± 3°C, serving as the test water. This test water was passed from the outside to the inside of the cylindrical adsorption filter at a flow rate of 1.9 L / min. Both the test water and treated water were extracted over time to form samples. The lead concentration in these samples was determined using an ultrasonic atomizer (“UAG-1”, manufactured by Shimadzu Corporation) and an ICP-based luminescence analyzer (“ICPE9820”, manufactured by Shimadzu Corporation). Furthermore, the cumulative flow rate per unit volume of the adsorption filter when the lead concentration in the treated water reached 10 ppb or higher was calculated as the lead removal lifetime (L / cc). In this test, a lead removal lifetime (L / cc) of 10.5 L / cc or higher was considered acceptable, and the adsorption filter was evaluated as capable of effectively removing lead over a long period.

[0197] The manufacturing methods of the adsorption filters in each embodiment and comparative example, the results of the physical property measurement of the manufactured adsorption filters, and the performance evaluation results will be described in detail below.

[0198] <Example 1>

[0199] Powdered activated carbon A, titanate-based lead adsorbent, acrylic-based fibrous binder, and cellulose-based fibrous binder were prepared in the proportions shown in Table 1 below, totaling 8.36 kg, with tap water added. The total volume of the slurry after addition was 83.6 L.

[0200] Next, the SMIC will be installed in the aforementioned... Figure 1The cylindrical molding template shown (outer diameter 40.0 mm φ, central shaft diameter 11.6 mm φ, and outer flange spacing 365.0 mm H) was used to mold the slurry obtained by suction at 400 mmHg until it reached a diameter of 43 mm φ, slightly larger than the outer diameter of the mold, and then dried. Next, the resulting molded body was installed... Figure 4 The automatic grinding machine shown grinded the outer surface of the molded body under the conditions of 360 revolutions / minute of the molded body, 2535 revolutions / minute of the grinding stone, and a grinding stone moving speed of 250mm / 10 seconds (2.5cm / second), resulting in a cylindrical adsorption filter with an outer diameter of 38.6mmφ, an inner diameter of 12mmφ, and a height of 108.0mmH.

[0201] The density and pore volume of the adsorption filter obtained as described above were determined using the methods described above. The results of the physical property measurements of the adsorption filter are summarized in Table 3 below.

[0202] Then, a layer of non-woven fabric was wrapped around the outer periphery of the resulting adsorption filter. Next, a cylindrical seal with an outer diameter of 39 mm and a thickness of approximately 1 mm, made of ABS resin, was bonded to one end of the adsorption filter using hot melt adhesive. Furthermore, a seal with an outer diameter of 39 mm, two 2.2 mm diameter holes in the center, and a screw portion for connection to the housing used for water flow testing was bonded to the other end of the adsorption filter using hot melt adhesive.

[0203] An adsorption filter wrapped with non-woven fabric and sealed with a sealant was inserted into a container with an average diameter of 50 mm, a length of approximately 117 mm, and a capacity of approximately 230 cm³. 3 The activated carbon was housed in an ABS resin casing. Using this device, water was passed through from the outside to the inside, and the following methods were used to evaluate its turbidity filtration capacity, turbidity filtration capacity under backwashing conditions, ultrafine particle removal performance, initial water flow resistance, VOC removal performance, and lead removal performance. These performance evaluation results are summarized in Table 3 below. It should be noted that Table 3 also records the particle content (volume %) of the raw activated carbon with a particle size of less than 10 μm, as determined by the above methods.

[0204] <Examples 2 to Examples 6>

[0205] As shown in Table 1 below, in Examples 2 to 6, powdered activated carbon B to powdered activated carbon F were used instead of powdered activated carbon A. Otherwise, cylindrical adsorption filters were obtained using the same method as in Example 1. The results of the physical property measurements and performance evaluations of the adsorption filters in Examples 2 to 6 are summarized in Table 3 below.

[0206] <Comparative Examples 1 to 5>

[0207] As shown in Table 2 below, in Comparative Examples 1 to 5, powdered activated carbon G to K were used instead of powdered activated carbon A as the raw material. Otherwise, cylindrical adsorption filters were obtained using the same method as in Example 1. The results of the physical property measurements and performance evaluations of the adsorption filters in Comparative Examples 1 to 5 are summarized in Table 4 below.

[0208] Table 1

[0209]

[0210] Table 2

[0211]

[0212] In Tables 1 and 2 above, "-" indicates that it does not contain. Furthermore, the amounts of acrylic-based fibrous binders and cellulose-based fibrous binders in Tables 1 and 2 are expressed as parts by mass relative to a total of 100 parts by mass of the raw materials activated carbon and titanate-based lead adsorbent.

[0213]

[0214]

[0215] also, Figure 5 The graph shows the results of water flow tests conducted using test water containing turbid substances in Examples 1-3 and Comparative Example 1. Furthermore, Figure 6 The graph shows the results of water flow tests using test water containing turbid substances during backwashing operations in Examples 1-3 and Comparative Example 1. Furthermore, Figure 7 The figure shows the results of water flow tests conducted using test water containing turbid substances in Examples 4-6. Figure 8 The figure shows the results of a water flow test using test water containing turbid substances during backwashing operations in Examples 4-6. Figure 9 The figure shows the results of water flow tests conducted using test water containing turbid substances in Comparative Examples 2-5. Figure 10 The figure shows the results of a water flow test using test water containing turbid substances during backwashing operations in Comparative Examples 2-5.

[0216] [Inspection]

[0217] As shown in Table 3 above, the adsorption filters of Examples 1-6 have a pore diameter of 15 μm or more and 30 μm or less, with a pore volume of 0.06 cm³. 3 / cc~0.30cm 3Within the range of / cc. Furthermore, the activated carbon (powdered activated carbon A-F) used in the adsorption filters of Examples 1-6 met all the conditions of a D50 of 30 μm or more and 110 μm or less, a D90 of 110 μm or more, and a particle content of 1.2 vol% or more and 8.9 vol% or less with a particle size of 10 μm or less. On the other hand, in the adsorption filters of Comparative Examples 1-5, the pore volume of pores with a diameter of 15 μm or more and 30 μm or less was 0.06 cm³. 3 / cc~0.30cm 3 Outside the range of / cc, or where there is no raw material activated carbon with a D50 of 30μm or more and 110μm or less, a D90 of 110μm or more, and a particle content of 1.2% by volume or more and 8.9% by volume or less.

[0218] As shown in Tables 3 and 4 above, and Figure 5 and Figure 7 As shown, compared to the adsorption filter of Comparative Example 1, the adsorption filters of Examples 1-6 not only effectively removed ultrafine particles and turbid substances over a long period of time, but also maintained excellent water permeability. Furthermore, as shown in Tables 3 and 4 above, the initial water flow resistance of the adsorption filters of Examples 1-6 was also lower than that of the adsorption filter of Comparative Example 1. It is believed that this is because the adsorption filter of Comparative Example 1, with its smaller activated carbon particle size, could remove ultrafine particles as effectively as the filters of Examples 1-6; however, it became clogged due to larger turbid substances, resulting in poor water permeability and ultimately a shorter lifespan for the adsorption filter.

[0219] In addition, as shown in Table 3 above and Figure 6 and Figure 8 As shown, the adsorption filters of Examples 1-6 exhibit high regeneration efficiency based on backwashing flow rates, maintaining good turbidity removal performance over a longer period. On the other hand, it is believed that in the adsorption filter of Comparative Example 1, the particle size of the raw material activated carbon is small, making it difficult to release turbid substances even after backwashing, thus ultimately failing to extend the lifespan of the adsorption filter.

[0220] Compared to the adsorption filters of Examples 1-6, the adsorption filter of Comparative Example 2 had good water permeability, but its performance in removing turbid substances (including in cases of backwashing) and ultrafine particles was poor, and its filter life was shortened. This is believed to be because, compared to Examples 1-6, the pore diameter of the adsorption filter was distributed over a larger area.

[0221] Compared to the adsorption filters of Examples 1-6, the adsorption filter of Comparative Example 3 also exhibited good water permeability, but its performance in removing turbid substances (including in cases of backwashing) and ultrafine particles was poor, resulting in a shorter filter lifespan. This is believed to be due to the significantly larger particle size of the activated carbon used as raw material compared to Examples 1-6.

[0222] Compared to the adsorption filters of Examples 1-6, the adsorption filter of Comparative Example 4 exhibited poorer performance in removing turbid substances (including in cases of backwashing) and a shorter filter life. This is believed to be due to the significantly lower content of activated carbon particles with a diameter of less than 10 μm compared to Examples 1-6.

[0223] Compared to the adsorption filters of Examples 1-6, the adsorption filter of Comparative Example 5 experienced clogging due to turbidity, resulting in poor water permeability and a shortened filter life. This is believed to be because, similar to Comparative Example 1, the particle size of the activated carbon used as the raw material was smaller than that of Examples 1-6.

[0224] Furthermore, as shown in Table 3 above, the adsorption filters of Examples 1 to 6 are able to effectively remove VOCs and lead, which is equivalent to harmful substances, over a long period of time.

[0225] This application is based on Japanese Patent Application No. 2022-053499, filed on March 29, 2022, the contents of which are incorporated herein by reference.

[0226] To illustrate the present invention, it has been appropriately and sufficiently described above with reference to specific examples and embodiments. However, it should be understood that modifications and / or improvements can be readily made to the described embodiments and embodiments by those skilled in the art. Therefore, any modified or improved embodiments implemented by those skilled in the art, as long as they do not depart from the scope of protection of the claims, can be interpreted as being included within the scope of protection of the claims.

[0227] Industrial availability

[0228] The adsorption filter of the present invention removes harmful substances such as free residual chlorine, trihalomethanes and other VOCs (volatile organic compounds), pesticides, and musty odors contained in tap water. Therefore, it is suitable for filling the shell and being used as a filter element for water purification.

Claims

1. An adsorption filter, comprising: A molded body comprising activated carbon and a binder, wherein, The volumetric pore volume of the adsorption filter, determined using mercury porosimetry, is 0.06 cm³, with a pore diameter of 15 μm or more and 30 μm or less. 3 / cc~0.30cm 3 / cc, and, The volume of the adsorption filter, measured using mercury porosimetry, is 0.12 cm³, with a pore diameter of less than 7 μm as a volume standard. 3 / cc or higher, The total pore volume of the adsorption filter, determined using mercury porosimetry as a volume standard, is 0.50 cm³. 3 / cc~0.73cm 3 / cc.

2. An adsorption filter, comprising: A molded body comprising activated carbon and a binder, wherein, In the volume-based cumulative particle size distribution of the activated carbon, D50 is 30 μm or more and 110 μm or less, and D90 is 110 μm or more. The activated carbon has a particle size of less than 10 μm, and the content of such particles is more than 1.2% by volume and less than 8.9% by volume. The volume of the adsorption filter, measured using mercury porosimetry, is 0.12 cm³, with a pore diameter of less than 7 μm as a volume standard. 3 / cc or higher, The total pore volume of the adsorption filter, determined using mercury porosimetry as a volume standard, is 0.50 cm³. 3 / cc~0.73cm 3 / cc.

3. The adsorption filter according to claim 1, wherein, In the cumulative particle size distribution of the activated carbon based on volume, D50 is 30 μm or more and 110 μm or less, D90 is 110 μm or more, and... The activated carbon has a particle size of less than 10 μm and a particle content of more than 1.2% by volume and less than 8.9% by volume.

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