Activated carbon filter body

Abstract

To provide an activated carbon filter body capable of making particle collection performance and clogging resistance compatible at a higher level.SOLUTION: A filter medium part 11 having a first active carbon molded layer 15 on the upstream side and a second active carbon molded layer 16 on the downstream side, wherein the first active carbon molded layer 15 has a total pore volume (Va1) of 0.30 to 0.1 75mL / g for pore diameters of 5 to 15 μm and a total pore volume (Vb1) of 0.45 to 1.0 10mL / g for pore diameters of 15 to 40 μ m, and the second active carbon molded layer 16 has a total pore volume (Va2) of 0.80 to 0.1 20mL / g for pore diameters of 5 to 15 μm and a total pore volume (Vb2) of 0. 40mL / g or less for pore diameters of 15 to 40 μ m, A difference (VDa) between the sum of void volumes (Va1) and the sum of void volumes (Va2) is - 0.70 to - 0. 05mL / g, and a difference (VDb) between the sum of void volumes (Vb1) and the sum of void volumes (Vb2) is 0.05 to 1. 10mL / g.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an activated carbon filter body. [Background technology]

[0002] Generally, water purifiers that filter liquids such as tap water and remove residual components and particles from the liquid use activated carbon filter bodies (activated carbon moldings) in which activated carbon, acting as an adsorbent, is molded into a predetermined shape using a binder. In this type of activated carbon filter body, residual components such as chloroform are adsorbed by the pores in the activated carbon, which serves as the adsorbent, and fine particles such as kaolin are captured by the gaps (gaps between the activated carbon particles) in the activated carbon moldings. In activated carbon filter bodies, the fine particle capture performance can be improved by reducing the gaps in the activated carbon moldings. However, reducing the gaps in the activated carbon moldings tends to increase the likelihood of clogging, and increasing the gaps in the activated carbon moldings to reduce clogging tends to decrease the fine particle capture performance.

[0003] Therefore, an activated carbon filter body that achieves both particle collection performance and clogging resistance has been proposed (see, for example, Patent Document 1). This filter body is made of a molded body containing activated carbon and a binder, and the physical properties of the molded body include a volume of 0.10 to 0.39 cm3 for pores with a diameter of 10 μm or more. 3 / cc, and the volume of the gaps with a diameter of 7 μm or less is 0.15 cm 3 / cc or more, and the total volume of the gap is 0.50 to 0.73 cm 3 This activated carbon filter body achieves both particle collection performance and resistance to clogging by mixing multiple activated carbons with different physical properties and controlling the volume and total volume corresponding to the specified pore diameter as described above.

[0004] In recent years, water purifier manufacturers and others have been increasingly demanding filters that combine high particle capture performance with low clogging resistance. As mentioned above, conventional activated carbon filter bodies have been designed to achieve high particle capture performance by controlling the volume of the pores in the activated carbon moldings, but controlling the pore diameter and volume within a single activated carbon molding layer has limited effectiveness and may not be able to meet the increasing performance requirements. Therefore, there is a strong demand for activated carbon filter bodies that can achieve both high particle capture performance and high clogging resistance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7180036 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above points, and aims to provide an activated carbon filter body that can achieve both particle collection performance and clogging resistance at a higher level. [Means for solving the problem]

[0007] That is, the first invention is a filter body having a hollow cylindrical filter medium portion containing an activated carbon material and a binder, the filter medium portion having a first activated carbon layer formed of one activated carbon material and disposed on the upstream side in the filtration direction, and a second activated carbon layer formed of another activated carbon material and disposed on the downstream side in the filtration direction, and the sum of the pore volumes (V) of pores with a pore diameter of 5 to 15 μm in the first activated carbon layer measured by mercury intrusion porosimetry a1 ) is 0.30 to 0.75 mL / g, and the sum of the pore volumes of pores with a diameter of 15 to 40 μm (V b1 ) is 0.45 to 1.10 mL / g, and the sum of the pore volumes (V a2) is 0.80 to 1.20 mL / g, and the sum of the pore volumes (V b2 ) is 0.40 mL / g or less, and the sum of the void volumes (V a1 ) and the sum of the void volumes of voids with a diameter of 5 to 15 μm in the second activated carbon molding layer (V a2 ) and the difference (V Da ) is -0.70 to -0.05 mL / g, and the sum of the void volumes (V b1 ) and the sum of the void volumes (V b2 ) and the difference (V Db ) is 0.05 to 1.10 mL / g.

[0008] (V Da )=(V a1 )-(V a2 ) … (i) (V Db )=(V b1 )-(V b2 ) … (ii)

[0009] The second invention relates to the activated carbon filter body of the first invention, wherein the pore mode diameter (M1) in the first activated carbon layer measured by mercury porosimetry is 15 to 25 μm, and the pore mode diameter (M2) in the second activated carbon layer measured by mercury porosimetry is 5 to 15 μm.

[0010] The third invention is the second invention, wherein the difference (M D ) is 5 to 15 μm.

[0011] (M D )=(M1)-(M2) … (iii)

[0012] A fourth invention is the method according to any one of the first to third inventions, wherein the layer thickness ratio (T2) of the second activated carbon layer to the layer thickness (T1) of the first activated carbon layer is defined by the following formula (iv): R ) is 0.24 to 9.33.

[0013] (T R )=(T2) / (T1) … (iv)

[0014] A fifth invention relates to the activated carbon filter body according to any one of the first to third inventions, wherein the first activated carbon molded layer and the second activated carbon molded layer are both formed by wet molding.

[0015] A sixth invention relates to the activated carbon filter body of the fourth invention, wherein the first activated carbon molded layer and the second activated carbon molded layer are both formed of wet molded bodies. [Effects of the Invention]

[0016] According to a first aspect of the present invention, there is provided an activated carbon filter body having a hollow cylindrical filter medium portion containing an activated carbon material and a binder, the filter medium portion having a first activated carbon layer formed of one activated carbon material and disposed upstream in the filtration direction, and a second activated carbon layer formed of another activated carbon material and disposed downstream in the filtration direction, and the sum of the pore volumes (V) of pores with a pore diameter of 5 to 15 μm in the first activated carbon layer measured by mercury porosimetry is a1 ) is 0.30 to 0.75 mL / g, and the sum of the pore volumes of pores with a diameter of 15 to 40 μm (V b1 ) is 0.45 to 1.10 mL / g, and the sum of the pore volumes (V a2 ) is 0.80 to 1.20 mL / g, and the sum of the pore volumes (V b2 ) is 0.40 mL / g or less, and the sum of the void volumes (V a1 ) and the sum of the void volumes of voids with a diameter of 5 to 15 μm in the second activated carbon molding layer (V a2 ) and the difference (VDa ) is -0.70 to -0.05 mL / g, and the sum of the void volumes (V b1 ) and the sum of the void volumes (V b2 ) and the difference (V Db ) is 0.05 to 1.10 mL / g, it is possible to achieve a high level of both particle collection performance and clogging resistance.

[0017] According to the activated carbon filter body of the second invention, in the first invention, the pore mode diameter (M1) in the first activated carbon layer measured by mercury porosimetry is 15 to 25 μm, and the pore mode diameter (M2) in the second activated carbon layer measured by mercury porosimetry is 5 to 15 μm, so that early clogging can be easily suppressed, and good particle collection performance and resistance to clogging can be maintained for a long period of time.

[0018] According to the activated carbon filter body of the third invention, in the second invention, the difference (M D ) is 5 to 15 μm, it is possible to achieve an appropriate balance between particle collection performance and clogging resistance.

[0019] According to the fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the activated carbon filter body is characterized in that the layer thickness ratio (T2) of the second activated carbon layer to the layer thickness (T1) of the first activated carbon layer is R ) is 0.24 to 9.33, the balance of the layer thicknesses of the first activated carbon molded layer and the second activated carbon molded layer can be adjusted, and both particle collection performance and clogging resistance can be appropriately achieved.

[0020] According to the activated carbon filter body of the fifth invention, in any one of the first to third inventions, the first activated carbon molding layer and the second activated carbon molding layer are both made of wet-molded moldings, so that the activated carbon filter body can be manufactured easily and efficiently.

[0021] According to the activated carbon filter body of the sixth invention, in the fourth invention, the first activated carbon molding layer and the second activated carbon molding layer are both made of wet-molded moldings, so that the activated carbon filter body can be manufactured easily and efficiently. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a perspective view showing an activated carbon filter body according to an embodiment of the present invention. [Figure 2] FIG. 2 is a partially cutaway perspective view of the activated carbon filter body of FIG. 1. [Figure 3] 1 is a schematic diagram showing how particles in a liquid are captured when the water is passed through an activated carbon filter body of the present invention. FIG. [Figure 4] FIG. 2 is a schematic diagram showing the positions of test pieces cut out from a hollow cylindrical activated carbon filter body. DETAILED DESCRIPTION OF THE INVENTION

[0023] The activated carbon filter body of the present invention is intended to remove residual components and particles from liquids such as tap water, and is primarily installed in water purifiers. The activated carbon filter body can be made into a cartridge type as needed, allowing for easy installation and replacement in water purifiers. Cartridge-type activated carbon filter bodies can be used in home water purifiers, as well as in stationary types and larger devices with increased filtering capacity.

[0024] 1 and 2 show an activated carbon filter body 10 according to one embodiment of the present invention, which is an activated carbon molding having a hollow cylindrical filter element 11 containing activated carbon material and a binder. In the activated carbon filter body 10 of this embodiment, the side surface 12 of the filter element 11 is the upstream side in the filtration direction, and the hollow element 13 is the downstream side in the filtration direction, and water flows from the side surface 12 toward the hollow element 13. When selling or using this activated carbon filter body 10, its surface may be protected by covering it with a highly permeable fabric such as a nonwoven fabric, if necessary. In the figures, reference numeral 14 denotes the core of the filter element 11.

[0025] The activated carbon material is the main raw material constituting the filter media portion 11 and is obtained by carbonizing and activating the activated carbon raw material. This activated carbon material is configured in an appropriate form, such as powder, granules, or fiber. The activated carbon raw material can be coconut shells, wood (waste wood, thinnings, or sawdust), fruit, tires, coal, petroleum pitch, urethane resin, or phenolic resin. After carbonization, the activated carbon material undergoes activation treatment, such as steam activation, zinc chloride activation, phosphoric acid activation, sulfuric acid activation, air activation, or carbon dioxide activation, to develop pores. When natural raw materials are used, carbonization and activation facilitate the development of pores in the activated carbon material. When waste materials are used as raw materials, the raw materials can be procured inexpensively.

[0026] Activated carbon materials are equivalent to adsorbents that adsorb residual components such as chloroform and PFAS (per- and polyfluoroalkyl compounds) in liquids, and their adsorption performance is determined by the degree of development of the numerous pores formed by activation. Examples of indicators that indicate the adsorption performance of activated carbon materials include iodine adsorption performance, BET specific surface area, total pore volume, average pore diameter, and surface oxide amount. These indicators are adjusted appropriately depending on the substance to be adsorbed. From the viewpoint of achieving performance suitable for water purification applications, the activated carbon filter body of the present invention is, for example, set to have an iodine adsorption performance of 500 to 2000 mg / g and a BET specific surface area of ​​550 to 2200 m. 2 / g, the total pore volume is preferably 0.1 to 1.5 mL / g, the average pore diameter is 1.0 to 4.0 nm, and the amount of surface oxide is preferably 0.01 to 0.5 meq / g.

[0027] Iodine adsorption capacity is an index of free residual chlorine adsorption capacity and is calculated by measurements in accordance with JIS K 1474 (2014) or JIS K 1477 (2007). The preferred iodine adsorption capacity is 500 to 2000 mg / g, more preferably 600 to 1800 mg / g, and even more preferably 700 to 1600 mg / g. If the iodine adsorption capacity is too low, the free residual chlorine adsorption capacity may be insufficient. If the iodine adsorption capacity is too high, the strength of the activated carbon may decrease, leading to the risk of disintegration during use (filling, processing, water flow, etc.). Having appropriate iodine adsorption capacity provides excellent free residual chlorine adsorption capacity and good handling properties.

[0028] The BET specific surface area is an index showing the amount of pores formed in an activated carbon material. The greater the amount of pores (the larger the BET specific surface area) of an activated carbon material, the greater the amount of target adsorbate that can be adsorbed. Therefore, the BET specific surface area can be used as an index of the adsorption performance of residual components. This BET specific surface area is calculated from the straight line in the relative pressure range of 0.05 to 0.3 on the obtained curve by measuring the nitrogen adsorption isotherm at 77 K and analyzing it using the multipoint method based on the BET equation. The preferred BET specific surface area is 550 to 2200 m 2 / g, more preferably 700 to 1900m 2 / g, more preferably 800 to 1700m 2 / g. If the BET specific surface area is too small, the adsorption performance may be insufficient, while if the BET specific surface area is too large, the strength of the activated carbon may decrease, leading to the risk of it collapsing during use (packing, processing, passing water through, etc.). By providing an appropriate BET specific surface area, excellent adsorption performance for residual components and good handling properties can be obtained.

[0029] The total pore volume is an index of the adsorption / desorption performance of activated carbon materials, expressed from a different perspective than the BET specific surface area. This total pore volume is determined by analyzing the nitrogen gas adsorption isotherm of activated carbon using the Horvath-Kawazoe method (HK method). The preferred total pore volume is 0.1 to 1.5 mL / g, more preferably 0.2 to 1.3 mL / g, and even more preferably 0.3 to 1.2 mL / g. If the total pore volume is too small, the adsorption performance may be insufficient. If the total pore volume is too large, the strength of the activated carbon may decrease, and it may collapse during use (packing, processing, water flow, etc.). Having an appropriate total pore volume allows for excellent adsorption performance of residual components and good handleability.

[0030] The average pore diameter is an index showing the size of the pores formed in the activated carbon material. In activated carbon materials, the larger the pore diameter, the easier it is for substances with a larger molecular weight to be adsorbed. Therefore, the average pore diameter can be used as one index of the adsorption performance of the target adsorbate (here, the residual component). This average pore diameter is a value measured by the BET method, and is calculated from the following formula (i) assuming that the shape of the pores is cylindrical. The pore volume (mL / g) in formula (i) is determined by measuring the nitrogen adsorption isotherm at 77 K and analyzing the pore distribution by the DH method and the MP method, and the specific surface area (m 2 / g) is determined by measuring a nitrogen adsorption isotherm at 77K using the BET method. The preferred average pore diameter is 1.0 to 4.0 nm, more preferably 1.2 to 3.5 nm, and even more preferably 1.4 to 3.0 nm. If the average pore diameter is too small, the adsorption performance may decrease, while if the average pore diameter is too large, the adsorption performance of residual components with small molecular weights may decrease. By providing an appropriate average pore diameter, excellent adsorption performance of residual components can be obtained.

[0031]

number

[0032] The amount of surface oxides is a parameter that contributes to the removal performance of residual components such as chloroform and PFAS. Activated carbon materials have acidic functional groups, primarily hydrophilic groups such as carboxyl groups and phenolic hydroxyl groups, on their surfaces, which increase with surface oxidation. The amount of acidic functional groups present on the activated carbon surface affects the removal ability of residual components and can be understood as the amount of surface oxides. For example, if the amount of surface oxides on an activated carbon material is too high, the activated carbon surface becomes more hydrophilic, which may reduce the removal performance of hydrophobic residual components. On the other hand, if the amount of surface oxides on an activated carbon material is too low, the activated carbon surface becomes more hydrophobic, which is thought to reduce the removal performance of hydrophilic residual components.

[0033] Therefore, the preferred amount of surface oxides is 0.01 to 0.5 meq / g, more preferably 0.03 to 0.4 meq / g, and even more preferably 0.05 to 0.3 meq / g. As described above, the amount of surface oxides is appropriately adjusted depending on the degree of hydrophobicity or hydrophilicity of the residual components to be adsorbed. By using an appropriate amount of surface oxides, excellent residual component removal performance can be obtained.

[0034] The binder is a material that is integrated with the activated carbon material to maintain its shape, and examples of such materials include acrylic fibers, aramid fibers, polyethylene fibers, and cellulose-based fibers. The fibrous binder is preferably a fibrillated fiber binder. The fibrillation of the fibers effectively entangles and integrates the activated carbon material. The blending ratio of the activated carbon material and the binder is appropriately determined depending on the physical properties of the activated carbon material used, such as particle size, the intended use, and the environment in which it is used.

[0035] In the activated carbon filter body 10 of the present invention, the filter medium portion 11 is composed of multiple layers, including a first activated carbon layer 15 and a second activated carbon layer 16, each having different properties. In the filter medium portion 11, the first activated carbon layer 15 is formed of one activated carbon material and is located upstream in the filtration direction. On the other hand, the second activated carbon layer 16 is formed of another activated carbon material different from the first activated carbon material and is located downstream in the filtration direction. In the filter medium portion 11 of this embodiment, the first activated carbon layer 15 is the layer that includes the side surface 12, and the second activated carbon layer 16 is the layer that forms the hollow portion 13. The first activated carbon layer 15 and the second activated carbon layer 16 are formed concentrically.

[0036] In the activated carbon filter body 10, the gaps (gaps between activated carbons) formed between the constituent materials of the filter part 11 are specified under predetermined conditions, thereby achieving both a higher level of particle collection performance and less clogging than conventional methods. That is, the sum of the gap volumes (V a1 ) is 0.30 to 0.75 mL / g, and the sum of the pore volumes of pores with a diameter of 15 to 40 μm (V b1 ) is 0.45 to 1.10 mL / g, and the sum of the void volumes (V a2 ) is 0.80 to 1.20 mL / g, and the sum of the pore volumes (V b2 ) is 0.40 mL / g or less, and the sum of the void volumes (V a1 ) and the sum of the void volumes of voids with a diameter of 5 to 15 μm in the second activated carbon molding layer 16 (V a2 ) and the difference (V Da ) is -0.70 to -0.05 mL / g, and the sum of the pore volumes (V b1 ) and the sum of the void volumes of voids with a diameter of 15 to 40 μm in the second activated carbon molding layer 16 (V b2 ) and the difference (V Db ) is 0.05 to 1.10 mL / g. (V Da )=(V a1 )-(V a2 ) … (i) (V Db )=(V b1 )-(V b2 ) … (ii)

[0037] The gap diameter (μm) indicates the size of the gaps formed between the activated carbon materials that constitute the first activated carbon molded layer 15 and the second activated carbon molded layer 16. The gap volume sum (mL / g) indicates the amount of gaps formed in the first activated carbon molded layer 15 and the second activated carbon molded layer 16. The gap diameter and gap volume sum are measured by the known mercury intrusion method.

[0038] Sum of gap volumes (V a1 , V a2 ) indicates the sum of the volumes of relatively small pores in the activated carbon bed, and is used as an index of the collection performance for fine particles. The difference in the sum of the pore volumes of pores with diameters of 5 to 15 μm as defined by the above formula (i) (V Da ) represents the relationship between the amount of small gaps in the first activated carbon layer 15 (upstream side) in the filter material section 11 and the amount of small gaps in the second activated carbon layer 16 (downstream side), and is used as one of the indicators of the balance between the particle collection performance and clogging resistance of the activated carbon filter body 10.

[0039] On the other hand, the sum of the void volumes (V b1 , V b2 ) indicates the sum of the pore volumes of medium-sized pores in the activated carbon bed, and is used as an index of the collection performance for particles larger than the fine particles mentioned above. The difference (V Db ) represents the relationship between the amount of medium gaps in the first activated carbon layer 15 (upstream side) in the filter material section 11 and the amount of medium gaps in the second activated carbon layer 16 (downstream side), and is used as one of the indicators of the balance between the particle collection performance and clogging resistance of the activated carbon filter body 10.

[0040] Therefore, in the activated carbon filter body 10 of the present invention, the difference in the sum of the pore volumes of pores with a pore diameter of 5 to 15 μm (V Da) is -0.70 to -0.05 mL / g, and the difference in the sum of the pore volumes of pores with a diameter of 15 to 40 μm (V Db ) is 0.05 to 1.10 mL / g, the filter material part 11 has a structure in which small gaps (gap diameter 5 to 15 μm) are formed more in the second activated carbon layer 16 which constitutes the downstream side than the first activated carbon layer 15 which constitutes the upstream side, and medium gaps (gap diameter 15 to 40 μm) are formed more in the first activated carbon layer 15 which constitutes the upstream side than the second activated carbon layer 16 which constitutes the downstream side.

[0041] Here, using the schematic diagram of Figure 3, we will explain how particles and the like in a liquid, such as tap water, are captured when the liquid is passed through the activated carbon filter body 10 having the above structure, assuming that fine particles are particles P1 and particles larger than particle P1 are particles P2. The arrow indicated by the symbol D in the figure indicates the direction of water flow.

[0042] When a liquid is passed through the activated carbon filter body 10, particles P2 are first captured in the first activated carbon layer 15 (upstream side), which has a relatively large number of medium-sized pores. On the other hand, although some particles (P1a) of particles P1 are captured in the first activated carbon layer 15, most particles (P1b) pass through the first activated carbon layer 15 to reach the downstream side and are captured in the second activated carbon layer 16 (downstream side), which has a relatively large number of small pores.

[0043] Here, the sum of the void volumes (V b1 The sum of the void volumes (V) of the second activated carbon layer 16 having a void diameter of 15 to 40 μm is preferably about 0.45 to 1.10 mL / g, more preferably about 0.50 to 1.05 mL / g, and even more preferably about 0.60 to 1.00 mL / g. b2 The sum of the void volumes (V) of the voids of the first activated carbon layer 15 having a void diameter of 15 to 40 μm is preferably about 0.40 mL / g or less, more preferably about 0.02 to 0.35 mL / g, and even more preferably about 0.04 to 0.30 mL / g. b1 ) is too small, the total volume of gaps with a diameter of 5 to 15 μm (V a1) becomes larger, and both particles P1 and P2 are more likely to be collected in the first activated carbon layer 15, which may accelerate clogging. b2 ) is too large, the total volume of gaps with a diameter of 5 to 15 μm (V a2 ) becomes smaller, and the collection performance for the particles P1 may become insufficient.

[0044] In addition, the sum of the void volumes (V a1 The sum of the void volumes (V) of the second activated carbon layer 16 with a void diameter of 5 to 15 μm is preferably about 0.30 to 0.75 mL / g, more preferably about 0.35 to 0.70 mL / g, and even more preferably about 0.40 to 0.70 mL / g. a2 The sum of the pore volumes (V) of the first activated carbon layer 15 with a pore diameter of 5 to 15 μm is preferably about 0.80 to 1.20 mL / g, more preferably about 0.80 to 1.15 mL / g, and even more preferably about 0.85 to 1.10 mL / g. a1 ) is too large, the total volume of gaps with a diameter of 15 to 40 μm (V b1 ) becomes smaller, and clogging may easily occur. a2 If the gap diameter is too small, the total gap volume (V b2 ) becomes large, and the collection performance for the particles P1 may become insufficient.

[0045] Furthermore, in the activated carbon filter body 10, the sum of the void volumes (V a1 ) and (V a2 ), the sum of the void volumes of the voids of 15 to 40 μm diameter in each activated carbon molding layer 15, 16 (V b1 ) and (V b2 ), and the difference between the sum of each void volume (V Da ) and (V Db By setting the numerical range of the particle collection capacity, an appropriate particle collection capacity is allocated to each of the molding layers 15 and 16.

[0046] The difference in the sum of the gap volumes between the upstream and downstream gaps with a diameter of 5 to 15 μm (V Da ) is preferably about -0.70 to -0.05 mL / g, more preferably about -0.68 to -0.10 mL / g, and even more preferably about -0.66 to -0.15 mL / g. In addition, the difference between the sum of the gap volumes of gaps with a diameter of 15 to 40 μm on the upstream side and the downstream side (V Db ) is preferably about 0.05 to 1.10 mL / g, more preferably about 0.15 to 1.03 mL / g, and even more preferably about 0.30 to 0.96 mL / g.

[0047] As described above, the activated carbon filter body 10 of the present invention has a structure in which the first activated carbon molding layer 15 with many medium-sized pores is arranged on the upstream side of the filter medium part 11, and the second activated carbon molding layer 16 with many small pores is arranged on the downstream side. Da ) and the difference in the sum of the void volumes of voids with diameters of 15 to 40 μm (V Db ) in the appropriate range, it is possible to capture relatively large particles (particles P2) on the upstream side and fine particles (particles P1) on the downstream side, and to remove particles in the liquid in stages according to their size. This makes it possible to appropriately avoid clogging that occurs early on the upstream side as with conventional activated carbon filters, and it is possible to achieve a high level of both particle collection performance and clogging resistance.

[0048] In the activated carbon filter body 10 of the present invention, it is preferable that the first activated carbon molding layer 15 constituting the upstream side of the filter medium portion 11 has properties suitable for capturing particles P2, and it is preferable that the second activated carbon molding layer 16 constituting the downstream side has properties suitable for capturing particles P1. The properties suitable for each of the first activated carbon molding layer 15 and the second activated carbon molding layer 16 to capture the respective collection targets can be determined using the gap mode diameter.

[0049] The pore mode diameter is a value indicating the mode of the pore distribution measured by mercury porosimetry, and is used as one of the indices indicating the preferable size of the target to be captured by the first activated carbon molding layer 15 and the second activated carbon molding layer 16. It is considered that the target can be captured smoothly when the pores formed in the first activated carbon molding layer 15 and the second activated carbon molding layer 16 have a diameter appropriate for the size of the target to be captured. Therefore, the preferable pore mode diameter (M1) in the first activated carbon molding layer 15 is 15 to 25 μm, and the preferable pore mode diameter (M2) in the second activated carbon molding layer 16 is 5 to 15 μm.

[0050] If the gap mode diameter (M1) in the first activated carbon molding layer 15 is too small, particles P1 may have difficulty passing through and clogging may occur, whereas if it is too large, particles P2 may not be properly captured. If the gap mode diameter (M1) in the first activated carbon molding layer 15 is 15 to 25 μm, particles P2 are easily captured and particles P1 can be properly passed through, which makes it easier to prevent early clogging on the upstream side and ensures good collection performance for particles P2.

[0051] If the gap mode diameter (M2) in the second activated carbon molded layer 16 is too small, clogging may occur easily, and if it is too large, particles P1 may not be properly captured. If the gap mode diameter (M2) in the second activated carbon molded layer 16 is 5 to 15 μm, particles P1 that have passed through the first activated carbon molded layer 15 can be easily captured, and good capturing performance can be maintained for a long period of time.

[0052] In addition, the gap mode diameter (M1) in the first activated carbon molded layer 15 and the gap mode diameter (M2) in the second activated carbon molded layer 16 are different from each other by the gap mode diameter difference (M D ) is preferably 5 to 15 μm. (M D )=(M1)-(M2) … (iii)

[0053] The difference in gap mode diameter between the first activated carbon molding layer 15 and the second activated carbon molding layer 16 (M D) can be used as an index to show the balance between collection performance and clogging resistance. D If the difference in gap mode diameter (M D ) in an appropriate range, it is possible to appropriately achieve both particle collection performance and resistance to clogging.

[0054] In the activated carbon filter body 10 of the present invention, the layer thickness ratio (T2) of the second activated carbon layer 16 to the layer thickness (T1) of the first activated carbon layer 15 is defined by the following formula (iv): R ) is preferably 0.24 to 9.33. (T R )=(T2) / (T1) … (iv)

[0055] Layer thickness ratio (T R The layer thickness ratio (T) can be used as an index representing the balance between the first activated carbon layer 15 suitable for capturing particles P2 and the second activated carbon layer 16 suitable for capturing particles P1. R If the value of the layer thickness ratio (T) is too small, the second activated carbon layer 16 may be too thin compared to the first activated carbon layer 15, resulting in insufficient collection performance. R If the value of (a) is too large, the first activated carbon layer 15 may be too thin relative to the second activated carbon layer 16, which may result in early clogging. By controlling the thicknesses of the first activated carbon layer 15 and the second activated carbon layer 16 that constitute the filter portion 11 within the above range, the balance of the thicknesses of the first activated carbon layer 15 and the second activated carbon layer 16 can be adjusted, thereby appropriately achieving both particle collection performance and resistance to clogging.

[0056] In the activated carbon filter body of the present invention, if necessary, another activated carbon molding layer may be provided between the first activated carbon molding layer and the second activated carbon molding layer to form a filter medium portion having three or more molding layers. The other activated carbon molding layer is not particularly limited as long as it has properties that do not impair the functions of the first activated carbon molding layer and the second activated carbon molding layer. For example, it may have properties equivalent to those of the first activated carbon molding layer and the second activated carbon molding layer, or properties intermediate between those of the first activated carbon molding layer and the second activated carbon molding layer, as appropriate.

[0057] In the activated carbon filter body of the present invention, the first activated carbon molding layer and the second activated carbon molding layer are preferably wet-molded bodies. In the wet-molding of the filter body, an activated carbon material, which is the main raw material of the filter medium, is mixed with a binder, such as a fibrous binder, that maintains the shape of the activated carbon material, and the mixture is sucked into an aqueous slurry and molded into a predetermined shape.

[0058] When forming the first activated carbon molding layer and the second activated carbon molding layer, the activated carbon material for the second activated carbon molding layer is mixed with a binder and wet-molded to form the second activated carbon molding layer, and then the activated carbon material for the first activated carbon molding layer is mixed with a binder and wet-molded to form the first activated carbon molding layer on the outside of the second activated carbon molding layer, thereby forming a multi-layer filter medium.Since the first activated carbon molding layer and the second activated carbon molding layer can be formed consecutively by wet-molding, the activated carbon filter body can be easily and efficiently manufactured.If another activated carbon molding layer is provided between the first activated carbon molding layer and the second activated carbon molding layer, it can be easily manufactured by molding them in the same order from the inner layer side.

[0059] The first activated carbon molding layer and the second activated carbon molding layer are wet-molded bodies, so that the activated carbon material, which is the filter material, and the binder are intertwined and integrated into a structure. Therefore, it is possible to appropriately ensure particle collection performance while maintaining water permeability. Therefore, it is suitable as a structure for the filter material part 11 to achieve both particle collection performance and clogging resistance. [Example]

[0060] [Preparation of activated carbon filter body] Using the activated carbon material and binder described below, activated carbon filter bodies of prototype examples 1 to 12, each consisting of a first activated carbon molding layer and a second activated carbon molding layer; activated carbon filter bodies of prototype examples 13 and 14, each consisting of a first activated carbon molding layer, an intermediate activated carbon molding layer, and a second activated carbon molding layer; and activated carbon filter bodies of comparative examples 1 to 13, each consisting of a single activated carbon molding layer, were produced according to the following procedure.

[0061] First, a mixed slurry corresponding to each prototype and comparative example was prepared. The amount of water in the mixed slurry was 20 times the weight of the added solids. A nonwoven fabric made of polyethylene and polypropylene was wrapped around a hollow cylindrical polypropylene core material with an outer diameter of 34 mm, an inner diameter of 30 mm, a total length of 60 mm, and a 2 mm diameter through-hole, and a porous stainless steel mold rod was inserted and fixed into the core material.

[0062] In Experimental Examples 1 to 12, a mold rod containing a core wrapped in nonwoven fabric was placed in the mixed slurry for the second activated carbon molding layer, and solids were drawn from the mixed slurry by vacuum suction to deposit a predetermined thickness of solids for the second activated carbon molding layer on the surface of the core, forming a coating for the second activated carbon molding layer on the surface of the core. The core, with the second activated carbon molding layer coated thereon, was then placed in the mixed slurry for the first activated carbon molding layer, and solids were drawn from the mixed slurry by vacuum suction to deposit a predetermined thickness of solids for the first activated carbon molding layer on the surface of the coating for the second activated carbon molding layer, forming a coating for the first activated carbon molding layer. The mold rod was removed from the core, yielding an adsorbent adsorbent consisting of two coating layers (molded layers) and the core, all integrated together.

[0063] In Examples 13 and 14, a coating for the second activated carbon molding layer was formed on the surface of a core material wrapped in nonwoven fabric, as in Examples 1 to 12. Then, a mold rod containing the core material coated with the second activated carbon molding layer was placed in the mixed slurry for the intermediate activated carbon molding layer to form a coating for the intermediate activated carbon molding layer of a predetermined thickness on the surface of the coating for the second activated carbon molding layer. Next, a mold rod containing the core material coated with the second activated carbon molding layer and the intermediate activated carbon molding layer was placed in the mixed slurry for the first activated carbon molding layer to form a coating for the first activated carbon molding layer of a predetermined thickness on the surface of the coating for the intermediate activated carbon molding layer. The mold rod was removed from the core material, and an adsorbent adsorbent was obtained, which was an integrated product of the three coating layers (molded layers) and the core material.

[0064] In Comparative Examples 1 to 13, a mold rod with a core material wrapped in nonwoven fabric was placed in a mixed slurry of a predetermined ratio (unit: parts by weight) of activated carbon materials and binders, and a predetermined thickness of solid matter was applied to the surface of the core material to form an adherend. The mold rod was removed from the core material to obtain an adsorbent adherend, which was an integrated product of the single-layer adherend (molded layer) and the core material.

[0065] The resulting adsorbent materials of each prototype and comparative example were heated and dried at 100°C for 12 hours in a dryer to form layers of each adsorbent material, producing activated carbon filter bodies of each prototype and comparative example. Each activated carbon filter body was a cylinder with a diameter of 65 mm including the core and a total length of 60 mm. The materials used and the inner and outer diameters of each layer of the activated carbon filter bodies of each prototype and comparative example are shown in Tables 1 to 6 below.

[0066] [Activated carbon material] The activated carbon materials used were the following activated carbons A to E, which were made from coconut shells. 10 is the 10% particle size in the cumulative particle size distribution based on volume, D 50 is the 50% particle size in the cumulative particle size distribution based on volume, D 90 is the 90% particle size in the cumulative particle size distribution based on volume. Activated carbon A: Powdered activated carbon (manufactured by Futamura Chemical Co., Ltd.; "CN30MS"), 10 :14.5μm, D 50 :32.0μm, D 90 :55.6μm) Activated carbon B: Powdered activated carbon (manufactured by Futamura Chemical Co., Ltd.; "CN50MS"), 10 :17.7μm, D 50 :40.4μm, D 90 :77.0μm) Activated carbon C: Powdered activated carbon (manufactured by Futamura Chemical Co., Ltd.; "CN70MS"), 10 :25.3μm, D 50 :71.9μm, D 90 :151.6μm) Activated carbon D: Powdered activated carbon (manufactured by Futamura Chemical Co., Ltd.; "CN100MS") 10 :35.4μm, D 50 :93.0μm, D 90 :159.3μm) Activated carbon E: Powdered activated carbon (Futamura Chemical Co., Ltd.; "CN8200S") 10 :103.0μm, D 50 :147.4μm, D 90 :207.4μm)

[0067] [binder] As the binder, fibrillated acrylic resin fibers (manufactured by Nippon Exlan Kogyo Co., Ltd.; "Vipal (registered trademark)") were used.

[0068] [Prototype 1] Prototype example 1 is an activated carbon filter body consisting of a first activated carbon molding layer (outer layer) using activated carbon C and a second activated carbon molding layer (inner layer) using activated carbon B, with the outer layer having an inner diameter of 40 mm, an outer diameter of 65 mm, and a volume ratio of 85.5, and the inner layer having an inner diameter of 34 mm, an outer diameter of 40 mm, and a volume ratio of 14.5.

[0069] [Prototype 2] Prototype 2 is an activated carbon filter body that is the same as Prototype 1 except that the inner diameter of the outer layer is changed to 45 mm, the volume ratio is changed to 71.7, and the outer diameter of the inner layer is changed to 45 mm, the volume ratio is changed to 28.3.

[0070] [Prototype 3] Prototype 3 is an activated carbon filter body that is the same as Prototype 1 except that the inner diameter of the outer layer is changed to 50 mm, the volume ratio is changed to 56.2, and the outer diameter of the inner layer is changed to 50 mm, the volume ratio is changed to 43.8.

[0071] [Prototype 4] Prototype 4 is an activated carbon filter body that is the same as Prototype 1 except that the inner diameter of the outer layer is changed to 55 mm, the volume ratio is changed to 39.1, and the outer diameter of the inner layer is changed to 55 mm, the volume ratio is changed to 60.9.

[0072] [Prototype 5] Prototype 5 is an activated carbon filter body that is the same as Prototype 1 except that the inner diameter of the outer layer is changed to 60 mm, the volume ratio is changed to 20.4, and the outer diameter of the inner layer is changed to 60 mm, the volume ratio is changed to 79.6.

[0073] [Prototype 6] Prototype 6 is an activated carbon filter body that is the same as Prototype 1 except that the inner diameter of the outer layer is changed to 62 mm, the volume ratio is changed to 12.4, and the outer diameter of the inner layer is changed to 62 mm, the volume ratio is changed to 87.6.

[0074] [Prototype 7] Prototype 7 is an activated carbon filter body that is the same as Prototype 4 except that the activated carbon material in the inner layer is changed to activated carbon A.

[0075] [Prototype 8] Prototype 8 is an activated carbon filter body that is the same as Prototype 4 except that the activated carbon material for the outer layer is changed to activated carbon D and the activated carbon material for the inner layer is changed to activated carbon C.

[0076] [Prototype 9] Prototype 9 is an activated carbon filter body that is the same as Prototype 7 except that the activated carbon material in the outer layer is changed to activated carbon D.

[0077] [Prototype 10] Prototype 10 is an activated carbon filter body that is the same as Prototype 4 except that the activated carbon material for the outer layer is changed to activated carbon E and the activated carbon material for the inner layer is changed to activated carbon D.

[0078] [Prototype 11] Prototype 11 is an activated carbon filter body that is the same as Prototype 4 except that the activated carbon material in the outer layer is changed to activated carbon E.

[0079] [Prototype 12] Prototype example 12 is an activated carbon filter body in which the outer layer using activated carbon B has an inner diameter of 54 mm, an outer diameter of 65 mm, and a volume ratio of 42.7, and the inner layer using activated carbon C has an inner diameter of 34 mm, an outer diameter of 54 mm, and a volume ratio of 57.3.

[0080] [Prototype 13] Prototype example 13 is an activated carbon filter body consisting of a first activated carbon molding layer (outer layer) using activated carbon C, an intermediate activated carbon molding layer (middle layer) using activated carbon B, and a second activated carbon molding layer (inner layer) using activated carbon A, with the outer layer having an inner diameter of 57 mm, an outer diameter of 65 mm, and a volume ratio of 31.8, the middle layer having an inner diameter of 47 mm, an outer diameter of 57 mm, and a volume ratio of 34.9, and the inner layer having an inner diameter of 34 mm, an outer diameter of 47 mm, and a volume ratio of 34.3.

[0081] [Prototype 14] Prototype 14 is an activated carbon filter body that is the same as Prototype 13, except that the activated carbon material in the outer layer is changed to activated carbon D, the activated carbon material in the middle layer is changed to activated carbon C, and the activated carbon material in the inner layer is changed to activated carbon B.

[0082] [Table 1]

[0083] [Table 2]

[0084] [Table 3]

[0085] The following Comparative Examples 1 to 13 are activated carbon filter bodies having conventional structures, and are intended for comparison with Prototype Examples 1 to 14. The activated carbon material corresponding to the constituent material of the first activated carbon molding layer was selected as the first activated carbon material, the activated carbon material corresponding to the constituent material of the second activated carbon molding layer as the second activated carbon material, and the activated carbon material corresponding to the constituent material of the intermediate activated carbon molding layer as the third activated carbon material. The blending ratio (volume ratio) of each activated carbon material was the volume ratio of each layer of the corresponding prototype example.

[0086] [Comparative Example 1] Comparative Example 1, which was intended for comparison with Prototype Example 1, was an activated carbon filter body in which activated carbon C was used as the first activated carbon material and activated carbon B was used as the second activated carbon material, with activated carbon C and activated carbon B mixed in a volume ratio of 85.5:14.5, and which had an inner diameter of 34 mm and an outer diameter of 65 mm.

[0087] Comparative Example 2 Comparative Example 2 is an activated carbon filter body that is the same as Comparative Example 1, except that the volume ratio of the mixed activated carbon materials is changed to 71.7:28.3, in order to compare with Prototype Example 2.

[0088] Comparative Example 3 Comparative Example 3 was an activated carbon filter body that was the same as Comparative Example 1, except that the volume ratio of the mixed activated carbon materials was changed to 56.2:43.8, in order to compare with Prototype Example 3.

[0089] Comparative Example 4 Comparative Example 4 is an activated carbon filter body that is the same as Comparative Example 1, except that the volume ratio of the mixed activated carbon materials is changed to 39.1:60.9, in order to compare with Prototype Example 4.

[0090] Comparative Example 5 Comparative Example 5 is an activated carbon filter body that is the same as Comparative Example 1, except that the volume ratio of the mixed activated carbon materials is changed to 20.4:79.6, in order to compare with Prototype Example 5.

[0091] Comparative Example 6 Comparative Example 6 is an activated carbon filter body that is the same as Comparative Example 1, except that the volume ratio of the mixed activated carbon materials is changed to 12.4:87.6, in order to compare with Prototype Example 6.

[0092] Comparative Example 7 Comparative Example 7 is an activated carbon filter body that is the same as Comparative Example 4, except that the second activated carbon material is changed to activated carbon A, in order to be compared with Prototype Example 7.

[0093] [Comparative Example 8] Comparative Example 8 is an activated carbon filter body that is the same as Comparative Example 4, except that the first activated carbon material is changed to activated carbon D and the second activated carbon material is changed to activated carbon C, in order to compare with Prototype Example 8.

[0094] Comparative Example 9 Comparative Example 9 is an activated carbon filter body for comparison with Prototype Example 9, in which the first activated carbon material is changed to activated carbon D from Comparative Example 7, and the rest is the same.

[0095] [Comparative Example 10] Comparative Example 10 is an activated carbon filter body that is the same as Comparative Example 4, except that the first activated carbon material is changed to activated carbon E and the second activated carbon material is changed to activated carbon D, in order to compare with Prototype Example 10.

[0096] [Comparative Example 11] Comparative Example 11 is an activated carbon filter body for comparison with Prototype Example 11, in which the first activated carbon material is changed to activated carbon E from Comparative Example 4, and the rest is the same.

[0097] [Comparative Example 12] Comparative Example 12, intended for comparison with Prototype Example 13, is an activated carbon filter body having an inner diameter of 34 mm and an outer diameter of 65 mm, in which activated carbon C is used as the first activated carbon material, activated carbon B is used as the third activated carbon material, and activated carbon A is used as the second activated carbon material, with activated carbon C, activated carbon B, and activated carbon A mixed in a volume ratio of 31.8:34.9:34.3.

[0098] [Comparative Example 13] Comparative Example 13 was an activated carbon filter body that was the same as Prototype Example 12, except that the first activated carbon material was changed to activated carbon D, the second activated carbon material was changed to activated carbon C, and the third activated carbon material was changed to activated carbon B, in order to compare it with Prototype Example 14.

[0099] [Table 4]

[0100] [Table 5]

[0101] [Table 6]

[0102] To evaluate the performance of the activated carbon filter bodies of Prototype Examples 1 to 14 and Comparative Examples 1 to 13, the sum of the pore volumes (mL / g), mode diameters (μm), layer thicknesses (mm), chloroform filtration capacity (L), and turbidity filtration capacity (L) of each molded layer were measured. The results are shown in Tables 7 to 12 below.

[0103] [Gap volume sum] For each of the activated carbon filter bodies of Prototype Examples 1 to 14 and Comparative Examples 1 to 13, test pieces X1 and X2 each having a sectorial shape in plan view were cut out from the outer peripheral surface side and the inner peripheral surface side, respectively, as shown in Fig. 4. In Prototype Examples 1 to 14, the outer test piece X1 corresponds to the first activated carbon molding layer, and the inner test piece X2 corresponds to the second activated carbon molding layer, while in Comparative Examples 1 to 13, the outer test piece X1 corresponds to the outer peripheral side of the filter body, and the inner test piece X2 corresponds to the inner peripheral side of the filter body.

[0104] After thoroughly drying the test pieces X1 and X2 of each of Prototype Examples 1 to 14 and Comparative Examples 1 to 13, a mercury porosimeter (Micromeritics Corporation; pore size distribution measuring device "Autopore V9620") was used to measure the sum of pore volumes (mL / g) of test pieces with pore diameters of 5 to 15 μm and 15 to 40 μm by mercury intrusion porosimetry, with a contact angle of 130° and a surface tension of 485.0 dynes / cm. Furthermore, for each of Prototype Examples 1 to 14 and Comparative Examples 1 to 13, the sum of pore volumes (V a1 ) and the sum of the void volumes of specimen X2 (V a2 ) and the difference (V Da ) was calculated from the above formula (i), and the sum of the void volumes (V b1 ) and the sum of the void volumes of specimen X2 (V b2 ) and the difference (V Db ) was calculated from the above formula (ii).

[0105] [Mode diameter] For each of the test pieces X1 and X2 of the prototypes 1 to 14 and the comparative examples 1 to 13, the mode diameter (μm) of the gap diameter was determined from the gap distribution measured by mercury porosimetry. In addition, for each of the prototypes 1 to 14 and the comparative examples 1 to 13, the difference (M D ) was calculated from the above formula (iii).

[0106] [Layer thickness] For each of the prototypes 1 to 12, the thicknesses of the first activated carbon molding layer and the second activated carbon molding layer were calculated from the inner diameter and the outer diameter. Also, for each of the prototypes 1 to 12, the thickness ratio (T2) of the second activated carbon molding layer to the thickness (T1) of the first activated carbon molding layer was calculated. R ) was calculated from the above formula (iv).

[0107] [Chloroform filtration capacity] For each of the activated carbon filter bodies of Prototype Examples 1 to 14 and Comparative Examples 1 to 13, the chloroform filtration capacity (L) was measured to evaluate the adsorption performance for residual components. The chloroform filtration capacity was measured in accordance with the volatile organic compound filtration capacity test of the household water purifier testing method specified in JIS S 3201 (2019). For the measurement of chloroform filtration capacity, chloroform was prepared as test water to a concentration of 0.060±0.012 mg / L. Each activated carbon filter body was mounted in a stainless steel housing, and test water adjusted to 20°C was passed through the filter body at a flow rate of 2 L / min (SV value 830 hr -1 The sample water flowing through the activated carbon filter was collected and quantitatively measured for chloroform concentration using gas chromatography (Shimadzu Corporation, Gas Chromatograph GC-2014). The test water before and after passing through the activated carbon filter were compared, and the point at which the chloroform breakthrough rate in the outflow test water relative to the inflow test water was 20% or more was defined as the breakthrough point for the substance. The total volume of filtered water at the breakthrough point was defined as the chloroform filtration capacity (L).

[0108] [Turbidity filtration capacity] The turbidity filtration capacity (L) of the activated carbon filter bodies of each of Prototype Examples 1 to 14 and Comparative Examples 1 to 13 was measured. The turbidity filtration capacity was measured in accordance with the turbidity filtration capacity test method of the household water purifier testing method specified in JIS S 3201 (2019). In measuring the turbidity filtration capacity, kaolin (manufactured by Nacalai Tesque Inc.; "Nacalai Standard Class 1 EP (Extra Pure Reagent)") was prepared as test water to a concentration of 2.0±0.2 degrees. Each activated carbon filter body was mounted in a stainless steel housing, and test water adjusted to 20°C was passed through the filter at a flow rate of 2 L / min (SV value 830 hr -1 Water was passed through the filter at a flow rate of 100 sq. m / s, and the turbidity of the filtered water was measured after 10 minutes of continuous water passage. The ratio of the turbidity of the filtered water to the turbidity of the test water before passage was calculated as the turbidity removal rate (%), which was used to evaluate particle collection performance. The cumulative amount of water passed through the filter (L) until the filtration flow rate fell to half of the initial filtration flow rate was used to evaluate the turbidity filtration capacity (L), which was used to evaluate the resistance to clogging.

[0109] [Table 7]

[0110] [Table 8]

[0111] [Table 9]

[0112] [Table 10]

[0113] [Table 11]

[0114] [Table 12]

[0115] [Filtration capacity ratio] The chloroform filtration capacity and turbidity filtration capacity of Prototype Examples 1 to 14 were compared with those of the corresponding Comparative Examples 1 to 13, and the ratio of each filtration capacity (L) of each Prototype Example to the filtration capacity (L) of the Comparative Examples was calculated, and the resulting value was designated as the filtration capacity ratio (%) of each filtration capacity of Prototype Examples 1 to 14. Tables 13 to 15 below show the measured chloroform filtration capacity (L) of each Prototype Example 1 to 14, the relative value (L) measured for the corresponding Comparative Example, the filtration capacity ratio (%), the measured turbidity filtration capacity (L), the relative value (L) measured for the corresponding Comparative Example, and the filtration capacity ratio (%). Note that Prototype Example 12 was compared with Comparative Example 3, which uses a similar volume ratio of activated carbon materials.

[0116] [Table 13]

[0117] [Table 14]

[0118] [Table 15]

[0119] [Results and Discussion] First, we will consider the activated carbon filter bodies of Prototypes 1 to 12. As can be seen from Tables 13 and 14, the chloroform filtration capacity of Prototypes 1 to 12 was almost 100% in all cases, and they exhibited adsorption performance comparable to that of conventional activated carbon filter bodies. This indicates that the adsorption performance for residual components is not affected by the structure of the molded body, but is influenced by the proportion of activated carbon material in the filter body.

[0120] The turbidity removal rates of prototypes 1 to 12 all demonstrated performance equivalent to that of conventional activated carbon filters. Of these prototypes, prototype 10 had a turbidity removal rate of 80% or less from the early stages of water flow, so it was determined that the turbidity filtration capacity could not be measured using the aforementioned test method (JIS S 3201) and that the required particle collection performance was not achieved. On the other hand, prototypes 1 to 9, 11, and 12 had turbidity removal rates of 95% or more, demonstrating excellent particle collection performance.

[0121] Regarding the turbidity filtration capacity of prototypes 1 to 12, the filtration capacity ratios of prototypes 1 to 9 were significantly higher than 100%, while the filtration capacity ratios of prototypes 11 and 12 were significantly lower than 100%. The prototypes 1 to 9 with good turbidity filtration capacity were those with a difference in the sum of the pore volumes of the pores with a diameter of 5 to 15 μm between the outer and inner layers (V Da ) and the difference between the sum of the void volumes of voids with diameters of 15 to 40 μm (V Db ), the outer layer has many relatively large gaps (gap diameter 15 to 40 μm), while the inner layer has many relatively small gaps (gap diameter 5 to 15 μm).

[0122] On the other hand, in prototype 12, which has a low filtration capacity ratio, the activated carbon material in the outer layer (activated carbon B) and the activated carbon material in the inner layer (activated carbon C) are interchanged with the activated carbon material in the outer layer (activated carbon C) and the activated carbon material in the inner layer (activated carbon B) in prototypes 1 to 6. Therefore, in prototype 12, the difference in the sum of the void volumes (V Da ) and (V Db ), the outer layer has many relatively small gaps (gap diameter 5-15 μm), while the inner layer has many relatively large gaps (gap diameter 15-40 μm). Therefore, it is thought that the activated carbon filter body has a structure in which the outer layer has many relatively large gaps (gap diameter 15-40 μm) and the inner layer has many relatively small gaps (gap diameter 5-15 μm), which gives it a property of being less likely to clog.

[0123] Thus, in prototypes 1 to 9, both the turbidity removal rate and the turbidity filtration capacity were good, that is, a high level of particle collection performance (turbidity removal rate) and clogging resistance (turbidity filtration capacity) were achieved. In contrast, in prototypes 10 to 12, at least one of the turbidity removal rate and the turbidity filtration capacity was insufficient, that is, a high level of particle collection performance (turbidity removal rate) and clogging resistance (turbidity filtration capacity) could not be achieved. Therefore, considering the configuration and measurement results of each molding layer of prototypes 1 to 12, the preferable conditions for achieving a high level of particle collection performance and clogging resistance were examined. The outer layer had a void volume sum (V a1 ) is about 0.30 to 0.75 mL / g and the sum of the pore volumes (V b1 ) is about 0.45 to 1.10 mL / g, and the inner layer is the sum of the pore volumes (V a2 ) is about 0.80 to 1.20 mL / g and the sum of the pore volumes (V b2 ) is less than about 0.40 mL / g, and the relationship between the outer layer and the inner layer is the difference in the sum of the void volumes of voids with a diameter of 5 to 15 μm (V Da ) is about -0.70 to -0.05 mL / g, and the difference in the sum of the pore volumes of pores with a diameter of 15 to 40 μm (V Db ) should be approximately 0.05 to 1.10 mL / g.

[0124] Next, the filtering capacity ratio of turbidity filtering capacity (resistance to clogging) will be compared between Prototypes 1 to 6 and Comparative Examples 1 to 6. Prototypes 1 to 6 have a relationship in which the layer thickness (T2) of the inner layer increases relative to the layer thickness (T1) of the outer layer, that is, the layer thickness ratio (T R ) increases in this order (see Table 1). On the other hand, Comparative Examples 1 to 6 are examples in which the blending ratio (volume ratio) of the activated carbon material is set to correspond to the volume ratio of the activated carbon material constituting the outer layer and the inner layer of Prototype Examples 1 to 6 (see Table 4).

[0125] In Comparative Examples 1 to 6, as can be seen from Tables 4 and 10, the turbidity filtration capacity (L) tended to decrease as the blending ratio of the first activated carbon material (activated carbon C) decreased. On the other hand, in Prototype Examples 1 to 6, although the turbidity filtration capacity (L) of Prototype Examples 5 and 6 was slightly decreased compared to Prototype Examples 1 to 4, the turbidity filtration capacity (L) tended to be maintained at roughly the same level. In particular, while the turbidity filtration capacity (L) of Comparative Examples 1 to 6 tended to decrease, the turbidity filtration capacity (L) of Prototype Examples 1 to 6 was almost maintained, which indicates that the layer thickness ratio (T R As the value of ) increases, the filtration capacity ratio (%) tends to increase.

[0126] As described above, in Comparative Examples 1 to 6, which have a single-layer structure in which different activated carbon materials are mixed, it was difficult to ensure a high level of clogging resistance. On the other hand, in Prototype Examples 1 to 6, the outer layer and the inner layer (V a1 )(V b1 )(V a2 )(V b2 ) is composed of different activated carbon molding layers that satisfy the specified conditions, and the difference between the sum of the void volumes of the outer layer and the inner layer (V Da ) and (V Db ) as described above, it was possible to significantly improve the resistance to clogging compared to conventional methods. In particular, since the filtration capacity ratio exceeds 200% in prototypes 4 to 6, this structure ensures a high level of resistance to clogging.

[0127] Prototypes 10 and 11 are examples in which activated carbon E is used in the outer layer. Prototype 10 is configured by changing the outer layer from Prototype 4 to activated carbon E and the inner layer to activated carbon D, while Prototype 11 is configured by changing the outer layer from Prototype 4 to activated carbon E. The outer layers of Prototypes 10 and 11 have a mode diameter of 39.4 μm (see Table 8), which indicates that particularly large particles are targeted for collection. Therefore, it is thought that in Prototype 11, only a limited number of particles are removed on the outer layer side, and many of the particles that are not removed are captured on the inner layer side, making clogging more likely to occur. Furthermore, in Prototype 10, the mode diameter of the inner layer is 16.4 μm, which means that the particles targeted for collection in the inner layer are larger than in Prototype 4. This suggests that the particles removed on both the outer and inner layer sides are limited, resulting in a significant decrease in particle collection performance.

[0128] Samples 13 and 14 are examples of activated carbon filter bodies with a three-layer structure consisting of an outer layer (first activated carbon molded layer), a middle layer (third activated carbon molded layer), and an inner layer (second activated carbon molded layer). As shown in Table 15, Samples 13 and 14, like Samples 1 to 9 with a two-layer structure, have particle collection performance comparable to that of Comparative Examples 12 and 13, and a high level of resistance to clogging. As can be seen from Table 9, Samples 13 and 14, like Samples 1 to 9, were able to achieve both particle collection performance and resistance to clogging by satisfying a predetermined relationship between the outer layer (first activated carbon molded layer) and the inner layer (second activated carbon molded layer). [Industrial Applicability]

[0129] As described above, the activated carbon filter body of the present invention has a structure in which the filter medium is composed of a first activated carbon layer and a second activated carbon layer with different properties, which allows particles in a liquid to be removed in stages according to their size, thereby achieving both high levels of particle collection performance and low clogging resistance, making it a promising alternative to conventional activated carbon filters. [Explanation of symbols]

[0130] 10 Activated carbon filter body 11 Filter media section 12 Side of filter element 13 Hollow part 14 Core material 15 First activated carbon forming layer 16 Second activated carbon forming layer D Water flow direction P1,P1a,P1b particles P2 particles X1, X2 test pieces

Claims

1. A filter body having a hollow cylindrical filter medium portion containing an activated carbon material and a binder, The filter portion has a first activated carbon layer formed of one activated carbon material and arranged upstream in the filtration direction, and a second activated carbon layer formed of another activated carbon material and arranged downstream in the filtration direction, The sum of the void volumes (V ａ１ ) is 0.30 to 0.75 mL / g, and the sum of the void volumes (V ｂ１ ) is 0.45 to 1.10 mL / g, The sum of the void volumes (V ａ２ ) is 0.80 to 1.20 mL / g, and the sum of the void volumes (V ｂ２ ) is 0.40 mL / g or less, The sum of the void volumes (V ａ１ ) and the sum of the void volumes of voids with a diameter of 5 to 15 μm in the second activated carbon molding layer (V ａ２ ) and the difference (V Ｄａ ) is -0.70 to -0.05 mL / g, and the sum of the void volumes (V ｂ１ ) and the sum of the void volumes of voids with a diameter of 15 to 40 μm in the second activated carbon molding layer (V ｂ２ ) and the difference (V Ｄｂ ) is 0.05 to 1.10 mL / g Activated carbon filter body characterized by: (V Ｄａ )=(V ａ１ )-(V ａ２ ) … (i) (V Ｄｂ )=(V ｂ１ )-(V ｂ２ ) … (ii)

2. The pore mode diameter (M １ ) is 15 to 25 μm, and the pore mode diameter (M ２ 2. The activated carbon filter body according to claim 1, wherein the particle size is 5 to 15 μm.

3. The void mode diameter (M １ ) and the gap mode diameter (M ２ ) and the difference (M Ｄ 3. The activated carbon filter body according to claim 2, wherein the particle size is 5 to 15 μm. (M Ｄ )=(M １ )-(M ２ ) … (iii)

4. The thickness of the first activated carbon layer (T １ ) to the layer thickness (T ２ ) the layer thickness ratio (T Ｒ 4. The activated carbon filter body according to claim 1, wherein the value of (A) is 0.24 to 9.

33. (T Ｒ )=(T ２ ) / (T １ ) … (iv)

5. 4. The activated carbon filter body according to claim 1, wherein the first activated carbon molded layer and the second activated carbon molded layer are both made of wet-molded bodies.

6. 5. The activated carbon filter body according to claim 4, wherein the first activated carbon molded layer and the second activated carbon molded layer are both made of wet molded bodies.

Images