JP7500896B2 - Filtration Cartridge - Google Patents

Description

This invention relates to a filtration cartridge.

Conventionally, filtration cartridges using roll filters, thread-wound filters, spun-type filters, etc. have been used to treat water with a high solid concentration. Such filters are generally cylindrical, and water is treated by passing water between the outer and inner surfaces (for example, Patent Document 1).

JP 2016-22399 A

On the other hand, functional materials such as layered double hydroxides, zeolites, and activated carbon can adsorb and remove harmful substances from aqueous solutions. Therefore, if these functional materials are incorporated into the filters of filtration cartridges to give them functionality such as the ability to adsorb pollutants, they can be used for even more efficient contaminated water treatment.

Here, the treatment of contaminated water with functional materials requires control of the permeation time to adequately adsorb contaminants. However, water treatment with the above-mentioned filter is performed by passing water between the outer peripheral surface and the inner peripheral surface, and this distance is short, which poses the problem of insufficient permeation time. In order to ensure a sufficient distance, it is conceivable to change the size of the filter and the distance between the outer peripheral surface and the inner peripheral surface. However, there are standards for the size of the container in which the filtration cartridge is placed, so changing the size of the filter is not easy. In addition, there is a problem in that the amount of treatment decreases when the permeation speed is reduced to ensure the permeation time.

The present invention aims to provide a filtration cartridge that can ensure processing time even if it is the same size as a conventional filter.

The present invention is a filtration cartridge comprising a filter containing a functional material, and a low water permeability section that is made of a material that is less water permeable than the filter and is formed between one end of the outer peripheral surface of the filter and the other end of the inner peripheral surface to allow water to pass through.

In this case, the low water permeability portion is a member covering the surface of the filter, and the member may have a first water permeable portion formed on one end side of the outer peripheral surface of the filter, and a second water permeable portion formed on the other end side of the inner peripheral surface of the filter.

The member may be a non-permeable film, and may be composed of a first film that covers the surface of one end of the filter, including holes that communicate with the inner circumferential surface, a second film that covers the surface of the other end of the filter with holes that communicate with the inner circumferential surface, an outer circumferential film that covers the outer circumferential surface of the filter such that the first permeable portion is formed between the outer circumferential surface and the first film, and an inner circumferential film that covers the inner circumferential surface of the filter such that the second permeable portion is formed between the inner circumferential surface and the second film.

The member may also be composed of a cap that covers the surface of one end of the filter, including a hole that communicates with the inner peripheral surface, a container body that covers the outer peripheral surface of the filter so that the first water-permeable portion is formed between the cap and the container body, and covers the surface of the other end of the filter with a hole that communicates with the inner peripheral surface, and an inner plug that covers the inner peripheral surface of the filter so that the second water-permeable portion is formed between the container body and the cap.

In this case, the cap and the inner plug may be integrally formed.

The functional material used in the filtration cartridge can be at least one of layered double hydroxide, zeolite, and activated carbon.

According to the present invention, a material with lower permeability than the filter is used for the low-permeability portion, so processing time can be secured.

FIG. 2 is a perspective view showing a filter in the filtration cartridge of the present embodiment. FIG. 2 is a cross-sectional view showing the filtration cartridge of the present embodiment. 4 is a perspective view showing a manufacturing method of the filtration cartridge of the present embodiment. FIG. FIG. 4 is a cross-sectional view showing another filtration cartridge of the present embodiment. FIG. 4 is a cross-sectional view showing another filtration cartridge of the present embodiment. FIG. 11 is a cross-sectional view showing a filtration cartridge according to a modified example. 7(a) is a cross-sectional view of a filtration device to which the filtration cartridge of FIG. 6 can be attached, and FIG. 7(b) is an exploded view of the filtration device of FIG. 7(a).

The filtration cartridge of the present invention will be described with reference to Figures 1 to 5. The filtration cartridge of this embodiment is mainly composed of a filter 1 and a low water permeability section 2.

In this embodiment, the filter 1 is a cylindrical object containing a functional material, and is used to perform water treatment by passing liquid such as contaminated water between the outer peripheral surface and the inner peripheral surface. As shown in FIG. 1, for example, the filter 1 has an outer peripheral surface 11, an inner peripheral surface 12, a surface 13 on one end side (the upper surface on the paper in FIG. 1), and a surface 14 on the other end side (the lower surface on the paper in FIG. 1).

Examples of such filters that can be used include roll filters made by winding a sheet 6 of paper or nonwoven fabric around a rod-shaped winding section 5 into a roll, thread-wound filters made by winding thread around a winding section, and spun-type filters made by thermally fusing resin fibers.

The functional material refers to a material that can adsorb and remove harmful substances contained in contaminated water. In particular, the cartridge of this embodiment is useful when using a functional material that requires a certain processing time for the adsorption. Examples of functional materials include adsorbents such as layered double hydroxides, zeolites, and activated carbon. In addition, the functional material may be a single adsorbent, or multiple types of adsorbents may be used simultaneously.

The layered double hydroxide is a non-stoichiometric compound represented by the general formula M2 ⁺ _1- ^xM3 + _x (OH) ₂ ( ^An- ) _{x/ n.mH2O} (where M2 ⁺ is a divalent metal, M3 ⁺ is a trivalent metal, ^An- is an n-valent anion, 0<x<1, m>0), and is sometimes called a hydrotalcite-like compound. Examples of the divalent metal ion (M2 ⁺ ) include Mg2 ⁺ , Fe2 ⁺ , Zn2 ⁺ , Ca2 ⁺ , Li2 ⁺ , Ni2 ⁺ , Co2 ⁺ , and Cu2 ⁺ . Examples of the trivalent metal ion (M3 ⁺ ) include Al3 ⁺ , Fe3 ⁺ , Cr3 ⁺ , and ^Mn3+ . Examples of anions (A ^n- ) include ClO ₄ ^- , CO ₃ ^2- , HCO ₃ ^- , PO ₄ ^3- , SO ₄ ^2- , SiO ₄ ^4- , OH ^- , Cl ^- , NO _2- ^, NO _3- ^, etc. The divalent metal ion (M ²⁺ ) and trivalent metal ion (M ³⁺ ) contained in the general formula do not have to be of one type, and may contain multiple types.

The layered double hydroxide according to this embodiment may use any divalent metal ion (M ²⁺ ), any trivalent metal ion (M ³⁺ ), or any anion (A ⁿ⁻ ). For example, the metal ion may be ^{Mg2 +} _1- ^xAl3+ _x (OH) ₂ (A ^n- ) _{x/ n.mH2O} (Mg ^- Al type) where the divalent metal ion (M2 ⁺ ) is Mg2 ⁺ and the trivalent metal ion (M3 ⁺ ) is ^Al3+ , Mg2 ⁺ _1- xFe3 ⁺ _x (OH)2(A n-) _{x/n.mH2O (Mg-Fe type) where the divalent metal ion (M2+) is Mg2+ and the trivalent metal ion (M3+) is Fe3+, or Fe2+1-xFe3+x(OH)2(A n-)x/} ^{n.mH2O ( Fe} _- ^Fe _{type )} ^where _{the divalent} metal ion ( ^{M2 +} ) is _Fe2 ⁺ and the trivalent metal ion (M3 ⁺ ) is _Fe3 ⁺ . The Mg-Fe type is superior to the Mg-Al type in that it is more effective at adsorbing arsenic, has a higher specific gravity and is therefore easier to separate by settling, and can reduce raw material costs.

The layered double hydroxide according to this embodiment preferably has a crystallite size of 20 nm or less, more preferably 10 nm or less. It is also preferable that the average crystallite size is 10 nm or less.

The specific surface area of the layered double hydroxide according to this embodiment is not particularly limited, but a larger specific surface area is preferable in terms of improving the adsorption performance. The layered double hydroxide may have a specific surface area of 20 m ² /g or more, preferably 30 m ² /g or more, more preferably 50 m ² /g or more, and even more preferably 70 m ² /g or more, as measured by the BET method. The upper limit of the specific surface area is not particularly limited. The specific surface area as measured by the BET method can be determined, for example, by measuring the nitrogen adsorption/desorption isotherm using a specific surface area/pore distribution measuring device and creating a BET-plot from the measurement results. For example, if the crystallite size of the layered double hydroxide is 20 nm or less, the specific surface area can be 20 m ² /g or more.

The synthesis of layered double hydroxides is carried out by mixing an acidic solution containing divalent metal ions and trivalent metal ions with an alkaline solution. The smaller the crystallite size of the layered double hydroxide synthesized here, the larger its specific surface area can be. Therefore, the shorter the aging time after synthesis, the better, and it is better to neutralize within at least 120 minutes, preferably within 60 minutes, after mixing the acidic solution and the alkaline solution, and even more preferably, immediately after mixing.

Next, as an example, a method for synthesizing a layered double hydroxide represented by the structural formula Mg ²⁺ _1-x Al ³⁺ _x (OH) ₂ (A ^n- ) _x/n ·mH ₂ O will be described.

First, prepare an acidic solution containing aluminum ions and magnesium ions.

The aluminum source for the aluminum ions is not limited to any particular substance, as long as it generates aluminum ions in water. For example, alumina, sodium aluminate, aluminum hydroxide, aluminum chloride, aluminum nitrate, bauxite, alumina production residue from bauxite, aluminum sludge, etc. can be used. Furthermore, any of these aluminum sources may be used alone, or two or more types may be used in combination.

The magnesium source of magnesium ions is not limited to any specific substance, as long as it generates magnesium ions in water. For example, brucite, magnesium hydroxide, magnesite, baked magnesite, etc. can be used. These magnesium sources can be used alone or in combination of two or more types.

The aluminum compound as the aluminum source and the magnesium compound as the magnesium source do not need to be completely dissolved as long as aluminum ions and magnesium ions are present in the acidic solution.

It is also known that a highly crystalline layered double hydroxide represented by Mg2 ⁺ _1- ^xAl3+ _x (OH) ₂ ( ^An- ) _{x/n.mH2O has} a molar ratio of aluminum ions to magnesium ions of 1:3 (x=0.25). Therefore, the molar ratio of aluminum ions to magnesium ions in the acidic solution is preferably in the range of 1:5 to 1:2. By setting the ratio in this range, the layered double hydroxide can be produced advantageously in terms of material balance without wasting the aluminum source and the magnesium source.

The acid contained in the acidic solution is not particularly limited as long as it makes the aqueous solution acidic, but for example, nitric acid or hydrochloric acid can be used.

An alkaline solution is also prepared. The alkali contained in the alkaline solution is not particularly limited as long as it makes the aqueous solution alkaline, but for example, sodium hydroxide, calcium hydroxide, etc. can be used. Sodium carbonate, potassium carbonate, ammonium carbonate, aqueous ammonia, sodium borate, potassium borate, etc. can also be used. Any of these may be used alone, or two or more types may be used in combination. The alkaline solution may be adjusted to a pH of 8 to 14, and preferably to a pH of 8 to 11.

Next, an acidic solution containing aluminum ions and magnesium ions is mixed with an alkaline solution containing an alkali in a predetermined ratio. This produces a layered double hydroxide. The mixing can be done by adding the acidic solution to the alkaline solution all at once or by dropping the acidic solution into the alkaline solution, but other methods are also possible.

The shorter the maturation time after the mixing of the acidic and alkaline solutions is completed, the more the crystal growth can be suppressed, and layered double hydroxides with small crystallite sizes and large specific surface areas can be produced.

As a method for stopping the aging, after the mixing of the acidic solution and the alkaline solution is completed, the pH of the mixed solution may be lowered to a value at which the crystal growth of the layered double hydroxide stops. For example, in the case of a layered double hydroxide represented by the general formula Mg ²⁺ _1-x Al ³⁺ _x (OH) ₂ (A ^n- ) _x/n ·mH ₂ O, the pH may be adjusted to 9 or less. Specifically, the aging can be stopped by diluting with water within 120 minutes, preferably within 60 minutes, and more preferably simultaneously with the mixing after the mixing of the acidic solution and the alkaline solution is completed. In order to ensure that the aging does not occur, it is also good to wash the layered double hydroxide promptly after the mixing of the acidic solution and the alkaline solution is completed. It is also possible to contain chlorides such as NaCl generated during the synthesis process.

In the above explanation, the case where aluminum ions and magnesium ions are contained in the acidic solution side has been described, but this is not limited to this. It is also possible to have aluminum ions contained in the acidic solution side and magnesium ions contained in the alkaline solution side, to have magnesium ions contained in the acidic solution side and aluminum ions contained in the alkaline solution side, or to have both aluminum ions and magnesium ions contained in the alkaline solution side.

As another example, a method for synthesizing a layered double hydroxide having a structural formula of Mg ²⁺ _1-x Fe ³⁺ _x (OH) ₂ (A ^n- ) _x/n ·mH ₂ O will be described.

First, prepare an acidic solution containing iron ions and magnesium ions.

The iron source of iron ions is not limited to a specific substance, as long as it generates iron ions in water. For example, iron chloride can be used. These iron sources can be used alone or in combination of two or more.

The magnesium source of magnesium ions is not limited to any specific substance, as long as it generates magnesium ions in water. For example, brucite, magnesium hydroxide, magnesite, baked magnesite, etc. can be used. These magnesium sources can be used alone or in combination of two or more types.

The iron compound as the iron source and the magnesium compound as the magnesium source do not need to be completely dissolved as long as iron ions and magnesium ions are present in the acidic solution.

It is also known that a highly crystalline layered double hydroxide represented by Mg2 ⁺ _1- ^xFe3+ _x (OH) ₂ ( ^An- ) _{x/n.mH2O has} a molar ratio of iron ions to magnesium ions of 1:3 (x=0.25). Therefore, the molar ratio of iron ions to magnesium ions in the acidic solution is preferably in the range of 1:5 to 1:2. By setting the molar ratio in this range, the layered double hydroxide can be produced in an advantageous manner in terms of material balance without wasting the iron source and magnesium source.

The acid contained in the acidic solution is not particularly limited as long as it makes the aqueous solution acidic, but for example, nitric acid or hydrochloric acid can be used.

An alkaline solution is also prepared. The alkali contained in the alkaline solution is not particularly limited as long as it makes the aqueous solution alkaline, but for example, sodium hydroxide, calcium hydroxide, etc. can be used. Sodium carbonate, potassium carbonate, ammonium carbonate, aqueous ammonia, sodium borate, potassium borate, etc. can also be used. Any of these may be used alone, or two or more types may be used in combination. The alkaline solution may be adjusted to a pH of 8 to 14, and preferably to a pH of 8 to 11.

Next, the acidic solution containing iron ions and magnesium ions is mixed with an alkaline solution containing an alkali in a predetermined ratio. This produces a layered double hydroxide. The mixing can be performed by adding the acidic solution to the alkaline solution all at once or by dropping the acidic solution into the alkaline solution, but other methods are also acceptable.

The shorter the maturation time after the mixing of the acidic and alkaline solutions is completed, the more the crystal growth can be suppressed, and layered double hydroxides with small crystallite sizes and large specific surface areas can be produced.

As a method for stopping the aging, after the mixing of the acidic solution and the alkaline solution is completed, the pH of the mixed solution may be lowered to a value at which the crystal growth of the layered double hydroxide stops. For example, in the case of a layered double hydroxide represented by the general formula Mg ²⁺ _1-x Fe ³⁺ _x (OH) ₂ (A ^n- ) _x/n ·mH ₂ O, the pH may be adjusted to 9 or less. Specifically, the aging can be stopped by diluting with water within 120 minutes, preferably within 60 minutes, and more preferably simultaneously with the mixing after the mixing of the acidic solution and the alkaline solution is completed. In order to ensure that the aging does not occur, it is also good to wash the layered double hydroxide promptly after the mixing of the acidic solution and the alkaline solution is completed. It is also possible to include chlorides such as NaCl generated during the synthesis process.

In the above explanation, the case where the acidic solution contains iron ions and magnesium ions has been described, but this is not limited to the above. It is also possible to have the acidic solution contain iron ions and the alkaline solution contain magnesium ions, to have the acidic solution contain magnesium ions and the alkaline solution contain iron ions, or to have the alkaline solution contain both iron ions and magnesium ions.

Zeolite is a general term for crystalline aluminosilicates with micropores of about 0.4 nm to 2 nm in the crystals. Zeolite is a complex oxide with a three-dimensional network structure in which Si-O tetrahedrons and Al-O tetrahedrons share O atoms at their vertices, and can adsorb and remove target cations by ion exchange with exchangeable cations (Na ⁺ and K ⁺ ) contained within the zeolite.

Zeolites include ZSM-5 type zeolite, faujasite type zeolite, mordenite type zeolite, L type zeolite, A type zeolite, X type zeolite, Y type zeolite, etc., and any of these can be used. Zeolite-like compounds such as clinobutilite, mordenite, and synthetic zeolites also have functions equivalent to those of zeolites and can be used as functional materials. The type of zeolite can be appropriately selected taking into consideration the target to be treated by the functional material according to this embodiment.

Activated carbon is a substance whose main component is porous carbon that has been chemically or physically treated to increase its adsorption efficiency for the purpose of selectively removing specific substances.

When it is desired to produce a paper sheet containing a functional material, papermaking can be performed using a mixed solution containing the functional material and paper or paper fibers. In this case, a binder can also be used to fix the functional material to the paper fibers. For example, the mixed solution is first spread on a net or papermaking blind. The water then passes through the net or papermaking blind and falls, while the functional material such as layered double hydroxide and the paper or paper fibers remain on the net or papermaking blind. If the water is removed from this and it is dried in a drying process, a sheet of paper can be produced. Note that the specific means for papermaking, water removal, and drying can be well-known methods. Note that the mixed solution can be prepared by separately preparing the functional material and the paper or paper fibers and then mixing them, but it is also possible to use a solution in which the functional material is synthesized in the presence of paper or paper fibers.

Specifically, for example, when it is desired to produce a paper sheet containing a layered double hydroxide, papermaking can be carried out using a mixed solution containing the layered double hydroxide and paper or paper fibers. In this case, a binder can be used to fix the layered double hydroxide to the paper fibers. In addition, the layered double hydroxide and paper or paper fibers can be separately prepared and then mixed to prepare the mixed solution, or a solution prepared by synthesizing the layered double hydroxide in the presence of paper or paper fibers can be used.

In addition, when it is desired to manufacture a sheet of nonwoven fabric or the like containing a functional material, the functional material may be mixed with fibers for nonwoven fabric in a conventionally known manufacturing process for nonwoven fabric, such as a dry method, a wet method, a spunbond method, or a meltblown method. In this case, a binder may be used to fix the functional material to the fibers for nonwoven fabric. The functional material and the fibers for nonwoven fabric may be prepared separately and then mixed, or a functional material synthesized in the presence of the fibers may be used. For example, when it is desired to manufacture a sheet of nonwoven fabric containing a layered double hydroxide, the nonwoven fabric may be manufactured using a mixed solution containing the layered double hydroxide and fibers for nonwoven fabric. In this case, a binder may be used to adhere the layered double hydroxide to the nonwoven fabric.

The low water permeability section 2 only needs to have a lower water permeability than the filter 1. In this embodiment, a non-permeable material is used, and the low water permeability section 2 is formed to be water permeable between one end side of the outer peripheral surface 11 of the filter 1 and the other end side of the inner peripheral surface 12. For example, as shown in FIG. 2, the low water permeability section 2 is a member that covers the surface of the filter 1, and the member may be configured to have a first water permeable section 3 formed on one end side of the outer peripheral surface 11 of the filter 1 and a second water permeable section 4 formed on the other end side of the inner peripheral surface 12 of the filter 1. This allows liquid such as contaminated water to be supplied from either the first water permeability section 3 or the second water permeability section 4, and the filtered liquid to be discharged from the other. The area of the first water permeability section 3 is preferably half or less, preferably one quarter or less, of the area of the outer peripheral surface 11. The area of the second water permeability section 4 is preferably half or less, preferably one quarter or less, of the area of the inner peripheral surface 12. In addition, by adjusting the area of the first water permeable portion 3 and the area of the second water permeable portion 4, the speed of liquid such as contaminated water flowing through the filter 1 can be adjusted. Specifically, when the area of the first water permeable portion 3 is made larger than the area of the second water permeable portion 4 and liquid is caused to flow from the first water permeable portion 3 to the second water permeable portion 4 at a predetermined pressure, the flow rate of the liquid on the second water permeable portion 4 side can be made larger than the flow rate of the liquid on the first water permeable portion 3 side. Conversely, when the area of the first water permeable portion 3 is made smaller than the area of the second water permeable portion 4 and liquid is caused to flow from the first water permeable portion 3 to the second water permeable portion 4 at a predetermined pressure, the flow rate of the liquid on the second water permeable portion 4 side can be made smaller than the flow rate of the liquid on the first water permeable portion 3 side.

Here, the non-permeable material has a permeability coefficient of ^10-4 to ^10-9 cm/s, preferably ^10-7 to ^10-9 cm/s, and any material that is not easily deteriorated by components of liquids such as contaminated water can be used, for example, polypropylene.

As an example of a member made of a non-permeable material, a non-permeable film 21 may be used. It is preferable to use a film that is not permeable to liquids but is permeable to gases as the non-permeable film 21. In this case, the member is mainly composed of a first film 213 covering the surface 13 on one end side of the filter 1, a second film 214 covering the surface 14 on the other end side of the filter 1, an outer film 211 covering the outer surface 11 of the filter 1, and an inner film 212 covering the inner surface 12 of the filter 1.

The first film 213 covers the surface 13 (upper surface) on one end side of the filter 1, including the holes 15 that communicate with the inner circumferential surface 12, and is formed so as not to allow liquids such as contaminated water to pass through the surface 13 on one end side of the filter 1 and the openings of the holes 15 that communicate with the inner circumferential surface 12 of the filter 1. The first film 213 may be formed in a shape that is the same as the outer diameter of the filter 1, or at least larger than that circle.

The second film 214 covers the surface 14 (lower surface) on the other end side of the filter 1 with a hole 16 that communicates with the inner circumferential surface 12, and is formed so as not to allow liquids such as contaminated water to pass through the surface 14 on the other end side of the filter 1 except for the hole 16. The second film 214 has a hole 215 that communicates with the inner circumferential surface 12, and may be formed in a shape that is at least the same as the outer diameter of the filter 1 or larger than the circle. It is preferable that the hole 215 has the same diameter as the hole 16 formed by the inner circumferential surface 12 of the filter 1.

The peripheral film 211 covers the peripheral surface 11 of the filter 1 so that a first water-permeable portion 3 is formed between the peripheral film 211 and the first film 213, and is formed so as not to allow liquids such as contaminated water to pass through the peripheral surface 11 of the filter 1. The peripheral film 211 may be formed in a quadrangle having a side that is shorter than the axial length of the filter 1 (the vertical direction in FIG. 1) by the length of the first water-permeable portion 3, and a side that is longer than the periphery of the filter 1.

The inner film 212 covers the inner surface 12 of the filter 1 so that a second water-permeable portion 4 is formed between the inner film 212 and the second film 214, and is formed so as not to allow liquids such as contaminated water to pass through the inner surface 12 of the filter 1. The inner film 212 may be formed in a quadrangle having a side that is shorter than the axial length of the filter 1 by the length of the second water-permeable portion 4 and a side that is longer than the outer circumference of the hole 15 of the filter 1.

The first film 213, the second film 214, the outer peripheral film 211, and the inner peripheral film 212 may be made of the same material or different materials, as long as they are non-permeable materials.

The filtration cartridge of this embodiment may be manufactured in any manner, but for example, a roll filter can be manufactured by the following method.

First, prepare a sheet 6 for the filter 1, such as paper or nonwoven fabric containing a functional material. Also prepare an inner film 212 whose width is smaller than the width of the short side of the sheet 6 by the width of the second water-permeable section 4, and an outer film 211 whose width is smaller than the width of the short side of the sheet 6 by the width of the first water-permeable section 3.

Next, as shown in Figs. 3(a) to 3(d), the inner periphery film 212, the sheet 6, and the outer periphery film 211 are wound around the rod-shaped winding section 5 in this order. At this time, in order to form the second water-permeable section 4, the sheet 6 is wound with one end 212a of the inner periphery film 212 aligned with one end 6a of the long side of the sheet 6 as shown in Fig. 3(b). In addition, in order to form the first water-permeable section 3, the outer periphery film 211 is wound with the other end 6b of the long side of the sheet 6 aligned with the other end 211b of the outer periphery film 211 as shown in Fig. 3(c). Then, as shown in Fig. 3(d), the very end of the outer periphery film 211 is attached to the surface of the wound sheet 6 or the outer periphery film 211 with an adhesive or the like.

Finally, the winding section 5 is removed from the resulting cylindrical roll, and a first film 213 is attached with an adhesive or the like to one end 6a of the sheet 6 of the roll (the rear surface in FIG. 3) so as to cover the hole 15 that communicates with the inner circumferential surface 12 as well. A second film 214 is attached with an adhesive or the like to the other end 6b of the sheet 6 of the roll (the front surface in FIG. 3) so as to open and cover the hole 16 that communicates with the inner circumferential surface 12. In this way, a filtration cartridge can be manufactured as shown in FIG. 3(f).

The inner film 212 and the outer film 211 may be attached in advance to the opposing short sides of the sheet 6 with adhesive or the like, and then wrapped around the winding section 5. The winding section 5 may also be used in place of the inner film 212. In this case, the portion of the winding section 5 that will become the second water-permeable section 4 may be made of a water-permeable material, or this portion may be made removable.

Another method is to first wind the above-mentioned sheet 6 around the winding section 5 to produce the filter 1, and then form the first film 213, the second film 214, the outer film 211, and the inner film 212.

Specifically, the filter 1 is first prepared by winding the sheet 6 described above around the winding section 5. Next, the part of the inner circumferential surface 12 of the filter 1 that will become the second water-permeable portion 4 and the part of the outer circumferential surface 11 that will become the first water-permeable portion 3 are protected by a member such as a protective sheet. Finally, a water-impermeable material is applied or sprayed onto the inner circumferential surface 12, outer circumferential surface 11, one end surface 13 (upper surface), and other end surface 14 (lower surface) of the filter 1 to form the first film 213, the second film 214, the outer circumferential film 211, and the inner circumferential film 212. The protective sheet may be removed immediately after the first film 213, the second film 214, the outer circumferential film 211, and the inner circumferential film 212 are formed, but it may also be removed immediately before using the filtration cartridge.

In the case of a thread-wound filter, a thread is prepared instead of the sheet 6, and the thread is wound around the inner film 212 wound around the winding section 5.

In addition, while the case where the non-permeable film 21 is used as the non-permeable material member has been described, the member can also be in the form of a container that covers the surface of the filter 1. In this case, the member is mainly composed of a cap 221, a container body 222, and an inner plug 223, as shown in FIG. 4.

The cap 221 covers the surface 13 (upper surface) on one end side of the filter 1, including the holes 15 that communicate with the inner circumferential surface 12. This makes it possible to prevent liquids such as contaminated water from passing through the surface 13 (upper surface) on one end side of the filter 1 and the openings of the holes 15 that communicate with the inner circumferential surface 12 of the filter 1.

The container body 222 covers the surface 14 (lower surface) on the other end side of the filter 1 with a hole 16 that communicates with the inner peripheral surface 12, and covers the outer peripheral surface 11 of the filter 1 so that a first water permeable portion 3 is formed between the container body 222 and the cap 221. This makes it possible to prevent liquids such as contaminated water from passing through the surface 14 (lower surface) on the other end side of the filter 1 and the outer peripheral surface 11 of the filter 1.

The inner plug 223 covers the inner surface 12 of the filter 1 so that a second water permeable section 4 is formed between the inner plug 223 and the container body 222. This makes it possible to prevent liquids such as contaminated water from passing through the inner surface 12 of the filter 1.

The non-permeable material used for the components may be any material that does not allow liquids such as contaminated water to pass through and is not easily deteriorated by the components of the liquid, such as polypropylene or stainless steel. In addition, an adhesive may be used as the non-permeable material, and the adhesive may be applied to the inner circumferential surface 12, outer circumferential surface 11, upper surface 13, and lower surface 14 of the filter 1 where it is not desired that liquids pass through.

Although the cap 221 and the inner plug 223 have been described as separate bodies, it is also possible to form the cap 221 and the inner plug 223 as a single unit, as shown in FIG. 5.

The filtration cartridge thus formed can be used by placing it in a conventional, widely used container for placing filters. This allows contaminated water to flow from the first water permeable section 3 to the second water permeable section 4 of the filtration cartridge, or from the second water permeable section 4 to the first water permeable section 3, to perform purification treatment.

When contaminated water is treated using the filtration cartridge of this embodiment, the smaller the spatial velocity SV (a value indicating how many times the volume of the filter 1 the amount of contaminated water is treated per unit time, which is the value obtained by dividing the flow rate of the contaminated water by the volume of the filter), the higher the purification capacity. On the other hand, if the spatial velocity SV is small, the treatment speed (treatment amount) of the contaminated water will be reduced. Therefore, the spatial velocity SV may be determined taking into consideration the treatment speed and purification capacity, and may be, for example, 20 h ^-1 or less, preferably 2 to 8 h ^-1 . In this way, it becomes possible to appropriately purify the contaminated water using the filtration cartridge.

The first water-permeable section 3 and the second water-permeable section 4 may be openings (holes) having a circular or other shape.

(Modification)
Next, a modified example will be described with reference to Fig. 6 to Fig. 7(b). Fig. 6 shows a filtration cartridge 300 according to the modified example. As shown in Fig. 6, the filtration cartridge 300 has a cylindrical filter 1 similar to that of the above embodiment, an inner plug 323 provided so as to contact the entire inner circumferential surface 12 of the filter 1, and an exterior body 322 provided so as to cover the entire outer circumferential surface 11 of the filter 1.

The inner plug 323 and the exterior body 322 are made of the same non-permeable material as the low water permeability section 2 described in the above embodiment, and are members that prevent liquid from passing through the inner surface 12 and outer surface 11 of the filter 1. According to the filtration cartridge 300 of this modified example, when liquid such as contaminated water is supplied to one side (top or bottom) of the filter 1, the liquid is filtered by passing vertically through the filter 1, and is discharged from the other side (top or bottom) of the filter 1. This makes it possible to ensure a processing time even with the same size as a conventional filter.

Figure 7(a) shows a schematic diagram (cross-sectional view) of a filtration device 400 to which a filtration cartridge 300 can be attached, and Figure 7(b) shows an exploded view (cross-sectional view) of the filtration device 400.

As shown in FIG. 7(b), the filtration device 400 includes a main body 402 and a lid 500. The main body 402 is formed with a space 404 having a space for mounting the filtration cartridge 300, and a flow path 406 communicating with the space 404. The lid 500 is also formed with two flow paths 502, 504.

When using the filtration device 400, as shown in FIG. 7(a), the filtration cartridge 300 is attached to the space 404 of the main body 402 via the cylindrical spacer 602, and the lid 500 is attached to the main body 402. When attaching the lid 500, a cylindrical spacer 604 is provided in the flow path 504 of the lid 500. The diameters of the cylindrical spacers 602 and 604 are smaller than the diameter of the filter 1, so that the spacers 602 and 604 do not stop the flow of contaminated water. In this embodiment, the diameters of the cylindrical spacers 602 and 604 are the same as the diameter of the inner plug 323. In addition, in FIG. 7(a), the height of the spacer 604 is higher than the height of the spacer 602, but they may be the same height. If the heights of the spacers 602 and 604 are the same, the conditions for the contaminated water to flow can be the same on the upper and lower surfaces of the filtration cartridge 300. In addition, by making the cylindrical spacers 602 and 604 the same size, the manufacturing cost of the cylindrical spacers 602 and 604 can be reduced. Note that instead of the cylindrical spacers 602 and 604, the inner plug 323 may be extended in the vertical direction.

According to the filtration device 400 of FIG. 7(a), when liquid such as contaminated water is flowed through the flow path 502, the liquid passes through the flow path 406 and is supplied into the filter 1 from the lower side of the filtration cartridge 300. The liquid that has been treated by passing from bottom to top inside the filter 1 is then discharged from the upper surface of the filter 1 and passes through the flow path 504 to be discharged outside the filtration device 400.

As described above, by allowing an appropriate amount of contaminated water to pass between the upper and lower surfaces of the filter 1 according to the height of the cylindrical spacers 602, 604 as in this modified example, it is possible to ensure the processing time for liquids such as contaminated water, as in the above embodiment.

When the filtration cartridge 300 is attached to the filtration device 400 as shown in Fig. 7(a) and Fig. 7(b), the exterior body 322 does not need to be provided on the outer peripheral surface 11 of the filter 1. In this case, it is preferable to make the outer peripheral surface 11 of the filter 1 and the inner peripheral surface forming the space portion 404 of the main body portion 402 as tightly as possible. Also, instead of the inner plug 323, a non-permeable member such as a film may be provided on the inner peripheral surface 12 of the filter 1.

In the above modified example, the filtering device 400 is a device that supplies liquid such as contaminated water from the bottom side of the filtering cartridge 300 and discharges the treated liquid from the top side, as shown in Figures 7(a) and 7(b), but this is not limited to the above. In other words, the filtering device 400 may be configured to supply liquid such as contaminated water from the top side of the filtering cartridge 300 and discharge the treated liquid from the bottom side.

REFERENCE SIGNS LIST 1 filter 2 low water-permeable section 3 first water-permeable section 4 second water-permeable section 5 roll-up section 6 sheet 11 outer peripheral surface 12 inner peripheral surface 13 surface at one end 14 surface at the other end 15 hole communicating with inner peripheral surface 16 hole communicating with inner peripheral surface 21 non-water-permeable film 22 container 211 outer peripheral film

Claims (7)

A filter containing a functional material;
a low water permeability portion that is provided with a material having a lower water permeability than the filter and allows water to pass between one end side of an outer circumferential surface of the filter and the other end side of an inner circumferential surface of the filter;
A filtration cartridge comprising: the low water permeability portion is a member covering a surface of the filter,
The filtration cartridge according to claim 1, wherein the member has a first water-permeable portion formed on one end side of the outer peripheral surface of the filter and a second water-permeable portion formed on the other end side of the inner peripheral surface of the filter. The member is a water-impermeable film,
3. A filtration cartridge as described in claim 2, comprising: a first film covering one end surface of the filter, including holes communicating with the inner circumferential surface; a second film covering the other end surface of the filter with holes communicating with the inner circumferential surface; an outer peripheral film covering the outer circumferential surface of the filter so that the first water-permeable portion is formed between the outer peripheral film and the first film; and an inner peripheral film covering the inner circumferential surface of the filter so that the second water-permeable portion is formed between the inner peripheral film and the second film. The member is
a cap that covers a surface on one end side of the filter including a hole that communicates with the inner peripheral surface;
a container body that covers the outer peripheral surface of the filter such that the first water permeable portion is formed between the outer peripheral surface and the cap, and that covers the other end side surface of the filter by opening a hole that communicates with the inner peripheral surface;
an inner plug that covers the inner circumferential surface of the filter such that the second water permeable portion is formed between the inner plug and the container body;
3. The filtration cartridge of claim 2, comprising: The filtration cartridge according to claim 4, wherein the cap and the inner plug are integrally formed. The filtration cartridge according to any one of claims 1 to 5, wherein the functional material is at least one of layered double hydroxide, zeolite, and activated carbon. 4. The filtration cartridge according to claim 2, wherein an area of the first water permeable portion is different from an area of the second water permeable portion.

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