JP2021176609A - Water purification cartridge and water purifier - Google Patents

Abstract

To provide a water purification cartridge capable of maintaining its ability to purify heavy metals in a short time for a longer period of time.SOLUTION: A water purification cartridge (1) includes activated carbon, a heavy metal remover for removing heavy metals from raw water, and a hollow fiber membrane (5), and the amount of the heavy metal remover is 25 wt.% or more relative to the amount of the activated carbon.SELECTED DRAWING: Figure 1

Description

The present invention relates to a water purification cartridge and a water purifier.

As a device for filtering tap water, a pitcher-type water purifier that is easy to install and can be used easily has become widespread, and the cartridge used for this pitcher-type water purifier has become the mainstream type that filters only by its own weight. There is.

Reference 1 describes a water purification cartridge and a water purifier including a hollow fiber membrane and activated carbon.

Japanese Unexamined Patent Publication No. 2004-230335 (published on August 19, 2004)

The water purification cartridge is required to stably maintain the ability to purify water in a short time, such as the ability to remove heavy metals, for a long period of time.

One aspect of the present invention has been made to solve such a problem, and an object of the present invention is to provide a water purification cartridge capable of maintaining the ability to purify heavy metals in a short time for a longer period of time.

In order to solve the above problems, the water purification cartridge according to one aspect of the present invention includes activated carbon, a heavy metal removing material for removing heavy metals in raw water, and a hollow fiber membrane, and the amount of the heavy metal removing material is increased. It is 25% by weight or more with respect to the amount of the activated carbon.

According to one aspect of the present invention, it is possible to provide a water purification cartridge and a water purifier capable of maintaining the ability to purify heavy metals in a short time for a longer period of time.

It is sectional drawing which shows an example of the water purification cartridge which concerns on embodiment of this invention. It is a graph which shows the water purification capacity which concerns on Example 1. It is a graph which shows the water purification capacity which concerns on the comparative example 1. It is a graph which shows the water purification capacity which concerns on the comparative example 2. It is a graph which shows the water purification capacity which concerns on the comparative example 3. It is a graph which shows the relationship between the compounding amount of titanium silicate in the water purification cartridge which concerns on the Example of this invention, and the lead removal rate.

Hereinafter, one embodiment of the present invention will be described in detail.

<Water purification cartridge>
The water purification cartridge according to one aspect of the present invention includes activated carbon, a heavy metal removing material for removing heavy metals in raw water, and a hollow fiber membrane, and the amount of the heavy metal removing material is 25 weights with respect to the amount of the activated carbon. % Or more. By blending the heavy metal removing agent having the above particle size and activated carbon in the above amounts, the ability to purify heavy metals in a short time can be maintained for a longer period of time. In the present specification, the adsorbent contained in the cartridge (for example, activated carbon, heavy metal removing material and other adsorbent) is also collectively referred to as "adsorbent".

[Activated carbon]
In one aspect of the invention, the water purification cartridge comprises activated carbon. Activated carbon satisfactorily removes various impurities contained in raw water.

Activated carbon includes vegetable (wood, cellulose, sawdust, charcoal, coconut shell charcoal, raw ash, etc.), coal (peat, carbonized carbon, brown charcoal, bituminous charcoal, anthracite, tar, etc.), petroleum (oil residue, oil residue, etc.) (Sulfuric acid sludge, oil carbon, etc.), pulp waste liquid, synthetic resin, etc. are carbonized, and if necessary, gas activation (steam, carbon dioxide, air, etc.) and chemical activation (calcium chloride, magnesium chloride, zinc chloride, phosphoric acid, sulfuric acid, etc.) , Crucible soda, potassium hydroxide, etc.). Examples of the fibrous activated carbon include those obtained by carbonizing and activating a precursor made from polyacrylonitrile (PAN), cellulose, phenol, and coal-based pits.

In one aspect of the present invention, the form of the activated carbon is not particularly limited, and examples thereof include powdered, granular, fibrous, powdered and / or molded activated carbon obtained by solidifying granular activated carbon with a binder resin. Molded molded activated carbon is preferred. By using the granular molded activated carbon, it is possible to prevent clogging of the hollow fiber membrane or the like by the activated carbon and maintain the ability to purify heavy metals in a short time for a longer period of time.
In one form of the present invention, the form of the activated carbon is preferably granular, and may be, for example, powdered, granular, fibrous, powdered and / or molded activated carbon obtained by solidifying granular activated carbon with a binder resin. By using granular activated carbon, the filtration resistance can be reduced, and a sufficient amount of water flow can be obtained even with the self-weight filtration type.

The particle size of the activated carbon is not particularly limited, but as an example, the particle size of the activated carbon is preferably in the range of 0.250 to 4.00 mm. The particle size of the activated carbon is more preferably 0.425 to 2.00 mm. When the particle size is 0.250 mm or more, the ability to purify heavy metals by activated carbon in a short time can be maintained for a long period of time. Further, when the particle size is 4.00 mm or less, the surface area of the activated carbon is secured, the contact efficiency with the raw water is high, and impurities in the raw water can be efficiently removed.

The particle size of activated carbon is measured by a sieving method using a JIS standard sieve specified in JIS K 1474.
The particle size of the activated carbon may be appropriately selected according to the specific gravity and the particle size of the heavy metal removing material so that the activated carbon and the heavy metal removing material are uniformly mixed and dispersed in the water purification cartridge.

The pore size of the activated carbon is not particularly limited, but is preferably in the range of 0.7 to 5 nm. Further, it is more preferably 0.8 to 2 nm. According to this configuration, impurities in raw water can be efficiently removed.

The pore size of the activated carbon is calculated by obtaining the nitrogen adsorption isotherm by the nitrogen adsorption method and analyzing the nitrogen adsorption isotherm.

In one aspect of the present invention, the activated carbon is preferably contained in an amount of 5 to 70% by weight, more preferably 20 to 60% by weight, based on the total amount of the adsorbent contained in the cartridge. When activated carbon is contained in the adsorbent in the above-mentioned blending amount, impurities in the raw water can be efficiently removed.

Further, as the activated carbon, for example, one in which silver or the like is attached and / or mixed with the activated carbon may be used. According to this configuration, the water purification cartridge can be provided with an antibacterial function.

In one aspect of the present invention, the activated carbon may be used alone or in combination of two or more. For example, activated carbons having different pore diameters may be mixed and used depending on the impurities to be removed. According to this configuration, the water purification cartridge can purify various impurities.

[Heavy metal remover]
In one aspect of the present invention, the water purification cartridge preferably further includes a heavy metal removing material. The heavy metal removing material can remove heavy metals contained in raw water. In one aspect of the present invention, examples of the heavy metal removed by the heavy metal removing material include lead and the like. Above all, according to one aspect of the present invention, lead can be preferably removed. Further, the heavy metal in the raw water can be in various forms, and examples thereof include a soluble heavy metal that dissolves in water, a particulate heavy metal having a diameter of 0.1 μm or less, and the like. Any form can be stably removed for a long period of time according to one aspect of the present invention.

The heavy metal removing material is not particularly limited, and examples thereof include zeolite, a weakly acidic cation exchange resin, and a chelate resin. The heavy metal removing material is preferably zeolite. By using zeolite as the heavy metal removing material, heavy metals in raw water can be suitably removed.

In one aspect of the present invention, the form of the heavy metal removing material is not particularly limited, and for example, a granular molded heavy metal removing material obtained by solidifying a powdery, granular, powdery and / or granular heavy metal removing material with a binder resin or the like. However, a granularly molded heavy metal removing material is preferable. By using the granularly molded heavy metal removing material, clogging of the hollow fiber membrane or the like can be prevented, and the ability to purify heavy metals in a short time can be maintained for a longer period of time.

In one aspect of the present invention, the particle size of the heavy metal removing material is preferably 90% by weight or more of the total weight metal removing material having a particle size of 0.250 to 2.00 mm. When the particle size of the heavy metal removing material is within the above range, heavy metals in raw water can be suitably removed. The particle size of the heavy metal removing material can be measured by the same method as the method for measuring the particle size of activated carbon.

Further, the particle size of the heavy metal removing material may be appropriately selected according to the specific gravity and particle size of the activated carbon so that the activated carbon and the heavy metal removing material are uniformly mixed and dispersed in the water purification cartridge.

In one aspect of the present invention, the blending amount of the heavy metal removing material may be 25% by weight or more, more preferably 30% by weight or more, based on the activated carbon. With such a blending amount of the heavy metal removing material, heavy metals in raw water can be suitably removed. The blending amount of the heavy metal removing material is preferably 60% by weight or less, more preferably 50% by weight or less, based on the activated carbon. When the heavy metal removing material is blended in such an amount, the heavy metal removing material and the activated carbon are uniformly mixed, and the heavy metal in the raw water can be suitably removed.

In one aspect of the present invention, the target raw water is not limited, but in particular, NSF / ANSI standard No. Based on 53, it is preferable to target raw water having a lead concentration of 150 μg / L ± 10% at pH 8.5. It is preferable that the target raw water has lead reduced to 10 μg / L or less, which is the maximum permissible concentration in the treated water, by the water purification treatment of the water purification cartridge. The shape of lead contained in raw water varies depending on the raw water, but NSF / ANSI Standard No. Based on 53, the shape of lead in raw water at pH 8.5 is particulate lead.

[Other adsorbents]
The water purification cartridge according to one aspect of the present invention may contain a material other than activated carbon and a heavy metal removing material as an adsorbent, depending on the mode of use. Other adsorbents include, for example, natural adsorbents (acidic white clay, etc.), synthetic adsorbents (bacterial adsorbent polymer, hydroxyapatite, molecular sieve, silica gel, silica-alumina gel adsorbent, porous glass, Kay). Inorganic adsorbents such as titanium acid (titanium acid); organic adsorbents such as molecular adsorbent resins, ion exchange resins, ion exchange fibers, chelate resins, chelate fibers, highly absorbent resins, highly water-absorbent fibers, oil-absorbing resins, and oil-absorbing agents. Etc., known ones can be mentioned.

In one aspect of the present invention, it is preferable that titanium silicate is contained in an adsorbent in an amount of 10% by weight or more as another adsorbent. It is more preferable that titanium silicate is contained in an amount of 20% by weight or more, and more preferably 25% by weight or more is contained. When titanium silicate is contained in an amount of the above weight% or more, heavy metals in raw water can be suitably removed.

[Hollow fiber membrane]
In one aspect of the present invention, the water purification cartridge includes a hollow fiber membrane as a membrane filter. By using a hollow fiber membrane as the membrane filter, the membrane area per unit volume becomes large and the filtration rate of raw water becomes stable.
NSF / ANSI Standard No. At 53, the raw water having a lead concentration of 150 μg / L ± 10% at pH 8.5 contains particulate lead. Lead cannot be reduced by heavy metal removers alone. Therefore, the inventors of the present application examined the combination of a heavy metal removing agent with some kind of filter, and as a result, came up with the idea of using a hollow fiber membrane. When the water purification cartridge includes a hollow fiber membrane as a membrane filter, lead in raw water can be more preferably removed. Further, since the water purification cartridge includes both the heavy metal removing material and the hollow fiber membrane, it is possible to maintain a stable heavy metal removing ability for a long time.

The hollow fiber membrane is suitably used for filtering and removing granules having a size of 0.1 μm or more containing microorganisms and bacteria. Various porous and tubular hollow yarn films can be used as the hollow yarn membrane, for example, cellulose-based, polyolefin (polyethylene, polypropylene) -based, polyvinyl alcohol-based, ethylene / vinyl alcohol copolymer, polyether-based, poly. Various materials such as methyl methacrylate (PMMA) type, polysulfone type, polyacrylonitrile type, polytetrafluoride ethylene type, polyvinylidene fluoride (PVDF) type, polyvinylidene fluoride type, polyester type, polyamide type, aromatic polyamide type, etc. Can be used. Among them, a polyolefin-based hollow fiber membrane such as polyethylene or polypropylene is preferable in consideration of the handleability and processing characteristics of the hollow fiber membrane.

The outer diameter of the hollow fiber membrane is preferably 20 to 2000 μm, the pore diameter is 0.01 to 1 μm, the porosity is 20 to 90%, and the film thickness of the hollow fiber membrane is 5 to 300 μm. Further, the pore diameter is a value measured by a bubble point measuring method (partially modified for hollow fiber membrane measurement) according to ASTM F316-80 or JIS K3832, and is most preferably 100 kPa or more.

Further, it is desirable that the hollow fiber membrane is a so-called permanently hydrophilic hollow fiber membrane having a hydrophilic group on the surface. Compared with the case where the surface of the hollow fiber membrane is hydrophobic, the filtration water flow at its own weight is faster.

A water purification cartridge in which a hydrophobic hollow fiber membrane and a hydrophilic hollow fiber membrane are mixed in order to prevent air bubbles contained in the supply water from staying on the surface of the hollow fiber membrane, hindering filtration water flow and reducing the filtration flow rate. As a result, air bubbles may be easily removed.

The filling density of the hollow fiber membrane is more preferably 40 to 70%. As a result, the flow rate of raw water in the water purification cartridge can be increased to the extent that it can be used as a pitcher type water purifier, and a relatively large amount of raw water can be purified in a short time.

The filling density of the hollow fiber membrane is S for the cross-sectional area of the fixed portion of the hollow fiber membrane in the direction perpendicular to the fiber axis of the hollow fiber membrane, A for the outer diameter cross-sectional area of one hollow fiber membrane, and A for the hollow fiber membrane. When the number of openings is F, the following formula filling density σ (%) = {(A × F) / S} × 100
Is required from.
The filling density of the hollow fiber membrane is more preferably in the range of 43 to 67%, more preferably in the range of 45 to 65%.

When the hollow fiber membrane knitted fabric described in Utility Model Registration No. 1994065 is loaded as the form of the hollow fiber membrane, the number of hollow fiber membranes used can be easily grasped, so that the packing density can be easily controlled. At the same time, since the hollow fiber membrane knitted fabric can be easily loaded in a sushi roll shape or a fold shape, it is easy to manage the hollow fiber knitted fabric intervals at equal distances, and even if the target packing density is different, the hollow fiber membrane can be easily loaded. And it can be evenly dispersed. Furthermore, even after being processed as a water purification cartridge, by unraveling the warp threads near the ends of one or more hollow fiber membranes used as wefts of the hollow fiber knitted fabric, one or more hollow fiber membranes can be further formed. Dispersed and preferred.

As a result, the effective film area of the hollow fiber membrane to be treated can be positively increased, the space between the hollow fibers can be reduced, and the retention of air can be reduced. Therefore, the processing speed can be remarkably improved and the filtration flow rate can be stabilized.

In one aspect of the present invention, the lower limit of the total membrane area of the hollow fiber membrane ^{is preferably 0.1 m 2} and more preferably 0.12 m ² or more. From the viewpoint of the filtration rate and the life of the water purification capacity, it is more preferably ^{0.15 m 2 or more.}

The upper limit of the total membrane area of the hollow fiber membrane ^{is preferably 0.5 m 2} or less, and ^{more preferably 0.4 m 2} or less. From the viewpoint of miniaturization of the water purification cartridge, it is more preferably ^{0.3 m 2 or less.}

[Structure of water purification cartridge]
The water purification cartridge according to one aspect of the present invention may be a self-weight filtration type water purification cartridge. The structure of the water purification cartridge according to one aspect of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view showing an example of a water purification cartridge according to an aspect of the present invention. As shown in FIG. 1, the case body 3 of the water purification cartridge 1 is formed with a raw water inlet 2 and a purified water outlet 6. The case body 3 is filled with an adsorbent 4 (activated carbon and heavy metal removing material) on the upstream side near the raw water introduction port 2, and a hollow fiber membrane 5 is provided on the downstream side near the purified water outlet 6. .. By arranging the adsorbent 4 and the hollow fiber membrane 5 in this order from the upstream side in this way, there is no concern that the purified water will be contaminated with bacteria or the like after being filtered by the hollow fiber membrane 5, which is preferable. Further, since the water purification cartridge according to one aspect of the present invention can be realized with a simple structure, it can be suitably used for a self-weight filtration type water purification cartridge as in this aspect.

In addition, by filling in this way, air bubbles contained in the raw water and air bubbles staying in the adsorbent layer and between the hollow fiber membranes are minimized, the passing water is prevented from stagnation, and normal filtration water flow is performed. Can be done. As a result, the filtration time can be shortened, and the inherent filtration removal ability can be stably exhibited.

Further, the adsorbent 4 and the hollow fiber membrane 5 may have a partition or may not have a partition. It is preferable that there is no partition from the viewpoint of easy passage of water, easy escape of air inside, and large amount of adsorbent filling due to space saving.

Further, when a heavy metal removing material in which the pH of water affects the lead reduction performance is used, a membrane filter capable of capturing particulate lead may be provided on the upstream side of the water purification cartridge. With this configuration, particulate lead contained in water can be suitably removed regardless of the pH of water.

<Water purifier>
The water purifier according to one aspect of the present invention is a water purifier provided with the water purification cartridge described in <Water Purification Cartridge>. The water purifier can suitably remove heavy metals in raw water.

〔summary〕
The present invention is not limited to this, but includes the following inventions.

(1) A water purification cartridge comprising activated carbon, a heavy metal removing material for removing heavy metals in raw water, and a hollow fiber membrane, wherein the amount of the heavy metal removing material is 25% by weight or more with respect to the amount of the activated carbon.
(2) The water purification cartridge according to (1), wherein 90% by weight of the heavy metal removing material has a particle size of 0.25 to 2.00 mm.

(3) The water purification cartridge according to (1) or (2), wherein the activated carbon has a particle size of 0.250 to 4.00 mm.

(4) The water purification cartridge according to any one of (1) to (3), wherein the total membrane area of the hollow fiber membrane ^{is in the range of 0.1 to 0.3 m 2.}

(5) The water purification cartridge according to any one of (1) to (4), wherein the heavy metal removing material is zeolite.

(6) The water purification cartridge according to any one of (1) to (5), wherein the heavy metal is lead.
(7) The water purification cartridge according to any one of (1) to (6), which is a self-weight filtration type.

(8) A water purifier provided with the water purification cartridge according to any one of (1) to (7).

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

An embodiment of the present invention will be described below.

[Heavy metal processing capacity test of water purification cartridge]
<Example 1>
A polyethylene hollow fiber membrane (hollow fiber membrane manufactured by Mitsubishi Chemical Co., Ltd., product name EX270) is used as the hollow fiber membrane, and a water purification outlet of a cylindrical case body (inner diameter φ40 mm) having an outer diameter of φ44 mm is formed. The hollow fiber membrane was fixed with a urethane resin so that the effective length of the hollow fiber membrane was 35 mm. The layered film area of the hollow fiber was 0.13 m ² .

Next, an adsorbent was filled on the side of the columnar case body in which the raw water introduction port was formed, in which the hollow fiber membrane was fixed at one end, to obtain a water purification cartridge.

Activated carbon and a heavy metal removing material were used as the adsorbent. The activated carbon was granularly molded activated carbon, and the one having a sieve diameter in the range of 0.425 mm to 2.00 mm by the sieving method specified in JIS K 1474 was used.

As the heavy metal removing material, 14.5 g of ATS powder manufactured by BASF, which was granularly molded to 0.250 to 0.60 mm with a polyethylene binder, was used. The weight of the heavy metal removing material was 30% by weight with respect to the total weight of the adsorbent (total amount of activated carbon and heavy metal removing material) and 42.6% by weight with respect to the amount of activated carbon.

After immersing this purified water cartridge in raw water for 15 minutes, the time required to filter 1 L of raw water and the lead concentration in the filtered water were measured.

As a target of filtration, raw water having a lead concentration of 150 ppb in water at pH 8.5 (soluble lead 90 to 120 ppb, particulate lead 30 to 60 ppb having a diameter of 0.1 μm or less) was used.

<Comparative Examples 1 to 3>
The water purification cartridges of Comparative Examples 1 to 3 were prepared. Table 1 shows the amount of activated carbon in the water purification cartridges of Comparative Examples 1 to 3, the size and amount of the heavy metal removing material, the compounding ratio, the form of the membrane filter, and the membrane area.

The structure of each water purification cartridge will be described. Comparative Example 1 has a structure in which a pleated molding filter is provided in the cartridge, and the activated carbon and the heavy metal removing material are also molded in the same filter.

Comparative Example 2 has a structure in which activated carbon and a heavy metal removing material are filled, and a pleated membrane filter is provided downstream of the water purification cartridge.

Comparative Example 3 has the same structure as the water purification cartridge described in Example 1, but differs from Example 1 in that the amount of the heavy metal removing material is smaller than that of the water purification cartridge of Example 1, as shown in Table 1. ..

The results of the heavy metal processing capacity test of the water purification cartridges of Example 1 and Comparative Examples 1 to 3 shown in Table 1 are shown in FIGS. 2 to 5. FIGS. 2 to 5 show the integrated flow rate, the time required for filtering 1 L of raw water at the time when the integrated flow rate is passed, and the lead concentration in the filtered water in the water purification cartridges of Examples 1 and Comparative Examples 1 to 3. It is a figure which shows the relationship with.

As shown in FIG. 2, in Example 1, even if the integrated flow rate of water flow exceeds 110 gallons, the lead concentration in the filtered water is less than 10 ppb, and the ability of the water purification cartridge to process lead is almost the same from the start of the test. It didn't change. In addition, the time required to filter 1 L of raw water was stable and short from the start of the test even when the integrated flow rate exceeded 110 gallons (less than 1200 seconds).

As shown in FIG. 3, in Comparative Example 1, the lead concentration in the filtered water was less than 10 ppb even if the integrated flow rate of water flow increased, but with respect to the filtration time, when the integrated flow rate became 60 gallons or more, the raw water. The time to filter 1 L increased sharply.

As shown in FIG. 4, in Comparative Example 2, the lead concentration in the filtered water was less than 10 ppb even when the integrated flow rate of water flow increased, but with respect to the filtration time, 1 L of raw water was used even at the start of the test. It took a long time of 1500 seconds or more to filter.

As shown in FIG. 5, in Comparative Example 3, the lead concentration in the filtered water exceeded 50 ppb from the beginning of the test.

From the above, it was clarified that the water purification cartridge of Example 1 maintained the ability to process lead in a short time even if the integrated flow rate increased, as compared with the water purification cartridges of Comparative Examples 1 to 3.

[Reference example]
In addition to the activated carbon and heavy metal removing material, the amount of titanium silicate contained as an adsorbent and the lead removing rate were tested. Raw water having a lead concentration of 150 μg / L at pH 8.5 was used as a filtration target. FIG. 6 is a graph in which the lead concentration in the filtered water at the time of start-up is plotted for each amount of titanium silicate.

As shown in FIG. 6, when titanium silicate is contained in an adsorbent in an amount of 20% by weight or more, the lead removal rate exceeds 94% and titanium silicate is contained in an adsorbent in an amount of 30% by weight or more. In that case, the lead removal rate was 96%. NSF / ANSI Standard No. In 53, since the lead removal rate is required to be 95% or more, the water purification cartridge exhibits a water purification ability that clears the NSF / ANSI standard by containing 25% by weight or more of titanium silicate in the adsorbent. It became clear.

The present invention can be used for water purification.

1 Water purification cartridge 2 Raw water inlet 3 Case body 4 Adsorbent 5 Hollow fiber membrane 6 Purified water outlet

Claims (8)

It is provided with activated carbon, a heavy metal removing material for removing heavy metals in raw water, and a hollow fiber membrane.
A water purification cartridge in which the amount of the heavy metal removing material is 25% by weight or more with respect to the amount of the activated carbon. The water purification cartridge according to claim 1, wherein 90% by weight of the heavy metal removing material has a particle size of 0.25 to 2.00 mm. The water purification cartridge according to claim 1 or 2, wherein the activated carbon has a particle size of 0.250 to 4.00 mm. The water purification cartridge according to any one of claims 1 to 3, wherein the total membrane area of the hollow fiber membrane ^{is in the range of 0.1 to 0.3 m 2.} The water purification cartridge according to any one of claims 1 to 4, wherein the heavy metal removing material is zeolite. The water purification cartridge according to any one of claims 1 to 5, wherein the heavy metal is lead. The water purification cartridge according to any one of claims 1 to 6, which is a self-weight filtration type. A water purifier including the water purification cartridge according to any one of claims 1 to 7.

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