JP2001025772A - Silver elution module as well as silver elution cartridge and purification system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to stably elute specified silver ions for a long period by using hydrophilic porous hollow fiber membranes support and fixed by potting materials in the state of opening hollow parts as partition walls, filling one space with a hardly soluble silver compound and making the other space water permeable. SOLUTION: The silver elution module is a hollow fiber membrane module consisting of the hydrophilic porous hollow fiber membranes 2 supported and fixed in the state of opening the hollow parts by the potting materials 1. The powder silver sulfide is packed into the hollow parts of the hydrophilic porous hollow fiber membranes 2. The hollow fiber membrane parts in the hollow fiber membrane module are immersed and shaken in water containing an acid or oxidizing agent to dilute silver in the water. As a result, the silver ions of a desired concentration density are stably eluted relatively for a long period and more particularly the specific silver ions are eluted in spite of the time contacting with water, by which an antimicrobial property may be effectively imparted to the water. Also, the antimicrobial property may be imparted to the water in a water tank and the propagation of saprophytic bacteria may be prevented even if the water is stored in the water tank for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver elution module for eluting silver in water containing an acid or an oxidizing agent to impart a bactericidal action, a silver elution cartridge using the module, and a water purification system.

[0002]

2. Description of the Related Art Tap water usually contains a trace amount of organic matter, and bacteria are easily propagated by using this as a nutrient source. For this reason, giving antibacterial properties to tap water is an important technical problem.

[0003] One of the methods for imparting antibacterial properties is to add hypochlorous acid to tap water. This is required by the Water Law.

On the other hand, elution of silver is also effective as a means for suppressing the growth of bacteria. It has been well known since ancient times that water stored in silver or copper containers does not rot (germs do not multiply) even when stored for a long time. As a technique utilizing the bactericidal action of such silver, silver-impregnated activated carbon in which a silver compound or metallic silver is impregnated on the surface of activated carbon is known, and as a specific example, for example, granular activated carbon manufactured by Kuraray Chemical Co., Ltd. The TS series can be given. Also, JP-A-10-314754 discloses that
A configuration is disclosed in which activated carbon impregnated with silver chloride or the like and a membrane filter having a relatively large pore size (0.5 to 1 μm) are used in combination. As a result, bacteria having a size exceeding 1 μm are removed by a membrane filter, and bacteria having a size of 1 μm or less are inactivated by the eluted silver ions. It is said that it can supply purified water.

[0005]

However, the technology for adding hypochlorous acid to tap water has the following problems.

In recent years, water purifiers using activated carbon have been widely used for the purpose of removing chlorine odor, musty odor, and the like. However, when this type of water purifier is used, residual chlorine is removed by the activated carbon and the bactericidal property is reduced. Disappeared, and there was a risk of bacteria growing in the water purifier. Recently, a large-scale water purifier (Point of Entrance (PO) installed in a main water supply pipe supplied to the home and purifying all the tap water supplied to the home.
E) Water purifiers are also being used, but such PO
The E water purifier has a similar problem.

[0007] In addition, a water tub of an apartment house, a bath tub at home, etc.
Tap water may need to be pumped for a long time, but in this case, hypochlorous acid may be lost due to decomposition, volatilization, etc., and the antibacterial effect may be lost.

On the other hand, in the technique using silver-impregnated activated carbon, the elution of silver depends on the solubility of the silver compound or metallic silver impregnated on the activated carbon. There was a problem that it was easy to change. In particular, the elution amount greatly fluctuated depending on the contact time with water, and it was difficult to control the elution amount. Furthermore, since various substances are adsorbed on the activated carbon surface, the contact area between silver and water decreases when water is repeatedly purified over a long period of time, and the amount of silver eluted may decrease. In addition, when silver-impregnated activated carbon is used in a water purifier, sterilization is provided by the constant elution of silver near the silver-impregnated activated carbon,
It is difficult to impart bactericidal properties to the water in the flow path after the silver-impregnated activated carbon, and improvements have been demanded from this point as well.

[0009] The water purifier disclosed in Japanese Patent Application Laid-Open No. 10-314754 also has the problem of the silver-impregnated activated carbon described above.
And regarding the stability of silver elution amount during long-term use,
There was room for improvement.

The present invention has been made in view of the above circumstances, and a silver eluting module that stably elutes certain silver ions over a long period of time and imparts bactericidal properties to water regardless of the contact time with water or the like. It is an object to provide a silver elution cartridge and a water purification system.

[0011]

According to the present invention, there is provided a silver eluting module for eluting silver into water containing an acid or an oxidizing agent, the hydrophilic module being supported and fixed with a hollow portion opened by a potting material. It is composed of a porous hollow fiber membrane,
A silver elution module is provided, wherein the hydrophilic porous hollow fiber membrane is used as a partition, one of the spaces is filled with a sparingly soluble silver compound, and the other is made permeable to water.

The silver eluting module of the present invention utilizes a sparingly soluble silver compound as a means for imparting antibacterial properties. The poorly soluble silver compound is not eluted into water only by contact with water, but silver is eluted by causing a chemical reaction when contacted with water containing an acid or an oxidizing agent. Since silver is eluted by such a mechanism, a desired concentration of silver ions can be eluted with good controllability as compared with the conventional technique using silver-impregnated activated carbon depending on the solubility of a silver compound, and in particular, water with water Constant silver ions can be eluted regardless of the contact time.
In addition, since the silver is eluted by the reaction of the sparingly soluble silver compound and the acid or the oxidizing agent, the elution speed is extremely fast as compared with the usual elution in the prior art, and the elution speed can be rapidly increased to a concentration exhibiting antibacterial properties. it can. When the acid or oxidizing agent is consumed by the reaction and disappears, no more silver is eluted. Therefore, it is possible to prevent unnecessary elution of silver by adjusting the concentration of the acid or oxidizing agent. Further, since the aqueous porous hollow fiber membrane is used as a partition wall, one space is filled with the hardly soluble silver compound and the other space is made permeable to water, so that the contact area between the water and the hardly soluble silver compound increases, Silver is eluted efficiently.

Further, according to the present invention, there is provided a silver elution cartridge comprising the above-mentioned silver elution module and a float member.

Further, according to the present invention, there is provided a silver eluting cartridge comprising the above-mentioned silver eluting module and means for attaching to the inner wall surface of the water tank.

When a float member such as a floating bag is attached to the silver eluting module, the silver eluting module can float in water, so that silver is eluted into water more easily without piping work and the antibacterial property. Can be provided. The same advantage can be obtained when a member such as a suction cup, a hook, a ring, or a chain is provided so that the silver elution module can be suspended in the water tank.

The water tank in the above invention is a container for storing and using water, and its form is not particularly limited. Examples thereof include a bath tub, a water receiving tub of an apartment house, a washing tub of a washing machine, and the like.

It is effective to apply the silver elution cartridge of the present invention to, for example, a bathtub. The temperature of the water filled in the bathtub is increased, and the bathtub water is agitated by bathing. Therefore, the concentration of hypochlorous acid is reduced, and bacteria are liable to propagate using organic matter emitted from the human body as a nutrient source. On the other hand, if the silver elution cartridge of the present invention is used, silver can be eluted into bath water to prevent the growth of bacteria. As a method of installing the silver elution cartridge in the bathtub, the water supply or hot water supply pipe to the bathtub is provided, floating in the bathtub water,
A method of hanging from a bathtub wall surface or the like can be used.

It is also effective to apply the silver elution cartridge of the present invention to a water receiving tank of an apartment house or the like. In the receiving tanks of apartment houses, new water is supplied into the receiving tank as the resident uses the water, but at that time, the water stays in the receiving tank for a long time, which is called dead water. There is a possibility that bacteria grow in that part, and bacteria grow in that part even when the management condition of the receiving tank is poor. Therefore, it is effective to prevent the generation of bacteria in the water receiving tank by using the silver elution cartridge according to the present invention.

It is also effective to apply the silver elution cartridge of the present invention to a washing tub of a washing machine. in this case,
Injecting the silver elution cartridge according to the present invention at the rinsing stage, and eluting silver into the rinsing water, for example, to prevent the rotten odor of water contained in the laundry generated at the time when the laundry is hard to dry such as during the rainy season. Can be. In addition, the laundry that has been rinsed in this way is provided with antibacterial properties, and is effective in terms of hygiene.

Further, according to the present invention, there is provided a water purification system characterized in that the silver elution module is provided in a pipe for supplying tap water to a household.

According to this water purification system, the growth of bacteria in the pipe after the removal of residual chlorine can be effectively prevented by eluting silver into the water and imparting sterilization to the water.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The hardly soluble silver compound in the present invention means a silver compound which is hardly soluble in water, and preferred examples thereof include silver sulfide. For example, silver sulfide has a solubility in water of 6.15 × 10 ⁻¹³ g / L (25 ° C.) and is almost insoluble in water. Therefore, silver sulfide is not eluted into water only by contact with water, but is eluted only by contact with water containing an acid or an oxidizing agent. On the other hand, silver chloride has a high solubility in water (1.93 × 10 ⁻³ g / L).
(25 ° C.)), when staying in water for a long time, it tends to be dissolved at a high concentration regardless of the presence or absence of an oxidizing agent such as hypochlorous acid. From the above, it is preferable to use silver sulfide as the hardly soluble silver compound.

In the present invention, when treating water containing no acid or oxidizing agent, it is effective to provide an adding means for appropriately adding an acid or oxidizing agent to the water before contacting the hardly soluble silver compound. It is. This makes it possible to elute silver. As the adding means, for example, a method of charging an acid or an oxidizing agent into a water storage tank, a method of injecting into a water pipe with a pump or the like can be appropriately selected.

The acid or oxidizing agent in the present invention includes
For example, nitric acid, hydrochloric acid, sulfuric acid, hypochlorous acid, aqueous hydrogen peroxide and the like can be mentioned, but in view of danger, reactivity and the like, it is preferable to use hypochlorous acid. When silver is eluted into tap water to which hypochlorous acid has been previously added for sterilization, it is not necessary to add an acid or an oxidizing agent again. In this case, hypochlorous acid is decomposed along with elution of silver, so that the odor and skin irritation of hypochlorous acid can be reduced or eliminated.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a view showing one embodiment of the silver elution module of the present invention. A hollow fiber membrane module comprising a hydrophilic porous hollow fiber membrane 2 supported and fixed in a state where a hollow part is opened by a potting material 1, and powdery silver sulfide is provided in the hollow part of the hydrophilic porous hollow fiber membrane. It is filled (not shown). The filling method of the powdered silver sulfide into the hollow portion, for example,
A method can be employed in which powdery silver sulfide is sprayed on the end face of the hollow fiber membrane module and charged by vibrating. By immersing and shaking the hollow fiber membrane portion of the hollow fiber membrane module in water containing an acid or an oxidizing agent, silver can be eluted into the water.

FIG. 2 is a view showing another embodiment of the silver elution module of the present invention. A hollow fiber membrane module comprising a hydrophilic porous hollow fiber membrane 2 supported and fixed in a state where a hollow part is opened by a potting material 1. Powdered silver sulfide is provided in the hollow part of the hydrophilic porous hollow fiber membrane. It is filled (not shown). The hollow fiber membrane part of the hollow fiber membrane module has a water inlet 3
And a container 5 having an outlet 4 for water. Water containing acid or oxidizing agent is introduced through water inlet 3;
It comes into contact with the surface of the hollow fiber membrane filled with powdered silver sulfide and penetrates into the hollow portion of the hollow fiber membrane, where silver is eluted by the reaction of the acid or oxidizing agent and the powdered silver sulfide, and is led out from the water outlet 4.

FIG. 3 is a view showing another embodiment of the silver elution module of the present invention. This is a hollow fiber membrane module in which a hydrophilic porous hollow fiber membrane 2 supported and fixed in a state where both ends are opened with a potting material 1 at both ends in a container 5 is provided. Is filled with powdered silver sulfide (not shown), and a water inlet 3 and a water outlet 4 are provided at both ends of the hollow fiber membrane module. Water containing an acid or an oxidizing agent is introduced from the water inlet 3 and comes into contact with the surface of the hollow fiber membrane filled with the powdered silver sulfide and penetrates into the hollow portion of the hollow fiber membrane, where the reaction between the acid or the oxidizing agent and the powdered silver sulfide occurs. To elute silver, and the silver is extracted from the outlet 4 of water.

FIG. 4 is a schematic diagram showing an example of a silver elution cartridge according to the present invention, and FIG. 5 is a schematic diagram showing another example of a silver elution cartridge according to the present invention. FIG. 6 is a diagram showing an example in which the silver elution cartridge shown in FIG. 4 is used in a bathtub.

In FIGS. 4 and 5, the hollow fiber membrane 2 is supported and fixed by the potting portion 1 while keeping the hollow portion open. The hollow portion of the hollow fiber membrane 2 is filled with silver sulfide powder (not shown).

The silver eluting cartridge shown in FIG. 4 has a structure in which a float member 20 made of an air bag is disposed in the potting section 1. The silver elution cartridge shown in FIG. 5 has a configuration in which the potting section 1 and the suction cup 22 are connected by a chain 21. As described above, by floating or suspending the hollow fiber membrane portion in water, water penetrates into the hollow fiber membrane and silver is eluted by a reaction between silver sulfide and an acid or oxidizing agent such as hypochlorous acid, Antibacterial properties can be imparted to the water in the water tank.

FIG. 6 is a view showing an example in which the silver elution cartridge shown in FIG. 4 is used in a bathtub. The silver elution cartridge 8 shown in FIG.
Is floating. By doing so, silver can be quickly eluted into the bath water, and bacterial growth can be prevented.

FIG. 7 is a diagram showing a flow of the water purification system according to the present invention. A water purifying cartridge 1 containing a silver elution module 13 and activated carbon shown in FIG. 3 is connected to a branch pipe 12 that branches from a water supply pipe 11 and supplies tap water to each household.
4 is attached. Downstream of the water purification cartridge 14, a pipe 16 for supplying tap water to each of the water taps 15, 15 ', 15 "is provided. A water tap to the kitchen (for example, the water tap 15 in the figure) is provided. Hollow fiber membrane cartridge 1
7 is attached.

By arranging the silver elution module in the pipe for supplying the tap water to the home in this way, it is possible to impart sterility to the tap water, and the bacteria remaining in the water retained in the pipe at home. Can be prevented from breeding.

The water purification system of the present invention may further include a water purification cartridge having a function of removing residual chlorine. As a specific example of the water purification cartridge having the function of removing residual chlorine, a water purification cartridge including a filter medium capable of decomposing and removing residual chlorine such as activated carbon and calcium sulfite can be given. When activated carbon is used, trihalomethane such as chloroform contained in water can be removed in addition to residual chlorine, and preferably, when calcium sulfite is used, it is effective for hot water and large-scale treatment, They can be used separately or in combination as appropriate.

The water purification system of the present invention may further include a cartridge having a turbidity removing function. As a specific example of the cartridge having the turbidity removing function,
An example is a hollow fiber membrane module including a porous hollow fiber membrane supported and fixed with a hollow portion opened by a potting material. For example, if a hollow fiber membrane module composed of a porous hollow fiber membrane is disposed at a tap water supply port (water tap) of a kitchen or the like used for eating and drinking, turbidity such as iron rust contained in tap water is reduced. It can be effectively removed. In addition, when a hollow fiber membrane is used, the volume efficiency of the membrane area is improved as compared with the flat membrane, and the filtration life can be extended, which is preferable.

As a preferred embodiment of the water purification system of the present invention, a water purification cartridge filled with activated carbon is disposed downstream of the silver elution module, and a porous hollow fiber membrane is provided in a tap water supply tap serving as a tap water supply port. Can be cited. Here, it is desirable that the water purification cartridge filled with the activated carbon is disposed upstream of a branch point where the water purification cartridge branches toward each household. In this way, it is possible to purify all the water supplied to the household, and to use safe water from which residual chlorine and volatile organic substances have been removed in places other than drinking and use such as kitchens, for example, in washrooms and baths. Can be enabled.

[0038]

The present invention will be described in more detail with reference to the following examples.

<Example 1> The membrane portion of the silver elution module shown in FIG. 1 was immersed and shaken in 100 ml of conditioned water having a hypochlorous acid concentration adjusted to 1.0 ppm, and after 5, 10 and 30 minutes. Was measured by ICP emission spectroscopy. Table 1 shows the results.

<Example 2> From the water inlet of the silver elution module shown in FIG. 2, 0.5, 1.0, and 2.0 liters of adjusted water whose hypochlorous acid concentration was adjusted to 1.0 ppm was supplied. m
The water was passed in, and the silver concentration in the treated water derived from the outlet of the water was measured by ICP emission spectroscopy. Table 2 shows the results.

Example 3 From the water inlet of the silver elution module shown in FIG. 3, 0.5, 1.0, and 2.0 liters of conditioned water whose hypochlorous acid concentration was adjusted to 1.0 ppm was supplied. m
The water was passed in, and the silver concentration in the treated water derived from the outlet of the water was measured by ICP emission spectroscopy. Table 2 shows the results.

<Comparative Example 1> The membrane portion of the silver elution module shown in FIG. 1 was immersed and shaken in 100 ml of water containing no hypochlorous acid, and contained in treated water after 5, 10 and 30 minutes. Silver concentration was measured by ICP emission spectroscopy. Table 1 shows the results.

Comparative Example 2 Water containing no hypochlorous acid was added to water from the water inlet of the silver elution module shown in FIG.
Water was passed at 5, 1.0, and 2.0 liters / min, and the concentration of silver contained in the treated water derived from the outlet of the water was measured by ICP emission spectroscopy. Table 2 shows the results.

<Comparative Example 3> Water containing no hypochlorous acid was added to water from the water inlet of the silver elution module shown in FIG.
Water was passed at 5, 1.0, and 2.0 liters / min, and the concentration of silver contained in the treated water derived from the outlet of the water was measured by ICP emission spectroscopy. Table 2 shows the results.

[0045]

[Table 1]

[0046]

[Table 2]

As is clear from the results shown in Tables 1 and 2, in Examples 1 to 3, silver could be eluted stably regardless of the immersion time and the flow rate of water. On the other hand, Comparative Example 1
In the conditioned water containing no hypochlorous acid concentration of ~ 3, the amount of silver eluted was 6 ppb, which is the detection limit of the ICP emission spectrometer.
It was below. In addition, when water was passed up to an integrated flow rate of 1000 liters under the condition of a water flow rate of 2.0 liter / min in Examples 2 and 3, treated water was sampled at every integrated flow rate of 100 liters, and the silver concentration was measured. The variation was small, and it was confirmed that silver in the range of 20 to 30 ppb was stably eluted in both Examples 2 and 3.

[0048]

As described above, the silver eluting module, the silver eluting cartridge, and the water purification system of the present invention are:
Since a sparingly soluble silver compound is used as an antibacterial property imparting means, a desired concentration of silver ions can be stably eluted for a relatively long time, and particularly, a constant silver ion can be eluted regardless of the contact time with water. To effectively impart antibacterial properties.

Further, the use of the silver elution cartridge of the present invention makes it possible to easily impart antibacterial properties to the water in the water tank, and to prevent the propagation of various bacteria even if the water is stored in the water tank for a long time. it can.

Further, by using the water purification system of the present invention, it is possible to prevent the growth of bacteria in the piping after removing residual chlorine. In addition, by purifying all water supplied to the home, safe water from which residual chlorine and volatile organic substances have been removed can be used in places other than drinking use, such as kitchens, for example, toilets, baths, and the like. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a silver elution module of the present invention.

FIG. 2 is a diagram showing an example of a silver elution module of the present invention.

FIG. 3 is a diagram showing an example of a silver elution module of the present invention.

FIG. 4 is a view showing an example of a silver elution cartridge of the present invention.

FIG. 5 is a view showing an example of a silver elution cartridge of the present invention.

FIG. 6 is a view showing a usage example of the silver elution cartridge of the present invention.

FIG. 7 is a diagram showing an example of the water purification system of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane 2 Potting material 3 Water inlet 4 Water outlet 5 Container 6 Bath tub 7 Bath water 8 Silver elution cartridge 11 Water supply pipe 12 Branch pipe 13 Silver elution module 14 Water purification cartridge 15, 15 ', 15 "Water tap 16 Pipe 17 Hollow fiber membrane cartridge 20 Float member 21 Chain 22 Sucker

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/50 560 C02F 1/50 560B 560E B01D 63/02 B01D 63/02 C02F 1/28 C02F 1/28 G 1/44 1/44 H 1/76 1/76 Z F term (reference) 4D006 GA14 HA01 JA03Z JA07Z KA03 KA33 KA72 KB12 KD06 KD24 MB09 NA01 PB02 PB06 PB07 PB24 PC51 PC52 4D024 AA01 AA02 AA06 AB11 BA05 BA11 CA04 DB11 DB23 DB30 4D050 AA01 AA04 AA08 AA10 AB06 BA05 BA06 BB06 BB07 BB08 BB09 BC10 BD02 BD03 BD04 BD06 CA06 CA09

Claims (12)

[Claims] 1. A silver elution module for eluting silver into water containing an acid or an oxidizing agent, comprising a hydrophilic porous hollow fiber membrane supported and fixed with a hollow portion opened by a potting material. A silver elution module, wherein a hydrophilic porous hollow fiber membrane is used as a partition, one space is filled with a sparingly soluble silver compound, and the other space is made permeable to water. 2. The silver eluting module according to claim 1, wherein the hardly soluble silver compound is silver sulfide. 3. The silver eluting module according to claim 1, wherein the acid or the oxidizing agent is hypochlorous acid. 4. A silver elution cartridge comprising the silver elution module according to claim 1 and a float member. 5. A silver eluting cartridge comprising the silver eluting module according to claim 1, and means for attaching the silver eluting module to an inner wall surface of a water tank. 6. A water purification system, wherein the silver elution module according to any one of claims 1 to 3 is provided in a pipe for supplying tap water to a household. 7. The water purification system according to claim 6, further comprising a water purification cartridge having a function of removing residual chlorine. 8. The water purification system according to claim 7, wherein the water purification cartridge contains at least activated carbon. 9. The water purification system according to claim 7, wherein the water purification cartridge contains at least calcium sulfite. 10. The water purification system according to claim 6, further comprising a cartridge having a turbidity removing function. 11. The water purification system according to claim 10, wherein the cartridge having the turbidity removing function is a cartridge having at least a porous hollow fiber membrane. 12. A water purification cartridge filled with activated carbon is disposed downstream of the silver elution module, and a cartridge made of a porous hollow fiber membrane is disposed at a tap water tap. Item 12. A water purification system according to any one of Items 6 to 11.