JPH059117Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrochemical sterilization device suitably used in water purifiers for home use, commercial use, etc.

[Problems to be solved by conventional techniques and ideas] In recent years, various water purifiers using activated carbon have been used to remove chlorine odor from tap water. However, since this water purifier decomposes and removes chlorine that is administered for the purpose of sterilization, bacteria such as E. coli are adsorbed to the activated carbon of the water purifier, multiply without being sterilized, and leak into drinking water. There is a problem with putting it away.

In view of the above points, water purifiers are equipped with hollow fiber membranes that filter bacteria such as E. coli on the downstream side of activated carbon.
A water purifier has been proposed in which activated carbon is impregnated with sterilizing silver. However, in the former water purifier, since E. coli and other bacteria are filtered through a hollow fiber membrane, the total amount of E. coli basically does not decrease, and in the latter water purifier, there are problems such as silver leaching into drinking water. .

On the other hand, a method has been proposed to electrochemically sterilize adsorbed E. coli by applying voltage to granular activated carbon (T. Matsunaga, et al.,
Appl. Microbiol. 54, 1330-1333 (1988)).

FIG. 7 is a schematic diagram showing a conventional electrochemical sterilizer, and the sterilizer for treating tap water supplied from a supply pipe 31 includes a case 32 having an inlet 32a and an outlet 32b, and a case 32 having an inlet 32a and an outlet 32b. Granular activated carbon layer 33 filled on the outlet 32b side of 32
A pair of electrodes 34a and 34b are respectively disposed on the upstream side of the activated carbon layer 33 and the case 32, that is, on the inlet 32a side, and a power source 35 is connected to the electrodes 34a and 34b. Note that the activated carbon layer 33 has conductivity and therefore acts as an electrode.

According to this electrochemical sterilizer, by applying a voltage to the pair of electrodes 34a and 34b, bacteria such as E. coli adsorbed on the activated carbon layer 33 are sterilized by electrochemical action, and purified water flows out of the system. be able to. However, since the activated carbon layer 33 is composed of granular activated carbon, the contact ratio of the granular activated carbon is very small, making it difficult to uniformly apply voltage to the entire activated carbon layer 33. In particular, the electrode 34a disposed in the aqueous phase and the granular activated carbon tend to come into contact with each other, making it impossible to form a uniform electric field and significantly reducing the sterilization efficiency.

The purpose of this invention is to provide an electrochemical sterilization device that can form a uniform electric field while maintaining electrodes in a non-contact state, can efficiently adsorb and remove odor components, and can efficiently sterilize microorganisms such as bacteria. It's about doing.

[Means and effects for solving the problem] The present invention is a sterilizer in which at least one pair of electrodes to which a voltage is applied are arranged in a non-contact state, and in which at least one of the pair of electrodes is arranged in a non-contact state. An electrochemical device in which the electrode is formed of a water-permeable adsorbent containing activated carbon fibers and having a papermaking structure, and a flow path for a processing liquid that has passed through the water-permeable adsorbent is formed between the pair of electrodes. With a sterilizer,
This solves the above problem.

According to the electrochemical sterilizer having the above configuration, at least one of the pair of electrodes is formed of a water-permeable adsorbent containing activated carbon fiber and having a papermaking structure. Since the water-permeable adsorbent has a paper structure, the activated carbon fibers are bound to each other, and the structure is dense and has a high density and mechanical strength. Furthermore, since the water-permeable adsorbent has high mechanical strength, the contact ratio between the activated carbon fibers does not change due to the supply of the liquid to be treated, and density unevenness does not occur. In addition, since the contact ratio between activated carbon fibers is significantly greater than that of granular activated carbon simply housed in a container, a voltage can be uniformly applied and a uniform electric field can be formed between the electrodes. In addition, activated carbon fibers have extremely high adsorption capacity, and the water-permeable adsorbent has a dense structure. It can efficiently adsorb bacteria and microorganisms. Therefore, odor components and the like can be adsorbed and removed, and bacteria adsorbed to the adsorbent can be sterilized by applying voltage to the pair of electrodes arranged in a non-contact manner.
By applying a voltage to the pair of electrodes, microorganisms in the liquid to be treated can be sterilized even during the process of flowing through the flow path, so the sterilizing effect can be enhanced.

[Example] The present invention will be described in more detail below based on the accompanying drawings.

FIG. 1 is a schematic cross-sectional perspective view showing the present invention.
This device has a pair of hollow cylindrical electrodes 1a and 1b constituting an inner cylinder and an outer cylinder, and the pair of hollow cylindrical electrodes 1a and 1b are arranged concentrically apart from each other in a non-contact state. It is set up. In order to adsorb odor components such as chlorine and bacteria in tap water,
The pair of electrodes 1a and 1b are formed of a water-permeable molded adsorbent having a paper-like structure and containing activated carbon fibers.

Further, the pair of electrodes 1a and 1b are connected to a DC or AC power source 2 via carbon fiber or metal lead wires. Note that the hollow cylindrical electrodes 1a, 1
Since the electrodes 1a and 1b are made of a molded adsorbent having a papermaking structure containing activated carbon fibers, the electrodes 1a and 1b can be easily connected to the power source 2 by embedding or inserting lead wires.

In addition, in order to maintain the pair of electrodes 1a, 1b in an electrically insulated state, the opening at one end of the electrodes 1a, 1b has a size equal to or smaller than the hollow part of the hollow cylindrical electrode 1a constituting the inner cylinder. It is sealed with a perforated sealing member 3 having an opening of the same size, and the other end opening is completely closed with a sealing member 4. The perforated sealing member 3 and the sealing member 4 are made of an electrically insulating material such as silicone rubber, and can be fixed to the end surfaces of the hollow cylindrical electrodes 1a and 1b using an adhesive or the like, if necessary.

According to the above-mentioned sterilizer, since the electrodes 1a and 1b are formed of a water-permeable adsorbent having a paper-like structure containing activated carbon fibers having a larger specific surface area than granular activated carbon, the contact ratio of the activated carbon fibers is large. Can ensure conductivity. In addition, in the process of passing from the outside of the electrode 1b that makes up the outer tube through the flow paths between the electrodes 1a and 1b and into the hollow part of the electrode 1a that makes up the inner tube, chlorine, etc. contained in treated water such as tap water, etc. It can efficiently adsorb odor components and microorganisms such as E. coli.
Furthermore, since the electrodes 1a and 1b are disposed in a non-contact manner, electrical insulation can be ensured. Therefore, by applying voltage to each electrode 1a, 1b from the power source 2, a uniform electric field can be formed between the electrodes 1a, 1b, and the adsorbed microorganisms can be efficiently sterilized. Further, according to the above-mentioned sterilizer, not only the adsorption by the activated carbon fibers but also the electrostatic attraction force caused by the application of voltage can attract heavy metal ions and the like contained in the treated water to the electrodes 1a and 1b and remove them.

In addition, when processing with the sterilizer shown in FIG. 1, a pipe connected to a suction pump or the like may be attached to the opening of the perforated seal member 3, and tap water etc. may be sucked and processed. Preferably, the structure is as shown in FIGS. 2 and 3. FIG. 2 is a schematic sectional view showing another embodiment of the present invention, and FIG.
FIG. 3 is a flow diagram showing processing steps using the apparatus shown in the figure.

In this example, the sterilizer shown in FIG. A space 6 is formed.

In a sterilizer with such a structure, the above case 5
By attaching the inlet 5a to a water faucet or the like, tap water or the like is passed from outside the electrode 1b, through the flow path between the electrodes, and into the hollow part of the electrode 1a, and is then connected to the outlet 5b of the case 5. In the process of flowing out, odor components can be efficiently adsorbed and removed, and by applying voltage to each electrode 1a, 1b from the power source 2, microorganisms adsorbed to the electrodes 1a, 1b can be removed in a state where a uniform electric field is formed. Can be sterilized efficiently.

Furthermore, by installing the sterilizer shown in FIG. 2 in a treatment line as shown in FIG. 3, a large amount of commercial water, etc. can be treated efficiently. In the treatment line shown in FIG. 3, water from a water storage tank 7 is supplied by a pump 8 to an inlet 5a of a case 5 of the sterilizer. In the same manner as described above, odor components and the like are adsorbed and removed from the supplied water in the process of passing through the electrodes 1b and 1a, and the water is efficiently sterilized by applying voltage to each electrode 1a and 1b from the power source 2. Ru. The water from which odor components and the like have been removed and which has been sterilized is stored in a storage tank 9.

The above pair of electrodes formed of a water-permeable adsorbent may be made of a water-permeable material such as a porous film, sheet, cloth, or metal strainer, and a water-permeable member such as a porous film, sheet, cloth, or metal strainer. However, in order to improve the integrity, the activated carbon fibers may be composed of a heat-melting synthetic resin, pleated hemp or pulp, and a paper strength agent. It is preferable that the adsorbent is formed of a molded adsorbent having a bonded and held paper-making structure.

The above-mentioned activated carbon fiber is not particularly limited,
Various materials such as fibrous activated carbon obtained by activating carbon fibers can be used. Examples of carbon fibers include polymer fibers such as polyacrylonitrile, phenolic resins, and cellulose resins, and pitch fibers such as petroleum pitch fibers and coal pitch fibers. At least one type of activated carbon fiber is used.

The specific surface area of activated carbon fiber is 8 to 20 Å in pore radius.
It is preferable that the area is usually 500 to 2500 m ² /g.
If the specific surface area is less than 500 m ² /g, the adsorption capacity will not be sufficient, and if it exceeds 2500 m ² /g, it is generally uneconomical. In addition, as activated carbon fiber, the fiber diameter is usually 2~
A material with a fiber length of about 30 μm and a fiber length of about 0.1 to 10 mm can be used.

As a heat-melting synthetic resin, the softening point is 50 to 200℃.
It is preferable to use synthetic resins such as polyethylene, polypropylene, polyvinyl alcohol, polyacrylonitrile, etc. as such synthetic resins. Among these thermoplastic resins, polyacrylonitrile is particularly preferred. The heat-melting synthetic resin may be in the form of powder, particles, etc., but is preferably fibrous in order to prevent the pores of the activated carbon fibers from being blocked. The heat-melting synthetic resin fibers that can be used have a fiber diameter of about 5 to 100 μm and a fiber length of about 0.5 to 10 mm. Note that the heat-melting synthetic resin fiber may be a composite fiber whose surface is coated with the above-mentioned synthetic resin, which does not undergo heat fusion or deterioration during production of the molded adsorbent.

The ratio of activated carbon fiber and thermofusible synthetic resin is
Usually activated carbon fiber/thermal melt synthetic resin = 100/5
~40 parts by weight, preferably about 100/10~40 parts by weight. If the proportion of the heat-melting synthetic resin is less than 5 parts by weight, the strength of the molded adsorbent will be reduced, and if it exceeds 40 parts by weight, the pores of the activated carbon fibers will be blocked and the adsorption capacity will be reduced.

Further, instead of the heat-melting synthetic resin, pleated hemp or pulp and a paper strength enhancer may be used. When using the above materials, activated carbon fiber accounts for 50 to 95% of the total weight of the shaped adsorbent, chips of at least one of hemp or pulp treated to have pleats on the surface account for 2 to 6% by weight, and the paper strength The enhancer may be used in an amount of 1 to 3% by weight based on the hemp or pulp.

Note that, in order to increase the strength of the molded adsorbent formed from activated carbon fibers and thermofusible synthetic resin, it is preferable to contain non-thermofusible fibers as a reinforcing material.

Non-thermofusible fibers are not particularly limited as long as they do not melt or change in quality at the temperature during production of the molded adsorbent, but include, for example, pulp; natural fibers such as cotton and linen; aromatic polyamide fibers and aromatic polyesters. Synthetic fibers such as fibers, high melting point polyethylene fibers, high melting point polypropylene fibers, high melting point polyacrylonitrile fibers; semi-synthetic fibers such as rayon; and inorganic fibers such as glass fibers, carbon fibers, alumina fibers, and metal fibers. Ru. One or more types of fibers can be used. Such non-thermofusible fibers have a fiber diameter of 2 to 10 μm and a fiber length of 0.5 to 10 mm.
Can be used to a certain extent.

The preferred ratio of activated carbon fiber to non-thermal fusible fiber is usually activated carbon fiber/non-thermal fusible fiber = 100/
It is about 5 to 80 parts by weight. If the proportion of non-thermofusible fibers is less than the above range, the reinforcing properties will be reduced, and if it exceeds the above range, the content of activated carbon fiber will be relatively reduced and the adsorption capacity will be reduced.

Note that the shaped adsorbent may contain additives such as a dispersant, a stabilizer, a viscosity modifier, and a filler within a range that does not adversely affect the adsorption capacity and strength.

The shaped adsorbent can be manufactured by preparing an aqueous slurry containing activated carbon fibers, heat-melting synthetic resin, etc., and then suction molding the slurry using a suction mold.

Note that in preparing the slurry, it is preferable to beat the slurry. Furthermore, in order to increase the yield by suction molding, a surfactant having an agglomerating effect, particularly a polymer flocculant or a yield improver, may be added. The solid content concentration in the slurry is usually about 0.1 to 2% by weight.

When the molded adsorbent has a hollow cylindrical shape, suction molding is performed by connecting a suction pump to a hollow cylindrical suction mold with many holes formed on the circumference, and sucking from the inside of the mold. This can be done by depositing activated carbon fibers or the like on the surface of a suction mold. In addition, a hollow cylindrical shaped adsorbent can be obtained by heating and drying the wet shaped adsorbent after suction molding and bonding the activated carbon fiber with a heat-melting synthetic resin or the like. Heat drying can be performed at a temperature of about 100 to 200°C.

According to suction molding, molded adsorbents of various shapes can be obtained by changing the shape of the suction mold. Further, during suction molding, by adjusting the suction force, suction time, etc., the density, thickness, and water permeability of the molded adsorbent can be easily controlled. Furthermore, since the adsorbent is suction molded, the molded adsorbent has excellent uniformity.

The thickness of the electrode formed of the shaped adsorbent having the above-mentioned papermaking structure is usually 0.5 to 50 mm, preferably 1 to 50 mm.
It is about 25mm. If the thickness is less than 0.5 mm, the mechanical strength will decrease, and if it exceeds 50 mm, it is generally uneconomical.

Further, at least one of the pair of electrodes may be formed of a water-permeable adsorbent having a papermaking structure containing activated carbon fibers. For example, as shown in FIG. 4, a water-impermeable solid cylindrical electrode 11a is used as the inner cylinder, and a hollow cylinder formed of a water-permeable molded adsorbent containing activated carbon fibers as described above is used as the outer cylinder. The electrodes 11a and 11b may be arranged concentrically in a non-contact state using the shaped electrode 11b. In this example, one open end is connected to a perforated sealing member so that a flow path for treated water is formed between the outer circumferential surface of the solid cylindrical electrode 11a and the inner circumferential surface of the hollow cylindrical electrode 11b.
3, and the other open end is completely closed with a sealing member 14. Note that the solid cylindrical electrode 11a is not limited to the papermaking structure forming adsorbent containing the activated carbon fibers, but may be formed of a conductive material such as graphite, metal, etc.

When using a sterilizer as shown in Figure 4,
Odor components and microorganisms contained in tap water etc. can be adsorbed during the process of passing through the hollow cylindrical electrode 11b, and by applying voltage to the electrodes 11a and 11b, the adsorbed microorganisms can be sterilized.

Note that the sterilizer may include a plurality of pairs of hollow cylindrical electrodes arranged concentrically. In this case, a large amount of odor components, microorganisms, etc. can be adsorbed and removed using the plurality of pairs of electrodes, and a large amount of microorganisms can be sterilized. Further, the electrode is not limited to a cylindrical shape, but may have a hollow polygonal cross section, a flat plate shape, or the like. For example, as shown in FIG.
1b, 21c, and 21d may be connected to the power source 22 and mounted in a non-contact manner in a case 25 having an inlet 25a and an outlet 25b.

Note that the device shown in FIG. 5 is not limited to a plurality of pairs of electrodes, but may include at least one pair of electrodes. In this case as well, the same effect as described above occurs.

The distance between the electrodes and the applied voltage can be set depending on the desired sterilization properties, processing speed, etc., but usually the distance between the electrodes is about 1 to 20 mm, preferably about 5 to 15 mm, and the applied voltage is about 0.5 to 10 V. is sufficient.

Note that the connection state between the positive electrode and the negative electrode of the power source and each electrode is not particularly limited, and may be connected in a state opposite to that shown in the drawing.

[Effects of the invention] As described above, according to the electrochemical sterilization device of the invention, at least one pair of electrodes to which a voltage is applied are arranged in a non-contact state, so that a uniform electric field can be formed. can. Furthermore, since at least one of the pair of electrodes is made of a water-permeable adsorbent containing activated carbon fibers and having a paper-making structure, chlorine contained in tap water, etc., is absorbed during the process of passing through the water-permeable adsorbent. It can adsorb odor components such as and microorganisms. Therefore, odor components and the like can be adsorbed and removed, and sterilization can be efficiently performed by applying voltage to the electrodes. Moreover, since microorganisms in the liquid to be treated can be sterilized even in the process of flowing through the channel between the electrodes, the sterilizing effect can be enhanced.

[Experimental Examples] The present invention will be described in more detail below based on experimental examples.

Pitch type fibrous activated carbon (manufactured by Ador Co., Ltd., trade name A-15, specific surface area 1500 m ² /g) 70% by weight, Pitch type general-purpose carbon fiber (manufactured by Donac Co., Ltd.) 25% by weight, and thermofusible synthetic A homogeneous aqueous slurry having a solid content of 1% by weight and consisting of 5% by weight of acrylonitrile fibers as resin fibers was prepared. In addition, when preparing the aqueous slurry, the fiber length of each
It was beaten until it became 5 mm.

Next, using a cylindrical mold with a large number of small suction holes on the circumference, the aqueous slurry was deposited on the circumference of the mold while suction was applied from inside the mold, and the wet state formed was The hollow cylindrical body was removed from the mold and dried by heating at 140°C for 2 hours. The obtained molded adsorbent with a papermaking structure has an inner diameter of 28 mm and an outer diameter of 38 mm.
mm, and the length was 10 mm.

Also, in the same way as above, the inner diameter is 10 mm, the outer diameter is 20 mm,
A molded adsorbent having a paper structure with a length of 10 mm was obtained.

Small-diameter molded adsorbents are concentrically accommodated in the obtained large-diameter molded adsorbent, and a perforated sealant made of silicone rubber is attached to one open end using epoxy adhesive, as shown in Figure 1. and a sealing material was adhered to the other open end in the same manner as above to close it.

Next, a lead wire made of carbon cloth (manufactured by Toho Rayon Co., Ltd., high elastic Bestophite HM-40) was attached to the large-diameter molded adsorbent and the small-diameter molded adsorbent.
and connected it to a 0.8V DC power supply.

Further, as shown in FIG. 2, the above-mentioned sterilizer was installed in a case having an inlet and an outlet, and the flow was configured as shown in FIG. 3.

Then, sample water with an E. coli concentration of 60 cells/ml was supplied to the sterilizer at a flow rate of 1 ml/min using a pump.

The bactericidal effect is obtained by collecting a predetermined amount of runoff water at predetermined intervals, dropping it onto an agar medium kept at a temperature of 50℃, solidifying it into a flat plate, and culturing it in an incubator at a temperature of 37℃ for 3 days. After that, evaluation was performed by determining the number of viable bacteria and sterilization efficiency from the number of colonies.

Comparative Example Sample water was treated in the same manner as in the experimental example without applying voltage to the sterilizer, and the sterilization effect was evaluated.

The results are shown in Figure 6. As is clear from FIG. 6, in the comparative example, after the sample water was supplied for 50 hours, the amount of E. coli in the effluent water had significantly increased to 55,200 CFU/ml. In contrast, in the experimental example, even after 50 hours, 3408 CFU/
ml, and it was found that the number of E. coli bacteria decreased significantly.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional perspective view showing the present invention, FIG. 2 is a schematic sectional view showing another embodiment of the present invention, and FIG. 3 is a flow diagram showing the processing steps using the apparatus shown in FIG. 2. Fig. 4 is a schematic cross-sectional perspective view showing still another embodiment of the present invention, Fig. 5 is a schematic cross-sectional view showing another embodiment of the present invention, and Fig. 6 is a graph showing the results of experimental examples and comparative examples. , FIG. 7 is a schematic diagram showing a conventional electrochemical sterilization device. 1a, 1b, 11a, 11b, 21a, 21
b, 21c, 21d...electrodes.

Claims (1)

[Scope of utility model registration request] A sterilizer in which at least one pair of electrodes to which a voltage is applied are disposed in a non-contact state, wherein at least one of the pair of electrodes contains activated carbon fiber and has a papermaking structure and is water permeable. An electrochemical sterilization device characterized in that it is made of an adsorbent and that a flow path for a treatment liquid that has passed through the water-permeable adsorbent is formed between a pair of electrodes.