JP3790346B2 - Water treatment equipment - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a water treatment apparatus for purifying various treated waters such as rivers containing microorganisms, industrial water, and tap water by electrochemical sterilization. In particular, it is suitably used for household water purifiers, water treatment for waterworks, water treatment devices used in factories such as cosmetics, pharmaceuticals and foods.
[0002]
[Prior art]
There are many microorganisms in sea water and fresh water, but some of these microorganisms are pathogenic or adhere to the surface of underwater structures and cause various problems. Therefore, various water treatment apparatuses and treatment methods for sterilizing and sterilizing the microorganisms have been proposed. As a device for sterilizing microorganisms in water, a water treatment device using activated carbon, activated carbon fiber, or the like is known. As a method for sterilizing microorganisms in water, a method of adding hypochlorite, chlorine, ozone or the like to the water to be treated is known.
[0003]
[Problems to be solved by the invention]
However, the water treatment apparatus using activated carbon has the following problems.
1. The granular activated carbon flows into the pipe, the microorganisms adsorbed on the discharged activated carbon grow and adhere to the pipe, and the propagated microorganism re-suspends in water, thereby generating a new pollution source.
2. Microorganisms adsorbed on the activated carbon and activated carbon fibers grow with the passage of time, and the propagated microorganisms resuspend in the water, thereby newly causing contamination. Moreover, the method of adding hypochlorite or chlorine, ozone, etc. to the method of adding to treated water has the following problems.
1. Hypochlorite and chlorine have a strong irritating odor and irritation to the skin, and it has been pointed out that infants with low resistance may experience skin irritation and eye pain, and cannot be used in large quantities. .
2. Hypochlorite and chlorine are consumed by reacting with organic substances in water. For example, when used for purification of tap water, the chlorine concentration at the end decreases as the distance of the water supply pipe increases, and microorganisms Insufficient sterilization.
3. Hypochlorite and chlorine react with organic substances present in water to produce carcinogenic trihalomethanes.
4). Ozone has the problem that ozone itself induces carcinogenicity.
5. Some species cannot be sterilized by hypochlorite, chlorine, or ozone. For example, it has been confirmed that Cryptosporidium, which is a pathogenic worm with mass infection, is not sterilized with chlorine.
6). Depending on the state of the microorganism, sterilization may be difficult due to hypochlorite, chlorine, or ozone. For example, microorganisms attached to structures in water grow to form a microbial film, and this microbial film is known to be highly resistant to chlorine. Because of the low permeability of chlorine, it is difficult to completely sterilize microorganisms present in the microbial coating.
From the above problems, there is a demand for a new sterilization apparatus that is safe for a long period of time and can completely sterilize a problem organism in water without becoming a new source of contamination.
[0004]
The present invention has been made in view of these problems, and relates to an apparatus for electrochemically sterilizing microorganisms present in water by electrochemical biological control, and includes an intake port and a discharge port of water to be treated. A working electrode made of a material selected from metal nitride, metal boride, and metal silicide, and a counter electrode made of a material that does not dissolve even when a direct current is applied, The gist of the water treatment apparatus is that the working electrode and the counter electrode are connected by a DC power source capable of polarity conversion.
[0005]
[Action]
The working electrode of the water treatment apparatus according to the present invention is made of a material selected from metal nitride, metal boride, and metal silicide . Therefore, the working electrode has a low electric resistance, a high corrosion resistance, and is very stable and free from deterioration without being dissolved or oxidized by applying a potential. Therefore, the water treatment apparatus according to the present invention can sterilize microorganisms existing in water in a short time and can be used for a long time. The working electrode can be sterilized for a long period of time by connecting a DC power source capable of polarity conversion and converting the polarity of the working electrode to remove the sterilized microorganisms attached to the working electrode. Moreover, since the to-be-processed water does not electrolyze, the applied electric potential does not change the pH of the treated water.
[0006]
【Example】
Embodiments of the present invention will be described in detail with reference to the drawings. In addition, the water treatment apparatus shown in drawing is an example of invention, and this invention is not limited by this. FIG. 1 is a schematic diagram illustrating the first embodiment. Reference numeral 1a is a container. A plate-like working electrode 2a and a counter electrode 3a are installed in the container 1a. Moreover, 4a shows a water intake and 5a shows a discharge port. The plate-like working electrode 2a and the counter electrode 3a are connected to a DC power source 7a whose polarity can be converted by a lead 6a.
[0007]
The container 1a is formed of an electrically insulating material that can fix the working electrode 2a and the counter electrode 3a, and does not dissolve or corrode even when water is passed through the water inlet 4a. Yes. Further, the shape is not particularly limited. Specific materials include acrylonitrile-butadiene-styrene copolymer, acrylylnitrile-styrene copolymer, polyethylene, polystyrene, polycarbonate, acrylic resin, polyethylene terephthalate, polypropylene, polyvinyl chloride, and other thermoplastic resins, silicon Examples thereof include elastomer resins such as resin, nitrile butylene rubber, chloroprene rubber, urethane elastomer, and polyethylene elastomer. Moreover, metal materials, such as aluminum and its alloy, iron and its alloy, copper and its alloy, and stainless steel, can also be used. However, in this case, it is necessary to coat these metal materials with a material having high electrical insulation.
[0008]
The plate-like working electrode 2a installed in the container 1a is made of a conductive material such as metal nitride, metal boride, or metal silicide . Examples of the metal nitride include titanium nitride, zirconia nitride, vanadium nitride, tantalum nitride, niobium nitride, and chromium nitride. Examples of the metal boride include titanium boride, zirconium boride, half boride, and vanadium boride. , Niobium boride, tantalum boride, chromium boride, molybdenum boride, tungsten boride, etc., and metal silicides include titanium silicide, zirconium silicide, niobium silicide, tantalum silicide, vanadium silicide, Examples thereof include tungsten silicide. Note that the materials described here are a part of them, and depending on the formation method, they may contain two or more kinds of metals, part of oxides, or a mixture of two or more of these compounds. May be.
[0009]
The counter electrode 3a installed in the container 1a is arranged so as not to contact the working electrode 2a. As the counter electrode 3a, a plate-like or mesh-like one can be used without limitation. The counter electrode 3a is made of a material that does not melt even when a direct current is applied, and the material is made of the same material as the working electrode 2a. In addition, platinum, palladium, gold, rhodium, ruthenium, iridium, and these For example, a valve metal mesh such as titanium or tantalum coated with an oxide of carbon, a woven fabric of carbon fiber, a sintered body of a carbon material such as carbon black, graphite, or activated carbon is used.
[0010]
In order to pass a direct current between the plate-like working electrode 2a and the counter electrode 3a, a direct-current power source 7a whose polarity can be changed is used. However, in the case where electric power cannot be supplied by a power line, a manganese battery, an alkaline battery, etc. Primary batteries, secondary batteries such as batteries, nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lead-acid batteries are used. In this case, it is necessary to install a device capable of changing the polarity.
[0011]
In this embodiment, the water to be treated flows in the direction from the intake port to the discharge port as indicated by the arrow in FIG. 1 and contacts the working electrode. At this time, the microorganisms present in the treated water are also affected by the working electrode. Sterilized in contact with. Hereinafter, the action in electrochemical control in which microorganisms are brought into contact with the working electrode and sterilized will be described. When water to be treated containing microorganisms is passed through a water treatment apparatus and a positive potential is applied to the working electrode, the microorganisms in the water can be adsorbed to the working electrode. The positive potential applied to the working electrode has an action of electrochemically sterilizing microorganisms that have contacted the working electrode. That is, microorganisms are adsorbed on the working electrode surface by a positive potential and sterilized on the working electrode surface. The applied positive potential is +0 to 3.0 Vvs. SCE, preferably +0.5 to +2 Vvs. SCE, and the applied potential is 0 V vs. Below SCE, microorganisms cannot be adsorbed on the working electrode and sterilized.
[0012]
Subsequently, when a negative potential is applied to the working electrode, microorganisms and scales adsorbed on the working electrode surface can be desorbed. The applied potential is −0 to −1.5 V vs. SCE, preferably −0.1 to 1.0 V vs. SCE. When the applied potential is −0 Vvs. SCE or more, the microorganisms cannot be detached from the surface of the working electrode, and when it is lower than −1.0 Vvs. SCE, the pH increases. The time for applying the negative potential varies depending on the type and amount of microorganisms adsorbed on the surface of the working electrode, but may be 30 seconds to 60 minutes, preferably 1 minute to 30 minutes. When the time is shorter than 30 seconds, the sterilized microorganisms are not sufficiently detached, and when a positive potential is applied next, other microorganisms adhere to the sterilized microorganisms.
[0013]
FIG. 2 is a schematic diagram illustrating the second embodiment. Reference numeral 1b is a container. A filter-like working electrode 2b and a counter electrode 3b are installed in the container 1b. Reference numeral 4b denotes a water intake port, and 5b denotes a discharge port. The filter-like working electrode 2b and the counter electrode 3 are connected to a DC power source 7b by a lead wire 6b. Further, in order to accurately control the applied potential of the working electrode, the verification electrode 8 is connected to the DC power source 7b by the lead wire 6b. The DC power source 7b is a three-pole power source, and a potentiostat is used. The function generator 9 is connected to the DC power source 7b by a lead wire 6c in order to change the polarity.
[0014]
Example 2 uses a filter-like electrode as the working electrode, and uses the 0 ring 10 made of an insulating resin between the working electrode 2b and the counter electrode 3b, so that the working electrode 2b and the counter electrode 3b are alternately arranged. Except for using the collation electrode 8 and the function generator 9 to prevent contact when installed, it is substantially the same as the first embodiment. That is, for example, the container 2 can be fixed with an electrode, is not dissolved or corroded by water, and is formed of an electrically insulating material, and its shape is not particularly limited.
[0015]
The filter-like working electrode 2b is made of a conductive material such as a metal nitride, a metal boride, or a metal silicide in the same manner as the plate-like working electrode, and further has an adsorbent activated carbon or activated carbon fiber. Etc. may be included. The filter-like working electrode 2b only needs to have pores through which water can be passed, and the thickness thereof is appropriately set according to the water quality of the target water. Further, as the filter-like working electrode 2b, the conductive material is formed on a sintered body in which one or more kinds of particles of the conductive material are mixed, or on a mesh of a valve metal material such as titanium, tantalum, niobium or zirconia. Or a container formed of a mesh of a valve metal material and filled with one or more kinds of particles of the conductive material may be used.
[0016]
The effect of sterilization on microorganisms of the water treatment apparatus according to Example 2 is almost the same as that of Example 1. However, Example 2 uses a filter as a working electrode, and therefore, microorganisms in water compared to Example 1. Contact with the working electrode increases, and as a result, the bactericidal effect increases. Moreover, in Example 2, since a part of microorganisms are captured by the filter-like working electrode, the sterilization effect is higher than that in Example 1. Since the filter-like working electrode 2b and the counter electrode 3b are alternately installed, a direct current is applied to both surfaces of each working electrode 2b. Therefore, microorganisms captured on the working electrode 2b efficiently. Can be sterilized. In addition, when many combinations of a working electrode and a counter electrode are laminated | stacked, the quantity of the water processed in a fixed time can be increased, maintaining a bactericidal effect.
[0017]
【The invention's effect】
Since the water treatment according to the present invention has the above-described configuration, the microorganisms in the water can be sterilized for a long time, and the applied water does not electrolyze the water to be treated, so there is no change in the pH of the treated water. .
[Brief description of the drawings]
1 is a schematic diagram of Example 1. FIG.
2 is a schematic diagram of Example 2. FIG.
[Explanation of symbols]
1a, 1b Container 2a, 2b Working electrode 3a, 3b Counter electrode 4a, 4b Intake port 5a, 5b Drain port 7a, 7b DC power supply

Claims (4)

In a container having an intake port and a discharge port for water to be treated, a working electrode made of a material selected from metal nitride, metal boride, and metal silicide, and a material that does not dissolve even when a direct current is applied. The water treatment apparatus is characterized in that the counter electrode is disposed, and the working electrode and the counter electrode are connected by a DC power source capable of polarity conversion.  The water treatment apparatus according to claim 1, wherein the working electrode and the counter electrode are alternately arranged from the intake port of the water to be treated toward the discharge port so that the working electrode and the counter electrode do not contact each other.  The water treatment apparatus according to claim 1 or 2, wherein the working electrode is a filter.  The water treatment apparatus according to any one of claims 1 to 3, wherein the direct current power source can be applied to a potential at which an applicable potential does not electrolyze the water to be treated.

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