JP2006247466A - Method for preventing adhesion and/or controlling removal of aquatic insect - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical control method which prevents adhesion of aquatic insects living in river water or the like for a long period, and their larvae and nests with no water pollution concerns, and/or an electrochemical control method which removes the adhering aquatic insects, their larvae and nests only during a necessary period with considering the growth of the aquatic insects in river water. <P>SOLUTION: In the electrochemical control method, two or more electrically conductive base materials are installed in at least a part of a water passage, and disposed so as to work as electrodes, and a power source applying current between the electrodes is installed, which damages at least a part of the cells of aquatic organisms with bacteriostatic action and hydrolysis reaction on the surfaces of the conductive base materials, or decomposes/denatures organic substances contacting the conductive base material to enable adhesion prevention and/or removal. This method hardly influences water quality, and can obtain inhibition effect over a long period of time. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides two or more conductive substrates and a power source for energizing them as a method for preventing adhesion and / or removal when attached to aquatic insects that live in river water or the like, or their larvae, or their nests. The present invention relates to a method for preventing and / or controlling the adhesion of chickenpox insects by energizing them.

  Tobikera are well known as aquatic insects that inhabit river water. Tobikeras are also living organisms that are regarded as indicators of good water quality. However, in a river water guideway used for hydropower generation, etc., it may adhere to the inner wall surface of the waterway and cause a problem as a power generation pest as a cause of a decrease in the amount of water. For this reason, a great deal of effort has been expended to clean the wall surface and to wash away the attached aquatic insects.

In order to solve the above problems and prevent and / or remove chickenpox insects, attempts have been made in the past to use a smooth surface using a resin or metal material, or to use a material exhibiting a super-water-repellent function at the interface. Has been made. However, a method that has been exposed to nature for a long time, functions stably, and does not adversely affect water quality from the viewpoint of environmental protection has not yet been developed.
For example, antifouling methods against contamination by living organisms attached to the surface of underwater structures that are in contact with seawater or fresh water include adding bactericidal substances to the surface to be protected, and paints containing organotin compounds In general, an antifouling method has been used in which a coating film is formed and an organic tin compound is eluted or chlorine generated by electrolyzing seawater is used. However, these methods generate harmful substances, and there are concerns about the impact on the organisms due to water pollution.
In recent years, methods have been proposed for controlling organisms attached to the surface of an underwater structure, seawater, or fresh water that is electrochemically contacted without generating harmful substances. In this electrochemical biological control method, when a potential higher than a predetermined potential at which a direct electrochemical reaction with a microorganism is confirmed is applied to the microorganism, coenzyme A, one of the redox substances inside the microorganism, is irreversible. It is oxidized and induces a decrease in the respiratory activity of the microorganism and the permeation barrier of the microorganism membrane, thereby killing the microorganism (Japanese Patent Publication No. 6-91821: see Patent Document 1). Japanese Patent Application Laid-Open No. 9-248554 (see Patent Document 2) includes a step of adsorbing and sterilizing microorganisms in water on the surface of the conductive substrate by applying a positive potential to the conductive substrate in water. By applying a higher positive potential to the conductive substrate, the cells of microorganisms adsorbed on the surface of the conductive substrate are destroyed, and the sterilized microorganisms adhering to the conductive substrate and their decomposition products are detached. The invention is summarized as a method for controlling an aquatic microorganism characterized in that Further, in Japanese Patent No. 3105024 (see Patent Document 3), in water, a positive potential is applied to the conductive substrate to adsorb and sterilize the microorganisms in the water on the surface of the conductive substrate (+0 to 1). .5 V vs SCE) and a step (−0 to −0.4 V vs SCE) for removing sterilized microorganisms adsorbed on the surface of the conductive substrate by applying a negative potential to the conductive substrate. An invention having a gist of a method for controlling an underwater microorganism characterized by the above is described. Japanese Patent Laid-Open No. 2001-198572 (see Patent Document 4) adsorbs microorganisms in water to the surface of the conductive substrate by applying a positive potential that does not cause electrolysis to the conductive substrate in water. Sterilizing, applying a negative potential that causes electrolysis to the conductive substrate, reducing the surface of the conductive substrate, inducing an alkaline substance to the surface of the conductive substrate, and adsorbing to the surface of the conductive substrate And a process for removing the decomposed microorganisms and degradation products thereof, an invention having a gist of a method for controlling underwater microorganisms is described.

However, both methods prevent the adhesion of microorganisms formed at the initial stage of adhesion, and in particular, under conditions where the amount of microorganisms is small compared to seawater, such as river water, varicella insects, their larvae and their nests. In many cases, the adhesion formation is caused by physical contact, and it is assumed that the effect cannot be expected sufficiently.
Japanese Patent Publication No. 6-91821 (page 3, line 42 to line 46, page 8, line 42 to line 44) JP-A-9-248554 (page 6, line 4 to line 8) Japanese Patent No. 3105024 (page 3, line 20 to line 27, Fig. 1-4) JP 2001-198572 A (page 3, line 5 to line 8)

  The present invention relates to aquatic insects that live in river water, etc. for a long period of time without concern about water pollution, an electrochemical control method for preventing the attachment of larvae and nests, and / or growth of chickenpox insects in river water. In view of this, an electrochemical control method for removing aquatic insects, larvae and nests attached only when necessary is an issue.

The present invention provides the conductive group by providing two or more conductive substrates on at least a part of the water path and arranging them so as to function as electrodes, and by energizing the conductive substrates. A first aspect of the adhesion prevention and / or removal control method of aquatic insects, or larvae thereof, or their nests, which is prevented and / or removed from the wood, is the adhesion prevention control method. The method for preventing adhesion and / or removal of aquatic insects according to the first aspect, characterized in that an energization amount between the conductive substrates is +50 mA / m ² or more, In the removal control method, the amount of energization between the conductive base materials is +400 to +1000 mA / m ² . Summary of Then, by energizing between the conductive substrates, at least a part of cells of aquatic organisms is damaged with a water splitting reaction, or an organic substance in contact with the conductive substrate is decomposed / denatured. The adhesion prevention and / or removal control method for aquatic insects according to any one of the first to third aspects, characterized in that the adhesion prevention and / or removal is characterized in that The fifth aspect is the adhesion prevention and / or removal control method for aquatic insects according to any one of the first to fourth aspects, in which the current supplied to is controlled to be reversed between positive and negative.

  The method for controlling the prevention and / or removal of aquatic insects according to the present invention is such that at least a part of the water path is provided with two or more conductive substrates, and the conductive substrates function as electrodes. In addition, by providing a power source for energization between the electrodes, at least a part of the cells of aquatic organisms is damaged due to sterilization or water decomposition reaction of microorganisms on the surface of the conductive substrate, or the conductive substrate It is possible to prevent and / or remove adhesion by decomposing / denaturing organic substances in contact with water, and it is a control method that has almost no effect on water quality, and it can be stably controlled over the long term. An effect is obtained. Moreover, in the installed positive electrode and negative electrode, the influence on the water quality can be mitigated by controlling the release of salt at a necessary time by the reversal operation. Furthermore, the adhesion prevention and / or removal function in the existing equipment can be improved, and the cleaning and cleaning work in the water path can be reduced. In addition, in hydroelectric power conduits that take river water, the roughness coefficient increases due to attached inorganic and organic matter, aquatic organisms, their larvae and nests, and the amount of water cannot be secured, leading to a decrease in power generation. However, according to the control method of the present invention, the deposits are eliminated, which can contribute to high efficiency stabilization of the power generation efficiency.

The place where the conductive base material is installed is not particularly limited as long as it is placed in part or all of the water channel of the water system inhabited by aquatic insects so as to be in contact with water. Furthermore, since the method of the present invention efficiently uses the electrochemical reaction and its configuration, it is recommended that the reaction rate be set in a place where the flow rate of water including the varicella insect and its larvae is stable to some extent. This is preferable in improving uniformity and comprehensively controlling desired adhesion prevention and removal.
As the conductive base material, various shapes suitable for applications can be used. There are various types such as a plate shape and a column shape, a honeycomb type having pores, a mesh type, and a plate-shaped perforated plate (for example, punching metal, expanded metal, lath plate, etc.). In some cases, there are composite shapes. The pore shape of the conductive substrate is not particularly limited, such as a mesh or a lattice. The size of the mesh, lattice or perforation is preferably 1 mm to 10 mm in the vertical dimension and 1 mm to 10 mm in the horizontal dimension.
A microbial film (biofilm or slime) is formed on the conductive base material using the accumulated foreign matter as a nutrient source. Therefore, by providing a conductive base material having conductivity on at least a part of two or more sheets, arranging the conductive base material as an electrode, and providing a power source for energizing between the electrodes, It is possible to obtain an effect of long-term suppressing adhesion of chickenpox insects, their larvae and nests existing in the vicinity of the electrode accompanying microbial control and water decomposition reaction on the substrate surface. In addition, the installed positive and negative electrodes adsorb inorganic salts present in water, but the effect of not affecting the water quality is also expected by controlling the re-release of the inorganic components adhering to the electrode by the reversal operation. it can.

The conductive substrate used in the present invention is made of a metal, an oxide thereof, a resin, an inorganic material, or the like, and is not particularly limited. In that case, a conductive material such as a metal or its oxide may be used, or a non-conductive material such as a resin is used as a base to form a film on the surface by plating, spraying, etc. to provide conductivity. It may be used. Moreover, although the whole may be formed from a conductive material, at least a part of the surface of the conductive base material and / or the surface of the whole part immersed in water is conductive and can be energized. is required.
Examples of the metal and its oxide in the material of the conductive substrate include iron, aluminum, copper, titanium and their alloys, stainless steel, noble metals and their oxides. In particular, valve metals such as titanium, tantalum, and niobium having excellent corrosion resistance are preferable. Examples of the resin material include acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene copolymer, nylon, polyester, polystyrene, polycarbonate, polyethylene, polypropylene, vinyl chloride, polyethylene terephthalate, fiber reinforced plastic (FRP), and the like. It is done. Examples of inorganic materials include glass, alumina, zirconia, cement and the like.

When a metal is used as the conductive substrate, it can be used by coating or laminating with fine particles of a conductive substance in accordance with a commonly used method when producing a seawater electrolysis electrode, an oxygen generation electrode, or the like. When covering and laminating, it is necessary to consider such as improving the adhesion of the conductive base material to the base material.
In addition, when a non-conductive material such as a resin or an inorganic material is used as the base of the conductive base material, conductivity may be imparted by filling the material with fine particles of a conductive substance.
Examples of conductive fine particles include graphite, carbon black, carbon fine particles such as short fibers made of carbon fiber, gold, platinum, ruthenium, rhodium, palladium, iridium, alloys or oxides thereof, titanium, niobium, and tantalum. Valve metals such as oxides thereof and fine particles of oxides such as manganese oxide, cobalt oxide, tin oxide, antimony oxide, metal nitrides such as titanium nitride, zirconium nitride, vanadium nitride, tantalum nitride, niobium nitride, chromium nitride, Titanium carbide, zirconium carbide, vanadium carbide, niobium carbide, tantalum carbide, chromium carbide, molybdenum carbide, tungsten carbide and other metal carbides, titanium boride, zirconium boride, half boride, vanadium boride, niobium boride, boron Tantalum bromide, chromium boride Molybdenum boride, metal boride, such as tungsten boride, titanium silicide, zirconium silicide, niobium silicide, tantalum silicide, silicide vanadium include fine particles such as metal silicide such as tungsten silicide.
Furthermore, even if various potentials are applied to the surface of the conductive substrate, sterilized microorganisms, organic matter and scales that cannot be eliminated may adhere to the surface over a long period of time. In order to re-activate and reproduce the effect over a long period of time without subjecting to the above, platinum, ruthenium, rhodium, palladium, iridium, an alloy thereof or a substance having a minimal chlorine compound and a radical generating function Valve metal oxides such as oxides, titanium, niobium and tantalum, and oxides such as manganese oxide, cobalt oxide, tin oxide and antimony oxide can be used as conductive groups as single metal oxides, composite metal oxides or composite metal oxides. It is preferable to be present on the surface of the material. Further, these materials can be used as they are or after being molded.

  Alternatively, the conductive composition obtained by filling and dispersing the metal oxide fine particles in a binder resin may be coated on the surface of the non-conductive material substrate to impart conductivity. Examples of binder resins include fluororesins, acrylic resins, polyurethane resins, silicone resins, unsaturated polyester resins, acrylic-urethane resins, polyester-urethane resins, silicon-urethane resins, silicon-acrylic resins, epoxy resins, and thermosetting. Type rubber resin such as melamine-alkyd resin, melamine-acrylic resin, melamine-polyester resin, polyimide resin, or natural rubber, chloroprene rubber, silicon rubber, nitrile butylene rubber, polyethylene elastomer, polyester elastomer, polypropylene elastomer, etc. Is mentioned. The conductive composition may be formed as a coating layer by forming a conductive sheet and laminating the non-conductive substrate with an adhesive.

In addition to the fine particles of the conductive substance, a specific compound having an action of promoting an electron transfer reaction between a living cell and an electrode may be added. That is, aquatic organisms can be sterilized more efficiently by using an electron mediator that mediates electron transfer between a microorganism and an electrode together with a conductive material. Examples of electron mediators include ferrocene, ferrocene monocarboxylic acid, ferrocene dicarboxylic acid, or ferrocene such as [(trimethylamine) methyl] ferrocene and its derivatives, H ₄ Fe (CN) ₆ , K ₄ Fe (CN) ₆ , Na ferrocyanide such as ₄ Fe _{(CN) 6,} 2,6- dichlorophenol indole, phenanthryl methosulfate, benzoquinone, phthalocyanine, brilliant cresyl blue, Karoshianin, resorcinol, thionine, N, N-dimethyl - Soo Gandolfo native de・ Thionine, new methylene blue, tobucin blue O, safranin-O, 2,6-dichlorophenolindophenol, benzyl viologen, alizarin brilliant blue, phenocyanidinone, phenazine etsulfate, etc. And the like.
An example of the conductive substrate carrying such an electron mediator is a ferrocene modified electrode. By the way, when the oxidation peak current from the marine-adherent bacterium Vibrio arginolyticus is confirmed using a ferrocene-modified carbon electrode, the peak current is confirmed at 0.3 V vs SCE and can be sterilized at 0.4 V vs SCE.

Moreover, you may add the material which has antimicrobial property. Substances having antibacterial properties include those belonging to inorganic substances and those belonging to organic substances.
Examples of inorganic substances include metals such as silver, copper, nickel, zinc, lead, germanium, and oxides, oxyacid salts, chlorides, sulfates, nitrates, carbonates, and organic chelate compounds.
Examples of organic substances include 2- (4-thiazolyl) -benzimidazole, 4,5,6,7-tetrachloro-2-trifluoromethylbenzimidazole, 10,10′-oxysphenoxyarsine, trimethoxysilyl-propyloctadecylammonium Examples include chloride, 2-N-octyl-4-isothiazolin-3-one, and bis (2-pyridylthio-1-oxide) zinc.

Furthermore, a part or all of the conductive substrate is at least a single metal oxide, mixed metal oxide or composite metal oxide selected from titanium, titanium alloys and their oxides, platinum and / or metal oxides. You may use what consists of. By applying a potential to such a conductive substrate, by applying a positive potential without generation of oxygen or chlorine from water or seawater, aquatic organisms that directly or indirectly contact the surface of the conductive substrate By sterilizing, suppressing growth, and applying a potential to generate oxygen and chlorine, electrolytic substances such as chlorine compounds and oxygen are generated from water and seawater, and directly or indirectly on the surface of the conductive substrate Sterilization of contacted aquatic organisms and desorption cleaning of organic substances such as scales can be performed, and conductive substrates can be reactivated.
When the electrolyte is seawater, at least a single metal oxide selected from titanium, titanium alloys and their oxides, platinum and / or metal oxides so that the chlorine overvoltage is a positive potential lower than the oxygen overvoltage. Or it is preferable to comprise a mixed metal oxide or a composite metal oxide. In addition, in the case where the electrolytic solution is water that does not contain a chlorine compound, platinum and / or metal is used so that the oxygen overvoltage becomes a positive potential where a potential difference is recognized with respect to a potential at which a direct electron transfer reaction with a microorganism occurs. It is preferable to constitute a single metal oxide, mixed metal oxide or composite metal oxide selected from oxides. A material obtained by forming a conductive film from the above substance on a base of a conductive base material is also preferably used.

This conductive film can be composed of a metal or a compound thereof, specifically, any of platinum group metals, valve metals and their oxides, metal nitrides, metal carbides, metal borides, and metal silicides. can do. In particular, the metal oxide is at least one selected from titanium oxide, rhodium oxide, palladium oxide, ruthenium oxide, iridium oxide, manganese oxide, cobalt oxide, tin oxide and antimony oxide, niobium oxide, tantalum oxide and zirconium oxide, or It is preferably composed of two or more kinds.
In forming the conductive film, a method such as thermal spraying, sputtering, or ion plating can be employed.
Although metal oxides, metal nitrides, metal carbides, metal borides, and metal silicides have already been described, the materials described are only a part of them, and depending on the formation method, two or more types of metals may be included. There is no particular limitation because a part of the oxide is contained, two or more of these compounds are mixed, or the material of the conductive base material itself is air oxidized or anodized. These metal oxides, metal nitrides, metal carbides, metal borides, and metal silicides preferably have a thickness of 0.01 μm or more. The maximum thickness is not particularly limited, but may be set as appropriate depending on the formation method and purpose of use of the metal oxide, metal nitride, metal carbide, metal boride, and metal silicide.

When the conductive substrate is made of an electrochemically dissolved or corroded material such as iron, aluminum, copper, zinc, magnesium and their alloys, stainless steel, etc., the conductive substrate is formed on the surface in contact with the metal material. Corrosion resistance by providing an insulating resin coating layer, an insulating resin film layer, an insulating inorganic layer such as alumina or titania silicon oxide, or a valve metal such as titanium, niobium or tantalum between the conductive layer. Is preferable. The layer made of these materials may be formed as a single layer or two or more layers.
In particular, a conductive base material that is air-oxidized at a high temperature or normal temperature, such as titanium, which is a valve metal, or a material that is anodized by an electrolytic reaction can be used as a corrosion-resistant conductive material. Further, the corrosion-resistant conductive base material, and a metal oxidation which is made of porous platinum on a part or all of the surface of the corrosion-resistant conductive base material, or is three-dimensionally supported on the porous platinum and the porous platinum. And a conductive base material comprising a corrosion-resistant conductive base material, platinum that is dispersedly coated to such an extent that the surface of the corrosion-resistant conductive base material is partially exposed, and at least An intermediate layer comprising at least one metal oxide and / or a mixed metal oxide comprising at least one valve metal oxide covering the exposed portion of the surface of the corrosion-resistant conductive substrate, a noble metal oxide and a valve; What consists of an outer layer comprised from the mixed metal oxide layer which consists of at least 1 or more types of metal oxide chosen from the metal oxide is also preferable.

The shape of the conductive substrate is not particularly limited, and can be directly or indirectly contacted by directly adsorbing aquatic insects, their larvae, eggs, etc., and can be energized by arbitrarily setting a constant current when conducting a constant current. Or a potential applying a negative potential or a positive potential such that hydrogen is decomposed electrochemically to generate hydrogen, oxygen, chlorine, or the like.

The conductive substrate is connected to a power source and an output control device by lead wires. The power source and the output control device are devices for applying a direct current between the conductive base material and the paired electrodes, and have a function of converting polarity.
It is also possible to apply a constant potential or a constant current to the conductive substrate using a potentiostat or a galvanostat. The potentiostat and galvanostat that can be used are not particularly limited as long as a predetermined potential can be applied to the conductive base material, or a constant current can flow. In particular, it is preferable to implement a DC power supply device to which voltage control or current control and timing control means are added.

  The control device can also integrate a power source and an output control device. By integrating the power supply and output control device separately from the water system, there are problems such as the installation location of the power supply and output control device, and the handling of lead wires that electrically connect them with the water system. It can be overcome. Moreover, the problem of securing the power source can be overcome by using a battery as the power source.

  In order to integrate the power source and the output control device into the control device, a battery is used as the power source, and the output control board including the output control device is incorporated into the control device. For this purpose, it is necessary to make the portion for housing the output control board and the battery waterproof. Since it is preferable that the battery can be replaced, it is better to install at least an opening portion with a lid having a waterproof structure in which the battery can be taken in and out. For example, rubber packing and screwing may be used in combination. The output control board may be housed in the same space, sealed using a sealing material, etc., opened like a battery so that it can be accessed, and replaced or touched. It may not be possible. It is necessary to electrically connect the battery and the output control board, and the output control board and the conductive base material by lead wires or the like.

In executing the output control, it is possible to configure everything by an analog circuit and apply a constant voltage or a constant current, or apply a constant voltage or a constant current in the same way by combining a processor and an amplifier. It is possible to do so. By a program installed in the processor, it is possible to execute complicated output control such as applying a voltage or current only for a certain period of time or changing the applied voltage or current. In the case of a configuration using a reference electrode, it is also easy to measure the potential of the conductive substrate and perform feedback control based on it.

In the above configuration, a reference electrode can be used as necessary.
The reference electrode is used as a standard when measuring the potential of a conductive member that undergoes an electrochemical reaction. The reference electrode measures the potential difference between the reference electrode and the conductive substrate, and properly adjusts the potential of the conductive substrate with the power supply. It is to correct.
The reference electrode has a reversible electrode reaction on the surface of the reference electrode and responds according to the Nernst equilibrium potential equation with a certain chemical species in the electrolyte, and the potential is stable with respect to time. Returning to the above, a device that produces a constant potential when the temperature changes to a constant temperature is used. Examples thereof include a hydrogen electrode (NHE, RHE, platinum black electrode), a calomel electrode (SCE), a silver / silver chloride electrode (Ag / AgCl), a mercuric sulfate electrode, and a mercury oxide electrode.
In actual use, if the potential difference between the reference electrode and the conductive substrate is previously measured in the energized state, it is possible to know the energization conditions for suppressing adhesion and nesting of aquatic insects, their larvae and eggs. Therefore, it is not necessary to permanently install a reference electrode in the water system.

  The aqueous system in which the present invention is used is not particularly limited. Examples include seawater, river water, lake water, tap water, or aquatic aquarium water. In addition, the target organism is not particularly limited as long as it is an aquatic insect existing in the water. For example, it is desirable to adapt to organisms that are preferable to prevent adhesion as a power generation pest, such as insect larvae and eggs belonging to Tobikeras.

Next, control conditions will be described. As a control mode for energizing between two or more conductive substrates, constant voltage control or constant current control can be performed.
The constant current control conditions are as follows.
In order to control the adhesion prevention of aquatic insects, their larvae, or their nests by constant current control, the current value setting should be changed appropriately depending on the material and shape of the conductive substrate and the purpose of the conductive substrate maintenance state. Can do. In general, a current value of 50 mA / m ² or more is effective and may be 1 A / m ² or less. Preferably, 100 mA / m ² or more and 1 A / m ² or less may be used when an effect is expected by utilizing the fact that a water splitting reaction is involved. In particular, output of 100 to 400 mA / m ² is preferable because it can reduce power consumption and suppress material deterioration of the conductive base material functioning as an electrode, and can be used for a long time. In addition, each energization time can be appropriately selected and controlled depending on the purpose.
Furthermore, when the surface of the conductive base material is oxidized and the output voltage becomes high, the conductive base material is reduced and the output voltage is lowered by controlling the set current positively and negatively for an arbitrary time. Can keep. However, if the time during which a negative current is passed at a constant current is too long, the effect of preventing the adhesion of chickenpox insects, their larvae, or their nests may be reduced, so it is preferable to set appropriately depending on the conductive material used. The negative current value is also preferably selected and used depending on the conductive base material.

Similarly, when performing constant current control in the removal control when the chickenpox insect, its larva, or its nest adheres, it is expected that the effect will be manifested by utilizing the fact that it involves a water splitting reaction. 400 mA / m ² or more is required. Moreover, if it outputs exceeding 1000 mA / m < ² >, it is unpreferable at the point of the reduction of power consumption or the material deterioration of the electroconductive base material which functions as an electrode. Therefore, in order to long-term ^available, good minimum period of operation to the extent that the effect in the range of 400mA / ^{m 2} ~1000mA / m 2 is confirmed. Furthermore, when it is determined that a period during which a lot of chickenpox insects are observed, it is preferable to perform removal control from about one month before that period. Moreover, when combined with positive / negative reversal control, accumulation of inorganic substances existing in water on the electrode surface can be prevented and efficiently removed. For the control, it is preferable to appropriately select the adjustment ratio of the current amount as the polarity conversion time and the reaction amount. Further, when determining the control process throughout the year, it is possible to combine the process of controlling the adhesion prevention of the chickenpox insect, its larvae, or its nest and the process of removal control.

FIG. 1 shows a schematic configuration of an apparatus used for confirming the effect of the embodiment.
<Preparation of conductive substrate>
The procedure for producing the conductive substrates 1a and 1b used in the examples is shown below.
Conductive substrate 1a
A titanium substrate (corresponding to JIS type 2, t0.5 × w750 × L450 mm) was washed with alcohol, treated in an 8 wt% hydrogen fluoride aqueous solution at 20 ° C. for 2 minutes, washed with water and dried. Furthermore, it baked for 10 minutes in 600 degreeC air | atmosphere.
Conductive substrate 1b
A titanium substrate (corresponding to JIS type 2, t0.5 × w750 × L450 mm) was washed with alcohol, treated in an 8 wt% hydrogen fluoride aqueous solution at 20 ° C. for 2 minutes, washed with water and dried.
Next, 250 g of a powder obtained by weighing commercially available titanium powder and palladium powder to 65:35 (weight ratio) was mixed with a V-type mixer for 1 hour. A carbon die having 10 holes with a diameter of 10 mm is filled with 24 g of mixed powder in each hole, both ends are fixed with carbon punches, and a discharge plasma sintering machine (DR.SINTER) manufactured by Sumitomo Coal Mining Co., Ltd. is used. ) And sintered under the conditions of about 350 kgf / cm 2, pulse applied voltage 4 V, pulse applied current 3500 A, sintering temperature 800 ° C., sintering time 5 minutes. Then, surface polishing was performed to obtain a 65 wt% titanium-palladium (hereinafter referred to as Ti-Pd) discharge coating electrode having a diameter of about 10 mm and a length of 50 mm.
Subsequently, the titanium substrate from which the oxide film was removed was used as a cathode, and discharge coating was performed for 10 minutes in a glove box substituted with argon using a 65 wt% Ti—Pd electrode. Thereafter, the titanium base material subjected to electric discharge machining was cut into t1 × 10 × 10 mm with a fine cutter. When the surface of the titanium base material subjected to electric discharge machining was analyzed with a fluorescent X-ray analyzer for comparison with the discharge electrode, it was confirmed that the discharge electrode component was coated with an alloy of titanium and palladium. . When the elemental analysis of the cross section was performed with an electroprobe microanalyzer (hereinafter referred to as EPMA), the thickness of the titanium and palladium alloy layer was 30 to 50 microns.
A butanol solution of chlorinated iridium acid and an ethanol solution of tantalum chloride are mixed, and a coating solution containing 4.6 g / liter of iridium (Ir) and 50.0 g / liter of tantalum (Ta) (molar mixing ratio: 8Ir-92Ta) is prepared. Prepare and weigh 3.0 microliters per square centimeter with a micropipette, apply it onto the alloy layer of the titanium substrate on which the titanium and palladium alloy layers prepared above were formed, and then vacuum-dry at room temperature for 30 minutes And further baked in the atmosphere at 500 ° C. for 10 minutes. This process was repeated three times.
Next, in order to obtain an outer layer, a butanol solution of chloroiridate and an ethanol solution of tantalum chloride were mixed, and 50.0 g / liter of iridium (Ir) and 20.2 g / liter of tantalum (Ta) (molar mixing ratio: 70 Ir-30Ta). Then, the same process as described above was repeated 8 times using this coating liquid to obtain a conductive substrate.

Example 1
<Evaluation of energization condition and adhesion prevention effect to conductive substrate>
Conductive base materials 1a and 1b are installed in a river structure in a place with a large flow, and a 6-month energization test is performed under the control conditions 1 to 8 and the comparative control condition 1 shown below using a DC power supply device. did. At this time, the counter electrode 2 was iron (SS400, t10 × w20 × L300 mm), and the reference electrode 3 was a silver / silver chloride electrode.
After 6 months, the surface of the conductive substrate was visually evaluated and the change in the output voltage was observed.
Control condition 1: 50 mA / m ² always energized.
Control condition 2: 100 mA / m ² always energized.
Control condition 3: 200 mA / m ² always energized.
Control condition 4: 300 mA / m ² always energized.
Control conditions 5: 50mA / ^{m 2} at 180 minutes after energization by the polarity conversion -10 mA / ^{m 2} repeated 20 minutes energization.
Control conditions 6: 100mA / ^{m 2} at 180 minutes after energization by the polarity conversion -10 mA / ^{m 2} repeated 20 minutes energization.
Control conditions 7: 200mA / ^{m 2} at 180 minutes after energization by the polarity conversion -10 mA / ^{m 2} repeated 20 minutes energization.
Control conditions 8: 300mA / ^{m 2} at 180 minutes after energization by the polarity conversion -10 mA / ^{m 2} repeated 20 minutes energization.
Comparative control condition 1: 25 mA / m ² always energized.

In the control conditions 1 to 8 of Example 1, after 6 months, the surface of the electrode was free from adhesion and dirt (dust adsorbed to the nest of chickenpox insects) of the chickenpox insect, its larvae, or its nest. Also, the output voltage was stable without change.
In addition, the same effect was obtained when the installation location was performed on a lake with little or no flow under the same conditions as in Example 1.

Example 2
Conductive base materials 1a and 1b were installed in a river structure in a place with a large flow, and an energization test was conducted for 6 months under the control condition 9 shown below using a DC power supply. At this time, the counter electrode 2 was iron (SS400, t10 × w20 × L300 mm), and the reference electrode 3 was a silver / silver chloride electrode.
Control condition 9: 2.0 Vvs. After applying 180 minutes with Ag / AgCl, -0.0 to -0.1 Vvs. Ag / AgCl was applied for 20 minutes with an amplitude of 2 minutes, and positive and negative potential application was repeated.

After 6 months, the surface of the electrode was free of adhesion and soiling of chickenpox insects, their larvae, or their nests. Also, the output voltage was stable without change.
The same effect was obtained when the installation site was located on the lakeside with little or no flow under the same conditions as in Example 2.

<Desorption test>
Example 3
The conductive base materials 1a and 1b are installed in a river structure in a place with a large flow, immersed for 6 months, and after confirming the adhesion and contamination of aquatic insects, their larvae, or their nests, the DC power supply 4 is used. The energization test was conducted for 2 weeks under the following control conditions 10 to 15 and comparative control conditions 2 and 3. The counter electrode at this time was iron (SS400, t10 × w20 × L300 mm), and the reference electrode was a silver / silver chloride electrode.
Two weeks later, visual evaluation of the surface of the conductive substrate and observation of changes in output voltage were performed.
Control condition 10: 400 mA / m ² always energized.
Control condition 11: 600 mA / m ² always energized.
Control condition 12: 800 mA / m ² always energized.
Control conditions 13: 400mA / ^{m 2} at 180 minutes after energization by the polarity conversion -10 mA / ^{m 2} repeated 20 minutes energization.
Control condition 14: After energizing for 180 minutes at 600 mA / m ² , the polarity was changed, and energization was repeated for 20 minutes at −10 mA / m ² .
Control conditions 15: 800mA / ^{m 2} at 180 minutes after energization by the polarity conversion -10 mA / ^{m 2} repeated 20 minutes energization.
Comparative control condition 2: 50 mA / m ^{2 was} always energized, the polarity was changed, and energization was repeated at −10 mA / m ² for 20 minutes.
Comparative control condition 3: 100 mA / m ^{2 was} always energized, the polarity was changed, and energization was repeated at −10 mA / m ² for 20 minutes.

In Example 3, after 2 weeks under the control conditions 10 to 15, adhesion and dirt of the chickenpox insect, its larva, or its nest were removed from the surface of the electrode. Also, the output voltage was stable without change.
From this, it was confirmed that even when the control is stopped and the varicella insect is attached, it is possible to remove organisms and dirt by energizing the control range of +400 to +1000 mA / m ² . Further, when the control was performed at 600 mA / m ² or more, a desorption effect was obtained in one week. However, current control higher than 1000 mA / m ² can provide a stronger desorption effect, but it is necessary to consider electrode degradation.
In addition, the same effect was obtained when the installation location was performed on a lakeside with little or no flow under the same conditions as in Example 3.

Schematic configuration of the apparatus used for confirming the effect of the embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive base material 2 Counter electrode 3 Reference electrode 4 DC power supply device

Claims (5)

At least part of the water path is provided with two or more conductive base materials, arranged so as to function as electrodes, and energized between the conductive base materials, so A method for controlling adhesion and / or removal of aquatic insects, which comprises preventing and / or removing insects, their larvae, or their nests. 2. The method for controlling adhesion and / or removal of aquatic insects according to claim 1, wherein an amount of current flowing between the conductive base materials in the adhesion prevention control method is +50 mA / m ² or more. 2. The method for preventing and / or removing aquatic insects according to claim 1, wherein an amount of current flowing between the conductive substrates in the removal control method is +400 to +1000 mA / m ² . By energizing between the conductive substrates, by damaging at least a part of cells of aquatic organisms with a water splitting reaction, or by decomposing / denaturing an organic substance in contact with the conductive substrate 4. The method for preventing and / or removing adhesion of aquatic insects according to claim 1, wherein the adhesion is prevented and / or removed. The method for preventing and / or removing aquatic insects according to any one of claims 1 to 4, wherein a current flowing between the conductive bases is controlled to be reversed between positive and negative.

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