JP3925619B2 - Electrochemical antifouling method and apparatus - Google Patents

Description

【００５５】
殺菌効果の判定は、○は殺菌率８０％以上、△は殺菌率２０〜８０％、×は２０％未満を示す。また、短時間でも殺菌率が８０％を越えたことを確認できたものは、◎で表記した。尚、すべての基材に対して実施したものではない。
分解洗浄効果は、付着死細胞の有無を○は洗浄率８０％以上、△は洗浄率２０〜８０％、×は洗浄率２０％未満を示す。また、短時間でも洗浄率が８０％を越えたことを確認できたものは、◎で表記した。尚、すべての基材に対して実施したものではない。
【００５６】
実施例２
装置例１において、導電性基材として、上記導電性基材１〜２４を用い、図３、４に示した電位印加パターンにて実験を行った。その結果を表２に示す。
殺菌効果は、実施例１とほぼ同様の殺菌効率を示していたので、Ｔ１工程で０．９ＶｖｓＡｇ／ＡｇＣｌを３０分間印加し、死菌と生菌が混在して、付着している導電性基材を調整した。その後、図３に示した電位印加パターンでのＴ２電位は−０．６ＶｖｓＡｇ／ＡｇＣｌ、３０分間印加とし、図４に示した電位印加パターンＴ３の電位は、−０．３Ｖ〜−０．６ＶｖｓＡｇ／ＡｇＣｌ、３０分間印加し、電位を２分間隔で振幅させた。その際のＴ２工程及びＴ３工程の前後にて、死菌と生菌の総和である付着微生物数に対して、脱離した微生物数の比較し、減少比を求め、脱離効果を判定した。
【００５７】
【表２】

【００５８】
減少率は、○は減少率７０％以上、△は減少率３０〜７０％、×は３０％未満として示した。また、短時間でも減少率が８０％を越えたことを確認できたものは、◎で表記した。尚、その後Ｔ６工程を実施した導電性基材のすべてで洗浄効果が確認でき、組み合わせによる洗浄促進効果が期待できた。
【００５９】
実施例３
装置例１において、導電性基材として、上記導電性基材１〜２４を用い、図５、６に示した電位印加パターンにて実験を行った。その結果を表３に示す。
殺菌効果は、実施例１とほぼ同様の殺菌効率を示していたので、Ｔ１工程で０．９ＶｖｓＡｇ／ＡｇＣｌを３０分間印加し、死菌と生菌が混在して、付着している導電性基材を調整した。その後、Ｔ２電位は−０．６ＶｖｓＡｇ／ＡｇＣｌ、３０分間印加とした。次いで、図５に示した電位印加パターンでのＴ４の電設定を、−１．４ＶｖｓＡｇ／ＡｇＣｌ、６０分間印加とした。また、図６に示した電位印加パターンでのＴ５の電位設定を−０．３Ｖ〜−１．４ＶｖｓＡｇ／ＡｇＣｌ、６０分間印加とし、電位を２分間隔で振幅させた。Ｔ４及びＴ５工程の前後にて、付着していた有機物と見なした死菌体の存在有無によって、分解洗浄効果を判定した。
【００６０】
【表３】

【００６１】
分解洗浄効果は、付着死細胞の有無を○は洗浄率８０％以上、△は洗浄率２０〜８０％、×は洗浄率２０％未満を示す。また、短時間でも洗浄率が８０％を越えたことを確認できたものは、◎で表記した。尚、すべての基材に対して実施したものではない。また、その後Ｔ６工程を実施した場合、短時間で導電性基材のすべてでほぼ完全な洗浄効果が確認でき、組み合わせによる洗浄促進効果が期待できた。
【００６２】
＜生成物（塩素、酸素）発生の確認＞
導電性基材１，５、６、７，９，１１，２２について、海水５０ｍｌに浸し、１．６Ｖｖｓ．Ａｇ／ＡｇＣｌの電位を印加した場合の海水中の塩素濃度を測定した。電位を印加した海水中の塩素濃度は、残留塩素電極（９７−７０ＢＮ；Ｏｒｉｏｎ Ｒｅｓｅａｒｃｈ社製）を用いて測定した。電位印加後の海水を１０ｍｌサンプリングし、沃素試薬（Ｏｒｉｏｎ Ｒｅｓｅａｒｃｈ社製）及び酸試薬（ＯｒｉｏｎＲｅｓｅａｒｃｈ社製）をそれぞれ１００μｌ添加し、撹拌した。溶液を２分間放置した後、マルチメーター（８３ＭＵＬＴＩＭＥＴＥＲ；ＦＬＵＫＥ社製）を接続し残留塩素電極により電位を測定し、標準サンプルとの電極電位差から検量線を用いて塩素濃度を求めた。尚、塩素測定限界は、０．２ｐｐｍである。標準サンプルは、残留塩素標準液（Ｏｒｉｏｎ Ｒｅｓｅａｒｃｈ社製）、沃素試薬、酸試薬を各々１００μｌ混ぜ２分間撹拌した後、９９００μｌの蒸留水を添加し再度撹拌することにより作成した。
その結果、導電性基材１，５、６、１１について貴金属酸化物が導電性基材表面に存在する場合に、塩素発生を確認した。また、導電性基材、７，９，２２などの酸化物及びバルク金属では、水の分解に伴う酸素発生が確認され、ラジカル生成過程の存在が示された。
【００６３】
＜導電性基材の再活性化の検証＞
導電性基材５を例として、
（Ａ）電位を印加しない未使用の導電性基材５、
（Ｂ）１．０Ｖｖｓ．Ａｇ／ＡｇＣｌ、１００時間印加した導電性基材５、
（Ｃ）１．０Ｖｖｓ．Ａｇ／ＡｇＣｌ、１００時間印加した後、−１．４Ｖｖｓ．Ａｇ／ＡｇＣｌ、３０分印加した導電性基材５を用いて、電極活性としての塩素の発生を測定した。測定方法は前記塩素測定方法と同様に行った。
その結果、（Ａ）と（Ｃ）は、ほぼ同程度の塩素発生が確認された。しかし、（Ｂ）は、塩素発生の反応が（Ａ）と（Ｃ）より劣っていた。これは、１．０Ｖｖｓ．Ａｇ／ＡｇＣｌ、１００時間印加したことにより電極表面が酸化され塩素発生効率が低下したためと考えられる。従って、導電性材料により詳細な検討を必要とするが、少なくともＴ２，Ｔ３，Ｔ４及びＴ５における負電位を印加する事により、導電性基材を再活性化する事ができる。
また、導電性基材１においては、負電位の印加により、白金酸化物が還元され、白金の溶出が起こることが、反応電流量の減少として確認されている。しかし、それらを再びＴ１及びＴ６工程とすることで、安定した導電性を示し、再活性化された。従って、導電性基材表面に存在する物質によって、各工程を様々な組み合わせによりその性能を比較し、防汚効果を長期間安定させる必要がある。
【００６４】
＜走査型プローブ顕微鏡による酸化物形成及びその還元消失制御による導電性基材の再活性化確認の検証＞
導電性基材２２を代表例として、図５のタイミングチャートに合わせて電位を印加したときの電極表面を走査型プローブ顕微鏡（セイコーインスツルメンツ（株）製、ＳＰＩ３８００Ｎ）により観察を行った。印加条件は、Ｔ１が０．９Ｖｖｓ．Ａｇ／ＡｇＣｌ、９０分間、Ｔ２が−０．６Ｖｖｓ．Ａｇ／ＡｇＣｌ、４５分間、Ｔ４が−１．４Ｖｖｓ．Ａｇ／ＡｇＣｌ、１２０分間で行った。サンプルは電位を印加していない新規電極、Ｔ１印加終了時の電極、Ｔ４印加終了時の電極の表面状態観察を行った。
その結果、Ｔ１終了時には酸化被膜成長に伴う凹凸が見られたが、Ｔ４終了後のサンプルにはその凹凸が消滅しており、電位を印加していない電極表面とほぼ同じ状態に戻っていた。これより正電位印加により形成した酸化被膜は低い負電位を印加することにより電位を印加していない新規電極表面と同じ位に復元することがわかった。
【００６５】
【発明の効果】
本発明に係る電気化学的防汚方法によれば、被防汚面たる導電性基材の電極としての機能を維持向上すると共に、被防汚導電性基材の電気化学的防汚効果を長期に渡って安定的に得ることが可能となり、更に、脱離工程及び洗浄工程に関する自由度を高めることも可能となる。そして、本電気化学的防汚方法に基づいた装置は、導電性基材の交換などのコスト無く、再活性化させて長期間の防汚効果を再現させる事が可能であるので、極めて有用な装置である。
【図面の簡単な説明】
【図１】 実施例の装置の模式図である。
【図２】 電位制御のタイミングチャート図である。
【図３】 電位制御のタイミングチャート図である。
【図４】 電位制御のタイミングチャート図である。
【図５】 電位制御のタイミングチャート図である。
【図６】 電位制御のタイミングチャート図である。
【符号の説明】
１ 制御部
２ ポテンショスタット
３ 導電性基材
４ 参照極
５ 対極
６ 試験槽
７ 攪拌棒
８ 攪拌器
９ 正電位側電解生成物発生電位
１０ 負電位側電解生成物発生電位
Ｔ１ 電気化学的生成物を発生しない正電位印加工程
Ｔ２ 電気化学的生成物を発生しない負電位印加工程
Ｔ３ 電気化学的生成物を発生しない負電位領域での振幅電位印加工程
Ｔ４ 電気化学的生成物を発生する負電位印加工程
Ｔ５ 電気化学的生成物を発生する／しない負電位領域での振幅電位印加工程
Ｔ６ 電気化学的生成物を発生する正電位印加工程[0001]
BACKGROUND OF THE INVENTION
The present invention is an electrochemical method for electrochemically preventing organisms and scales from adhering to offshore structures, ships, water transportation pipes or waterways, fishing nets, heat exchangers, seawater intake screens, etc. The present invention relates to an antifouling method and an electrochemical antifouling apparatus using this method.
[0002]
[Prior art]
Many organisms exist in seawater and freshwater, and adhere to the surface of underwater structures, causing various problems. For example, when adhering to a ship or a buoy, a problem of increased propulsion resistance occurs. Moreover, when it adheres to the aquaculture ginger, problems such as inhibition of seawater exchange occur. Furthermore, problems such as deformation of nets occur when attached to fishing nets such as stationary nets.
In addition, microorganisms attached to the pipes and valves of water supply / drainage cause problems such as contaminating people and products through seawater and fresh water.
The general mechanism of biological attachment to the surface of structures in contact with seawater and fresh water is as follows.
First, adherent gram-negative bacteria adsorb to the surface of the structure and secrete a large amount of slime-like substances derived from lipids. Furthermore, Gram-negative bacteria gather and grow in this slime layer to form a microbial coating. In the seawater, large organisms such as algae, shellfish, and barnacles, which are large organisms, adhere to the microbial coating. The attached large creatures will breed and grow, eventually covering the surface of the underwater structure.
As an antifouling means against contamination by organisms adhering to the surface of the above-mentioned underwater structures and seawater or fresh water, a sterilizing substance is added to the antifouling surface, or a paint containing an organotin compound In general, a method of forming a coating film and eluting an organotin compound and a method of antifouling using chlorine generated by electrolyzing seawater have been performed. However, these methods generate harmful substances, and there is a concern about the impact on the organism due to water pollution.
[0003]
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 microbial membrane, thereby killing the microorganism (Japanese Patent Publication No. 6-91821). Incidentally, in the marine-adherent bacterium Vibrio arginolytics used in the present invention, an oxidation peak current can be confirmed at 0.7 V vs SCE. In other words, since the predetermined potential at which direct electrochemical reaction with microorganisms is confirmed occurs below the decomposition potential of water or seawater as the electrolyte, there is no production of chemical substances and only microorganisms that adhere to the conductive substrate are sterilized. Then, attachment of aquatic organisms thereafter can be prevented. Therefore, it has been shown that this is an excellent antifouling method that is free from marine pollution and has no effect on the ecosystem of marine organisms.
Japanese Patent Application Laid-Open No. 11-19249 discloses a step of applying a positive potential to a conductive substrate in water to adsorb and sterilize microorganisms in the water on the surface of the conductive substrate; A step of destroying microorganism cells adsorbed on the surface of the conductive substrate by applying a higher positive potential, and detaching the sterilized microorganisms adhered to the conductive substrate and their decomposition products; An invention having a gist of a method for controlling an underwater microorganism characterized by the above is described. Further, in Japanese Patent No. 3105024, in water, a positive potential is applied to the conductive substrate to adsorb and sterilize microorganisms in water on the surface of the conductive substrate (+0 to 1.5 V vs SCE), A step of detaching sterilized microorganisms adsorbed on the surface of the conductive substrate by applying a negative potential to the conductive substrate (−0 to 0.4 V vs. SCE). An invention based on the control method is described. JP 2001-198572 A discloses a step of adsorbing and sterilizing microorganisms in water on the surface of the conductive substrate by applying a positive potential that does not cause electrolysis to the conductive substrate in water. A negative potential that causes electrolysis is applied to the conductive substrate to reduce the surface of the conductive substrate, and at the same time, sterilized microorganisms that induce an alkaline substance on the surface of the conductive substrate and are adsorbed on the surface of the conductive substrate and their decomposition And a process for detaching substances, which describes a method for controlling an underwater microorganism.
Further, as an approximate antifouling method, a method for generating antifouling by generating oxygen on a conductive substrate is disclosed in Japanese Patent Publication No. 1-46595 and Japanese Patent Application Laid-Open No. 11-303041. In these methods, the oxygen generation potential is set to a range of about 0.55V to 1.1V. However, the electrochemical antifouling method clarifies that microorganisms can be sterilized only when the cell and the conductive substrate are in direct contact, whereas the approximate antifouling method has almost the same potential. There is no clear proof that oxygen generated in can sterilize and antifoul microorganisms that do not contact the conductive substrate. Therefore, it is difficult to conceptually separate from the electrochemical antifouling method that microorganisms do not adhere to the conductive substrate.
Further, antifouling methods for generating hypochlorite ions and chlorine ions by applying a positive potential to the conductive coating film are described in Japanese Patent Publication No. 6-15069 and Japanese Patent Publication No. 8-14036. The antifouling effect of the chlorine injection method by the seawater electrolyzer is considered to be generated directly on the surface to be protected.
[0004]
[Problems to be solved by the invention]
The method of sterilizing and preventing the adhesion of microorganisms by applying a potential that does not cause electrolysis of seawater or water to the conductive base material to be antifouling is free from marine pollution, and also the marine organism ecosystem It is an excellent antifouling method because it has no effect on the surface.
By the way, the above-mentioned electrochemical antifouling method was sterilized by applying a positive potential that does not cause electrolysis of seawater or water to sterilize adhering microorganisms, and applied a negative potential that does not cause electrolysis of seawater or water. It consists of a step of removing microorganisms, charged organic substances and scales, and a step of washing and reducing the surface to be protected by applying a negative potential that causes electrolysis of seawater and water. In the electrochemical antifouling method, in order to maintain the effect for a long period of time, it is necessary to sufficiently perform the sterilization process for the conductive base material which is the antifouling surface in the cleaning process. On the other hand, during the cleaning process, the sterilization process and the desorption process cannot be performed, and precipitation of magnesium hydroxide or the like occurs on the surface of the conductive base material, thereby inhibiting the electron transfer reaction. The time distribution of each process needs to be changed according to the environment, and it is difficult to achieve optimal distribution. In addition, when the conductive base material, which is the surface to be protected, is excessively oxidized, there is a decrease in the electron transfer speed between the microorganism and the conductive base material due to an increase in the electrical resistance value on the surface of the conductive base material. May occur or it may be difficult to apply the set potential uniformly to the entire conductive substrate. Further, the surface of the conductive base material has many problems in practical use in the future, such as a decrease in function as an electrode due to deterioration of a constituent material.
The present invention has been made in view of these problems, and while maintaining and improving the function as an electrode of a conductive substrate as a surface to be protected, the electrochemical antifouling effect of the conductive substrate to be protected is long-term. It is an object to increase the degree of freedom regarding the desorption step and the washing step for the purpose of obtaining stably over the range.
[0005]
[Means for Solving the Problems]
The present invention comprises at least a conductive substrate, a counter electrode, and a power source that applies a voltage between the conductive substrate and the counter electrode, and utilizes a direct electron transfer reaction between the conductive substrate and a living organism. In the electrochemical antifouling method, the conductive substrate has at least a part of the antifouling surface at least.The following A) and B),
A) Platinum group metal selected from platinum, ruthenium, rhodium, palladium and iridium
B) Single metal oxide or mixed metal oxide or composite metal oxide selected from oxides of platinum, ruthenium, rhodium, palladium, iridium, titanium, zirconium, niobium, tantalum, manganese, cobalt, tin, and antimony
The power source applies at least a positive potential that does not generate a product electrochemically from the electrolyte to the conductive substrate, thereby suppressing the growth of aquatic organisms that directly or indirectly contact the surface of the conductive substrate. The first gist is an electrochemical antifouling method characterized byIt consists of at least a conductive substrate, a counter electrode, and a power source that applies a voltage between the conductive substrate and the counter electrode, and is an electrochemical device that utilizes a direct electron transfer reaction between the conductive substrate and a living organism. In the antifouling method, the conductive base material is a single metal oxide, mixed metal oxide, or composite metal oxide in which a part or all of the antifouling surface is selected from at least platinum and / or metal oxide. A positive potential that does not generate an electrochemically generated product from the electrolyte in at least the conductive substrate by the power source, and aquatic organisms that are in direct or indirect contact with the surface of the conductive substrate. An aquatic organism that directly or indirectly contacts the surface of the conductive substrate by suppressing the growth and further applying a positive potential that electrochemically generates a product from the electrolyte to the conductive substrate. And scale detachment The second aspect is an electrochemical antifouling method comprising a step of cleaning and reactivating the conductive base material, and electrochemically generating a product from the electrolyte on the conductive base material In the step of desorbing and cleaning the aquatic organisms and scale that directly or indirectly contact the surface of the conductive substrate and reactivating the conductive substrate by applying a positive potential to be applied, The electrochemical antifouling method according to the second aspect, characterized in that a chlorine compound or a radical is generated, is further provided as a third aspect, and the conductive base material is electrochemically applied from an electrolyte solution. The gist of any one of the first to third aspects, comprising a step of detaching aquatic organisms that directly or indirectly contact the surface of the conductive substrate by applying a negative potential that does not generate a product. Electrochemical antifouling method as described in According to a fourth aspect of the present invention, an aquatic material that directly or indirectly contacts the surface of the conductive substrate by applying a negative potential that electrochemically generates a product from the electrolyte to the conductive substrate. The electrochemical antifouling method according to any one of the first to fourth aspects, including a step of desorbing and cleaning organisms and scales, is used as a fifth aspect, and the conductive substrate is also used as a counter electrode. A sixth aspect is the electrochemical antifouling method according to any one of the first to fifth aspects, characterized in that the conductive base material is a valve metal of a corrosion-resistant conductive base material. , Platinum or rhodium, palladium, ruthenium, iridium, manganese, cobalt, tin, antimony, three-dimensionally supported on porous platinum and porous platinum on a part or all of the surface of the corrosion-resistant conductive substrate, Niobium, Tantalum, Zirconium A coating layer comprising a single metal oxide, mixed metal oxide or composite metal oxide selected from oxides of titanium and titanium; The electrochemical antifouling method according to any one of the seventh aspect, wherein the conductive substrate is a valve metal of a corrosion-resistant conductive substrate, and a surface of the corrosion-resistant conductive substrate is partially exposed. It is composed of platinum that is dispersed and coated to the extent and at least one metal oxide of iridium, manganese, cobalt, tin, antimony, niobium, tantalum, zirconium, and titanium that covers at least the exposed portion of the surface of the corrosion-resistant conductive substrate. An intermediate layer composed of a mixed metal oxide and a noble metal oxide of platinum, rhodium, palladium, ruthenium, iridium and a valve metal oxide of niobium, tantalum, zirconium, titanium. The electrochemical protection according to any one of the first to sixth aspects, characterized by comprising an outer layer composed of a mixed metal oxide layer comprising at least one selected metal oxide. The eighth aspect is the fouling method,An aquatic organism that is in direct or indirect contact with the surface of the conductive base material and the conductive material, comprising at least a conductive base material, a counter electrode, and a power source that applies a voltage between the conductive base material and the counter electrode. An electrochemical antifouling device for controlling a direct electron transfer reaction with a conductive substrate, wherein a positive potential for electrochemically generating a product from an electrolyte is applied to the conductive substrate, A process for detaching and cleaning aquatic organisms and scales that directly or indirectly contact the surface of the conductive substrate and reactivating the conductive substrate can be set. The material has a positive potential at which no electrochemical product is generated from the electrolytic solution, a negative potential at which no electrochemical product is generated from the electrolytic solution, and a negative potential at which the electrochemical product is generated from the electrolytic solution. Potential can be set arbitrarily and can be applied periodically The electrochemical stain and wherein the doorNinth summaryAnd
[0006]
Hereinafter, the present invention will be described in detail.
The basic antifouling function expression configuration in the electrochemical antifouling method according to the present invention is:
(1) Sterilization step: a step of sterilization by applying a positive potential that does not electrochemically generate a product from the electrolyte solution to the conductive substrate (+0 to 1.5 V vs SCE);
(2) Desorption step: A negative potential that does not generate a product electrochemically from the electrolyte solution is applied to the conductive substrate, and the aquatic organisms and scales that are directly or indirectly attached and contacted by an electrostatic function. A desorption step (−0 to −0.6 V vs SCE);
(3) Washing and reducing step: Applying a negative potential to electrochemically generate a product from the electrolytic solution to the conductive substrate, alkaline decomposition and washing of aquatic organisms and scales attached to and contacted the conductive substrate Reducing the conductive substrate surface (−0.6 to −2.0 V vs SCE);
(4) Decomposition cleaning reactivation step: A positive potential for electrochemically generating a product from the electrolytic solution is applied to the conductive base material, and the conductive base material is directly or indirectly adhered to and contacted with the surface of the conductive base material. Steps of decomposing and cleaning aquatic organisms and scales by generating chlorine compounds or radicals, cleaning the surface of the conductive substrate, and reactivating (positive potential higher than +1.5 V vs SCE)
Of these, at least any process including the sterilization process is performed on the conductive substrate that is the surface to be protected, and the load on water and seawater caused by the most chemically generated chemical substances is minimal, and stable long-term prevention It is intended to obtain a dirty effect.
However, these potentials can be changed depending on the conductive substrate and counter electrode material to be used and the combination thereof and the reference electrode for measuring the reference potential of water or seawater. For example, as a reference electrode, a reference electrode generally used for electrochemical measurement such as SCE (saturated citrus electrode) or Ag / AgCl (silver / silver chloride electrode) can be used.
[0007]
Next, potential application conditions in each step will be described.
(1) Sterilization process
When a positive potential is applied to the conductive substrate in water containing aquatic organisms, the aquatic organisms in the water are adsorbed on the surface of the substrate. Furthermore, the positive potential applied to the substrate has an action of electrochemically sterilizing aquatic organisms adsorbed and contacted to the substrate surface. That is, aquatic organisms are adsorbed on the substrate surface by a positive potential and sterilized on the surface. At this time, the set potential is a potential at which no product is generated electrochemically from the electrolytic solution, and is a potential equal to or lower than the generation potential of oxygen and chlorine accompanying the decomposition of water and seawater.
The preferred potential is +0 to 1.5 V vs. SCE, more preferably +0.5 to +1.2 Vvs. SCE. However, this potential depends on the physical properties of the conductive base material used. If the potential is lower than the generation potential of oxygen and chlorine accompanying water decomposition, contamination of water and seawater by electrolytic products is not possible. It can be suppressed to a minimum and can exhibit a stable antifouling effect over a long period of time. Also, +0 Vvs. If it is less than the positive potential at which direct electron transfer reaction with microorganisms is confirmed from SCE, aquatic organisms cannot be adsorbed on the substrate and sterilized, but the potential is intermittently considered in consideration of deterioration and consumption of the conductive substrate. Is preferably varied.
The time for applying a positive potential at which no product is generated electrochemically from the electrolytic solution can be appropriately selected depending on the characteristics of the conductive substrate. Generally, it varies depending on the durability of the conductive substrate and the amount of aquatic organisms that are in direct or indirect contact with the surface of the conductive substrate. If it is maintained, it is preferably set as long as possible in order to reduce the load on the water and seawater by the electrolytically generated chemical substance. Depending on the conductive base material, application for 0.5 to 18 hours is more preferable depending on the rate of formation of the oxide.
(2) Desorption process
Next, when a negative potential is applied to the surface of the conductive substrate, aquatic organisms and scales that are in direct or indirect contact with each other are detached. The negative potential at which no product is electrochemically generated from the electrolyte is 0 to -1.0 Vvs. Ag / AgCl. Preferably, −0 to −0.6 Vvs. Ag / AgCl.
At that time, aquatic organisms, other cells, cells of sterilized aquatic organisms and / or damaged or organic matter adhered to the conductive base material may have a pH on the surface of the conductive base material due to electrostatic mechanism or potential fluctuation. Desorbed due to fluctuations.
Furthermore, desorption and washing can be made more efficient by changing the potential at the negative potential. The width of the varying potential is preferably about −0.3 V to −0.9 V, and the period is preferably 10 Hz to 0.001 Hz.
The time for applying a negative potential at which no product is electrochemically generated from the electrolytic solution can be appropriately selected depending on the characteristics of the conductive substrate. Generally, about 0.1 to 24 hours is preferable although it varies depending on the durability of the conductive substrate and the amount of attached aquatic organisms directly or indirectly contacting the surface of the conductive substrate. In consideration of deterioration of the conductive substrate, application for 0.1 to 2 hours is more preferable.
[0008]
(3) (Washing reduction process)
Furthermore, the negative potential at which an electrochemical product is generated from an electrolyte such as water or seawater is −1.0 Vvs. More negative potential than Ag / AgCl, preferably -1.0 V to -2.0 Vvs. It is about Ag / AgCl. By applying this negative potential, detachment of aquatic organisms, other cells, sterilized aquatic organism cells attached to the conductive substrate and / or damaged or organic matter thereof is promoted. When a negative potential is generated that electrochemically generates a product from the electrolyte, hydrogen is generated on the surface of the conductive substrate due to the decomposition of the electrolyte, and this hydrogen removes deposits on the surface of the conductive substrate. It is to be done. Moreover, pH becomes alkaline in the vicinity of the conductive substrate. Furthermore, the precipitation of hydroxide may occur due to the strong alkali atmosphere, and it is necessary to appropriately select the potential to be applied and the application time. However, the organic substance is dissolved by the hydroxide. By removing and dissolving them, the surface of the conductive substrate is cleaned. In some cases, it is necessary to reduce the oxide on the surface of the conductive substrate, reduce the oxide that inhibits the electron transfer reaction at the interface of the conductive substrate, and maintain and recover the function of the sterilization process. Furthermore, desorption and washing can be made more efficient by changing the potential at the negative potential. The width of the varying potential is preferably about −0.3 V to −2 V, and the period is preferably 10 Hz to 0.001 Hz.
The time for applying the negative potential at which the product is generated electrochemically from the electrolyte can be appropriately selected depending on the characteristics of the conductive substrate. Generally, it is preferably about 0.5 to 24 hours, although it varies depending on the durability of the conductive substrate and the amount of attached aquatic organisms that directly or indirectly contact the surface of the conductive substrate. In consideration of deterioration of the conductive substrate, application for 0.5 to 2 hours is more preferable.
(4) (Decomposition cleaning reactivation process)
The positive potential at which the product is electrochemically generated from the electrolyte is a potential at which oxygen or chlorine is generated as water or seawater decomposes, and is +1.5 Vvs. This is clearly confirmed by the potential exceeding the SCE. When these high potentials are applied for a long time, water and seawater are likely to be electrolyzed to generate chlorine and unknown substances, and the conductive base material may be deteriorated. In particular, it may be inappropriate to maintain the antifouling effect and to minimize the contamination of water and seawater by electrolytic products. However, in the present invention for the purpose of long-term antifouling, sterilized microorganisms, organic substances and scales that cannot be excluded even when various potentials are applied to the surface of the conductive base material that becomes the antifouling surface may adhere. In order to reactivate them without reproducing the conductive substrate and reproduce the long-term antifouling effect, it is preferable to control the minimum necessary chlorine compound and radical generation function.
Incidentally, when the physical property of the surface of the conductive base material is such that the chlorine overvoltage is lower than the oxygen overvoltage, the generation of a chlorine compound occurs, and in the opposite case, the phenomenon that oxygen is generated first can be confirmed. Examples of the chlorine generating substrate include noble metals and oxides thereof. Examples of the oxygen generating substrate include valve metals, oxides thereof, and cobalt oxide.
The time for applying a positive potential for electrochemically generating a product from the electrolyte can be selected as appropriate depending on the characteristics of the conductive substrate. In general, it depends on the durability of the conductive substrate and the amount of aquatic organisms that are in direct or indirect contact with the surface of the conductive substrate. It is preferable to make settings for minimization. Considering this point, it is more preferable to apply about 0.5 to 24 hours per month. Moreover, it is also possible to install and operate in the time of about 1/10 to 1 / 10,000 compared with the set time of the sterilization process of (1).
[0009]
In the present invention, in order to minimize the contamination of water and seawater by chemical substances and maintain the antifouling effect over a long period of time, the above (1) sterilization step, (2) desorption step, and (3) cleaning reduction Each step of the step and (4) decomposition cleaning reactivation step can be periodically applied in an arbitrary order and frequency according to the situation after appropriately setting the applied potential and the applied time.
[0010]
The conductive base material used in the present invention may be entirely formed of a conductive material, but at least a part of the surface of the conductive base material which is an antifouling surface and / or a part immersed in water. It is necessary that the surface is conductive and can be energized.
The conductive substrate is not particularly limited as long as it is made of a metal, an oxide thereof, a resin, or an inorganic material and has a function of maintaining the structure. Examples of the metal material include iron, aluminum, copper, and alloys thereof, stainless steel, noble metals and oxides thereof. 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.
[0011]
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 conductive base material, the material may be provided with conductivity by filling the material with fine particles of a conductive substance and forming the base material.
Examples of conductive fine particles include graphite, carbon black, carbon fine particles such as short fibers made of carbon fiber, valves such as gold, platinum, ruthenium, rhodium, palladium or their noble metal oxides, titanium, niobium, tantalum, etc. Metal or oxides thereof and fine particles of oxides such as manganese oxide, cobalt oxide, tin oxide, antimony oxide, titanium nitride, zirconium nitride, vanadium nitride, tantalum nitride, niobium nitride, chromium nitride metal nitrides, titanium carbide, Metal carbides such as zirconium carbide, vanadium carbide, niobium carbide, tantalum carbide, chromium carbide, molybdenum carbide, tungsten carbide, titanium boride, zirconium boride, half boride, vanadium boride, niobium boride, tantalum boride, Chrome boride, molybdate Den, metal borides 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.
Further, in the present invention for the purpose of long-term antifouling, sterilized microorganisms, organic matter and scales that cannot be eliminated even when various potentials are applied may adhere to the surface of the conductive base material that becomes the antifouling surface. In order to re-activate them and reproduce the long-term antifouling effect without the cost of replacing the conductive substrate, etc., the surface of the conductive substrate having the minimum chlorine compound and radical generation function is required. There are single metals such as platinum group oxides such as platinum, ruthenium, rhodium and palladium, valve metal oxides such as titanium, niobium and tantalum, and oxides such as manganese oxide, cobalt oxide, tin oxide and antimony oxide. It is preferably used as an oxide, a composite metal oxide or a composite metal oxide. Further, these materials can be used as they are or after being molded.
[0012]
Alternatively, the conductive composition obtained by filling and dispersing fine particles of the conductive material 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 nonconductive substrate via an adhesive.
[0013]
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_FourFe (CN)₆, K_FourFe (CN)₆, Na_FourFe (CN)₆Ferrocyanines such as 2,6-dichlorophenolindole, phenanthine methosulfate, benzoquinone, phthalocyanine, brilliant cresyl blue, calocyanine, resorcin, thionine, N, N-dimethyl-disulfonated thionin, new methylene blue, Tobucin blue O, safranin-O, 2,6-dichlorophenol indophenol, benzyl viologen, alizarin brilliant blue, phenocyanidinone, phenazine etsulfate 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 used in the present invention 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. .
[0014]
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.
[0015]
In particular, a part or all of the antifouling surface of the substrate is composed of at least a single metal oxide, mixed metal oxide or composite metal oxide selected from platinum and / or metal oxide, and oxygen from water or seawater. By applying a positive potential without generation of chlorine and chlorine, it sterilizes aquatic organisms that are in direct or indirect contact with the surface of the conductive substrate, suppresses growth, and releases chlorine compounds or radicals from water or seawater. Substances that can be generated and removed from aquatic organisms and scales that are in direct or indirect contact with the surface of the conductive substrate and can be reactivated, and the conductive substrate can be used as a counter electrode. And a conductive film is preferably used.
In addition, when the electrolyte is seawater, a single metal oxide, mixed metal oxide, or mixed metal oxide selected from platinum and / or metal oxide so that the chlorine overvoltage is a positive potential lower than the oxygen overvoltage. In the case where the electrolytic solution is water containing no chlorine compound, a single metal selected from platinum and / or metal oxide so that the oxygen overvoltage is a positive potential lower than the chlorine overvoltage. It is preferable to constitute an oxide, a mixed metal oxide or a composite metal oxide.
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 platinum 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. 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 or two or more of these compounds are mixed. These metal oxides, metal nitrides, metal carbides, metal borides, and metal silicides may be films having a thickness of 0.1 μm or more, and the maximum thickness is not particularly limited. What is necessary is just to set suitably according to the formation method and purpose of use of nitride, metal carbide, metal boride, and metal silicide.
[0016]
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. It is preferable to provide 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. . The layers made of these materials may be formed as a single layer or two or more layers. In particular, the conductive substrate is made of a corrosion-resistant conductive substrate and porous platinum on a part or all of the surface of the corrosion-resistant conductive substrate, or the porous platinum and the porous platinum are three-dimensionally formed. A coating layer composed of a metal oxide supported on the substrate, and a conductive base material, in which the conductive base material is dispersed and coated to such an extent that the surface of the corrosion-resistant conductive base material is partially exposed. An intermediate layer made of platinum and a mixed metal oxide comprising at least one or more metal oxides and / or valve metal oxides covering at least an exposed portion of the surface of the corrosion-resistant conductive substrate; It is preferable to use an outer layer composed of a mixed metal oxide layer made of at least one metal oxide selected from noble metal oxides and valve metal oxides.
[0017]
The shape of the conductive substrate is not particularly limited, and can efficiently adsorb aquatic organisms and directly or indirectly contact them to apply a potential, and can perform the above (4) decomposition cleaning reactivation step If it is.
[0018]
The antifouling device of the present invention is provided with a counter electrode so as not to contact the conductive substrate. It is preferable that the counter electrode base material can be the same as that of the conductive base material, but it can be appropriately selected and can be appropriately selected depending on the physical properties and shape of the surface to be protected.
[0019]
The conductive base material and the counter electrode are connected to the power supply device by lead wires. This power supply device is a device that supplies a direct current between a conductive base material and a counter electrode, and has a function of converting polarity. In addition, if there are only a few organisms that live in water or seawater to the extent that antifouling can be maintained simply by carrying out the above (1) sterilization step, a constant current generator (galvanostat) may be used. .
[0020]
In addition to the above configuration, a reference electrode may be used as necessary, or a constant potential or a constant current may be applied to the conductive substrate using a potentiostat or a galvanostat.
The reference electrode, the potentiostat, and the galvanostat that can be used are not particularly limited as long as a predetermined potential can be applied to the conductive substrate 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.
Moreover, as for the electrode arrangement | positioning which forms an electrolytic cell, the installation position of a counter electrode is not limited with respect to a working electrode. The reference electrode is preferably installed in the vicinity of the working electrode, but the reference electrode should not be used when the current value when the antifouling effect is manifested between the conductive substrate and the counter electrode is clear. There is no problem.
[0021]
The electrolytic solution that can be treated according to the present invention is not particularly limited as long as it is water containing aquatic organisms. Examples include seawater, river water, lake water, tap water, drinking water, and various buffer solutions. Also, the target organism is not particularly limited as long as it is an organism present in the water.
[0022]
[Action]
The present invention relates to an electrochemical antifouling method using a direct electron transfer reaction between a conductive substrate and a living organism, and an apparatus using this method, wherein the conductive substrate is a part or all of its antifouling surface. Is composed of at least a single metal oxide, mixed metal oxide or composite metal oxide selected from platinum and / or metal oxide, so that (1) sterilization step, (2) desorption step, (3) washing In each step of the reduction step and (4) decomposition cleaning reactivation step, the applied potential and the application time are appropriately set, and can be periodically applied in any order and frequency depending on the situation. In addition to minimizing the contamination of water and seawater due to water, maintaining and improving the function of the conductive substrate, which is the surface to be protected, as an electrode, the electrochemical antifouling effect of the conductive substrate to be protected over a long period of time And obtain it stably.
[0023]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
<Device Example 1>
FIG. 1 is a schematic view of an apparatus used in the following examples.
In the test tank 6, a conductive substrate 3, a reference electrode 4, and a counter electrode 5 are disposed. The potentiostat 2 is individually connected to each of the conductive substrate 3, the reference electrode 4, and the counter electrode 5. The test tank 6 contains sterilized seawater, and a stirrer 8 and a stirring bar 7 are disposed at the bottom thereof. The reference electrode 4 was a saturated sweet potato electrode (SCE), and the counter electrode 5 was an electrode formed of a conductive material.
The controller 1 outputs an instruction value of the applied potential to the reference electrode 4 of the conductive base material 3 in an analog manner, and the potentiostat 2 causes the potential of the conductive base material 3 to the reference electrode 4 to be an analog input value. The voltage is output to the conductive substrate 3 and the counter electrode 5. In order to change the potential, the control unit 1 outputs an analog output of the indication value of the applied potential with a time resolution of at least 100 Hz, preferably 1 kHz or more. Furthermore, the potentiostat 2 responds to the analog input value of the potential accordingly with a response performance of at least 100 Hz, preferably 1 kHz or more.
The control unit 1 includes a circuit configured by a CPU, an input / output port, a digital / analog converter, and a memory (not shown) such as a ROM or a RAM. A control program and a timing chart for control to be described later are incorporated in the ROM, and the CPU converts the potential indication value into an analog value by a digital / analog converter according to the control program and the timing chart, and outputs the result to the potentiostat 2. . By using a one-chip computer incorporating the above-described components in the control unit 1, the overall circuit configuration can be simplified and made inexpensive.
[0024]
Next, the potential control timing chart shown in FIGS. 2 to 6 will be described in detail. In the timing chart, the horizontal axis represents time, and the vertical axis represents the indicated value of the potential with respect to the reference electrode 4 of the conductive substrate 3. Here, a combination of the following four types of steps (six potential application steps) is explicitly illustrated as a timing chart, but other steps depending on how to apply a potential are not specifically excluded.
(1) (Sterilization step) Positive potential application step (T1) that does not generate an electrochemical product: A step of applying a positive potential lower than the positive potential side electrolysis product generation potential 9. The potential value to be applied can be changed depending on the process.
(2) (Desorption step) Negative potential application step (T2) that does not generate electrochemical products or amplitude potential application step (T3) in a negative potential region that does not generate electrochemical products: Both steps are negative A negative potential higher than the potential side electrolytic product generation potential 10 is applied. In the amplitude potential application step (T3), the applied potential is changed almost continuously. Depending on the responsiveness of the system, it is possible to give a potential changed in a trapezoidal wave instead of a triangular wave as the indication potential.
(3) (Washing reduction step) A negative potential applying step (T4) for generating an electrochemical product, or an amplitude potential applying step in a negative potential region where an electrochemical product is generated and / or a negative potential region where no electrochemical product is generated ( T5): In both steps, a negative potential lower than the negative potential side electrolysis product generation potential 10 is applied.
(4) (Decomposition cleaning reactivation step) Positive potential application step (T6) for generating an electrochemical product: A positive potential higher than the positive side electrolysis product generation potential 9 is applied.
In the potential application pattern shown in the timing chart of FIG. 2, the positive potential application step (T1) that does not generate an electrochemical product and the positive potential application step (T6) that generates an electrochemical product are alternately repeated. The application potential and application period of each process can be determined appropriately according to the case. For example, a pattern in which a plurality of different potential values are applied in the positive potential application process (T1) that does not generate an electrochemical product can be created. It is.
In the potential application pattern shown in the timing chart of FIG. 3, a positive potential application step (T1) that does not generate an electrochemical product, a negative potential application step (T2) that does not generate an electrochemical product, and an electrochemical product. The positive potential applying step (T6) for generating is alternately repeated. The applied potential and the application period in each step can be appropriately determined according to circumstances, and the order and frequency are also arbitrary. For example, a positive potential application step (T1) that does not generate an electrochemical product and a negative potential application step (T2) that does not generate an electrochemical product are alternately repeated a certain number of times, and then an electrochemical product is generated. A pattern of applying the positive potential applying step (T6) can be created.
In the potential application pattern shown in the timing chart of FIG. 4, a positive potential application step (T1) that does not generate an electrochemical product, an amplitude potential application step (T3) in a negative potential region that does not generate an electrochemical product, and The positive potential application step (T6) for generating the electrochemical product is repeated alternately. The applied potential and the application period in each step can be appropriately determined according to circumstances, and the order and frequency are also arbitrary. The amplitude and change rate of the potential in the amplitude potential application step (T3) in the negative potential region where no electrochemical product is generated should be set within a range in which the controller 1 can output, although it depends on the responsiveness of the system. Can do. As in FIG. 3, for example, a positive potential applying step (T1) that does not generate an electrochemical product and an amplitude potential applying step (T3) in a negative potential region that does not generate an electrochemical product are alternately repeated a certain number of times. Then, it is also possible to create a pattern in which a positive potential applying step (T6) for generating an electrochemical product is applied.
[0025]
In the potential application pattern shown in the timing chart of FIG. 5, a positive potential application step (T1) that does not generate an electrochemical product, a negative potential application step (T2) that does not generate an electrochemical product, and an electrochemical product The negative potential applying step (T4) to be generated and the positive potential applying step (T6) to generate the electrochemical product are alternately repeated. The applied potential and the application period in each step can be appropriately determined according to circumstances, and the order and frequency are also arbitrary. For example, a positive potential application step (T1) that does not generate an electrochemical product and a negative potential application step (T2) that does not generate an electrochemical product are alternately repeated a certain number of times, and then an electrochemical product is generated. A pattern of applying a negative potential applying step (T4) and a positive potential applying step (T6) for generating an electrochemical product can be created.
In the potential application pattern shown in the timing chart of FIG. 6, a positive potential application step (T1) that does not generate an electrochemical product, a negative potential region that generates an electrochemical product, and / or an amplitude in a negative potential region that does not generate an electrochemical product. The potential application step (T5) and the positive potential application step (T6) for generating an electrochemical product are alternately repeated. The applied potential and the application period in each step can be appropriately determined according to circumstances, and the order and frequency are also arbitrary. The amplitude and change rate of the potential in the amplitude potential application step (T5) in the negative potential region where the electrochemical product is generated / not generated are set in a range that can be output by the control unit 1 depending on the response of the system. can do. For example, a positive potential application step (T1) that does not generate an electrochemical product and an amplitude potential application step (T5) in a negative potential region that does or does not generate an electrochemical product are repeated a certain number of times, and thereafter A pattern of applying a positive potential applying step (T6) for generating an electrochemical product can be created.
[0026]
<Preparation of conductive substrate>
The preparation procedure of the conductive materials 1 to 24 used in the examples is shown below.
Conductive substrate 1
A titanium substrate (equivalent to JIS type 2, t1 × w100 × L100 mm) is degreased with trichlene and washed, and then the surface layer is dissolved and washed in a 12% by weight hydrogen fluoride aqueous solution for 5 minutes to make the surface oxide film uniform, and then 70 Immerse in a weight% sulfuric acid aqueous solution at 120 ° C. for 1 minute and a half, homogenize the oxide film and form a TiHx film, and then after quenching, rinse in an argon gas stream and then rinsed rapidly in a 1% by weight ammonium fluoride aqueous solution. The TiHx film was soaked for 2 minutes in order to achieve uniform and stable growth, and was lifted and washed with water.
After water washing, dinitrodiaminoplatinum containing 5 g / L of platinum (Pt (NH_Three)₂(NO₂)₂) In a sulfuric acid aqueous solution and adjusted to a pH of about 2 at 50 ° C., 2 A / dm.²Was plated for about 20 minutes to form a 2 micron platinum plating layer. In order to protect the TiHx formation film in the plating process, nitrogen gas is aerated in the plating bath and stirred by gas-liquid stirring to remove dissolved oxygen and prevent the oxygen generated at the anode from contacting the titanium substrate. I tried to do it.
The platinum-plated titanium substrate thus obtained was heat-treated at 250 ° C. for 2 hours in a vacuum to decompose and remove the TiHx film.
Next, heating was performed at 380 ° C. for 1 hour in the atmosphere, and finally, the substrate was air-cooled to obtain a conductive substrate 1.
[0027]
Conductive substrate 2
A titanium substrate (corresponding to JIS type 2, t1 × w100 × L100 mm) was washed with alcohol, treated in an 8 wt% HF 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. Insert 24g of mixed powder into each carbon die having 10 holes with a diameter of 10mm, fix both ends with carbon punches, and discharge plasma sintering machine (DR.SINTER) manufactured by Sumitomo Coal Mining Co., Ltd. Installed at a predetermined position inside, about 350 kgf / cm²The sintering was performed under the conditions of a pulse application voltage of 4 V, a pulse application current of 3500 A, a sintering temperature of 800 ° C., and a sintering time of 5 minutes. Thereafter, surface polishing was performed to obtain a 65 wt% 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 an elemental analysis of the cross section of the titanium base material subjected to electric discharge machining was performed with EPMA (electroprobe micro analyzer), an alloy of titanium and palladium was confirmed. Moreover, when the component analysis by the comparative measurement with a discharge electrode was performed for the surface of electric discharge machining using the fluorescent X-ray analyzer, it was confirmed that the discharge electrode component was coat | covered. 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 / l of iridium (Ir) and 50.0 g / l of tantalum (Ta) (molar mixing ratio: 8Ir-92Ta) is prepared. Prepare 1cm with micropipette²After weighing 3.0 μl per unit and applying it on the titanium and alloy layer of the titanium substrate on which the palladium alloy layer was formed as described above, it was vacuum-dried at room temperature for 30 minutes, and further in the atmosphere of 500 ° C. Baked 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 iridium (Ir) 50.0 g / l and tantalum (Ta) 20.2 g / l (molar mixing ratio: 70 Ir-30Ta). ) Was prepared, and then the same process as described above was repeated 8 times using this coating liquid to obtain a conductive substrate 2.
[0028]
Conductive substrate 3
A titanium substrate (corresponding to JIS type 2, t1 × w100 × L100 mm) was degreased and washed with trichlene and then treated with a 10 wt% oxalic acid aqueous solution at 90 ° C. for 20 minutes. Subsequently, the titanium substrate was taken out from the oxalic acid aqueous solution, sprayed with cold water in a nitrogen atmosphere, rapidly cooled, and then dried under reduced pressure at room temperature.
Next, after chloroplatinic acid was dissolved in butanol to prepare a coating solution containing a platinum concentration of 50 g / l, the solution was applied onto the titanium substrate obtained above with a brush, dried at room temperature under reduced pressure, and further subjected to reduced pressure. Baked at 450 ° C. for 10 minutes. By repeating the coating-drying-firing process 30 times, the platinum coating amount is 1 cm.²About 1.6 mg of platinum coating layer was formed per unit.
Subsequently, an acidic aqueous solution of rhodium nitrate adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l was mixed with ethanol to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). 1cm of the coating solution with a micropipette²2.7 μl per unit was weighed, applied to the substrate, dried under reduced pressure at room temperature for 30 minutes, and further baked in air at 600 ° C. for 10 minutes. This coating-drying-firing process is repeated 5 times, and the platinum coating layer is 1 cm in terms of rhodium.²0.4 mg of rhodium oxide coating layer was formed per unit. Further, an acidic aqueous solution of palladium nitrate adjusted to a palladium concentration of 100 g / l (metal conversion) and a nitric acid concentration of 445 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). Using this coating solution, the same coating-drying-firing process as described above was repeated 11 times, and 1 cm in terms of palladium on the rhodium oxide layer.²A conductive oxide substrate 3 was formed by forming 0.8 mg of a palladium oxide layer per unit.
[0029]
Conductive substrate 4
Titanium substrate (equivalent to JIS type 2, t1 × w100 × L100mm) is degreased and washed with trichlorethylene, then treated in an 8 wt% hydrogen fluoride aqueous solution at 20 ° C for 2 minutes, then in a 60 wt% sulfuric acid aqueous solution at 120 ° C for 3 minutes Processed. Next, the titanium substrate was taken out of the sulfuric acid aqueous solution, and cooled rapidly by spraying cold water in a nitrogen atmosphere. Further, it was immersed in a 0.3 wt% hydrogen fluoride aqueous solution at 20 ° C. for 2 minutes and then washed with water.
After washing with water, dinitrodiaminoplatinum (Pt (NH_Three)₂(NO₂)₂) In a platinum solution with a platinum content of 5 g / l, a pH of about 2, and a temperature of 50 ° C.²Plating for about 6 minutes at an apparent density of 16 g / cm^ThreeThe electrodeposition amount is 1.7 mg / cm²A porous platinum coating layer was formed on a titanium substrate. Thus, the titanium base material provided with the porous platinum coating layer was heat-treated in the atmosphere at 400 ° C. for 1 hour.
Next, dinitrodiaminoplatinum (Pt (NH) adjusted to a platinum concentration of 50 g / l._Three)₂(NO₂)₂The aqueous nitric acid solution was heated to 80 ° C. and concentrated to a platinum concentration of about 300 g / l and then dissolved in butanol to prepare solution-1 containing a platinum concentration of 100 g / l, and further adjusted to an iridium concentration of 42 g / l. A butanol chloride iridate solution (solution-2) was prepared, and equal amounts of both solutions were mixed to prepare a solution having a platinum to iridium molar ratio of 7: 3.
This solution was weighed by 2.5 μl with a micropipette, allowed to penetrate the porous platinum coating layer, dried at room temperature for 30 minutes, and further baked in air at 550 ° C. for 10 minutes. This infiltration-drying-firing process is repeated three times, and platinum and iridium oxide are 0.5 mg / cm each on the porous platinum coating layer.²And 0.21 mg / cm²An iridium oxide-platinum composite made of (metal conversion) was carried to form a conductive substrate 4.
[0030]
Conductive substrate 5
Titanium substrate (equivalent to JIS type 2, t1 × w100 × L100mm) is degreased and washed with trichlorethylene, then treated in an 8 wt% hydrogen fluoride aqueous solution at 20 ° C for 2 minutes, and then in a 60 wt% sulfuric acid aqueous solution at 120 ° C for 3 minutes. Processed. Next, the titanium substrate was taken out of the sulfuric acid aqueous solution, and cooled rapidly by spraying cold water in a nitrogen atmosphere. Further, it was immersed in a 0.3 wt% hydrogen fluoride aqueous solution at 20 ° C. for 2 minutes and then washed with water.
After washing with water, dinitrodiaminoplatinum (Pt (NH_Three)₂(NO₂)₂) In a platinum solution with a platinum content of 5 g / l, a pH of about 2, and a temperature of 50 ° C.²Plating for about 6 minutes at an apparent density of 16 g / cm^ThreeThe electrodeposition amount is 1.7 mg / cm²A porous platinum coating layer was formed on a titanium substrate.
Thus, the titanium base material provided with the porous platinum coating layer was heat-treated in the atmosphere at 400 ° C. for 1 hour.
Next, a rhodium nitrate aqueous solution adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). 1 cm of this solution with a micropipette²2.7 μl per unit was weighed, applied to the porous platinum coating layer, dried at room temperature for 30 minutes, and further baked in the atmosphere at 600 ° C. for 10 minutes. This coating-drying-firing process is repeated 5 times, and the porous platinum coating layer is 1 cm in terms of rhodium.²A rhodium oxide layer consisting of 0.4 mg per unit was formed.
Then, a palladium nitrate aqueous solution adjusted to a palladium concentration of 100 g / l (metal conversion) and a nitric acid concentration of 445 g / l and ethanol were mixed to prepare a solution containing a palladium concentration of 25 g / l (metal conversion), and further a rhodium concentration of 50 g / l. l (metal conversion) and a rhodium nitrate aqueous solution adjusted to a nitric acid concentration of 95 g / l were added and mixed to prepare a coating solution containing palladium nitrate and rhodium nitrate with a palladium to rhodium molar ratio (metal conversion) of 20: 1. To do. Using this coating solution, the coating-drying-firing process was repeated 8 times in the same manner as described above, and 1 cm in terms of metal²The conductive base material on which an oxide coating layer containing 0.6 mg of palladium oxide and 0.03 mg of rhodium oxide was formed was designated 5.
[0031]
Conductive substrate 6
Titanium substrate (equivalent to JIS type 2, t1 × w100 × L100mm) is degreased and washed with trichlorethylene, then treated in an 8 wt% hydrogen fluoride aqueous solution at 20 ° C for 2 minutes, and then in a 60 wt% sulfuric acid aqueous solution at 120 ° C for 3 minutes. Processed. Next, the titanium substrate was taken out of the sulfuric acid aqueous solution, and cooled rapidly by spraying cold water in a nitrogen atmosphere. Further, it was immersed in a 0.3 wt% hydrogen fluoride aqueous solution at 20 ° C. for 2 minutes and then washed with water.
After washing with water, dinitrodiaminoplatinum (Pt (NH_Three)₂(NO₂)₂Is dissolved in a sulfuric acid aqueous solution and 15 mA / cm in a platinum plating solution in which the platinum content is adjusted to 5 g / l, pH is about 2, and the temperature is 50 ° C.²Was plated for about 50 seconds to disperse and deposit platinum. Dispersion coverage is 1 g / m^ThreeMet. At this time, the platinum coverage on the titanium substrate was about 40%.
Thus, the titanium substrate on which platinum was dispersedly coated was heat-treated in the atmosphere at 40 ° C. for 1 hour.
Next, a butanol solution of chloroiridic acid and an ethanol solution of tantalum chloride are mixed to prepare a coating solution containing iridium (Ir) 13.0 g / l and tantalum (Ta) 50.0 g / l (metal conversion), 1 cm with a micropipette²2.7 μl per unit was weighed and applied onto a titanium substrate coated with platinum prepared as described above, and then vacuum-dried at room temperature for 30 minutes and further baked in air at 500 ° C. for 10 minutes. This process was repeated twice.
Next, in order to obtain an outer layer, a solution containing iridium (Ir) 50.0 g / l and tantalum (Ta) 20.0 g / l (metal conversion) mixed with a butanol solution of chloroiridate and an ethanol solution of tantalum chloride. After preparing the liquid, the same process as described above was repeated 8 times using this coating liquid to obtain a conductive substrate 6.
[0032]
Conductive substrate 7
A titanium plate (corresponding to JIS 2 type, t1 × w100 × L100 mm) was polished with sandpaper to remove surface stains, further immersed in an organic solvent and washed with an ultrasonic cleaner. 260 g / l cobalt nitrate hexahydrate (Co (NO_Three )₂ ・ 6H₂O) An aqueous solution was applied to the surface. After coating, the film was dried for 20 to 30 minutes, and then subjected to heat activation treatment with a gas burner. This was designated as conductive substrate 7.
[0033]
Conductive substrate 8
Titanium was sprayed under the following conditions using a low-temperature spraying device (PC250iDEX, manufactured by Arctechno Co., Ltd.). As the titanium, a pure titanium wire having a diameter of 1.3 mm was used. High frequency of 40kHz, voltage is 14V, feed speed of titanium wire is 5.2m / min, air cooled to 11 ° C is 8kg / cm²A 200 μm titanium sprayed coating was coated on a cement plate (50 × 300 × 300 mm) whose surface was blasted with a pressure of The titanium spray coating had a pale yellow color tone.
Next, 260 g / l cobalt nitrate hexahydrate (Co (NO_Three )₂ ・ 6H₂O) aqueous solution and 18 g / l iridium chloride (IrCl_Four・ H₂An aqueous solution to which O) was added was applied. After coating, the film was dried for 20 to 30 minutes, and then the film was heated and dried with a gas flame to obtain a conductive substrate 8.
[0034]
Conductive substrate 9
A titanium plate (corresponding to JIS 2 type, t1 × w100 × L100 mm) was polished with sandpaper to remove surface stains, further immersed in an organic solvent and washed with an ultrasonic cleaner. 260 g / l manganese nitrate hexahydrate (Mn (NO_Three )₂ ・ 6H₂O) The solution was applied to the surface. After coating, the film was dried for 20 to 30 minutes, and then subjected to heat activation treatment with a gas burner. This was designated as conductive substrate 9.
[0035]
Conductive substrate 10
A titanium plate (corresponding to JIS type 2, t1 × w100 × L100 mm) was immersed in an organic solvent and washed with an ultrasonic cleaner. Next, a titanium plate is placed in the physical vapor deposition apparatus, evacuated to 0.13 mPa, etched for 5 minutes in argon plasma, and injected with methane gas until the degree of vacuum drops to 1.3 Pa. A zirconium nitride film having a thickness of 1 μm was formed by a ting method.
Next, a rhodium nitrate aqueous solution adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). 1 cm of this solution with a micropipette²2.7 μl per unit was weighed, applied to the zirconium nitride layer, dried at room temperature for 30 minutes, and further baked in the atmosphere at 600 ° C. for 10 minutes. This coating-drying-firing process is repeated 5 times, and the zirconium nitride layer is 1 cm in terms of rhodium.²A rhodium oxide layer consisting of 0.4 mg per unit was formed as the conductive substrate 10.
[0036]
Conductive substrate 11
A titanium plate (corresponding to JIS type 2, t1 × w100 × L100 mm) was immersed in an organic solvent and washed with an ultrasonic cleaner. Next, a titanium plate was placed in the physical vapor deposition apparatus and evacuated to 0.13 mPa. The titanium plate was etched in argon plasma for 5 minutes, and nitrogen gas was injected until the degree of vacuum decreased to 1.3 Pa. A nitride compound film made of titanium nitride and zirconium nitride was formed to 1 μm by an ion plating method.
Next, a rhodium nitrate aqueous solution adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). 1 cm of this solution with a micropipette²2.7 μl per unit was weighed and applied to a nitride compound film layer composed of titanium nitride and zirconium nitride, then dried at room temperature for 30 minutes, and further baked in air at 600 ° C. for 10 minutes. This coating-drying-firing process is repeated 5 times, and a nitride compound coating layer composed of titanium nitride and zirconium nitride is applied to 1 cm in terms of rhodium.²A rhodium oxide layer consisting of 0.4 mg per unit was formed as a conductive substrate 11.
[0037]
Conductive substrate 12
A tantalum plate (30 × 50 × 1 mm) was immersed in an organic solvent and washed with an ultrasonic cleaner. The cleaned tantalum plate was placed in a muffle furnace, nitrogen gas was introduced into the muffle furnace at 1 L / min, and treated at 900 ° C. for 1 hour to form a tantalum nitride film on the tantalum plate.
Next, a rhodium nitrate aqueous solution adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). 1 cm of this solution with a micropipette²2.7 μL per unit was weighed and applied to the tantalum nitride layer, then dried at room temperature for 30 minutes, and further baked in air at 600 ° C. for 10 minutes. This coating-drying-firing process is repeated 5 times, and the tantalum nitride layer is 1 cm in terms of rhodium.²A rhodium oxide layer consisting of 0.4 mg per unit was formed as a conductive substrate 12.
[0038]
Conductive substrate 13
Titanium was sprayed under the following conditions using a low-temperature spraying device (PC250iDEX, manufactured by Arctechno Co., Ltd.). As the titanium, a pure titanium wire having a diameter of 1.3 mm was used. High frequency of 40kHz, voltage is 14V, feed speed of titanium wire is 5.2m / min, air cooled to 11 ° C is 8kg / cm²A 200 μm titanium sprayed coating was coated on a cement plate (50 × 300 × 300 mm) whose surface was blasted with a pressure of The titanium spray coating had a pale yellow color tone.
Next, 260 g / l manganese nitrate hexahydrate (Mn (NO_Three )₂ ・ 6H₂ O) aqueous solution and 18 g / l iridium chloride (IrCl_Four ・ H₂An aqueous solution to which O) was added was applied. After coating, the film was dried for 20 to 30 minutes, and then the film was heated and dried with a gas flame to obtain a conductive substrate 13.
[0039]
Conductive substrate 14
Titanium was sprayed under the following conditions using a low-temperature spraying device (PC250iDEX, manufactured by Arctechno Co., Ltd.). As the titanium, a pure titanium wire having a diameter of 1.3 mm was used. High frequency of 40kHz, voltage is 14V, feed speed of titanium wire is 5.2m / min, air cooled to 11 ° C is 8kg / cm²A 200 μm titanium sprayed coating was coated on a cement plate (50 × 300 × 300 mm) whose surface was blasted with a pressure of The titanium spray coating had a pale yellow color tone.
Next, the titanium spray-coated cement board was degreased and washed with trichlorethylene, treated in an aqueous 8 wt% hydrogen fluoride solution at 20 ° C. for 2 minutes, and then treated in an aqueous 60 wt% sulfuric acid solution at 120 ° C. for 3 minutes. Next, the titanium sprayed coating-coated cement plate was taken out from the sulfuric acid aqueous solution and rapidly cooled by spraying cold water in a nitrogen atmosphere. Further, it was immersed in a 0.3 wt% hydrogen fluoride aqueous solution at 20 ° C. for 2 minutes and then washed with water.
After washing with water, dinitrodiaminoplatinum (Pt (NH_Three)₂(NO₂)₂) In a platinum solution with a platinum content of 5 g / l, a pH of about 2, and a temperature of 50 ° C.²Plating for about 6 minutes at an apparent density of 16 g / cm^ThreeThe electrodeposition amount is 1.7 mg / cm²The porous platinum coating layer was formed on a titanium spray coating coated cement board.
The titanium spray-coated cement board thus provided with the porous platinum coating layer was heat-treated in the atmosphere at 400 ° C. for 1 hour.
Next, a rhodium nitrate aqueous solution adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). 1 cm of this solution with a micropipette²2.7 μl per unit was weighed, applied to the porous platinum coating layer, dried at room temperature for 30 minutes, and further baked in air at 600 ° C. for 10 minutes. This coating-drying-firing process is repeated 5 times, and the porous platinum coating layer is 1 cm in terms of rhodium.²A rhodium oxide layer consisting of 0.4 mg per unit was formed.
Then, a palladium nitrate aqueous solution adjusted to a palladium concentration of 100 g / l (metal conversion) and a nitric acid concentration of 445 g / l and ethanol were mixed to prepare a solution containing a palladium concentration of 25 g / l (metal conversion), and further a rhodium concentration of 50 g / l. l (metal conversion) and a rhodium nitrate aqueous solution adjusted to a nitric acid concentration of 95 g / l were added and mixed to prepare a coating solution containing palladium nitrate and rhodium nitrate with a palladium to rhodium molar ratio (metal conversion) of 20: 1. To do. Using this coating solution, the coating-drying-firing process was repeated 8 times in the same manner as described above, and 1 cm in terms of metal²An oxide coating layer containing 0.6 mg of palladium oxide and 0.03 mg of rhodium oxide was formed to form a conductive substrate 14.
[0040]
Conductive substrate 15
What added 5 weight% of isocyanate hardening agent (Nippon Polyurethane Co., Ltd. coronate L) to polyester adhesive (the product made by Toa Gosei Co., Ltd., PES360SK) on the surface of a stainless steel plate (30x50x1mm). After applying by a spray method, it was dried at 100 ° C. for 5 minutes.
Next, a 50 μm thick polyester resin film (Lintec Co., Ltd.) was laminated as an insulating resin film by thermocompression bonding. Next, the polyester-based adhesive used for bonding the polyester resin film onto the stainless steel substrate was coated on the polyester resin film under the same conditions and dried. Next, it laminated | stacked on the polyester resin film by heat-pressing the electroconductive sheet which consists of 0.1 mm titanium foil. The stainless steel side of this titanium foil coated stainless steel plate is protected with resist ink, degreased with trichlene, washed, then the surface layer is dissolved and washed in a 12% hydrogen fluoride aqueous solution for 5 minutes, and the surface oxide film is made uniform. Next, it was immersed in a 70% by weight sulfuric acid aqueous solution at 120 ° C. for 1 minute and a half to homogenize the oxide film and form a TiHx film, and then washed with quenching water in an argon gas stream and then washed with 1% by weight ammonium fluoride. The TiHx film was immersed in an aqueous solution for 2 minutes to achieve uniform and stable growth, and was lifted and washed with water.
After washing with water, dinitrodiaminoplatinum containing 5 g / l of platinum (Pt (NH_Three)₂(NO₂)₂) Dissolved in sulfuric acid and adjusted to a pH of about 2 at 50 ° C., 2 A / dm²After plating for about 20 minutes, a 2 micron platinum plating layer was obtained. In the plating process, in order to protect the TiHx formation film, nitrogen gas is aerated in the plating bath, gas-liquid stirring is performed to remove dissolved oxygen, and contact between the oxygen generated at the anode and the titanium substrate is prevented by the diaphragm. I did it.
The thus obtained platinum-plated titanium substrate was heat-treated at 250 ° C. for 2 hours in a vacuum to decompose and remove the TiHx film.
Further, an acidic aqueous solution of rhodium nitrate adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l was mixed with ethanol to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). 1cm of the coating solution with a micropipette²2.7 μl per unit was weighed, applied to the substrate, dried under reduced pressure at room temperature for 30 minutes, and then baked in the atmosphere for 10 minutes with a burner so that the outermost surface was 600 ° C. This coating-drying-firing process is repeated 5 times, and the platinum coating layer is 1 cm in terms of rhodium.²0.4 mg of rhodium oxide coating layer was formed per unit. Further, an acidic aqueous solution of palladium nitrate adjusted to a palladium concentration of 100 g / l (metal conversion) and a nitric acid concentration of 445 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). Using this coating solution, the same coating-drying-firing process as described above was repeated 11 times, and 1 cm in terms of palladium on the rhodium oxide layer.²A 0.8 mg palladium oxide layer was formed per conductive substrate 15.
[0041]
Conductive substrate 16
The surface of the stainless steel plate (SUS316, 30 × 50 × 5 mm) was roughened with emery paper (No. 100). Next, 5 parts by weight of an isocyanate curing agent (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L) and a solvent (toluene and methyl ethyl ketone are 8: 2) to a polyester adhesive (manufactured by Toa Gosei Co., Ltd., PES · 360S30). 100 parts by weight) was added and mixed with sufficient stirring. The adhesive was applied to the roughened stainless steel surface by a spray method, and then dried at 80 ° C. for 10 minutes. Next, a cloth woven from glass fibers (manufactured by Unitika Glass Fiber Co., Ltd., H201M104F) is placed on a stainless steel plate coated with an adhesive, and 200 ° C., 10 kg / cm.²And pressure-bonded for 2 minutes. Next, titanium was sprayed under the following conditions using a low-temperature spraying device (Arc Techno Co., Ltd., PC250iDEX). In addition, the titanium used the pure titanium wire with a diameter of 1.3 mm. The voltage is 14V, the feed speed of titanium wire is 5.2m / min, and the air pressure is 8kg / cm²A 200 μm titanium nitride sprayed coating was formed by spraying titanium on a stainless steel plate on which glass fiber cloths were laminated.
Next, the stainless steel side of the titanium spray coating coated stainless steel plate is protected with a resist ink, degreased and washed with trichlorethylene, treated in an 8 wt% hydrogen fluoride aqueous solution at 20 ° C. for 2 minutes, and then 60 wt% sulfuric acid at 120 ° C. Treated in aqueous solution for 3 minutes. Subsequently, the titanium sprayed coating-coated stainless steel plate was taken out from the sulfuric acid aqueous solution and rapidly cooled by spraying cold water in a nitrogen atmosphere. Further, it was immersed in a 0.3 wt% hydrogen fluoride aqueous solution at 20 ° C. for 2 minutes and then washed with water.
After washing with water, dinitrodiaminoplatinum (Pt (NH_Three)₂(NO₂)₂) In a sulfuric acid solution and 30 mA / cm in a platinum plating solution with a platinum content of 5 g / l, a pH of about 2 and a temperature adjusted to 50 ° C.²Plating for about 6 minutes at an apparent density of 16 g / cm^ThreeThe electrodeposition amount is 1.7 mg / cm²The porous platinum coating layer was formed on a titanium spray coating coated stainless steel plate.
The titanium spray-coated stainless steel plate provided with the porous platinum coating layer in this way was heat-treated in the atmosphere at 400 ° C. for 1 hour.
Next, a rhodium nitrate aqueous solution adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). 1 cm of this solution with a micropipette²2.7 μl per unit was weighed, applied to the porous platinum coating layer, dried at room temperature for 30 minutes, and further baked in the atmosphere at 600 ° C. for 10 minutes. This coating-drying-firing process is repeated 5 times, and the porous platinum coating layer is 1 cm in terms of rhodium.²A rhodium oxide layer consisting of 0.4 mg per unit was formed.
Then, a palladium nitrate aqueous solution adjusted to a palladium concentration of 100 g / l (metal conversion) and a nitric acid concentration of 445 g / l and ethanol were mixed to prepare a solution containing a palladium concentration of 25 g / l (metal conversion), and further a rhodium concentration of 50 g / l. l (metal conversion) and a rhodium nitrate aqueous solution adjusted to a nitric acid concentration of 95 g / l were added and mixed to prepare a coating solution containing palladium nitrate and rhodium nitrate with a palladium to rhodium molar ratio (metal conversion) of 20: 1. To do. Using this coating solution, the coating-drying-firing process was repeated 8 times in the same manner as described above, and 1 cm in terms of metal²An oxide coating layer containing 0.6 mg of palladium oxide and 0.03 mg of rhodium oxide was formed to form a conductive substrate 16.
[0042]
Conductive substrate 17
A stainless steel plate (30 × 50 × 1 mm) was immersed in an organic solvent and washed with an ultrasonic cleaner. Next, a titanium plate was placed in the physical vapor deposition apparatus and evacuated to 0.13 mPa. The stainless steel plate was etched in argon plasma for 5 minutes to form a titanium layer having a thickness of 2 μm. Thereafter, nitrogen gas was injected to 1.3 Pa until the degree of vacuum decreased, and a titanium nitride film was formed to 1 μm by an ion plating method.
Next, a rhodium nitrate aqueous solution adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). 1 cm of this solution with a micropipette²2.7 μL per unit was weighed, applied to the titanium nitride layer, dried at room temperature for 30 minutes, and further baked in air at 600 ° C. for 10 minutes. This coating-drying-firing process is repeated 5 times, and the titanium nitride layer is 1 cm in terms of rhodium.²A rhodium oxide layer consisting of 0.4 mg per unit was formed as a conductive substrate 17.
[0043]
Conductive substrate 18
A glass fiber reinforced plastic (FRP) plate (30 × 50 × 5 mm) was immersed in alcohol and washed with an ultrasonic cleaner. Next, a glass fiber reinforced plastic (FRP) plate was placed in the physical vapor deposition apparatus and evacuated to 0.13 mPa. The glass fiber reinforced plastic (FRP) plate was etched in argon plasma for 5 minutes, and then argon gas was injected to 1.3 Pa until the degree of vacuum was lowered to form a titanium film of 50 μm by sputtering.
Next, the titanium-coated glass fiber reinforced plastic (FRP) plate is degreased with trichlene and washed, and then the surface layer is dissolved and washed in a 12 wt% hydrogen fluoride aqueous solution for 5 minutes to make the surface oxide film uniform, and then 70 Immerse in a weight% sulfuric acid aqueous solution at 120 ° C. for 1 minute and a half, homogenize the oxide film and form a TiHx film, and then after quenching, rinse in an argon gas stream and then rinsed rapidly in a 1% by weight ammonium fluoride aqueous solution. The TiHx film was soaked for 2 minutes in order to achieve uniform and stable growth, and the TiHx film was lifted and washed with water.
After washing with water, dinitrodiaminoplatinum containing 5 g / l of platinum (Pt (NH_Three)₂(NO₂)₂) Dissolved in sulfuric acid and adjusted to a pH of about 2 at a temperature of 50 ° C. and a current density of 2 A / dm.²After plating for about 20 minutes, a 2 micron platinum plating layer was obtained. In order to protect the TiHx formation film in the plating process, nitrogen gas is aerated in the plating bath, gas-liquid stirring is performed to remove dissolved oxygen, and oxygen generated at the anode is prevented from coming into contact with the titanium substrate. I made it.
The thus obtained platinum-plated titanium substrate was heat-treated at 250 ° C. for 2 hours in a vacuum to decompose and remove the TiHx film.
Next, an acidic aqueous solution of rhodium nitrate adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). . 1cm of the coating solution with a micropipette²2.7 μl per unit was weighed, applied to the substrate, dried under reduced pressure at room temperature for 30 minutes, and further baked in air for 10 minutes so that the outermost surface reached 600 ° C. with a burner. This coating-drying-firing process is repeated 5 times, and the platinum coating layer is 1 cm in terms of rhodium.²0.4 mg of rhodium oxide coating layer was formed per unit. Further, an acidic aqueous solution of palladium nitrate adjusted to a palladium concentration of 100 g / l (metal conversion) and a nitric acid concentration of 445 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). Using this coating solution, the same coating-drying-firing process as described above was repeated 11 times, and 1 cm in terms of palladium on the rhodium oxide layer.²A 0.8 mg palladium oxide layer was formed per conductive substrate 18.
[0044]
Conductive substrate 19
An aluminum plate (30 × 50 × 1 mm) was etched for 30 seconds in a 5% by weight sodium hydroxide aqueous solution at a temperature of 50 ° C. and then immersed in a 30% by weight nitric acid aqueous solution for 1 minute. Thereafter, 1.5 A / dm in a 15 wt% aqueous sulfuric acid solution.²The porous oxide film having a thickness of 24 μm was formed by anodizing at a current density of 60 minutes. Next, an aluminum plate with a porous oxide film formed thereon is immersed as an anode in an anionic electrodeposition coating (manufactured by Honey Kasei Co., Ltd.), a voltage of 180 V is applied for 3 minutes, followed by washing with water at 180 ° C. for 30 minutes. An insulating resin layer was formed on the porous oxide film by heating and drying. Next, an aluminum plate on which an insulating resin layer was formed was placed in a physical vapor deposition apparatus, and vacuuming was performed to 1.3 mPa. Thereafter, etching was performed in argon plasma for 5 minutes to form a titanium layer having a thickness of 2 μm, and then nitrogen gas was injected to 1.3 Pa until the degree of vacuum was reduced to form a titanium nitride film having a thickness of 1 μm by an ion plating method.
Next, a rhodium nitrate aqueous solution adjusted to a rhodium concentration of 50 g / l (metal conversion) and a nitric acid concentration of 95 g / l and ethanol were mixed to prepare a coating solution containing a rhodium concentration of 25 g / l (metal conversion). 1 cm of this solution with a micropipette²2.7 μl per unit was weighed, applied to the titanium nitride layer, dried at room temperature for 30 minutes, and further baked in the atmosphere at 600 ° C. for 10 minutes. This coating-drying-firing process is repeated 5 times, and the titanium nitride layer is 1 cm in terms of rhodium.²A rhodium oxide layer consisting of 0.4 mg per unit was formed as a conductive substrate 19.
[0045]
Conductive substrate 20
Titanium was sprayed under the following conditions using a low-temperature spraying device (PC250iDEX, manufactured by Arctechno Co., Ltd.). As the titanium, a pure titanium wire having a diameter of 1.3 mm was used. High frequency of 40kHz, voltage is 14V, feed speed of titanium wire is 5.2m / min, air cooled to 11 ° C is 8kg / cm²A 200 μm titanium sprayed coating was coated on a cement plate (50 × 300 × 300 mm) whose surface was blasted with a pressure of The titanium spray coating had a pale yellow color tone. This was designated as conductive substrate 20.
[0046]
Conductive substrate 21
The surface of a glass fiber reinforced plastic (FRP) plate (30 × 50 × 5 mm) was roughened with emery paper (No. 100). Next, 5 parts by weight of an isocyanate-based curing agent (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L) to a polyester-based adhesive (manufactured by Toa Gosei Co., Ltd., PES360S30) and a solvent (toluene and methyl ethyl ketone in a capacity of 8: 2) 100 parts by weight of the mixture) was added and sufficiently stirred and mixed. The adhesive was applied to the surface of the roughened glass fiber reinforced plastic (FRP) plate by a spray method, and then dried at 80 ° C. for 10 minutes. Next, a cloth woven with glass fiber (manufactured by Unitika Glass Fiber Co., Ltd., H201M104F) is placed on a glass fiber reinforced plastic (FRP) plate coated with an adhesive, and the temperature is 200 ° C., 10 kg / cm.²And pressure-bonded for 2 minutes. Next, titanium was sprayed under the following conditions using a low-temperature spraying device (Arc Techno Co., Ltd., PC250iDEX). In addition, the titanium used the pure titanium wire with a diameter of 1.3 mm. Voltage is 14V, Titanium wire feed speed is 5.2m / min, Air pressure is 8kg / cm²A 200 μm titanium nitride spray coating was formed by spraying titanium on a glass fiber reinforced plastic (FRP) plate on which glass fiber cloths were laminated. This was used as the conductive substrate 21.
[0047]
Conductive substrate 22
A titanium substrate (corresponding to JIS 2 types, t1 × w100 × L100 mm) was degreased and washed with trichloroethylene, and this was used as the conductive base material 22.
[0048]
Conductive substrate 23
A stainless steel plate (30 × 50 × 1 mm) was immersed in an organic solvent and washed with an ultrasonic cleaner. Next, a titanium plate was placed in the physical vapor deposition apparatus and evacuated to 0.13 mPa. The stainless steel plate was etched in argon plasma for 5 minutes to form a titanium layer having a thickness of 2 μm. Thereafter, nitrogen gas was injected to 1.3 Pa until the degree of vacuum decreased, and a titanium nitride film was formed to 1 μm by an ion plating method. This was used as the conductive substrate 23.
[0049]
Conductive substrate 24
An aluminum plate (30 × 50 × 1 mm) was etched in a 5 wt% sodium hydroxide aqueous solution at 50 ° C. for 30 seconds, and then immersed in a 30 wt% nitric acid aqueous solution for 1 minute. Thereafter, 1.5 A / dm in a 15 wt% aqueous sulfuric acid solution.²The porous oxide film having a thickness of 24 μm was formed by anodizing at a current density of 60 minutes. Next, an aluminum plate with a porous oxide film formed thereon is immersed as an anode in an anionic electrodeposition coating (manufactured by Honey Kasei Co., Ltd.), a voltage of 180 V is applied for 3 minutes, followed by washing with water at 180 ° C. for 30 minutes. An insulating resin layer was formed on the porous oxide film by heating and drying. Next, an aluminum plate on which an insulating resin layer was formed was placed in a physical vapor deposition apparatus, and vacuuming was performed to 1.3 mPa. Thereafter, etching was performed in argon plasma for 5 minutes to form a titanium layer having a thickness of 2 μm, and then nitrogen gas was injected to 1.3 Pa until the degree of vacuum was reduced to form a titanium nitride film having a thickness of 1 μm by an ion plating method. This was used as the conductive substrate 24.
[0050]
<Preparation of microorganism suspension>
After primary culture of marine-adherent bacterium Vibrio alginoliticus (ATCC 17749) at 30 ° C. in Marine broth (Marine broth) 2216 (manufactured by DIFCO Laboratories), 100 μl was collected and cultured in a 25 ml centrifuge tube (marine). Broth was aerobically cultured at 15 ° C. and 150 rpm for 2 hours. The cultured cells are collected by centrifugation, washed with sterilized seawater, suspended in sterilized seawater, counted with a hematite meter, and 1 × 10⁷A cell suspension having a concentration of cel 1 / ml was prepared.
[0051]
<Microbe adhesion to conductive substrate and potential application>
The conductive substrate was immersed in a suspension stirred at 200 rpm for 90 minutes at room temperature to allow the bacterial cells to adhere to the surface of the conductive substrate. It was immersed in sterilized seawater contained in the test tank 6, and various potentials were applied while stirring the sterilized seawater at a stirring speed of 200 rpm. As the potential application condition, each pattern shown in FIGS. Further, the potential of T1 was 0.9 V vs Ag / AgCl and applied for 60 minutes. The potential of T2 was −0.6 V vs Ag / AgCl and applied for 30 minutes. The potential of T3 was −0.3 V to −0.6 V vs Ag / AgCl, applied for 30 minutes, and the potential was amplified at intervals of 2 minutes. The potential of T4 was −1.4 V vs. Ag / AgCl and applied for 60 minutes. The potential of T5 was −0.3 V to −1.4 V vs. Ag / AgCl, applied for 60 minutes, and the potential was amplified at intervals of 2 minutes. The potential of T6 was applied at 1.6 V vs Ag / AgCl for 5 minutes.
[0052]
<Evaluation of sterilization of microorganisms and determination of effects of each process>
For the confirmation of the bactericidal effect, the removal of dead attached microorganisms, and the determination of the cleaning effect, 2 of Propidium Iodide (hereinafter abbreviated as PI) and 4,6-diamidino-2-phenylindole (hereinafter abbreviated as DAPI) This was performed by the double staining method. PI and DAPI are microorganisms that adhere to nucleic acid of microorganisms due to the difference in the permeability of microorganisms to the cell membrane. Those that show blue fluorescence are live cells, and those that show red fluorescence are dead cells. in use. Further, by comparing the abundance of the sterilized microorganisms emitting red fluorescence on the surface of the conductive substrate, the detachment of the scale and the organic matter and the cleaning function were determined.
Microorganism staining is performed by washing a conductive substrate to which a potential is applied with sterilized seawater, and adhering bacterial cells on the conductive substrate with 250 μg / ml aqueous solution of PI and 30 μl each of DAPI20 μg / ml aqueous solution (adjusted before staining). Drip. After that, bacteria that adsorbed to the conductive film before applying the potential were irradiated with ultraviolet excitation light, and under the observation of a fluorescence microscope, those showing blue fluorescence were viable cells and those showing red fluorescence were dead cells. The number of dead cells relative to the number of cells was evaluated.
In the determination, ○ indicates a sterilization rate of 80% or more, Δ indicates a sterilization rate of 20 to 80%, and X indicates less than 20%.
In the potential application patterns shown in FIGS. 2 to 6, the sterilizing effect of the microorganisms was determined after completing the T1 step.
The determinations of the detachment steps T2 and T3 are as follows: the attached organism amount after applying the potential is a decrease ratio from the T1 step after the sterilization determination. Shown as less than 30%.
The determination of the T4, T5, and T6 steps was determined based on the state of each pattern before the T4, T5, and T6 steps and the presence or absence of dead cells after each step.
In order to determine the superiority of the test results, various times were applied for the potential application time and the applied voltage. Therefore, it is desirable to give priority to the result of considering the test result with a completely low potential in a short time as a whole, and is not limited to this example.
Hereinafter, the effect is shown based on an Example about the electroconductive base materials 1-24 in each process of the electric potential application pattern shown to FIGS.
[0053]
Example 1
In Device Example 1, the conductive substrates 1 to 24 were used as the conductive substrate, and an experiment was performed using the potential application pattern shown in FIG. The results are shown in Table 1.
In the T1 step, 0.9VvsAg / AgCl was applied for 60 minutes to determine the bactericidal efficiency. The number of dead cells attached only in the T1 step and the presence or absence of dead cells regarded as organic matter attached after applying the T6 step to 1.6 V vs. Ag / AgCl for 5 minutes were analyzed for cleaning. The effect was judged.
[0054]
[Table 1]

[0055]
In the determination of the bactericidal effect, ◯ indicates a sterilization rate of 80% or more, Δ indicates a sterilization rate of 20 to 80%, and x indicates less than 20%. Moreover, what can confirm that the disinfection rate exceeded 80% even for a short time was described by (double-circle). It should be noted that this was not performed for all the substrates.
The degradation cleaning effect indicates the presence or absence of adherent dead cells, ◯ indicates a cleaning rate of 80% or more, Δ indicates a cleaning rate of 20 to 80%, and X indicates a cleaning rate of less than 20%. Moreover, the thing which confirmed that the washing | cleaning rate exceeded 80% even for a short time was described with (double-circle). It should be noted that this was not performed for all the substrates.
[0056]
Example 2
In the apparatus example 1, the said conductive base materials 1-24 were used as a conductive base material, and it experimented by the electric potential application pattern shown to FIG. The results are shown in Table 2.
Since the bactericidal effect showed substantially the same bactericidal efficiency as in Example 1, 0.9VvsAg / AgCl was applied for 30 minutes in the T1 process, and dead and live bacteria were mixed and adhered conductive groups. The material was adjusted. Thereafter, the T2 potential in the potential application pattern shown in FIG. 3 is −0.6 V vs Ag / AgCl, and applied for 30 minutes, and the potential of the potential application pattern T3 shown in FIG. 4 is −0.3 V to −0.6 V vs Ag / AgCl was applied for 30 minutes and the potential was oscillated at 2 minute intervals. Before and after the T2 step and T3 step at that time, the number of detached microorganisms was compared with the number of attached microorganisms, which is the sum of dead bacteria and viable bacteria, and the reduction ratio was determined to determine the detachment effect.
[0057]
[Table 2]

[0058]
As for the reduction rate, ◯ is shown as 70% or more, Δ is shown as 30 to 70%, and x is less than 30%. Moreover, the thing which confirmed that the reduction rate exceeded 80% even for a short time was described with (double-circle). In addition, the washing | cleaning effect could be confirmed with all the electroconductive base materials which implemented T6 process after that, and the washing | cleaning acceleration effect by the combination was expectable.
[0059]
Example 3
In the apparatus example 1, the said conductive base materials 1-24 were used as a conductive base material, and it experimented by the electric potential application pattern shown in FIG. The results are shown in Table 3.
Since the bactericidal effect showed substantially the same bactericidal efficiency as in Example 1, 0.9VvsAg / AgCl was applied for 30 minutes in the T1 process, and dead and live bacteria were mixed and adhered conductive groups. The material was adjusted. Thereafter, the T2 potential was -0.6 V vs Ag / AgCl and applied for 30 minutes. Next, the electric setting of T4 in the potential application pattern shown in FIG. 5 was set to -1.4 V vs Ag / AgCl for 60 minutes. Further, the potential setting of T5 in the potential application pattern shown in FIG. 6 was applied from -0.3 V to -1.4 V vs Ag / AgCl for 60 minutes, and the potential was amplified at intervals of 2 minutes. Before and after the T4 and T5 steps, the degradation and cleaning effect was determined by the presence or absence of dead cells regarded as attached organic matter.
[0060]
[Table 3]

[0061]
The degradation cleaning effect indicates the presence or absence of adherent dead cells, ◯ indicates a cleaning rate of 80% or more, Δ indicates a cleaning rate of 20 to 80%, and X indicates a cleaning rate of less than 20%. Moreover, the thing which confirmed that the washing | cleaning rate exceeded 80% even for a short time was described with (double-circle). It should be noted that this was not performed for all the substrates. Moreover, when T6 process was implemented after that, almost perfect washing | cleaning effect could be confirmed with all the electroconductive base materials in a short time, and the washing | cleaning acceleration effect by the combination was expectable.
[0062]
<Confirmation of product (chlorine, oxygen) generation>
About the electroconductive base materials 1,5,6,7,9,11,22, it immerses in 50 ml of seawater, 1.6Vvs. The chlorine concentration in seawater was measured when a potential of Ag / AgCl was applied. The chlorine concentration in seawater to which a potential was applied was measured using a residual chlorine electrode (97-70BN; manufactured by Orion Research). 10 ml of seawater after potential application was sampled, and 100 μl each of iodine reagent (manufactured by Orion Research) and acid reagent (manufactured by Orion Research) were added and stirred. After the solution was allowed to stand for 2 minutes, a multimeter (83 MULTITIMER; manufactured by FLUKE) was connected, the potential was measured with a residual chlorine electrode, and the chlorine concentration was determined using a calibration curve from the electrode potential difference from the standard sample. The chlorine measurement limit is 0.2 ppm. The standard sample was prepared by adding 100 μl each of residual chlorine standard solution (manufactured by Orion Research), iodine reagent, and acid reagent and stirring for 2 minutes, and then adding 9900 μl of distilled water and stirring again.
As a result, generation of chlorine was confirmed when noble metal oxide was present on the surface of the conductive substrate 1, 5, 6, 11. In addition, in the conductive base material, oxides such as 7, 9, and 22 and bulk metals, oxygen generation accompanying water decomposition was confirmed, indicating the existence of a radical generation process.
[0063]
<Verification of reactivation of conductive substrate>
Taking the conductive substrate 5 as an example,
(A) An unused conductive substrate 5 to which no potential is applied,
(B) 1.0 Vvs. Ag / AgCl, conductive substrate 5 applied for 100 hours,
(C) 1.0 Vvs. After applying Ag / AgCl for 100 hours, -1.4 Vvs. Using the conductive substrate 5 applied with Ag / AgCl for 30 minutes, the generation of chlorine as electrode activity was measured. The measuring method was the same as the chlorine measuring method.
As a result, it was confirmed that (A) and (C) generated substantially the same amount of chlorine. However, (B) was inferior to (A) and (C) in the reaction of chlorine generation. This is 1.0 Vvs. This is probably because the electrode surface was oxidized by applying Ag / AgCl for 100 hours to reduce the chlorine generation efficiency. Therefore, although detailed examination is required for the conductive material, the conductive substrate can be reactivated by applying a negative potential at least at T2, T3, T4, and T5.
Moreover, in the electroconductive base material 1, it is confirmed as a reduction | decrease in the amount of reaction current that platinum oxide is reduced and platinum elution occurs by application of a negative potential. However, by making them T1 and T6 steps again, they showed stable conductivity and were reactivated. Therefore, it is necessary to compare the performance of each process by various combinations depending on the substance present on the surface of the conductive substrate, and to stabilize the antifouling effect for a long period of time.
[0064]
<Verification of confirmation of reactivation of conductive substrate by controlling oxide formation and its reduction disappearance by scanning probe microscope>
Using the conductive substrate 22 as a representative example, the electrode surface when a potential was applied in accordance with the timing chart of FIG. 5 was observed with a scanning probe microscope (manufactured by Seiko Instruments Inc., SPI3800N). The application condition is that T1 is 0.9 Vvs. Ag / AgCl, 90 minutes, T2 -0.6 Vvs. Ag / AgCl, 45 minutes, T4 -1.4 Vvs. Ag / AgCl, 120 minutes. The sample was subjected to surface state observation of a new electrode to which no potential was applied, an electrode at the end of T1 application, and an electrode at the end of T4 application.
As a result, the unevenness accompanying the oxide film growth was observed at the end of T1, but the unevenness disappeared in the sample after the end of T4 and returned to almost the same state as the electrode surface to which no potential was applied. From this, it was found that the oxide film formed by applying a positive potential was restored to the same level as a new electrode surface to which no potential was applied by applying a low negative potential.
[0065]
【The invention's effect】
According to the electrochemical antifouling method according to the present invention, while maintaining and improving the function as an electrode of the conductive substrate that is the antifouling surface, the electrochemical antifouling effect of the antifouling conductive substrate is prolonged. In addition, the degree of freedom regarding the desorption step and the washing step can be increased. And the apparatus based on this electrochemical antifouling method is very useful because it can be reactivated to reproduce the antifouling effect for a long time without cost such as replacement of the conductive substrate. Device.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an apparatus according to an embodiment.
FIG. 2 is a timing chart of potential control.
FIG. 3 is a timing chart of potential control.
FIG. 4 is a timing chart of potential control.
FIG. 5 is a timing chart of potential control.
FIG. 6 is a timing chart of potential control.
[Explanation of symbols]
1 Control unit
2 Potentiostat
3 Conductive substrate
4 Reference pole
5 Counter electrode
6 Test tank
7 Stir bar
8 Stirrer
9 Positive potential electrolysis product generation potential
10 Negative potential electrolysis product generation potential
T1 Positive potential application process that does not generate electrochemical products
T2 Negative potential application process that does not generate electrochemical products
T3 Amplitude potential application process in the negative potential region where no electrochemical product is generated
T4 Negative potential application process for generating electrochemical products
T5 Amplitude potential application step in the negative potential region that generates / does not generate electrochemical products
T6 Positive potential application process for generating electrochemical products

Claims (9)

It consists of at least a conductive substrate, a counter electrode, and a power source that applies a voltage between the conductive substrate and the counter electrode, and is an electrochemical device that utilizes a direct electron transfer reaction between the conductive substrate and a living organism. In the antifouling method, the conductive base material comprises at least a part of the antifouling surface consisting of at least A) and B)
A) Platinum group metal selected from platinum, ruthenium, rhodium, palladium and iridium
B) Single metal oxide or mixed metal oxide or composite metal oxide selected from oxides of platinum, ruthenium, rhodium, palladium, iridium, titanium, zirconium, niobium, tantalum, manganese, cobalt, tin, and antimony < An aquatic organism that directly or indirectly contacts the surface of the conductive substrate by applying a positive potential that does not generate an electrochemical product from the electrolyte in at least the conductive substrate by the power source. An electrochemical antifouling method characterized by suppressing proliferation. It consists of at least a conductive substrate, a counter electrode, and a power source that applies a voltage between the conductive substrate and the counter electrode, and is an electrochemical device that utilizes a direct electron transfer reaction between the conductive substrate and a living organism. In the antifouling method, the conductive base material is a single metal oxide, mixed metal oxide or composite metal oxide in which a part or all of the antifouling surface is selected from at least platinum and / or metal oxide. The aforesaid aquatic organism that directly or indirectly contacts the surface of the conductive substrate by applying a positive potential that does not generate a product electrochemically from the electrolyte to the conductive substrate. An aquatic organism that directly or indirectly contacts the surface of the conductive substrate by applying a positive potential that electrochemically generates a product from the electrolytic solution to the conductive substrate while suppressing proliferation. And scale detachment Electrochemical antifouling method characterized by comprising the step of reactivating the purification and the conductive substrate.   By applying a positive potential that electrochemically generates a product from the electrolyte solution to the conductive substrate, desorption cleaning of aquatic organisms and scales that directly or indirectly contact the surface of the conductive substrate, and 3. The electrochemical antifouling method according to claim 2, wherein in the step of reactivating the conductive substrate, a chlorine compound or a radical is generated by applying a potential.   Furthermore, the step of desorbing aquatic organisms that directly or indirectly contact the surface of the conductive substrate by applying a negative potential that does not generate a product electrochemically from the electrolyte solution to the conductive substrate. The electrochemical antifouling method according to any one of claims 1 to 3, comprising:   Furthermore, by applying a negative potential that electrochemically generates a product from the electrolyte to the conductive substrate, aquatic organisms and scales that directly or indirectly contact the surface of the conductive substrate are desorbed. 5. The electrochemical antifouling method according to claim 1, further comprising a washing step.   The electrochemical antifouling method according to any one of claims 1 to 5, wherein the conductive substrate can be used as a counter electrode. The conductive substrate is a valve metal corrosion resistance conductive substrate, a part or the whole of the surface of the corrosion-resistant electrically conductive substrate, which is three-dimensionally carried on porous platinum and porous platinum platinum A coating comprising a single metal oxide, a mixed metal oxide or a composite metal oxide selected from oxides of rhodium, palladium, ruthenium, iridium, manganese, cobalt, tin, antimony, niobium, tantalum, zirconium and titanium The electrochemical antifouling method according to any one of claims 1 to 6, wherein a layer is formed . The conductive base material is a valve metal of a corrosion-resistant conductive base material, platinum that is dispersed and coated to such an extent that the surface of the corrosion-resistant conductive base material is partially exposed, and at least the exposure of the surface of the corrosion-resistant conductive base material An intermediate layer comprising at least one metal oxide of iridium, manganese, cobalt, tin, antimony, niobium, tantalum, zirconium and titanium covering the portion, and platinum, rhodium, palladium, ruthenium; And an outer layer composed of a mixed metal oxide layer made of a noble metal oxide of iridium and at least one metal oxide selected from valve metal oxides of niobium, tantalum, zirconium, and titanium. electrochemical antifouling method according to any of claims 1 to 6, wherein.   An aquatic organism that is in direct or indirect contact with the surface of the conductive base material and the conductive material, comprising at least a conductive base material, a counter electrode, and a power source that applies a voltage between the conductive base material and the counter electrode. An electrochemical antifouling device for controlling a direct electron transfer reaction with a conductive substrate, wherein a positive potential for electrochemically generating a product from an electrolyte is applied to the conductive substrate, A process for detaching and cleaning aquatic organisms and scales that directly or indirectly contact the surface of the conductive substrate and reactivating the conductive substrate can be set. The material has a positive potential at which no electrochemical product is generated from the electrolytic solution, a negative potential at which no electrochemical product is generated from the electrolytic solution, and a negative potential at which the electrochemical product is generated from the electrolytic solution. Potential can be set arbitrarily and can be applied periodically Electrochemical antifouling apparatus characterized and.

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