JPH02163028A - Electrode plate for soil - Google Patents

Abstract

PURPOSE:To obtain electrode plate for soil capable of stably performing electrolysis reaction for long period of time by burying electrically-conductive substrate in protecting layer comprising of electrically-conductive elastomer or resin containing highly electrically-conductive material such as carbon black and covering the surface with filter layer made of porous material. CONSTITUTION:An electrically-conductive substrate 3 jointed with a terminal 2 is buried in protecting layers 4 composed of electrically-conductive elastomer or resin containing at least one highly electrically-conductive material selected from highly electrically-conductive carbon black, graphite or glassy carbon to form an electrode material 5. Then, further the surface of the electrode material 5 is covered with filter layer 6 composed of porous material (e.g., nonwoven cloth or synthetic resin foam) to form an electrode plate 1 for soil. Two of said electrode plates 1 for soil are buried in soil with suitable interval and direct voltage is applied, thus germ or microorganism is efficiently controlled by electrical method.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrode plate for soil, and for example, to an electrode plate for soil used in a method for electrically exterminating pathogenic bacteria or microorganisms in soil.

(Prior Art) Conventionally, a method has been proposed for electrically exterminating specific pathogenic bacteria or microorganisms in soil by burying a pair of electrodes in moist soil and applying a DC voltage to the electrodes. . Examples include JP-A-58-127127 and JP-A-62-259533. According to these methods, continuous cropping damage caused by microorganisms such as nematodes or pathogenic bacteria can be prevented, and continuous cropping can be made possible.

However, the electrodes employed in these methods were generally metals such as copper plates or graphite.

(Problem to be Solved by the Invention) However, the surface of the metal plate electrode is corroded by moisture in the soil, especially the anode electrode, in a short period of time, so it lacks durability and risks contaminating the soil. Precious metals such as platinum and gold do not have to worry about such corrosive properties, but they are not economically practical.

Furthermore, in graphite electrodes, the graphite used in the anode is oxidized and graphite particles fall off, making it impractical from an economical point of view.

An even bigger problem is that soil particles adhere to the surface of the electrode, and gas generated by the electrolytic reaction remains, making it difficult for current to flow.

The present invention solves these problems, and even when used in soil, it prevents soil from adhering to the electrode surface and prevents gas from remaining, making it possible to use the electrode for a long time, and increasing the surface area of the electrode. The purpose of the present invention is to provide an electrode plate for soil with improved current efficiency.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, the conductive base material is made of at least one highly conductive material selected from highly conductive carbon black, graphite, or glassy carbon. The filter layer is embedded in a conductive elastomer or resin protective layer, and the surface thereof is covered with a filter layer made of a porous material.

It also includes an electrode plate for soil in which a conductive surface layer with an uneven surface is formed on the surface of the protective layer.

It also includes an electrode plate for soil in which a conductive surface layer with an uneven surface is formed on the protective layer and a filter layer made of a porous material is coated on the surface.

Furthermore, there is also an electrode plate for soil in which the protective layer is provided with a conductive surface layer having an uneven surface, this surface is covered with a filter layer made of a porous material, and this is placed in a housing material having communicating holes. include.

(Function) In the above electrode plate for soil, the filter layer made of a porous material coated on the surface of the protective layer blocks the intrusion of micro soil particles in the soil and prevents them from adhering to the surface of the electrode material. It allows the passage of water, and 1! It has the function of activating the electrolytic reaction on the surface of the electrode material and maintaining it for a long time. That is, the soil is separated from the electrode reaction surface and the gas generated at the reaction surface is released.

In addition, since the protective layer has a conductive surface layer with an uneven surface, the surface area of the electrode itself increases, making it possible to flow a large amount of current with a constant voltage and increase current efficiency. When a constant current is applied, the voltage can be lowered, thereby extending the life of the electrode plate and reducing the electrophoresis of charged particles in the soil.

Furthermore, if the surface of the electrode material is sequentially coated with a conductive layer having an uneven surface and a filter layer made of a porous material, the conductive surface area increases and this surface is also sufficiently protected by the filter layer. Deterioration of the surface layer is also prevented.

Furthermore, the housing material having a plurality of communicating holes prevents the electrode material from being damaged and deformed, prevents relatively large soil particles from entering, and also prevents moisture from being introduced into the housing material. Activates the electrolytic reaction of the electrode plate.

(Example) Hereinafter, an example of the present invention will be described based on the drawings, and FIG. 1 is a partially sectional perspective view of an electrode plate for soil according to the present invention. In the figure, the soil electrode plate (1) is made of a conductive elastomer or resin containing a highly conductive material such as highly conductive carbon black, graphite, or glassy carbon. Protective layer (4)
An electrode material (5) embedded in the electrode material (5) and a filter layer (6) made of a porous material covering the surface of the protective layer (4) are coated without adhering to the surface of the protective layer (4).

This filter layer (6) prevents the intrusion of micro soil particles in the soil, allows the passage of power water, protects the electrode material surface (7), and activates the electrolytic reaction on the surface. be. Non-woven fabrics, woven fabrics,
Examples include paper and foam with open cells. The thickness of the filter layer (6) varies depending on the performance of the filter material and is not particularly defined.

The protective layer (4) has the function of protecting the conductive base material (3) and preventing the oxidation and elution of metals attached to the textile, and at the same time protects the conductive base material (3) or this material from the surface. It has the ability to efficiently transfer electrons in the opposite direction.

The thickness of this protective layer (4) is 0.1 mm to 5 mm. It is about Qmm.

The conductive base material (3) is made of organic fiber yarn made of polyester, polyamide, aromatic polyamide, etc., and has various textures such as satin, twill, and plain weave. The threads constituting this fabric are those that have been vapor-deposited or chemically plated with a conductive material such as nickel, copper, or zinc, or the fabric is vapor-deposited or chemically plated with a conductive material.

Furthermore, a metal fabric, mesh, or metal plate may be used. The surface resistance value of the conductive base material (3) is a maximum of 20 Ω/hole, and if it exceeds this value, it lacks conductivity and cannot be used. Further, the maximum thickness is about IQ mm.

The protective layer (4) can be used in water, alkaline or acidic soil, and can be used, for example, in natural rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, butyl rubber, chloroprene rubber, ethylene-propylene rubber, etc. Elastomers such as polymer rubber, silicone rubber, and fluororubber contain highly conductive materials, oil, etc., and use rubber that can be crosslinked with sulfur, sulfur compounds, or peroxides to improve mechanical strength and heat resistance. However, 515. SBS, 5E
Thermoplastic elastomers such as BS are also used.

Of course, thermoplastic resins such as vinyl chloride, polyethylene, polypropylene, etc. can also be used.

The highly conductive member contains not only highly conductive carbon but also graphite, glassy carbon, etc., and the amount added in the protective layer (4) is 10 to 150 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the elastomer. It is 100 parts by weight. If the amount is less than 10 parts by weight, the resistance value will be large and the current efficiency will be poor; if it exceeds 150 parts by weight, workability will be difficult and flexibility will also be impaired.

The highly conductive carbon used here has a DBP oil absorption of 1
50m1/100g or more, preferably 400m1/1
00 g or more, the amount of iodine adsorbed is 100 mg/g or more, or the nitrogen surface area is 150 m''/gg or more, a chain structure has developed, and the distance between particles and aggregates is small, such as highly conductive furnace black or acetylene. There are black etc.

In addition, especially when using silicone rubber or fluorine rubber as the protective layer (4), this highly conductive carbon has a DBP oil supply amount of 300 to 600 ml/100 g, an iodine adsorption amount of 800 to 2000 mg/g, and a nitrogen surface area of 300 to 600 ml/100 g. 80
0 to 2000 m2/g, has a developed chain structure, and has very small distances between particles and between aggregates, such as Ketchien EC (manufactured by Agzo), Printex XE-
2 (manufactured by Degussa), etc.

The amount of carbon added is 10 to 30 parts by weight per 100 parts by weight of silicone rubber or fluororubber.
It has been confirmed that when the amount is less than 1 part by weight, the electrolytic current value rapidly decreases in a short period of time. This is thought to be because the carbon chain is insufficient, the resistance is high, and the oxidation and elution of carbon easily progresses during electrolysis.

On the other hand, if the amount exceeds 80 parts by weight, it becomes substantially difficult to mix carbon into the elastomer.

In addition, the silicone rubber or fluororubber used for the protective layer (4) has a structure in which the main chain of the skeleton is not directly oxidized and has very few oxidation points. Moreover, the side chain is preferably a methyl group or a phenyl group, which is more difficult to oxidize than an ethyl group or a propyl group. Silicone rubbers having such a structure include methylvinylsiloxane polymers, fluorosilicone rubbers in which CF2 is introduced into the main chain, and fluorosiloxane-dimethylsiloxane copolymers.

Furthermore, fluororubbers include vinylidene fluoride, tetrafluoroethylene-propylene, fluorine-containing silicone, fluorine-containing nitrile, fluorine-containing vinyl ether, fluorine-containing triazine, and fluorine-containing phosphazene.

FIG. 2 is a longitudinal cross-sectional view of another soil electrode plate (1) of the present invention,
It also shows an enlarged view of part A in Figure 3, in which an uneven surface (8) is formed on the surface of a conductive material (5) in which a conductive base material (3) having a terminal is embedded in the above-mentioned protective layer (4). A conductive surface layer (9) is formed.

The surface layer (9) is integrated with the protective layer (4) or is made of a different material, and is in close contact with the protective layer (4).
), and the electrolytic reaction is carried out on the uneven surface (8) with an increased surface area. The surface layer (9) used here is a conductor, and its constituent material is preferably the same as that used for the protective layer in consideration of its adhesion to the protective layer, but as long as the adhesion does not deteriorate, The purpose of the invention is fully achieved. Examples of its constituent materials are the same as those for the protective layer.

FIG. 4 is a longitudinal cross-sectional view of another soil electrode plate of the present invention,
The soil electrode plate (1) has a conductive material (5) in which a conductive base material (3) having a terminal is embedded in a protective layer (4), and a conductive surface layer (8) having an uneven surface (8). 9) and filter layer (6
) are sequentially laminated.

This increases the surface area for electrolytic reactions, and the filter layer (6) provides sufficient protection to this surface. That is, microscopic soil particles do not adhere to the surface where the electrolytic reaction occurs, and the activation of the electrolytic reaction is maintained for a long time by the penetration of force water.

Moreover, the gas generated by this reaction is also released to the outside from the communicating holes of the filter layer without remaining.

Furthermore, FIG. 5 is a partially cross-sectional perspective view of another soil electrode plate of the present invention, and this soil electrode plate (1) has a conductive base material (3) having a terminal as a protective layer (4). Buried conductive material (5)
A box-shaped housing material (
10).

The housing material (10) prevents deformation of the electrode material and must not be significantly deformed with respect to the tonosho,
It also has a plurality of through holes (11) for introducing water into the interior. For this reason, examples of the housing material (10) include plastic, ceramic, wood, and the like.

Next, the present invention will be explained in more detail using specific examples.

(Example 1) 100 parts of SIS compound (Freighton D1111 manufactured by Shell Chemical Co., Ltd.), 80 parts by weight of acetylene black and NT-100 oil (cycloaliphatic, manufactured by Fuji Kosan Co., Ltd.)
After kneading the mixture in a Banbury mixer, two sheets were prepared by rolling the mixture to a thickness of 1+ nm using a roll. Approximately 13 g/m" of nickel was attached to a plain weave polyester fabric between the above sheets, resulting in a surface resistance value of 5 to 10 Ω/
This laminate was heated to a temperature of 1 with the fabric having openings sandwiched between them.
After installing it in a press machine at 50° C., pressure vulcanization was performed for about 20 minutes to produce an electrode material (sample 1). This electrode material had a thickness of 15 mm, a width of 75 mm, and a length of 135 mm, and the thickness of the protective layer formed on the surface of the conductive fabric was about 1 mm.

Next, felt (320 mg/cm2' of cotton) having a thickness of 3 mrn was wrapped around the surface of the conductive material of Sample 1 to obtain a soil electrode plate of Sample 2 (same structure as in FIG. 1).

In addition, as Sample 3, a conductive urethane foam (Elmic H, manufactured by Hayashi Felt Co., Ltd.) consisting of open cells with a thickness of 3 mm was attached to the surface of the conductive material of Sample 1 with an adhesive (obtained from the rubber compound used for the electrode material). A soil electrode plate (showing the same structure as in FIG. 3) was obtained by adhering it with conductive rubber glue (conductive rubber glue).

In addition, as sample 4, a thickness of 3 was added to the surface of sample 2.
+nm felt (cotton 320 mg/cn+2) was wrapped to obtain a soil electrode plate (showing the same structure as in FIG. 4).

Further, as Sample 5, a soil electrode plate (same structure as in FIG. 5) was obtained in which Sample 4 was installed in a polyacrylate housing material having a through hole with a diameter of 1 mm.

These same electrode plates were inserted into soil containing 40% water by weight, the distance between the electrode plates was set to 5 Qmm, and a constant current (
A direct voltage of 5 mA/cm2) was applied, and the time required for the voltage to rise from the initial voltage to 20V (stable current supply time) was measured. The results are shown in Table 1.

Table 1: According to the results, the soil electrode plate of the present invention has a longer stable energization time than conventional products, especially in the structure where the filter layer is covered or the filter layer and the housing material are covered. In particular, this suggests that the stable energization time becomes longer and the life of the electrode plate becomes longer.

(Effects) As described above, in claims 1 and 3, by providing a filter layer, the intrusion of microparticles in the soil is prevented, and moisture reaches the electrolytic reaction surface, thereby prolonging the electrolytic reaction on the surface. It has the effect of being able to maintain a stable energization time.

In addition, in the soil electrode plate according to claim 2, since a conductive surface layer with an uneven surface is formed on the electrode material, the surface area of the electrode itself increases, making it possible to flow a large amount of current. In addition, in claim 4, the electrode material is protected by using a housing material that can withstand earth pressure, and by introducing water into the interior, the current efficiency can be maintained even more stably for a long time. It has the effect of

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional perspective view of the soil electrode plate according to claim 1, FIG. 2 is a vertical cross-sectional view of the soil electrode plate according to claim 2, and FIG. 3 is an enlarged view of section A in FIG. , FIG. 4 is a longitudinal sectional view of the soil electrode plate according to claim 3, and FIG. 5 is a longitudinal sectional view of the soil electrode plate according to claim 4. (1)... Electrode plate for soil (3)... Conductive base material (4)... Protective layer (5)... Electrode material (6)... Filter layer (8)... Irregular surface (9)...Conductive surface layer (10)...Housing material (11)...Through hole Fig. 2 Fig. 3

Claims (1)

[Claims] 1. A conductive base material is embedded in a protective layer of a conductive elastomer or resin containing at least one highly conductive material selected from highly conductive carbon black, graphite, or glassy carbon, This soil electrode plate has a filter layer made of porous material coated on its surface. 2. A conductive base material is embedded in a protective layer of conductive elastomer or resin containing at least one highly conductive material selected from highly conductive carbon black, graphite, or glassy carbon, and an uneven surface is formed on the surface. Electrode plate for soil with a conductive surface layer. 3. The soil electrode plate according to claim 2, wherein the conductive surface layer formed on the surface of the protective layer is covered with a filter layer made of a porous material. 4. The soil electrode plate according to claim 1, 2 or 3, wherein a housing material having communicating holes is disposed in the outermost layer.