WO2007094189A1 - Photpcatalyst type antifouling device - Google Patents

Abstract

Generation of algae is prevented under underwater light receiving environment in the cooling tower, water purification tank, filter, and the like, of an air conditioner. In order to achieve the purpose, an antifouling object (2) immersed in the water (1) and receiving light on the surface serves as a first conductive member. A photocatalyst layer (3) is provided on the surface, i.e. the antifouling object surface. A second conductive member connected electrically with the conductive antifouling object (2) through an external circuit (4) is combined as a counter pole (5) and placed in the water (1). Algae prevention effect by the photocatalyst layer (3) is reinforced with no power supply through the use of the counter pole (5).

Description

 Specification

 Photocatalytic antifouling device

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a photocatalytic antifouling device effective for preventing generation of algae under an underwater light receiving environment such as a cooling tower, a purification water tank, and a filter of an air conditioner.

 Background art

 [0002] Conventionally, in equipment equipment that is in contact with water and receives light, such as a cooling tower, a purification tank, and a filter of an air conditioner, a large amount of algae is generated and adhered to the surface, and there is a problem that obstructs the equipment function. ing. In order to solve this problem, the work of removing algae has been frequently carried out in the past, but the problem is that the removal rate of algae needs to be removed quickly and frequently. In view of such circumstances, recently, various attempts have been made to prevent the generation of algae from various viewpoints, one of which is the use of a photocatalyst represented by titanium oxide (Patent Document 1). .

 [0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2004-249148

 [0004] When a photocatalyst is used for preventing algae, a photocatalyst such as titanium oxide is usually coated on the surface of the object to be prevented from contact with water and receiving light. The mechanism of anti-algae by photocatalyst is considered as follows. That is, it is considered that the oxidative power of the photocatalyst causes inactivation of adherent cells and decomposition of adhesive substances, resulting in weakened algal adherence and an excellent antialgae function.

 [0005] However, even if the photocatalyst is coated on the surface to be protected against algae, the actual situation is that the generation of algae can be sufficiently suppressed in the actual use environment.

 Disclosure of the invention

 Problems to be solved by the invention

[0006] An object of the present invention is to provide a photocatalytic antifouling device capable of effectively preventing the generation of various types of dirt in an underwater light receiving environment including the generation of algae.

 Means for solving the problem

[0007] In order to achieve the above object, the present inventor considers that the use of a photocatalyst is indispensable. The method of enhancing the function of the scientists was studied earnestly. As a result, we came to the conclusion that it is effective to combine a counter electrode electrically connected to the photocatalyst.

 That is, when the generation of algae on the surface of a metal material that is immersed in water and receives light is prevented by a photocatalyst, the surface of the metal material is coated with a photocatalyst, usually a TiO film. Coat photocatalyst

 2

 Then, it is true that the generation of algae can be suppressed compared to the case without coating, but it is only possible to extend the period until the generation of algae, and it is difficult to completely prevent the generation. . However, if the counter electrode, which is electrically connected to the metal material by an external circuit, is immersed in water together with the metal material, and both are made to conduct through the water, the generation of algae can be completely prevented even in the same operating environment. Or even if it cannot be completely prevented, the period until the algae emerges can be greatly extended.

 [0009] The photocatalytic antifouling device of the present invention has been completed on the basis of strong knowledge, and has a photocatalytic layer on the antifouling target surface that comes into contact with water and receives light. A first conductive member, and a second conductive member as a counter electrode that is in contact with the water and electrically connected to the first conductive member through an external circuit. This significantly increases the antifouling effect of the photocatalyst layer.

 In the photocatalytic antifouling device of the present invention, as shown in FIG. 1 (a), the antifouling object 2 that is immersed in water 1 and receives light on the surface is used as the first conductive member. A photocatalytic layer 3 is provided on the surface that is the surface to be antifouled. Then, the second conductive member as the counter electrode 5 is combined with the conductive antifouling object 2. The counter electrode 5 is immersed in the water 1 together with the antifouling object 2, and is electrically connected to the antifouling object 2 via the external circuit 4 while being electrically connected to the antifouling object 2. By using the counter electrode 5 as described above, the antifouling effect by the photocatalyst layer 3, for example, the anti-algae effect, is remarkably enhanced without a power source as compared with the case where the counter electrode 5 is not used.

 [0011] Further, as shown in Fig. 1 (b), if the external circuit 4 is provided with a power source 9 that conducts current from the counter electrode 5 to the antifouling target 2, the antifouling effect by the photocatalytic layer 3 is further enhanced. Is done.

The reason why the antifouling effect by the photocatalyst layer 3 is enhanced in the photocatalytic antifouling device of the present invention is considered as follows. When the counter electrode 5 does not exist, that is, when only the photocatalyst layer 3 is present, the anode and the cathode are mixed in various parts of the material of the photocatalyst layer 3, but by combining the counter electrode 5, the cathode and the anode are separated, and the positive cathode current (anode Side current and cathode side current) are equal. A current flows at a potential. As a result, the electrode potential can be easily controlled by changing the electrode surface area ratio, mass transfer by stirring, etc., and the antifouling effect can be enhanced by generating a current corresponding to the potential. If this power is added to the state force, the electrode potential can be forcibly changed, and the antifouling effect can be further improved by increasing the cathode current due to the potential difference.

 [0013] As the material of the second conductive member constituting the counter electrode 5, carbon, copper, various steels, and the like can be used. In the case of carbon, the point that the amount of current is large and the antifouling effect is high is particularly preferable. . The form of the second conductive member is not particularly limited. Further, the material and form of the first conductive member constituting the antifouling object are not particularly limited. The conductive plate material may be a coating film, fiber, porous body or the like. In the case of fibers and porous bodies, a photocatalyst layer can be provided not only on the exposed surface but also on the inside.

[0014] The light applied to the photocatalyst layer may be illumination light or sunlight, and the type thereof is not particularly limited. Photocatalysts react not only with visible light but also with ultraviolet light, and sunlight containing ultraviolet light has a wider effective band and is advantageous.

 The invention's effect

 [0015] The photocatalytic antifouling device of the present invention is a conductive antifouling object having an antifouling object having a photocatalyst layer on the surface that is in contact with water as the antifouling object surface. Combining a counter electrode that comes into contact with water with an object and is electrically connected to the antifouling target object via an external circuit significantly increases the antifouling effect including anti-algae by photocatalyst. It has a great industrial effect, such as maintaining long-term functions in air conditioner cooling towers, water purification tanks, filters, etc., and reducing maintenance costs. In addition, the countermeasures are simple, and this point power is also economical. Furthermore, since the effect can be obtained without a power source, it is excellent in economic efficiency, and if a separate power source is used, the antifouling effect can be further enhanced.

 BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic configuration diagram of the antifouling apparatus showing the first embodiment of the present invention. The antifouling device of this embodiment is an anti-algae device on the inner surface of a water storage tank 8 for storing outdoor water 1 such as a pool. Have been used.

 [0018] A thin conductive layer is formed as the first conductive member 2 on the inner surface of the water storage tank 8 which is a surface to be antifouled by applying a conductive paint or the like, and further on the surface of the first conductive member 2. Is TiO

 The photocatalytic layer 3 is formed as a coating. A second conductive member 5 as a counter electrode is immersed in the water 1 in the water storage tank 8. The second conductive member 5 is made of carbon such as graphite or charcoal, and is electrically connected to the first conductive member 2 via an external circuit 4 outside the water.

[0019] The water 1 in the water storage tank 8 contains an electrolyte and exhibits conductivity. When sunlight hits the inner surface of the water storage tank 8 that is in contact with the water 1 in the water tank 1 and is the target of antifouling, the light is emitted by the first conductive member 2 and the second conductive member 5 that have the photocatalytic layer 3 on the surface. An electrochemical cell is formed, and current flows from the second conductive member 5 to the first conductive member 2 through the external circuit 4. As described above, the electron transfer through the external circuit 4 enhances the algae-proofing effect on the bottom surface of the water storage tank by the photocatalyst layer 3.

 FIG. 3 is a schematic configuration diagram of an antifouling apparatus showing a second embodiment of the present invention. The antifouling device of this embodiment is used as an algae-proof device on the inner surface of a transparent aquarium 6 such as a fish breeding aquarium.

 [0021] A transparent electrode film having a force such as ITO is covered on the inner surface of the transparent water tank 6 as a first conductive member 2, and a photocatalyst layer 3 made of TiO is further formed on the surface.

 2

 A second conductive member 5 as a counter electrode is immersed in the water 1 in the transparent water tank 6. The second conductive member 5 is made of carbon such as graphite or charcoal, and is electrically connected to the first conductive member 2 via an external circuit 4 outside the water.

[0022] Water 1 in the transparent water tank 6 contains an electrolyte and exhibits conductivity. The water 1 comes into contact with the photocatalytic layer 3 coated on the inner surface of the transparent water tank 6. Since the transparent water tank 6 is transparent, the photocatalyst layer 3 coated on the inner surface of the transparent water tank 6 is exposed to sunlight or illumination light from the outside through the tank wall. Further, the inner force of the photocatalyst layer 3 is also exposed to sunlight or illumination light through the opening of the transparent water tank 6. As a result, the first conductive member 2 having the photocatalyst layer 3 on the surface and the second conductive member 5 form a photocatalytic battery, and the current flows from the second conductive member 5 to the first conductive member 2 through the external circuit 4. Flows. As described above, the electron transfer through the external circuit 4 enhances the algal barrier effect of the inner surface of the water tank 6 by the photocatalyst layer 3. FIG. 4 is a schematic configuration diagram of an antifouling apparatus showing a third embodiment of the present invention. The antifouling device of the present embodiment assumes an anti-algae device in a cooling tower of an air conditioner.

[0024] Assuming a cooling tower, the first conductive member 2, which is a metal material, is erected in the outdoor water storage tank 8, and the water 1 in the water storage tank 8 is pumped up by the pump 7 to be protected against algae. It is supplied to the surface of the first conductive member 2 which is a surface and flows down along the surface. A photocatalytic layer 3 made of TiO is coated on the surface of the first conductive member 2. Meanwhile, water storage

 2

 In the water 1 in the tank 8, a second conductive member 5 as a counter electrode is immersed. The second conductive member 5 is made of carbon such as graphite or charcoal, and is electrically connected to the first conductive member 2 via the external circuit 4. Further, the surface is electrically connected to the second conductive member 5 in the water 1 through the water flowing down along the surface of the first conductive member 2.

 [0025] When the first conductive member 2 and the second conductive member 5 are exposed to sunlight on the surface of the first conductive member 2 that is the surface of the algae control, particularly the photocatalyst layer 3 formed on the surface, Thus, a photocatalytic cell is formed, and a current flows from the second conductive member 5 to the first conductive member 2 through the external circuit 4. As described above, the electron transfer through the external circuit 4 enhances the anti-algae effect on the surface of the first conductive member 2 by the photocatalytic layer 3.

 [0026] Even in the embodiment of the V deviation, it is possible to provide the external circuit 4 with a power source for passing a current from the second conductive member 5 to the first conductive member 2, and thereby on the surface of the photocatalytic layer 3. Reaction is promoted, and the algal control effect is further enhanced.

 Example

 [0027] The following comparative test was conducted to prove the effect of the present invention. A stainless steel plate of A4 size was placed upright on an outdoor aquarium, and its lower end was immersed in industrial water in the aquarium. The stainless steel plate was directed south and inclined at 50 to 60 degrees with respect to the horizon so that the sunlight hits the surface of the stainless steel plate. We pumped industrial water in the tank day and night, and continued to supply it to the entire surface of the photocatalyst layer of stainless steel plate.

[0028] In the case of Comparative Example 1 in which the surface of the stainless steel plate is not coated with a photocatalytic layer, that is, in the case of Comparative Example 1 in which no measures are taken against algae, the surface of the steel plate (sunlight hits) after 27 days from the start of the experiment. The side surface was covered with algae. [0029] As Comparative Example 2, TiO was used as a photocatalyst layer on the surface of a stainless steel plate by a CVD method.

 2

 Coated to a thickness of nm. In this case, 35 days after the start of the experiment, the surface of the steel plate (the surface exposed to sunlight) was completely covered with algae.

[0030] As Example 1, the surface of a stainless steel plate was covered with a photocatalyst layer, and a counter electrode electrically connected to the stainless steel plate with an external circuit was immersed in industrial water in a water tank. As a counter electrode, a carbon plate having a plate thickness of 8 mm and an immersion part size of 40 mm × 110 mm was used. In this case, the entire surface was covered with algae 50 days after the start of the experiment.

[0031] As Example 2, a silicon solar cell was interposed in the external circuit in Example 1.

. In this case, the entire surface was not covered with algae until 100 days after the start of the experiment.

 [0032] As Example 3, the stainless steel plate in Example 1 was changed to an A4 size titanium plate. In this case, the entire surface was not covered with algae until 71 days after the start of the experiment.

 Brief Description of Drawings

FIG. 1 is a principle diagram of an antifouling device of the present invention.

 FIG. 2 is a schematic configuration diagram of an antifouling apparatus showing a first embodiment of the present invention.

 FIG. 3 is a schematic configuration diagram of an antifouling apparatus showing a second embodiment of the present invention.

 FIG. 4 is a schematic configuration diagram of an antifouling apparatus showing a third embodiment of the present invention.

 Explanation of symbols

[0034] 1 water

 2 Antifouling object (first conductive member)

 3 Photocatalyst layer

 4 External circuit

 5 Counter electrode (second conductive member)

 6 Clear water tank

 7 Pump

 8 Water tank

 9 Power supply

Claims

The scope of the claims  [1] A first conductive member as an antifouling object having a photocatalyst layer on the surface of the antifouling object that comes into contact with water and receives light; and the first conductive member in contact with the water and through the external circuit A photocatalytic antifouling device comprising a second conductive member as a counter electrode that is electrically connected to a conductive member, and exhibits an antifouling effect when the photocatalytic layer receives light. [2] The photocatalytic antifouling device according to [1], wherein the external circuit includes a power source for passing a current from the second conductive member to the first conductive member. 3. The photocatalytic antifouling device according to claim 1, wherein the second conductive member is carbon. [4] The photocatalytic antifouling device according to [1], wherein the antifouling effect includes an antialgal effect. 5. The photocatalytic antifouling device according to claim 1, wherein the first conductive member is a conductive plate material, a coating film, or a fiber.