JPH08268823A - Antibacterial agent - Google Patents

Abstract

PURPOSE: To obtain an antibacterial agent effective for controlling a sulfur- oxidizing bacterium and sulfur-oxidizing iron-oxidizing bacterium belonging to the genus Thiobacillus which causes the deterioration of a concrete structure in a sewage treatment plant, etc., by attaching a thickener to the surface of metal powder, etc., insoluble in water and soluble in sulfuric acid. CONSTITUTION: This antibacterial agent is produced by attaching a thickener such as methyl cellulose, hydroxyethyl cellulose, polyacrylic acid, polyacrylamide, pullulan or alginic acid to the surface of powdery metal (e.g., nickel, tin or copper) and/or powdery metal compound (e.g., nickel oxide, tin oxide, cobalt oxide or cuprous oxide) insoluble in water and soluble in sulfuric acid and having particle diameter of preferably 0.005-0.mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antibacterial agent which is incorporated into concrete to prevent sulfur-oxidizing bacteria and sulfur-iron oxide-oxidizing bacteria, and more specifically, it belongs to the genus Thiobacillus in sewage treatment facilities. The present invention relates to an antibacterial agent capable of preventing deterioration of concrete due to sulfur oxidizing bacteria and sulfur iron oxide oxidizing bacteria.

[0002]

2. Description of the Related Art Conventionally, it has been known that hydrogen sulfide generated from a sewage treatment facility or the like causes a concrete structure to become gypsum and deteriorate. This deterioration is generally present widely in soil and water, and sulfur-oxidizing bacteria of the genus Thiobacillus and sulfur-oxidizing iron bacteria, which grow by assimilating carbon dioxide by the oxidation of sulfur compounds, oxidize hydrogen sulfide to produce sulfuric acid. Is considered to be the cause and various prevention methods have been proposed. Specifically, a method of suppressing the formation of sulfide,
A method for suppressing generation of hydrogen sulfide, a method for suppressing generation of sulfuric acid from hydrogen sulfide, and a method using a corrosion-resistant material have been proposed.

However, each method has some drawbacks such as economical efficiency, workability, and generation of a bad odor.

Although a method of adding a fungicide consisting of an organic compound to concrete has also been proposed, it has a drawback that the concrete itself suffers from pinholes, cracks and the like and the durability of the concrete itself is lowered.

Further, a method has been proposed in which metal powder is mixed with concrete to prevent deterioration of concrete in a sewage treatment facility or the like. However, when the metal powder is mixed in concrete, it is difficult to evenly disperse the metal powder, and in order to impart the same deterioration preventing ability to the entire concrete structure, the mixing control of such metal powder is required. Need to do enough. Further, if the mixing position of the metal powder in the concrete is not uniformly controlled, the strength of the obtained concrete structure itself may be affected.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to effectively and effectively prevent sulfur oxidizing bacteria and sulfur iron oxide oxidizing bacteria that cause concrete deterioration in sewage treatment facilities and the like for a long period of time. It is to provide an antibacterial agent capable of Another object of the present invention is to prevent sulfur-oxidizing bacteria and sulfur-iron oxide-oxidizing bacteria that cause deterioration of concrete in sewage treatment facilities,
It is an object of the present invention to provide an antibacterial agent which can be easily uniformly mixed into concrete and which does not substantially reduce the strength of the concrete structure itself.

[0007]

According to the present invention, a bactericidal agent, which is incorporated in concrete to prevent sulfur-oxidizing bacteria and sulfur-iron oxide-oxidizing bacteria, is insoluble in water,
There is provided a bactericidal agent comprising a metal powder and / or a metal compound powder soluble in sulfuric acid and a thickener attached to the surface of the powder.

The present invention will be described in more detail below. The antibacterial agent of the present invention is for preventing sulfur-oxidizing bacteria and sulfur-iron oxide-oxidizing bacteria of the genus Thiobacillus that cause deterioration of concrete structures in sewage treatment facilities, etc. It is considered that it exhibits a bactericidal action by reacting with the sulfuric acid generated by the action of to form a sulfate salt.

The antibacterial agent of the present invention is a metal powder which is insoluble in water and soluble in sulfuric acid and / or a metal compound powder which is insoluble in water and soluble in sulfuric acid (hereinafter, these are referred to as "bactericidal agent raw material powder"). (Referred to as ")) with a thickener attached to its surface.

Examples of the antibacterial agent raw material powder include metals such as nickel, tin and copper; metal oxides such as nickel oxide, tin oxide, cobalt oxide and cuprous oxide, and mixtures thereof. The particle size of the antibacterial agent raw material powder is
When blended with concrete, it is possible to effectively exhibit a bactericidal action, and a grain size that is blended at a desired position in concrete during concrete molding is preferable, and specifically 0.005-0.2 mm is desirable. . The particle size is 0.2
If it exceeds mm, the desired antibacterial action may be deteriorated, which is not preferable.

The thickening agent to be adhered to the antibacterial agent raw material powder is a simple control when the antibacterial agent is mixed in the concrete, and the antibacterial agent is uniformly mixed in the concrete, and the concrete structure itself. A material that acts to effectively exhibit a bactericidal action without lowering the strength of, for example, a cellulosic thickener such as methyl cellulose or hydroxyethyl cellulose; polyacrylic acid, polyacrylic amide, pullulan, alginic acid, etc. Can be mentioned.

The antibacterial agent of the present invention can be prepared by attaching the thickener to the antibacterial agent raw material powder. The adhesion can be performed, for example, by a method in which a thickener is preferably used as an aqueous solution having a concentration of 0.01 to 1% by weight, and the antibacterial agent raw material powder is dipped in the thickener aqueous solution and then dried. . The adhesion amount of the thickener is not particularly limited, and it is preferable that the entire surface of the antibacterial agent raw material powder is covered with the thickener film. Particularly preferably, the film thickness is 0.1 to 10
An adhesion amount of about 0 μm is desirable.

In order to prevent sulfur-oxidizing bacteria and sulfur-iron oxide-oxidizing bacteria by using the antibacterial agent of the present invention and prevent deterioration of concrete derived from these bacteria, the antibacterial agent is added to the concrete. It may be mixed, and the mixing ratio is
For 100 parts by weight of the cement component in concrete,
It is preferably 0.001 to 1 part by weight, particularly preferably 0.01 to 0.2 part by weight. When the blending ratio is less than 0.001 part by weight, it is difficult to maintain the antibacterial action against sulfur-oxidizing bacteria and sulfur-iron oxide-oxidizing bacteria for a long period of time. It is not preferable because improvement of the bactericidal action cannot be expected and there is a risk of cost problems.

The antibacterial agent can be added to the concrete by, for example, adding a desired amount to the concrete composition, and molding and curing by a known method. Particularly, the antibacterial agent can be easily and evenly mixed in the concrete by the centrifugal molding method. This centrifugal molding method can be performed in the same manner as a known method for producing a fume tube or the like, and by appropriately selecting the centrifugal molding conditions, concrete having a desired antibacterial agent can be obtained. Further, in the centrifugal molding method, the particle size of the antibacterial agent is important, and if the particle size is too small, it moves together with breathing water during centrifugal molding and may be drained in some cases, while the particle size is If it is too large, it may move to the outer surface side during centrifugal molding, so it is desirable to set the particle size within the above-mentioned preferred range.

[0015]

The antibacterial agent of the present invention has a thickening agent attached to the surface thereof, so that even if a centrifugal molding method is adopted when compounding it in concrete, it is easy to mix it evenly. It is possible to effectively and effectively prevent sulfur-oxidizing bacteria and sulfur-oxidizing iron-oxidizing bacteria that cause deterioration of concrete in sewage treatment facilities, etc., for a long period of time without reducing the strength of the concrete structure itself. it can.

[0016]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples below, but the present invention is not limited thereto.

[0017]

Example 1 A nickel powder having a particle diameter of 0.1 to 0.2 mm was immersed in a methylcellulose aqueous solution having a concentration of 1% by weight, stirred for 30 minutes, and then dried, and methylcellulose as a thickener was adhered to the surface. A fungicide was obtained. Next, 0.1 part by weight of the antibacterial agent was mixed in a concrete composition consisting of 480 parts by weight of cement, 197 parts by weight of water, 836 parts by weight of fine aggregate and 833 parts by weight of coarse aggregate of 5 to 13 mm. Using the concrete composition containing this antibacterial agent,
With a centrifugal acceleration of G, a fume tube having an outer diameter of 20 cm and an inner diameter of 12 cm was produced. 1 cm from the outer surface of the obtained fume tube
And a portion 1 cm from the inner surface are measured with an X-ray microanalyzer (made by JEOL Ltd.),
The ratio of the X-ray intensity of the contained antibacterial agent was measured. In addition, the antibacterial agent strength ratio in the reitance portion was also measured. The results are shown in Table 1.
Shown in In addition, each X-ray intensity ratio is 100 times the X-ray intensity of the outer surface.
Express as.

Next, the obtained fume tube and the fume tube produced in the same manner except that the antibacterial agent was not added were exposed to the aerial part of the sludge facility of the sewage treatment plant, and the exposed surface part was observed for one year. As a result, no deterioration that could be attributed to sulfur-oxidizing bacteria and iron oxide-oxidizing bacteria was observed in the fume tube containing the antibacterial agent, but it was found that the fumed tube containing no antibacterial agent contained sulfur-oxidizing bacteria and sulfur iron oxide. Defects and gypsum formation, which were probably due to oxidizing bacteria, were observed on the entire surface.

[0019]

Comparative Example 1 A fume tube was prepared in the same manner as in Example 1 except that nickel powder having a particle size of 0.1 to 0.2 mm was used as the antibacterial agent, and the X-ray intensity ratios were measured. The results are shown in Table 1.

[0020]

Example 2 Nickel oxide having a particle diameter of 0.01 to 0.05 mm was immersed in an aqueous solution of hydroxyethyl cellulose having a concentration of 0.5% by weight, stirred for 30 minutes, and then dried to give hydroxy as a thickener on the surface. A bacteriostatic agent having ethyl cellulose attached was obtained. A fume tube was prepared in the same manner as in Example 1 except that the antibacterial agent having hydroxyethyl cellulose attached was used as the antibacterial agent, and the X-ray intensity ratios were measured. The results are shown in Table 1.

Next, the obtained fume tube and the fume tube produced in the same manner except that the antibacterial agent was not added were exposed to the aerial part of the sludge facility of the sewage treatment plant, and the exposed surface part was observed for one year. As a result, no deterioration that could be attributed to sulfur-oxidizing bacteria and iron oxide-oxidizing bacteria was observed in the fume tube containing the antibacterial agent, but it was found that the fumed tube containing no antibacterial agent contained sulfur-oxidizing bacteria and sulfur iron oxide. Defects and gypsum formation, which were probably due to oxidizing bacteria, were observed on the entire surface.

[0022]

[Comparative Example 2] Particle size of 0.01 to 0.05 m as an antibacterial agent
A fume tube was produced in the same manner as in Example 1 except that the nickel oxide powder of m was used, and each X-ray intensity ratio was measured. The results are shown in Table 1.

[0023]

[Table 1]

Claims (2)

[Claims] 1. A bactericidal agent which is incorporated into concrete to prevent sulfur-oxidizing bacteria and sulfur-iron oxide-oxidizing bacteria and is insoluble in water and soluble in sulfuric acid.
Alternatively, a bactericidal agent comprising a thickener attached to the surface of the metal compound powder. 2. The particle size of the powder is 0.005-0.2 m
The antibacterial agent according to claim 1, which is m.