JP6915235B2 - Patina processing method - Google Patents

Description

The present invention relates to a patina treatment agent and a patina treatment method for removing patina generated in a copper-based member or preventing patina generation.
The present invention also has a higher immediate effect on Legionella, an effect on bacteria and molds, a slime control effect and a bactericidal effect on a wider range of microorganisms, and an anticorrosive effect on copper. Also, the present invention relates to a water treatment agent and a water treatment method that do not promote corrosion of iron-based members.

Copper-based members that come into contact with water systems such as cooling water systems, boiler water systems, scrubber water systems, pulp and paper water systems, and film-treated water systems have problems of corrosion and pitting corrosion. Patina and slime are examples of causes of corrosion and pitting corrosion of copper-based members.

Conventionally, hydrazine has been reported as a patina removing agent for copper-based members (Patent Document 1), but hydrazine is a substance suspected to be carcinogenic and is also a PRTR target substance, and its use is not preferable.

As a patina remover that does not use hydrazine, a combination of thioglycolic acid or a salt thereof and an azole-based copper anticorrosive agent has been reported (Patent Document 2). In addition, the combined use of carbohydrazide and an azole-based copper anticorrosive agent has also been reported (Patent Document 3). Since both of these are used in combination with two drugs, there are problems in terms of drug management and drug injection control.

On the other hand, as a typical drug conventionally used as a slime control agent, there are inorganic halogen compounds such as sodium hypochlorite (NaClO), but these have a problem in their high corrosiveness, for example. , When used for sterilization of Legionella, etc., it is necessary to strictly control the concentration in order to suppress corrosion. Further, it is necessary to use an anticorrosive agent in combination, and an azole compound such as benzotriazole is used as the anticorrosive agent.

Isothiazolin compounds are widely used for slime control and Legionella sterilization, but isothiazolin compounds have a problem of lacking immediate effect in sterilization (Non-Patent Document 1). In addition, since the isothiazolin compound is also corrosive to metals, it is generally necessary to use an anticorrosive agent in combination.

In addition, when there is a wastewater treatment facility using organisms in the latter stage, the higher the effect of the slime control agent, the more adversely it affects the activated sludge in the latter stage.

As described above, in the past, there have been the following problems.
(1) Anticorrosive agents do not have slime control ability, while slime control agents and fungicides have a problem of corrosion. For this reason, strict concentration control and addition of anticorrosive agents are required when sterilizing and slime control in equipment using metals, especially copper-based members.
(2) Slime control agents and fungicides that are weakly corrosive lack immediate effect.
(3) Rapid sterilization is usually required for sterilization of Legionella and the like, but rapid sterilization cannot be performed with chemicals that are weakly corrosive.
(4) Wastewater that has undergone slime control / sterilization treatment is usually treated at a wastewater treatment facility, but when wastewater containing a high concentration of slime control agent or fungicide flows into the activated sludge treatment tank, activated sludge Is hindered.

Dimer-type pyridinium compounds (Patent Document 4) and bis-type quaternary ammonium salts (Patent Document 5) have been reported as agents having both anticorrosive and bactericidal effects, but they have immediate effects on a wider range of microorganisms. A drug that exhibits a certain slime control effect and bactericidal property and has more excellent anticorrosion property is desired.
In addition, an inorganic oxidant having excellent immediate effect such as sodium hypochlorous acid and an organic bactericidal agent (slime control agent) having excellent durability such as isothiazoline compound, dichloroglioxide, and dibromonitroethanol are used in combination. An aqueous sterilization method has been proposed (Patent Document 6), but in this case as well, concentration control for suppressing metal corrosion is required.

Japanese Unexamined Patent Publication No. 61-272392 Japanese Unexamined Patent Publication No. 2008-248303 Japanese Unexamined Patent Publication No. 2012-12698 Japanese Unexamined Patent Publication No. 2001-310191 Japanese Unexamined Patent Publication No. 2003-290778 Japanese Unexamined Patent Publication No. 2015-117216

Research Report of the Council of Air-Conditioning Water Treatment Agents for Anti-Legionella The bactericidal performance of organic fungicides used in anti-Legionella air-conditioning water treatment agents against Legionella spp. May 2000 Japan Antibacterial and Antifungal Society 27th Annual Meeting

An object of the present invention is to provide a patina treatment agent and a patina treatment method capable of effectively removing the patina generated in a copper-based member with a single agent and effectively preventing the generation of patina. ..
The present invention also has a higher immediate effect on Legionella, an effect on bacteria and molds, a slime control effect and a bactericidal effect on a wider range of microorganisms, and an anticorrosive effect on copper. Further, it is characterized by providing a water treatment agent and a water treatment method that do not promote corrosion of iron-based members.

As a result of diligent studies to solve the above problems, the present inventors have found that dichloromethane can solve the above problems, and have completed the present invention.
That is, the gist of the present invention is as follows.

[1] A patina treatment agent that removes patina generated in a copper-based member or prevents the generation of patina, and is characterized by containing dichloromethane.

[2] The patina treatment agent according to [1], which contains dichloromethane and an azole-based copper anticorrosive agent.

[3] A patina treatment method for removing patina generated on a copper-based member or preventing patina generation, which comprises using dichloromethane.

[4] The patina treatment method according to [3], which comprises using dichloromethane and an azole-based copper anticorrosive agent.

[5] The method for treating copper-based members in contact with an aqueous system according to [3] or [4], which comprises adding dichloromethane to the aqueous system at a concentration of 10 to 100 mg / L. Patina processing method.

[6] The patina treatment method according to [5], wherein an azole-based anticorrosive agent for copper is further added to the water system so as to have a concentration of 0.1 to 10 mg / L.

[7] A water treatment agent for water-based slime control, sterilization, and anticorrosion that a copper-based member comes into contact with, which contains dichloroglycime.

[8] A water treatment method for performing slime control, sterilization, and anticorrosion of an aqueous system in contact with a copper-based member, which comprises adding dichloroglycime to the aqueous system.

[9] The water treatment method according to [8], which comprises adding dichloromethane to the water system at a concentration of 1 to 100 mg / L.

According to the patina treatment agent and the patina treatment method of the present invention, the patina generated in the copper-based member by one agent of dichloroglycime is effectively removed without adversely affecting the base material of the copper-based member and pitting corrosion. It is possible to prevent the reattachment of the removed patina and prevent the generation of new patina.

Further, according to the water treatment agent and the water treatment method of the present invention, the following effects are achieved.
1) It exhibits high bactericidal and mold-killing effects against a wide range of bacteria and molds in a concentration range that protects copper-based members and does not promote corrosion of iron-based members.
2) Shows high immediate effect at low concentration on Legionella.
3) The decomposition rate is high and does not adversely affect the post-stage processing.

It is a graph which shows the result of Experimental Example II-1. It is a graph which shows the result of Experimental Example II-2. It is a graph which shows the result of Experimental Example II-3. It is a graph which shows the result of Experimental Example II-4. It is a graph which shows the result of Experimental Example II-5. It is a graph which shows the result of Experimental Example II-6. It is a graph which shows the result of Experimental Example II-7. It is a graph which shows the result of Experimental Example II-8. It is a graph which shows the result of Experimental Example III.

Embodiments of the present invention will be described in detail below.

[Applicable water system]
The water system to which the green-blue treatment agent and the green-blue treatment method of the present invention and the water treatment agent and the water treatment method are applied may be any water system in which a copper-based member is present in contact with the water system, and is not particularly limited, but cooling. Examples include water systems, boiler water systems, scrubber water systems, paper pulp water systems, and film-treated water systems.
Of these, the present invention is particularly effectively applied to scrubber water systems because it can achieve both fast-acting properties and degradability in a system having a short residence time.

[Patina treatment agent / patina treatment method]
The patina treatment agent and the patina treatment method of the present invention are characterized by using dichloromethane.

In the patina treatment agent and the patina treatment method of the present invention, an azole-based copper anticorrosive agent may be used in combination with dichloroglioxime, and the combined use of the azole-based copper anticorrosive agent has a more excellent patina removing effect or patina generation prevention effect. Can be obtained.

In this case, examples of the azole-based copper anticorrosive agent used in combination with dichloroglycime include benzotriazole, tolyltriazole, mercaptobenzothiazole, aminotriazole and the like, and one of these may be used alone or 2 Seeds or more may be used together.

The concentration of dichloromethane added to the water system varies depending on the water quality of the water system and the presence or absence of the azole copper anticorrosive agent in combination, but it is preferably 10 to 100 mg / L, particularly about 20 to 60 mg / L. .. If the concentration of dichloromethane added is too small, the effect of removing and preventing the occurrence of patina due to the use of dichloromethane cannot be obtained, and if the concentration is too large, the effect tends to level off, and the solvent tends to level off. It is also not preferable in that the TOC and COD loads derived from the organic compound are increased in the wastewater treatment in the subsequent stage.

When the azole-based copper anticorrosive agent is used in combination, the concentration of the azole-based copper anticorrosive agent added is in the range of 0.1 to 10 mg / L, particularly 1 to 2 mg / L, thereby suppressing the amount of the drug used. Above, it is preferable to obtain a good addition effect.

To perform the patina treatment according to the present invention, the patina treatment agent of the present invention is added to the water system to be treated and circulated for a certain period of time. At this time, the contact time of dichloromethane is 30 to 60 minutes, but it may be longer than that.

When adding dichloromethane to the circulating water system to be treated, circulating water may or may not be newly prepared. Further, the circulating water system may be stopped and added, and then the circulation may be restarted, or the circulating water system may be added to the operating circulating water system. Further, it may be added continuously or intermittently. The same applies to the water treatment agent and the water treatment method described later.

Dichloroglycime is not affected by the water quality of the water to be treated, and is effective in any water system from pure water to tap water level and high salinity water system in which they are concentrated. Moreover, since the presence of a general anticorrosion and scale dispersant does not interfere with the effect of dichloromethane, these may be used in combination as necessary. Furthermore, since the presence of corrosive ions does not interfere with the effect of dichloroglycime, the patina treatment agent of the present invention is also effective for water systems in which corrosive ions are present.

In addition, since dichloromethane has anticorrosion ability against copper, it has little adverse effect on the base material, and dichloromethane has good degradability, and after the effect is exhibited, it decomposes quickly in the liquid, so blow water. There is also an advantage that the wastewater treatment is not adversely affected even if the wastewater is sent to the downstream wastewater treatment.

When the azole-based copper anticorrosive agent is used in combination, the dichloromethane and the azole-based copper anticorrosive agent may be added separately or at the same time. Further, it may be blended in one agent.

[Water treatment agent / water treatment method]
The water treatment agent and the water treatment method of the present invention are characterized by using dichloromethane.

The concentration of the dichloromethane added to the water system varies depending on the water quality of the water system and the like, but is preferably about 1 to 100 mg / L, particularly 1 to 5 mg / L. If the concentration of dichloromethane added is too low, sufficient slime control, bactericidal and anticorrosive effects due to the use of dichloromethane cannot be obtained, and if the concentration is too high, the effect tends to level off, and the solvent tends to level off. It is also not preferable in that the derived organic compound serves as a substrate for the organism in the target system and increases the TOC and COD loads of the wastewater treatment in the subsequent stage. Further, in order to effectively obtain the advantage of the present invention that a sufficient effect can be obtained by adding a low concentration of 10 mg / L or less, a high concentration addition is not preferable.

The water treatment agent of the present invention may be added continuously or intermittently. As explained in the section of the patina treatment agent and the patina treatment method described above, dichloroglycime depends on the water quality (purity and salt concentration) of the water system to be treated, the presence or absence of other chemicals, and the presence or absence of corrosive ions. Regardless, the effect can be effectively exerted.

The dichloroglycime may be used in combination with an anticorrosive agent for azole-based copper. Therefore, the water treatment agent of the present invention may contain dichloroglioxime and an anticorrosive agent for azole-based copper, and is used for azole-based copper. An even better anticorrosive effect on copper can be obtained by using an anticorrosive agent in combination.

In this case, examples of the azole-based copper anticorrosive agent used in combination with dichloroglycime include benzotriazole, tolyltriazole, mercaptobenzothiazole, and aminotriazole. One of these may be used alone, or two or more thereof may be used in combination.

When the azole-based copper anticorrosive agent is used in combination, the concentration of the azole-based copper anticorrosive agent added is in the range of 0.1 to 10 mg / L, particularly 1 to 2 mg / L, thereby suppressing the amount of the drug used. Above, it is preferable to obtain a good addition effect.

When the azole-based copper anticorrosive agent is used in combination, the dichloromethane and the azole-based copper anticorrosive agent may be added separately or at the same time. Further, it may be blended in one agent.

As mentioned above, dichloroglycime has good degradability, and dichloroglycime remaining after water treatment decomposes rapidly, so that it does not adversely affect the subsequent treatment, and in particular, it does not have an adverse effect on biological treatment. The water to which the water treatment agent of the present invention is added can be treated as wastewater without any problem by biological treatment or the like.

In the water treatment method of the present invention, other agents such as scale dispersant, other slime control agent, bactericide, and anticorrosive agent may be further added together with dichloroglycime, and therefore, the water treatment of the present invention. The agent may include these other agents along with the dichloroglycime.

Hereinafter, the present invention will be described in more detail with reference to Experimental Examples in place of Examples and Comparative Examples.

The water quality of the dechlorinated water of Nogi Town water used in the following experimental examples is as shown in Table 1 below.

In addition, NaCl was used as the chloride ion source added to the dechlorinated treated water of Nogi Town water for water quality adjustment, and Na ₂ SO ₄ was used as the sulfate ion source.

[Experimental Example I: Patina treatment]
<Experimental Example I-1>
Copper sulfate (blue-green) powder was added to pure water, and the chemicals shown in Table 2 were added to the concentrations shown in Table 2 (no chemicals were added in No. 4) to evaluate the ability to remove green-blue. An experiment was conducted.
The patina removing ability was evaluated by visually observing the color of each test solution after the addition of the chemical and the presence or absence of browning of the copper sulfate powder sediment. The results are shown in Table 2.

As is clear from Table 2, browning of the sediment did not occur when no drug was added and when carbhydrazide was added, but when dichloroglycime was added, browning was observed and the patina was modified. It was confirmed that it can be removed.

<Experimental Example I-2>
(Creation of patina test piece)
After scratching the degreased copper test piece (30 mm x 50 mm x 1 mm) with a cutter, add 1000 mg / L of chloride ion and sulfate ion to the dechlorinated water of Nogi Town water, and 0.5 mg of benzotriazole. / L and NaClO were _{placed in 1 L of a solution supplemented with 2} mg / La as Cl 2 as a residual chlorine concentration, and at 30 ° C., 150 r. p. A patina test piece was prepared by generating patina in the copper test piece by immersing the copper test piece under stirring for 7 days.

(Patina removal test)
In order to evaluate the effect in a corrosive environment, the above patina test piece was immersed in 300 mg / L of a test solution prepared by adding 500 mg / L of chloride ions and 500 mg / L of sulfate ions to dechlorinated treated water of Nogi Town water. The mixture was gently stirred with a stirrer at room temperature. 50 mg / L of dichloromethane was added thereto, and changes in the patina test piece and the test solution were visually observed over time. The results are shown in Table 3.

From Table 3, it can be seen that dichloromethane can be removed by modifying the patina generated on the copper surface with only one agent.

<Experimental Example I-3>
(Creation of patina test piece)
After scratching the degreased copper test piece (30 mm x 50 mm x 1 mm) with a cutter, add 1000 mg / L of chloride ion and sulfate ion to the dechlorinated water of Nogi Town water, respectively, and add NaClO to the residual chlorine concentration. In 1 L of a solution supplemented with 10 mg / Las Cl ₂ , at 30 ° C., 150 r. p. By immersing the copper test piece for 3 days with stirring of m, patina was generated in the copper test piece to prepare a patina test piece.

(Patina removal test)
In order to evaluate the effect in a corrosive environment as in Experimental Example I-2, the above was added to 300 mg / L of the test solution in which 500 mg / L of chloride ion and 500 mg / L of sulfate ion were added to the dechlorinated water of Nogi Town water. The patina test piece was soaked and gently stirred with a stirrer at room temperature. To this, dichloroglycime and / or benzotriazole was added so as to have the concentration shown in Table 4 (no drug was added in No. 5), and the mixture was treated with stirring for 60 minutes, and then the color of the patina test piece. The changes were visually observed and the copper concentration of the test solution was measured by atomic absorption spectrometry, and the results are shown in Table 4.

The following can be seen from Table 4.
1) No browning of patina was observed in the system to which dichloroglycime was not added, and it was considered that patina was not modified (Nos. 5 and 6).
2) When 50 mg / L of dichloromethane is added, the patina portion becomes brown to brown, and the base metal portion becomes orangeish brown (reddish brown) (Nos. 1 to 4).
3) When benzotriazole coexists, the patina part also becomes almost the same color as the base material, so it is considered that it is more homogenized (No. 2 to 4).
4) Even if benzotriazole was added, the copper concentration in the liquid did not increase unless dichloroglycime was added, but rather a tendency to decrease was observed (No. 6).
From the above, the synergistic effect on the patina removing effect is recognized by the combined use of dichloromethane and the anticorrosive agent for azole copper. Further, the elution of copper tends to be suppressed as compared with the case where no anticorrosive agent for azole copper is added, and from this point as well, it can be seen that the combined use of the anticorrosive agent for azole copper is effective.

[Experimental Example II: Slime control and anticorrosion]
<Experimental Example II-1>
Dichloroglycime and Cl-MIT (5-chloro-2-methyl-) were added to a test solution (pH 7.0 at the start of the test) in which 500 mg / L of chloride ion and 500 mg / L of sulfate ion were added to the dechlorinated water of Nogi Town water. 4-Isothiazolin-3-one) or NaClO was added at different concentrations, and a degreased copper test piece (30 mm × 50 mm × 1 mm) (area 31 cm ² ) was added to the solution at 30 ° C. for 146 r. p. It was immersed in m for 7 days under stirring. From the weight (mg) of the test piece before and after the test, ^{the corrosion weight loss (mdd) per 1 dm 2} test piece area per day was calculated, and the relationship between the chemical addition concentration and the corrosion weight loss was shown in FIGS. 1 (a) to 1 (c). It was shown to. In addition, the addition concentration of dichloromethane was 0 or 5 mg / L of RUN1 and 0, 2, 4 or 10 mg / L of RUN2, respectively.

As is clear from FIG. 1, Cl-MIT does not show sufficient corrosion resistance to copper and tends to promote corrosion at high concentrations (FIG. 1 (b)), and NaClO promotes copper corrosion. (FIG. 1 (c)), but it can be seen that dichloromethane exhibits anticorrosive properties against copper (FIG. 1 (a)).

<Experimental Example II-2>
In Experimental Example II-1, instead of the copper test piece, an iron test piece of the same size was used, and the same applies to the case where the dichloromethane was not added to the test solution and the case where the dichloromethane was added at 5 mg / L. An immersion test was performed to determine the amount of corrosion loss, and the results are shown in FIG.
From FIG. 2, it can be seen that dichloromethane does not promote iron corrosion.

<Experimental Example II-3>
To the test solution (pH 7.0 at the start of the test) in which 500 mg / L of chloride ion and 500 mg / L of sulfate ion were added to the dechlorinated water of Nogimachi water, 40 mg / L of 10% dichloroglioxime in DEGME (diethylene glycol monomethyl ether) solution was added. L (4 mg / L as dichloroglycime) or 40 mg / L of DEGME (diethylene glycol monomethyl ether) was added, and benzotriazole was added to this solution at different concentrations, and the degreased copper test piece (30 mm) was added. × 50 mm × 1 mm) (area 31 cm ² ) was added and 150 r. p. It was immersed in m for 7 days under stirring. Corrosion loss was determined from the weight of the test piece before and after the test in the same manner as in Experimental Example II-1, and the relationship with the benzotriazole concentration is shown in FIG.

From FIG. 3, it can be seen that the combined use of benzotriazole reduces the corrosiveness of copper as compared with dichloroglycime alone.
In particular, at a benzotriazole concentration of 1 mg / L, the corrosiveness was further reduced by the combined use of dichloroglycime as compared with benzotriazole alone.

<Experimental Example II-4>
_{Dichlorogrioxym 4 mg / L or NaClO 2} mg / Las Cl 2 was added to a test solution (pH 7.0 at the start of the test) in which 750 mg / L of chloride ion and 750 mg / L of sulfate ion were added to the dechlorinated water of Nogi Town water. , A degreased copper test piece (30 mm × 50 mm × 1 mm) (area 31 cm ² ) was added to the solution to which benzotriazole was added at different concentrations, and 150 r. p. It was immersed in m for 7 days under stirring. Corrosion loss was determined from the weight of the test piece before and after the test in the same manner as in Experimental Example II-1, and the relationship with the benzotriazole concentration is shown in FIG.

From FIG. 4, the NaClO-added system has insufficient anticorrosion property at a benzotriazole concentration of 0.1 mg / L, but the dichloroglycime-added system can improve the anticorrosion property, and even in the range where the effect of NaClO is insufficient. It can be seen that a sufficient effect can be obtained by the combined use of benzotriazole and dichloroglycime.

<Experimental Example II-5>
As shown below, a test was conducted to clarify the presence or absence of corrosion reduction when dibromonitroethanol (DBNE), which is corrosive, was used as an organic slime control agent and dichloroglycime was added thereto, and the results are shown in FIG. rice field.
A diethylene glycol solution of 75% dibromonitroethanol was added to a test solution (pH 8.0 at the start of the test) in which 500 mg / L of chloride ions and 500 mg / L of sulfate ions were added to the dechlorinated water of Nogimachi water, and the concentration of dibromonitroethanol added was high. After adding to 10 mg / L and adding a DEFME (diethylene glycol monomethyl ether) solution of 10% dichloroglycime so that the addition concentration of dichloroglycime is 1, 2, 3, 5 or 10 mg / L. (However, dichloroglycime was not added to the blank.), A degreased copper test piece (30 mm × 50 mm × 1 mm) (area 31 cm ² ) was added, and 150 r. At 30 ° C. p. It was immersed in m for 7 days under stirring. From the weight of the test piece before and after the test, the corrosion weight loss was determined in the same manner as in Experimental Example II-1 (addition 1).

Separately, instead of adding a diethylene glycol solution of 75% dibromonitroethanol and a DEGME (diethylene glycol monomethyl ether) solution of 10% dichloroglycime, a compounding drug in which dibromonitroethanol and dichloroglioxime were dissolved in DEGME was prepared in advance, and the combination drug was prepared. The same procedure as above was carried out except that the compounding chemical was added so that the dibromonitroethanol concentration was 10 mg / L and the dichloroglycime concentration was 2.7 mg / L, and the corrosion reduction of the copper test piece was determined (addition 2). ).

From FIG. 5, which shows the relationship between the concentration of dichloroglycime added and the reduction in corrosion, it can be seen that the corrosiveness of dibromonitroethanol can also be reduced by adding dichloroglycime. Further, it can be seen that the effect is the same whether it is pre-mixed or added separately.

<Experimental Example II-6>
A suspension of bacteria (Pseudomonas ptida) was added to 0.2 M phosphate buffer (pH 7), and at 30 ° C., 90 r. p. Shake at m, measure colony forming unit (CFU) for 0 hours, add dichloroglycime, Cl-MIT or NaClO at a predetermined concentration, and after 1 minute, 30 minutes and 24 hours under the same conditions. CFU was measured.
As a medium for CFU measurement, Peptone yeast extract medium was used and cultured at 30 ° C.
The results are shown in FIGS. 6 (a), 6 (b) and 6 (c).

As is clear from FIGS. 6 (a) to 6 (c), Cl-MIT has no immediate effect (FIG. 6 (b)), and NaClO is 99% or more in a short time by adding _{1 mg / La as Cl 2 or more.} Although it can be sterilized (FIG. 6 (c)), NaClO has a problem of corrosion. On the other hand, dichloromethane has a quicker effect than Cl-MIT when added at a low concentration, and exhibits 99% or more bactericidal activity within 1 hour (FIG. 6 (a)).

<Experimental Example II-7>
As follows, a comparative test of the bactericidal properties of dichloromethane and Cl-MIT against Legionella was conducted, and the results are shown in FIG.
Target bacteria: Legionella pneumophylla GIFU 9246
A660 0.1 diluted 10-fold with sterile tap water Evaluation drug: Dichloroglycime 1 mg / L
Cl-MIT 1 mg / L
Test method: The target bacteria were cultured on BCYEα agar medium, and the grown colonies were suspended in sterile water to prepare a bacterial solution having a 660 nm absorbance of 0.1. 1 mL of this bacterial solution was added to 9 mL of sterilized water to prepare a test solution.
The evaluation drug was added to the test solution in a volume of less than 100 μL so as to have a final concentration of 1 mg / L (no blank was added), and 90 r. p. m. I shook it.
Immediately after the addition of the evaluation drug, 1 hour and 24 hours later, 100 μL of a sample solution was collected from the test solution, smeared on BCYEα agar medium, and cultured at 37 ° C.
After 3-5 days, CFU was measured and converted per mL.

From FIG. 7, it can be seen that dichloromethane is excellent in the immediate effect of bactericidal activity against Legionella.

<Experimental Example II-8>
A suspension of Aspergillus niger was added to 0.2 M phosphate buffer (pH 7), and at 30 ° C., 90 r. p. Shake at m, measure colony forming unit (CFU) for 0 hours, add dichloroglycime, Cl-MIT or NaClO at a predetermined concentration, and after 1 minute, 30 minutes and 24 hours under the same conditions. CFU was measured.
A potato dextrose medium was used as a medium for CFU measurement, and the cells were cultured at 30 ° C.
The results are shown in FIGS. 8 (a), 8 (b) and 8 (c).

As is clear from FIGS. 8 (a) to 8 (c), Cl-MIT has no immediate effect (FIG. 8 (b)), and NaClO shows an immediate effect when _{2 mg / La as Cl 2 or more is added.} Has a problem of corrosion. On the other hand, dichloromethane shows a quicker effect than Cl-MIT with the addition of 4 mg / L, and shows 90% or more antifungal property within 1 hour (FIG. 8 (a)).

[Experimental Example III: Degradability of dichloromethane]
As shown below, dichloroglycime was dissolved in pure water, and the solution was analyzed by high performance liquid chromatography (HPLC) over time to determine the residual amount of dichloroglycime, and the results are shown in FIG. ..
500 mL of pure water was placed in a 1 L beaker equipped with a magnetic stirrer, a thermometer and a pH meter, and the mixture was vigorously stirred. 0.05 g of dichloromethane powder (corresponding to a concentration of 100 mg / L) was added thereto at one time. Over time, the reaction temperature and pH were measured, a fixed amount was sampled and analyzed by HPLC, and the peak area of dichloroglycime was measured. An ultraviolet detector (wavelength 220 nm) was used for detection. The reference 100 mg / L dichloroglioxime solution was prepared by measuring up dichloroglycime with an HPLC eluent. Then, the same amount as the reaction solution sample was analyzed by HPLC to measure the peak area of dichloromethane.
The residual rate (%) is a percentage of the value obtained by dividing the peak area of dichloromethane for each hour by the peak area of a solution of dichloromethane 100 mg / L.

As shown in FIG. 9, 95% of the dichloromethane is hydrolyzed in 15 minutes, so it can be seen that it is unlikely to adversely affect the subsequent treatment.

[Experimental Example IV: Disappearance of bactericidal effect of dichloromethane]
As the bacterial solution, the test bacterium (Ps. putida) was suspended in sterilized water to prepare a bacterial solution having an absorbance of 0.1 at 660 nm. 1 mL of this bacterial solution was added to 9 mL of 0.2 M phosphorus vinegar buffer (pH 7.0) to prepare a test solution.
After heating this test solution to 30 ° C., dichloromethane was added at the concentration shown in Table 5 (not added in No. 1), and 90r. At 30 ° C. p. After shaking at m for 15 minutes, CFU was measured and the sterilization rate was calculated. Further, the same bacterial solution was re-added, shaken for 15 minutes, and then CFU measurement was performed to calculate the sterilization rate. The results are shown in Table 5.

From Table 5, it can be seen that dichloromethane exhibited an excellent bactericidal effect after 15 minutes of contact, but the bactericidal effect was significantly reduced when the bacteria were re-added. From this result, it can be seen that the residual dichloromethane is unlikely to adversely affect the biological treatment in the subsequent stage.

Claims (2)

In patinated processing method of a copper-based member to remove the patina generated in copper-based member in contact with the water, a patina processing method using a dichloro glyoxime, a concentration of 10-100 mg / L dichloro glyoxime in the aqueous A patina treatment method characterized by being added in such a manner. The method for treating patina according to claim 1, wherein an azole-based anticorrosive agent for copper is further added to the water system so as to have a concentration of 0.1 to 10 mg / L.

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