JPS6075391A - Slime controlling method - Google Patents

Abstract

PURPOSE:To prevent effectively the deposition and generation of an aq. slime with a small amt. of chemicals to be added by adding jointly hydrazine and 2- mercaptopyridine-N-oxide zinc salt to industrial water, and utilizing the synergistic effect of both chemicals. CONSTITUTION:Hydrazine and 2-mercaptopyridine-oxide zinc salt in a (9:95)- (95:5)wt. ratio are added to the aq. system so that the total concn. of both chemicals may be regulated to about 1-100ppm. The slime difficulties due to the growth and propagation of microorganisms in the aq. system used in chemical factories as circulation water or in paper factories, etc. can be effectively prevented by this method. And the amt. of hydrazine to the added can be reduced.

Description

[Detailed description of the invention] This invention relates to a slime control method.

More specifically, the present invention relates to a method of treating slime produced by microorganisms in an aqueous system using hydrazine and 2-mercaptopyridine-N-oxide zinc salt.

In recent years, it is known that slime-related problems in various types of industrial water due to microbial contamination have been occurring frequently, and that this is bringing about divine evil. For example, slime forms in heat exchangers and wastewater cooling pipes for circulation cooling systems used in petrochemical plants and chemical factories, clogging the pipes and reducing cooling efficiency, or in paper manufacturing plants. Microorganisms generated in the white water form a muddy slime that peels off and mixes with the paper, causing the paper to break during the winding process, spots on the paper, unpleasant odors, and various other troubles. It is. As industrial disinfectants, even if they have strong disinfecting power, agents that are toxic to humans or cause environmental pollution by mixing with wastewater are avoided.

Hydrazine is known as a drug for preventing slime damage caused by microorganisms that grow and multiply in these various water systems. Hydrazine generally has the advantage of being weakly toxic and decomposing into non-toxic water and nitrogen gas, but on the other hand, it is easily decomposed in open water that is constantly in contact with air, so large amounts of hydrazine must be used. The cost is too high to be practical.

The inventors of this invention conducted extensive research with the aim of developing a slime control method that takes advantage of the characteristics of hydrazine and is even less toxic.As a result, the inventors of this invention used a combination of hydrazine and a zinc salt of 2-mercaptopyridine-N-oxide. This allows the amount of hydrazine added to be reduced to about 1/l compared to when using it alone.
This invention was completed by discovering that a remarkable synergistic effect can be achieved by reducing the ratio by a factor of 20 to 1/200.

2-Mercaptopyridine-N-oxide zinc salt, which is one of the active ingredients of this invention, is a compound well known under the trade name "zinc pyrithione" and is incorporated into anti-dandruff shampoos, conditioners, and the like. In general, metal derivatives (metal salts) of 2-mercaptopyridine-N-oxide are known to have antibacterial and antifungal activities, but as slime control agents added to aqueous systems, water-insoluble 2-mercaptopyridine-N-oxide is generally used as a slime control agent.
-Mercaptopyridine-N-oxide Water-soluble alkali metal salts were easier to handle than lead salts and had better effects. (Japanese Unexamined Patent Publication No. 52-83934) Furthermore, the use of hydrazine and other drugs in combination is, for example, disclosed in Japanese Unexamined Patent Publication No. 57-83934.
This is known as JP-A-212107 and JP-A-58-67610. However, the effects of these combinations,
Furthermore, it is surprising that the effect of the combination of the present invention is significantly better than that of the combination of hydrazine and a known slime control agent.

The hydrazine used in this invention may be in the form of hydrazine as it is, but since it is inconvenient to handle, inorganic acids such as hydrazine hydrate, hydrazine hydrochloride, hydrazine sulfate, hydrazine nitrate, hydrazine carbonate, phosphorous +6 hydrazine, hydrazine sulfamate, etc. salts of hydrazine, organic acid salts of hydrazine such as hydrazine acetate, hydrazine citrate, and hydrazine adipic acid, and hydrazine derivatives such as phenylhydrazine, hydroxyhydrazine, and monomethylhydrazine.

In this invention, the appropriate blending ratio for the two active ingredients to exhibit a synergistic effect compared to when they are used alone is hydrazine (in terms of IJ2H4) and 2-mercaptopyridine-N-oxide zinc salt at 5: The ratio is 95 to 95:5, preferably 10:90 to 85:i5. Furthermore, the amount of addition according to the method of this invention is such that the synergistic effects are expressed even when the two active ingredients are added to the process water of the paper manufacturing process or industrial cooling water at the most preferable ratio when the concentration in the system is usually less than 11) pm. Its bactericidal and bacteriostatic powers are insufficient for practical purposes, and even if it is added in excess of 100 ppm, there is no particular advantage in terms of effectiveness compared to adding less than 100 ppm, and it is not economical. According to this invention, the value is 1 to 1100.
By adding ppm, preferably 5 to 30'ppm, the number of harmful microorganisms can be reduced to 10 or less.

When adding hydrazine and 2-mercaptopyridine-N-oxide zinc salt to the aqueous system in the method of this invention,
Both drugs may be mixed in advance and added, or each drug may be added separately.

Furthermore, the mode of addition may be continuous administration or intermittent administration. Note that when both drugs are mixed in advance, 2-mercaptopyridine-N-oxide zinc salt is not soluble in water by itself, so it is dispersed using an appropriate dispersant (sodium silicate, sodium phosphate, etc.). It is usually preferred to subsequently formulate with hydrazine.

Therefore, the present invention also provides a slime control agent containing hydrazine and 2-mercaptopyridine-N-oxide zinc salt as active ingredients.

Water systems to which the slime control method of the present invention can be applied include, for example, acid/neutral papermaking white water systems in which paper is made in acid/neutral conditions, and 1) alkaline papermaking white water systems with H7.5 to 10. It shows excellent effects, especially in alkaline papermaking white water systems.

Thus, by using hydrazine and 2-mercaptopyridine-N-oxide zinc salt in combination, this invention can economically and efficiently control the adhesion and generation of aqueous slime, and has extremely industrial value. This is a good method.

Next, a synergistic effect test example and examples of two components used to complete this invention will be explained.

Pseudornonas Aerginos test example 1
bactericidal effect against Pseudomonas aerginosa 7144)
4 was planted in a bouillon medium and cultured at 37°C for 15 hours. After that, it was planted in a new bouillon medium, and when the absorbance reached 0.6, the culture solution was diluted 100 times with sterile water, and NaSO3 was added to a concentration of 1100 pp in a backward-shaped test tube. 10 rnP was dispensed. A predetermined drug was added to each sample and the samples were brought into contact with each other for 4 hours using a vibrator. After this, plant in bouillon medium,
The cells were cultured in a furan vessel at 37°C for 48 hours, and the number of viable bacteria per 1 d of culture solution was measured. The results are shown in Table 'fA1.

Test Example 2 (Synergistic effect at each ratio of hydrazine and 2-mercaptopyridine-N-oxide zinc salt) According to the procedure of Test Example 1, hydrated hydrazine (N2Ha・N20) and 2-mercaptopyridine-N-oxide zinc salt The bactericidal effect was tested for various ratios of (Number of viable bacteria 7.OX106(I
M/ml! J The results are shown in Table 2.

Table 2 Table 2 (Continued) (Considerations) 2-Mercaptopyridine-N-oxide zinc salt alone requires 40 I) pm to reduce the number of formation j to 10 (pieces/mf!) or less, and hydrazine 640 alone
ppm is required. In comparison, the present invention contains 3.2 ppm of hydrazine (1/200 of the amount when used alone) and 10 ppm of 2-mercaptopyridine-N-oxide.
By using M (174 measures when used alone) in combination, the number of viable bacteria can be reduced to 10 (cells/ml) or less. (See Test No. 8) Similarly, in Test No. 11, by using 1/100 of the amount of hydrazine alone and the amount of 2-mercaptopyridine-N-oxide zinc salt 115.3, and in Test No. 19. are 1/21 when used alone.
By using 3 and 1/16 amounts together, the number of viable bacteria can be reduced to 10 (
It is understood that a remarkable synergistic effect is being exerted. Figure 1 shows the test results plotted with the vertical axis representing the total addition i (ppm) of the drug that reduces the number of viable bacteria to 10 (counts/rd) or less and the horizontal axis representing the proportion (%) of N2H4 in the total amount added. As shown in the figure. (The number in the diagram is the second
Indicates the test number in the table. ) From this figure, it is understood that a remarkable synergistic effect is exhibited by the combined use of hydrazine and 2-mercaptopyridine-N-oxide zinc salt in various ratios. The preferred ratio of both is
Hydrazine: 5:95 to 95:5 as 2-mercaptopyridine-N-oxide zinc salt, more preferably 1
It can be seen that the ratio is 0:90 to 85:15.

Example 1 (including comparative examples) (Effect of combined use of hydrazine and known disinfectants on on-site white water) M/C alkaline paper machine No. 4 m/c Save All white water (pH 7.4, viable bacterial count 2.0 x 106 pieces/m were collected and dispensed into L-shaped test tubes, and the prescribed chemicals were added to each sample and left in contact for 5 hours in a shaker, then planted in a bouillon medium. 4 in a flan oven at 37°C.
After culturing for 8 hours, the number of viable bacteria per 1 d of culture solution was measured. The results are shown in Table 3.

Examples 2-5 Following the procedure of Example 1, the bactericidal effects of hydrazine hydrate and 2-mercaptopyridine-N-oxide with E-lead salt were evaluated on different papermaking white waters collected from each paper mill.
I have determined. The results are summarized in the fourth section along with the water quality and image quality of white water.
Shown in the table.

Example 6 According to step 11ffi of Example 1, the bactericidal effect of hydrated hydrazine and 2-mercaptopyridine-N-oxide zinc salt was measured on cooling water collected from a certain petrochemical factory. The results are shown in Table 5 along with the quality of the cooling water. (However, in this case, the contact time in the shaker ψN was 4 hours.) As described above, the effect of the combined use of hydrazine and 2-mercaptopyridine-N-oxide zinc salt in this invention can be seen in general cooling water systems, acids and It shows a good synergistic effect not only in neutral paper-making white water systems, but also in alkaline paper-making white water systems, where slime control is generally very difficult, and the generation of slime, which was a problem in conventional industrial water, has been drastically reduced.
The system was able to operate without any problems and fully demonstrated its value as a slime control method. In comparison with the effects of other known slime control methods, the effects of the present invention are even more excellent in alkaline papermaking white water systems.

It is.

Claims (1)

[Claims] 1. A method for controlling slime, which comprises adding hydrazine and 2-mercaptopyridine-N-oxide zinc salt to an aqueous system to control slime. 2. The slime control method according to claim 1, wherein the ratio of hydrazine to 2-mercaptopyridine-N-oxide zinc salt is 5:95 to 95:5 parts by weight. 3. The slime control method according to claim 2, wherein the addition ratio of hydrazine and 2-mercaptopyridine-N-oxide zinc salt is 10:90 to 85:15 parts (U part). 4. Hydrazine and 2- mercaptopyridine-N-oxide zinc salt in an aqueous system at a total concentration of 1 to 1 oop.
The slime control method according to any one of claims 1 to 3, which comprises adding PM.