JP2002086155A - Sterilization method of water system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sterilization method of a sterilizing object water system by producing and using hypobromous acid and/or hypoiodous acid inexpensively, safely, and simply. SOLUTION: (A) Peracetic acid or substance enabling production of hydrogen peroxide or a peracetic acid aqueous solution or a hydrogen peroxide aqueous solution and (B) a substance enabling feed of bromide ions and/or iodide ions or an aqueous solution containing bromide ions and/or iodide ions, are mixed in a sterilizing object water system or (A) a peracetic aqueous solution or a hydrogen peroxide aqueous solution is preliminarily mixed with (B) an aqueous solution containing bromide ions and/or iodide ions, and the obtained antiseptic- containing mixed solution is added to the sterilizing object water system to sterilize the water system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sterilization method suitable for sterilization of various water systems, particularly cooling water systems, and sterilization of medical equipment.

[0002]

2. Description of the Related Art Conventionally, chlorine agents such as hypochlorous acid have been used.
Widely used as a safe and reliable disinfectant and disinfectant. Specifically, hypochlorous acid is used for disinfection and sterilization of water systems such as water and sewage, various industrial wastewaters, and pools. In addition, an aqueous solution of hypochlorous acid is also used as a disinfectant or sterilizing liquid for disinfecting or sterilizing medical equipment.

[0003] However, the bactericidal activity of hypochlorous acid (HOCl) depends on the pH of the added aqueous system. In an acidic aqueous system, hypochlorous acid exhibits excellent bactericidal activity, but the pH is 6.5. hypochlorous acid under neutral to alkaline aqueous exceed the hypochlorite ion (OCl ^-) are dissociated into, bactericidal power is lowered, in particular a pH of 8 or more water the sterilizing power is rapidly reduced . In addition, even in a small amount, due to the presence of the chlorine agent, iron, copper, aluminum,
There is also a concern about corrosion of metal materials such as stainless steel.

Therefore, hypobromous acid (HOBr) has been proposed as a bactericide whose bactericidal power is not affected by the pH value and which does not easily cause a corrosion problem with metal materials. Hypobromite is obtained by reacting an aqueous solution of a strong base with bromine, but is chemically unstable and cannot be tolerated for long-term storage. Therefore, ClO ^- containing hypochlorite and Br ^- containing bromide salt (e.g., sodium bromide) are mixed just prior to addition to the aqueous system, a method of adding to the aqueous system (Japanese Patent No. 2716126 ), And a method of injecting ozone into water containing bromide ions to convert 80% or more of the bromide ions into hypobromite, and then injecting this into a water system having a pH of 8 to 9 (Japanese Patent Publication No. 7-57721). Has been proposed.

However, these methods have a problem that unreacted hypochlorite remains in an aqueous system, and that a desired bactericidal power cannot be obtained, and a cost problem that an expensive ozone generator is required. there were.

[0006]

SUMMARY OF THE INVENTION The present invention provides a low cost,
An object of the present invention is to provide a method for safely and easily producing hypobromous acid and / or hypoiodic acid, and thereby disinfecting a water system to be sterilized.

[0007]

Means for Solving the Problems The inventors of the present invention provide:
In disinfecting the aqueous system by allowing hypobromite and / or hypoiodite to exist in the water system to be sterilized, a substance capable of producing peracetic acid or hydrogen peroxide or an aqueous solution of peracetic acid or hydrogen peroxide, and bromine ions and / Or a substance capable of supplying iodine ions or bromine ions and / or
Alternatively, an aqueous solution containing iodine ions is mixed in an aqueous system to be sterilized, or an aqueous solution of peracetic acid or hydrogen peroxide and an aqueous solution containing bromine ions and / or iodine ions are mixed in advance, and the resulting solution is obtained. The inventors have found that hypobromous acid and / or hypoiodic acid obtained by adding a bactericide-containing mixture to an aqueous system to be sterilized exhibit an effective bactericidal effect in aqueous systems, and have completed the present invention. .

Thus, according to the present invention, it is possible to supply (A) a substance capable of producing peracetic acid or hydrogen peroxide or an aqueous solution of peracetic acid or hydrogen peroxide, and (B) a bromine ion and / or an iodine ion. An aqueous sterilization method is provided, comprising mixing a substance or an aqueous solution containing bromine ions and / or iodine ions in an aqueous system to be sterilized, and sterilizing the aqueous system.

Further, according to the present invention, (A) an aqueous solution of peracetic acid or an aqueous solution of hydrogen peroxide and (B) an aqueous solution containing bromine ions and / or iodine ions are mixed in advance, and the resulting fungicide-containing solution is obtained. An aqueous sterilization method is provided, wherein the mixed solution is added to an aqueous system to be sterilized to sterilize the aqueous system. In the following description, “%” means “% by weight” unless otherwise specified.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION As a substance capable of producing peracetic acid used in the present invention, for example, "BUSAN 1000" manufactured by Bachman Laboratory Co., Ltd. sold by Nagase Sangyo Co., Ltd. is exemplified. Can be
This Beusan 1000 is a powder formulation that generates peracetic acid when dissolved in water, and is known as a general-purpose disinfectant. When this is dissolved in water at a concentration of 1 g / l, 350
Peracetic acid of about mg / l is produced.

The aqueous solution of peracetic acid is obtained by dissolving peracetic acid or a substance capable of producing peracetic acid in water so that the concentration of peracetic acid becomes a desired concentration. As the peracetic acid, those commercially available for industrial use can be usually used. For example, peracetic acid 6%, acetic acid 32%, water 54%
And 8% hydrogen peroxide, 32% peracetic acid, 4% acetic acid and 64% water, and 2% peracetic acid.
One having a composition of 6%, 54% of acetic acid and 20% of water is exemplified.

The substance capable of producing hydrogen peroxide used in the present invention includes, for example, inorganic peracids such as perboric acid, percarbonate and peroxysulfate and salts thereof (for example,
Sodium percarbonate) and the like.

The aqueous hydrogen peroxide solution is obtained by dissolving hydrogen peroxide or a substance capable of producing hydrogen peroxide in water so that the hydrogen peroxide concentration becomes a desired concentration. As the hydrogen peroxide, an aqueous solution of hydrogen peroxide having a concentration of 3 to 60%, which is generally commercially available for industrial use, can be used.

Further, hydrogen peroxide generated in water can be used. Examples of the method of generating hydrogen peroxide in water include electrochemical decomposition of water or an alkaline solution, irradiation of water with high energy rays such as ultraviolet rays and radiation, or aquatic organisms [eg, Poecillia vellifere].
(Oryzidae).

The bromine ion and / or bromine ion used in the present invention
Alternatively, examples of the substance that can supply iodine ions include bromides and iodides of alkali metals such as sodium bromide, potassium bromide, sodium iodide, and potassium iodide.

The aqueous solution containing bromine ions and / or iodine ions may be a substance capable of supplying bromine ions or iodine ions, that is, a substance capable of dissociating ions in water to produce bromine ions or iodine ions. Alternatively, it is obtained by dissolving hydrobromic acid or hydroiodic acid in water to a desired concentration.

The above-mentioned alkali metal bromides or iodides are all industrially available at low cost and are particularly preferred because of their high solubility in water. An aqueous solution obtained by dissolving them in water is chemically stable and long-lasting. Can be stored for a long period of time. Therefore, these aqueous solutions can be stored in a storage tank and the required amount can be used as needed.

Also, hydrobromic acid and hydroiodic acid are
A commercially available aqueous solution of hydrogen bromide (eg, hydrobromic acid, about 47%) or an aqueous solution of hydrogen iodide (eg, hydroiodic acid, about 58%) is mixed with water to a desired concentration. It can be used after dilution.

In the present invention, the above component (A) of peracetic acid or hydrogen peroxide and the component (B) of bromine ion and / or iodine ion are mixed in an aqueous system to be sterilized or mixed in advance. Then, hypobromous acid and / or hypoiodic acid obtained by adding the resulting product to the water system to be sterilized is used as a sterilizing active ingredient. The combination of these components (A) and (B) is not particularly limited, but a combination of an aqueous solution of peracetic acid and an aqueous solution of an alkali metal bromide or iodide, and an aqueous solution of hydrogen peroxide and an aqueous solution of hydrobromic acid or iodine Combinations with hydrofluoric acid are particularly preferred.

In the case of the above combination, the molar concentration of peracetic acid in the aqueous solution of peracetic acid is from 0.000074 to 1
mol / l, preferably 0.01 to 0.5 mol / l, more preferably 0.05 to 0.1 mol / l.

The molar concentration of bromide and / or iodide in an aqueous solution of an alkali metal bromide and / or iodide is 0.00016 to 1 mol / l, preferably 0.05 to 0.5 mol / l, more preferably Is 0.05
０．１0.1 mol / l.

When the molar concentration of each aqueous solution is in the above range, it is preferable in terms of handling properties, safety and solubility of each aqueous solution, and reaction time of peracetic acid with bromine ions and / or iodine ions. The molar ratio of peracetic acid to the bromide and / or iodide of the alkali metal is 1: 1 to 1
About 1:10 is preferred.

When an aqueous solution of peracetic acid is mixed with an aqueous solution of an alkali metal bromide and / or iodide, acetic acid and hypobromous acid and / or hypoiodic acid are produced according to the following reaction formula. CH ₃ COOOH + X ⁻ + H ⁺ → CH ₃ COOH + HXO (where X represents Br or I) When the molar concentration of the aqueous solution of peracetic acid is relatively low, the molar concentration of the bromide and / or iodide of the alkali metal is increased. If it is set, the generation reaction of hypobromous acid and / or hypoiodic acid proceeds efficiently.

The above reaction need not be completed to 100%, and the object of the present invention is achieved if a sterilizing effective amount of hypobromous acid and / or hypoiodic acid is present in the water system to be sterilized. The unreacted peracetic acid itself is an effective bactericide, and the bactericidal effect is exhibited in combination with the bactericidal action of hypobromite and / or hypoiodic acid as reaction products. Excessive addition of peracetic acid is one of the preferred embodiments of the present invention. However, adding 25 mg / l or more of peracetic acid to the water system to be sterilized may cause or induce corrosion of the iron-based metal of the structure containing the water system.
It is desirable to avoid. In addition, high concentrations of peracetic acid are dangerous because they are dangerous to handle and are easily decomposed.

In the case of the above combination, the molar concentration of hydrogen peroxide in the aqueous hydrogen peroxide solution used is
0.01 to 10 mol / l, preferably 0.03 to 5 mol / l,
More preferably, it is 0.03 to 3 mol / l.

The molar concentration of hydrogen bromide and / or hydrogen iodide in hydrobromic acid and / or hydroiodic acid is 0.01 to 30 mol / l, preferably 0.1 to 1 mol / l.
It is 5 mol / l, more preferably 0.1 to 10 mol / l.

When the molar concentration of each aqueous solution is within the above range, it is preferable in terms of handling properties, safety and solubility of each aqueous solution, and the reaction time between hydrogen peroxide and bromine ions and / or iodine ions. The molar ratio of hydrogen peroxide to hydrogen bromide and / or hydrogen iodide is from 1: 1 to 1:
About 5 is preferable.

When an aqueous solution of hydrogen peroxide is mixed with hydrobromic acid and / or hydroiodic acid, water and hypobromous acid and / or hypoiodic acid are produced according to the following reaction formula. H ₂ O ₂ + XH → H ₂ O + HXO (where X represents Br or I) When the molar concentration of the aqueous hydrogen peroxide solution is relatively low, the molar concentration of hydrogen bromide and / or hydrogen iodide is increased. If it is set, the generation reaction of hypobromous acid and / or hypoiodic acid proceeds efficiently.

If the sterilizing effective amount of hypobromite and / or hypoiodic acid is present in the water system to be sterilized, the object of the present invention is achieved, but unreacted hydrogen peroxide is produced by the reaction product. May be decomposed or cause corrosion of the iron-based metal of the structure containing the aqueous system. Therefore, it is preferable to use hydrobromic acid and / or hydroiodic acid in excess with respect to hydrogen peroxide.

The reaction between peracetic acid and an alkali metal bromide and / or iodide, and the reaction between hydrogen peroxide and hydrogen bromide and / or hydrogen iodide proceed in a relatively short time. For example, hypobromous acid generated when an aqueous solution of peracetic acid is mixed with an alkali metal bromide and / or iodide, or when hydrogen peroxide and hydrobromic acid and / or hydroiodic acid are mixed, And / or the concentration of hypoiodic acid increases rapidly, reaching a maximum after about 5 minutes in the former and about 3 minutes in the latter, after which the hypobromite and / or hypoiodic acid gradually decomposes. Since the sterilizing effect tends to be attenuated, it is preferable to mix both aqueous solutions in the aqueous system to be sterilized or to mix both aqueous solutions in advance just before adding to the aqueous system to be sterilized.

In carrying out the method of the present invention, an aqueous solution of peracetic acid or an aqueous solution of hydrogen peroxide and an aqueous solution containing bromine ions and / or iodine ions are mixed in dedicated mixing tanks, respectively, and the resulting mixed solution is mixed. The liquid may be added to the water system to be sterilized, but it is usually convenient to mix and add the water using an existing narrow pipe provided for adding the drug to the water system to be sterilized. That is, an aqueous solution of peracetic acid or an aqueous solution of hydrogen peroxide and an aqueous solution containing bromide ions and / or iodine ions are separately injected into the existing narrow pipe, and the two aqueous solutions are combined and mixed on the way to the water system to be sterilized. Then, it is convenient to add it directly to the water system to be sterilized.

Further, a substance capable of producing peracetic acid or hydrogen peroxide and a substance capable of supplying bromide ion and / or iodine ion are rapidly dissolved in the water to be sterilized, and the produced peracetic acid or hydrogen peroxide; Bromine ions and / or
Alternatively, if hypobromous acid and / or hypoiodic acid are produced by reacting promptly with iodine ions, supply a substance capable of producing peracetic acid or hydrogen peroxide, bromine ions and / or iodine ions. The substance that can be added may be added in powder form to the aqueous system to be sterilized. For example, in the case of a combination of a powder that generates peracetic acid (Byusan 1000) and a sodium bromide powder, this method can be adopted.

When each substance is used in the form of a powder as described above, both may be separately added to the aqueous system to be sterilized. It can also be used as a tablet prepared by press molding using a binder. The mixing ratio of each substance may be appropriately set so that the desired concentration of hypobromous acid and / or hypoiodic acid is generated in the water system to be sterilized. Thus, if the substance to be handled is a solid, it is advantageous in terms of transportation, storage, workability, and the like.

In the present invention, the effective concentration of hypobromous acid and / or hypoiodic acid in the water system to be sterilized is:
Type and number of microorganisms to be sterilized, temperature of water system to be sterilized, p
Although it depends on H, nutrient sources and / or the presence of organic matter, it is usually 0.01 to 2 mg / l, preferably 0.5 to 1 m in terms of effective chlorine concentration with respect to the water to be sterilized.
g / l. When the concentration of hypobromous acid and / or hypoiodic acid in the water system to be sterilized is within the above range, an excellent sterilization effect can be obtained without adversely affecting the metal material of the structure containing the water system.

In the sterilization method of the present invention, known sterilizing components and anticorrosive components can be used in combination as long as the effects of the present invention are not impaired. Such known fungicides include:
2-nitro-2-bromo-1,3-propanediol,
Organic bromine compounds such as 2,2-dibromo-2-nitroethanol and 2,2-dibromo-3-nitrilopropionamide are exemplified. In addition, as a known anticorrosive,
Phosphates such as sodium phosphate and potassium phosphate,
Sodium 1,1-hydroxyethanediphosphonate,
Examples thereof include phosphonates such as 1,1-hydroxyethanediphosphonic acid.

The water system to be sterilized in the sterilization method of the present invention includes cooling water in various factories such as a petrochemical factory, a chemical factory, and a thermal / nuclear power plant using industrial water, seawater, lake water, river water, and the like. Systems, washing water systems, wastewater (wastewater) treatment systems, papermaking process water systems in paper and pulp mills, and pulp slurries.

The sterilization method of the present invention can be applied to the disinfection and sterilization of various instruments such as various industrial products and medical equipment. Specifically, a mixed solution of an aqueous solution of peracetic acid or an aqueous solution of hydrogen peroxide and an aqueous solution containing bromine ions and / or iodine ions is used as a disinfectant or disinfectant, and various industrial products or medical equipment are immersed therein. By doing so, disinfection and sterilization of the device are performed.

[0038]

EXAMPLES The present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.

Preparation of Mixture Preparation Example 1 Peracetic acid (manufactured by Aldrich, reagent, acetic acid dilution 32% by weight)
Solution) and sodium bromide (Kishida Chemical Co., Ltd., special grade reagent) or potassium iodide (Kishida Chemical Co., Ltd.)
Using a special grade reagent), a mixed solution was prepared. First, peracetic acid is diluted with ion-exchanged water, and the molar concentration of peracetic acid is 1 mol / mol.
1, 0.1 mol / l and 0.01 mol / l aqueous solution of peracetic acid were prepared. Further, sodium bromide was dissolved in ion-exchanged water to prepare aqueous sodium bromide solutions having a bromide ion molar concentration of 1 mol / l, 0.1 mol / l and 0.01 mol / l.
Further, potassium iodide was dissolved in ion-exchanged water to prepare an aqueous solution of potassium iodide having a molar concentration of iodide ions of 0.1 mol / l.

An aqueous solution of peracetic acid and an aqueous solution of sodium bromide or potassium iodide having a molar concentration and a volume shown in Table 1 were placed in a test tube and mixed for 5 minutes, and peracetic acid was mixed with sodium bromide or potassium iodide. The mixture was reacted to obtain a mixed solution. Next, sodium hydroxide was added to the mixture to adjust the mixture to be alkaline (about pH 10). The obtained mixture was added to 1 liter of ion-exchanged water, and this was used as test water.

Preparation Example 2 A mixture was prepared using 35% hydrogen peroxide (food additive, manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 47% hydrobromic acid (special grade reagent, manufactured by Kishida Chemical Co., Ltd.). First, 35% hydrogen peroxide was diluted with ion-exchanged water to prepare a hydrogen peroxide aqueous solution having a molar concentration shown in Table 2. Further, 47% hydrobromic acid was diluted with ion-exchanged water to prepare hydrobromic acid having a molar concentration shown in Table 2.

An aqueous solution of hydrogen peroxide having the molar concentration and volume shown in Table 2 and hydrobromic acid were placed in a test tube, mixed for 3 minutes, and reacted with hydrogen peroxide and hydrobromic acid. I got Next, the obtained mixture was added to 1 liter of ion-exchanged water, and this was used as test water. The pH of the test solution is 7.
It was in the range of 1 to 8.2.

Measurement of Hypobromite Concentration in Test Water 1 The concentration of hypobromite or hypoiodite in the test water of Preparation Example 1 (in terms of available chlorine concentration) was measured by the ortho-tolidine method. For comparison, the effective chlorine concentration was measured in the same manner as described above for the test water containing only the aqueous solution of peracetic acid or the aqueous solution of sodium bromide. The results obtained are shown in Table 1 together with the molarity and volume of the aqueous solution used.

[0044]

[Table 1]

0.1 ml of a 1 mol / l aqueous solution of peracetic acid and 1 mol / l
In the case of a mixture with 0.1 ml of an aqueous sodium bromide solution, a strong halogen odor was generated during the mixing, and the mixture turned yellow. The effective chlorine concentration of the corresponding test water was 0.2 mgCl / l (No. 1). In a mixture of 1 ml of a 0.1 mol / l peracetic acid aqueous solution and 1 ml of a 0.1 mol / l sodium bromide aqueous solution, a slight halogen odor was generated during the mixing, and the mixture turned yellow. The effective chlorine concentration of the corresponding test water is 1.0
mgCl / l (No. 2). From the above results, it can be seen that even when peracetic acid and sodium bromide are reacted at a molar ratio of 1: 1, when the respective solutions are diluted, the reaction hardly occurs.

The effective chlorine concentration of test water using a mixture prepared by combining various concentrations and volumes of aqueous peracetic acid and aqueous sodium bromide was 0.1 to 1.0 mgCl / l (No. 3-8). 0.1 mol / l peracetic acid aqueous solution 1
ml and 0.1 mol / l instead of aqueous sodium bromide solution
The effective chlorine concentration of the test water using a mixture prepared from 1 ml of an aqueous potassium iodide solution could not be measured by the ortho-tolidine method, but the test water turned blue by adding the starch solution (No. .9).

When only 1 ml of 1 mol / l aqueous solution of peracetic acid and 1 ml of 1 mol / l aqueous sodium bromide were used as test water, no effective chlorine was detected (N
o. 10 and no. 11). This indicates that hypobromous acid is not generated only with peracetic acid or bromine ion alone.

No. The result of No. 9 shows that the reaction with peracetic acid proceeds not only with bromine ions but also with iodine ions. Further, experiments show that when the molar ratio of peracetic acid to bromine ion is 1: 1 to 1:10, a reaction for producing hypobromous acid occurs.

Measurement 2 of hypobromite concentration in test water Hypobromite (in terms of available chlorine concentration) in test water of Preparation Example 2
Was measured by the ortho-tolidine method. For comparison, the effective chlorine concentration was measured in the same manner as above for the test water containing only the aqueous hydrogen peroxide solution or hydrobromic acid. The results obtained are shown in Table 2 together with the molarity and volume of the aqueous solution used.

[0050]

[Table 2]

The effective chlorine concentration of test water using a mixture prepared by combining various concentrations and volumes of an aqueous solution of hydrogen peroxide and hydrobromic acid was 0.1 to 1.0 mgCl / l (No. .12 to 19).

3.0 mol / l hydrogen peroxide aqueous solution 0.187
ml and 8.6 mol / l hydrobromic acid 0.100 m
When only 1 was used as test water, no available chlorine was detected (Nos. 20 and 21). This indicates that hypobromite is not generated only by hydrogen peroxide or bromine ion.

Experiments also show that when the molar ratio between hydrogen peroxide and bromine ions is about 1: 3, a reaction for producing hypobromous acid occurs.

Test for confirming the bactericidal effect of a mixture of an aqueous solution of peracetic acid and an aqueous solution of sodium bromide A solution containing gram-positive bacteria and gram-negative bacteria was prepared (initial bacterial count: 4.3 × 10 ⁷ cells / ml). 1 liter of the obtained solution was collected in a 1 liter beaker. 2.5%
1 ml of an aqueous solution of peracetic acid (Solution A) and 1 ml of a 1.0% aqueous solution of sodium bromide (Solution B) were mixed and reacted for 3 minutes, and the mixture was added to a beaker. One hour, three hours, and six hours after the addition of the mixed solution, a simple cultivation medium easiness cultivation medium was immersed in a beaker solution, and the number of bacteria in the solution was simply measured. After 24 hours, the number of bacteria in the solution was measured by a standard agar medium method.

In addition, the number of bacteria was measured in the same manner as described above for the solution to which neither the solution A nor the solution B was added (blank) or the solution to which either the solution A or the solution B was added. The results obtained are shown in Table 3 and FIG. In the drawing, indicates a blank, indicates only the solution A, indicates only the solution B, and indicates a mixture of the solution A and the solution B. FIG. 1 also shows the results of measurement of the initial number of bacteria in a solution containing Gram-positive bacteria and Gram-negative bacteria.

[0056]

[Table 3]

From Table 3 and FIG. 1, it can be seen that the mixture of the solution A and the solution B, that is, the mixture of the aqueous solution of peracetic acid and the aqueous solution of sodium bromide has an excellent sterilizing effect.

Test for Confirming Bactericidal Effect of Mixed Solution of Hydrogen Peroxide Aqueous Solution and Hydrobromic Acid A solution shown in Table 4 was prepared (initial number of bacteria: 1 × 10 ⁷ cells / m 2).
l) 1 liter of the resulting solution was collected in a 1 liter beaker. A mixed solution (No. 12 to 10) in which an aqueous solution of hydrogen peroxide and hydrobromic acid shown in Table 2 were mixed and reacted for 3 minutes
19) was added to the beaker so that the available chlorine concentration shown in Table 5 was obtained. 30 minutes after adding the mixture,
Bacterial count Easy cultivation aegicult was immersed in a beaker solution, and the number of bacteria in the solution was measured simply.

[0059]

[Table 4]

The results obtained are shown in Table 5 together with the available chlorine concentration of the mixed solution to which the mixture was added.

[0061]

[Table 5]

From Table 5, it can be seen that the mixed solution of the aqueous hydrogen peroxide solution and the hydrobromic acid has an excellent sterilizing effect at an effective chlorine concentration of 0.5 mg Cl / l or more.

Measurement of Hypobromite Concentration in Test Water 3 Powder which generates peracetic acid when dissolved in water
A mixed solution was prepared using 00 (manufactured by Bachman Laboratories) and sodium bromide (special grade reagent manufactured by Kishida Chemical Co., Ltd.). First, the weight of Beuthan 1000 and sodium bromide shown in Table 6 were replaced with ion-exchanged water 10
0 ml was added and dissolved to prepare a mixed solution. Five minutes after the preparation, hypobromite (in terms of available chlorine concentration) in the mixture was measured by the ortho-tolidine method. The results obtained are shown in Table 6 together with the molarity (only sodium bromide) and the volume of the aqueous solution used.

When Beusan 1000 is dissolved in water at a concentration of 1 g / l, at least 0.35 g / l of peracetic acid is generated.
peracetic acid in aqueous solution when dissolved in
The molar concentration of 6) is obtained by the following equation. Molar concentration of peracetic acid = 0.35 / 0.1 × W / 76

[0065]

[Table 6]

A test for confirming the bactericidal effect of the powder generating peracetic acid and sodium bromide A solution containing gram-positive bacteria and gram-negative bacteria was prepared in advance (initial bacterial count: 1.0 × 10 ³ cells / ml). One liter of the resulting solution was collected in a one-liter beaker. Next, a powder that generates peracetic acid (Byusan 1000)
015 g and sodium bromide (manufactured by Kishida Chemical Co., Ltd.
(Special grade reagent) and 0.015 g are simultaneously added to a beaker,
Stir for 5 minutes. After stirring, the number of bacteria in the solution was measured by a standard agar medium method. In addition, the number of bacteria was measured in the same manner as described above for the sample without addition (blank). Table 7 shows the obtained results.

[0067]

[Table 7]

From Table 7, it can be seen that an excellent bactericidal effect is exhibited even when a substance capable of producing peracetic acid and a substance capable of supplying bromine ions are added in powder form to an aqueous system to be sterilized.

[0069]

According to the method for disinfecting an aqueous system of the present invention, the disinfecting power is not affected by the change in pH of the aqueous system to be sterilized, and the hypobromous acid and / or hypochlorite which does not easily corrode the metallic material of the structure containing the aqueous system. Hypoiodic acid can be produced inexpensively, safely and easily on-site (water system to be sterilized), and the water system to be sterilized can be significantly sterilized. In addition, this method is combined with the effect of using an unreacted raw material, such as an aqueous solution of peracetic acid or an aqueous solution of hydrogen peroxide, so that even if the amount of water or the properties of the aqueous system changes, hypobromous acid and / or hypoiodine are used. The water system to be sterilized can be remarkably sterilized without increasing the acid concentration.

[Brief description of the drawings]

FIG. 1 is a diagram showing the results of measuring the number of bacteria in a solution 1 hour, 3 hours, and 6 hours after the addition of a drug.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/50 540 C02F 1/50 540B A61L 2/16 A61L 2/16 A 2/18 2/18

Claims (8)

[Claims] 1. A substance capable of producing peracetic acid or hydrogen peroxide or an aqueous solution of peracetic acid or hydrogen peroxide, and (B) a substance capable of supplying bromine ion and / or iodine ion or bromine ion and / or Alternatively, an aqueous sterilization method comprising mixing an aqueous solution containing iodine ions in an aqueous system to be sterilized and sterilizing the aqueous system. 2. An aqueous solution of peracetic acid or hydrogen peroxide and an aqueous solution containing bromide ion and / or iodine ion are mixed in advance. A method for disinfecting an aqueous system, the method comprising: 3. The sterilization method according to claim 1, wherein the component (A) is obtained by dissolving a substance capable of producing peracetic acid or hydrogen peroxide in water. 4. The sterilization method according to claim 1, wherein the component (B) is obtained by dissolving a substance capable of supplying bromine ions and / or iodine ions in water. 5. Component (A) having a molar concentration of 0.000074
-1 mol / l aqueous solution of peracetic acid, wherein component (B) is an aqueous solution of a bromide and / or iodide of an alkali metal having a molar concentration of 0.00016-1 mol / l, wherein component (A) and component (B) The molar ratio of 1: 1 to 1:10.
The sterilization method according to any one of Items 1 to 4, wherein 6. Component (A) having a molar concentration of 0.01 to 10 mol.
1 / l hydrogen peroxide aqueous solution, wherein the component (B) is a hydrobromic acid and / or hydroiodic acid having a molar concentration of 0.01 to 30 mol / l, and the components (A) and (B) The sterilization method according to any one of claims 1 to 4, wherein the molar ratio is from 1: 1 to 1: 5. 7. The sterilization method according to any one of claims 2 to 6, wherein a mixed solution containing a bactericide is prepared immediately before being added to the aqueous system to be sterilized. 8. The method according to claim 1, wherein the effective concentration of hypobromous acid and / or hypoiodic acid in the water system to be sterilized is 0.01 to 2 mg / l in terms of effective chlorine concentration. The sterilization method as described.