JP2011153095A - Disinfection liquid and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide disinfection liquid inhibiting the ionization of hypochloric acid, also inhibiting the formation of molecular-formed chlorine by buffering the acidification accompanying with natural decomposition and enabling stable preservation for a long period of time, and a method for producing the same. <P>SOLUTION: This method for producing the disinfection liquid comprising a process of adding at least sodium hypochlorite to water to form an aqueous solution containing the hypochloric acid having a suitable concentration in accordance with the disinfection objectives in approximately 1 to 1,000 mg/L range is characterized by comprising a process of adding the organic acid consisting of any single one component or a plurality of components of acetic acid, oxalic acid, D-malic acid, adipic acid, citric acid and DL-tartaric acids as a neutralizing and buffering agent to the water. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a disinfecting solution produced by diluting sodium hypochlorite with water and a method for producing the same, and more particularly to a disinfecting solution capable of withstanding long-term storage and a producing method thereof.

  A disinfectant obtained by diluting sodium hypochlorite with water is often used for disinfecting fingers, clothes, door knobs, furniture, cooking utensils and the like. This disinfectant is usually prepared by diluting a stock solution of sodium hypochlorite (an aqueous solution having a sodium hypochlorite concentration of about 1 to 12%) with water so that the concentration of sodium hypochlorite is 0.02% to 0. It is used so as to be about 1% (1000 mg / L).

  This disinfectant solution is not always stable because the sodium hypochlorite stock solution itself is not always stable, so it is recommended to use it as soon as possible after preparation. This is considered to be because hypochlorous acid is decomposed over time, chlorine is consumed, and the sterilizing power decreases.

Therefore, conventionally, as described in Patent Document 1, attempts have been made to stabilize bromide by adding it to an aqueous sodium hypochlorite solution.
Japanese Patent Laid-Open No. 1-164701

  However, in the technique described in Patent Document 1, although a certain effect is observed for stabilization of hypochlorous acid itself having a high concentration of sodium hypochlorite stock solution level, it is possible to stabilize a disinfectant solution obtained by diluting the stock solution. Is known to have no effect.

Here, according to the study by the present inventor, the chlorinating agent includes molecular chlorine Cl ₂ , non-dissociated and molecular hypochlorous acid HOCl, and the same ion OCl ⁻ as a variable. Equilibrium relationship is established. From this equilibrium, conventionally, the generation of “molecular chlorine”, that is, chlorine gas that vaporizes with acidification, has been wary. Therefore, an alkali agent is added. For example, in a stock solution for disinfection of tap water, a chemical solution having a prescription of an effective chlorine concentration of 12%, a pH value of about 12.3, and a free alkali of 0.3% is a common commercial product.

However, since alkaline solution generates oxygen and decomposes gradually, further oxidation of "effective chlorine", that is, hypochlorous acid or the same form that exists in the disinfecting solution, may cause another toxicity. The chlorate ion ClO ₃ ⁻ is generated. Part of the oxygen generated by the decomposition of available chlorine is foamed and diffused into the gas phase. The remainder acts to increase the concentration by contributing to the production of chlorate ions with increasing liquid temperature and light irradiation, or dissolved as it is. Therefore, each material balance is difficult to be constant. In the literature, even if stored in a tank with high light shielding, the effective chlorine concentration decrease rate in July when the liquid temperature is high is 0.09% / day, and in February when the temperature is low, the decrease rate is 0.03% / day. It is reported that there will be a big difference. This difference becomes significant as the free alkali ratio increases.

In addition, it has been found that about 1/3 mol of the reduced effective chlorine concentration is changed to chlorate ion after 4 weeks from the start of storage, and the chlorate ion concentration is regulated in terms of toxicity in the tap water quality standard. The value was set. According to the current tap water quality standard, it is 0.6 mg / L or less. On the other hand, under the illumination light such as sunlight and indoor light, hypochlorous acid is mainly decomposed by ultraviolet rays, and about 2/3 mol of it is changed to chlorate ion, and the ratio is reported to increase. Yes. Furthermore, it has been reported that increasing the free alkali concentration of the sodium hypochlorite stock solution increases both the effective chlorine concentration decrease and the gradient of chlorate ion concentration increase.

On the other hand, when chloramine is produced by the reaction of ammonia NH ₃ and hypochlorous acid, the outer electrons of hypochlorous acid are excited and become unstable, so the same “decomposition reaction of oxygen generation” as in storage. The inventors have already clarified that this occurs. A hypochlorous acid decomposition side reaction occurs simultaneously with the chloramine formation reaction, and the ratio of the side reaction varies considerably depending on conditions, and may be considered to be approximately 9 to 24%. Further, as a factor for reducing the decomposition rate, in addition to a dark place where indoor lighting is also turned off, that is, complete shading and a low liquid temperature, low pH can be mentioned. It has been confirmed that this principle holds until a measured value of pH = 5.

  Therefore, even for the purpose of disinfection, the decomposition side reaction of oxygen generation is inevitable. Since the coexisting oxidizable organics consume effective chlorine, the reaction cannot be suppressed. Originally, a chemical reaction occurs when the outer electrons of each reactant move. Therefore, it is impossible to control the actions of hypochlorous acid and ions that are originally unstable in a single reaction. In the case of disinfection, the purpose is different from the chlorination or bleaching of organic matter, so it is necessary to remove dissolved substances and mixtures other than effective chlorine as much as possible when preparing chlorine water. The same is required for the solvent to be diluted, that is, water and pH adjuster.

  On the other hand, what is learned from the example of hydrogen peroxide that is common with chlorine water as an oxidizing agent is the properties of manganese dioxide, which is widely known as a catalyst for oxygen generation and decomposition. This is because many metal oxides become porous particles, and also become decomposition catalysts for dissolved ozone, chlorine dioxide and hypochlorite as well as hydrogen peroxide. The preparation operation to avoid mixing of these catalytic substances becomes a problem. As a specific example, a ternary composite oxide of titanium-silicon-zirconium is used as a catalyst for decomposing ozone in exhaust gas. It is also known that when a catalyst such as manganese dioxide is added to hypochlorite, which is also an oxidizing agent, both chlorine gas and oxygen are generated and foamed, so removing the catalyst component is a disinfecting chlorine water. It becomes an indispensable subject in the manufacture of

  Turning the point of view, the problem of the disinfection effect of the commercially available sodium hypochlorite stock solution is pointed out as an issue. When the pH exceeds 8, there is a weak point that “disinfection power is extremely reduced”. The realistic countermeasure has been to adjust the pH of the water after addition of the chlorine agent to achieve both the desired bactericidal effect and the effect of oxidative decomposition of contaminants. However, when the object of disinfection is the handle of a door, furniture, cooking utensils, home appliances or clothes, pH adjustment after application / spraying is practically impossible. Therefore, there is only a product that is diluting sodium hypochlorite stock solution and adding a small amount of a surfactant with low chlorine consumption as “mold remover” for different purposes. Dispensing methods that do not require pH adjustment of the disinfection object after use are desired.

Electrolysis of low-concentration sodium chloride (salt) water or neutralization of commercially available products with inorganic acids such as hydrochloric acid makes it easy to create a sodium hypochlorite aqueous solution with strong disinfection power using only the conventional technology. . On the other hand, in these chlorinated water neutralized with electrolyzed water or inorganic acid, there is a risk of generation of chlorine gas due to rapid progress of acidification due to decomposition or oxidation reaction of hypochlorous acid or mixing with acid during use. Is always attached. Therefore, the potential problem cannot be overcome. It is a common sense that most of the reactions in which hypochlorous acid oxidizes other chemical substances or generates oxygen itself to decompose is an acidification reaction that releases hydrogen ions H ⁺ . Actually, a hydrochloric acid-based preparation that is a detergent for toilets and the above-mentioned fungicide are used in combination, so that death due to generation of chlorine gas has also occurred. Therefore, suppression of the pH reduction of sterilizing chlorine water is required.

  The present invention has been made on the basis of the above-described elucidation results. In a disinfectant produced by diluting sodium hypochlorite with water, ionization of hypochlorous acid is suppressed, and natural decomposition is achieved. An object of the present invention is to provide a disinfectant capable of suppressing the generation of molecular chlorine by buffering the accompanying acidification and enabling stable storage for a long period of time, and a method for producing the disinfectant.

Means for solving the above-described problems are as follows.
(1) Manufacture of a disinfectant solution comprising a step of adding at least sodium hypochlorite to water to make an aqueous solution containing hypochlorous acid having a concentration according to the purpose of disinfection in the range of about 1 mg / L to 1000 mg / L A method,
A step of adding an organic acid comprising a single component or a plurality of components of any one of acetic acid, oxalic acid, D-malic acid, adipic acid, citric acid, and DL-tartaric acid to the water as a neutralizing and buffering agent. A method for producing a disinfectant solution.
(2) The disinfection according to (1), wherein the step of adding the organic acid is performed such that the pH of the aqueous solution after the addition of the organic acid is 4.5 to 5.5. Liquid manufacturing method.
(3) The disinfection according to (1) or (2), further comprising a step of adding an alkaline agent to the water so that the pH of the disinfectant solution is finally 5.0 to 6.0. Liquid manufacturing method.
(4) As the water, water obtained by filtering tap water or chlorinated water with a hollow fiber membrane or an organic polymer membrane having pores smaller than the pores of the hollow fiber membrane is used ( The method for producing a disinfectant according to any one of 1) to (3).
(5) The step of adding the sodium hypochlorite to an aqueous solution containing hypochlorous acid having a concentration according to the disinfecting purpose is such that the hypochlorous acid concentration is slightly lower than the concentration according to the disinfecting purpose. It is a process to add so that
The step of adding the organic acid is a step of adding the organic acid so that the pH of the aqueous solution after adding the organic acid is 4.5 to 5.5,
Next, a small amount of sodium hypochlorite is added to the water that has undergone each of the above steps so that the concentration of hypochlorous acid becomes a concentration corresponding to the purpose of disinfection, and the pH is adjusted to 5.0 to 6.0. The method for producing a disinfectant solution according to any one of (1) to (4), further comprising a step of final preparation by adding an alkali agent.
(6) A disinfectant containing hypochlorous acid at a concentration according to the purpose of disinfection in water,
Furthermore, an alkali agent and an organic acid composed of any one or more of acetic acid, oxalic acid, D-malic acid, adipic acid, citric acid, and DL-tartaric acid are included. An antiseptic solution, characterized in that the organic acid required for neutralization of free alkali and the organic acid required for weak acidification have substantially equimolar concentrations and a pH of 5.0 to 6.0.

According to the above-mentioned means (1), even if hypochlorous acid, which is free effective chlorine, is decomposed for some reason and the pH is lowered, the buffering agent works reliably to buffer / suppress pH fluctuations and decompose. Suppress. Moreover, it is a fact that has been elucidated for the first time by the study of the present inventor, but it has been found that acetic acid, oxalic acid, D-malic acid and adipic acid do not consume chlorine at all in the dark. In addition, it has been found by the inventor's research that the chlorine consumption of propionic acid, formic acid, citric acid and DL-tartaric acid is very small if not all. For these organic acids, the catalytic action after the start of decomposition can be ignored. Furthermore, in the case of disinfecting chlorinated water, even if it is taken orally, no damage is caused. Therefore, it is possible to stabilize the effective chlorine concentration and maintain it for a long period of time by filling the disinfectant in a light-shielding container that does not use metal or additive-containing plastics that catalyze the decomposition of effective chlorine as the liquid contact material. , Commercialization and distribution become easy.
According to the above-mentioned means (2) to (5), it is possible to more buffer and suppress the pH fluctuation and to further suppress the decomposition. Here, according to the means (4), by filtering with a hollow fiber membrane or the like,
Since metal oxide particles that can be a catalyst contained in tap water can be removed, the effective chlorine can be prevented from being decomposed more effectively.
According to the above means (6), the ionization of hypochlorous acid is suppressed, and the generation of molecular chlorine is suppressed by buffering the acidification associated with natural decomposition, thereby enabling long-term stable storage. Can be obtained.

It is explanatory drawing of the manufacturing method of the disinfection liquid concerning embodiment of this invention. It is explanatory drawing of the manufacturing method of the disinfection liquid concerning embodiment of this invention.

  FIG.1 and FIG.2 is explanatory drawing of the manufacturing method of the disinfection liquid of this invention. Hereinafter, a disinfectant solution and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to these drawings.

  In the method for producing a disinfectant according to the embodiment, sodium hypochlorite is added to water so that the concentration of hypochlorous acid is within a range of about 1 mg / L to 1000 mg / L according to the purpose of disinfection. Then, by adding an organic acid, the pH becomes 4.5 to 5.5, and the organic acid required for neutralizing the free alkali and the organic acid required for weak acidity are approximately equimolar. Then, an antiseptic solution is obtained by adding an alkaline agent so that the final pH is 5.0 to 6.0. In the above preparation step, it is important not to mix an inorganic acid having no pH buffering power such as hydrochloric acid or sulfuric acid or a mixture of these inorganic acid and organic acid.

  As water, tap water or chlorinated water in Japan, etc., where the regulation of residual chlorine concentration is regulated, is a hollow fiber membrane or an organic polymer membrane having pores smaller than the pores of the hollow fiber membrane. Use filtered water. The tap water is used in this way because the tap water transfer pipe and storage vessel are naturally subjected to oxidation treatment with hypochlorous acid remaining in the tap water. This is because it can be prevented beforehand. As the sodium hypochlorite to be added, for example, a 12% sodium hypochlorite stock solution having a free alkali of 2% or less used as a stock solution for disinfection at the time of disinfection of tap water is used. As an organic acid as a neutralizing and buffering agent, any single component or multiple components of acetic acid, oxalic acid, D-malic acid, adipic acid, citric acid, and DL-tartaric acid are used. As the alkali agent, an inorganic alkali agent such as sodium hydroxide or sodium hydrogen carbonate is used.

  First, as shown in FIG. 1, tap water from the tap tap 1 is introduced into the hollow fiber membrane filtration device 2 and filtered, and the filtered water is stored in the dilute water storage container 3 as diluted water. The dilution water storage container 3 is pre-cleaned with chlorine water. The tap water is introduced into the hollow fiber membrane filtration device 2 and the filtered water is used for the following reason. In other words, it is necessary to thoroughly remove the catalytic substance mixed in the aqueous solution during the circulation and storage of the sterilizing chlorine water. This is because the porous solid, metal oxide, organic oxide, or organic peroxide must be completely decomposed or removed by filtration from water as a solvent.

  Next, as shown in FIG. 2, the opening / closing valve 8 of the dilution water storage container 3 is opened, and a predetermined amount of dilution water is put into the disinfectant preparation container 7. Next, the on-off valve 9 of the sodium hypochlorite stock solution storage container 4 is opened, and the sodium hypochlorite solution is added to the diluting water in the disinfectant preparation container 7. Close 9

  Next, while the agitator 12 is driven, the on-off valve 10 of the organic acid storage container 5 is opened, the organic acid 5 is added to the diluted water of the disinfectant preparation container 7, and the pH from the final target is observed while looking at the pH meter 13. When the value is lowered by 0.2 to 0.5 pH, the on-off valve 10 is closed.

  Next, the on-off valve 9 of the sodium hypochlorite stock solution storage container 4 is opened, and a small amount of sodium hypochlorite is added to the diluted water in the disinfectant preparation container 7 to finally prepare the effective chlorine concentration to a predetermined concentration. At the same time, the on-off valve 11 of the inorganic alkaline agent storage container 6 is opened, and a small amount of an inorganic alkaline agent solution such as sodium hydroxide is finally added until the pH becomes 5.5 ± 0.5. Obtain a liquid. In the final adjustment operation, the effective chlorine concentration and pH are finally adjusted through excessive neutralization. That is, it is a method devised to obtain a sufficient pH buffering effect that ensures the concentration and ratio of the same ions as the non-dissociated / molecular organic acid even when heterogeneous mixing occurs.

  That is, one of the conditions that the disinfecting chlorine water should have is a pH buffering effect. This is an effect of suppressing acidification accompanying hypochlorous acid autolysis and oxidation reaction, that is, pH reduction. In order to maintain the liquidity of the chlorine water within a pH range where molecular chlorine is not generated, a mixed solution of an organic acid and the same salt is optimal. Further, the present inventors have found from the experimental results of the chlorine demand measurement that the residual chlorine form is only non-dissociated and molecular hypochlorous acid at pH = 4.5 to 5.5, and the decomposition and the like. Confirmed that reaction is minimal. There is almost no molecular chlorine or hypochlorite ion.

  In addition, although there is almost no pH change with time of 12% sodium hypochlorite solution for water supply, the effective chlorine concentration decreases by about 0.9 to 2.3% in one month. If the free alkali is eliminated, the production of chlorate ions can be suppressed. The inventor has also clarified that nitrogen-containing compounds such as ammonia and amino acids themselves serve as a catalyst for the decomposition of hypochlorous acid. On the other hand, the phenomenon that ozone water and hydrogen peroxide water decompose and generate oxygen bubbles in the water has long been a well-known fact as foaming of “oxide”. The foaming is catalyzed by earth and sand adhering to the wound, red blood cells containing iron complexes, and oxidized protein. If there is a water receiving tank or a water storage tank in the middle of water supply, it is necessary to assume the mixing of organic solids.

  The above pre-cleaning with chlorinated water is a countermeasure from this viewpoint. For example, it is also known in the measurement operation of potassium permanganate consumption, etc., but it is a well-known fact that although the oxidation reaction rate at the beginning of titration is slow, the reaction rate rapidly increases once decolorization is started. . This is the catalytic effect of the porous oxide produced by the oxidation reaction. The solid substance that can be assumed to have a catalytic action in the tap water is first rust that peels from the water supply equipment such as piping. Rust is a metal oxide, and flows out as iron oxide and manganese dioxide particles by surviving iron and manganese bacteria, or by the action of residual chlorine. Of course, the solid may be considered porous.

  Although complete removal of the solids by sand filtration or diatomaceous earth filtration cannot be expected, the passage of the fine particles can be completely prevented if the hollow fiber membrane or ultrafiltration membrane has pores. Water purifiers equipped with hollow fiber membranes are already on the market. Therefore, by passing water through the hollow fiber membrane filtration device 2 of FIG. 1, solid matter that can be a decomposition catalyst, whether inorganic or organic, is completely removed from the tap water to enter the diluted water storage container 3. It has also become easier to store.

As the organic acid 5 serving as a neutralizing and buffering agent, a single component dilution or a mixed dilution of any of acetic acid, oxalic acid, D-malic acid, adipic acid, citric acid, and DL-tartaric acid is used. As a buffering agent, an optimal prescription is an equimolar mixture of organic acid and the same salt that does not consume chlorine or a trace amount of organic acid. About the chlorine consumption of organic acid, the inventor has reported in the past in "Water Supply Association Magazine" (Water Supply Association Magazine 483, No. 12, 15-25 (1974)). Accordingly, salicylic acid and phenol (coal acid) acting as an acid have been found to consume a large amount of chlorine even in the dark, and are not included in the organic acid options of the present invention. In addition, in the above preparation process, it is important not to mix an inorganic acid having no pH buffering power, such as hydrochloric acid or sulfuric acid, or a mixture of these inorganic acid and organic acid. Excluded from choice.

  The reason for intentionally excluding the presence of inorganic acids having no pH buffering power, such as hydrochloric acid and sulfuric acid, and mixtures of these inorganic acids and organic acids in the preparation step is as follows. That is, the buffer solution of chloride ion and hydrochloric acid (hydrogen chloride) has a pH of 1.0 to 2.2, and the buffer solution of dihydrogen phosphate ion and sodium hydroxide has a pH of 5.8 to 8. Although it is prepared in the region of 0 and exhibits a buffering effect, it is not suitable for the preparation of pH = 5.5 ± 0.5, which is the object of the present invention. Even when neutralized with sulfuric acid, the reversible dissociation equilibrium tends to be strongly acidic. Rather, since the pH is drastically lowered due to the mixing of these inorganic acids, when mixed with an organic acid, there is a problem that the “buffer ratio” between the non-dissociated organic acid and the same ion cannot be grasped.

Furthermore, it is because of the following reasons. That is, the solubility (with respect to water) of hydrogen chloride HCl is extremely high, and ion dissociation is almost complete.
Hydrochloric acid HCl → H ⁺ + Cl ⁻
Here, the buffer effect is exhibited by the following equilibrium (⇔).
Phosphoric acid H ₃ PO ₄ ⇔H ⁺ + H ₂ PO ₄ ⁻ ⇔2H ⁺ + HPO ₄ ²⁻
⇔3H ⁺ + PO ₄ ³⁻
Carbonic acid H ₂ CO ₃ ⇔H ⁺ + HCO ₃ ⁻ ⇔2H ⁺ + CO ₃ ²⁻
Acetic acid CH ₃ COOH⇔H ⁺ + CH ₃ COO ⁻

Therefore, when neutralizing sodium hypochlorite solution (a product in which free alkali remains), which is dissolved in water and shows strong acidity, such as hydrochloric acid, nitric acid, and sulfuric acid, most of the acid is ionically dissociated. . Naturally, most of the assumed reactions such as decomposition of hypochlorite HOCl itself, nitric acid formation reaction, and natural decomposition of dichloramine NHCl ₂ produced by reaction with mixed ammonia etc. are oxidation reactions, so buffering effect Acidification proceeds without exhibiting.

With the progress of the ^{_{acidification, Cl 2 + H 2 O⇔HOCl +}} H + + Cl - ⇔OCl - + 2H + + Cl - equilibrium proceeds toward the left, increasing chlorine gas diffusion into the gas phase from the aqueous solution of hypochlorous acid To do. The boundary of pH at which the equilibrium changes to the structure of Cl ₂ is approximately 4.0, and it is absolutely necessary to avoid pH = 4.5 or less in view of the safety during the distribution of the chemical solution. Therefore, it is concluded that the use of an inorganic acid that does not guarantee a buffering effect for maintaining the pH as a neutralizing agent is “impossible from the viewpoint of safety”.

  The main object of the present invention is to maintain pH = 4.5 to 6.0, which does not generate molecular chlorine even when disinfecting chlorine water is mixed with a small amount of acid, and can suppress diffusion of chlorine gas into the gas phase. There is to do. Therefore, it is a matter of course that the strong microbial inactivation power (bactericidal power) of non-dissociated and molecular hypochlorous acid is fully exhibited at pH = 4.5 to 6.0. But there is. It does not mean that the pH should be lowered appropriately in order to enhance the sterilizing power of the sterilizing chlorine water. In the weakly acidic region, the strength of pH buffering power (so-called buffer action) is the most important factor.

  Accordingly, the pH target value of disinfecting chlorine water is expanded from the present invention, and including a region where pH = 4.5 or less, such as pH = 3.0 to 6.0, is a rapid increase of molecular chlorine and a gas phase. It must be avoided because it causes the diffusion of chlorine gas. For this reason, the present invention sets the substantial lower limit to pH = 4.5 even when the variation in pH at the time of preparation is taken into consideration.

For example, a case where acetic acid is selected as the organic acid will be described. Both equimolar mixtures of acetic acid and sodium acetate are ionically dissociated to produce acetate ions CH ₃ COO ⁻ together at a constant ratio. The equimolar cation relative to this anion is hydrogen ion for acetic acid and sodium ion Na ⁺ for sodium acetate. pH = pKa-log [CH ₃ COOH] /
It is defined as [CH ₃ COO ⁻ ], and in an equimolar mixture, “−log [CH ₃ COOH] / [CH ₃
COO ⁻ ] = − log 1 = 0 ”, and the dissociation constant pKa of this equation is calculated to be 4.73 at 18 ° C. Therefore, there is no pH change even if the equimolar mixture is diluted. Further, even when the ratio of molecular and non-dissociated acetic acid to the same ion is 10/1, or conversely, 1/10, the pH changes only by pH = 3.73 to 5.73, that is, ± 1.

In some cases, it is better not to intentionally add sodium acetate to prepare a mixed buffer of acetic acid and sodium acetate. In principle, free alkali (substantially sodium ion Na ⁺ ) exists in hypochlorous acid stock solution, and equimolar acetic acid is ionically dissociated into acetate ion. The “buffer ratio” of the same ions as acetic acid is determined. In the case of inorganic acids, most of them are ion-dissociated, and the “buffer ratio” of the same ions as organic acids such as acetic acid cannot be determined.

Table 1 is a table showing changes in the effective chlorine concentration of the disinfecting solution over time. The upper part of Table 1 shows the time course of the chlorine concentration when 12% hypochlorous acid stock solution was stored in a large container with a capacity of 1 m ³ (Osaka City Waterworks Bureau Water Quality Laboratory (1993)). The time course of the chlorine concentration when a 12% hypochlorous acid stock solution is stored in a small container with a capacity of 20 L is shown. The lower part shows the disinfectant according to the present embodiment (hypochlorous acid concentration is 80 mg / L). Shows the time course of the chlorine concentration when stored in a 20 L container. As is clear from Table 1, in the conventional one, the chlorine concentration decreased with time even in the 12% stock solution, and as shown in the middle row of Table 1, the one stored in a 20 L container had an effective chlorine concentration in 120 days. Is 50% of the original. In contrast, the disinfectant prepared by the method according to the above embodiment has an effective chlorine concentration even after 240 days (about 8 months) even though the hypochlorous acid concentration is as low as 80 mg / L. It has been confirmed that there is almost no change in the product and long-term efficacy can be guaranteed.

The present invention enables long-term storage of the sterilized chlorine water by dissolving effective chlorine in a weakly acidic buffer solution that does not contain a substance that catalyzes a side reaction such as decomposition. In addition, in the storage / distribution process of the chlorine water, it is possible to guarantee the quality of the molecular chlorine, that is, chlorine gas generated by the equilibrium reaction so that the pH is not less than 4 or less. Therefore, the chlorinated water according to the present invention is used for the prevention of infectious diseases caused by pathogenic microorganisms / viruses. Can be used to disinfect home appliances and clothing surfaces.

DESCRIPTION OF SYMBOLS 1 ... Water tap 2 ... Hollow fiber membrane filtration apparatus 3 ... Dilution water storage container 4 ... Sodium hypochlorite stock solution storage container 5 ... Organic acid storage container 6 ... Inorganic alkaline agent storage container 7 ... Disinfectant preparation container 8-11 ... Open / close valve 12 connected to each container ... Stirrer 13 ... pH meter

Claims (6)

A method for producing a disinfectant solution comprising a step of adding at least sodium hypochlorite to water to obtain an aqueous solution containing hypochlorous acid having a concentration according to the purpose of disinfection in the range of about 1 mg / L to 1000 mg / L. And
A step of adding an organic acid comprising a single component or a plurality of components of any one of acetic acid, oxalic acid, D-malic acid, adipic acid, citric acid, and DL-tartaric acid to the water as a neutralizing and buffering agent. A method for producing a disinfectant solution.   The step of adding the organic acid is performed so that the pH of the aqueous solution after the addition of the organic acid is 4.5 to 5.5. Method.   The method for producing a disinfectant according to claim 1 or 2, further comprising a step of adding an alkaline agent to the water so that the pH of the disinfectant finally becomes 5.0 to 6.0.   2. The water obtained by filtering tap water or chlorinated water with a hollow fiber membrane or an organic polymer membrane having pores smaller than the pores of the hollow fiber membrane is used as the water. 4. A method for producing a disinfectant solution according to any one of 3 above. The step of adding sodium hypochlorite to an aqueous solution containing hypochlorous acid having a concentration corresponding to the purpose of disinfection so that the concentration of hypochlorous acid is slightly lower than the concentration corresponding to the purpose of disinfection. Adding process,
The step of adding the organic acid is a step of adding the organic acid so that the pH of the aqueous solution after adding the organic acid is 4.5 to 5.5,
Next, a small amount of sodium hypochlorite is added to the water that has undergone each of the above steps so that the concentration of hypochlorous acid becomes a concentration corresponding to the purpose of disinfection, and the pH is adjusted to 5.0 to 6.0. The method for producing a disinfectant solution according to any one of claims 1 to 4, further comprising a step of final preparation by adding an alkali agent. Disinfecting solution containing hypochlorous acid at a concentration according to the purpose of disinfection in water,
Furthermore, an alkali agent and an organic acid composed of any one or more of acetic acid, oxalic acid, D-malic acid, adipic acid, citric acid, and DL-tartaric acid are included. An antiseptic solution, characterized in that the organic acid required for neutralization of free alkali and the organic acid required for weak acidification have substantially equimolar concentrations and a pH of 5.0 to 6.0.

Images