JP2009274950A - Method for preparing molecular hypochlorous acid solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for preparing a molecular hypochlorous acid solution in which a trihalomethane is hardly produced even when being brought into contact with organic matter, and production of chloric acid is minimum even when it is preserved, salts are not contained at all and which has high sterilizing power, and to provide a molecular hypochlorous acid solution. <P>SOLUTION: A hypochlorous acid solution is treated with a hydrogen ion exchange type cation exchange resin so as to substitute the metal ions with hydrogen ions, thereafter, the treated solution is treated with a hydroxide ion exchange type anion exchange resin so as to substitute chlorine ions with hydroxide ions, thus a molecular hypochlorous acid solution is prepared. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a technique for preparing a stable molecular hypochlorous acid solution. More specifically, the present invention relates to a technique for preparing a stable molecular hypochlorous acid solution by replacing metal ions contained in a hypochlorite solution with hydrogen ions and replacing chlorine ions with hydroxide ions. is there.

Hypochlorite solutions such as sodium hypochlorite are the most used fungicides in the world for many years and in a wide range of fields. In particular, sodium hypochlorite is used in most areas of food production, distribution and provision, as well as water supply facilities, wastewater treatment, swimming pools, hot springs, public baths, medical care, nursing care, agriculture and fisheries, and general households. I have no time to enumerate. In order to meet these demands, the annual shipment amount in Japan is about 1 million tons, and it is estimated that the worldwide shipment amount is several tens of times.

Although it is a hypochlorite solution that is used in such a wide range, several problems have been pointed out so far. One of them is the generation of trihalomethane. Trihalomethane has been confirmed to be generated when an alkaline chlorinating agent comes into contact with organic matter, and has become a global problem since it is known that a kind of trihalomethane, chloroform, has carcinogenic activity even at low concentrations. In some countries where this is important, the use of food and drinking water is restricted.

The second problem is that of bromic acid and chloric acid. Bromic acid is derived from the impurities of sodium chloride, the raw material of sodium hypochlorite, but chloric acid is generated by disproportionation decomposition of hypochlorite itself, both of which are toxic to the human body. Therefore, in recent years, the upper limit concentration was set in the Water Supply Law and related laws and regulations. Several acceleration factors are known for the chloric acid production reaction, one of which is the hypochlorite concentration, and the production rate increases in proportion to the concentration. It is also known that the contained salt or heavy metal contained in the mixture accelerates the reaction.

The third problem is insufficient sterilization power. One of the reasons why hypochlorite solutions are widely used is that they are effective against a wide range of microorganisms compared to other fungicides, but they have no practical effect on bacterial spores. For tuberculosis bacteria, there is also a weak point that the effect is not seen unless the concentration is higher than 1000 ppm. A 1000 ppm hypochlorite solution has extremely large adverse effects on people, objects and the environment, and has a great limitation on the purpose of use. This is because the hypochlorite solution is strongly alkaline, so most of the hypochlorite radicals exist as hypochlorite ions. Most of the bactericidal effects of hypochlorite solutions are borne by the molecular hypochlorous acid contained, but when the liquid becomes alkaline and ionizes, the bactericidal power, especially the bactericidal speed, is greatly attenuated. is there. In order to compensate for this, it is used at a high concentration, but as described above, various problems due to the use of the high concentration have also occurred. For example, damage to objects, causes of strange odors, generation of harmful substances, rough skin, obstacles to wastewater treatment, environmental pollution, and the like.

The last problem is due to the salt content. A typical sodium hypochlorite solution among hypochlorites contains by-product sodium chloride and raw material sodium hydroxide in addition to sodium ions as counter ions of hypochlorite ions. It is known that sodium hypochlorite decomposes only by leaving it to become salt or changes to chloric acid by disproportionation reaction, but as described above, salt promotes the reaction. In addition, when sodium and free chlorine coexist, the action of rusting the metal becomes stronger, and it is concentrated when dried on the surface of the metal, and even a corrosion resistant material such as stainless steel may cause rust. Moreover, when sprayed for the purpose of indoor sterilization, humidification, or deodorization, salt accumulates, causing indoor salt contamination and electrical product failure.

Furthermore, if the hypochlorite does not contain salt, it can be used in industries that dislike salt residue. Hypochlorous acid is originally an extremely strong oxidizing agent, and can be used for the purpose of removing dirt and impurities using its oxidizing power. However, until now, the salt was inevitably contained, so that it could not be used for these purposes. Therefore, if a pure hypochlorous acid solution is made, it is expected that the application area will be further expanded.

Various ideas have been made for the purpose of compensating for the drawbacks of hypochlorite. Above all, the method of increasing the bactericidal power by adding various acids to sodium hypochlorite solution to lower the pH and increasing the ratio of molecular hypochlorous acid has been performed for a long time. Many are commercially available. However, this method certainly enhances the bactericidal power, but the sodium contained therein remains as it is, so the harmful effects of salts cannot be solved. In addition, there have been a number of reports of accidents due to the dangerous contraindication process of mixing sodium hypochlorite solution and acid.

Patent Document 1 discloses that the pH of a hypochlorite solution is obtained by subjecting a hypochlorite solution or water for diluting the hypochlorite solution to ion exchange treatment with a hydrogen-substituted ion exchange material. How to lower is shown. However, this method is only intended to lower the pH of the hypochlorite solution, and as a result, similar to the method of adding an acid to the hypochlorite solution described above, most of the contained metals are Remaining. Also, if a certain amount or more of metal ions contained in the hypochlorite solution is replaced with hydrogen ions by this method, the pH becomes extremely low and chlorine gas is generated, which is dangerous.

JP-A-6-206076

Therefore, the problem to be solved by the present invention is a technique for preparing a molecular hypochlorous acid solution that minimizes the production of trihalomethane and bromic acid, does not contain salts, and has high bactericidal activity, and molecular hypochlorous acid. It is to provide a chloric acid solution.

A commercially available hypochlorite solution contains chloride or alkali hydroxide as a normal component in addition to hypochlorite. What makes the liquidity of a hypochlorite solution strong alkalinity is a metal ion which is a counter ion of hypochlorite ion and a hydroxide of alkali or alkaline earth metal. Therefore, if all the metal ions are replaced with hydrogen ions, the alkalinity is eliminated and there is no residual salt when dried. On the other hand, chlorine ions contained in the salt are combined with hydrogen ions substituted for sodium ions to form hydrochloric acid. Therefore, the liquidity becomes strongly acidic only by treating with a hydrogen ion exchange type cation exchange resin, and hypochlorous acid molecules become unstable and volatilize as chlorine.

Therefore, in order to stabilize hypochlorous acid, it is necessary to subsequently treat with a hydroxide ion exchange type anion exchange resin and replace chlorine ions remaining in the solution with hydroxide ions. Also, by these treatments, all of the interstitial ions originally contained in the hypochlorite solution are removed, so that a pure hypochlorous acid solution can be obtained.

In these ion exchange treatments, it is important to carry out the anion exchange resin treatment after the cation exchange resin treatment. Since the hypochlorite solution is initially strongly alkaline, the hypochlorite is ionized, and ions such as metal ions, hypochlorite ions, chlorine ions, and hydroxide ions are present. Of these, only metal ions are removed when treated with a hydrogen ion exchange type cation exchange resin. However, if it is first treated with an anion exchange resin, important hypochlorite ions are removed. When treated with a cation exchange resin, metal ions are exchanged for hydrogen ions, so the liquidity becomes strongly acidic, and the chemical species contained in the treated solution change to molecular hypochlorous acid, hydrogen ions, and chlorine ions. To do. When this is treated with a hydroxide ion exchange type anion exchange resin, chlorine ions are replaced with hydroxide ions, which react with hydrogen ions to become water, so the only remaining chemical species in the solution is molecular hypochlorous acid. When all the treatments are completed, the liquidity becomes weakly acidic. Thus, since it was confirmed that a pure molecular hypochlorous acid solution was produced | generated, each aspect of the means for solving a problem was made as follows.

First, after treating a hypochlorite solution with a hydrogen ion exchange type cation exchange resin and replacing metal ions with hydrogen ions, the treatment solution is treated with a hydroxide ion exchange type anion exchange resin, The method of preparing a molecular hypochlorous acid solution by substituting with a hydroxide ion is the first aspect of the means for solving the problem.

In the first aspect, a part of the solution after the treatment with the hydrogen ion exchange type cation exchange resin is not treated with the hydroxide ion exchange type anion exchange resin, and the remaining part is treated with the hydroxide ion exchange type anion exchange resin. A method of mixing a solution treated with an ion exchange resin and not treated with the hydroxide ion exchange type anion exchange resin and a solution treated with the hydroxide ion exchange type anion exchange resin It was set as the 2nd aspect.

In the first or second aspect, the pH of the solution after treating the hypochlorite solution with a hydrogen ion exchange type cation exchange resin and replacing metal ions with hydrogen ions is 6.5 or less. It was set as the 3rd aspect of the means for solving a subject that it is 5 or more.

In any one of the first and second embodiments, the hypochlorite solution is treated with a hydrogen ion exchange type cation exchange resin, the metal ions are replaced with hydrogen ions, and then the treatment liquid is subjected to a hydroxide ion exchange. It was set as the 4th aspect of the means for solving a problem that the pH of the process liquid after processing with a type | mold anion exchange resin and replacing chlorine ion with a hydroxide ion is 8 or less 4 or more.

In addition, a method for preparing a molecular hypochlorous acid solution obtained by further diluting the molecular hypochlorous acid solution obtained by any one of the first to fourth aspects with water is a means for solving the problems. It was set as the 5th aspect.

In any one of the first to fifth aspects, the hypochlorite is sodium hypochlorite as a sixth aspect of means for solving the problem.

The molecular hypochlorous acid solution obtained according to any one of the first to sixth aspects is used as the seventh aspect of the means for solving the problem.

The effects of the present invention are as follows. First, after treating a hypochlorite solution with a hydrogen ion exchange type cation exchange resin and replacing metal ions with hydrogen ions, the treatment solution is treated with a hydroxide ion exchange type anion exchange resin, Is replaced with hydroxide ions, so that the contained chlorine ions can be removed without wasting the effective chlorine originally contained in the hypochlorite solution, and the desired liquid free free hypochlorite can be removed. A chloric acid solution can be obtained.

In addition, a part of the solution after treatment with the hydrogen ion exchange type cation exchange resin is not treated with the hydroxide ion exchange type anion exchange resin, and the rest is treated with the hydroxide ion exchange type anion exchange resin. The pH of the molecular hypochlorous acid solution finally obtained by mixing the solution not treated with the hydroxide ion exchange type anion exchange resin and the solution treated with the hydroxide ion exchange type anion exchange resin Can be adjusted appropriately.

Further, the hypochlorite solution was produced by treating with a hydrogen ion exchange type cation exchange resin and replacing the sodium ions with hydrogen ions so that the pH of the solution was 6.5 or less and 2.5 or more. Hypochlorous acid exists in the form of molecules instead of ions or gases, and dangerous gas is generated in the process and loss due to volatilization can be prevented. Hypochlorous acid to the exchange resin by anion exchange in the next process Adsorption loss can also be prevented.

Further, after treating the hypochlorite solution with a hydrogen ion exchange type cation exchange resin and replacing metal ions with hydrogen ions, the treatment solution is treated with a hydroxide ion exchange type anion exchange resin to produce chlorine ions. Hypochlorous acid produced by setting the pH of the treatment solution after the substitution of hydroxide ions to 8 or less and 4 or more does not ionize and exists stably in a molecular form having strong bactericidal power.

In addition, the obtained molecular hypochlorous acid solution is further diluted with water to prepare the molecular hypochlorous acid solution. It can be used as it is without spending.

In addition, by using sodium hypochlorite as the hypochlorite, it is the most widely distributed hypochlorite, so it is easy to obtain a stable raw material, and since it is liquid, it is molecular. Increased convenience in handling hypochlorous acid solution production has made it possible to industrialize production.

Then, by providing a molecular hypochlorous acid solution obtained by any one of the methods described above, it can be used for various purposes without requiring a generating device.

Flow chart of an embodiment of the present invention

The minimum equipment for carrying out the present invention comprises an anion exchange cylinder, a cation exchange cylinder, a hypochlorite solution supply means, a dilution water supply means, a flow path opening / closing means and a mixing and stirring means. Hypochlorite, chlorine-resistant or alkali-resistant resins are recommended for the wetted parts of each part. Any ion exchange resin can be used, but a resin material that is durable to chlorine is convenient for long-term use. If the ion exchange capacity is lost, it can be used repeatedly if it is regenerated by a conventional method. For the regeneration of the ion exchange resin, this generating device may be used, or a separate regeneration facility may be installed.

The sodium hypochlorite solution or the like used in the present invention preferably has a low salt content, but is not limited thereto, and any one can be used. Also, a product with a short number of days after production is desirable. There is no particular limitation on the chlorine concentration. When it is necessary to lengthen the storage period of the resulting hypochlorous acid solution, it is desirable to adjust the pH as close to 7 as possible, and when using it immediately, it may be arbitrarily adjusted between 4 and 7. If the pH is less than 4, it is not recommended because the generation of chlorine gas is expected to reduce the shelf life of the effect and affect the surroundings.

Next, the preparation process of a molecular hypochlorous acid solution is demonstrated in detail using FIG. 1 which shows an Example. Raw water is supplied from the raw water inlet 1 into the apparatus. The raw water supply pipe is provided with a solenoid valve 2 and a low flow valve 3 to control the supply stop and quantitative supply of the raw water. A part of the supplied raw water is diverted by the metering pump 4 for diluting the hypochlorite solution, and the remainder is used for the final dilution of the molecular hypochlorous acid solution.

The raw water diverted for diluting the hypochlorite solution is mixed with the hypochlorite solution stored in the hypochlorite solution tank 5 and quantitatively withdrawn by the hypochlorite solution pump 6. Further, the mixture is uniformly mixed by the static mixer 7 and supplied to the cation exchange cylinder 8 filled with the hydrogen ion exchange type cation exchange resin.

In the cation exchange cylinder, metal ions contained in the solution are replaced with hydrogen ions, so that the liquidity of the discharged solution is strongly acidic. A part thereof is supplied from the bypass pipe 13 through the throttle valve 14 to the final dilution process. All the remainder is supplied to an anion exchange cylinder 9 filled with a hydroxide ion exchange type anion exchange resin. In the anion exchange cylinder, chlorine ions contained in the solution are replaced with hydroxide ions, so that the liquidity of the discharged liquid becomes substantially neutral.

The solution discharged from the anion exchange tube is mixed with the solution directly discharged from the cation exchange tube, pH is adjusted, and the solution is uniformly mixed by the final static mixer 11 and discharged from the discharge port 12. An in-line type pH meter 15 is disposed near the discharge port so that the pH of the final discharged liquid can be checked.

In this equipment, AMBERJET1020H made by Organo is used for the cation exchange resin, AMBERJET4002Cl made by the company is used for the anion exchange resin, ultrafiltered water is used as raw water, and a 6% sodium hypochlorite solution is used as a raw material. As a result, a pure molecular hypochlorous acid solution having a pH of 6.5 to 6.0 and an effective chlorine concentration of about 1000 ppm was continuously obtained at 1 ton per hour.

The present invention provides a bactericidal agent having a strong bactericidal power not containing salts and a method for adjusting the bactericidal agent. This disinfectant is used in fields such as food industry, medical care industry, water treatment, sewage treatment, public bath, swimming pool, semiconductor industry, and building air conditioning. Particularly suitable for applications where the inclusion of salts is a problem.

1 Raw water inlet 2 Solenoid valve 3 Constant flow valve 4 Dilution metering pump 5 Hypochlorite solution tank 6 Hypochlorite solution metering pump 7 Static mixer 8 Cation exchange tube 9 Anion exchange tube 10 Dilution water piping 11 Static mixer 12 Molecular hypochlorous acid solution outlet 13 Cation exchange liquid bypass 14 Throttle valve 15 pH meter

Claims (7)

After treating the hypochlorite solution with a hydrogen ion exchange type cation exchange resin and replacing metal ions with hydrogen ions, the treatment solution is treated with a hydroxide ion exchange type anion exchange resin, and the chlorine ions are treated with water. Method for preparing a molecular hypochlorous acid solution by substitution with acid ions A part of the solution after the treatment with the hydrogen ion exchange type cation exchange resin is not treated with the hydroxide ion exchange type anion exchange resin, and the remaining part is treated with the hydroxide ion exchange type anion exchange resin. The molecular hypochlorous acid solution according to claim 1, wherein a solution not treated with an acid ion exchange type anion exchange resin and a solution treated with the hydroxide ion exchange type anion exchange resin are mixed. how to The hypochlorite solution is treated with a hydrogen ion exchange type cation exchange resin, and the pH of the solution after replacing metal ions with hydrogen ions is 6.5 or less, 2.5 or more, A method for preparing the molecular hypochlorous acid solution according to claim 1 or 2. After treating the hypochlorite solution with a hydrogen ion exchange type cation exchange resin and replacing metal ions with hydrogen ions, the treatment solution is treated with a hydroxide ion exchange type anion exchange resin, and the chlorine ions are treated with water. The method for preparing a molecular hypochlorous acid solution according to any one of claims 1 to 3, wherein the pH of the treatment liquid after substitution with acid ions is 8 or less and 4 or more. A method for preparing a molecular hypochlorous acid solution by further diluting the molecular hypochlorous acid solution obtained by the method according to claim 1 with water. 6. The method for preparing a molecular hypochlorous acid solution according to claim 1, wherein the hypochlorite is sodium hypochlorite. A molecular hypochlorous acid solution obtained by the method according to any one of claims 1 to 6.