JPH09253651A - Apparatus and method for making sterilized water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain sterilizing water having pH highest in a presence ratio of hypochloric acid having strong sterilizing power scarcely generating chlorine gas during the production of sterilizing water by providing a diaphragm free electrolytic cell and using dilution water adjusting electrolytic water obtained by electrolysis to desired pH and adding hydrochloric acid to dilution water. SOLUTION: Water to which sodium chloride is added being an electrolyte 5 is alowed to flow through a diaphragm free electrolytic cell 1 using an anode 2 and a cathode 3 to be electrolyzed by using the predetermined voltage and current of a DC power supply 6. The electrolyzed electrolyte, that is, electrolytic water is diluted with a mixed soln. prepared by adding an aq. hydrochloric acid soln. 8 to raw water 4 to obtain sterilizing-water 10. By this method, sterilized water having pH highest in the presence ratio of hypochloric acid having strong sterilizing power is obtained only by adding hydrochloric acid of low concn. without using hydrochloric acid of high concn. in dilution water. If necessary, dilution water and hydrochloric acid are added to electrolytic water corresponding to a water amt. to change electrolytic water to sterilized water to use the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sterilizing water production apparatus for obtaining sterilizing water containing hypochlorous acid used for washing food, tableware, hand washing, washing medical equipment, etc. by electrolysis, and a method for producing the sterilizing water. It is about.

[0002]

2. Description of the Related Art Conventionally, a commercially available concentrated sodium hypochlorite solution (N) has been used for sterilizing and disinfecting foods such as vegetables, seafood, meats, various processed products, and processing equipment and filling containers for these foods.
(aClO) is diluted and washed.

Since a commercially available concentrated sodium hypochlorite solution is usually produced by blowing chlorine gas into a caustic soda solution, the effective chlorine concentration is about 8 to 13%. The pH of this solution improves the stability of sodium hypochlorite,
It is extremely high, usually with a strong alkali of 13 or more, and very difficult to handle.

Meanwhile, when the sodium hypochlorite diluted with _{water, NaCl0 + H 2 0 → HClO} + NaOH , and the hypochlorous acid (HClO) is produced.

Furthermore, it is known that hypochlorous acid becomes HClO → H ⁺ + ClO ⁻ , and its existing form changes depending on pH.

On the other hand, recently, a salt solution having a constant concentration is electrolyzed in a diaphragm electrolytic cell in which an anode and a cathode are arranged to generate a pH of 2.5 to 3 from the anode chamber.
Some acid water is used as sterilizing water.

[0007]

The sterilizing effect of sterilizing water differs depending on the amount of residual chlorine in the liquid, and the residual chlorine changes its existing form depending on the pH of the water. When a commercially available concentrated sodium hypochlorite is diluted, the pH becomes 7 or more. If the residual chlorine concentration is the same, most hypochlorous acid changes to the ionic form (ClO ⁻ ) at high pH, so the bactericidal power is significantly reduced compared to the case of high hypochlorous acid (HClO). To do. On the other hand, if the pH is too low as in acidic water, chlorine gas is generated more often and it becomes difficult to maintain the residual chlorine amount. In addition, chlorine gas may leak even when sterilized water is stored in a tank.

That is, it is necessary to control the pH to 4 to 7 and maximize the abundance of hypochlorous acid, which has a high bactericidal power, to effectively bring out the bactericidal power.

On the other hand, the method for producing sterilized water by diaphragmless electrolysis will be explained. When a saline solution having a constant concentration is electrolyzed in a diaphragmless electrolytic cell having an anode and a cathode, chlorine ions become chlorine gas near the anode. , It dissolves in water and becomes hypochlorous acid. In the vicinity of the cathode, caustic soda and hydrogen gas are generated due to the reaction between sodium ions and water.

Anode side: 2Cl ⁻ → Cl ₂ + 2e ⁻ Cl ₂ + H ₂ O → HClO + HCl Cathode side: 2Na ⁺ + 2H ₂ O + 2e ⁻ → 2NaOH + H ₂ At this time, the abundance ratio of hypochlorous acid changes depending on pH.

Particularly in the case of a non-diaphragm electrolytic cell, the pH of the entire electrolytic cell is weakly alkaline because there is no diaphragm separating the anode and the cathode. Here, even if the obtained electrolyzed water is diluted with ordinary tap water (pH of about 7) to obtain a predetermined pH (weakly acidic pH of 4 to 7 after dilution), the pH does not become 7 or less. Of course, when diluted with a very large amount of water, which is several tens of thousands times or more, the pH approaches 7, but the effective residual chlorine concentration also diminishes to the point where it cannot be used for sterilization.

Therefore, an object of the present invention is to produce sterilizing water having a pH at which chlorine gas is hardly generated during the production of sterilizing water and the presence of hypochlorous acid having a strong sterilizing power is the highest. It is intended to provide a sterilizing water manufacturing apparatus and a manufacturing method.

[0013]

A sterilized water production apparatus according to the present invention comprises a diaphragmless electrolytic cell for electrolyzing an electrolytic solution in which sodium chloride is added to water, and electrolyzed water obtained by electrolysis at a desired pH. And the dilution water prepared in (1), wherein hydrochloric acid is added to the dilution water.

The method for producing sterilized water according to the present invention is
It comprises a step of electrolyzing an electrolytic solution in which sodium chloride is added to water in a diaphragmless electrolytic cell, and a step of adjusting the electrolyzed water obtained by electrolysis to a desired pH with diluting water and hydrochloric acid. Characterize.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION When saline having a constant concentration is electrolyzed in a diaphragmless electrolytic cell having an anode and a cathode,
When the generated electrolyzed water having a pH of 9.0 and a liquid amount of 20 ml / min is diluted with a dilution water having a pH of 7.0 and a water amount of 1.0 l / min, the diluted pH is pH = −log [H ⁺ ] = −log10 ⁻¹⁴ / [OH ⁻ ] = 14 + log [(10 ⁻⁵ × 20/1000 + 10 ⁻⁷ ) × (1000/1020)] = 14 + log [2.94 × 10 ⁻⁷ ] = 7.5 [H ⁺ ]: Hydrogen ion concentration ^{(mol / l) [OH -} ]: hydroxyl ion concentration (mol / l) next, pH it can be seen that not below 7.0.

PH 6.0 obtained by adding hydrochloric acid to tap water as dilution water
If water of 1.0 l / min is used, the pH after dilution will be
Can be calculated as follows.

Hydroxyl ion amount (mol / min) of electrolyzed water = 10 ⁻⁵ × 20/1000 = 2 × 10 ⁻⁷ Hydrogen ion amount of diluted water (mol / min) = 10 ⁻⁶ × 1000/1000 = 10 ^{− 6 The} amount of hydrogen ions after dilution (mol / min) = 10 ⁻⁶ −2 × 10 ⁻⁷ = 8 × 10 ⁻⁷ , so the pH after dilution is pH = −log [H ⁺ ] = − log [ 8 × 10 ^-7 × 1000/1020] =-log [7.84 × 10 ^-7 ] = 6.1, which means that hypochlorite with strong bactericidal activity can be obtained by adding low concentration hydrochloric acid to dilution water without using high concentration hydrochloric acid. Sterilized water having a pH with the highest abundance of chloric acid is obtained.

Further, in the case of the present invention, the pH of the electrolyzed water obtained by electrolysis is 8 to 9, and the handling in the manufacturing process is extremely easy. Then, when necessary, depending on the amount of water, it can be used by changing it to sterilizing water by adding diluting water and hydrochloric acid to the electrolyzed water, and when sterilizing water is required, it is desired by diluting water and hydrochloric acid. It can also be obtained as sterilized water.

The desired pH in the present invention means the pH
Means a range of 4 to 7.

[0020]

EXAMPLE A sterilizing water production apparatus according to the present invention will be described in detail with reference to a specific example.

FIG. 1 is an explanatory view showing an embodiment of a sterilizing water producing apparatus according to the present invention.

In the figure, 1 is a non-diaphragm electrolytic cell, 2 is an anode, 3 is a cathode, 4 is raw water which is dilution water, and 5 is an electrolytic solution. 6 is a direct current power source for electrolysis, 7 is a constant flow pump for introducing the electrolytic solution into the electrolytic cell, 8 is an aqueous hydrochloric acid solution, and 10 is sterilizing water.

Water containing 3.0% of sodium chloride as an electrolytic solution 5 was added to an electrolytic cell 1 using an electrode having titanium coated with platinum / iridium as an anode 2 and an electrode having platinum plated with titanium as a cathode 3. The flow rate 15
Distribute at ml / min, and use DC power supply 6 for voltage 3 V, current
Electrolyzed at 6 A.

Electrolyzed electrolytic solution, that is, electrolyzed water,
Dilute with a mixed solution (pH 6.0) in which 0.1 mM hydrochloric acid aqueous solution 8 was added at 10 ml / min to 4 ml of raw water (here, tap water, pH 7.0) with a flow rate of 1.0 l / min. Chlorine concentration 50ppm
Sterilized water 10 of was obtained.

Next, the conventional method, that is, using the electrolytic solution 5 and the electrolytic cell 1 having the above-mentioned constitution, the electrolyzed water is diluted with the raw water 4 (here, tap water, pH 7.0) having a flow rate of 1.0 l / min, and the residual water is left. The chlorine concentration was 50 ppm, but the pH was 7.5, and only water with a small bactericidal effect was obtained.

That is, the sterilizing water according to the present invention has the same residual chlorine concentration as the conventional sterilizing water, but it has a high abundance of hypochlorous acid, so that it has a strong sterilizing power. Further, in the case of the present invention, the pH can be adjusted with a low concentration of hydrochloric acid, so that its handling is easy.

[0027]

The apparatus for producing sterilized water according to the present invention comprises a diaphragmless electrolytic cell for electrolyzing an electrolytic solution in which sodium chloride is added to water, and electrolyzed water obtained by electrolysis at a desired pH.
And the dilution water prepared in (1), wherein hydrochloric acid is added to the dilution water.

The method for producing sterilized water according to the present invention is
It comprises a step of electrolyzing an electrolytic solution in which sodium chloride is added to water in a diaphragmless electrolytic cell, and a step of adjusting the electrolyzed water obtained by electrolysis to a desired pH with diluting water and hydrochloric acid. Characterize.

According to the present invention, chlorine gas is hardly generated during the sterilizing water production, and by adding hydrochloric acid to the diluting water, the sterilizing agent has a pH with the highest abundance of hypochlorous acid having a strong sterilizing power. Water is obtained and its industrial value is extremely high.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of an apparatus for producing sterilizing water according to the present invention.

[Explanation of symbols]

 1 Non-diaphragm electrolysis tank 2 Anode 3 Cathode 4 Raw water 5 Electrolyte 6 DC power supply 7 Constant flow pump 8 Hydrochloric acid solution 9 Constant flow pump 10 Sterilizing water

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Kawamura 1 Kinoshoin Nishinosho Ino no Babacho, Minami-ku, Kyoto City Japan Battery Co., Ltd. Babacho No. 1 Japan Battery Co., Ltd.

Claims (2)

[Claims] 1. A non-diaphragm electrolytic cell for electrolyzing an electrolytic solution in which sodium chloride is added to water, and diluting water for adjusting electrolyzed water obtained by electrolysis to a desired pH. The sterilized water production apparatus is characterized in that hydrochloric acid is added to the. 2. A step of electrolyzing an electrolytic solution in which sodium chloride is added to water in a diaphragmless electrolytic cell, and a step of adjusting the electrolyzed water obtained by the electrolysis to a desired pH with diluting water and hydrochloric acid. And a method for producing sterilized water, comprising: