JPH1043763A - Ph drop preventive device of electrolyte water producing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that the sterilization effect of electrolytic water is lowered by the fall of pH by disposing a gas introducing device into the electrolytic water to be produced by a device which is provided with an anode and cathode across a selective ion exchange membrane and produces the electrolytic water by subjecting a soln. contg. chlorine to an electrolytic treatment. SOLUTION: The production section A for producing the electrolytic water pours raw water to an electrolytic cell 15 by opening a valve 11 and forms acidic water by impressing a positive voltage on the electrode 13 and alkaline water by impressing a negative voltage on the electrode 14. The dissolution permissible amt. of the gaseous chlorine dissolved in the electrolytic water is lowered by the gas sent into the electrolytic water via a valve 43 from a supply gas source 44, by which the gaseous chlorine exceeding the permissible amt. is released to lower the chlorine ion concn. and hydrogen ion concn. The introduction of the gas into the electrolytic water is executed by measuring the pH of the electrolytic water with a pH electrode 40 installed in the electrolytic cell 15 and controlling a valve 43 according to the pH value determined by a pH meter 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the sterilization of various instruments and hands of workers in laboratories handling living organisms, disinfection in hospitals, etc., disinfection in plant cultivation, etc. The present invention relates to a method for producing acidic electrolyzed water having a disinfecting effect such as a bactericidal property and an antibacterial property used as a disinfectant for use in veterinary and livestock industries, public places requiring sanitation, places requiring disinfection, and the like. The present invention relates to an apparatus for preventing a decrease in pH value of electrolyzed water produced by a production apparatus.

[0002]

2. Description of the Related Art It is known that when electrolyzing distilled water or an electrolyte solution, acidic electrolyzed water is generated on the anode side and alkaline electrolyzed water is generated on the cathode side. Generally, alkaline electrolyzed water is called alkaline water, alkaline ionized water or the like, while acidic electrolyzed water is called acidic water, strongly oxidized water, strongly acidic water, super oxidized water, or the like. Conventionally, it has been empirically known that this electrolyzed water may have bactericidal or antibacterial properties. Utilizing this disinfecting effect such as bactericidal and antibacterial properties, the use as sterilizing water is examined.
Public equipment that requires medical care, food industry, food and beverage industry, veterinary / livestock industry, sanitation, etc. It may be used as a disinfectant to be used in places or places that require sterilization.

[0003] Electrolyte solutions include chlorine, bromine and iodine.
It is a solution containing a halogen group element having a high electronegativity that easily becomes a valent anion. An electrolyte solution is injected into an electrolytic cell in which an anode and a cathode are interposed with an ion-permeable membrane interposed therebetween, and a voltage is applied between the anode and the cathode to electrolyze the electrolyte solution. Water is generated, and alkaline electrolyzed water is generated on the cathode side.

[0004] The applicant of the present patent application has examined the sterilizing properties of acidic electrolyzed water and found that there is a correlation between the sterilizing effect of electrolyzed water and the concentration of hypochlorous acid. Has confirmed that it is mainly caused by hypochlorous acid contained in electrolyzed water, and has filed a patent application for a method of producing electrolyzed water having a bactericidal effect. Furthermore, the applicant of the present patent application has also filed a patent application for a method for quantitatively measuring the sterilizing effect of sterilizing water (Japanese Patent Application No. Hei 7-2667).
No. 7).

[0005]

When acidic water is produced by an electrolysis apparatus, the composition of the produced electrolytic water depends on the voltage applied to the electrodes, the state of the electrodes, the composition of the raw water, the temperature of the raw water, and the like. Affected by various electrolysis conditions. The concentration of hypochlorous acid in the electrolyzed water, which is the main source of the sterilization effect of the manufactured electrolyzed water, changes according to the pH value, and the hypochlorous acid in the electrolyzed water whose pH value has dropped too low is changed. Has a problem that the bactericidal effect is reduced.

[0006] In the electrolytic cell of the electrolyzed water producing apparatus, the formula (1)
As shown in the equation, chlorine gas Cl ₂ and water H ₂ O are in equilibrium with hypochlorite HClO, hydrogen ions H ⁺ and chlorine ions Cl ^−, and between their concentrations, There are relationships shown.

[0007]

(Equation 1) Here, when the pH in the electrolytic cell decreases, the hydrogen ion concentration [H ⁺ ] increases. As the hydrogen ion concentration [H ⁺ ] increases, the chloride ion concentration [Cl ⁻ ] increases. Equation (2)
If the ion product K is constant in the above, the hydrogen ion concentration [H ⁺ ] and the chloride ion concentration [Cl ⁻ ] increase,
The hypochlorous acid concentration [HClO] decreases. Since the sterilizing effect of the electrolyzed water is mainly caused by hypochlorous acid contained in the electrolyzed water, if the hypochlorous acid concentration [HClO] in the electrolyzed water decreases, the sterilizing power of the electrolyzed water decreases.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problem that the sterilizing effect of electrolyzed water is reduced by such a decrease in pH value, and to prevent the sterilizing effect of electrolyzed water from being lowered by increasing the pH value. And

[0009]

An apparatus for preventing pH decrease of an electrolyzed water producing apparatus according to the present invention has an anode and a cathode with a selective ion exchange membrane interposed therebetween, and electrolyzes a solution containing chlorine to produce electrolyzed water. An electrolyzed water producing apparatus having an electrolyzing tank to be produced, comprising a gas introducing device for injecting a gas that does not cause a chemical reaction with a gas component dissolved in the electrolyzed water into the electrolyzed water produced by the electrolyzed water producing apparatus. is there.

The gas introducing device of the present invention injects a gas that does not cause a chemical reaction with a gas component dissolved in the electrolytic water into the electrolytic water produced by the electrolytic water producing device. Usually, there is a predetermined limit value for the concentration of a gas component that can be dissolved in electrolyzed water. When a gas is sent from outside into this electrolytic water, the gas component sent in reduces the allowable dissolution amount of the gas component dissolved in the electrolytic water. The excess is vaporized and released outside the electrolytic water.

When a gas such as nitrogen gas or air is fed into the electrolyzed water by the gas introduction device of the present invention, chlorine gas Cl _{2 in the} electrolyzed water is released by the sent gas, and the above formula (1) The movement from the right term to the left term progresses,
Chloride ion concentration [Cl ^-] and the hydrogen ion concentration [H ^+] is reduced. Thus, an increase in the hydrogen ion concentration [H ⁺ ] of the electrolyzed water can be prevented, and a decrease in the concentration of HClO hypochlorite can be prevented.

The gas introduction device of the present invention further includes a device for measuring the pH of the electrolyzed water, and controls the gas to be introduced into the electrolyzed water according to the measured pH value. Prevention of pH drop can be performed automatically.

The gas introduced by the gas introduction device can be nitrogen gas or air, and a supply gas source such as a nitrogen gas cylinder or an air compressor disposed outside the electrolytic cell can be used.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a pH lowering prevention device of the electrolyzed water production apparatus of the present invention. The pH reduction preventing device of the electrolyzed water production apparatus shown in FIG. 1 includes a production part A for producing electrolyzed water, a measurement part B for measuring the hypochlorous acid concentration of the produced electrolyzed water, and a pH for adjusting the pH of the electrolyzed water. And a lowering prevention portion C. In FIG. 1, each part A, B, C is indicated by a dashed rectangle.

The measuring portion B is an internal reservoir type configuration in which the concentration of hypochlorous acid in the electrolytic water is measured by absorbance. As a configuration of the measurement portion B, a flow type configuration (not shown) may be used.

In the production part A for producing electrolyzed water, the electrolytic cell 15 is separated into two chambers with a selective ion exchange membrane 16 interposed therebetween, and an electrode 13 and an electrode 14 are provided in each chamber.
A DC voltage source 12 is connected to the electrodes 13 and 14, and a positive voltage is applied to the electrode 13 to form an anode.
A negative voltage is applied to the electrode 14 to form a cathode. Tubes for extracting electrolyzed water are installed from the anode side and the cathode side, respectively. In addition, a solution containing chlorine, such as tap water, is injected into the electrolytic cell 15 through the valve 11.
If the raw water to be injected into the electrolytic tank 15 contains chlorine, it is used as it is, and if the chlorine concentration is low, NaCl is used.
Use a solution to which are added.

In the hypochlorous acid concentration measurement part B, reference numeral 27 denotes a spectrophotometer for measuring the hypochlorous acid concentration of the generated electrolyzed water by absorbance. A measuring cell 28 is provided for mixing with the solution. This spectrophotometer 27 is a normal measuring instrument 30
And a data processing means 31 for processing data obtained by the measuring instrument 30.

The measuring cell 28 has various valves 21 and
Blank water, electrolyzed water, standard solution 25,
And an aqueous caustic soda solution 26 can be injected. Electrolyzed water is injected into the measurement cell 28 via the four-way valve 21 and the four-way valve 22. The standard solution 25 is a four-way valve 2
2 into the measuring cell 28. Further, the aqueous caustic soda solution 26 is injected into the measurement cell 28 via the valve 23. The solution after the measurement is supplied from the measurement cell 28 to the valve 2.
4 is drained. Further, the electrolyzed water from the electrolysis tank 15 can be taken out through the four-way valve 21 and the valve 20.

The pH lowering prevention portion C includes a pH electrode 40 for measuring the pH value of the electrolyzed water in the electrolytic cell 15 and the pH electrode 40 for measuring the pH value.
The apparatus includes a pH meter 41 for measuring a pH value based on a measurement output of the electrode 40, a supply gas source 44 for introducing gas into the electrolytic water, a control device 42 for controlling the introduced gas, and a valve 43. . The controller 42 controls the opening and closing of the valve 43 according to the pH value from the pH meter 41, and controls the introduction of gas into the electrolyzed water. This control is performed, for example, by determining that the measured pH value has become equal to or less than the set value, opening the valve 43 based on this determination, and introducing gas from the supply gas source 44 into the electrolyzed water. As the gas to be introduced, for example, nitrogen gas or air can be used, and a gas that does not cause a chemical reaction with a gas component such as chlorine gas contained in the electrolyzed water is desirable. Further, as the supply gas source 44, a nitrogen gas cylinder or an air compressor can be used.

The operation of each part of A, B and C will be described below. In the manufacturing part A for producing the electrolyzed water, the valve 11 is opened, raw water such as tap water is poured into the electrolysis tank 15, and a DC voltage is applied for a predetermined time to perform an electrolysis treatment to generate electrolyzed water. Acidic water is generated at the electrode 13 to which a positive voltage is applied, and alkaline water is generated at the electrode 14 to which a negative voltage is applied.

When a nitrogen gas or air gas is fed into the electrolyzed water from the supply gas source 44 via the valve 43 in the pH lowering prevention portion C, the dissolved gas dissolves the chlorine gas Cl 2 dissolved in the electrolyzed water. The allowable amount is reduced, and chlorine gas Cl ₂ exceeding the allowable amount is released. As a result, the movement from the right term to the left term in equation (1) proceeds, and the chloride ion concentration [Cl ⁻ ] and the hydrogen ion concentration [H ⁺ ] decrease. Thus, an increase in the hydrogen ion concentration [H ⁺ ] of the electrolyzed water can be prevented, and a decrease in the concentration of HClO hypochlorite can be prevented.

The gas can be introduced into the electrolyzed water arbitrarily or in accordance with the pH value in the electrolyzed water. When introducing a gas in accordance with the pH value in the electrolyzed water, the pH of the electrolyzed water is measured by a pH electrode 40 provided in the electrolysis tank 15, and the measured output is measured by a pH meter 41.
The pH value is obtained by the control device 42 according to the pH value.
By controlling the valve 43.

The control by the control device 42 is performed, for example, by setting an allowable pH value,
Compared to the H value, the valve 43
Is opened, and a gas is introduced from the supply gas source 44 into the electrolyzed water. The allowable pH value can be set arbitrarily according to the characteristics of the electrolytic water to be produced.

The operation of the measuring portion B for measuring the hypochlorous acid concentration of the electrolyzed water will be described below with reference to one method for measuring the hypochlorous acid concentration by the caustic soda addition method. One method of measuring hypochlorous acid concentration by the caustic soda addition method is to replace hypochlorous acid in the measurement solution with hypochlorite ion and measure the absorbance of the concentration of this hypochlorite ion at a single wavelength. This is a measuring method for measuring the concentration of hypochlorous acid. When performing concentration measurement by absorbance, it is necessary to perform measurement in the state of hypochlorite ion, so after alkalizing hypochlorous acid and replacing it with hypochlorite ion, this hypochlorite ion The concentration of hypochlorous acid is determined by measuring the concentration.
Hypochlorous acid and hypochlorite ion are in an equilibrium state as shown by the formulas (3) and (4). In an aqueous solution, hypochlorous acid and hypochlorite ion are present depending on pH. The ratio is fixed.

[0025]

(Equation 2) Both hypochlorous acid and hypochlorite ion have a bactericidal effect, but generally hypochlorous acid has a greater bactericidal effect than hypochlorite ion. As shown in the formula (4), the presence ratio of hypochlorous acid is high in the acidic region. On the contrary,
When this solution is adjusted to, for example, an alkaline region having a pH of 9.4 or more, the relative abundance of hypochlorous acid becomes 1/100 or less, and hypochlorous acid is substantially replaced with hypochlorite ion. Therefore, by measuring the concentration of hypochlorite ion obtained by alkalizing hypochlorous acid, hypochlorous acid can be measured.

Therefore, as a measurement of the concentration of hypochlorous acid, the concentration of hypochlorous acid is measured by a caustic soda addition method. In addition, it can also measure by changing to alkalinity using an alkaline solution, such as potassium hydroxide, instead of caustic soda aqueous solution (sodium hydroxide aqueous solution).

First, the absorbance of hypochlorite ion is measured for blank water and a standard solution containing no hypochlorous acid, and a two calibration curve is created based on the absorbance.

Next, an electrolytic treatment is performed in an electrolytic cell to generate acidic electrolyzed water, which is mixed with an aqueous caustic soda solution 26 in a measuring cell 28 to convert hypochlorous acid in the acidic electrolyzed water into hypochlorite ions. The absorbance of the solution in the measurement cell 28 is determined by the spectrophotometer 27, and the concentration of hypochlorous acid is determined based on the two calibration curves determined by the data processing means 31. Thereby, the hypochlorous acid concentration of the acidic electrolyzed water in the electrolytic cell is measured.

[0029]

As described above, according to the present invention,
By increasing the pH value, it is possible to prevent a decrease in the sterilizing effect of the electrolyzed water.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for preventing a decrease in pH of an electrolyzed water producing apparatus according to the present invention.

[Explanation of symbols]

 A Production part for producing electrolyzed water B Measurement part for measuring hypochlorous acid concentration of electrolyzed water C pH prevention part 11, 20, 23, 24, 43 Valve 21, 22 Four-way valve 12 DC voltage source 13, 14 Electrode 15 Electrolyzer 16 Selective ion exchange membrane 25 Standard solution 26 Caustic soda aqueous solution 27 Spectrophotometer 28 Measurement cell 29 Flow cell 30 Measurement instrument 31 Data processing unit 32 pH electrode 33 pH meter 34 Filter 40 pH electrode 41 pH meter 42 Controller 44 Supply Gas source

Continued on the front page (51) Int.Cl. ⁶ Identification number Reference number in the agency FI Technical display location C02F 1/50 550 C02F 1/50 550L 560 560F

Claims (3)

[Claims] 1. An electrolyzed water producing apparatus comprising: an anode and a cathode with a selective ion exchange membrane interposed therebetween; A gas introduction device for injecting a gas that does not cause a chemical reaction with a gas component dissolved in the electrolyzed water into the electrolyzed water produced by the method described above, wherein the pH of the electrolyzed water production device is reduced. 2. The apparatus according to claim 1, wherein said gas introducing device includes a pH measuring device for electrolyzed water, and controls gas introduction according to the measured pH value. . 3. The apparatus according to claim 1, wherein the gas is nitrogen gas or air.