JP2000005757A - Economical production of electrolytic sterilizing water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an excessive build-up of voltage without increasing a running cost by passing a hydrochloric acid aq. soln. to which sodium chloride is not added to a diaphragmless electrolytic cell having double pole type electrode, electrolyzing the passed hydrochloric acid aq. soln. and collecting the electrolyzed water. SOLUTION: A main piping 2 letting the water flow is provided at a water source 1, and a solenoid valve 3 and a fixed delivery valve 4 are provided at the main piping 2 and also the diaphragmless electrolytic cell 5 is provided at a branched pipe 2a branched from the main piping 2. Then the hydrochloric acid C having 21% concn. and to which sodium chloride is not added is stored in a hydrochloric acid vessel 6, and the water is made to flow to the main piping 2 from the water source 1 by a flow rate of 1200 l/h, and the water is made to flow by branching to the branched pipe 2a branched from the main piping 2 by a flow rate of 1.2 l/h, and simultaneously the hydrochloric acid C is poured into the branched pipe 2a from the hydrochloric acid vessel 6 by a flow rate of 100 ml/h and the hydrochloric acid aq. soln. is passed through the diaphragmless electrolytic cell 5. In this way, the device is operated on a fixed condition without increasing the running cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an economical method for producing electrolytic sterilizing water. More specifically, the present invention relates to a method for producing electrolytic sterilizing water in which an aqueous hydrochloric acid solution is passed through a non-diaphragm electrolytic cell to perform electrolysis, and a large amount of electricity is produced with a high power effect despite employing a bipolar electrode. The present invention relates to a highly economical method for producing electrolytic sterilizing water which can generate chlorine.

[0002] In the present invention, "electrolytic sterilizing water" means sterilizing water in which water containing chlorine ions is electrolyzed and chlorine gas generated by the electrolysis is dissolved. The “power effect” means the amount of chlorine gas generated per power consumption.

[0003]

2. Description of the Related Art In recent years, it has been known that electrolyzed water obtained by electrolysis of various solutions has a bactericidal effect, and such electrolyzed germicidal water has been applied to various sterilizations and disinfections. Shiyoko Shiba et al., "Handbook of Strong Electrolyzed Water", Medical Information Company, 1995).

[0004] As a conventional method for producing electrolytic sterilizing water, for example, a technique disclosed in Japanese Patent Application Laid-Open No. 1-180293 is known. In this technique, sodium chloride-added water is passed through an electrolytic cell with a diaphragm, which is electrolyzed, and the strongly acidic water generated on the anode side is obtained as electrolytic sterilizing water. Water has a pH of 1.5 or more and 3.2 or less, and is said to have a higher bactericidal effect than a simple low pH solution.

In the technique disclosed in Japanese Patent No. 2627100, water to which sodium chloride is added and water to which hydrochloric acid is added are mixed and electrolyzed by a diaphragm-free electrolytic cell. In some cases, the water to which sodium chloride is added is an indispensable additive for increasing the efficiency of electrolysis.

Further, the present inventors have invented a technique for obtaining an electrolytic sterilizing water by passing a hydrochloric acid aqueous solution containing substantially no sodium chloride through a non-diaphragm electrolytic cell to electrolyze the electrolytic solution. Patent Application No. 309920 has already been filed (hereinafter referred to as prior art).

Electrolytic sterilizing water produced by these techniques has a higher sterilizing effect even at a low chlorine concentration than, for example, chlorinated water prepared by dissolving sodium hypochlorite in water. In addition, since it is not necessary to finely adjust the concentration each time it is used, it is suitable as a bactericide.

[0008] Water used as a raw material of electrolytic sterilizing water (hereinafter referred to as raw water) is water containing chlorine ions, such as an aqueous solution of sodium chloride or an aqueous solution of hydrochloric acid. Such raw water is electrolyzed, chlorine gas is generated by the action of electrolytic oxidation, and the generated chlorine gas is dissolved in water to generate hypochlorous acid in the water. Electrolytic sterilizing water exhibits a bactericidal effect by the action of this hypochlorous acid.

[0009] On the other hand, when an electrode is generally constituted by a plurality of electrode plates and energized in an electrolytic cell, two types of energization methods, a monopolar type and a bipolar type, are conventionally known. (The Electrochemical Association, edited by the Electrochemical Handbook,
(Page 510, Maruzen, 1954).

The monopolar type is a type in which all of the electrode plates are either a cathode or an anode, and the bipolar type is, for example, a structure in which a plurality of electrodes are insulated from each other at regular intervals and overlapped. And between the electrode plate connected to the anode of the power supply and the electrode plate connected to the cathode of the power supply, there is at least one electrode that is not connected to any of the electrodes (hereinafter referred to as an intermediate electrode). (Hereinafter, an electrode performing a monopolar energization method is referred to as a monopolar electrode, and an electrolytic cell provided with the monopolar electrode is referred to as a monopolar electrolytic cell. The electrode for conducting the current is referred to as a bipolar electrode, and the electrolytic cell provided with the bipolar electrode is referred to as a bipolar electrolytic cell.

In general, in the production of electrolytic sterilizing water, from the viewpoint of economy, as much chlorine as possible is generated in the electrolysis step, and a small amount of water having a high chlorine concentration is produced.
Thereafter, it is desirable to appropriately dilute the solution and use it as electrolytic sterilizing water. If only a small amount of water having a high chlorine concentration is produced, the size of the electrolytic cell can be reduced, which is advantageous in terms of capital investment, production cost, energy efficiency and the like. For this purpose, it is desirable to use raw water having a chlorine ion concentration as high as possible to obtain electrolytic sterilizing water having a high effective chlorine concentration.

Although the raw water having a high chlorine ion concentration has a high electric conductivity, it has been said that the following advantages are obtained when the bipolar electrolytic cell is used to electrolyze the water. .

(1) When a constant voltage power supply is used When the electrolysis is performed under a constant voltage condition, the current value increases if the electric conductivity of the raw water is high, and the increase in the current value causes the electrode to be driven. There is a problem that the life is shortened. However, in the case of a bipolar electrolytic cell, the resistance of the electrolytic system can be increased, so that an increase in the current value can be suppressed. Therefore, there is no problem that the life of the electrode is shortened.

(2) When a constant current power supply is used When the electrolysis is carried out under a constant current condition, if the electric conductivity of the raw water is high, the voltage value is reduced, and it is necessary to operate under different electrolysis conditions. I will be forced. However, in the case of a bipolar electrolytic cell, since the resistance of the electrolytic system can be changed, a decrease in the voltage value can be avoided. Therefore, electrolysis under certain conditions can be ensured.

(3) Electrolysis under general conditions that are neither constant voltage nor constant current As the chlorine ion concentration of the raw water increases, the current value and / or the voltage value fluctuates. By adopting the above, it is possible to set operating conditions that can maintain the same current value or voltage value only by adding the intermediate electrode.

[0016]

However, conventionally,
Bipolar electrolyzers have been used for producing chlorine or caustic soda on an industrial scale (see "Soda and Chlorine", Vol. 26, No. 4, No. 112). Page, 1975
Year), it was not employed in the process of producing electrolytic sterilized water.

The reason for this is that, in general, when a bipolar electrolytic cell is employed, the amount of chlorine generated increases as the number of intermediate electrodes increases, but the amount of chlorine generated per unit power decreases. This is because it has been known that the running cost increases after all (that is, the power effect decreases).

In general, since a bipolar electrolytic cell is equivalent to one in which a plurality of monopolar electrodes are connected in series, the voltage to be applied tends to be high although the current capacity is small (Japan Corporation). Chemical Society, "Chemical Handbook", page 99
J. Maruzen Co., 1965). In the production of the electrolytic sterilizing water, the concentration of the raw water is extremely low as compared with other technical fields, and thus the increase in the voltage is extremely large. In particular, in a system using a diaphragm type electrolytic cell, the number of diaphragms increases as does the number of electrodes. Therefore, the voltage rises significantly and the electrolytic effect is greatly reduced. Furthermore, since it is necessary to separate out the anode water and the cathode water, the structure becomes extremely complicated. Therefore, in the technical field of electrolytic sterilizing water, it has been considered difficult to use a bipolar electrolytic cell in practical use.

After all, despite the great advantages of the bipolar electrolyzer in the past, the running cost was increased,
The problem of excessive rise in voltage could not be solved, and it was not adopted in the technical field of electrolytic sterilization water. Even if it was adopted, the driver had to drive in preparation for an increase in running costs.

An object of the present invention is to make it possible to employ a bipolar electrolytic cell without increasing running costs and suppressing an excessive increase in voltage, and to obtain the advantages of the bipolar electrolytic cell. An object of the present invention is to provide a method for producing electrolysis sterilized water which can be enjoyed effectively and can be carried out with high economic efficiency.

[0021]

According to the present invention, there is provided a diaphragm-free electrolytic cell having a bipolar electrode, in which a hydrochloric acid aqueous solution containing substantially no sodium chloride is passed, and the passed hydrochloric acid is passed through. An economical method for producing electrolytically sterilized water by electrolyzing an aqueous solution and collecting electrolyzed water.

In the present invention, the electrolyzed water may be collected after diluting the electrolyzed water, and the electrolyzed water may be collected after adding a neutralizing agent. , In a desirable mode.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first feature of the method of the present invention is that the hydrochloric acid aqueous solution as a raw material is a hydrochloric acid aqueous solution to which substantially no sodium chloride is added.

Such an aqueous hydrochloric acid solution of the present invention comprises:
For example, it is adjusted by adding hydrochloric acid to water containing substantially no sodium chloride. Here, “water” is tap water, groundwater, underground water, demineralized water, distilled water, purified water (RO water, membrane-treated water), a mixed water thereof, or the like, which is substantially free of sodium chloride. Means

"Substantially no addition of sodium chloride"
Means that there is no artificial addition of sodium chloride. In this case, a small amount of sodium chloride naturally contained in water as a raw material of the aqueous hydrochloric acid solution is not considered.

The fact that sodium chloride is not added to the aqueous hydrochloric acid solution means that the sodium ion concentration of the aqueous hydrochloric acid solution does not exceed the sodium ion concentration contained in the "water". For example, such “water” generally has a sodium ion concentration of 200
ppm or less, the aqueous hydrochloric acid solution of the present invention also
The sodium ion concentration is 200 ppm or less. still,
In the present invention, it is desirable not to add not only sodium chloride but also alkali metal chloride as a whole.

The concentration of hydrogen chloride in the aqueous hydrochloric acid solution is preferably at least 0.01% (by weight, hereinafter the same unless otherwise specified) in order to cause an appropriate reaction.
In particular, it is recommended that the content be 0.1% or more. However, when pursuing economy, the concentration of hydrogen chloride is desirably 1.0% or more and 21.0% or less. That is, if the concentration of hydrogen chloride is 1.0% or more, an industrially stable reaction can be obtained. If the concentration is 21.0% or less, no smoke is generated at room temperature, and storage and handling are performed. This is desirable in that respect.

After passing such an aqueous hydrochloric acid solution through a non-diaphragm electrolytic cell, a current is applied to both the positive and negative electrodes to perform electrolysis. In addition, the non-diaphragm electrolytic cell is an electrolytic cell having no diaphragm.

The second feature of the method of the present invention is that the electrolytic cell is a non-diaphragm electrolytic cell having a bipolar electrode. That is, in the technical field of the conventional electrolytic sterilizing water, a monopolar electrolytic cell has been exclusively used. This is because, as described above, when a bipolar electrolytic cell is employed, it is considered that the power effect is reduced, the running cost is increased, and the voltage is excessively increased.

However, the present invention has the first feature of passing a hydrochloric acid aqueous solution to which substantially no sodium chloride is added, so that the power effect is reduced despite the use of a bipolar electrolytic cell. Therefore, the running cost does not increase and the voltage does not excessively increase. This is the fact that the present inventors have discovered for the first time.

As described above, in the present invention, economical production of electrolytic sterilizing water can be performed while maximizing the advantages of the bipolar electrolytic cell.

A preferred embodiment of the present invention is that the electrolyzed water is collected after dilution.

As described above, in the production of electrolytic sterilizing water, it is generally desirable from the viewpoint of economy to produce only a small amount of water having a high chlorine concentration and then to dilute the water appropriately. The production method of the present invention does not lower the power effect despite the use of a bipolar electrolytic cell,
Water having a high chlorine concentration can be stably and economically produced. Therefore, it is possible to reduce the size of the electrolytic cell,
This is advantageous in terms of capital investment, manufacturing cost, energy efficiency, and the like.

The sterilizing water produced by the production method of the present invention does not lose its sterilizing effect even if the effective chlorine concentration is diluted to a concentration of 1 to 2 ppm.

The present invention also has a desirable mode in which the electrolyzed water is neutralized with a neutralizing agent. When electrolytic sterilizing water having a high effective chlorine concentration is obtained by the method of the present invention, the pH of the electrolytic sterilizing water generally tends to decrease.

In general, it is known that the disinfecting power of water in which chlorine is dissolved changes depending on the pH (Fuji Techno System Co., Ltd., “Food Industry Microbiological Control Comprehensive Technical Data”, Vol. 243 pages, Showa 52
If the pH of the electrolytic sterilizing water is 6.5 or less, the sterilizing power is high, which is desirable. In addition, if the electrolytic sterilizing water is strongly acidic, there are restrictions on the place and method of use, and thus the pH of the electrolytic sterilizing water is preferably 4.0 or more.

In the present invention, the pH of the electrolytic sterilizing water is adjusted to the above-mentioned pH range as much as possible by adding a neutralizing agent. Alkaline chemicals are suitable as such a neutralizing agent, and sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate and the like can be used, but sodium hydroxide is most preferable.

By adding the above neutralization step to the present invention, the advantage of the present invention that electrolysis of high-concentration raw water to obtain high-chlorine-concentration electrolysis water is maximized. You get. When diluting the electrolyzed water, the neutralizing agent may be added before or after the dilution, but the latter is more preferable.

Next, the present invention will be described in detail with reference to test examples. Test Example 1 This test was performed to examine the effect of sodium chloride on the power effect and voltage of the electrolytic cell.

1) Preparation of Sample Hydrochloric acid (Kanto Chemical Co., Ltd., reagent grade) was added to distilled water, and a hydrochloric acid aqueous solution having a hydrogen chloride concentration of 3% was prepared to prepare a test sample.

Similarly, sodium chloride (manufactured by Wako Pure Chemical Industries, special grade reagent) was added to distilled water to prepare a 4.8% sodium chloride aqueous solution, which was used as a control sample. The above test sample and control sample have the same chloride ion concentration. The sodium ion concentration in the test data was 0.85 norm.

2) Test Method The test was performed using the apparatus shown in FIG. 2 which was made by the present inventors. FIG. 2 is a schematic diagram showing the test apparatus of the present invention. In FIG. 2, a main pipe 2 is connected from a water source 1 via a constant flow valve 3, and an outlet of the non-diaphragm electrolytic cell 5 is joined to reach an outlet 8.

The diaphragmless electrolytic cell 5 has at least one pair of a platinum-coated titanium-made anode and cathode (not shown).
An intermediate electrode can be freely inserted between the negative and positive electrodes at intervals of 3 mm. Incidentally, the effective electrode area of these electrodes was 0.24 dm ² .

The test sample or the control sample is stored in the container 6,
Each of the stored samples is supplied to a metering pump 7 (Furue-sha. RP-P).
The solution was passed through the non-diaphragm electrolytic cell 5 at a flow rate of 0.7 l / h by A). Water was supplied from the water source 1 to the main pipe 2 at a flow rate of 120 l / h.

A test sample and a control sample were sequentially electrolyzed by applying a current of 6 A to the electrodes of the non-diaphragm electrolytic cell 5 to obtain electrolytic sterilized water from the outlet 8. This electrolysis operation was repeated while changing the number of intermediate electrodes from 0 to 3. When the number of intermediate electrodes is 0, the electrode is a monopolar electrode. The voltage was adjusted so that the current value was 6 A regardless of the number of intermediate electrodes.

The obtained electrolytic sterilized water was collected, and the effective chlorine concentration was measured in a usual manner. Further, from the product of the effective chlorine concentration and the flow rate of the electrolytic sterilizing water, the amount of chlorine generated per unit time is calculated, and further, the power is calculated from the values of the supplied voltage and current, and the amount of chlorine generated is divided by the power. Thus, the amount of chlorine generated per power consumption, that is, the power effect was calculated.

3) Test results The results of this test are as shown in Table 1. In Table 1, in each of the control sample and the test sample, the amount of chlorine generated increased as the number of intermediate electrodes was increased, and the current value was kept constant by employing a bipolar electrolytic cell. It was confirmed that the amount of generated chlorine could be increased. That is, if a bipolar electrode is employed, there is an advantage that the amount of chlorine generated can be increased without shortening the life of the electrode.

On the other hand, in the control sample, the power effect decreases as the number of intermediate electrodes increases, whereas in the test sample, the power effect increases in reverse as the number of intermediate electrodes increases. It became clear. That is, when using a hydrochloric acid aqueous solution to which substantially no sodium chloride is added as a raw material, even if a bipolar electrode is employed and the number of intermediate electrodes is increased to increase the amount of generated chlorine, the power effect is reduced. There was no surprising fact that it improved.

Further, if attention is paid to the voltage value, it is clear that the test material has a lower voltage value than the control sample.

Conventionally, a bipolar electrolyzer generally has the advantage that the amount of chlorine generated can be increased without shortening the life of the electrode, but it is difficult to adopt it because the power effect is reduced and the voltage is increased. There was common sense that there was. However, as a result of this test, only when raw water to which substantially no sodium chloride is added is selected, the power effect is improved and the increase in voltage is suppressed, and the bipolar electrolytic cell is more suitable. Turned out to be.

A similar test was performed with various changes in voltage, current value, flow rate, etc., and all the same results were obtained. In addition, a similar test was conducted by mixing the control sample with the test sample, and as a result, it was found that the power effect was significantly reduced as the mixing ratio of the control sample was increased, and the addition of sodium chloride reduced the power effect. It was clear that this was the cause.

[0052]

[Table 1]

Test Example 2 This test was conducted to examine the effect of sodium chloride on the power effect and voltage of the electrolytic cell when the chlorine ion concentration of the raw water was relatively high.

1) Preparation of Sample Hydrochloric acid (special grade reagent, manufactured by Kanto Kagaku Co., Ltd.) was added to distilled water to prepare a hydrochloric acid aqueous solution having a hydrogen chloride concentration of 6.3%, which was used as a test sample.

Similarly, sodium chloride (reagent grade, manufactured by Wako Pure Chemical Industries, Ltd.) was added to distilled water to prepare a 10.0% concentration aqueous sodium chloride solution, which was used as a control sample. The test sample and the control sample have the same chloride ion concentration. However, each has a chloride ion concentration that is slightly more than twice that of the sample of Test Example 1.

2) Test method The test example 1 was repeated except that the test sample and the control sample were passed through the non-diaphragm electrolytic layer 5 at a flow rate of 6.4 ml / m, and electrolysis was performed at a current value of 3.8 A. The test was performed under the same conditions as described above. The same measurement as in Test Example 1 was performed, and the power effect was calculated. In addition, the case where the number of intermediate electrodes was 0 and the number of the intermediate electrodes were 1 were tested.

3) Test results The results of this test are as shown in Table 2. Looking at the effect of the number of intermediate electrodes in Table 2, the control sample has one intermediate electrode (in the case of a bipolar electrode) rather than zero (in the case of a monopolar electrode). It is clear that the power effect is reduced and the degree of the reduction is greater than that of Table 1 above. On the other hand, in the test sample, the power effect is improved when the number of the intermediate electrodes is one (in the case of the bipolar electrode) as compared with the case where the number of the intermediate electrodes is zero (in the case of the monopolar electrode). Further, it is clear that the degree of this improvement is larger than that of Table 1 described above.

With respect to the voltage value, the test sample had a lower voltage value than the control sample, and the results were the same as in Test Example 1.

As a result of this test, in the method of the present invention, it was found that the degree of improvement in the power effect with an increase in the number of intermediate electrodes was more remarkable as the chlorine ion concentration of the raw water was higher.

[0060]

[Table 2]

[0061]

Next, the present invention will be described in detail with reference to examples.
The present invention is not limited to the following examples.

Embodiment 1 First, an apparatus for carrying out the method for producing electrolytic sterilized water of the present invention will be described.

FIG. 1 is a schematic diagram showing an example of an apparatus for carrying out the method of the present invention. In FIG. 1, a water source 1
The main pipe 2 is provided with a solenoid valve 3 (manufactured by Ben Co., WS-12) and a constant flow valve 4 (manufactured by Nippon Flow Cell Co., Ltd., HCT-20A, 1200 l / h
Is installed. Branch pipe 2 branched from main pipe 2
A is provided with a non-diaphragm electrolytic cell 5 (made by the present inventors). Electrodes (not shown) of this diaphragmless electrolytic cell 5
Is a bipolar electrode having one intermediate electrode, and has an effective area of 2.3 dm ² . A power supply (not shown) (HK150A-5, manufactured by Nemic Lambda) is connected to the bipolar electrode.

The hydrochloric acid container 6 stores hydrochloric acid C.
Metering pump 7 (manufactured by Iwaki Corporation, EH-B10VC-100)
Hydrochloric acid C is injected into the branch pipe 2a via PR1-AE). The outlet pipe 2 b of the diaphragm-free electrolytic cell 5 joins the main pipe 2, and the end of the main pipe 2 reaches the outlet 8.

Using the apparatus having the above structure, electrolytic sterilizing water was produced in the following procedure. That is, hydrochloric acid C having a concentration of 21% is stored in the hydrochloric acid container 6, and 1200 l of water is supplied from the water source 1 to the main pipe 2.
/ H at a flow rate of / h. Water is branched into the branch pipe 2a at a flow rate of 1.2 l / h, and at the same time, the hydrochloric acid C is supplied for 100 m
The mixture was injected into the branch pipe 2 a at a flow rate of 1 / h, and an aqueous hydrochloric acid solution was passed through the non-diaphragm electrolytic cell 5.

In the non-diaphragm electrolytic cell 5, a current was passed through the bipolar electrode at a voltage of 4.5 V and a current of 10 A, and the hydrochloric acid aqueous solution was electrolyzed.
Was obtained.

In the first embodiment, the electrolytic sterilizing water 10
The power required to produce 001 was 38 Wh,
The power effect was 0.29 g / Wh.

Example 2 The same apparatus as in Example 1 (see FIG. 1) was used. However, one intermediate electrode was further added to the bipolar electrode in the non-diaphragm electrolytic cell 5, and the bipolar electrode was changed to a bipolar electrode having a total of two intermediate electrodes. Further, two bipolar electrodes were connected in parallel.

Electrolytic sterilization water was produced by the following procedure using the modified apparatus. That is, hydrochloric acid C having a concentration of 21% is stored in the hydrochloric acid container 6, and 1200 l of water is supplied from the water source 1 to the main pipe 2.
/ H at a flow rate of / h. 600 ml / h for branch pipe 2a
The water is branched and flowed at a flow rate of
The mixture was injected into the branch pipe 2 a at a flow rate of ml / h, and an aqueous hydrochloric acid solution was passed through the non-diaphragm electrolytic cell 5.

In the non-diaphragm electrolytic cell 5, a voltage of 5.
As a result of passing a current at 5 V and a current of 17 A to electrolyze the hydrochloric acid aqueous solution, electrolytic sterilizing water having an effective chlorine concentration of 45 ppm was obtained from the outlet 8.

In Example 2, the electrolysis sterilized water 10
The power required to produce 001 was 92 Wh,
The power effect was 0.49 g / Wh, which was about twice that of Example 1.

Comparative Example Using the same apparatus as in Example 2 (see FIG. 1), the hydrochloric acid in the hydrochloric acid container 6 was diluted with water. Next, sodium chloride was added to prepare a raw material water containing both hydrochloric acid and sodium chloride. Incidentally, the chlorine ion concentration was determined according to Example 2 described above.
The concentration was adjusted to be the same as

As described above, when the electrolysis sterilized water was manufactured under the same conditions as in Example 2 using the apparatus in which the inside of the hydrochloric acid container 6 was changed, the electric power required to manufacture 1000 liters of the electrolyzed sterilized water was 162 Wh. Yes, power effect is 0.26g /
Wh. That is, by adding sodium chloride to the raw water, the electric power effect was greatly deteriorated as compared with Example 2.

The running costs of Example 2 and Comparative Example were estimated respectively, and it was found that Example 2 and Comparative Example showed that chlorine 1
The electric power per g was about 53% in Example 2 compared to the comparative example, and it was found that the running cost of Example 2 was extremely low as compared with the comparative example.

Embodiment 3 FIG. 3 is a schematic view showing another example of an apparatus for performing the method of the present invention. 3, elements common to FIG. 1 are denoted by the same reference numerals as in FIG. 1, and detailed description is omitted.

The apparatus shown in FIG. 3 is almost the same as the apparatus shown in FIG. 1, except that a caustic soda vessel 6a and a metering pump 7 are provided.
a (manufactured by Sataco; SNF-10KP24CU). The 20% caustic soda aqueous solution is stored in the caustic soda container 6a. The electrodes of the electrolytic cell are
This is the same as the second embodiment.

Using the apparatus having the above structure, electrolytic sterilizing water was produced in the following procedure. That is, water was supplied from the water source 1 to the main pipe 2 at a flow rate of 1200 l / h. 33 in the branch pipe 2a
Water was branched off at a flow rate of 0 ml / h, and at the same time, hydrochloric acid C was injected into the branch pipe 2 a at a flow rate of 330 ml / h, and an aqueous hydrochloric acid solution was passed through the diaphragm-free electrolytic cell 5.

In the non-diaphragm electrolytic cell 5, a voltage of 5.5 V and a current of 20 A were applied to the bipolar electrode to electrolyze the hydrochloric acid aqueous solution.

From the caustic soda vessel 6a, the 20% caustic soda aqueous solution was added to the main pipe 2 at a flow rate of 120 ml / h to neutralize the water after electrolysis.

By the above operation, the pH value of pH 6.
3. Electrolytic sterilized water having an effective chlorine concentration of 55 ppm was obtained.

In general, when the effective chlorine concentration of the produced electrolytic sterilizing water is high, the pH of the electrolytic sterilizing water is low. In Example 3, since a step of neutralization with caustic soda was added, it was possible to obtain electrolytic sterilizing water having an appropriate pH despite the high effective chlorine concentration.

[0082]

According to the method for producing electrolytic sterilizing water of the present invention, a bipolar electrolytic cell can be employed without increasing the running cost and without excessively increasing the voltage. Therefore, the following advantages of the bipolar electrolytic cell can be enjoyed, and the economy can be maintained high. (1) Even when a constant voltage power supply is used, an increase in the current value can be suppressed, and the life of the electrodes can be prevented from being shortened. (2) Even when a constant current power supply is used, fluctuations in the voltage value can be avoided and operation can be performed under constant conditions. (3) Even when electrolysis is performed under general conditions that are neither constant voltage nor constant current, the raw water having a high chloride ion concentration can be maintained while maintaining the same current value or voltage value only by adding an intermediate electrode. Can be electrolyzed.

Further, according to the production method of the present invention, the amount of chlorine generated can be increased while maintaining a high power effect, so that the size of the electrolytic cell can be reduced, and investment costs, running costs, and maintenance management can be reduced. It is advantageous in terms of aspect.

Further, by adding a neutralizing agent to the electrolyzed water, it is possible to obtain an appropriate p
Electrolytic sterilizing water having H can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an apparatus for performing the method of the present invention.

FIG. 2 is a schematic diagram showing a test apparatus of the present invention.

FIG. 3 is a schematic diagram showing another example of an apparatus for performing the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water source 2 Main piping 3 Solenoid valve 4 Constant flow valve 5 Non-diaphragm electrolytic cell 6 Hydrochloric acid container 6a Caustic soda container 7 Metering pump 7a Metering pump 8 Outlet

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/76 C02F 1/76 A

Claims (3)

[Claims] Claims: 1. A hydrochloric acid aqueous solution substantially free of sodium chloride is passed through a non-diaphragm electrolytic cell having a bipolar electrode,
An economical method for producing electrolytically sterilized water by electrolyzing a passed hydrochloric acid aqueous solution and collecting the electrolyzed water. 2. The method of claim 1, wherein the electrolyzed water is collected after diluting the electrolyzed water. 3. The method for producing electrolytically sterilized water according to claim 1, wherein the electrolyzed water is collected after adding a neutralizing agent.