JP3398173B2 - Electrolysis method of saline solution - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for electrolyzing saline.

[0002]

2. Description of the Related Art As an example of a method for electrolyzing a saline solution, as disclosed in JP-B-4-42077 and JP-A-4-330987, an electrode is provided in each compartment partitioned by a diaphragm. To form an anode chamber and a cathode chamber,
There is a method of electrolyzing saline solution in which acidic water is produced in the anode chamber and alkaline water is produced in the cathode chamber by electrolyzing the saline solution in both chambers. Of these produced water, acidic water has a bactericidal action, and alkaline water has a color change-preventing action for fish and shellfish and a drip-preventing action, since it has a color change-preventing action for vegetables. Each of these produced waters is used, for example, as a fresh food treatment liquid.

However, in the above-described method of electrolyzing saline solution, when electrolysis is continuously performed, salts such as calcium or scales such as hydroxides are deposited on the electrode, and the current value is gradually decreased and the electrode is gradually reduced. There is a problem that it deteriorates. Further, there is a problem that such scale is also deposited on the diaphragm and the diaphragm is deteriorated.

As a means for coping with this, in the electrolysis method shown in the latter publication mentioned above, a direct current voltage is alternately applied to the both electrodes respectively arranged in each compartment every predetermined time, and the direct voltage is alternately applied. A method of preventing scale deposition on each electrode and diaphragm by electrolyzing a saline solution in each compartment is adopted.

[0005]

By the way, in the latter electrolysis method described above, the deposition of scale on each electrode and the diaphragm can be prevented, but the scale remains on the anode chamber side when the applied voltage is switched between the forward and reverse directions. Hydrogen ions in acidic water are absorbed by the electrode switched to the cathode side.
Therefore, each electrode is reduced and deteriorates or is damaged. . Therefore, an object of the present invention is to prevent such deterioration and damage of electrodes in the method of electrolyzing saline solution.

[0006]

According to the present invention, a direct current voltage is alternately applied to both electrodes respectively arranged in a compartment partitioned by a diaphragm every predetermined time, and a saline solution is applied to each compartment. In the method of electrolyzing salt water, which is electrolyzed to generate acidic water in the anode chamber and alkaline water in the cathode chamber of each of the compartments, an anode is used when the direct voltage is switched between the two electrodes. It is characterized in that a positive voltage lower than the voltage at the time of electrolysis is applied to the electrode on the chamber side for a short time.

In the electrolysis method, at least one of the electrodes is an electrode having a platinum iridium coating on the surface of a titanium base material, and the low positive voltage is 2 to
It is preferably 5V.

[0008]

In the electrolysis method of the present invention, hydrogen ions are generated and exist in the anode chamber during the electrolysis in which the set predetermined voltage is applied. If a low positive voltage is applied to the anode side electrode, hydrogen ions will not repel the same electrode and enter the same electrode. While this low voltage is being applied, electrolysis is stopped, and hydrogen ions remaining in the anode chamber flow out from the anode chamber together with the supplied saline solution. After that, when the applied voltage to each electrode is switched, the anode chamber and the cathode chamber are changed to each other, but the cathode chamber after switching (the anode chamber before switching) has a higher concentration than raw water (water before electrolysis). Since hydrogen ions no longer remain, it is possible to prevent the deterioration and damage of the electrodes. For example, in tap water, the pH is usually 5.6 to 8.0, the hydrogen ion concentration is 10-5.610-8 mol / l, and the hydrogen ion concentration in the cathode chamber after switching the applied voltage in the present invention is 1/1000. To 1 / 100,000.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows an electrolysis apparatus for carrying out the electrolysis method of the present invention. The electrolyzer (hereinafter sometimes referred to as an electrolyzer) is used as an apparatus for producing a processed liquid for fresh food, and the electrolyzer 10
And a supply line 20 for the electrolytic solution and an outflow line 30 for the electrolytic solution
And an electric system path 40.

The electrolytic cell 10 is a well-known one, and a diaphragm 12 is provided on the cell body 11 to divide the cell body 11 into two compartments R1 and R2. Electrodes 13 and 14 are arranged in the compartments R1 and R2, respectively. The supply pipeline 20 is composed of a main pipeline 21 connected to a supply source of dilute salt water, and first and second sub pipelines 22 and 23 branched from the pipeline 21, and the first sub pipeline 22 is a first pipeline. Second sub-line 2 connected to room R1
3 is connected to the second compartment R2.

The outflow conduit 30 is composed of first and second main conduits 31 and 3.
2, the first and second solenoid valves 33 and 34, the first and second auxiliary pipelines 35a and 35b, and the third and fourth auxiliary pipelines 36a and 36b.
Consists of. The first main conduit 31 is the first compartment R of the electrolytic cell 10.
1 and the inflow port of the first solenoid valve 33, and the second
The main conduit 32 is connected to the second compartment R2 of the electrolytic cell 10 and the second solenoid valve 3
4 inflow ports. First and second auxiliary pipeline 3
5a and 35b are connected to respective outflow ports of the first solenoid valve 33, and the third and fourth sub-pipes 36a and 36b are connected to respective outflow ports of the second solenoid valve 34, and
The fourth sub-pipes 35b and 36b are the first and third sub-pipes 35a,
It is connected to 36a.

The electric system path 40 applies a voltage to each of the electrodes 13 and 14, and is provided with a pair of DC power sources 41 and a pair of changeover switches 42 and 43. Both switches 42, 4
3 operates in conjunction with each other, so that the electrodes 1
The forward and reverse of the applied voltage to 3 and 14 are switched. In addition,
The switching operation of the electrodes 13 and 14 is performed by the control device 44 in conjunction with the switching operation of the electromagnetic valves 33 and 34.
At the same time, the controller 44 also controls the applied voltage to the electrodes 13 and 14.

In the electrolyzer having such a construction, first, the first electrode 13 is used as an anode and the second electrode 14 is used as a cathode, and a DC voltage of 40 to 50 V is applied to the first compartment R1 as an anode compartment and a first compartment R1 as an anode compartment. The second chamber R2 is used as a cathode chamber, and both chambers R1 and R2 have 0.05 to 0.15 wt.
% Diluted saline solution is supplied. As a result, each room R1,
In R2, the saline solution reacts as described below, the acidic water containing hypochlorous acid flows out from the first auxiliary pipeline 35a connected to the first main pipeline 31, and is connected to the second main pipeline 32. Alkaline water containing sodium hydroxide flows out from the third auxiliary pipeline 36a.

[0014]

[Chemical 1]

After the electrolysis is continued for 20 to 30 minutes, the voltage applied to both electrodes 13 and 14 is lowered to 2 to 5 V and applied for 30 seconds to 3 minutes, and then the forward and reverse of the voltage is switched to 40 to 5 volts.
A DC voltage of 0 V is applied to change the first compartment R1 to the cathode compartment and the second compartment R2 to the anode compartment to continue electrolysis. Interlocking with this switching, both solenoid valves 33 and 34 are also switched and actuated, and the second main pipeline 3 is connected via the fourth sub pipeline 36b.
Acid water flows out from the first sub-pipe 35a connected to the second sub-pipe 35b, and is connected to the first main pipe 31 through the second sub-pipe 35b.
Alkaline water flows out from the sub pipeline 36a.

In the electrolysis method according to the present invention, a predetermined DC voltage set to both electrodes 13 and 14 is applied to electrolyze for a predetermined time, and then the applied voltage is reduced to a predetermined low voltage for a short time, After that, the DC voltage is switched between forward and reverse, and a predetermined set voltage is applied to both electrodes 13 and 14 to perform electrolysis for a predetermined time, which is defined as one unit, and this is repeated one or more times. is there. Therefore, the time chart of the applied voltage at the first electrode 13 is as shown in FIG. 2, and the time chart of the applied voltage at the second electrode 14 has the opposite relationship. Further, the time chart shown in FIG. 3 is a modification of the time chart shown in FIG. 2, and it is possible to apply a low voltage to two stages of forward and reverse when switching between forward and reverse voltages.

In this electrolysis method, both electrodes 13,
Since the direct voltage of the DC voltage applied to 14 is switched at regular intervals, no scale deposition is observed on both electrodes 13 and 14 and diaphragm 12.

Further, when H ⁺ remaining in the anode chamber is converted to H when the voltage is switched between forward and reverse, H functions as a strong reducing agent, so that the electrode film is reduced and the film is reduced. It dissolves and is consumed, and also penetrates the substrate through the coating, degrading the substrate. For example, in an electrode having a platinum iridium coating with titanium as a base material, the following reactions occur.

[0019]

[Chemical 2]

Such a phenomenon is caused by switching forward and reverse of the applied voltage all at once, but by applying a positive low voltage to the anode side electrode when switching the applied voltage as in the present invention, H ⁺ becomes And H ⁺ are prevented from entering the electrode. For this reason, H ⁺ remaining in the anode chamber flows out of the electrolytic cell 10 together with the supplied saline solution to become neutral saline solution in the anode chamber, and the frequency of occurrence of the above reaction due to subsequent switching of the applied voltage is 1 It becomes 1 / 10,000 to 1 / 100,000, which prevents deterioration and damage of the electrode.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an electrolysis apparatus suitable for carrying out an electrolysis method of the present invention.

FIG. 2 is an example of a time chart of a voltage applied to an anode electrode.

FIG. 3 is another example of the same time chart.

[Explanation of symbols]

10 ... Electrolyte tank, 11 ... Tank body, 12 ... Diaphragm, 13, 14
... Electrodes, 20 ... Supply pipelines, 30 ... Outflow pipelines, 33, 34
... Solenoid valve, 40 ... Electric system path, 41 ... DC power source, 42, 4
3 ... Changeover switch.

Claims (2)

(57) [Claims] 1. A direct current voltage is applied alternately to both electrodes arranged in each compartment partitioned by a diaphragm every predetermined time to electrolyze a saline solution in each compartment, and the saline solution is electrolyzed in each compartment. Among them, in the method of electrolyzing saline solution in which acidic water is generated in the anode chamber and alkaline water is generated in the cathode chamber, in the electrolysis of the electrode on the anode chamber side when switching the direct voltage to the both electrodes between forward and reverse. A method for electrolyzing a saline solution, which comprises applying a positive voltage lower than the voltage for a short time. 2. The electrolysis method according to claim 1, wherein
At least one of the two electrodes is an electrode having a platinum iridium coating on the surface of a titanium base material, and the low positive voltage is 2 to 5 V.