JP2005087982A - Method for producing chlorine dioxide-containing solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for safely and easily utilizing chlorine dioxide having excellent property as a disinfectant at a low cost. <P>SOLUTION: This method is established by ascertaining generation of chloric acid when chlorine ion is electrolyzed above prescribed voltage in a nondiaphragm electrolytic cell and ascertaining generation of chlorine dioxide by the following reaction of chloric acid with hydrochloric acid which is supplied as a raw liquid or is secondarily produced by reaction of chlorine generated by electrolysis and water. 2HClO<SB>3</SB>+ HCl → 2ClO<SB>2</SB>+ HClO + H<SB>2</SB>O. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a method for producing a chlorine dioxide-containing solution.

Chlorine dioxide has a strong bactericidal effect, its bactericidal effect is not affected by pH, it is hard to deactivate by organic matter, and it has excellent properties such as not producing toxic trihalomethane even when contacted with organic matter. Yes. For this reason, it is regarded as a promising alternative to chlorine, which has been widely used, and has already been widely used in Europe and the United States.

There are many known generation methods, and typical ones are shown. Patent Document 1 uses a reaction of chlorous acid, hypochlorous acid, and mineral acid, Patent Document 2 relates to a method of reducing chlorate ions with hydrogen peroxide, and Patent Document 3 mineralizes chlorate ions. A method of reducing with an acid, Patent Document 4 is a method of electrolyzing sodium chlorite in a diaphragm type electrolytic cell, and Patent Document 5 is a method of utilizing a reaction between chlorite ions and an acid. In addition to these, the following production reaction is known.
2NaClO ₂ + Cl ₂ → ClO ₂ + 2NaCl
2NaClO ₃ + H ₂ SO ₄ → 2ClO ₂ + 2NaHSO ₄

However, these conventional methods use special chemical substances as raw materials, and require complicated reaction control and complicated and large-scale equipment. For this reason, there are cases where the storage of raw materials and production reactions are accompanied by dangers, and the apparatus is often large and expensive. Therefore, it has been difficult to safely and easily benefit from the excellent properties of chlorine dioxide over a wide area.
JP 2000-185908 A JP-A-10-259003 JP-A-10-194707 JP-A-9-279476 JP-A-9-268002

The inventor has sought to provide a method that can use chlorine dioxide safely and easily at low cost, which has excellent properties as a disinfectant.

The present inventor conducted an electrolysis of chlorine ions in a diaphragm electrolyzer in the course of earnest research to provide a safe and convenient method for using chlorine dioxide with excellent properties as a disinfectant. He noticed that chlorine dioxide is produced when electrolysis is performed at a predetermined voltage or higher. As a result of detailed investigation of the mechanism of formation, it was confirmed that chloric acid was generated by electrolyzing chlorine ions under suitable conditions, and the chloric acid and hydrochloric acid supplied as a stock solution or chlorine produced by electrolysis It was confirmed that chlorine dioxide was produced by the next reaction with hydrochloric acid produced secondarily by the reaction with water, and the validity of this method was confirmed.
2HClO ₃ + HCl → 2ClO ₂ + HClO + H ₂ O
Furthermore, as a result of repeated research to generate chlorine dioxide efficiently, the voltage applied between the anode and cathode per electrode pair is preferably 4 V or more, more preferably 8 V or more and less than 50 V in the diaphragm membrane electrolytic cell. It was also confirmed that it is more desirably 10V or more and less than 50V. Furthermore, the chlorine dioxide generation efficiency and the electrolysis operation are also closely related to the concentration of chlorine ions to be used. The desirable concentration is 2.5 mol concentration or less and 0.005 mol concentration or more, more desirably 1 mol concentration. It was also confirmed that the concentration was 0.005 molar concentration or higher, more desirably 1 molar concentration or lower and 0.03 molar concentration or higher. Furthermore, the chlorine ion solution should be a hydrochloric acid solution, a salt solution, or a mixed solution of hydrochloric acid and sodium salt to prevent the scale from adhering to the electrode surface during electrolysis. It was also confirmed that it is convenient because it does not contain a compound. Further, the diaphragm electrolyzer used in the present technology is configured such that the electrolytic stock solution enters from the bottom of the tank and flows upward, so that the anode is on the bottom and the cathode is on the top. In the tank where the electrode is placed in the upper and lower positions, or the electrolytic stock solution flows from the front of the tank toward the back, the electrode is moved back and forth so that the anode is at the front and the cathode is at the back. The anode and the cathode are separated by a water-impervious and non-conducting partition, branching into 2 in the middle, 1 is joined to the anode compartment, and the other is joined to the cathode compartment A supply means for the stock solution having the structure as described above, and a discharge means configured so that the electrolytic solution exiting from the anode compartment and the cathode compartment is finally united, etc. The chloric acid produced in step 1 reacts efficiently with hydrochloric acid without immediately reducing and disappearing In the, it was confirmed that the desirable to the generation of chlorine dioxide. Furthermore, the diaphragmless electrolytic cell is a so-called bipolar electrolytic cell in which at least one of the plurality of electrodes arranged inside the electrolytic cell is not directly connected to the power source. It was confirmed that the efficiency was excellent. Based on these confirmations, the present inventor has completed the present invention.

The effect of the present invention is that it is safe to use chlorine dioxide having excellent properties as a bactericidal agent at a low cost. This contributes to the improvement of public health by minimizing the impact on the environment and people by enabling effective sterilization while suppressing the production of trihalomethane.

The best mode for carrying out the present invention is that the concentration is 2.5 molar concentration or less 0.005 molar concentration or more, more desirably 1 molar concentration or less 0.005 molar concentration or more, and even more desirably 1 molar concentration or less 0. The voltage applied between the anode and the cathode per electrode pair in a non-diaphragm electrolytic cell is a chlorine ion solution having a concentration of 0.03 molar or higher, more preferably 8 V or more and less than 50 V, and even more preferably 10 V. The electrolysis is performed at a voltage lower than 50V. Further, the diaphragm membrane electrolytic cell is configured so that the electrolytic stock solution enters from the bottom of the cell and flows upward, and the electrodes are positioned at the upper and lower positions so that the anode is on the lower side and the cathode is on the upper side. Arrangement is also one of the best modes. Furthermore, the diaphragm membrane electrolytic cell is configured so that the electrolytic stock solution flows from the front side of the bath toward the back side, and the electrodes are arranged at the front and rear positions so that the anode is at the front side and the cathode is at the back side. Arrangement is also one of the best modes. Further, the non-membrane electrolytic cell has an anode and a cathode separated by a water-impervious and non-conducting partition wall, branching into 2 in the middle, 1 being joined to the anode compartment and the other being joined to the cathode compartment. It is also one of the best modes that it comprises a supply means for the stock solution having the structure described above, and a discharge means configured so that the electrolysis solution exiting from the anode compartment and the cathode compartment is finally united. One. Furthermore, it is also one of the best modes that the diaphragmless electrolytic cell is a so-called bipolar electrolytic cell in which at least one of the plurality of electrodes arranged inside the electrolytic cell is not directly connected to the power source. One.
Next, in order to further deepen the understanding of the present invention, examples will be shown and described. However, this is not intended to limit the scope of this patent.

One of the generation devices is shown in a block diagram in FIG. The electrolytic cell 4 is configured as follows. Three electrodes, each of which is a 30 mm × 150 mm titanium plate coated with platinum and iridium oxide, are arranged in parallel at intervals of 10 mm, and only two at both ends are connected to the anode or cathode of the power source 5, respectively. The center electrode 12 is not connected to a power source. Further, a rectifying plate 11 is disposed between the electrodes, and a part of the solution flow between the electrodes is separated. A hydrochloric acid solution introducing means 3 is arranged at the lower part of the electrolytic cell, and an electrolytic solution discharging means 6 is arranged at the upper part. The operation of the device is as follows. A fixed amount of hydrochloric acid solution is continuously supplied from the hydrochloric acid solution storage means 1 to the electrolytic cell 4 by the metering pump 2. A direct current is supplied to the electrode of the electrolytic cell 4 from the power source 5. The current supplied at this time is measured by the current measuring means 8 and transmitted to the control means 9 as a signal. The control means 9 compares the current value designated in advance with the actual current value measured by the current measuring means 8, and if the actual current value is insufficient, the supply amount of the hydrochloric acid solution is increased, and if it is excessive, it is decreased. Thus, the metering pump is controlled to control the current value so as to be in a constant state, and thus the electrolytic state is kept constant. With this apparatus, a direct current of 24 V was supplied from the power source to the electrolytic cell so that the hydrochloric acid concentration was 1% and the voltage between the electrodes was 12 V, the electrolysis current value was set to 2 A, and electrolysis was performed. Of chlorine dioxide was continuously obtained at a rate of 450 ml per minute.

Another embodiment will be described with reference to FIG. Since this example has the same configuration as that of Example 1 except for the electrolytic cell and the connection between the electrolytic cell and the power source, only the power source and the electrolytic cell are shown in FIG. The electrodes of the electrolytic cell are arranged in parallel with three electrode plates of 30 mm × 200 mm at intervals of 20 mm, all connected by terminal rods as one configuration, and two configurations at the upper and lower positions, and a length of 50 mm. They are arranged so as to be alternately combined in parallel at intervals of 10 mm, and the lower configuration 15 is connected to the power source anode, and the upper configuration 14 is connected to the power source cathode. With this apparatus, the concentration of hydrochloric acid was 1%, the voltage of 10V was applied between the electrodes, the electrolysis current value was set to 2A, and electrolysis was performed. As a result, the solution containing 50 ppm of chlorine dioxide was 450 ml / min. Obtained continuously.

Still another embodiment will be described with reference to FIG. Since this example has the same configuration as that of Example 1 except for the electrolytic cell and the connection between the electrolytic cell and the power source, only the power source and the electrolytic cell are shown in FIG. 20 is a perspective view from above, and 21 is a side perspective view. The anode 17 and the cathode 16 are disposed parallel to the liquid flow and shifted upstream and downstream. An arrow 18 indicates the direction of liquid flow. With this apparatus, a voltage of 15 V was applied between the electrodes, a 1 molar salt solution was applied, the electrolysis current value was set to 1.5 A, and electrolysis was performed. As a result, a solution containing 20 ppm of chlorine dioxide was 200 ml per minute. Continuously obtained at the rate of.

    One embodiment of the present invention     Power supply unit and electrolytic cell of second embodiment of the present invention     Power supply unit and electrolytic cell of third embodiment of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydrochloric acid solution storage means 2 Metering pump 3 Hydrochloric acid solution delivery means 4 Electrolytic tank 5 DC power supply 6 Electrolyte discharge means 7 Electrolyte storage means 8 Current measurement means 9 Control means 10 Electrode 11 connected to power supply 11 Rectification plate 12 Unconnected electrode 13 Power source 14 Cathode configuration 15 Anode configuration 16 Cathode 17 Anode 18 Solution flow 19 Power source 20 Perspective view from the top of the electrolytic cell 21 Perspective view from the side of the electrolytic cell

Claims (7)

Using a non-diaphragm electrolytic cell, a direct current is applied between the pair of anode and cathode by applying a voltage of 4 V or more, more preferably 8 V or more and less than 50 V, and even more preferably 10 V or more and less than 50 V to electrolyze the chlorine ion solution. Of chlorine dioxide-containing solution The method for producing a chlorine dioxide-containing solution according to claim 1, wherein the concentration of chlorine ions to be used is 2.5 mol concentration or less and 0.005 mol concentration or more, more preferably 1 mol concentration or less and 0.005 mol concentration or more. The method for producing a chlorine dioxide-containing solution according to claim 1, further desirably having a molar concentration of 1 mol or less and 0.03 mol or more. The method for producing a chlorine dioxide-containing solution according to claim 1, wherein the chlorine ion solution according to claim 1 is a hydrochloric acid solution, a salt solution, or a mixed solution of hydrochloric acid and salt. 2. The diaphragm membrane electrolytic cell according to claim 1, wherein the electrolytic solution is entered from the bottom of the cell and flows upward, and the electrodes are arranged so that the anode is at the bottom and the cathode is at the top. The method for producing a chlorine dioxide-containing solution according to claim 1, wherein the chlorine dioxide-containing solution is disposed at a position 2. The diaphragm electrolyzer according to claim 1, wherein the electrode is disposed in the front and back positions so that the electrolytic stock solution flows from the front of the tank toward the back so that the anode is at the front and the cathode is at the back. The method for producing a chlorine dioxide-containing solution according to claim 1, wherein The non-membrane electrolytic cell according to claim 1, wherein the anode and the cathode are separated by an impermeable and non-conducting partition wall, branching into 2 in the middle, 1 being joined to the anode compartment and the other being joined to the cathode compartment And a discharge means configured to finally combine the electrolytic solution exiting the anode compartment and the cathode compartment. Method for producing a chlorine dioxide-containing solution according to Item 1 The non-diaphragm electrolytic cell according to claim 1 is a so-called bipolar electrolytic cell in which at least one of a plurality of electrodes arranged inside the electrolytic cell is not directly connected to a power source. Method for producing a chlorine dioxide-containing solution according to Item 1

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