JPH0913185A - Production of hydrogen peroxide and water tank - Google Patents

Abstract

PURPOSE: To easily and effectively disinfect the water stored in various tanks. CONSTITUTION: An electrolytic cell 2 with the gas diffusing electrode 5 provided with an oxygen-contg. gas passage 7 on its rear as a cathode and an air-lift pump 3 are inserted into the water, the oxygen-contg. gas passed through the cell is introduced into the air-lift pump, and the water in the electrolytic compartment 6 of the cell is sucked by the resultant suction force. The distance between an anode 4 and the cathode 5 is preferably controlled to 0.2-5mm to treat the water having about the same conductivity as city water. The disinfected water is safe for other organisms such as fishes, the environment is not polluted, the structure of the equipment is made compact, and the running cost is reduced. Further, the installation and maintenance are simplified, liq. chemicals, etc., need not be replenished, and this type of water tank is economically and easily utilized as a large industrial water tank as well as the water tank for goldfishes and tropical fishes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing hydrogen peroxide using an electrolysis cell and a lift tube and a water tank, which can be widely used for disinfecting water in fish breeding water tanks, pools, industrial water tanks and the like. You can

[0002]

2. Description of the Related Art For the disinfection of water in water tanks, various methods such as injection of chemicals such as chlorine, sodium hypochlorite, chlorine dioxide, ultraviolet irradiation and filtration have been used singly or in combination depending on the purpose. Has been done. However, the use of chlorine-based chemicals is not preferable because there is a risk of generation of trihalomethane precursors. The disinfection by ultraviolet irradiation is easily affected by the transparency of the treated water, and the ultraviolet transmittance in water is not so large. Therefore, a large number of ultraviolet lamps are required to effectively disinfect the whole water tank, which imposes a heavy financial burden.

[0003]

Therefore, the present invention has been completed for the purpose of providing a method for easily and effectively disinfecting stored water in various water tanks and a water tank for easy disinfection. In the present invention, the water tank includes various fish breeding water tanks, drinking water water tanks, industrial water tanks, fire prevention water tanks, and the like, as well as pools and fish farms.

[0004]

A description will be given with reference to FIG. The present invention inserts an electrolysis cell 2 having a gas diffusion electrode 5 having a flow path 7 for oxygen-containing gas on the back surface side as a cathode and an air lift tube 3 into water to remove an oxygen-containing gas passing through the electrolysis cell. Electrolyte chamber 6 of electrolysis cell introduced into air lift tube
And a method for producing hydrogen peroxide, which comprises sucking the water. In order to treat the most common tap water or water having an electric conductivity of about industrial water, the distance A between the anode and the cathode is preferably 0.2 to 5 mm.

Further, the present invention is composed of a cathode 5 of a gas diffusion electrode having a flow path 7 for oxygen-containing gas on the back side thereof, and an anode 4 which faces the cathode by sandwiching the electrolysis chamber 6. An electrolysis cell 2 and an air lift pipe 3 that uses the oxygen-containing gas that has passed through the electrolysis cell as a gas source are provided. Provided is an aquarium tank 1 characterized by being sucked.

[0006]

Actions and Embodiments The present invention will be specifically described with reference to FIG. FIG. 1 is a schematic view showing an embodiment example of the present invention. In order to produce hydrogen peroxide using the present invention, for example, to disinfect water in a water tank, a cathode 5 of a gas diffusion electrode that faces the anode of the electrolytic chamber 6 with the anode 4 and the electrolytic chamber 6 sandwiched in the water tank 1 is used. The electrolysis cell 2 and the air lift tube 3 are attached. Electrolysis chamber 6 and air lift tube 3
A water guide pipe 8 is provided, for example, between the lower side surface and the lower side face so that the water in the electrolysis chamber 6 is effectively sucked by the air lift pipe 3. As the electrode material, the anode is one in which titanium is coated with iridium or platinum as a material that does not generate cations, and the cathode is one in which carbon black is mainly mixed and powder of polytetrafluoroethylene (PTFE) is kneaded and molded. Good. A flow path 7 for oxygen-containing gas is provided on the back surface side of the cathode 5. Taking the case where air is used as the oxygen-containing gas, for example, the air can be fed through the air feed pipe 10 by the air pump 9 or the like. A gas conduit 11, for example, is provided between the outlet side of the flow path 7 and the bottom of the air lift pipe 3 to facilitate the introduction of gas into the air lift pipe 3.

The air sent into the flow path 7 by the air pump 9 is further guided to the air lift pipe 3 and flows upward from the bottom portion to form a multiphase flow with water, thereby exhibiting an air lift action. Water in the electrolysis chamber 6 is sucked by this air lift action, and water in the water tank 1 is sucked in the electrolysis chamber 6. During this period, electrolytic reduction is performed in the electrolytic chamber 6 to reduce oxygen and produce hydrogen peroxide. Water and gas are discharged from the upper part of the air lift pipe, and the water is returned to the water tank together with the produced hydrogen peroxide. The water in the water tank is disinfected with hydrogen peroxide and can be kept in a clean state. Electricity is supplied to the electrolysis cell from a power supply 12 via a lead wire 13. From the viewpoint of ease of electrolysis, the treated water preferably contains a large amount of highly conductive electrolyte, but water having a conductivity of about 100 to 300 μS / cm, such as commonly used tap water. However, the distance between the anode and the cathode is 0.2 ~
By setting the thickness to about 5 mm, the present invention can be easily implemented at a low voltage. Since the electrolytic cell is immersed in water, it is necessary to pay sufficient attention to the insulating properties of the electrolytic cell and the like.

Generally, economical air is used as the oxygen-containing gas used in the present invention, but when the production efficiency of hydrogen peroxide is desired to be increased in a large-scale water tank, the oxygen concentration is higher than that of air. A gas, for example, an oxygen-containing gas having an oxygen concentration of 90 to 95% obtained by treating air with a PSA oxygen generator,
Oxygen in a cylinder can be used. The amount of water sucked into the electrolytic cell can be adjusted by adjusting the flow rate of the oxygen-containing gas to the electrolytic chamber or the air lift pipe. When the amount of water increases, the concentration of hydrogen peroxide in the water discharged from the electrolysis cell decreases, but the amount of hydrogen peroxide produced is almost constant regardless of the increase or decrease in the amount of water.

[0009]

EXAMPLE In order to confirm the effect of the present invention, a hydrogen peroxide generation experiment with a different distance between electrodes and a pumping experiment of an air lift pipe were carried out. The results are shown. Example 1 An electrolytic cell having an electrode area of 0.18 dm ² was prepared by using an electrode having an anode coated with iridium oxide based on titanium, and a cathode having a gas diffusion electrode formed by mixing carbon black and polytetrafluoroethylene powder. The generation of hydrogen peroxide was confirmed by performing electrolytic reduction using tap water as an electrolytic solution and air as an oxygen-containing gas. The electrolysis conditions are an air amount of 500 ml / min and a tap water amount of 100 to 33.
0 ml / min (16.3 ° C), voltage between electrodes 5.04V
Met. The amount of water was measured by receiving hydrogen peroxide-forming water at the outlet of the electrolysis cell in a measuring cylinder, and the hydrogen peroxide concentration was measured by the potassium permanganate method. Table 1 shows the measurement results.

[0010]

[Table 1] Distance between electrodes Water amount Current value Hydrogen peroxide concentration mm ml / min A ppm 0.5 330 330 0.24 7 1 330 330 0.15 4 5 330 0.04 1 0.5 100 100 0.24 23 Example 2 The anode 2 was placed in a water tank 21 using the apparatus outlined in FIG.
4 and a cathode 25 which is a gas diffusion electrode, an electrolysis cell 22 having an electrolysis chamber 26 and an air lift pipe 23 are attached, and the amount of pumped water is changed by changing the amount of air sent into the electrolysis cell. Confirmed the performance of. The effective length of the air lift pipe is 160 mm, the water conduit 28, the gas inlet pipe 3
A silicon tube having an inner diameter of 5 mm and an outer diameter of 8 mm was used for 0 and the gas conduit 31. The electrode area of the electrolysis cell is 18 cm ² ,
The distance between the electrodes was 0.5 mm. The amount of pumped water from the air lift pipe was measured by receiving the water overflowing from the pumped water discharge pipe 32 in the measuring flask 33.

[0011]

[Table 2] Air volume (ml / min) Pumped water volume (ml / min) 660 70 800 90 90 1,300 120 2,500 140

[0012]

The method for producing hydrogen peroxide of the present invention can be easily used for disinfecting water in a water tank or the like. There is no concern about producing trihalomethane precursors like chlorine-based bactericides, and since no third substance such as sodium hydroxide is used, disinfected water is safe for other organisms such as fish and causes no environmental pollution. There is no concern. Even in tap water or industrial water, which is generally used and has low conductivity, hydrogen peroxide can be generated and disinfected without requiring a high voltage by reducing the distance between the electrodes. The water in the electrolysis cell is sucked and supplied by an air lift that uses the exhaust of the oxygen-containing gas used for the cathode, so there is no cost, there is no need to install a water pump, and the overall equipment configuration is compact and operating costs are high. There is an effect that can be saved. Since air is usually used as the oxygen-containing gas, it is possible to easily adjust the amount of supplied air by increasing or decreasing the amount of supplied air. When it is necessary to increase the amount of hydrogen peroxide generated, such as when disinfecting water in a large water tank, increasing the oxygen concentration in the oxygen-containing gas can cope with this without increasing the size of the equipment.
It is easy to install and maintain, does not require replenishment of chemicals, etc., and can be economically used easily from aquariums of goldfish and tropical fish to large industrial aquariums.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an embodiment of the present invention.

FIG. 2 is a schematic diagram of a test apparatus used in Example 2.

[Explanation of symbols]

1: Water tank 2: Electrolysis cell 3: Air lift pipe 4: Anode 5: Cathode 6: Electrolysis chamber 7: Oxygen-containing gas passage 8: Water conduit 9: Air pump 10: Gas inlet pipe
11: Gas conduit 12: Power supply 13: Lead wire 21: Water tank 22: Electrolysis cell 23: Air lift pipe 24: Anode 25: Cathode 26: Electrolysis chamber 27: Oxygen-containing gas flow path 28: Water pipe 29: Air pump 30: Gas Inlet pipe 31: Gas conduit 32: Pumped water discharge pipe 33: Volumetric flask

Claims (3)

[Claims] 1. An oxygen-containing gas that passes through an electrolysis cell by inserting an electrolysis cell 2 having a gas diffusion electrode 5 provided on the back surface side of the oxygen-containing gas 5 as a cathode and an air lift tube 3 into the water, Is introduced into an air lift tube to suck water in the electrolysis chamber 6 of the electrolysis cell. 2. The method for producing hydrogen peroxide according to claim 1, wherein the distance between the anode and the cathode is 0.2 to 5 mm. 3. An electrolysis cell 2 comprising a cathode 5 of a gas diffusion electrode having a flow path 7 for oxygen-containing gas provided on the back surface side thereof, and an anode 4 facing the cathode with the electrolysis chamber 6 interposed therebetween. In addition, an air lift pipe 3 is provided, which uses the oxygen-containing gas that has passed through the electrolysis cell as a gas source, guides the oxygen-containing gas blown to the back surface of the cathode to the bottom of the air lift pipe, and sucks water in the electrolysis chamber 6 by the air lift pipe. An aquarium characterized by that.