JPH09323085A - Water electrolytic oxidizing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To purify water containing organic matter, miscellaneous germs and the like by electrolytic oxidation. SOLUTION: When passing water to be treated through an electrode consisting of an oxidation-resistant metal plate to which DC plasma voltage is applied and which has water permeability to perform oxidizing treatment, the back face of the metal electrode (on the outflow side of water and on the opposite side to a cathode) is backed up by a water permeable structural body of carbon with an electrically insulating and water permeable sheet put between them, and DC plasma voltage is applied to the water permeable structural body to perform electrolytic treatment at a current not more than a carbon colloid deposition current value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for electrolytic oxidation of water, and more specifically, bath water containing organic substances and various fungi, water in cages, water in live fish tanks, circulation for water supply in buildings and condominiums. The present invention relates to a method for purifying water, pool water, lake water, etc., such as water used as a circulation and storage tank, by electrolytic oxidation.

[0002]

2. Description of the Related Art The present inventors have invented and have already filed an application for electrolytically oxidizing and purifying circulating water using a water-permeable carbon electrode. According to this method, it was found that excrement of fish in the live fish tank, organic matter in bath water, and other organic matter in water containing organic matter can be oxidized and decomposed. However, there was one problem. This is because when the current density during electrolytic oxidation is increased, the decomposition rate of organic substances is certainly increased, but with the increase of current, the surface of the carbon electrode is also subjected to electrolytic oxidation, and colloidal carbon fine powder is deposited from the surface. That is, the water turns black. Although the deposition of carbon itself is not harmful, there is a problem particularly in applications where circulation and storage tanks are used because water turns black. In order to eliminate the precipitation of fine carbon powder, an oxidation resistant metal other than carbon may be used as an electrode material, but materials resistant to electrolytic oxidation are limited to precious metals such as Pt and Au and Ti. All of these materials are extremely expensive, and it is extremely difficult to form an electrode with these materials alone.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a new method which solves the above-mentioned problems.

[0004]

The above problems are solved by the following means. 1. When water to be treated is passed through an electrode composed of a water-permeable, oxidation-resistant metal plate to which a DC positive voltage is applied, the back surface of the metal electrode (the water outflow side and the opposite side of the cathode)
Is backed up by a carbon water-permeable structure with an electrically insulating water-permeable sheet sandwiched between them, and a direct current positive voltage is applied to the water-permeable structure to carry out electrolytic treatment at a current not higher than the carbon colloid deposition current value. Characteristic method of electrolytic oxidation of water. 2. The method according to 1, wherein the oxidation resistant material is titanium.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION The electrode used in the method of the present invention has a three-layer structure. That is, the inflow side of the water to be treated facing the cathode is made of a water-permeable, oxidation-resistant metal plate, and the back side is backed up by a carbon water-permeable structure with an electrically insulating water-permeable layer sandwiched therebetween. There is. Since the metal plate is thin and can not keep its shape against the flow of water, the carbon water permeable structure serves as a backup for the metal plate to hold the shape, and the electrically insulating water-permeable layer is the metal. It serves to electrically insulate the plate and the water-permeable structure of carbon.

Both the metal plate and the carbon water permeable structure have a higher potential than the cathode, and both the metal plate and the carbon water permeable structure are used as anodes.

The distribution of the anode currents of the metal plate and the carbon permeable structure is such that the metal plate has a high current and the carbon side has a low current. On the carbon side, since a carbon colloid is deposited from the carbon surface when a high current is applied, the current is set to be equal to or lower than the current at which no colloid is deposited. The purpose of electrolytic oxidation on the carbon side is to prevent clogging of water holes of the carbon material and to oxidize and decompose the clogged organic matter. The upper limit of the carbon-side current is approximately 70 to 100 mA when the electrode area (water inflow surface area) is 200 cm ² . If it exceeds this, colloidal carbon will be deposited. The current on the metal plate side is 200
It may be about 500 to 1000 mA in cm ² .

The power supplies applied to the metal plate and the carbon water permeable structure may be the same power supply or may be used separately from one power supply. It is better to share the cathode. When the power source of the metal plate and the carbon water flow structure is shared, the metal plate is closer to the cathode than the carbon electrode and has a low resistance, so a large amount of current flows through the metal plate and blocks the water holes in the metal plate. The stopped organic substances are rapidly decomposed by high current and rapid oxidation in this part. The organic matter that has passed through the metal plate is blocked by the carbon electrode and is oxidized and decomposed here. By adjusting the electrical resistance of the metal plate and the carbon electrode, the roughness of the mesh, and the total current value according to the size and amount of the organic matter contained in the circulating water, the organic matter in the circulating water can be efficiently eliminated by oxidation. .

The carbon water permeable structure is a water permeable structure having a filtering function, such as a fiber, a mesh structure using a wire, a wire, a structure in which fibers are simply wound, a woven fabric, a nonwoven fabric, a porous sintered body, etc. If so, all can be used.

The material of the metal plate is required to be a metal material excellent in oxidation resistance, and a noble metal such as platinum and gold, titanium, and particularly titanium is preferable.

The method of the present invention is to purify circulating bath water, that is, circulating bath water that can be used for 24 hours, food wastewater, culture water tank purification, pool and lake purification, water deodorization, decolorization,
It is effective in breaking down pesticides in water and preventing weeds, moss and algae in paddy fields.

[0011]

【Example】

Example 1 A resin mesh sheet for insulation was wrapped around the surface of a porous carbon sintered body electrode having an outer diameter of 168 mm, an inner diameter of 30 mm and a height of 80 mm, and a wire mesh of titanium fiber having a thickness of 0.2 mm was provided outside the resin sheet. Was fixed by single winding (outer diameter of the wire mesh was 170 mm) and fixed, and this was attached to the electrode box. 1, 2 and 3 are diagrams for explaining this structure. FIG. 1 is a diagram illustrating a structure in which a porous carbon sintered body electrode, a resin sheet, and a titanium wire net are wound. FIG. 2 is a diagram illustrating a structure in which this is attached to an electrode box.
FIG. 3 is a diagram illustrating a situation in which the external power source is connected. 1
Is a porous carbon sintered body electrode, 2 is a resin mesh sheet for insulation, 3 is a titanium wire mesh, 4 is a cathode plate made of stainless steel, and 5 is an electrode box. Reference numeral 6 is an inlet for water to be treated, 7 is an outlet for water, and 8 is a controller for electric current.

<Application to bath water> A stainless steel foil is used as a cathode,
A carbon electrode and a titanium wire mesh were used as an anode, and bath water was circulated. Titanium wire mesh current: 800 mA Carbon electrode current: 90 mA Tested for 20 days. The total number of bathers is 100. Results There were no vermiculous deposits on the carbon and titanium electrodes. It was confirmed that the organic matter was completely decomposed. Escherichia coli in bath water was not detected. There was no scale on the bathtub.

Example 2 (Treatment of pesticide water) The same electrolytic apparatus as in Example 1 was used. A mixture of 15 liters of (dimethyl dicarbethoxyethyl dithiophosphate) in 30 liters of water was circulated all day and night. <Results> Pesticides were not detected. The water, which was cloudy white with pesticides, became clear.

Example 3 (Deodorization of ammonia) The same electrolytic apparatus as in Example 1 was used. Water with ammonia odor was electrolyzed overnight. The smell of ammonia was completely gone.

Example 4 (Removal of water slime) The same electrolytic apparatus as in Example 1 was used. Numerino Tested for hot bath water. The same electrolysis apparatus as in Example 1 was used. Treated for 6 hours. The slime was removed and it became smooth.

Example 5 (Circulating water of cooling tower) The same electrolytic apparatus as in Example 1 was used. Test period 12 months No scale was deposited on the inside of the pipe. There was no red rust on the pipe.

Example 6 (Treatment of water mixed with organic solvent) The same electrolysis apparatus as in Example 1 was used. The water in which 1 ppm of trichlorethylene was detected was treated. Time: 1 day / night Results Trichlorethylene was not detected.

[0018]

INDUSTRIAL APPLICABILITY As described in detail above, the present invention does not cause precipitation of carbon powder even when electrolytically oxidized at a high current, and can be repeatedly used in a state of transparent water. It makes a great contribution. <Application example> 1. Purification of bath water 2. 2. Circulating water of heat exchanger Circulating cooling water 4. Solar system 5. 5. Various water supply and drainage facilities such as water supply and water supply for buildings. 6. Various cooling water scales, measures against red rust Swimming pool Sewage treatment, industrial wastewater treatment 9. 9. Golf course wastewater treatment 10. Water treatment of aquariums and water tanks Pond water purification

[0019]

[Brief description of drawings]

FIG. 1 is a diagram illustrating a structure in which a porous carbon sintered body electrode, a resin sheet, and a titanium wire mesh are wound around each other.

FIG. 2 is a diagram illustrating a structure mounted on an electrode box.

FIG. 3 is a diagram illustrating a situation where an external power source is connected.

[Explanation of symbols]

 1 Porous carbon sintered body electrode, 2 Resin mesh sheet for insulation 3 Titanium wire mesh 4 Cathode plate made of stainless steel 5 Electrode box 6 Water inlet for treatment 7 Water outlet 8 Current control device

Claims (2)

[Claims] 1. When a water to be treated is passed through an electrode made of an oxidation-resistant metal plate having water permeability to which a positive DC voltage is applied to perform an oxidation treatment, the back surface of the metal electrode (on the water outflow side and on the opposite side of the cathode) is treated. Characterized in that an electrically insulating water-permeable sheet is sandwiched between them to back up with a carbon water-permeable structure, and a DC positive voltage is applied to the water-permeable structure to carry out electrolytic treatment at a current below the carbon colloid deposition current value. Method of electrolytic oxidation of water. 2. The method of claim 1, wherein the oxidation resistant material is titanium.