JPH1110160A - Method for treating water by electrolytic oxidation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently treat wastewater by electrolytic oxidation decomposition by employing solid active carbon for electrodes for the electrolysis. SOLUTION: In water treatment method by electrolytic oxidation decomposition, the electrodes for electrolysis are solid active carbon electrodes 1 made of active carbon/carbon composite material and the active carbon is an active carbon powder or active carbon fiber and the carbon composite material is a composite material of carbonized phenolic resin. The method is for treating wastewater such as industrial wastewater by oxidation decomposition in an electrolytic bath in which such a solid active carbon electrode 1 made of the carbon composite material is used for at least either one of a cathode and an anode. In the same manner, the method may be applied to purified water production method to purify tap water, an electrolytic solution production method to obtain electrolytic solution by electrolyzing water, an electrolytic oxidation water treatment method, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water treatment method such as a waste liquid treatment method utilizing electrolytic oxidative decomposition, a purified water producing method, and an electrolytic water producing method.

[0002]

2. Description of the Related Art In order to prevent the destruction of the natural environment by industrial waste liquid, there is a demand for an effective, immediate and economical method for removing organic substances and the like contained in the waste liquid. Conventional methods include, for example, a biodegradation method and a chemical decomposition method using sodium hypochlorite. Further, JP-A-2-131184 discloses a method of adsorbing and removing organic substances on activated carbon, and JP-A-7-265860, JP-A-8-281271 and JP-A-8-296081 disclose a method.
An electrolysis removal method is shown.

[0003] In addition, a large amount of disinfectant mainly containing chlorine is supplied to tap water. As a result, tap water contains trihalomethanes, which have been pointed out as carcinogenic, and their removal is required. In such a water purification device, generally, a cartridge or the like in which an activated carbon layer and a hollow fiber membrane layer are integrated is widely used.

As a method for washing and sterilizing various food and medical / hygiene equipment, an aqueous sodium hypochlorite solution is generally used as sterilizing water. Recently, a method using electrolytic sterilization as described in JP-A-8-308910 has also been used. In general, platinum or the like is used as an electrode for electrolytic sterilization.

[0005]

The above-mentioned conventional water treatment methods have various problems and none of them is satisfactory.

That is, the biodegradation method has a problem that the decomposition time is very long. Further, in the method of chemical decomposition using sodium hypochlorite, there is a problem that the running cost is increased because sodium hypochlorite cannot be recycled. Further, Japanese Patent Application Laid-Open No.
In the method of adsorbing on activated carbon as described in Japanese Patent No. 1184, there is a problem that the cost is extremely high because the activated carbon is not efficiently reused.

In the case of the electrolysis method described in the above-mentioned JP-A-8-281271 and JP-A-8-296081, platinum, ruthenium dioxide, lead dioxide, tin dioxide, stainless steel, graphite and the like are used for electrodes. However, there is a problem that metal materials other than graphite are gradually corroded and flow out as toxic materials.

[0008] In the case of graphite, although there is no corrosion, there is a problem that it is severely worn and cannot be processed at a high current density. In addition, Japanese Patent Application Laid-Open No. 7-265862 discloses a method in which activated carbon powder is filled in a net to form an auxiliary electrode of an anode in order to increase the contact area of the electrode.

However, an electrode having a structure in which activated carbon powder is covered with a net or the like has problems that the contact resistance is extremely high and fine powder scatters from the net.

[0010] In the case of a water purification apparatus using a cartridge in which the activated carbon layer and the hollow fiber membrane layer have an integral structure, if the water purification efficiency is reduced, the cartridge must be replaced, which wastes resources. There is a problem. Further, since the cartridge is used in a gradually contaminated state, harmful fungi proliferate, which is a serious hygiene problem.

The aqueous sodium hypochlorite solution generally used for sterilization treatment of foods and medical treatments cannot be regenerated as described above, so that not only the running cost is increased, but also chemically unstable. There is a problem that long-term storage cannot be performed and proper concentration control is difficult.

Further, in the conventional electrolytic sterilization method, a metal material such as platinum or ruthenium dioxide, graphite, or the like is generally used, but there is a problem of corrosion and abrasion as in the waste liquid treatment.

[0013] It is an object of the present invention to provide various water treatment methods such as waste liquid treatment, purified water generation, and electrolyzed water generation, which are free from the above-mentioned problems and have a catalytic action, adsorption ability, and the like of solid activated carbon.
Utilizing characteristics such as a solid electrode material with high current density and low resistance, it is possible to perform electrolytic oxidation effectively in a short time,
An object of the present invention is to provide an excellent electrolytic oxidation water treatment method.

[0014]

The above objects and objects are solved and achieved by the present invention described below.

That is, according to the present invention, in the method for water treatment by electrolytic oxidation, the electrode for electrolysis is a solid activated carbon electrode made of activated carbon / carbon composite material, and the activated carbon is made of activated carbon powder or activated carbon fiber; Electrolytic oxidizing water characterized by subjecting water to be treated to electrolytic oxidative decomposition using an electrolysis tank provided with a solid activated carbon electrode, which is a composite material of a phenolic carbide, at least one of a cathode and an anode. It discloses a processing method.

Further, the present invention is characterized in that the water to be treated is an industrial waste liquid and is a waste liquid treatment method for subjecting the industrial waste liquid to electrolytic oxidative decomposition treatment. It is a waste liquid containing metal ions such as a plating solution.

The present invention is also a method for producing purified water, wherein the water to be treated is tap water, and the tap water is subjected to electrolytic oxidative decomposition purification treatment, and after purification, deposits on solid activated carbon are treated by electrolysis. It is characterized by comprising a mechanism.

Further, the present invention is characterized in that the water to be treated is water, and the method is a method for producing electrolyzed water by electrolyzing the water to obtain electrolyzed water.

The solid activated carbon in the present invention is a solid activated carbon obtained by binding ordinary activated carbon powder with a phenolic carbide. Therefore, while maintaining the original excellent properties of activated carbon, such as a very large surface area, having a catalytic action, and excellent adsorption capacity, it is also an excellent solid that has low resistance, high density, and easy handling. Electrode is realized.

As a result, by using the above-mentioned solid activated carbon for the electrolytic electrode, an efficient and inexpensive oxidizing electrolyzer can be constructed, and various kinds of excellent electrolytic oxidizing processes such as waste liquid treatment, purified water generation and electrolyzed water generation can be achieved. It has become possible to provide a water treatment method.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to embodiments based on the drawings, but the present invention is not limited thereto.

Example 1 As Example 1, a powder obtained by mixing 70% by weight of activated carbon powder and 30% by weight of a phenol resin was molded at a pressing pressure of 0.5 tonf / cm 2. The obtained activated carbon-containing phenolic resin molded body in an electric furnace,
Heat treatment was performed at 900 ° C. for 2 hours in an N 2 atmosphere. As a result of the heat treatment, the phenol resin was carbonized, and as a result, solid activated carbon, which was an activated carbon / carbon composite, was obtained.

The obtained solid activated carbon has a specific surface area of 800 m.
2 / g, density 0.9 g / cm 3, size 15 × 10 × 0.3
cm. The solid activated carbon electrode 1 thus obtained was
On the other hand, it was installed in the electrolytic cell 2 and the electrolytic cell 2 was filled with waste liquid.
The waste liquid has a COD value of 500 mg / l and a neutral surfactant dissolved therein. The waste liquid further contains 0.5 g / l
Of sodium chloride was added.

A DC power supply 3 is provided between the solid activated carbon electrodes 1 to
A constant current of 100 A was applied at 10 V for 10 minutes. The COD value of the waste liquid after performing such electrolytic oxidation is 18 mg / l.
Down to

[Embodiment 2] As Embodiment 2, the same configuration as that of Embodiment 1 is used, containing 5 g / l of copper ion and 0.5.
The same electrolytic oxidation as in Example 1 was performed on the waste liquid to which g / l of sodium chloride had been added. The copper ion concentration of the waste liquid after the electrolytic oxidation was reduced to 2 mg / l.

Example 3 As Example 3, a pair of solid activated carbon electrodes 1 manufactured by the same method as in Example 1 was used.
It was immersed in tap water having a trichloromethane concentration of 50 ppb. The trichloromethane concentration after sufficiently stirring the tap water is 1 pp
b. This batch process was performed once a day for 30 days. At that time, when a constant current of 100 A was flowed between the solid activated carbon electrodes 1 at 10 V, compared with a case where no current was flowed,
The number of bacteria could be reduced to 5%.

Example 4 As Example 4, a solid activated carbon was produced in the same manner as in Example 1. The electrolytic chamber 4 has a diaphragm 5 and is divided into two electrolytic chambers. The solid activated carbon electrode 1 was installed in each electrolytic chamber, and connected to the anode terminal and the cathode terminal of the DC power supply 3, respectively. The electrolytic chamber 4 was filled with tap water in which sodium chloride was dissolved at a rate of 0.5 g / l.

100 A at 10 V between solid activated carbon electrodes 1
For 10 minutes.

Thereafter, the glass plate 6 coated with proteinaceous soil was immersed in the electrolytic chamber 4 provided with the solid activated carbon electrode 1 connected to the anode terminal. As a result, the protein was decomposed after about 5 minutes. .

Comparative Example 1 Next, as Comparative Example 1, the same waste liquid treatment as in Example 1 was performed using a graphite plate having a size of 15 × 10 × 0.3 cm as an electrode. When 100 A was passed at a current density of 10 V similar to that in Example 1, the anode was instantaneously worn. Therefore, a constant current of 0.1 A, which does not cause abrasion of the graphite plate, was applied for 10 minutes. As a result, the COD value of the waste liquid decreased only to 250 mg / l.

[0032]

As described above, according to the electrolytic oxidizing water treatment method of the present invention, the current density can be greatly increased by performing electrolytic oxidation using an electrolytic cell having an electrolytic electrode made of solid activated carbon. The effect is that the electrolytic oxidation can be performed effectively in a short time.

Further, the catalytic action of activated carbon, high adsorption capacity,
Taking advantage of the excellent characteristics as a low-resistance electrode material, it can be applied to all devices related to water treatment by electrolytic oxidation such as waste liquid treatment, purified water generation, and electrolytic water generation, and has a remarkable effect.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a configuration of an apparatus for performing electrolytic oxidized water treatment according to one embodiment of the present invention.

FIG. 2 is a schematic view showing a configuration of an apparatus for performing electrolytic oxidized water treatment according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solid activated carbon electrode 2 Electrolyzer 3 DC power supply 4 Electrolysis chamber 5 Partition wall 6 Glass plate which applied protein

Claims (5)

[Claims] 1. A method for treating water by electrolytic oxidation, wherein the electrode for electrolysis is a solid activated carbon electrode made of an activated carbon / carbon composite material, and the activated carbon is made of activated carbon powder or activated carbon fiber, and the carbon composite material is a phenol resin. A process for electrolytically oxidizing and decomposing water to be treated using an electrolysis tank provided with at least one of a cathode and an anode, which is a solid activated carbon electrode which is a composite material of carbides. 2. The electrolytic oxidized water treatment method according to claim 1, wherein the method for electrolytically decomposing the water to be treated is a waste liquid treatment method for electrolytically oxidizing and decomposing industrial waste liquid. 3. The electrolytic oxidized water treatment method according to claim 2, wherein the industrial waste liquid is a waste liquid containing metal ions such as a plating solution. 4. The method for electrolytically oxidizing and decomposing water to be treated is a purified water producing method for performing electrolytic oxidatively decomposing and purifying treatment of tap water, and a mechanism for treating the deposits on the solid activated carbon after purification by electrolysis. The method for treating electrolytic oxidized water according to claim 1, comprising: 5. The electrolytic oxidized water treatment method according to claim 1, wherein the method of electrolytically decomposing the water to be treated is an electrolytic water generation method of electrolyzing water to obtain electrolytic water.