JPH11221570A - Decomposition electrode for organic polluted water, decomposing method of organic polluted water using same and decomposing device of organic polluted water using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrode which can decompose org. substances at low electrolytic voltage that can not be completely ionized. which gives a large throughput for the consumed electric power, which makes neutralization of the treated water unnecessary, and which is excellently convenient without producing of scum or the like by covering the surface of an electrode substrate with a trapping material which traps nitrogen-contg. org. compds. SOLUTION: For example, a commercially available titanium plate in 10 mm×10 mm size and 0.5 mm thickness is degreased with acetone, etched with a hot oxalic acid soln, cleaned with pure water and dried to prepare an electrode base body 1. Then a soln. prepared by dissolving tin chloride and antimony chloride by 100:1 weight ratio in ethanol is applied on the electrode base body 1, dried and baked at 550 deg.C for 10 min. This procedure is repeated to form an electrode coating 2 comprising doped tin oxide having 3μm thickness. Then a trapping material 3 comprising platinum is formed by using a bath of sodium phosphate and ammonium phosphate containing platinic chloride to obtain the decomposition electrode for an org. polluted water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to organic sewage, especially organic sewage containing nitrogen-containing organic compounds, such as wastewater from food processing plants, fishery processing plants, breweries, livestock farms, human waste treatment plants, and wastewater treatment facilities. Decomposition electrode of nitrogen-containing organic sewage suitable for treating organic sewage and purifying bath water of a circulating warm water bath in each household and the like, decomposition method of nitrogen-containing organic sewage using the same, and nitrogen-containing using the same The present invention relates to a device for decomposing organic sewage.

[0002]

2. Description of the Related Art In recent years, environmental protection has been strongly called out by society, and wastewater containing organic matter composed of elements such as nitrogen, phosphorus, and carbon is eutrophic in rivers and lakes, thereby deteriorating the environment. It is necessary to remove organic matter composed of elements such as nitrogen, phosphorus, and carbon and to discharge water.

Conventionally, when such organic matter is in a high concentration,
The treatment is performed by a method of burning by evaporating water or a method of burning by a spray combustion method. Organic components have a low concentration on the order of ppm in general sewage. In such sewage, decomposition by activated sludge or adsorption treatment by activated carbon or the like has been performed.

[0004] However, the incineration method has a problem that it lacks energy saving and is not preferable for global warming. In addition, the biological treatment by the activated sludge method has a slow reaction rate, and requires a large amount of land and time to treat a large amount of wastewater. And temperature and pH to handle microorganisms
In addition, it is necessary to maintain appropriate concentration of the solution at all times, and it is necessary to perform cumbersome management and control to prevent contamination of substances that impair the activity of microorganisms. Even after such troublesome management and control, the total organic carbon TOC (Total Organic)
However, there was a problem that carbon was considerably left and the treatment was incomplete and unsatisfactory.

[0005] Further, in the conventional method of purifying bath water in a circulating warm water bath, aerobic purification bacteria in the bath water are propagated on a filter medium,
The TOC in bath water has been reduced by decomposing organic substances dissolved in bath water. However, after the installation of the circulating warm water bath, it takes about 10 to 14 days for the rise time of the aerobic purified bacteria to multiply, and there is a problem that the performance is not immediately exhibited immediately after the installation. In addition, treatment with hypochlorous acid or heat is necessary to disinfect the quality of bath water, the constitution of the bather, the bathing of the drug recipient, or the Legionella bacteria. There was a problem that the purification performance of bath water fluctuated greatly due to death or the like. In addition, in order to always maintain the aerobic purification bacteria in a good state, it is necessary to maintain the temperature of the bath water at about 35 ° C. during the operation of the circulating bath, so that the temperature of the bath water is maintained even when the bath is not bathed. Since it is necessary to maintain the temperature, it is necessary to always supply power to the heater, and there is a problem that energy saving is lacking.

In order to solve such a problem, Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open No. 296992 discloses a method of purifying organic acid-containing wastewater, in which an electrolyte salt is added to sewage and electrolysis is performed.
A method has been proposed in which an ozone treatment and an ultraviolet treatment are simultaneously performed to decompose organic acids in wastewater into carbon dioxide gas.

However, in this method, the organic matter in the wastewater which can be decomposed is only an organic acid and lacks versatility, and requires ozone treatment and ultraviolet (UV) treatment, which is complicated and lacks in workability. In addition, there is a problem that an ozone generator or the like is required, the apparatus becomes large, and the cost increases. Also, when removing organic matter from the circulating water bath, ozone may affect the human body in a tightly closed space such as a bathroom, and ultraviolet rays alone may dissolve organic carbon compounds containing nitrogen, such as dissolved proteins, which are dissolved in proteins. There was a problem that it could not be removed.

In Japanese Patent Application Laid-Open No. Hei 5-23673, when an organic wastewater is electrolytically treated to decompose an organic component, electrolysis is performed using a soluble anode and an insoluble anode as anodes, and the organic component is treated with the insoluble anode. A method has been proposed in which the decomposition product is decomposed and flocculated with the fine particles generated by dissolving the soluble anode to promote flocculation or sedimentation to facilitate separation of the decomposition product.

In this method, platinum or lead oxide is used as an insoluble anode. Platinum is a very stable electrode that is safe for the human body and the environment.However, because the oxygen overvoltage is not high, generally the anode potential is preciously polarized so that the oxygen will not reach the oxidation-reduction potential corresponding to the binding energy. There is a problem that generation occurs and this reaction becomes dominant, so that organic substances cannot be efficiently oxidized and decomposed. On the other hand, a lead oxide electrode generally has a higher oxygen overvoltage than platinum and has a higher decomposability of organic substances, but has poor adhesion to a base metal, so that the coated lead oxide layer is peeled off and flows out into water. In the treatment and the bath water purification treatment of the circulating warm water bath, there is a problem that it cannot be easily used in consideration of the secondary environmental pollution and the influence on the human body due to the lead oxide thus leaked out. Further, in this method, since a floc is generated because a soluble electrode such as aluminum is used, there is a problem that the floc treatment is required periodically and the workability is lacking.

To solve these problems, Japanese Patent Application Laid-Open No. 63-221888 discloses a doped SnO _2.
(Tin oxide) The organic matter in the solution is oxidatively decomposed and
An industrial sewage purification method by electrolysis for reducing C is disclosed. In this method, organic substances can be mineralized at a high electrode potential by using an electrode having a higher oxygen overvoltage than the lead dioxide electrode such as a tin oxide electrode, and when the same electrolytic current is applied because the oxygen overvoltage is higher than platinum. Can suppress the generation of oxygen, so that it can be decomposed at a low electrolytic voltage, and the energy efficiency can be increased.

For example, when each side has a size of 50 mm and a mesh size of 6 mm
Add square expanded titanium expanded metal to chlorothene
Etch in oxalic acid degreased in acetone and then boiled
After heating, place on a heating plate and heat to 450 ° C
And anhydrous SnCl in ethyl acetate_Four0.7mol / L
Spray the solution to Cl^-Doped with SnO_TwoFilm is formed
Prepared electrode, use this electrode as the anode and square
Sections of platinum-coated titanium expanded metal are shaded.
It is used as a pole. As an example, benzoic acid
(C₆H_FiveCOOH) 10ppm and 0.5N sodium sulfate
Um (Na_TwoSO_Four) 100 mA of electrolyte solution
At a constant current, a lead oxide (PbO) electrode was
Have a solution. Acid to reduce benzoic acid 10ppm to 0
Tin oxide (SnO _Two) The electrode is 5 hours, with lead oxide (PbO)
Is described as requiring 24 hours.

Further, naphthalenesulfonic acid (C ₁₀ H ₇ S)
When O ₃ H) is electrolyzed in a solution having a pH of 12.5, the concentration of naphthalenesulfonic acid becomes 30% of the initial value after 20 minutes.
It states that after 40 minutes it can be reduced to 8% to 3% after 2 hours and total carbon can be reduced to half of the initial value after 1 hour to 15% after 3.5 hours.

[0013]

However, in the above-described conventional oxidative decomposition method by electrolysis, the organic particles need to be captured near the electrode, and the organic particles that are not easily ionized are not captured near the positively polarized electrode. However, there is a problem that oxidative decomposition by oxidization is difficult.

In the decomposition method disclosed in JP-A-63-221888, the decomposed organic substances are naphthalenesulfonic acid, benzoic acid and the like, which are substances which are easily ionized by adjusting the pH in a solution. Yes, these ionic particles are trapped near the positively polarized SnO ₂ electrode and are oxidatively decomposed at high potential. However, organic compounds, such as proteins, which do not easily ionize completely in water do not respond to the positively polarized electrode even if the electrode is positively polarized, and it is difficult to capture the anode, and the decomposition efficiency is extremely low, making practical application difficult. There was such a problem.

Therefore, it is difficult to demineralize proteins in the bath water in the circulating warm bath by electrolysis and to demineralize and remove proteins that are eutrophic substances in wastewater discharged from food factories and marine processing plants. . In addition, in this conventional decomposition method, it is necessary to make the pH of the solution alkaline in order to ionize these organic substances, and to release these electrolyzed treated water, it is necessary to further perform a neutralization treatment, thereby saving labor. However, there is a problem that it is not easy to operate, and it requires a large amount of equipment investment.

The present invention solves the above-mentioned conventional problems, and decomposes an organic substance that is not completely ionized, such as a nitrogen-containing organic compound such as a protein, at a low electrolysis voltage to remove TOC in a short time and to reduce consumption. Providing a highly convenient decomposition electrode for organic sewage, which does not require a neutralization treatment of the treated water and does not generate scum, and a nitrogen-containing organic sewage using the decomposition electrode of the present invention. The treatment rate is extremely high, the provision of a method for decomposing organic sewage with excellent energy saving and excellent workability of maintenance management, and the decomposition electrode of the present invention can be used to treat compact, nitrogen-containing organic sewage at a high treatment rate. It is an object of the present invention to provide a device for decomposing organic sewage, which does not generate scum or the like, is easy to maintain, and has excellent energy saving.

[0017]

In order to solve this problem, an organic sewage decomposition electrode according to the present invention has a structure in which an electrode substrate is coated on its surface with a trapping material for trapping a nitrogen-containing organic compound. ing.

As a result, organic substances which are difficult to completely ionize, such as nitrogen-containing organic compounds such as proteins in organic sewage, can be decomposed at a low electrolysis voltage and TOC can be removed in a short period of time. In addition, it is possible to realize a highly convenient organic wastewater decomposition electrode that does not require neutralization of treated water and does not generate scum or the like.

Further, the method for decomposing organic sewage of the present invention comprises a step of performing electrolysis in a nitrogen-containing organic sewage using a decomposition electrode coated with a nitrogen-containing organic compound with a trapping material as an anode. It is possible to decompose a nitrogen-containing organic compound that is difficult to ionize, such as a protein, at a high decomposition rate, and realize a method for decomposing organic sewage, which is excellent in energy saving and excellent in workability of maintenance work.

The decomposition apparatus for organic sewage of the present invention uses a decomposition electrode coated with a trapping material for trapping a nitrogen-containing organic compound in nitrogen-containing organic sewage as an anode. In addition to being able to decompose nitrogen-containing organic compounds such as proteins that are difficult to ionize at high efficiency in a place, an organic wastewater decomposer that is easy to maintain and manage and has excellent energy saving can be realized.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The decomposition electrode for organic sewage according to claim 1 is a decomposition electrode in which the surface of an electrode substrate is covered with an electrode coating material, and the surface of the electrode coating material has organic sewage water. The structure is coated with a trapping material that traps nitrogen-containing organic compounds. With this trapping material that traps nitrogen-containing organic compounds, particles that are difficult to completely ionize, such as proteins in organic wastewater, are trapped near the electrodes. This has the effect that the nitrogen-containing organic compound can be oxidatively decomposed at an extremely high decomposition rate.

The decomposition electrode for organic sewage described in claim 2 has a configuration in which the electrode coating material is formed of an electrode material having an oxygen overvoltage higher than that of platinum.
It has the effect of easily oxidizing and decomposing the nitrogen-containing organic compound trapped in the vicinity of the electrode and gasifying it.

According to a third aspect of the present invention, in the electrode for decomposing organic sewage, the electrode coating material is at least one element selected from the group consisting of antimony, chlorine, molybdenum, tungsten, niobium, and tantalum. Since the composition is a mixture doped with, the nitrogen-containing organic compound trapped in the vicinity of the electrode can be more effectively oxidized and decomposed and gasified at a low decomposition voltage, thereby improving the reliability of the electrode. Has the effect of being able to.

According to a fourth aspect of the present invention, there is provided the electrode for decomposing organic sewage according to any one of the first to third aspects, wherein the electrode substrate is made of titanium, zirconium, niobium, niobium, tantalum or an alloy thereof. Since it is composed of any one of them, it has the effect of significantly improving the durability of the decomposition electrode in addition to the effect obtained in any one of claims 1 to 3.

According to a fifth aspect of the present invention, there is provided an electrode for decomposing organic sewage, wherein the trapping material is made of platinum, platinum oxide, or a protein-adsorbing polymer compound in any one of the first to fourth aspects. This has the effect of adsorbing proteins and oxidizing and decomposing the adsorbed proteins at a high potential, in addition to the effects obtained in any one of claims 1 to 4.

The electrode for decomposing organic sewage described in claim 6 has a structure in which the capturing material is coated on the electrode coating material via the support in any one of claims 1 to 5. Accordingly, the distance between the electrode base material and the trapping material can be controlled, and the electrolysis can be stably performed, so that the electrolysis can be efficiently promoted.

According to a seventh aspect of the present invention, in the method for decomposing organic sewage, an anode comprising the decomposition electrode according to any one of the first to sixth aspects and a cathode are disposed in the nitrogen-containing organic sewage. Since the anode and the cathode are energized to decompose the nitrogen-containing organic compound by an electrochemical reaction, the amount of power consumption is large, the neutralization of the treated water is not required, and scum or the like is not required. This has the effect that processing can be performed that does not generate.

The organic sewage decomposition apparatus according to claim 8 is an electrolytic tank for storing organic sewage to which nitrogen-containing organic sewage and a supporting electrolyte are added, and an electrolytic tank provided in the electrolytic tank for electrolyzing the organic sewage. An anode composed of the decomposition electrode according to any one of to 6 to 6, a cathode, and a voltage application unit for causing a current to flow between the anode and the cathode for electrolysis, so that the configuration includes: It has the effect of suppressing the generation of oxygen and efficiently oxidatively decomposing nitrogen-containing organic compounds.

In the organic sewage decomposition apparatus according to the ninth aspect, in the eighth aspect, the cathode is formed of platinum, platinum oxide, or a stainless steel material. It has the effect of being able to decompose a nitrogen-containing organic compound that is compatible with materials and has excellent durability, and has excellent flexibility.

Next, the decomposition electrode for organic sewage in the embodiment of the present invention will be specifically described.

(Embodiment 1) FIG. 1 is a structural diagram of an electrode for decomposing organic sewage in Embodiments 1 and 2 of the present invention.
In FIG. 1, 1 is an electrode substrate, 2 is an electrode coating material, and 3 is a trapping material. In the first embodiment, the length is 10 mm and the width is 10 m
A commercially available titanium plate having a thickness of 0.5 mm and a thickness of 0.5 mm was degreased with acetone, etched with a hot oxalic acid solution, further washed with pure water and dried to obtain an electrode substrate 1. A solution prepared by dissolving tin chloride and antimony chloride in ethanol at a weight ratio of 100: 1 is applied to the electrode substrate 1, dried and baked at 550 ° C. for 10 minutes. This operation is repeated to obtain a 3 μm-thick valence controlling agent. An electrode covering material 2 made of doped (hereinafter, doped) tin oxide was formed. The valence controlling agent contains at least one element of antimony, chlorine, molybdenum, tungsten, niobium, and tantalum. Next, chloroplatinic acid was dissolved in a butanol solution to obtain a platinum concentration of 0.01 m.
ol / L of a platinum solution, applied to the electrode coating material 2, dried and baked at 550 ° C. for 10 minutes to form a porous platinum coating on the doped tin oxide doped electrode coating material 2. A coating on which an oxide layer was formed was formed to obtain a decomposition electrode for organic wastewater.

(Embodiment 2) As shown in FIG. 1, in Embodiment 2, the height is 10 mm, the width is 10 mm, and the thickness is 0.5 m.
m, a commercially available titanium plate was degreased with acetone, etched with a hot oxalic acid solution, further washed with pure water and dried to obtain an electrode substrate 1.

A solution prepared by dissolving tin chloride and antimony chloride in ethanol at a weight ratio of 100: 1 is applied to the electrode substrate 1.
After drying, baking was performed at 550 ° C. for 10 minutes. This operation was repeated to form an electrode covering material 2 made of doped tin oxide having a thickness of 3 μm. The capturing material 3 made of platinum was formed using an ammonium phosphate containing chloroplatinic acid and a sodium phosphate bath to obtain an electrode for decomposing organic sewage. The distribution of platinum, the average thickness, and the lamination state of platinum on the electrode covering material 2 made of doped tin oxide of Embodiments 1 and 2 were confirmed using a high-power scanning electron microscope.

(Embodiment 3) FIG. 2 is a structural view of a decomposition electrode having a support of organic sewage in Embodiment 3 of the present invention. 1 is an electrode substrate, 2 is an electrode covering material, 3 is a capturing material, 4 is a support, and 5 and 6 are titanium plates for fixing. As shown in FIG. 2, in the third embodiment, the height is 12 mm,
A commercially available titanium plate having a width of 12 mm and a thickness of 0.5 mm was degreased with acetone, etched with a hot oxalic acid solution, further washed with pure water and dried to obtain an electrode substrate 1. A solution prepared by dissolving tin chloride and antimony chloride in ethanol at a weight ratio of 100: 1 was applied to the electrode substrate 1, dried, and baked at 550 ° C. for 10 minutes. This operation was repeated to form an electrode covering material 2 made of doped tin oxide having a thickness of 3 μm. Next, square mesh titanium having a side of 12 mm (a titanium wire having a wire diameter of 10 μm knitted at intervals of 100 μm) was degreased with acetone, etched with a hot oxalic acid solution to roughen the surface, and further washed with pure water. The support was dried after drying. In addition, a polystyrene homopolymer (membrane, 18 (1), 54 (199)
3) is immersed in a solution obtained by dispersing the above in a solvent to form a slurry,
A styrene homopolymer was fixed on the mesh-like titanium as the support 4. The support 4 provided with the polymer adsorbent as the trapping material 3 thus produced was fixed to the electrode substrate 1 as follows. That is, the electrode coating material 2 made of tin oxide doped with a width of about 1 mm from the outer edge of the electrode substrate 1 on which the electrode coating material 2 is formed with the doped tin oxide
To expose the titanium metal of the ingot, to join the support 4 and the electrode substrate 1 so that their outer edges coincide with each other, and to further firmly fix the support 4 and the electrode substrate 1 to a width of 1 mm.
A rectangular parallelepiped titanium plate 5 having a length of 12 mm and a thickness of 0.5 mm
And a 1 mm wide, 10 mm long, 0.5 mm thick rectangular parallelepiped titanium plate 6 is joined by joining the edges of the four sides of the support 4 and the electrode substrate 1, and is electrically welded from the end of the electrode substrate 1. 1
mm portion was covered with titanium metal, and the support 4 and the electrode substrate 1 were firmly joined to obtain an organic sewage decomposition electrode.

The styrene homopolymer of Embodiment 3 was confirmed by a transmission electron microscope, and it was confirmed by a transmission electron microscope that the styrene homopolymer was present in a uniformly dispersed state on the support 4 made of mesh titanium.

(Embodiment 4) FIG. 3 is a schematic configuration diagram of a nitrogen-containing organic decomposition apparatus according to Embodiment 4 of the present invention. In FIG. 3, reference numeral 7 denotes an electrolytic tank containing a solution 11 containing nitrogen-containing organic carbon, and reference numeral 8 denotes a decomposition electrode which is immersed in the solution 11 in the electrolytic tank 7 and forms a pair with the cathode 9 and serves as an anode.
The cathode 9 is made of platinum, platinum oxide, or a stainless material. Reference numeral 10 denotes a voltage application unit for applying a current to the decomposition electrode 8 and the cathode 9, and the solution 11 may be any solution as long as it contains organic carbon containing nitrogen. It corresponds to wastewater discharged from processing plants, fishery processing plants, breweries, livestock farms, human waste treatment, and sewage treatment equipment.

[0037]

Next, the method for decomposing organic sewage of the present invention will be described in detail with reference to examples. The anode obtained in Embodiment Modes 1 to 3 was used as an anode serving as a decomposition electrode.

As a sample solution, skim milk powder was used as a protein to be decomposed, and this was diluted with distilled water to a concentration of 25 mg / L, and potassium nitrate was added to the solution to adjust the conductivity of the solution to 1000 μS / cm. At this time, the TOC measurement value by the TOC meter was 18 mg / L. This solution was used as a sample solution in the following Examples and Comparative Examples.

The following comparative electrode was prepared as a comparative example. (Comparative electrode sample 1) Length 10 mm, width 10 mm, thickness 0.
A 5 mm commercially available platinum plate was used as Comparative electrode sample 1.

(Comparative electrode sample 2) 10 mm long and 10 m wide
A commercially available titanium plate having a thickness of 0.5 mm and a thickness of 0.5 mm is degreased with acetone, etched with a hot oxalic acid solution, further washed with pure water, and dried.
A solution dissolved in ethanol at a weight ratio of 0: 1 was applied to the substrate, dried, and baked at 550 ° C. for 10 minutes. This operation was repeated to form an electrode covering material 2 made of doped tin oxide having a thickness of 3 μm.

The current-potential relationship between the decomposition electrode and the comparative electrode was measured by the following method, and the oxygen overvoltage of the electrode was evaluated. That is, 0.1 mol / L in a glass container
A sulfuric acid solution is added, one of the decomposition electrode and the reference electrode described above is used as an anode, and a platinum plate having an area of 10 cm ² is used as a cathode. The electrode interval is maintained at 0.5 cm and the electrolytic system is passed without a diaphragm. The potential of the anode is regulated by a potentiostat with respect to a reference electrode (silver-silver chloride electrode (Ag / AgCl)), and a constant speed from immersion potential to 4 V (vsAg / AgCl) at a scanning speed of 10 mV / sec. , And the relationship between the current and the potential was obtained. From this, the oxygen overvoltage (η) of each electrode and the slope of Tafel were obtained.

That is, the oxygen overpotential (η) can be obtained by obtaining a potential at a current density of 0.1 mA / cm ² for each electrode in the sample solution, and the slope of Tafel is a predetermined value as shown in (Equation 1). 2 points (2 points determined by current density and potential)
It is given by finding the slope between them. The slope of this Tafel is 1 decad from the current density of 0.1 mA / cm ² .
This is for estimating the magnitude of the oxygen overvoltage (η) when it becomes greater than or equal to e, and it can be estimated that the oxygen overvoltage (η) is also large if the slope of Tafel increases.

[0043]

(Equation 1)

Here, E2: current density j = 1 mA / cm
Anode potential at ² ; E1: current density j = 0.1 mA / cm ²
, And the logarithmic logarithm of the current density j2, log10 (j1): the logarithm of the current density j1. The results are shown in (Table 1).

[0045]

[Table 1]

As is apparent from the above, the oxygen overvoltage (η) of the electrode of the first to third embodiments or the comparative electrode sample 2 indicates a potential of 2.5 V (vsAg / AgCl), while the platinum of the comparative electrode sample 1 The electrode was at 1.48 V, indicating that the doped tin oxide electrode exhibited a high oxygen overpotential (η). Also, in the current density region of j = 1 mA / cm ² or more, it can be seen from the slope of Tafel that the oxygen overvoltage (η) is larger in the electrodes of the first to third embodiments or the comparative electrode sample 2 than the comparative electrode sample 1. Note that, as described above, the oxygen overvoltage (η) is a potential at a current density of 0.1 mA / cm ² .

(Example 1) The decomposition electrode of Embodiment 1 was used as an anode, and platinum having twice the area of the anode was used as a cathode. 200 mL of the sample solution was stirred with a magnetic stirrer, and the distance between the electrodes was 5 mm. Electrolysis was performed for 10 hours with a direct current having a density of 10 mA / cm ² .

(Comparative Example 1) The thickness of each side of the anode was 10 mm and the thickness was 0.1 mm.
Using a 3 mm platinum electrode, 200 ml of the above sample solution was stirred with a magnetic stirrer and the distance between the electrodes was 5 m.
and electrolysis at a direct current of 10 mA / cm ² for 10 hours.

(Comparative Example 2) A comparative electrode sample 1 was used as an anode, and a platinum electrode having a side of 10 mm and a thickness of 0.3 mm was used as a cathode. Electrolyzed for 10 hours.

(Example 2) Using the decomposition electrode of Embodiment 2 as an anode, platinum having twice the area of the anode as a cathode, and 200 mL of the above sample solution being stirred with a magnetic stirrer, a distance between the electrodes of 5 mm and 10 mA For 3 hours.

(Example 3) The polarized electrolysis of Embodiment 3 was used as an anode, and platinum having twice the area of the anode was used as a cathode. 200 mL of the sample solution was stirred with a magnetic stirrer, and the distance between the electrodes was 5 mm and 10 mA. For 3 hours.

The above results (Table 2) are shown in FIG.

[0053]

[Table 2]

In Table 2 and FIG. 4, the TOC removal rate (%) was obtained by (Equation 2).

[0055]

(Equation 2)

Here, TOC (i) is the TOC (mg / L) of the sample solution before electrolysis, and TOC (t) is the TOC (mg / L) of the sample solution after electrolysis for t hours.

The TOC residual rate (%) was determined by (Equation 3).

[0058]

(Equation 3)

As is clear from FIG. 4, the residual ratio of 50% and 43%, ie, 50% and 67%, in the platinum electrode of Comparative Example 1 and the doped tin oxide electrode of Comparative Example 2 after 10 hours of electrolysis.
% Of the TOC removal rate, but 97% TOC removal was achieved by electrolysis for 10 hours in the electrode formed by sintering porous platinum on the doped tin oxide-coated titanium electrode of Example 1. You can see that there is. In addition, from Table 2, when electrolysis was performed for 3 hours using the electrode prepared by the method of forming a porous layer by another method (Examples 2 and 3), the TOC removal rate equivalent to that of Example 1 was obtained. Has been obtained. Further, when electrolysis is performed for 3 hours, the TOC removal amount is about 1.4 to 2 times that of the doped tin oxide electrode and the platinum electrode.

Furthermore, in this example, the concentration of skim milk powder was 25
mg / L and the initial TOC concentration was 18 mg / L. When the protein concentration was higher than this, it became clear that the area of the anode and the cathode should be increased in proportion to the concentration.

[0061]

As described above, according to the present invention, an organic sewage decomposition electrode having the following excellent effects, an organic sewage decomposition method using the same, and an organic sewage decomposition apparatus using the same are realized. You can do it.

According to the decomposition electrode for organic sewage described in claim 1, particles that are difficult to completely ionize, such as proteins in organic sewage, are captured in the vicinity of the electrode by the capturing material that captures nitrogen-containing organic compounds. This makes it possible to oxidatively decompose nitrogen-containing organic compounds at an extremely high decomposition rate.

According to the decomposition electrode for organic sewage described in claim 2, in addition to the effects obtained in claim 1, the nitrogen-containing organic compound trapped in the vicinity of the electrode can be easily oxidized and decomposed to gasify. it can.

According to the decomposition electrode for organic sewage described in claim 3, in addition to the effects obtained in claim 1 or 2, the nitrogen-containing organic compound trapped near the electrode at a low decomposition voltage can be more effectively used. Because it can be oxidized and decomposed and gasified,
The reliability of the electrode can be improved. In addition, energy saving can be improved.

According to the decomposition electrode for organic sewage described in claim 4, in addition to the effect obtained in any one of claims 1 to 3, the durability of the decomposition electrode can be significantly improved. .

According to the decomposition electrode for organic sewage described in claim 5, in addition to the effects obtained in any one of claims 1 to 4, the protein is adsorbed and the adsorbed protein is converted to a high electrode potential. Can be oxidatively decomposed. Since proteins and the like are decomposed with high efficiency, generation of scum and the like can be significantly reduced, and the apparatus can be made compact.

According to the decomposition electrode for organic sewage described in claim 6, in addition to the effect obtained in any one of claims 1 to 5, the distance between the electrode substrate and the trapping material can be controlled and Since the electrolysis can be stably performed, the electrolysis can be efficiently promoted.

According to the method for decomposing organic sewage described in claim 7, it is possible to carry out a treatment which requires a large amount of treatment with respect to power consumption, does not require neutralization treatment of treated water, and does not generate scum or the like.

According to the organic sewage decomposition apparatus described in claim 8, the generation of oxygen can be suppressed and the nitrogen-containing organic compound can be efficiently oxidatively decomposed.

According to the organic sewage decomposition apparatus according to the ninth aspect, in addition to the effects obtained in the eighth aspect, the cathode can be made of a nitrogen-containing organic compound having good compatibility and excellent durability regardless of the material of the anode. It can be disassembled and has excellent flexibility.

[Brief description of the drawings]

FIG. 1 is a structural diagram of a decomposition electrode of organic sewage in Embodiments 1 and 2 of the present invention.

FIG. 2 is a structural diagram of a decomposition electrode having a support of organic sewage in Embodiment 3 of the present invention.

FIG. 3 is a schematic configuration diagram of a nitrogen-containing organic carbon decomposition apparatus according to Embodiment 4 of the present invention.

FIG. 4 is a diagram showing the relationship between electrolysis time and TOC residual rate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrode base material 2 Electrode coating material 3 Capture material 4 Support body 5, 6 Titanium plate 7 Electrolysis tank 8 Decomposition electrode 9 Cathode 10 Voltage application part 11 Solution

Claims (9)

[Claims] 1. A decomposition electrode in which the surface of an electrode substrate is covered with an electrode coating material, wherein the surface of the electrode coating material is coated with a capturing material for capturing nitrogen-containing organic compounds in organic sewage. An electrode for decomposing organic sewage. 2. The decomposition electrode for organic sewage according to claim 1, wherein said electrode coating material is formed of an electrode material having an oxygen overvoltage higher than that of platinum. 3. The electrode coating material according to claim 1, wherein the electrode coating material is a mixture of tin oxide and at least one element selected from the group consisting of antimony, chlorine, molybdenum, tungsten, niobium, and tantalum. Of wastewater from organic wastewater. 4. The electrode substrate according to claim 1, wherein said electrode substrate is made of any one of titanium, zirconium, niobium, tantalum, and an alloy thereof.
An electrode for decomposing organic sewage as described in the item. 5. The electrode for decomposing organic sewage according to claim 1, wherein said trapping material is made of platinum, platinum oxide, or a protein-adsorbing polymer compound. 6. The electrode for decomposing organic sewage according to claim 1, wherein said trapping material is coated on said electrode coating material via a support. 7. An anode comprising the decomposition electrode according to any one of claims 1 to 6 in a nitrogen-containing organic sewage,
A method for decomposing organic sewage, comprising disposing a cathode, energizing the anode and the cathode, and decomposing organic substances by an electrochemical reaction. 8. An electrolytic tank for storing an organic sewage to which nitrogen-containing organic sewage and a supporting electrolyte are added, and an electrolytic tank provided in the electrolytic tank for electrolyzing the organic sewage. An organic sewage decomposition apparatus, comprising: an anode comprising the decomposition electrode described in 1); a cathode; and a voltage applying unit for causing a current to flow between the anode and the cathode to perform electrolysis. 9. The cathode according to claim 8, wherein said cathode is formed of platinum, platinum oxide or a stainless steel material.
Organic sewage decomposition apparatus described in 1.