KR20050090700A - Metal mixed oxide electrode and making method of the same - Google Patents

Abstract

TECHNICAL FIELD This invention relates to the metal mixed oxide electrode used when electrolytically treating wastewater, and its manufacturing method.

The present invention is an electrode substrate; Iridium (Ir) compounds Ruthenium (Ru) compounds Tin (Sn) compounds and manganese (Mn) compounds Titanium (Ti) compounds Molybdenum (Mo) compounds Tantalum (Ta) compounds Zirconium (Zr) compounds At least one selected from organic solvents The mixed coating solution is applied to the electrode substrate and dried, and the first heat treatment is performed 4 to 15 times, followed by a second heat treatment.

Description

Metal mixed oxide electrode and its manufacturing method {Metal Mixed Oxide Electrode And Making method of The Same}

The present invention relates to a metal mixed oxide electrode and a method for manufacturing the same, and more particularly, to a metal mixed oxide electrode and a method for producing the same for improving the durability and electrolytic performance of the electrode used in the electrolytic treatment.

In general, as the industry develops, the discharge amount of domestic sewage and industrial wastewater is increasing year by year, and the major pollutants are also changed into organic toxic compounds emitted from industrial wastewater in conventional domestic sewage.

However, existing treatment methods such as ozone treatment, activated carbon adsorption, Fenton's reagent, biochemical treatment, etc. are difficult to effectively treat toxic wastewater. In particular, biochemical treatment methods known to be effective treatment techniques for the decomposition of various pollutants require a large treatment area and a long reaction time, and are difficult to apply to toxic wastewater treatment in which microorganisms are killed.

Complementing the disadvantages of the existing wastewater treatment methods, and has been applied to many reports and the actual wastewater treatment process for the electrolysis using the electrochemical oxidation and reduction reaction in the treatment of difficult decomposition toxic wastewater.

Water treatment by electrolysis has the advantage that the consumption of chemicals used in the treatment is much smaller than the biochemical treatment or activated carbon treatment, and the operation is simple because the control of wastewater treatment conditions and reaction temperature depends only on voltage and current. Have In addition, the treatment time of the wastewater varies slightly depending on the type and sex of the wastewater, but is generally short, and it is possible to continuously treat the wastewater, and total nitrogen, cyanide, and COD in the wastewater such as plating wastewater, dyeing wastewater, and livestock wastewater. Various types of contaminants such as BOD, etc. can be processed in a batch without a separate treatment device or process.

However, since wastewater decomposition by electrolysis is mainly performed by the electrode surface reaction using a conductive anode and a cathode, it is important to select an appropriate electrode for the anode and the cathode. In general, electrolysis of aqueous solution is a reaction in which hydrogen is generated at the cathode and oxygen is generated at the anode. That is, in the positive electrode, the generation of oxygen by the oxidation of water or OH ⁻ occurs competitively, and if it is not a very acidic solution, the reaction potential of oxygen generation is lower than that of the chlorine generation reaction, resulting in a thermodynamically unstable reaction. Therefore, the electrode used as the anode should use a large overpotential for oxygen generation and a small overpotential for chlorine generation. Such high oxygen overvoltage anode materials include platinum-based elements such as Pt, Ru, Ir, etc., but have a disadvantage of being very expensive.

Therefore, there has been a demand for the development of electrodes having a relatively low cost while having excellent oxygen overvoltage and durability of platinum-based elements. The study of anode materials using metals such as titanium, zirconium, tantalum, molybdenum, columbium, tungsten, etc. as substitutes for platinum-based elements was conducted in the mid-20th century. Was done vigorously.

These metals have high electrical conductivity and excellent durability in an acidic or alkaline aqueous solution, but have exhibited a problem of rapidly increasing resistance when electricity is applied.

This is because an oxide film is formed on the surface of the electrode, and eventually the performance as an electrode is lost due to the growth of the oxide film. In the early 1950s, research on the oxide catalyst electrode having conductivity by injecting heterogeneous elements into the TiO ₂ lattice using the semiconducting properties of the oxide film of TiO ₂ formed on the surface of titanium began. Diamond Shamrock Technology Co., Ltd. As a result, the DSA (Dimensionally Stable Anode) electrode made by incorporating TiO ₂ into RuO ₂ was developed and commercialized.

However, the DSA electrode has a problem in that RuO ₂ is eluted to RuO ₄ by oxygen generated at the anode, thereby losing catalytic activity.

In order to solve such a problem, a general method of manufacturing an insoluble oxide catalyst electrode is a method of manufacturing an electrode by forming a coating layer by brushing or applying a metal chloride, nitride, hydrate, etc. providing a noble metal element on the surface of the electrode and forming a coating layer The activity varies depending on the type, ratio, heat treatment temperature, time of the added element, pretreatment method of the electrode, and the like.

In US Pat. No. 3,711,385, an electrode was prepared by directly coating a platinum group element on metal titanium. US Pat. No. 4,528,084 coated the electrode by pyrolysis by adding hydrochloric acid (HCl) to iridium, rhodium, and ruthenium compounds on a titanium base. It was. In addition, U.S. Patent No. 5,587,058 specifies the preparation of an electrode having a coating solution of ₂₀ to 28 mol% IrO ₂ and ₂ to 6 mol% RuO ₂ mainly based on 70 to 75 mol% of TiO ₂ on a titanium matrix.

In addition, Korean Patent No. 403,235 proposes a method of preparing a coating liquid based on ruthenium-iridium-titanium and pretreatment of the electrode by etching hydrochloric acid without using an existing substrate etching method, oxalic acid.

In addition, Korean Patent Application No. 10-2000-7014261 discloses H ₂ PtC1 ₆ -RuCl ₄ -SnCl ₄ . A method for preparing a coating liquid and a coating method as main components is provided.

However, the characteristics of these electrodes only provide the coating composition of the electrode having similar properties as the electrode using platinum group element, but the method of pretreatment of the coating base material by hydrochloric acid etching at 80 ° C is complicated and relatively expensive platinum-based chloride is used as starting material. There is a problem to use.

Therefore, the present invention has been made in view of the problems of the prior art, the object of which is more than twice the efficiency of the conventional electrode for water treatment electrolysis, such as total nitrogen, cyan, COD, BOD, etc. The present invention provides a metal mixed oxide electrode for improving the durability and performance of an electrolysis electrode for water treatment, which is inexpensive to remove at a high decomposition rate, and an electrolysis electrode used for electrolysis of other liquids, and a method of manufacturing the same. .

In order to achieve the above object, the present invention is an electrode substrate; Iridium (Ir) compounds Ruthenium (Ru) compounds Tin (Sn) compounds and manganese (Mn) compounds Titanium (Ti) compounds Molybdenum (Mo) compounds Tantalum (Ta) compounds Zirconium (Zr) compounds At least one selected from organic solvents It provides a metal mixed oxide electrode, characterized in that consisting of a coating layer formed by applying a mixed coating solution to the electrode substrate and dried a plurality of times the first heat treatment after repeated processes.

And, the present invention comprises the steps of (a) preparing an electrode substrate; (b) Iridium (Ir) compounds Ruthenium (Ru) compounds Tin (Sn) compounds and manganese (Mn) compounds Titanium (Ti) compounds Molybdenum (Mo) compounds Tantalum (Ta) compounds Zirconium (Zr) compounds Mixing with an organic solvent to obtain a coating solution; (c) forming a coating layer on the electrode substrate using the coating solution, (c1) applying the coating solution to the electrode substrate and drying it, (c2) heat treatment, (c3) (c3) (c1), ( repeating step c2) to form a coating layer having a thickness capable of transferring current required for electrolysis without the coating layer peeling off the substrate; And (d) provides a method for producing a metal mixed oxide electrode comprising the step of the final heat treatment.

The said electrode substrate is titanium, and the fine unevenness | corrugation is formed in the surface.

At least one selected from among the iridium (Ir) compound ruthenium (Ru) compound tin (Sn) compound and manganese (Mn) compound titanium (Ti) compound molybdenum (Mo) compound tantalum (Ta) compound zirconium (Zr) compound Chloride, and the organic solvent is isopropyl alcohol.

The heat treatment of step (c2) is carried out for 10 to 30 minutes at 400 ~ 700 ℃ temperature in the oxidizing atmosphere, the final heat treatment of step (d) is carried out for 3 to 6 hours at a temperature of 400 ~ 700 ℃ in an oxidizing atmosphere .

The present invention made as described above provides a method for lowering the surface potential of the electrolytic electrode by coating iridium, ruthenium, tin, manganese, titanium, molybdenum, tantalum, zirconium, etc., having excellent electrical conductivity on a titanium substrate having fine unevenness.

The heat treatment of step (c2) is performed to impart a bonding force between the coating liquid dried at a low temperature and the substrate, and the final heat treatment is to give sufficient bonding strength and surface strength by sufficiently growing the coated oxide particles.

The reason for limiting the multi-coating dry heat treatment to 4 to 15 in the step (c3) is as follows. That is, from the composition of Table 1 and the experimental results of Table 2, it can be seen that the wastewater decomposition efficiency is low in the case of 4 and 15 coatings, but the coating layer is not sufficiently developed when the coating is 4 or less. Therefore, the coating layer may be peeled off from the titanium substrate used as the coating base material during the electrolysis. If the number of coatings is 15 or more times, the electrical conductivity is lowered due to excessive growth of the oxide layer, and thus a high voltage is required.

That is, if the coating thickness is thick enough, coating may be performed with a small number of times. If the thickness of the coating layer is too thick and the electrical conductivity is low, current transfer for electrolysis is difficult, so that the coating layer may be smoothly electrolyzed without peeling. The thickness should be secured.

In addition, titanium is selected as an electrode material, and iridium, ruthenium, tin, manganese, titanium, molybdenum, tantalum, zirconium, and the like are selected as coating materials. That is, since the titanium substrate has acid resistance and chemical resistance and has a relatively high melting point (1668 ° C.), the titanium substrate has an advantage of not deteriorating due to temperature change during electrode coating and heat treatment by pyrolysis.

However, when titanium is used directly as an anode material, the titanium surface is anodized by application of current, and a titanium dioxide (TiO ₂ ) layer, which is an oxide film of metal titanium, is formed so that no current flows. Therefore, elements such as iridium, ruthenium, tin, molybdenum, tantalum, zirconium, etc. are added to increase the electrical conductivity by injecting a heterogeneous element into the crystal lattice of titanium dioxide, an oxide film.

(Example)

Hereinafter, with reference to the accompanying drawings showing a preferred embodiment of the present invention described above in more detail.

1. First Example (See Specimens 1 to 17 in Tables 1 and 2)

Iripropyl alcohol, ruthenium chloride, tin chloride, and manganese chloride were weighed into the composition shown in Table 1 in 100 cc of isopropyl alcohol, and then dispersed and mixed for 1 hour using an ultrasonic disperser. Stir for 2 hours using a magnetic stirrer for complete dissolution of the dispersed coating solution. Titanium substrate cut to the appropriate size (5 × 10 cm) for pretreatment of the coating substrate is sandblasted to give fine concavities and convexities to the surface, and to clean the fine dust and contaminants present on the surface by using an organic solvent. After drying, dry in a hot air drying furnace at 100 ° C. until water is completely evaporated. The coating solution is applied onto the dried titanium substrate using a brush or spray, and then dried in a hot air drying furnace at 100 to 150 ° C. for 10 to 20 minutes. Heat treatment is performed for 10 to 20 minutes in an electric furnace at 400 to 700 ° C for a smooth bonding between the dried coating solution and the titanium surface. At this time, when the heat treatment time is excessively elapsed, an oxide layer may be grown on the titanium surface, and thus, an adverse effect of lowering the electrical conductivity of the electrode during repeated coating may occur.

After the heat treatment, the coating solution is applied to the cooled substrate again, and then dried after the heat treatment. And, this process is carried out a total of 6 to 10 times.

Final heat treatment for 3-6 hours at 400 ~ 700 ℃ to facilitate the growth of the oxide layer. At this time, the reason for limiting the temperature condition to 400 ~ 700 ° C is that the amorphous hydroxide layer on the surface of the metal titanium is transformed into anatase crystal structure with excellent electrical properties at the temperature of 400 ° C or higher, but is transformed back into the rutile structure at the temperature of 700 ° C or higher. Because the property is reduced. A manufacturing process of an oxide catalyst electrode such as titanium dioxide having such a structure is shown in FIG. 1.

2. Second Example (See Psalms 18-21 in Tables 1 and 2)

Titanyl chloride having a rutile crystal structure such as iridium chloride, ruthenium chloride, and tin chloride was weighed into 100 cc of isopropyl alcohol, and then weighed and added into the composition of Table 1, and then dispersed and mixed for 1 hour using an ultrasonic disperser. The following process is the same as the first embodiment.

3. Third Example (See Psalms 22-25 in Tables 1 and 2)

Tantalum chloride having a crystal structure such as iridium chloride, ruthenium chloride, and tin chloride was weighed into 100 cc of isopropyl alcohol, and weighed in the composition shown in Table 1, and then dispersed and mixed for 1 hour using an ultrasonic disperser. The following steps are the same as in the first embodiment.

4. Fourth Example (See Psalms 26-29 in Tables 1 and 2)

Iripropyl chloride, ruthenium chloride, tin chloride, zirconium chloride were weighed into 100 cc of isopropyl alcohol, and then dispersed and mixed for 1 hour using an ultrasonic disperser. The following steps are the same as in the first embodiment.

5. Fifth Example (See Specimen 30 to 32 in Tables 1 and 2)

Iripropyl chloride, ruthenium chloride, tin chloride and molybdenum chloride were weighed into 100 cc of isopropyl alcohol, and then dispersed and mixed for 1 hour using an ultrasonic disperser. The following steps are the same as in the first embodiment.

6. Sixth embodiment

Platinum electrode, IrO ₂ electrode, and the present invention are widely used as electrolytic electrode elements after preparing the ammonia nitrogen simulation liquid, which is a contaminant in the wastewater, for evaluating the characteristics of the electrode specimens formed in the first to fifth embodiments. The characteristics of the oxide catalyst electrode prepared by the above were compared with each other.

A simulation liquid with a concentration of about 500 ppm was prepared for the decomposition of ammoniacal nitrogen. 2 g of NH ₄ Cl and 7.5 g of NaCl were added to 1 L of distilled water, followed by stirring until the powder was sufficiently dissolved in the solution. At this time, the electrical conductivity of the mixed solution was 30mS. 50cc of the prepared simulation liquid is filled in a batch type reactor. Decomposition experiments were carried out by applying a constant current of 60 mA / cm ² for 8 minutes at each electrode reaction area of 5 × 4 cm. The results of the decomposition experiments are shown in Table 2.

As shown in Table 2, the electrode manufactured by changing the composition of iridium-ruthenium-tin-manganese, titanium, tantalum, zirconium, drying temperature, heat treatment time, etc. is up to 2 times or more than the widely used platinum or iridium electrode. Ammonia nitrogen decomposition efficiency was shown. This electrode is OCl, a powerful oxidizing agent in combination with the oxygen ions in the Cl ions in the aqueous solution formed at the electrode surface increases the chlorine generation level than the oxygen over-voltage to the decomposition of the ammonium nitrogen ^- it is due to form to convert NH ₃ into nitrogen gas .

7. Seventh embodiment

In order to evaluate the characteristics of the electrodes formed in Examples 1 to 5, after preparing a nitrate nitrogen simulation liquid which is a contaminant in the wastewater as follows, the characteristics of the platinum electrode, IrO ₂ electrode and the oxide catalyst electrode prepared according to the present invention Were compared with each other.

A simulation liquid with a concentration of about 350 ppm was prepared for the decomposition of nitrate nitrogen. 2 g of NaNO ₃ and 10 g of NaCl were added to 1 L of distilled water to give electrical conductivity, followed by stirring until the powder was sufficiently dissolved in the solution. At this time, the electrical conductivity of the mixed solution was 30mS. 50cc of the prepared simulation liquid is filled in a batch type reactor. Decomposition experiments were conducted by applying a constant current of 100 mA / cm ² for 25 minutes with each electrode reaction area of 6 × 5 cm. The results of the decomposition experiments are shown in Table 2.

8. Eighth Embodiment

In order to evaluate the characteristics of the electrodes formed in Examples 1 to 5, after the cyan simulation liquid, which is a contaminant in the wastewater, was prepared, the characteristics of the platinum electrode, the IrO ₂ electrode, and the oxide catalyst electrode prepared by the present invention were compared with each other. Compared.

A simulation liquid having a concentration of about 250 ppm was prepared for decomposition of the cyan component. NaCl 10g was added to give 1 cc of distilled water and CN-nitrate 2cc and electrical conductivity, and the mixture was stirred until the powder was sufficiently dissolved in the solution. At this time, the conductivity of the mixed solution was 30mS. 50cc of the prepared simulation liquid is filled in a batch type reactor. Decomposition experiments were conducted by applying a constant current of 60 mA / cm ² for 25 minutes with each electrode reaction area of 6 × 5 cm. The results of the decomposition experiments are shown in Table 2.

9. Ninth Embodiment

Platinum electrode, IrO ₂ electrode and oxide catalyst electrode prepared according to the present invention for the decomposition of Chemical Oxygen Demand (COD) in wastewater for the evaluation of the characteristics of the electrodes formed in the first to fifth embodiments Were compared with each other. A simulated liquid with a concentration of about 500 ppm was prepared for COD decomposition. 1 g of distilled water was added with 1 g of glucose and 10 g of NaCl to give conductivity, followed by stirring until the powder was sufficiently dissolved in the solution. At this time, the conductivity of the mixed solution was 30mS. 50cc of the prepared simulation liquid is filled in a batch type reactor. Decomposition experiments were conducted by applying a constant current of 60 mA / cm ² for 1 hour at each electrode reaction area of 6 × 5 cm. The results of the decomposition experiments are shown in Table 2.

Example Psalter Element added (Wt.%) Coating Recovery Drying temperature (℃) Heat treatment time (minutes) Final heat treatment temperature (℃) Final heat treatment time (hours) Ir Ru Sn Mn Ti Mo Ta Zr One One 25 25 25 25 6 100 10 400 3 2 25 25 25 25 6 100 10 500 5 3 25 25 25 25 6 100 10 600 5 4 25 25 25 25 6 100 10 700 5 5 30 20 25 25 6 100 10 500 5 6 20 30 25 25 6 100 10 500 5 7 10 40 30 20 6 100 10 500 5 8 20 40 20 20 6 100 10 500 5 9 30 30 20 20 6 100 10 500 5 10 25 25 25 25 10 100 20 500 6 11 25 25 25 25 10 150 10 500 6 12 25 25 25 25 10 150 10 500 5 13 25 25 25 25 10 80 20 500 5 14 25 25 25 25 15 100 10 500 5 15 25 25 25 25 15 150 10 500 5 16 25 25 25 25 4 100 10 500 5 17 25 25 25 25 4 150 10 500 5 2 18 25 25 25 25 6 100 10 500 5 19 10 40 30 20 6 100 10 500 5 20 20 40 20 20 6 100 10 500 5 21 30 30 20 20 6 100 10 500 5 3 22 25 25 25 25 6 100 10 500 5 23 10 40 30 20 6 100 10 500 5 24 20 40 20 20 6 100 10 500 5 25 30 30 20 20 6 100 10 500 5 4 26 25 25 25 25 6 100 10 500 5 27 10 40 30 20 6 100 10 500 5 28 20 40 20 20 6 100 10 500 5 29 30 30 20 20 6 100 10 500 5 5 30 25 25 25 25 6 100 10 500 5 31 10 40 30 20 6 100 10 500 5 32 20 40 20 20 6 100 10 500 5

Example Sixth embodiment Seventh embodiment Eighth Embodiment Ninth Embodiment division Ammonia Nitrogen Degradation Rate (%) Nitric Acid Nitrogen Degradation Rate (%) Cyan decomposition rate (%) COD decomposition rate (%) Psalter One 92 90 89 88 2 98 95 95 92 3 94 93 91 90 4 90 88 92 93 5 92 95 90 88 6 87 89 85 87 7 94 92 93 92 8 92 94 90 93 9 89 90 91 93 10 96 90 93 91 11 93 93 89 90 12 84 88 85 90 13 82 82 85 80 14 81 78 75 76 15 78 76 76 73 16 75 77 81 76 17 77 80 72 73 18 89 92 90 88 19 86 86 85 83 20 82 80 85 83 21 88 85 87 88 22 93 90 92 90 23 92 95 93 90 24 90 87 93 88 25 91 87 89 90 26 94 90 92 88 27 92 95 90 93 28 89 84 90 88 29 91 90 91 89 30 93 91 92 90 31 94 93 95 91 32 92 90 90 89 Platinum electrode 42 71 69 72 IrO ₂ electrode 48 54 58 60

As shown in Table 1, using the electrode material coated on the titanium substrate with a coating liquid using any one selected from manganese, titanium, molybdenum, tantalum, zirconium, with three components of iridium, ruthenium, tin as a main component, Table 2 As shown in FIG. 4, the results show that the ammonia nitrogen component, the nitrate nitrogen component, cyanide, COD, and the like are applied to the electrolytic treatment, and the decomposition rate is significantly higher than that of the conventional platinum electrode or iridium oxide electrode.

10. Decomposition process of ammonia nitrogen, nitrate nitrogen, cyanide and COD

As in the sixth to ninth embodiments, the chemical reaction process in the decomposition of ammonia nitrogen, nitrate nitrogen, cyanide, COD using the electrolysis electrode according to the present invention will be described as follows.

First, in the case of nitrate nitrogen, it is not directly converted to nitrogen, but is converted to nitrogen by chlorine (compound) formed at the anode and then discharged into the atmosphere through nitrite nitrogen in the middle and then to ammonia nitrogen.

These reactions occur at the same time, so it is difficult to distinguish the steps. However, when the chlorine content is insufficient, nitrate nitrogen is not converted to nitrogen and remains as ammonia, so NaCl (salt), which is an electrolyte and provides chlorine, must be supplied.

(1) NO ₃ ^- removal scheme

(A) Treating wastewater in an acid atmosphere

_{^{NO 3 - + 10H + + 8e}} - = NH 4 + + 3H 2 O E 0 = + 0.875volt

_{^{2NO 3 - + 12H + + 10e}} - = N 2 (g) + 6H 2 O E 0 = + 1.246volt

(B) Wastewater treatment in neutral and alkaline atmospheres

In the case of neutral and alkaline wastewater treatment, it is not converted directly from NO ₃ ⁻ to nitrogen gas but through the intermediate product NO ₂ ⁻ to NH ₃ or some N ₂ (g).

^{_{NO 3 - + H 2 O +}} 2e - = NO 2 - + 2OH -

^{_{NO 2 - + 2H 2 O +}} 3e - = (1/2) N 2 (g) + 4OH -

^{_{2NO 2 - + 3H 2 O +}} 4e - = N 2 O + 6OH -

^{_{NO 2 - + 5H 2 O +}} 6e - = NH 3 + 7OH -

^{_{NO 3 - + 3H 2 O +}} 5e - = (1/2) N 2 (g) + 6OH - ( general formula (3) + Formula 4)

^{_{NO 3 - + 6H 2 O +}} 8e - = NH 3 + 9OH - ( general formula (3) + Formula 6)

On the other hand, when NaCl is added to the electrolyte, Cl ₂ generated at the anode during electrolysis dissolves in the solution to form free chlorine according to formula (9) (solution of chlorine: 7,160 mg / L at 1 atm, 20 ° C.). ).

_{Cl 2 + H 2 O = HOCl} + H + + Cl - ( acidic atmosphere)

2NH ₃ + 3HOCl = N ₂ + 3HCl + 3H ₂ O

2NH ₃ + 3Cl ₂ = N ₂ + 6HCl (3 × (Formula 9) + (Formula 10))

By the way, if the solution is alkaline, the free chlorine exhibits an equilibrium relationship as in formula (12). The more stable the acidic HOCl form, the more alkaline the more stable the OCl ⁻ form (known as equilibrium at pH = 7.53).

^{OH - + HOCl = OCl - +} H 2 O

When Formula 9 is used again in a stable state in an alkaline atmosphere, it is the same as that of Formula 13.

_{^{Cl 2 + OH - = OCl -}} + H + + Cl - ( alkaline atmosphere)

Formula 10 does not distinguish between stable phases in acidic and alkaline atmospheres. When the chemical formula is rewritten in a stable state in a neutral and alkaline atmosphere, it is represented by Chemical Formula 14.

^{_{2NH 3 + 2OCl - = N 2}} + 2HCl + 2H 2 O

(2) CN ^- removal scheme

When electrolysis is performed using the electrolysis electrode according to the present invention, Cl ⁻ present in the waste water is reduced to Cl ₂ gas at the anode, and Cl ₂ gas is redissolved in the waste water to form OCl ⁻ . The cyan is removed by conversion to carbon dioxide and water with OCl ⁻ .

The role of the electrolysis electrode normally used in water treatment plants is to maximize the generation of Cl ₂ gas without dissociation. If a lot of Cl ₂ gas is generated, a large amount of OCl ⁻ is generated, resulting in higher processing efficiency. Depending on the material, the chlorine generation potential, the oxygen generation potential, the hydrogen generation potential, etc. have a constant value. The electrolysis electrode according to the present invention lowers the chlorine generation potential therein so that chlorine generation is better than other side reactions and hydrogen generation. will be.

Cyan is present in the form of M (CN) _n (typical NaCN) or in [M (CN) _m ] ^-n due to the presence of excess CN ⁻ , and the typical removal method is the chlorine-based oxidizing agent, which is a harmless CO Oxidize to ₂ and N ₂ .

Specific reaction processes are the same as in Formula 15 and Formula 16.

NaCN + NaOCl = NaCNO + NaCl

2NaCNO + 3NaClO + H ₂ O = 2CO ₂ + N ₂ + 2NaOH + 3NaCl

Although the chemical formula and cyanide removal method are already known, the method of removing cyanide in the present invention is NaCl component used as an electrolyte as Cl ₂ gas at the anode and is dissolved in wastewater (water) again depending on the pH, but OCl ^(neutral, alkaline), is converted to HOCl (acidic), the conversion of ^{OCl-(neutral,} alkaline), HOCl cyan (CN ^-) will come in combination with fly with nitrogen.

The reaction process is represented by the formula 17 and formula 18.

^{CN - + OCl - = CNO -} + Cl -

_{^{2CNO - + 3OCl - + H 2}} O = 2CO 2 + N 2 + 2OH - + 3Cl -

(3) COD removal scheme

COD is also removed using OCl ⁻ . Therefore, the process until OCl ⁻ is formed is omitted. However, since a variety of substances causing the COD is expressed briefly, such as the formula (19) and (20).

_{^{Organic pollutant + OCl - = CO 2}} + H 2 O + Intermediate

Organic + HOCl = Organic Oxidized + Cl ₂

Summarizing the above chemical reaction process, nitrate nitrogen and nitrite nitrogen are directly reduced at the anode to be ammonia nitrogen, and the ammonia nitrogen, cyanide and COD are formed by dissociation of chlorine generated at the cathode into the wastewater. OCl ^- to be switched to nitrogen or water, carbon dioxide, in conjunction with (or HOCl), this method is a processing method using the indirect oxidation method.

The present invention made as described above can be utilized as an anode replacement material of wastewater treatment process and plating process using electrolysis through the production method of oxide catalyst electrode of high efficiency, drinking water treatment system, anode for electrolysis, electric room It is expected to be used throughout life, such as dedicated anodes and seawater desalination anodes.

In the above, the present invention has been illustrated and described with reference to specific preferred embodiments, but the present invention is not limited to the above-described embodiments and the general knowledge in the technical field to which the present invention pertains without departing from the spirit of the present invention. Various changes and modifications will be made by those who possess.

1 is a process chart for explaining a method for producing a metal mixed oxide electrode according to the present invention.

Claims (10)

An electrode substrate; Iridium (Ir) compounds Ruthenium (Ru) compounds Tin (Sn) compounds and manganese (Mn) compounds Titanium (Ti) compounds Molybdenum (Mo) compounds Tantalum (Ta) compounds Zirconium (Zr) compounds At least one selected from organic solvents A coating layer having a thickness capable of transferring an electric current required for electrolysis without being separated from the substrate by repeating a process of coating and drying the mixed coating solution on the electrode substrate and performing a first heat treatment. A metal mixed oxide electrode, characterized in that consisting of. The metal mixed oxide electrode as claimed in claim 1, wherein the electrode substrate is a titanium substrate having fine irregularities formed on a surface thereof. The method of claim 1, wherein the iridium (Ir) compound ruthenium (Ru) compound tin (Sn) compound and manganese (Mn) compound titanium (Ti) compound molybdenum (Mo) compound tantalum (Ta) compound zirconium (Zr) compound selected from At least 1 type is chloride, The said organic solvent is isopropyl alcohol, The metal mixed oxide electrode characterized by the above-mentioned. The method of claim 1, wherein the first heat treatment is performed for 10 to 30 minutes at 400 ~ 700 ℃ temperature in an oxidizing atmosphere, the second heat treatment is performed for 3 to 6 hours at a temperature of 400 ~ 700 ℃ in an oxidizing atmosphere A metal mixed oxide electrode. (a) preparing an electrode substrate; (b) Iridium (Ir) compounds Ruthenium (Ru) compounds Tin (Sn) compounds and manganese (Mn) compounds Titanium (Ti) compounds Molybdenum (Mo) compounds Tantalum (Ta) compounds Zirconium (Zr) compounds Mixing with an organic solvent to obtain a coating solution; (c) to form a coating layer on the electrode substrate using the coating liquid, (c1) applying the coating solution to the electrode substrate and drying it; (c2) heat treatment, (c3) repeating steps (c1) and (c2) to form a coating layer having a thickness enough to transfer a current required for electrolysis without peeling the coating layer from the substrate; (d) final heat treatment; Method of producing a metal mixed oxide electrode comprising a. 6. The method of claim 5, wherein the electrode substrate is titanium. The method of claim 5, wherein the electrode substrate has fine irregularities formed on a surface thereof. The method of claim 5, wherein the iridium (Ir) compound ruthenium (Ru) compound tin (Sn) compound and manganese (Mn) compound titanium (Ti) compound molybdenum (Mo) compound tantalum (Ta) compound zirconium (Zr) compound selected from At least 1 type is a chloride, The said organic solvent is the manufacturing method of the metal mixed oxide electrode characterized by the above-mentioned. The method of claim 5, wherein the heat treatment in step (c2) is performed for 10 to 30 minutes at 400 to 700 ° C in an oxidizing atmosphere. The method of claim 5, wherein the final heat treatment of step (d) is performed for 3 to 6 hours at a temperature of 400 to 700 ° C in an oxidizing atmosphere.