KR100487677B1 - An insoluble electrode on which a platinum contained oxide covering is formed and its manufacturing method - Google Patents

Abstract

end. The technical field to which the invention described in the claims belongs.

       The present invention relates to an insoluble electrode having a platinum group-based oxide coating layer applied to wastewater treatment, and a method of manufacturing the same. Particularly, it is possible to improve durability and reactivity while reducing manufacturing cost by reducing the content of expensive platinum group metals. will be.

       I. The technical problem to be solved by the invention.

Currently, electrodes formed with platinum group oxide coating layers among the electrodes used for electrolysis show excellent performance in durability and reactivity, and thus can be usefully applied to various industrial fields such as plating process as well as difficult degradable wastewater treatment. As a constituent of the coating material, expensive platinum group-based precious metals occupy most of them and require huge manufacturing costs, so they are applied to only a few parts of the field.

Therefore, a method of providing a platinum group-based electrode at a low manufacturing cost by reducing the content of the platinum group metal and increasing the content of other metals as a constituent of the coating material has been attempted. It will be embraced.

All. Summary of the Solution of the Invention.

       In general, among the platinum group metals mainly used for forming the platinum group coating layer, the metals of the platinum group having the same iridium (Ir) have the highest oxidation power and have a wide range of current voltage control and the electroplating method is free to control the coating thickness. Focusing on forming the first iridium (Ir) coating layer of the thin film through the electroplating process, and then the secondary coating layer having a normal thickness through the thermal deposition process using a multi-component metal oxide containing platinum group metals on its surface It is to form an electrode to improve the durability and reactivity with a double layer oxide coating layer while reducing the content of the platinum group metals as a whole to form.

       la. Important use of the invention.

       For electrolysis.

Description

       An insoluble electrode on which a platinum contained oxide covering is formed and its manufacturing method}

The present invention relates to an insoluble electrode having a platinum group-based oxide coating layer applied to wastewater treatment, and a method of manufacturing the same. In particular, the first thin film coating layer of pure platinum group metal through an electroplating process and a platinum group-based multi-layer through a thermal deposition process. The secondary coating layer of the component metal oxide is to improve the durability and reactivity while reducing the content of expensive platinum group metal.

A known electrode manufacturing technique used for electrolysis in the past has formed a coating layer using carbonitride using arc melting or plasma melting using titanium as an electrode body, and the process is quite complicated and dangerous. It is not easy to apply practically, and there is not only a large loss of coating material for forming the coating layer, but also the coating layer is easily peeled off, and the durability is weak, and it is difficult to use for a long time due to the deterioration of life due to high energy consumption. There was this.

Therefore, in recent years, the electrolytic voltage can be lowered, the current consumption is low, the adhesion to the electrode body is excellent, the durability is excellent, and the platinum group metals have the characteristics of improving the reactivity due to the excellent elution of hydrogen-oxygen generation from the electrode. As a coating material, various methods for producing an electrode having a platinum group oxide coating layer which can be usefully applied to various industrial fields such as plating as well as difficult degradable wastewater treatment have been attempted, but are expensive as a constituent of the coating material. Only a few precious metals of the platinum group series are required for huge manufacturing costs.

Therefore, a method of providing a platinum group-based electrode at a low manufacturing cost by reducing the content of the platinum group metal and increasing the content of other metals as a constituent of the coating material has been attempted, but this leads to a decrease in durability and reactivity. You have a problem.

      Therefore, the present invention has been made to solve the above-mentioned conventional problems, an object of the present invention is to provide an insoluble electrode formed of a platinum group-based oxide coating layer that can improve the durability and reactivity than the electrode manufactured at a low production cost To make it.

To this end, first, by using iridium (Ir) on the surface of the electrode body to form a primary thin film coating layer of iridium (Ir), a pure platinum group metal through an electroplating process, platinum (Pt), iridium (Ir), ruthenium A secondary coating layer of a platinum group-based multicomponent metal oxide composed of (Ru) platinum group metals, tin (Sn) and non-platinum group metals of titanium dioxide (TiO ₂ ) is formed through a repeated thermal deposition process.

       Hereinafter, the present invention will be described in detail with reference to the following examples.

       First, the present invention is a known electrode manufacturing method for producing an insoluble anode by forming a platinum group-based oxide coating layer through a thermal deposition process, the electroplating process using iridium (Ir) prior to the thermal deposition process Forming a thin iridium (Ir) primary coating layer.

       At this time, the reason for the electroplating of iridium (Ir) in the present invention is a metal having the highest oxidation power among the same platinum group metals of iridium (Ir), the control range of the current voltage is wide, the thickness of the coating layer can be freely adjusted through the electroplating method This is because the thin film layer can be formed.

       To this end, the iridium (Ir) electroplating process carried out in the present invention,

① dissolving 0.22 mM-1 mM K ₃ IrCl ₆ (Potassium iridium chloride) in 1 mM-5 mM oxalic acid,

       ② pH control step (pH: 9 ~ 11),

       (3) stabilizing by leaving it at room temperature;

⑤ It consists of plating step at applied voltage 0.1 ~ 1.0V, current density 0.01 ~ 0.05mA / cm ² .

       Electroplating process of iridium (Ir) according to another embodiment

① 10 ~ 50mMNa ₂ IrCl ₆ 6H ₂ O in 0.1M hydrogen chloride (HCl) (10ml) and ethanol

dissolving sodium iridium chloride,

       ② heating to 70 ° C.,

       ③ adding ethanol to maintain the solution volume;

       ④ pH adjustment step,

       ⑤ the second heating step to check the color change,

       ⑥ to stabilize at room temperature,

⑦ applied voltage: 0.1 ~ 1.0V, the current density of 0.01 ~ 0.05mA / cm ² consists of a step of plating.

       At this time, the reason why the applied voltage is 0.1 ~ 1.0V in the electroplating process is because the coating layer is too thin when the applied voltage is less than 0.1V, and when the applied voltage is above 1.0V, the coating layer becomes thick and the strength becomes uneven, but the coating layer is uneven. This is because it is not possible to obtain a uniform reaction on the entire surface of the electrode surface, and the range of current density, pH control, and stabilization are common steps in a conventional electrolysis process.

       Meanwhile, titanium, nickel, carbon steel, iron, and the like are used as the material of the electrode body used for manufacturing the electrode of the present invention, and the material used is in the form of a plate, a mesh, and a rod. .

In addition, as the coating material for forming the platinum group-based oxide coating layer, three or more of complex oxides of platinum (Pt), tin (Sn), iridium (Ir), ruthenium (Ru), and metal oxides of titanium dioxide (TiO ₂ ) This mixture is used and its composition is ruthenium (Ru)-platinum (Pt)-tin (Sn), iridium (Ir)-platinum (Pt)-tin (Sn), ruthenium (Ru)-iridium (Ir) ) -Pt (Pt) -tin (Sn), ruthenium (Ru) -platinum (Pt) -titanium dioxide (TiO ₂ ), iridium (Ir) -platinum (Pt) -titanium dioxide (TiO ₂ ), ruthenium (Ru) Iridium: platinum (Pt)-tin (Sn)-titanium dioxide (TiO ₂ ), iridium (Ir)-platinum (Pt)-tin (Sn)-titanium dioxide (TiO ₂ ); (Ir) and platinum (Pt) should be 30% or less based on 100% of all components, and the other components should be 70% of composition ratio.

       In addition, the composition ratio of the coating material suggests the optimum conditions for achieving the object of the present invention, and does not limit the present invention, which merely means that the composition ratio can produce the most economical and high quality electrode. will be.

       That is, when iridium (Ir) and platinum (Pt) are less than 30%, the content of the platinum group metal is small, so durability and reactivity are slightly lowered, and when it is 30% or more, the economic efficiency is slightly lowered.

       Therefore, the object of this invention can fully be achieved even in the conditions within +/- 20% of this composition ratio range.

       In addition, the electrode of the present invention can obtain the electrode of the best performance when manufactured by the following manufacturing process, the manufacturing process is as follows,

       (1) The electrode body was polished with sand blaster and heated for 30 minutes in 10% oxalic acid to completely remove the organic oxide film on the surface of the electrode body.

       (2) Iridium (Ir) electroplating is carried out using the electroplating method presented above.

       (3) During the process of (2), dilute hydrochloric acid or isopropyl alcohol solution or a solution of hydrochloric acid and isopropyl alcohol mixed in a constant ratio is prepared as a solvent, and the coating component is dissolved in the composition of a certain ratio.

       (4) A metal oxide coating layer is formed second by applying a coating solution in which a coating component is dissolved to an electrode body to which iridium (Ir) is first electroplated by the process of (2) and repeating thermal deposition at 500 to 600 ° C. It is to prepare the electrode.

       In this case, the number of times of repeated thermal evaporation is preferably about 4 to 6 times. In this case, the required calcination temperature of 500 to 600 ° C. is a specific temperature required to pyrolyze the metal oxide to form an oxide layer having a thickness of several microns. The layer usually exhibits specific cracking due to thermal shock, which increases the active surface area of the electrode.

      However, at other temperatures other than 500 ° C or above 600 ° C, this particular temperature is necessary because no cracking occurs or the cracks are not clear and the effect is canceled. This cracking is required for the wastewater treatment using the actual electrode. It remains without any large deposits after application.

      Hereinafter, the present invention will be described in more detail with reference to the manufacturing examples of the electrode according to the above-described manufacturing process.

      Example 1

      (1) electrode body preparation step

         The electrode body prepared in any size is polished using a sand blaster, which is a polishing tool, degreased at about 80 ° C. in 10% oxalic acid for about 10 minutes, and washed and dried.

      (2) electroplating step

         Iridium (Ir) electroplating is performed on the prepared electrode body using the manufacturing method shown above.

      (3) Coating material liquid preparation step

         Dilute hydrochloric acid or isopropyl alcohol solution or hydrochloric acid and isopropyl alcohol in constant ratio using Ir + Pt (30%-1: 2) and Ru + Sn (70%-2: 5) Dissolve for 2 to 5 hours while stirring in the mixed solvent.

      (4) The coating material solution of (3) is brushed or supported on the electrode prepared in (2), dried for 5 minutes, and then calcined at 500 to 600 ° C to form a coating layer by thermal evaporation.

          The frequency | count at this time is performed about 4-6 times.

      (5) Performance analysis step of the electrode manufactured through the above step: by confirming the result obtained by applying to the actual wastewater and through the SEM (scanning electron microscope) to check the state of the electrode as shown in the attached photo.

Fig. Photo of electrode surface at 500-600 ℃

       Example 2

The preparation of the coating material was carried out in the same manner as in [Example 1], except that the coating material contained in [Example 2] 30% platinum (Pt), ruthenium (Ru) + tin (Sn), and [Example 3]. ] 30% iridium (Ir) + platinum (Pt) and 70% tin (Sn), [Example 4] 30% iridium (Ir) and ruthenium (Ru) + tin (Sn) 70, [Example 5 ] 30% platinum (Pt) and 70% ruthenium (Ru) + titanium dioxide (TiO ₂ ), [Example 6] Iridium (Ir) + platinum (Pt) 30% and titanium dioxide (TiO ₂ ) 70%, In Example 7, 30% of platinum (Pt) and ruthenium (Ru) + tin (Sn) + titanium dioxide (TiO ₂ ) 70%, and in [Example 8], iridium (Ir) + platinum (Pt) 30% and The electrode of the present invention was prepared by constructing 70% of tin (Sn) + titanium dioxide (TiO ₂ ).

       Therefore, the electrode of the present invention prepared as described above is a primary iridium (Ir) coating layer (2) of the thin film through the electroplating process to the surface of the electrode body 1, as shown in Figure 1, and the thermal deposition process on the surface Through the formation of a multi-component secondary metal oxide coating layer (3) including platinum group metals through the reduction of the content of the platinum group metals as a whole, while improving the durability and reactivity as a multi-layer coating layer through the electroplating and heat deposition process. You can get it.

       The above effects can be demonstrated through the following examples, and the following examples are described to help the understanding of the present invention, and the present invention is not limited thereto.

       First, electrolytic oxidation-reduction experiments were carried out using the wastewater treated as dyeing wastewater, leachate, chemical wastewater and plating wastewater, and the results of organic matter concentration in wastewater, total nitrogen treatment, heavy metal treatment, The results of chromaticity treatment are shown in Tables 3, 4, and 5 compared with the results of conventional treatment methods.

       Figures 1, 2 and 3 show the treatment efficiency according to the change in treatment time for various wastewaters using the present invention.

table. 3 Comparison of hardly degradable organic matter treatment with conventional treatment according to various wastewater

Treatment method and efficiency (%) Biological treatment Catalytic treatment Electrocoagulation Electrolytic treatment using the present invention Plating wastewater Not applicable 70 60 90-99 Livestock Wastewater 60 80 50 70-80 Dye Wastewater 60 60 50 70-80 Chemical wastewater Not applicable at high concentrations 60 40 90-99

Drawing. 1 Removal efficiency of degradable organics of this technology in various wastewaters

table. 4 Comparison of nitrogen compound treatment with conventional treatment according to various wastewater

Treatment method and efficiency (%) Biological treatment Catalytic treatment Electrocoagulation Electrolytic treatment using the present invention Plating wastewater - - - 80-95 Livestock Wastewater 60 80 60 70-80 Dye Wastewater - - - - Chemical wastewater 50 60 40 90-99

Drawing. 2 Nitrogen compound removal efficiency of this technology

table. 5 Comparison of Heavy Metals and Color Treatments with Conventional Treatments for Various Wastewaters

Treatment method and efficiency (%) Biological treatment Catalytic treatment Electrocoagulation Electrolytic treatment using the present invention Plating wastewater -(-) 40 (70) 60 (50) > 90 (> 95) Livestock Wastewater -(40) -(60) -(50) -(> 95) Dye Wastewater -(40) -(70) -(60) -(> 95) Chemical wastewater -(40) 40 (60) 50 (50) > 90 (> 90)

 () Is the efficiency with respect to chromaticity

         Drawing. 3 Heavy Metal Removal Efficiency and Color Removal Efficiency of Electrolytic Treatment in Various Wastewaters

           The following table. 6 is the result for operating conditions according to conductivity.

      As mentioned above, this table is the basis for establishing the electrode classification and operation conditions to meet the characteristics of various wastewater. 7 classified into electrodes, current densities, and voltages used for various wastewaters.

table. 6 Operation efficiency according to conductivity

Conductivity (ms / cm) (changes with chlorine concentration) Analysis Content and Efficiency (%) COD T-N heavy metal Chromaticity ≤10 70 70 > 90 80 10 to 15 90 90 > 95 > 95 ≥15 > 90 > 90 > 95 > 95

table. 7 Classification of operating conditions and equipment according to wastewater

Operating condition and equipment classification Wastewater Treatment System Current density (A / cm ² ) Voltage (V) Used electrode Plating wastewater Wastewater treatment apparatus using the electrode of the present invention 0.01-0.10 5-8 ④⑤⑥⑦⑧ⓐ Livestock Wastewater 3-8 ④⑤⑥⑦⑧ⓑ Dye Wastewater 5-8 ④⑤⑥⑦⑧ⓑ Chemical wastewater 3-7 ①②③④⑤⑥⑦⑧ⓐ

    (electrode)

(Anode) ① Ruthenium (Ru)-Platinum (Pt)-Tin (Sn) ② Iridium (Ir)-Platinum (Pt)-Tin (Sn) ③ Ruthenium (Ru)-Iridium (Ir)-Platinum (Pt)-Tin (Sn) ④ Ruthenium (Ru)-Platinum (Pt)-Titanium dioxide (TiO ₂ ) ⑤ Iridium (Ir)-Platinum (Pt)-Titanium dioxide (TiO ₂ ) ⑥ Ruthenium (Ru)-Platinum (Pt)-Tin ( Sn)-Titanium dioxide (TiO ₂ ) ⑦ Iridium (Ir)-Platinum (Pt)-Tin (Sn)-Titanium dioxide (TiO ₂ ) ⑧ Ruthenium (Ru)-Platinum (Pt)-Iridium (Ir) (Cathode) ⓐ Electroless plating electrode (nickel, iron) ⓑ Mesh, plate or rod of iron, titanium, nickel and carbon steel

       Drawing. 4 shows the results of operating the biological treatment for a long time with the application of the present invention as the primary treatment and the secondary treatment.

       These results show that the wastewater treatment system using the electrode of the present invention can be combined with existing biological treatment systems.

It can also be seen that the life of the electrode is quite constant .

The electrode according to the present invention can be manufactured at a low manufacturing cost by reducing the amount of expensive platinum group-based precious metals, as well as by the uniform electroplating process using iridium (Ir) according to the uniformity of the coating layer and the formation of the coating layer of the multilayer. Due to the improved durability and responsiveness, much longer lifespan and wider application range than conventional electrodes can be achieved even when applied to wastewater treatment.

       1 is a cross-sectional view showing the configuration of the electrode of the present invention.

                  <Description of Main Parts of Drawing>

       1: Electrode body 2: Iridium (Ir) coating layer

       3: metal oxide coating layer containing platinum group

Claims (9)

delete In a known electrode manufacturing method for forming an insoluble anode by forming a platinum group-based oxide coating layer through a thermal lamination process, an electroplating process using iridium (Ir) is preferentially performed prior to the thermal deposition process, and thus the first thin film is formed. Forming an iridium (Ir) coating layer, wherein the electroplating includes dissolving K ₃ IrCl ₆ (Potassium iridium chloride) in oxalic acid and plating under an applied voltage of 0.1 to 1.0 V. The manufacturing method of the insoluble electrode in which the platinum group series oxide coating layer was formed. The platinum group-based oxide of claim 2, wherein the electroplating comprises dissolving Na ₂ IrCl ₆ 6H ₂ O (sodium iridium chloride) in hydrogen chloride and ethanol and plating the same under an applied voltage of 0.1 to 1.0 V. The manufacturing method of the insoluble electrode in which the coating layer was formed. The method of claim 2, wherein the coating material for forming the oxide coating layer uses a mixture of three or more of platinum (Pt), tin (Sn), iridium (Ir), ruthenium (Ru) and titanium dioxide (TiO ₂ ). Method for producing an insoluble electrode formed with a platinum group-based oxide coating layer characterized in that.         5. The method of claim 4, wherein the iridium (Ir) and the platinum (Pt) are composed of 30% ± 20% or less of the constituents of the entire coating material. delete In the formation of the primary iridium (Ir) coating layer of the film foil through the electroplating process on the surface of the electrode body, and the platinum group-based secondary oxide coating layer through the thermal evaporation process is formed on the surface of the iridium (Ir) coating layer, The oxide coating layer is an electrode having a platinum group-based oxide coating layer, characterized in that at least three of platinum (Pt), tin (Sn) iridium (Ir), ruthenium (Ru), titanium dioxide (TiO ₂ ) is mixed.        8. The electrode according to claim 7, wherein the iridium (Ir) and the platinum (Pt) are composed of 30% ± 20% or less of the total components of the oxide coating layer.        8. The electrode according to claim 7, wherein the oxide coating layer is cracked.