Composite anode, preparation method thereof and electromagnetic induction anode chlorine evolution electrolysis device

Abstract

The invention discloses a preparation method of a composite anode. The preparation method comprises the following steps: step 1, forming a ruthenium-titanium composite oxide coating on the surface of a nickel substrate through a sintering process; and 2, forming a CoOCl coating on the surface of the ruthenium-titanium composite oxide coating through an electrolytic deposition process. The invention further discloses the composite anode which is prepared through the method. The invention further discloses an electromagnetic induction anode chlorine evolution electrolysis device which comprises a magnet, a direct-current power source, an electrolytic tank, a cathode and a composite anode, electrolyte is contained in the electrolytic tank, the composite anode and the cathode are both arranged in the electrolytic tank, the direct-current power source is electrically connected with the composite anode and the cathode, and the magnet is electrically connected with the direct-current power source. And the magnet is used for providing a magnetic field for the electrolysis device. According to the invention, the electrocatalytic activity on chloride ion oxidation reaction is improved, high selectivity on chloride ions is realized, and the whole chlorine evolution reaction is improved.

Description

Technical Field

[0001] The invention relates to the technical field of electrochemical water treatment, and in particular to a composite anode and a preparation method thereof, and an electromagnetic induction anode chlorine evolution electrolysis device. Background Art

[0002] Hypochlorous acid has strong oxidizing properties and can cause microorganisms to lose their functions. It is the most widely used bactericidal disinfectant in water treatment. At present, the production processes of sodium hypochlorite mainly include electrolysis and chlorination. The chlorination method mainly involves passing chlorine gas into a sodium hydroxide solution, and the sodium hydroxide reacts with chlorine to produce a sodium hypochlorite solution. This method is easy to achieve large-scale production in industrial production, but the process parameters, such as pH and temperature, must be strictly controlled to prevent side reactions from occurring and affecting the quality and quality of sodium hypochlorite. In addition, due to unfavorable factors such as the toxicity of chlorine gas, the difficulty in storage and transportation, and the potential risk of leakage, the chlorination method has gradually withdrawn from the water treatment market. The electrolysis method mainly involves electrolyzing Cl at the anode under the action of electric current. - , chlorine is produced, and the cathode electrolyzes water to produce hydrogen and alkali, and the chlorine and alkali react to produce hypochlorous acid. This method can produce hypochlorous acid in situ in the water body without the need for additional chemical agents. In recent years, it has become a common method for water body elimination.

[0003] The most commonly used electrode for electrolytic chlorine production is the DSA anode, which is a new type of anode with titanium as the substrate and an active coating with metal oxides such as ruthenium and iridium as the main components coated on the surface. After decades of development, the types of coated titanium anodes have continued to increase, and the performance has become better and better. However, when used as an anode material for electrolysis of seawater, its electrochemical catalytic activity and stability are still insufficient. At the same time, since the chloride ion concentration in water is generally low, a large amount of oxygen will be precipitated as a side reaction, making the oxygen-deficient solid solution structure of the metal oxide coating easily destroyed. At the same time, due to the low mass transfer and diffusion efficiency of chloride ions to the anode surface, the efficiency of DSA anode electrolysis for chlorine production is not high, and the energy consumption is high, which to a certain extent also limits its large-scale industrial application. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present invention is to provide a composite anode and a preparation method thereof, an electromagnetic induction anode chlorine evolution electrolysis device, to improve the electrocatalytic activity of the chloride ion oxidation reaction, achieve high selectivity for chloride ions, and improve the overall chlorine evolution reaction.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The present invention provides a method for preparing a composite anode, comprising the following steps:

[0007] Step 1: forming a ruthenium-titanium composite oxide coating on the surface of the nickel substrate through a sintering process;

[0008] Step 2: forming a CoOCl coating on the surface of the ruthenium-titanium composite oxide coating by an electrolytic deposition process.

[0009] Furthermore, in step one, the ruthenium-titanium composite oxide coating is formed by sintering twice.

[0010] Furthermore, the sintering process specifically includes:

[0011] Dissolving ruthenium chloride and titanium chloride in a solvent to obtain a coating liquid, wherein the concentration of ruthenium ions is 0.1 mol / L to 0.5 mol / L, and the concentration of titanium ions is 0.1 mol / L to 0.5 mol / L;

[0012] After the coating liquid is applied to the surface of the nickel substrate, it is sintered at 450-550° C. to form a ruthenium-titanium composite oxide coating.

[0013] Furthermore, in the electrolytic deposition process, the electrolyte includes the following components: 10 mmol / L to 1 mol / L of cobalt chloride and 0.5 to 2 mol / L of sodium chloride; wherein the electrolyte is acidic.

[0014] Furthermore, the parameters of the electrolytic deposition process are: electrolytic deposition time is 10min to 60min, current density is 2mA / cm 2 ~10mA / cm 2 .

[0015] A composite anode comprises a nickel substrate, a ruthenium-titanium composite oxide coating sintered on the surface of the nickel substrate, and a CoOCl coating deposited on the surface of the ruthenium-titanium composite oxide coating.

[0016] An electromagnetic induction anode chlorine electrolysis device comprises a composite anode, a cathode, a magnet, a DC power supply and an electrolytic cell, wherein the electrolytic cell contains an electrolyte, the composite anode and the cathode are both arranged in the electrolytic cell, the DC power supply is electrically connected to the composite anode and the cathode, and the magnet is used to provide a magnetic field to the electrolytic device.

[0017] Furthermore, the magnetic body is a magnet, which is a permanent magnet or an electromagnet. The direction of the magnetic field provided by the magnet is perpendicular to the direction of the electric field provided by the DC power supply, and the magnetic field strength is 0.1-2.0T.

[0018] Furthermore, the electrolyte is a liquid containing chloride ions, and the concentration of the chloride ions is 10 mmol / L to 2 mol / L.

[0019] Furthermore, a diaphragm is provided in the electrolytic cell, and the diaphragm divides the electrolytic cell into two reaction chambers, and the composite anode and the cathode are respectively arranged in the two reaction chambers.

[0020] The invention has the beneficial effects that: a ruthenium-titanium composite oxide coating is formed on the surface of a nickel substrate by a sintering process, and a CoOCl coating is formed by an electrolytic deposition process. The introduction of the cobalt-based composite layer enhances the catalytic activity of the anode, significantly improves the selectivity and adsorption capacity of chloride ions, enables the chlorine evolution reaction to proceed smoothly at a lower overpotential, promotes the efficient conversion of chloride ions into active chlorine and chlorine element, and thus makes it easier to effectively remove chlorine from water. Moreover, CoOCl has a magnetic induction characteristic. By introducing a magnetic field, it can drive ions near the electrode surface to perform vortex motion, and improve its mass transfer and diffusion efficiency under the action of the Lorentz force, thereby achieving directional control of the flow direction, thereby effectively compressing the thickness of the liquid film on the electrode surface, and enhancing the mass transfer and diffusion efficiency of chloride ions to the electrode surface. At the same time, the electron transfer rate on the anode surface is enhanced, thereby achieving an overall improvement in the chlorine evolution reaction. In the CoOCl catalyst, the doping of chloride ions can effectively inhibit the oxygen evolution reaction, which is more conducive to the occurrence of the chlorine evolution reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is a schematic structural diagram of an electrolysis device according to Example 1 of the present invention;

[0023] Figure 2 This is a schematic structural diagram of an electrolysis device according to Embodiment 2 of the present invention;

[0024] Figure 3 Schematic diagram of the anode surface reaction in Example 1 of the present invention;

[0025] Figure 4 This is a schematic diagram showing the variation trend of the content of chlorine element obtained during the reaction in Example 1 of the present invention;

[0026] Figure 5 Schematic diagram of the relationship between the presence or absence of a magnetic field and the chloride ion removal efficiency in Example 2 of the present invention;

[0027] Figure 6 Schematic diagram of the relationship between magnetic field strength and chloride ion removal efficiency in Example 2 of the present invention;

[0028] Figure 7 Schematic diagram of five cycle experiments in Example 2 of the present invention.

[0029] In the figure: 1. composite anode; 2. cathode; 3. magnet; 4. fixed bracket; 5. DC power supply; 6. electrolytic cell; 61. anode chamber; 62. cathode chamber; 7. diaphragm. DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the description of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In the description of the present invention, unless otherwise clearly specified and limited, the terms "set", "install", "connection" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] The directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front”, “back”, “top”, “bottom”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of description and simplified description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0033] The terms "first", "second", "third" and the like are merely used to distinguish elements of similar nature, and do not indicate or imply relative importance or a particular order.

[0034] The terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of the elements listed and may also include additional elements not expressly listed.

[0035] The present invention provides a method for preparing a composite anode, comprising the following steps:

[0036] Step 1: forming a ruthenium-titanium composite oxide coating on the surface of the nickel substrate through a sintering process;

[0037] Step 2: forming a CoOCl coating on the surface of the ruthenium-titanium composite oxide coating by an electrolytic deposition process.

[0038] Specifically, a ruthenium-titanium composite oxide coating is formed on the surface of the nickel substrate by a sintering process, and a CoOCl coating is formed by an electrolytic deposition process. The introduction of the cobalt-based composite layer enhances the catalytic activity of the anode, significantly improves the selectivity and adsorption capacity of chloride ions, enables the chlorine evolution reaction to proceed smoothly at a lower overpotential, and promotes the efficient conversion of chloride ions into active chlorine and chlorine element, thereby making it easier to effectively remove chlorine from water bodies; and CoOCl has magnetic induction characteristics. By introducing a magnetic field, it can drive the ions near the electrode surface to vortex motion, and improve its mass transfer and diffusion efficiency under the action of the Lorentz force, thereby achieving directional control of the flow direction, thereby effectively compressing the thickness of the liquid film on the electrode surface, and enhancing the mass transfer and diffusion efficiency of chloride ions to the electrode surface; at the same time, the electron transfer rate on the anode surface is enhanced, thereby achieving an overall improvement in the chlorine evolution reaction; and in the CoOCl catalyst, the doping of chloride ions can effectively inhibit the oxygen evolution reaction, which is more conducive to the occurrence of the chlorine evolution reaction. Among them, the substrate of the composite anode 1 can select a highly magnetic nickel plate or a mesh nickel electrode, and nickel has high magnetism, high conductivity and good corrosion resistance.

[0039] Furthermore, in step 1, the ruthenium-titanium composite oxide coating is formed by sintering twice, and the double sintering can significantly improve the density and strength of the ruthenium-titanium composite oxide coating.

[0040] Furthermore, the sintering process specifically includes:

[0041] The coating liquid is obtained by dissolving ruthenium chloride and titanium chloride in a solvent, wherein the concentration of ruthenium ions is 0.1 mol / L to 0.5 mol / L, and the concentration of titanium ions is 0.1 mol / L to 0.5 mol / L; the solvent can be isopropanol;

[0042] After the coating liquid is applied to the surface of the nickel substrate, it is sintered at 450-550° C. to form a ruthenium-titanium composite oxide coating, and the sintering can be performed in a muffle furnace.

[0043] Furthermore, in the electrolytic deposition process, the electrolyte includes the following components: 10 mmol / L to 1 mol / L of cobalt chloride and 0.5 to 2 mol / L of sodium chloride; wherein the electrolyte is acidic, and the pH value of the electrolyte can be adjusted to about 2 (pH = 2 ± 0.5) by sulfuric acid.

[0044] Furthermore, the parameters of the electrolytic deposition process are: electrolytic deposition time is 10min to 60min, current density is 2mA / cm 2 ~10mA / cm 2 .

[0045] like Figure 3As shown, the present invention also provides a composite anode 1, comprising a nickel substrate, a ruthenium-titanium composite oxide coating sintered on the surface of the nickel substrate, and a CoOCl coating deposited on the surface of the ruthenium-titanium composite oxide coating. The ruthenium-titanium composite oxide coating and the CoOCl coating are sequentially located on the surface of the nickel substrate, and the ruthenium-titanium composite oxide coating is located between the nickel substrate and the CoOCl coating, which is equivalent to an intermediate layer; the CoOCl coating is located in the outermost layer, and the high magnetic properties and high selectivity for chloride ions of the CoOCl composite anode material are utilized to achieve selective oxidation of chloride ions, thereby enhancing the electrocatalytic activity of the electrode for chloride ion oxidation reaction; the ruthenium-titanium composite oxide coating also has a high catalytic selectivity for chloride ions, can significantly reduce the chlorine evolution potential, increase the oxygen evolution potential, reduce the amount of oxygen precipitation, and is conducive to extending the service life of the electrode.

[0046] The present invention also provides an electromagnetic induction anode chlorine electrolysis device, such as Figure 1 As shown, it includes a composite anode 1, a cathode 2, a magnet, a DC power supply 5 and an electrolytic cell 6, wherein the electrolytic cell 6 contains an electrolyte, the composite anode 1 and the cathode 2 are both arranged in the electrolytic cell 6, the DC power supply 5 is electrically connected to the composite anode 1 and the cathode 2, and the magnet is used to provide a magnetic field to the electrolytic device. Specifically, the electrolytic cell 6 is used to provide a reaction chamber, the reaction chamber contains an electrolyte, a cathode 2 and a composite anode 1, the cathode 2 and the composite anode 1 are arranged at intervals and are both in contact with the electrolyte, the composite anode 1 with electromagnetic induction characteristics is used for electrolysis of seawater to produce chlorine or electrolysis of drinking water to produce chlorine for disinfection, the cathode 2 is used for hydrogen ion reduction, and the DC power supply 5 is used to provide current and voltage. In this device, CoOCl with magnetic induction characteristics and ruthenium titanium composite oxide are used as anode catalytic coatings, and a magnetic field is introduced. The applied magnetic field can drive the ions near the electrode surface to perform vortex motion, and improve their mass transfer and diffusion efficiency under the action of the Lorentz force, thereby realizing directional control of the flow direction, thereby effectively compressing the thickness of the liquid film on the electrode surface and enhancing the mass transfer and diffusion efficiency of chloride ions to the electrode surface. At the same time, the electron transfer rate on the anode surface is enhanced, thereby achieving an overall improvement in the chlorine evolution reaction. Furthermore, in the CoOCl catalyst, the doping of chloride ions can effectively inhibit the oxygen evolution reaction, reduce energy waste, thereby improving the current efficiency, allowing more current to be used for the chlorine evolution reaction, thereby improving the overall electrolysis efficiency, extending the electrode life, reducing by-product generation, and improving the stability of the electrolytic cell 6. Among them, a highly magnetic cathode 2 is prepared with a plate or mesh configuration such as nickel and stainless steel; preferably, the anode and cathode 2 are both nickel plates or nickel meshes as substrates to prepare highly magnetic electrodes.

[0047] Furthermore, the magnet is a magnet 3, which is a permanent magnet or an electromagnet, and the direction of the magnetic field provided by the magnet 3 is perpendicular to the direction of the electric field provided by the DC power supply 5, and the magnetic field strength is 0.1 to 2.0 T. Among them, in the field of electromagnetic reactions, from the charge transfer mechanism at the microscopic level to the macroscopic interaction between electromagnetic fields and substances, electromagnetic induction plays a fine and efficient regulatory function in many electrochemical reaction processes. In a specific electrolytic system, the precise application of an appropriate electromagnetic field can significantly change the migration rate and spatial distribution of ions, optimize the local electric field and concentration gradient on the electrode surface, and thus create a more favorable reaction environment, promote the efficient conduct of the reaction and significantly improve the generation rate and quality of the product. In addition, under the action of the magnetic field, the electron transport performance of the electrode with magnetic induction characteristics will be significantly improved, thereby enhancing the electrode reaction efficiency.

[0048] Furthermore, if Figure 1 As shown, two magnets 3 of the same size are arranged between the composite anode 1 and the cathode 2 as an external magnetic field. Among them, a fixed bracket 4 (made of acrylic material) is arranged outside the electrolytic cell 6, a magnet 3 is placed at the bottom of the fixed bracket 4, and a magnet 3 is placed on the top of the fixed bracket 4. Two magnets 3 of different sizes are placed on the outside of the electrolytic cell 6, and an external magnetic field is introduced. The applied magnetic field can drive the ions near the electrode surface to perform vortex motion, and improve its mass transfer and diffusion efficiency under the action of the Lorentz force, thereby achieving directional control of the flow direction, thereby effectively compressing the thickness of the liquid film on the electrode surface and enhancing the mass transfer and diffusion efficiency of chloride ions to the electrode surface. At the same time, the electron transfer rate on the anode surface is enhanced, thereby achieving an overall improvement in the chlorine evolution reaction.

[0049] Furthermore, the electrolyte is a liquid containing chloride ions, and the concentration of chloride ions is 10 mmol / L to 2 mol / L.

[0050] Furthermore, if Figure 2 As shown, a diaphragm 7 is also provided in the electrolytic cell 6, and the diaphragm 7 divides the electrolytic cell 6 into two reaction chambers, and the composite anode 1 and the cathode 2 are respectively arranged in the two reaction chambers. Among them, the two reaction chambers are the anode chamber 61 and the cathode chamber 62, respectively, the composite anode 1 is installed in the anode chamber 61, and the cathode 2 is installed in the cathode chamber 62. The electrolysis device has a simple structure, and the composite anode 1 and the cathode 2 can be directly placed in accordance with the traditional single electrolysis chamber, or the cathode and cathode can be separated into chambers by the diaphragm 7 to achieve acid-base separation, and placed according to the actual size of the electrolytic cell 6 or the electrode area or volume required for electrolysis.

[0051] Working principle of electromagnetic induction anode chlorine electrolysis device:

[0052] During the electrolytic chlorine reaction, Cl2 (such as Figure 3As shown), an electromagnetic field or permanent magnetic field perpendicular to the electric field direction is applied to the outside of the electrolysis system. By applying a magnetic field, the ions near the electrode surface are driven to perform vortex motion, and the mass transfer and diffusion efficiency is improved under the action of the Lorentz force, thereby effectively compressing the thickness of the liquid film on the electrode surface, enhancing the mass transfer and diffusion efficiency of chloride ions to the electrode surface, and realizing the migration of the solution through the action of the electric field force, while solving the problem of low selectivity of the chlorine evolution reaction of the existing chlorine evolution electrode. The specific chemical (ionic equations of the cathode and anode reactions are:

[0053] 2Cl - -2e - →Cl2↑

[0054] Cl - -e - →Cl ·

[0055] 2H2O+2e - →H2↑+2OH -

[0056] 2NaCl+2H2O→2NaOH+H2↑+Cl2↑

[0057] Cl · +Cl - →Cl2 ·-

[0058] Cl2 ·- +Cl2 ·- →Cl2+2Cl -

[0059] The present invention utilizes the high magnetism and high selectivity of the CoOCl composite anode 1 material to achieve selective oxidation of chloride ions, and realizes efficient chlorine evolution reaction through the synergistic effect of the electric field and the magnetic field. The electromagnetic induction anode chlorine evolution electrolysis device can be applied to the scenes of seawater electrolysis chlorine production, drinking water electrolysis chlorine production disinfection, etc., without generating secondary pollution, and can significantly reduce the electrode usage area.

[0060] Example 1

[0061] like Figure 1 As shown, the present application provides an electromagnetic induction anode chlorine evolution single-chamber electrolysis device, wherein an electrolytic cell 6 is prepared, a composite anode 1 with a high magnetic nickel plate as a substrate and a catalytic coating of CoOCl and ruthenium titanium composite oxide as an anode, a nickel plate as a cathode 2, and two magnets 3 of the same size are placed up and down outside the electrolytic cell 6 to provide a magnetic field perpendicular to the electric field direction. An electrolyte containing a certain concentration of chloride ions is injected into the electrolytic cell 6, and a certain voltage is applied to perform an electrolytic chlorine evolution reaction.

[0062] in,

[0063] The distance between the anode and cathode 2 is 5-10 cm;

[0064] There is no diaphragm 7 in the reaction chamber, forming a single-chamber electrolysis device;

[0065] The reaction current density is 5 mA / cm 2 ~15mA / cm 2 ;

[0066] The magnetic field strength is 0.1~2.0T;

[0067] The chloride ion concentration in the electrolyte is 10mmol / L~2mol / L, Cl — When the concentration is too high, the material can still oxidize chloride ions, but the effects of corrosiveness and other factors need to be considered.

[0068] Among them, the electrode has a great influence on the electrochemical system of the present invention. Different materials have a great influence on the effect of chlorine evolution reaction. In order to achieve better treatment effect, a high magnetic anode with metal nickel as the base nickel plate, ruthenium titanium composite oxide as the middle layer, and CoOCl as the catalyst is prepared as follows:

[0069] Prepare the coating liquid: the intermediate coating liquid is ruthenium chloride and titanium chloride, the solvent is isopropanol, and the concentration of the two metals is 0.1mol / L to 0.5mol / L;

[0070] Preparation of electrolyte: In the electrolytic deposition process, the electrolyte is a cobalt chloride acid solution, the cobalt chloride concentration is 10mmol / L~1mol / L, the sodium chloride concentration is 0.5~2mol / L, and the pH value of the electrolyte is adjusted to about 2 by sulfuric acid;

[0071] Forming coating:

[0072] a. After applying the coating liquid to the surface of the nickel substrate, sintering at 450-550° C. to form a ruthenium-titanium composite oxide coating;

[0073] b. In the electrolytic deposition process, the electrodeposition time is 10min to 60min, and the current density is 2mA / cm 2 ~10mA / cm 2 .

[0074] The ruthenium-titanium composite oxide coating is formed on the surface of the nickel substrate through two thermal sintering steps, and the CoOCl coating is formed on the surface of the ruthenium-titanium composite oxide coating through one electrolytic deposition step.

[0075] In this electrolysis device, the chloride ion concentration in the electrolyte is 10mmol / L. During the electrolysis process, Figure 3 is a schematic diagram of the surface reaction of the composite anode 1. By measuring the concentration of chlorine element changing with time, the following is obtained: Figure 4 The chlorine element concentration-reaction time diagram is shown.

[0076] Through analysis, we can know that Figure 4 As shown, due to the action of the Lenz force, the water flow without any flow presents an eddy current state as the power is turned on, which improves its mass transfer efficiency and also increases the total amount of chlorine. Because of its fluidity, the chlorine production will not gradually slow down in the absence of a magnetic field.

[0077] The reactions on the cathode and anode surfaces are as follows:

[0078] 2Cl - -2e - →Cl2↑

[0079] Cl - -e - →Cl ·

[0080] 2H2O+2e - →H2↑+2OH -

[0081] 2NaCl+2H2O→2NaOH+H2↑+Cl2↑

[0082] Cl · +Cl - →Cl2 ·-

[0083] Cl2 ·- +Cl2 ·- →Cl2+2Cl -

[0084] like Figure 4 As shown, in this embodiment, the chloride ion concentration in water is 10mmol / L, and the concentration of the obtained chlorine element does not change greatly over time. Moreover, as the magnet 3 causes the water to flow, the chlorine element produced by the chlorine evolution reaction does not tend to decrease as the reaction proceeds. On the contrary, as the reaction proceeds, the output of the chlorine element shows a trend of first increasing and then decreasing.

[0085] The anode of the present invention uses a metal nickel plate as a substrate and uses CoOCl and ruthenium-titanium composite oxide as a catalytic coating. The introduction of the cobalt-based composite intermediate layer greatly enhances the catalytic activity of the anode, significantly improves the selectivity and adsorption capacity of chloride ions, enables the chlorine evolution reaction to proceed smoothly at a lower overpotential, and promotes the efficient conversion of chloride ions into active chlorine (Cl · 、Cl2 ·- ) and chlorine, making it easier to effectively remove chlorine from water bodies.

[0086] In the electromagnetic induction system of the present invention, the external magnetic field plays an important role. The presence of the magnetic field can drive the ions near the electrode surface to perform vortex motion, thereby improving the mass transfer and diffusion efficiency of chloride ions to the electrode surface. At the same time, the magnetic field also optimizes the local electric field and concentration gradient on the electrode surface, compresses the thickness of the liquid film on the electrode surface, further improves the chlorine evolution effect, and provides strong support for efficient electrocatalytic chlorine evolution reaction. The synergistic effect of the electric field and the magnetic field provides favorable conditions for efficient chlorine evolution reaction, improves the reaction performance, and can significantly reduce the electrode usage area.

[0087] Example 2

[0088] like Figure 2 As shown, the present application provides an electromagnetic induction anode chlorine evolution chamber electrolysis device, and the difference between the device of Example 2 and Example 1 is that: Example 2 divides the electrolytic cell 6 into two reaction chambers, namely the anode chamber 61 and the cathode chamber 62, by a diaphragm 7. And the manufacturing method of the composite anode 1 in Example 2 is the same as the manufacturing method of the composite anode 1 in Example 1.

[0089] The experimental conditions are as follows: the initial chloride ion concentration is 10 mmol·L -1 200mL of electrolyte was used as simulated wastewater, the size of the cathode and anode was 5cm×10cm. The ambient temperature was 25±0.5℃, the pH of the electrolyte was adjusted to 2 by sulfuric acid, and the effective volume of the reactor was 125cm 3 The cathode and anode chambers are separated by a diaphragm 7. A DC regulated power supply provides 10 mA / cm 2 Current is applied, and magnets with the same magnetic properties are placed at the upper and lower ends respectively. The reaction time is 150 minutes.

[0090] The following experiments were performed using the continuous reaction mode:

[0091] (1) In the electrolysis device, an experiment was conducted to determine the effect of the presence or absence of a magnetic field on the efficiency of chloride ion removal:

[0092] Specifically, the experimental results are as follows Figure 5 As shown, the results show that after 150 min of reaction and 1 mA / cm 2 Under the current density of , under the action of the magnetic field, the chloride ion concentration in the effluent is effectively reduced to below 1mmol / L; through measurement, regardless of whether the magnetic field is provided, the pH on the surface of the system electrode does not change much as the reaction proceeds. Experiments have shown that the CoOCl composite anode 1 in the system of the present invention can have a high selectivity for chloride ions and is conducive to the chlorine evolution reaction. With the introduction of the magnetic field, this efficient chlorine evolution reaction becomes faster, and the thickness of the liquid film on the electrode surface is thinner, further enhancing the chlorine evolution effect, and providing strong support for the efficient electrocatalytic chlorine evolution reaction.

[0093] (2) In this electrolysis device, an experiment was conducted to examine the effect of changing the strength of the magnetic field on the efficiency of chloride ion removal:

[0094] Specifically, the experimental results are as follows Figure 6 As shown, at a current density of 10 mA / cm 2 Under the condition of constant current, the influence of different magnetic conditions on the chlorine evolution reaction was explored. A continuous reaction experiment was carried out, with each group of reactions lasting 150 minutes. The magnetic force of magnet 3 was 0.5 and 1.0 T respectively. The chlorine evolution reaction was carried out under each magnetic field strength, and the changes of various indicators during the reaction were observed and recorded. The results show that with the increase of the magnetic force of magnet 3, the electrocatalytic chlorine evolution reaction is more thorough, and the chloride ion concentration in the effluent water drops to below 1mmol / L.

[0095] (3) In the electrolysis device, an electrolysis device stability test is carried out:

[0096] In order to more comprehensively evaluate the performance of the electrolysis system, multiple cycle tests will be carried out. Figure 7 As shown. After each cycle, carefully observe the changes in the morphology, roughness, element distribution, etc. of the electrode surface to analyze whether there are deposits, corrosion, or structural damage. At the same time, compare and analyze the key indicator data of each cycle to determine the stability and reliability of the electrolysis system in long-term operation. Figure 7 As shown, after five cycles of reaction experiments, there was no obvious corrosion on the CoOCl composite anode 1, and there was no significant change in the removal efficiency of chloride ions.

[0097] Through the above comprehensive and detailed experimental design and index determination, we can gain an in-depth understanding of the performance characteristics of the electromagnetic induction anode chlorine electrolysis device and provide a strong scientific basis for its optimization and practical application.

[0098] The present invention fundamentally and deeply optimizes the kinetics and thermodynamics of the chlorine evolution reaction, achieves a breakthrough improvement in the efficiency and performance of the chlorine evolution reaction by preparing a high chlorine evolution reaction electrode and applying an external magnetic field, and provides a new method and new idea for the design of an electrochlorination system for efficient sterilization and disinfection of low-chlorine water bodies.

[0099] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this profession can make some changes or modifications to the technical contents disclosed above without departing from the scope of the technical solution of the present invention, which are equivalent embodiments of equivalent changes. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a composite anode, characterized in that: The following steps are involved: Step 1: forming a ruthenium-titanium composite oxide coating on the surface of the nickel substrate through a sintering process; Step 2: forming a CoOCl coating on the surface of the ruthenium-titanium composite oxide coating by an electrolytic deposition process.

2. The method for preparing a composite anode according to claim 1, characterized in that: In step one, the ruthenium-titanium composite oxide coating is formed by sintering twice.

3. The method for preparing a composite anode according to claim 1, characterized in that: The sintering process specifically includes: Dissolving ruthenium chloride and titanium chloride in a solvent to obtain a coating liquid, wherein the concentration of ruthenium ions is 0.1 mol / L to 0.5 mol / L, and the concentration of titanium ions is 0.1 mol / L to 0.5 mol / L; After the coating liquid is applied to the surface of the nickel substrate, it is sintered at 450-550° C. to form a ruthenium-titanium composite oxide coating.

4. The method for preparing a composite anode according to claim 1, characterized in that: In the electrolytic deposition process, the electrolyte includes the following components: 10 mmol / L to 1 mol / L of cobalt chloride and 0.5 to 2 mol / L of sodium chloride; wherein the electrolyte is acidic.

5. The method for preparing a composite anode according to claim 1, characterized in that: The parameters of the electrolytic deposition process are: electrolytic deposition time is 10min to 60min, current density is 2mA / cm 2 ~10mA / cm 2 .

6. A composite anode, characterized in that: The invention comprises a nickel substrate, a ruthenium-titanium composite oxide coating sintered on the surface of the nickel substrate and a CoOCl coating deposited on the surface of the ruthenium-titanium composite oxide coating.

7. An electromagnetic induction anode chlorine electrolysis device, characterized in that: The invention comprises a composite anode (1), a cathode (2), a magnet, a direct current power supply (5) and an electrolytic cell (6), wherein the electrolytic cell (6) contains an electrolyte, the composite anode (1) and the cathode (2) are both arranged in the electrolytic cell (6), the direct current power supply (5) is electrically connected to the composite anode (1) and the cathode (2), and the magnet is used to provide a magnetic field to the electrolytic device.

8. The electromagnetic induction anode chlorine electrolysis device according to claim 7, characterized in that: The magnetic body is a magnet (3), and the magnet (3) is a permanent magnet or an electromagnet. The direction of the magnetic field provided by the magnet (3) is perpendicular to the direction of the electric field provided by the DC power supply (5), and the magnetic field strength is 0.1 to 2.0 T.

9. The electromagnetic induction anode chlorine electrolysis device according to claim 7, characterized in that: The electrolyte is a liquid containing chloride ions, and the concentration of the chloride ions is 10 mmol / L to 2 mol / L.

10. The electromagnetic induction anode chlorine electrolysis device according to claim 7, characterized in that: A diaphragm (7) is also provided in the electrolytic cell (6), and the diaphragm (7) divides the electrolytic cell (6) into two reaction chambers. The composite anode (1) and the cathode (2) are respectively arranged in the two reaction chambers.

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