Stabilized production of high-purity low-impurity sodium hypochlorite

Abstract

The application discloses a stable preparation method of high-purity low-impurity sodium hypochlorite and belongs to the technical field of inorganic compound preparation. The preparation method comprises the following steps: a modified graphite electrode is installed on an anode, a stainless steel is used as a cathode, the distance between the cathode and the anode is 4mm-5mm, the concentration of a sodium chloride solution is adjusted to 32g / L-36g / L, the flow of the sodium chloride solution is controlled to be 3L / h-3.4L / h, the direct current voltage is set to be 5V-5.5V, the direct current is adjusted to be 52A-56A, and the power supply is turned on to prepare a sodium hypochlorite solution. The modified graphite electrode obtained by modifying the graphite anode material is installed on the anode to perform electrolysis, and a sodium hypochlorite solution with low iron ion impurity content and high effective chlorine concentration is obtained.

Description

Technical Field

[0001] This invention belongs to the field of inorganic compound preparation technology, specifically relating to a method for the stabilization preparation of high-purity, low-impurity sodium hypochlorite. Background Technology

[0002] Sodium hypochlorite is an inorganic compound with strong oxidizing properties. At room temperature, it is a pale yellow-green transparent liquid, readily soluble in water. Its aqueous solution is commonly known as bleach. It possesses highly efficient and broad-spectrum disinfection, sterilization, bleaching, and oxidation properties, and its preparation process is relatively simple and inexpensive. It is widely used in municipal water supply, medical and health care, food processing, textile and papermaking, environmental protection, and many other fields. As an important chlorine-containing disinfectant, the preparation technology of sodium hypochlorite directly determines its product concentration, purity, and application effect. Currently, the main methods for preparing sodium hypochlorite are chemical synthesis and electrolysis. Chemical synthesis primarily uses the caustic soda chlorination method (liquid alkali chlorination method), while electrolysis primarily uses the diaphragm-free electrolysis of brine. The caustic soda chlorination method is the mainstream method for large-scale industrial production of sodium hypochlorite, possessing advantages such as mature technology, high yield, high product concentration, and low cost. It is suitable for large-scale industrial production. Its core principle is the reaction of chlorine gas with sodium hydroxide solution to produce sodium hypochlorite, sodium chloride, and water. Electrolysis is mainly divided into diaphragm-free electrolysis and diaphragm electrolysis. Diaphragm-free electrolysis of brine is widely used in small and medium-sized production enterprises and on-site preparation due to its simple process, low equipment investment, and convenient operation. Its core principle is that under the action of a DC electric field, sodium and chloride ions in the brine solution undergo directional movement. Chloride ions move towards the anode, where they lose electrons to generate chlorine gas. Water molecules gain electrons at the cathode, generating hydrogen gas and hydroxide ions. The hydroxide ions combine with sodium ions to form sodium hydroxide. Because a diaphragm-free electrolytic cell is used, the chlorine gas generated at the anode cannot be separated from the sodium hydroxide generated at the cathode, and they immediately react in the solution to generate sodium hypochlorite. The core quality indicators of sodium hypochlorite are the effective chlorine concentration and impurity content. Different preparation methods have different process conditions and reaction mechanisms, which significantly affect the effective chlorine concentration and impurity content. Furthermore, within the same preparation method, changes in process parameters (such as reaction temperature, raw material ratio, and electrolysis conditions) can also lead to fluctuations in concentration and impurity content.

[0003] Electrolysis requires only high-purity salt and water, while the caustic soda chlorination method requires liquid chlorine and caustic soda. Liquid chlorine and caustic soda easily introduce iron ion metal salt impurities. Therefore, sodium hypochlorite prepared by electrolysis has a greater advantage in impurity control. However, the effective chlorine concentration of sodium hypochlorite obtained by electrolysis is greatly affected by the electrode material and is often lower than that obtained by caustic soda chlorination.

[0004] Therefore, improving the performance of electrode materials so that the sodium hypochlorite prepared by electrolysis not only has lower impurities but also increases the effective chlorine concentration has a significant promoting effect on the efficiency of sodium hypochlorite preparation by electrolysis. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention modifies the graphite anode material used in electrolysis to obtain a modified graphite electrode, which is then electrolyzed to obtain a high-purity, low-impurity sodium hypochlorite solution, thereby solving the technical problems mentioned in the background art. Specifically, the technical solution of this invention includes the following:

[0006] A method for stabilizing and preparing high-purity, low-impurity sodium hypochlorite, the method comprising the following steps:

[0007] A modified graphite electrode is installed at the anode, and a stainless steel cathode is used. The distance between the cathode and the anode is 4mm~5mm. The concentration of the sodium chloride solution is adjusted to 32g / L~36g / L, the flow rate of the sodium chloride solution is controlled to 3L / h~3.4L / h, the DC voltage is set to 5V~5.5V, and the DC current is adjusted to 52A~56A. The sodium hypochlorite solution is prepared by connecting the power supply.

[0008] Furthermore, the preparation method of the modified graphite electrode includes the following steps:

[0009] Dopamine hydrochloride, ruthenium trichloride, template agent, and aqueous hydrochloric acid solution were mixed together in a weight ratio of 2~3:0.1:20~30:80~100 to obtain a dispersion. The dispersion was adjusted to pH 8.5~9.0 and reacted at 20℃~25℃ for 20h~24h to obtain ruthenium hydroxide@PDA.

[0010] Ruthenium hydroxide@PDA was impregnated in copper chloride solution for 1-2 hours to obtain copper-doped ruthenium hydroxide@PDA. Copper-doped ruthenium hydroxide@PDA, crosslinking agent and pretreated graphite were mixed in a weight ratio of 1:0.1:3-4 and reacted at pH 10-11 for 4-5 hours. Then, the mixture was treated at 300-400℃ for 7-8 hours to obtain crosslinked graphite material.

[0011] Cross-linked graphite material, binder and solvent are mixed and ground in a weight ratio of 90~95:5~10:20~30 to obtain a slurry. The slurry is pressed at 30MPa~40MPa for 1min~2min and then vacuum dried at -0.08MPa and 80℃ for 12h to obtain the modified graphite electrode.

[0012] Furthermore, the template agent includes poloxamer 407.

[0013] Furthermore, the pH of the hydrochloric acid aqueous solution is 4.5 to 5.0.

[0014] Furthermore, the molar concentration of the copper chloride solution is 0.01 mol / L.

[0015] Furthermore, the crosslinking agent includes divinyl sulfone.

[0016] Furthermore, the method for preparing the pretreated graphite includes the following steps:

[0017] The pretreated graphite was obtained by activating graphite with plasma.

[0018] Furthermore, the graphite has a particle size of 90 μm.

[0019] Furthermore, the activation treatment conditions include a treatment power of 20W~60W, a treatment time of 3min~5min, a gas flow rate of 20mL / min, and a treatment atmosphere consisting of oxygen and argon in a volume ratio of 3:1.

[0020] Furthermore, the adhesive comprises a PVDF adhesive of type FLEX 2801.

[0021] Furthermore, the solvent is N-methylpyrrolidone.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) This invention utilizes the oxidative self-polymerization of dopamine in an alkaline environment to form an adhesive polydopamine structure. This structure has multiple active sites that can bind metal ions through coordination, thereby obtaining copper-doped ruthenium hydroxide@PDA. The synergistic effect of crosslinking of the hydroxyl groups on the pretreated graphite by the crosslinking agent and the adhesion of polydopamine improves the stability of the chemical modification of the pretreated graphite. Copper and ruthenium form crystals with oxide structures during high-temperature calcination. The ruthenium oxide has an extremely low chlorine evolution overpotential and a very strong catalytic ability for the oxidation of chloride ions, which can improve the chlorine evolution efficiency. The copper oxide structure can refine the grains and improve the catalytic stability. The two work synergistically to improve the efficiency of sodium hypochlorite preparation by electrolysis.

[0024] (2) Through the preparation method of the present invention, not only is the goal of low impurities achieved, but the available chlorine in sodium hypochlorite is also greatly increased. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Unless otherwise stated, all raw materials and reagents used in this invention are commercially available or can be prepared by known methods.

[0027] Preparation Example 1

[0028] The preparation of pretreated graphite is as follows:

[0029] Graphite particles with a diameter of 90 μm were first washed with anhydrous acetone, then rinsed with deionized water, and then dried in an 80℃ oven to remove moisture. A mixed gas source of oxygen and argon at a volume ratio of 3:1 was introduced into the plasma equipment at a flow rate of 20 mL / min, with the power adjusted to 20 W. After the equipment stabilized, the dried graphite was placed inside for plasma treatment, with a treatment time of 3 minutes.

[0030] Preparation Example 2

[0031] The preparation of pretreated graphite is as follows:

[0032] Graphite particles with a diameter of 90 μm were first washed with anhydrous acetone, then rinsed with deionized water, and then dried in an 80℃ oven to remove moisture. A mixed gas source of oxygen and argon at a volume ratio of 3:1 was introduced into the plasma equipment at a flow rate of 20 mL / min, with the power adjusted to 40 W. After the equipment stabilized, the dried graphite was placed inside for plasma treatment, with a treatment time of 4 minutes.

[0033] Preparation Example 3

[0034] The preparation of pretreated graphite is as follows:

[0035] Graphite particles with a diameter of 90 μm were first washed with anhydrous acetone, then rinsed with deionized water, and then dried in an 80℃ oven to remove moisture. A mixed gas source of oxygen and argon at a volume ratio of 3:1 was introduced into the plasma equipment at a flow rate of 20 mL / min, with the power adjusted to 60 W. After the equipment stabilized, the dried graphite was placed inside for plasma treatment, with a treatment time of 5 minutes.

[0036] Preparation Example 4 Comparative Example 1

[0037] The preparation of pretreated graphite is as follows:

[0038] Graphite particles with a diameter of 50 μm were first washed with anhydrous acetone, then rinsed with deionized water, and then dried in an 80℃ oven to remove moisture. A mixed gas source of oxygen and argon at a volume ratio of 3:1 was introduced into the plasma equipment at a flow rate of 20 mL / min, with the power adjusted to 20-60 W. After the equipment stabilized, the dried graphite was placed inside for plasma treatment, with the treatment time controlled at 3-5 minutes.

[0039] Preparation Example 5 Comparative Example 2

[0040] The preparation of pretreated graphite is as follows:

[0041] Graphite particles with a diameter of 90 μm were first washed with anhydrous acetone, then rinsed with deionized water, and then dried in an 80℃ oven to remove moisture. A mixed gas source of oxygen and argon at a volume ratio of 3:1 was introduced into the plasma equipment at a flow rate of 20 mL / min, with the power adjusted to 100 W. After the equipment stabilized, the dried graphite was placed inside for plasma treatment, with a treatment time of 10 min.

[0042] Preparation Example 6

[0043] The modified graphite electrode was prepared as follows:

[0044] Weigh 20 parts by weight of dopamine hydrochloride, 1 part by weight of ruthenium trichloride, 200 parts by weight of poloxamer 407 and 800 parts by weight of hydrochloric acid aqueous solution with pH 5.0 and mix them together until they are evenly dispersed to obtain a dispersion. Then, adjust the pH of the dispersion to 8.5 with sodium hydroxide solution, and then transfer it to 20°C and stir at 150 r / min for 20 h. After the reaction was completed, the filter cake was collected by filtration and rinsed with deionized water until the rinsing wastewater reached neutrality. Then, it was dried with anhydrous sodium sulfate to obtain ruthenium hydroxide@PDA. The obtained ruthenium hydroxide@PDA was completely immersed in a copper chloride solution with a molar concentration of 0.01 mol / L, and then treated at 25°C for 1 h. After filtration, copper-doped ruthenium hydroxide@PDA was obtained. 1 part by weight of copper-doped ruthenium hydroxide@PDA and 3 parts by weight of the pretreated graphite obtained in Preparation Example 1 were weighed and mixed in 20 parts by weight of deionized water. Then, it was dispersed in an ultrasonic power of 400 W for 15 min. The pH was then adjusted to 10 with sodium hydroxide solution. Subsequently, 0.1 parts by weight of divinyl sulfone was added and the mixture was stirred at 200 r / min at 25°C for 4 h. After the reaction, the filtered solid was first rinsed with deionized water until the rinsing wastewater reached neutrality. Then, it was placed in a graphite crucible and calcined at 300℃ for 7 hours. After natural cooling to room temperature, cross-linked graphite material was obtained. 90 parts by weight of cross-linked graphite material, 10 parts by weight of FLEX 2801 PVDF binder and 30 parts by weight of N-methylpyrrolidone were weighed, mixed and ground at 400 r / min for 30 minutes to obtain a slurry. The slurry was poured into a mold and then subjected to a pressure of 30 MPa for 1 minute. After that, it was placed in a vacuum drying oven at -0.08 MPa and heated to 80℃ for vacuum drying for 12 hours to obtain a modified graphite electrode.

[0045] Preparation Example 7

[0046] The modified graphite electrode was prepared as follows:

[0047] Weigh 25 parts by weight of dopamine hydrochloride, 1 part by weight of ruthenium trichloride, 250 parts by weight of poloxamer 407 and 900 parts by weight of hydrochloric acid aqueous solution with pH 5.0 and mix them together until they are evenly dispersed to obtain a dispersion. Then adjust the pH of the dispersion to 8.5 with sodium hydroxide solution, and then transfer it to 20°C and stir at 150 r / min for 22 h. After the reaction was completed, the filter cake was collected by filtration and rinsed with deionized water until the rinsing wastewater reached neutrality. Then, it was dried with anhydrous sodium sulfate to obtain ruthenium hydroxide@PDA. The obtained ruthenium hydroxide@PDA was completely immersed in a copper chloride solution with a molar concentration of 0.01 mol / L, and then treated at 25°C for 2 h. After filtration, copper-doped ruthenium hydroxide@PDA was obtained. 1 part by weight of copper-doped ruthenium hydroxide@PDA and 3.5 parts by weight of the pretreated graphite obtained in Preparation Example 2 were weighed and mixed in 20 parts by weight of deionized water. Then, it was dispersed in an ultrasonic power of 400 W for 15 min. The pH was then adjusted to 10 with sodium hydroxide solution. Subsequently, 0.1 parts by weight of divinyl sulfone was added and the mixture was stirred at 200 r / min at 25°C for 5 h. After the reaction, the filtered solid was first rinsed with deionized water until the rinsing wastewater reached neutrality. Then, it was placed in a graphite crucible and calcined at 350℃ for 7.5 hours. After cooling naturally to room temperature, cross-linked graphite material was obtained. 93 parts by weight of cross-linked graphite material, 7 parts by weight of FLEX 2801 PVDF binder and 25 parts by weight of N-methylpyrrolidone were weighed, mixed and ground at 400 r / min for 30 minutes to obtain a slurry. The slurry was poured into a mold and then subjected to a pressure of 35 MPa for 1 minute. After that, it was placed in a vacuum drying oven at -0.08 MPa and heated to 80℃ for vacuum drying for 12 hours to obtain a modified graphite electrode.

[0048] Preparation Example 8

[0049] The modified graphite electrode was prepared as follows:

[0050] Weigh 30 parts by weight of dopamine hydrochloride, 1 part by weight of ruthenium trichloride, 300 parts by weight of poloxamer 407 and 1000 parts by weight of hydrochloric acid aqueous solution with pH 4.5 and mix them together until they are evenly dispersed to obtain a dispersion. Then, adjust the pH of the dispersion to 9.0 with sodium hydroxide solution, and then transfer it to 25°C and stir at 150 r / min for 24 h. After the reaction was completed, the filter cake was collected by filtration and rinsed with deionized water until the rinsing wastewater reached neutrality. Then, it was dried with anhydrous sodium sulfate to obtain ruthenium hydroxide@PDA. The obtained ruthenium hydroxide@PDA was completely immersed in a copper chloride solution with a molar concentration of 0.01 mol / L, and then treated at 30°C for 2 h. After filtration, copper-doped ruthenium hydroxide@PDA was obtained. 1 part by weight of copper-doped ruthenium hydroxide@PDA and 4 parts by weight of the pretreated graphite obtained in Preparation Example 3 were weighed and mixed in 20 parts by weight of deionized water. Then, it was dispersed in an ultrasonic power of 400 W for 15 min. The pH was then adjusted to 11 with sodium hydroxide solution. Subsequently, 0.1 parts by weight of divinyl sulfone was added and the mixture was stirred at 200 r / min at 30°C for 5 h. After the reaction, the filtered solid was first rinsed with deionized water until the rinsing wastewater reached neutrality. Then, it was placed in a graphite crucible and calcined at 400℃ for 8 hours. After natural cooling to room temperature, cross-linked graphite material was obtained. 95 parts by weight of cross-linked graphite material, 5 parts by weight of FLEX 2801 PVDF binder and 20 parts by weight of N-methylpyrrolidone were weighed, mixed and ground at 400 r / min for 30 minutes to obtain a slurry. The slurry was poured into a mold and then subjected to a pressure of 40 MPa for 2 minutes. After that, it was placed in a vacuum drying oven at -0.08 MPa and heated to 80℃ for vacuum drying for 12 hours to obtain a modified graphite electrode.

[0051] Preparation Example 9

[0052] The modified graphite electrode was prepared as follows:

[0053] The pretreated graphite in Preparation Example 8 was replaced with the pretreated graphite obtained in Preparation Example 4, and the rest of the preparation process was the same as in Preparation Example 8.

[0054] Preparation Example 10

[0055] The modified graphite electrode was prepared as follows:

[0056] The pretreated graphite in Preparation Example 8 was replaced with the pretreated graphite obtained in Preparation Example 5, and the rest of the preparation process was the same as in Preparation Example 8.

[0057] Preparation Example 11

[0058] The modified graphite electrode was prepared as follows:

[0059] The pretreated graphite in Preparation Example 8 was replaced with graphite with a particle size of 90 μm, and the rest of the preparation process was the same as in Preparation Example 8.

[0060] Preparation Example 12

[0061] The modified graphite electrode was prepared as follows:

[0062] The copper chloride solution in Preparation Example 8 was replaced with a copper chloride solution with a molar concentration of 0.1 mol / L, and the rest of the preparation process was the same as in Preparation Example 8.

[0063] Example 1

[0064] The stabilization preparation method of high-purity, low-impurity sodium hypochlorite specifically includes the following processes:

[0065] The modified graphite electrode obtained in Preparation Example 6 was installed as the anode, and the cathode was made of 304 stainless steel. The distance between the cathode and the anode was 4 mm. The concentration of the sodium chloride solution was adjusted to 32 g / L, the flow rate of the sodium chloride solution was controlled at 3 L / h, the DC voltage was set to 5 V, and the DC current was adjusted to 52 A. The power was turned on to prepare the sodium hypochlorite solution. After 2 hours of electrolysis, a sample was taken and the effective chlorine concentration of the sodium hypochlorite was measured to be 10.54 g / L, and the content of iron ions was 0.008 g / L.

[0066] Example 2

[0067] The stabilization preparation method of high-purity, low-impurity sodium hypochlorite specifically includes the following processes:

[0068] The modified graphite electrode obtained in Preparation Example 7 was installed as the anode, and the cathode was made of 304 stainless steel. The distance between the cathode and the anode was 4 mm. The concentration of the sodium chloride solution was adjusted to 34 g / L, the flow rate of the sodium chloride solution was controlled at 3.2 L / h, the DC voltage was set to 5 V, and the DC current was adjusted to 54 A. The power was turned on to prepare the sodium hypochlorite solution. After 2 hours of electrolysis, a sample was taken and the effective chlorine concentration of the sodium hypochlorite was measured to be 12.07 g / L, and the content of iron ions was 0.006 g / L.

[0069] Example 3

[0070] The stabilization preparation method of high-purity, low-impurity sodium hypochlorite specifically includes the following processes:

[0071] The modified graphite electrode obtained in Preparation Example 8 was installed as the anode, and the cathode was made of 304 stainless steel. The distance between the cathode and the anode was 5 mm. The concentration of the sodium chloride solution was adjusted to 36 g / L, the flow rate of the sodium chloride solution was controlled at 3.4 L / h, the DC voltage was set to 5.5 V, and the DC current was adjusted to 56 A. The power was turned on to prepare the sodium hypochlorite solution. After 2 hours of electrolysis, a sample was taken and the effective chlorine concentration of the sodium hypochlorite was measured to be 12.23 g / L, and the content of iron ions was 0.007 g / L.

[0072] Comparative Example 1

[0073] The stabilization preparation method of high-purity, low-impurity sodium hypochlorite specifically includes the following processes:

[0074] The modified graphite electrode obtained in Preparation Example 9 was installed as the anode, and the cathode was made of 304 stainless steel. The distance between the cathode and the anode was 5 mm. The concentration of the sodium chloride solution was adjusted to 36 g / L, the flow rate of the sodium chloride solution was controlled at 3.4 L / h, the DC voltage was set to 5.5 V, and the DC current was adjusted to 56 A. The power was turned on to prepare the sodium hypochlorite solution. After electrolysis for 2 hours, a sample was taken and the effective chlorine concentration of the sodium hypochlorite was measured to be 3.92 g / L, and the content of iron ions was 0.008 g / L.

[0075] Comparative Example 2

[0076] The stabilization preparation method of high-purity, low-impurity sodium hypochlorite specifically includes the following processes:

[0077] The modified graphite electrode obtained in Preparation Example 10 was installed as the anode, and the cathode was made of 304 stainless steel. The distance between the cathode and the anode was 5 mm. The concentration of the sodium chloride solution was adjusted to 36 g / L, the flow rate of the sodium chloride solution was controlled at 3.4 L / h, the DC voltage was set to 5.5 V, and the DC current was adjusted to 56 A. The power was turned on to prepare the sodium hypochlorite solution. After 2 hours of electrolysis, a sample was taken and the effective chlorine concentration of the sodium hypochlorite was measured to be 4.85 g / L, and the content of iron ions was 0.009 g / L.

[0078] Comparative Example 3

[0079] The stabilization preparation method of high-purity, low-impurity sodium hypochlorite specifically includes the following processes:

[0080] The modified graphite electrode obtained in Preparation Example 11 was installed as the anode, and the cathode was made of 304 stainless steel. The distance between the cathode and the anode was 5 mm. The concentration of the sodium chloride solution was adjusted to 36 g / L, the flow rate of the sodium chloride solution was controlled at 3.4 L / h, the DC voltage was set to 5.5 V, and the DC current was adjusted to 56 A. The power was turned on to prepare the sodium hypochlorite solution. After 2 hours of electrolysis, a sample was taken and the effective chlorine concentration of the sodium hypochlorite was measured to be 2.57 g / L, and the content of iron ions was 0.009 g / L.

[0081] Comparative Example 4

[0082] The stabilization preparation method of high-purity, low-impurity sodium hypochlorite specifically includes the following processes:

[0083] The modified graphite electrode obtained in Preparation Example 12 was installed as the anode, and the cathode was made of 304 stainless steel. The distance between the cathode and the anode was 5 mm. The concentration of the sodium chloride solution was adjusted to 36 g / L, the flow rate of the sodium chloride solution was controlled at 3.4 L / h, the DC voltage was set to 5.5 V, and the DC current was adjusted to 56 A. The power was turned on to prepare the sodium hypochlorite solution. After 2 hours of electrolysis, a sample was taken and the effective chlorine concentration of the sodium hypochlorite was measured to be 5.06 g / L, and the content of iron ions was 0.007 g / L.

[0084] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for stabilizing and preparing high-purity, low-impurity sodium hypochlorite, characterized in that, The preparation method includes the following steps: A modified graphite electrode is installed at the anode, and a stainless steel cathode is used. The distance between the cathode and the anode is 4mm~5mm. The concentration of the sodium chloride solution is adjusted to 32g / L~36g / L, the flow rate of the sodium chloride solution is controlled to 3L / h~3.4L / h, the DC voltage is set to 5V~5.5V, and the DC current is adjusted to 52A~56A. The sodium hypochlorite solution is prepared by connecting the power supply.

2. The method for stabilizing and preparing high-purity, low-impurity sodium hypochlorite according to claim 1, characterized in that, The method for preparing the modified graphite electrode includes the following steps: Dopamine hydrochloride, ruthenium trichloride, template agent, and aqueous hydrochloric acid solution were mixed together in a weight ratio of 2~3:0.1:20~30:80~100 to obtain a dispersion. The dispersion was adjusted to pH 8.5~9.0 and reacted at 20℃~25℃ for 20h~24h to obtain ruthenium hydroxide@PDA. Ruthenium hydroxide@PDA was impregnated in copper chloride solution for 1-2 hours to obtain copper-doped ruthenium hydroxide@PDA. Copper-doped ruthenium hydroxide@PDA, crosslinking agent and pretreated graphite were mixed in a weight ratio of 1:0.1:3-4 and reacted at pH 10-11 for 4-5 hours. Then, the mixture was treated at 300-400℃ for 7-8 hours to obtain crosslinked graphite material. Cross-linked graphite material, binder and solvent are mixed and ground in a weight ratio of 90~95:5~10:20~30 to obtain a slurry. The slurry is pressed at 30MPa~40MPa for 1min~2min and then vacuum dried at -0.08MPa and 80℃ for 12h to obtain the modified graphite electrode.

3. The method for stabilizing and preparing high-purity, low-impurity sodium hypochlorite according to claim 2, characterized in that, The template agent includes poloxamer 407.

4. The method for stabilizing and preparing high-purity, low-impurity sodium hypochlorite according to claim 2, characterized in that, The molar concentration of the copper chloride solution is 0.01 mol / L.

5. The method for stabilizing and preparing high-purity, low-impurity sodium hypochlorite according to claim 2, characterized in that, The crosslinking agent includes divinyl sulfone.

6. The method for stabilizing and preparing high-purity, low-impurity sodium hypochlorite according to claim 2, characterized in that, The method for preparing the pretreated graphite includes the following steps: The pretreated graphite was obtained by activating graphite with plasma.

7. The method for stabilizing and preparing high-purity, low-impurity sodium hypochlorite according to claim 6, characterized in that, The activation treatment conditions include a treatment power of 20W~60W, a treatment time of 3min~5min, a gas flow rate of 20mL / min, and a treatment atmosphere consisting of oxygen and argon in a volume ratio of 3:

1.

8. The method for stabilizing and preparing high-purity, low-impurity sodium hypochlorite according to claim 2, characterized in that, The adhesive includes a PVDF adhesive of model number FLEX 2801.

9. The method for stabilizing and preparing high-purity, low-impurity sodium hypochlorite according to claim 2, characterized in that, The solvent is N-methylpyrrolidone.