Electro-Fenton cathode for removing organic pollutants in salt-containing wastewater as well as preparation method and application of electro-Fenton cathode

Abstract

The invention provides an electro-Fenton cathode for removing organic pollutants in salt-containing wastewater as well as a preparation method and application of the electro-Fenton cathode, and belongs to the technical field of wastewater treatment. The preparation method comprises the following steps: firstly, taking biomass cellulose as a substrate material to form carbon aerogel, then mixing the carbon aerogel with a mixed salt solution containing ferric salt and copper salt, and carrying out hydrothermal reaction and in-situ growth to prepare a carbon aerogel electrode, namely the electro-Fenton cathode, the electrode can generate H2O2 in situ at a cathode of an electro-catalysis system and promote H2O2 decomposition in situ to generate. OH, and the electrochemical performance of the electro-Fenton cathode is improved. Therefore, organic pollutants in the wastewater are efficiently degraded. Compared with the prior art, the electro-Fenton cathode synthesized by using the green biomass cellulose as a main component has a cross-linked three-dimensional network and a high specific surface area; cu and Fe grow on the surface of the carbon aerogel in situ in the form of iron-copper layered double hydroxides to serve as the electro-Fenton cathode, and efficient removal of organic pollutants can be achieved under the mild condition.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to an electric Fenton cathode for the removal of organic pollutants from saline wastewater, its preparation method, and its application. Background Technology

[0002] Acetaminophen (ACT), also known as paracetamol, is a widely used analgesic and antipyretic drug worldwide. Since its use in disease treatment in 1955, ACT has frequently been found in organic matter in biodegradable wastewater due to its low human absorption rate (approximately 5-15%) and high water solubility (12.78 g / L). Because of its poor biodegradability, current tertiary treatment methods are not very effective in preventing its accumulation in plant-based wastewater. Furthermore, the large amounts of inorganic salts required in drug synthesis contribute to the formation of saline wastewater, necessitating the development of more effective methods to ensure the degradation of drug contaminants.

[0003] Advanced oxidation technologies, also known as deep oxidation technologies, integrate the latest research results from various related disciplines such as optics, electronics, acoustics, magnetism, and materials science, and are expected to become a "killer application" for the treatment of organic waste, especially recalcitrant organic waste. They mainly include electrochemical oxidation, wet oxidation, supercritical water oxidation, photocatalytic oxidation, and ultrasonic degradation. Among these, the traditional Fenton oxidation method is favored due to its simple operation, rapid reaction, and ability to produce flocculation compared to other advanced oxidation processes. Specifically, the electro-Fenton method utilizes H₂O₂ and Fe produced by electrochemical methods... 2+ As a continuous source of Fenton's reagent, the two react immediately to generate highly reactive hydroxyl radicals (•OH), which degrade organic matter. Essentially, Fenton's reagent is directly generated during electrolysis. Furthermore, the electro-Fenton method possesses two key characteristics, making it a suitable choice. First, the Fenton reaction generates a large amount of hydroxyl radicals (•OH) in solution, ensuring efficient degradation of drug contaminants. Second, in the electro-Fenton system, the continuous in-situ generation of H₂O₂ through the two-electron reaction of oxygen allows the use of inorganic salts in saline wastewater as an electrolyte. However, the electro-Fenton method still has some shortcomings that limit its application in practical wastewater treatment, such as the high cost of electrode materials and a narrow operating pH range. Summary of the Invention

[0004] The purpose of this invention is to provide an electro-Fenton cathode for the removal of organic pollutants from saline wastewater, its preparation method, and its application. The method provided by this invention uses widely available materials, and the prepared electro-Fenton cathode has a three-dimensional network structure, a large specific surface area, high porosity, and abundant oxygen-containing groups. It can generate H2O2 in situ and promote the decomposition of H2O2 to generate ·OH, thus efficiently degrading organic pollutants in wastewater.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing an electro-Fenton cathode for the removal of organic pollutants from saline wastewater, comprising the following steps: synthesizing carbon aerogel using biomass cellulose as a substrate material; and growing Cu and Fe in situ on the surface of the carbon aerogel in the form of an iron-copper layered bimetallic hydroxide to serve as an electro-Fenton cathode, thereby obtaining an electro-Fenton cathode for the removal of organic pollutants from saline wastewater.

[0007] Preferably, it includes the following steps:

[0008] (1) Sodium hydroxide, urea and water are mixed and stored at low temperature to obtain a mixed solution;

[0009] (2) Add biomass cellulose to the mixed solution obtained in step (1), and stir, mold, seal and freeze dry in sequence to obtain dry gel;

[0010] (3) The dry gel obtained in step (2) is calcined under nitrogen protection and then cooled to obtain carbon aerogel;

[0011] (4) After mixing iron salt, copper salt, urea and water, a mixed salt solution is obtained;

[0012] The carbon aerogel obtained in step (3) is immersed in the mixed salt solution, and hydrothermal reaction and post-treatment are carried out in sequence to obtain an electro-Fenton cathode for the removal of organic pollutants in saline wastewater.

[0013] Preferably, in step (1), the mass ratio of sodium hydroxide, urea and water is 7:(10~15):(70~120).

[0014] Preferably, the biomass cellulose in step (2) is at least one of cotton lint, cotton, and hemp.

[0015] Preferably, the ratio of the mass of biomass cellulose to the volume of the mixed solution in step (2) is (1~7) g: 100 mL.

[0016] Preferably, the calcination conditions in step (3) are as follows: under a nitrogen atmosphere with a nitrogen flow rate of 300~600 mL / min, the temperature is increased to 700~900℃ at a heating rate of 2~6℃ per minute and maintained for 2~4 hours.

[0017] Preferably, in step (4), the iron salt is at least one of ferric nitrate nonahydrate and ferric chloride hexahydrate; the copper salt is at least one of copper nitrate trihydrate and anhydrous copper chloride; and the molar ratio of the iron salt, copper salt and urea is 1:1:(14~24).

[0018] Preferably, the temperature of the hydrothermal reaction in step (4) is 90~160℃, and the time of the hydrothermal reaction is 16~24h.

[0019] The present invention also provides an electro-Fenton cathode for the removal of organic pollutants in saline wastewater prepared by the preparation method described above.

[0020] The present invention also provides an electro-Fenton cathode for the removal of organic pollutants in saline wastewater prepared by the preparation method described above, or the application of the electro-Fenton cathode for the removal of organic pollutants in saline wastewater in the degradation of organic pollutants in wastewater.

[0021] Compared with existing Fenton cathodes, the Fenton cathode prepared in this invention for the removal of organic pollutants from saline wastewater has the following characteristics:

[0022] (1) The electro-Fenton cathode synthesized in this invention has many advantages:

[0023] (i) Biomass cellulose, as a substrate material, is a green biomass. The carbon aerogel synthesized from it has advantages such as large specific surface area, high porosity, and rich oxygen-containing groups, and is widely available.

[0024] (ii) The synthesized electro-Fenton cathode can generate H2O2 in situ and promote the decomposition of H2O2 to generate ·OH, which efficiently degrades organic pollutants in wastewater.

[0025] (iii) Through hydrothermal reaction, copper-iron compounds are grown in situ on the surface of the carbon aerogel synthesized from biomass cellulose, which can increase the introduced surface roughness, further enhance the two-electron reaction of oxygen, and thus increase the amount of H2O2 generated.

[0026] (2) Compared with the traditional electro-Fenton technology, the electro-Fenton cathode based on cellulose carbon aerogel constructed in this invention can overcome the problems of expensive electrode materials and narrow pH range because the main material, biomass cellulose, is derived from natural cellulose. The introduction of Cu can improve the pH adaptability of the catalyst. Secondly, the presence of Fe / Cu bimetal on the cathode surface in the form of layered bimetallic hydroxide can improve the electron transfer rate of the electrode, further realizing the efficient degradation of organic pollutants in wastewater in a wide pH range, and has broad application prospects. Attached Figure Description

[0027] Figure 1 This is a schematic diagram illustrating the mechanism of the electro-Fenton cathode used for the removal of organic pollutants from saline wastewater in an application example of the present invention during the degradation of acetaminophen.

[0028] Figure 2The XRD pattern of the electro-Fenton cathode for the removal of organic pollutants from saline wastewater prepared in Example 1 of the present invention;

[0029] Figure 3 This is a SEM image of the surface of the electro-Fenton cathode prepared for the removal of organic pollutants from saline wastewater in Example 1 of the present invention. Detailed Implementation

[0030] This invention provides a method for preparing an electro-Fenton cathode for the removal of organic pollutants from saline wastewater, comprising the following steps: synthesizing carbon aerogel using biomass cellulose as a substrate material; and growing Cu and Fe in situ on the surface of the carbon aerogel in the form of an iron-copper layered bimetallic hydroxide to serve as an electro-Fenton cathode, thereby obtaining an electro-Fenton cathode for the removal of organic pollutants from saline wastewater.

[0031] In this invention, the method for preparing the electro-Fenton cathode for removing organic pollutants from saline wastewater preferably includes the following steps:

[0032] (1) Sodium hydroxide, urea and water are mixed and stored at low temperature to obtain a mixed solution;

[0033] (2) Add biomass cellulose to the mixed solution obtained in step (1), and stir, mold, seal and freeze dry in sequence to obtain dry gel;

[0034] (3) The dry gel obtained in step (2) is calcined under nitrogen protection and then cooled to obtain carbon aerogel;

[0035] (4) After mixing iron salt, copper salt, urea and water, a mixed salt solution is obtained;

[0036] The carbon aerogel obtained in step (3) is immersed in the mixed salt solution, and hydrothermal reaction and post-treatment are carried out in sequence to obtain an electro-Fenton cathode for the removal of organic pollutants in saline wastewater.

[0037] Unless otherwise specified, all raw materials used in this invention are commercially available products in the art.

[0038] This invention involves mixing sodium hydroxide, urea, and water, and then storing the mixture at low temperature to obtain a mixed solution.

[0039] In this invention, the preferred mass ratio of sodium hydroxide, urea, and water is 7:(10~15):(70~120), more preferably 7:12:(80~100). This invention controls the mass ratio of sodium hydroxide, urea, and water within the above range to ensure that the subsequent biomass cellulose can be completely dissolved. In this invention, the low-temperature storage is preferably performed at -18°C for at least 2 hours.

[0040] After obtaining the mixed solution, the present invention adds biomass cellulose to the mixed solution, and then stirs, molds, seals and freezes dry in sequence to obtain a dry gel.

[0041] In this invention, the biomass cellulose is preferably at least one of cotton lint, cotton, and hemp. In this invention, the mass ratio of the biomass cellulose to the volume of the mixed solution is preferably (1-7) g:100 mL, more preferably (2-5) g:100 mL. This invention controls the mass ratio of the biomass cellulose to the volume of the mixed solution within the above range to ensure that the biomass cellulose is completely dissolved. This invention does not impose any special restrictions on the stirring method; uniform mixing of all components is sufficient. This invention does not impose any special restrictions on the molding and sealing methods; well-known technical solutions in the art can be used. In this invention, the freeze-drying temperature is preferably -20 to -80°C, more preferably -50°C; the freeze-drying time is preferably 2-4 days, more preferably 3 days. This invention controls the freeze-drying temperature and time within the above range to ensure the formation of a dry gel.

[0042] After obtaining the dry gel, the present invention calcines the dry gel under nitrogen protection and then cools it to obtain a carbon aerogel.

[0043] In this invention, the preferred calcination conditions are: heating to 700-900°C at a nitrogen atmosphere with a nitrogen flow rate of 300-600 mL / min, and holding for 2-4 hours. This invention ensures the synthesis of carbon aerogel through calcination under these conditions. In this invention, the preferred cooling method is reducing to room temperature at a cooling rate of 2-6°C per minute. This invention controls the cooling rate to prevent damage to the carbon aerogel caused by excessively rapid cooling.

[0044] This invention involves mixing iron salts, copper salts, urea, and water to obtain a mixed salt solution.

[0045] In this invention, the iron salt is preferably at least one of ferric nitrate nonahydrate and ferric chloride hexahydrate. In this invention, the copper salt is preferably at least one of copper nitrate trihydrate and anhydrous copper chloride. In this invention, the molar ratio of the iron salt, copper salt, and urea is preferably 1:1:(14~24), more preferably 1:1:(16~20). This invention controls the molar ratio of the iron salt, copper salt, and urea within the above range to ensure that the synthesized compound is an iron-copper bimetallic hydroxide.

[0046] After obtaining the mixed salt solution and carbon aerogel, the present invention immerses the carbon aerogel in the mixed salt solution and performs hydrothermal reaction and post-treatment in sequence to obtain an electro-Fenton cathode for the removal of organic pollutants in saline wastewater.

[0047] In this invention, the hydrothermal reaction is preferably carried out in a polytetrafluoroethylene-lined reactor. The preferred temperature for the hydrothermal reaction is 90-160°C; the preferred reaction time is 9-24 hours. This invention controls the temperature and time of the hydrothermal reaction within the above ranges to ensure the synthesis of iron-copper bimetallic hydroxide on the carbon aerogel surface. The post-treatment preferably includes: sequentially cooling, rinsing with deionized water, and drying the product of the hydrothermal reaction. This invention does not impose any particular limitation on the cooling method; cooling to room temperature using techniques well-known in the art is sufficient. This invention does not impose any particular limitation on the deionized water rinsing method; removing excess impurities using techniques well-known in the art is sufficient. This invention does not impose any particular limitation on the drying method; removing residual solvent is sufficient.

[0048] This invention provides a method for preparing an electro-Fenton cathode for the removal of organic pollutants from saline wastewater. Using biomass cellulose as the substrate material, the cellulose is dissolved in an alkaline solution, freeze-dried, and carbonized at high temperature to form a carbon aerogel. This aerogel is then mixed with a mixed salt solution containing iron and copper salts and subjected to a hydrothermal reaction to grow the carbon aerogel electrode in situ, thus obtaining the electro-Fenton cathode. This electrode can generate H2O2 in situ within the electrocatalytic system and promote the decomposition of H2O2 to produce ·OH, thereby efficiently degrading organic pollutants in wastewater. Compared with existing technologies, the electro-Fenton cathode synthesized using green biomass cellulose as the main component has a cross-linked three-dimensional network and a high specific surface area. The in-situ growth of Cu and Fe on the surface of the carbon aerogel as the electro-Fenton cathode can achieve efficient removal of organic pollutants under mild conditions. The raw materials used in this invention are inexpensive, the operation is convenient, and it has broad application prospects in the field of practical wastewater treatment.

[0049] The present invention also provides an electro-Fenton cathode for the removal of organic pollutants in saline wastewater prepared by the preparation method described above.

[0050] The present invention also provides an electro-Fenton cathode for the removal of organic pollutants in saline wastewater prepared by the preparation method described above, or the application of the electro-Fenton cathode for the removal of organic pollutants in saline wastewater in the degradation of organic pollutants in wastewater.

[0051] In this invention, the application of the electro-Fenton cathode for removing organic pollutants from saline wastewater in the degradation of organic pollutants in wastewater preferably includes the following steps:

[0052] An electro-Fenton system was constructed using the aforementioned electro-Fenton cathode for the removal of organic pollutants from saline wastewater and a commercial DSA electrode to degrade organic pollutants in wastewater in a single-chamber electrolytic cell. Na2SO4 with a concentration of 0.05~0.40 mol / L was used as the supporting electrolyte. The pH value of the degradation reaction system in the single-chamber electrolytic cell was 3~9, and the current was 100~300mA. Before the degradation reaction started, air was aerated at a rate of 1L / min for 30min. During the degradation reaction, the air aeration rate was adjusted to 0.4~1L / min.

[0053] In this invention, the organic pollutant is preferably at least one selected from acetaminophen, carbamazepine, sulfamethoxazole, and methylene blue. In this invention, the concentration of the organic pollutant in the wastewater is 5-50 mg / L.

[0054] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0055] Unless otherwise specified, all experiments were repeated three times, and the results are expressed as averages.

[0056] Example 1

[0057] A method for preparing an electro-Fenton cathode for the removal of organic pollutants from saline wastewater, comprising the following steps:

[0058] (1) Weigh appropriate amounts of sodium hydroxide, urea and water and stir to mix evenly. The mass ratio of sodium hydroxide, urea and water is 7:12:80. Place the mixture in a refrigerator at -18℃ for more than 2 hours to obtain a mixed solution.

[0059] (2) Add 2.5g of cotton wool to the mixed solution obtained in step (1), stir until the cotton wool is completely dissolved, pour into a mold and seal, freeze dry at -50℃ for 3 days to obtain dry gel;

[0060] (3) The dry gel obtained in step (2) is placed in a tube furnace and heated to 700°C at a nitrogen atmosphere with a nitrogen flow rate of 300 mL / min. The temperature is maintained for 2 hours and then cooled to room temperature at the same cooling rate to obtain carbon aerogel.

[0061] (4) Weigh out ferric nitrate nonahydrate, copper nitrate trihydrate and urea in a molar ratio of 1:1:20 and add them to water and stir until well mixed to obtain a mixed salt solution;

[0062] The carbon aerogel obtained in step (3) is immersed in the mixed salt solution and placed in a reaction vessel lined with polytetrafluoroethylene. The reaction is carried out in a muffle furnace at 120°C for 15 hours. After cooling, the product of the hydrothermal reaction is taken out and rinsed several times with deionized water. Then it is dried to obtain an electro-Fenton cathode for the removal of organic pollutants in saline wastewater.

[0063] Figure 2 The XRD pattern of the electro-Fenton cathode prepared for the removal of organic pollutants from saline wastewater in Example 1 of this invention. Figure 2 It can be seen that, Figure 2 The presence of characteristic peaks for carbon, as well as hydroxides of copper and iron, indicates that Example 1 successfully prepared the electro-Fenton cathode for the removal of organic pollutants from saline wastewater.

[0064] Figure 3 This is a SEM image of the surface of the electro-Fenton cathode prepared in Example 1 of the present invention for the removal of organic pollutants from saline wastewater. Figure 3 It can be seen that the surface of the electro-Fenton cathode prepared in Example 1 for the removal of organic pollutants in saline wastewater has a large number of spherical objects formed by nanosheets, which significantly increases its surface area and increases the number of active sites, thereby improving its electron transfer rate.

[0065] Application Example 1

[0066] The application of an electro-Fenton cathode for the removal of organic pollutants from saline wastewater in the degradation of organic pollutants in wastewater includes the following steps:

[0067] Using the electro-Fenton cathode prepared in Example 1 and a commercially available DSA electrode, p-acetaminophen (ACT, 150 mL, 20 mg / L) was degraded in a single-chamber electrolytic cell. The current was kept constant at 300 mA, the pH of the degradation reaction system was 3, and 0.05 M Na₂SO₄ was used as the supporting electrolyte. Before the degradation reaction began, air was aerated at a rate of 1 L / min for 30 min, and the aeration rate remained constant at 1 L / min during the degradation process. Experimental results showed that the electro-Fenton cathode prepared in Example 1 achieved a 100% degradation efficiency for ACT and a 67% removal efficiency for TOC within 1 hour.

[0068] Example 2:

[0069] A method for preparing an electro-Fenton cathode for the removal of organic pollutants from saline wastewater, comprising the following steps:

[0070] (1) Weigh appropriate amounts of sodium hydroxide, urea and water and stir to mix evenly. The mass ratio of sodium hydroxide, urea and water is 7:12:80. Place the mixture in a refrigerator at -18℃ for more than 2 hours to obtain a mixed solution.

[0071] (2) Add 2.5g of cotton wool to the mixed solution obtained in step (1), stir until the cotton wool is completely dissolved, pour into a mold and seal, freeze dry at -50℃ for 3 days to obtain dry gel;

[0072] (3) The dry gel obtained in step (2) is placed in a tube furnace and heated to 700°C at a nitrogen atmosphere with a nitrogen flow rate of 300 mL / min. The temperature is maintained for 2 hours and then cooled to room temperature at the same cooling rate to obtain carbon aerogel.

[0073] (4) Weigh out ferric nitrate nonahydrate, copper nitrate trihydrate and urea in a molar ratio of 2:1:20, add them to water and stir until well mixed to obtain a mixed salt solution;

[0074] The carbon aerogel obtained in step (3) is immersed in the mixed salt solution and placed in a reaction vessel lined with polytetrafluoroethylene. The reaction is carried out in a muffle furnace at 120°C for 15 hours. After cooling, the product of the hydrothermal reaction is taken out and rinsed several times with deionized water. Then it is dried to obtain an electro-Fenton cathode for the removal of organic pollutants in saline wastewater.

[0075] Application Example 2

[0076] The application of an electro-Fenton cathode for the removal of organic pollutants from saline wastewater in the degradation of organic pollutants in wastewater includes the following steps:

[0077] Using the Fenton cathode prepared in Example 1 and a commercial DSA electrode, an electro-Fenton system was used to degrade acetaminophen (ACT, 150 mL, 20 mg / L) in a single-chamber electrolytic cell. The current was kept constant at 300 mA, the pH of the degradation reaction system was 3, and 0.05 M Na2SO4 was used as the supporting electrolyte. Before the degradation reaction started, the system was aerated with air at a rate of 1 L / min for 30 min. During the degradation process, the aeration rate of air was kept constant at 1 L / min. Five repeated experiments were conducted under the same conditions. The degradation efficiencies of the Fenton cathode prepared in Example 2 for ACT after 1 hour of reaction were measured to be 100%, 100%, 98.86%, 97.12%, and 96.31%, respectively. It can be seen that after repeating the degradation reaction five times, the degradation efficiency of the Fenton cathode prepared in Example 2 for ACT decreased by only 4%, indicating that the Fenton cathode prepared in this invention for the removal of organic pollutants in saline wastewater has good reusability.

[0078] Example 3:

[0079] A method for preparing an electro-Fenton cathode for the removal of organic pollutants from saline wastewater, comprising the following steps:

[0080] (1) Weigh appropriate amounts of sodium hydroxide, urea and water and stir to mix evenly. The mass ratio of sodium hydroxide, urea and water is 7:12:80. Place the mixture in a refrigerator at -18℃ for more than 2 hours to obtain a mixed solution.

[0081] (2) Add 2.5g of cotton wool to the mixed solution obtained in step (1), stir until the cotton wool is completely dissolved, pour into a mold and seal, freeze dry at -50℃ for 3 days to obtain dry gel;

[0082] (3) The dry gel obtained in step (2) is placed in a tube furnace and heated to 700°C at a nitrogen atmosphere with a nitrogen flow rate of 300 mL / min. The temperature is maintained for 2 hours and then cooled to room temperature at the same cooling rate to obtain carbon aerogel.

[0083] (4) Weigh out ferric nitrate nonahydrate, copper nitrate trihydrate and urea in a molar ratio of 2:1:20, add them to water and stir until well mixed to obtain a mixed salt solution;

[0084] The carbon aerogel obtained in step (3) is immersed in the mixed salt solution and placed in a reaction vessel lined with polytetrafluoroethylene. The reaction is carried out in a muffle furnace at 120°C for 15 hours. After cooling, the product of the hydrothermal reaction is taken out and rinsed several times with deionized water. Then it is dried to obtain an electro-Fenton cathode for the removal of organic pollutants in saline wastewater.

[0085] Application Example 3

[0086] The application of an electro-Fenton cathode for the removal of organic pollutants from saline wastewater in the degradation of organic pollutants in wastewater includes the following steps:

[0087] Using the Fenton system composed of the Fenton cathode prepared in Example 3 and a commercial DSA electrode, acetaminophen (ACT, 150 mL, 20 mg / L) was degraded in a single-chamber electrolytic cell. The current was kept constant at 300 mA, and 0.05 M Na2SO4 was used as the supporting electrolyte. Before the degradation reaction started, air was aerated at a rate of 1 L / min for 30 min. During the degradation process, the air aeration rate was kept constant at 1 L / min. ACT was degraded under pH conditions of 3, 5, 7, and 9. The experimental results showed that under pH conditions of 3, 5, 7, and 9, the degradation efficiency of the Fenton cathode prepared in Example 3 for ACT after 1 hour of reaction was 100%, 95.36%, 90.99%, and 88.98%, respectively. This demonstrates that the Fenton cathode prepared in Example 3 for the removal of organic pollutants from saline wastewater has good pH suitability.

[0088] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an electro-Fenton cathode for the removal of organic pollutants from saline wastewater, characterized in that, Includes the following steps: Carbon aerogel was synthesized using biomass cellulose as the substrate material; Cu and Fe were grown in situ on the surface of the carbon aerogel in the form of iron-copper layered bimetallic hydroxide to serve as an electro-Fenton cathode, thus obtaining an electro-Fenton cathode for the removal of organic pollutants from saline wastewater.

2. The preparation method according to claim 1, characterized in that, Includes the following steps: (1) Sodium hydroxide, urea and water are mixed and stored at low temperature to obtain a mixed solution; (2) Add biomass cellulose to the mixed solution obtained in step (1), and stir, mold, seal and freeze dry in sequence to obtain dry gel; (3) The dry gel obtained in step (2) is calcined under nitrogen protection and then cooled to obtain carbon aerogel; (4) After mixing iron salt, copper salt, urea and water, a mixed salt solution is obtained; The carbon aerogel obtained in step (3) is immersed in the mixed salt solution, and hydrothermal reaction and post-treatment are carried out in sequence to obtain an electro-Fenton cathode for the removal of organic pollutants in saline wastewater.

3. The preparation method according to claim 2, characterized in that, In step (1), the mass ratio of sodium hydroxide, urea and water is 7:(10~15):(70~120).

4. The preparation method according to claim 2, characterized in that, In step (2), the biomass cellulose is at least one of cotton lint, cotton, and hemp.

5. The preparation method according to claim 2, characterized in that, In step (2), the ratio of the mass of biomass cellulose to the volume of the mixed solution is (1~7) g: 100 mL.

6. The preparation method according to claim 2, characterized in that, The calcination conditions in step (3) are as follows: under a nitrogen atmosphere with a nitrogen flow rate of 300-600 mL / min, the temperature is increased to 700-900℃ at a heating rate of 2-6℃ per minute and maintained for 2-4 hours.

7. The preparation method according to claim 2, characterized in that, In step (4), the iron salt is at least one of ferric nitrate nonahydrate and ferric chloride hexahydrate; the copper salt is at least one of copper nitrate trihydrate and anhydrous copper chloride; and the molar ratio of the iron salt, copper salt and urea is 1:1:(14~24).

8. The preparation method according to claim 2, characterized in that, The temperature of the hydrothermal reaction in step (4) is 90~160℃, and the time of the hydrothermal reaction is 16~24h.

9. An electro-Fenton cathode for removing organic pollutants from saline wastewater, prepared by the method according to any one of claims 1 to 8.

10. The application of an electro-Fenton cathode for the removal of organic pollutants from saline wastewater prepared by the preparation method according to any one of claims 1 to 8, or the electro-Fenton cathode for the removal of organic pollutants from saline wastewater according to claim 9, in the degradation of organic pollutants in wastewater.

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