Preparation method of iron-nitrogen doped magnetic ozone catalyst and ozone electro-catalysis coupling system

Abstract

The application discloses a preparation method of an iron-nitrogen doped magnetic ozone catalyst and an ozone electrocatalysis coupling system. The preparation method comprises preparation of an iron-nitrogen doped ozone catalyst and preparation of an iron-nitrogen doped magnetic ozone catalyst. The ozone electrocatalysis coupling system comprises a coupling catalytic reaction cylinder and an internal circulation reaction cylinder. A water inlet is arranged at the bottom of one side of the coupling catalytic reaction cylinder, and the top of the other side is communicated with the internal circulation reaction cylinder through a water pipe. A plurality of anode plates and cathode plates are arranged in the coupling catalytic reaction cylinder in a vertical direction. The cathode plate is an ozone aeration membrane plate, and ozone is aerated through the electrode plate. A spiral coil is arranged in the internal circulation reaction cylinder. The ozone catalyst prepared by the method has high catalytic ozone oxidation efficiency and effect, and improves the wastewater treatment effect.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a method for preparing an iron-nitrogen-doped magnetic ozone catalyst and an ozone electrocatalytic coupling system. Background Technology

[0002] Advanced Oxidation Processes (AOPs) are technologies that generate a large number of highly oxidizing free radicals under conditions of catalysts, light, and electricity, thereby oxidizing organic pollutants in wastewater and achieving efficient degradation. Currently, commonly used AOPs include ozone catalysis, electrocatalysis, photocatalysis, and Fenton technology. Ozone, under the action of a catalyst, generates active groups such as hydroxyl radicals, exhibiting a high redox potential in water and strong oxidizing power, making it suitable for wastewater treatment. Furthermore, ozone degradation of pollutants does not produce secondary pollution, thus it is hailed as an "ideal green strong oxidant." However, ozone has low solubility in water, poor mass transfer, and short contact time with the catalyst, resulting in low ozone utilization. Ozone catalysis also has high energy consumption and high treatment costs. In addition, traditional ozone packed bed reactors for catalytic ozone oxidation cannot guarantee sufficient contact between the gas, solid, and liquid phases, leading to low overall catalytic efficiency. Organic films form on the catalyst surface, shortening catalyst lifespan, and catalyst replacement requires shutting down the entire equipment, resulting in low operating efficiency. These problems limit the large-scale application of ozone catalytic oxidation technology in the field of water treatment. Summary of the Invention

[0003] Based on the technical problems mentioned in the background art, the purpose of this invention is to provide a method for preparing an iron-nitrogen-doped magnetic ozone catalyst and an ozone electrocatalytic coupling system, so as to improve the efficiency and effect of catalytic ozone oxidation and thus improve the wastewater treatment effect.

[0004] The present invention proposes a method for preparing an iron-nitrogen-doped magnetic ozone catalyst, wherein the iron-nitrogen-doped magnetic ozone catalyst is based on ordered mesoporous carbon, and iron and nitrogen elements are doped to obtain an iron-nitrogen-doped ozone catalyst, which is then magnetically modified and obtained through a hydrothermal reaction.

[0005] The preparation of the iron-nitrogen-doped ozone catalyst includes the following steps:

[0006] Step 11: Place 1 part SBA-15, 1.25 parts sucrose, 0.14 parts H2SO4 and 5 parts H2O into a mixing container in sequence and stir well;

[0007] Step 12: Dry the solution from Step 11 at 60-100°C for 12 hours, and then carbonize it at 160°C for 6 hours;

[0008] Step 13: When the sample from Step 12 turns dark brown or black, add 0.4 parts sucrose, 0.2 parts urea, 0.1-0.2 parts ferrous chloride and 0.1-0.2 parts ferric chloride, 0.09 parts H2SO4 and 5 parts H2O to the mixing container in sequence.

[0009] Step 14: Dry the solution from Step 13 at 60-100℃ for 12 hours, then carbonize it at 160℃ to obtain a black powder;

[0010] Step 15: Calcining the black powder from Step 14 in a nitrogen atmosphere at 800-900°C for 1-2 hours, wherein the heating rate is 5°C·min-1;

[0011] Step 16: Cool the material obtained in Step 15 to room temperature and repeatedly wash it with a strong alkaline solution to remove the silicon template;

[0012] The preparation of the iron-nitrogen-doped magnetic ozone catalyst includes the following steps:

[0013] Step 21: Disperse 1-3 parts of the iron-nitrogen-doped ozone catalyst in 70-200 parts of ethylene glycol solution and sonicate for 30 min;

[0014] Step 22: Add 1-3 parts of magnetic main catalyst and 1-3 parts of magnetic co-catalyst to the solution obtained in step 21, and stir magnetically for 30 minutes;

[0015] Step 23: Transfer the solution obtained in Step 22 to a stainless steel reactor with a polytetrafluoroethylene liner of 250 parts, react at 180-200℃ for 4-8 hours, and then allow it to cool naturally at room temperature.

[0016] Step 24: Wash the precipitate obtained in step 23 repeatedly with ultrapure water and ethanol several times, and finally dry it at 60°C for 12 hours. The resulting dark brown solid is iron-nitrogen doped magnetically ordered mesoporous carbon.

[0017] Furthermore, the strong alkaline solution mentioned in step 16 is an aqueous solution of sodium hydroxide or potassium hydroxide with a mass percentage of 8-12%.

[0018] Furthermore, in step 22, the magnetic main catalyst is selected from one or more of ferric citrate, ferrous nitrate, and ferric nitrate, and the magnetic co-catalyst is selected from one or more of potassium permanganate, copper nitrate, and nickel nitrate.

[0019] An ozone electrocatalytic coupling system using the above-mentioned catalyst includes a coupling catalytic reaction cylinder and an inner circulation reaction cylinder. The bottom of one side of the coupling catalytic reaction cylinder is provided with a water inlet, and the top of the other side is connected to the inner circulation reaction cylinder through a water pipe. Multiple anode plates and cathode plates are arranged vertically and alternately inside the coupling catalytic reaction cylinder, and the cathode plate is an ozone aeration membrane plate. A spiral coil is provided inside the inner circulation reaction cylinder.

[0020] Furthermore, the bottom of the internal circulation reaction cylinder is connected to the coupled catalytic reaction cylinder via a reflux pipe.

[0021] Furthermore, the bottom of the internal circulation reaction cylinder on the side opposite to the water pipe is provided with a water outlet, and the top of the internal circulation reaction cylinder is connected to an air outlet line.

[0022] Furthermore, the surface of the spiral coil is coated with a hydrophobic coating, which is made of siloxane reagent.

[0023] Furthermore, an ozone catalyst is added to the coupled catalytic reaction vessel at a dosage of 0.2-2 g / L.

[0024] Furthermore, the spiral coil is intermittently energized, with an energization rate of 10%-40%.

[0025] Furthermore, at room temperature, the residence time of wastewater in the ozone electrocatalytic coupling system is 10-120 min.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. Coupling electrocatalysis and ozone catalysis enriches the ·OH conversion pathway; applying powdered ozone catalyst to electrocatalysis, under the attraction of the electric field, prolongs the residence time of the catalyst and the contact time between the catalyst and ozone, which helps to improve ozone utilization; ozone, through membrane aeration, helps the powdered ozone catalyst to be fully fluidized under the influence of electric field, airflow and water flow disturbance, improving mass transfer efficiency and ozone utilization, and avoiding uneven distribution of catalyst on the electrode plate surface due to electric field attraction.

[0028] 2. Ordered mesoporous carbon doped with iron and nitrogen elements and loaded with catalytically active components is selected as the catalyst. It has a large specific surface area and strong adsorption capacity for organic pollutants in water. The use of iron and nitrogen doping allows the metallic iron and non-metallic nitrogen elements to synergistically promote the catalytic decomposition of ozone. Furthermore, the doping with nitrogen increases the applicability of the catalyst to wastewater with different pH levels. The loading of magnetic oxides ensures a uniform distribution of active sites, further promoting the decomposition of ozone to generate hydroxyl radicals, thereby improving the efficiency of ozone treatment of organic matter and increasing the utilization rate of ozone. At the same time, the catalyst itself is lighter and smaller than conventional particulate catalysts, has magnetic properties, is easy to recover, and will not increase the burden of subsequent wastewater treatment.

[0029] 3. A hydrophobic coating is applied to the surface of the spiral coil, thus forming a gas-liquid-solid three-phase interface on the outside of the spiral coil. The ozone concentration at the three-phase interface is increased, raising the ozone concentration in the aqueous reactant substrate (which is only ~1 mg / L in water at 25°C) to 50 mg / L in the gas phase. At 100 mg / L, the residence time of ozone also increases, thus improving ozone oxidation efficiency and utilization.

[0030] 4. Through the attraction of the energized spiral coil to magnetic light materials, the magnetic catalyst is adsorbed and concentrated near the energized spiral coil; the porous catalyst adsorbs organic pollutants, and the organic matter forms a super-enrichment at the three-phase interface; therefore, ozone catalyst, pollutants, and ozone are locally enriched at the three-phase interface, which increases the contact time between the catalyst and ozone, improves the utilization rate of ozone, further improves the catalytic degradation efficiency, and the organic matter adsorbed on the catalyst surface can also be efficiently degraded, thus achieving the effect of cleaning the catalyst while degrading pollutants. Attached Figure Description

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Figure 1 This is a schematic diagram of a preferred embodiment of the present invention.

[0033] 1. Water inlet, 2. Anode plate, 3. Coupled catalytic reaction cylinder, 4. Catalyst, 5. Cathode plate, 6. Water pipe, 7. Internal circulation reaction cylinder, 8. Gas outlet pipeline, 9. Spiral coil, 10. Water outlet, 11. Return pipe. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0035] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing and simplifying the invention, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.

[0037] Example 1

[0038] This embodiment provides a method for preparing an iron-nitrogen-doped magnetic ozone catalyst. The iron-nitrogen-doped magnetic ozone catalyst uses ordered mesoporous carbon as a matrix, and obtains an iron-nitrogen-doped ozone catalyst by doping with iron and nitrogen elements. Then, it undergoes magnetic modification and is obtained through a hydrothermal reaction.

[0039] The preparation of the iron-nitrogen-doped ozone catalyst includes the following steps:

[0040] Step 11: Place 1g SBA-15, 1.25g sucrose, 0.14g H2SO4 and 5g H2O into a mixing container in sequence and stir well;

[0041] Step 12: Dry the solution from Step 11 at 60°C for 12 hours, and then carbonize it at 160°C for 6 hours;

[0042] Step 13: When the sample from Step 12 turns dark brown or black, add 0.4g sucrose, 0.2g urea, 0.1g ferrous chloride, 0.1g ferric chloride, 0.09g H2SO4, and 5g H2O to the mixing container in sequence.

[0043] Step 14: Dry the solution from Step 13 at 60°C for 12 hours, then carbonize it at 160°C to obtain a black powder;

[0044] Step 15: Calcining the black powder obtained in Step 14 at 800°C in a nitrogen atmosphere for 1-2 hours, wherein the heating rate is 5°C·min. -1 ;

[0045] Step 16: Cool the material obtained in Step 15 to room temperature and repeatedly wash it with a strong alkaline solution to remove the silicon template;

[0046] The preparation of the iron-nitrogen-doped magnetic ozone catalyst includes the following steps:

[0047] Step 21: Disperse 1g of the iron-nitrogen-doped ozone catalyst in 70g of ethylene glycol solution and sonicate for 30min;

[0048] Step 22: Add 1g of magnetic main catalyst and 1g of magnetic co-catalyst to the solution obtained in step 21, and stir magnetically for 30min;

[0049] Step 23: Transfer the solution obtained in step 22 to a 250g stainless steel reactor with a polytetrafluoroethylene liner, react at 180℃ for 4 hours, and then allow it to cool naturally at room temperature.

[0050] Step 24: Wash the precipitate obtained in step 23 repeatedly with ultrapure water and ethanol several times, and finally dry it at 60°C for 12 hours. The resulting dark brown solid is iron-nitrogen doped magnetically ordered mesoporous carbon.

[0051] The strong alkaline solution mentioned in step 16 is an aqueous solution of sodium hydroxide or potassium hydroxide with a mass percentage of 8%.

[0052] In step 22, the magnetic main catalyst is iron citrate, and the magnetic co-catalyst is potassium permanganate.

[0053] Example 2

[0054] This embodiment provides a method for preparing an iron-nitrogen-doped magnetic ozone catalyst. The iron-nitrogen-doped magnetic ozone catalyst uses ordered mesoporous carbon as a matrix, and obtains an iron-nitrogen-doped ozone catalyst by doping with iron and nitrogen elements. Then, it undergoes magnetic modification and is obtained through a hydrothermal reaction.

[0055] The preparation of the iron-nitrogen-doped ozone catalyst includes the following steps:

[0056] Step 11: Place 1g SBA-15, 1.25g sucrose, 0.14g H2SO4 and 5g H2O into a mixing container in sequence and stir well;

[0057] Step 12: Dry the solution from Step 11 at 80°C for 12 hours, and then carbonize it at 160°C for 6 hours;

[0058] Step 13: When the sample from Step 12 turns dark brown or black, add 0.4g sucrose, 0.2g urea, 0.15g ferrous chloride, 0.15g ferric chloride, 0.09g H2SO4, and 5 parts H2O to a mixing container in sequence.

[0059] Step 14: Dry the solution from step 13 at 80°C for 12 hours, then carbonize it at 160°C to obtain a black powder;

[0060] Step 15: Calcining the black powder obtained in Step 14 at 850°C in a nitrogen atmosphere for 1.5 hours, wherein the heating rate is 5°C / min. -1 ;

[0061] Step 16: Cool the material obtained in Step 15 to room temperature and repeatedly wash it with a strong alkaline solution to remove the silicon template;

[0062] The preparation of the iron-nitrogen-doped magnetic ozone catalyst includes the following steps:

[0063] Step 21: Disperse 2g of the iron-nitrogen-doped ozone catalyst in 120g of ethylene glycol solution and sonicate for 30min;

[0064] Step 22: Add 2g of magnetic main catalyst and 2g of magnetic co-catalyst to the solution obtained in step 21, and stir magnetically for 30min;

[0065] Step 23: Transfer the solution obtained in step 22 to a 250g stainless steel reactor with a polytetrafluoroethylene liner, react at 190℃ for 6 hours, and then allow it to cool naturally at room temperature.

[0066] Step 24: Wash the precipitate obtained in step 23 repeatedly with ultrapure water and ethanol several times, and finally dry it at 60°C for 12 hours. The resulting dark brown solid is iron-nitrogen doped magnetically ordered mesoporous carbon.

[0067] The strong alkaline solution mentioned in step 16 is a 10% (w / w) aqueous solution of sodium hydroxide or potassium hydroxide.

[0068] In step 22, the magnetic main catalyst is ferrous nitrate, and the magnetic co-catalyst is copper nitrate.

[0069] Example 3

[0070] This embodiment provides a method for preparing an iron-nitrogen-doped magnetic ozone catalyst. The iron-nitrogen-doped magnetic ozone catalyst uses ordered mesoporous carbon as a matrix, and obtains an iron-nitrogen-doped ozone catalyst by doping with iron and nitrogen elements. Then, it undergoes magnetic modification and is obtained through a hydrothermal reaction.

[0071] The preparation of the iron-nitrogen-doped ozone catalyst includes the following steps:

[0072] Place 1g SBA-15, 1.25g sucrose, 0.14g H2SO4 and 5g H2O into a mixing container in sequence and stir well;

[0073] Step 12: Dry the solution from step 11 at 100°C for 12 hours, and then carbonize it at 160°C for 6 hours;

[0074] Step 13: When the sample from Step 12 turns dark brown or black, add 0.4g sucrose, 0.2g urea, 0.2g ferrous chloride, 0.2g ferric chloride, 0.09g H2SO4, and 5g H2O to the mixing container in sequence.

[0075] Step 14: Dry the solution from step 13 at 100°C for 12 hours, then carbonize it at 160°C to obtain a black powder;

[0076] Step 15: Calcining the black powder obtained in Step 14 at 900°C in a nitrogen atmosphere for 2 hours, wherein the heating rate is 5°C·min. -1 ;

[0077] Step 16: Cool the material obtained in Step 15 to room temperature and repeatedly wash it with a strong alkaline solution to remove the silicon template;

[0078] The preparation of the iron-nitrogen-doped magnetic ozone catalyst includes the following steps:

[0079] Step 21: Disperse 3g of the iron-nitrogen-doped ozone catalyst in 200g of ethylene glycol solution and sonicate for 30min;

[0080] Step 22: Add 3g of magnetic main catalyst and 3g of magnetic co-catalyst to the solution obtained in step 21, and stir magnetically for 30min;

[0081] Step 23: Transfer the solution obtained in step 22 to a 250g stainless steel reactor with a polytetrafluoroethylene liner, react at 200℃ for 8 hours, and then allow it to cool naturally at room temperature.

[0082] Step 24: Wash the precipitate obtained in step 23 repeatedly with ultrapure water and ethanol several times, and finally dry it at 60°C for 12 hours. The resulting dark brown solid is iron-nitrogen doped magnetically ordered mesoporous carbon.

[0083] The strong alkaline solution mentioned in step 16 is a 12% (w / w) aqueous solution of sodium hydroxide or potassium hydroxide.

[0084] In step 22, the magnetic main catalyst is ferric nitrate, and the magnetic co-catalyst is nickel nitrate.

[0085] Example 4

[0086] like Figure 1As shown, this embodiment provides an ozone electrocatalytic coupling system using the above-mentioned catalyst, including a coupling catalytic reaction cylinder 3 and an inner circulation reaction cylinder 7. A water inlet 1 is provided at the bottom of one side of the coupling catalytic reaction cylinder, and the top of the other side is connected to the inner circulation reaction cylinder through a water pipe 6. Multiple anode plates 2 and cathode plates 5 are arranged vertically and alternately inside the coupling catalytic reaction cylinder. The cathode plate is an ozone aeration film plate. In this embodiment, the anode plate 2 is a titanium alloy plate, and the distance between the anode and the cathode is 2 cm. A spiral coil 9 is provided inside the inner circulation reaction cylinder.

[0087] The bottom of the internal circulation reaction cylinder is connected to the coupled catalytic reaction cylinder via a return pipe 11. A water outlet 10 is located at the bottom of the internal circulation reaction cylinder on the side opposite to the water pipe, and an air outlet line 8 is connected to the top of the internal circulation reaction cylinder. The surface of the spiral coil is coated with a hydrophobic coating using a siloxane reagent.

[0088] Ozone catalyst 4 is added to the coupled catalytic reaction vessel at a dosage of 0.2-2 g / L. The spiral coil is intermittently energized at a rate of 10%-40%. At room temperature, the residence time of wastewater in the ozone electrocatalytic coupling system is 10-120 min.

[0089] When treating wastewater, the wastewater flows in from the inlet, undergoes preliminary degradation in the coupled catalytic reaction chamber, and then flows into the inner circulation reaction chamber for further catalytic degradation. The purified water flows out from the outlet, and the catalyst flows back to the coupled reaction chamber through the return pipe, thus completing the circulation process.

[0090] The following is a further explanation of the system's operating status:

[0091] Wastewater from a pharmaceutical factory with a COD concentration of 851 mg / L was used. The wastewater and catalyst were mixed and entered the ozone electrocatalytic coupling system through the inlet. The catalyst dosage was 1.0 g / L. It first entered the coupling reaction chamber, where ozone was aerated through an ozone aeration membrane plate (the cathode plate also functioned as an aeration membrane plate). The O3 volumetric flow rate was 100–300 L / h. A constant current of 200 mA was applied between the cathode and anode plates. Ozone catalysis and electrocatalysis worked simultaneously to degrade pollutants. Subsequently, the catalyst and the partially degraded wastewater entered the inner circulation reaction chamber through a water pipe. The spiral coil 9 was intermittently energized at a energization rate of 20%. The catalyst is magnetic; after energization, the magnetic catalyst adsorbed onto the surface of the spiral coil. The catalyst accumulated under the electric field of the spiral coil 9. The surface of the spiral coil 9 was coated with a hydrophobic coating to increase the ozone concentration at the three-phase interface. Pollutants were further catalytically degraded under the action of ozone catalysis. After being powered on for a period of time, the power was turned off, and the catalyst fell to the bottom of the device and flowed back to the coupling reaction cylinder through the return pipe, thus achieving catalyst recycling. At room temperature, the wastewater residence time in the ozone electrocatalytic coupling system was 30 minutes. After the reaction, the COD content of the reactor effluent was 38 mg / L, and the COD removal rate was 95.5%, meeting the integrated wastewater discharge standard (GB8978). The first-level standard in 1996.

Claims

1. An ozone electrocatalytic coupling system employing an iron-nitrogen-doped magnetic ozone catalyst, characterized in that, It includes a coupled catalytic reaction cylinder and an internal circulation reaction cylinder. The bottom of one side of the coupled catalytic reaction cylinder is provided with a water inlet, and the top of the other side is connected to the internal circulation reaction cylinder through a water pipe. Multiple anode plates and cathode plates are arranged vertically and alternately inside the coupled catalytic reaction cylinder. The cathode plates are ozone aeration membrane plates. A spiral coil is provided inside the internal circulation reaction cylinder. The iron-nitrogen-doped magnetic ozone catalyst uses ordered mesoporous carbon as a matrix. By doping with iron and nitrogen elements, an iron-nitrogen-doped ozone catalyst is obtained. Then, it undergoes magnetic modification and is obtained through a hydrothermal reaction. The preparation of the iron-nitrogen-doped ozone catalyst includes the following steps: Step 11: Place 1 part SBA-15, 1.25 parts sucrose, 0.14 parts H2SO4 and 5 parts H2O into a mixing container in sequence and stir well; Step 12: Dry the solution from Step 11 at 60-100℃ for 12 hours, and then carbonize it at 160℃ for 6 hours; Step 13: When the sample from Step 12 turns dark brown or black, add 0.4 parts sucrose, 0.2 parts urea, 0.1-0.2 parts ferrous chloride and 0.1-0.2 parts ferric chloride, 0.09 parts H2SO4 and 5 parts H2O to the mixing container in sequence. Step 14: Dry the solution from Step 13 at 60-100℃ for 12 hours, then carbonize it at 160℃ to obtain a black powder; Step 15: Calcining the black powder obtained in Step 14 in a nitrogen atmosphere at 800~900℃ for 1-2 h, wherein the heating rate is 5℃·min. -1 ; Step 16: Cool the material obtained in Step 15 to room temperature and repeatedly wash it with a strong alkaline solution to remove the silicon template; The preparation of the iron-nitrogen-doped magnetic ozone catalyst includes the following steps: Step 21: Disperse 1-3 parts of the iron-nitrogen-doped ozone catalyst in 70-200 parts of ethylene glycol solution and sonicate for 30 min; Step 22: Add 1-3 parts of magnetic main catalyst and 1-3 parts of magnetic co-catalyst to the solution obtained in step 21, and stir magnetically for 30 minutes; Step 23: Transfer the solution obtained in Step 22 to a stainless steel reactor with a polytetrafluoroethylene liner containing 250 parts, react at 180-200 °C for 4-8 h, and allow to cool naturally at room temperature. Step 24: Wash the precipitate obtained in step 23 repeatedly with ultrapure water and ethanol several times, and finally dry it at 60°C for 12 hours. The resulting dark brown solid is iron-nitrogen doped magnetically ordered mesoporous carbon.

2. The ozone electrocatalytic coupling system using an iron-nitrogen-doped magnetic ozone catalyst according to claim 1, characterized in that, The strong alkaline solution mentioned in step 16 is an aqueous solution of sodium hydroxide or potassium hydroxide with a mass percentage of 8-12%.

3. The ozone electrocatalytic coupling system using an iron-nitrogen-doped magnetic ozone catalyst according to claim 1, characterized in that, The magnetic main catalyst in step 22 is selected from one or more of ferric citrate, ferrous nitrate, and ferric nitrate, and the magnetic co-catalyst is selected from one or more of potassium permanganate, copper nitrate, and nickel nitrate.

4. The ozone electrocatalytic coupling system using an iron-nitrogen-doped magnetic ozone catalyst according to claim 1, characterized in that, The bottom of the internal circulation reaction cylinder is connected to the coupled catalytic reaction cylinder via a reflux pipe.

5. The ozone electrocatalytic coupling system using an iron-nitrogen-doped magnetic ozone catalyst according to claim 4, characterized in that, The inner circulation reaction cylinder has a water outlet at its bottom on the side opposite to the water pipe, and an air outlet line is connected to the top of the inner circulation reaction cylinder.

6. The ozone electrocatalytic coupling system using an iron-nitrogen-doped magnetic ozone catalyst according to claim 5, characterized in that, The surface of the spiral coil is coated with a hydrophobic coating.

7. The ozone electrocatalytic coupling system using an iron-nitrogen-doped magnetic ozone catalyst according to claim 6, characterized in that, Ozone catalyst is added to the coupled catalytic reaction vessel at a dosage of 0.2-2 g / L.

8. The ozone electrocatalytic coupling system using an iron-nitrogen-doped magnetic ozone catalyst according to claim 7, characterized in that: The spiral coil is intermittently energized, with an energization rate of 10%-40%.

9. The ozone electrocatalytic coupling system using an iron-nitrogen-doped magnetic ozone catalyst according to claim 8, characterized in that, At room temperature, the residence time of wastewater in the ozone electrocatalytic coupling system is 10-120 min.

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