Preparation method of metal-doped carbon-nitrogen polymer-based self-cleaning film for in-situ oxidative decontamination and application device thereof

Abstract

The application discloses a preparation method of metal-doped carbon-nitrogen polymer and a preparation method and an application device of a self-cleaning film capable of realizing in-situ oxidative pollution reduction and taking the metal-doped carbon-nitrogen polymer as a base, and belongs to the technical field of water pollution treatment and relates to the field of membrane material technology. The metal-doped carbon-nitrogen polymer is prepared by adopting a hydrothermal forging and roasting technology and by means of structural substitution of carbon-nitrogen polymer through metal element doping, and in the catalytic process, the metal-doped carbon-nitrogen polymer is subjected to free radical and non-free radical cooperative reaction, and simultaneously has multi-functional oxidation activity of ozone catalytic oxidation, photocatalysis and ozone catalytic oxidation cooperative photocatalysis. The metal-doped polymer material is loaded into a pre-spinning solution composed of a polymer material, and a metal-doped carbon-nitrogen polymer-based self-cleaning film capable of realizing in-situ oxidative pollution reduction is prepared, the self-cleaning film can quickly respond to ozone and a lamp tube light source in dependence on the polymer material loaded on the film, generates hydroxyl radicals, superoxide radicals and singlet oxygen and the like, degrades pollutants adhered to the surface of the self-cleaning film, and thus realizes efficient in-situ self-cleaning of membrane pollution, and can effectively alleviate the problem of additional cost caused by shutdown of the petrochemical wastewater industry due to the membrane pollution problem.

Description

[0001] The application belongs to the technical field of water pollution treatment, mainly relates to the technical field of membrane materials, and particularly relates to a preparation method and a use device of a metal-doped carbon-nitrogen polymer-based self-cleaning membrane for in-situ oxidative pollution reduction in a biological membrane technology applied to water pollution treatment. BACKGROUND

[0002] Membrane separation technology is concerned in the field of water pollution treatment due to its simple operation, environmental protection and energy saving. However, in the long-term operation of the membrane, membrane pollution will reduce the permeability of the membrane, thereby reducing the flux and increasing the cost, which not only greatly weakens the separation efficiency of the membrane material on wastewater, but also causes irreversible damage to the membrane material. At present, the treatment methods for membrane pollution mainly exist in the static treatment of the membrane material, such as adding a coating on the surface of the membrane material. These methods can only alleviate the membrane pollution, and the problem of membrane pollution still exists after long-term operation, which requires the replacement of the material, and it is difficult to fundamentally solve the problem of membrane pollution.

[0003] The metal-doped carbon-nitrogen polymer prepared in the application can realize the synergistic reaction of free radicals and non-free radicals in the catalytic process, and has the multifunctional oxidation activity of ozone catalytic oxidation, photocatalysis and ozone catalytic oxidation synergistic photocatalysis. The metal-doped carbon-nitrogen polymer-based self-cleaning membrane continues the excellent performance of the powder polymer, can quickly respond to ozone and lamp light sources, generates hydroxyl radicals, superoxide radicals and singlet oxygen, and degrades the pollutants attached to the surface of the self-cleaning membrane, thereby realizing the efficient in-situ self-cleaning of the membrane pollution. The research and development of the in-situ oxidative pollution reduction self-cleaning membrane material can greatly reduce the attachment of pollutants on the membrane surface, prolong the service life of the membrane, reduce the water treatment cost, and promote the application and development of the membrane separation technology in the field of water pollution treatment. SUMMARY

[0004] The application aims to solve the challenge of membrane pollution in the field of water pollution treatment, and provides a preparation method and an application device of an in-situ oxidative pollution reduction self-cleaning membrane applied to a membrane process. The metal-modified carbon-nitrogen polymer-based self-cleaning membrane prepared by the method has excellent hydrophobic properties, ozone catalytic oxidation ability, photocatalytic ability and ozone catalytic oxidation synergistic photocatalytic multifunctional oxidation ability, and can generate hydroxyl radicals, superoxide radicals and singlet oxygen in the oxidation process, thereby realizing the in-situ mineralization of the pollutants attached to the surface of the self-cleaning membrane.

[0005] To achieve the above-mentioned purpose, the application first provides a metal-doped carbon-nitrogen polymer applied to water treatment technology and a preparation method of a metal-doped carbon-nitrogen polymer-based self-cleaning membrane for in-situ pollution reduction oxidation, and the specific steps are as follows:

[0006] S1, a certain amount of melamine and cyanuric acid is dissolved in high temperature water, after dissolution, the cyanuric acid solution is slowly dropped into the melamine solution, and a white suspension is obtained after stirring for a period of time;

[0007] S2, a certain amount of metal salt is added to the white suspension of step S1, stirred at a certain temperature for a period of time until mixed evenly, to obtain a mixed solution;

[0008] S3, the mixed solution of step S2 is centrifuged, washed with deionized water, and the white precipitate is transferred to the inner liner of the reaction kettle, a certain amount of N,N-dimethylacetamide is added, stirred at room temperature until mixed evenly, then transferred to the reaction kettle, and the metal doped carbon nitrogen polymer precursor is obtained by hydrothermal reaction;

[0009] S4, the polymer precursor of step S3 is freeze-dried and transferred to a tube furnace for calcination under nitrogen atmosphere, and the metal doped carbon nitrogen polymer powder is obtained after calcination.

[0010] S5, the high molecular material polyacrylonitrile (PAN) \ polyvinylpyrrole (PVP) and N,N-dimethylformamide (DMF) are mixed evenly, a certain amount of metal doped carbon nitrogen polymer powder of step S4 is added, stirred at a certain temperature until no particles are formed, and then pressurized to defoam to obtain a pre-spinning solution.

[0011] The pressurized defoaming is characterized by pouring the particle-free mixed solution into a round-bottom flask, connecting a vacuum filter, and increasing the pressure in the bottle to make the bubbles float and break to achieve the purpose of defoaming.

[0012] S6, the pre-spinning solution of step S5 is added to a needle tube container and fixed in an electrospinning device to prepare a nanofiber composite membrane.

[0013] S7, after hot pressing the in-situ oxidative pollution reduction metal doped carbon nitrogen polymer based self-cleaning film, immerse it in hot water for a period of time to remove PVP, and naturally dry to obtain an in-situ oxidative pollution reduction self-cleaning film with excellent self-cleaning ability.

[0014] S8, the metal doped carbon nitrogen polymer based self-cleaning film prepared is placed in a transparent photocatalytic ozone catalytic device, and its pollutant degradation performance is tested under the synergistic action of ozone and light;

[0015] The photocatalytic ozone catalytic device is a transparent cup-shaped container, the lower end is provided with a cooling circulating water system to ensure constant temperature during the experiment, the upper end is provided with an air inlet and an air outlet connected with an ozone generator, the top is sealed by a transparent quartz glass sheet, and a xenon lamp is located above the device.

[0016] Preferably, the mass ratio of melamine to cyanuric acid is 0.5-1:1 (mol:mol), the high-temperature water temperature is 80-90℃, the stirring temperature of melamine and cyanuric acid is 60-80℃, and the stirring time is 1-3h;

[0017] Preferably, the metal salt (the desired metal ions are provided by manganese chloride, iron chloride, chromium chloride, nickel chloride) is added in an amount of 10-40mg, the stirring temperature after adding the metal salt is 65-85℃, and the stirring time is 1-2h;

[0018] Preferably, the deionized water washing is performed 2-4 times, the reaction temperature of the hydrothermal reaction condition is 160-200℃, and the reaction time is 7-9h;

[0019] Preferably, the tube furnace calcination condition is calcination at 520℃ for 4-6h, and the temperature rising speed is 2-2.5℃ / min;

[0020] Preferably, the metal-doped carbon-nitrogen nanotube is added in an amount of 0.8-1.5g, the stirring temperature is 60-80℃, and the stirring time is 16-24h;

[0021] Preferably, the high-temperature water temperature for soaking the self-cleaning membrane is 60-80℃, and the soaking time is 8-12h.

[0022] Preferably, the pollutant is one of the typical pollutants in petrochemical wastewater, and the pollutant used in the experiment is p-nitrophenol, and the pollutant concentration is 10-50mg / L.

[0023] The application further provides a device for using the in-situ oxidation self-cleaning membrane and a method for using the same, and the specific content is as follows:

[0024] The device for the in-situ oxidation self-cleaning membrane, characterized in that, mainly comprises: (1) a box-shaped shell (2) a membrane piece clamping groove (3) an air inlet (4) a sewage inlet (5) five groups of membrane pieces (6) a mixed solution channel (7) a clean water outlet (8) a ring-shaped lamp tube (9) a central transparent pipeline

[0025] Preferably, the (5) five groups of membrane pieces use the main membrane material of the in-situ oxidation self-cleaning membrane with the oil-water separation performance and excellent self-cleaning ability according to claim 1; the (3) air inlet uses ozone; and the (8) ring-shaped lamp tube can use one or more of an ultraviolet lamp, a mercury lamp, an LED lamp, and a xenon lamp.

[0026] The in-situ oxidation pollution reduction self-cleaning membrane device has the oil-water separation performance and excellent self-cleaning ability, characterized in that sewage enters a mixed liquid channel (6) through a sewage inlet pipe (4), ozone also enters the central pipeline through a gas inlet (3), the sewage and the ozone are mixed for the first time, a ring-shaped lamp tube (8) is opened, under the light condition, the sewage transmits through the diaphragm (5) to realize the ozone catalysis, the photocatalysis and the ozone catalytic oxidation synergistic photocatalysis performance of the self-cleaning membrane, the pollutants on the membrane surface generate the response, the free radicals and the non-free radicals are generated to in-situ mineralize the pollutants, and the attachment of the pollutants on the membrane surface can be reduced; the clean water flows out from the outlet after being filtered through the five groups of diaphragms (5).

[0027] Compared with the prior art, the advantages of the application are that:

[0028] 1、The hydrothermal calcination technology is adopted, the carbon-nitrogen polymer is structurally replaced by metal element doping and non-metal amino modification, the metal-doped carbon-nitrogen polymer prepared has the synergistic reaction of free radicals and non-free radicals in the catalysis process, and has the multifunctional oxidation activity of ozone catalytic oxidation, photocatalysis and ozone catalytic oxidation synergistic photocatalysis. Meanwhile, the powder material is immobilized by using the electrospinning technology, the defect that the powder catalytic material is difficult to recover in the water pollution treatment technology is avoided, and the membrane can produce surface stimulation response to ozone and light, promote the generation of active oxygen on the membrane surface, and accelerate the mineralization rate of pollutants.

[0029] 2、Compared with the existing membrane pollution treatment process, the nanofiber structure in the in-situ oxidation self-cleaning membrane is compact and has good stability, has excellent risk resistance in the membrane separation technology, the self-cleaning membrane can respond to ozone and light at the same time, the treatment intensity can be adjusted by adjusting the ozone concentration, light intensity and the like in the pollution treatment process, and the surface stimulation response source can be flexibly adjusted according to the water quality and the risk of membrane damage, thereby reducing the self-cleaning cost. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a schematic diagram of the in-situ oxidation pollution reduction self-cleaning membrane device;

[0031] Figure 2 It is a surface scanning electron microscope graph of the in-situ oxidation pollution reduction self-cleaning membrane of Example 1;

[0032] Figure 3 It is a real object graph of the in-situ oxidation pollution reduction self-cleaning membrane prepared in Example 1;

[0033] Figure 4 It is a performance graph of the in-situ oxidation pollution reduction self-cleaning membrane prepared in Example 1 in degrading 30 mg / L p-nitrophenol pseudo-wastewater. DETAILED DESCRIPTION

[0034] The application will be further described below with reference to specific examples. The described examples are only some of the embodiments of the application, not all the embodiments. The following examples are used to illustrate the technical solutions of the application, but not to limit the protection scope of the application. Those skilled in the art should understand that all other embodiments obtained without creative labor fall within the protection scope of the application.

[0035] The embodiment technical solutions of the application application are as follows to solve the above problems:

[0036] The application provides a metal-modified carbon-nitrogen polymer and a preparation method of a metal-modified carbon-nitrogen polymer-based self-cleaning film. The hydrothermal sintering technology is adopted to modify the carbon-nitrogen polymer by using metal elements and non-metal amino groups to replace the structure of the carbon-nitrogen polymer. The metal-doped carbon-nitrogen polymer prepared by the method has the functions of radical and non-radical synergistic reaction in the catalytic process, ozone catalytic oxidation, photocatalysis, and ozone catalytic oxidation synergistic photocatalysis multifunctional oxidation activity. The electrospinning technology is used to realize the immobilization of the powder polymer material, and the self-cleaning film prepared by the method can produce surface stimulus response to ozone and light, promote the generation of active oxygen on the film surface, and accelerate the mineralization rate of pollutants.

[0037] The application also provides an application device of an in-situ oxidative pollution reduction self-cleaning film. The sewage passing through the device can produce response on the film surface to generate free radicals and non-radicals for in-situ mineralization of pollutants. In the pollution treatment process, the treatment intensity can be adjusted by adjusting the ozone concentration, light intensity and other conditions, and the surface stimulus response source can be flexibly adjusted according to the water quality and the risk of film damage, thereby reducing the self-cleaning cost.

[0038] Example 1

[0039] In an embodiment of the application, a preparation method of a metal-doped carbon-nitrogen polymer and a metal-doped carbon-nitrogen polymer-based in-situ oxidative self-cleaning film is provided, and the preparation method is as follows:

[0040] A certain amount of melamine and cyanuric acid (1:1 moL) are quickly dissolved in hot water at 90°C, after dissolution, slowly drop the cyanuric acid solution into the melamine solution at 90°C, after stirring at 80°C for 1h, add 25mg of anhydrous manganese chloride to the uniformly mixed white suspension, continue to stir at 80°C for 1h until the mixture is uniform, transfer the obtained suspension to the inner liner of the reaction kettle after centrifugation and washing with deionized water for the third time, add 2ml of N,N-dimethylacetamide, stir uniformly, then transfer the mixture to the reaction kettle, hydrothermal reaction at 180°C for 8h to obtain a metal-doped carbon-nitrogen polymer powder precursor, after freeze-drying, calcine at 520°C under nitrogen atmosphere in a tube furnace for 4h (2°C / min), obtain modified carbon nitride powder, disperse 1.2g of PAN, 0.8g of PVP, and 1g of the prepared metal-doped carbon-nitrogen polymer powder uniformly into 10g of DMF solvent, stir uniformly, and then defoam to obtain a pre-spinning solution.

[0041] The pre-spinning solution is added to a needle tube container and fixed in an electrospinning device, and a nanofiber membrane is obtained by electrospinning, then hot-pressed with a cold laminator, and then soaked in 80°C water for 8h to remove PVP to construct a porous structure, and then naturally air-dried to obtain an in-situ oxidation pollution-reducing self-cleaning membrane.

[0042] Example 2

[0043] In an embodiment of the present application, a metal-doped carbon-nitrogen polymer and a preparation method of a metal-doped carbon-nitrogen polymer-based in-situ oxidation self-cleaning membrane are provided, and the preparation method is as follows:

[0044] A certain amount of melamine and cyanuric acid (1:1 moL) are quickly dissolved in hot water at 90°C, after dissolution, slowly drop the cyanuric acid solution into the melamine solution at 90°C, after stirring at 80°C for 1h, add 25mg of anhydrous manganese chloride to the uniformly mixed white suspension, continue to stir at 80°C for 1h until the mixture is uniform, transfer the obtained suspension to the inner liner of the reaction kettle after centrifugation and washing with deionized water for the third time, add 2ml of N,N-dimethylacetamide, stir uniformly, then transfer the mixture to the reaction kettle, hydrothermal reaction at 180°C for 8h to obtain a metal-doped carbon-nitrogen polymer powder precursor, after freeze-drying, calcine at 520°C under nitrogen atmosphere in a tube furnace for 4h (2°C / min), obtain modified carbon nitride powder, disperse 1.2g of PAN, 0.8g of PVP, and 1g of the prepared metal-doped carbon-nitrogen polymer powder uniformly into 10g of DMF solvent, stir uniformly, and then defoam to obtain a pre-spinning solution.

[0045] The pre-spinning solution is added to a needle tube container and fixed in an electrospinning device, and a nanofiber membrane is obtained by electrospinning, then hot-pressed with a cold laminator, and then soaked in 80°C water for 8h to remove PVP to construct a porous structure, and then naturally air-dried to obtain an in-situ oxidation pollution-reducing self-cleaning membrane.

[0046] Example 3

[0047] One embodiment of the present application provides a preparation method of a nanofiber membrane, and the preparation method is as follows:

[0048] 1.2 g of PAN and 0.8 g of PVP are uniformly dispersed into 10 g of DMF solvent, defoaming after uniform stirring to obtain a pre-spinning solution.

[0049] The pre-spinning solution is added into a needle tube container and fixed in an electrospinning device, and after obtaining a nanofiber membrane by electrospinning, hot pressing is performed by using a cold laminating machine, then the nanofiber membrane is soaked in 80℃ water for 8 h to remove PVP to construct a porous structure, and after natural air drying, the nanofiber membrane is obtained.

[0050] Example 4

[0051] One embodiment of the present application provides a preparation method of a metal-doped carbon-nitrogen polymer-based in-situ oxidation self-cleaning membrane, and the preparation method is as follows:

[0052] 1 g of metal-doped carbon-nitrogen polymer powder is ultrasonically dispersed in 10 mL of DMF, mixed with 0.9 g of polyacrylonitrile (PAN), stirred at 60℃ for 12 h to obtain a pre-spinning solution. The pre-spinning solution is added into a needle tube container and fixed in an electrospinning device, and after obtaining a nanofiber membrane by electrospinning, hot pressing is performed by using a cold laminating machine, then the nanofiber membrane is soaked in 80℃ water for 8 h to remove PVP to construct a porous structure, and after natural air drying, the in-situ oxidation and pollution reduction self-cleaning membrane is obtained.

[0053] Example 5

[0054] The present embodiment provides an application device of an in-situ oxidation and pollution reduction self-cleaning membrane, which specifically comprises the following parts:

[0055] (1) Box shell (2) Membrane clamping groove (3) Gas inlet (4) Sewage inlet (5) Five groups of membranes (6) Mixed liquid channel (7) Clean water outlet (8) Ring-shaped lamp tube (9) Central transparent pipeline; the five groups of membranes (5) use the in-situ oxidation and pollution reduction self-cleaning membrane of the main membrane material; the gas inlet (3) is one or more of ozone, oxygen and air; the ring-shaped lamp tube (8) can use one or more of ultraviolet lamp, mercury lamp, LED lamp and xenon lamp tube.

[0056] Method for use: sewage enters the mixed liquid channel (6) through the sewage inlet pipe (4), and ozone also enters the central pipeline through the gas inlet (3), so that the sewage and ozone are mixed for the first time, the ring-shaped lamp tube (8) is turned on, and under the light condition, the sewage passes through the membranes (5) to realize ozone catalysis, photocatalysis and the synergistic performance of ozone catalytic oxidation and photocatalysis of the self-cleaning membrane, pollutants on the membrane surface generate response to produce free radicals and non-free radicals for in-situ mineralization of the pollutants, and the attachment of the pollutants on the membrane surface is reduced; after filtration through the five groups of membranes (5), clean water flows out from the outlet.

Claims

1. A method for preparing an in-situ oxidative decontamination metal-doped carbon-nitrogen polymer-based self-cleaning membrane, characterized in that, Includes the following steps: Step S1: Dissolve an appropriate amount of melamine and cyanuric acid in hot water quickly. After dissolving, slowly add the cyanuric acid solution to the melamine solution and stir for a period of time to obtain a white suspension. Step S2: Add an appropriate amount of metal salt to the white suspension from step S1, and stir for a period of time under a certain temperature until the mixture is homogeneous to obtain a mixed solution; the metal salt is composed of one or more of manganese chloride, ferric chloride, chromium chloride, and nickel chloride; Step S3: After centrifuging the mixture from step S2, wash it with deionized water, transfer the white precipitate to the liner of the reactor, add an appropriate amount of N,N-dimethylacetamide, stir at room temperature until the mixture is homogeneous, and then transfer it to the reactor. The metal-doped carbon-nitrogen polymer precursor is obtained through hydrothermal reaction. Step S4: After freeze-drying the polymer precursor described in step S3, transfer it to a tube furnace and calcine it under a nitrogen atmosphere. After calcineation, metal-doped carbon-nitrogen polymer powder is obtained. Step S5: Polyacrylonitrile, polyvinylpyrrolidone and N,N-dimethylformamide are mixed evenly, and an appropriate amount of the metal-doped carbon-nitrogen polymer powder described in step S4 is added to it. After stirring at a certain temperature until there are no particles, pressure is applied to defoam and obtain a pre-spinning solution. The pressurized defoaming method is characterized by pouring a particulate-free mixture into a round-bottom flask, connecting it to a vacuum filter, and achieving defoaming by increasing the pressure inside the flask so that the bubbles rise and burst. Step S6: Add the pre-spinning solution from step S5 into a syringe container and fix it in an electrospinning device to prepare a metal-doped carbon-nitrogen polymer-based self-cleaning membrane for in-situ oxidation and decontamination of the crude product. Step S7: After hot pressing the crude product of the metal-doped carbon nitride polymer-based self-cleaning membrane with in-situ oxidation and decontamination, soak it in hot water for a period of time to remove PVP, and then air dry it to obtain the metal-doped carbon nitride polymer-based self-cleaning membrane with in-situ oxidation and decontamination. Step S8: The prepared in-situ oxidation and decontamination metal-doped carbon and nitrogen polymer-based self-cleaning membrane is placed in a transparent photocatalytic synergistic ozone catalytic device, and its pollutant degradation performance is tested under the synergistic effect of ozone and light. The photocatalytic synergistic ozone catalysis device is a transparent cup-shaped container with a cooling circulating water system at the bottom to ensure a constant temperature during the experiment. The top is equipped with an air inlet and an air outlet, which are connected to the ozone generator. The top is sealed with a transparent quartz glass sheet, and a xenon lamp is located above the device.

2. The preparation method according to claim 1, characterized in that: In step S1, the mass ratio of melamine to cyanuric acid is 0.5 to 1:1, the temperature of the high-temperature water is 80 to 90°C, the stirring temperature of melamine and cyanuric acid is 60 to 80°C, and the stirring time is 1 to 3 hours. In step S2, the amount of metal salt added is 10mg to 40mg, the stirring temperature after adding the metal salt is 65 to 85℃, and the stirring time is 1 to 2h. In step S3, the number of times the deionized water is washed is 2 to 4, the reaction temperature under hydrothermal reaction conditions is 160 to 200°C, and the reaction time is 7 to 9 hours. In step S4, the calcination conditions are 520℃ for 4-6 hours, and the heating rate is 2-2.5℃ / min. In step S5, the amount of metal-doped carbon-nitrogen polymer powder added is 0.8–1.5 g, the stirring temperature is 60–80 °C, and the stirring time is 16–24 h. In step S7, the hot water temperature is 60-80℃, and the soaking time is 8-12 hours. The pollutant in step S8 is one of the pollutants in petrochemical wastewater, namely p-nitrophenol, with a concentration of 10-50 mg / L.

3. A device for in-situ oxidation and decontamination of a metal-doped carbon-nitrogen polymer-based self-cleaning membrane using the preparation method described in claim 1, characterized in that, Mainly includes: box type The components include: housing (1), diaphragm slot (2), air inlet (3), sewage inlet (4), diaphragm (5), mixed liquid channel (6), clear water outlet (7), ring lamp tube (8), and central transparent pipe (9); the diaphragm (5) consists of five sets. The membrane (5) uses a metal-doped carbon-nitrogen polymer-based self-cleaning membrane with in-situ oxidation and decontamination prepared by the preparation method described in claim 1 as the main membrane material; the air inlet (3) is for ozone; and the annular lamp (8) is a xenon lamp.

4. A metal-doped carbon-nitrogen polymer-based self-cleaning membrane device for in-situ oxidation and decontamination as described in claim 3, characterized in that... Wastewater enters the mixed liquid channel (6) through the wastewater inlet (4), while ozone enters the central pipe through the air inlet (3). Wastewater and ozone are mixed for the first time. The ring lamp tube (8) is turned on. Under the illumination, the wastewater passes through the membrane (5) to achieve the ozone catalysis, photocatalysis and ozone catalytic oxidation synergistic photocatalytic performance of the self-cleaning membrane. Pollutants respond on the membrane surface, generating free radicals and non-free radicals to mineralize the pollutants in situ and reduce the adhesion of pollutants on the membrane surface. After filtration through the five sets of membranes (5), the clean water flows out from the outlet.

5. A metal-doped carbon-nitrogen polymer-based self-cleaning membrane device for in-situ oxidation and decontamination as described in any one of claims 3-4, wherein the membrane (5) has multifunctional catalytic activity of ozone catalytic oxidation, photocatalysis, and ozone catalytic oxidation synergistic photocatalysis; the annular lamp (8) can provide sufficient light source during membrane operation, so that the photocatalytic activity of the membrane can mineralize pollutants under optimal conditions, and promote the realization of online in-situ self-cleaning.

6. A metal-doped carbon-nitrogen polymer-based self-cleaning membrane for in-situ oxidation and decontamination prepared by the preparation method according to any one of claims 1-2.

7. The application of a metal-doped carbon-nitrogen polymer-based self-cleaning membrane device for in-situ oxidation and decontamination as described in any one of claims 3-4 in the field of membrane technology.

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