Preparation method of carbon nanotube blended conductive film and method for controlling algae source pollution by coupling electro-activated peracetic acid

Abstract

The invention belongs to the technical field of pollution control of membrane-method water treatment, and particularly relates to a preparation method of a carbon nanotube blended conductive membrane and a method for controlling algae source pollution by coupling electro-activated peracetic acid with the carbon nanotube blended conductive membrane. The preparation method comprises the following steps: dispersing oxygen functional group modified carbon nanotubes, polyvinylpyrrolidone and polyethersulfone in an organic solvent to prepare a membrane casting solution, preparing a basement membrane through a flat membrane scraping process, and then modifying the basement membrane with conductive polyaniline-sodium polystyrenesulfonate through an in-situ crosslinking method to prepare the carbon nanotube blended conductive membrane. In a coupled membrane filtration system, peracetic acid is used as an oxidizing agent, voltage is applied to a membrane to perform in-situ activation on peracetic acid to generate an active species with oxidizing capacity, an algae source pollutant solution is used as a target water body, and membrane pollution caused by algae source pollutants is efficiently relieved through the filtration system.

Description

Technical Field

[0001] The invention belongs to the technical field of pollution control of membrane water treatment, and specifically relates to a method for preparing a carbon nanotube blended conductive membrane and a method for coupling the membrane with electrically activated peracetic acid to control algae source pollution. Background Art

[0002] Algal pollution is a serious problem facing the global water environment. It is mainly caused by eutrophication, leading to algal blooms, water hypoxia and the proliferation of harmful algae. This not only destroys the aquatic ecosystem, but also has a significant impact on drinking water safety, fishery production and tourism. Traditional methods for controlling algal pollution include chemical agent addition, physical precipitation, biological control, etc., but these methods may have disadvantages such as secondary pollution, unstable effects or high costs. In recent years, membrane separation technology has become one of the important means of water treatment due to its advantages such as high efficiency, energy saving and environmental protection. In particular, ultrafiltration membranes perform well in removing suspended matter, colloids and microorganisms. However, when treating algal polluted water, traditional ultrafiltration membranes are prone to membrane fouling, resulting in decreased flux and increased operating costs. To solve this problem, researchers have tried to improve the anti-pollution performance and separation efficiency of membranes through material modification and process optimization. Carbon nanotubes are widely used in the preparation of new high-performance membrane materials to improve membrane performance due to their excellent conductivity, mechanical strength and chemical stability. At the same time, peracetic acid, as an efficient and environmentally friendly oxidant, can generate active species with strong oxidizing ability and is widely used in the degradation of organic pollutants. Therefore, combining carbon nanotubes with peracetic acid and using electroactivation technology is expected to achieve efficient control of algae pollution. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing a carbon nanotube blended conductive membrane and a method for coupling the electro-activated peracetic acid to effectively control algae pollution. The method introduces carbon nanotubes modified with oxygen functional groups in the preparation of the separation membrane to enhance the conductivity and electro-oxidation activity of the membrane, and combines the electro-activated peracetic acid to generate highly efficient oxidation species, thereby achieving efficient removal of algae pollutants. With the conductive membrane as the working electrode, voltage is applied during the separation process to achieve efficient removal of pollutants and containment of membrane pollution.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] In one aspect, the present invention provides a method for preparing a carbon nanotube blended conductive film, comprising the following steps:

[0006] (1) Oxygen functional group modification of carbon nanotubes

[0007] The carbon nanotubes are evenly distributed in a crystallization dish and placed in an oxygen plasma generator for treatment to obtain carbon nanotubes modified with oxygen functional groups;

[0008] (2) Preparation of casting solution

[0009] Adding oxygen functional group-modified carbon nanotubes, polyethersulfone and polyvinyl pyrrolidone to a solvent, stirring evenly at room temperature for 18 to 36 hours to obtain a dispersion, then adding polyethylene glycol at a constant temperature of 50 to 80° C., stirring until completely dissolved, and then standing to degas, to obtain a casting solution;

[0010] (3) Preparation of basement membrane

[0011] The casting liquid is scraped onto a glass plate, and the glass plate coated with the casting liquid is immersed in a coagulation bath for 30 minutes to complete the curing of the base film;

[0012] (4) In situ cross-linking of basement membrane

[0013] The cured base film is transferred from the coagulation bath to deionized water for washing, and the base film is placed in a mixture of aniline and sodium poly(p-styrene sulfonate) and soaked at 4°C for 20 to 30 minutes. The base film is then taken out and immersed in an ammonium persulfate solution to react for 5 to 10 minutes. The base film is then placed at 4°C to react for 3 to 6 hours. The base film is then taken out and placed in an acidic solution of glutaraldehyde for cross-linking, and then washed with pure water and immersed in pure water to obtain a carbon nanotube blended conductive film.

[0014] In the above technical solution, further, in step (1), the oxygen content of the carbon nanotubes modified with oxygen functional groups is 0.1 to 0.5 wt %;

[0015] The carbon nanotubes are multi-walled carbon nanotubes or multi-walled array carbon nanotubes, and the diameter of the carbon nanotubes is 10 to 25 nm;

[0016] The plasma radio frequency power is 50-100 W, the radio frequency frequency is 13.56 MHz, the gas pressure in the chamber is 50-100 Pa, and the processing time is 10-60 s.

[0017] In the above technical solution, further, in step (2), the solvent is one or a mixture of two of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide;

[0018] The molecular weight of the polyethylene glycol is 50,000 to 300,000.

[0019] In the above technical solution, further, in step (2), the mass fraction of the solute in the casting solution is 30-60%.

[0020] In the above technical solution, further, in step (2), in the casting solution, the mass ratio of oxygen functional group-modified carbon nanotubes, polyethersulfone, polyvinyl pyrrolidone, and polyethylene glycol is (2-3):3:1:1.

[0021] In the above technical scheme, further, in step (3), the scraping gap of the flat scraper is 300-500 μm, and the scraping is carried out at a constant speed of 5-10 cm / s; the coagulation bath is a 10%-20% mass fraction N,N-dimethylacetamide aqueous solution, and the temperature of the coagulation bath is 20-25°C.

[0022] In the above technical solution, further, in step (4), the basement membrane is soaked and washed at a constant temperature of 40 to 60° C. for 0.5 to 1 h;

[0023] The cross-linking time of the glutaraldehyde is 30 to 60 minutes.

[0024] In the above technical solution, further, in step (4), in the mixed solution of aniline and sodium poly(p-styrene sulfonate), the mass ratio of aniline to sodium poly(p-styrene sulfonate) is 1:1, and the concentration of aniline is 0.5-2.0wt%.

[0025] Another aspect of the present invention provides a carbon nanotube blended conductive film obtained by the above preparation method.

[0026] The present invention also provides a method for controlling algae pollution by coupling carbon nanotube blended conductive membrane with electrically activated peracetic acid. The carbon nanotube blended conductive membrane is used as a membrane electrode. During the treatment of algae polluted water, peracetic acid is added to the influent at a concentration of 0.5 to 5 mg / L. A voltage of 0.5 to 3 V is applied to the membrane. The filtration form is constant pressure cross-flow filtration, the filtration pressure is 0.5 to 2.0 bar, and the cross-flow velocity is 0.05 to 0.1 m / s.

[0027] In the above technical solution, further, the method specifically comprises the following steps:

[0028] a. Encapsulate the carbon nanotube blended conductive film in a flat membrane module, with the membrane serving as the working electrode. A counter electrode metal mesh of the same area is arranged opposite the membrane inside the module. The distance between the metal mesh and the flat membrane is 8 mm. Lead wires from the metal mesh, connect the metal electrode clip and the wires to the conductive film, and connect the two-stage wires to an external DC regulated power supply;

[0029] b. Add 0.5-10 mg / L of peracetic acid to the algae-contaminated water, and apply voltage to the conductive membrane through a DC stabilized power supply to filter the water. The filtering method is cross-flow filtration, and the filtering pressure of the membrane assembly is adjusted to be constant at 0.5-2 bar.

[0030] c. When the operating flux drops by 50%, stop filtration, close the cross-flow valve, open the inlet valve and outlet valve, apply pressure water flow from one side of the outlet valve to perform backwashing to remove membrane contamination.

[0031] In the above technical solution, further, in step a, the metal mesh is a titanium mesh, a copper mesh or a stainless steel mesh; the lead wire is a titanium wire, a copper wire or a stainless steel wire; the electrode clamp is a titanium electrode clamp, a copper electrode clamp or a stainless steel electrode clamp.

[0032] In the above technical solution, further, in step b, the applied voltage is 0.5 to 3.0 V, preferably 2.0 to 2.5 V, the membrane is the cathode, and the metal mesh is the anode.

[0033] In the above technical solution, further, in step c, during backwashing, the backwashing pressure is 0.5 to 1.0 bar, and the backwashing time is 5 to 15 minutes.

[0034] The present invention prepares an electroactive separation membrane by modifying the oxygen functional groups of carbon nanotubes and adopting a blending and cross-linking method, and constructs a membrane separation layer with excellent peracetic acid electroactivation characteristics. Under the condition of an applied voltage, peracetic acid can be activated to produce a large number of active free radical species, which can effectively oxidize organic matter in algae-contaminated water and slow down the accumulation of pollutants on the membrane surface and in the membrane pores.

[0035] The present invention proposes a method based on carbon nanotube blended conductive membrane coupled with electro-activated peracetic acid for efficient control of algae pollution. Compared with traditional water treatment technologies, the present invention has the following significant advantages and beneficial effects:

[0036] 1. Efficient removal of algae-derived pollutants: By electro-activating peracetic acid to generate highly active oxidizing species, it can completely degrade harmful substances such as microcystins in the water, with a removal rate of up to 100%. This effectively solves the problem that traditional drinking water treatment processes are difficult to remove algae toxins, and ensures the safety of drinking water.

[0037] 2. Significantly reduce the accumulation rate of membrane fouling: The carbon nanotube blended conductive membrane has excellent conductivity and anti-fouling properties. During the filtration process, the accumulation rate of membrane fouling is reduced by more than 90%, and both reversible and irreversible membrane fouling are effectively alleviated. This extends the service life of the membrane and reduces maintenance and replacement costs.

[0038] 3. Enhance the mechanical and chemical stability of the membrane: The addition of carbon nanotubes improves the mechanical strength and chemical corrosion resistance of the membrane, making it suitable for various complex water treatment environments. This overcomes the defect of the traditional polyethersulfone membrane's insufficient stability in a strong oxidizing environment.

[0039] 4. Low energy consumption for water production: The electrical activation of peracetic acid can be achieved at a relatively low voltage (0.5-3V), and the filtration resistance is reduced. Compared with other advanced oxidation technologies, such as ozone oxidation or ultraviolet photocatalysis, the energy consumption is low.

[0040] 5. Environmentally friendly, no secondary pollution: Peracetic acid decomposes into water, oxygen and acetic acid after the reaction, which is environmentally friendly. The electroactivation process does not produce harmful by-products, avoiding the risk of secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is an electronic photograph of the casting solution prepared in Example 1;

[0042] Figure 2 This is an electronic photograph of the carbon nanotube blended conductive film prepared in Example 1;

[0043] Figure 3 The process flow chart of the preparation method of the carbon nanotube blended conductive film of the present invention;

[0044] Figure 4 This is a diagram showing the anti-membrane fouling effect of the carbon nanotube blended conductive membrane of Example 1 coupled with electrically activated peracetic acid in filtering an algae extracellular polymer solution;

[0045] Figure 5 This is a diagram showing the removal effect of microcystin on the carbon nanotube blended conductive membrane of Example 1 after coupling with electrically activated peracetic acid when filtering an algal extracellular polymer solution. DETAILED DESCRIPTION

[0046] In order to better understand the technical solution of the present invention, the present invention is further described in detail by three embodiments below. However, the following embodiments are only simple examples of the present invention and are not limited to the following embodiments.

[0047] Unless otherwise specified, the materials used in the embodiments of the present invention can be obtained through commercial channels or prepared according to conventional methods well known to those skilled in the art.

[0048] Example 1

[0049] The preparation method of the carbon nanotube blended conductive film specifically comprises the following steps:

[0050] (1) Oxygen functional group modification of carbon nanotubes

[0051] The carbon nanotubes were evenly distributed in a crystallization dish, and placed in an oxygen plasma generator, with a plasma radio frequency power of 50 W, a radio frequency frequency of 13.56 MHz, a chamber pressure of 60 Pa, a modification time of 20 s, and repeated 3 times to obtain oxygen functional group-modified carbon nanotubes, wherein the oxygen content was 0.2 wt%;

[0052] (2) Preparation of casting solution

[0053] According to the mass ratio of carbon nanotubes modified with oxygen functional groups, polyethersulfone, polyvinyl pyrrolidone and polyethylene glycol being 2:3:1:1, carbon nanotubes modified with oxygen functional groups, polyethersulfone and polyvinyl pyrrolidone were added to N,N-dimethylacetamide, and stirred evenly at room temperature for 24 hours to obtain a dispersion liquid, and then polyethylene glycol was added at a constant temperature of 55°C, stirred until completely dissolved, and then allowed to stand for 24 hours for degassing to obtain a casting solution. The electron photograph of the casting solution is shown in FIG. Figure 1 As shown;

[0054] (3) Preparation of basement membrane

[0055] The film scraping gap of the flat film scraper is fixed to 300 μm, 20 mL of casting liquid is poured into one end of the glass plate of the film scraper, and the casting liquid is evenly scraped on the glass plate with the film scraper at a constant speed of 5 cm / s, and the glass film coated with the casting liquid is immersed in a coagulation bath of a mass fraction of N,N-dimethylacetamide aqueous solution for 30 minutes to complete the curing of the base film;

[0056] (4) In situ cross-linking of basement membrane

[0057] The cured base membrane was transferred from the coagulation bath to deionized water, and soaked at a constant temperature of 60°C for 0.5h, during which the water was changed 3 times to remove the residual solvent and pore-forming agent polyethylene glycol; the base membrane was placed in a mixed solution of aniline and sodium polystyrene sulfonate (PSS) (the mass ratio of aniline to PSS was 1:1, and the aniline concentration was 1.0wt%), and soaked at 4°C for 30min. Then, it was taken out and immersed in 0.16mol / L ammonium persulfate solution again, reacted for 5min, and then placed at 4°C for 6h. Subsequently, it was taken out and entered into an acidic solution of glutaraldehyde (the solvent was hydrochloric acid, and the concentration of glutaraldehyde was 2wt%) for cross-linking for 30min, and then washed with pure water and soaked in pure water.

[0058] The molecular weight cut-off of the conductive membrane prepared in Example 1 is 150 kDa, and the conductivity is 16 S / m. Figure 2 This is a digital photo of the separation membrane, and the surface is intact and has no defects.

[0059] Example 2

[0060] The preparation method of the carbon nanotube blended conductive film specifically comprises the following steps:

[0061] (1) Oxygen functional group modification of carbon nanotubes

[0062] The carbon nanotubes were evenly distributed in a crystallization dish, and placed in an oxygen plasma generator, with a plasma radio frequency power of 100 W, a radio frequency frequency of 13.56 MHz, a chamber pressure of 100 Pa, a modification time of 10 s, and repeated 3 times to obtain oxygen functional group-modified carbon nanotubes, wherein the oxygen content was 0.2 wt%;

[0063] (2) Preparation of casting solution

[0064] According to the mass ratio of carbon nanotubes modified with oxygen functional groups, polyethersulfone, polyvinyl pyrrolidone and polyethylene glycol being 2:3:1:1, carbon nanotubes modified with oxygen functional groups, polyethersulfone and polyvinyl pyrrolidone were added to N,N-dimethylacetamide, and stirred evenly at room temperature for 18 hours to obtain a dispersion liquid, and then polyethylene glycol was added at a constant temperature of 70°C, stirred until completely dissolved, and then allowed to stand for 12 hours for degassing to obtain a casting solution;

[0065] (3) Preparation of basement membrane

[0066] The film scraping gap of the flat film scraper is fixed to 500 μm, 40 mL of casting liquid is poured into one end of the glass plate of the film scraper, and the casting liquid is evenly scraped on the glass plate with the film scraper at a constant speed of 6 cm / s, and the glass film coated with the casting liquid is immersed in a coagulation bath of a mass fraction of N,N-dimethylacetamide aqueous solution for 60 minutes to complete the curing of the base film;

[0067] (4) In situ cross-linking of basement membrane

[0068] The cured base membrane was transferred from the coagulation bath to deionized water, and soaked at a constant temperature of 60°C for 1 hour, during which the water was changed 5 times to remove the residual solvent and pore-forming agent polyethylene glycol; the base membrane was placed in a mixed solution of aniline and sodium polystyrene sulfonate (PSS) (the mass ratio of aniline to PSS was 1:1, and the aniline concentration was 1.0wt%), and soaked at 4°C for 30 minutes. Then, it was taken out and immersed in 0.16mol / L ammonium persulfate solution again, reacted for 10 minutes, and then placed at 4°C for reaction for 6 hours. Subsequently, it was taken out and entered into an acidic solution of glutaraldehyde (the solvent was hydrochloric acid, and the concentration of glutaraldehyde was 2wt%) for cross-linking for 45 minutes, and then washed with pure water and soaked in pure water.

[0069] The molecular weight cutoff of the conductive membrane prepared in Example 2 is 100 kDa, and the conductivity is 22 S / m.

[0070] Example 3

[0071] The preparation method of the carbon nanotube blended conductive film specifically comprises the following steps:

[0072] (1) Oxygen functional group modification of carbon nanotubes

[0073] The carbon nanotubes were evenly distributed in a crystallization dish, and placed in an oxygen plasma generator, with a plasma radio frequency power of 80 W, a radio frequency of 13.56 MHz, a chamber pressure of 60 Pa, and a modification time of 15 s. The process was repeated 3 times to obtain oxygen functional group-modified carbon nanotubes, wherein the oxygen content was 0.2 wt%;

[0074] (2) Preparation of casting solution

[0075] According to the mass ratio of carbon nanotubes modified with oxygen functional groups, polyethersulfone, polyvinyl pyrrolidone and polyethylene glycol being 2:3:1:1, carbon nanotubes modified with oxygen functional groups, polyethersulfone and polyvinyl pyrrolidone are added to N,N-dimethylacetamide, and stirred evenly at room temperature for 36 hours to obtain a dispersion liquid, and then polyethylene glycol is added at a constant temperature of 60°C, stirred until completely dissolved, and then allowed to stand for 24 hours for degassing to obtain a casting solution;

[0076] (3) Preparation of basement membrane

[0077] The film scraping gap of the flat film scraper is fixed to 450 μm, 30 mL of casting liquid is poured into one end of the glass plate of the film scraper, and the casting liquid is evenly scraped on the glass plate with the film scraper at a constant speed of 7 cm / s, and the glass film coated with the casting liquid is immersed in a coagulation bath of a mass fraction of N,N-dimethylacetamide aqueous solution for 30 minutes to complete the curing of the base film;

[0078] (4) In situ cross-linking of basement membrane

[0079] The cured base membrane was transferred from the coagulation bath to deionized water, and soaked at a constant temperature of 45°C for 1 hour, during which the water was changed 5 times to remove residual solvent and pore-forming agent polyethylene glycol; the base membrane was placed in a mixed solution of aniline and sodium polystyrene sulfonate (PSS) (the mass ratio of aniline to PSS was 1:1, and the aniline concentration was 1.0wt%), and soaked at 4°C for 45 minutes. Then, it was taken out and immersed in an ammonium persulfate solution again, reacted for 5 minutes, and then placed at 4°C for 4 hours. Subsequently, it was taken out and placed in an acidic solution of glutaraldehyde (the solvent was hydrochloric acid, and the concentration of glutaraldehyde was 2wt%) for cross-linking for 30 minutes, and then washed with pure water and soaked in pure water.

[0080] The molecular weight cutoff of the conductive membrane prepared in Example 3 is 200 kDa, and the conductivity is 10.4 S / m.

[0081] Application Example 1

[0082] The conductive membrane prepared in Example 1 was used as a membrane electrode and coupled with electro-activated peracetic acid to treat water. The total organic carbon concentration was 10 mg L -1 The algae extracellular polymer solution is used as the raw solution to be treated, which specifically includes the following steps:

[0083] (1) Encapsulating a conductive film in a flat membrane assembly, with the membrane serving as a working electrode, and arranging a counter electrode metal mesh of the same area opposite the membrane inside the assembly, with the distance between the metal mesh and the flat membrane being 8 mm. Leading wires from the metal mesh, connecting the metal electrode clip and the wires to the conductive film, and connecting the two-stage wires to an external DC regulated power supply;

[0084] (2) adding 2 mg / L of peracetic acid to the raw liquid to be treated, and applying voltage to the conductive membrane through a DC voltage-stabilized power supply to filter the liquid. The filtering method is cross-flow filtration, and the filtering pressure of the membrane assembly is adjusted to be constant at 1.0 bar.

[0085] (3) Under the condition of a cross-flow velocity of 0.05 m / s, the conductive membrane has good anti-pollution performance. A voltage of 2.0 V is applied to the conductive membrane and filtered for 2 h. Figure 4 The flux decrease curve of the algal extracellular polymer solution during filtration. The flux only dropped from 100 L m to 100 L m within 2 h. -2 h -1 bar -1 Down to 90.4L m -2 h -1 bar -1 , the flux decrease rate was less than 10%, showing good anti-pollution performance. Figure 5 The removal effect of microcystin by conductive membrane filtration process. The concentration of microcystin in the raw water is 2.7 μg L -1 When no voltage was applied to the conductive membrane, the concentration of microcystin in the effluent was 1.6 μg L -1 When a voltage of 2.0 V was applied to the conductive membrane, the concentration of microcystin in the effluent was below the detection limit (0.01 μg L -1 ), the removal rate is about 100%.

[0086] Application Example 2

[0087] The conductive membrane prepared in Example 2 was used as a membrane electrode and coupled with electro-activated peracetic acid to treat water. -1 The humic acid solution with a total organic carbon concentration of 5 mg L -1 The mixed solution of the algae extracellular polymer solution is used as the simulated algae-source contaminated water to be treated, which specifically includes the following steps:

[0088] (1) Encapsulating a conductive film in a flat membrane assembly, with the membrane serving as a working electrode, and arranging a counter electrode metal mesh of the same area opposite the membrane inside the assembly, with the distance between the metal mesh and the flat membrane being 8 mm. Leading wires from the metal mesh, connecting the metal electrode clip and the wires to the conductive film, and connecting the two-stage wires to an external DC regulated power supply;

[0089] (2) adding 5 mg / L of peracetic acid to the raw liquid to be treated, and applying voltage to the conductive membrane through a DC stabilized power supply to filter the liquid. The filtering method is cross-flow filtration, and the filtering pressure of the membrane assembly is adjusted to be constant at 1.0 bar.

[0090] (3) Under the condition of a cross-flow velocity of 0.08 m / s, the conductive membrane has good anti-pollution performance. When a voltage of 2.5 V is applied to the conductive membrane, the flux decreases by only 14% after 2 h of filtration, and the removal rate of pollutants in simulated algae-contaminated water is 94.2%.

[0091] Application Example 3

[0092] The conductive membrane prepared in Example 3 was used as a membrane electrode and coupled with electro-activated peracetic acid to treat water. Surface water contaminated by algae was used as the treated stock solution, and its permanganate index was 4.2 mg L -1 The concentration of microcystin was 1.4 μg L -1 , the turbidity is 2.3NTU, specifically including the following steps:

[0093] (1) Encapsulating a conductive film in a flat membrane assembly, with the membrane serving as a working electrode, and arranging a counter electrode metal mesh of the same area opposite the membrane inside the assembly, with the distance between the metal mesh and the flat membrane being 10 mm. Leading wires from the metal mesh, connecting the metal electrode clip and the wires to the conductive film, and connecting the two-stage wires to an external DC regulated power supply;

[0094] (2) adding 1.5 mg / L peracetic acid to the raw liquid to be treated, and applying voltage to the conductive membrane through a DC voltage-stabilized power supply to filter the liquid. The filtering method is cross-flow filtration, and the filtering pressure of the membrane assembly is adjusted to be constant at 0.5 bar.

[0095] (3) Under the condition of a cross-flow velocity of 0.02 m / s, the conductive membrane has good anti-pollution performance. When a voltage of 2.5 V is applied to the conductive membrane, the flux decreases by only 12% after 2 h of filtration. The removal rate of permanganate is 81.1%, and the removal rate of microcystin detected in algae-contaminated surface water is 100%.

[0096] The embodiments described above are only typical embodiments of the present invention and do not constitute improper limitations on the present invention. Therefore, all obvious modifications described in the scope of the patent application of the present invention and other modifications that do not deviate from the essence of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a carbon nanotube blended conductive film, characterized in that: The steps include: (1) Oxygen functional group modification of carbon nanotubes The carbon nanotubes are evenly distributed in a crystallization dish and placed in an oxygen plasma generator for treatment to obtain carbon nanotubes modified with oxygen functional groups; (2) Preparation of casting solution Adding oxygen functional group-modified carbon nanotubes, polyethersulfone and polyvinyl pyrrolidone to a solvent, stirring evenly at room temperature for 18 to 36 hours to obtain a dispersion, then adding polyethylene glycol at a constant temperature of 50 to 80° C., stirring until completely dissolved, and then standing to degas, to obtain a casting solution; (3) Preparation of basement membrane The casting liquid is scraped onto a glass plate, and the glass plate coated with the casting liquid is immersed in a coagulation bath for 30 minutes to complete the curing of the base film; (4) In situ cross-linking of basement membrane The cured base film is transferred from the coagulation bath to deionized water for washing, and the base film is placed in a mixture of aniline and sodium poly(p-styrene sulfonate) and soaked at 4°C for 20 to 30 minutes. The base film is then taken out and immersed in an ammonium persulfate solution to react for 5 to 10 minutes. The base film is then placed at 4°C to react for 3 to 6 hours. The base film is then taken out and placed in an acidic solution of glutaraldehyde for cross-linking, and then washed with pure water and immersed in pure water to obtain a carbon nanotube blended conductive film.

2. The preparation method according to claim 1, characterized in that: In step (1), the oxygen content of the carbon nanotubes modified with oxygen functional groups is 0.1 to 0.5 wt %; The plasma radio frequency power is 50-100 W, the radio frequency frequency is 13.56 MHz, the gas pressure in the chamber is 50-100 Pa, and the processing time is 10-60 s.

3. The preparation method according to claim 1, characterized in that: In step (2), the solvent is one or a mixture of two of N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide; The molecular weight of the polyethylene glycol is 50,000 to 300,000.

4. The preparation method according to claim 1, characterized in that: In step (2), the mass fraction of the solute in the casting solution is 30-60%.

5. The preparation method according to claim 1, characterized in that: In step (2), in the casting solution, the mass ratio of oxygen functional group-modified carbon nanotubes, polyethersulfone, polyvinyl pyrrolidone, and polyethylene glycol is (2-3):3:1:

1.

6. The preparation method according to claim 1, characterized in that: In step (3), the film scraping gap of the flat film scraper is 300 to 500 μm, and the film is scraped at a constant speed of 5 to 10 cm / s; The coagulation bath is a 10-20 wt % N,N-dimethylacetamide aqueous solution, and the temperature of the coagulation bath is 20-25° C.

7. The preparation method according to claim 1, characterized in that: In step (4), the basement membrane is soaked and washed at a constant temperature of 40 to 60° C. for 0.5 to 1 h; The cross-linking time of the glutaraldehyde is 30 to 60 minutes.

8. The preparation method according to claim 1, characterized in that: In step (4), in the mixed solution of aniline and sodium poly(p-styrene sulfonate), the mass ratio of aniline to sodium poly(p-styrene sulfonate) is 1:1, and the concentration of aniline is 0.5-2.0 wt%.

9. A carbon nanotube blended conductive film obtained by the preparation method according to any one of claims 1 to 8.

10. A method for controlling algae pollution by coupling carbon nanotube blended conductive membrane with electro-activated peracetic acid, characterized in that: Using the carbon nanotube blended conductive membrane described in claim 9 as a membrane electrode, during the treatment of algae-contaminated water, peracetic acid is added to the influent at a concentration of 0.5 to 5 mg / L, a voltage of 0.5 to 3 V is applied to the membrane, the filtration form is constant pressure cross-flow filtration, the filtration pressure is 0.5 to 2.0 bar, and the cross-flow velocity is 0.05 to 0.1 m / s.

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