Anti-fouling oil-water separation membrane based on joule heating effect and preparation method thereof

Abstract

The application discloses an anti-pollution oil-water separation membrane based on Joule heat effect and a preparation method thereof, and belongs to the technical field of functional materials. The preparation method comprises the following steps: sequentially placing a base film in anhydrous ethanol and deionized water for ultrasonic cleaning for 5-15 min to obtain a pretreated base film; adding carbon nanotubes into anhydrous ethanol and ultrasonically dispersing for 20-40 min to obtain a carbon nanotube dispersion liquid; injecting the carbon nanotube dispersion liquid into a vacuum filtration device to uniformly deposit the carbon nanotubes on the surface of the pretreated base film, and drying to obtain a pretreated film with the carbon nanotubes loaded on the surface; placing the pretreated film in a dopamine aqueous solution, adjusting the pH of the system to 8-9, stirring and reacting for 10-12 h, washing with deionized water after the reaction, and drying to obtain an anti-pollution oil-water separation membrane. The two ends of the membrane are connected with positive and negative electrodes respectively, the oil-water emulsion separation performance of the membrane is strengthened by utilizing Joule heat, and the continuous separation capacity of the strengthened membrane is improved in the process of water permeation and oil blocking.

Description

Technical Field

[0001] This application relates to an anti-fouling oil-water separation membrane based on the Joule heating effect and its preparation method, belonging to the field of functional materials technology. Background Technology

[0002] Membrane separation technology boasts advantages such as high separation efficiency, simple operation, small equipment footprint, and no need for chemical reagents during the treatment process, making it widely used in the treatment of oily wastewater. However, during the separation process, oil droplets easily adsorb, aggregate, or clog the membrane pores on the membrane surface, causing a sharp reduction in flux and deterioration in separation performance. Membrane fouling has become a core bottleneck restricting the long-term stable operation and large-scale application of this technology.

[0003] In oil extraction and gathering processes, thermal regulation has been widely used to improve the rheological properties of crude oil, significantly reducing the viscous resistance of high-viscosity oil phases and regulating interfacial physicochemical properties. Given the crucial role of thermal effects on oil phase properties and interfacial behavior, introducing it into membrane separation processes is expected to fundamentally intervene in the migration and retention behavior of oil droplets at the membrane interface, providing a new approach to solving membrane fouling. However, traditional bulk heating methods suffer from drawbacks such as high energy consumption, low thermal efficiency, and high operating costs. Furthermore, fouling primarily occurs in the membrane interface region, making precise control of macroscopic bulk heating difficult, leading to ineffective energy loss.

[0004] Chinese invention patent application CN121606927A discloses a method for preparing a Joule-heat-assisted superwetting metal mesh, a metal mesh with superhydrophilic properties, and a metal mesh with superhydrophobic properties. Joule heating-assisted preparation achieves in-situ viscosity reduction of crude oil on the superhydrophobic side, thereby increasing crude oil throughput and avoiding pore blockage. However, the pore size of this metal mesh is in the micrometer or even hundreds of micrometer range. When faced with highly stable nanoscale water-in-oil or oil-in-water emulsions, it is prone to penetration, resulting in poor separation accuracy. Furthermore, during long-term treatment of complex oily wastewater and repeated electrothermal heating, the metal mesh faces the risk of rust and corrosion, resulting in insufficient continuous separation capacity. In addition, the above preparation method first mixes dopamine and carbon nanotubes before modifying the metal mesh. When dopamine self-polymerizes in solution, it pre-encapsulates the surface of free carbon nanotubes. When these nanotubes are deposited on the mesh, the insulating polydopamine layer blocks the junctions between the carbon nanotubes, significantly increasing contact resistance and weakening the Joule heating effect. Summary of the Invention

[0005] To address the aforementioned issues, an antifouling oil-water separation membrane based on the Joule heating effect and its preparation method are provided. The membrane is connected to positive and negative electrodes at both ends, and the oil-water emulsion separation performance of the membrane is enhanced by utilizing Joule heating. During the water permeation and oil separation process, the membrane's continuous separation capability is strengthened.

[0006] According to one aspect of this application, a method for preparing an antifouling oil-water separation membrane based on the Joule heating effect is provided, comprising the following steps: (1) The basement membrane was placed in anhydrous ethanol and deionized water for ultrasonic cleaning for 5-15 min each to obtain a pretreated basement membrane; (2) Add carbon nanotubes to anhydrous ethanol and ultrasonically disperse for 20-40 min to obtain a carbon nanotube dispersion; (3) Inject the carbon nanotube dispersion into a vacuum filtration device to uniformly deposit the carbon nanotubes onto the surface of the pretreated substrate membrane, and dry it to obtain a pretreated membrane with surface-loaded carbon nanotubes. (4) The pretreated membrane with surface-loaded carbon nanotubes was placed in a dopamine aqueous solution, the pH of the system was adjusted to 8-9, and the reaction was stirred for 10-12 hours. After the reaction was completed, the membrane was washed with deionized water and dried to obtain an anti-fouling oil-water separation membrane.

[0007] Optionally, the base membrane is a polytetrafluoroethylene membrane, a polyvinylidene fluoride membrane, or a nylon membrane.

[0008] Optionally, the thickness of the base film is 108–112 μm.

[0009] Optionally, the concentration of the carbon nanotube dispersion is 40–60 mg / L.

[0010] Optionally, the ultrasonic power is 1000-1500W.

[0011] Optionally, the filtration pressure is 0.05 to 0.15 bar.

[0012] Optionally, the concentration of the dopamine aqueous solution is 1 to 3 g / L.

[0013] Optionally, the drying temperature is 50–70°C.

[0014] Optionally, the anti-fouling oil-water separation membrane has a pore size of 500–700 nm and a thickness of 118–122 μm.

[0015] According to another aspect of this application, an antifouling oil-water separation membrane based on the Joule heating effect is provided, said antifouling oil-water separation membrane based on the Joule heating effect is prepared by any of the methods described above.

[0016] The beneficial effects of this application include, but are not limited to: 1. This application discloses an antifouling oil-water separation membrane based on the Joule heating effect and its preparation method. First, a porous membrane substrate is pre-cleaned. Then, a carbon nanotube dispersion is deposited onto the membrane surface via vacuum filtration to construct a continuous conductive network layer. Next, the resulting composite membrane is immersed in a dopamine aqueous solution, and a polydopamine functional coating is grown in situ on its surface through a self-polymerization reaction, ultimately obtaining the target oil-water separation membrane. This separation membrane, acting as a resistive layer in the Joule heating system, can achieve rapid in-situ heating when a voltage is applied across its ends, thereby precisely controlling the membrane interface temperature. The increased interface temperature promotes the demulsification of emulsified oil droplets and enhances the desorption and removal of contaminated oil, thus achieving stable and efficient oil-water separation performance. Simultaneously, during the Joule heating-assisted cleaning process, localized high temperatures significantly reduce oil phase adhesion and weaken its interfacial adhesion force. Furthermore, the microbubbles generated by thermal induction can drive the deformation of attached oil droplets and cause the three-phase contact line to contract during their generation and evolution, thereby enhancing the oil droplet peeling behavior. This separation membrane exhibits excellent antifouling performance and stable flux recovery capability in complex oil-containing systems, and has broad application prospects in the field of oily wastewater treatment.

[0017] 2. The antifouling oil-water separation membrane based on the Joule heating effect and its preparation method described in this application utilize a substrate membrane with excellent acid and alkali resistance, corrosion resistance, and thermal stability, enabling it to withstand the extremely complex chemical environment of oily wastewater for extended periods. Pure carbon nanotubes are deposited onto the substrate membrane via vacuum filtration, allowing direct physical contact between the carbon nanotubes to form a continuous, dense three-dimensional conductive network. This framework-building strategy ensures unobstructed electron transport pathways. After physical filtration deposition onto the membrane surface, the carbon nanotubes themselves have relatively weak binding forces; subsequently introduced dopamine not only grows in situ on the carbon nanotube surface but also penetrates into the gaps in the carbon nanotube network and the pores of the substrate membrane, where it polymerizes. This polydopamine coating acts like super glue and armor, firmly locking and encapsulating the entire carbon nanotube network onto the base membrane, forming the outermost interface of the membrane. This greatly enhances the mechanical stability of the electrothermal layer, preventing carbon nanotubes from detaching during long-term, high-flux water scouring and high-temperature bubble stripping, while successfully achieving the transformation from superhydrophilic to underwater superoleophobic.

[0018] 3. The antifouling oil-water separation membrane based on the Joule heating effect and its preparation method of this application employ a relatively low concentration of carbon nanotube suspension, which can reduce the probability of collision and entanglement of carbon nanotubes per unit volume from the source. Simultaneously, it abandons the pure water system and deliberately selects anhydrous ethanol as the dispersion medium, which has lower surface tension and can better wet the originally hydrophobic carbon nanotube surface, thus weakening their aggregation tendency from a chemical environment perspective. Furthermore, the carbon nanotubes undergo prolonged ultrasonic dispersion treatment; this allows the highly dispersed carbon nanotube suspension to rapidly pass vertically downwards through the micropores of the substrate membrane during subsequent negative pressure filtration. Under this directional and uniform fluid drag force, the carbon nanotubes originally suspended in the liquid are instantly pulled and uniformly and evenly deposited on the substrate membrane surface. Because the deposition process is extremely fast and subjected to vertical downward pressure, the carbon nanotubes do not have time to become free or secondary aggregate on the membrane surface, ultimately resulting in forced solidification to form a continuous and dense three-dimensional porous carbon nanotube network. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a photograph of the separation membrane provided in Embodiment 1 of this application.

[0020] Figure 2 This is an electron microscope image of the separation membrane provided in Example 1 of this application.

[0021] Figure 3 The image shows the wettability test results of the separation membrane provided in Example 1 of this application.

[0022] Figure 4 This is a diagram showing the interface temperature control performance of the separation membrane after wetting provided in Example 1 of this application.

[0023] Figure 5 This is a diagram showing the electrothermal-induced demulsification behavior of the separation membrane provided in Embodiment 1 of this application after wetting.

[0024] Figure 6 This is a test diagram of the high-temperature bubble-assisted oil removal performance of the separation membrane provided in Example 1 of this application after wetting.

[0025] Figure 7 This is a comparison chart showing the improvement in antifouling performance of the separation membrane in Example 1 of this application under energized conditions.

[0026] Figure 8 This is a graph showing the water flux recovery rate after the separation membrane of Example 1 of this application is circulated and separated under energized conditions. Detailed Implementation

[0027] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0028] Unless otherwise specified in the examples, the procedures shall be performed under standard conditions or conditions recommended by the manufacturer. Raw materials or instruments whose manufacturers are not specified are all commercially available products.

[0029] The thickness of the base membrane involved in the following examples and comparative examples is 110 μm, and the thickness of the oil-water separation membrane is 120 μm.

[0030] Example 1 A method for preparing an antifouling oil-water separation membrane based on the Joule heating effect includes the following steps: (1) The polytetrafluoroethylene (PTFE) membrane was placed in anhydrous ethanol and deionized water for 10 min each, and the ultrasonic power was 1300W to remove the residual lipids and processing impurities on its surface and obtain the pretreated base membrane. (2) Weigh 0.0025g of multi-walled carbon nanotubes, add them to 50mL of anhydrous ethanol, and ultrasonically disperse them at 1300W for 30min to obtain a carbon nanotube suspension with a concentration of 50mg / L. (3) Vacuum filtration was performed under a negative pressure of 0.1 bar to allow the carbon nanotube suspension to pass continuously through the polytetrafluoroethylene membrane. The carbon nanotubes were intercepted and uniformly deposited on the membrane surface. After deposition, the membrane was dried at 60°C to obtain a pretreated membrane with carbon nanotubes loaded on the surface. (4) The pretreated membrane with carbon nanotubes loaded on the surface was immersed in a dopamine aqueous solution with a concentration of 2 g / L, the pH of the system was adjusted to 8.5, and the reaction was carried out for 11 h under slow stirring to deposit and grow a polydopamine coating on the surface. After the reaction was completed, it was repeatedly washed with deionized water and dried at 60°C to obtain an anti-fouling oil-water separation membrane with a pore size of 600 nm.

[0031] Test results: Figure 1 , Figure 2 and Figure 3 The images shown are photographs, electron microscope images, and wettability test results of the separation membrane from Example 1. Figure 1 and Figure 2 As shown, the modified membrane has a dark black appearance, and its surface is composed of a three-dimensional porous network structure made up of densely interwoven carbon nanotubes. Figure 3The evolution of the wettability of the membrane at different modification stages was demonstrated: after carbon nanotube (CNT) filtration, the water contact angle of the membrane was 127° and the underwater oil contact angle was 95°, showing certain hydrophobic properties; after further modification with polydopamine (PDA), the water contact angle of the membrane decreased to 0° and the underwater oil contact angle increased to 166°, indicating that it was successfully transformed into a superwetting surface with superhydrophilic underwater superoleophobic properties.

[0032] Figure 4 , Figure 5 and Figure 6 The figures show the interface temperature control performance of the separation membrane after wetting in Example 1, the electrothermal induced demulsification behavior, and the high-temperature bubble-assisted oil removal performance test results. Figure 4 It can be seen that the highest interface temperature of the separation membrane after wetting increases significantly with the increase of the applied voltage, reaching 102 °C under 40 V conditions, indicating that the membrane has good electro-response temperature control capability. Figure 5 This indicates that in a surfactant-stabilized oil-water system, oil droplets undergo significant coalescence within 35 seconds after being energized and affected by temperature, demonstrating that the film possesses excellent demulsification capabilities. Figure 6 The results show that under the influence of high temperature and thermally induced bubbles, the paste-like crude oil on the membrane first softens due to the decrease in viscosity, thereby reducing the adhesion. Subsequently, it is peeled off from the surface by the bubbles, demonstrating the membrane's efficient decontamination capability.

[0033] Figure 7 and Figure 8 This section presents a comparison chart of the antifouling performance improvement of the separation membrane in Example 1 under energized conditions, and a curve showing the water flux recovery rate after circulating separation. From... Figure 7 It can be seen that under continuous energizing conditions, the flux decay rate of the separation membrane is significantly reduced, indicating that its antifouling performance is effectively improved. Figure 8 The results show that after multiple cycles of separation, the membrane's water flux recovery rate can still be maintained at 94.82%, demonstrating its excellent recoverability and stable antifouling performance.

[0034] Example 2 A method for preparing an antifouling oil-water separation membrane based on the Joule heating effect includes the following steps: (1) The polyvinylidene fluoride membrane was placed in anhydrous ethanol and deionized water for 5 min each, and the ultrasonic power was 1000W to remove the residual lipids and processing impurities on its surface and obtain the pretreated base membrane. (2) Weigh 0.002 g of multi-walled carbon nanotubes, add them to 50 mL of anhydrous ethanol, and ultrasonically disperse them at 1000 W for 20 min to obtain a carbon nanotube suspension with a concentration of 40 mg / L. (3) Vacuum filtration was performed under a negative pressure of 0.05 bar to allow the carbon nanotube suspension to pass continuously through the polyvinylidene fluoride membrane. The carbon nanotubes were intercepted and uniformly deposited on the membrane surface. After deposition, the membrane was dried at 50°C to obtain a pretreated membrane with carbon nanotubes loaded on the surface. (4) The pretreated membrane with carbon nanotubes loaded on the surface was immersed in a dopamine aqueous solution with a concentration of 1 g / L, the pH of the system was adjusted to 8, and the reaction was carried out for 10 h under slow stirring to deposit and grow a polydopamine coating on the surface. After the reaction was completed, it was repeatedly washed with deionized water and dried at 50 °C to obtain an anti-fouling oil-water separation membrane with a pore size of 700 nm.

[0035] Test results: The membrane separation flux was 6550 liters / square meter / hour / kPa and 96°C at 40V. The electrical response temperature control capability was not as good as that of Example 1.

[0036] Example 3 A method for preparing an antifouling oil-water separation membrane based on the Joule heating effect includes the following steps: (1) The nylon membrane was placed in anhydrous ethanol and deionized water for ultrasonic cleaning for 15 min each, with an ultrasonic power of 1500W, to remove residual lipids and processing impurities on its surface and obtain a pretreated basement membrane. (2) Weigh 0.003 g of multi-walled carbon nanotubes, add them to 50 mL of anhydrous ethanol, and ultrasonically disperse them at 1500 W for 40 min to obtain a carbon nanotube suspension with a concentration of 60 mg / L. (3) Vacuum filtration was performed under a negative pressure of 0.15 bar to allow the carbon nanotube suspension to pass through the nylon membrane continuously. The carbon nanotubes were intercepted and uniformly deposited on the membrane surface. After deposition, the membrane was dried at 70°C to obtain a pretreated membrane with carbon nanotubes loaded on the surface. (4) The pretreated membrane with surface-loaded carbon nanotubes was immersed in a dopamine aqueous solution with a concentration of 3 g / L, the pH of the system was adjusted to 9, and the reaction was carried out for 12 h under slow stirring to deposit and grow a polydopamine coating on its surface. After the reaction was completed, it was repeatedly washed with deionized water and dried at 70 °C to obtain an anti-fouling oil-water separation membrane with a pore size of 500 nm.

[0037] Test results: The membrane separation flux was 5300 liters / square meter / hour / kPa and 108°C at 40V. The electro-response temperature control capability was higher than that of Example 1.

[0038] Comparative Example 1 The difference from Example 1 is that the polytetrafluoroethylene membrane is replaced with a 2500-mesh (5μm pore size) metal mesh.

[0039] Test results: As the membrane pore size increases, the throttling rate of the oil-water emulsion decreases, and the separation performance deteriorates.

[0040] In Comparative Example 1, the pore size of the metal mesh is at the micrometer level. When faced with highly stable nanoscale water-in-oil or oil-in-water emulsions, it is prone to penetration, resulting in poor separation accuracy. The polytetrafluoroethylene membrane selected in Example 1 of this application has extremely excellent acid and alkali resistance, corrosion resistance, and thermal stability in materials science. When treating complex oily wastewater for a long time and repeatedly heating it with electricity, it will not face the risk of rusting and corrosion like the metal mesh.

[0041] Comparative Example 2 The difference from Example 1 is that step (2) is: Weigh 0.005 g of multi-walled carbon nanotubes and add them to 50 mL of anhydrous ethanol. Disperse the mixture by sonication for 30 min to obtain a carbon nanotube suspension with a concentration of 100 mg / L.

[0042] Test results: The membrane separation flux was 3000 liters / square meter / hour / kPa, which was significantly lower than that of Example 1.

[0043] Compared with Comparative Example 2, Example 1 uses a relatively low concentration of carbon nanotube suspension, which can reduce the probability of collision and entanglement of carbon nanotubes per unit volume from the source and avoid aggregation.

[0044] Comparative Example 3 A method for preparing an oil-water separation membrane includes the following steps: (1) The polytetrafluoroethylene membrane was placed in anhydrous ethanol and deionized water for ultrasonic cleaning for 10 min each to remove residual lipids and processing impurities on its surface and obtain a pretreated base membrane. (2) Weigh 0.0025g of multi-walled carbon nanotubes, add them to a dopamine aqueous solution, and ultrasonically disperse for 30min to obtain a polydopamine-modified carbon nanotube dispersion; (3) The pretreated base membrane was immersed in a polydopamine-modified carbon nanotube dispersion with a concentration of 2 g / L. The pH of the system was adjusted to 8.5 and the reaction was carried out for 11 h under slow stirring to deposit and grow a polydopamine-modified carbon nanotube coating on its surface. After the reaction was completed, it was repeatedly washed with deionized water and dried at 60 °C to obtain an oil-water separation membrane.

[0045] Test results: The Joule thermal properties of the membrane decreased significantly, reaching 82℃ at 40V.

[0046] Compared to Example 1, Comparative Example 3 first mixed dopamine and carbon nanotubes before modifying the base film. When dopamine self-polymerizes in solution, it pre-encapsulates the surface of free carbon nanotubes. When they are deposited on the film, the insulating polydopamine layer blocks the junctions between carbon nanotubes, significantly increasing the contact resistance and weakening the Joule heating effect.

[0047] Comparative Example 4 A method for preparing an oil-water separation membrane includes the following steps: (1) The polytetrafluoroethylene membrane was placed in anhydrous ethanol and deionized water for ultrasonic cleaning for 10 min each to remove residual lipids and processing impurities on its surface and obtain a pretreated base membrane. (2) Weigh 0.0025g of multi-walled carbon nanotubes, add them to 50mL of anhydrous ethanol, and sonicate for 30min to obtain a carbon nanotube suspension with a concentration of 50mg / L. (3) Immerse the pretreated base membrane in a 2 g / L dopamine aqueous solution, adjust the pH of the system to 8.5, and react for 11 h under slow stirring to deposit and grow a polydopamine coating on its surface. After the reaction is complete, wash repeatedly with deionized water and dry at 60 °C to obtain a pretreated membrane with polydopamine loaded on its surface. (4) Vacuum filtration is performed under a negative pressure of 0.1 bar, so that the carbon nanotube suspension passes continuously through the pretreated membrane loaded with polydopamine. The carbon nanotubes are intercepted and uniformly deposited on the membrane surface. After deposition, the membrane is dried at 60°C to obtain an oil-water separation membrane.

[0048] Test results: Comparative Example 4 constructed a superhydrophobic underwater superoleophilic surface, while Example 1 constructed a superhydrophilic underwater superoleophobic surface. That is, Comparative Example 4 is oil-permeable and water-separated (upper layer is water, lower layer is oil), while Example 1 is water-permeable and oil-separated. Furthermore, polydopamine in Comparative Example 4 acts as an intermediate layer, connecting other hydrophobic materials, while in Example 1, polydopamine is used to hydrophilically modify the membrane surface after filtration. In Example 1, Joule heating is used to enhance the oil-water emulsion separation performance of the membrane, strengthening the membrane's continuous separation capability during the water-permeable and oil-separated process.

[0049] Comparative Example 5 The difference from Example 1 is that step (3) is: The pretreated substrate membrane was immersed in a carbon nanotube suspension and stirred thoroughly to allow the carbon nanotubes to be uniformly deposited on the surface of the pretreated substrate membrane. After deposition, it was dried at 60°C to obtain a pretreated membrane with carbon nanotubes loaded on its surface.

[0050] Test results: The membrane surface has few and uneven carbon nanotubes, which leads to a decrease in the membrane's Joule heating properties and oil-water separation performance.

[0051] Compared with Comparative Example 5, Example 1 deposits carbon nanotubes through negative pressure filtration, allowing the liquid to pass vertically downwards rapidly through the micropores of the substrate membrane. Under this directional and uniform fluid drag force, the carbon nanotubes, which were originally suspended in the liquid, are instantly pulled and uniformly and flatly deposited on the surface of the substrate membrane. Because the deposition process is extremely fast and is compressed by the vertical downward force, the carbon nanotubes do not have time to become free and aggregated again on the membrane surface, and are ultimately forced to solidify to form a continuous and dense "three-dimensional porous carbon nanotube network".

[0052] Comparative Example 6 The difference from Example 1 is that step (2) is: Weigh 0.0025 g of multi-walled carbon nanotubes, add them to 50 mL of deionized water, and sonicate for 30 min to obtain a carbon nanotube suspension with a concentration of 50 mg / L.

[0053] Test results: The carbon nanotubes on the membrane surface were unevenly deposited, resulting in decreased Joule heating performance and reduced oil-water separation performance.

[0054] Compared with Comparative Example 6, Example 1 abandoned the pure water system and deliberately selected anhydrous ethanol as the dispersion medium. The surface tension is lower, which can better wet the carbon nanotube surface that originally has a certain degree of hydrophobicity, thereby reducing their tendency to aggregate from a chemical environment perspective.

[0055] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing an antifouling oil-water separation membrane based on the Joule heating effect, characterized in that, Includes the following steps: (1) The basement membrane was placed in anhydrous ethanol and deionized water for ultrasonic cleaning for 5-15 min each to obtain a pretreated basement membrane; (2) Add carbon nanotubes to anhydrous ethanol and ultrasonically disperse for 20-40 min to obtain a carbon nanotube dispersion; (3) Inject the carbon nanotube dispersion into a vacuum filtration device to uniformly deposit the carbon nanotubes onto the surface of the pretreated substrate membrane, and dry it to obtain a pretreated membrane with surface-loaded carbon nanotubes. (4) The pretreated membrane with surface-loaded carbon nanotubes was placed in a dopamine aqueous solution, the pH of the system was adjusted to 8-9, and the reaction was stirred for 10-12 hours. After the reaction was completed, it was washed with deionized water and dried to obtain an anti-fouling oil-water separation membrane. The base membrane is a polytetrafluoroethylene membrane, a polyvinylidene fluoride membrane, or a nylon membrane; The concentration of the carbon nanotube dispersion is 40–60 mg / L; The filtration pressure is 0.05–0.15 bar; The concentration of the dopamine aqueous solution is 1–3 g / L.

2. The preparation method according to claim 1, characterized in that, The thickness of the basement membrane is 108–112 μm.

3. The preparation method according to claim 1, characterized in that, The ultrasonic power is 1000-1500W.

4. The preparation method according to claim 1, characterized in that, The drying temperature is 50–70°C.

5. The preparation method according to claim 1, characterized in that, The anti-fouling oil-water separation membrane has a pore size of 500–700 nm and a thickness of 118–122 μm.

6. A fouling-resistant oil-water separation membrane based on the Joule heating effect, characterized in that, The antifouling oil-water separation membrane based on the Joule heating effect is prepared by the method described in any one of claims 1 to 5.

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