A wettability-controllable conductive composite film, a preparation method and a film processing device

Abstract

The application discloses a preparation method of a wettability-regulating conductive composite film and belongs to the technical field of water treatment equipment. The method comprises the following steps: preparing an oxidant solution; adding a nitrogen-containing heterocyclic compound into the oxidant solution under ice bath conditions to obtain a conductive solution; immersing a substrate support layer into the conductive solution to obtain a conductive polymer layer; mixing dopamine hydrochloride and sodium alginate to prepare a hydrophilic modification liquid; and immersing the conductive polymer layer into the hydrophilic modification liquid to form a conductive composite film after static immersion under room temperature conditions. The conductive composite film has strong decontamination capacity, can effectively inhibit membrane pollution, including composite pollution of complex pollutants, has slow flux attenuation, has simple and effective cleaning mode, and has high membrane flux recovery rate.

Description

Technical Field

[0001] This invention relates to a wettability-controlled conductive composite membrane, its preparation method, and a membrane treatment device, belonging to the technical field of water treatment equipment. Background Technology

[0002] Membrane filtration technology utilizes semi-permeable membranes with selective separation capabilities to physically separate mixtures. However, during membrane filtration, contaminants (suspended particles, colloids, and organic matter) are easily adsorbed and deposited on the membrane surface, forming a fouling layer. This leads to a rapid decline in membrane flux, requiring frequent chemical cleaning (such as acid washing and alkaline washing). This not only shortens the membrane's lifespan but may also cause secondary pollution and increase operating costs. Therefore, antifouling membranes have become a key technology in the water treatment field.

[0003] Antifouling membranes are membranes whose surface properties are optimized to reduce the adsorption or deposition of pollutants, thereby extending membrane lifespan, improving separation efficiency, and reducing cleaning frequency. Current antifouling membrane technologies mainly include hydrophilic modification and conductive modification. Hydrophilic modification involves introducing hydrophilic groups (such as hydroxyl and carboxyl groups) onto the membrane surface using chemical or physical methods to enhance the membrane's affinity for water. Conductive modification involves introducing charged groups (such as sulfonic acid groups and quaternary ammonium salts) onto the membrane surface to enhance the membrane's affinity for water. Both hydrophilic and conductive modifications reduce the contact area between pollutants and the membrane surface, thus lowering the risk of fouling.

[0004] However, this hydrophilic or conductive modified antifouling membrane technology is not only difficult to deal with complex pollutants, but also requires multiple devices to work together, such as electric field combined with photocatalysis, or magnetic separation combined with filtration membrane. It has a complex structure, high energy consumption, and is not suitable for small and medium-sized water treatment scenarios. Summary of the Invention

[0005] This invention provides a method for preparing a wettability-controlled conductive composite film, comprising:

[0006] Preparation of oxidant solution;

[0007] Under ice bath conditions, a nitrogen-containing heterocyclic compound is added to the oxidant solution to obtain a conductive solution;

[0008] The substrate support layer is immersed in the conductive solution to obtain a conductive polymer layer;

[0009] A hydrophilic modified solution was prepared by mixing dopamine hydrochloride and sodium alginate.

[0010] The conductive polymer layer is immersed in the hydrophilic modified liquid and statically impregnated at room temperature to form a conductive composite film.

[0011] The nitrogen-containing heterocyclic compound is a pyrrole monomer. Adding the nitrogen-containing heterocyclic compound to the oxidant solution yields a conductive solution comprising:

[0012] Under ice bath conditions, pyrrole monomer purified by distillation was added dropwise and stirred until homogeneous to obtain a conductive solution.

[0013] The conductive polymer layer is obtained by immersing the substrate support layer in the conductive solution, comprising:

[0014] Under ice bath conditions, the substrate support layer is immersed in the conductive solution and allowed to stand for polymerization to obtain a polymer film;

[0015] The polymer film was rinsed with deionized water and then dried in a vacuum drying oven to obtain a conductive polymer layer.

[0016] Furthermore, the ice bath conditions are 0℃-5℃, the static polymerization time is 2h-4h, and the thickness of the polymer film is 5μm-10μm.

[0017] The preparation of a hydrophilic modified solution by mixing dopamine hydrochloride and sodium alginate includes:

[0018] Dopamine hydrochloride was dissolved in a buffer solution to obtain a dopamine solution;

[0019] Sodium alginate was added to the dopamine solution to obtain a hydrophilic modified solution.

[0020] Furthermore, sodium alginate is added to the dopamine solution to obtain a hydrophilic modified solution, specifically:

[0021] Sodium alginate powder was added to the dopamine solution and stirred continuously for 30-90 minutes, then allowed to stand to remove bubbles to obtain a hydrophilic modified solution; wherein the concentration of dopamine hydrochloride was controlled at 1 mg / mL-5 mg / mL, and the concentration of sodium alginate was 2 mg / mL-6 mg / mL.

[0022] The thickness of the conductive composite film is 3μm-5μm.

[0023] Furthermore, after forming the conductive composite film, it also includes:

[0024] After rinsing the conductive composite membrane with deionized water, it is immersed in calcium chloride solution and allowed to stand.

[0025] The conductive composite film, after being left to stand, is placed in a vacuum drying oven for drying.

[0026] This invention also provides a conductive composite film prepared according to the above method, comprising: a substrate support layer, a conductive polymer layer, and a composite modification layer;

[0027] The conductive polymer layer is attached to the substrate support layer to form a conductive coating.

[0028] The composite modified layer is attached to the upper surface of the conductive coating;

[0029] The composite modified layer material includes buffer solution, dopamine hydrochloride, and sodium alginate.

[0030] This invention also provides a membrane treatment device based on a wettability-controlled conductive composite membrane, comprising: a filter chamber, the aforementioned conductive composite membrane, a DC power supply, an auxiliary electrode, an air pump, and a liquid level controller;

[0031] The filter chamber is provided with an inlet, an aeration port and an outlet; the inlet is connected to an inlet pipe, the aeration port is located at the lower part of the side wall of the filter chamber, and the outlet is used to discharge the liquid after membrane filtration.

[0032] The conductive composite membrane is fixed in the middle of the filter cavity and connected to the negative terminal of the DC power supply through a wire;

[0033] The auxiliary electrode is fixed on the inner wall of the filter cavity, and its positive electrode is connected to the positive electrode of the DC power supply through a wire.

[0034] The air pump is connected to the aeration port and delivers air bubbles to the surface of the conductive composite membrane.

[0035] The probe of the liquid level controller is fixed to the top of the filter chamber and linked with the water inlet to control the liquid level in the filter chamber to permeate the conductive composite membrane.

[0036] The beneficial effects of this invention include: the wettability-controlled conductive composite membrane preparation method provided in this embodiment involves adding a nitrogen-containing heterocyclic compound to an oxidant solution under ice bath conditions to obtain a conductive solution. Then, a substrate support layer is immersed in the conductive solution to obtain a conductive polymer layer. Finally, the conductive polymer layer is immersed in a hydrophilic modification solution prepared by mixing dopamine hydrochloride and sodium alginate, and statically impregnated at room temperature to form a conductive composite membrane. This conductive composite membrane has strong detergency, effectively inhibiting membrane fouling, including complex pollutant contamination. Furthermore, it exhibits slow flux decay, simple and effective cleaning, and high recovery rate. Further, the membrane treatment device using this conductive composite membrane as a core component has a simple structure, low energy consumption, in-situ self-cleaning capability, convenient disassembly and cleaning, low maintenance costs, and is applicable to various water treatment scenarios, including small and medium-sized water treatment scenarios. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of a method for preparing a wettability-controlled conductive composite film according to an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of a membrane treatment device based on a wettability-controlled conductive composite membrane provided in an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of the working process of a membrane treatment device based on a conductive composite membrane with wettability regulation, provided for an embodiment of the present invention. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0041] This invention provides a method for preparing a wettability-controlled conductive composite film, such as... Figure 1 As shown, it includes:

[0042] S1. Prepare the oxidizing agent solution;

[0043] Specifically, under ice bath conditions, an oxidant is added to deionized water to prepare an oxidant solution with a concentration of 0.2 mol / L to 1 mol / L. The oxidant can be... Ferric chloride hexahydrate, or APS (Ammonium Persulfate), or KPS (Potassium Persulfate), are used. The specific compounds of the oxidant are not limited in the embodiments of the present invention.

[0044] In this embodiment of the invention, 8.11g of [unclear text - possibly a product name or ingredient] was placed under ice bath conditions (0℃-5℃). Slowly dissolve in 100 mL of deionized water (conductivity ≤ 10 μS / cm) to prepare a 0.6 mol / L oxidant solution. Stir magnetically (300 r / min) until completely dissolved to obtain the oxidant solution.

[0045] S2. Under ice bath conditions, a nitrogen-containing heterocyclic compound is added to the oxidant solution to obtain a conductive solution;

[0046] The nitrogen-containing heterocyclic compound can be a pyrrole monomer, or thiophene, or indole, or aniline. In this embodiment of the invention, the pyrrole monomer, purified by distillation, is added dropwise under ice bath conditions and stirred until homogeneous to obtain a conductive solution.

[0047] Specifically, 5.71 mL of distilled and purified pyrrole monomer (analytical grade, purity ≥99%) was added dropwise to the above oxidant solution. The molar ratio of oxidant to monomer was 3:1. After adding the pyrrole monomer, the mixture was stirred continuously for 30 min to prepare a 0.2 mol / L light brown conductive solution. This process was carried out under ice bath conditions because ice bath conditions can inhibit the self-polymerization of pyrrole monomer and avoid uneven coating.

[0048] S3. Immerse the substrate support layer in the conductive solution to obtain a conductive polymer layer;

[0049] It should be noted that the substrate support layer can be a PVDF (Polyvinylidene Fluoride) microfiltration membrane with a pore size of 0.1μm-0.5μm and a porosity of 65%-75%, or it can be a ceramic membrane with a pore size of 0.2μm-0.3μm. The specific material of the substrate support layer is not limited in the embodiments of the present invention, as long as it is suitable for high temperature or highly corrosive wastewater scenarios and has sufficient mechanical strength.

[0050] In this embodiment of the invention, the substrate support layer is selected as 47mm PVDF with a membrane pore size of 0.2μm, a porosity of 70%, and a thickness of 120μm. The PVDF microfiltration membrane is then enlarged using a hot-press splicing method, with the splicing temperature controlled at 120℃, pressure at 0.1MPa, and held at the same temperature and pressure for 30 seconds. It is then cut into circular membrane sheets with a diameter of 22.5cm, ensuring that the edges of the substrate support layer are free of burrs and damage.

[0051] Before immersing the substrate support layer in the conductive solution, the substrate support layer can be pretreated to improve the filtration effect. This embodiment of the invention uses a PVDF microfiltration membrane as an example; the pretreatment of the substrate support layer includes:

[0052] The cut PVDF microfiltration membrane was completely immersed in 500 mL of anhydrous ethanol and then ultrasonically cleaned for 15 minutes at a power of 100 W and a frequency of 40 kHz. Ultrasonic cleaning removes residual production aids, such as plasticizers, from the membrane surface. It was then ultrasonically cleaned with deionized water to remove any remaining ethanol. The cleaning process can be repeated three times, 10 minutes each time. After the final cleaning, the conductivity of the rinsing solution was measured to ensure it was ≤10 μS / cm, confirming complete removal of any remaining ethanol.

[0053] The cleaned PVDF microfiltration membrane was placed in a plasma cleaner for plasma activation. Argon gas was introduced and the flow rate was controlled at 20 sccm. The vacuum degree was maintained at 0.08 MPa and the treatment time was 3 minutes. This process generated active groups such as hydroxyl (-OH) and carboxyl (-COOH) on the surface of the PVDF membrane, which improved the adhesion of the subsequent polypyrrole coating.

[0054] The PVDF microfiltration membrane, after being treated by a plasma cleaner, was placed in a vacuum drying oven and dried for 2 hours at 40°C and a vacuum degree ≤10Pa. After drying, it was sealed and placed in a desiccator for later use to avoid moisture absorption that could affect the subsequent polymerization reaction.

[0055] The substrate support layer is immersed in the conductive solution to obtain a conductive polymer layer, specifically comprising:

[0056] S31. Under ice bath conditions, the substrate support layer is immersed in the conductive solution, and after standing, a polymer film is obtained.

[0057] The pretreated PVDF microfiltration membrane was completely immersed in the conductive solution and statically polymerized at 0℃-5℃ for 2h-4h, resulting in a polymer membrane thickness of 5μm-10μm.

[0058] S32. After rinsing the polymer film with deionized water, place it in a vacuum drying oven for drying to obtain a conductive polymer layer.

[0059] The polymer film obtained in the previous step is removed and rinsed with deionized water until the rinsing solution is colorless to remove unreacted monomers and... The residue was then placed in a vacuum drying oven and dried at 50°C for 3 hours to obtain a uniform black conductive polymer layer.

[0060] S4. Prepare a hydrophilic modified solution by mixing dopamine hydrochloride and sodium alginate, specifically including:

[0061] S41. Dissolve dopamine hydrochloride in buffer solution to obtain dopamine solution;

[0062] In this embodiment of the invention, dopamine hydrochloride (analytical grade, purity ≥98%) was dissolved in Tris-HCl (Tris(hydroxymethyl)aminomethane hydrochloride) (pH=8.5, concentration 10mmol / L) buffer solution and stirred until completely dissolved.

[0063] S42. Add sodium alginate to the dopamine solution to obtain a hydrophilic modified solution:

[0064] Sodium alginate powder was added to the dopamine solution prepared above and stirred continuously for 30-90 minutes (300 rpm) to form a uniform pale yellow solution. After standing for 15 minutes to remove bubbles, a hydrophilic modified solution was obtained. The concentration of dopamine hydrochloride was controlled at 1 mg / mL-5 mg / mL, and the concentration of sodium alginate was 2 mg / mL-6 mg / mL. In this embodiment of the invention, the concentration of dopamine hydrochloride was 2 mg / mL, and the concentration of sodium alginate was 4 mg / mL.

[0065] S5. The conductive polymer layer is immersed in the hydrophilic modification liquid and statically impregnated at room temperature to form a conductive composite film.

[0066] With the conductive layer of the conductive polymer layer facing upwards, it is completely immersed in a hydrophilic modification solution and statically immersed at room temperature (25°C) for 30-60 minutes. Dopamine hydrochloride self-polymerizes on the surface of the conductive polymer layer to form a polydopamine film. At the same time, sodium alginate binds to the polydopamine film through hydrogen bonds, resulting in a conductive composite film with a thickness of 3μm-5μm.

[0067] Furthermore, after forming the conductive composite film, it also includes:

[0068] The conductive composite film was rinsed with deionized water to remove unbonded modifiers from the surface, and then immersed in calcium chloride ( Crosslinking was performed in a 0.1 mol / L solution for 10 min, via... Coordination bonds are formed with the carboxyl groups of sodium alginate to improve the mechanical stability and erosion resistance of the composite modified layer; the cross-linked film is placed in a vacuum drying oven and dried at 35°C for 2 hours to avoid damage to the hydrophilic groups caused by high temperature.

[0069] This invention also provides a conductive composite film 12 prepared according to the above method, comprising: a substrate support layer, a conductive polymer layer, and a composite modification layer;

[0070] The conductive polymer layer is attached to the substrate support layer to form a conductive coating.

[0071] The composite modified layer is attached to the upper surface of the conductive coating;

[0072] The composite modified layer includes a buffer solution, dopamine hydrochloride, and sodium alginate.

[0073] See Figure 2 The present invention also provides a membrane treatment device based on a wettability-controlled conductive composite membrane, comprising: a filter chamber 11, the aforementioned conductive composite membrane 12, a DC power supply 13, an auxiliary electrode 14, an air pump 15, and a liquid level controller 16.

[0074] The filter chamber 11 is provided with an inlet, an aeration port and an outlet; the inlet is connected to an inlet pipe, the aeration port is located at the lower part of the side wall of the filter chamber, and the outlet is used to discharge the liquid after membrane filtration.

[0075] In this embodiment of the invention, the filter chamber 11 is made of a 10mm thick transparent acrylic sheet, which facilitates observation of the conductive composite membrane 12. It is then bonded together using plexiglass adhesive, and silicone sealant is applied to the seams to ensure no leakage. The filter chamber 11 has a simple structure, no complex internal components, and is easy to disassemble and clean, making it suitable for small to medium-sized applications (processing capacity of 5L / h-10L / h).

[0076] In practical applications, a drain can also be provided at the bottom of the filter chamber 11 to clean up a small amount of sediment, which is mainly suspended particulate matter that has not been adsorbed by the auxiliary electrode.

[0077] In this embodiment of the invention, the filter chamber 11 has a total height of 350mm, an inner diameter of 220mm, and a wall thickness of 10mm. The water inlet is located 50mm to the left of the top center of the filter chamber 11, and the water outlet is located at the bottom center of the filter chamber 11. Both use G1 / 2 threaded interfaces for easy pipe connection. The aeration port is located on the left side wall of the filter chamber 11, 50mm below the installation position of the conductive composite membrane 12, with an interface diameter of 15mm and equipped with a rubber sealing ring to prevent air leakage. The drain port is located on the bottom left side of the filter chamber 11, 20mm from the bottom, with an interface diameter of 15mm and equipped with a manual valve for draining.

[0078] The conductive composite membrane 12 is fixed in the middle of the filter cavity 11 and connected to the negative terminal of the DC power supply 13 through a wire.

[0079] In practical applications, the water contact angle of the conductive composite membrane 12 is ≤15°, which can significantly reduce the adsorption and adhesion of pollutants.

[0080] In this embodiment of the invention, the DC power supply 13 is a low-voltage safe power supply (0.3V-1V) with extremely low energy consumption (≤0.05W), which can avoid the generation of byproducts such as ozone; the negative electrode is connected to the conductive polymer layer of the conductive composite membrane, and the positive electrode is connected to the annular auxiliary electrode, forming a uniform weak electric field in the raw water cavity, promoting the migration of charged pollutants (such as colloidal and ionic organic matter) and preventing them from accumulating on the membrane surface.

[0081] The auxiliary electrode 14 is fixed on the inner wall of the filter cavity 11, and its positive electrode is connected to the positive electrode of the DC power supply 13 through a wire.

[0082] In this embodiment of the invention, the auxiliary electrode 14 is made of annular titanium mesh with a mesh size of 80-100 mesh. The diameter of the annular titanium mesh is cut to match the inner diameter of the filter cavity 11. After cutting, its surface is sandblasted (50μm particle size) to increase the specific surface area and improve the uniformity of the electric field. Then, it is soaked in dilute hydrochloric acid (5wt%) for 10 minutes to remove the surface oxide film, rinsed with deionized water, and dried to obtain the annular auxiliary electrode. The auxiliary electrode 14 is then fixed to the inner wall of the filter cavity 11 through the slot, with a distance of 5cm-8cm between it and the conductive composite membrane 12 to ensure uniform electric field distribution and not affect water flow and bubble flow.

[0083] The air pump 15 is connected to the aeration port and delivers air bubbles to the surface of the conductive composite membrane 12.

[0084] In this embodiment of the invention, the air pump 15 is a diaphragm-type micro air pump (power ≤ 5W), with an output air pressure of 0.02MPa-0.05MPa. It is equipped with an airflow regulating valve and an air bubble stone (pore size 100μm). The air is dispersed into microbubbles of 50μm-200μm through the air bubble stone. When the air bubbles are delivered to the surface of the conductive composite membrane 12, the surface of the conductive composite membrane 12 is physically scourned during the rising process of the air bubbles, and the small amount of adsorbed pollutants are removed. No chemical cleaning agent is required, and in-situ self-cleaning is achieved.

[0085] In operation, the air pump 15 is controlled by a timer to run for 30 seconds to 1 minute and stop for 5 minutes to 10 minutes. This can be adjusted according to the turbidity of the raw water. For example, when the turbidity is >50 NTU, the running time is extended to 1 minute and the stopping time is shortened to 5 minutes.

[0086] The probe of the liquid level controller 16 is fixed to the top of the filter chamber 11 and linked with the water inlet. The probe monitors and controls the liquid level in the filter chamber 11 to permeate the conductive composite membrane 12.

[0087] In this embodiment of the invention, the probe of the liquid level controller 16 is 30mm from the top and is linked with the water inlet to control the surface of the conductive composite membrane 12 to be 80mm-120mm above the water surface. In other words, it ensures that the conductive composite membrane 12 is always covered by water, thus avoiding the aggravation of pollution caused by the drying of the conductive composite membrane 12.

[0088] Figure 3 This is a schematic diagram of the working process of a membrane treatment device based on a conductive composite membrane with wettability regulation provided in an embodiment of the present invention. The membrane treatment device is assembled in the following order: "inlet → upper chamber of filter cavity → conductive composite membrane → lower chamber of filter cavity → outlet". The conductive composite membrane is sealed and fixed in the middle of the cavity (180mm from the bottom) by a flange and rubber gasket to ensure no water leakage.

[0089] After the auxiliary electrode 14 is fixed in place by the slot, the wire is passed through the pre-reserved sealing hole (sealed with silicone plug) on ​​the side wall of the filter chamber 11. The positive terminal is connected to the positive terminal of the DC power supply 13, and the conductive polymer layer of the conductive composite film 12 is connected to the negative terminal of the DC power supply 13 through the wire. The power supply output voltage is controlled to be 0.6V and the rated current is 30mA.

[0090] The micro air pump is sealed to the aeration port through a food-grade hose (15mm inner diameter). A bubble stone with a 100μm pore size is installed inside the aeration port to disperse air into microbubbles of 80μm-150μm. The liquid level controller probe is fixed at the top of the original water chamber, 30mm from the top, and is linked with the water inlet to maintain a water depth of 100mm on the membrane surface.

[0091] The working principle of this membrane treatment device is as follows: raw water enters the upper chamber of the filter chamber through the inlet, and the liquid level controller maintains the water depth on the membrane surface at 80mm-120mm. Under the action of gravity and weak hydraulic pressure difference, the water flows into the membrane surface of the conductive composite membrane.

[0092] The surface of the conductive composite membrane allows water molecules to spread and penetrate rapidly, while pollutants are suspended in the aqueous phase due to "steric hindrance + hydration repulsion". At the same time, a weak electric field is activated. The membrane surface of the conductive composite membrane is connected to the negative terminal of the DC power supply, and the auxiliary electrode is connected to the positive terminal of the DC power supply, forming a uniform electric field from "auxiliary electrode to membrane surface". Under the action of the electric field force (the direction of the force is opposite to the electric field lines), the negatively charged pollutants in the water migrate directionally towards the auxiliary electrode, thus preventing the diffusion and adsorption of pollutants to the membrane surface of the conductive composite membrane from the source.

[0093] A micro air pump intermittently delivers microbubbles to the surface of the conductive composite membrane. The bubbles form an "air film effect" on the surface of the conductive composite membrane, further hindering the adhesion of pollutants. At the same time, the shear force of the rising bubbles washes the surface of the conductive composite membrane, peeling off a small amount of adsorbed pollutants. The pollutants float or sink to the bottom of the filter chamber with the bubbles and are cleaned through the bottom drain port.

[0094] After being filtered and purified by the conductive composite membrane, the wastewater passes through the wastewater chamber and is discharged from the outlet of the filter chamber, achieving simultaneous wastewater purification and self-cleaning of the conductive composite membrane.

[0095] To further ensure that the membrane treatment device is free from leakage, short circuits, and airflow blockage, after the membrane treatment device is assembled, the sealing of each interface, the stability of the circuit connection, and the unobstructed airflow are checked.

[0096] After inspection, the membrane treatment device can be tested. The test is conducted at room temperature (25℃) without additional heating or cooling, relying on the natural hydraulic pressure difference (approximately 0.01MPa) to drive water flow permeation. The micro air pump adopts an intermittent aeration mode, with a set running time of 45s and a stop time of 8min, and a bubble output of 0.8L / min. The microbubbles generated by the air stone are evenly distributed below the membrane surface, achieving physical scouring of the conductive composite membrane surface.

[0097] After the test is completed, the membrane treatment device can be tested. During the experiment, samples were taken at 0h (initial state), 6h, 12h, 24h, 48h, and 72h of operation. The influent sample was taken from the inlet of the filter chamber, and the effluent sample was taken from the outlet. The parameters such as COD (Chemical Oxygen Demand), turbidity, and SS (Suspended Solids) were tested using a water quality analyzer according to the corresponding national standard methods.

[0098] The initial membrane flux, tested using a full-capacity filtration unit, was 85 L / (m²·h). After 6 hours of operation, the membrane flux was 82 L / (m²·h), with a retention rate of 96.5%. After 12 hours of operation, the membrane flux was 79 L / (m²·h), with a retention rate of 92.9%. After 24 hours of operation, the membrane flux was 75 L / (m²·h), with a retention rate of 88.2%. Water quality testing results showed that after 24 hours of operation, the effluent COD was 45 mg / L, with a removal rate of 83.9%; turbidity was 3.2 NTU, with a removal rate of 92.9%; and SS was 8 mg / L, with a removal rate of 93.3%. All indicators met the Class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB 18918-2002). After 72 hours of continuous operation, the membrane flux remained at 66 L / (m²·h), a retention rate of 77.6%. During this period, only a small amount of deposits needed to be cleaned through the drain port at the bottom of the filter chamber. The deposits mainly consisted of suspended particulate matter not adsorbed by the auxiliary electrode. Observing the surface of the conductive composite membrane after opening the filter chamber revealed no obvious fouling layer. After rinsing with deionized water for 1 minute, the membrane flux recovered to 81 L / (m²·h), a recovery rate of 95.3%. This demonstrates that the triple synergistic self-cleaning mechanism of the membrane treatment device effectively inhibits membrane fouling and maintains stable operation without the need for chemical cleaning.

[0099] The wettability-controlled conductive composite membrane preparation method provided in this invention involves adding a nitrogen-containing heterocyclic compound to an oxidant solution under ice bath conditions to obtain a conductive solution. A substrate support layer is then immersed in the conductive solution to obtain a conductive polymer layer. Finally, the conductive polymer layer is immersed in a hydrophilic modification solution prepared from a mixture of dopamine hydrochloride and sodium alginate, and statically impregnated at room temperature to form a conductive composite membrane. This conductive composite membrane exhibits strong detergency, effectively inhibiting membrane fouling, including complex contaminant fouling. Furthermore, it shows slow flux decay, simple and effective cleaning, and high membrane flux recovery rate. Moreover, the membrane treatment device using this conductive composite membrane as a core component has a simple structure, low energy consumption, in-situ self-cleaning capability, convenient disassembly and cleaning, low maintenance costs, and is applicable to various water treatment scenarios, including small and medium-sized water treatment applications.

[0100] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a wettability-controlled conductive composite film, characterized in that, include: Preparation of oxidant solution; The oxidant is ferric chloride hexahydrate, ammonium persulfate, or potassium persulfate; Under ice bath conditions, pyrrole monomer is added to the oxidant solution to obtain a conductive solution; The substrate support layer is immersed in the conductive solution to obtain a conductive polymer layer; A hydrophilic modified solution was prepared by mixing dopamine hydrochloride and sodium alginate. The conductive polymer layer is immersed in the hydrophilic modified liquid and statically impregnated at room temperature to form a conductive composite film. The thickness of the conductive composite film is 3μm-5μm; After rinsing the conductive composite membrane with deionized water, it is immersed in calcium chloride solution and allowed to stand. The conductive composite film, after being left to stand, is placed in a vacuum drying oven for drying.

2. The method according to claim 1, characterized in that, Adding pyrrole monomer to the oxidant solution to obtain a conductive solution includes: Add the purified pyrrole monomer dropwise and stir until homogeneous to obtain a conductive solution.

3. The method according to claim 1, characterized in that, The substrate support layer is immersed in the conductive solution to obtain a conductive polymer layer, comprising: Under ice bath conditions, the substrate support layer is immersed in the conductive solution and allowed to stand for polymerization to obtain a polymer film; The polymer film was rinsed with deionized water and then dried in a vacuum drying oven to obtain a conductive polymer layer.

4. The method according to claim 3, characterized in that, The ice bath conditions are 0℃-5℃, the static polymerization time is 2h-4h, and the thickness of the polymer film is 5μm-10μm.

5. The method according to claim 1, characterized in that, A hydrophilic modified solution was prepared by mixing dopamine hydrochloride and sodium alginate, comprising: Dopamine hydrochloride was dissolved in a buffer solution to obtain a dopamine solution; Sodium alginate was added to the dopamine solution to obtain a hydrophilic modified solution.

6. The method according to claim 5, characterized in that, Sodium alginate was added to the dopamine solution to obtain a hydrophilic modified solution, specifically: Sodium alginate powder was added to the dopamine solution and stirred continuously for 30-90 minutes, then allowed to stand to remove bubbles to obtain a hydrophilic modified solution; wherein the concentration of dopamine hydrochloride was controlled at 1 mg / mL-5 mg / mL, and the concentration of sodium alginate was 2 mg / mL-6 mg / mL.

7. A conductive composite film prepared according to claim 1, characterized in that, include: Substrate support layer, conductive polymer layer and composite modification layer; The conductive polymer layer is attached to the substrate support layer to form a conductive coating. The composite modified layer is attached to the upper surface of the conductive coating; The composite modified layer material includes buffer solution, dopamine hydrochloride, and sodium alginate.

8. A membrane treatment device based on a wettability-controlled conductive composite membrane, characterized in that, include: The filter chamber, the conductive composite membrane as described in claim 7, the DC power supply, the auxiliary electrode, the air pump, and the liquid level controller; The filter chamber is provided with an inlet, an aeration port and an outlet; the inlet is connected to an inlet pipe, the aeration port is located at the lower part of the side wall of the filter chamber, and the outlet is used to discharge the liquid after membrane filtration. The conductive composite membrane is fixed in the middle of the filter cavity and connected to the negative terminal of the DC power supply through a wire; The auxiliary electrode is fixed on the inner wall of the filter cavity, and its positive electrode is connected to the positive electrode of the DC power supply through a wire. The air pump is connected to the aeration port and delivers air bubbles to the surface of the conductive composite membrane. The probe of the liquid level controller is fixed to the top of the filter chamber and linked with the water inlet. The probe monitors and controls the liquid level in the filter chamber to permeate the conductive composite membrane.

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