Double intelligent response and closed-loop control polyether sulfone hollow fiber membrane module and preparation method thereof

Abstract

The invention discloses a double intelligent response and closed-loop control polyethersulfone hollow fiber membrane module and a preparation method thereof.The module comprises a membrane filament bundle, an intelligent control system, a transparent shell, an end cover and an inlet and outlet interface, the membrane filament bundle is composed of a plurality of polyethersulfone hollow fiber membrane filaments, and the inner surfaces of the membrane filaments are grafted with temperature response polymers; an inner surface temperature response layer is formed, a pH response polymer is grafted on the outer surface, an outer surface pH response layer is formed, a dual intelligent response layer with inner and outer partition and function synergy is formed, an independently anchored gradient transition layer is arranged between the response layer and the membrane substrate, and the polymer density of the gradient transition layer is gradually reduced from the membrane surface to the interior of the membrane substrate. The intelligent control system is used for anchoring the response layer on the surface of a base body to enhance the binding force and prevent falling off, integrates a temperature sensor, a pH sensor, a microprocessor and an electric heating element to form a closed-loop control loop, and can adjust the performance of the film in a real-time and self-adaptive mode according to feeding conditions.

Description

Technical Field

[0001] This invention relates to the field of membrane separation technology, and in particular to a polyethersulfone hollow fiber membrane module with dual intelligent response and closed-loop control and its preparation method. Specifically, it relates to a polyethersulfone hollow fiber membrane module with dual intelligent response and closed-loop control and its preparation method. Background Technology

[0002] Polyethersulfone hollow fiber membranes are widely used in hemodialysis, industrial water treatment and bioseparation due to their excellent mechanical strength, thermal stability and chemical resistance. However, traditional polyethersulfone membranes have problems such as strong surface hydrophobicity, susceptibility to fouling by organic matter such as proteins, and fixed water flux and rejection rate. When dealing with complex material systems or materials with dynamic changes in composition, traditional membranes cannot adaptively adjust their separation performance, resulting in decreased efficiency and aggravated membrane fouling.

[0003] To address these issues, existing technologies typically employ blending modification or surface grafting to introduce hydrophilic or functionalized polymers. In recent years, smart responsive polymers (such as temperature-sensitive and pH-sensitive polymers) have been grafted onto membrane surfaces, enabling membranes to possess a certain degree of environmental responsiveness. However, most current research focuses on single response mechanisms (temperature or pH only), which are insufficient to handle the complex environments with multiple coupled changes in practical applications. Furthermore, existing smart responsive membranes are mostly confined to the material level, lacking a systematic design that integrates with sensing and actuation units, thus failing to achieve real-time, closed-loop, and precise control of the separation process. Some membrane modules that attempt integrated control also suffer from problems such as single response signals, lag in regulation, uneven heating of the membrane surface, and easy detachment of the response layer. Therefore, developing a smart membrane separation module that can simultaneously respond to multiple environmental signals, has real-time dynamic performance optimization, and is stable and reliable has become a pressing technical challenge in this field. Summary of the Invention

[0004] The main objective of this invention is to overcome the shortcomings of existing technologies and provide a polyethersulfone hollow fiber membrane module with dual intelligent response and closed-loop control, as well as its preparation method. This approach achieves coordinated and adaptive regulation of membrane pore size and surface charge by constructing different types of intelligent response layers on the inner and outer surfaces of the membrane fibers and integrating an advanced closed-loop control system. This significantly improves the membrane's separation efficiency, selectivity, and antifouling ability under dynamic conditions.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A polyethersulfone hollow fiber membrane module with dual intelligent response and closed-loop control and its preparation method are disclosed, comprising a membrane fiber bundle, an intelligent control system, a transparent shell, end caps, and inlet / outlet interfaces. The membrane fiber bundle is composed of multiple polyethersulfone hollow fiber membrane fibers. Its core innovation lies in the grafting of temperature-responsive polymers (such as PNIPAM or PNVCL) onto the inner surface of the membrane fibers and pH-responsive polymers (such as PDMAEMA or PAA) onto the outer surface, forming a dual intelligent response layer with internal and external partitioning and functional synergy. Between the response layer and the membrane substrate, there is an independent anchoring gradient transition layer formed by copolymerization of temperature-responsive and pH-responsive polymers with gradually decreasing polymer density from the membrane surface to the interior of the membrane substrate. This layer is used to anchor the response layer to the substrate surface, enhance the bonding force, and prevent detachment. The intelligent control system integrates a temperature sensor, a pH sensor, a microprocessor, and an electrothermal element to form a closed-loop control circuit. It can adjust the membrane working state in real time according to the feed conditions. The microprocessor has a preset control algorithm to dynamically adjust the power of the electrothermal element based on the real-time monitored temperature and pH signals. The inner wall of the transparent shell is provided with a reflective coating, and the electrothermal element adopts a transparent conductive film or metal mesh to achieve uniform heating and process visualization.

[0007] The temperature-responsive polymer PNIPAM used in this invention undergoes a reversible stretching / collapse transition in its molecular chain around 32°C. This process, driven by the formation and breaking of hydrogen bonds, is a recognized temperature-responsive mechanism in polymer science. Similarly, the tertiary amine groups of the pH-responsive polymer PDMAEMA undergo reversible protonation / deprotonation in the pH range of 6.0-8.0, leading to changes in chain conformation and surface charge, which has also been verified through extensive experiments. These two mechanisms are independent and do not interfere with each other, providing a solid scientific basis for the simultaneous regulation of the dual responses in this invention.

[0008] The present invention is further configured to include four steps: preparation of polyethersulfone hollow fiber base membrane, preparation of independently anchored gradient transition layer and dual response layer on membrane fiber surface, assembly of intelligent control system, and overall assembly of membrane module.

[0009] The present invention is further configured to: prepare the base film using a dry-wet spinning method, modify the surface of the film fibers using the ATRP or RAFT method, and prepare an independently anchored gradient transition layer and a dual smart response layer.

[0010] The present invention is further configured such that the specific steps for preparing the polyethersulfone hollow fiber-based membrane are as follows:

[0011] S1.1 Using polyethersulfone as the membrane material, and one or a mixture of two or more solvents such as N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF) as the solvent, a pore-forming agent (such as polyethylene glycol or polyvinylpyrrolidone) is added, and the mixture is stirred and dissolved at 45-95°C to form a casting solution with a mass fraction of 15-25%.

[0012] S1.2. The casting solution is extruded through a spinneret and spun using a dry-wet spinning method. The dry spinning distance is controlled to be 0.1-15 cm, the coagulation bath temperature is room temperature-99℃, and the coagulation bath is a mixture of water and one or more of the following solvents (N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF) as solvents (concentration 5-70%). The traction speed is 1-3 m / min to prepare a polyethersulfone hollow fiber base membrane.

[0013] S1.3 Soak the base film in deionized water for 24-48 hours to remove residual solvents and pore-forming agents, then air dry for later use.

[0014] The present invention is further configured such that the specific steps for preparing the independently anchored gradient transition layer and the dual-response layer on the surface of the membrane fiber are as follows:

[0015] S2.1 The polyethersulfone hollow fiber membrane is surface modified by atom transfer radical polymerization or reversible addition-fragmentation chain transfer polymerization.

[0016] S2.2 Activation treatment of the base membrane: Immerse the base membrane in a dopamine solution with a concentration of 1-3 mg / mL, adjust the pH of the solution to 8.5 with Tris-HCl buffer, and soak at 25-35℃ for 12-24 hours to form a polydopamine coating on the surface of the base membrane.

[0017] S2.3 Preparation of Independent Anchored Gradient Transition Layer: The activated base membrane is bundled and sealed at both ends with epoxy resin inside end caps to ensure airtightness, forming the membrane fiber core. The membrane fiber core is then installed into the outer shell, and the end caps and the outer shell are sealed with rubber rings. First, a mixed reaction solution containing temperature-responsive monomers, initiators, and catalysts is slowly circulated on the inner surface of the membrane fibers, and then a mixed reaction solution containing pH-responsive monomers, initiators, and catalysts is slowly circulated on the outer surface of the membrane fibers. The reaction temperature is controlled at 45-85℃, and the reaction time is 6-12 hours. By adjusting the monomer concentration and reaction kinetics, the temperature-responsive polymer and the pH-responsive polymer are copolymerized on the membrane surface to form an independent anchored gradient transition layer with a polymer density that gradually decreases from the surface to the interior, with a thickness of 0.5-2 μm.

[0018] S2.4 Preparation of Dual Smart Response Layers: In the reaction system of step S2.3, add the corresponding temperature-responsive monomers and pH-responsive monomers. By controlling the reaction conditions, the temperature-responsive polymer is selectively grafted onto the inner surface of the membrane fiber to form a temperature-responsive layer, and the pH-responsive polymer is selectively grafted onto the outer surface of the membrane fiber to form a pH-responsive layer. After the reaction is complete, remove the membrane fiber core, cut off the portion of the membrane fiber encapsulated in epoxy resin, thoroughly rinse the membrane fiber with deionized water to remove unreacted monomers and homopolymers, and air dry to obtain the dual smart response membrane fiber.

[0019] The present invention is further configured such that the specific assembly steps of the intelligent control system are as follows:

[0020] S3.1 Embed the temperature sensor and pH sensor inside the membrane module end cap to ensure that their probes can fully contact the feed fluid;

[0021] S3.2 Fix the microprocessor to the outside of the end cap and connect it to the sensor and the heating element (transparent conductive film or metal mesh) through wires;

[0022] S3.3 Spray a reflective coating onto the inner wall of the transparent housing, and then attach the heating element (transparent conductive film or metal mesh) to the inner wall;

[0023] S3.4 Connect and debug each component to ensure accurate sensor signal transmission, effective microprocessor control logic, and uniform heating of the heating element.

[0024] The present invention is further configured such that the specific steps for the overall assembly of the membrane module are as follows:

[0025] S4.1 Arrange the prepared dual-intelligent responsive polyethersulfone hollow fiber membrane fibers into bundles, and encapsulate both ends with epoxy resin in the end caps to ensure airtightness;

[0026] S4.2 Seal the end cap of the encapsulated membrane fiber bundle to the transparent shell, and install the inlet, product water outlet and concentrate outlet;

[0027] S4.3 Connect the assembled intelligent control system to the membrane module body via electrical and mechanical means;

[0028] S4.4 Perform airtightness testing and performance debugging on the fully assembled membrane module to ensure that it meets the design requirements.

[0029] The present invention is further configured such that: the temperature-responsive polymer is PNIPAM or PNVCL, which undergoes a phase transition at 28-35℃, and the membrane pore size changes reversibly by ±30-50%; the pH-responsive polymer is PDMAEMA or PAA, which undergoes protonation / deprotonation at pH 6.0-8.0, and the surface charge changes reversibly by ±20-40mV.

[0030] The present invention is further configured such that: the thickness of the independent anchoring gradient transition layer is 0.5-2μm, the polymer density gradually decreases from the membrane surface to the interior, and the gradient structure is formed by copolymerization of two responsive polymers, which can significantly enhance the bonding force between the subsequently grafted responsive layer and the matrix, firmly anchor the responsive layer to the matrix surface, and prevent the shedding water flux during long-term operation from reversibly changing by ±40-60% within the range of 25-40℃.

[0031] The present invention is further configured such that: the polyethersulfone hollow fiber membrane filament has an asymmetric sponge-like pore structure, including a support layer, and an inner surface layer and an outer surface layer covering the support layer; the average pore size of the support layer is 10 to 50 times the average pore size of the inner surface layer, the average pore size of the inner surface layer is 0.027 to 0.032 μm, the inner diameter of the hollow fiber membrane is 450 to 550 μm, and the wall thickness is 200 to 300 μm.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. This invention pioneers an internal and external synergistic partitioned response mechanism: for the first time, an inner surface temperature-responsive layer and an outer surface pH-responsive layer are separately constructed on polyethersulfone hollow fiber membrane filaments. Unlike the existing technology where the upper and lower layers pass sequentially, the internal and external partitioned design of this invention allows the fluid to contact both response layers simultaneously. The inner surface temperature-sensitive layer directly regulates the flux, while the outer surface pH-sensitive layer immediately prevents pollutant adsorption through charge repulsion. The two functions work simultaneously and synergistically, significantly improving the overall separation efficiency and antifouling capability of the membrane.

[0034] 2. Excellent interfacial bonding stability: By introducing an independent anchoring gradient transition layer formed by copolymerization of two responsive polymers between the response layer and the substrate membrane, the polymer density of this gradient layer gradually decreases from the surface to the interior, allowing the material properties to gradually transition from the hydrophobic matrix to the hydrophilic response layer, eliminating obvious interfaces and alleviating stress concentration. Simultaneously, the gradient layer forms a semi-interpenetrating network with the substrate, providing abundant covalent bonding sites for the response layer, firmly anchoring it to the substrate surface. This effectively solves the problems of weak bonding and easy detachment between the response layer and the substrate, significantly improving the stability of the response speed and cycle life. Experiments show that this structure enables reversible changes in membrane water flux of ±40-60% within the range of 25-40℃, and the flux recovery rate after antifouling cleaning is significantly improved.

[0035] 3. In this invention, true closed-loop intelligent control is achieved: for the first time, temperature and pH sensors, microprocessor-based intelligent decision-making, and electrothermal actuators are deeply integrated into the membrane module, forming a complete closed-loop control circuit. The microprocessor can automatically and precisely adjust the membrane environment based on real-time monitored feed parameters through fuzzy control or neural network algorithms, achieving a leap from "passive response" to "active intelligent regulation," and solving the problems of lag and inaccuracy inherent in manual regulation.

[0036] 4. In this invention, uniform and efficient visual heating is achieved by adopting a transparent shell design and an inner wall with a reflective coating and a transparent conductive film / metal mesh heating element. This not only enables visual monitoring of the internal operating status of the membrane module, but more importantly, ensures that the membrane fiber bundle is heated uniformly and efficiently, avoiding the uneven temperature field caused by traditional heating methods. This ensures the consistency of the response of all membrane fibers and improves the overall separation efficiency and reliability. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the polyethersulfone hollow fiber membrane module and its preparation method according to the present invention;

[0038] Figure 2 This is a schematic diagram of the intelligent control system of the present invention;

[0039] Figure 3 This is a schematic diagram of the polyethersulfone hollow fiber membrane module and its preparation steps according to the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] like Figure 1-3 As shown, a polyethersulfone hollow fiber membrane module with dual intelligent response and closed-loop control and its preparation method are disclosed, including a membrane fiber bundle, an intelligent control system, a transparent shell, end caps, and inlet / outlet interfaces. The membrane fiber bundle is composed of multiple polyethersulfone hollow fiber membrane fibers with special surface modifications. Each membrane fiber has a temperature-responsive layer on its inner surface and a pH-responsive layer on its outer surface, as well as an independent anchoring gradient transition layer between the response layer and the substrate.

[0042] The intelligent control system integrates a temperature sensor, a pH sensor, a microprocessor, and a heating element. The temperature and pH sensors monitor relevant parameters of the feed liquid in real time and transmit the signals to the microprocessor. The microprocessor has a preset control algorithm that calculates the required temperature adjustment based on the received signals and preset separation performance targets, and controls the operating power of the heating element (a transparent conductive film attached to the inner wall of the transparent shell). This changes the local temperature of the membrane fiber bundle, activates the temperature-sensitive response layer, and achieves dynamic adjustment of the membrane pore size, forming a complete "monitoring-decision-execution" closed loop.

[0043] The polyethersulfone hollow fiber base membrane can be prepared using a conventional dry-wet spinning process. One specific embodiment is as follows: a casting solution is prepared using 20% ​​polyethersulfone, 70% N-methylpyrrolidone, and 10% polyethylene glycol (PEG-400) by mass, and stirred at 70°C until completely dissolved and degassed. The solution is extruded through a spinneret, dry-spun at a distance of 10 cm, and then placed in a 25°C coagulation bath (water / NMP volume ratio 8:2) at a traction speed of 2 m / min. The resulting nascent fibers are soaked in deionized water for 36 hours to fully displace residual solvent, and then dried for later use.

[0044] The construction of the independently anchored gradient transition layer and dual-response layer on the surface of the membrane fibers is crucial. First, the base membrane was immersed in a 2 mg / mL dopamine solution (prepared with Tris-HCl buffer at pH 8.5) and shaken at 30°C for 18 hours to form a polydopamine activation layer on the surface. Subsequently, the activated membrane fibers were bundled together, and both ends were sealed with epoxy resin end caps to ensure a tight seal, forming the membrane fiber core. The membrane fiber core was then installed into the outer shell, and the end caps were sealed to the outer shell with rubber rings. A mixture of NIPAM monomer, initiator EBiB, and catalyst CuBr / bpy was circulated at a flow rate of 20 ml / min on the inner surface of the membrane fibers, and a mixture of DMAEMA monomer, initiator EBiB, and catalyst CuBr / bpy was circulated at a flow rate of 20 ml / min on the outer surface of the membrane fibers. The molar ratio of monomer to initiator was 80:1, and the molar ratio of catalyst to initiator was 1.5:1. The reaction was carried out at 50 °C for 9 hours, forming a 1.2 μm independent anchored gradient transition layer on the membrane surface and within the pores using the ATRP method. Subsequently, NIPAM and DMAEMA monomers were added, and the reaction continued for 6 hours. By controlling the diffusion and reaction kinetics of the monomers, NIPAM and DMAEMA were more easily grafted onto the inner and outer surfaces of the membrane fibers to form a temperature-sensitive layer and corresponding layers, respectively. After the reaction, the membrane fiber core was removed, the portion of the membrane fiber encapsulated in epoxy resin was cut off, and the membrane was thoroughly rinsed with deionized water and dried.

[0045] During assembly of the intelligent control system, miniature temperature and pH sensor probes are embedded near the feed channel of the end cap. A microprocessor (such as a microcontroller) is fixed to the outside of the end cap. A thin aluminum layer is first sprayed onto the inner wall of the transparent polycarbonate shell as a reflective coating, and then an indium tin oxide transparent conductive film is adhered to the inner wall as a heating element. Finally, all wires are connected and tested.

[0046] Working Principle: In practical applications, the fluid to be treated (such as a protein solution) enters the membrane module through the inlet. Built-in sensors monitor the fluid's temperature and pH value in real time. If the microprocessor determines that the membrane surface requires charge adjustment to mitigate fouling based on the pH signal, or that the separation accuracy needs adjustment based on the flux decay signal, it will activate the control logic. For example, when the system detects that the pH is close to the isoelectric point of proteins, which can easily lead to membrane fouling, it can fine-tune the heating power, slightly increasing the membrane fiber temperature (e.g., from 25°C to 32°C). This triggers a hydrophilic-hydrophobic phase transition in the inner surface PNIPAM layer, moderately increasing the membrane pore size. This increases the water flux while maintaining the rejection rate, flushing the membrane surface and delaying fouling. The entire process is automatically completed by a closed-loop system without manual intervention. The transparent housing allows the operator to directly observe the color changes of the membrane fibers (a characteristic of certain responsive polymers) or the fouling deposition.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A polyethersulfone hollow fiber membrane module with dual intelligent response and closed-loop control and its preparation method, comprising a membrane fiber bundle, an intelligent control system, a transparent shell, end caps, and inlet / outlet interfaces, characterized in that: The membrane bundle is composed of multiple polyethersulfone hollow fiber membrane filaments. The inner surface of the polyethersulfone hollow fiber membrane filaments is grafted with a temperature-responsive polymer to form an inner surface temperature-responsive layer, and the outer surface is grafted with a pH-responsive polymer to form an outer surface pH-responsive layer, thereby constituting a dual intelligent response layer with functional partitions on the inner and outer surfaces. An independently anchored gradient transition layer is provided between the dual intelligent response layer and the polyethersulfone membrane substrate. The polymer density of the transition layer gradually decreases from the membrane surface to the interior of the membrane substrate, which is used to anchor the response layer to the substrate surface, enhance the bonding force and prevent detachment. The intelligent control system includes a temperature sensor, a pH sensor, a microprocessor, and an electric heating element. The temperature sensor and pH sensor are used to monitor the parameters of the feed fluid in real time. The microprocessor has a preset control algorithm to receive sensor signals and dynamically adjust the power of the electric heating element according to the target separation performance. The electric heating element is used to heat the membrane fiber bundle according to the control command, thereby forming a closed-loop control loop for real-time regulation of membrane separation performance. The inner wall of the transparent shell is provided with a reflective coating, and the heating element is a transparent conductive film or metal mesh attached to the inner wall of the transparent shell.

2. The polyethersulfone hollow fiber membrane module with dual intelligent response and closed-loop control according to claim 1, and its preparation method, characterized in that: The temperature-responsive polymer is poly(N-isopropylacrylamide) or poly(N-vinylcaprolactam), the pH-responsive polymer is poly(dimethylaminoethyl methacrylate) or polyacrylic acid, the thickness of the independently anchored gradient transition layer is 0.5-2 μm, and its polymer density gradually decreases from the membrane surface to the interior of the membrane substrate.

3. The polyethersulfone hollow fiber membrane module with dual intelligent response and closed-loop control according to claim 1, and its preparation method, characterized in that: The microprocessor has a preset control algorithm, which is a fuzzy control algorithm or a neural network algorithm, used to dynamically adjust the power of the heating element based on temperature, pH signals and target separation performance.

4. A method for preparing a polyethersulfone hollow fiber membrane module with dual intelligent response and closed-loop control as described in any one of claims 1-3, characterized in that, Includes the following steps: Preparation of S1, polyethersulfone hollow fiber-based membrane; S2. Preparation of independently anchored gradient transition layer and dual response layer on the surface of membrane fibers; S3, Intelligent Control System Assembly; S4. Membrane module assembly.

5. The method according to claim 4, characterized in that, In step S1, the base film is prepared by dry-wet spinning; in step S2, the surface of the film fibers is modified by atom transfer radical polymerization or reversible addition-fragmentation chain transfer polymerization.

6. The method according to claim 4, characterized in that, The specific steps for preparing the polyethersulfone hollow fiber-based membrane in step S1 are as follows: S1.1 Using polyethersulfone as the membrane material, and one or a mixture of two or more solvents such as N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF) as the solvent, a pore-forming agent (such as polyethylene glycol or polyvinylpyrrolidone) is added, and the mixture is stirred and dissolved at 45-95°C to form a casting solution with a mass fraction of 15-25%. S1.

2. The casting solution is extruded through a spinneret and spun using a dry-wet spinning method. The dry spinning distance is controlled to be 0.1-15 cm, the coagulation bath temperature is room temperature to 99 °C, and the coagulation bath is a mixture of water and one or more of the following solvents (N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), and N,N-dimethylformamide (DMF)) (concentration 5-70%). The traction speed is 1-30 m / min to prepare a polyethersulfone hollow fiber base membrane. S1.3 Soak the base film in deionized water for 24-48 hours to remove residual solvents and pore-forming agents, then air dry for later use.

7. The method according to claim 4, characterized in that, The specific steps for preparing the independently anchored gradient transition layer and dual-response layer on the membrane fiber surface in step S2 are as follows: S2.1 The polyethersulfone hollow fiber membrane is surface modified by atom transfer radical polymerization or reversible addition-fragmentation chain transfer polymerization. S2.2 Activation treatment of the base membrane: Immerse the base membrane in a dopamine solution with a concentration of 1-3 mg / mL, adjust the pH of the solution to 8.5 with Tris-HCl buffer, and soak at 25-35℃ for 12-24 hours to form a polydopamine coating on the surface of the base membrane. S2.3 Preparation of Independent Anchored Gradient Transition Layer: The activated base membrane is bundled and sealed at both ends with epoxy resin inside end caps to ensure airtightness, forming the membrane fiber core. The membrane fiber core is then installed into the outer shell, and the end caps and the outer shell are sealed with rubber rings. First, a mixed reaction solution containing temperature-responsive monomers, initiators, and catalysts is slowly circulated on the inner surface of the membrane fibers, and then a mixed reaction solution containing pH-responsive monomers, initiators, and catalysts is slowly circulated on the outer surface of the membrane fibers. The reaction temperature is controlled at 45-85℃, and the reaction time is 6-12 hours. By adjusting the monomer concentration and reaction kinetics, the temperature-responsive polymer and the pH-responsive polymer are copolymerized on the membrane surface to form an independent anchored gradient transition layer with a polymer density that gradually decreases from the surface to the interior, with a thickness of 0.5-2 μm. S2.4 Preparation of Dual Smart Response Layer: In the reaction system of step S2.3, add the corresponding temperature-responsive monomer and pH-responsive monomer. By controlling the reaction conditions, the temperature-responsive polymer is selectively grafted onto the inner surface of the membrane fiber to form a temperature-responsive layer, and the pH-responsive polymer is selectively grafted onto the outer surface of the membrane fiber to form a pH-responsive layer. After the reaction is completed, the membrane fiber core is extracted, the part of the membrane fiber encapsulated in epoxy resin is cut off, the membrane fiber is thoroughly rinsed with deionized water to remove unreacted monomers and homopolymers, and after drying, the dual smart response membrane fiber is obtained.

8. The method according to claim 4, characterized in that, The specific steps for assembling the intelligent control system described in step S3 are as follows: S3.1 Embed the temperature sensor and pH sensor inside the membrane module end cap to ensure that their probes can fully contact the feed fluid; S3.2 Fix the microprocessor to the outside of the end cap and connect it to the sensor and the heating element (transparent conductive film or metal mesh) through wires; S3.3 Spray a reflective coating onto the inner wall of the transparent housing, and then attach the heating element (transparent conductive film or metal mesh) to the inner wall; S3.4 Connect and debug each component to ensure accurate sensor signal transmission, effective microprocessor control logic, and uniform heating of the heating element.

9. The method according to claim 4, characterized in that, The specific steps for assembling the membrane module in step S4 are as follows: S4.1 Arrange the prepared dual-intelligent responsive polyethersulfone hollow fiber membrane fibers into bundles, and encapsulate both ends with epoxy resin in the end caps to ensure airtightness; S4.2 Seal the end cap of the encapsulated membrane fiber bundle to the transparent shell, and install the inlet, product water outlet and concentrate outlet; S4.3 Connect the assembled intelligent control system to the membrane module body via electrical and mechanical means; S4.4 Perform airtightness testing and performance debugging on the fully assembled membrane module to ensure that it meets the design requirements.

10. The polyethersulfone hollow fiber membrane module with dual intelligent response and closed-loop control according to claim 1, and its preparation method, characterized in that: The polyethersulfone hollow fiber membrane has an asymmetric sponge-like pore structure, including a support layer, and an inner surface layer and an outer surface layer covering the support layer; the average pore size of the support layer is 10 to 50 times that of the inner surface layer, the average pore size of the inner surface layer is 0.027 to 0.032 μm, the inner diameter of the hollow fiber membrane is 450 to 550 μm, and the wall thickness is 200 to 300 μm.

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