Preparation method of high-efficiency low-resistance waterproof piezoelectric filter material, and preparation and detection equipment

Abstract

The application discloses a kind of preparation method of efficient low-resistance waterproof piezoelectric filter material and preparation, detection equipment, and preparation method includes: first MoS2 is prepared MoS2 dispersion liquid by liquid phase ultrasonic peeling, then MoS2 dispersion liquid, fluorinated SiO2 Nanoparticle and polyvinyl fluoride solution are mixed, and three-phase composite spinning liquid is prepared by ultrasonic and stirring, finally, piezoelectric filter material is directly obtained by spinning, polarization treatment through electrostatic spinning mechanism.Equipment for preparation and detection is composed of electrostatic spinning mechanism, material collecting mechanism, transport mechanism, powder supply mechanism and detection mechanism, electrostatic spinning mechanism and material collecting mechanism are responsible for piezoelectric filter material forming and functionalization, transport mechanism removes piezoelectric filter material, powder supply mechanism provides dust, and detection mechanism measures the filtration efficiency, resistance, hydrophobicity and piezoelectricity of piezoelectric filter material in real time.The application can improve production efficiency, reduce cost by the synergistic design of material formula and integrated preparation, detection equipment, and can evaluate the comprehensive performance of piezoelectric filter material in real time and accurately.

Description

Technical Field

[0001] This invention relates to the field of dust control technology, specifically to a method for preparing high-efficiency, low-resistance, waterproof piezoelectric filter material and related preparation and testing equipment. Background Technology

[0002] With the increasing demands for indoor living environment quality in industries such as air filtration, dust control, precision electronics, biomedicine, and high-end manufacturing, as well as in the context of rising consumer expectations for indoor environmental quality, the efficient purification of submicron-sized particulate matter (such as PM0.3) in the air has become an urgent need. These particles are small in size and highly penetrating, posing a significant challenge to traditional filtration technologies. Traditional filter media generally suffer from an inherent contradiction between filtration efficiency and airflow resistance: increasing filter media density in pursuit of high efficiency inevitably leads to a sharp increase in system energy consumption, violating the principles of energy conservation and environmental protection.

[0003] To overcome this bottleneck, electrospun nanofiber membranes, with their high specific surface area and controllable pore structure, are considered ideal substrates for constructing next-generation high-efficiency, low-resistance filter media. However, substrate innovation is only the first step; the application of filter media in real-world, complex operating conditions faces even more severe challenges. In high-humidity environments, conventional filter media are prone to microbial growth and pore blockage due to moisture retention, leading to rapid performance degradation or even failure. Furthermore, most filter media have limited functionality, only possessing passive interception capabilities, and cannot effectively decompose captured organic pollutants, easily becoming secondary pollution sources and limiting their service life.

[0004] To address the aforementioned issues, existing technologies typically employ a "step-by-step" approach to functionalize filter media. This includes imparting hydrophobicity through post-processing or loading catalytic materials onto the surface. However, these methods suffer from inherent drawbacks such as complex processes, weak bonding between the functional layer and the matrix, and the tendency for the modified layer to detach or deactivate, making it difficult to achieve long-lasting, stable, and multifunctional synergy in the filter media. A deeper technical challenge lies in the integrated design of multifunctional materials: how to uniformly and stably composite multiple functional components, such as piezoelectric catalysis and superhydrophobicity, within a fiber matrix at the nanoscale while ensuring their activity. This is a hurdle that traditional blending processes struggle to overcome.

[0005] Furthermore, traditional filter media research and evaluation models have significant shortcomings. The preparation, functionalization, and performance testing of filter media are fragmented, requiring sample transfer between different devices. This discontinuous operation is not only inefficient but also introduces operational errors and contamination risks. It fails to establish a direct and rapid feedback loop between process parameters and final performance, severely restricting the efficiency and optimization process of new material research and development.

[0006] Therefore, the industry urgently needs a filter material technology and equipment that can address multiple requirements such as "high efficiency, low resistance, waterproofing, and piezoelectric self-cleaning" from the source of material design, and integrate controllable preparation and precise testing. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing high-efficiency, low-resistance, waterproof piezoelectric filter material, as well as preparation and testing equipment. The high-efficiency, low-resistance, waterproof piezoelectric filter material has excellent filtration efficiency, extremely low airflow resistance, long-lasting superhydrophobic properties, and piezoelectric self-cleaning ability. The preparation and testing equipment can realize the integration and automation of the entire process from material composite, spinning, online polarization to performance testing, which can improve production efficiency, reduce costs, and evaluate the comprehensive performance of piezoelectric filter material in real time and accurately.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A method for preparing a high-efficiency, low-resistance, waterproof piezoelectric filter material includes the following steps:

[0010] Step 1: Disperse bulk molybdenum disulfide (MoS2) powder in N-methylpyrrolidone solvent and stir to form a preliminary suspension. Pour the suspension into a thick-walled glass vessel and perform high-intensity liquid phase ultrasonic exfoliation treatment. Centrifuge at low speed and take the supernatant to obtain the upper MoS2 dispersion. Centrifuge the upper MoS2 dispersion at high speed to obtain a monolayer MoS2 dispersion.

[0011] Step 2: Dissolve polyvinylidene fluoride (PVDF) in N,N-dimethylformamide solvent to form a PVDF solution; under stirring conditions, add monolayer MoS2 dispersion and fluorinated silica (SiO2) nanoparticles to the PVDF solution, place the mixed solution in an ice-water bath for ultrasonic dispersion for 30 minutes, and then place the mixed solution on a magnetic stirrer and stir at room temperature for 8-12 hours to obtain a uniform three-phase composite spinning solution;

[0012] Step 3: The obtained three-phase composite spinning solution is added to the liquid supply unit of the electrospinning mechanism for spinning. During the process of the three-phase composite spinning solution jet flying towards the receiver, it passes through the strong electric field and corona discharge region generated by the sharp needle electrode array. In this process, it is solidified into spun fibers and polarization treatment is completed at the same time. The high-efficiency, low-resistance, waterproof piezoelectric filter material is directly collected on the receiver and then tested for subsequent properties such as contact angle, particulate matter concentration, resistance and piezoelectric effect.

[0013] Preferably, in step one, the liquid phase ultrasonic exfoliation is performed using an ultrasonic disruptor under ice-water bath cooling conditions, with intermittent ultrasonication for 4-8 hours; the centrifuge is a high-speed benchtop centrifuge, with a low-speed centrifugation speed of 1000-3000 rpm for 10-30 minutes; and a high-speed centrifugation speed of 8000-15000 rpm for 30-60 minutes.

[0014] Preferably, in step two, the PVDF mass concentration is 12%; the mass ratio of PVDF, monolayer MoS2 dispersion, and fluorinated SiO2 nanoparticles is 90:8:2.

[0015] Preferably, in step three, the sharp needle electrode array is connected to a negative high-voltage power supply with a voltage of -10kV to -30kV; the electrospinning parameters are set as follows: spinning voltage is 15-25 kV, receiving distance is 10-20 cm, three-phase composite spinning solution propulsion rate is 0.5-1.5 mL / h, and spinning fiber winding speed is 10-1000 rpm.

[0016] A device for preparing and testing high-efficiency, low-resistance, waterproof piezoelectric filter material includes a frame and an electrospinning mechanism, a receiving mechanism, a transport mechanism, a powder feeding mechanism, and a testing mechanism mounted on the frame; the receiving mechanism is located below the electrospinning mechanism; the transport mechanism is located between the receiving mechanism and the powder feeding mechanism; and the testing mechanism is located on the side of the powder feeding mechanism away from the receiving mechanism.

[0017] The electrospinning mechanism is used to carry the prepared three-phase composite spinning solution, which is prepared by the above preparation method. The three-phase composite spinning solution is sprayed onto the receiving mechanism in an online polarization process, and the three-phase composite spinning solution forms spinning fibers during the online polarization spraying process.

[0018] The receiving mechanism is used to receive the spun fibers and produce piezoelectric filter material;

[0019] The transport mechanism is used to transport the piezoelectric filter material to the powder feeding mechanism;

[0020] The powder feeding mechanism is used to provide aerosol dust;

[0021] The detection mechanism is used to control the operation of the electrospinning mechanism, to pump the aerosol dust to the piezoelectric filter material between the detection areas, and to detect the water resistance, piezoelectricity, airflow pressure drop during filtration, and particulate matter concentration in the airflow of the piezoelectric filter material, and to provide the detection results.

[0022] Preferably, the electrospinning mechanism includes a base, a sharp needle electrode array, a slider, a syringe, a first motor, a first screw, and a second screw; the sharp needle electrode array is fixed on the slider; a power supply is provided on the base, and the slider is slidably connected to the base; one end of the first screw is connected to the slider, and the other end is drivenly connected to the output shaft of the first motor; the syringe includes a cylinder and a push rod, one end of the push rod is equipped with a rubber head, the rubber head is slidably installed inside the cylinder, the end of the push rod away from the rubber head is fixedly connected to the second screw, and the end of the second screw away from the push rod is drivenly connected to the output shaft of the first motor; the second screw is a telescopic screw; the cylinder is opposite to the second screw and the nozzle, the annular piezoelectric ceramic sheet is connected to the ultrasonic drive power supply, and the nozzle is electrically connected to the power supply; the end of the nozzle opposite to the second screw has a spiral microgroove; the distance between the nozzle and the sharp needle electrode array is 2-3 mm, and the distance between the nozzle and the receiving mechanism is 10-20 cm.

[0023] Preferably, the receiving mechanism includes a first support column, a second support column, a roller, a cutting assembly, a metal plate, a lead screw and nut pair, and a plate base; the first support column and the second support column are slidably mounted on the frame; the roller is rotatably connected between the first support column and the second support column; a second motor is disposed inside the first support column, and the second motor is used to drive the roller to rotate; the cutting assembly is disposed between the roller and the second support column for cutting the piezoelectric filter material on the roller; the metal plate is disposed below the roller, and the plate base is slidably connected to the frame; the lead screw and nut pair is connected between the plate base and the metal plate for adjusting the distance between the plate base and the metal plate, and the lead screw and nut pair is driven by a third motor.

[0024] Preferably, the transport mechanism includes a fixed base and a multi-joint robotic arm mounted on the fixed base, the fixed base being fixedly mounted on the frame; the robotic arm has multiple rotary joints, enabling multi-degree-of-freedom movement within a plane, a sponge suction cup connected to the end flange of the multi-joint robotic arm, the sponge suction cup having a cavity extending through the thickness direction of the sponge suction cup, the cavity being connected to a vacuum line for evacuating the cavity, and a pair of ejector pins disposed inside the sponge suction cup, the ejector pins being driven by a miniature electric push rod for detaching the piezoelectric filter material from the surface of the sponge suction cup.

[0025] Preferably, the powder feeding mechanism includes an ash hopper, an aerosol dust generator, a humidifier, a baffle, a filter media clamp, a dust concentration sensor, and a humidity sensor; the ash hopper is fixed to the frame; the aerosol dust generator and the humidifier are fixed inside the ash hopper; a first opening is provided on the outer side of the ash hopper near the transport mechanism, and a baffle is provided at the first opening, the baffle being rotatably connected to the outer wall of the ash hopper; the filter media clamp is provided on the inner side of the ash hopper near the detection mechanism, and the filter media clamp is rotatably connected to the inner wall of the ash hopper via an electric hinge; the dust concentration sensor and the humidity sensor are fixed to the inner wall of the ash hopper; a first sampling point is provided on the inner side of the ash hopper, and a first sampling sensor is provided at the first sampling point; a second opening is provided on the side of the ash hopper near the detection mechanism.

[0026] Preferably, the detection mechanism includes a computer, a contact angle measuring instrument, a ventilation duct, a flow meter, a differential pressure gauge, a particle counter, and an exhaust pump; the contact angle measuring instrument, the differential pressure gauge, the particle counter, and the exhaust pump are all fixed on the frame; the contact angle measuring instrument is electrically connected to the computer; the ventilation duct is installed on the upper end of the particle counter, and the front end of the ventilation duct faces the second opening; the ventilation duct has a built-in ultrasonic transducer; the ventilation duct is connected to the exhaust pump through a flexible hose; the flow meter is installed at the connection between the ventilation duct and the flexible hose; a second sampling point is provided on the side of the ventilation duct facing the second opening, and a second sampling sensor is provided at the second sampling point; the first sampling sensor and the second sampling sensor are both electrically connected to the differential pressure gauge and the particle counter.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. In this invention, an upper layer of MoS2 dispersion is prepared by liquid-phase ultrasonic exfoliation and then combined with fluorinated SiO2 nanoparticles as a functional additive. This dispersion is then combined with PVDF-based spinning solution. This preparation method not only endows the piezoelectric filter material with piezoelectric catalytic activity through MoS2, but also fundamentally constructs the micro-nano hydrophobic structure and mechanical reinforcing phase of the piezoelectric filter material through fluorinated SiO2. The three components are combined in a specific mass ratio, which not only endows the spinning fiber with piezoelectricity and intrinsic superhydrophobicity, but also significantly enhances the mechanical properties of the fiber, making the piezoelectric filter material more robust and durable, and extending its service life.

[0029] 2. This invention innovatively designs a spiral microgroove inside the nozzle of the electrospinning mechanism and integrates a piezoelectric ceramic vibrator on the outside of the syringe. The spiral microgroove can guide the three-phase composite spinning solution to generate swirling flow, enhance the wall adhesion, and effectively prevent the three-phase composite spinning solution from dripping and the nozzle from clogging at low flow rates. The high-frequency micro-vibration generated by the piezoelectric ceramic sheet directly acts on the three-phase composite spinning solution jet, which can effectively suppress unstable flow during fiber forming and break up satellite droplets, thereby obtaining nanofibers with finer diameter and more uniform distribution, laying an excellent microstructure foundation for the preparation of high-performance piezoelectric filter materials.

[0030] 3. This invention employs an electrospinning mechanism integrated with a sharp needle electrode array and connects it to a negative high-voltage power supply. When the positively charged three-phase composite spinning liquid jet flies toward the receiving mechanism, it will be forced to pass through the strong electric field and corona discharge region generated by the array, so that the fiber completes polarization treatment at the moment of deposition and solidification. This integrates the traditional two-step process of "spinning first and then polarization" into a one-step method of "in-situ spinning-polarization", which greatly simplifies the process flow, improves production efficiency, and ensures the uniformity and depth of polarization effect.

[0031] 4. The preparation and testing equipment in this invention integrates an automated transport mechanism, a powder feeding mechanism, and a testing mechanism. The powder feeding mechanism includes an aerosol generator and a humidifier. The testing mechanism includes a particle counter, a differential pressure gauge, and a contact angle measuring instrument, which are used to measure the basic performance (filtration efficiency, resistance, and hydrophobicity) of the piezoelectric filter material online. It also integrates an ultrasonic transducer, which can apply ultrasonic excitation of a specific frequency to the piezoelectric filter material sample and simultaneously detect its piezoelectric response signal, thereby dynamically and non-destructively evaluating the activity, uniformity, and firmness of the piezoelectric layer of the piezoelectric filter material, realizing online quality inspection and life prediction of the core function (piezoelectricity) of the piezoelectric filter material.

[0032] 5. This invention overcomes the challenges of traditional filter media in balancing efficiency, resistance, environmental stability, and functional durability by improving material formulation (PVDF / MoS2 / fluorinated SiO2 three-phase composite), core processes (spiral vibration spinning and in-situ polarization), and intelligent equipment (integrated preparation and diagnosis). The piezoelectric filter media achieves a filtration efficiency of 99.5%-99.9% for PM0.3 particles, with an initial pressure drop ≤50 Pa, a contact angle ≥150°, a roll-off angle ≤10°, a piezoelectric output voltage of 0.5-2 V (under ultrasonic excitation), an organic pollutant degradation rate ≥80% (within 24 hours), and a performance degradation of <10% after ≥6 months of continuous use. It integrates high-efficiency filtration, ultra-low resistance, long-lasting hydrophobicity, and piezoelectric self-cleaning capabilities. Its preparation method is highly efficient and controllable, and its quality testing is intelligent and comprehensive, providing a high-performance, long-lasting, and precisely controllable solution for the high-end air purification field. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0034] Figure 2 This is an external schematic diagram of the present invention;

[0035] Figure 3 This is a schematic diagram of the internal structure of the present invention;

[0036] Figure 4 This is a schematic diagram of the syringe and its actuation device in this invention;

[0037] Figure 5 This is a schematic diagram of the internal structure of the nozzle in this invention;

[0038] Figure 6 This is a schematic diagram of the structure of the piezoelectric ceramic sheet at the tip of the syringe in this invention;

[0039] Figure 7 This is a schematic diagram of the material receiving mechanism in this invention;

[0040] Figure 8 This is a schematic diagram of the structure of the multi-joint robotic arm in this invention;

[0041] Figure 9 This is a schematic diagram of the ejector pin and flange in this invention;

[0042] Figure 10 This is a schematic diagram of the aerosol dust generator in this invention;

[0043] Figure 11 This is a schematic diagram of the humidifier in this invention.

[0044] in:

[0045] 1. Electrospinning mechanism; 11. Base; 12. Sharp needle electrode array; 13. Slider; 14. Injector; 131. First screw; 132. First motor; 133. Second screw; 141. Cylinder; 142. Push rod; 143. Rubber head; 144. Piezoelectric ceramic sheet; 145. Nozzle;

[0046] 2. Receiving mechanism; 21. First support column; 22. Second support column; 23. Roller; 24. Metal plate; 211. Cutting assembly; 241. Lead screw and nut pair; 242. Plate base;

[0047] 3. Transportation mechanism; 31. Fixed base; 32. Multi-joint robotic arm; 321. Sponge suction cup; 322. Flange; 323. Ejector pin;

[0048] 4. Powder feeding mechanism; 41. Ash hopper; 42. Aerosol dust generator; 43. Humidifier; 44. First sampling point; 411. Baffle; 412. Filter media clamp; 421. Dust concentration sensor; 431. Humidity sensor;

[0049] 5. Testing facility; 51. Computer; 52. Contact angle measuring instrument; 53. Ventilation duct; 54. Flow meter; 55. Differential pressure gauge; 56. Particle counter; 57. Exhaust pump; 58. Second sampling point. Detailed Implementation

[0050] The invention will now be further described with reference to the accompanying drawings.

[0051] The piezoelectric filter materials mentioned in this invention are all high-efficiency, low-resistance, waterproof piezoelectric filter materials prepared by this invention. A method for preparing a high-efficiency, low-resistance, waterproof piezoelectric filter material includes the following steps:

[0052] Step 1: Disperse bulk MoS2 powder in N-methylpyrrolidone solvent and stir to form a preliminary suspension. Pour the suspension into a thick-walled glass vessel and perform high-intensity liquid-phase ultrasonic exfoliation. Centrifuge at low speed and collect the supernatant to obtain the upper MoS2 dispersion. Centrifuge the MoS2 dispersion at high speed to obtain a monolayer MoS2 dispersion. The liquid-phase ultrasonic exfoliation is performed using an ultrasonic disruptor under ice-water bath cooling conditions with intermittent ultrasonication. The ultrasonication can be performed for 10 minutes followed by a 10-minute interval, with an interval time of 4-8 hours. A high-speed benchtop centrifuge is used. The low-speed centrifugation speed is 1000-3000 rpm for 10-30 minutes, and the high-speed centrifugation speed is 8000-15000 rpm for 30-60 minutes.

[0053] Step 2: Dissolve PVDF in N,N-dimethylformamide solvent to form a PVDF solution; under stirring conditions, add monolayer MoS2 dispersion and fluorinated silica nanoparticles to the PVDF solution, place the mixed solution in an ice-water bath for ultrasonic dispersion for 30 minutes, and then place the mixed solution on a magnetic stirrer and stir at room temperature for 8-12 hours to obtain a uniform three-phase composite spinning solution; wherein, the mass concentration of PVDF is 12%; the mass ratio of PVDF, monolayer MoS2 dispersion and fluorinated SiO2 nanoparticles is 90:8:2.

[0054] Step 3: The obtained three-phase composite spinning solution is added to the supply unit of the electrospinning mechanism for spinning. During the process of the three-phase composite spinning solution jet flying towards the collection mechanism, it passes through the strong electric field and corona discharge region generated by the sharp needle electrode array. In this process, it solidifies into fibers and simultaneously completes polarization treatment. High-efficiency, low-resistance, waterproof piezoelectric filter material is directly collected on the collection mechanism, and subsequent tests are conducted on its contact angle, particulate matter concentration, resistance, and piezoelectric effect. The sharp needle electrode array is connected to a negative high-voltage power supply with a voltage of -10kV to -30kV. The electrospinning parameters are set as follows: spinning voltage 15-25 kV, receiving distance 10-20 cm, three-phase composite spinning solution propulsion rate 0.5-1.5 mL / h, and fiber winding speed 10-1000 rpm.

[0055] Example 1

[0056] Bulk MoS2 powder was dispersed in N-methylpyrrolidone solvent and stirred to form a preliminary suspension. The suspension was then poured into a thick-walled glass dish and subjected to intermittent sonication for 4 hours under ice-water bath cooling conditions using an ultrasonic homogenizer. The mixture was then centrifuged at low speed (1000 rpm) for 10 minutes using a high-speed benchtop centrifuge, and the supernatant was collected to obtain the upper MoS2 dispersion. This upper MoS2 dispersion was then centrifuged at high speed (8000 rpm) for 30 minutes to obtain a monolayer MoS2 dispersion.

[0057] PVDF was dissolved in N,N-dimethylformamide to form a PVDF solution (mass concentration of 12%). Under stirring conditions, a monolayer MoS2 dispersion and fluorinated silica nanoparticles were added to the PVDF solution, with a mass ratio of PVDF:8:2. The mixed solution was ultrasonically dispersed in an ice-water bath for 30 minutes, and then stirred at room temperature on a magnetic stirrer for 8 hours to obtain a homogeneous three-phase composite spinning solution.

[0058] The obtained three-phase composite spinning solution was added to the supply unit of the electrospinning mechanism for spinning. During the process of the three-phase composite spinning solution jet flying towards the collection mechanism, it passed through the strong electric field and corona discharge region generated by the sharp needle electrode array. In this process, it solidified into fibers and simultaneously completed polarization treatment. High-efficiency, low-resistance, waterproof piezoelectric filter material was directly collected on the collection mechanism and then subjected to subsequent performance tests. The sharp needle electrode array was connected to a negative high-voltage power supply with a voltage of -10kV. The electrospinning parameters were set as follows: spinning voltage of 15 kV, receiving distance of 10 cm, three-phase composite spinning solution propulsion rate of 0.5 mL / h, and spinning winding speed of 100 rpm.

[0059] Example 2:

[0060] Bulk MoS2 powder was dispersed in N-methylpyrrolidone solvent and stirred to form a preliminary suspension. The suspension was then poured into a thick-walled glass dish and subjected to intermittent sonication for 8 hours under ice-water bath cooling conditions using an ultrasonic homogenizer. The mixture was then centrifuged at low speed (3000 rpm) for 30 minutes using a high-speed benchtop centrifuge, and the supernatant was collected to obtain the upper MoS2 dispersion. This upper MoS2 dispersion was then centrifuged at high speed (15000 rpm) for 60 minutes to obtain a monolayer MoS2 dispersion.

[0061] PVDF was dissolved in N,N-dimethylformamide to form a PVDF solution (mass concentration of 12%). Under stirring conditions, a monolayer MoS2 dispersion and fluorinated silica nanoparticles were added to the PVDF solution, with a mass ratio of PVDF:8:2. The mixture was ultrasonically dispersed in an ice-water bath for 30 minutes, and then stirred at room temperature on a magnetic stirrer for 12 hours to obtain a homogeneous three-phase composite spinning solution.

[0062] The obtained three-phase composite spinning solution was added to the supply unit of the electrospinning mechanism for spinning. During the process of the three-phase composite spinning solution jet flying towards the collection mechanism, it passed through the strong electric field and corona discharge region generated by the sharp needle electrode array. In this process, it solidified into fibers and simultaneously completed polarization treatment. High-efficiency, low-resistance, waterproof piezoelectric filter material was directly collected on the collection mechanism, and subsequent tests were conducted on its contact angle, particulate matter concentration, resistance, and piezoelectric effect. The sharp needle electrode array was connected to a negative high-voltage power supply with a voltage of -30kV. The electrospinning parameters were set as follows: spinning voltage of 25 kV, receiving distance of 20 cm, three-phase composite spinning solution propulsion rate of 1.5 mL / h, and spinning winding speed of 1000 rpm.

[0063] The prepared high-efficiency, low-resistance, waterproof piezoelectric filter material can achieve a filtration efficiency of 99.5%-99.9% for PM0.3 particles, with an initial pressure drop ≤50 Pa. It is superhydrophobic, with a contact angle ≥150° and a roll-off angle ≤10°. The piezoelectric output voltage is 0.5-2 V (under ultrasonic excitation), and the degradation rate of organic pollutants is ≥80% (within 24 hours). After continuous use for ≥6 months, the performance degradation is <10%. It integrates high-efficiency filtration, ultra-low resistance, long-lasting hydrophobicity, and piezoelectric self-cleaning ability.

[0064] like Figures 1 to 11 As shown, a device for preparing and testing high-efficiency, low-resistance, waterproof piezoelectric filter material includes a frame and an electrostatic spinning mechanism 1, a receiving mechanism 2, a transport mechanism 3, a powder feeding mechanism 4, and a testing mechanism 5 mounted on the frame; the receiving mechanism 2 is located below the electrostatic spinning mechanism 1; the transport mechanism 3 is located between the receiving mechanism 2 and the powder feeding mechanism 4; and the testing mechanism 5 is located on the side of the powder feeding mechanism 4 away from the receiving mechanism 2.

[0065] The electrospinning mechanism 1 is used to carry the prepared three-phase composite spinning solution and spray the three-phase composite spinning solution onto the receiving mechanism 2 in an online polarization process. The three-phase composite spinning solution forms spinning fibers during the online polarization spraying process.

[0066] The receiving mechanism 2 is used to receive the spun fibers and make them into piezoelectric filter media;

[0067] Transport mechanism 3 transports the piezoelectric filter material to powder feeding mechanism 4;

[0068] The powder feeding mechanism 4 is used to provide aerosol dust with appropriate humidity and concentration;

[0069] The testing mechanism 5 is used to control the operation of the electrospinning mechanism 1, to draw the aerosol dust inside the powder feeding mechanism 4 to the piezoelectric filter material between the testing areas, and to test the waterproof performance of the piezoelectric filter material, the airflow pressure drop during filtration, and the concentration of particulate matter in the airflow, and to provide the test results.

[0070] In this embodiment, refer to Figure 2 , Figures 4-6 The electrospinning mechanism 1 includes a base 11, a sharp needle electrode array 12, a slider 13, a syringe 14, a first motor 132, a first screw 131, and a second screw 133. A power supply is provided on the base 11. The base 11 is slidably connected to the slider 13. The side of the base 11 facing the slider 13 is provided with a groove. The slider 13 is provided with a slide rail that cooperates with the groove. A limiting groove is provided on the inner wall of the groove. The slider 13 has a limiting block that cooperates with the limiting groove. The limiting block is connected to both sides of the slide rail in the thickness direction. Through the cooperation of the limiting groove and the limiting block, the slider 13 is prevented from falling off the base 11.

[0071] The slider 13 has a screw hole that mates with the first screw 131, and the first screw 131 is installed in the screw hole; one end of the first screw 131 is connected to the output shaft of the first motor 132, and the other end is connected to the slider 13; the sharp needle electrode array 12 is fixed on the slider 13; the syringe 14 includes a cylinder 141 and a push rod 142; a rubber head 143 is installed at one end of the push rod 142, and the rubber head 143 is slidably installed inside the cylinder 141; the end of the push rod 142 away from the rubber head 143 is fixed to the second screw 133. Connections: The second screw 133 is a telescopic screw, one end of which is connected to the output shaft of the first motor 132 for transmission, and the other end is fixedly connected to the push rod 142; the front end of the cylinder 141 is provided with an annular piezoelectric ceramic plate 144 and a nozzle 145, the annular piezoelectric ceramic plate 144 is connected to the ultrasonic drive power supply, and the nozzle 145 is electrically connected to the power supply; the inner front end of the nozzle 145 has a spiral microgroove; the distance between the nozzle 145 and the sharp needle electrode array 12 is 2-3mm, and the distance between the nozzle 145 and the material collection mechanism 2 is 10-20cm. For example, the distance between the nozzle 145 and the material collection mechanism 2 can be 10cm, 13cm, 17cm, or 20cm.

[0072] After the first motor 132 starts, it drives the first screw 131 to move left and right. When the first screw 131 moves left and right, it drives the slider 13 to move left and right to achieve uniform spinning. After the first motor 132 starts, it drives the second screw 133 to extend and retract. The second screw 133 moves along the axis of the push rod 142. The push rod 142 moves linearly in the cylinder 141 and pushes the three-phase composite spinning liquid in the cylinder 141 out of the nozzle 145 through the rubber head 143. The sharp needle electrode array 12 polarizes the three-phase composite spinning liquid in the online at the moment of spraying, so that the piezoelectric filter material has a piezoelectric effect.

[0073] In this embodiment, refer to Figure 2 , Figure 7The receiving mechanism 2 includes a first support column 21, a second support column 22, a roller 23, a cutting assembly 211, a metal plate 24, a lead screw and nut pair 241, and a plate base 242. A first semi-circular groove is provided on the frame, and a first semi-circular guide rail is provided on the first support column 21 and the second support column 22. The first semi-circular guide rail slides in conjunction with the first semi-circular groove. The first semi-circular guide rail extends in the front-back direction. The first support column 21 and the second support column 22 are slidably mounted on the frame. The roller 23 is mounted between the first support column 21 and the second support column 22 via rotating shafts and bearings at both ends. A second motor is installed inside the first support column 21, and the roller 23 is driven to rotate by the second motor through a coupling. A cutting assembly 211 is installed between the roller 23 and the second support column 22. The cutting assembly 211 is used to cut the piezoelectric filter material on the roller 23. It is equipped with a telescopic blade inside, which is telescopic along the axial direction of the roller 23. After the piezoelectric filter material is formed, the telescopic blade extends along the axial direction of the roller 23 to cut the piezoelectric filter material. A metal plate 24 is installed below the roller 23. A second semi-circular guide rail is installed on the bottom surface of the plate base 242 and is slidably connected to the frame. One end of the lead screw nut pair 241 driven by the third motor is connected to the plate base 242, and the other end is connected to the metal plate 24.

[0074] The lead screw and nut assembly 241 is used to precisely adjust the height of the metal plate 24; the cutting assembly 211 cuts the piezoelectric filter material, which falls naturally onto the metal plate 24 below. The second motor drives the first support column 21, the second support column 22, and the roller 23 to slide backward, and the third motor drives the metal plate 24 to slide to the left to the contact angle measuring instrument 52 for detection.

[0075] In this embodiment, refer to Figures 8-9 The transport mechanism 3 includes a fixed base 31 and a multi-joint robotic arm 32. The fixed base 31 is fixedly mounted on a frame. The multi-joint robotic arm 32 is mounted on the fixed base 31 and has multiple rotary joints, enabling multi-degree-of-freedom movement within a plane. A square sponge suction cup 321 is connected to the end flange 322 of the multi-joint robotic arm 32. The sponge suction cup 321 is made of a porous elastic material with densely distributed micropores on its surface. The sponge suction cup 321 has a cavity penetrating its thickness direction, which is connected to a vacuum pipeline. The sponge suction cup 321 is connected to the end flange 322 of the multi-joint robotic arm 32 via a rigid mounting plate. The vacuum pipeline passes through the mounting plate and communicates with the cavity inside the sponge suction cup 321. A pair of ejector pins 323 are provided inside the sponge suction cup 321. The ejector pins 323 are driven by a miniature electric push rod 142 and are used to detach the piezoelectric filter material from the surface of the sponge suction cup 321 without damage.

[0076] In this embodiment, refer to Figure 3The powder feeding mechanism 4 includes an ash hopper 41, an aerosol dust generator 42, a humidifier 43, a baffle 411, a filter media clamp 412, a dust concentration sensor 421, and a humidity sensor 431. The ash hopper 41 is fixed on the frame. The aerosol dust generator 42 and the humidifier 43 are fixed inside the ash hopper 41. A first opening is provided on the outer side of the ash hopper 41 near the transport mechanism 3, and a baffle 411 is provided at the first opening. The baffle 411 is rotatably connected to the outer wall of the ash hopper 41. A filter media clamp 412 is provided on the inner side of the ash hopper 41 near the detection mechanism 5. The filter media clamp 412 is rotatably connected to the inner wall of the ash hopper 41 via an electric hinge. The dust concentration sensor 421 and the humidity sensor 431 are fixed to the inner wall of the ash hopper 41. A first sampling point 44 is provided on the inner side of the ash hopper 41, and a first sampling sensor is provided at the first sampling point 44. A second opening is provided on the side of the ash hopper 41 near the detection mechanism 5.

[0077] In this embodiment, refer to Figure 3 The testing unit 5 includes a computer 51, a contact angle measuring instrument 52, a ventilation duct 53, a flow meter 54, a differential pressure gauge 55, a particle counter 56, and an exhaust pump 57. The contact angle measuring instrument 52, differential pressure gauge 55, particle counter 56, and exhaust pump 57 are fixed on a frame. The contact angle measuring instrument 52 is electrically connected to the computer 51. The ventilation duct 53 is installed on the upper end of the particle counter 56, with its front end facing the second opening. The ventilation duct 53 has a built-in ultrasonic transducer. The ventilation duct 53 is connected to the exhaust pump 57 via a flexible hose. A flow meter 54 is installed at the connection between the ventilation duct 53 and the flexible hose. A second sampling point 58 is set on the side of the ventilation duct 53 facing the second opening, and a second sampling sensor is set at the second sampling point 58. Both the first and second sampling sensors are electrically connected to the differential pressure gauge 55 and the particle counter 56. The computer 51 is used to control electrospinning and observe the test results of the piezoelectric filter material.

[0078] By measuring the pressure drop during filtration of the piezoelectric filter media at the first sampling point 44 and the second sampling point 58, the concentration of particulate matter in the air before and after filtration, and measuring the piezoelectric effect of the high-efficiency, low-resistance, and waterproof piezoelectric filter media, the filtration efficiency of different particle sizes is calculated, a pressure drop curve of the piezoelectric filter media is provided, the relationship between pressure drop and inlet air velocity and piezoelectric performance are shown, and the performance of the piezoelectric filter media under different working conditions is evaluated.

[0079] Working principle

[0080] The equipment for preparing and testing this high-efficiency, low-resistance, waterproof piezoelectric filter material consists of several parts, including an electrospinning mechanism 1, a material receiving mechanism 2, a conveying mechanism 3, a powder feeding mechanism 4, and a testing mechanism 5. Its working principle can be divided into the following main steps:

[0081] Electrospinning polarization process

[0082] After the equipment is started, the electrospinning mechanism 1 is responsible for spraying the prepared three-phase composite spinning solution onto the receiving mechanism 2 through the nozzle 145. During the spraying process, online polarization is achieved through the sharp needle electrode array 12. The electrospinning mechanism 1 generates a high voltage through the power supply, driving the nozzle 145 to release the three-phase composite spinning solution and forming an electrostatic field between the nozzle 145 and the receiving mechanism 2, and between the nozzle 145 and the sharp needle electrode array 12. Under the action of the electric field, the three-phase composite spinning solution is online polarized, stretched, and forms spun fibers. To ensure the uniformity of the three-phase composite spinning solution, the electrospinning mechanism 1 drives the second screw 133 to rotate through the first motor 132. When the second screw 133 rotates, it pushes the push rod 142 to move, thereby promoting the directional output of the three-phase composite spinning solution. At the same time, the design of the spiral microgroove and the mechanical oscillation of the piezoelectric ceramic sheet 144 are used to prevent the sedimentation of particles in the three-phase composite spinning solution, thus ensuring the uniformity of the three-phase composite spinning solution.

[0083] piezoelectric filter media collection

[0084] The receiving mechanism 2 is responsible for receiving the spun fibers. The roller 23 in the receiving mechanism 2 receives the piezoelectric filter material, which adheres to the roller 23. The cutting assembly 211 moves laterally to cut the piezoelectric filter material from above, and the material falls naturally onto the metal plate 24 below. The metal plate 24 slides to the left to the contact angle measuring instrument 52, which monitors the waterproof performance of the piezoelectric filter material in real time.

[0085] Piezoelectric filter media transportation

[0086] The polarized piezoelectric filter media undergoes further processing via transport mechanism 3. Transport mechanism 3 uses a sponge suction cup 321 to vacuum-adsorb the piezoelectric filter media located on the metal plate 24, passing it through the baffle 411 on the outer wall of the ash hopper 41 and the first opening, transporting the piezoelectric filter media to the filter media clamp 412 at the second opening of the ash hopper 41. At this point, a hinge rotates the filter media clamp 412, closing the vacuum adsorption effect of the sponge suction cup 321. A pin 323 provides a small, controllable, mechanical pry that breaks the microscopic adhesion between the piezoelectric filter media and the sponge suction cup 321, allowing air to re-enter the contact surface. The piezoelectric filter media falls naturally, and the filter media clamp 412 rotates again to adhere to the inner wall of the ash hopper 41. The piezoelectric filter media is then clamped in the filter media clamp 412 for subsequent testing.

[0087] Dust supply and filtration

[0088] The powder feeding mechanism 4 is responsible for providing aerosol dust of appropriate concentration and humidity to simulate the filtration effect in an actual working environment. The aerosol dust generator 42 releases dust particles into the ash hopper 41, the humidifier 43 adjusts the humidity, the dust concentration sensor 421 detects the dust concentration in the ash hopper 41 in real time, and the humidity sensor 431 detects the dust humidity in the ash hopper 41 in real time. The airflow diffuses the dust particles to ensure uniform distribution. Subsequently, the dust enters the filtration area with the airflow and comes into contact with the piezoelectric filter media. The piezoelectric filter media then exerts its high-efficiency, low-resistance filtration performance, capturing particulate matter in the airflow.

[0089] Testing and performance evaluation

[0090] Testing unit 5 tests the initial filter media and the airflow after filtration through the piezoelectric filter media. Testing unit 5 uses a contact angle measuring instrument 52 to test the water resistance of the piezoelectric filter media. A flow meter 54 and first and second sensors monitor the airflow pressure drop, particulate matter concentration before and after filtration, and piezoelectricity during the filtration process. Computer 51 controls the operating status of each component, collects data, and calculates filtration efficiency and piezoelectricity. By measuring the filtration effect on particles of different sizes and plotting pressure drop curves, the performance of the piezoelectric filter media under different operating conditions is tested.

[0091] Results Feedback and Adjustments

[0092] Ultimately, computer 51 provides real-time feedback and adjusts equipment parameters, such as electrospinning voltage and spinneret flow rate, based on the detection data to optimize the quality and filtration efficiency of the piezoelectric filter media. The equipment automatically adjusts the operating status of the electrospinning mechanism 1, the powder feeding mechanism 4, and other components according to the detection results to ensure the system operates in optimal condition.

[0093] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the scope of protection of the present invention.

Claims

1. A method for preparing a high-efficiency, low-resistance, waterproof piezoelectric filter material, characterized in that, Includes the following steps: Step 1: Disperse bulk MoS2 powder in N-methylpyrrolidone solvent and stir to form a preliminary suspension. Pour into a thick-walled glass vessel and perform high-intensity liquid phase ultrasonic exfoliation treatment. Centrifuge at low speed and take the supernatant to obtain the upper MoS2 dispersion. Centrifuge the upper MoS2 dispersion at high speed to obtain a monolayer MoS2 dispersion. Step 2: Dissolve PVDF in N,N-dimethylformamide solvent to form PVDF solution; under stirring conditions, add monolayer MoS2 dispersion and fluorinated SiO2 nanoparticles to PVDF solution, place the mixed solution in an ice-water bath for ultrasonic dispersion for 30 minutes, and then place the mixed solution on a magnetic stirrer for room temperature stirring for 8-12 hours to obtain a uniform three-phase composite spinning solution; Step 3: The obtained three-phase composite spinning solution is added to the liquid supply unit of the electrospinning mechanism for spinning. During the process of the three-phase composite spinning solution jet flying towards the receiver, it passes through the strong electric field and corona discharge region generated by the sharp needle electrode array. In this process, it is solidified into spun fibers and polarization treatment is completed at the same time. The high-efficiency, low-resistance, waterproof piezoelectric filter material is directly collected on the receiver and then tested for subsequent properties such as contact angle, particulate matter concentration, resistance and piezoelectric effect.

2. The method for preparing a high-efficiency, low-resistance, waterproof piezoelectric filter material as described in claim 1, characterized in that, In step one, the liquid phase ultrasonic exfoliation is performed using an ultrasonic disruptor under ice-water bath cooling conditions, with intermittent ultrasonication for 4-8 hours; a high-speed benchtop centrifuge is selected, with a low-speed centrifugation speed of 1000-3000 rpm for 10-30 minutes; and a high-speed centrifugation speed of 8000-15000 rpm for 30-60 minutes.

3. The method for preparing a high-efficiency, low-resistance, waterproof piezoelectric filter material as described in claim 1, characterized in that, In step two, the PVDF mass concentration is 12%; the mass ratio of PVDF, monolayer MoS2 dispersion, and fluorinated SiO2 nanoparticles is 90:8:

2.

4. The method for preparing a high-efficiency, low-resistance, waterproof piezoelectric filter material as described in claim 1, characterized in that, In step three, the sharp needle electrode array is connected to a negative high-voltage power supply with a voltage of -10kV to -30kV. The electrospinning parameters are set as follows: spinning voltage is 15-25 kV, receiving distance is 10-20 cm, three-phase composite spinning solution propulsion rate is 0.5-1.5 mL / h, and spinning fiber winding speed is 10-1000 rpm.

5. A device for preparing and testing high-efficiency, low-resistance, waterproof piezoelectric filter media, characterized in that, The device includes a frame and an electrospinning mechanism (1), a receiving mechanism (2), a transport mechanism (3), a powder feeding mechanism (4), and a detection mechanism (5) mounted on the frame. The receiving mechanism (2) is located below the electrospinning mechanism (1). The transport mechanism (3) is located between the receiving mechanism (2) and the powder feeding mechanism (4). The detection mechanism (5) is located on the side of the powder feeding mechanism (4) away from the receiving mechanism (2). The electrospinning mechanism (1) is used to carry the prepared three-phase composite spinning solution, which is prepared by the preparation method of any one of claims 1-4. The three-phase composite spinning solution is sprayed onto the receiving mechanism (2) in an online polarization process, and the three-phase composite spinning solution forms spinning fibers during the online polarization spraying process. The receiving mechanism (2) is used to receive the spun fibers and make piezoelectric filter material; The transport mechanism (3) is used to transport the piezoelectric filter material to the powder feeding mechanism (4); The powder feeding mechanism (4) is used to provide aerosol dust; The detection mechanism (5) is used to control the operation of the electrospinning mechanism (1), to pump the aerosol dust to the piezoelectric filter material between the detection areas, and to detect the waterproofness, piezoelectricity, airflow pressure drop during filtration and particulate matter concentration in the airflow of the piezoelectric filter material, and to give the detection results.

6. The equipment for preparing and testing high-efficiency, low-resistance, waterproof piezoelectric filter material as described in claim 5, characterized in that, The electrospinning mechanism (1) includes a base (11), a sharp needle electrode array (12), a slider (13), a syringe (14), a first motor (132), a first screw (131), and a second screw (133); the sharp needle electrode array (12) is fixed on the slider (13); a power supply is provided on the base (11), and the slider (13) is slidably connected to the base (11); one end of the first screw (131) is connected to the slider (13), and the other end is drivenly connected to the output shaft of the first motor (132); the syringe (14) includes a cylinder (141) and a push rod (142), one end of the push rod (142) is equipped with a rubber head (143), the rubber head (143) is slidably installed inside the cylinder (141), and the push rod (142) is slidably installed inside the cylinder (141). 2) The end away from the rubber head (143) is fixedly connected to the second screw (133), and the end of the second screw (133) away from the push rod (142) is connected to the output shaft of the first motor (132) via transmission; the second screw (133) is a telescopic screw; the end of the cylinder (141) away from the second screw (133) is provided with an annular piezoelectric ceramic sheet (144) and a nozzle (145), the annular piezoelectric ceramic sheet (144) is connected to the ultrasonic drive power supply, and the nozzle (145) is electrically connected to the power supply; the end of the nozzle (145) away from the second screw (133) is a spiral microgroove; the distance between the nozzle (145) and the sharp needle electrode array (12) is 2-3mm, and the distance between the nozzle (145) and the receiving mechanism (2) is 10-20cm.

7. The equipment for preparing and testing high-efficiency, low-resistance, waterproof piezoelectric filter material as described in claim 5, characterized in that, The receiving mechanism (2) includes a first support column (21), a second support column (22), a roller (23), a cutting assembly (211), a metal plate (24), a lead screw and nut pair (241), and a plate base (242); the first support column (21) and the second support column (22) are slidably mounted on the frame; the roller (23) is rotatably connected between the first support column (21) and the second support column (22); a second motor is provided inside the first support column (21), and the second motor is used to drive the roller (23) to rotate; The cutting assembly (211) is disposed between the roller (23) and the second support column (22) for cutting the piezoelectric filter material on the roller (23); the metal plate (24) is disposed below the roller (23), and the plate base (242) is slidably connected to the frame; the lead screw nut pair (241) is connected between the plate base (242) and the metal plate (24) for adjusting the distance between the plate base (242) and the metal plate (24), and the lead screw nut pair (241) is driven by a third motor.

8. The equipment for preparing and testing high-efficiency, low-resistance, waterproof piezoelectric filter material as described in claim 5, characterized in that, The transport mechanism (3) includes a fixed base (31) and a multi-joint robotic arm (32) mounted on the fixed base (31). The fixed base (31) is fixedly mounted on the frame. The robotic arm has multiple rotary joints and can move in multiple degrees of freedom in a plane. A sponge suction cup (321) is connected to the end flange (322) of the multi-joint robotic arm (32). The sponge suction cup (321) has a cavity that extends through the thickness direction of the sponge suction cup (321). The cavity is connected to a vacuum pipeline to evacuate the cavity. A pair of ejector pins (323) are provided inside the sponge suction cup (321). The ejector pins (323) are driven by a miniature electric push rod (142) to detach the piezoelectric filter material from the surface of the sponge suction cup (321).

9. The equipment for preparing and testing high-efficiency, low-resistance, waterproof piezoelectric filter material as described in claim 5, characterized in that, The powder feeding mechanism (4) includes an ash hopper (41), an aerosol dust generator (42), a humidifier (43), a baffle (411), a filter media clamp (412), a dust concentration sensor (421), and a humidity sensor (431). The ash hopper (41) is fixed on the frame. The aerosol dust generator (42) and the humidifier (43) are fixed inside the ash hopper (41). A first opening is provided on the outer side of the ash hopper (41) near the transport mechanism (3), and a baffle (411) is provided at the first opening. The baffle (411) and the ash hopper are connected. (41) Rotatable connection of the outer wall; the filter material clamp (412) is provided on the inner side of the ash hopper (41) near the detection mechanism (5), and the filter material clamp (412) is rotatably connected to the inner wall of the ash hopper (41) by an electric hinge; the dust concentration sensor (421) and the humidity sensor (431) are fixed on the inner wall of the ash hopper (41); a first sampling point (44) is provided on the inner side of the ash hopper (41), and a first sampling sensor is provided at the first sampling point (44); a second opening is provided on the side of the ash hopper (41) near the detection mechanism (5).

10. The equipment for preparing and testing high-efficiency, low-resistance, waterproof piezoelectric filter material as described in claim 9, characterized in that, The detection mechanism (5) includes a computer (51), a contact angle measuring instrument (52), a ventilation duct (53), a flow meter (54), a differential pressure gauge (55), a particle counter (56), and an exhaust pump (57); the contact angle measuring instrument (52), the differential pressure gauge (55), the particle counter (56), and the exhaust pump (57) are all fixed on the frame; the contact angle measuring instrument (52) is electrically connected to the computer (51); the ventilation duct (53) is installed on the upper end of the particle counter (56), and the front end of the ventilation duct (53) The ventilation duct (53) is oriented towards the second opening; an ultrasonic transducer is built into the ventilation duct (53); the ventilation duct (53) is connected to the exhaust pump (57) via a flexible hose; a flow meter (54) is installed at the connection between the ventilation duct (53) and the flexible hose; a second sampling point (58) is provided on the side of the ventilation duct (53) facing the second opening, and a second sampling sensor is provided at the second sampling point (58); the first sampling sensor and the second sampling sensor are both electrically connected to the differential pressure gauge (55) and the particle counter (56).

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