Preparation and application of zwitterionic porphyrin-based conjugated microporous polymer composite fiber membrane

Abstract

The application relates to preparation and application of a zwitterion-containing porphyrin-based conjugated microporous polymer composite fiber membrane, and components of the composite fiber material include: a porphyrin-based conjugated microporous polymer, a zwitterionic polyionic liquid and a polymer matrix; wherein the polymer matrix fiber is doped with the porphyrin-based conjugated microporous polymer and the zwitterionic polyionic liquid. The zwitterion-containing porphyrin-based conjugated microporous polymer composite fiber membrane has the advantages of salt resistance, fast evaporation rate and high photo-thermal conversion efficiency, and has potential application value in seawater desalination, wastewater purification, sterilization and the like.

Description

Technical Field

[0001] This invention belongs to the field of functional fiber materials, and specifically relates to the preparation and application of a zwitterionic porphyrin-based conjugated microporous polymer composite fiber membrane. Background Technology

[0002] Photothermal conversion technology utilizes photothermal materials to absorb solar energy and convert it into thermal energy through energy conversion mechanisms such as relaxation effect, local plasmon resonance effect, and energy level transition. This thermal energy can be used for seawater evaporation and freshwater collection. Conjugated microporous polymers are porous organic polymers with a π-conjugated framework structure, high specific surface area, and high porosity. They have excellent absorption capacity for visible light, and their structural design is flexible and controllable. Photothermal materials with excellent light absorption performance and photothermal conversion capabilities are a class of green and environmentally friendly materials with significant research and development value.

[0003] Porphyrins are a class of highly conjugated aromatic compounds with multidentate coordination, exhibiting excellent electron transfer capabilities and light absorption. Under light irradiation, they can generate singlet oxygen for sterilization and possess good chemical stability. When used for seawater desalination through photothermal conversion, they need to be mounted on a suitable substrate to form an evaporation device. However, traditional evaporators create a salt concentration gradient between the upper and lower regions during evaporation, promoting salt crystallization and accumulation on the surface of the evaporation material, blocking water transport channels, affecting the material's absorption of solar energy, and consequently impacting the photothermal evaporation efficiency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing and applying a zwitterionic porphyrin-based conjugated microporous polymer composite fiber membrane.

[0005] This invention provides a composite fiber material, the composite fiber material comprising: porphyrin-based conjugated microporous polymer, amphoteric polyionic liquid, and polymer matrix; wherein the polymer matrix fiber is doped with porphyrin-based conjugated microporous polymer and amphoteric polyionic liquid.

[0006] Preferably, the porphyrin-based conjugated microporous polymer has the following structural formula:

[0007] The wavy lines represent repeating units; the amphoteric polyionic liquid is (sodium poly3-(1-vinyl-3-imidazolium)propanesulfonate), with the structural formula [structure missing]. Where n is 5000 or more, and further, n = 5000-20000; the polymer matrix is ​​polyacrylonitrile (PAN) with a molecular weight of 100000-180000.

[0008] This invention provides a method for preparing a composite fiber material, comprising:

[0009] A porphyrin-based conjugated microporous monomer, an amphoteric polyionic liquid, a polymer matrix material, and a solvent are mixed to obtain a spinning solution. After electrospinning, a fiber membrane is obtained. The fiber membrane is then immersed in an oxidant solution to obtain a composite fiber material.

[0010] Preferably, the porphyrin-based conjugated microporous monomer is carbazole-based porphyrin; and the amphoteric polyionic liquid is (sodium poly-3-(1-vinyl-3-imidazolium)propanesulfonate).

[0011] The method for preparing the porphyrin-based conjugated microporous monomer includes: mixing acetic acid, nitrobenzene, and 3,5-bis(9H-carbazole-9-yl)benzaldehyde and heating to 100-120℃, then adding pyrrole and stirring the reaction for 0.5-2 hours, followed by purification to obtain the porphyrin-based conjugated microporous monomer; wherein the molar ratio of 3,5-bis(9H-carbazole-9-yl)benzaldehyde to pyrrole is 1:1-2.

[0012] The preparation method of the amphoteric polyionic liquid includes: mixing 1-vinylimidazolium, sodium 3-bromopropanesulfonate, 2,6-bis(tert-butyl)-p-cresol, and a solvent, reacting at 65-70°C for 12-24 h, purifying to obtain sodium 3-(1-vinyl-3-imidazolium)propanesulfonate; mixing sodium 3-(1-vinyl-3-imidazolium)propanesulfonate, water, and an initiator (such as VA-086), treating in a liquid nitrogen bath, reacting at 70-75°C for 12-24 h, dialyzing, adding to lithium bis(trifluoromethanesulfonyl)imide, stirring overnight, and drying to obtain poly(1-vinyl-3-imidazolium)propanesulfonate.

[0013] In the preparation method of the amphoteric polyionic liquid, the ratio of 1-vinylimidazolium, sodium 3-bromopropanesulfonate, 2,6-bis(tert-butyl)-p-cresol, and solvent is 50-55 mmol: 50-60 mmol: 5-15 mg: 5-20 ml; wherein the solvent includes DMF; and the molar ratio of sodium 3-(1-vinyl-3-imidazolium)propanesulfonate, initiator VA-086, and lithium bis(trifluoromethanesulfonyl)imide is 20-25:0.1-0.5:20-30.

[0014] Preferably, the polymer matrix material comprises polyacrylonitrile (molecular weight 100,000 to 180,000); the solvent comprises N,N-dimethylformamide.

[0015] Preferably, the molecular weight Mw of the polymer matrix material is 100,000 to 180,000.

[0016] Preferably, the mass ratio of the porphyrin-based conjugated microporous monomer to the amphoteric polyionic liquid is (1-2):1; and the mass ratio of the total amount of the porphyrin-based conjugated microporous monomer and the amphoteric polyionic liquid to the polymer matrix material is (1-6):1.

[0017] The mixture is obtained by stirring at room temperature for 6-10 hours to obtain the spinning solution.

[0018] Preferably, the oxidant solution is a methanol solution containing ferric chloride; wherein the ratio of ferric oxide to methanol is 150-200 mg: 2-10 mL.

[0019] Preferably, the soaking time in the oxidant solution is 8-12 hours.

[0020] Preferably, the electrospinning process parameters include: temperature 20-30℃, humidity 40-50%, operating voltage 8-14kV, and receiver rate 1mLh. -1 The rotational speed is 400–700 rpm;

[0021] Preferably, the composite fibers undergo post-treatment after washing.

[0022] Preferably, the washing is performed using an organic solvent and / or water until the filtrate is colorless and transparent; wherein the organic solvent is methanol.

[0023] Preferably, the post-treatment is vacuum drying and / or hot pressing.

[0024] Furthermore, the vacuum drying is performed at 50–100°C for 8–15 hours; the hot pressing treatment is performed at 80–100°C and 2–3 MPa for 2–6 minutes.

[0025] This invention provides an application of any of the composite fiber materials described above in the fields of seawater desalination, wastewater purification, and sterilization, such as its use as an antibacterial photothermal evaporator for seawater and organic solvents.

[0026] The composite membrane in this invention comprises a porphyrin-based conjugated microporous polymer, an amphoteric polyionic liquid, and polyacrylonitrile. The preparation method includes: blending a porphyrin-based conjugated microporous monomer, an amphoteric polyionic liquid, and a polymer matrix, followed by electrospinning to obtain a fiber membrane; then immersing the fiber membrane in a ferric chloride solution for oxidative polymerization to obtain a photothermal fiber membrane doped with a porphyrin-based conjugated microporous polymer and an amphoteric polyionic liquid, with the polymer matrix as the substrate.

[0027] This invention provides a zwitterionic porphyrin-based conjugated microporous polymer composite fiber membrane. By introducing a zwitterionic polyionic liquid, the anions and cations of the liquid generate charge interactions with sodium and chloride ions respectively, breaking the original salt concentration gradient caused by evaporation and thus preventing salt crystallization. Simultaneously, the fiber membrane has numerous pores, allowing for rapid water transport and further promoting changes in the salt concentration gradient, overcoming the salt accumulation problem of traditional evaporators.

[0028] This invention involves embedding a zwitterionic porphyrin-based conjugated microporous polymer composite fiber membrane within polystyrene foam, which is then placed in a culture medium containing seawater, organic dye, and bacteria for photothermal evaporation. Indoor testing utilizes a solar simulator for irradiation. The seawater (R) is typically from the East China Sea, and the organic dyes are methylene blue and rhodamine aqueous solutions. The bacterial culture medium used is methicillin-resistant Staphylococcus aureus (MRSA) culture.

[0029] This invention assembles a carbazole porphyrin conjugated microporous polymer (PCP) as a photothermal material within a fiber membrane with a unique pore structure, and then introduces PIL (polyurethane infusion polymer). The interaction of ionic groups attracts sodium and chloride ions from the solution, overcoming the salt accumulation problem encountered in conventional evaporators during photothermal evaporation. Simultaneously, the porous structure of the fiber membrane promotes water transport. The clean water produced by the evaporator meets World Health Organization (WHO) standards. Furthermore, the singlet oxygen generated by the carbazole porphyrin structure of the photothermal material under light irradiation can effectively kill bacteria present in seawater. The evaporator exhibits good salt stability and photothermal conversion efficiency.

[0030] Beneficial effects

[0031] This invention prepares carbazole porphyrin conjugated microporous monomers via the Adler reaction, and then blends them with amphoteric polyionic liquids to prepare amphoteric fiber-structured photothermal evaporation membranes, thereby achieving high-efficiency photothermal evaporation performance as well as salt resistance and antibacterial properties.

[0032] The preparation process of this invention is simple, the equipment is mature, and it can be mass-produced.

[0033] This invention has excellent application performance and has good application prospects in the fields of seawater and wastewater purification and sterilization.

[0034] The preparation method of this invention has the advantages of simple operation and large-scale production; the zwitterionic porphyrin-based conjugated microporous polymer composite fiber membrane has the advantages of salt resistance, fast evaporation rate and high photothermal conversion efficiency, and has potential application value in seawater desalination, wastewater purification and sterilization. Attached Figure Description

[0035] Figure 1 The images are scanning electron microscope (SEM) images of the polymer obtained in Example 1; where (a) scale bar is 2 μm and (b) scale bar is 500 nm.

[0036] Figure 2 The Fourier transform infrared spectrum of the polymer obtained in Example 1;

[0037] Figure 3 The N2 adsorption-desorption curve of the polymer obtained in Example 1;

[0038] Figure 4This is a theoretical pore size distribution diagram of the nonlocal density function of the polymer obtained in Example 1;

[0039] Figure 5 The polymer obtained in Example 1 at 1 kW m -2 Surface temperature-time curve under simulated sunlight irradiation;

[0040] Figure 6 The 1H NMR spectrum of the amphoteric polyionic liquid obtained in Example 2;

[0041] Figure 7 This is a scanning electron microscope image of the fiber membrane obtained in Example 3;

[0042] Figure 8 The fiber membrane obtained in Example 3 at 1 kW m -2 Surface temperature-time curve under simulated sunlight irradiation;

[0043] Figure 9 Thermogravimetric analysis diagram of the fiber membrane obtained in Example 3;

[0044] Figure 10 The fiber obtained in Example 4 at 1 kW m -2 Surface temperature-time curves during evaporation under simulated sunlight irradiation;

[0045] Figure 11 The evaporation rate of the fiber membrane obtained in Example 4;

[0046] Figure 12 This is a graph showing the changes in the concentration of metal ions in seawater before and after desalination via a fiber membrane in Example 5.

[0047] Figure 13 This is a comparison diagram of the different fiber membranes undergoing evaporation cycles in Example 6;

[0048] Figure 14 The UV-Vis absorbance curves of the dye wastewater and its evaporated water before and after purification by the fiber membrane in Example 7 are shown.

[0049] Figure 15 This is a comparison chart of the bactericidal performance of the fiber membrane in Example 8;

[0050] Figure 16 The structural formula for a porphyrin-based conjugated microporous polymer;

[0051] Figure 17 The structural formula is that of sodium poly(1-vinyl-3-imidazolium)propanesulfonate.

[0052] Figure caption: PAN-M is a polyacrylonitrile fiber membrane obtained by electrospinning polyacrylonitrile; PCP@PAN-M is a precursor membrane obtained by electrospinning polyacrylonitrile and carbazole-based porphyrin monomers, which is then oxidatively polymerized to obtain a polyacrylonitrile / carbazole-based porphyrin conjugated microporous polymer membrane; PCP / PIL@PAN-M is a precursor membrane obtained by electrospinning polyacrylonitrile, carbazole-based porphyrin monomers, and sodium poly(1-vinyl-3-imidazolium)propanesulfonate, which is then oxidatively polymerized to obtain a polyacrylonitrile / carbazole-based porphyrin conjugated microporous polymer / sodium poly(1-vinyl-3-imidazolium)propanesulfonate membrane. Detailed Implementation

[0053] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0054] Raw material sources: Pyrrole (>99.0%) was purchased from Shanghai Chemical Industry Development Co., Ltd.; 3,5-bis(9H-carbazole-9-yl)benzaldehyde (99%) was purchased from Gino (Suzhou) New Materials Co., Ltd.; Acetic acid (analytical grade), nitrobenzene (chemically pure), N,N-dimethylformamide (DMF, chemically pure), ferric chloride (chemically pure), and nitromethane (chemically pure) were purchased from Sinopharm Chemical Reagent Co., Ltd.; Chloroform (analytical grade), polyacrylonitrile (99%, Mw=150,000), and methanol (analytical grade) were purchased from Shanghai Titan Technology Co., Ltd.

[0055] Example 1

[0056] Preparation of carbazole-based porphyrin conjugated microporous polymers as photothermal conversion materials.

[0057] Acetic acid (13 mL), nitrobenzene (9 mL), and 3,5-bis(9H-carbazole-9-yl)benzaldehyde (700 mg, 1.6 mmol) were mixed and heated to 120 °C. Pyrrole (112 μL, 1.6 mmol) was slowly added dropwise while the mixture was stirred continuously for 1 h. The reaction mixture was then cooled to ambient temperature. The solution was filtered, the crude powder sample was washed with methanol, and dried under vacuum to obtain CP (carbazole-porphyrin) monomer. CP was soaked in a solution containing an oxidant (283.85 mg ferric chloride and 4 mL methanol) for 12 h. The resulting crude product was washed with methanol and chloroform until the filtrate was colorless and transparent, and then dried under vacuum at 60 °C for 12 h. This product was designated as carbazole-porphyrin conjugated microporous polymer PCP, with the following structural formula: Figure 16 As shown.

[0058] The microstructure of the PCP (carbazole porphyrin conjugated microporous polymer) obtained in this example under a scanning electron microscope is as follows: Figure 1 As shown, the polymer exhibits aggregated nanosphere-like particles.

[0059] The Fourier transform infrared spectrum of the polymer obtained in this example is as follows: Figure 2 As shown, the aldehyde reactant is at 1700 cm⁻¹ -1 The characteristic peak value (C=O tensile vibration) at 920cm and -1 (CH bending vibration) disappears in PCP. Furthermore, PCP at 800 cm⁻¹... -1 The peaks at 2300-2400 cm⁻¹ show the CH bending vibration of the porphyrin ring. -1 The NH vibration peak at [location missing]. All of the above characteristics verify the successful synthesis of the carbazole-based porphyrin conjugated microporous polymer.

[0060] The N2 adsorption-desorption curve of the polymer obtained in this example is as follows: Figure 3 As shown, the specific surface area of ​​PCP calculated using the Brunauer-Emmett-Teller (BET) model is 828 m². 2 g -1 This shows that the polymer has a large specific surface area. The pore size distribution diagram based on the non-local density function theory is shown below. Figure 4 The conjugated microporous polymer shown has a hierarchical distribution of pores (micropores, mesopores), especially clustered around 2 nm, indicating that most of the polymer is a microporous structure.

[0061] The polymer obtained in this embodiment is at 1 kW m -2 The surface temperature of the polymer changes as follows after 30 minutes of simulated sunlight exposure: Figure 5 As shown, the polymer exhibits a rapid thermal response, with a maximum surface temperature reaching 83°C within 30 minutes. The polymer also demonstrates excellent light absorption and photothermal conversion properties.

[0062] Example 2

[0063] Preparation of amphoteric polyionic liquids with salt-resistant hydrophilic structures:

[0064] 1-Vinylimidazole (5 g, 53.1 mmol, 1 eq), sodium 3-bromopropanesulfonate (12.55 g, 55.7 mmol, 1.05 eq), 10 mg of 2,6-bis(tert-butyl)-p-cresol, and 10 mL of LDM were added to a 100 mL single-necked round-bottom flask, and the mixture was reacted at 70 °C for 24 h. After the reaction was complete, the reaction solution was placed at room temperature and added to 200 mL of ice-cold ether, and then stirred overnight. The precipitate was collected by filtration, washed with ether, and dried. The product (5 g, 23.12 mmol, 1 eq) and 10 mL of water were then added to a 100 mL double-necked flask, and VA-086 (0.05 g, 0.17 mmol, 0.007 eq) was added as an initiator. The mixture was then subjected to freeze-thaw cycles in liquid nitrogen for 20 min per cycle, for a total of 3 cycles to remove oxygen from the system, and then reacted at 75 °C for 24 h. At the end of the reaction, the solution was dialyzed in deionized water for 3 days using a dialysis bag with an MWCO of 3500 to remove unreacted monomers. The dialysate was then concentrated under vacuum. Lithium bis(trifluoromethanesulfonyl)imide (7.96 g, 27.74 mmol, 1.2 eq) was then added and stirred overnight. The mixture was filtered and dried under vacuum at 60 °C to obtain sodium poly(1-vinyl-3-imidazolium)propanesulfonate (PIL, structural formula as shown). Figure 17 (As shown).

[0065] The 1H NMR spectrum of the amphoteric polyionic liquid obtained in this example is as follows: Figure 6 The results show that the ¹H NMR (400MHz, Deuterium Oxide) values ​​are δ 9.02 (t, J = 1.7Hz, ¹H), 7.73 (t, J = 2.0Hz, ¹H), 7.56 (t, J = 1.9Hz, ¹H), 7.08 (dd, J = 15.6, 8.7Hz, ¹H), 5.74 (dd, J = 15.6, 2.8Hz, ¹H), 5.36 (dd, J = 8.7, 2.8Hz, ¹H), 4.35 (t, J = 7.2Hz, 2H), 2.88 (dd, J = 8.2, 6.6Hz, 2H), and 2.28 (p, J = 7.3Hz, 2H), indicating the successful synthesis of the amphoteric polyionic liquid.

[0066] Example 3

[0067] Preparation of a zwitterionic fiber-structured photothermal composite film as an evaporation device:

[0068] 0.5 g of PAN (Mw = 100,000–180,000) was dissolved in 4.8 g of DMF and stirred for 10 h to form a uniformly dispersed PAN electrospinning solution. Temperature, humidity, operating voltage, and receiver rate were set to 25 °C, 45 ± 5%, 12 kV, and 1 mL / h, respectively. -1The rotation speed was controlled at 500 revolutions per minute. The obtained nanofiber membrane was vacuum dried at 60°C for 12 hours to obtain PAN-M as a blank control group.

[0069] 0.5 g of CP, 0.5 g of PIL, and 0.5 g of PAN (Mw = 100,000–180,000) were dissolved in 4.8 g of DMF and stirred for 10 h to form a uniformly dispersed CP / PIL@PAN electrospinning solution. Temperature, humidity, operating voltage, and receiver rate were set to 25 °C, 45 ± 5%, 12 kV, and 1 mL / h, respectively. -1 The rotation speed was controlled at 500 rpm. The obtained nanofiber membrane was vacuum dried at 60 °C for 12 h. The membrane was hot-pressed at 100 °C and 2 MPa to form a uniform and dense structure. CP / PIL@PAN-M was immersed in a solution containing an oxidant (230 mg ferric chloride and 5 mL methanol) for 12 h. The obtained membrane was washed with methanol and water and vacuum dried at 60 °C for 12 h to obtain PCP / PIL@PAN-M.

[0070] The preparation method of PCP@PAN-M is the same as that of PCP / PIL@PAN-M, the only difference being that PIL is omitted.

[0071] The microstructures of the PCP / PIL@PAN-M photothermal fiber membrane and the blank PAN-M fiber membrane without PCP and PIL obtained in this example under a scanning electron microscope are as follows: Figure 7 As shown. Compared to PAN-M, the uniform loading of PCP and PIL on PCP / PIL@PAN-M causes the fiber surface to become rough, forming a shell with photothermal properties.

[0072] The photothermal fiber membrane PCP / PIL@PAN-M obtained in this example operates at 1 kW / m². -2 The surface temperature of the polymer changes as follows after 30 minutes of simulated sunlight exposure: Figure 8 As shown, the photothermal film exhibits a rapid temperature response, reaching a maximum of 97.5℃, demonstrating excellent photothermal conversion capabilities.

[0073] Thermogravimetric analysis (TGA) diagram of the PCP / PIL@PAN-M photothermal fiber membrane obtained in this example is shown below. Figure 9 As shown, the polymer's initial decomposition temperature is around 300℃, and after heating to 900℃, the residue mass is about 52%, indicating good thermal stability.

[0074] Example 4

[0075] The application of photothermal composite films in evaporation under simulated sunlight is as follows:

[0076] The area is 2×2cm 2The sample membrane was embedded in polystyrene foam with buoyancy and heat insulation capabilities, and 100 ml of simulated seawater (3.5 wt% NaCl solution) was added to the volumetric beaker below. The evaporator was placed in a solar simulator with an AM1.5G filter, and the light intensity was calibrated to 1 kW m² using a photometer. -2 During the evaporation process, an infrared thermal imager recorded the surface temperature of the sample and stored it in a computer. An electronic analytical balance recorded the mass change of the evaporator in real time and calculated the evaporation rate. The results are as follows: Figure 10 and Figure 11 As shown. Figure 10 The results show that the photothermal film has a higher surface temperature than pure polyacrylonitrile fiber during evaporation. Figure 11 The medium-light thermal film reached 2.64 kg / m². -2 h -1 The evaporation rate was 7.8 times higher than that of pure polypropylene fiber membranes. Calculations showed that the photothermal film achieved a photothermal conversion efficiency of 97.59%.

[0077] Example 5

[0078] The application of photothermal composite membranes in seawater desalination under simulated sunlight is as follows:

[0079] The area is 2×2cm 2 The sample membrane PCP / PIL@PAN-M was embedded in polystyrene foam with buoyancy and heat insulation capabilities, and 100 ml of East China Sea seawater was added to the volumetric beaker below. The evaporator was placed in a solar simulator with an AM 1.5G filter, and the light intensity was calibrated using a photometer. Simultaneously, it was placed in a sealed, sloping-topped container, where the vapor condensed into fresh water at the top of the container and flowed into a recovery tank at the bottom. Figure 12 The results show that the concentration of metal ions—potassium, sodium, calcium, and magnesium—in the freshwater is 2-3 orders of magnitude lower than that in the original East China Sea, meeting the standards of the World Health Organization and demonstrating excellent water purification capabilities.

[0080] Example 6

[0081] The application of photothermal composite membranes in salt resistance during seawater desalination under simulated sunlight is as follows:

[0082] The evaporation process shown in Example 4 was cycled for 5 days, with 8 hours of testing each day. Two control groups were set up: one using a PCP-loaded polyacrylonitrile fiber membrane; the other using a PIL and PCP-loaded polyacrylonitrile fiber membrane. Figure 13 The image shows that after 8 cycles, obvious salt crystals appeared on the surface of the photothermal film without PIL. However, after 40 cycles, no salt precipitation was observed in the photothermal film with both PIL and PCP, demonstrating excellent salt resistance.

[0083] Example 7

[0084] The application of photothermal composite membranes in the purification of dye wastewater under simulated sunlight is as follows:

[0085] The area is 2×2cm 2 The sample membrane PCP / PIL@PAN-M was embedded in polystyrene foam with floating and heat-insulating capabilities, and 100 ml of 100 ppm methylene blue and rhodamine solutions were added to the volumetric beakers below. The evaporator was placed in a solar simulator with an AM 1.5G filter, and the light intensity was calibrated to 1 kWm using a photometer. -2 The UV-Vis absorption properties of the dye wastewater before and after purification were tested. For example... Figure 14 The results show that the purified organic dye wastewater is colorless and transparent, and its ultraviolet-visible absorption spectrum is consistent with that of pure water. This demonstrates excellent dye wastewater purification performance.

[0086] Example 8

[0087] The antibacterial application of photothermal composite films under light irradiation is specifically described as follows:

[0088] Cut the photothermal film PCP / PIL@PAN-M into 1x1cm pieces. 2 Identical blocks were incubated with bacteria (methicillin-resistant Staphylococcus aureus) in the dark for 20 minutes, and then 100 μL of the bacterial solution was used to coat the plate. Afterwards, the plate was incubated under light for 20 minutes, and then 100 μL of the bacterial solution was used to coat the plate. Figure 15 The results showed that the number of bacteria in the culture dish placed with pure polyacrylonitrile fiber membrane remained basically unchanged before and after light exposure; while the fiber membrane with added PCP and PIL almost completely eliminated the bacteria in the culture dish after 20 minutes of light exposure, demonstrating excellent antibacterial properties.

[0089] Traditional fiber membranes exhibit a salt concentration gradient between upper and lower regions during photothermal evaporation. When this gradient reaches saturation, it promotes salt crystallization, severely impacting evaporation performance and long-term usability. This invention offers stable and efficient evaporation, with wide applicability and controllable scale. The evaporation rate is consistently maintained at 2.64 kg / m³. -2 h -1 It also has multiple applications such as dye purification and antibacterial properties, effectively solving the problem of salt accumulation.

Claims

1. A composite fiber material, characterized in that, The composite fiber material comprises: porphyrin-based conjugated microporous polymer, amphoteric polyionic liquid, and polymer matrix; wherein the polymer matrix fiber is doped with porphyrin-based conjugated microporous polymer and amphoteric polyionic liquid; The porphyrin-based conjugated microporous polymer has the following structural formula: , where the wavy line represents a repeating unit; The amphoteric polyionic liquid has the following structural formula: , where n is 5000 or more.

2. The composite fiber material according to claim 1, characterized in that, The polymer matrix includes polyacrylonitrile, and the molecular weight of the polymer matrix is ​​100,000 to 180,000.

3. A method for preparing the composite fiber material according to claim 1, comprising: Porphyrin-based conjugated microporous monomers, amphoteric polyionic liquids, polymer matrix materials, and solvents are mixed and electrospun to obtain fiber membranes. The fiber membranes are then immersed in an oxidant solution to obtain composite fiber materials. The method for preparing the porphyrin-based conjugated microporous monomer includes: mixing acetic acid, nitrobenzene, and 3,5-bis(9H-carbazole-9-yl)benzaldehyde and heating to 100-120°C, then adding pyrrole and stirring the reaction for 0.5-2 hours, followed by purification to obtain the porphyrin-based conjugated microporous monomer; wherein the molar ratio of 3,5-bis(9H-carbazole-9-yl)benzaldehyde to pyrrole is 1:1-2.

4. The preparation method according to claim 3, characterized in that, The polymer matrix material includes polyacrylonitrile, with a molecular weight of 100,000 to 180,000; the solvent includes N,N-dimethylformamide.

5. The preparation method according to claim 3, characterized in that, The mass ratio of the porphyrin-based conjugated microporous monomer to the amphoteric polyionic liquid is (1~2):1; the total amount of the porphyrin-based conjugated microporous monomer and the amphoteric polyionic liquid is in the mass ratio of the polymer matrix material to the total amount of the polymer matrix material is (1~6):

1.

6. The preparation method according to claim 3, characterized in that, The oxidant solution is a methanol solution containing ferric chloride; wherein the ratio of ferric oxide to methanol is 150-200 mg: 2-10 mL.

7. The preparation method according to claim 3, characterized in that, The electrospinning process parameters include: temperature 20~30℃, humidity 40-50%, working voltage 8~14 kV, and receiver rate 1 mL / h. -1 The rotational speed is 400~700 rpm; The soaking time in the oxidant solution is 8-12 hours; The composite fibers undergo post-treatment after washing.

8. The preparation method according to claim 7, characterized in that, The post-processing is vacuum drying and / or hot pressing.

9. The application of the composite fiber material according to any one of claims 1-2 in the fields of seawater desalination, sewage purification, and sterilization.

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